Nano-manipulation of single DNA molecules

International Nuclear Information System (INIS)

Hu Jun; Shanghai Jiaotong Univ., Shanghai; Lv Junhong; Wang Guohua; Wang Ying; Li Minqian; Zhang Yi; Li Bin; Li Haikuo; An Hongjie

2004-01-01

Nano-manipulation of single atoms and molecules is a critical technique in nanoscience and nanotechnology. This review paper will focus on the recent development of the manipulation of single DNA molecules based on atomic force microscopy (AFM). Precise manipulation has been realized including varied manipulating modes such as 'cutting', 'pushing', 'folding', 'kneading', 'picking up', 'dipping', etc. The cutting accuracy is dominated by the size of the AFM tip, which is usually 10 nm or less. Single DNA fragments can be cut and picked up and then amplified by single molecule PCR. Thus positioning isolation and sequencing can be performed. (authors)

DNA in the material world: electrical properties and nano-applications.

Science.gov (United States)

Triberis, Georgios P; Dimakogianni, Margarita

2009-01-01

Contradictory experimental findings and theoretical interpretations have spurred intense debate over the electrical properties of the DNA double helix. In the present review article the various factors responsible for these divergences are discussed. The enlightenment of this issue could improve long range chemistry of oxidative DNA damage and repair processes, monitoring protein-DNA interactions and possible applications in nano-electronic circuit technology. The update experimental situation concerning measurements of the electrical conductivity is given. The character of the carriers responsible for the electrical conductivity measured in DNA is investigated. A theoretical model for the temperature dependence of the electrical conductivity of DNA is presented, based on microscopic models and percolation theoretical arguments. The theoretical results, excluding or including correlation effects, are applied to recent experimental findings for DNA, considering it as a one dimensional molecular wire. The results indicate that correlation effects are probably responsible for large hopping distances in DNA samples. Other theoretical conductivity models proposed for the interpretation of the responsible transport mechanism are also reviewed. Some of the most known and pioneering works on DNA's nano-applications, future developments and perspectives along with current technological limitations and patents are presented and discussed.

Ball with hair: modular functionalization of highly stable G-quadruplex DNA nano-scaffolds through N2-guanine modification.

Science.gov (United States)

Lech, Christopher Jacques; Phan, Anh Tuân

2017-06-20

Functionalized nanoparticles have seen valuable applications, particularly in the delivery of therapeutic and diagnostic agents in biological systems. However, the manufacturing of such nano-scale systems with the consistency required for biological application can be challenging, as variation in size and shape have large influences in nanoparticle behavior in vivo. We report on the development of a versatile nano-scaffold based on the modular functionalization of a DNA G-quadruplex. DNA sequences are functionalized in a modular fashion using well-established phosphoramidite chemical synthesis with nucleotides containing modification of the amino (N2) position of the guanine base. In physiological conditions, these sequences fold into well-defined G-quadruplex structures. The resulting DNA nano-scaffolds are thermally stable, consistent in size, and functionalized in a manner that allows for control over the density and relative orientation of functional chemistries on the nano-scaffold surface. Various chemistries including small modifications (N2-methyl-guanine), bulky aromatic modifications (N2-benzyl-guanine), and long chain-like modifications (N2-6-amino-hexyl-guanine) are tested and are found to be generally compatible with G-quadruplex formation. Furthermore, these modifications stabilize the G-quadruplex scaffold by 2.0-13.3 °C per modification in the melting temperature, with concurrent modifications producing extremely stable nano-scaffolds. We demonstrate the potential of this approach by functionalizing nano-scaffolds for use within the biotin-avidin conjugation approach. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

Topological and metric properties of linear and circular DNA chains in nano-slits and nano-channels

Science.gov (United States)

Orlandini, Enzo; Micheletti, Cristian

2014-03-01

Motivated by recent advancements in single DNA molecule experiments, based on nanofluidic devices, we investigate numerically the metric and topological properties of a modelof open and circular DNA chains confined inside nano-slits and nano-channles. The results reveal an interesting characterization of the metric crossover behaviour in terms of the abundance, type and length of occuring knots. In particular we find that the knotting probability is nonmonotonic for increasing confinement and can be largely enhanced or suppressed, compared to the bulk case, by simply varying the slit or channel trasversal dimension. The observed knot population consists of knots that are far simpler than for DNA chains in spherical (i.e. cavities or capsids) confinement. These results suggest that nanoslits and nanochannels can be properly designed to produce open DNA chains hosting simple knots or to sieve DNA rings according to their knotted state. Finally we discuss the implications that the presence of knots may have on the dynamical properties of confined DNA chains such as chain elongation, injection/ejection processes and entanglement relaxation. We acknowledge financial support from the Italian ministry of education, grant PRIN 2010HXAW77.

Protection of cisplatin-induced spermatotoxicity, DNA damage and chromatin abnormality by selenium nano-particles

Energy Technology Data Exchange (ETDEWEB)

Rezvanfar, Mohammad Amin; Rezvanfar, Mohammad Ali [Department of Toxicology and Pharmacology, Faculty of Pharmacy, and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences (TUMS), Tehran (Iran, Islamic Republic of); Shahverdi, Ahmad Reza [Department of Pharmaceutical Biotechnology and Biotechnology Research Centre, Faculty of Pharmacy, TUMS, Tehran (Iran, Islamic Republic of); Ahmadi, Abbas [Department of Histology and Embryology, Faculty of Veterinary Medicine, Urmia University, Urmia (Iran, Islamic Republic of); Baeeri, Maryam; Mohammadirad, Azadeh [Department of Toxicology and Pharmacology, Faculty of Pharmacy, and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences (TUMS), Tehran (Iran, Islamic Republic of); Abdollahi, Mohammad, E-mail: mohammad.abdollahi@utoronto.ca [Department of Toxicology and Pharmacology, Faculty of Pharmacy, and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences (TUMS), Tehran (Iran, Islamic Republic of)

2013-02-01

Cisplatin (CIS), an anticancer alkylating agent, induces DNA adducts and effectively cross links the DNA strands and so affects spermatozoa as a male reproductive toxicant. The present study investigated the cellular/biochemical mechanisms underlying possible protective effect of selenium nano-particles (Nano-Se) as an established strong antioxidant with more bioavailability and less toxicity, on reproductive toxicity of CIS by assessment of sperm characteristics, sperm DNA integrity, chromatin quality and spermatogenic disorders. To determine the role of oxidative stress (OS) in the pathogenesis of CIS gonadotoxicity, the level of lipid peroxidation (LPO), antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) and peroxynitrite (ONOO) as a marker of nitrosative stress (NS) and testosterone (T) concentration as a biomarker of testicular function were measured in the blood and testes. Thirty-two male Wistar rats were equally divided into four groups. A single IP dose of CIS (7 mg/kg) and protective dose of Nano-Se (2 mg/kg/day) were administered alone or in combination. The CIS-exposed rats showed a significant increase in testicular and serum LPO and ONOO level, along with a significant decrease in enzymatic antioxidants levels, diminished serum T concentration and abnormal histologic findings with impaired sperm quality associated with increased DNA damage and decreased chromatin quality. Coadministration of Nano-Se significantly improved the serum T, sperm quality, and spermatogenesis and reduced CIS-induced free radical toxic stress and spermatic DNA damage. In conclusion, the current study demonstrated that Nano-Se may be useful to prevent CIS-induced gonadotoxicity through its antioxidant potential. Highlights: ► Cisplatin (CIS) affects spermatozoa as a male reproductive toxicant. ► Effect of Nano-Se on CIS-induced spermatotoxicity was investigated. ► CIS-exposure induces oxidative sperm DNA damage

Radiation synthesis of the nano-scale materials

Energy Technology Data Exchange (ETDEWEB)

Yonghong, Ni; Zhicheng, Zhang; Xuewu, Ge; Xiangling, Xu [Department of Applied Chemistry, Univ. of Science and Technology of China, Hefei (China)

2000-03-01

Some recent research jobs on fabricating the nano-scale materials via {gamma}-irradiation in our laboratory are simply summarized in this paper. The main contents contain four aspects: (1) the preparation of metal alloy - powders; (2) the fabrication of polymer -metal nano-composites in aqueous solution, micro-emulsion and emulsion systems; (3) the synthesis of metal sulfide nano-particles and (4) the preparation of the ordered nano-structure materials. The corresponding preparation processes are also simply described. (author)

Radiation synthesis of the nano-scale materials

International Nuclear Information System (INIS)

Ni Yonghong; Zhang Zhicheng; Ge Xuewu; Xu Xiangling

2000-01-01

Some recent research jobs on fabricating the nano-scale materials via γ-irradiation in our laboratory are simply summarized in this paper. The main contents contain four aspects: (1) the preparation of metal alloy - powders; (2) the fabrication of polymer -metal nano-composites in aqueous solution, micro-emulsion and emulsion systems; (3) the synthesis of metal sulfide nano-particles and (4) the preparation of the ordered nano-structure materials. The corresponding preparation processes are also simply described. (author)

Density functional theory studies on the nano-scaled composites consisted of graphene and acyl hydrazone molecules

Science.gov (United States)

Ren, J. L.; Zhou, L.; Lv, Z. C.; Ding, C. H.; Wu, Y. H.; Bai, H. C.

2016-07-01

Graphene, which is the first obtained single atomic layer 2D materials, has drawn a great of concern in nano biotechnology due to the unique property. On one hand, acyl hydrazone compounds belonging to the Schif bases have aroused considerable attention in medicine, pharmacy, and analytical reagent. However, few understanding about the interaction between graphene and acyl hydrazone molecules is now available. And such investigations are much crucial for the applications of these new nano-scaled composites. The current work revealed theoretical investigations on the nano-scaled composites built by acyl hydrazone molecules loaded on the surface of graphene. The relative energy, electronic property and the interaction between the counterparts of graphene/acyl hydrazone composites are investigated based on the density functional theory calculations. According to the obtained adsorption energy, the formation of the nano-scaled composite from the isolated graphene and acyl hydrazone molecule is exothermic, and thus it is energetically favorable to form these nano composites in viewpoint of total energy change. The frontier molecular orbital for the nano composite is mainly distributed at the graphene part, leading to that the energy levels of the frontier molecular orbital of the nano composites are very close to that of isolated graphene. Moreover, the counterpart interaction for the graphene/acyl hydrazone composites is also explored based on the discussions of orbital hybridization, charge redistribution and Van der Waals interaction.

NanoRNase from Aeropyrum pernix shows nuclease activity on ssDNA and ssRNA.

Science.gov (United States)

Deng, Yong-Jie; Feng, Lei; Zhou, Huan; Xiao, Xiang; Wang, Feng-Ping; Liu, Xi-Peng

2018-05-01

In cells, degrading DNA and RNA by various nucleases is very important. These processes are strictly controlled and regulated to maintain DNA integrity and to mature or recycle various RNAs. NanoRNase (Nrn) is a 3'-exonuclease that specifically degrades nanoRNAs shorter than 5 nucleotides. Several Nrns have been identified and characterized in bacteria, mainly in Firmicutes. Archaea often grow in extreme environments and might be subjected to more damage to DNA/RNA, so DNA repair and recycling of damaged RNA are very important in archaea. There is no report on the identification and characterization of Nrn in archaea. Aeropyrum pernix encodes three potential Nrns: NrnA (Ape1437), NrnB (Ape0124), and an Nrn-like protein Ape2190. Biochemical characterization showed that only Ape0124 could degrade ssDNA and ssRNA from the 3'-end in the presence of Mn 2+ . Interestingly, unlike bacterial Nrns, Ape0124 prefers ssDNA, including short nanoDNA, and degrades nanoRNA with lower efficiency. The 3'-DNA backbone was found to be required for efficiently hydrolyzing the phosphodiester bonds. In addition, Ape0124 also degrads the 3'-overhang of double-stranded DNA. Interestingly, Ape0124 could hydrolyze pAp into AMP, which is a feature of bacterial NrnA, not NrnB. Our results indicate that Ape0124 is a novel Nrn with a combined substrate profile of bacterial NrnA and NrnB. Copyright © 2018 Elsevier B.V. All rights reserved.

Scaling laws for nanoFET sensors

International Nuclear Information System (INIS)

Zhou Fushan; Wei Qihuo

2008-01-01

The sensitive conductance change of semiconductor nanowires and carbon nanotubes in response to the binding of charged molecules provides a novel sensing modality which is generally denoted as nanoFET sensors. In this paper, we study the scaling laws of nanoplate FET sensors by simplifying nanoplates as random resistor networks with molecular receptors sitting on lattice sites. Nanowire/tube FETs are included as the limiting cases where the device width goes small. Computer simulations show that the field effect strength exerted by the binding molecules has significant impact on the scaling behaviors. When the field effect strength is small, nanoFETs have little size and shape dependence. In contrast, when the field effect strength becomes stronger, there exists a lower detection threshold for charge accumulation FETs and an upper detection threshold for charge depletion FET sensors. At these thresholds, the nanoFET devices undergo a transition between low and large sensitivities. These thresholds may set the detection limits of nanoFET sensors, while they could be eliminated by designing devices with very short source-drain distance and large width

Topology optimization for nano-scale heat transfer

DEFF Research Database (Denmark)

Evgrafov, Anton; Maute, Kurt; Yang, Ronggui

2009-01-01

We consider the problem of optimal design of nano-scale heat conducting systems using topology optimization techniques. At such small scales the empirical Fourier's law of heat conduction no longer captures the underlying physical phenomena because the mean-free path of the heat carriers, phonons...... in our case, becomes comparable with, or even larger than, the feature sizes of considered material distributions. A more accurate model at nano-scales is given by kinetic theory, which provides a compromise between the inaccurate Fourier's law and precise, but too computationally expensive, atomistic...

Scaling Laws for NanoFET Sensors

Science.gov (United States)

Wei, Qi-Huo; Zhou, Fu-Shan

2008-03-01

In this paper, we report our numerical studies of the scaling laws for nanoplate field-effect transistor (FET) sensors by simplifying the nanoplates as random resistor networks. Nanowire/tube FETs are included as the limiting cases where the device width goes small. Computer simulations show that the field effect strength exerted by the binding molecules has significant impact on the scaling behaviors. When the field effect strength is small, nanoFETs have little size and shape dependence. In contrast, when the field-effect strength becomes stronger, there exists a lower detection threshold for charge accumulation FETs and an upper detection threshold for charge depletion FET sensors. At these thresholds, the nanoFET devices undergo a transition between low and large sensitivities. These thresholds may set the detection limits of nanoFET sensors. We propose to eliminate these detection thresholds by employing devices with very short source-drain distance and large width.

Design and Assembly of DNA Nano-Objects and 2D DNA Origami Arrays

Science.gov (United States)

Liu, Wenyan

DNA, which plays a central role in biology as the carrier of genetic information, is also an excellent candidate for structural nanotechnology. Researches have proven that a variety of complicated DNA assemblies, such as objects, 2D & 3D crystals, and nanomechanical devices, can be fabricated through the combination of robust branched DNA motifs and sticky ends. This dissertation focuses on the design and construction of DNA nano--objects and 2D DNA origami arrays. In this dissertation, we first describe the formation of a triangular species that has four strands per edge, held together by PX interactions. We demonstrate by nondenaturing gel electrophoresis and by atomic force microscopy (AFM) that we can combine a partial triangle with other strands to form a robust four--stranded molecule. By combining them with a novel three--domain molecule, we also demonstrate by AFM that these triangles can be self--assembled into a linear array. Second, we demonstrate our attempts to design and self--assemble 2D DNA origami arrays using several different strategies. Specifically, we introduce the self--assembly of 2D DNA origami lattices using a symmetric cross--like design. This design strategy resulted in a well--ordered woven latticework array with edge dimensions of 2--3 mum. This size is likely to be large enough to connect bottom-up methods of patterning with top--down approaches. Third, we illustrate the design and construction of DNA nano--objects for exploring the substrate preferences of topoisomerase (topo) II. We designed and fabricated four double rhombus--like DNA molecules, each of which contains a different conformation of crossover in the middle, as possible substrates to establish the structural preferences for topo II. We characterized the formation of each substrate molecule by gel electrophoresis. Finally, we study the effect of M13 DNA knotting on the formation of the DNA origami tiles. We demonstrate by atomic force microscopy (AFM) that knotted M13

Computer simulations for the nano-scale

International Nuclear Information System (INIS)

Stich, I.

2007-01-01

A review of methods for computations for the nano-scale is presented. The paper should provide a convenient starting point into computations for the nano-scale as well as a more in depth presentation for those already working in the field of atomic/molecular-scale modeling. The argument is divided in chapters covering the methods for description of the (i) electrons, (ii) ions, and (iii) techniques for efficient solving of the underlying equations. A fairly broad view is taken covering the Hartree-Fock approximation, density functional techniques and quantum Monte-Carlo techniques for electrons. The customary quantum chemistry methods, such as post Hartree-Fock techniques, are only briefly mentioned. Description of both classical and quantum ions is presented. The techniques cover Ehrenfest, Born-Oppenheimer, and Car-Parrinello dynamics. The strong and weak points of both principal and technical nature are analyzed. In the second part we introduce a number of applications to demonstrate the different approximations and techniques introduced in the first part. They cover a wide range of applications such as non-simple liquids, surfaces, molecule-surface interactions, applications in nano technology, etc. These more in depth presentations, while certainly not exhaustive, should provide information on technical aspects of the simulations, typical parameters used, and ways of analysis of the huge amounts of data generated in these large-scale supercomputer simulations. (author)

Mechanics over micro and nano scales

CERN Document Server

Chakraborty, Suman

2011-01-01

Discusses the fundaments of mechanics over micro and nano scales in a level accessible to multi-disciplinary researchers, with a balance of mathematical details and physical principles Covers life sciences and chemistry for use in emerging applications related to mechanics over small scales Demonstrates the explicit interconnection between various scale issues and the mechanics of miniaturized systems

Method of producing exfoliated graphite, flexible graphite, and nano-scaled graphene platelets

Science.gov (United States)

Zhamu, Aruna; Shi, Jinjun; Guo, Jiusheng; Jang, Bor Z.

2010-11-02

The present invention provides a method of exfoliating a layered material (e.g., graphite and graphite oxide) to produce nano-scaled platelets having a thickness smaller than 100 nm, typically smaller than 10 nm. The method comprises (a) dispersing particles of graphite, graphite oxide, or a non-graphite laminar compound in a liquid medium containing therein a surfactant or dispersing agent to obtain a stable suspension or slurry; and (b) exposing the suspension or slurry to ultrasonic waves at an energy level for a sufficient length of time to produce separated nano-scaled platelets. The nano-scaled platelets are candidate reinforcement fillers for polymer nanocomposites. Nano-scaled graphene platelets are much lower-cost alternatives to carbon nano-tubes or carbon nano-fibers.

The value of fluorimetry (Qubit) and spectrophotometry (NanoDrop) in the quantification of cell-free DNA (cfDNA) in malignant melanoma and prostate cancer patients.

Science.gov (United States)

Ponti, Giovanni; Maccaferri, Monia; Manfredini, Marco; Kaleci, Shaniko; Mandrioli, Mauro; Pellacani, Giovanni; Ozben, Tomris; Depenni, Roberta; Bianchi, Giampaolo; Pirola, Giacomo Maria; Tomasi, Aldo

2018-04-01

Circulating cell-free tumor DNA (cfDNA) is of crucial interest in oncology. cfDNA constitutes a potential prognostic and therapeutic marker for different solid tumors and can be used in the diagnostic and therapeutic management of cancer patients for which nowadays there are no valid laboratory markers. In the present study, the quality and quantity of the cfDNA were assessed by different quantification procedures, in order to identify the potential applications of these techniques in the preliminary cfDNA quantification. Qubit with single (ss) and double strand (ds) DNA assay kits, NanoDrop and quantitative Real Time PCR (qPCR), were adopted to assess the cfDNA in the blood samples of 18 melanoma patients, 67 prostate cancer patients and 15 healthy controls. The quantification by NanoDrop (average value 8.48ng/μl, 95% confidence limit (CL)=7.23-9.73), Qubit ssDNA (average value 23.08ng/μl, CL=19.88-26.28), dsDNA (average value 4.32ng/μl, CL=3.52-5.12) assay kits and qPCR (average value 0.39ng/μl, CL=0.31-0.47) revealed differences among the four procedures. Qubit 2.0 ss-DNA kit gave higher cfDNA concentration values for all the samples analyzed. In detail, Qubit ssDNA assay revealed higher sensitivity in the quantification of small amounts of pure ss-DNA and ds-DNA, while NanoDrop allowed the assessment of the purity of cfDNA samples. The NanoDrop and Qubit 2.0 measurements were analyzed in order to define their correlation with qPCR cfDNA assessment, showing good correlation values with the qPCR that should be considered the "gold standard". In our proposal, the sequential combination of NanoDrop and Qubit ssDNA methods should be adopted for a cost-effective preliminary assessment of total circulating cfDNA in melanoma and prostate cancer patients, and only discordant values should undergo qPCR assessment. Copyright © 2018 Elsevier B.V. All rights reserved.

Closed-looped in situ nano processing on a culturing cell using an inverted electron beam lithography system

International Nuclear Information System (INIS)

Hoshino, Takayuki; Mabuchi, Kunihiko

2013-01-01

Highlights: ► An electron beam lithography (EBL) was used as an in situ nano processing for a living cell. ► A synchronized optics was containing an inverted EBL and an optical microscope. ► This system visualized real-time images of the EB-induced nano processing. ► We demonstrated the nano processing for a culturing cell with 200–300 nm resolution. ► Our system would be able to provide high resolution display of virtual environments. -- Abstract: The beam profile of an electron beam (EB) can be focused onto less than a nanometer spot and scanned over a wide field with extremely high speed sweeping. Thus, EB is employed for nano scale lithography in applied physics research studies and in fabrication of semiconductors. We applied a scanning EB as a control system for a living cell membrane which is representative of large scale complex systems containing nanometer size components. First, we designed the opposed co-axial dual optics containing inverted electron beam lithography (I-EBL) system and a fluorescent optical microscope. This system could provide in situ nano processing for a culturing living cell on a 100-nm-thick SiN nanomembrane, which was placed between the I-EBL and the fluorescent optical microscope. Then we demonstrated the EB-induced chemical direct nano processing for a culturing cell with hundreds of nanometer resolution and visualized real-time images of the scanning spot of the EB-induced luminescent emission and chemical processing using a high sensitive camera mounted on the optical microscope. We concluded that our closed-loop in situ nano processing would be able to provide a nanometer resolution display of virtual molecule environments to study functional changes of bio-molecule systems

DNA damage on nano- and micrometer scales impacts dicentric induction: computer modelling of ion microbeam experiments

Science.gov (United States)

Friedland, Werner; Kundrat, Pavel; Schmitt, Elke

2016-07-01

Detailed understanding of the enhanced relative biological effectiveness (RBE) of ions, in particular at high linear energy transfer (LET) values, is needed to fully explore the radiation risk of manned space missions. It is generally accepted that the enhanced RBE of high-LET particles results from the DNA lesion patterns, in particular DNA double-strand breaks (DSB), due to the spatial clustering of energy deposits around their trajectories. In conventional experiments on biological effects of radiation types of diverse quality, however, clustering of energy deposition events on nanometer scale that is relevant for the induction and local complexity of DSB is inherently interlinked with regional (sub-)micrometer-scale DSB clustering along the particle tracks. Due to this limitation, the role of both (nano- and micrometer) scales on the induction of diverse biological endpoints cannot be frankly separated. To address this issue in a unique way, experiments at the ion microbeam SNAKE [1] and corresponding track-structure based model calculations of DSB induction and subsequent repair with the biophysical code PARTRAC [2] have been performed. In the experiments, hybrid human-hamster A_{L} cells were irradiated with 20 MeV (2.6 keV/μm) protons, 45 MeV (60 keV/μm) lithium ions or 55 MeV (310 keV/μm) carbon ions. The ions were either quasi-homogeneously distributed or focused to 0.5 x 1 μm^{2} spots on regular matrix patterns of 5.4 μm, 7.6 μm and 10.6 μm grid size, with pre-defined particle numbers per spot so as to deposit a mean dose of 1.7 Gy for all irradiation patterns. As expected, the induction of dicentrics by homogeneous irradiation increased with LET: lithium and carbon ions induced about two- and four-fold higher yields of dicentrics than protons. The induction of dicentrics is, however, affected by µm-scale, too: focusing 20 lithium ions or 451 protons per spot on a 10.6 μm grid induced two or three times more dicentrics, respectively, than a

Nano-Scale Positioning Design with Piezoelectric Materials

Directory of Open Access Journals (Sweden)

Yung Yue Chen

2017-12-01

Full Text Available Piezoelectric materials naturally possess high potential to deliver nano-scale positioning resolution; hence, they are adopted in a variety of engineering applications widely. Unfortunately, unacceptable positioning errors always appear because of the natural hysteresis effect of the piezoelectric materials. This natural property must be mitigated in practical applications. For solving this drawback, a nonlinear positioning design is proposed in this article. This nonlinear positioning design of piezoelectric materials is realized by the following four steps: 1. The famous Bouc–Wen model is utilized to present the input and output behaviors of piezoelectric materials; 2. System parameters of the Bouc–Wen model that describe the characteristics of piezoelectric materials are simultaneously identified with the particle swam optimization method; 3. Stability verification for the identified Bouc–Wen model; 4. A nonlinear feedback linearization control design is derived for the nano-scale positioning design of the piezoelectric material, mathematically. One important contribution of this investigation is that the positioning error between the output displacement of the controlled piezoelectric materials and the desired trajectory in nano-scale level can be proven to converge to zero asymptotically, under the effect of the hysteresis.

The silicon chip: A versatile micro-scale platform for micro- and nano-scale systems

Science.gov (United States)

Choi, Edward

Cutting-edge advances in micro- and nano-scale technology require instrumentation to interface with the external world. While technology feature sizes are continually being reduced, the size of experimentalists and their instrumentation do not mirror this trend. Hence there is a need for effective application-specific instrumentation to bridge the gap from the micro and nano-scale phenomena being studied to the comparative macro-scale of the human interfaces. This dissertation puts forward the idea that the silicon CMOS integrated circuit, or microchip in short, serves as an excellent platform to perform this functionality. The electronic interfaces designed for the semiconductor industry are particularly attractive as development platforms, and the reduction in feature sizes that has been a hallmark of the industry suggests that chip-scale instrumentation may be more closely coupled to the phenomena of interest, allowing finer control or improved measurement capabilities. Compatibility with commercial processes will further enable economies of scale through mass production, another welcome feature of this approach. Thus chip-scale instrumentation may replace the bulky, expensive, cumbersome-to-operate macro-scale prototypes currently in use for many of these applications. The dissertation examines four specific applications in which the chip may serve as the ideal instrumentation platform. These are nanorod manipulation, polypyrrole bilayer hinge microactuator control, organic transistor hybrid circuits, and contact fluorescence imaging. The thesis is structured around chapters devoted to each of these projects, in addition to a chapter on preliminary work on an RFID system that serves as a wireless interface model. Each of these chapters contains tools and techniques developed for chip-scale instrumentation, from custom scripts for automated layout and data collection to microfabrication processes. Implementation of these tools to develop systems for the

Amplification of pico-scale DNA mediated by bacterial carrier DNA for small-cell-number transcription factor ChIP-seq

DEFF Research Database (Denmark)

Jakobsen, Janus S; Bagger, Frederik O; Hasemann, Marie S

2015-01-01

BACKGROUND: Chromatin-Immunoprecipitation coupled with deep sequencing (ChIP-seq) is used to map transcription factor occupancy and generate epigenetic profiles genome-wide. The requirement of nano-scale ChIP DNA for generation of sequencing libraries has impeded ChIP-seq on in vivo tissues of low...... transcription factor (CEBPA) and histone mark (H3K4me3) ChIP. We further demonstrate that genomic profiles are highly resilient to changes in carrier DNA to ChIP DNA ratios. CONCLUSIONS: This represents a significant advance compared to existing technologies, which involve either complex steps of pre...... cell numbers. RESULTS: We describe a robust, simple and scalable methodology for ChIP-seq of low-abundant cell populations, verified down to 10,000 cells. By employing non-mammalian genome mapping bacterial carrier DNA during amplification, we reliably amplify down to 50 pg of ChIP DNA from...

MD Simulation on Collision Behavior Between Nano-Scale TiO₂ Particles During Vacuum Cold Spraying.

Science.gov (United States)

Yao, Hai-Long; Yang, Guan-Jun; Li, Chang-Jiu

2018-04-01

Particle collision behavior influences significantly inter-nano particle bonding formation during the nano-ceramic coating deposition by vacuum cold spraying (or aerosol deposition method). In order to illuminate the collision behavior between nano-scale ceramic particles, molecular dynamic simulation was applied to explore impact process between nano-scale TiO2 particles through controlling impact velocities. Results show that the recoil efficiency of the nano-scale TiO2 particle is decreased with the increase of the impact velocity. Nano-scale TiO2 particle exhibits localized plastic deformation during collision at low velocities, while it is intensively deformed by collision at high velocities. This intensive deformation promotes the nano-particle adhesion rather than rebounding off. A relationship between the adhesion energy and the rebound energy is established for the bonding formation of the nano-scale TiO2 particle. The adhesion energy required to the bonding formation between nano-scale ceramic particles can be produced by high velocity collision.

Method of producing carbon coated nano- and micron-scale particles

Science.gov (United States)

Perry, W. Lee; Weigle, John C; Phillips, Jonathan

2013-12-17

A method of making carbon-coated nano- or micron-scale particles comprising entraining particles in an aerosol gas, providing a carbon-containing gas, providing a plasma gas, mixing the aerosol gas, the carbon-containing gas, and the plasma gas proximate a torch, bombarding the mixed gases with microwaves, and collecting resulting carbon-coated nano- or micron-scale particles.

Aptamer-conjugated DNA nano-ring as the carrier of drug molecules

Science.gov (United States)

Srivithya, Vellampatti; Roun, Heo; Sekhar Babu, Mitta; Hyung, Park Jae; Ha, Park Sung

2018-03-01

Due to its predictable self-assembly and structural stability, structural DNA nanotechnology is considered one of the main interdisciplinary subjects encompassing conventional nanotechnology and biotechnology. Here we have fabricated the mucin aptamer (MUC1)˗conjugated DNA nano˗ring intercalated with doxorubicin (DNRA˗DOX) as potential therapeutics for breast cancer. DNRA˗DOX exhibited significantly higher cytotoxicity to the MCF˗7 breast cancer cells than the controls, including DOX alone and the aptamer deficient DNA nano˗ring (DNR) with doxorubicin. Interactions between DOX and DNRA were studied using spectrophotometric measurements. Dose-dependent cytotoxicity was performed to prove that both DNR and DNRA were non-toxic to the cells. The drug release profile showed a controlled release of DOX at normal physiological pH 7.4, with approximately 61% released, but when exposed to lysosomal of pH 5.5, the corresponding 95% was released within 48 h. Owing to the presence of the aptamer, DNRA˗DOX was effectively taken up by the cancer cells, as confirmed by confocal microscopy, implying that it has potential for use in targeted drug delivery.

Design exploration of emerging nano-scale non-volatile memory

CERN Document Server

Yu, Hao

2014-01-01

This book presents the latest techniques for characterization, modeling and design for nano-scale non-volatile memory (NVM) devices.  Coverage focuses on fundamental NVM device fabrication and characterization, internal state identification of memristic dynamics with physics modeling, NVM circuit design, and hybrid NVM memory system design-space optimization. The authors discuss design methodologies for nano-scale NVM devices from a circuits/systems perspective, including the general foundations for the fundamental memristic dynamics in NVM devices.  Coverage includes physical modeling, as well as the development of a platform to explore novel hybrid CMOS and NVM circuit and system design.   • Offers readers a systematic and comprehensive treatment of emerging nano-scale non-volatile memory (NVM) devices; • Focuses on the internal state of NVM memristic dynamics, novel NVM readout and memory cell circuit design, and hybrid NVM memory system optimization; • Provides both theoretical analysis and pr...

A portable pulmonary delivery system for nano engineered DNA vaccines driven by surface acoustic wave devices

International Nuclear Information System (INIS)

Rajapaksa, A.E.; Qi, Aisha; Yeo, L.; Friend, J.

2010-01-01

Full text: The increase in the need for effective delivery of potelll vaccines against infectious diseases, require robust yet straightforward pro duction of encapsulated DNA-laden aerosols. Aerosol delivery of drugs represents the next generation of vaccine delivery where the drug is deposited into the lung, which provides an ideal, non-invasive route. Moreover, several features of D A vaccines make them more attractive than conventional vaccines; thus, DNA vaccines have gained global interest for a variety of applications. However, several limitations such as ineffective cellular uptake and intracellular delivery, and degradation of DNA need to be overcome before clin ical applications. In this study, a novel and scalable engineered technique has been developed to create a biodegradable polymer system, which enables controlled delivery of a well designed DNA vaccine for immuno-therapeutics. Surface Acoustic Wave (SAW) atomisation has been found as useful mechanism for atomising fluid samples for medical and industrial devices. It is a straightforward method for synthesising un-agglomerated biodegradable nanoparti cles (<250 nm) in the absence of organic solvents which would represent a major breakthrough for biopharmaceutical encapsulation and delivery. Nano-scale polymer particles for DNA vaccines deliv ery were obtained through an evaporative process of the initial aerosol created by surface acoustic waves at 8-150 MHz, the final size of which could be controlled by modifying the initial polymer concen tration and solid contents. Thus, SAW atomiser represents a promising alternative for the development of a low power device for producing nano-engineered vaccines with a controlled and narrow size distribution as delivery system for genetic immuno-therapeutics.

Preparation and Characterization of Super-paramagnetic Nano-beads for DNA Isolation

Institute of Scientific and Technical Information of China (English)

Xin XIE; Xu ZHANG; Bing Bin YU; wei Yang FE

2004-01-01

Unique coupling reagent, bis-(2-hydroxyethyl methacrylate) phosphate was used to prepare coated and functionalized superparamagnetic nanobeads, leading to a simple, effective method for coating the nanobeads. With this method, the thickness of the coating layer and the functional group contents on the nano-beads could be controlled by changing the quantity of the coated monomers. The nanobeads were characterized by means of transmission electron microscopy (TEM) and Fourier transformation infrared spectroscopy (FTIR). The carboxyl-modified magnetic nano-beads were employed to streamline the protocol of isolation of genomic DNA from the human whole blood.

Bioinspiration From Nano to Micro Scales

CERN Document Server

2012-01-01

Methods in bioinspiration and biomimicking have been around for a long time. However, due to current advances in modern physical, biological sciences, and technologies, our understanding of the methods have evolved to a new level. This is due not only to the identification of mysterious and fascinating phenomena but also to the understandings of the correlation between the structural factors and the performance based on the latest theoretical, modeling, and experimental technologies. Bioinspiration: From Nano to Micro Scale provides readers with a broad view of the frontiers of research in the area of bioinspiration from the nano to macroscopic scales, particularly in the areas of biomineralization, antifreeze protein, and antifreeze effect. It also covers such methods as the lotus effect and superhydrophobicity, structural colors in animal kingdom and beyond, as well as behavior in ion channels. A number of international experts in related fields have contributed to this book, which offers a comprehensive an...

An active nano-supported interface designed from gold nanoparticles embedded on ionic liquid for depositing DNA

International Nuclear Information System (INIS)

Lu Liping; Kang Tianfang; Cheng Shuiyuan; Guo Xiurui

2009-01-01

The use of an active nano-interface designed from gold nanoparticles embedded on ionic liquid for DNA damage resulted from formalehyde (HCHO) is reported in this article. The active nano-interface was fabricated by depositing gold nanoparticles on the ionic liquid 1-butyl-3-methylimidazolium tetrafluroborate ([bmim][BF 4 ]). A glassy carbon electrode modified by this composite film was fabricated to immobilize DNA for probing into the damage resulted from HCHO. The modifying process was characterized by X-ray photoelectron spectroscopy, atomic force microscopy and electrochemistry involving electrochemical impedance spectroscopy. It was found that the modified film performs effectively in studying the DNA damage by electrocatalytic activity toward HCHO oxidation.

Charge transport through exciton shelves in cadmium chalcogenide quantum dot-DNA nano-bioelectronic thin films

Science.gov (United States)

Goodman, Samuel M.; Noh, Hyunwoo; Singh, Vivek; Cha, Jennifer N.; Nagpal, Prashant

2015-02-01

Quantum dot (QD), or semiconductor nanocrystal, thin films are being explored for making solution-processable devices due to their size- and shape-tunable bandgap and discrete higher energy electronic states. While DNA has been extensively used for the self-assembly of nanocrystals, it has not been investigated for the simultaneous conduction of multiple energy charges or excitons via exciton shelves (ES) formed in QD-DNA nano-bioelectronic thin films. Here, we present studies on charge conduction through exciton shelves, which are formed via chemically coupled QDs and DNA, between electronic states of the QDs and the HOMO-LUMO levels in the complementary DNA nucleobases. While several challenges need to be addressed in optimizing the formation of devices using QD-DNA thin films, a higher charge collection efficiency for hot-carriers and our detailed investigations of charge transport mechanism in these thin films highlight their potential for applications in nano-bioelectronic devices and biological transducers.

Charge transport through exciton shelves in cadmium chalcogenide quantum dot-DNA nano-bioelectronic thin films

Energy Technology Data Exchange (ETDEWEB)

Goodman, Samuel M.; Singh, Vivek [Department of Chemical and Biological Engineering, University of Colorado Boulder, 3415 Colorado Avenue, Boulder, Colorado 80303 (United States); Noh, Hyunwoo [Department of Chemical and Biological Engineering, University of Colorado Boulder, 3415 Colorado Avenue, Boulder, Colorado 80303 (United States); Materials Science and Engineering Program and Department of Nanoengineering, University of California, 9500 Gilman Drive, La Jolla, San Diego, California 92093 (United States); Cha, Jennifer N. [Department of Chemical and Biological Engineering, University of Colorado Boulder, 3415 Colorado Avenue, Boulder, Colorado 80303 (United States); Materials Science and Engineering Program and Department of Nanoengineering, University of California, 9500 Gilman Drive, La Jolla, San Diego, California 92093 (United States); Materials Science and Engineering, University of Colorado Boulder, 3415 Colorado Avenue, Boulder, Colorado 80303 (United States); Nagpal, Prashant, E-mail: pnagpal@colorado.edu [Department of Chemical and Biological Engineering, University of Colorado Boulder, 3415 Colorado Avenue, Boulder, Colorado 80303 (United States); Materials Science and Engineering, University of Colorado Boulder, 3415 Colorado Avenue, Boulder, Colorado 80303 (United States); BioFrontiers Institute, University of Colorado Boulder, 3415 Colorado Avenue, Boulder, Colorado 80303 (United States); Renewable and Sustainable Energy Institute, University of Colorado Boulder, 2445 Kittredge Loop, Boulder, Colorado 80309 (United States)

2015-02-23

Quantum dot (QD), or semiconductor nanocrystal, thin films are being explored for making solution-processable devices due to their size- and shape-tunable bandgap and discrete higher energy electronic states. While DNA has been extensively used for the self-assembly of nanocrystals, it has not been investigated for the simultaneous conduction of multiple energy charges or excitons via exciton shelves (ES) formed in QD-DNA nano-bioelectronic thin films. Here, we present studies on charge conduction through exciton shelves, which are formed via chemically coupled QDs and DNA, between electronic states of the QDs and the HOMO-LUMO levels in the complementary DNA nucleobases. While several challenges need to be addressed in optimizing the formation of devices using QD-DNA thin films, a higher charge collection efficiency for hot-carriers and our detailed investigations of charge transport mechanism in these thin films highlight their potential for applications in nano-bioelectronic devices and biological transducers.

Charge transport through exciton shelves in cadmium chalcogenide quantum dot-DNA nano-bioelectronic thin films

International Nuclear Information System (INIS)

Goodman, Samuel M.; Singh, Vivek; Noh, Hyunwoo; Cha, Jennifer N.; Nagpal, Prashant

2015-01-01

Quantum dot (QD), or semiconductor nanocrystal, thin films are being explored for making solution-processable devices due to their size- and shape-tunable bandgap and discrete higher energy electronic states. While DNA has been extensively used for the self-assembly of nanocrystals, it has not been investigated for the simultaneous conduction of multiple energy charges or excitons via exciton shelves (ES) formed in QD-DNA nano-bioelectronic thin films. Here, we present studies on charge conduction through exciton shelves, which are formed via chemically coupled QDs and DNA, between electronic states of the QDs and the HOMO-LUMO levels in the complementary DNA nucleobases. While several challenges need to be addressed in optimizing the formation of devices using QD-DNA thin films, a higher charge collection efficiency for hot-carriers and our detailed investigations of charge transport mechanism in these thin films highlight their potential for applications in nano-bioelectronic devices and biological transducers

Brillouin gain enhancement in nano-scale photonic waveguide

Science.gov (United States)

Nouri Jouybari, Soodabeh

2018-05-01

The enhancement of stimulated Brillouin scattering in nano-scale waveguides has a great contribution in the improvement of the photonic devices technology. The key factors in Brillouin gain are the electrostriction force and radiation pressure generated by optical waves in the waveguide. In this article, we have proposed a new scheme of nano-scale waveguide in which the Brillouin gain is considerably improved compared to the previously-reported schemes. The role of radiation pressure in the Brillouin gain was much higher than the role of the electrostriction force. The Brillouin gain strongly depends on the structural parameters of the waveguide and the maximum value of 12127 W-1 m-1 is obtained for the Brillouin gain.

Evaporation characteristics of a hydrophilic surface with micro-scale and/or nano-scale structures fabricated by sandblasting and aluminum anodization

International Nuclear Information System (INIS)

Kim, Hyungmo; Kim, Joonwon

2010-01-01

This paper presents the results of evaporation experiments using water droplets on aluminum sheets that were either smooth or had surface structures at the micro-scale, at the nano-scale or at both micro- and nano-scales (dual-scale). The smooth surface was a polished aluminum sheet; the surface with micro-scale structures was obtained by sandblasting; the surface with nano-scale structures was obtained using conventional aluminum anodization and the surface with dual-scale structures was prepared using sandblasting and anodization sequentially. The wetting properties and evaporation rates were measured for each surface. The evaporation rates were affected by their static and dynamic wetting properties. Evaporation on the surface with dual-scale structures was fastest and the evaporation rate was analyzed quantitatively.

Nano-scaled iron-carbon precipitates in HSLC and HSLA steels

Institute of Scientific and Technical Information of China (English)

2007-01-01

This paper studies the composition, quantity and particle size distribution of nano-scaled precipitates with size less than 20 nm in high strength low carbon (HSLC) steel and their effects on mechanical properties of HSLC steel by means of mass balance calculation of nano-scaled precipitates measured by chemical phase analysis plus SAXS method, high-resolution TEM analysis and thermodynamics calculation, as well as temper rapid cooling treatment of ZJ330. It is found that there existed a large quantity of nano-scaled iron-carbon precipitates with size less than 18 nm in low carbon steel produced by CSP and they are mainly Fe-O-C and Fe-Ti-O-C precipitates formed below temperature A1. These precipitates have ob- vious precipitation strengthening effect on HSLC steel and this may be regarded as one of the main reasons why HSLC steel has higher strength. There also existed a lot of iron-carbon precipitates with size less than 36 nm in HSLA steels.

Nano-scaled iron-carbon precipitates in HSLC and HSLA steels

Institute of Scientific and Technical Information of China (English)

FU Jie; WU HuaJie; LIU YangChun; KANG YongLin

2007-01-01

This paper studies the composition, quantity and particle size distribution of nano-scaled precipitates with size less than 20 nm in high strength Iow carbon (HSLC) steel and their effects on mechanical properties of HSLC steel by means of mass balance calculation of nano-scaled precipitates measured by chemical phase analysis plus SAXS method, high-resolution TEM analysis and thermodynamics calculation, as well as temper rapid cooling treatment of ZJ330. It is found that there existed a large quantity of nano-scaled iron-carbon precipitates with size less than 18 nm in Iow carbon steel produced by CSP and they are mainly Fe-O-C and Fe-Ti-O-C precipitates formed below temperature A1. These precipitates have obvious precipitation strengthening effect on HSLC steel and this may be regarded as one of the main reasons why HSLC steel has higher strength. There also existed a lot of iron-carbon precipitates with size less than 36 nm in HSLA steels.

Nano-scale processes behind ion-beam cancer therapy

Science.gov (United States)

Surdutovich, Eugene; Garcia, Gustavo; Mason, Nigel; Solov'yov, Andrey V.

2016-04-01

This topical issue collates a series of papers based on new data reported at the third Nano-IBCT Conference of the COST Action MP1002: Nanoscale Insights into Ion Beam Cancer Therapy, held in Boppard, Germany, from October 27th to October 31st, 2014. The Nano-IBCT COST Action was launched in December 2010 and brought together more than 300 experts from different disciplines (physics, chemistry, biology) with specialists in radiation damage of biological matter from hadron-therapy centres, and medical institutions. This meeting followed the first and the second conferences of the Action held in October 2011 in Caen, France and in May 2013 in Sopot, Poland respectively. This conference series provided a focus for the European research community and has highlighted the pioneering research into the fundamental processes underpinning ion beam cancer therapy. Contribution to the Topical Issue "COST Action Nano-IBCT: Nano-scale Processes Behind Ion-Beam Cancer Therapy", edited by Andrey V. Solov'yov, Nigel Mason, Gustavo Garcia and Eugene Surdutovich.

Close encounters with DNA

Science.gov (United States)

Maffeo, C.; Yoo, J.; Comer, J.; Wells, D. B.; Luan, B.; Aksimentiev, A.

2014-01-01

Over the past ten years, the all-atom molecular dynamics method has grown in the scale of both systems and processes amenable to it and in its ability to make quantitative predictions about the behavior of experimental systems. The field of computational DNA research is no exception, witnessing a dramatic increase in the size of systems simulated with atomic resolution, the duration of individual simulations and the realism of the simulation outcomes. In this topical review, we describe the hallmark physical properties of DNA from the perspective of all-atom simulations. We demonstrate the amazing ability of such simulations to reveal the microscopic physical origins of experimentally observed phenomena and we review the frustrating limitations associated with imperfections of present atomic force fields and inadequate sampling. The review is focused on the following four physical properties of DNA: effective electric charge, response to an external mechanical force, interaction with other DNA molecules and behavior in an external electric field. PMID:25238560

Close encounters with DNA.

Science.gov (United States)

Maffeo, C; Yoo, J; Comer, J; Wells, D B; Luan, B; Aksimentiev, A

2014-10-15

Over the past ten years, the all-atom molecular dynamics method has grown in the scale of both systems and processes amenable to it and in its ability to make quantitative predictions about the behavior of experimental systems. The field of computational DNA research is no exception, witnessing a dramatic increase in the size of systems simulated with atomic resolution, the duration of individual simulations and the realism of the simulation outcomes. In this topical review, we describe the hallmark physical properties of DNA from the perspective of all-atom simulations. We demonstrate the amazing ability of such simulations to reveal the microscopic physical origins of experimentally observed phenomena. We also discuss the frustrating limitations associated with imperfections of present atomic force fields and inadequate sampling. The review is focused on the following four physical properties of DNA: effective electric charge, response to an external mechanical force, interaction with other DNA molecules and behavior in an external electric field.

Chip-Oriented Fluorimeter Design and Detection System Development for DNA Quantification in Nano-Liter Volumes

Directory of Open Access Journals (Sweden)

Da-Sheng Lee

2009-12-01

Full Text Available The chip-based polymerase chain reaction (PCR system has been developed in recent years to achieve DNA quantification. Using a microstructure and miniature chip, the volume consumption for a PCR can be reduced to a nano-liter. With high speed cycling and a low reaction volume, the time consumption of one PCR cycle performed on a chip can be reduced. However, most of the presented prototypes employ commercial fluorimeters which are not optimized for fluorescence detection of such a small quantity sample. This limits the performance of DNA quantification, especially low experiment reproducibility. This study discusses the concept of a chip-oriented fluorimeter design. Using the analytical model, the current study analyzes the sensitivity and dynamic range of the fluorimeter to fit the requirements for detecting fluorescence in nano-liter volumes. Through the optimized processes, a real-time PCR on a chip system with only one nano-liter volume test sample is as sensitive as the commercial real-time PCR machine using the sample with twenty micro-liter volumes. The signal to noise (S/N ratio of a chip system for DNA quantification with hepatitis B virus (HBV plasmid samples is 3 dB higher. DNA quantification by the miniature chip shows higher reproducibility compared to the commercial machine with respect to samples of initial concentrations from 103 to 105 copies per reaction.

Synthesis, fabrication, and spectroscopy of nano-scale photonic noble metal materials

Science.gov (United States)

Egusa, Shunji

Nanometer is an interesting scale for physicists, chemists, and materials scientists, in a sense that it lies between the macroscopic and the atomic scales. In this regime, materials exhibit distinct physical and chemical properties that are clearly different from those of atoms or macroscopic bulk. This thesis is concerned about both physics and chemistry of noble metal nano-structures. Novel chemical syntheses and physical fabrications of various noble metal nano-structures, and the development of spectroscopic techniques for nano-structures are presented. Scanning microscopy/spectroscopy techniques inherently perturbs the true optical responses of the nano-structures. However, by using scanning tunneling microscope (STM) tip as the nanometer-confined excitation source of surface plasmons in the samples, and subsequently collecting the signals in the Fourier space, it is shown that the tip-perturbed part of the signals can be deconvoluted. As a result, the collected signal in this approach is the pure response of the sample. Coherent light is employed to study the optical response of nano-structures, in order to avoid complication from tip-perturbation as discussed above. White-light super-continuum excites the nano-structure, the monolayer of Au nanoparticles self-assembled on silicon nitride membrane substrates. The coherent excitation reveals asymmetric surface plasmon resonance in the nano-structures. One of the most important issues in nano-scale science is to gain control over the shape, size, and assembly of nanoparticles. A novel method is developed to chemically synthesize ligand-passivated atomic noble metal clusters in solution phase. The method, named thermal decomposition method, enables facile yet robust synthesis of fluorescent atomic clusters. Thus synthesized atomic clusters are very stable, and show behaviors of quantum dots. A novel and versatile approach for creation of nanoparticle arrays is developed. This method is different from the

Intelligent Design of Nano-Scale Molecular Imaging Agents

Directory of Open Access Journals (Sweden)

Takeaki Ozawa

2012-12-01

Full Text Available Visual representation and quantification of biological processes at the cellular and subcellular levels within living subjects are gaining great interest in life science to address frontier issues in pathology and physiology. As intact living subjects do not emit any optical signature, visual representation usually exploits nano-scale imaging agents as the source of image contrast. Many imaging agents have been developed for this purpose, some of which exert nonspecific, passive, and physical interaction with a target. Current research interest in molecular imaging has mainly shifted to fabrication of smartly integrated, specific, and versatile agents that emit fluorescence or luminescence as an optical readout. These agents include luminescent quantum dots (QDs, biofunctional antibodies, and multifunctional nanoparticles. Furthermore, genetically encoded nano-imaging agents embedding fluorescent proteins or luciferases are now gaining popularity. These agents are generated by integrative design of the components, such as luciferase, flexible linker, and receptor to exert a specific on–off switching in the complex context of living subjects. In the present review, we provide an overview of the basic concepts, smart design, and practical contribution of recent nano-scale imaging agents, especially with respect to genetically encoded imaging agents.

Computational applications of DNA physical scales

DEFF Research Database (Denmark)

Baldi, Pierre; Chauvin, Yves; Brunak, Søren

1998-01-01

that these scales provide an alternative or complementary compact representation of DNA sequences. As an example we construct a strand invariant representation of DNA sequences. The scales can also be used to analyze and discover new DNA structural patterns, especially in combinations with hidden Markov models......The authors study from a computational standpoint several different physical scales associated with structural features of DNA sequences, including dinucleotide scales such as base stacking energy and propellor twist, and trinucleotide scales such as bendability and nucleosome positioning. We show...

Computational applications of DNA structural scales

DEFF Research Database (Denmark)

Baldi, P.; Chauvin, Y.; Brunak, Søren

1998-01-01

that these scales provide an alternative or complementary compact representation of DNA sequences. As an example, we construct a strand-invariant representation of DNA sequences. The scales can also be used to analyze and discover new DNA structural patterns, especially in combination with hidden Markov models......Studies several different physical scales associated with the structural features of DNA sequences from a computational standpoint, including dinucleotide scales, such as base stacking energy and propeller twist, and trinucleotide scales, such as bendability and nucleosome positioning. We show...

Self-Assembly of Large-Scale Shape-Controlled DNA Nano-Structures

Science.gov (United States)

2014-12-16

for single-molecule imaging. Nano Lett. 11, 657-660 (2011). 46. Dang, X. N. et at. Virus -templated self-assembled single-walled carbon nanotubes for...email: alik(a)rics.bwh.harvard edu). NATURE C0,M.MUN! CAT !0N5 14:2275 I DOI: 10.1038/ncomm53275 | wwwnature.com/naturecommunications 1 @ 2013 Macmillan...prevent non-specific binding between hydrogel and microtube, the inside surface of microtube was treated with a corona treater (BD-20AC from Electro

The mechanical properties modeling of nano-scale materials by molecular dynamics

NARCIS (Netherlands)

Yuan, C.; Driel, W.D. van; Poelma, R.; Zhang, G.Q.

2012-01-01

We propose a molecular modeling strategy which is capable of mod-eling the mechanical properties on nano-scale low-dielectric (low-k) materials. Such modeling strategy has been also validated by the bulking force of carbon nano tube (CNT). This modeling framework consists of model generation method,

A Quick-responsive DNA Nanotechnology Device for Bio-molecular Homeostasis Regulation.

Science.gov (United States)

Wu, Songlin; Wang, Pei; Xiao, Chen; Li, Zheng; Yang, Bing; Fu, Jieyang; Chen, Jing; Wan, Neng; Ma, Cong; Li, Maoteng; Yang, Xiangliang; Zhan, Yi

2016-08-10

Physiological processes such as metabolism, cell apoptosis and immune responses, must be strictly regulated to maintain their homeostasis and achieve their normal physiological functions. The speed with which bio-molecular homeostatic regulation occurs directly determines the ability of an organism to adapt to conditional changes. To produce a quick-responsive regulatory system that can be easily utilized for various types of homeostasis, a device called nano-fingers that facilitates the regulation of physiological processes was constructed using DNA origami nanotechnology. This nano-fingers device functioned in linked open and closed phases using two types of DNA tweezers, which were covalently coupled with aptamers that captured specific molecules when the tweezer arms were sufficiently close. Via this specific interaction mechanism, certain physiological processes could be simultaneously regulated from two directions by capturing one biofactor and releasing the other to enhance the regulatory capacity of the device. To validate the universal application of this device, regulation of the homeostasis of the blood coagulant thrombin was attempted using the nano-fingers device. It was successfully demonstrated that this nano-fingers device achieved coagulation buffering upon the input of fuel DNA. This nano-device could also be utilized to regulate the homeostasis of other types of bio-molecules.

Combustion synthesis of CaSc2O4:Ce3+ nano-phosphors in a closed system

International Nuclear Information System (INIS)

Peng Wenfang; Zou Shaoyu; Liu Guanxi; Xiao Quanlan; Zhang Rui; Xie Lijuan; Cao Liwei; Meng Jianxin; Liu Yingliang

2011-01-01

Highlights: → CaSc 2 O 4 :Ce 3+ nano-phosphors can be prepared by a single-step combustion method. → The ignition temperature is the lowest in the combustion synthesis of Ce 3+ /Eu 2+ doped phosphors. → The as-prepared nano-phosphors give a uniform particle size in the range of 15-20 nm and have highly dispersity and fluorescence intensity. → It is a convenient method for preparation of monodispersed oxide nano-phosphors, especially those being sensitive to air at high temperature. - Abstract: The CaSc 2 O 4 :Ce 3+ nano-phosphors were successfully prepared by a single-step combustion method at an ignition temperature as low as 200 deg. C in a closed autoclave using glycine as a fuel and PEG4000 as a dispersant. The samples were characterized by X-ray diffraction (XRD), photoluminescence (PL) spectroscopy, scanning electron microscopy (SEM) and transmission electron microscope (TEM). The results revealed that CaSc 2 O 4 :Ce 3+ nano-phosphors can be conveniently prepared at an ignition temperature as low as 200 deg. C, which was much lower than that in the ordinary combustion methods. The optimized ignition temperature was 220 deg. C. The CaSc 2 O 4 :Ce 3+ nano-phosphors give a uniform particle size in the range of 15-20 nm. The low ignition temperature and the addition of PEG4000 dispersant play important roles in the formation of small sized nanoparticles. The as-prepared nano-phosphors were incompact aggregates, but highly dispersed nano-phosphors can be obtained after further ultrasonic treatment. The CaSc 2 O 4 :Ce 3+ nano-phosphors give satisfactory luminescence characteristic benefiting from the closed circumstance, in which cerium atoms can be isolated from the oxidizing atmosphere and non-fluorescent Ce 4+ ions can be ruled out. The present highly dispersed CaSc 2 O 4 :Ce 3+ nano-phosphors with efficient fluorescence are promising in the field of biological labeling, and the present low temperature combustion method is facile and convenient and can

Development of a real-time closed-loop micro-/nano-positioning system embedded with a capacitive sensor

International Nuclear Information System (INIS)

Shiou, Fang-Jung; Chiang, Chia-Jui; Liou, Ke-Jhen; Liao, Shu-Chung; Chen, Chao-Jung; Liou, Huay-Chung

2010-01-01

The hysteresis and nonlinearity of the PZT is an actual problem in the piezo-driven micro-/nano-positioning stage, especially for the open-loop positioning stage. The study presents the development of an NI cRIO9074-based real-time closed-loop micro-/nano-positioning system, to overcome the problem of the hysteresis and nonlinearity of a PZT and to increase the positioning speed of the positioning stage. The developed system mainly consists of a piezoelectric actuator, a bridge-type hinge mechanism for displacement magnification, a micro-/nano-positioning stage body, a capacitive sensor system, an NI cRIO9074 real-time control unit with FPGA chip and a PC. After executing the optimization analysis of the displacement, stress and the frequency, using the ANSYS software, the dimensions of the stage body have been designed and determined. A set of software written with the LabView programming language was developed to construct the real-time PID closed-loop control of the developed positioning system. Based on the test results, the designed closed-loop micro-/nano-positioning system was capable of precision positioning within the travel of 119.08 µm with maximum stage tilting angle at 25 µrad. The steady-state positioning deviation of the stage is about ±2 nm in the step-positioning test. In the transient slope-tracing test at a tracing speed of 5 µm s −1 , an error of about ±100 nm is observed

Alternative chemical-based synthesis routes and characterization of nano-scale particles

International Nuclear Information System (INIS)

Brocchi, E.A.; Motta, M.S.; Solorzano, I.G.; Jena, P.K.; Moura, F.J.

2004-01-01

Different nano-scale particles have been synthesized by alternative routes: nitrates dehydratation and oxide, or co-formed oxides, reduction by hydrogen. Chemical-based synthesis routes are described and thermodynamics studies and kinetics data are presented to support the feasibility for obtaining single-phase oxides and co-formed two-phase oxides. In addition, the reduction reaction has been applied to successfully produce metal/ceramic nanocomposites. Structural characterization has been carried out by means of X-ray diffraction and, more extensively, transmission electron microscopy operating in conventional diffraction contrast mode (CTEM) and high-resolution mode (HRTEM). Nano-scale size distribution of oxide particles is well demonstrated together with their defect-free structure in the lower range, around 20 nm, size. Structural features related to the synthesized nano-composites are also presented

Writing to and reading from a nano-scale crossbar memory based on memristors

International Nuclear Information System (INIS)

Vontobel, Pascal O; Robinett, Warren; Kuekes, Philip J; Stewart, Duncan R; Straznicky, Joseph; Stanley Williams, R

2009-01-01

We present a design study for a nano-scale crossbar memory system that uses memristors with symmetrical but highly nonlinear current-voltage characteristics as memory elements. The memory is non-volatile since the memristors retain their state when un-powered. In order to address the nano-wires that make up this nano-scale crossbar, we use two coded demultiplexers implemented using mixed-scale crossbars (in which CMOS-wires cross nano-wires and in which the crosspoint junctions have one-time configurable memristors). This memory system does not utilize the kind of devices (diodes or transistors) that are normally used to isolate the memory cell being written to and read from in conventional memories. Instead, special techniques are introduced to perform the writing and the reading operation reliably by taking advantage of the nonlinearity of the type of memristors used. After discussing both writing and reading strategies for our memory system in general, we focus on a 64 x 64 memory array and present simulation results that show the feasibility of these writing and reading procedures. Besides simulating the case where all device parameters assume exactly their nominal value, we also simulate the much more realistic case where the device parameters stray around their nominal value: we observe a degradation in margins, but writing and reading is still feasible. These simulation results are based on a device model for memristors derived from measurements of fabricated devices in nano-scale crossbars using Pt and Ti nano-wires and using oxygen-depleted TiO 2 as the switching material.

Detection of HBV Covalently Closed Circular DNA

Directory of Open Access Journals (Sweden)

Xiaoling Li

2017-06-01

Full Text Available Chronic hepatitis B virus (HBV infection affects approximately 240 million people worldwide and remains a serious public health concern because its complete cure is impossible with current treatments. Covalently closed circular DNA (cccDNA in the nucleus of infected cells cannot be eliminated by present therapeutics and may result in persistence and relapse. Drug development targeting cccDNA formation and maintenance is hindered by the lack of efficient cccDNA models and reliable cccDNA detection methods. Southern blotting is regarded as the gold standard for quantitative cccDNA detection, but it is complicated and not suitable for high-throughput drug screening, so more sensitive and simple methods, including polymerase chain reaction (PCR-based methods, Invader assays, in situ hybridization and surrogates, have been developed for cccDNA detection. However, most methods are not reliable enough, and there are no unified standards for these approaches. This review will summarize available methods for cccDNA detection. It is hoped that more robust methods for cccDNA monitoring will be developed and that standard operation procedures for routine cccDNA detection in scientific research and clinical monitoring will be established.

Nano-funnels as electro-osmotic ``tweezers and pistons''

Science.gov (United States)

Wang, Yanqian; Panyukov, Sergey; Zhou, Jinsheng; Menard, Laurent D.; Ramsey, J. Michael; Rubinstien, Michael

2014-03-01

An electric field is used to force a DNA molecule into a nano-channel by compensating the free energy penalty that results from the reduced conformational entropy of the confined macromolecule. Narrow nano-channels require high critical electric fields to achieve DNA translocation, leading to short dwell times of DNA in these channels. We demonstrate that nano-funnels integrated with nano-channels reduce the free energy barrier and lower the critical electric field required for DNA translocation. A focused electric field within the funnel increases the electric force on the DNA, compresses the molecule, and increases the osmotic pressure at the nano-channel entrance. This ``electro-osmotic piston'' forces the molecule into the nano-channel at lower electric fields than those observed without the funnel. Appropirately designed nano-funnels can also function as tweezers that allow manipulation of the position of the DNA molecule. The predictions of our theory describing double-stranded DNA behavior in nano-funnel - nano-channel devices are consistent with experimental results. Thanks for the financial support from NSF (DMR-1309892, DMR-1121107, DMR-1122483), NIH (1-P50-HL107168, 1-P01-HL108808-01A1, R01HG02647), NHGRI and CF Foundation.

Production of ultra-thin nano-scaled graphene platelets from meso-carbon micro-beads

Science.gov (United States)

Zhamu, Aruna; Guo, Jiusheng; Jang, Bor Z

2014-11-11

A method of producing nano-scaled graphene platelets (NGPs) having an average thickness no greater than 50 nm, typically less than 2 nm, and, in many cases, no greater than 1 nm. The method comprises (a) intercalating a supply of meso-carbon microbeads (MCMBs) to produce intercalated MCMBs; and (b) exfoliating the intercalated MCMBs at a temperature and a pressure for a sufficient period of time to produce the desired NGPs. Optionally, the exfoliated product may be subjected to a mechanical shearing treatment, such as air milling, air jet milling, ball milling, pressurized fluid milling, rotating-blade grinding, or ultrasonicating. The NGPs are excellent reinforcement fillers for a range of matrix materials to produce nanocomposites. Nano-scaled graphene platelets are much lower-cost alternatives to carbon nano-tubes or carbon nano-fibers.

Nano-Scale Interpenetrating Phase Composites (IPC S) for Industrial and Vehicle Applications

Energy Technology Data Exchange (ETDEWEB)

Hemrick, James Gordon [ORNL; Hu, Michael Z. [ORNL

2010-06-01

A one-year project was completed at Oak Ridge National Laboratory (ORNL) to explore the technical and economic feasibility of producing nano-scale Interpenetrating Phase Composite (IPC) components of a usable size for actual testing/implementation in a real applications such as high wear/corrosion resistant refractory shapes for industrial applications, lightweight vehicle braking system components, or lower cost/higher performance military body and vehicle armor. Nano-scale IPC s with improved mechanical, electrical, and thermal properties have previously been demonstrated at the lab scale, but have been limited in size. The work performed under this project was focused on investigating the ability to take the current traditional lab scale processes to a manufacturing scale through scaling of these processes or through the utilization of an alternative high-temperature process.

Linear arrangement of nano-scale magnetic particles formed in Cu-Fe-Ni alloys

Energy Technology Data Exchange (ETDEWEB)

Kang, Sung, E-mail: k3201s@hotmail.co [Department of Materials Engineering (SEISAN), Yokohama National University, 79-5 Tokiwadai, Hodogayaku, Yokohama, 240-8501 (Japan); Takeda, Mahoto [Department of Materials Engineering (SEISAN), Yokohama National University, 79-5 Tokiwadai, Hodogayaku, Yokohama, 240-8501 (Japan); Takeguchi, Masaki [Advanced Electron Microscopy Group, National Institute for Materials Science (NIMS), Sakura 3-13, Tsukuba, 305-0047 (Japan); Bae, Dong-Sik [School of Nano and Advanced Materials Engineering, Changwon National University, Gyeongnam, 641-773 (Korea, Republic of)

2010-04-30

The structural evolution of nano-scale magnetic particles formed in Cu-Fe-Ni alloys on isothermal annealing at 878 K has been investigated by means of transmission electron microscopy (TEM), electron dispersive X-ray spectroscopy (EDS), electron energy-loss spectroscopy (EELS) and field-emission scanning electron microscopy (FE-SEM). Phase decomposition of Cu-Fe-Ni occurred after an as-quenched specimen received a short anneal, and nano-scale magnetic particles were formed randomly in the Cu-rich matrix. A striking feature that two or more nano-scale particles with a cubic shape were aligned linearly along <1,0,0> directions was observed, and the trend was more pronounced at later stages of the precipitation. Large numbers of <1,0,0> linear chains of precipitates extended in three dimensions in late stages of annealing.

Magnified fluorescence detection of silver(I) ion in aqueous solutions by using nano-graphite-DNA hybrid and DNase I.

Science.gov (United States)

Wei, Yin; Li, Bianmiao; Wang, Xu; Duan, Yixiang

2014-08-15

This paper describes a novel approach utilizing nano-graphite-DNA hybrid and DNase I for the amplified detection of silver(I) ion in aqueous solutions for the first time. Nano-graphite can effectively quench the fluorescence of dye-labeled cytosine-rich single-stranded DNA due to its strong π-π stacking interactions; however, in the presence of Ag(+), C-Ag(+)-C coordination induces the probe to fold into a hairpin structure, which does not adsorb on the surface of nano-graphite and thus retains the dye fluorescence. Meanwhile, the hairpin structure can be cleaved by DNase I, and in such case Ag(+) is delivered from the complex. The released Ag(+) then binds other dye-labeled single-stranded DNA on the nano-graphite surface, and touches off another target recycling, resulting in the successive release of dye-labeled single-stranded DNA from the nano-graphite, which leads to significant amplification of the signal. The present magnification sensing system exhibits high sensitivity toward Ag(+) with a limit of detection of 0.3nM (S/N=3), which is much lower than the standard for Ag(+) in drinking water recommended by the Environmental Protection Agency (EPA). The selectivity of the sensor for Ag(+) against other biologically and environmentally related metal ions is outstanding due to the high specificity of C-Ag(+)-C formation. Moreover, the sensing system is used for the determination of Ag(+) in river water samples with satisfying results. The proposed assay is simple, cost-effective, and might open the door for the development of new assays for other metal ions or biomolecules. Copyright © 2014 Elsevier B.V. All rights reserved.

Enhanced immune response and protective effects of nano-chitosan-based DNA vaccine encoding T cell epitopes of Esat-6 and FL against Mycobacterium tuberculosis infection.

Directory of Open Access Journals (Sweden)

Ganzhu Feng

Full Text Available Development of a novel and effective vaccine against Mycobacterium tuberculosis (M.tb is a challenging for preventing TB infection. In this study, a novel nanoparticle-based recombinant DNA vaccine was developed, which contains Esat-6 three T cell epitopes (Esat-6/3e and fms-like tyrosine kinase 3 ligand (FL genes (termed Esat-6/3e-FL, and was enveloped with chitosan (CS nanoparticles (nano-chitosan. The immunologic and protective efficacy of the nano-chitosan-based DNA vaccine (termed nano-Esat-6/3e-FL was assessed in C57BL/6 mice after intramuscular prime vaccination with the plasmids DNA and nasal boost with the Esat-6/3e peptides. The results showed that the immunized mice remarkably elicited enhanced T cell responses and protection against M.tb H37Rv challenge. These findings indicate that the nano-chitosan can significantly elevate the immunologic and protective effects of the DNA vaccine, and the nano-Esat-6/3e-FL is a useful vaccine for preventing M.tb infection in mice.

Effect of TMAH Etching Duration on the Formation of Silicon Nano wire Transistor Patterned by AFM Nano lithography

International Nuclear Information System (INIS)

Hutagalung, S.D.; Lew, K.C.

2012-01-01

Atomic force microscopy (AFM) lithography was applied to produce nano scale pattern for silicon nano wire transistor fabrication. This technique takes advantage of imaging facility of AFM and the ability of probe movement controlling over the sample surface to create nano patterns. A conductive AFM tip was used to grow the silicon oxide nano patterns on silicon on insulator (SOI) wafer. The applied tip-sample voltage and writing speed were well controlled in order to form pre-designed silicon oxide nano wire transistor structures. The effect of tetra methyl ammonium hydroxide (TMAH) etching duration on the oxide covered silicon nano wire transistor structure has been investigated. A completed silicon nano wire transistor was obtained by removing the oxide layer via hydrofluoric acid etching process. The fabricated silicon nano wire transistor consists of a silicon nano wire that acts as a channel with source and drain pads. A lateral gate pad with a nano wire head was fabricated very close to the channel in the formation of transistor structures. (author)

Close sequence identity between ribosomal DNA episomes of the ...

Indian Academy of Sciences (India)

Unknown

The restriction map of the E. dispar rDNA circle showed close simi- larity to EhR1 .... for 30 cycles in a DNA Thermal cycler (MJ Research,. USA). 3. .... by asterisk. The gaps show the variation between E. dispar and E. histolytica sequences.

Nano-scaled semiconductor devices physics, modelling, characterisation, and societal impact

CERN Document Server

Gutiérrez-D, Edmundo A

2016-01-01

This book describes methods for the characterisation, modelling, and simulation prediction of these second order effects in order to optimise performance, energy efficiency and new uses of nano-scaled semiconductor devices.

Investigation on the special Smith-Purcell radiation from a nano-scale rectangular metallic grating

International Nuclear Information System (INIS)

Li, Weiwei; Liu, Weihao; Jia, Qika

2016-01-01

The special Smith-Purcell radiation (S-SPR), which is from the radiating eigen modes of a grating, has remarkable higher intensity than the ordinary Smith-Purcell radiation. Yet in previous studies, the gratings were treated as perfect conductor without considering the surface plasmon polaritons (SPPs) which are of significance for the nano-scale gratings especially in the optical region. In present paper, the rigorous theoretical investigations on the S-SPR from a nano-grating with SPPs taken into consideration are carried out. The dispersion relations and radiation characteristics are obtained, and the results are verified by simulations. According to the analyses, the tunable light radiation can be achieved by the S-SPR from a nano-grating, which offers a new prospect for developing the nano-scale light sources.

Annealing helicase HARP closes RPA-stabilized DNA bubbles non-processively.

Science.gov (United States)

Burnham, Daniel R; Nijholt, Bas; De Vlaminck, Iwijn; Quan, Jinhua; Yusufzai, Timur; Dekker, Cees

2017-05-05

We investigate the mechanistic nature of the Snf2 family protein HARP, mutations of which are responsible for Schimke immuno-osseous dysplasia. Using a single-molecule magnetic tweezers assay, we construct RPA-stabilized DNA bubbles within torsionally constrained DNA to investigate the annealing action of HARP on a physiologically relevant substrate. We find that HARP closes RPA-stabilized bubbles in a slow reaction, taking on the order of tens of minutes for ∼600 bp of DNA to be re-annealed. The data indicate that DNA re-anneals through the removal of RPA, which is observed as clear steps in the bubble-closing traces. The dependence of the closing rate on both ionic strength and HARP concentration indicates that removal of RPA occurs via an association-dissociation mechanism where HARP does not remain associated with the DNA. The enzyme exhibits classical Michaelis-Menten kinetics and acts cooperatively with a Hill coefficient of 3 ± 1. Our work also allows the determination of some important features of RPA-bubble structures at low supercoiling, including the existence of multiple bubbles and that RPA molecules are mis-registered on the two strands. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

Book Review: Nano physics & Nano technology

Directory of Open Access Journals (Sweden)

Abdolkhaled Zaree

2012-12-01

Full Text Available During last decades, there are a lot of emphases on studying material behavior in atomic scale. In most scientific and engineering fields, one can see the effect of nanotechnology. The aim of nanoscience is to design and fabrication of new and applicable materials. Nowadays, Nano is a popular science which chemists, physicist, doctors, engineers, financial managers and environment's fans for creating a good life via nanoscience have a great cooperation with each others. Materials in nano scale such as nanotubes and nanowires have extraordinary properties which by optimization of these properties in nano scale and then develop these properties to macro scale, they've been challenging issues. For instance, materials in nano scale improve mechanical properties of polymers and metallic materials via nano particles and on the other hand by producing a thin film on surfaces improve surface hardening. Besides, nanotechnology is in hi-tech industries such as magnetic devices, surface coating, and biomaterial, material having sensors, polymers, gels, ceramics and intelligent membrane. Nano-carbon tubes are considered intelligent due to the fact that they couple electrochemical and elastic properties simultaneously, hence have greater activation energy density in comparison with other intelligent materials. Studying nanoscience is important because it causes the life to be better. Future Materials and structures will have a lot of outstanding properties. Intelligent machines can repair, recycle and reconstruct themselves. All these features are only possible in nano zone. Nano in engineering science can provide the possibility of making light missiles for exploring space. The reduced weight can be achieved by replacing traditional materials with hybrid nanocomposites.

The Neurologic Assessment in Neuro-Oncology (NANO) Scale as an Assessment Tool for Survival in Patients With Primary Glioblastoma.

Science.gov (United States)

Ung, Timothy H; Ney, Douglas E; Damek, Denise; Rusthoven, Chad G; Youssef, A Samy; Lillehei, Kevin O; Ormond, D Ryan

2018-03-30

The Neurologic Assessment in Neuro-Oncology (NANO) scale is a standardized objective metric designed to measure neurological function in neuro-oncology. Current neuroradiological evaluation guidelines fail to use specific clinical criteria for progression. To determine if the NANO scale was a reliable assessment tool in glioblastoma (GBM) patients and whether it correlated to survival. Our group performed a retrospective review of all patients with newly diagnosed GBM from January 1, 2010, through December 31, 2012, at our institution. We applied the NANO scale, Karnofsky performance score (KPS), Eastern Cooperative Oncology Group (ECOG) scale, Macdonald criteria, and the Response Assessment in Neuro-Oncology (RANO) criteria to patients at the time of diagnosis as well as at 3, 6, and 12 mo. Initial NANO score was correlated with overall survival at time of presentation. NANO progression was correlated with decreased survival in patients at 6 and 12 mo. A decrease in KPS was associated with survival at 3 and 6 mo, an increase in ECOG score was associated only at 3 mo, and radiological evaluation (RANO and Macdonald) was correlated at 3 and 6 mo. Only the NANO scale was associated with patient survival at 1 yr. NANO progression was the only metric that was linked to decreased overall survival when compared to RANO and Macdonald at 6 and 12 mo. The NANO scale is specific to neuro-oncology and can be used to assess patients with glioma. This retrospective analysis demonstrates the usefulness of the NANO scale in glioblastoma.

Protein-material interactions: From micro-to-nano scale

International Nuclear Information System (INIS)

Tsapikouni, Theodora S.; Missirlis, Yannis F.

2008-01-01

The article presents a survey on the significance of protein-material interactions, the mechanisms which control them and the techniques used for their study. Protein-surface interactions play a key role in regenerative medicine, drug delivery, biosensor technology and chromatography, while it is related to various undesired effects such as biofouling and bio-prosthetic malfunction. Although the effects of protein-surface interaction concern the micro-scale, being sometimes obvious even with bare eyes, they derive from biophysical events at the nano-scale. The sequential steps for protein adsorption involve events at the single biomolecule level and the forces driving or inhibiting protein adsorption act at the molecular level too. Following the scaling of protein-surface interactions, various techniques have been developed for their study both in the micro- and nano-scale. Protein labelling with radioisotopes or fluorescent probes, colorimetric assays and the quartz crystal microbalance were the first techniques used to monitor protein adsorption isotherms, while the surface force apparatus was used to measure the interaction forces between protein layers at the micro-scale. Recently, more elaborate techniques like total internal reflection fluorescence (TIRF), Fourier transform infrared spectroscopy (FTIR), surface plasmon resonance, Raman spectroscopy, ellipsometry and time of flight secondary ion mass spectrometry (ToF-SIMS) have been applied for the investigation of protein density, structure or orientation at the interfaces. However, a turning point in the study of protein interactions with the surfaces was the invention and the wide-spread use of atomic force microscopy (AFM) which can both image single protein molecules on surfaces and directly measure the interaction force

Nano-Scale Spatial Assessment of Calcium Distribution in Coccolithophores Using Synchrotron-Based Nano-CT and STXM-NEXAFS

Science.gov (United States)

Sun, Shiyong; Yao, Yanchen; Zou, Xiang; Fan, Shenglan; Zhou, Qing; Dai, Qunwei; Dong, Faqin; Liu, Mingxue; Nie, Xiaoqin; Tan, Daoyong; Li, Shuai

2014-01-01

Calcified coccolithophores generate calcium carbonate scales around their cell surface. In light of predicted climate change and the global carbon cycle, the biomineralization ability of coccoliths has received growing interest. However, the underlying biomineralization mechanism is not yet well understood; the lack of non-invasive characterizing tools to obtain molecular level information involving biogenic processes and biomineral components remain significant challenges. In the present study, synchrotron-based Nano-computed Tomography (Nano-CT) and Scanning Transmission X-ray Microscopy-Near-edge X-ray Absorption Fine Structure Spectromicroscopy (STXM-NEXAFS) techniques were employed to identify Ca spatial distribution and investigate the compositional chemistry and distinctive features of the association between biomacromolecules and mineral components of calcite present in coccoliths. The Nano-CT results show that the coccolith scale vesicle is similar as a continuous single channel. The mature coccoliths were intracellularly distributed and immediately ejected and located at the exterior surface to form a coccoshpere. The NEXAFS spectromicroscopy results of the Ca L edge clearly demonstrate the existence of two levels of gradients spatially, indicating two distinctive forms of Ca in coccoliths: a crystalline-poor layer surrounded by a relatively crystalline-rich layer. The results show that Sr is absorbed by the coccoliths and that Sr/Ca substitution is rather homogeneous within the coccoliths. Our findings indicate that synchrotron-based STXM-NEXAFS and Nano-CT are excellent tools for the study of biominerals and provide information to clarify biomineralization mechanism. PMID:25530614

Single Molecule Nano-Metronome

Science.gov (United States)

Buranachai, Chittanon; McKinney, Sean A.; Ha, Taekjip

2008-01-01

We constructed a DNA-based nano-mechanical device called the nano-metronome. Our device is made by introducing complementary single stranded overhangs at the two arms of the DNA four-way junction. The ticking rates of this stochastic metronome depend on ion concentrations and can be changed by a set of DNA-based switches to deactivate/reactivate the sticky end. Since the device displays clearly distinguishable responses even with a single basepair difference, it may lead to a single molecule sensor of minute sequence differences of a target DNA. PMID:16522050

Nano- and micro-electromechanical systems fundamentals of nano- and microengineering

CERN Document Server

Lyshevski, Sergey Edward

2005-01-01

NANOTECHNOLOGY AND MICROTECHNOLOGY (NANO- AND MICRO- SCIENCE, ENGINEERING AND TECHNOLOGY), AND BEYOND Introduction and Overview: From Micro- to Nano- and Beyond to Stringo-Scale Introductory Definitions to the Subjects Current Developments and Needs for Coherent Revolutionary Developments Societal Challenges and Implications NANO- AND MICROSCALE SYSTEMS, DEVICES, AND STRUCTURES Sizing Features: From Micro- to Nano-, and from Nano- to Stringo-Scale MEMS and NEMS Definitions Introduction to Taxonomy of Nano- and Microsystem Synthesis and Design Introduction to Design and Optimization of Nano- and Microsystems in the Behavioral Domain NANO- AND MICROSYSTEMS: CLASSIFICATION AND CONSIDERATION Biomimetics, Biological Analogies,and Design of NEMS and MEMS Micro- and Nanoelectromechanical Systems: Scaling Laws and Mathematical Modeling MEMS Examples and MEMS Architectures Introduction to Microfabrication and Micromachining FUNDAMENTALS OF MICROFABRICATION AND MEMS FABRICATION TECHNOLOGIES Introducti...

Advances in multiscale modeling of materials behavior: from nano to macro scales

International Nuclear Information System (INIS)

Zbib, Hussein M.

2004-01-01

Full text.The development of micromechanical devices, thin films, nano layered structures and nano composite coating materials, such as those used in microelectronics, transportation, medical diagnostics and implant industries, requires the utilization of materials that possess a high degree of material reliability, structural stability, mechanical strength, high ductility, toughness and resistance to fracture and fatigue. To achieve these properties many of these devices can be constructed from micro/nano structured materials, which often exhibit enhanced mechanical strength and ductility when compared to conventional materials. However, although the promise of such materials has been demonstrated in laboratories, it has not made inroads into commercial manufacturing in the area of structural materials. A primary impediment to bringing these technologies to the market is the inability to scale up from small scale laboratory experiments to manufacturing methods. Our work at WSU has been to develop theories and computational tools, verified by experiments, which are required to understand and design micro and nano structured materials for various structural applications. The results of this work have a major impact on this emerging industry and are being used in many national and international research institutes

Application of exergetic sustainability index to a nano-scale irreversible Brayton cycle operating with ideal Bose and Fermi gasses

Energy Technology Data Exchange (ETDEWEB)

Açıkkalp, Emin, E-mail: eacikkalp@gmail.com [Department of Mechanical and Manufacturing Engineering, Engineering Faculty, Bilecik S.E. University, Bilecik (Turkey); Caner, Necmettin [Department of Chemistry, Faculty of Arts and Sciences, Eskisehir Osmangazi University, Eskisehir (Turkey)

2015-09-25

Highlights: • An irreversible Brayton cycle operating quantum gasses is considered. • Exergetic sustainability index is derived for nano-scale cycles. • Nano-scale effects are considered. • Calculation are conducted for irreversible cycles. • Numerical results are presented and discussed. - Abstract: In this study, a nano-scale irreversible Brayton cycle operating with quantum gasses including Bose and Fermi gasses is researched. Developments in the nano-technology cause searching the nano-scale machines including thermal systems to be unavoidable. Thermodynamic analysis of a nano-scale irreversible Brayton cycle operating with Bose and Fermi gasses was performed (especially using exergetic sustainability index). In addition, thermodynamic analysis involving classical evaluation parameters such as work output, exergy output, entropy generation, energy and exergy efficiencies were conducted. Results are submitted numerically and finally some useful recommendations were conducted. Some important results are: entropy generation and exergetic sustainability index are affected mostly for Bose gas and power output and exergy output are affected mostly for the Fermi gas by x. At the high temperature conditions, work output and entropy generation have high values comparing with other degeneracy conditions.

Single Molecule Nano-Metronome

OpenAIRE

Buranachai, Chittanon; McKinney, Sean A.; Ha, Taekjip

2006-01-01

We constructed a DNA-based nano-mechanical device called the nano-metronome. Our device is made by introducing complementary single stranded overhangs at the two arms of the DNA four-way junction. The ticking rates of this stochastic metronome depend on ion concentrations and can be changed by a set of DNA-based switches to deactivate/reactivate the sticky end. Since the device displays clearly distinguishable responses even with a single basepair difference, it may lead to a single molecule ...

Introduction of Functional Structures in Nano-Scales into Engineering Polymer Films Using Radiation Technique

Energy Technology Data Exchange (ETDEWEB)

Maekawa, Y., E-mail: maekawa.yasunari@jaea.go.jp [Japan Atomic Energy Agency (JAEA), Quantum Beam Science Directorate, High Performance Polymer Group, 1233 Watanuki-Machi, Takasaki, Gunma-ken 370-1292 (Japan)

2010-07-01

Introduction of functional regions in nanometer scale in polymeric films using γ-rays, EB, and ion beams are proposed. Two approaches to build nano-scale functional domains in polymer substrates are proposed: 1) Radiation-induced grafting to transfer nano-scale polymer crystalline structures (morphology), acting as a nano-template, to nano-scale graft polymer regions. The obtained polymers with nano structures can be applied to high performance polymer membranes. 2) Fabrication of nanopores and functional domains in engineering plastic films using ion beams, which deposit the energy in very narrow region of polymer films. Hydrophilic grafting polymers are introduced into hydrophobic fluorinated polymers, cross-linked PTFE (cPTFE) and aromatic hydrocarbon polymer, poly(ether ether ketone (PEEK), which is known to have lamella and crystallite in the polymer films. Then, the hierarchical structures of graft domains are analyzed by a small angle neutron scattering (SANS) experiment. From these analyses, the different structures and the different formation of graft domains were observed in fluorinated and hydrocarbon polymer substrates. the grafted domains in the cPTFE film, working as an ion channel, grew as covering the crystallite and the size of domain seems to be similar to that of crystallite. On the other hand, the PEEK-based PEM has a smaller domain size and it seems to grow independently on the crystallites of PEEK substrate. For nano-fabrication of polymer films using heavy ion beams, the energy distribution in radial direction, which is perpendicular to ion trajectory, is mainly concerned. For penumbra, we re-estimated effective radius of penumbra, in which radiation induced grafting took place, for several different ion beams. We observed the different diameters of the ion channels consisting of graft polymers. The channel sizes were quite in good agreement with the effective penumbra which possess the absorption doses more than 1 kGy. (author)

Introduction of Functional Structures in Nano-Scales into Engineering Polymer Films Using Radiation Technique

International Nuclear Information System (INIS)

Maekawa, Y.

2010-01-01

Introduction of functional regions in nanometer scale in polymeric films using γ-rays, EB, and ion beams are proposed. Two approaches to build nano-scale functional domains in polymer substrates are proposed: 1) Radiation-induced grafting to transfer nano-scale polymer crystalline structures (morphology), acting as a nano-template, to nano-scale graft polymer regions. The obtained polymers with nano structures can be applied to high performance polymer membranes. 2) Fabrication of nanopores and functional domains in engineering plastic films using ion beams, which deposit the energy in very narrow region of polymer films. Hydrophilic grafting polymers are introduced into hydrophobic fluorinated polymers, cross-linked PTFE (cPTFE) and aromatic hydrocarbon polymer, poly(ether ether ketone (PEEK), which is known to have lamella and crystallite in the polymer films. Then, the hierarchical structures of graft domains are analyzed by a small angle neutron scattering (SANS) experiment. From these analyses, the different structures and the different formation of graft domains were observed in fluorinated and hydrocarbon polymer substrates. the grafted domains in the cPTFE film, working as an ion channel, grew as covering the crystallite and the size of domain seems to be similar to that of crystallite. On the other hand, the PEEK-based PEM has a smaller domain size and it seems to grow independently on the crystallites of PEEK substrate. For nano-fabrication of polymer films using heavy ion beams, the energy distribution in radial direction, which is perpendicular to ion trajectory, is mainly concerned. For penumbra, we re-estimated effective radius of penumbra, in which radiation induced grafting took place, for several different ion beams. We observed the different diameters of the ion channels consisting of graft polymers. The channel sizes were quite in good agreement with the effective penumbra which possess the absorption doses more than 1 kGy. (author)

Nano/micro-scale magnetophoretic devices for biomedical applications

International Nuclear Information System (INIS)

Lim, Byeonghwa; Kim, CheolGi; Vavassori, Paolo; Sooryakumar, R

2017-01-01

In recent years there have been tremendous advances in the versatility of magnetic shuttle technology using nano/micro-scale magnets for digital magnetophoresis. While the technology has been used for a wide variety of single-cell manipulation tasks such as selection, capture, transport, encapsulation, transfection, or lysing of magnetically labeled and unlabeled cells, it has also expanded to include parallel actuation and study of multiple bio-entities. The use of nano/micro-patterned magnetic structures that enable remote control of the applied forces has greatly facilitated integration of the technology with microfluidics, thereby fostering applications in the biomedical arena. The basic design and fabrication of various scaled magnets for remote manipulation of individual and multiple beads/cells, and their associated energies and forces that underlie the broad functionalities of this approach, are presented. One of the most useful features enabled by such advanced integrated engineering is the capacity to remotely tune the magnetic field gradient and energy landscape, permitting such multipurpose shuttles to be implemented within lab-on-chip platforms for a wide range of applications at the intersection of cellular biology and biotechnology. (topical review)

Nano/micro-scale magnetophoretic devices for biomedical applications

Science.gov (United States)

Lim, Byeonghwa; Vavassori, Paolo; Sooryakumar, R.; Kim, CheolGi

2017-01-01

In recent years there have been tremendous advances in the versatility of magnetic shuttle technology using nano/micro-scale magnets for digital magnetophoresis. While the technology has been used for a wide variety of single-cell manipulation tasks such as selection, capture, transport, encapsulation, transfection, or lysing of magnetically labeled and unlabeled cells, it has also expanded to include parallel actuation and study of multiple bio-entities. The use of nano/micro-patterned magnetic structures that enable remote control of the applied forces has greatly facilitated integration of the technology with microfluidics, thereby fostering applications in the biomedical arena. The basic design and fabrication of various scaled magnets for remote manipulation of individual and multiple beads/cells, and their associated energies and forces that underlie the broad functionalities of this approach, are presented. One of the most useful features enabled by such advanced integrated engineering is the capacity to remotely tune the magnetic field gradient and energy landscape, permitting such multipurpose shuttles to be implemented within lab-on-chip platforms for a wide range of applications at the intersection of cellular biology and biotechnology.

Gold nano particle decorated graphene core first generation PAMAM dendrimer for label free electrochemical DNA hybridization sensing.

Science.gov (United States)

Jayakumar, K; Rajesh, R; Dharuman, V; Venkatasan, R; Hahn, J H; Pandian, S Karutha

2012-01-15

A novel first generation (G1) poly(amidoamine) dendrimer (PAMAM) with graphene core (GG1PAMAM) was synthesized for the first time. Single layer of GG1PAMAM was immobilized covalently on mercaptopropionic acid (MPA) monolayer on Au transducer. This allows cost effective and easy deposition of single layer graphene on the Au transducer surface than the advanced vacuum techniques used in the literature. Au nano particles (17.5 nm) then decorated the GG1PAMAM and used for electrochemical DNA hybridization sensing. The sensor discriminates selectively and sensitively the complementary double stranded DNA (dsDNA, hybridized), non-complementary DNA (ssDNA, un-hybridized) and single nucleotide polymorphism (SNP) surfaces. Interactions of the MPA, GG1PAMAM and the Au nano particles were characterized by Ultra Violet (UV), Fourier Transform Infrared (FTIR), Raman spectroscopy (RS), Thermo gravimetric analysis (TGA), Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), Cyclic Voltmetric (CV), Impedance spectroscopy (IS) and Differntial Pulse Voltammetry (DPV) techniques. The sensor showed linear range 1×10(-6) to 1×10(-12) M with lowest detection limit 1 pM which is 1000 times lower than G1PAMAM without graphene core. Copyright © 2011 Elsevier B.V. All rights reserved.

Antiviral strategies to eliminate hepatitis B virus covalently closed circular DNA (cccDNA).

Science.gov (United States)

Revill, Peter; Locarnini, Stephen

2016-10-01

It has been over 50 years since the discovery of hepatitis B virus (HBV), yet 240 million people worldwide live with chronic HBV, resulting in up to 800000 deaths per year. A cure is yet to be achieved, due largely to a viral nuclear reservoir of transcriptionally active covalently closed circular DNA (cccDNA). While current antiviral therapies are effective at reducing viral replication, they have no impact on the existing cccDNA reservoir. Identifying mechanisms to either eliminate (complete cure) or inactivate (functional cure) HBV cccDNA are a major focus of HBV research worldwide. This review discusses recent advances in efforts to eliminate and/or regulate cccDNA, as well as future directions that may be considered in efforts to cure chronic HBV. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

Improved Thermally Grown Oxide Scale in Air Plasma Sprayed NiCrAlY/Nano-YSZ Coatings

International Nuclear Information System (INIS)

Daroonparvar, M.; Yajid, M.A.M.; Yusof, N.M.; Hussain, M.S.

2013-01-01

Oxidation has been considered as one of the principal disruptive factors in thermal barrier coating systems during service. So, oxidation behavior of thermal barrier coating (TBC) systems with nano structured and micro structured YSZ coatings was investigated at 1000 degree c for 24 h, 48 h, and 120 h. Air plasma sprayed nano-YSZ coating exhibited a tri modal structure. Microstructural characterization also demonstrated an improved thermally grown oxide scale containing lower spinels in nano-TBC system after 120 h of oxidation. This phenomenon is mainly related to the unique structure of the nano-YSZ coating, which acted as a strong barrier for oxygen diffusion into the TBC system at elevated temperatures. Nearly continues but thinner Al 2 O 3 layer formation at the NiCrAlY/nano-YSZ interface was seen, due to lower oxygen infiltration into the system. Under this condition, spinels formation and growth on the Al 2 O 3 oxide scale were diminished in nano-TBC system compared to normal TBC system.

Wafer scale nano-membrane supported on a silicon microsieve using thin-film transfer technology

NARCIS (Netherlands)

Unnikrishnan, S.; Jansen, Henricus V.; Berenschot, Johan W.; Elwenspoek, Michael Curt

A new micromachining method to fabricate wafer scale nano-membranes is described. The delicate thin-film nano-membrane is supported on a robust silicon microsieve fabricated by plasma etching. The silicon sieve is micromachined independently of the thin-film, which is later transferred onto it by

Exploring Chondrule and CAI Rims Using Micro- and Nano-Scale Petrological and Compositional Analysis

Science.gov (United States)

Cartwright, J. A.; Perez-Huerta, A.; Leitner, J.; Vollmer, C.

2017-12-01

As the major components within chondrites, chondrules (mm-sized droplets of quenched silicate melt) and calcium-aluminum-rich inclusions (CAI, refractory) represent the most abundant and the earliest materials that solidified from the solar nebula. However, the exact formation mechanisms of these clasts, and whether these processes are related, remains unconstrained, despite extensive petrological and compositional study. By taking advantage of recent advances in nano-scale tomographical techniques, we have undertaken a combined micro- and nano-scale study of CAI and chondrule rim morphologies, to investigate their formation mechanisms. The target lithologies for this research are Wark-Lovering rims (WLR), and fine-grained rims (FGR) around CAIs and chondrules respectively, present within many chondrites. The FGRs, which are up to 100 µm thick, are of particular interest as recent studies have identified presolar grains within them. These grains predate the formation of our Solar System, suggesting FGR formation under nebular conditions. By contrast, WLRs are 10-20 µm thick, made of different compositional layers, and likely formed by flash-heating shortly after CAI formation, thus recording nebular conditions. A detailed multi-scale study of these respective rims will enable us to better understand their formation histories and determine the potential for commonality between these two phases, despite reports of an observed formation age difference of up to 2-3 Myr. We are using a combination of complimentary techniques on our selected target areas: 1) Micro-scale characterization using standard microscopic and compositional techniques (SEM-EBSD, EMPA); 2) Nano-scale characterization of structures using transmission electron microscopy (TEM) and elemental, isotopic and tomographic analysis with NanoSIMS and atom probe tomography (APT). Preliminary nano-scale APT analysis of FGR morphologies within the Allende carbonaceous chondrite has successfully discerned

Multi Scale Micro and Nano Metrology for Advanced Precision Moulding Technologies

DEFF Research Database (Denmark)

Quagliotti, Danilo

dimensions of the novel micro and nano production. Nowadays, design methodologies and concurrent tolerance guidelines are not yet available for advanced micro manufacture. Moreover, there are no shared methodologies that deals with the uncertainty evaluation of feature of size in the sub-millimetre scale......The technological revolution that has deeply influenced the manufacturing industry over the past two decades opened up new possibilities for the realisation of advanced micro and nano systems but, at the same time, traditional techniques for quality assurance became not adequate any longer......, as the technology progressed. The gap between the needs of the manufacturing industry and the well-organized structure of the dimensional and geometrical metrology appeared, above all, related to the methodologies and, also, to the instrumentation used to deal with the incessant scaling down of the critical...

Micro and Nano-Scale Technologies for Cell Mechanics

Directory of Open Access Journals (Sweden)

Mustafa Unal

2014-10-01

Full Text Available Cell mechanics is a multidisciplinary field that bridges cell biology, fundamental mechanics, and micro and nanotechnology, which synergize to help us better understand the intricacies and the complex nature of cells in their native environment. With recent advances in nanotechnology, microfabrication methods and micro-electro-mechanical-systems (MEMS, we are now well situated to tap into the complex micro world of cells. The field that brings biology and MEMS together is known as Biological MEMS (BioMEMS. BioMEMS take advantage of systematic design and fabrication methods to create platforms that allow us to study cells like never before. These new technologies have been rapidly advancing the study of cell mechanics. This review article provides a succinct overview of cell mechanics and comprehensively surveys micro and nano-scale technologies that have been specifically developed for and are relevant to the mechanics of cells. Here we focus on micro and nano-scale technologies, and their applications in biology and medicine, including imaging, single cell analysis, cancer cell mechanics, organ-on-a-chip systems, pathogen detection, implantable devices, neuroscience and neurophysiology. We also provide a perspective on the future directions and challenges of technologies that relate to the mechanics of cells.

Closed-form approximation and numerical validation of the influence of van der Waals force on electrostatic cantilevers at nano-scale separations

Energy Technology Data Exchange (ETDEWEB)

Ramezani, Asghar [School of Mechanical Engineering, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Alasty, Aria [Center of Excellence in Design, Robotics, and Automation (CEDRA), School of Mechanical Engineering, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Akbari, Javad [Center of Excellence in Design, Robotics, and Automation (CEDRA), School of Mechanical Engineering, Sharif University of Technology, Tehran (Iran, Islamic Republic of)

2008-01-09

In this paper the two-point boundary value problem (BVP) of the cantilever deflection at nano-scale separations subjected to van der Waals and electrostatic forces is investigated using analytical and numerical methods to obtain the instability point of the beam. In the analytical treatment of the BVP, the nonlinear differential equation of the model is transformed into the integral form by using the Green's function of the cantilever beam. Then, closed-form solutions are obtained by assuming an appropriate shape function for the beam deflection to evaluate the integrals. In the numerical method, the BVP is solved with the MATLAB BVP solver, which implements a collocation method for obtaining the solution of the BVP. The large deformation theory is applied in numerical simulations to study the effect of the finite kinematics on the pull-in parameters of cantilevers. The centerline of the beam under the effect of electrostatic and van der Waals forces at small deflections and at the point of instability is obtained numerically. In computing the centerline of the beam, the axial displacement due to the transverse deformation of the beam is taken into account, using the inextensibility condition. The pull-in parameters of the beam are computed analytically and numerically under the effects of electrostatic and/or van der Waals forces. The detachment length and the minimum initial gap of freestanding cantilevers, which are the basic design parameters, are determined. The results of the analytical study are compared with the numerical solutions of the BVP. The proposed methods are validated by the results published in the literature.

Design Optimization of Radionuclide Nano-Scale Batteries

International Nuclear Information System (INIS)

Schoenfeld, D.W.; Tulenko, J.S.; Wang, J.; Smith, B.

2004-01-01

Radioisotopes have been used for power sources in heart pacemakers and space applications dating back to the 50's. Two key properties of radioisotope power sources are high energy density and long half-life compared to chemical batteries. The tritium battery used in heart pacemakers exceeds 500 mW--hr, and is being evaluated by the University of Florida for feasibility as a MEMS (MicroElectroMechanical Systems) power source. Conversion of radioisotope sources into electrical power within the constraints of nano-scale dimensions requires cutting-edge technologies and novel approaches. Some advances evolving in the III-V and II-IV semiconductor families have led to a broader consideration of radioisotopes rather free of radiation damage limitations. Their properties can lead to novel battery configurations designed to convert externally located emissions from a highly radioactive environment. This paper presents results for the analytical computational assisted design and modeling of semiconductor prototype nano-scale radioisotope nuclear batteries from MCNP and EGS programs. The analysis evaluated proposed designs and was used to guide the selection of appropriate geometries, material properties, and specific activities to attain power requirements for the MEMS batteries. Plans utilizing high specific activity radioisotopes were assessed in the investigation of designs employing multiple conversion cells and graded junctions with varying band gap properties. Voltage increases sought by serial combination of VOC s are proposed to overcome some of the limitations of a low power density. The power density is directly dependent on the total active areas

Combustion synthesis of CaSc{sub 2}O{sub 4}:Ce{sup 3+} nano-phosphors in a closed system

Energy Technology Data Exchange (ETDEWEB)

Peng Wenfang; Zou Shaoyu; Liu Guanxi; Xiao Quanlan; Zhang Rui; Xie Lijuan; Cao Liwei [Department of Chemistry, Jinan University, Guangzhou 510632 (China); Meng Jianxin, E-mail: tmjx@jnu.edu.cn [Institute of Nano-Chemistry, Jinan University, Guangzhou 510632 (China); Liu Yingliang [Institute of Nano-Chemistry, Jinan University, Guangzhou 510632 (China)

2011-06-09

Highlights: > CaSc{sub 2}O{sub 4}:Ce{sup 3+} nano-phosphors can be prepared by a single-step combustion method. > The ignition temperature is the lowest in the combustion synthesis of Ce{sup 3+}/Eu{sup 2+} doped phosphors. > The as-prepared nano-phosphors give a uniform particle size in the range of 15-20 nm and have highly dispersity and fluorescence intensity. > It is a convenient method for preparation of monodispersed oxide nano-phosphors, especially those being sensitive to air at high temperature. - Abstract: The CaSc{sub 2}O{sub 4}:Ce{sup 3+} nano-phosphors were successfully prepared by a single-step combustion method at an ignition temperature as low as 200 deg. C in a closed autoclave using glycine as a fuel and PEG4000 as a dispersant. The samples were characterized by X-ray diffraction (XRD), photoluminescence (PL) spectroscopy, scanning electron microscopy (SEM) and transmission electron microscope (TEM). The results revealed that CaSc{sub 2}O{sub 4}:Ce{sup 3+} nano-phosphors can be conveniently prepared at an ignition temperature as low as 200 deg. C, which was much lower than that in the ordinary combustion methods. The optimized ignition temperature was 220 deg. C. The CaSc{sub 2}O{sub 4}:Ce{sup 3+} nano-phosphors give a uniform particle size in the range of 15-20 nm. The low ignition temperature and the addition of PEG4000 dispersant play important roles in the formation of small sized nanoparticles. The as-prepared nano-phosphors were incompact aggregates, but highly dispersed nano-phosphors can be obtained after further ultrasonic treatment. The CaSc{sub 2}O{sub 4}:Ce{sup 3+} nano-phosphors give satisfactory luminescence characteristic benefiting from the closed circumstance, in which cerium atoms can be isolated from the oxidizing atmosphere and non-fluorescent Ce{sup 4+} ions can be ruled out. The present highly dispersed CaSc{sub 2}O{sub 4}:Ce{sup 3+} nano-phosphors with efficient fluorescence are promising in the field of biological labeling

Fabrication of a 3D micro/nano dual-scale carbon array and its demonstration as the microelectrodes for supercapacitors

Science.gov (United States)

Jiang, Shulan; Shi, Tielin; Gao, Yang; Long, Hu; Xi, Shuang; Tang, Zirong

2014-04-01

An easily accessible method is proposed for the fabrication of a 3D micro/nano dual-scale carbon array with a large surface area. The process mainly consists of three critical steps. Firstly, a hemispherical photoresist micro-array was obtained by the cost-effective nanoimprint lithography process. Then the micro-array was transformed into hierarchical structures with longitudinal nanowires on the microstructure surface by oxygen plasma etching. Finally, the micro/nano dual-scale carbon array was fabricated by carbonizing these hierarchical photoresist structures. It has also been demonstrated that the micro/nano dual-scale carbon array can be used as the microelectrodes for supercapacitors by the electrodeposition of a manganese dioxide (MnO2) film onto the hierarchical carbon structures with greatly enhanced electrochemical performance. The specific gravimetric capacitance of the deposited micro/nano dual-scale microelectrodes is estimated to be 337 F g-1 at the scan rate of 5 mV s-1. This proposed approach of fabricating a micro/nano dual-scale carbon array provides a facile way in large-scale microstructures’ manufacturing for a wide variety of applications, including sensors and on-chip energy storage devices.

Fabrication of a 3D micro/nano dual-scale carbon array and its demonstration as the microelectrodes for supercapacitors

International Nuclear Information System (INIS)

Jiang, Shulan; Shi, Tielin; Gao, Yang; Long, Hu; Xi, Shuang; Tang, Zirong

2014-01-01

An easily accessible method is proposed for the fabrication of a 3D micro/nano dual-scale carbon array with a large surface area. The process mainly consists of three critical steps. Firstly, a hemispherical photoresist micro-array was obtained by the cost-effective nanoimprint lithography process. Then the micro-array was transformed into hierarchical structures with longitudinal nanowires on the microstructure surface by oxygen plasma etching. Finally, the micro/nano dual-scale carbon array was fabricated by carbonizing these hierarchical photoresist structures. It has also been demonstrated that the micro/nano dual-scale carbon array can be used as the microelectrodes for supercapacitors by the electrodeposition of a manganese dioxide (MnO 2 ) film onto the hierarchical carbon structures with greatly enhanced electrochemical performance. The specific gravimetric capacitance of the deposited micro/nano dual-scale microelectrodes is estimated to be 337 F g −1  at the scan rate of 5 mV s −1 . This proposed approach of fabricating a micro/nano dual-scale carbon array provides a facile way in large-scale microstructures’ manufacturing for a wide variety of applications, including sensors and on-chip energy storage devices. (paper)

Special Issue on the Second International Workshop on Micro- and Nano-Scale Thermal Radiation

Science.gov (United States)

Zhang, Zhuomin; Liu, Linhua; Zhu, Qunzhi; Mengüç, M. Pinar

2015-06-01

Micro- and nano-scale thermal radiation has become one of the fastest growing research areas because of advances in nanotechnology and the development of novel materials. The related research and development includes near-field radiation transfer, spectral and directional selective emitters and receivers, plasmonics, metamaterials, and novel nano-scale fabrication techniques. With the advances in these areas, important applications in energy harvesting such as solar cells and thermophotovoltaics, nanomanufacturing, biomedical sensing, thermal imaging as well as data storage with the localized heating/cooling have been pushed to higher levels.

Evaporation characteristics of thin film liquid argon in nano-scale confinement: A molecular dynamics study

Science.gov (United States)

Hasan, Mohammad Nasim; Shavik, Sheikh Mohammad; Rabbi, Kazi Fazle; Haque, Mominul

2016-07-01

Molecular dynamics simulation has been carried out to explore the evaporation characteristics of thin liquid argon film in nano-scale confinement. The present study has been conducted to realize the nano-scale physics of simultaneous evaporation and condensation inside a confined space for a three phase system with particular emphasis on the effect of surface wetting conditions. The simulation domain consisted of two parallel platinum plates; one at the top and another at the bottom. The fluid comprised of liquid argon film at the bottom plate and vapor argon in between liquid argon and upper plate of the domain. Considering hydrophilic and hydrophobic nature of top and bottom surfaces, two different cases have been investigated: (i) Case A: Both top and bottom surfaces are hydrophilic, (ii) Case B: both top and bottom surfaces are hydrophobic. For all cases, equilibrium molecular dynamics (EMD) was performed to reach equilibrium state at 90 K. Then the lower wall was set to four different temperatures such as 110 K, 120 K, 130 K and 140 K to perform non-equilibrium molecular dynamics (NEMD). The variation of temperature and density as well as the variation of system pressure with respect to time were closely monitored for each case. The heat fluxes normal to top and bottom walls were estimated and discussed to illuminate the effectiveness of heat transfer in both hydrophilic and hydrophobic confinement at various boundary temperatures of the bottom plate.

Indentation analysis of nano-particle using nano-contact mechanics models during nano-manipulation based on atomic force microscopy

International Nuclear Information System (INIS)

Daeinabi, Khadijeh; Korayem, Moharam Habibnejad

2011-01-01

Atomic force microscopy is applied to measure intermolecular forces and mechanical properties of materials, nano-particle manipulation, surface scanning and imaging with atomic accuracy in the nano-world. During nano-manipulation process, contact forces cause indentation in contact area between nano-particle and tip/substrate which is considerable at nano-scale and affects the nano-manipulation process. Several nano-contact mechanics models such as Hertz, Derjaguin–Muller–Toporov (DMT), Johnson–Kendall–Roberts–Sperling (JKRS), Burnham–Colton–Pollock (BCP), Maugis–Dugdale (MD), Carpick–Ogletree–Salmeron (COS), Pietrement–Troyon (PT), and Sun et al. have been applied as the continuum mechanics approaches at nano-scale. In this article, indentation depth and contact radius between tip and substrate with nano-particle for both spherical and conical tip shape during nano-manipulation process are analyzed and compared by applying theoretical, semiempirical, and empirical nano-contact mechanics models. The effects of adhesion force, as the main contrast point in different nano-contact mechanics models, on nano-manipulation analysis is investigated for different contact radius, and the critical point is discussed for mentioned models.

Synthesis and Characterization of Nano Scale YBCO

International Nuclear Information System (INIS)

Sukirman, E.; Wisnu AA; Yustinus P; Sahidin W, D.; Rina M, Th.

2009-01-01

Synthesis and characterization of the nano scale YBCO superconductor have been performed. The nano scale superconductor was synthesized from YBCO system (YBa 2 Cu 3 O 7-X ). Raw materials, namely Y 2 O 3 , BaCO 3 , and Cu°, were balanced and mixed with ethanol using magnetic steering as a churn in a beaker glass. Then, the precursor was calcined at T k = 900°C for 5 hours and repeated it until three times. The resulting precursor was ground by using High Energy Milling (HEM) for t = 0, 30, 50, 70, and 90 hour and hereinafter precursors are successively referred as YKM-00, YKM-30, YKM-50, YKM-70, and YKM-90. The resulting powders phase were characterized by means of x-ray diffraction technique using the Rietveld analysis method. Precursor of YKM-90 was pressed into pellets, and then sintered at various temperatures and periods. The sample phase was then characterized by using the Rietveld analysis method based on the x-ray diffraction data. The crystallites size were calculated using Scherrer formula. Results of analysis indicate that by minimizing crystallites size, period of sinter can be shortened from 10 to 1 hour, resulting crystallite size of D = 925 Å, critical current density of J c = 4 A / cm 2 , and can be grown of about 15 weight % of 211-phase in a matrix of 123-phase. The decrease of crystallite size will generate a change in physical properties dramatically, if the crystallite size of the material, D is smaller or equal to the coherence length of 10 Å. (author)

Pitfalls of DNA Quantification Using DNA-Binding Fluorescent Dyes and Suggested Solutions.

Science.gov (United States)

Nakayama, Yuki; Yamaguchi, Hiromi; Einaga, Naoki; Esumi, Mariko

2016-01-01

The Qubit fluorometer is a DNA quantification device based on the fluorescence intensity of fluorescent dye binding to double-stranded DNA (dsDNA). Qubit is generally considered useful for checking DNA quality before next-generation sequencing because it measures intact dsDNA. To examine the most accurate and suitable methods for quantifying DNA for quality assessment, we compared three quantification methods: NanoDrop, which measures UV absorbance; Qubit; and quantitative PCR (qPCR), which measures the abundance of a target gene. For the comparison, we used three types of DNA: 1) DNA extracted from fresh frozen liver tissues (Frozen-DNA); 2) DNA extracted from formalin-fixed, paraffin-embedded liver tissues comparable to those used for Frozen-DNA (FFPE-DNA); and 3) DNA extracted from the remaining fractions after RNA extraction with Trizol reagent (Trizol-DNA). These DNAs were serially diluted with distilled water and measured using three quantification methods. For Frozen-DNA, the Qubit values were not proportional to the dilution ratio, in contrast with the NanoDrop and qPCR values. This non-proportional decrease in Qubit values was dependent on a lower salt concentration, and over 1 mM NaCl in the DNA solution was required for the Qubit measurement. For FFPE-DNA, the Qubit values were proportional to the dilution ratio and were lower than the NanoDrop values. However, electrophoresis revealed that qPCR reflected the degree of DNA fragmentation more accurately than Qubit. Thus, qPCR is superior to Qubit for checking the quality of FFPE-DNA. For Trizol-DNA, the Qubit values were proportional to the dilution ratio and were consistently lower than the NanoDrop values, similar to FFPE-DNA. However, the qPCR values were higher than the NanoDrop values. Electrophoresis with SYBR Green I and single-stranded DNA (ssDNA) quantification demonstrated that Trizol-DNA consisted mostly of non-fragmented ssDNA. Therefore, Qubit is not always the most accurate method for

Compressing a confined DNA: from nano-channel to nano-cavity

Science.gov (United States)

Sakaue, Takahiro

2018-06-01

We analyze the behavior of a semiflexible polymer confined in nanochannel under compression in axial direction. Key to our discussion is the identification of two length scales; the correlation length ξ of concentration fluctuation and what we call the segregation length . These length scales, while degenerate in uncompressed state in nanochannel, generally split as upon compression, and the way they compete with the system size during the compression determines the crossover from quasi-1D nanochannel to quasi-0D nanocavity behaviors. For a flexible polymer, the story becomes very simple, which corresponds to a special limit of our description, but a much richer behavior is expected for a semiflexible polymer relevant to DNA in confined spaces. We also briefly discuss the dynamical properties of the compressed polymer.

DNA gyrase with a single catalytic tyrosine can catalyze DNA supercoiling by a nicking-closing mechanism

Science.gov (United States)

Gubaev, Airat; Weidlich, Daniela; Klostermeier, Dagmar

2016-01-01

The topological state of DNA is important for replication, recombination and transcription, and is regulated in vivo by DNA topoisomerases. Gyrase introduces negative supercoils into DNA at the expense of ATP hydrolysis. It is the accepted view that gyrase achieves supercoiling by a strand passage mechanism, in which double-stranded DNA is cleaved, and a second double-stranded segment is passed through the gap, converting a positive DNA node into a negative node. We show here that gyrase with only one catalytic tyrosine that cleaves a single strand of its DNA substrate can catalyze DNA supercoiling without strand passage. We propose an alternative mechanism for DNA supercoiling via nicking and closing of DNA that involves trapping, segregation and relaxation of two positive supercoils. In contrast to DNA supercoiling, ATP-dependent relaxation and decatenation of DNA by gyrase lacking the C-terminal domains require both tyrosines and strand passage. Our results point towards mechanistic plasticity of gyrase and might pave the way for finding novel and specific mechanism-based gyrase inhibitors. PMID:27557712

Phototoxicity and Dosimetry of Nano-scale Titanium Dioxide in Aquatic Organisms

Science.gov (United States)

We have been testing nanoscale TiO2 (primarily Evonik P25) in acute exposures to identify and quantify its phototoxicity under solar simulated radiation (SSR), and to develop dose metrics reflective of both nano-scale properties and the photon component of its potency. Several e...

Crystallization of high-strength nano-scale leucite glass-ceramics.

Science.gov (United States)

Theocharopoulos, A; Chen, X; Wilson, R M; Hill, R; Cattell, M J

2013-11-01

Fine-grained, high strength, translucent leucite dental glass-ceramics are synthesized via controlled crystallization of finely milled glass powders. The objectives of this study were to utilize high speed planetary milling of an aluminosilicate glass for controlled surface crystallization of nano-scale leucite glass-ceramics and to test the biaxial flexural strength. An aluminosilicate glass was synthesized, attritor or planetary milled and heat-treated. Glasses and glass-ceramics were characterized using particle size analysis, X-ray diffraction and scanning electron microscopy. Experimental (fine and nanoscale) and commercial (Ceramco-3, IPS Empress Esthetic) leucite glass-ceramics were tested using the biaxial flexural strength (BFS) test. Gaussian and Weibull statistics were applied. Experimental planetary milled glass-ceramics showed an increased leucite crystal number and nano-scale median crystal sizes (0.048-0.055 μm(2)) as a result of glass particle size reduction and heat treatments. Experimental materials had significantly (p0.05) strength difference. All other groups' mean BFS and characteristic strengths were found to be significantly different (pglass-ceramics with high flexural strength. These materials may help to reduce problems associated with brittle fracture of all-ceramic restorations and give reduced enamel wear. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Intrinsic flexibility of B-DNA: the experimental TRX scale.

Science.gov (United States)

Heddi, Brahim; Oguey, Christophe; Lavelle, Christophe; Foloppe, Nicolas; Hartmann, Brigitte

2010-01-01

B-DNA flexibility, crucial for DNA-protein recognition, is sequence dependent. Free DNA in solution would in principle be the best reference state to uncover the relation between base sequences and their intrinsic flexibility; however, this has long been hampered by a lack of suitable experimental data. We investigated this relationship by compiling and analyzing a large dataset of NMR (31)P chemical shifts in solution. These measurements reflect the BI BII equilibrium in DNA, intimately correlated to helicoidal descriptors of the curvature, winding and groove dimensions. Comparing the ten complementary DNA dinucleotide steps indicates that some steps are much more flexible than others. This malleability is primarily controlled at the dinucleotide level, modulated by the tetranucleotide environment. Our analyses provide an experimental scale called TRX that quantifies the intrinsic flexibility of the ten dinucleotide steps in terms of Twist, Roll, and X-disp (base pair displacement). Applying the TRX scale to DNA sequences optimized for nucleosome formation reveals a 10 base-pair periodic alternation of stiff and flexible regions. Thus, DNA flexibility captured by the TRX scale is relevant to nucleosome formation, suggesting that this scale may be of general interest to better understand protein-DNA recognition.

Nano-scale gene delivery systems; current technology, obstacles, and future directions.

Science.gov (United States)

Garcia-Guerra, Antonio; Dunwell, Thomas L; Trigueros, Sonia

2018-01-07

Within the different applications of nanomedicine currently being developed, nano-gene delivery is appearing as an exciting new technique with the possibility to overcome recognised hurdles and fulfill several biological and medical needs. The central component of all delivery systems is the requirement for the delivery of genetic material into cells, and for them to eventually reside in the nucleus where their desired function will be exposed. However, genetic material does not passively enter cells; thus, a delivery system is necessary. The emerging field of nano-gene delivery exploits the use of new materials and the properties that arise at the nanometre-scale to produce delivery vectors that can effectively deliver genetic material into a variety of different types of cells. The novel physicochemical properties of the new delivery vectors can be used to address the current challenges existing in nucleic acid delivery in vitro and in vivo. While there is a growing interest in nanostructure-based gene delivery, the field is still in its infancy, and there is yet much to discover about nanostructures and their physicochemical properties in a biological context. We carry out an organized and focused search of bibliographic databases. Our results suggest that despite new breakthroughs in nanostructure synthesis and advanced characterization techniques, we still face many barriers in producing highly efficient and non-toxic delivery systems. In this review, we overview the types of systems currently used for clinical and biomedical research applications along with their advantages and disadvantages, as well as discussing barriers that arise from nano-scale interactions with biological material. In conclusion, we hope that by bringing the far reaching multidisciplinary nature of nano-gene delivery to light, new targeted nanotechnology-bases strategies are developed to overcome the major challenges covered in this review. Copyright© Bentham Science Publishers; For

Strengthening effect of nano-scaled precipitates in Ta alloying layer induced by high current pulsed electron beam

Energy Technology Data Exchange (ETDEWEB)

Tang, Guangze; Luo, Dian; Fan, Guohua [School of Material Science & Engineering, Harbin Institute of Technology, Harbin 150001 (China); Ma, Xinxin, E-mail: maxin@hit.edu.cn [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Wang, Liqin [School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001 (China)

2017-05-01

Highlights: • Ta alloying layer are fabricated by magnetron sputtering and high current pulsed electron beam. • Nano-scaled TaC precipitates forms within the δ-Fe grain after tempering treatment. • The mean diameter of TaC particles is about 5–8 nm. • The hardness of alloying layer increased by over 50% after formation of nano-scaled TaC particle. - Abstract: In this study, the combination of magnetron sputtering and high current pulsed electron beam are used for surface alloying treatment of Ta film on high speed steel. And the Ta alloying layer is about 6 μm. After tempering treatment, TaC phase forms in Ta alloying layer when the treated temperature is over 823 K. Through the TEM and HRTEM observation, a large amount of nano-scaled precipitates (mean diameter 5–8 nm) form within the δ-Fe grain in Ta alloying layer after tempering treatment and these nano-scaled precipitates are confirmed as TaC particles, which contribute to the strengthening effect of the surface alloying layer. The hardness of tempered alloying layer can reach to 18.1 GPa when the treated temperature is 823 K which increase by 50% comparing with the untreated steel sample before surface alloying treatment.

Nano-ranged low-energy ion-beam-induced DNA transfer in biological cells

Energy Technology Data Exchange (ETDEWEB)

Yu, L.D., E-mail: yuld@fnrf.science.cmu.ac.th [Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Wongkham, W. [Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Prakrajang, K. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Sangwijit, K.; Inthanon, K. [Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thongkumkoon, P. [Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Wanichapichart, P. [Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Membrane Science and Technology Research Center, Department of Physics, Faculty of Science, Prince of Songkla University, Hat Yai, Songkla 90112 (Thailand); Anuntalabhochai, S. [Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand)

2013-06-15

Low-energy ion beams at a few tens of keV were demonstrated to be able to induce exogenous macromolecules to transfer into plant and bacterial cells. In the process, the ion beam with well controlled energy and fluence bombarded living cells to cause certain degree damage in the cell envelope in nanoscales to facilitate the macromolecules such as DNA to pass through the cell envelope and enter the cell. Consequently, the technique was applied for manipulating positive improvements in the biological species. This physical DNA transfer method was highly efficient and had less risk of side-effects compared with chemical and biological methods. For better understanding of mechanisms involved in the process, a systematic study on the mechanisms was carried out. Applications of the technique were also expanded from DNA transfer in plant and bacterial cells to DNA transfection in human cancer cells potentially for the stem cell therapy purpose. Low-energy nitrogen and argon ion beams that were applied in our experiments had ranges of 100 nm or less in the cell envelope membrane which was majorly composed of polymeric cellulose. The ion beam bombardment caused chain-scission dominant damage in the polymer and electrical property changes such as increase in the impedance in the envelope membrane. These nano-modifications of the cell envelope eventually enhanced the permeability of the envelope membrane to favor the DNA transfer. The paper reports details of our research in this direction.

Nano-ranged low-energy ion-beam-induced DNA transfer in biological cells

International Nuclear Information System (INIS)

Yu, L.D.; Wongkham, W.; Prakrajang, K.; Sangwijit, K.; Inthanon, K.; Thongkumkoon, P.; Wanichapichart, P.; Anuntalabhochai, S.

2013-01-01

Low-energy ion beams at a few tens of keV were demonstrated to be able to induce exogenous macromolecules to transfer into plant and bacterial cells. In the process, the ion beam with well controlled energy and fluence bombarded living cells to cause certain degree damage in the cell envelope in nanoscales to facilitate the macromolecules such as DNA to pass through the cell envelope and enter the cell. Consequently, the technique was applied for manipulating positive improvements in the biological species. This physical DNA transfer method was highly efficient and had less risk of side-effects compared with chemical and biological methods. For better understanding of mechanisms involved in the process, a systematic study on the mechanisms was carried out. Applications of the technique were also expanded from DNA transfer in plant and bacterial cells to DNA transfection in human cancer cells potentially for the stem cell therapy purpose. Low-energy nitrogen and argon ion beams that were applied in our experiments had ranges of 100 nm or less in the cell envelope membrane which was majorly composed of polymeric cellulose. The ion beam bombardment caused chain-scission dominant damage in the polymer and electrical property changes such as increase in the impedance in the envelope membrane. These nano-modifications of the cell envelope eventually enhanced the permeability of the envelope membrane to favor the DNA transfer. The paper reports details of our research in this direction.

Mass production of polymer nano-wires filled with metal nano-particles.

Science.gov (United States)

Lomadze, Nino; Kopyshev, Alexey; Bargheer, Matias; Wollgarten, Markus; Santer, Svetlana

2017-08-17

Despite the ongoing progress in nanotechnology and its applications, the development of strategies for connecting nano-scale systems to micro- or macroscale elements is hampered by the lack of structural components that have both, nano- and macroscale dimensions. The production of nano-scale wires with macroscale length is one of the most interesting challenges here. There are a lot of strategies to fabricate long nanoscopic stripes made of metals, polymers or ceramics but none is suitable for mass production of ordered and dense arrangements of wires at large numbers. In this paper, we report on a technique for producing arrays of ordered, flexible and free-standing polymer nano-wires filled with different types of nano-particles. The process utilizes the strong response of photosensitive polymer brushes to irradiation with UV-interference patterns, resulting in a substantial mass redistribution of the polymer material along with local rupturing of polymer chains. The chains can wind up in wires of nano-scale thickness and a length of up to several centimeters. When dispersing nano-particles within the film, the final arrangement is similar to a core-shell geometry with mainly nano-particles found in the core region and the polymer forming a dielectric jacket.

Electron transport in nano-scaled piezoelectronic devices

Science.gov (United States)

Jiang, Zhengping; Kuroda, Marcelo A.; Tan, Yaohua; Newns, Dennis M.; Povolotskyi, Michael; Boykin, Timothy B.; Kubis, Tillmann; Klimeck, Gerhard; Martyna, Glenn J.

2013-05-01

The Piezoelectronic Transistor (PET) has been proposed as a post-CMOS device for fast, low-power switching. In this device, the piezoresistive channel is metalized via the expansion of a relaxor piezoelectric element to turn the device on. The mixed-valence compound SmSe is a good choice of PET channel material because of its isostructural pressure-induced continuous metal insulator transition, which is well characterized in bulk single crystals. Prediction and optimization of the performance of a realistic, nano-scaled PET based on SmSe requires the understanding of quantum confinement, tunneling, and the effect of metal interface. In this work, a computationally efficient empirical tight binding (ETB) model is developed for SmSe to study quantum transport in these systems and the scaling limit of PET channel lengths. Modulation of the SmSe band gap under pressure is successfully captured by ETB, and ballistic conductance shows orders of magnitude change under hydrostatic strain, supporting operability of the PET device at nanoscale.

Nano-scaled graphene platelets with a high length-to-width aspect ratio

Science.gov (United States)

Zhamu, Aruna; Guo, Jiusheng; Jang, Bor Z.

2010-09-07

This invention provides a nano-scaled graphene platelet (NGP) having a thickness no greater than 100 nm and a length-to-width ratio no less than 3 (preferably greater than 10). The NGP with a high length-to-width ratio can be prepared by using a method comprising (a) intercalating a carbon fiber or graphite fiber with an intercalate to form an intercalated fiber; (b) exfoliating the intercalated fiber to obtain an exfoliated fiber comprising graphene sheets or flakes; and (c) separating the graphene sheets or flakes to obtain nano-scaled graphene platelets. The invention also provides a nanocomposite material comprising an NGP with a high length-to-width ratio. Such a nanocomposite can become electrically conductive with a small weight fraction of NGPs. Conductive composites are particularly useful for shielding of sensitive electronic equipment against electromagnetic interference (EMI) or radio frequency interference (RFI), and for electrostatic charge dissipation.

Nano-scaled hydroxyapatite/silk fibroin sheets support osteogenic differentiation of rat bone marrow mesenchymal cells

International Nuclear Information System (INIS)

Tanaka, Toshimitsu; Hirose, Motohiro; Kotobuki, Noriko; Ohgushi, Hajime; Furuzono, Tsutomu; Sato, Junichi

2007-01-01

A novel biomaterial that was composed of nano-scaled sintered hydroxyapatite (HAp) and silk fibroin (SF) was fabricated. We cultured rat marrow mesenchymal cells (MMCs) on this biomaterial (nano-HAp/SF sheet), on bare SF sheets, and on tissue culture polystyrene (TCPS) dishes as controls, then evaluated cell adhesion, proliferation, and differentiation of the MMCs. After 1 h of culture, a large number of viable cells were observed on the nano-HAp/SF sheets in comparison to the controls. In addition, after 3 h of culture, the morphology of the cells on the nano-HAp/SF sheets was quite different from that on the SF sheets. MMCs extrude their cytoplasmic processes to nano-HAp particles and are well attached to the sheets. After 14 days of culture, under osteogenic conditions, the alkaline phosphatase (ALP) activity and bone-specific osteocalcin secretion of the cells on nano-HAp/SF sheets were higher than were those on the controls. These results indicated that the surface of the nano-HAp/SF sheets is covered with appropriate HAp crystal for MMC adhesion/proliferation and that the sheets effectively support the osteogenic differentiation of MMCs. Therefore, the nano-HAp/SF sheet is an effective biomaterial that is applicable in bone reconstruction surgery

Broadband spectroscopy of magnetic response in a nano-scale magnetic wire

International Nuclear Information System (INIS)

Yamaguchi, A.; Motoi, K.; Miyajima, H.; Utsumi, Y.

2014-01-01

We measure the broadband spectra of magnetic response in a single layered ferromagnetic nano-scale wire in order to investigate the size effect on the ferromagnetic resonance. We found that the resonance frequency difference between 300-nm- and 5-μm-wide wires was varied by about 5 GHz due to the shape anisotropy. Furthermore, we experimentally detected the magnetization precession induced by the thermal fluctuation via the rectification of a radio-frequency (rf) current by incorporating an additional direct current (dc) by using Wheatstone bridge circuit. Our investigation renders that the shape anisotropy is of great importance to control the resonance frequency and to provide thermal stability of the microwave devices. - Highlights: • We describe an experimental investigation of the magnetic response of a single layered ferromagnetic nano-scale wire. • We present the conventional broadband microwave spectroscopy with a vector network analyzer and rectifying spectroscopy obtained with a Wheatstone bridge technique. • The investigation enables us to characterize the size effect on the ferromagnetic response and also to detect the magnetization precession induced by the thermal fluctuations

Imaging Catalysts at Work: A Hierarchical Approach from the Macro- to the Meso- and Nano-scale

DEFF Research Database (Denmark)

Grunwaldt, Jan-Dierk; Wagner, Jakob Birkedal; Dunin-Borkowski, Rafal E.

2013-01-01

This review highlights the importance of developing multi-scale characterisation techniques for analysing operating catalysts in their working environment. We emphasise that a hierarchy of insitu techniques that provides macro-, meso- and nano-scale information is required to elucidate and optimise....../heat/mass transport gradients in shaped catalysts and catalyst grains and c)meso- and nano-scale information about particles and clusters, whose physical and electronic properties are linked directly to the micro-kinetic behaviour of the catalysts. Techniques such as X-ray diffraction (XRD), infrared (IR), Raman, X......-ray photoelectron spectroscopy (XPS), UV/Vis, and X-ray absorption spectroscopy (XAS), which have mainly provided global atomic scale information, are being developed to provide the same information on a more local scale, often with sub-second time resolution. X-ray microscopy, both in the soft and more recently...

Nano structures for Medical Diagnostics Md

International Nuclear Information System (INIS)

Bellah, M.; Iqbal, S.M.; Bellah, M.; Iqbal, S.M.; Christensen, S.M.; Iqbal, S.M.; Iqbal, S.M.

2012-01-01

Nano technology is the art of manipulating materials on atomic or molecular scales especially to build nano scale structures and devices. The field is expanding quickly, and a lot of work is ongoing in the design, characterization, synthesis, and application of materials, structures, devices, and systems by controlling shape and size at nanometer scale. In the last few years, much work has been focused on the use of nano structures toward problems of biology and medicine. In this paper, we focus on the application of various nano structures and nano devices in clinical diagnostics and detection of important biological molecules. The discussion starts by introducing some basic techniques of micro-/nano scale fabrication that have enabled reproducible production of nano structures. The prospects, benefits, and limitations of using these novel techniques in the fields of bio detection and medical diagnostics are then discussed. Finally, the challenges of mass production and acceptance of nano technology by the medical community are considered.

Nuclear Reactions in Micro/Nano-Scale Metal Particles

International Nuclear Information System (INIS)

Kim, Y. E.

2013-01-01

Low-energy nuclear reactions in micro/nano-scale metal particles are described based on the theory of Bose-Einstein condensation nuclear fusion (BECNF). The BECNF theory is based on a single basic assumption capable of explaining the observed LENR phenomena; deuterons in metals undergo Bose-Einstein condensation. The BECNF theory is also a quantitative predictive physical theory. Experimental tests of the basic assumption and theoretical predictions are proposed. Potential application to energy generation by ignition at low temperatures is described. Generalized theory of BECNF is used to carry out theoretical analyses of recently reported experimental results for hydrogen-nickel system. (author)

Nuclear Reactions in Micro/Nano-Scale Metal Particles

Science.gov (United States)

Kim, Y. E.

2013-03-01

Low-energy nuclear reactions in micro/nano-scale metal particles are described based on the theory of Bose-Einstein condensation nuclear fusion (BECNF). The BECNF theory is based on a single basic assumption capable of explaining the observed LENR phenomena; deuterons in metals undergo Bose-Einstein condensation. The BECNF theory is also a quantitative predictive physical theory. Experimental tests of the basic assumption and theoretical predictions are proposed. Potential application to energy generation by ignition at low temperatures is described. Generalized theory of BECNF is used to carry out theoretical analyses of recently reported experimental results for hydrogen-nickel system.

Multi-scale coarse-graining for the study of assembly pathways in DNA-brick self-assembly

Science.gov (United States)

Fonseca, Pedro; Romano, Flavio; Schreck, John S.; Ouldridge, Thomas E.; Doye, Jonathan P. K.; Louis, Ard A.

2018-04-01

Inspired by recent successes using single-stranded DNA tiles to produce complex structures, we develop a two-step coarse-graining approach that uses detailed thermodynamic calculations with oxDNA, a nucleotide-based model of DNA, to parametrize a coarser kinetic model that can reach the time and length scales needed to study the assembly mechanisms of these structures. We test the model by performing a detailed study of the assembly pathways for a two-dimensional target structure made up of 334 unique strands each of which are 42 nucleotides long. Without adjustable parameters, the model reproduces a critical temperature for the formation of the assembly that is close to the temperature at which assembly first occurs in experiments. Furthermore, the model allows us to investigate in detail the nucleation barriers and the distribution of critical nucleus shapes for the assembly of a single target structure. The assembly intermediates are compact and highly connected (although not maximally so), and classical nucleation theory provides a good fit to the height and shape of the nucleation barrier at temperatures close to where assembly first occurs.

Nano-scale characterization of white layer in broached Inconel 718

Energy Technology Data Exchange (ETDEWEB)

Chen, Zhe, E-mail: zhe.chen@liu.se [Division of Engineering Materials, Linköping University, 58183 Linköping (Sweden); Colliander, Magnus Hörnqvist; Sundell, Gustav [Department of Physics, Chalmers University of Technology, 41296 Gothenburg (Sweden); Peng, Ru Lin [Division of Engineering Materials, Linköping University, 58183 Linköping (Sweden); Zhou, Jinming [Division of Production and Materials Engineering, Lund University, 22100 Lund (Sweden); Johansson, Sten; Moverare, Johan [Division of Engineering Materials, Linköping University, 58183 Linköping (Sweden)

2017-01-27

The formation mechanism of white layers during broaching and their mechanical properties are not well investigated and understood to date. In the present study, multiple advanced characterization techniques with nano-scale resolution, including transmission electron microscopy (TEM), transmission Kikuchi diffraction (TKD), atom probe tomography (APT) as well as nano-indentation, have been used to systematically examine the microstructural evolution and corresponding mechanical properties of a surface white layer formed when broaching the nickel-based superalloy Inconel 718. TEM observations showed that the broached white layer consists of nano-sized grains, mostly in the range of 20–50 nm. The crystallographic texture detected by TKD further revealed that the refined microstructure is primarily caused by strong shear deformation. Co-located Al-rich and Nb-rich fine clusters have been identified by APT, which are most likely to be γ′ and γ′′ clusters in a form of co-precipitates, where the clusters showed elongated and aligned appearance associated with the severe shearing history. The microstructural characteristics and crystallography of the broached white layer suggest that it was essentially formed by adiabatic shear localization in which the dominant metallurgical process is rotational dynamic recrystallization based on mechanically-driven subgrain rotations. The grain refinement within the white layer led to an increase of the surface nano-hardness by 14% and a reduction in elastic modulus by nearly 10% compared to that of the bulk material. This is primarily due to the greatly increased volume fraction of grain boundaries, when the grain size was reduced down to the nanoscale.

Volume changes at macro- and nano-scale in epoxy resins studied by PALS and PVT experimental techniques

Energy Technology Data Exchange (ETDEWEB)

Somoza, A. [IFIMAT-UNCentro, Pinto 399, B7000GHG Tandil (Argentina) and CICPBA, Pinto 399, B7000GHG Tandil (Argentina)]. E-mail: asomoza@exa.unicen.edu.ar; Salgueiro, W. [IFIMAT-UNCentro, Pinto 399, B7000GHG Tandil (Argentina); Goyanes, S. [LPMPyMC, Depto. de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellon I, 1428 Buenos Aires (Argentina); Ramos, J. [Materials and Technology Group, Departamento de Ingenieria Quimica y M. Ambiente, Escuela University Politecnica, Universidad Pais Vasco/Euskal Herriko Unibertsitatea, Pz. Europa 1, 20018 Donostia/San Sebastian (Spain); Mondragon, I. [Materials and Technology Group, Departamento de Ingenieria Quimica y M. Ambiente, Escuela University Politecnica, Universidad Pais Vasco/Euskal Herriko Unibertsitatea, Pz. Europa 1, 20018 Donostia/San Sebastian (Spain)

2007-02-15

A systematic study on changes in the volumes at macro- and nano-scale in epoxy systems cured with selected aminic hardeners at different pre-cure temperatures is presented. Free- and macroscopic specific-volumes were measured by PALS and pressure-volume-temperature techniques, respectively. An analysis of the relation existing between macro- and nano-scales of the thermosetting networks developed by the different chemical structures is shown. The result obtained indicates that the structure of the hardeners governs the packing of the molecular chains of the epoxy network.

Nano-scale structure in membranes in relation to enzyme action - computer simulation vs. experiment

DEFF Research Database (Denmark)

Høyrup, P.; Jørgensen, Kent; Mouritsen, O.G.

2002-01-01

There is increasing theoretical and experimental evidence indicating that small-scale domain structure and dynamical heterogeneity develop in lipid membranes as a consequence of the the underlying phase transitions and the associated density and composition fluctuations. The relevant coherence...... lengths are in the nano-meter range. The nano-scale structure is believed to be important for controlling the activity of enzymes, specifically phospholipases, which act at bilayer membranes. We propose here a lattice-gas statistical mechanical model with appropriate dynamics to account for the non......-equilibrium action of the enzyme phospholipase A(2) which hydrolyses lipid-bilayer substrates. The resulting product molecules are assumed to induce local variations in the membrane interfacial pressure. Monte Carlo simulations of the non-equilibrium properties of the model for one-component as well as binary lipid...

3D positioning scheme exploiting nano-scale IR-UWB orthogonal pulses.

Science.gov (United States)

Kim, Nammoon; Kim, Youngok

2011-10-04

In these days, the development of positioning technology for realizing ubiquitous environments has become one of the most important issues. The Global Positioning System (GPS) is a well-known positioning scheme, but it is not suitable for positioning in in-door/building environments because it is difficult to maintain line-of-sight condition between satellites and a GPS receiver. To such problem, various positioning methods such as RFID, WLAN, ZigBee, and Bluetooth have been developed for indoor positioning scheme. However, the majority of positioning schemes are focused on the two-dimension positioning even though three-dimension (3D) positioning information is more useful especially in indoor applications, such as smart space, U-health service, context aware service, etc. In this paper, a 3D positioning system based on mutually orthogonal nano-scale impulse radio ultra-wideband (IR-UWB) signals and cross array antenna is proposed. The proposed scheme uses nano-scale IR-UWB signals providing fine time resolution and high-resolution multiple signal specification algorithm for the time-of-arrival and the angle-of-arrival estimation. The performance is evaluated over various IEEE 802.15.4a channel models, and simulation results show the effectiveness of proposed scheme.

Modeling the Charge Transport in Graphene Nano Ribbon Interfaces for Nano Scale Electronic Devices

Science.gov (United States)

Kumar, Ravinder; Engles, Derick

2015-05-01

In this research work we have modeled, simulated and compared the electronic charge transport for Metal-Semiconductor-Metal interfaces of Graphene Nano Ribbons (GNR) with different geometries using First-Principle calculations and Non-Equilibrium Green's Function (NEGF) method. We modeled junctions of Armchair GNR strip sandwiched between two Zigzag strips with (Z-A-Z) and Zigzag GNR strip sandwiched between two Armchair strips with (A-Z-A) using semi-empirical Extended Huckle Theory (EHT) within the framework of Non-Equilibrium Green Function (NEGF). I-V characteristics of the interfaces were visualized for various transport parameters. The distinct changes in conductance and I-V curves reported as the Width across layers, Channel length (Central part) was varied at different bias voltages from -1V to 1 V with steps of 0.25 V. From the simulated results we observed that the conductance through A-Z-A graphene junction is in the range of 10-13 Siemens whereas the conductance through Z-A-Z graphene junction is in the range of 10-5 Siemens. These suggested conductance controlled mechanisms for the charge transport in the graphene interfaces with different geometries is important for the design of graphene based nano scale electronic devices like Graphene FETs, Sensors.

Design and construction of a DNA origami drug delivery system based on MPT64 antibody aptamer for tuberculosis treatment.

Science.gov (United States)

Ranjbar, Reza; Hafezi-Moghadam, Mohammad Sadegh

2016-02-01

With all of the developments on infectious diseases, tuberculosis (TB) remains a cause of death among people. One of the most promising assembly techniques in nano-technology is "scaffolded DNA origami" to design and construct a nano-scale drug delivery system. Because of the global health problems of tuberculosis, the development of potent new anti-tuberculosis drug delivery system without cross-resistance with known anti-mycobacterial agents is urgently needed. The aim of this study was to design a nano-scale drug delivery system for TB treatment using the DNA origami method. In this study, we presented an experimental research on a DNA drug delivery system for treating Tuberculosis. TEM images were visualized with an FEI Tecnai T12 BioTWIN at 120 kV. The model was designed by caDNAno software and computational prediction of the 3D solution shape and its flexibility was calculated with a CanDo server. Synthesizing the product was imaged using transmission electron microscopy after negative-staining by uranyl formate. We constructed a multilayer 3D DNA nanostructure system by designing square lattice geometry with the scaffolded-DNA-origami method. With changes in the lock and key sequences, we recommend that this system be used for other infectious diseases to target the pathogenic bacteria.

Nanometers to centimeters: novel optical nano-antennas, with an eye to scaled production

Science.gov (United States)

James, Timothy D.; Cadusch, Jasper J.; Earl, Stuart K.; Panchenko, Evgeniy; Mulvaney, Paul; Davis, Timothy J.; Roberts, Ann

2016-03-01

Optical nano-antennas have been the focus of intense research recently due to their ability to manipulate electromagnetic radiation on a subwavelength scale, and there is major interest in such devices for a wide variety of applications in photonics, sensing, and imaging. Significant effort has been put into developing highly compact, novel, next-generation light sources, which have great potential in realizing efficient sub-wavelength single photon sources and enhanced biological and chemical sensors. We have developed a number of innovative optical antenna designs including elements of chiral metasurfaces for enabling circularly polarized emission from quantum sources, new designs derived from Radio Frequency (RF) elements for quantum source enhancement and directionality, and nanostructures for investigating plasmonic dark-modes that have the ability to significantly reduce the Q-factor of nano-antennas. A challenge, however, remains the development of a scalable nanofabrication technology. The capacity to mass-produce nano-antennas will have a considerable impact on the commercial viability of these devices, and greatly improve research throughput. Here we present recent progress in the development of scalable fabrication strategies for producing of nano-antennas and antenna arrays, along with slot based plasmonic optical devices.

Scaling in nature: From DNA through heartbeats to weather

Science.gov (United States)

Havlin, S.; Buldyrev, S. V.; Bunde, A.; Goldberger, A. L.; Ivanov, P. Ch.; Peng, C.-K.; Stanley, H. E.

1999-12-01

The purpose of this talk is to describe some recent progress in applying scaling concepts to various systems in nature. We review several systems characterized by scaling laws such as DNA sequences, heartbeat rates and weather variations. We discuss the finding that the exponent α quantifying the scaling in DNA in smaller for coding than for noncoding sequences. We also discuss the application of fractal scaling analysis to the dynamics of heartbeat regulation, and report the recent finding that the scaling exponent α is smaller during sleep periods compared to wake periods. We also discuss the recent findings that suggest a universal scaling exponent characterizing the weather fluctuations.

DNA interaction studies of new nano metal based anticancer agent: validation by spectroscopic methods

International Nuclear Information System (INIS)

Tabassum, Sartaj; Chandra Sharma, Girish; Arjmand, Farukh; Azam, Ameer

2010-01-01

A new nano dimensional heterobimetallic Cu-Sn containing complex as a potential drug candidate was designed, synthesized and characterized by analytical and spectral methods. The electronic absorption and electron paramagnetic resonance parameters of the complex revealed that the Cu(II) ion exhibits a square pyramidal geometry with the two pyrazole nitrogen atoms, the amine nitrogen atom and the carboxylate oxygen of the phenyl glycine chloride ligand located at the equatorial sites and the coordinated chloride ion occupying an apical position. 119 Sn NMR spectral data showed a hexa-coordinated environment around the Sn(IV) metal ion. TEM, AFM and XRD measurements illustrate that the complex could induce the condensation of CT-DNA to a particulate nanostructure. The interaction of the Cu-Sn complex with CT-DNA was investigated by UV-vis absorption and emission spectroscopy, as well as cyclic voltammetric measurements. The results indicated that the complex interacts with DNA through an electrostatic mode of binding with an intrinsic binding constant K b = 8.42 x 10 4 M -1 . The Cu-Sn complex exhibits effective cleavage of pBR322 plasmid DNA by an oxidative cleavage mechanism, monitored at different concentrations both in the absence and in the presence of reducing agents.

DNA interaction studies of new nano metal based anticancer agent: validation by spectroscopic methods

Energy Technology Data Exchange (ETDEWEB)

Tabassum, Sartaj; Chandra Sharma, Girish; Arjmand, Farukh [Department of Chemistry, Aligarh Muslim University, Aligarh-202002 (India); Azam, Ameer [Center of Excellence in Materials Science (Nanomaterials), Department of Applied Physics, Aligarh Muslim University, Aligarh 202002, UP (India)

2010-05-14

A new nano dimensional heterobimetallic Cu-Sn containing complex as a potential drug candidate was designed, synthesized and characterized by analytical and spectral methods. The electronic absorption and electron paramagnetic resonance parameters of the complex revealed that the Cu(II) ion exhibits a square pyramidal geometry with the two pyrazole nitrogen atoms, the amine nitrogen atom and the carboxylate oxygen of the phenyl glycine chloride ligand located at the equatorial sites and the coordinated chloride ion occupying an apical position. {sup 119}Sn NMR spectral data showed a hexa-coordinated environment around the Sn(IV) metal ion. TEM, AFM and XRD measurements illustrate that the complex could induce the condensation of CT-DNA to a particulate nanostructure. The interaction of the Cu-Sn complex with CT-DNA was investigated by UV-vis absorption and emission spectroscopy, as well as cyclic voltammetric measurements. The results indicated that the complex interacts with DNA through an electrostatic mode of binding with an intrinsic binding constant K{sub b} = 8.42 x 10{sup 4} M{sup -1}. The Cu-Sn complex exhibits effective cleavage of pBR322 plasmid DNA by an oxidative cleavage mechanism, monitored at different concentrations both in the absence and in the presence of reducing agents.

HBV-Specific shRNA is Capable of Reducing the Formation of Hepatitis B Virus Covalently Closed Circular DNA, but has No Effect on Established Covalently Closed Circular DNA in vitro

OpenAIRE

Starkey, Jason L.; Chiari, Estelle F.; Isom, Harriet C.

2009-01-01

Hepatitis B virus (HBV) covalently closed circular DNA (CCC DNA) is the source of HBV transcripts and persistence in chronically infected patients. The novel aspect of this study was to determine the effect of RNA interference (RNAi) on HBV CCC DNA when administered prior to establishment of HBV replication or during chronic HBV infection. HBV replication was initiated in HepG2 cells by transduction with HBV baculovirus. Subculture of HBV expressing HepG2 cells at 10 days post-transduction ge...

Reduced wear of enamel with novel fine and nano-scale leucite glass-ceramics.

Science.gov (United States)

Theocharopoulos, Antonios; Chen, Xiaohui; Hill, Robert; Cattell, Michael J

2013-06-01

Leucite glass-ceramics used to produce all-ceramic restorations can suffer from brittle fracture and wear the opposing teeth. High strength and fine crystal sized leucite glass-ceramics have recently been reported. The objective of this study is to investigate whether fine and nano-scale leucite glass-ceramics with minimal matrix microcracking are associated with a reduction in in vitro tooth wear. Human molar cusps (n=12) were wear tested using a Bionix-858 testing machine (300,000 simulated masticatory cycles) against experimental fine crystal sized (FS), nano-scale crystal sized (NS) leucite glass-ceramics and a commercial leucite glass-ceramic (Ceramco-3, Dentsply, USA). Wear was imaged using Secondary Electron Imaging (SEI) and quantified using white-light profilometry. Both experimental groups were found to produce significantly (pceramic) loss than the FS group. Increased waviness and damage was observed on the wear surfaces of the Ceramco-3 glass-ceramic disc/tooth group in comparison to the experimental groups. This was also indicated by higher surface roughness values for the Ceramco-3 glass-ceramic disc/tooth group. Fine and nano-sized leucite glass-ceramics produced a reduction in in vitro tooth wear. The high strength low wear materials of this study may help address the many problems associated with tooth enamel wear and restoration failure. Copyright © 2013 Elsevier Ltd. All rights reserved.

The viability and performance characterization of nano scale energetic materials on a semiconductor bridge (SCB)

Science.gov (United States)

Strohm, Gianna Sophia

The move from conventional energetic composites to nano scale energetic mixtures (nano energetics) has shown dramatic improvement in energy release rate and sensitivity to ignition. A possible application of nano energetics is on a semiconductor bridge (SCB). An SCB typically requires a tenth of the energy input as compared to a bridge wire design with the same no-fire and is capable of igniting in tens of microseconds. For very low energy applications, SCBs can be manufactured to extremely small sizes and it is necessary to find materials with particle sizes that are even smaller to function. Reactive particles of comparable size to the bridge can lead to problems with ignition reliability for small bridges. Nano-energetic composites and the use of SCBs have been significantly studied individually, however, the process of combining nano energetics with an SCB has not been investigated extensively and is the focus of this work. Goals of this study are to determine if nano energetics can be used with SCBs to further reduce the minimum energy required and improve reliability. The performance of nano-scale aluminum (nAl) and bismuth oxide (Bi2O3) with nitrocellulose (NC), Fluorel(TM) FC 2175 (chemically equivalent to VitonRTM) and Glycidyl Azide Polymer (GAP) as binders where quantified initially using the SenTest(TM) algorithm at three weight fractions (5, 7, and 9%) of binder. The threshold energy was calculated and compared to previous data using conventional materials such as zirconium potassium chlorate (ZPC), mercuric 5-Nitrotetrazol (DXN-1) and titanium sub-hydride potassium per-chlorate (TSPP). It was found that even though there where only slight differences in performance between the binders with nAl/Bi2O 3 at any of the three binder weight fractions, the results show that these nano energetic materials require about half of the threshold energy compared to conventional materials using an SCB with an 84x42 mum bridge. Binder limit testing was conducted to

Nano-scaled chalcogenide-based memories

International Nuclear Information System (INIS)

Redaelli, Andrea; Pirovano, Agostino

2011-01-01

Today phase change memory (PCM) technology has reached product maturity at 90 and 65 nm nodes, while the 45 nm node is under development and is expected to enter in the market soon. The continuous decrease of the cell size with scaling leads to an effective active area as small as 150 nm 2 and an active volume involved in the phase transformation of about 10 4 nm 3 , thus entering definitively into the nanotechnology world. At this extremely reduced dimension, the reliability of the device must be carefully investigated. In this work we show that the cycling performance of the device is well maintained, not being a problem for either the bipolar transistor or the storage element. The phase transition from the amorphous to the crystalline state is, of course, one of the most interesting phenomena, impacting cell retention capability and device performance. The stochastic nature of nano-nuclei percolation in the amorphous matrix is shown as an important ingredient in the retention of PCM devices. The related dispersion in crystallization times is analyzed through a crystallization Monte Carlo model and a physical insight into nucleation and growth mechanisms is provided.

3D positioning scheme exploiting nano-scale IR-UWB orthogonal pulses

Directory of Open Access Journals (Sweden)

Kim Nammoon

2011-01-01

Full Text Available Abstract In these days, the development of positioning technology for realizing ubiquitous environments has become one of the most important issues. The Global Positioning System (GPS is a well-known positioning scheme, but it is not suitable for positioning in in-door/building environments because it is difficult to maintain line-of-sight condition between satellites and a GPS receiver. To such problem, various positioning methods such as RFID, WLAN, ZigBee, and Bluetooth have been developed for indoor positioning scheme. However, the majority of positioning schemes are focused on the two-dimension positioning even though three-dimension (3D positioning information is more useful especially in indoor applications, such as smart space, U-health service, context aware service, etc. In this paper, a 3D positioning system based on mutually orthogonal nano-scale impulse radio ultra-wideband (IR-UWB signals and cross array antenna is proposed. The proposed scheme uses nano-scale IR-UWB signals providing fine time resolution and high-resolution multiple signal specification algorithm for the time-of-arrival and the angle-of-arrival estimation. The performance is evaluated over various IEEE 802.15.4a channel models, and simulation results show the effectiveness of proposed scheme.

Field-induced Gap and Quantized Charge Pumping in Nano-helix

Energy Technology Data Exchange (ETDEWEB)

Qi, Xiao-Liang; /Stanford U., Phys. Dept. /Tsinghua U., Beijing; Zhang, Shou-Cheng; /Stanford U., Phys. Dept.

2010-02-15

We propose several novel physical phenomena based on nano-scale helical wires. Applying a static electric field transverse to the helical wire induces a metal to insulator transition, with the band gap determined by the applied voltage. Similar idea can be applied to 'geometrically' constructing one-dimensional systems with arbitrary external potential. With a quadrupolar electrode configuration, the electric field could rotate in the transverse plane, leading to a quantized dc charge current proportional to the frequency of the rotation. Such a device could be used as a new standard for the high precession measurement of the electric current. The inverse effect implies that passing an electric current through a helical wire in the presence of a transverse static electric field can lead to a mechanical rotation of the helix. This effect can be used to construct nano-scale electro-mechanical motors. Finally, our methodology also enables new ways of controlling and measuring the electronic properties of helical biological molecules such as the DNA.

Pathological mechanisms underlying single large‐scale mitochondrial DNA deletions

Science.gov (United States)

Rocha, Mariana C.; Rosa, Hannah S.; Grady, John P.; Blakely, Emma L.; He, Langping; Romain, Nadine; Haller, Ronald G.; Newman, Jane; McFarland, Robert; Ng, Yi Shiau; Gorman, Grainne S.; Schaefer, Andrew M.; Tuppen, Helen A.; Taylor, Robert W.

2018-01-01

Objective Single, large‐scale deletions in mitochondrial DNA (mtDNA) are a common cause of mitochondrial disease. This study aimed to investigate the relationship between the genetic defect and molecular phenotype to improve understanding of pathogenic mechanisms associated with single, large‐scale mtDNA deletions in skeletal muscle. Methods We investigated 23 muscle biopsies taken from adult patients (6 males/17 females with a mean age of 43 years) with characterized single, large‐scale mtDNA deletions. Mitochondrial respiratory chain deficiency in skeletal muscle biopsies was quantified by immunoreactivity levels for complex I and complex IV proteins. Single muscle fibers with varying degrees of deficiency were selected from 6 patient biopsies for determination of mtDNA deletion level and copy number by quantitative polymerase chain reaction. Results We have defined 3 “classes” of single, large‐scale deletion with distinct patterns of mitochondrial deficiency, determined by the size and location of the deletion. Single fiber analyses showed that fibers with greater respiratory chain deficiency harbored higher levels of mtDNA deletion with an increase in total mtDNA copy number. For the first time, we have demonstrated that threshold levels for complex I and complex IV deficiency differ based on deletion class. Interpretation Combining genetic and immunofluorescent assays, we conclude that thresholds for complex I and complex IV deficiency are modulated by the deletion of complex‐specific protein‐encoding genes. Furthermore, removal of mt‐tRNA genes impacts specific complexes only at high deletion levels, when complex‐specific protein‐encoding genes remain. These novel findings provide valuable insight into the pathogenic mechanisms associated with these mutations. Ann Neurol 2018;83:115–130 PMID:29283441

Strengthening effect of nano-scale precipitates in a die-cast Mg–4Al–5.6Sm–0.3Mn alloy

Energy Technology Data Exchange (ETDEWEB)

Yang, Qiang [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Bu, Fanqiang [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Qiu, Xin [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Yangzhou Hongfu Aluminium Co. Ltd, Yangzhou 100049 (China); Li, Yangde; Li, Weirong [E-ande Scientific & Technology Co. Ltd, Dongguan 523000 (China); Sun, Wei [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Liu, Xiaojuan, E-mail: lxjuan@ciac.ac.cn [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Meng, Jian, E-mail: jmeng@ciac.jl.cn [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China)

2016-04-25

In this paper we report a quantitative study of the age-hardening in the high-pressure die-cast Mg–4Al−5.6Sm−0.3Mn alloy. The results indicate that a number of nano-scale spherical precipitates identified as Al{sub 3}Sm using high-angle annular dark-field scanning transmission electron microscopy, precipitated in Mg matrix after aging at 150–225 °C, with no obvious changes on grain sizes, intermetallic phases formed during solidification, and dislocation densities. From the existing strengthening theory equations in which some lacking parameters were taken from the first-principles density functional theory (DFT) calculations, a quantitative insight into the strengthening mechanisms of the nano-scale precipitate was formulated. The results are in reasonable agreement with the experimental values, and the operative mechanism of precipitation strengthening was revealed as Orowan dislocation bypassing. - Highlights: • The yield strength of Mg–Al–Sm alloy was improved by aging treatment. • A number of nano-scale precipitates formed in matrix after aging treatments. • The nanoscale precipitate was confirmed as Al{sub 3}Sm based on the data of HAADF-STEM study. • The strengthening mechanisms of the nano-scale precipitate were quantitatively formulated. • The operative mechanism of precipitate strengthening is Orowan dislocation bypassing.

Ignition dynamics and activation energies of metallic thermites: From nano- to micron-scale particulate composites

Science.gov (United States)

Hunt, Emily M.; Pantoya, Michelle L.

2005-08-01

Ignition behaviors associated with nano- and micron-scale particulate composite thermites were studied experimentally and modeled theoretically. The experimental analysis utilized a CO2 laser ignition apparatus to ignite the front surface of compacted nickel (Ni) and aluminum (Al) pellets at varying heating rates. Ignition delay time and ignition temperature as a function of both Ni and Al particle size were measured using high-speed imaging and microthermocouples. The apparent activation energy was determined from this data using a Kissinger isoconversion method. This study shows that the activation energy is significantly lower for nano- compared with micron-scale particulate media (i.e., as low as 17.4 compared with 162.5kJ /mol, respectively). Two separate Arrhenius-type mathematical models were developed that describe ignition in the nano- and the micron-composite thermites. The micron-composite model is based on a heat balance while the nanocomposite model incorporates the energy of phase transformation in the alumina shell theorized to be an initiating step in the solid-solid diffusion reaction and uniquely appreciable in nanoparticle media. These models were found to describe the ignition of the Ni /Al alloy for a wide range of heating rates.

Investigations on a nano-scale periodical waveguide structure taking surface plasmon polaritons into consideration

International Nuclear Information System (INIS)

Liu Weihao; Zhong Renbin; Zhou Jun; Zhang Yaxin; Hu Min; Liu Shenggang

2012-01-01

Detailed theoretical analysis and computer simulations on the electromagnetic characteristics of a nano-scale periodical waveguide structure, taking surface plasmon polaritons (SPPs) into consideration, are carried out in this paper. The results show that SPPs will significantly influence the electromagnetic characteristics of the structure. When the operation frequency is in a certain band—the ‘radial confinement band’, neither radial surface plasmon waves nor guided waves, which both will lead to radial energy loss, can be excited in the structure. And the electromagnetic waves are completely confined within the longitudinal waveguide and propagate along it with little attenuation. The radial energy loss is then significantly reduced. These results are of great significance not only for increasing the efficiency of the radiation sources based on the nano-scale periodical waveguide structure but also for the development of high-efficiency waveguides and wide-band filters in the infrared and visible light regimes. (paper)

Feasibility of Pb phytoextraction using nano-materials assisted ryegrass: Results of a one-year field-scale experiment.

Science.gov (United States)

Liang, Shu-Xuan; Jin, Yu; Liu, Wei; Li, Xiliang; Shen, Shi-Gang; Ding, Ling

2017-04-01

The effect of the combined application of nano-hydroxyapatite (NHAP) or nano-carbon black (NCB) on the phytoextraction of Pb by ryegrass was investigated as an enhanced remediation technique for soils by field-scale experiment. After the addition of 0.2% NHAP or NCB to the soil, temporal variation of the uptake of Pb in aboveground parts and roots were observed. Ryegrass shoot concentrations of Pb were lower with nano-materials application than without nano-materials for the first month. However, the shoot concentrations of Pb were significantly increased with nano-materials application, in particular NHAP groups. The ryegrass root concentrations of Pb were lower with nano-materials application for the first month. These results indicated that nano-materials had significant effects on stabilization of lead, especially at the beginning of the experiment. Along with the experimental proceeding, phytotoxicity was alleviated after the incorporation of nano-materials. The ryegrass biomass was significantly higher with nano-materials application. Consequently, the Pb phytoextraction potential of ryegrass significantly increased with nano-materials application compared to the gounps without nano-materials application. The total removal rates of soil Pb were higher after combined application of NHAP than NCB. NHAP is more suitable than NCB for in-situ remediation of Pb-contaminated soils. The ryegrass translocation factor exhibited a marked increase with time. It was thought that the major role of NHP and NBA might be to alleviate the Pb phytotoxicity and increase biomass of plants. Copyright © 2016 Elsevier Ltd. All rights reserved.

Cytology of DNA Replication Reveals Dynamic Plasticity of Large-Scale Chromatin Fibers.

Science.gov (United States)

Deng, Xiang; Zhironkina, Oxana A; Cherepanynets, Varvara D; Strelkova, Olga S; Kireev, Igor I; Belmont, Andrew S

2016-09-26

In higher eukaryotic interphase nuclei, the 100- to >1,000-fold linear compaction of chromatin is difficult to reconcile with its function as a template for transcription, replication, and repair. It is challenging to imagine how DNA and RNA polymerases with their associated molecular machinery would move along the DNA template without transient decondensation of observed large-scale chromatin "chromonema" fibers [1]. Transcription or "replication factory" models [2], in which polymerases remain fixed while DNA is reeled through, are similarly difficult to conceptualize without transient decondensation of these chromonema fibers. Here, we show how a dynamic plasticity of chromatin folding within large-scale chromatin fibers allows DNA replication to take place without significant changes in the global large-scale chromatin compaction or shape of these large-scale chromatin fibers. Time-lapse imaging of lac-operator-tagged chromosome regions shows no major change in the overall compaction of these chromosome regions during their DNA replication. Improved pulse-chase labeling of endogenous interphase chromosomes yields a model in which the global compaction and shape of large-Mbp chromatin domains remains largely invariant during DNA replication, with DNA within these domains undergoing significant movements and redistribution as they move into and then out of adjacent replication foci. In contrast to hierarchical folding models, this dynamic plasticity of large-scale chromatin organization explains how localized changes in DNA topology allow DNA replication to take place without an accompanying global unfolding of large-scale chromatin fibers while suggesting a possible mechanism for maintaining epigenetic programming of large-scale chromatin domains throughout DNA replication. Copyright © 2016 Elsevier Ltd. All rights reserved.

Self-Assembly, Pattern Formation and Growth Phenomena in Nano-Systems

CERN Document Server

Nepomnyashchy, Alexander A

2006-01-01

Nano-science and nano-technology are rapidly developing scientific and technological areas that deal with physical, chemical and biological processes that occur on nano-meter scale – one millionth of a millimeter. Self-organization and pattern formation play crucial role on nano-scales and promise new, effective routes to control various nano-scales processes. This book contains lecture notes written by the lecturers of the NATO Advanced Study Institute "Self-Assembly, Pattern Formation and Growth Phenomena in Nano-Systems" that took place in St Etienne de Tinee, France, in the fall 2004. They give examples of self-organization phenomena on micro- and nano-scale as well as examples of the interplay between phenomena on nano- and macro-scales leading to complex behavior in various physical, chemical and biological systems. They discuss such fascinating nano-scale self-organization phenomena as self-assembly of quantum dots in thin solid films, pattern formation in liquid crystals caused by light, self-organi...

Controlled fabrication of nano-scale double barrier magnetic tunnel junctions using focused ion beam milling method

International Nuclear Information System (INIS)

Wei, H.X.; Wang, T.X.; Zeng, Z.M.; Zhang, X.Q.; Zhao, J.; Han, X.F.

2006-01-01

The controlled fabrication method for nano-scale double barrier magnetic tunnel junctions (DBMTJs) with the layer structure of Ta(5)/Cu(10)/Ni 79 Fe 21 (5)/Ir 22 Mn 78 (12)/Co 6 Fe 2 B 2 (4)/Al(1) -oxide/Co 6 Fe 2 B 2 (6)/Al (1)-oxide/Co 6 Fe 2 B 2 (4)/Ir 22 Mn 78 (12)/Ni 79 Fe 21 (5)/Ta(5) (thickness unit: nm) was used. This method involved depositing thin multi-layer stacks by sputtering system, and depositing a Pt nano-pillar using a focused ion beam which acted both as a top contact and as an etching mask. The advantages of this process over the traditional process using e-beam and optical lithography in that it involve only few processing steps, e.g. it does not involve any lift-off steps. In order to evaluate the nanofabrication techniques, the DBMTJs with the dimensions of 200 nmx400 nm, 200 nmx200 nm nano-scale were prepared and their R-H, I-V characteristics were measured.

Preparation of Nano-Scale Biopolymer Extracted from Coconut Residue and Its Performance as Drag Reducing Agent (DRA

Directory of Open Access Journals (Sweden)

Hasan Muhammad Luqman Bin

2017-01-01

Full Text Available Drag or frictional force is defined as force that acts opposite to the object’s relative motion through a fluid which then will cause frictional pressure loss in the pipeline. Drag Reducing Agent (DRA is used to solve this issue and most of the DRAs are synthetic polymers but has some environmental issues. Therefore for this study, biopolymer known as Coconut Residue (CR is selected as the candidate to replace synthetic polymers DRA. The objective of this study is to evaluate the effectiveness of Nano-scale biopolymer DRA on the application of water injection system. Carboxymethyl cellulose (CMC is extracted by synthesizing the cellulose extracted from CR under the alkali-catalyzed reaction using monochloroacetic acid. The synthesize process is held in controlled condition whereby the concentration of NaOH is kept at 60%wt, 60 °C temperature and the reaction time is 4 hours. For every 25 g of dried CR used, the mass of synthesized CMC yield is at an average of 23.8 g. The synthesized CMC is then grinded in controlled parameters using the ball milling machine to get the Nano-scale size. The particle size obtained from this is 43.32 Nm which is in range of Nano size. This study proved that Nano-size CMC has higher percentage of drag reduction (%DR and flow increase (%FI if compared to normal-size CMC when tested in high and low flow rate; 44% to 48% increase in %DR and %FI when tested in low flow rate, and 16% to 18% increase in %DR and %FI when tested in high flow rate. The success of this research shows that Nano-scale DRA can be considered to be used to have better performance in reducing drag.

Computational optimization of catalyst distributions at the nano-scale

International Nuclear Information System (INIS)

Ström, Henrik

2017-01-01

Highlights: • Macroscopic data sampled from a DSMC simulation contain statistical scatter. • Simulated annealing is evaluated as an optimization algorithm with DSMC. • Proposed method is more robust than a gradient search method. • Objective function uses the mass transfer rate instead of the reaction rate. • Combined algorithm is more efficient than a macroscopic overlay method. - Abstract: Catalysis is a key phenomenon in a great number of energy processes, including feedstock conversion, tar cracking, emission abatement and optimizations of energy use. Within heterogeneous, catalytic nano-scale systems, the chemical reactions typically proceed at very high rates at a gas–solid interface. However, the statistical uncertainties characteristic of molecular processes pose efficiency problems for computational optimizations of such nano-scale systems. The present work investigates the performance of a Direct Simulation Monte Carlo (DSMC) code with a stochastic optimization heuristic for evaluations of an optimal catalyst distribution. The DSMC code treats molecular motion with homogeneous and heterogeneous chemical reactions in wall-bounded systems and algorithms have been devised that allow optimization of the distribution of a catalytically active material within a three-dimensional duct (e.g. a pore). The objective function is the outlet concentration of computational molecules that have interacted with the catalytically active surface, and the optimization method used is simulated annealing. The application of a stochastic optimization heuristic is shown to be more efficient within the present DSMC framework than using a macroscopic overlay method. Furthermore, it is shown that the performance of the developed method is superior to that of a gradient search method for the current class of problems. Finally, the advantages and disadvantages of different types of objective functions are discussed.

Nano-hydroxyapatite modulates osteoblast lineage commitment by stimulation of DNA methylation and regulation of gene expression

Science.gov (United States)

Ha, Shin-Woo; Jang, Hae Lin; Nam, Ki Tae; Beck, George R.

2015-01-01

Hydroxyapatite (HA) is the primary structural component of the skeleton and dentition. Under biological conditions, HA does not occur spontaneously and therefore must be actively synthesized by mineralizing cells such as osteoblasts. The mechanism(s) by which HA is actively synthesized by cells and deposited to create a mineralized matrix are not fully understood and the consequences of mineralization on cell function are even less well understood. HA can be chemically synthesized (HAp) and is therefore currently being investigated as a promising therapeutic biomaterial for use as a functional scaffold and implant coating for skeletal repair and dental applications. Here we investigated the biological effects of nano-HAp (10×100 nm) on the lineage commitment and differentiation of bone forming osteoblasts. Exposure of early stage differentiating osteoblasts resulted in dramatic and sustained changes in gene expression, both increased and decreased, whereas later stage osteoblasts were much less responsive. Analysis of the promoter region one of the most responsive genes, alkaline phosphatase, identified the stimulation of DNA methylation following cell exposure to nano-HAp. Collectively, the results reveal the novel epigenetic regulation of cell function by nano-HAp which has significant implication on lineage determination as well as identifying a novel potential therapeutic use of nanomaterials. PMID:26141836

Evaporation of Liquid Droplet in Nano and Micro Scales from Statistical Rate Theory.

Science.gov (United States)

Duan, Fei; He, Bin; Wei, Tao

2015-04-01

The statistical rate theory (SRT) is applied to predict the average evaporation flux of liquid droplet after the approach is validated in the sessile droplet experiments of the water and heavy water. The steady-state experiments show a temperature discontinuity at the evaporating interface. The average evaporation flux is evaluated by individually changing the measurement at a liquid-vapor interface, including the interfacial liquid temperature, the interfacial vapor temperature, the vapor-phase pressure, and the droplet size. The parameter study shows that a higher temperature jump would reduce the average evaporation flux. The average evaporation flux can significantly be influenced by the interfacial liquid temperature and the vapor-phase pressure. The variation can switch the evaporation into condensation. The evaporation flux is found to remain relative constant if the droplet is larger than a micro scale, while the smaller diameters in nano scale can produce a much higher evaporation flux. In addition, a smaller diameter of droplets with the same liquid volume has a larger surface area. It is suggested that the evaporation rate increases dramatically as the droplet shrinks into nano size.

Thermoelectric effect in nano-scaled lanthanides doped ZnO

Energy Technology Data Exchange (ETDEWEB)

Otal, E H; Canepa, H R; Walsoee de Reca, N E [Centro de Investigacion en Solidos, CITEFA, San Juan Bautista de La Salle 4397 (B1603ALO) Villa Martelli, Buenos Aires (Argentina); Schaeuble, N; Aguirre, M H, E-mail: canepa@citefa.gov.a, E-mail: myriam.aguirre@empa.c [Solid State Chemistry and Catalysis, Empa, Swiss Federal Laboratories for Materials Testing and Research, Ueberlandstrasse 129, CH-8600 Duebendorf (Switzerland)

2009-05-01

Start Nano-scaled ZnO with 1% Er doping was prepared by soft chemistry methods. The synthesis was carried out in anhydrous polar solvent to achieve a crystal size of a few nanometers. Resulting particles were processed as precipitates or multi layer films. Structural characterization was evaluated by X-Ray diffraction and transmission and scanning electron microscopy. In the case of films, UV-Vis characterization was made. The thermoelectrical properties of ZnO:Er were evaluated and compared with a typical good thermoelectric material ZnO:Al. Both materials have also shown high Seebeck coefficients and they can be considered as potential compounds for thermoelectric conversion.

Microstructure Charaterization of a Hardened and Tempered Tool Steel: from Macro to Nano Scale

DEFF Research Database (Denmark)

Højerslev, Christian; Somers, Marcel A. J.; Carstensen, Jesper V.

2002-01-01

The microstructure of a conventionally heat treated PM AISI M3:2 tool steel, was characterised by a combination of light optical and electron microscopy, covering the range from micro to nano scale. Dilatometry and X-ray diffractometry were used for an overall macro characterisation of the phases...

Multi-scale analysis of the effect of nano-filler particle diameter on the physical properties of CAD/CAM composite resin blocks.

Science.gov (United States)

Yamaguchi, Satoshi; Inoue, Sayuri; Sakai, Takahiko; Abe, Tomohiro; Kitagawa, Haruaki; Imazato, Satoshi

2017-05-01

The objective of this study was to assess the effect of silica nano-filler particle diameters in a computer-aided design/manufacturing (CAD/CAM) composite resin (CR) block on physical properties at the multi-scale in silico. CAD/CAM CR blocks were modeled, consisting of silica nano-filler particles (20, 40, 60, 80, and 100 nm) and matrix (Bis-GMA/TEGDMA), with filler volume contents of 55.161%. Calculation of Young's moduli and Poisson's ratios for the block at macro-scale were analyzed by homogenization. Macro-scale CAD/CAM CR blocks (3 × 3 × 3 mm) were modeled and compressive strengths were defined when the fracture loads exceeded 6075 N. MPS values of the nano-scale models were compared by localization analysis. As the filler size decreased, Young's moduli and compressive strength increased, while Poisson's ratios and MPS decreased. All parameters were significantly correlated with the diameters of the filler particles (Pearson's correlation test, r = -0.949, 0.943, -0.951, 0.976, p CAD/CAM CR blocks can be enhanced by loading silica nanofiller particles of smaller diameter. CAD/CAM CR blocks by using smaller silica nano-filler particles have a potential to increase fracture resistance.

Rectangular coordination polymer nanoplates: large-scale, rapid synthesis and their application as a fluorescent sensing platform for DNA detection.

Directory of Open Access Journals (Sweden)

Yingwei Zhang

Full Text Available In this paper, we report on the large-scale, rapid synthesis of uniform rectangular coordination polymer nanoplates (RCPNs assembled from Cu(II and 4,4'-bipyridine for the first time. We further demonstrate that such RCPNs can be used as a very effective fluorescent sensing platform for multiple DNA detection with a detection limit as low as 30 pM and a high selectivity down to single-base mismatch. The DNA detection is accomplished by the following two steps: (1 RCPN binds dye-labeled single-stranded DNA (ssDNA probe, which brings dye and RCPN into close proximity, leading to fluorescence quenching; (2 Specific hybridization of the probe with its target generates a double-stranded DNA (dsDNA which detaches from RCPN, leading to fluorescence recovery. It suggests that this sensing system can well discriminate complementary and mismatched DNA sequences. The exact mechanism of fluorescence quenching involved is elucidated experimentally and its use in a human blood serum system is also demonstrated successfully.

Long-term superelastic cycling at nano-scale in Cu-Al-Ni shape memory alloy micropillars

Energy Technology Data Exchange (ETDEWEB)

San Juan, J., E-mail: jose.sanjuan@ehu.es; Gómez-Cortés, J. F. [Dpto. Física Materia Condensada, Facultad de Ciencia y Tecnología, Univ. del País Vasco UPV/EHU, Apdo. 644, 48080 Bilbao (Spain); López, G. A.; Nó, M. L. [Dpto. Física Aplicada II, Facultad de Ciencia y Tecnología, Univ. del País Vasco UPV/EHU, Apdo. 644, 48080 Bilbao (Spain); Jiao, C. [FEI, Achtseweg Noord 5, 5651 GG Eindhoven (Netherlands)

2014-01-06

Superelastic behavior at nano-scale has been studied along cycling in Cu-Al-Ni shape memory alloy micropillars. Arrays of square micropillars were produced by focused ion beam milling, on slides of [001] oriented Cu-Al-Ni single crystals. Superelastic behavior of micropillars, due to the stress-induced martensitic transformation, has been studied by nano-compression tests during thousand cycles, and its evolution has been followed along cycling. Each pillar has undergone more than thousand cycles without any detrimental evolution. Moreover, we demonstrate that after thousand cycles they exhibit a perfectly reproducible and completely recoverable superelastic behavior.

Nano-Scale Sample Acquisition Systems for Small Class Exploration Spacecraft

Science.gov (United States)

Paulsen, G.

2015-12-01

The paradigm for space exploration is changing. Large and expensive missions are very rare and the space community is turning to smaller, lighter, and less expensive missions that could still perform great exploration. These missions are also within reach of commercial companies such as the Google Lunar X Prize teams that develop small scale lunar missions. Recent commercial endeavors such as "Planet Labs inc." and Sky Box Imaging, inc. show that there are new benefits and business models associated with miniaturization of space hardware. The Nano-Scale Sample Acquisition System includes NanoDrill for capture of small rock cores and PlanetVac for capture of surface regolith. These two systems are part of the ongoing effort to develop "Micro Sampling" systems for deployment by the small spacecraft with limited payload capacities. The ideal applications include prospecting missions to the Moon and Asteroids. The MicroDrill is a rotary-percussive coring drill that captures cores 7 mm in diameter and up to 2 cm long. The drill weighs less than 1 kg and can capture a core from a 40 MPa strength rock within a few minutes, with less than 10 Watt power and less than 10 Newton of preload. The PlanetVac is a pneumatic based regolith acquisition system that can capture surface sample in touch-and-go maneuver. These sampling systems were integrated within the footpads of commercial quadcopter for testing. As such, they could also be used by geologists on Earth to explore difficult to get to locations.

Advanced Ceramics from Preceramic Polymers Modified at the Nano-Scale: A Review

Directory of Open Access Journals (Sweden)

Enrico Bernardo

2014-03-01

Full Text Available Preceramic polymers, i.e., polymers that are converted into ceramics upon heat treatment, have been successfully used for almost 40 years to give advanced ceramics, especially belonging to the ternary SiCO and SiCN systems or to the quaternary SiBCN system. One of their main advantages is the possibility of combining the shaping and synthesis of ceramics: components can be shaped at the precursor stage by conventional plastic-forming techniques, such as spinning, blowing, injection molding, warm pressing and resin transfer molding, and then converted into ceramics by treatments typically above 800 °C. The extension of the approach to a wider range of ceramic compositions and applications, both structural and thermo-structural (refractory components, thermal barrier coatings or functional (bioactive ceramics, luminescent materials, mainly relies on modifications of the polymers at the nano-scale, i.e., on the introduction of nano-sized fillers and/or chemical additives, leading to nano-structured ceramic components upon thermal conversion. Fillers and additives may react with the main ceramic residue of the polymer, leading to ceramics of significant engineering interest (such as silicates and SiAlONs, or cause the formation of secondary phases, significantly affecting the functionalities of the polymer-derived matrix.

Advanced Ceramics from Preceramic Polymers Modified at the Nano-Scale: A Review.

Science.gov (United States)

Bernardo, Enrico; Fiocco, Laura; Parcianello, Giulio; Storti, Enrico; Colombo, Paolo

2014-03-06

Preceramic polymers, i.e. , polymers that are converted into ceramics upon heat treatment, have been successfully used for almost 40 years to give advanced ceramics, especially belonging to the ternary SiCO and SiCN systems or to the quaternary SiBCN system. One of their main advantages is the possibility of combining the shaping and synthesis of ceramics: components can be shaped at the precursor stage by conventional plastic-forming techniques, such as spinning, blowing, injection molding, warm pressing and resin transfer molding, and then converted into ceramics by treatments typically above 800 °C. The extension of the approach to a wider range of ceramic compositions and applications, both structural and thermo-structural (refractory components, thermal barrier coatings) or functional (bioactive ceramics, luminescent materials), mainly relies on modifications of the polymers at the nano-scale, i.e. , on the introduction of nano-sized fillers and/or chemical additives, leading to nano-structured ceramic components upon thermal conversion. Fillers and additives may react with the main ceramic residue of the polymer, leading to ceramics of significant engineering interest (such as silicates and SiAlONs), or cause the formation of secondary phases, significantly affecting the functionalities of the polymer-derived matrix.

Advanced Ceramics from Preceramic Polymers Modified at the Nano-Scale: A Review

Science.gov (United States)

Bernardo, Enrico; Fiocco, Laura; Parcianello, Giulio; Storti, Enrico; Colombo, Paolo

2014-01-01

Preceramic polymers, i.e., polymers that are converted into ceramics upon heat treatment, have been successfully used for almost 40 years to give advanced ceramics, especially belonging to the ternary SiCO and SiCN systems or to the quaternary SiBCN system. One of their main advantages is the possibility of combining the shaping and synthesis of ceramics: components can be shaped at the precursor stage by conventional plastic-forming techniques, such as spinning, blowing, injection molding, warm pressing and resin transfer molding, and then converted into ceramics by treatments typically above 800 °C. The extension of the approach to a wider range of ceramic compositions and applications, both structural and thermo-structural (refractory components, thermal barrier coatings) or functional (bioactive ceramics, luminescent materials), mainly relies on modifications of the polymers at the nano-scale, i.e., on the introduction of nano-sized fillers and/or chemical additives, leading to nano-structured ceramic components upon thermal conversion. Fillers and additives may react with the main ceramic residue of the polymer, leading to ceramics of significant engineering interest (such as silicates and SiAlONs), or cause the formation of secondary phases, significantly affecting the functionalities of the polymer-derived matrix. PMID:28788548

Duck hepatitis B virus covalently closed circular DNA appears to survive hepatocyte mitosis in the growing liver

International Nuclear Information System (INIS)

Reaiche-Miller, Georget Y.; Thorpe, Michael; Low, Huey Chi; Qiao, Qiao; Scougall, Catherine A.; Mason, William S.; Litwin, Samuel; Jilbert, Allison R.

2013-01-01

Nucleos(t)ide analogues that inhibit hepatitis B virus (HBV) DNA replication are typically used as monotherapy for chronically infected patients. Treatment with a nucleos(t)ide analogue eliminates most HBV DNA replication intermediates and produces a gradual decline in levels of covalently closed circular DNA (cccDNA), the template for viral RNA synthesis. It remains uncertain if levels of cccDNA decline primarily through hepatocyte death, or if loss also occurs during hepatocyte mitosis. To determine if cccDNA survives mitosis, growing ducklings infected with duck hepatitis B virus (DHBV) were treated with the nucleoside analogue, Entecavir. Viremia was suppressed at least 10 5 -fold, during a period when average liver mass increased 23-fold. Analysis of the data suggested that if cccDNA synthesis was completely inhibited, at least 49% of cccDNA survived hepatocyte mitosis. However, there was a large duck-to-duck variation in cccDNA levels, suggesting that low level cccDNA synthesis may contribute to this apparent survival through mitosis. - Highlights: • The hepatitis B virus nuclear template is covalently closed circular DNA (cccDNA). • cccDNA was studied during liver growth in duck hepatitis B virus infected ducks. • Virus DNA replication and new cccDNA synthesis were inhibited with Entecavir. • At least 49% of cccDNA appeared to survive hepatocyte mitosis. • Low level virus DNA synthesis may contribute to survival of cccDNA through mitosis

Duck hepatitis B virus covalently closed circular DNA appears to survive hepatocyte mitosis in the growing liver

Energy Technology Data Exchange (ETDEWEB)

Reaiche-Miller, Georget Y.; Thorpe, Michael; Low, Huey Chi; Qiao, Qiao; Scougall, Catherine A. [School of Molecular and Biomedical Science, University of Adelaide, Adelaide, SA 5005 (Australia); Mason, William S.; Litwin, Samuel [Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, PA 19111 (United States); Jilbert, Allison R., E-mail: allison.jilbert@adelaide.edu.au [School of Molecular and Biomedical Science, University of Adelaide, Adelaide, SA 5005 (Australia)

2013-11-15

Nucleos(t)ide analogues that inhibit hepatitis B virus (HBV) DNA replication are typically used as monotherapy for chronically infected patients. Treatment with a nucleos(t)ide analogue eliminates most HBV DNA replication intermediates and produces a gradual decline in levels of covalently closed circular DNA (cccDNA), the template for viral RNA synthesis. It remains uncertain if levels of cccDNA decline primarily through hepatocyte death, or if loss also occurs during hepatocyte mitosis. To determine if cccDNA survives mitosis, growing ducklings infected with duck hepatitis B virus (DHBV) were treated with the nucleoside analogue, Entecavir. Viremia was suppressed at least 10{sup 5}-fold, during a period when average liver mass increased 23-fold. Analysis of the data suggested that if cccDNA synthesis was completely inhibited, at least 49% of cccDNA survived hepatocyte mitosis. However, there was a large duck-to-duck variation in cccDNA levels, suggesting that low level cccDNA synthesis may contribute to this apparent survival through mitosis. - Highlights: • The hepatitis B virus nuclear template is covalently closed circular DNA (cccDNA). • cccDNA was studied during liver growth in duck hepatitis B virus infected ducks. • Virus DNA replication and new cccDNA synthesis were inhibited with Entecavir. • At least 49% of cccDNA appeared to survive hepatocyte mitosis. • Low level virus DNA synthesis may contribute to survival of cccDNA through mitosis.

Characterization and bioactivity of nano-submicro octacalcium phosphate/gelatin composite

International Nuclear Information System (INIS)

Miura, Kei-ichiro; Anada, Takahisa; Honda, Yoshitomo; Shiwaku, Yukari; Kawai, Tadashi; Echigo, Seishi; Takahashi, Tetsu; Suzuki, Osamu

2013-01-01

The present study was designed to investigate the physicochemical and bioactive properties of a nano-submicro sized octacalcium phosphate (OCP)-dispersed gelatin (Gel) composite (nano-submicro OCP/Gel) used as a bone substitute material in various bone defects. Well-grown, synthesized OCP was mechanically ground from 100 to 300 μm-sieved granules to particles that were approximately 500 nm in size. Then, 50 wt% of the nano-submicro OCP was mixed with porcine skin-derived acid extracted gelatin. The mixture was molded and lyophilized and then subjected to dehydrothermal crosslinking. X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy showed that the structure of OCP was retained even after mechanical grinding to a nano-submicro scale level as well as inclusion in the Gel matrix. The bioactivity of nano-submicro OCP/Gel was examined by immersing the composite in simulated body fluid (SBF) for 7 days and by implanting it in rat critical-sized calvaria defects for 8 weeks. The nano-submicro OCP tended to convert to low crystalline hydroxyapatite (HA) in SBF as assessed by XRD. The nano-submicro OCP/Gel exhibited osteoconductivity in vivo, yielding new bone formation that was closely associated with the implanted composite. These results suggest that the nano-submicro OCP/Gel composite exhibits similar osteoconductivity as observed in other OCP-based materials previously reported and could be used as a bone substitute material for repairing various defects in bone.

Characterization and bioactivity of nano-submicro octacalcium phosphate/gelatin composite

Energy Technology Data Exchange (ETDEWEB)

Miura, Kei-ichiro [Division of Craniofacial Function Engineering, Tohoku University Graduate School of Dentistry, Sendai (Japan); Division of Oral and Maxillofacial Surgery, Tohoku University Graduate School of Dentistry, Sendai (Japan); Anada, Takahisa; Honda, Yoshitomo [Division of Craniofacial Function Engineering, Tohoku University Graduate School of Dentistry, Sendai (Japan); Shiwaku, Yukari [Division of Craniofacial Function Engineering, Tohoku University Graduate School of Dentistry, Sendai (Japan); Division of Advanced Prosthetic Dentistry, Tohoku University Graduate School of Dentistry, Sendai (Japan); Kawai, Tadashi; Echigo, Seishi; Takahashi, Tetsu [Division of Oral and Maxillofacial Surgery, Tohoku University Graduate School of Dentistry, Sendai (Japan); Suzuki, Osamu, E-mail: suzuki-o@m.tohoku.ac.jp [Division of Craniofacial Function Engineering, Tohoku University Graduate School of Dentistry, Sendai (Japan)

2013-10-01

The present study was designed to investigate the physicochemical and bioactive properties of a nano-submicro sized octacalcium phosphate (OCP)-dispersed gelatin (Gel) composite (nano-submicro OCP/Gel) used as a bone substitute material in various bone defects. Well-grown, synthesized OCP was mechanically ground from 100 to 300 μm-sieved granules to particles that were approximately 500 nm in size. Then, 50 wt% of the nano-submicro OCP was mixed with porcine skin-derived acid extracted gelatin. The mixture was molded and lyophilized and then subjected to dehydrothermal crosslinking. X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy showed that the structure of OCP was retained even after mechanical grinding to a nano-submicro scale level as well as inclusion in the Gel matrix. The bioactivity of nano-submicro OCP/Gel was examined by immersing the composite in simulated body fluid (SBF) for 7 days and by implanting it in rat critical-sized calvaria defects for 8 weeks. The nano-submicro OCP tended to convert to low crystalline hydroxyapatite (HA) in SBF as assessed by XRD. The nano-submicro OCP/Gel exhibited osteoconductivity in vivo, yielding new bone formation that was closely associated with the implanted composite. These results suggest that the nano-submicro OCP/Gel composite exhibits similar osteoconductivity as observed in other OCP-based materials previously reported and could be used as a bone substitute material for repairing various defects in bone.

Optimizing Cr(VI) and Tc(VII) remediation through nano-scale biomineral engineering

International Nuclear Information System (INIS)

Cutting, R.S.; Coker, V.S.; Telling, N.D.; Kimber, R.L.; Pearce, C.I.; Ellis, B.; Lawson, R; van der Laan, G.; Pattrick, R.A.D.; Vaughan, D.J.; Arenholz, E.; Lloyd, J.R.

2009-01-01

To optimize the production of biomagnetite for the bioremediation of metal oxyanion contaminated waters, the reduction of aqueous Cr(VI) to Cr(III) by two biogenic magnetites and a synthetic magnetite was evaluated under batch and continuous flow conditions. Results indicate that nano-scale biogenic magnetite produced by incubating synthetic schwertmannite powder in cell suspensions of Geobacter sulfurreducens is more efficient at reducing Cr(VI) than either biogenic nano-magnetite produced from a suspension of ferrihydrite 'gel' or synthetic nano-scale Fe 3 O 4 powder. Although X-ray Photoelectron Spectroscopy (XPS) measurements obtained from post-exposure magnetite samples reveal that both Cr(III) and Cr(VI) are associated with nanoparticle surfaces, X-ray Magnetic Circular Dichroism (XMCD) studies indicate that some Cr(III) has replaced octahedrally coordinated Fe in the lattice of the magnetite. Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES) measurements of total aqueous Cr in the associated solution phase indicated that, although the majority of Cr(III) was incorporated within or adsorbed to the magnetite samples, a proportion (∼10-15 %) was released back into solution. Studies of Tc(VII) uptake by magnetites produced via the different synthesis routes also revealed significant differences between them as regards effectiveness for remediation. In addition, column studies using a γ-camera to obtain real time images of a 99m Tc(VII) radiotracer were performed to visualize directly the relative performances of the magnetite sorbents against ultra-trace concentrations of metal oxyanion contaminants. Again, the magnetite produced from schwertmannite proved capable of retaining more (∼20%) 99m Tc(VII) than the magnetite produced from ferrihydrite, confirming that biomagnetite production for efficient environmental remediation can be fine-tuned through careful selection of the initial Fe(III) mineral substrate supplied to Fe

Optimizing Cr(VI) and Tc(VII) remediation through nano-scale biomineral engineering

Energy Technology Data Exchange (ETDEWEB)

Cutting, R. S.; Coker, V. S.; Telling, N. D.; Kimber, R. L.; Pearce, C. I.; Ellis, B.; Lawson, R; van der Laan, G.; Pattrick, R.A.D.; Vaughan, D.J.; Arenholz, E.; Lloyd, J. R.

2009-09-09

To optimize the production of biomagnetite for the bioremediation of metal oxyanion contaminated waters, the reduction of aqueous Cr(VI) to Cr(III) by two biogenic magnetites and a synthetic magnetite was evaluated under batch and continuous flow conditions. Results indicate that nano-scale biogenic magnetite produced by incubating synthetic schwertmannite powder in cell suspensions of Geobacter sulfurreducens is more efficient at reducing Cr(VI) than either biogenic nano-magnetite produced from a suspension of ferrihydrite 'gel' or synthetic nano-scale Fe{sub 3}O{sub 4} powder. Although X-ray Photoelectron Spectroscopy (XPS) measurements obtained from post-exposure magnetite samples reveal that both Cr(III) and Cr(VI) are associated with nanoparticle surfaces, X-ray Magnetic Circular Dichroism (XMCD) studies indicate that some Cr(III) has replaced octahedrally coordinated Fe in the lattice of the magnetite. Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES) measurements of total aqueous Cr in the associated solution phase indicated that, although the majority of Cr(III) was incorporated within or adsorbed to the magnetite samples, a proportion ({approx}10-15 %) was released back into solution. Studies of Tc(VII) uptake by magnetites produced via the different synthesis routes also revealed significant differences between them as regards effectiveness for remediation. In addition, column studies using a {gamma}-camera to obtain real time images of a {sup 99m}Tc(VII) radiotracer were performed to visualize directly the relative performances of the magnetite sorbents against ultra-trace concentrations of metal oxyanion contaminants. Again, the magnetite produced from schwertmannite proved capable of retaining more ({approx}20%) {sup 99m}Tc(VII) than the magnetite produced from ferrihydrite, confirming that biomagnetite production for efficient environmental remediation can be fine-tuned through careful selection of the initial Fe(III) mineral

Molecular Precision at Micrometer Length Scales: Hierarchical Assembly of DNA-Protein Nanostructures.

Science.gov (United States)

Schiffels, Daniel; Szalai, Veronika A; Liddle, J Alexander

2017-07-25

Robust self-assembly across length scales is a ubiquitous feature of biological systems but remains challenging for synthetic structures. Taking a cue from biology-where disparate molecules work together to produce large, functional assemblies-we demonstrate how to engineer microscale structures with nanoscale features: Our self-assembly approach begins by using DNA polymerase to controllably create double-stranded DNA (dsDNA) sections on a single-stranded template. The single-stranded DNA (ssDNA) sections are then folded into a mechanically flexible skeleton by the origami method. This process simultaneously shapes the structure at the nanoscale and directs the large-scale geometry. The DNA skeleton guides the assembly of RecA protein filaments, which provides rigidity at the micrometer scale. We use our modular design strategy to assemble tetrahedral, rectangular, and linear shapes of defined dimensions. This method enables the robust construction of complex assemblies, greatly extending the range of DNA-based self-assembly methods.

A large-scale association study for nanoparticle C60 uncovers mechanisms of nanotoxicity disrupting the native conformations of DNA/RNA.

Science.gov (United States)

Xu, Xue; Wang, Xia; Li, Yan; Wang, Yonghua; Yang, Ling

2012-09-01

Nano-scale particles have attracted a lot of attention for its potential use in medical studies, in particular for the diagnostic and therapeutic purposes. However, the toxicity and other side effects caused by the undesired interaction between nanoparticles and DNA/RNA are not clear. To address this problem, a model to evaluate the general rules governing how nanoparticles interact with DNA/RNA is demanded. Here by, use of an examination of 2254 native nucleotides with molecular dynamics simulation and thermodynamic analysis, we demonstrate how the DNA/RNA native structures are disrupted by the fullerene (C60) in a physiological condition. The nanoparticle was found to bind with the minor grooves of double-stranded DNA and trigger unwinding and disrupting of the DNA helix, which indicates C60 can potentially inhibit the DNA replication and induce potential side effects. In contrast to that of DNA, C60 only binds to the major grooves of RNA helix, which stabilizes the RNA structure or transforms the configuration from stretch to curl. This finding sheds new light on how C60 inhibits reverse transcription as HIV replicates. In addition, the binding of C60 stabilizes the structures of RNA riboswitch, indicating that C60 might regulate the gene expression. The binding energies of C60 with different genomic fragments varies in the range of -56 to -10 kcal mol(-1), which further verifies the role of nanoparticle in DNA/RNA damage. Our findings reveal a general mode by which C60 causes DNA/RNA damage or other toxic effects at a systematic level, suggesting it should be cautious to handle these nanomaterials in various medical applications.

Micro- and nano-scale characterization to study the thermal degradation of cement-based materials

International Nuclear Information System (INIS)

Lim, Seungmin; Mondal, Paramita

2014-01-01

The degradation of hydration products of cement is known to cause changes in the micro- and nano-structure, which ultimately drive thermo-mechanical degradation of cement-based composite materials at elevated temperatures. However, a detailed characterization of these changes is still incomplete. This paper presents results of an extensive experimental study carried out to investigate micro- and nano-structural changes that occur due to exposure of cement paste to high temperatures. Following heat treatment of cement paste up to 1000 °C, damage states were studied by compressive strength test, thermogravimetric analysis (TGA), scanning electron microscopy (SEM) atomic force microscopy (AFM) and AFM image analysis. Using experimental results and research from existing literature, new degradation processes that drive the loss of mechanical properties of cement paste are proposed. The development of micro-cracks at the interface between unhydrated cement particles and paste matrix, a change in C–S–H nano-structure and shrinkage of C–S–H, are considered as important factors that cause the thermal degradation of cement paste. - Highlights: • The thermal degradation of hydration products of cement is characterized at micro- and nano-scale using scanning electron microscopy (SEM) and atomic force microscopy (AFM). • The interface between unhydrated cement particles and the paste matrix is considered the origin of micro-cracks. • When cement paste is exposed to temperatures above 300 ºC, the nano-structure of C-S-H becomes a more loosely packed globular structure, which could be indicative of C-S-H shrinkage

Sub-10-nm suspended nano-web formation by direct laser writing

Science.gov (United States)

Wang, Sihao; Yu, Ye; Liu, Hailong; Lim, Kevin T. P.; Madurai Srinivasan, Bharathi; Zhang, Yong Wei; Yang, Joel K. W.

2018-06-01

A diffraction-limited three-dimensional (3D) direct laser writing (DLW) system based on two-photon polymerization can routinely pattern structures at the 100 nm length scale. Several schemes have been developed to improve the patterning resolution of 3D DLW but often require customized resist formulations or multi-wavelength exposures. Here, we introduce a scheme to produce suspended nano-webs with feature sizes below 10 nm in IP-Dip resist using sub-threshold exposure conditions in a commercial DLW system. The narrowest suspended lines (nano-webs) measured 7 nm in width. Larger ∼20 nm nano-webs were patterned with ∼80% yield at increased laser powers. In addition, closely spaced nano-gaps with a center-to-center distance of 33 nm were produced by patterning vertically displaced suspended lines followed by metal deposition and liftoff. We provide hypotheses and present preliminary results for a mechanism involving the initiation of a percolative path and a strain-induced narrowing in the nano-web formation. Our approach allows selective features to be patterned with dimensions comparable to the sub-10 nm patterning capability of electron-beam lithography (EBL).

Quasi-particle spectrum of nano-scale conventional and unconventional superconductors under magnetic field

International Nuclear Information System (INIS)

Kato, Masaru; Suematsu, Hisataka; Machida, Masahiko; Koyama, Tomio; Ishida, Takekazu

2005-01-01

We have developed a numerical method to solve the Bogoliubov-de Gennes equation for nano-scaled isotropic and d-wave superconductors. It is based on the finite element method, and therefore applicable to arbitrary geometries. We argue the difference of the local density of states between isotropic and a d-wave superconducting square plate. For d-wave case, it appears as intrinsic surface bound states

[Preparation of nano-nacre artificial bone].

Science.gov (United States)

Chen, Jian-ting; Tang, Yong-zhi; Zhang, Jian-gang; Wang, Jian-jun; Xiao, Ying

2008-12-01

To assess the improvements in the properties of nano-nacre artificial bone prepared on the basis of nacre/polylactide acid composite artificial bone and its potential for clinical use. The compound of nano-scale nacre powder and poly-D, L-lactide acid (PDLLA) was used to prepare the cylindrical hollow artificial bone, whose properties including raw material powder scale, pore size, porosity and biomechanical characteristics were compared with another artificial bone made of micron-scale nacre powder and PDLLA. Scanning electron microscope showed that the average particle size of the nano-nacre powder was 50.4-/+12.4 nm, and the average pore size of the artificial bone prepared using nano-nacre powder was 215.7-/+77.5 microm, as compared with the particle size of the micron-scale nacre powder of 5.0-/+3.0 microm and the pore size of the resultant artificial bone of 205.1-/+72.0 microm. The porosities of nano-nacre artificial bone and the micron-nacre artificial bone were (65.4-/+2.9)% and (53.4-/+2.2)%, respectively, and the two artificial bones had comparable compressive strength and Young's modulus, but the flexural strength of the nano-nacre artificial bone was lower than that of the micro-nacre artificial bone. The nano-nacre artificial bone allows better biodegradability and possesses appropriate pore size, porosity and biomechanical properties for use as a promising material in bone tissue engineering.

DNA damage in healthy individuals and respiratory patients after treating whole blood in vitro with the bulk and nano forms of NSAIDs

Directory of Open Access Journals (Sweden)

Diana Anderson

2016-09-01

Full Text Available Non-steroidal anti-inflammatory drugs (NSAIDs inhibit COX enzyme activity which affects the inflammatory response. Inflammation is associated with increasing cancer incidence. Pre-clinical and clinical studies have shown that NSAID treatment could cause an anti-tumour effect in cancers. In the present study, blood was taken from healthy individuals (n=17 and patients with respiratory diseases or lung cancer (n=36. White blood cells (WBC were treated with either a micro-suspension, i.e. bulk (B or nano-suspension (N of aspirin (ASP or ibuprofen (IBU up to 500 µg/ml in the comet assay and up to 125 µg/ml in the micronucleus assay. In this study results were compared against untreated lymphocytes and their corresponding treated groups. The results showed, thgat NSAIDs in their nano form significantly reduced the DNA damage in WBCs from lung cancer patients in bulk and nano compared to untreated lymphocytes. Also, there was a decrease in the level of DNA damage in the comet assay after treating WBCs from healthy individuals, asthma and COPD groups with aspirin N (ASP N but not with IBU N. In addition, the number of micronuclei decreased after treatment with NSAIDs in their nano form (ASP N and IBU N in the healthy as well as in the lung cancer group. However, this was not the case for micronucleus frequency in asthma and COPD patients. These data show that lymphocytes from different groups respond differently to treatment with ASP and IBU as measured by comet assay and micronucleus assay, and that the size of the suspended particles of the drugs affects responses.

Formation of Nano scale Bio imprints of Muscle Cells Using UV-Cured Spin-Coated Polymers

International Nuclear Information System (INIS)

Samsuri, F.; Alkaisi, M.M.; Mitchell, J.S.; Evans, J.J.

2009-01-01

We report a nano scale replication method suitable for biological specimens that has potential in single cell studies and in formation of 3D biocompatible scaffolds. Earlier studies using a heat-curable polydimethylsiloxane (PDMS) or a UV-curable elastomer introduced Bio imprint replication to facilitate cell imaging. However, the replicating conditions for thermal polymerization are known to cause cell dehydration during curing. In this study, a UV-cured methacrylate copolymer was developed for use in creating replicas of living cells and was tested on rat muscle cells. Bio imprints of muscle cells were formed by spin coating under UV irradiation. The polymer replicas were then separated from the muscle cells and were analyzed under an Atomic Force Microscope (AFM), in tapping mode, because it has low tip-sample forces and thus will not destroy the fine structures of the imprint. The new polymer is biocompatible with higher replication resolution and has a faster curing process than other types of silicon-based organic polymers such as PDMS. High resolution images of the muscle cell imprints showed the micro-and nano structures of the muscle cells, including cellular fibers and structures within the cell membranes. The AFM is able to image features at nano scale resolution with the potential for recognizing abnormalities on cell membranes at early stages of disease progression.

A new multiscale model to describe a modified Hall-Petch relation at different scales for nano and micro materials

Science.gov (United States)

Fadhil, Sadeem Abbas; Alrawi, Aoday Hashim; Azeez, Jazeel H.; Hassan, Mohsen A.

2018-04-01

In the present work, a multiscale model is presented and used to modify the Hall-Petch relation for different scales from nano to micro. The modified Hall-Petch relation is derived from a multiscale equation that determines the cohesive energy between the atoms and their neighboring grains. This brings with it a new term that was originally ignored even in the atomistic models. The new term makes it easy to combine all other effects to derive one modified equation for the Hall-Petch relation that works for all scales together, without the need to divide the scales into two scales, each scale with a different equation, as it is usually done in other works. Due to that, applying the new relation does not require a previous knowledge of the grain size distribution. This makes the new derived relation more consistent and easier to be applied for all scales. The new relation is used to fit the data for Copper and Nickel and it is applied well for the whole range of grain sizes from nano to micro scales.

Material versatility using replica molding for large-scale fabrication of high aspect-ratio, high density arrays of nano-pillars

International Nuclear Information System (INIS)

Li, Y; Menon, C; Ng, H W; Gates, B D

2014-01-01

Arrays of high aspect-ratio (AR) nano-pillars have attracted a lot of interest for various applications, such as for use in solar cells, surface acoustic sensors, tissue engineering, bio-inspired adhesives and anti-reflective surfaces. Each application may require a different structural material, which can vary in the required chemical composition and mechanical properties. In this paper, a low cost fabrication procedure is proposed for large scale, high AR and high density arrays of nano-pillars. The proposed method enables the replication of a master with high fidelity, using the subsequent replica molds multiple times, and preparing arrays of nano-pillars in a variety of different materials. As an example applied to bio-inspired dry adhesion, polymeric arrays of nano-pillars are prepared in this work. Thermoset and thermoplastic nano-pillar arrays are examined using an atomic force microscope to assess their adhesion strength and its uniformity. Results indicate the proposed method is robust and can be used to reliably prepare nano-structures with a high AR. (paper)

Free-standing nano-scale graphite saturable absorber for passively mode-locked erbium doped fiber ring laser

International Nuclear Information System (INIS)

Lin, Y-H; Lin, G-R

2012-01-01

The free-standing graphite nano-particle located between two FC/APC fiber connectors is employed as the saturable absorber to passively mode-lock the ring-type Erbium-doped fiber laser (EDFL). The host-solvent-free graphite nano-particles with sizes of 300 – 500 nm induce a comparable modulation depth of 54%. The interlayer-spacing and lattice fluctuations of polished graphite nano-particles are observed from the weak 2D band of Raman spectrum and the azimuth angle shift of –0.32 ° of {002}-orientation dependent X-ray diffraction peak. The graphite nano-particles mode-locked EDFL generates a 1.67-ps pulsewidth at linearly dispersion-compensated regime with a repetition rate of 9.1 MHz. The time-bandwidth product of 0.325 obtained under a total intra-cavity group-delay-dispersion of –0.017 ps 2 is nearly transform-limited. The extremely high stability of the nano-scale graphite saturable absorber during mode-locking is observed at an intra-cavity optical energy density of 7.54 mJ/cm 2 . This can be attributed to its relatively high damage threshold (one order of magnitude higher than the graphene) on handling the optical energy density inside the EDFL cavity. The graphite nano-particle with reduced size and sufficient coverage ratio can compete with other fast saturable absorbers such as carbon nanotube or graphene to passively mode-lock fiber lasers with decreased insertion loss and lasing threshold

Field limit and nano-scale surface topography of superconducting radio-frequency cavity made of extreme type II superconductor

OpenAIRE

Kubo, Takayuki

2014-01-01

The field limit of superconducting radio-frequency cavity made of type II superconductor with a large Ginzburg-Landau parameter is studied with taking effects of nano-scale surface topography into account. If the surface is ideally flat, the field limit is imposed by the superheating field. On the surface of cavity, however, nano-defects almost continuously distribute and suppress the superheating field everywhere. The field limit is imposed by an effective superheating field given by the pro...

Performance assessment and optimization of an irreversible nano-scale Stirling engine cycle operating with Maxwell-Boltzmann gas

Science.gov (United States)

Ahmadi, Mohammad H.; Ahmadi, Mohammad-Ali; Pourfayaz, Fathollah

2015-09-01

Developing new technologies like nano-technology improves the performance of the energy industries. Consequently, emerging new groups of thermal cycles in nano-scale can revolutionize the energy systems' future. This paper presents a thermo-dynamical study of a nano-scale irreversible Stirling engine cycle with the aim of optimizing the performance of the Stirling engine cycle. In the Stirling engine cycle the working fluid is an Ideal Maxwell-Boltzmann gas. Moreover, two different strategies are proposed for a multi-objective optimization issue, and the outcomes of each strategy are evaluated separately. The first strategy is proposed to maximize the ecological coefficient of performance (ECOP), the dimensionless ecological function (ecf) and the dimensionless thermo-economic objective function ( F . Furthermore, the second strategy is suggested to maximize the thermal efficiency ( η), the dimensionless ecological function (ecf) and the dimensionless thermo-economic objective function ( F). All the strategies in the present work are executed via a multi-objective evolutionary algorithms based on NSGA∥ method. Finally, to achieve the final answer in each strategy, three well-known decision makers are executed. Lastly, deviations of the outcomes gained in each strategy and each decision maker are evaluated separately.

Nano Scale Mechanical Analysis of Biomaterials Using Atomic Force Microscopy

Science.gov (United States)

Dutta, Diganta

The atomic force microscope (AFM) is a probe-based microscope that uses nanoscale and structural imaging where high resolution is desired. AFM has also been used in mechanical, electrical, and thermal engineering applications. This unique technique provides vital local material properties like the modulus of elasticity, hardness, surface potential, Hamaker constant, and the surface charge density from force versus displacement curve. Therefore, AFM was used to measure both the diameter and mechanical properties of the collagen nanostraws in human costal cartilage. Human costal cartilage forms a bridge between the sternum and bony ribs. The chest wall of some humans is deformed due to defective costal cartilage. However, costal cartilage is less studied compared to load bearing cartilage. Results show that there is a difference between chemical fixation and non-chemical fixation treatments. Our findings imply that the patients' chest wall is mechanically weak and protein deposition is abnormal. This may impact the nanostraws' ability to facilitate fluid flow between the ribs and the sternum. At present, AFM is the only tool for imaging cells' ultra-structure at the nanometer scale because cells are not homogeneous. The first layer of the cell is called the cell membrane, and the layer under it is made of the cytoskeleton. Cancerous cells are different from normal cells in term of cell growth, mechanical properties, and ultra-structure. Here, force is measured with very high sensitivity and this is accomplished with highly sensitive probes such as a nano-probe. We performed experiments to determine ultra-structural differences that emerge when such cancerous cells are subject to treatments such as with drugs and electric pulses. Jurkat cells are cancerous cells. These cells were pulsed at different conditions. Pulsed and non-pulsed Jurkat cell ultra-structures were investigated at the nano meter scale using AFM. Jurkat cell mechanical properties were measured under

The effect of micro nano multi-scale structures on the surface wettability

International Nuclear Information System (INIS)

Lee, Sang Min; Jung, Im Deok; Ko, Jong Soo

2008-01-01

Surface wettability in terms of the size of the micro nano structures has been examined. To evaluate the influence of the nano structures on the contact angles, we fabricated two different kinds of structures: square-pillar-type microstructure with nano-protrusions and without nano-protrusions. Microstructure and nanostructure arrays were fabricated by Deep Reactive Ion Etching (DRIE) and Reactive Ion Etching (RIE) processes, respectively. And Plasma Polymerized FluoroCarbon (PPFC) was finally deposited onto the fabricated structures. Average value of the measured contact angles from microstructures with nano-protrusions was 6.37 .deg. higher than that from microstructures without nano-protrusions. This result indicates that the nano-protrusions give a crucial effect to increase the contact angle

Selective and lithography-independent fabrication of 20 nm nano-gap electrodes and nano-channels for nanoelectrofluidics applications

International Nuclear Information System (INIS)

Zhang, J Y; Wang, X F; Wang, X D; Fan, Z C; Li, Y; Ji, An; Yang, F H

2010-01-01

A new method has been developed to selectively fabricate nano-gap electrodes and nano-channels by conventional lithography. Based on a sacrificial spacer process, we have successfully obtained sub-100-nm nano-gap electrodes and nano-channels and further reduced the dimensions to 20 nm by shrinking the sacrificial spacer size. Our method shows good selectivity between nano-gap electrodes and nano-channels due to different sacrificial spacer etch conditions. There is no length limit for the nano-gap electrode and the nano-channel. The method reported in this paper also allows for wafer scale fabrication, high throughput, low cost, and good compatibility with modern semiconductor technology.

Multi-objective optimization and exergetic-sustainability of an irreversible nano scale Braysson cycle operating with Ma

Directory of Open Access Journals (Sweden)

Mohammad H. Ahmadi

2016-06-01

Full Text Available Nano technology is developed in this decade and changes the way of life. Moreover, developing nano technology has effect on the performance of the materials and consequently improves the efficiency and robustness of them. So, nano scale thermal cycles will be probably engaged in the near future. In this paper, a nano scale irreversible Braysson cycle is studied thermodynamically for optimizing the performance of the Braysson cycle. In the aforementioned cycle an ideal Maxwell–Boltzmann gas is used as a working fluid. Furthermore, three different plans are used for optimizing with multi-objectives; though, the outputs of the abovementioned plans are assessed autonomously. Throughout the first plan, with the purpose of maximizing the ecological coefficient of performance and energy efficiency of the system, multi-objective optimization algorithms are used. Furthermore, in the second plan, two objective functions containing the ecological coefficient of performance and the dimensionless Maximum available work are maximized synchronously by utilizing multi-objective optimization approach. Finally, throughout the third plan, three objective functions involving the dimensionless Maximum available work, the ecological coefficient of performance and energy efficiency of the system are maximized synchronously by utilizing multi-objective optimization approach. The multi-objective evolutionary approach based on the non-dominated sorting genetic algorithm approach is used in this research. Making a decision is performed by three different decision makers comprising linear programming approaches for multidimensional analysis of preference and an approach for order of preference by comparison with ideal answer and Bellman–Zadeh. Lastly, analysis of error is employed to determine deviation of the outcomes gained from each plan.

Droplets and the three-phase contact line at the nano-scale. Statics and dynamics

Science.gov (United States)

Yatsyshin, Petr; Sibley, David; Savva, Nikos; Kalliadasis, Serafim

2014-11-01

Understanding the behaviour of the solid-liquid-vapour contact line at the scale of several tens of molecular diameters is important in wetting hydrodynamics with applications in micro- and nano-fluidics, including the design of lab-on-a-chip devices and surfaces with specific wetting properties. Due to the fluid inhomogeneity at the nano-scale, the application of continuum-mechanical approaches is limited, and a natural way to remedy this is to seek descriptions accounting for the non-local molecular-level interactions. Density Functional Theory (DFT) for fluids offers a statistical-mechanical framework based on expressing the free energy of the fluid-solid pair as a functional of the spatially varying fluid density. DFT allows us to investigate small drops deposited on planar substrates whilst keeping track of the microscopic structural details of the fluid. Starting from a model of intermolecular forces, we systematically obtain interfaces, surface tensions, and the microscopic contact angle. Using a dynamic extension of equilibrium DFT, we investigate the diffusion-driven evolution of the three-phase contact line to gain insight into the dynamic behaviour of the microscopic contact angle, which is still under debate.

Gallium Nitride: A Nano scale Study using Electron Microscopy and Associated Techniques

International Nuclear Information System (INIS)

Mohammed Benaissa; Vennegues, Philippe

2008-01-01

A complete nano scale study on GaN thin films doped with Mg. This study was carried out using TEM and associated techniques such as HREM, CBED, EDX and EELS. It was found that the presence of triangular defects (of few nanometers in size) within GaN:Mg films were at the origin of unexpected electrical and optical behaviors, such as a decrease in the free hole density at high Mg doping. It is shown that these defects are inversion domains limited with inversion-domains boundaries. (author)

In Vitro Phototoxicity and Hazard Identification of Nano-scale Titanium Dioxide

Science.gov (United States)

Nano-titanium dioxide (nano-Ti02) catalyzes many reactions under UV radiation and is hypothesized to cause phototoxicity. A human-derived line of retinal pigment epithelial cells (ARPE-19) was treated with six different samples of nano-Ti02 and exposed to UVA radiation. The Ti02 ...

Nano-scale patterns of polymers and their structural phase transitions

Energy Technology Data Exchange (ETDEWEB)

Matsushita, Yushu [Tokyo Univ. (Japan). Inst. for Solid State Physics

1998-03-01

Nano-scale patterns formed by polymers and their related soft materials were investigated by measuring neutron scattering from them. Two apparatuses installed at cold neutron guides in JRR-3M, a small angle neutron scattering (SANS) apparatus and a neutron reflectometer, which give out elastic scattering intensities, were used. Chain dimensions of polystyrenes diluted with low molecular weight homologous polystyrenes, orientation behaviour of microphase-separated block copolymer in concentrated solutions under shear, shrinkage and recovery of polyvinylalcohol gel with temperature and structural phase transition of microemulsion under high-pressure and so on were measured by SANS, while microphase-separated polystyrene(S)/poly(2-vinylpyridine)(P) interfaces of a PSP triblock copolymer was observed by specular neutron reflectivity measurements. (author)

Fabrication of nano-electrode arrays of free-standing carbon nanotubes on nano-patterned substrate by imprint method

Energy Technology Data Exchange (ETDEWEB)

Chang, W.S., E-mail: paul@kimm.re.kr [Department of Nano Mechanics, Korea Institute of Machinery and Materials, 104 Sinseongno, Yuseong-gu Daejeon 305-343 (Korea, Republic of); Kim, J.W. [Gyeongbuk Hybrid Technology Institute, 36 Goeyeon-dong, Yeongcheon, Gyeongbuk 770-170 (Korea, Republic of); Choi, D.G. [Department of Nano Mechanics, Korea Institute of Machinery and Materials, 104 Sinseongno, Yuseong-gu Daejeon 305-343 (Korea, Republic of); Han, C.S. [Gyeongbuk Hybrid Technology Institute, 36 Goeyeon-dong, Yeongcheon, Gyeongbuk 770-170 (Korea, Republic of)

2011-01-15

The synthesis of isolated carbon nanotubes with uniform outer diameters and ordered spacing over wafer-scale areas was investigated for fabrication of nano-electrode arrays on silicon wafers for field emission and sensor devices. Multi-walled carbon nanotubes (MWCNTs) were grown on TiN electrode layer with iron catalyst patterned by nano-imprint lithography (NIL), which allows the precise placement of individual CNTs on a substrate. The proposed techniques, including plasma-enhanced chemical vapor deposition (PECVD) and NIL, are simple, inexpensive, and reproducible methods for fabrication of nano-scale devices in large areas. The catalyst patterns were defined by an array of circles with 200 nm in diameter, and variable lengths of pitch. The nano-patterned master and Fe catalyst were observed with good pattern fidelity over a large area by atomic force microscope (AFM) and scanning electron microscopy (SEM). Nano-electrodes of MWCNTs had diameters ranging from 50 nm to 100 nm and lengths of about 300 nm. Field emission tests showed the reducing ignition voltage as the geometry of nanotube arrays was controlled by catalyst patterning. These results showed a wafer-scale approach to the control of the size, pitch, and position of nano-electrodes of nanotubes for various applications including electron field-emission sources, electrochemical probes, functionalized sensor elements, and so on.

Transferring metallic nano-island on hydrogen passivated silicon surface for nano-electronics

International Nuclear Information System (INIS)

Deng, J; Troadec, C; Joachim, C

2009-01-01

In a planar configuration, precise positioning of ultra-flat metallic nano-islands on semiconductor surface opens a way to construct nanostructures for atomic scale interconnects. Regular triangular Au nano-islands have been grown on atomically flat MoS 2 substrates and manipulated by STM to form nanometer gap metal-pads connector for single molecule electronics study. The direct assembly of regular shaped metal nano-islands on H-Si(100) is not achievable. Here we present how to transfer Au triangle nano-islands from MoS 2 onto H-Si(100) in a clean manner. In this experiment, clean MoS 2 substrates are patterned as array of MoS 2 pillars with height of 8 μm. The Au triangle nano-islands are grown on top of the pillars. Successful printing transfer of these Au nano-islands from the MoS 2 pillars to the H-Si(100) is demonstrated.

DNA Polymerase κ Is a Key Cellular Factor for the Formation of Covalently Closed Circular DNA of Hepatitis B Virus.

Directory of Open Access Journals (Sweden)

Yonghe Qi

2016-10-01

Full Text Available Hepatitis B virus (HBV infection of hepatocytes begins by binding to its cellular receptor sodium taurocholate cotransporting polypeptide (NTCP, followed by the internalization of viral nucleocapsid into the cytoplasm. The viral relaxed circular (rc DNA genome in nucleocapsid is transported into the nucleus and converted into covalently closed circular (ccc DNA to serve as a viral persistence reservoir that is refractory to current antiviral therapies. Host DNA repair enzymes have been speculated to catalyze the conversion of rcDNA to cccDNA, however, the DNA polymerase(s that fills the gap in the plus strand of rcDNA remains to be determined. Here we conducted targeted genetic screening in combination with chemical inhibition to identify the cellular DNA polymerase(s responsible for cccDNA formation, and exploited recombinant HBV with capsid coding deficiency which infects HepG2-NTCP cells with similar efficiency of wild-type HBV to assure cccDNA synthesis is exclusively from de novo HBV infection. We found that DNA polymerase κ (POLK, a Y-family DNA polymerase with maximum activity in non-dividing cells, substantially contributes to cccDNA formation during de novo HBV infection. Depleting gene expression of POLK in HepG2-NTCP cells by either siRNA knockdown or CRISPR/Cas9 knockout inhibited the conversion of rcDNA into cccDNA, while the diminished cccDNA formation in, and hence the viral infection of, the knockout cells could be effectively rescued by ectopic expression of POLK. These studies revealed that POLK is a crucial host factor required for cccDNA formation during a de novo HBV infection and suggest that POLK may be a potential target for developing antivirals against HBV.

Convergence Science in a Nano World

Science.gov (United States)

Cady, Nathaniel

2013-01-01

Convergence is a new paradigm that brings together critical advances in the life sciences, physical sciences and engineering. Going beyond traditional “interdisciplinary” studies, “convergence” describes the culmination of truly integrated research and development, yielding revolutionary advances in both scientific research and new technologies. At its core, nanotechnology embodies these elements of convergence science by bringing together multiple disciplines with the goal of creating innovative and groundbreaking technologies. In the biological and biomedical sciences, nanotechnology research has resulted in dramatic improvements in sensors, diagnostics, imaging, and even therapeutics. In particular, there is a current push to examine the interface between the biological world and micro/nano-scale systems. For example, my laboratory is developing novel strategies for spatial patterning of biomolecules, electrical and optical biosensing, nanomaterial delivery systems, cellular patterning techniques, and the study of cellular interactions with nano-structured surfaces. In this seminar, I will give examples of how convergent research is being applied to three major areas of biological research &endash; cancer diagnostics, microbiology, and DNA-based biosensing. These topics will be presented as case studies, showing the benefits (and challenges) of multi-disciplinary, convergent research and development.

Multiscale properties of DNA primary structure: cross-scale correlations

International Nuclear Information System (INIS)

Altajskij, M.V.; Ivanov, V.V.; Polozov, R.V.

2000-01-01

Cross-scale correlations of wavelet coefficients of the DNA coding sequences are calculated and compared to that of the generated random sequence of the same length. The coding sequences are shown to have strong correlation between large and small scale structures, while random sequences have not

Nano Mechanical Machining Using AFM Probe

Science.gov (United States)

Mostofa, Md. Golam

Complex miniaturized components with high form accuracy will play key roles in the future development of many products, as they provide portability, disposability, lower material consumption in production, low power consumption during operation, lower sample requirements for testing, and higher heat transfer due to their very high surface-to-volume ratio. Given the high market demand for such micro and nano featured components, different manufacturing methods have been developed for their fabrication. Some of the common technologies in micro/nano fabrication are photolithography, electron beam lithography, X-ray lithography and other semiconductor processing techniques. Although these methods are capable of fabricating micro/nano structures with a resolution of less than a few nanometers, some of the shortcomings associated with these methods, such as high production costs for customized products, limited material choices, necessitate the development of other fabricating techniques. Micro/nano mechanical machining, such an atomic force microscope (AFM) probe based nano fabrication, has, therefore, been used to overcome some the major restrictions of the traditional processes. This technique removes material from the workpiece by engaging micro/nano size cutting tool (i.e. AFM probe) and is applicable on a wider range of materials compared to the photolithographic process. In spite of the unique benefits of nano mechanical machining, there are also some challenges with this technique, since the scale is reduced, such as size effects, burr formations, chip adhesions, fragility of tools and tool wear. Moreover, AFM based machining does not have any rotational movement, which makes fabrication of 3D features more difficult. Thus, vibration-assisted machining is introduced into AFM probe based nano mechanical machining to overcome the limitations associated with the conventional AFM probe based scratching method. Vibration-assisted machining reduced the cutting forces

The nano-science of C60 molecule

International Nuclear Information System (INIS)

Rafii-Tabar, H.

2002-01-01

Over the past few years, nano-science and its associated nano-technology have emerged into prominence in research institutions across the world. They have brought about new scientific and engineering paradigms, allowing for the manipulation of single atoms and molecules, designing and fabricating new materials, atom-by-atom, and devices that operate on significantly reduced time and length scales. One important area of research in nano-science and nano technology is carbon-based physics in the form of fullerene physics. The C 6 0 molecule, and other cage-like fullerenes, together with carbon nano tubes provide objects that can be combined to generate three-dimensional functional structures for use in the anticipated nano-technology of future. The unique properties of C 6 0 can also be exploited in designing nano-phase thin films with applications in nano-scope device technology and processes such as nano-lithography. This requires a deep understanding of the highly complex process of adsorption of this molecule on a variety of substrates. We review the field of nano-scale nucleation and growth of C 6 0 molecules on some of the technologically important substrates. In addition to experimental results, the results of a set of highly accurate computational simulations are also reported

Report of International NanoSPD Steering Committee and statistics on recent NanoSPD activities

International Nuclear Information System (INIS)

Valiev, R Z; Langdon, T G

2014-01-01

Abstract. The Université de Lorraine in Metz, France, is the selected site for the 6th International Conference on Nanomaterials by Severe Plastic Deformation (NanoSPD6) following a series of five earlier conferences. This introductory paper reports on several major developments in NanoSPD activities as well as on very recent NanoSPD citation data which confirm the continued growth and expansion of this important research area. Close attention is given to the topics of workshops, conferences and seminars organized during these last three years as well as on books and reviews published prior to the NanoSPD6 conference. A special concern of the committee is in introducing and discussing the appropriate terminology to be applied in this new field of materials science and engineering

Non-linear, non-monotonic effect of nano-scale roughness on particle deposition in absence of an energy barrier: Experiments and modeling

Science.gov (United States)

Jin, Chao; Glawdel, Tomasz; Ren, Carolyn L.; Emelko, Monica B.

2015-12-01

Deposition of colloidal- and nano-scale particles on surfaces is critical to numerous natural and engineered environmental, health, and industrial applications ranging from drinking water treatment to semi-conductor manufacturing. Nano-scale surface roughness-induced hydrodynamic impacts on particle deposition were evaluated in the absence of an energy barrier to deposition in a parallel plate system. A non-linear, non-monotonic relationship between deposition surface roughness and particle deposition flux was observed and a critical roughness size associated with minimum deposition flux or “sag effect” was identified. This effect was more significant for nanoparticles (<1 μm) than for colloids and was numerically simulated using a Convective-Diffusion model and experimentally validated. Inclusion of flow field and hydrodynamic retardation effects explained particle deposition profiles better than when only the Derjaguin-Landau-Verwey-Overbeek (DLVO) force was considered. This work provides 1) a first comprehensive framework for describing the hydrodynamic impacts of nano-scale surface roughness on particle deposition by unifying hydrodynamic forces (using the most current approaches for describing flow field profiles and hydrodynamic retardation effects) with appropriately modified expressions for DLVO interaction energies, and gravity forces in one model and 2) a foundation for further describing the impacts of more complicated scales of deposition surface roughness on particle deposition.

A system approach for reducing the environmental impact of manufacturing and sustainability improvement of nano-scale manufacturing

Science.gov (United States)

Yuan, Yingchun

This dissertation develops an effective and economical system approach to reduce the environmental impact of manufacturing. The system approach is developed by using a process-based holistic method for upstream analysis and source reduction of the environmental impact of manufacturing. The system approach developed consists of three components of a manufacturing system: technology, energy and material, and is useful for sustainable manufacturing as it establishes a clear link between manufacturing system components and its overall sustainability performance, and provides a framework for environmental impact reductions. In this dissertation, the system approach developed is applied for environmental impact reduction of a semiconductor nano-scale manufacturing system, with three case scenarios analyzed in depth on manufacturing process improvement, clean energy supply, and toxic chemical material selection. The analysis on manufacturing process improvement is conducted on Atomic Layer Deposition of Al2O3 dielectric gate on semiconductor microelectronics devices. Sustainability performance and scale-up impact of the ALD technology in terms of environmental emissions, energy consumption, nano-waste generation and manufacturing productivity are systematically investigated and the ways to improve the sustainability of the ALD technology are successfully developed. The clean energy supply is studied using solar photovoltaic, wind, and fuel cells systems for electricity generation. Environmental savings from each clean energy supply over grid power are quantitatively analyzed, and costs for greenhouse gas reductions on each clean energy supply are comparatively studied. For toxic chemical material selection, an innovative schematic method is developed as a visual decision tool for characterizing and benchmarking the human health impact of toxic chemicals, with a case study conducted on six chemicals commonly used as solvents in semiconductor manufacturing. Reliability of

Reduction of DNA damage induced by titanium dioxide nanoparticles through Nrf2 in vitro and in vivo

Energy Technology Data Exchange (ETDEWEB)

Shi, Zhiqin [Department of Toxicology, Hebei Medical University, Shijiazhuang (China); Department of Laboratory Diagnosis, Hebei Medical University, Shijiazhuang (China); Niu, Yujie [Department of Occupational Health and Environmental Health, Hebei Medical University, Shijiazhuang (China); Wang, Qian [Department of Toxicology, Hebei Medical University, Shijiazhuang (China); Shi, Lei [Department of Occupational Health and Environmental Health, Hebei Medical University, Shijiazhuang (China); Guo, Huicai; Liu, Yi; Zhu, Yue [Department of Toxicology, Hebei Medical University, Shijiazhuang (China); Liu, Shufeng; Liu, Chao [Hebei Keylab of Laboratory Animal Science, Shijiazhuang (China); Chen, Xin [Xiumen Community Health Service Centre, Shijiazhuang (China); Zhang, Rong, E-mail: rongzhang@hebmu.edu.cn [Department of Toxicology, Hebei Medical University, Shijiazhuang (China); Hebei Keylab of Laboratory Animal Science, Shijiazhuang (China)

2015-11-15

Highlights: • Nrf2 signals were partly responsible for the DNA damage induced by Nano-TiO{sub 2}. • Nrf2 loss could aggravate the DNA damage induced by Nano-TiO{sub 2}. • Acquired Nrf2 decreased the susceptibility to DNA damage induced by Nano-TiO{sub 2}. - Abstract: Titanium dioxide nanoparticles (Nano-TiO{sub 2}) are widely used to additives in cosmetics, pharmaceutical, paints and foods. Recent studies have demonstrated that Nano-TiO{sub 2} induces DNA damage and increased the risk of cancer and the mechanism might relate with oxidative stress. The aim of this study was to evaluate the effects of Nuclear factor erythroid 2 (NF-E2)-related factor 2 (Nrf2), an anti-oxidative mediator, on DNA damage induced by Nano-TiO{sub 2}. Wildtype, Nrf2 knockout (Nrf2(-/-)) and tert-butylhydroquinone (tBHQ) pre-treated HepG2 cells and mice were treated with Nano-TiO{sub 2}. And then the oxidative stress and DNA damage were evaluated. Our data showed that DNA damage, reactive oxygen species (ROS) generation and MDA content in Nano-TiO{sub 2} exposed cells were significantly increased than those of control in dose dependent manners. Nrf2/ARE droved the downstream genes including NAD(P)H dehydrogenase [quinine] 1(NQO1), heme oxygenase 1 (HO-1) and glutamate-cysteine ligase catalytic subunit (GCLC) expression were significantly higher in wildtype HepG2 cells after Nano-TiO{sub 2} treatment. After treatment with Nano-TiO{sub 2}, the DNA damages were significantly increased in Nrf(-/-) cells and mice whereas significantly decreased in tBHQ pre-treatment cells and mice, compared with the wildtype HepG2 cells and mice, respectively. Our results indicated that the acquired of Nrf2 leads to a decreased susceptibility to DNA damages induction by Nano-TiO{sub 2} and decreasing of risk of cancer which would provide a strategy for a more efficacious sensitization of against of Nano-TiO{sub 2} toxication.

Advancing nanoelectronic device modeling through peta-scale computing and deployment on nanoHUB

International Nuclear Information System (INIS)

Haley, Benjamin P; Luisier, Mathieu; Klimeck, Gerhard; Lee, Sunhee; Ryu, Hoon; Bae, Hansang; Saied, Faisal; Clark, Steve

2009-01-01

Recent improvements to existing HPC codes NEMO 3-D and OMEN, combined with access to peta-scale computing resources, have enabled realistic device engineering simulations that were previously infeasible. NEMO 3-D can now simulate 1 billion atom systems, and, using 3D spatial decomposition, scale to 32768 cores. Simulation time for the band structure of an experimental P doped Si quantum computing device fell from 40 minutes to 1 minute. OMEN can perform fully quantum mechanical transport calculations for real-word UTB FETs on 147,456 cores in roughly 5 minutes. Both of these tools power simulation engines on the nanoHUB, giving the community access to previously unavailable research capabilities.

Structure and tensile properties of Fe-Cr model alloy strengthened by nano-scale NbC particles derived from controlled crystallization of Nb-rich clusters

Energy Technology Data Exchange (ETDEWEB)

Dai, Lei [College of Materials and Chemical Engineering, Three Gorges University, Yichang 443002 (China); Guo, Qianying [State Key Lab of Hydraulic Engineering Simulation and Safety, School of Material Science and Engineering, Tianjin University, Tianjin 300354 (China); Liu, Yongchang, E-mail: licmtju@163.com [State Key Lab of Hydraulic Engineering Simulation and Safety, School of Material Science and Engineering, Tianjin University, Tianjin 300354 (China); Yu, Liming; Li, Huijun [State Key Lab of Hydraulic Engineering Simulation and Safety, School of Material Science and Engineering, Tianjin University, Tianjin 300354 (China)

2016-09-30

This article describes the microstructural evolution and tensile properties of Fe-Cr model alloy strengthened by nano-scale NbC particles. According to the results obtained from X-ray diffraction and transmission electron microscope with Energy Dispersive Spectrometer, the bcc ultrafine grains and the disordered phase of Nb-rich nano-clusters were observed in the milled powders. The hot pressing (HP) resulted in a nearly equiaxed ferritic grains and dispersed nano-scale NbC (~8 nm) particles. The microstructure studies reveal that the formation of NbC nanoparticles is composed of nucleation and growth of the Nb-rich nano-clusters involving diffusion of their component. At room temperature the material exhibits an ultimate tensile strength of 700 MPa, yield strength of 650 MPa, and total elongation of 11.7 pct. The fracture surface studies reveal that a typical ductile fracture mode has occurred during tensile test.

Large-scale chromosome folding versus genomic DNA sequences: A discrete double Fourier transform technique.

Science.gov (United States)

Chechetkin, V R; Lobzin, V V

2017-08-07

Using state-of-the-art techniques combining imaging methods and high-throughput genomic mapping tools leaded to the significant progress in detailing chromosome architecture of various organisms. However, a gap still remains between the rapidly growing structural data on the chromosome folding and the large-scale genome organization. Could a part of information on the chromosome folding be obtained directly from underlying genomic DNA sequences abundantly stored in the databanks? To answer this question, we developed an original discrete double Fourier transform (DDFT). DDFT serves for the detection of large-scale genome regularities associated with domains/units at the different levels of hierarchical chromosome folding. The method is versatile and can be applied to both genomic DNA sequences and corresponding physico-chemical parameters such as base-pairing free energy. The latter characteristic is closely related to the replication and transcription and can also be used for the assessment of temperature or supercoiling effects on the chromosome folding. We tested the method on the genome of E. coli K-12 and found good correspondence with the annotated domains/units established experimentally. As a brief illustration of further abilities of DDFT, the study of large-scale genome organization for bacteriophage PHIX174 and bacterium Caulobacter crescentus was also added. The combined experimental, modeling, and bioinformatic DDFT analysis should yield more complete knowledge on the chromosome architecture and genome organization. Copyright © 2017 Elsevier Ltd. All rights reserved.

Titanium dioxide nanoparticles activate the ATM-Chk2 DNA damage response in human dermal fibroblasts

Science.gov (United States)

Prasad, Raju Y.; Chastain, Paul D.; Nikolaishvili-Feinberg, Nana; Smeester, Lisa M.; Kaufmann, William K.; Fry, Rebecca C.

2013-01-01

The use of nanoparticles in consumer products increases their prevalence in the environment and the potential risk to human health. Although recent studies have shown in vivo and in vitro toxicity of titanium dioxide nanoparticles (nano-TiO2), a more detailed view of the underlying mechanisms of this response needs to be established. Here the effects of nano-TiO2 on the DNA damage response and DNA replication dynamics were investigated in human dermal fibroblasts. Specifically, the relationship between nano-TiO2 and the DNA damage response pathways regulated by ATM/Chk2 and ATR/Chk1 were examined. The results show increased phosphorylation of H2AX, ATM, and Chk2 after exposure. In addition, nano-TiO2 inhibited the overall rate of DNA synthesis and frequency of replicon initiation events in DNA combed fibers. Taken together, these results demonstrate that exposure to nano-TiO2 activates the ATM/Chk2 DNA damage response pathway. PMID:22770119

Large-scale DNA Barcode Library Generation for Biomolecule Identification in High-throughput Screens.

Science.gov (United States)

Lyons, Eli; Sheridan, Paul; Tremmel, Georg; Miyano, Satoru; Sugano, Sumio

2017-10-24

High-throughput screens allow for the identification of specific biomolecules with characteristics of interest. In barcoded screens, DNA barcodes are linked to target biomolecules in a manner allowing for the target molecules making up a library to be identified by sequencing the DNA barcodes using Next Generation Sequencing. To be useful in experimental settings, the DNA barcodes in a library must satisfy certain constraints related to GC content, homopolymer length, Hamming distance, and blacklisted subsequences. Here we report a novel framework to quickly generate large-scale libraries of DNA barcodes for use in high-throughput screens. We show that our framework dramatically reduces the computation time required to generate large-scale DNA barcode libraries, compared with a naїve approach to DNA barcode library generation. As a proof of concept, we demonstrate that our framework is able to generate a library consisting of one million DNA barcodes for use in a fragment antibody phage display screening experiment. We also report generating a general purpose one billion DNA barcode library, the largest such library yet reported in literature. Our results demonstrate the value of our novel large-scale DNA barcode library generation framework for use in high-throughput screening applications.

Nano market and analysis of technology

International Nuclear Information System (INIS)

2001-10-01

This book gives descriptions of summary of nano technology with meaning, character and field, trend of technical development in domestic, current condition of nano basic research in domestic, trend of technical development in foreign country such as summary, trend of technology by industrial field, machine and metronics, material and process, standard of nano mechanism, scale of market and trend, competitiveness of nano technology of major country and research development system in Japan, Korean company and major countries.

The Effect of DNA and Sodium Cholate Dispersed Single-Walled Carbon Nano tubes on the Green Algae Chlamydomonas reinhardtii

International Nuclear Information System (INIS)

Williams, R.M.; Cox, Z.; Dolash, B.D.; Sooter, L.J.; Williams, R.M.; Taylor, H.K.; Thomas, J.

2014-01-01

Increasing use of single-walled carbon nano tubes (SWCNTs) will lead to their increased release into the environment. Previous work has shown negative effects of SWCNT on growth and survival of model organisms. The aim of the current study was to determine the effect of SWCNT well-dispersed by either DNA or sodium cholate (SC) on the unicellular green algae Chlamydomonas reinhardtii in stagnant water conditions. Growth measurements were taken up to ten days for algae treated with varied levels of DNA:SWCNT or SC:SWCNT or controls, and chlorophyll content after 10 days was determined. Results show no effect on either growth or chlorophyll content of algae at any concentration or duration. This is in contradiction to prior work showing toxicity of SWCNT to environmental model organisms.

Bottom-Up Nano-heteroepitaxy of Wafer-Scale Semipolar GaN on (001) Si

KAUST Repository

Hus, Jui Wei

2015-07-15

Semipolar {101¯1} InGaN quantum wells are grown on (001) Si substrates with an Al-free buffer and wafer-scale uniformity. The novel structure is achieved by a bottom-up nano-heteroepitaxy employing self-organized ZnO nanorods as the strain-relieving layer. This ZnO nanostructure unlocks the problems encountered by the conventional AlN-based buffer, which grows slowly and contaminates the growth chamber. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

DLC nano-dot surfaces for tribological applications in MEMS devices

Energy Technology Data Exchange (ETDEWEB)

Singh, R. Arvind; Na, Kyounghwan [Nano-Bio Research Center, Korea Institute of Science and Technology, 39-1, Hawolgok-dong, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Yi, Jin Woo; Lee, Kwang-Ryeol [Computational Science Center, Korea Institute of Science and Technology, 39-1, Hawolgok-dong, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Yoon, Eui-Sung, E-mail: esyoon@kist.re.kr [Nano-Bio Research Center, Korea Institute of Science and Technology, 39-1, Hawolgok-dong, Seongbuk-gu, Seoul 136-791 (Korea, Republic of)

2011-02-01

With the invention of miniaturized devices like micro-electro-mechanical systems (MEMS), tribological studies at micro/nano-scale have gained importance. These studies are directed towards understanding the interactions between surfaces at micro/nano-scales, under relative motion. In MEMS devices, the critical forces, namely adhesion and friction restrict the smooth operation of the elements that are in relative motion. These miniaturized devices are traditionally made from silicon (Si), whose tribological properties are not good. In this paper, we present a short investigation of nano- and micro-tribological properties of diamond-like carbon (DLC) nano-dot surfaces. The investigation was undertaken to evaluate the potential of these surfaces for their possible application to the miniaturized devices. The tribological evaluation of the DLC nano-dot surfaces was done in comparison with bare Si (1 0 0) surfaces and DLC coated silicon surfaces. A commercial atomic force microscope (AFM) was used to measure adhesion and friction properties of the test materials at the nano-scale, whereas a custom-built micro-tribotester was used to measure their micro-friction property. Results showed that the DLC nano-dot surfaces exhibited superior tribological properties with the lowest values of adhesion force, and friction force both at the nano- and micro-scales, when compared to the bare Si (1 0 0) surfaces and DLC coated silicon surfaces. In addition, the DLC nano-dot surfaces showed no observable wear at the micro-scale, unlike the other two test materials. The superior tribological performance of the DLC nano-dot surfaces is attributed to their hydrophobic nature and the reduced area of contact projected by them.

DLC nano-dot surfaces for tribological applications in MEMS devices

International Nuclear Information System (INIS)

Singh, R. Arvind; Na, Kyounghwan; Yi, Jin Woo; Lee, Kwang-Ryeol; Yoon, Eui-Sung

2011-01-01

With the invention of miniaturized devices like micro-electro-mechanical systems (MEMS), tribological studies at micro/nano-scale have gained importance. These studies are directed towards understanding the interactions between surfaces at micro/nano-scales, under relative motion. In MEMS devices, the critical forces, namely adhesion and friction restrict the smooth operation of the elements that are in relative motion. These miniaturized devices are traditionally made from silicon (Si), whose tribological properties are not good. In this paper, we present a short investigation of nano- and micro-tribological properties of diamond-like carbon (DLC) nano-dot surfaces. The investigation was undertaken to evaluate the potential of these surfaces for their possible application to the miniaturized devices. The tribological evaluation of the DLC nano-dot surfaces was done in comparison with bare Si (1 0 0) surfaces and DLC coated silicon surfaces. A commercial atomic force microscope (AFM) was used to measure adhesion and friction properties of the test materials at the nano-scale, whereas a custom-built micro-tribotester was used to measure their micro-friction property. Results showed that the DLC nano-dot surfaces exhibited superior tribological properties with the lowest values of adhesion force, and friction force both at the nano- and micro-scales, when compared to the bare Si (1 0 0) surfaces and DLC coated silicon surfaces. In addition, the DLC nano-dot surfaces showed no observable wear at the micro-scale, unlike the other two test materials. The superior tribological performance of the DLC nano-dot surfaces is attributed to their hydrophobic nature and the reduced area of contact projected by them.

Tribological study on rapeseed oil with nano-additives in close contact sliding situation

Science.gov (United States)

Gupta, Rajeev Nayan; Harsha, A. P.; Singh, Sagar

2018-02-01

The present work deals with the tribological evaluation of three types of nano-additives, i.e., copper oxide (CuO; ≈ 151.2 nm), cerium oxide (CeO2; ≈ 80 nm) and polytetrafluoroethylene (PTFE; ≈ 90.4 nm) with rapeseed oil under steel-steel sliding contacts. The nano-additives concentrations in the base oil were 0.1, 0.25 and 0.5% w/v for the lubricant formulation. Further, the rapeseed oil was also epoxidized by a chemical method and the tribological behavior was compared with the base oil (unmodified oil) at similar nano-additives concentrations. The ASTM standards were followed for the study of wear preventive and extreme-pressure analysis of nanolubricants, and it was carried out using four-ball tester. In the antiwear test, CeO2 and PTFE nano-additives have shown the significant reduction in the wear scar diameter at the concentration of 0.1% w/v. In the extreme-pressure test, 0.5% w/v concentration was optimum for oxide nanoparticles; however, PTFE nanoparticles did not show positive effect with both the base oils. Different characterization techniques were employed to confirm the oil modification and for the study of the worn surfaces.

Analysis of the nano-scale structure of a natural clayey soil using the small angle neutron scattering method

International Nuclear Information System (INIS)

Itakura, T.; Bertram, W.K.; Hathaway, P.V.; Knott, R.B.

2001-01-01

The small angle neutron scattering method (SANS) was used to analyze the nano-structure of a natural clayey soil used for containment of industrial liquid wastes. A Tertiary clay deposit called the Londonderry clay was used to contain the wastes in a state-run landfill facility in NSW. A number of site assessments have been carried out at the site and continual efforts have been made to characterize interactions between soil materials and contaminants at the site. Hence, it is of research and practical interest to investigate the effects of deformation on the nano-scale structure of the soil. Experiments have been conducted to analyze the structure of reconstituted clayey soil samples that were subjected to uniaxial compression ranging from 200 kPa to 800 kPa. The small angle neutron scattering instrument was used to measure the scattering intensity of these samples at a scattering vector (q) range between 0.01 and 0.1 Angstroms -1 . The sector integration technique was used to analyse elliptical scattering patterns along the major and minor axes. A relation between stress, void ratio and nano-scale structure properties was then briefly discussed for use in assessing the performance of clayey soils as in situ barriers

Micro-and/or nano-scale patterned porous membranes, methods of making membranes, and methods of using membranes

KAUST Repository

Wang, Xianbin; Chen, Wei; Wang, Zhihong; Zhang, Xixiang; Yue, Weisheng; Lai, Zhiping

2015-01-01

Embodiments of the present disclosure provide for materials that include a pre-designed patterned, porous membrane (e.g., micro- and/or nano-scale patterned), structures or devices that include a pre-designed patterned, porous membrane, methods of making pre-designed patterned, porous membranes, methods of separation, and the like.

Micro-and/or nano-scale patterned porous membranes, methods of making membranes, and methods of using membranes

KAUST Repository

Wang, Xianbin

2015-01-22

Embodiments of the present disclosure provide for materials that include a pre-designed patterned, porous membrane (e.g., micro- and/or nano-scale patterned), structures or devices that include a pre-designed patterned, porous membrane, methods of making pre-designed patterned, porous membranes, methods of separation, and the like.

Self-assembled DNA Structures for Nanoconstruction

Science.gov (United States)

Yan, Hao; Yin, Peng; Park, Sung Ha; Li, Hanying; Feng, Liping; Guan, Xiaoju; Liu, Dage; Reif, John H.; LaBean, Thomas H.

2004-09-01

In recent years, a number of research groups have begun developing nanofabrication methods based on DNA self-assembly. Here we review our recent experimental progress to utilize novel DNA nanostructures for self-assembly as well as for templates in the fabrication of functional nano-patterned materials. We have prototyped a new DNA nanostructure known as a cross structure. This nanostructure has a 4-fold symmetry which promotes its self-assembly into tetragonal 2D lattices. We have utilized the tetragonal 2D lattices as templates for highly conductive metallic nanowires and periodic 2D protein nano-arrays. We have constructed and characterized a DNA nanotube, a new self-assembling superstructure composed of DNA tiles. We have also demonstrated an aperiodic DNA lattice composed of DNA tiles assembled around a long scaffold strand; the system translates information encoded in the scaffold strand into a specific and reprogrammable barcode pattern. We have achieved metallic nanoparticle linear arrays templated on self-assembled 1D DNA arrays. We have designed and demonstrated a 2-state DNA lattice, which displays expand/contract motion switched by DNA nanoactuators. We have also achieved an autonomous DNA motor executing unidirectional motion along a linear DNA track.

Controlled heat flux measurement across a closing nanoscale gap and its comparison to theory

Energy Technology Data Exchange (ETDEWEB)

Ma, Y.; Ghafari, A.; Budaev, B. V.; Bogy, D. B., E-mail: dbogy@berkeley.edu [Department of mechanical Engineering, Computer Mechanics Lab, University of California, Berkeley, California 94720 (United States)

2016-05-23

We present here a controlled measurement of heat flux across a closing gap that is initially less than 10 nm wide between two solid surfaces at different temperatures. The measured heat transfer is compared with our published theoretical analyses of this phenomenon that show thermal radiation dominates the heat transfer for gaps wider than about 1–2 nm, but phonon conduction dominates between 1 and 2 nm and contact. The experiments employ a thermal actuator mounted on a rocking base block for coarse positioning that supplies Joule heating to an embedded element to cause thermal expansion of a localized region for less than 10 nm spacing control, together with an embedded near-surface resistive temperature sensor to measure its temperature change due to the heat flux across the gap. The measured results are in general agreement with the theoretical predictions, and they also agree with common sense expectations. This paper not only shows nano-scale heat transfer measurement across a closing gap, it also lends additional strong support to the validity of the referenced theoretical developments. The proposed experimental approach can provide support to design of future devices for nano-scale heat transfer measurement.

Nano materials for Renewable Energy Storage: Synthesis, Characterization, and Applications

International Nuclear Information System (INIS)

Rather, S.U.; Zacharia, R.; Stephan, A.M.; Petrov, L.A.; Nair, J.R.

2015-01-01

Nano technology and nano scale materials have been part of human history and in use since centuries. Staining of glass windows hundreds of years ago is one of the examples where people created beautiful works without knowing that they are using nano processing. The beginning of modern era of nano technology dates back to the talk of the Nobel laureate Professor Richard Feynman in There plenty of room at the bottom. Professor Feynman hypothesized that in near future scientists would be able to control and modulate individual molecules and atoms. After a decade, Professor Norio Taniguchi introduced the magical word nano technology. However, in 1981, the introduction of scanning tunnelling microscope enabled the scientists to see the materials in nano scale that propagated the new age of nano technology.

Dimensional micro and nano metrology

DEFF Research Database (Denmark)

Hansen, Hans Nørgaard; da Costa Carneiro, Kim; Haitjema, Han

2006-01-01

The need for dimensional micro and nano metrology is evident, and as critical dimensions are scaled down and geometrical complexity of objects is increased, the available technologies appear not sufficient. Major research and development efforts have to be undertaken in order to answer these chal......The need for dimensional micro and nano metrology is evident, and as critical dimensions are scaled down and geometrical complexity of objects is increased, the available technologies appear not sufficient. Major research and development efforts have to be undertaken in order to answer...... these challenges. The developments have to include new measuring principles and instrumentation, tolerancing rules and procedures as well as traceability and calibration. The current paper describes issues and challenges in dimensional micro and nano metrology by reviewing typical measurement tasks and available...

Solid-to-fluid DNA transition inside HSV-1 capsid close to the temperature of infection

Energy Technology Data Exchange (ETDEWEB)

Sae-Ueng, Udom; Li, Dong; Zuo, Xiaobing; Huffman, Jamie B.; Homa, Fred L.; Rau, Donald; Evilevitch, Alex

2014-10-01

DNA in the human Herpes simplex virus type 1 (HSV-1) capsid is packaged to a tight density. This leads to tens of atmospheres of internal pressure responsible for the delivery of the herpes genome into the cell nucleus. In this study we show that, despite its liquid crystalline state inside the capsid, the DNA is fluid-like, which facilitates its ejection into the cell nucleus during infection. We found that the sliding friction between closely packaged DNA strands, caused by interstrand repulsive interactions, is reduced by the ionic environment of epithelial cells and neurons susceptible to herpes infection. However, variations in the ionic conditions corresponding to neuronal activity can restrict DNA mobility in the capsid, making it more solid-like. This can inhibit intranuclear DNA release and interfere with viral replication. In addition, the temperature of the human host (37 °C) induces a disordering transition of the encapsidated herpes genome, which reduces interstrand interactions and provides genome mobility required for infection.

Uracil DNA glycosylase counteracts APOBEC3G-induced hypermutation of hepatitis B viral genomes: excision repair of covalently closed circular DNA.

Directory of Open Access Journals (Sweden)

Kouichi Kitamura

Full Text Available The covalently closed circular DNA (cccDNA of the hepatitis B virus (HBV plays an essential role in chronic hepatitis. The cellular repair system is proposed to convert cytoplasmic nucleocapsid (NC DNA (partially double-stranded DNA into cccDNA in the nucleus. Recently, antiviral cytidine deaminases, AID/APOBEC proteins, were shown to generate uracil residues in the NC-DNA through deamination, resulting in cytidine-to-uracil (C-to-U hypermutation of the viral genome. We investigated whether uracil residues in hepadnavirus DNA were excised by uracil-DNA glycosylase (UNG, a host factor for base excision repair (BER. When UNG activity was inhibited by the expression of the UNG inhibitory protein (UGI, hypermutation of NC-DNA induced by either APOBEC3G or interferon treatment was enhanced in a human hepatocyte cell line. To assess the effect of UNG on the cccDNA viral intermediate, we used the duck HBV (DHBV replication model. Sequence analyses of DHBV DNAs showed that cccDNA accumulated G-to-A or C-to-T mutations in APOBEC3G-expressing cells, and this was extensively enhanced by UNG inhibition. The cccDNA hypermutation generated many premature stop codons in the P gene. UNG inhibition also enhanced the APOBEC3G-mediated suppression of viral replication, including reduction of NC-DNA, pre-C mRNA, and secreted viral particle-associated DNA in prolonged culture. Enhancement of APOBEC3G-mediated suppression by UNG inhibition was not observed when the catalytic site of APOBEC3G was mutated. Transfection experiments of recloned cccDNAs revealed that the combination of UNG inhibition and APOBEC3G expression reduced the replication ability of cccDNA. Taken together, these data indicate that UNG excises uracil residues from the viral genome during or after cccDNA formation in the nucleus and imply that BER pathway activities decrease the antiviral effect of APOBEC3-mediated hypermutation.

Gigadalton-scale shape-programmable DNA assemblies

Science.gov (United States)

Wagenbauer, Klaus F.; Sigl, Christian; Dietz, Hendrik

2017-12-01

Natural biomolecular assemblies such as molecular motors, enzymes, viruses and subcellular structures often form by self-limiting hierarchical oligomerization of multiple subunits. Large structures can also assemble efficiently from a few components by combining hierarchical assembly and symmetry, a strategy exemplified by viral capsids. De novo protein design and RNA and DNA nanotechnology aim to mimic these capabilities, but the bottom-up construction of artificial structures with the dimensions and complexity of viruses and other subcellular components remains challenging. Here we show that natural assembly principles can be combined with the methods of DNA origami to produce gigadalton-scale structures with controlled sizes. DNA sequence information is used to encode the shapes of individual DNA origami building blocks, and the geometry and details of the interactions between these building blocks then control their copy numbers, positions and orientations within higher-order assemblies. We illustrate this strategy by creating planar rings of up to 350 nanometres in diameter and with atomic masses of up to 330 megadaltons, micrometre-long, thick tubes commensurate in size to some bacilli, and three-dimensional polyhedral assemblies with sizes of up to 1.2 gigadaltons and 450 nanometres in diameter. We achieve efficient assembly, with yields of up to 90 per cent, by using building blocks with validated structure and sufficient rigidity, and an accurate design with interaction motifs that ensure that hierarchical assembly is self-limiting and able to proceed in equilibrium to allow for error correction. We expect that our method, which enables the self-assembly of structures with sizes approaching that of viruses and cellular organelles, can readily be used to create a range of other complex structures with well defined sizes, by exploiting the modularity and high degree of addressability of the DNA origami building blocks used.

Water soluble nano-scale transient material germanium oxide for zero toxic waste based environmentally benign nano-manufacturing

KAUST Repository

Almuslem, A. S.

2017-02-14

In the recent past, with the advent of transient electronics for mostly implantable and secured electronic applications, the whole field effect transistor structure has been dissolved in a variety of chemicals. Here, we show simple water soluble nano-scale (sub-10 nm) germanium oxide (GeO) as the dissolvable component to remove the functional structures of metal oxide semiconductor devices and then reuse the expensive germanium substrate again for functional device fabrication. This way, in addition to transiency, we also show an environmentally friendly manufacturing process for a complementary metal oxide semiconductor (CMOS) technology. Every year, trillions of complementary metal oxide semiconductor (CMOS) electronics are manufactured and billions are disposed, which extend the harmful impact to our environment. Therefore, this is a key study to show a pragmatic approach for water soluble high performance electronics for environmentally friendly manufacturing and bioresorbable electronic applications.

Handbook of damage mechanics nano to macro scale for materials and structures

CERN Document Server

2015-01-01

This authoritative reference provides comprehensive coverage of the topics of damage and healing mechanics. Computational modeling of constitutive equations is provided as well as solved examples in engineering applications. A wide range of materials that engineers may encounter are covered, including metals, composites, ceramics, polymers, biomaterials, and nanomaterials. The internationally recognized team of contributors employ a consistent and systematic approach, offering readers a user-friendly reference that is ideal for frequent consultation. Handbook of Damage Mechanics: Nano to Macro Scale for Materials and Structures is ideal for graduate students and faculty, researchers, and professionals in the fields of Mechanical Engineering, Civil Engineering, Aerospace Engineering, Materials Science, and Engineering Mechanics.

Probing properties, stability, and performances of hierarchical meso-porous materials with nano-scale interfaces

International Nuclear Information System (INIS)

Baldinozzi, Gianguido; Gosset, Dominique; Simeone, David; Muller, Guillaume; Laberty-Robert, Christel; Sanchez, Clement

2012-01-01

Nano-crystals growth mechanism embedded into meso-porous thin films has been determined directly from grazing incidence X-ray diffraction data. We have shown, for the first time, that surface capillary forces control the growth mechanism of nano-crystals into these nano-architectures. Moreover, these data allow an estimation of the surface tension of the nano-crystals organized into a 3-D nano-architecture. The analysis of the variations in the strain field of these nano-crystals gives information on the evolution of the microstructure of these meso-porous films, that is, the contacts among nano-crystals. This work represents the first application of grazing incidence X-ray for understanding stability and performances of meso-porous thin films. This approach can be used to understand the structural stability of these nano-architectures at high temperature. (authors)

Is there an optimal topographical surface in nano-scale affecting protein adsorption and cell behaviors? Part II

Energy Technology Data Exchange (ETDEWEB)

Wang Huajie, E-mail: wanghuajie972001@163.com; Sun Yuanyuan; Cao Ying, E-mail: caoying1130@sina.com; Wang Kui; Yang Lin [Henan Normal University, College of Chemistry and Environmental Science (China); Zhang Yidong; Zheng Zhi [Xuchang University, Institute of Surface Micro and Nano Materials (China)

2012-05-15

Although nano-structured surfaces exhibit superior biological activities to the smooth or micro-structured surfaces, whether there is an optimal topographical surface in nano-scale affecting protein adsorption and cell behaviors is still controversial. In this study, porous aluminum oxide membranes with different pore sizes ranging from 25 to 120 nm were prepared by the anodic oxidation technique. The surface morphology, topography and wettability were analyzed by scanning electron microscope, atomic force microscope and water contact angle measurement, respectively. The results indicated that the synergistic action of the nano-topography structure and hydrophilic/hydrophobic properties resulted in a highest protein adsorption on the aluminum oxide membrane with 80 nm pore size. Additionally, the morphological, metabolic and cell counting methods showed that cells had different sensitivity to porous aluminum oxide membranes with different surface features. Furthermore, this sensitivity was cell type dependent. The optimal pore size of aluminum oxide membranes for cell growth was 80 nm for PC12 cells and 50 nm for NIH 3T3 cells.

Emergence of scale-free close-knit friendship structure in online social networks.

Directory of Open Access Journals (Sweden)

Ai-Xiang Cui

Full Text Available Although the structural properties of online social networks have attracted much attention, the properties of the close-knit friendship structures remain an important question. Here, we mainly focus on how these mesoscale structures are affected by the local and global structural properties. Analyzing the data of four large-scale online social networks reveals several common structural properties. It is found that not only the local structures given by the indegree, outdegree, and reciprocal degree distributions follow a similar scaling behavior, the mesoscale structures represented by the distributions of close-knit friendship structures also exhibit a similar scaling law. The degree correlation is very weak over a wide range of the degrees. We propose a simple directed network model that captures the observed properties. The model incorporates two mechanisms: reciprocation and preferential attachment. Through rate equation analysis of our model, the local-scale and mesoscale structural properties are derived. In the local-scale, the same scaling behavior of indegree and outdegree distributions stems from indegree and outdegree of nodes both growing as the same function of the introduction time, and the reciprocal degree distribution also shows the same power-law due to the linear relationship between the reciprocal degree and in/outdegree of nodes. In the mesoscale, the distributions of four closed triples representing close-knit friendship structures are found to exhibit identical power-laws, a behavior attributed to the negligible degree correlations. Intriguingly, all the power-law exponents of the distributions in the local-scale and mesoscale depend only on one global parameter, the mean in/outdegree, while both the mean in/outdegree and the reciprocity together determine the ratio of the reciprocal degree of a node to its in/outdegree. Structural properties of numerical simulated networks are analyzed and compared with each of the four

Emergence of scale-free close-knit friendship structure in online social networks.

Science.gov (United States)

Cui, Ai-Xiang; Zhang, Zi-Ke; Tang, Ming; Hui, Pak Ming; Fu, Yan

2012-01-01

Although the structural properties of online social networks have attracted much attention, the properties of the close-knit friendship structures remain an important question. Here, we mainly focus on how these mesoscale structures are affected by the local and global structural properties. Analyzing the data of four large-scale online social networks reveals several common structural properties. It is found that not only the local structures given by the indegree, outdegree, and reciprocal degree distributions follow a similar scaling behavior, the mesoscale structures represented by the distributions of close-knit friendship structures also exhibit a similar scaling law. The degree correlation is very weak over a wide range of the degrees. We propose a simple directed network model that captures the observed properties. The model incorporates two mechanisms: reciprocation and preferential attachment. Through rate equation analysis of our model, the local-scale and mesoscale structural properties are derived. In the local-scale, the same scaling behavior of indegree and outdegree distributions stems from indegree and outdegree of nodes both growing as the same function of the introduction time, and the reciprocal degree distribution also shows the same power-law due to the linear relationship between the reciprocal degree and in/outdegree of nodes. In the mesoscale, the distributions of four closed triples representing close-knit friendship structures are found to exhibit identical power-laws, a behavior attributed to the negligible degree correlations. Intriguingly, all the power-law exponents of the distributions in the local-scale and mesoscale depend only on one global parameter, the mean in/outdegree, while both the mean in/outdegree and the reciprocity together determine the ratio of the reciprocal degree of a node to its in/outdegree. Structural properties of numerical simulated networks are analyzed and compared with each of the four real networks. This

DNA Qualification Workflow for Next Generation Sequencing of Histopathological Samples

Science.gov (United States)

Simbolo, Michele; Gottardi, Marisa; Corbo, Vincenzo; Fassan, Matteo; Mafficini, Andrea; Malpeli, Giorgio; Lawlor, Rita T.; Scarpa, Aldo

2013-01-01

Histopathological samples are a treasure-trove of DNA for clinical research. However, the quality of DNA can vary depending on the source or extraction method applied. Thus a standardized and cost-effective workflow for the qualification of DNA preparations is essential to guarantee interlaboratory reproducible results. The qualification process consists of the quantification of double strand DNA (dsDNA) and the assessment of its suitability for downstream applications, such as high-throughput next-generation sequencing. We tested the two most frequently used instrumentations to define their role in this process: NanoDrop, based on UV spectroscopy, and Qubit 2.0, which uses fluorochromes specifically binding dsDNA. Quantitative PCR (qPCR) was used as the reference technique as it simultaneously assesses DNA concentration and suitability for PCR amplification. We used 17 genomic DNAs from 6 fresh-frozen (FF) tissues, 6 formalin-fixed paraffin-embedded (FFPE) tissues, 3 cell lines, and 2 commercial preparations. Intra- and inter-operator variability was negligible, and intra-methodology variability was minimal, while consistent inter-methodology divergences were observed. In fact, NanoDrop measured DNA concentrations higher than Qubit and its consistency with dsDNA quantification by qPCR was limited to high molecular weight DNA from FF samples and cell lines, where total DNA and dsDNA quantity virtually coincide. In partially degraded DNA from FFPE samples, only Qubit proved highly reproducible and consistent with qPCR measurements. Multiplex PCR amplifying 191 regions of 46 cancer-related genes was designated the downstream application, using 40 ng dsDNA from FFPE samples calculated by Qubit. All but one sample produced amplicon libraries suitable for next-generation sequencing. NanoDrop UV-spectrum verified contamination of the unsuccessful sample. In conclusion, as qPCR has high costs and is labor intensive, an alternative effective standard workflow for

DNA qualification workflow for next generation sequencing of histopathological samples.

Directory of Open Access Journals (Sweden)

Michele Simbolo

Full Text Available Histopathological samples are a treasure-trove of DNA for clinical research. However, the quality of DNA can vary depending on the source or extraction method applied. Thus a standardized and cost-effective workflow for the qualification of DNA preparations is essential to guarantee interlaboratory reproducible results. The qualification process consists of the quantification of double strand DNA (dsDNA and the assessment of its suitability for downstream applications, such as high-throughput next-generation sequencing. We tested the two most frequently used instrumentations to define their role in this process: NanoDrop, based on UV spectroscopy, and Qubit 2.0, which uses fluorochromes specifically binding dsDNA. Quantitative PCR (qPCR was used as the reference technique as it simultaneously assesses DNA concentration and suitability for PCR amplification. We used 17 genomic DNAs from 6 fresh-frozen (FF tissues, 6 formalin-fixed paraffin-embedded (FFPE tissues, 3 cell lines, and 2 commercial preparations. Intra- and inter-operator variability was negligible, and intra-methodology variability was minimal, while consistent inter-methodology divergences were observed. In fact, NanoDrop measured DNA concentrations higher than Qubit and its consistency with dsDNA quantification by qPCR was limited to high molecular weight DNA from FF samples and cell lines, where total DNA and dsDNA quantity virtually coincide. In partially degraded DNA from FFPE samples, only Qubit proved highly reproducible and consistent with qPCR measurements. Multiplex PCR amplifying 191 regions of 46 cancer-related genes was designated the downstream application, using 40 ng dsDNA from FFPE samples calculated by Qubit. All but one sample produced amplicon libraries suitable for next-generation sequencing. NanoDrop UV-spectrum verified contamination of the unsuccessful sample. In conclusion, as qPCR has high costs and is labor intensive, an alternative effective standard

Electrode fabrication for Lithium-ion batteries by intercalating of carbon nano tubes inside nano metric pores of silver foam

International Nuclear Information System (INIS)

Khoshnevisan, B.

2011-01-01

Here there is an on effort to improve working electrode (Ag + carbon nano tubes) preparation for Li-Ion batteries applications. Nano scaled silver foam with high specific area has been employed as a frame for loading carbon nano tubes by electrophoretic deposition method. In this ground, the prepared electrodes show a very good stability and also charge-discharge cycles reversibility.

Plasmonic-cavity model for radiating nano-rod antennas

DEFF Research Database (Denmark)

Peng, Liang; Mortensen, N. Asger

2014-01-01

In this paper, we propose the analytical solution of nano-rod antennas utilizing a cylindrical harmonics expansion. By treating the metallic nano-rods as plasmonic cavities, we derive closed-form expressions for both the internal and the radiated fields, as well as the resonant condition and the ......In this paper, we propose the analytical solution of nano-rod antennas utilizing a cylindrical harmonics expansion. By treating the metallic nano-rods as plasmonic cavities, we derive closed-form expressions for both the internal and the radiated fields, as well as the resonant condition...... and the radiation efficiency. With our theoretical model, we show that besides the plasmonic resonances, efficient radiation takes advantage of (a) rendering a large value of the rods' radius and (b) a central-fed profile, through which the radiation efficiency can reach up to 70% and even higher in a wide...... frequency band. Our theoretical expressions and conclusions are general and pave the way for engineering and further optimization of optical antenna systems and their radiation patterns....

Structural Foaming at the Nano-, Micro-, and Macro-Scales of Continuous Carbon Fiber Reinforced Polymer Matrix Composites

Science.gov (United States)

2012-10-29

structural porosity at MNM scales could be introduced into the matrix, the carbon fiber reinforcement, and during prepreg lamination processing, without...areas, including fibers. Furthermore, investigate prepreg thickness and resin content effects on the thermomechanical performance of laminated ...Accomplishment 4) 5 Develop constitutive models for nano- foamed and micro- foamed PMC systems from single ply prepreg to multilayer laminated

Nano-tribology and materials in MEMS

CERN Document Server

Satyanarayana, N; Lim, Seh

2013-01-01

This book brings together recent developments in the areas of MEMS tribology, novel lubricants and coatings for nanotechnological applications, biomimetics in tribology and fundamentals of micro/nano-tribology. Tribology plays important roles in the functioning and durability of machines at small length scales because of the problems associated with strong surface adhesion, friction, wear etc. Recently, a number of studies have been conducted to understand tribological phenomena at nano/micro scales and many new tribological solutions for MEMS have been proposed.

Applying Nano technology to Human Health: Revolution in Biomedical Sciences

International Nuclear Information System (INIS)

Shrivastava, S.; Dash, D.

2009-01-01

Recent research on bio systems at the nano scale has created one of the most dynamic science and technology domains at the confluence of physical sciences, molecular engineering, biology, biotechnology, and medicine. This domain includes better understanding of living and thinking systems, revolutionary biotechnology processes, synthesis of new drugs and their targeted delivery, regenerative medicine, necrophorum engineering, and developing a sustainable environment. Nano bio systems research is a priority in many countries and its relevance within nano technology is expected to increase in the future. The realisation that the nano scale has certain properties needed to solve important medical challenges and cater to unmet medical needs is driving nano medical research. The present review explores the significance of nano science and latest nano technologies for human health. Addressing the associated opportunities, the review also suggests how to manage far-reaching developments in these areas

DNA electronic circular dichroism on the inter-base pair scale

DEFF Research Database (Denmark)

Di Meo, Florent; Nørby, Morten Steen; Rubio-Magnieto, Jenifer

2015-01-01

A successful elucidation of the near-ultraviolet electronic circular dichroism spectrum of a short double-stranded DNA is reported. Time-dependent density functional theory methods are shown to accurately predict spectra and assign bands on the microscopic base-pair scale, a finding that opens...... the field for using circular dichroism spectroscopy as a sensitive nanoscale probe of DNA to reveal its complex interactions with the environment. (Chemical Equation Presented)....

Biofunctionalization of scaffold material with nano-scaled diamond particles physisorbed with angiogenic factors enhances vessel growth after implantation.

Science.gov (United States)

Schimke, Magdalena M; Stigler, Robert; Wu, Xujun; Waag, Thilo; Buschmann, Peter; Kern, Johann; Untergasser, Gerold; Rasse, Michael; Steinmüller-Nethl, Doris; Krueger, Anke; Lepperdinger, Günter

2016-04-01

Biofunctionalized scaffold facilitates complete healing of large defects. Biological constraints are induction and ingrowth of vessels. Angiogenic growth factors such as vascular endothelial growth factor or angiopoietin-1 can be bound to nano-scaled diamond particles. Corresponding bioactivities need to be examined after biofunctionalization. We therefore determined the physisorptive capacity of distinctly manufactured, differently sized nDP and the corresponding activities of bound factors. The properties of biofunctionalized nDPs were investigated on cultivated human mesenchymal stem cells and on the developing chicken embryo chorio-allantoic membrane. Eventually porous bone substitution material was coated with nDP to generate an interface that allows biofactor physisorption. Angiopoietin-1 was applied shortly before scaffold implantation into an osseous defect in sheep calvaria. Biofunctionalized scaffolds exhibited significantly increased rates of angiogenesis already one month after implantation. Conclusively, nDP can be used to ease functionalization of synthetic biomaterials. With the advances in nanotechnology, many nano-sized materials have been used in the biomedical field. This is also true for nano-diamond particles (nDP). In this article, the authors investigated the physical properties of functionalized nano-diamond particles in both in-vitro and in-vivo settings. The positive findings would help improve understanding of these nanomaterials in regenerative medicine. Copyright © 2015 Elsevier Inc. All rights reserved.

Field limit and nano-scale surface topography of superconducting radio-frequency cavity made of extreme type II superconductor

Science.gov (United States)

Kubo, Takayuki

2015-06-01

The field limit of a superconducting radio-frequency cavity made of a type II superconductor with a large Ginzburg-Landau parameter is studied, taking the effects of nano-scale surface topography into account. If the surface is ideally flat, the field limit is imposed by the superheating field. On the surface of cavity, however, nano-defects almost continuously distribute and suppress the superheating field everywhere. The field limit is imposed by an effective superheating field given by the product of the superheating field for an ideal flat surface and a suppression factor that contains the effects of nano-defects. A nano-defect is modeled by a triangular groove with a depth smaller than the penetration depth. An analytical formula for the suppression factor of bulk and multilayer superconductors is derived in the framework of the London theory. As an immediate application, the suppression factor of the dirty Nb processed by electropolishing is evaluated by using results of surface topographic study. The estimated field limit is consistent with the present record field of nitrogen-doped Nb cavities. Suppression factors of surfaces of other bulk and multilayer superconductors, and those after various surface processing technologies, can also be evaluated by using the formula.

Direct large-scale synthesis of perovskite barium strontium titanate nano-particles from solutions

International Nuclear Information System (INIS)

Qi Jianquan; Wang Yu; Wan Pingchen; Long Tuli; Chan, Helen Lai Wah

2005-01-01

This paper reports a wet chemical synthesis technique for large-scale fabrication of perovskite barium strontium titanate nano-particles near room temperature and under ambient pressure. The process employs titanium alkoxide and alkali earth hydroxides as starting materials and involves very simple operation steps. Particle size and crystallinity of the particles are controllable by changing the processing parameters. Observations by X-ray diffraction, scanning electron microscopy and transmission electron microscopy TEM indicate that the particles are well-crystallized, chemically stoichiometric and ∼50nm in diameter. The nanoparticles can be sintered into ceramics at 1150 deg. C and show typical ferroelectric hysteresis loops

Two-step preparation of nano-scaled magnetic chitosan particles using Triton X-100 reversed-phase water-in-oil microemulsion system

International Nuclear Information System (INIS)

Zhou, Zhengkun; Jiang, Feihong; Lee, Tung-Ching; Yue, Tianli

2013-01-01

Highlights: •A new two-step route for nano-scaled magnetic chitosan particles preparation. •Triton X-100 reversed-phase microemulsion system was used for chitosan coating. •Narrow size distribution of magnetic chitosan nanoparticles was achieved. •Quantitative evaluation of recoverability for the magnetic chitosan nanoparticles. -- Abstract: A new two-step route for the preparation of nano-scaled magnetic chitosan particles has been developed, different from reported one-step in situ preparation and two-step preparation method of reversed-phase suspension, Triton X-100 reversed-phase water-in-oil microemulsion encapsulation method was employed in coating the pre-prepared Fe 3 O 4 nanoparticles with chitosan. The resultant magnetic chitosan particles owned a narrow size distribution ranging from 50 to 92 nm. X-ray diffraction patterns (XRD) indicated that the chitosan coating procedure did not change the spinal structure of Fe 3 O 4 magnetic nanoparticles. The results of Fourier transform infrared (FTIR) analysis and thermogravimetric analysis (TGA) demonstrated that the chitosan was coated on Fe 3 O 4 nanoparticles and its average mass content was ∼50%. The saturated magnetization of the magnetic Fe 3 O 4 /chitosan nanoparticles reached 18.62 emu/g, meanwhile, the nanoparticles showed the characteristics of superparamagnetism. The magnetic chitosan nanoparticles showed a high recoverability of 99.99% in 10 min when pH exceeded 4. The results suggested that the as-prepared magnetic chitosan particles were nano-scaled with a narrow size distribution and a high recoverability

Modeling of the topology of energy deposits created by ionizing radiation on a nano-metric scale in cell nuclei in relation to radiation-induced early events

International Nuclear Information System (INIS)

Dos Santos, Morgane

2013-01-01

Ionizing radiations are known to induce critical damages on biological matter and especially on DNA. Among these damages, DNA double strand breaks (DSB) are considered as key precursor of lethal effects of ionizing radiations. Understand and predict how DNA double and simple strand breaks are created by ionizing radiation and repaired in cell nucleus is nowadays a major challenge in radiobiology research. This work presents the results on the simulation of the DNA double strand breaks produced from the energy deposited by the irradiation at the intracellular level. At the nano-metric scale, the only method to accurately simulate the topological details of energy deposited on the biological matter is the use of Monte Carlo codes. In this work, we used the Geant4 Monte Carlo code and, in particular, the low energy electromagnetic package extensions, referred as Geant4-DNA processes.In order to evaluate DNA radio-induced damages, the first objective of this work consisted in implementing a detailed geometry of the DNA on the Monte Carlo simulations. Two types of cell nuclei, representing a fibroblast and an endothelium, were described in order to evaluate the influence of the DNA density on the topology of the energy deposits contributing to strand breaks. Indeed, the implemented geometry allows the selection of energy transfer points that can lead to strand breaks because they are located on the backbone. Then, these energy transfer points were analysed with a clustering algorithm in order to reveal groups of aggregates and to study their location and complexity. In this work, only the physical interactions of ionizing radiations are simulated. Thus, it is not possible to achieve an absolute number of strand breaks as the creation and transportation of radical species which could lead to indirect DNA damages is not included. Nevertheless, the aim of this work was to evaluate the relative dependence of direct DNA damages with the DNA density, radiation quality, cell

FRET enhancement close to gold nanoparticles positioned in DNA origami constructs.

Science.gov (United States)

Aissaoui, Nesrine; Moth-Poulsen, Kasper; Käll, Mikael; Johansson, Peter; Wilhelmsson, L Marcus; Albinsson, Bo

2017-01-05

Here we investigate the energy transfer rates of a Förster resonance energy transfer (FRET) pair positioned in close proximity to a 5 nm gold nanoparticle (AuNP) on a DNA origami construct. We study the distance dependence of the FRET rate by varying the location of the donor molecule, D, relative to the AuNP while maintaining a fixed location of the acceptor molecule, A. The presence of the AuNP induces an alteration in the spontaneous emission of the donor (including radiative and non-radiative rates) which is strongly dependent on the distance between the donor and AuNP surface. Simultaneously, the energy transfer rates are enhanced at shorter D-A (and D-AuNP) distances. Overall, in addition to the direct influence of the acceptor and AuNP on the donor decay there is also a significant increase in decay rate not explained by the sum of the two interactions. This leads to enhanced energy transfer between donor and acceptor in the presence of a 5 nm AuNP. We also demonstrate that the transfer rate in the three "particle" geometry (D + A + AuNP) depends approximately linearly on the transfer rate in the donor-AuNP system, suggesting the possibility to control FRET process with electric field induced by 5 nm AuNPs close to the donor fluorophore. It is concluded that DNA origami is a very versatile platform for studying interactions between molecules and plasmonic nanoparticles in general and FRET enhancement in particular.

Adhesion and proliferation of OCT-1 osteoblast-like cells on micro- and nano-scale topography structured poly(L-lactide).

Science.gov (United States)

Wan, Yuqing; Wang, Yong; Liu, Zhimin; Qu, Xue; Han, Buxing; Bei, Jianzhong; Wang, Shenguo

2005-07-01

The impact of the surface topography of polylactone-type polymer on cell adhesion was to be concerned because the micro-scale texture of a surface can provide a significant effect on the adhesion behavior of cells on the surface. Especially for the application of tissue engineering scaffold, the pore size could have an influence on cell in-growth and subsequent proliferation. Micro-fabrication technology was used to generate specific topography to investigate the relationship between the cells and surface. In this study the pits-patterned surfaces of polystyrene (PS) film with diameters 2.2 and 0.45 microm were prepared by phase-separation, and the corresponding scale islands-patterned PLLA surface was prepared by a molding technique using the pits-patterned PS as a template. The adhesion and proliferation behavior of OCT-1 osteoblast-like cells morphology on the pits- and islands-patterned surface were characterized by SEM observation, cell attachment efficiency measurement and MTT assay. The results showed that the cell adhesion could be enhanced on PLLA and PS surface with nano-scale and micro-scale roughness compared to the smooth surfaces of the PLLA and PS. The OCT-1 osteoblast-like cells could grow along the surface with two different size islands of PLLA and grow inside the micro-scale pits of the PS. However, the proliferation of cells on the micro- and nano-scale patterned surface has not been enhanced compared with the controlled smooth surface.

A multi scale model for small scale plasticity

International Nuclear Information System (INIS)

Zbib, Hussein M.

2002-01-01

Full text.A framework for investigating size-dependent small-scale plasticity phenomena and related material instabilities at various length scales ranging from the nano-microscale to the mesoscale is presented. The model is based on fundamental physical laws that govern dislocation motion and their interaction with various defects and interfaces. Particularly, a multi-scale model is developed merging two scales, the nano-microscale where plasticity is determined by explicit three-dimensional dislocation dynamics analysis providing the material length-scale, and the continuum scale where energy transport is based on basic continuum mechanics laws. The result is a hybrid simulation model coupling discrete dislocation dynamics with finite element analyses. With this hybrid approach, one can address complex size-dependent problems, including dislocation boundaries, dislocations in heterogeneous structures, dislocation interaction with interfaces and associated shape changes and lattice rotations, as well as deformation in nano-structured materials, localized deformation and shear band

Inspecting close maternal relatedness: Towards better mtDNA population samples in forensic databases.

Science.gov (United States)

Bodner, Martin; Irwin, Jodi A; Coble, Michael D; Parson, Walther

2011-03-01

Reliable data are crucial for all research fields applying mitochondrial DNA (mtDNA) as a genetic marker. Quality control measures have been introduced to ensure the highest standards in sequence data generation, validation and a posteriori inspection. A phylogenetic alignment strategy has been widely accepted as a prerequisite for data comparability and database searches, for forensic applications, for reconstructions of human migrations and for correct interpretation of mtDNA mutations in medical genetics. There is continuing effort to enhance the number of worldwide population samples in order to contribute to a better understanding of human mtDNA variation. This has often lead to the analysis of convenience samples collected for other purposes, which might not meet the quality requirement of random sampling for mtDNA data sets. Here, we introduce an additional quality control means that deals with one aspect of this limitation: by combining autosomal short tandem repeat (STR) marker with mtDNA information, it helps to avoid the bias introduced by related individuals included in the same (small) sample. By STR analysis of individuals sharing their mitochondrial haplotype, pedigree construction and subsequent software-assisted calculation of likelihood ratios based on the allele frequencies found in the population, closely maternally related individuals can be identified and excluded. We also discuss scenarios that allow related individuals in the same set. An ideal population sample would be representative for its population: this new approach represents another contribution towards this goal. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Advanced Nano hybrid Materials: Surface Modification and Applications

International Nuclear Information System (INIS)

Liu, L.H.; Metivier, R.; Wang, Sh.; Wang, Sh.; Hui Wang

2012-01-01

The field of functional nano scale hybrid materials is one of the most promising and rapidly emerging research areas in materials chemistry. Nano scale hybrid materials can be broadly defined as synthetic materials with organic and inorganic components that are linked together by noncovalent bonds (Class I, linked by hydrogen bond, electrostatic force, or van der Waals force) or covalent bonds (Class II) at nanometer scale. The unlimited possible combinations of the distinct properties of inorganic, organic, or even bioactive components in a single material, either in molecular or nano scale dimensions, have attracted considerable attention. This approach provides an opportunity to create a vast number of novel advanced materials with well-controlled structures and multiple functions. The unique properties of advanced hybrid nano materials can be advantageous to many fields, such as optical and electronic materials, biomaterials, catalysis, sensing, coating, and energy storage. In this special issue, the breadth of papers shows that the hybrid materials is attracting attention, because of both growing fundamental interest, and a route to new materials. Two review articles and seven research papers that report new results of hybrid materials should gather widespread interest.

Structures of RNA Polymerase Closed and Intermediate Complexes Reveal Mechanisms of DNA Opening and Transcription Initiation.

Science.gov (United States)

Glyde, Robert; Ye, Fuzhou; Darbari, Vidya Chandran; Zhang, Nan; Buck, Martin; Zhang, Xiaodong

2017-07-06

Gene transcription is carried out by RNA polymerases (RNAPs). For transcription to occur, the closed promoter complex (RPc), where DNA is double stranded, must isomerize into an open promoter complex (RPo), where the DNA is melted out into a transcription bubble and the single-stranded template DNA is delivered to the RNAP active site. Using a bacterial RNAP containing the alternative σ 54 factor and cryoelectron microscopy, we determined structures of RPc and the activator-bound intermediate complex en route to RPo at 3.8 and 5.8 Å. Our structures show how RNAP-σ 54 interacts with promoter DNA to initiate the DNA distortions required for transcription bubble formation, and how the activator interacts with RPc, leading to significant conformational changes in RNAP and σ 54 that promote RPo formation. We propose that DNA melting is an active process initiated in RPc and that the RNAP conformations of intermediates are significantly different from that of RPc and RPo. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

Grain boundary engineering with nano-scale InSb producing high performance InxCeyCo4Sb12+z skutterudite thermoelectrics

Directory of Open Access Journals (Sweden)

Han Li

2017-12-01

Full Text Available Thermoelectric semiconductors based on CoSb3 hold the best promise for recovering industrial or automotive waste heat because of their high efficiency and relatively abundant, lead-free constituent elements. However, higher efficiency is needed before thermoelectrics reach economic viability for widespread use. In this study, n-type InxCeyCo4Sb12+z skutterudites with high thermoelectric performance are produced by combining several phonon scattering mechanisms in a panoscopic synthesis. Using melt spinning followed by spark plasma sintering (MS-SPS, bulk InxCeyCo4Sb12+z alloys are formed with grain boundaries decorated with nano-phase of InSb. The skutterudite matrix has grains on a scale of 100–200 nm and the InSb nano-phase with a typical size of 5–15 nm is evenly dispersed at the grain boundaries of the skutterudite matrix. Coupled with the presence of defects on the Sb sublattice, this multi-scale nanometer structure is exceptionally effective in scattering phonons and, therefore, InxCeyCo4Sb12/InSb nano-composites have very low lattice thermal conductivity and high zT values reaching in excess of 1.5 at 800 K.

Comparative Study of Seven Commercial Kits for Human DNA Extraction from Urine Samples Suitable for DNA Biomarker-Based Public Health Studies

Science.gov (United States)

El Bali, Latifa; Diman, Aurélie; Bernard, Alfred; Roosens, Nancy H. C.; De Keersmaecker, Sigrid C. J.

2014-01-01

Human genomic DNA extracted from urine could be an interesting tool for large-scale public health studies involving characterization of genetic variations or DNA biomarkers as a result of the simple and noninvasive collection method. These studies, involving many samples, require a rapid, easy, and standardized extraction protocol. Moreover, for practicability, there is a necessity to collect urine at a moment different from the first void and to store it appropriately until analysis. The present study compared seven commercial kits to select the most appropriate urinary human DNA extraction procedure for epidemiological studies. DNA yield has been determined using different quantification methods: two classical, i.e., NanoDrop and PicoGreen, and two species-specific real-time quantitative (q)PCR assays, as DNA extracted from urine contains, besides human, microbial DNA also, which largely contributes to the total DNA yield. In addition, the kits giving a good yield were also tested for the presence of PCR inhibitors. Further comparisons were performed regarding the sampling time and the storage conditions. Finally, as a proof-of-concept, an important gene related to smoking has been genotyped using the developed tools. We could select one well-performing kit for the human DNA extraction from urine suitable for molecular diagnostic real-time qPCR-based assays targeting genetic variations, applicable to large-scale studies. In addition, successful genotyping was possible using DNA extracted from urine stored at −20°C for several months, and an acceptable yield could also be obtained from urine collected at different moments during the day, which is particularly important for public health studies. PMID:25365790

Comparative study of seven commercial kits for human DNA extraction from urine samples suitable for DNA biomarker-based public health studies.

Science.gov (United States)

El Bali, Latifa; Diman, Aurélie; Bernard, Alfred; Roosens, Nancy H C; De Keersmaecker, Sigrid C J

2014-12-01

Human genomic DNA extracted from urine could be an interesting tool for large-scale public health studies involving characterization of genetic variations or DNA biomarkers as a result of the simple and noninvasive collection method. These studies, involving many samples, require a rapid, easy, and standardized extraction protocol. Moreover, for practicability, there is a necessity to collect urine at a moment different from the first void and to store it appropriately until analysis. The present study compared seven commercial kits to select the most appropriate urinary human DNA extraction procedure for epidemiological studies. DNA yield has been determined using different quantification methods: two classical, i.e., NanoDrop and PicoGreen, and two species-specific real-time quantitative (q)PCR assays, as DNA extracted from urine contains, besides human, microbial DNA also, which largely contributes to the total DNA yield. In addition, the kits giving a good yield were also tested for the presence of PCR inhibitors. Further comparisons were performed regarding the sampling time and the storage conditions. Finally, as a proof-of-concept, an important gene related to smoking has been genotyped using the developed tools. We could select one well-performing kit for the human DNA extraction from urine suitable for molecular diagnostic real-time qPCR-based assays targeting genetic variations, applicable to large-scale studies. In addition, successful genotyping was possible using DNA extracted from urine stored at -20°C for several months, and an acceptable yield could also be obtained from urine collected at different moments during the day, which is particularly important for public health studies.

Superconducting nano-striplines as quantum detectors

International Nuclear Information System (INIS)

Casaburi, A.; Ejrnaes, M.; Mattioli, F.; Gaggero, A.; Leoni, R.; Martucciello, N.; Pagano, S.; Ohkubo, M.; Cristiano, R.

2011-01-01

The recent progress in the nanofabrication of superconducting films opens the road toward detectors with highly improved performances. This is the case for superconducting nano-striplines where the thickness and the width are pushed down to the extreme limits to realize detectors with unprecedented sensitivity and ultra fast response time. In this way quantum detectors for single photons at telecommunication wavelengths and for macromolecules such as proteins can be realized. As is often the case in applied nanotechnology, it is a challenge to make devices with the necessary macroscopic dimensions that are needed to interface present technologies, while maintaining the performance improvements. For nano-stripline detectors, both the fast temporal response and the device sensitivity is generally degraded when the area is increased. Here, we present how such detectors can be scaled up to macroscopic dimensions without losing the performance of the nano-structured active elements by using an innovative configuration. In order to realize ultrathin superconducting film the nano-layer is growth with a careful setup of the deposition technique which guarantees high quality and thickness uniformity at the nano-scale size. The active nano-strips are defined with the state-of-the-art electron beam nanolithography to achieve a highly uniform linewidth. We present working detectors based on nano-strips with thicknesses 9–40 nm and widths of 100–1000 nm which exhibit unprecedented speed and area coverage (40 × 40 μm 2 for single photon detectors and 1 × 1 mm 2 for single molecule detectors) based on niobium nitride thus enabling practical use of this nanotechnology.

Bulk velocity extraction for nano-scale Newtonian flows

Energy Technology Data Exchange (ETDEWEB)

Zhang, Wenfei, E-mail: zwenfei@gmail.com [Key Laboratory of Mechanical Reliability for Heavy Equipments and Large Structures of Hebei Province, Yanshan University, Qinhuangdao 066004 (China); Sun, Hongyu [Key Laboratory of Mechanical Reliability for Heavy Equipments and Large Structures of Hebei Province, Yanshan University, Qinhuangdao 066004 (China)

2012-04-16

The conventional velocity extraction algorithm in MDS method has difficulty to determine the small flow velocity. This study proposes a new method to calculate the bulk velocity in nano-flows. Based on the Newton's law of viscosity, according to the calculated viscosities and shear stresses, the flow velocity can be obtained by numerical integration. This new method can overcome the difficulty existed in the conventional MDS method and improve the stability of the computational process. Numerical results show that this method is effective for the extraction of bulk velocity, no matter the bulk velocity is large or small. -- Highlights: ► Proposed a new method to calculate the bulk velocity in nano-flows. ► It is effective for the extraction of small bulk velocity. ► The accuracy, convergence and stability of the new method is good.

Bulk velocity extraction for nano-scale Newtonian flows

International Nuclear Information System (INIS)

Zhang, Wenfei; Sun, Hongyu

2012-01-01

The conventional velocity extraction algorithm in MDS method has difficulty to determine the small flow velocity. This study proposes a new method to calculate the bulk velocity in nano-flows. Based on the Newton's law of viscosity, according to the calculated viscosities and shear stresses, the flow velocity can be obtained by numerical integration. This new method can overcome the difficulty existed in the conventional MDS method and improve the stability of the computational process. Numerical results show that this method is effective for the extraction of bulk velocity, no matter the bulk velocity is large or small. -- Highlights: ► Proposed a new method to calculate the bulk velocity in nano-flows. ► It is effective for the extraction of small bulk velocity. ► The accuracy, convergence and stability of the new method is good.

DNA adsorption characteristics of hollow spherule allophane nano-particles

International Nuclear Information System (INIS)

Matsuura, Yoko; Iyoda, Fumitoshi; Arakawa, Shuichi; John, Baiju; Okamoto, Masami; Hayashi, Hidetomo

2013-01-01

To understand the propensity of natural allophane to adsorb the DNA molecules, the adsorption characteristics were assessed against natural allophane (AK70), using single-stranded DNA (ss-DNA) and adenosine 5′-monophosphate (5′-AMP) as a reference molecule. The adsorption capacity of ss-DNA on AK70 exhibited one order of magnitude lower value as compared with that of 5′-AMP. The adsorption capacity of ss-DNA decreased with increasing pH due to the interaction generated between phosphate groups of ss-DNA and functional Al–OH groups on the wall perforations through deprotonating, associated with higher energy barrier for the adsorption of ss-DNA. The adsorption morphologies consisting of the individual ss-DNA with mono-layer coverage of the clustered allophane particle were observed successfully through transmission electron microscopy analysis. - Highlights: • The interaction between phosphate groups of ss-DNA and Al–OH groups • Higher energy barrier for the adsorption of ss-DNA • The individual ss-DNA with mono-layer coverage of the allophane clustered particle

Scaling for quantum tunneling current in nano- and subnano-scale plasmonic junctions.

Science.gov (United States)

Zhang, Peng

2015-05-19

When two conductors are separated by a sufficiently thin insulator, electrical current can flow between them by quantum tunneling. This paper presents a self-consistent model of tunneling current in a nano- and subnano-meter metal-insulator-metal plasmonic junction, by including the effects of space charge and exchange correlation potential. It is found that the J-V curve of the junction may be divided into three regimes: direct tunneling, field emission, and space-charge-limited regime. In general, the space charge inside the insulator reduces current transfer across the junction, whereas the exchange-correlation potential promotes current transfer. It is shown that these effects may modify the current density by orders of magnitude from the widely used Simmons' formula, which is only accurate for a limited parameter space (insulator thickness > 1 nm and barrier height > 3 eV) in the direct tunneling regime. The proposed self-consistent model may provide a more accurate evaluation of the tunneling current in the other regimes. The effects of anode emission and material properties (i.e. work function of the electrodes, electron affinity and permittivity of the insulator) are examined in detail in various regimes. Our simple model and the general scaling for tunneling current may provide insights to new regimes of quantum plasmonics.

Two-step preparation of nano-scaled magnetic chitosan particles using Triton X-100 reversed-phase water-in-oil microemulsion system

Energy Technology Data Exchange (ETDEWEB)

Zhou, Zhengkun; Jiang, Feihong [College of Food Science and Engineering, Northwest A and F University, Yangling, Shaanxi 712100 (China); Lee, Tung-Ching, E-mail: lee@aesop.rutgers.edu [Department of Food Science, Rutgers, the State University of New Jersey, 65 Dudley Road, New Brunswick, NJ 08901 (United States); Yue, Tianli, E-mail: yuetl305@nwsuaf.edu.cn [College of Food Science and Engineering, Northwest A and F University, Yangling, Shaanxi 712100 (China)

2013-12-25

Highlights: •A new two-step route for nano-scaled magnetic chitosan particles preparation. •Triton X-100 reversed-phase microemulsion system was used for chitosan coating. •Narrow size distribution of magnetic chitosan nanoparticles was achieved. •Quantitative evaluation of recoverability for the magnetic chitosan nanoparticles. -- Abstract: A new two-step route for the preparation of nano-scaled magnetic chitosan particles has been developed, different from reported one-step in situ preparation and two-step preparation method of reversed-phase suspension, Triton X-100 reversed-phase water-in-oil microemulsion encapsulation method was employed in coating the pre-prepared Fe{sub 3}O{sub 4} nanoparticles with chitosan. The resultant magnetic chitosan particles owned a narrow size distribution ranging from 50 to 92 nm. X-ray diffraction patterns (XRD) indicated that the chitosan coating procedure did not change the spinal structure of Fe{sub 3}O{sub 4} magnetic nanoparticles. The results of Fourier transform infrared (FTIR) analysis and thermogravimetric analysis (TGA) demonstrated that the chitosan was coated on Fe{sub 3}O{sub 4} nanoparticles and its average mass content was ∼50%. The saturated magnetization of the magnetic Fe{sub 3}O{sub 4}/chitosan nanoparticles reached 18.62 emu/g, meanwhile, the nanoparticles showed the characteristics of superparamagnetism. The magnetic chitosan nanoparticles showed a high recoverability of 99.99% in 10 min when pH exceeded 4. The results suggested that the as-prepared magnetic chitosan particles were nano-scaled with a narrow size distribution and a high recoverability.

Nano-scaling law: geometric foundation of thiolated gold nanomolecules.

Science.gov (United States)

Dass, Amala

2012-04-07

Thiolated gold nanomolecules show a power correlation between the number of gold atoms and the thiolate ligands with a 2/3 scaling similar to Platonic and Archimedean solids. Nanomolecule stability is influenced by a universal geometric factor that is foundational to its stability through the Euclidean surface rule, in addition to the electronic shell closing factor and staple motif requirements. This journal is © The Royal Society of Chemistry 2012

Nano materials for Medical and Dental Applications

International Nuclear Information System (INIS)

Yub Kwon, T.; Oh, D.S.; Narayanan, R.

2015-01-01

Welcome to this special issue. Nano science and nano technology concepts are applicable across all fields of science and a more widespread application of nano materials and nano technologies is imminent or already occurring in many areas, including health care. Today is scientists take those cutting-edge technologies and concepts and apply them to medicine and dentistry. They are finding a wide variety of ways to make medical and dental materials at the nano scale to take advantage of their enhanced physical and biological properties.The purpose of this special issue is to publish high-quality research papers as well as review articles addressing recent advances in the field of nano materials for medical and dental applications. A particular interest is given to papers exploring or discussing nano materials and nano technologies related to delivery system, bonding substitutes, and surface modification techniques applicable in these areas. For this special issue, several investigators were invited to contribute original research findings that can stimulate continuing efforts to understand the cutting-edge applications of nano materials in medicine and dentistry.

Fabrication of micro- and nano-structured materials using mask-less processes

International Nuclear Information System (INIS)

Roy, Sudipta

2007-01-01

Micro- and nano-scale devices are used in electronics, micro-electro- mechanical, bio-analytical and medical components. An essential step for the fabrication of such small scale devices is photolithography. Photolithography requires a master mask to transfer micrometre or sub-micrometre scale patterns onto a substrate. The requirement of a physical, rigid mask can impede progress in applications which require rapid prototyping, flexible substrates, multiple alignment and 3D fabrication. Alternative technologies, which do not require the use of a physical mask, are suitable for these applications. In this paper mask-less methods of micro- and nano-scale fabrication have been discussed. The most common technique, which is the laser direct imaging (LDI), technique has been applied to fabricate micrometre scale structures on printed circuit boards, glass and epoxy. LDI can be combined with chemical methods to deposit metals, inorganic materials as well as some organic entities at the micrometre scale. Inkjet technology can be used to fabricate micrometre patterns of etch resists, organic transistors as well as arrays for bioanalysis. Electrohydrodynamic atomisation is used to fabricate micrometre scale ceramic features. Electrochemical methodologies offer a variety of technical solutions for micro- and nano-fabrication owing to the fact that electron charge transfer can be constrained to a solid-liquid interface. Electrochemical printing is an adaptation of inkjet printing which can be used for rapid prototyping of metallic circuits. Micro-machining using nano-second voltage pulses have been used to fabricate high precision features on metals and semiconductors. Optimisation of reactor, electrochemistry and fluid flow (EnFACE) has also been employed to transfer micrometre scale patterns on a copper substrate. Nano-scale features have been fabricated by using specialised tools such as scanning tunnelling microscopy, atomic force microscopy and focused ion beam. The

Fundamental Issues of Nano-fluid Behavior

International Nuclear Information System (INIS)

Williams, Wesley C.

2006-01-01

This paper will elucidate some of the behaviors of nano-fluids other than the abnormal conductivity enhancement, which are of importance to the experimental and engineering use of nano-fluids. Nano-fluid is the common name of any sol colloid involving nano-scale (less than 100 nm) sized particles dispersed within a base fluid. It has been shown previously that the dispersion of nano-particulate metallic oxides into water can increase thermal conductivity up to 30-40% over that of the base fluid and anomalously more than the mere weighed average of the colloid. There is a great potential for the use of nano-fluids as a way to enhance fluid/thermal energy transfer systems. Due to the recentness of nano-fluid science, there are still many issues which have not been fully investigated. This paper should act as a primer for the basic understanding of nano-fluid behavior. Particle size and colloid stability are of key importance to the functionality of nano-fluids. The pH and concentration/loading of nano-fluids can alter the size of the nano-particles and also the stability of the fluids. It will be shown through experiment and colloid theory the importance of these parameters. Furthermore, most of the existing literature uses volume percentage as the measure of particle loading, which can often be misleading. There will be discussion of this and other misleading ideas in nano-fluid science. (author)

Intranasal delivery of cationic PLGA nano/microparticles-loaded FMDV DNA vaccine encoding IL-6 elicited protective immunity against FMDV challenge.

Directory of Open Access Journals (Sweden)

Gang Wang

Full Text Available Mucosal vaccination has been demonstrated to be an effective means of eliciting protective immunity against aerosol infections of foot and mouth disease virus (FMDV and various approaches have been used to improve mucosal response to this pathogen. In this study, cationic PLGA (poly(lactide-co-glycolide nano/microparticles were used as an intranasal delivery vehicle as a means administering FMDV DNA vaccine encoding the FMDV capsid protein and the bovine IL-6 gene as a means of enhancing mucosal and systemic immune responses in animals. Three eukaryotic expression plasmids with or without bovine IL-6 gene (pc-P12A3C, pc-IL2AP12A3C and pc-P12AIL3C were generated. The two latter plasmids were designed with the IL-6 gene located either before or between the P12A and 3C genes, respectively, as a means of determining if the location of the IL-6 gene affected capsid assembly and the subsequent immune response. Guinea pigs and rats were intranasally vaccinated with the respective chitosan-coated PLGA nano/microparticles-loaded FMDV DNA vaccine formulations. Animals immunized with pc-P12AIL3C (followed by animals vaccinated with pc-P12A3C and pc-IL2AP12A3C developed the highest levels of antigen-specific serum IgG and IgA antibody responses and the highest levels of sIgA (secretory IgA present in mucosal tissues. However, the highest levels of neutralizing antibodies were generated in pc-IL2AP12A3C-immunized animals (followed by pc-P12AIL3C- and then in pc-P12A3C-immunized animals. pc-IL2AP12A3C-immunized animals also developed stronger cell mediated immune responses (followed by pc-P12AIL3C- and pc-P12A3C-immunized animals as evidenced by antigen-specific T-cell proliferation and expression levels of IFN-γ by both CD4+ and CD8+ splenic T cells. The percentage of animals protected against FMDV challenge following immunizations with pc-IL2AP12A3C, pc-P12AIL3C or pc-P12A3C were 3/5, 1/5 and 0/5, respectively. These data suggested that intranasal delivery

Mathematical and numerical modelling of fluids at Nano-metric scales

International Nuclear Information System (INIS)

Joubaud, R.

2012-01-01

This work presents some contributions to the mathematical and numerical modelling of fluids at Nano-metric scales. We are interested in two levels of modelling. The first level consists in an atomic description. We consider the problem of computing the shear viscosity of a fluid from a microscopic description. More precisely, we study the mathematical properties of the nonequilibrium Langevin dynamics allowing to compute the shear viscosity. The second level of description is a continuous description, and we consider a class of continuous models for equilibrium electrolytes, which incorporate on the one hand a confinement by charged solid objects and on the other hand non-ideality effects stemming from electrostatic correlations and steric exclusion phenomena due to the excluded volume effects. First, we perform the mathematical analysis of the case where the free energy is a convex function (mild non-ideality). Second, we consider numerically the case where the free energy is a non convex function (strong non-ideality) leading in particular to phase separation. (author)

Preparation of biomimetic nano-structured films with multi-scale roughness

Science.gov (United States)

Shelemin, A.; Nikitin, D.; Choukourov, A.; Kylián, O.; Kousal, J.; Khalakhan, I.; Melnichuk, I.; Slavínská, D.; Biederman, H.

2016-06-01

Biomimetic nano-structured films are valuable materials in various applications. In this study we introduce a fully vacuum-based approach for fabrication of such films. The method combines deposition of nanoparticles (NPs) by gas aggregation source and deposition of overcoat thin film that fixes the nanoparticles on a surface. This leads to the formation of nanorough surfaces which, depending on the chemical nature of the overcoat, may range from superhydrophilic to superhydrophobic. In addition, it is shown that by proper adjustment of the amount of NPs it is possible to tailor adhesive force on superhydrophobic surfaces. Finally, the possibility to produce NPs in a wide range of their size (45-240 nm in this study) makes it possible to produce surfaces not only with single scale roughness, but also with bi-modal or even multi-modal character. Such surfaces were found to be superhydrophobic with negligible water contact angle hysteresis and hence truly slippery.

Preparation of biomimetic nano-structured films with multi-scale roughness

International Nuclear Information System (INIS)

Shelemin, A; Nikitin, D; Choukourov, A; Kylián, O; Kousal, J; Khalakhan, I; Melnichuk, I; Slavínská, D; Biederman, H

2016-01-01

Biomimetic nano-structured films are valuable materials in various applications. In this study we introduce a fully vacuum-based approach for fabrication of such films. The method combines deposition of nanoparticles (NPs) by gas aggregation source and deposition of overcoat thin film that fixes the nanoparticles on a surface. This leads to the formation of nanorough surfaces which, depending on the chemical nature of the overcoat, may range from superhydrophilic to superhydrophobic. In addition, it is shown that by proper adjustment of the amount of NPs it is possible to tailor adhesive force on superhydrophobic surfaces. Finally, the possibility to produce NPs in a wide range of their size (45–240 nm in this study) makes it possible to produce surfaces not only with single scale roughness, but also with bi-modal or even multi-modal character. Such surfaces were found to be superhydrophobic with negligible water contact angle hysteresis and hence truly slippery. (paper)

Comparison of DNA damage in human lymphocytes from healthy individuals and asthma, COPD and lung cancer patients treated in vitro / ex vivo with the bulk nano forms of aspirin and ibuprofen

Directory of Open Access Journals (Sweden)

Mojgan Najafzadeh

2015-05-01

Full Text Available Non-steroidal anti-inflammatory drugs (NSAIDs inhibit COX enzyme activity, a significant mechanism of action of NSAIDs. Inflammation is associated with increasing cancer incidence. Recent pre-clinical and clinical studies have shown that NSAID treatment could cause an anti-tumour effect in cancers. Such studies are lengthy and expensive. The present study, however, examined DNA damage in the Comet and micronucleus assays in peripheral blood lymphocytes of patients with respiratory diseases and healthy individuals using the nanoparticle (NP and bulk versions of the NSAIDs, aspirin and ibuprofen. Lymphocytes are suitable surrogate cells for cancers and other disease states. DNA damage decreased in lymphocytes from healthy individuals, asthma, COPD and lung cancer patient groups after treatment with aspirin nano-suspension (ASP N and ibuprofen nano-suspension (IBU N compared to their bulk version (micro-suspension in both assays. However, when ASP N was compared to untreated lymphocytes in all groups in the Comet assay, DNA damage significantly decreased in all groups, except the asthma group. When IBU N was compared to untreated lymphocytes, in healthy individuals and the lung cancer group, DNA damage decreased, but increased in asthma and COPD groups. Similarly, micronuclei (MNi increased after ASP N and IBU N in the healthy individual and lung cancer groups, and decreased in asthma and COPD groups. Also shows that whilst there are basic similarities with different genetic endpoints in terms of nano and bulk forms, but highlights some differences between the disease states examined. Furthermore, lymphocyte responses after IBU N and ibuprofen bulk were investigated by patch-clamp experiments demonstrating that IBU N inhibited ion channel activity by 20%. This molecular epidemiology approach mirrors pre-clinical and clinical findings, and provides new information using nanoparticles.

Nano-electromembrane extraction

DEFF Research Database (Denmark)

Payán, María D Ramos; Li, Bin; Petersen, Nickolaj J.

2013-01-01

as extraction selectivity. Compared with conventional EME, the acceptor phase volume in nano-EME was down-scaled by a factor of more than 1000. This resulted in a very high enrichment capacity. With loperamide as an example, an enrichment factor exceeding 500 was obtained in only 5 min of extraction...... electrophoresis (CE). In that way the sample preparation performed by nano-EME was coupled directly with a CE separation. Separation performance of 42,000-193,000 theoretical plates could easily be obtained by this direct sample preparation and injection technique that both provided enrichment as well...

Gel nano-particulates against radioactivity

International Nuclear Information System (INIS)

Deroin, Ph.

2004-01-01

The Argonne research center (USA) has developed a 'super-gel' compound, a polymer close to those used in baby's diapers, which can reach a 90% efficiency in the radioactive decontamination of porous materials, like bricks or concrete. The contaminated materials are sprayed with a mixture of polymer gel and wetting agent with nano-particulates in suspension. Under the action of the wetting agent, radioactivity migrates from the pores to the gel and is trapped by the nano-particulates. The drying and recycling of the gel allows to reduce the volume of radioactive wastes. Short paper. (J.S.)

A new nano-biophotonics toolbox

DEFF Research Database (Denmark)

Glückstad, Jesper; Bañas, Andrew Rafael; Palima, Darwin

The science fiction inspired shrinking of macro-scale robotic manipulation and handling down to the micro- and nano-scale regime open new doors for exploiting the forces and torques of light for micro- and nanobiologic probing, actuation and control. A generic approach for optimizing light...

Transgene and immune gene expression following intramuscular injection of Atlantic salmon (Salmo salar L.) with DNA-releasing PLGA nano- and microparticles.

Science.gov (United States)

Hølvold, Linn Benjaminsen; Fredriksen, Børge N; Bøgwald, Jarl; Dalmo, Roy A

2013-09-01

The use of poly-(D,L-lactic-co-glycolic) acid (PLGA) particles as carriers for DNA delivery has received considerable attention in mammalian studies. DNA vaccination of fish has been shown to elicit durable transgene expression, but no reports exist on intramuscular administration of PLGA-encapsulated plasmid DNA (pDNA). We injected Atlantic salmon (Salmo salar L.) intramuscularly with a plasmid vector containing a luciferase (Photinus pyralis) reporter gene as a) naked pDNA, b) encapsulated into PLGA nano- (~320 nm) (NP) or microparticles (~4 μm) (MP), c) in an oil-based formulation, or with empty particles of both sizes. The ability of the different pDNA-treatments to induce transgene expression was analyzed through a 70-day experimental period. Anatomical distribution patterns and depot effects were determined by tracking isotope labeled pDNA. Muscle, head kidney and spleen from all treatment groups were analyzed for proinflammatory cytokines (TNF-α, IL-1β), antiviral genes (IFN-α, Mx) and cytotoxic T-cell markers (CD8, Eomes) at mRNA transcription levels at days 1, 2, 4 and 7. Histopathological examinations were performed on injection site samples from days 2, 7 and 30. Injection of either naked pDNA or the oil-formulation was superior to particle treatments for inducing transgene expression at early time-points. Empty particles of both sizes were able to induce proinflammatory immune responses as well as degenerative and inflammatory pathology at the injection site. Microparticles demonstrated injection site depots and an inflammatory pathology comparable to the oil-based formulation. In comparison, the distribution of NP-encapsulated pDNA resembled that of naked pDNA, although encapsulation into NPs significantly elevated the expression of antiviral genes in all tissues. Together the results indicate that while naked pDNA is most efficient for inducing transgene expression, the encapsulation of pDNA into NPs up-regulates antiviral responses that could be

High-strength wrought magnesium alloy with dense nano-scale spherical precipitate

Institute of Scientific and Technical Information of China (English)

YU WenBin; CHEN ZhiQian; CHENG NanPu; GAN BingTai; HE Hong; LI XueLian; HU JinZhu

2007-01-01

This paper reported the influences of Yb addition on the precipitate and mechanical properties of wrought magnesium alloy ZK60. The ingots of ZK60-1.78Yb (wt%,0.26 at%) alloys were cast using permanent mould and extruded at 370℃. By means of TEM and HRTEM,it was observed that Yb affected the precipitate and precipitation of ZK60-1.78Yb alloys significantly. Dynamic precipitation occurred in the as-extruded alloy and spherical nano-scale precipitate with high density and homogeneity exhibited in the aged alloys. The precipitate particles were about 5-20 nm in diameter,10-30 nm in average space length. The tensile test results showed that the ZK60-1.78Yb alloy had excellent precipitation strengthening response with the maximum tensile strength 417.5 MPa at ambient temperature.

Towards security in nano-communication : Challenges and opportunities

NARCIS (Netherlands)

Dressler, Falko; Kargl, Frank

Incredible improvements in the field of nano-technologies have enabled nano-scale machines that promise new solutions for several applications in biomedical, industry and military fields. Some of these applications require or might exploit the potential advantages of communication and hence

One-step large-scale deposition of salt-free DNA origami nanostructures

Science.gov (United States)

Linko, Veikko; Shen, Boxuan; Tapio, Kosti; Toppari, J. Jussi; Kostiainen, Mauri A.; Tuukkanen, Sampo

2015-01-01

DNA origami nanostructures have tremendous potential to serve as versatile platforms in self-assembly -based nanofabrication and in highly parallel nanoscale patterning. However, uniform deposition and reliable anchoring of DNA nanostructures often requires specific conditions, such as pre-treatment of the chosen substrate or a fine-tuned salt concentration for the deposition buffer. In addition, currently available deposition techniques are suitable merely for small scales. In this article, we exploit a spray-coating technique in order to resolve the aforementioned issues in the deposition of different 2D and 3D DNA origami nanostructures. We show that purified DNA origamis can be controllably deposited on silicon and glass substrates by the proposed method. The results are verified using either atomic force microscopy or fluorescence microscopy depending on the shape of the DNA origami. DNA origamis are successfully deposited onto untreated substrates with surface coverage of about 4 objects/mm2. Further, the DNA nanostructures maintain their shape even if the salt residues are removed from the DNA origami fabrication buffer after the folding procedure. We believe that the presented one-step spray-coating method will find use in various fields of material sciences, especially in the development of DNA biochips and in the fabrication of metamaterials and plasmonic devices through DNA metallisation. PMID:26492833

Quantitative anomalous small-angle X-ray scattering - The determination of chemical concentrations in nano-scale phases

International Nuclear Information System (INIS)

Goerigk, G.; Huber, K.; Mattern, N.; Williamson, D.L.

2012-01-01

In the last years Anomalous Small-Angle X-ray Scattering became a precise quantitative method resolving scattering contributions two or three orders of magnitude smaller compared to the overall small-angle scattering, which are related to the so-called pure-resonant scattering contribution. Additionally to the structural information precise quantitative information about the different constituents of multi-component systems like the fraction of a chemical component implemented into the materials nano-structures are obtained from these scattering contributions. The application of the Gauss elimination algorithm to the vector equation established by ASAXS measurements at three X-ray energies is demonstrated for three examples from chemistry and solid state physics. All examples deal with the quantitative analysis of the Resonant Invariant (RI-analysis). From the integrals of the pure-resonant scattering contribution the chemical concentrations in nano-scaled phases are determined. In one example the correlated analysis of the Resonant Invariant and the Non-resonant Invariant (NI-analysis) is employed. (authors)

Interaction of carbon nano tubes with DNA segments

International Nuclear Information System (INIS)

Peressinotto, Valdirene Sullas Teixeira

2007-01-01

Single- and double-stranded DNA (deoxyribonucleic acid) molecules can strongly bind to single-walled carbon nanotubes (SWNT) via non-covalent interactions. Under certain conditions, the DNA molecule spontaneously self-assembles into a helical wrapping around the tubular structure of the carbon nanotubes to form DNA/SWNT hybrids, which are both stable and soluble in water. This system has recently received extensive attention, since, besides rendering SWNTs dispersible in water as individual tubes, the DNA hybrids are very promising candidates for many applications in nanotechnology and molecular biology. All the possible applications for DNA-SWNT hybrids require, however, a fully understanding of DNA-nanotube wrapping mechanism which is still lacking in the literature. In this context, the aim of this work was to investigate the non-covalent interaction in aqueous medium between SWNTs and synthetic DNA segments having a known nucleotide sequence. Initially, the study was focused on poly d(GT)n sequences (n = 10, 30 and 45) that contain a sequence of alternating guanine and thymine bases and for which the efficiency to disperse and separate carbon nanotubes has already been demonstrated. Besides the size of GT sequences, the effects of ionic strength and pH in the interaction were also investigated. Afterwards, we studied the interaction of SWNT with DNA molecules that contain only a single type of nitrogenous base (DNA homopolymers), which has not been reported in details in the literature. We investigated homopolymers of poly dA 20 , poly dT 20 , poly dC 20 and the duplex poly dA 20 :dT 20 . Most of the study was carried out with small-diameter HiPco SWNTs (with diameters between 0.7 and 1.2 nm). In some studies, SWNTs with diameter around 1.4 nm, synthesized via laser ablation and arc-discharge methods, were also investigated. The arc-discharge nanotubes used in this study were functionalized with carboxylic groups (-COOH) due to their purification using strong

Image analysis of the nano DDS using photon radiation in SPring-8

International Nuclear Information System (INIS)

Noda, Nobuo; Koide, Kazuharu; Nemoto, Tetsuya; Matsuura, Hiroyuki; Makino, Ken-ichi; Nakano, Masahiro; Ju, Dong-Ying; Bian, Pei

2007-01-01

Recently, technology to handle a molecule of nano scale advances, and an applied technology is developed in every area. Development of nano-drug delivery system (DDS) is performed worldwide in the med-tech area. We try the effectiveness of nano-DDS. The dynamic behavior of nano-scale magnet in biomaterials is not well known. Therefore it is necessary we perform direct observation, and to get information of the behavior. Using strong photon beams in Spring-8 facility, we trace the magnets and investigate the leaf or the egg. (author)

Olefin metathesis in nano-sized systems

Directory of Open Access Journals (Sweden)

Denise Méry

2011-01-01

Full Text Available The interplay between olefin metathesis and dendrimers and other nano systems is addressed in this mini review mostly based on the authors’ own contributions over the last decade. Two subjects are presented and discussed: (i The catalysis of olefin metathesis by dendritic nano-catalysts via either covalent attachment (ROMP or, more usefully, dendrimer encapsulation – ring closing metathesis (RCM, cross metathesis (CM, enyne metathesis reactions (EYM – for reactions in water without a co-solvent and (ii construction and functionalization of dendrimers by CM reactions.

Reconstruction of molecular phylogeny of closely related Amorphophallus species of India using plastid DNA marker and fingerprinting approaches.

Science.gov (United States)

Gholave, Avinash R; Pawar, Kiran D; Yadav, Shrirang R; Bapat, Vishwas A; Jadhav, Jyoti P

2017-01-01

Plastid DNA markers sequencing and DNA fingerprinting approaches were used and compared for resolving molecular phylogeny of closely related, previously unexplored Amorphophallus species of India. The utility of individual plastid markers namely rbcL , matK , trnH - psbA , trnLC - trnLD , their combined dataset and two fingerprinting techniques viz. RAPD and ISSR were tested for their efficacy to resolves Amorphophallus species into three sections specific clades namely Rhaphiophallus , Conophallus and Amorphophallus . In the present study, sequences of these four plastid DNA regions as well as RAPD and ISSR profiles of 16 Amorphophallus species together with six varieties of two species were generated and analyzed. Maximum likelihood and Bayesian Inference based construction of phylogenetic trees indicated that among the four plastid DNA regions tested individually and their combined dataset, rbcL was found best suited for resolving closely related Amorphophallus species into section specific clades. When analyzed individually, rbcL exhibited better discrimination ability than matK , trnH - psbA , trnLC - trnLD and combination of all four tested plastid markers. Among two fingerprinting techniques used, the resolution of Amorphophallus species using RAPD was better than ISSR and combination of RAPD +ISSR and in congruence with resolution based on rbcL .

Nano-photonics: past and present

Science.gov (United States)

Szu, Harold

2010-04-01

Nanotech is at the scale of 10-9 meters, located at the mesocopic transition phase, which can take both classical mechanics (CM) and quantum mechanics (QM) descriptions bridging ten orders of magnitude phenomena, between the microscopic world of a single atom at 10-10 meters with the macroscopic world at meters. However, QM principles aid the understanding of any unusual property at the nanotech level. The other major difference between nano-photonics and other forms of optics is that the nano-scale is not very 'hands on'. For the most part, we will not be able to see the components with our naked eyes, but will be required to use some nanotech imaging tools, as follows:

Helicase and Polymerase Move Together Close to the Fork Junction and Copy DNA in One-Nucleotide Steps

Directory of Open Access Journals (Sweden)

Manjula Pandey

2014-03-01

Full Text Available By simultaneously measuring DNA synthesis and dNTP hydrolysis, we show that T7 DNA polymerase and T7 gp4 helicase move in sync during leading-strand synthesis, taking one-nucleotide steps and hydrolyzing one dNTP per base-pair unwound/copied. The cooperative catalysis enables the helicase and polymerase to move at a uniformly fast rate without guanine:cytosine (GC dependency or idling with futile NTP hydrolysis. We show that the helicase and polymerase are located close to the replication fork junction. This architecture enables the polymerase to use its strand-displacement synthesis to increase the unwinding rate, whereas the helicase aids this process by translocating along single-stranded DNA and trapping the unwound bases. Thus, in contrast to the helicase-only unwinding model, our results suggest a model in which the helicase and polymerase are moving in one-nucleotide steps, DNA synthesis drives fork unwinding, and a role of the helicase is to trap the unwound bases and prevent DNA reannealing.

Closed-form solution for static pull-in voltage of electrostatically actuated clamped-clamped micro/nano beams under the effect of fringing field and van der Waals force

Science.gov (United States)

Bhojawala, V. M.; Vakharia, D. P.

2017-12-01

This investigation provides an accurate prediction of static pull-in voltage for clamped-clamped micro/nano beams based on distributed model. The Euler-Bernoulli beam theory is used adapting geometric non-linearity of beam, internal (residual) stress, van der Waals force, distributed electrostatic force and fringing field effects for deriving governing differential equation. The Galerkin discretisation method is used to make reduced-order model of the governing differential equation. A regime plot is presented in the current work for determining the number of modes required in reduced-order model to obtain completely converged pull-in voltage for micro/nano beams. A closed-form relation is developed based on the relationship obtained from curve fitting of pull-in instability plots and subsequent non-linear regression for the proposed relation. The output of regression analysis provides Chi-square (χ 2) tolerance value equals to 1  ×  10-9, adjusted R-square value equals to 0.999 29 and P-value equals to zero, these statistical parameters indicate the convergence of non-linear fit, accuracy of fitted data and significance of the proposed model respectively. The closed-form equation is validated using available data of experimental and numerical results. The relative maximum error of 4.08% in comparison to several available experimental and numerical data proves the reliability of the proposed closed-form equation.

Concentrations of environmental DNA (eDNA) reflect spawning salmon abundance at fine spatial and temporal scales

Science.gov (United States)

Tillotson, Michael D.; Kelly, Ryan P.; Duda, Jeff; Hoy, Marshal S.; Kralj, James; Quinn, Thomas P.

2018-01-01

Developing fast, cost-effective assessments of wild animal abundance is an important goal for many researchers, and environmental DNA (eDNA) holds much promise for this purpose. However, the quantitative relationship between species abundance and the amount of DNA present in the environment is likely to vary substantially among taxa and with ecological context. Here, we report a strong quantitative relationship between eDNA concentration and the abundance of spawning sockeye salmon in a small stream in Alaska, USA, where we took temporally- and spatially-replicated samples during the spawning period. This high-resolution dataset suggests that (1) eDNA concentrations vary significantly day-to-day, and likely within hours, in the context of the dynamic biological event of a salmon spawning season; (2) eDNA, as detected by species-specific quantitative PCR probes, seems to be conserved over short distances (tens of meters) in running water, but degrade quickly over larger scales (ca. 1.5 km); and (3) factors other than the mere presence of live, individual fish — such as location within the stream, live/dead ratio, and water temperature — can affect the eDNA-biomass correlation in space or time. A multivariate model incorporating both biotic and abiotic variables accounted for over 75% of the eDNA variance observed, suggesting that where a system is well-characterized, it may be possible to predict species' abundance from eDNA surveys, although we underscore that species- and system-specific variables are likely to limit the generality of any given quantitative model. Nevertheless, these findings provide an important step toward quantitative applications of eDNA in conservation and management.

Nano-regime Length Scales Extracted from the First Sharp Diffraction Peak in Non-crystalline SiO2 and Related Materials: Device Applications

Directory of Open Access Journals (Sweden)

Phillips James

2010-01-01

Full Text Available Abstract This paper distinguishes between two different scales of medium range order, MRO, in non-crystalline SiO2: (1 the first is ~0.4 to 0.5 nm and is obtained from the position of the first sharp diffraction peak, FSDP, in the X-ray diffraction structure factor, S(Q, and (2 the second is ~1 nm and is calculated from the FSDP full-width-at-half-maximum FWHM. Many-electron calculations yield Si–O third- and O–O fourth-nearest-neighbor bonding distances in the same 0.4–0.5 nm MRO regime. These derive from the availability of empty Si dπ orbitals for back-donation from occupied O pπ orbitals yielding narrow symmetry determined distributions of third neighbor Si–O, and fourth neighbor O–O distances. These are segments of six member rings contributing to connected six-member rings with ~1 nm length scale within the MRO regime. The unique properties of non-crystalline SiO2 are explained by the encapsulation of six-member ring clusters by five- and seven-member rings on average in a compliant hard-soft nano-scaled inhomogeneous network. This network structure minimizes macroscopic strain, reducing intrinsic bonding defects as well as defect precursors. This inhomogeneous CRN is enabling for applications including thermally grown ~1.5 nm SiO2 layers for Si field effect transistor devices to optical components with centimeter dimensions. There are qualitatively similar length scales in nano-crystalline HfO2 and phase separated Hf silicates based on the primitive unit cell, rather than a ring structure. Hf oxide dielectrics have recently been used as replacement dielectrics for a new generation of Si and Si/Ge devices heralding a transition into nano-scale circuits and systems on a Si chip.

A multi-physics modelling framework to describe the behaviour of nano-scale multilayer systems undergoing irradiation damage

International Nuclear Information System (INIS)

Villani, Aurelien

2015-01-01

Radiation damage is known to lead to material failure and thus is of critical importance to lifetime and safety within nuclear reactors. While mechanical behaviour of materials under irradiation has been the subject of numerous studies, the current predictive capabilities of such phenomena appear limited. The clustering of point defects such as vacancies and self interstitial atoms gives rise to creep, void swelling and material embrittlement. Nano-scale metallic multilayer systems have be shown to have the ability to evacuate such point defects, hence delaying the occurrence of critical damage. In addition, they exhibit outstanding mechanical properties. The objective of this work is to develop a thermodynamically consistent continuum framework at the meso and nano-scales, which accounts for the major physical processes encountered in such metallic multilayer systems and is able to predict their microstructural evolution and behavior under irradiation. Mainly three physical phenomena are addressed in the present work: stress-diffusion coupling and diffusion induced creep, the void nucleation and growth in multilayer systems under irradiation, and the interaction of dislocations with the multilayer interfaces. In this framework, the microstructure is explicitly modeled, in order to account accurately for their effects on the system behavior. The diffusion creep strain rate is related to the gradient of the vacancy flux. A Cahn-Hilliard approach is used to model void nucleation and growth, and the diffusion equations for vacancies and self interstitial atoms are complemented to take into account the production of point defects due to irradiation cascades, the mutual recombination of defects and their evacuation through grain boundaries. In metallic multilayers, an interface affected zone is defined, with an additional slip plane to model the interface shearable character, and where dislocations cores are able to spread. The model is then implemented numerically

Genome-scale analysis of aberrant DNA methylation in colorectal cancer

Science.gov (United States)

Hinoue, Toshinori; Weisenberger, Daniel J.; Lange, Christopher P.E.; Shen, Hui; Byun, Hyang-Min; Van Den Berg, David; Malik, Simeen; Pan, Fei; Noushmehr, Houtan; van Dijk, Cornelis M.; Tollenaar, Rob A.E.M.; Laird, Peter W.

2012-01-01

Colorectal cancer (CRC) is a heterogeneous disease in which unique subtypes are characterized by distinct genetic and epigenetic alterations. Here we performed comprehensive genome-scale DNA methylation profiling of 125 colorectal tumors and 29 adjacent normal tissues. We identified four DNA methylation–based subgroups of CRC using model-based cluster analyses. Each subtype shows characteristic genetic and clinical features, indicating that they represent biologically distinct subgroups. A CIMP-high (CIMP-H) subgroup, which exhibits an exceptionally high frequency of cancer-specific DNA hypermethylation, is strongly associated with MLH1 DNA hypermethylation and the BRAFV600E mutation. A CIMP-low (CIMP-L) subgroup is enriched for KRAS mutations and characterized by DNA hypermethylation of a subset of CIMP-H-associated markers rather than a unique group of CpG islands. Non-CIMP tumors are separated into two distinct clusters. One non-CIMP subgroup is distinguished by a significantly higher frequency of TP53 mutations and frequent occurrence in the distal colon, while the tumors that belong to the fourth group exhibit a low frequency of both cancer-specific DNA hypermethylation and gene mutations and are significantly enriched for rectal tumors. Furthermore, we identified 112 genes that were down-regulated more than twofold in CIMP-H tumors together with promoter DNA hypermethylation. These represent ∼7% of genes that acquired promoter DNA methylation in CIMP-H tumors. Intriguingly, 48/112 genes were also transcriptionally down-regulated in non-CIMP subgroups, but this was not attributable to promoter DNA hypermethylation. Together, we identified four distinct DNA methylation subgroups of CRC and provided novel insight regarding the role of CIMP-specific DNA hypermethylation in gene silencing. PMID:21659424

Integrated lithography to prepare periodic arrays of nano-objects

International Nuclear Information System (INIS)

Sipos, Áron; Szalai, Anikó; Csete, Mária

2013-01-01

We present an integrated lithography method to prepare versatile nano-objects with variable shape and nano-scaled substructure, in wavelength-scaled periodic arrays with arbitrary symmetry. The idea is to illuminate colloid sphere monolayers by polarized beams possessing periodic lateral intensity modulations. Finite element method was applied to determine the effects of the wavelength, polarization and angle of incidence of the incoming beam, and to predict the characteristics of nano-objects, which can be fabricated on thin metal layer covered substrates due to the near-field enhancement under silica colloid spheres. The inter-object distance is controlled by varying the relative orientation of the periodic intensity modulation with respect to the silica colloid sphere monolayer. It is shown that illuminating silica colloid sphere monolayers by two interfering beams, linear patterns made of elliptical holes appear in case of linear polarization, while circularly polarized beams result in co-existent rounded objects, as more circular nano-holes and nano-crescents. The size of the nano-objects and their sub-structure is determined by the spheres diameter and by the wavelength. We present various complex plasmonic patterns made of versatile nano-objects that can be uniquely fabricated applying the inherent symmetry breaking possibilities in the integrated lithography method.

Large Scale Plasmonic nanoCones array For Spectroscopy Detection

KAUST Repository

Das, Gobind

2015-09-24

Advanced optical materials or interfaces are gaining attention for diagnostic applications. However, the achievement of large device interface as well as facile surface functionalization largely impairs their wide use. The present work is aimed to address different innovative aspects related to the fabrication of large area 3D plasmonic arrays, their direct and easy functionalization with capture elements and their spectroscopic verifications through enhanced Raman and enhanced fluorescence techniques. In detail we have investigated the effect of Au-based nanoCones array, fabricated by means of direct nanoimprint technique over large area (mm2), on protein capturing and on the enhancement in optical signal. A selective functionalization of gold surfaces was proposed by using a peptide (AuPi3) previously selected by phage display. In this regard, two different sequences, labeled with fluorescein and biotin, were chemisorbed on metallic surfaces. The presence of Au nanoCones array consents an enhancement in electric field on the apex of cone, enabling the detection of molecules. We have witnessed around 12-fold increase in fluorescence intensity and SERS enhancement factor around 1.75 ×105 with respect to the flat gold surface. Furthermore, a sharp decrease in fluorescence lifetime over nanoCones confirms the increase in radiative emission (i.e. an increase in photonics density at the apex of cones).

Large Scale Plasmonic nanoCones array For Spectroscopy Detection

KAUST Repository

Das, Gobind; Battista, Edmondo; Manzo, Gianluigi; Causa, Filippo; Netti, Paolo; Di Fabrizio, Enzo M.

2015-01-01

Advanced optical materials or interfaces are gaining attention for diagnostic applications. However, the achievement of large device interface as well as facile surface functionalization largely impairs their wide use. The present work is aimed to address different innovative aspects related to the fabrication of large area 3D plasmonic arrays, their direct and easy functionalization with capture elements and their spectroscopic verifications through enhanced Raman and enhanced fluorescence techniques. In detail we have investigated the effect of Au-based nanoCones array, fabricated by means of direct nanoimprint technique over large area (mm2), on protein capturing and on the enhancement in optical signal. A selective functionalization of gold surfaces was proposed by using a peptide (AuPi3) previously selected by phage display. In this regard, two different sequences, labeled with fluorescein and biotin, were chemisorbed on metallic surfaces. The presence of Au nanoCones array consents an enhancement in electric field on the apex of cone, enabling the detection of molecules. We have witnessed around 12-fold increase in fluorescence intensity and SERS enhancement factor around 1.75 ×105 with respect to the flat gold surface. Furthermore, a sharp decrease in fluorescence lifetime over nanoCones confirms the increase in radiative emission (i.e. an increase in photonics density at the apex of cones).

Unified nano-mechanics based probabilistic theory of quasibrittle and brittle structures: I. Strength, static crack growth, lifetime and scaling

Science.gov (United States)

Le, Jia-Liang; Bažant, Zdeněk P.; Bazant, Martin Z.

2011-07-01

strength and tests of the power law for the crack growth rate. The theory is shown to match closely numerous test data on strength and static lifetime of ceramics and concrete, and explains why their histograms deviate systematically from the straight line in Weibull scale. Although the present unified theory is built on several previous advances, new contributions are here made to address: (i) a crack in a disordered nano-structure (such as that of hydrated Portland cement), (ii) tail probability of a fiber bundle (or parallel coupling) model with softening elements, (iii) convergence of this model to the Gaussian distribution, (iv) the stress-life curve under constant load, and (v) a detailed random walk analysis of crack front jumps in an atomic lattice. The nonlocal behavior is captured in the present theory through the finiteness of the number of links in the weakest-link model, which explains why the mean size effect coincides with that of the previously formulated nonlocal Weibull theory. Brittle structures correspond to the large-size limit of the present theory. An important practical conclusion is that the safety factors for strength and tolerable minimum lifetime for large quasibrittle structures (e.g., concrete structures and composite airframes or ship hulls, as well as various micro-devices) should be calculated as a function of structure size and geometry.

Characterization and H2-O2 reactivity of noble nano-metal tailored single wall nano-carbons

International Nuclear Information System (INIS)

K Kaneko; T Itoh; E Bekyarova; H Kanoh; S Utsumi; H Tanaka; M Yudasaka; S Iijima; S Iijima

2005-01-01

Full text of publication follows: Single wall carbon nano-tube (SWNT) and single wall carbon nano-horn (SWNH) have nano-spaces in their particles and the nano-spaces become open by oxidation. In particular, SWNH forms a unique colloidal structure which has micropores and meso-pores between the SWNH particles. Although non-treated SWNH colloids have quasi-one dimensional nano-pores [1], oxidized SWNH colloids have both of interstitial and internal nano-pores [2-5]. SWNH colloids show excellent supercritical methane storage ability [6], molecular sieving effect [7], and unique hydrogen adsorption characteristic [8]. Selective adsorptivity of SWNH colloids for H 2 and D 2 due to uncertainty principle of those molecules was shown [9-10]. As SWNH has no metallic impurities, we can study the effect of tailoring of metallic nano-particles on the surface activities of SWNH [11]. We tailored Pd or Pt nano-particles on SWNH and SWNH oxidized at 823 K (ox-SWNH) using poly[(2-oxo-pyrrolidine-1-yl)ethylene]. The oxidation of SWNH donates nano-scale windows to the single wall. The tailored metal amount was determined by TG analysis. TEM showed uniform dispersion of nano-metal particles of 2-3 nm in the diameter on SWNH. The nitrogen adsorption amount of SWNH oxidized decreases by tailoring, indicating that nano-particles are attached to the nano-scale windows. The electronic states of tailored metals were characterized by X-ray photoelectron spectroscopy. The surface activities of Pd tailored SWNH and ox-SWNH were examined for the reaction of hydrogen and oxygen near room temperature. The catalytic reactivities of Pd tailored SWNH and ox-SWNH were 4 times greater than that of Pd-dispersed activated carbon. The temperature dependence of the surface activity will be discussed with the relevance to the tube porosity. References [1] T. Ohba et al, J. Phys. Chem. In press. [2] S. Utsumi et al, J. Phys. Chem. In press. [3] C.- Min Yang, et al. Adv. Mater. In press. [4]C.M. Yang, J

6. international conference on Nano-technology in Carbon: from synthesis to applications of nano-structured carbon and related materials

International Nuclear Information System (INIS)

2004-01-01

This is the sixth international conference sponsored this year by the French Carbon Group (GFEC), the European Research Group on Nano-tubes GDRE 'Nano-E', in collaboration with the British Carbon Group and the 'Institut des Materiaux Jean Rouxel' (local organizer). The aim of this conference is to promote carbon science in the nano-scale as, for example, nano-structured carbons, nano-tubes, nano-wires, fullerenes, etc. This conference is designed to introduce those with an interest in materials to current research in nano-technology and to bring together research scientists working in various disciplines in the broad area of nano-structured carbons, nano-tubes and fullerene-related nano-structures. Elemental carbon is the simplest exemplar of this nano-technology based on covalent bonding, however other systems (for example containing hetero-atoms) are becoming important from a research point of view, and provide alternative nano-materials with unique properties opening a broad field of applications. Nano-technology requires an understanding of these materials on a structural and textural point of view and this will be the central theme. This year the conference will feature sessions on: S1. Control and synthesis of nano-materials 1.1 Nano-structured carbons: pyrolysis of polymers, activation, templates,... 1.2 Nano-tubes: Catalytic method, HiPCO, graphite vaporization, electrolysis,... 1.3 Fullerenes S2. Chemistry of carbon nano-materials 2.1 Purification of carbon nano-tubes 2.2 Functionalization - Self-assembling S3. Structural characterization S4. Theory and modelling S5. Relationship between structure and properties S6. Applications Water and air purification, Gas and energy storage, Composite materials, Field emission, Nano-electronics, Biotechnology,... S7. Environmental impact. Only one paper concerning carbon under irradiation has been added to the INIS database. (authors)

Editorial Nano structures for Medicine and Pharmaceuticals

International Nuclear Information System (INIS)

Xing-Jie, L.; Kumar, A.; Donglu, S.; Daxiang, C.

2012-01-01

The rapid developments in nano structured materials and nano technology will have profound impact in many areas of biomedical applications including delivery of drugs and biomolecules, tissue engineering, detection of bio markers, cancer diagnosis, cancer therapy, and imaging. This field is expanding quickly, and a lot of work is ongoing in the design, characterization, synthesis, and application of materials, for controlling shape and size at nanometer scale to develop highly advanced materials for biomedical application and even to design better pharmaceutical products. In recent years, novel nano structure with multi functionalities has been focused on the use of nano structures toward solving problems of biology and medicine. The main scope of this special issue is to demonstrate the latest achievement of nano technology and its application in nano medicine particularly in new approaches for drug delivery such as targeted drug delivery system, nano structure for drug storage, nano materials for tissue engineering, medical diagnosis and treatment, and generation of new kinds of materials from biological sources. Therefore, many critical issues in nano structured materials, particularly their applications in biomedicine, must be addressed before clinical applications. This special issue devotes several review and research articles encompassing various aspects of nano materials for medicine and pharmaceuticals.

Comparison on exfoliated graphene nano-sheets and triturated graphite nano-particles for mode-locking the Erbium-doped fibre lasers

Science.gov (United States)

Yang, Chun-Yu; Lin, Yung-Hsiang; Wu, Chung-Lun; Cheng, Chih-Hsien; Tsai, Din-Ping; Lin, Gong-Ru

2018-06-01

Comparisons on exfoliated graphene nano-sheets and triturated graphite nano-particles for mode-locking the Erbium-doped fiber lasers (EDFLs) are performed. As opposed to the graphite nano-particles obtained by physically triturating the graphite foil, the tri-layer graphene nano-sheets is obtained by electrochemically exfoliating the graphite foil. To precisely control the size dispersion and the layer number of the exfoliated graphene nano-sheet, both the bias of electrochemical exfoliation and the speed of centrifugation are optimized. Under a threshold exfoliation bias of 3 volts and a centrifugation at 1000 rpm, graphene nano-sheets with an average diameter of 100  ±  40 nm can be obtained. The graphene nano-sheets with an area density of 15 #/µm2 are directly imprinted onto the end-face of a single-mode fiber made patchcord connector inside the EDFL cavity. Such electrochemically exfoliated graphene nano-sheets show comparable saturable absorption with standard single-graphene and perform the self-amplitude modulation better than physically triturated graphite nano-particles. The linear transmittance and modulation depth of the inserted graphene nano-sheets are 92.5% and 53%, respectively. Under the operation with a power gain of 21.5 dB, the EDFL can be passively mode-locked to deliver a pulsewidth of 454.5 fs with a spectral linewidth of 5.6 nm. The time-bandwidth product of 0.31 is close to the transform limit. The Kelly sideband frequency spacing of 1.34 THz is used to calculate the chirp coefficient as  ‑0.0015.

Mitochondrial-targeted DNA delivery using a DF-MITO-Porter, an innovative nano carrier with cytoplasmic and mitochondrial fusogenic envelopes

International Nuclear Information System (INIS)

Yamada, Yuma; Kawamura, Eriko; Harashima, Hideyoshi

2012-01-01

Mitochondrial gene therapy has the potential for curing a variety of diseases that are associated with mitochondrial DNA mutations and/or defects. To achieve this, it will be necessary to deliver therapeutic agents into the mitochondria in diseased cells. A number of mitochondrial drug delivery systems have been reported to date. However, reports of mitochondrial-targeted DNA delivery are limited. To achieve this, the therapeutic agent must be taken up by the cell (1), after which, the multi-processes associated with intracellular trafficking must be sophisticatedly regulated so as to release the agent from the endosome and deliver it to the cytosol (2) and to pass through the mitochondrial membrane (3). We report herein on the mitochondrial delivery of oligo DNA as a model therapeutic using a Dual Function (DF)-MITO-Porter, an innovative nano carrier designed for mitochondrial delivery. The critical structural elements of the DF-MITO-Porter include mitochondria-fusogenic inner envelopes and endosome-fusogenic outer envelopes, modified with octaarginine which greatly assists in cellular uptake. Inside the cell, the carrier passes through the endosomal and mitochondrial membranes via step-wise membrane fusion. When the oligo DNA was packaged in the DF-MITO-Porter, cellular uptake efficiency was strongly enhanced. Intracellular observation using confocal laser scanning microscopy showed that the DF-MITO-Porter was effectively released from endosomes. Moreover, the findings confirmed that the mitochondrial targeting activity of the DF-MITO-Porter was significantly higher than that of a carrier without outer endosome-fusogenic envelopes. These results support the conclusion that mitochondrial-targeted DNA delivery using a DF-MITO-Porter can be achieved when intracellular trafficking is optimally regulated.

Mitochondrial-targeted DNA delivery using a DF-MITO-Porter, an innovative nano carrier with cytoplasmic and mitochondrial fusogenic envelopes

Energy Technology Data Exchange (ETDEWEB)

Yamada, Yuma; Kawamura, Eriko; Harashima, Hideyoshi, E-mail: harasima@pharm.hokudai.ac.jp [Hokkaido University, Laboratory for Molecular Design of Pharmaceutics, Faculty of Pharmaceutical Sciences (Japan)

2012-08-15

Mitochondrial gene therapy has the potential for curing a variety of diseases that are associated with mitochondrial DNA mutations and/or defects. To achieve this, it will be necessary to deliver therapeutic agents into the mitochondria in diseased cells. A number of mitochondrial drug delivery systems have been reported to date. However, reports of mitochondrial-targeted DNA delivery are limited. To achieve this, the therapeutic agent must be taken up by the cell (1), after which, the multi-processes associated with intracellular trafficking must be sophisticatedly regulated so as to release the agent from the endosome and deliver it to the cytosol (2) and to pass through the mitochondrial membrane (3). We report herein on the mitochondrial delivery of oligo DNA as a model therapeutic using a Dual Function (DF)-MITO-Porter, an innovative nano carrier designed for mitochondrial delivery. The critical structural elements of the DF-MITO-Porter include mitochondria-fusogenic inner envelopes and endosome-fusogenic outer envelopes, modified with octaarginine which greatly assists in cellular uptake. Inside the cell, the carrier passes through the endosomal and mitochondrial membranes via step-wise membrane fusion. When the oligo DNA was packaged in the DF-MITO-Porter, cellular uptake efficiency was strongly enhanced. Intracellular observation using confocal laser scanning microscopy showed that the DF-MITO-Porter was effectively released from endosomes. Moreover, the findings confirmed that the mitochondrial targeting activity of the DF-MITO-Porter was significantly higher than that of a carrier without outer endosome-fusogenic envelopes. These results support the conclusion that mitochondrial-targeted DNA delivery using a DF-MITO-Porter can be achieved when intracellular trafficking is optimally regulated.

Synthesis of Boron Nano wires, Nano tubes, and Nano sheets

International Nuclear Information System (INIS)

Patel, R.B.; Chou, T.; Iqbal, Z.

2014-01-01

The synthesis of boron nano wires, nano tubes, and nano sheets using a thermal vapor deposition process is reported. This work confirms previous research and provides a new method capable of synthesizing boron nano materials. The materials were made by using various combinations of MgB 2 , Mg(BH 4 ) 2 , MCM-41, NiB, and Fe wire. Unlike previously reported methods, a nanoparticle catalyst and a silicate substrate are not required for synthesis. Two types of boron nano wires, boron nano tubes, and boron nano sheets were made. Their morphology and chemical composition were determined through the use of scanning electron microscopy, transmission electron microscopy, and electron energy loss spectroscopy. These boron-based materials have potential for electronic and hydrogen storage applications.

Kinetics of nitrate adsorption and reduction by nano-scale zero valent iron (NZVI): Effect of ionic strength and initial pH

DEFF Research Database (Denmark)

Kim, Do-Gun; Hwang, Yuhoon; Shin, Hang-Sik

2016-01-01

Kinetic models for pollutants reduction by Nano-scale Zero Valent Iron (NZVI) were tested in this study to gain a better understanding and description of the reaction. Adsorption kinetic models and a heterogeneous catalytic reaction kinetic equation were proposed for nitrate removal and for ammon...

USE OF COMPETITIVE DNA HYBRIDIZATION TO IDENTIFY DIFFERENCES IN THE GENOMES OF TWO CLOSELY RELATED FECAL INDICATOR BACTERIA

Science.gov (United States)

Although recent technological advances in DNA sequencing and computational biology now allow scientists to compare entire microbial genomes, comparisons of closely related bacterial species and individual isolates by whole-genome sequencing approaches remains prohibitively expens...

Structural Design of a Compact in-Plane Nano-Grating Accelerometer

International Nuclear Information System (INIS)

Yao Bao-Yin; Zhou Zhen; Feng Li-Shuang; Wang Wen-Pu; Wang Xiao

2012-01-01

A combination of large mass, weak spring and nano-grating is the key for a nano-grating accelerometer to measure nano-G acceleration. A novel compact nano-grating accelerometer integrating a large mass with nano-grating is proposed. First, the numbers of diffraction orders are calculated. Then, structure parameters are optimized by finite element analysis to achieve a high sensitivity in an ideal vibration mode. Finally, we design the fabrication method to form such a compact nano-grating accelerometer and successfully fabricate the uniform and well-designed nano-gratings with a period of 847 nm, crater of 451 nm by an FIB/SEM dual beam system. Based on the ANSYS simulation, a nano-grating accelerometer is predicted to work in the first modal and enables the accelerometer to have displacement sensitivity at 197 nm/G with a measurement range of ±1 G, corresponding to zeroth diffraction beam optical sensitivity 1%/mG. The nano-gratings fabricated are very close to those designed ones within experimental error to lay the foundation for the sequent fabrication. These results provide a theoretical basis for the design and fabrication of nano-grating accelerometers

Removing Pathogens Using Nano-Ceramic-Fiber Filters

Science.gov (United States)

Tepper, Frederick; Kaledin, Leonid

2005-01-01

A nano-aluminum-oxide fiber of only 2 nanometers in diameter was used to develop a ceramic-fiber filter. The fibers are electropositive and, when formulated into a filter material (NanoCeram(TradeMark)), would attract electro-negative particles such as bacteria and viruses. The ability to detect and then remove viruses as well as bacteria is of concern in space cabins since they may be carried onboard by space crews. Moreover, an improved filter was desired that would polish the effluent from condensed moisture and wastewater, producing potable drinking water. A laboratory- size filter was developed that was capable of removing greater than 99.9999 percent of bacteria and virus. Such a removal was achieved at flow rates hundreds of times greater than those through ultraporous membranes that remove particles by sieving. Because the pore size of the new filter was rather large as compared to ultraporous membranes, it was found to be more resistant to clogging. Additionally, a full-size cartridge is being developed that is capable of serving a full space crew. During this ongoing effort, research demonstrated that the filter media was a very efficient adsorbent for DNA (deoxyribonucleic acid), RNA (ribonucleic acid), and endotoxins. Since the adsorption is based on the charge of the macromolecules, there is also a potential for separating proteins and other particulates on the basis of their charge differences. The separation of specific proteins is a major new thrust of biotechnology. The principal application of NanoCeram filters is based on their ability to remove viruses from water. The removal of more than 99.9999 percent of viruses was achieved by a NanoCeram polishing filter added to the effluent of an existing filtration device. NanoCeram is commercially available in laboratory-size filter discs and in the form of a syringe filter. The unique characteristic of the filter can be demonstrated by its ability to remove particulate dyes such as Metanyl yellow. Its

Combining combing and secondary ion mass spectrometry to study DNA on chips using 13C and 15N labeling [version 1; referees: 2 approved

Directory of Open Access Journals (Sweden)

Armelle Cabin-Flaman

2016-06-01

Full Text Available Dynamic secondary ion mass spectrometry (D-SIMS imaging of combed DNA – the combing, imaging by SIMS or CIS method – has been developed previously using a standard NanoSIMS 50 to reveal, on the 50 nm scale, individual DNA fibers labeled with different, non-radioactive isotopes in vivo and to quantify these isotopes. This makes CIS especially suitable for determining the times, places and rates of DNA synthesis as well as the detection of the fine-scale re-arrangements of DNA and of molecules associated with combed DNA fibers. Here, we show how CIS may be extended to 13C-labeling via the detection and quantification of the 13C14N- recombinant ion and the use of the 13C:12C ratio, we discuss how CIS might permit three successive labels, and we suggest ideas that might be explored using CIS.

Evaluation of dose dependent antimicrobial activity of self-assembled chitosan, nano silver and chitosan-nano silver composite against several pathogens.

Science.gov (United States)

Tareq, Foysal Kabir; Fayzunnesa, Mst; Kabir, Md Shahariar; Nuzat, Musrat

2018-01-01

The aim of this investigation to preparation of silver nanoparticles organized chitosan nano polymer, which effective against microbial and pathogens, when apply to liquid medium and edible food products surface, will rescue the growth of microbes. Self-assembly approach used to synthesis of silver nanoparticles and silver nanoparticles organized chitosan nano polymer. Silver nanoparticles and silver nanoparticles organized chitosan nano polymer and film characterized using Ultra-violate visible spectrometer (UV-vis), X-ray diffraction (X-ray), and Scanning electronic microscope (SEM). The crystalline structured protein capped nano silver successfully synthesized at range of 12 nm-29 nm and organized into chitosan nano polymer. Antimicrobial ingredient in liquid medium and food product surface provide to rescue oxidative change and growth of microorganism to provide higher safety. The silver nanoparticles organized chitosan nano polymer caused the death of microorganism. The materials in nano scale synthesized successfully using self-assembly method, which showed good antimicrobial properties. Copyright © 2017 Elsevier Ltd. All rights reserved.

Synthesise of Zn O nano wires by direct oxidation method

International Nuclear Information System (INIS)

Farbod, M.; Ahangarpour, A.

2007-01-01

Zn O is a semiconductor which has a direct and wide energy band which is about 3.37 eV at room temperature. It has various applications from UV lasers, sensitive sensors, solar cells to photo catalysis applications. Zn O has different nano structures such as nanoparticles, nano wires, nano rods, nano tubes and nano belts. The one dimensional Zn O nano structures such as nano wires are very important because of their applications in nano electronics and nano photonics so different methods have been proposed to synthesize them. In this work large scale of Zn O nano wires are produced by direct oxidation a Zn substrate (which was cleaned by chemical methods) in air or oxygen atmosphere at 400 d eg C . Nano wires were investigated by scanning electron microscopy and energy dispersive x-ray measurements. Their diameter is about 30-150 nanometer and their length is about several micrometer. This method which acts without any catalyst is a convenient method to synthesis semiconductor nano wires.

Nano-technology and nano-toxicology.

Science.gov (United States)

Maynard, Robert L

2012-01-01

Rapid developments in nano-technology are likely to confer significant benefits on mankind. But, as with perhaps all new technologies, these benefits are likely to be accompanied by risks, perhaps by new risks. Nano-toxicology is developing in parallel with nano-technology and seeks to define the hazards and risks associated with nano-materials: only when risks have been identified they can be controlled. This article discusses the reasons for concern about the potential effects on health of exposure to nano-materials and relates these to the evidence of the effects on health of the ambient aerosol. A number of hypotheses are proposed and the dangers of adopting unsubstantiated hypotheses are stressed. Nano-toxicology presents many challenges and will need substantial financial support if it is to develop at a rate sufficient to cope with developments in nano-technology.

One-Dimensional SnO2 Nano structures: Synthesis and Applications

International Nuclear Information System (INIS)

Pan, J.; Shen, H.; Mathur, S.; Pan, J.

2012-01-01

Nano scale semiconducting materials such as quantum dots (0-dimensional) and one-dimensional (1D) structures, like nano wires, nano belts, and nano tubes, have gained tremendous attention within the past decade. Among the variety of 1D nano structures, tin oxide (SnO 2 ) semiconducting nano structures are particularly interesting because of their promising applications in optoelectronic and electronic devices due to both good conductivity and transparence in the visible region. This article provides a comprehensive review of the recent research activities that focus on the rational synthesis and unique applications of 1D SnO 2 nano structures and their optical and electrical properties. We begin with the rational design and synthesis of 1D SnO 2 nano structures, such as nano tubes, nano wires, nano belts, and some heterogeneous nano structures, and then highlight a range of applications (e.g., gas sensor, lithium-ion batteries, and nano photonics) associated with them. Finally, the review is concluded with some perspectives with respect to future research on 1D SnO 2 nano structures

The nano-science of C sub 6 0 molecule

CERN Document Server

Rafii-Tabar, H

2002-01-01

Over the past few years, nano-science and its associated nano-technology have emerged into prominence in research institutions across the world. They have brought about new scientific and engineering paradigms, allowing for the manipulation of single atoms and molecules, designing and fabricating new materials, atom-by-atom, and devices that operate on significantly reduced time and length scales. One important area of research in nano-science and nano technology is carbon-based physics in the form of fullerene physics. The C sub 6 0 molecule, and other cage-like fullerenes, together with carbon nano tubes provide objects that can be combined to generate three-dimensional functional structures for use in the anticipated nano-technology of future. The unique properties of C sub 6 0 can also be exploited in designing nano-phase thin films with applications in nano-scope device technology and processes such as nano-lithography. This requires a deep understanding of the highly complex process of adsorption of thi...

Topological superfluids confined in a regular nano-scale slab geometry

Energy Technology Data Exchange (ETDEWEB)

Saunders, John; Bennett, Robert; Levitin, Lev; Casey, Andrew; Cowan, Brian [Department of Physics, Royal Holloway University of London, Egham, Surrey, TW20 0EX (United Kingdom); Parpia, Jeevak [Department of Physics, Cornell University, Ithaca, NY 14853 (United States); Drung, Dietmar; Schurig, Thomas [Physikalisch-Technische Bundesanstalt, Abbestrasse 2-12, D-19587, Berlin (Germany)

2012-07-01

Superfluid 3He confined in a regular nano-fabricated slab geometry provides a model system for the investigation of surface and thin film effects in a p-wave superfluid. We have fabricated and cooled such samples to well below 1 mK for the first time, and investigated their NMR response, exploiting a SQUID NMR spectrometer of exquisite sensitivity. We have used NMR on a 650 nm thick superfluid slab to identify the profound effect of confinement on the relative stability of the A and B phases and to make quantitative measurements of the suppression and surface induced distortion of the order parameter. In these systems the effective confinement length scale (slab thickness/superfluid coherence length) is the new tuning parameter. Increasing confinement should stabilize new p-wave superfluid states of matter, such as the quasi-2D gapped A phase or the planar phase. Nanofluidic samples of superfluid 3He promise a route to explore topological superfluids and their surface, edge and defect-bound excitations under well controlled conditions.

Nanostructured silicate substituted calcium phosphate (NanoSiCaPs) nanoparticles — Efficient calcium phosphate based non-viral gene delivery systems

Energy Technology Data Exchange (ETDEWEB)

Shekhar, Sudhanshu [Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Center for Complex Engineered Multifunctional Materials, University of Pittsburgh, Pittsburgh, PA 15261 (United States); McGowan Institute of Regenerative Medicine, University of Pittsburgh, PA 15261 (United States); Roy, Abhijit; Hong, Daeho [Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Kumta, Prashant N., E-mail: pkumta@pitt.edu [Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, PA 15260 (United States); Center for Complex Engineered Multifunctional Materials, University of Pittsburgh, Pittsburgh, PA 15261 (United States); McGowan Institute of Regenerative Medicine, University of Pittsburgh, PA 15261 (United States)

2016-12-01

Nanostructured ceramic particles, particularly, nanoparticles of calcium phosphate (CaP) remain an attractive option among the various types of non-viral gene delivery vectors studied because of their safety, biocompatibility, biodegradability, and ease of handling as well as their adsorptive capacity for DNA. We have accordingly developed an enhanced version of nanostructured calcium phosphates (NanoCaPs), by substituting known amounts of silicate for phosphate in the hydroxyapatite (HA) lattice (NanoSiCaPs). Results indicate that in addition to the excellent transfection levels exhibited by un-substituted NanoCaPs alone in vitro, an additional 20–50% increase in transfection is observed for NanoCaPs containing 8.3–50 mol% silicate aptly called NanoSiCaPs, owing to its rapid dissolution properties enabling nanoparticles escaping the lysosomal degradation. However, high silicate substitution (> 50 mol%) resulted in a drastic decline in transfection as the synthesized NanoCaPs deviated far from the characteristic hydroxyapatite phase formed as evidenced by the materials characterization results. - Highlights: • Successful demonstration of nanostructured NanoSiCaPs formation • Demonstration of superior transfection of NanoSiCaPs contrasted to NanoCaPs • Silicate substitution leads to smaller aggregates of nanoparticle complexes. • Enhanced dissolution of NanoSiCaPs demonstrated • Faster NanoSiCaPs dissolution leads to escape of pDNA from lysosomal degradation.

Murine liver damage caused by exposure to nano-titanium dioxide

International Nuclear Information System (INIS)

Hong, Jie; Zhang, Yu-Qing

2016-01-01

Due to its unique physiochemical properties, nano-titanium dioxide (nano-TiO_2) is widely used in all aspects of people’s daily lives, bringing it into increasing contact with humans. Thus, this material’s security issues for humans have become a heavily researched subject. Nano-TiO_2 can enter the body through the mouth, skin, respiratory tract or in other ways, after which it enters the blood circulation and is deposited in the liver, changing biochemical indicators and causing liver inflammation. Meanwhile, the light sensitivity of these nanoparticles allows them to become media-generating reactive oxygen species (ROS), causing an imbalance between oxidation and anti-oxidation that leads to oxidative stress and liver damage. Nano-TiO_2 can be transported into cells via phagocytosis, where the nanoparticles bind to the mitochondrial membrane, resulting in the disintegration of the membrane and the electron transport chain within the mitochondria. Thus, more ROS are produced. Nano-TiO_2 can also enter the nucleus, where it can directly embed into or indirectly affect DNA, thereby causing DNA breakage or affecting gene expression. These effects include increased mRNA and protein expression levels of inflammation-related factors and decreased mRNA and protein expression levels of IκB and IL-2, resulting in inflammation. Long-term inflammation of the liver causes HSC cell activation, and extracellular matrix (ECM) deposition is promoted by multiple signalling pathways, resulting in liver fibrosis. In this paper, the latest progress on murine liver injury induced by environmental TiO_2 is systematically described. The toxicity of nano-TiO_2 also depends on size, exposure time, surface properties, dosage, administration route, and its surface modification. Therefore, its toxic effects in humans should be studied in greater depth. This paper also provides useful reference information regarding the safe use of nano-TiO_2 in the future. (topical review)

Atom probe characterization of nano-scaled features in irradiated Eurofer and ODS Eurofer steel

International Nuclear Information System (INIS)

Rogozkin, S.; Aleev, A.; Nikitin, A.; Zaluzhnyi, A.; Vladimirov, P.; Moeslang, A.; Lindau, R.

2009-01-01

Outstanding performance of oxide dispersion strengthened (ODS) steels at high temperatures and up to high doses allowed to consider them as potential candidates for fusion and fission power plants. At the same time their mechanical parameters strongly correlate with number density of oxide particles and their size. It is believed that fine particles are formed at the last stage of sophisticated production procedures and play a crucial role in higher heat- and radiation resistance in comparison with conventional materials. However, due to their small size - only few nanometers, characterization of such objects requires considerable efforts. Recent study of ODS steel by tomographic atom probe, the most appropriate technique in this case, shown considerable stability of these particles under high temperatures and ion-irradiation. However, these results were obtained for 12/14% Cr with addition of 0.3% Y 2 O 3 and titanium which is inappropriate in case of ODS Eurofer 97 and possibility to substitute neutron by ion irradiation is still under consideration. In this work effect of neutron irradiation on nanostructure behaviour of ODS Eurofer are investigated. Irradiation was performed on research reactor BOR-60 in SSC RF RIAR (Dimitrovgrad, Russia) up to 30 dpa at 280 deg. C and 580 deg. C. Recent investigation of unirradiated state revealed high number density of nano-scaled features (nano-clusters) even without addition of Ti in steel. It was shown that vanadium played significant role in nucleation process and core of nano-clusters was considerably enriched with it. In irradiated samples solution of vanadium in matrix was observed while the size of particles stayed practically unchanged. Also no nitrogen was detected in these particles in comparison with unirradiated state where bond energy of N with V was considered to be high as VN 2+ ions were detected on mass-spectra. (author)

Increasing Possibilities of Nano suspension

International Nuclear Information System (INIS)

Sutradhar, K.B.; Khatun, S.; Luna, I.P.

2013-01-01

Nowadays, a very large proportion of new drug candidates emerging from drug discovery programmes are water insoluble and thus poorly bioavailable. To avoid this problem, nano technology for drug delivery has gained much interest as a way to improve the solubility problems. Nano refers to particles size range of 1-1000 nm. The reduction of drug particles into the submicron range leads to a significant increase in the dissolution rate and therefore enhances bioavailability. Nanosuspensions are part of nano technology. This interacts with the body at subcellular (i.e., molecular) scales with a high degree of specificity and can be potentially translated into targeted cellular and tissue-specific clinical applications designed to achieve maximal therapeutic efficacy with minimal side effects. Production of drugs as nanosuspensions can be developed for drug delivery systems as an oral formulation and no noral administration. Here, this review describes the methods of pharmaceutical nano suspension production including advantages and disadvantages, potential benefits, characterization tests, and pharmaceutical applications in drug delivery

Dissociative electron attachment to DNA-diamine thin films: Impact of the DNA close environment on the OH{sup −} and O{sup −} decay channels

Energy Technology Data Exchange (ETDEWEB)

Boulanouar, Omar; Fromm, Michel; Mavon, Christophe [UMR CNRS 6249 Chrono-Environnement, Laboratoire de Chimie Physique et Rayonnements – Alain Chambaudet, LRC CEA, Université de Franche-Comté, 16 route de Gray, F-25030 Besançon cedex (France); Cloutier, Pierre; Sanche, Léon [Groupe en Sciences des Radiations, Département de Médecine Nucléaire et de Radiobiologie, Faculté de Médecine, Université de Sherbrooke, Québec J1H 5N4 (Canada)

2013-08-07

We measure the desorption of anions stimulated by the impact of 0–20 eV electrons on highly uniform thin films of plasmid DNA-diaminopropane. The results are accurately correlated with film thickness and composition by AFM and XPS measurements, respectively. Resonant structures in the H{sup −}, O{sup −}, and OH{sup −} yield functions are attributed to the decay of transient anions into the dissociative electron attachment (DEA) channel. The diamine induces ammonium-phosphate bridges along the DNA backbone, which suppresses the DEA O{sup −} channel and in counter-part increases considerably the desorption of OH{sup −}. The close environment of the phosphate groups may therefore play an important role in modulating the rate and type of DNA damages induced by low energy electrons.

Software Architecture for a Virtual Environment for Nano Scale Assembly (VENSA).

Science.gov (United States)

Lee, Yong-Gu; Lyons, Kevin W; Feng, Shaw C

2004-01-01

A Virtual Environment (VE) uses multiple computer-generated media to let a user experience situations that are temporally and spatially prohibiting. The information flow between the user and the VE is bidirectional and the user can influence the environment. The software development of a VE requires orchestrating multiple peripherals and computers in a synchronized way in real time. Although a multitude of useful software components for VEs exists, many of these are packaged within a complex framework and can not be used separately. In this paper, an architecture is presented which is designed to let multiple frameworks work together while being shielded from the application program. This architecture, which is called the Virtual Environment for Nano Scale Assembly (VENSA), has been constructed for interfacing with an optical tweezers instrument for nanotechnology development. However, this approach can be generalized for most virtual environments. Through the use of VENSA, the programmer can rely on existing solutions and concentrate more on the application software design.

Large-scale fabrication of superhydrophobic polyurethane/nano-Al2O3 coatings by suspension flame spraying for anti-corrosion applications

Science.gov (United States)

Chen, Xiuyong; Yuan, Jianhui; Huang, Jing; Ren, Kun; Liu, Yi; Lu, Shaoyang; Li, Hua

2014-08-01

This study aims to further enhance the anti-corrosion performances of Al coatings by constructing superhydrophobic surfaces. The Al coatings were initially arc-sprayed onto steel substrates, followed by deposition of polyurethane (PU)/nano-Al2O3 composites by a suspension flame spraying process. Large-scale corrosion-resistant superhydrophobic PU/nano-Al2O3-Al coatings were successfully fabricated. The coatings showed tunable superhydrophilicity/superhydrophobicity as achieved by changing the concentration of PU in the starting suspension. The layer containing 2.0 wt.%PU displayed excellent hydrophobicity with the contact angle of ∼151° and the sliding angle of ∼6.5° for water droplets. The constructed superhydrophobic coatings showed markedly improved anti-corrosion performances as assessed by electrochemical corrosion testing carried out in 3.5 wt.% NaCl solution. The PU/nano-Al2O3-Al coatings with superhydrophobicity and competitive anti-corrosion performances could be potentially used as protective layers for marine infrastructures. This study presents a promising approach for fabricatiing superhydrophobic coatings for corrosion-resistant applications.

Nano technology

International Nuclear Information System (INIS)

Lee, In Sik

2002-03-01

This book is introduction of nano technology, which describes what nano technology is, alpha and omega of nano technology, the future of Korean nano technology and human being's future and nano technology. The contents of this book are nano period is coming, a engine of creation, what is molecular engineering, a huge nano technology, technique on making small things, nano materials with exorbitant possibility, the key of nano world the most desirable nano technology in bio industry, nano development plan of government, the direction of development for nano technology and children of heart.

Ecological assessment of nano-enabled supercapacitors for automotive applications

Science.gov (United States)

Weil, M.; Dura, H.; Shimon, B.; Baumann, M.; Zimmermann, B.; Ziemann, S.; Lei, C.; Markoulidis, F.; Lekakou, T.; Decker, M.

2012-09-01

New materials on nano scale have the potential to overcome existing technical barriers and are one of the most promising key technologies to enable the decoupling of economic growth and resource consumption. Developing these innovative materials for industrial applications means facing a complex quality profile, which includes among others technical, economic, and ecological aspects. So far the two latter aspects are not sufficiently included in technology development, especially from a life cycle point of view. Supercapacitors are considered a promising option for electric energy storage in hybrid and full electric cars. In comparison with presently used lithium based electro chemical storage systems supercapacitors possess a high specific power, but a relatively low specific energy. Therefore, the goal of ongoing research is to develop a new generation of supercapacitors with high specific power and high specific energy. To reach this goal particularly nano materials are developed and tested on cell level. In the presented study the ecological implications (regarding known environmental effects) of carbon based nano materials are analysed using Life Cycle Assessment (LCA). Major attention is paid to efficiency gains of nano particle production due to scaling up of such processes from laboratory to industrial production scales. Furthermore, a developed approach will be displayed, how to assess the environmental impact of nano materials on an automotive system level over the whole life cycle.

Ecological assessment of nano-enabled supercapacitors for automotive applications

International Nuclear Information System (INIS)

Weil, M; Dura, H; Shimon, B; Baumann, M; Zimmermann, B; Ziemann, S; Decker, M; Lei, C; Markoulidis, F; Lekakou, T

2012-01-01

New materials on nano scale have the potential to overcome existing technical barriers and are one of the most promising key technologies to enable the decoupling of economic growth and resource consumption. Developing these innovative materials for industrial applications means facing a complex quality profile, which includes among others technical, economic, and ecological aspects. So far the two latter aspects are not sufficiently included in technology development, especially from a life cycle point of view. Supercapacitors are considered a promising option for electric energy storage in hybrid and full electric cars. In comparison with presently used lithium based electro chemical storage systems supercapacitors possess a high specific power, but a relatively low specific energy. Therefore, the goal of ongoing research is to develop a new generation of supercapacitors with high specific power and high specific energy. To reach this goal particularly nano materials are developed and tested on cell level. In the presented study the ecological implications (regarding known environmental effects) of carbon based nano materials are analysed using Life Cycle Assessment (LCA). Major attention is paid to efficiency gains of nano particle production due to scaling up of such processes from laboratory to industrial production scales. Furthermore, a developed approach will be displayed, how to assess the environmental impact of nano materials on an automotive system level over the whole life cycle.

Hybrid micro-/nano-particle image velocimetry for 3D3C multi-scale velocity field measurement in microfluidics

International Nuclear Information System (INIS)

Min, Young Uk; Kim, Kyung Chun

2011-01-01

The conventional two-dimensional (2D) micro-particle image velocimetry (micro-PIV) technique has inherent bias error due to the depth of focus along the optical axis to measure the velocity field near the wall of a microfluidics device. However, the far-field measurement of velocity vectors yields good accuracy for micro-scale flows. Nano-PIV using the evanescent wave of total internal reflection fluorescence microscopy can measure near-field velocity vectors within a distance of around 200 nm from the solid surface. A micro-/nano-hybrid PIV system is proposed to measure both near- and far-field velocity vectors simultaneously in microfluidics. A near-field particle image can be obtained by total internal reflection fluorescence microscopy using nanoparticles, and the far-field velocity vectors are measured by three-hole defocusing micro-particle tracking velocimetry (micro-PTV) using micro-particles. In order to identify near- and far-field particle images, lasers of different wavelengths are adopted and tested in a straight microchannel for acquiring the three-dimensional three-component velocity field. We found that the new technique gives superior accuracy for the velocity profile near the wall compared to that of conventional nano-PIV. This method has been successfully applied to precisely measure wall shear stress in 2D microscale Poiseulle flows

High performance nano-composite technology development

International Nuclear Information System (INIS)

Kim, Whung Whoe; Rhee, C. K.; Kim, S. J.; Park, S. D.; Kim, E. K.; Jung, S. Y.; Ryu, H. J.; Hwang, S. S.; Kim, J. K.; Hong, S. M.; Chea, Y. B.; Choi, C. H.; Kim, S. D.; Cho, B. G.; Lee, S. H.

1999-06-01

The trend of new material development are being to carried out not only high performance but also environmental attraction. Especially nano composite material which enhances the functional properties of components, extending the component life resulting to reduced the wastes and environmental contamination, has a great effect on various industrial area. The application of nano composite, depends on the polymer matrix and filler materials, has various application from semiconductor to medical field. In spite of nano composite merits, nano composite study are confined to a few special materials as a lab, scale because a few technical difficulties are still on hold. Therefore, the purpose of this study establishes the systematical planning to carried out the next generation projects on order to compete with other countries and overcome the protective policy of advanced countries with grasping over sea's development trends and our present status. (author).

High performance nano-composite technology development

Energy Technology Data Exchange (ETDEWEB)

Kim, Whung Whoe; Rhee, C. K.; Kim, S. J.; Park, S. D. [KAERI, Taejon (Korea, Republic of); Kim, E. K.; Jung, S. Y.; Ryu, H. J. [KRICT, Taejon (Korea, Republic of); Hwang, S. S.; Kim, J. K.; Hong, S. M. [KIST, Taejon (Korea, Republic of); Chea, Y. B. [KIGAM, Taejon (Korea, Republic of); Choi, C. H.; Kim, S. D. [ATS, Taejon (Korea, Republic of); Cho, B. G.; Lee, S. H. [HGREC, Taejon (Korea, Republic of)

1999-06-15

The trend of new material development are being to carried out not only high performance but also environmental attraction. Especially nano composite material which enhances the functional properties of components, extending the component life resulting to reduced the wastes and environmental contamination, has a great effect on various industrial area. The application of nano composite, depends on the polymer matrix and filler materials, has various application from semiconductor to medical field. In spite of nano composite merits, nano composite study are confined to a few special materials as a lab, scale because a few technical difficulties are still on hold. Therefore, the purpose of this study establishes the systematical planning to carried out the next generation projects on order to compete with other countries and overcome the protective policy of advanced countries with grasping over sea's development trends and our present status. (author).

Identification of the elementary structural units of the DNA damage response.

Science.gov (United States)

Natale, Francesco; Rapp, Alexander; Yu, Wei; Maiser, Andreas; Harz, Hartmann; Scholl, Annina; Grulich, Stephan; Anton, Tobias; Hörl, David; Chen, Wei; Durante, Marco; Taucher-Scholz, Gisela; Leonhardt, Heinrich; Cardoso, M Cristina

2017-06-12

Histone H2AX phosphorylation is an early signalling event triggered by DNA double-strand breaks (DSBs). To elucidate the elementary units of phospho-H2AX-labelled chromatin, we integrate super-resolution microscopy of phospho-H2AX during DNA repair in human cells with genome-wide sequencing analyses. Here we identify phospho-H2AX chromatin domains in the nanometre range with median length of ∼75 kb. Correlation analysis with over 60 genomic features shows a time-dependent euchromatin-to-heterochromatin repair trend. After X-ray or CRISPR-Cas9-mediated DSBs, phospho-H2AX-labelled heterochromatin exhibits DNA decondensation while retaining heterochromatic histone marks, indicating that chromatin structural and molecular determinants are uncoupled during repair. The phospho-H2AX nano-domains arrange into higher-order clustered structures of discontinuously phosphorylated chromatin, flanked by CTCF. CTCF knockdown impairs spreading of the phosphorylation throughout the 3D-looped nano-domains. Co-staining of phospho-H2AX with phospho-Ku70 and TUNEL reveals that clusters rather than nano-foci represent single DSBs. Hence, each chromatin loop is a nano-focus, whose clusters correspond to previously known phospho-H2AX foci.

Nano-viscosity of supercooled liquid measured by fluorescence correlation spectroscopy: Pressure and temperature dependence and the density scaling

Science.gov (United States)

Meier, G.; Gapinski, J.; Ratajczyk, M.; Lettinga, M. P.; Hirtz, K.; Banachowicz, E.; Patkowski, A.

2018-03-01

The Stokes-Einstein relation allows us to calculate apparent viscosity experienced by tracers in complex media on the basis of measured self-diffusion coefficients. Such defined nano-viscosity values can be obtained through single particle techniques, like fluorescence correlation spectroscopy (FCS) and particle tracking (PT). In order to perform such measurements, as functions of pressure and temperature, a new sample cell was designed and is described in this work. We show that this cell in combination with a long working distance objective of the confocal microscope can be used for successful FCS, PT, and confocal imaging experiments in broad pressure (0.1-100 MPa) and temperature ranges. The temperature and pressure dependent nano-viscosity of a van der Waals liquid obtained from the translational diffusion coefficient measured in this cell by means of FCS obeys the same scaling as the rotational relaxation and macro-viscosity of the system.

Transcription of hepatitis B virus covalently closed circular DNA is regulated by CpG methylation during chronic infection.

Directory of Open Access Journals (Sweden)

Yongmei Zhang

Full Text Available The persistence of hepatitis B virus (HBV infection is maintained by the nuclear viral covalently closed circular DNA (cccDNA, which serves as transcription template for viral mRNAs. Previous studies suggested that cccDNA contains methylation-prone CpG islands, and that the minichromosome structure of cccDNA is epigenetically regulated by DNA methylation. However, the regulatory effect of each CpG island methylation on cccDNA activity remains elusive. In the present study, we analyzed the distribution of CpG methylation within cccDNA in patient samples and investigated the impact of CpG island methylation on cccDNA-driven virus replication. Our study revealed the following observations: 1 Bisulfite sequencing of cccDNA from chronic hepatitis B patients indicated that CpG island I was seldom methylated, 2 CpG island II methylation was correlated to the low level of serum HBV DNA in patients, and in vitro methylation studies confirmed that CpG island II methylation markedly reduced cccDNA transcription and subsequent viral core DNA replication, 3 CpG island III methylation was associated with low serum HBsAg titers, and 4 Furthermore, we found that HBV genotype, HBeAg positivity, and patient age and liver fibrosis stage were also relevant to cccDNA CpG methylation status. Therefore, we clearly demonstrated that the status of cccDNA methylation is connected to the biological behavior of HBV. Taken together, our study provides a complete profile of CpG island methylation within HBV cccDNA and new insights for the function of CpG methylation in regulating HBV cccDNA transcription.

[Identification and analysis of Corydalis boweri, Meconopsis horridula and their close related species of the same genus by using ITS2 DNA barcode].

Science.gov (United States)

Dou, Rong-kun; Bi, Zhen-fei; Bai, Rui-xue; Ren, Yao-yao; Tan, Rui; Song, Liang-ke; Li, Di-qiang; Mao, Can-quan

2015-04-01

The study is aimed to ensure the quality and safety of medicinal plants by using ITS2 DNA barcode technology to identify Corydalis boweri, Meconopsis horridula and their close related species. The DNA of 13 herb samples including C. boweri and M. horridula from Lhasa of Tibet was extracted, ITS PCR were amplified and sequenced. Both assembled and web downloaded 71 ITS2 sequences were removed of 5. 8S and 28S. Multiple sequence alignment was completed and the intraspecific and interspecific genetic distances were calculated by MEGA 5.0, while the neighbor-joining phylogenetic trees were constructed. We also predicted the ITS2 secondary structure of C. boweri, M. horridula and their close related species. The results showed that ITS2 as DNA barcode was able to identify C. boweri, M. horridula as well as well as their close related species effectively. The established based on ITS2 barcode method provides the regular and safe detection technology for identification of C. boweri, M. horridula and their close related species, adulterants and counterfeits, in order to ensure their quality control, safe medication, reasonable development and utilization.

Theoretical study of silicon carbide under irradiation at the nano scale: classical and ab initio modelling

International Nuclear Information System (INIS)

Lucas, G.

2006-10-01

The behaviour of silicon carbide under irradiation has been studied using classical and ab initio simulations, focusing on the nano scale elementary processes. First, we have been interested in the calculation of threshold displacement energies, which are difficult to determine both experimentally and theoretically, and also the associated Frenkel pairs. In the framework of this thesis, we have carried out simulations in classical and ab initio molecular dynamics. For the classical approach, two types of potentials have been used: the Tersoff potential, which led to non satisfactory results, and a new one which has been developed during this thesis. This potential allows a better modelling of SiC under irradiation than most of the empirical potentials available for SiC. It is based on the EDIP potential, initially developed to describe defects in silicon, that we have generalized to SiC. For the ab initio approach, the feasibility of the calculations has been validated and average energies of 19 eV for the C and 38 eV for the Si sublattices have been determined, close to the values empirically used in the fusion community. The results obtained with the new potential EDIP are globally in agreement with those values. Finally, the elementary processes involved in the crystal recovery have been studied by calculating the stability of the created Frenkel pairs and determining possible recombination mechanisms with the nudged elastic band method. (author)

Micro/nano-computed tomography technology for quantitative dynamic, multi-scale imaging of morphogenesis.

Science.gov (United States)

Gregg, Chelsea L; Recknagel, Andrew K; Butcher, Jonathan T

2015-01-01

Tissue morphogenesis and embryonic development are dynamic events challenging to quantify, especially considering the intricate events that happen simultaneously in different locations and time. Micro- and more recently nano-computed tomography (micro/nanoCT) has been used for the past 15 years to characterize large 3D fields of tortuous geometries at high spatial resolution. We and others have advanced micro/nanoCT imaging strategies for quantifying tissue- and organ-level fate changes throughout morphogenesis. Exogenous soft tissue contrast media enables visualization of vascular lumens and tissues via extravasation. Furthermore, the emergence of antigen-specific tissue contrast enables direct quantitative visualization of protein and mRNA expression. Micro-CT X-ray doses appear to be non-embryotoxic, enabling longitudinal imaging studies in live embryos. In this chapter we present established soft tissue contrast protocols for obtaining high-quality micro/nanoCT images and the image processing techniques useful for quantifying anatomical and physiological information from the data sets.

Plastic deformation and failure mechanisms in nano-scale notched metallic glass specimens under tensile loading

Science.gov (United States)

Dutta, Tanmay; Chauniyal, Ashish; Singh, I.; Narasimhan, R.; Thamburaja, P.; Ramamurty, U.

2018-02-01

In this work, numerical simulations using molecular dynamics and non-local plasticity based finite element analysis are carried out on tensile loading of nano-scale double edge notched metallic glass specimens. The effect of acuteness of notches as well as the metallic glass chemical composition or internal material length scale on the plastic deformation response of the specimens are studied. Both MD and FE simulations, in spite of the fundamental differences in their nature, indicate near-identical deformation features. Results show two distinct transitions in the notch tip deformation behavior as the acuity is increased, first from single shear band dominant plastic flow localization to ligament necking, and then to double shear banding in notches that are very sharp. Specimens with moderately blunt notches and composition showing wider shear bands or higher material length scale characterizing the interaction stress associated with flow defects display profuse plastic deformation and failure by ligament necking. These results are rationalized from the role of the interaction stress and development of the notch root plastic zones.

Enhancement of the fluorescence intensity of DNA intercalators using nano-imprinted 2-dimensional photonic crystal

International Nuclear Information System (INIS)

Endo, Tatsuro; Ueda, China; Hisamoto, Hideaki; Kajita, Hiroshi; Okuda, Norimichi; Tanaka, Satoru

2013-01-01

We have fabricated polymer-based 2-dimensional photonic crystals that play a key role in enhancing the fluorescence of DNA intercalators. Highly ordered 2-dimensional photonic crystals possessing triangle-shaped and nm-sized hole arrays were fabricated on a 100 μm thick polymer film using nano-imprint lithography. Samples of double-stranded DNAs (sizes: 4361 and 48502 bp; concentration: 1 pM to 10 nM) were adsorbed on the surface of the 2-dimensional photonic crystal by electrostatic interactions and then treated with intercalators. It is found that the fluorescence intensity of the intercalator is enhanced by a factor of up to 10 compared to the enhancement in the absence of the 2-dimensional photonic crystal. Fluorescence intensity increases with increasing length and concentration of the DNAs. If the 2-dimensional photonic crystal is used as a Bragg reflection mirror, the enhancement of fluorescence intensity can be easily observed using a conventional spectrofluorometer. These results suggest that the printed photonic crystal offers a great potential for highly sensitive intercalator-based fluorescent detection of DNAs. (author)

Proposal for New Experimental Tests of the Bose-Einstein Condensation Mechanism for Low-Energy Nuclear Reaction and Transmutation Processes in Deuterium Loaded - and Nano-Scale Cavities

Science.gov (United States)

Kim, Yeong E.; Koltick, David S.; Reifenberger, Ronald G.; Zubarev, Alexander L.

2006-02-01

Most of experimental results of low-energy nuclear reaction (LENR) reported so far cannot be reproduced on demand. There have been persistent experimental results indicating that the LENR and transmutation processes in condensed matters (LENRTPCM) are surface phenomena rather than bulk phenomena. Recently proposed Bose-Einstein condensation (BEC) mechanism may provide a suitable theoretical description of the surface phenomena. New experiments are proposed and described for testing the BEC mechanism for LENR and transmutation processes in micro- and nano-scale traps. (1) We propose the use of micro- or nano-porous conducting materials as a cathode in electrolysis experiments with heavy water with or without Li in order to stabilize the active surface spots and to enhance the effect for the purpose of improving the reproducibility of excess heat generation and nuclear emission. (2) We propose new experimental tests of the BEC mechanism by measuring the pressure and temperature dependence of LENR events using deuterium gas and these deuterated metals with or without Li. If the LENRTPCM are surface phenomena, the proposed use of micro-/nano-scale porous materials is expected to enhance and scale up the LENRTPCM effects by many order of magnitude, and thus may lead to better reproductivity and theoretical understanding of the phenomena.

The architecture of ArgR-DNA complexes at the genome-scale in Escherichia coli

DEFF Research Database (Denmark)

Cho, Suhyung; Cho, Yoo-Bok; Kang, Taek Jin

2015-01-01

DNA-binding motifs that are recognized by transcription factors (TFs) have been well studied; however, challenges remain in determining the in vivo architecture of TF-DNA complexes on a genome-scale. Here, we determined the in vivo architecture of Escherichia coli arginine repressor (ArgR)-DNA co...

Reverse micelle-loaded lipid nano-emulsions: new technology for nano-encapsulation of hydrophilic materials.

Science.gov (United States)

Anton, Nicolas; Mojzisova, Halina; Porcher, Emilien; Benoit, Jean-Pierre; Saulnier, Patrick

2010-10-15

This study presents novel, recently patented technology for encapsulating hydrophilic species in lipid nano-emulsions. The method is based on the phase-inversion temperature method (the so-called PIT method), which follows a low-energy and solvent-free process. The nano-emulsions formed are stable for months, and exhibit droplet sizes ranging from 10 to 200 nm. Hydrophilic model molecules of fluorescein sodium salt are encapsulated in the oily core of these nano-emulsion droplets through their solubilisation in the reverse micellar system. As a result, original, multi-scaled nano-objects are generated with a 'hydrophilic molecule in a reverse-micelles-in-oil-in-water' structure. Once fluorescein has been encapsulated it remains stable, for thermodynamic reasons, and the encapsulation yields can reach 90%. The reason why such complex objects can be formed is due to the soft method used (PIT method) which allows the conservation of the structure of the reverse micelles throughout the formulation process, up to their entrapment in the nano-emulsion droplets. In this study, we focus the investigation on the process itself, revealing its potential and limits. Since the formulation of nanocarriers for the encapsulation of hydrophilic substances still remains a challenge, this study may constitute a significant advance in this field. Copyright 2010 Elsevier B.V. All rights reserved.

Nano Materials

International Nuclear Information System (INIS)

Jin, In Ju; Lee, Ik Mo; Kwon, Yeung Gu

2006-02-01

This book introduces background of nano science such as summary, plenty room at the bottom, access way to nano technique, nanoparticles using bottom-up method which are a marvel of nature, and modern alchemy : chemical synthesis of artificial nano structure, understanding of quantum mechanics, STM/AFM, nano metal powder, ceramic nanoparticles, nano structure film, manufacture of nanoparticles using reverse micelle method, carbon nano tube, sol-gel material, nano energy material, nano catalyst nano bio material technology and spintronics.

Dancing to CHANGA: a self-consistent prediction for close SMBH pair formation time-scales following galaxy mergers

Science.gov (United States)

Tremmel, M.; Governato, F.; Volonteri, M.; Quinn, T. R.; Pontzen, A.

2018-04-01

We present the first self-consistent prediction for the distribution of formation time-scales for close supermassive black hole (SMBH) pairs following galaxy mergers. Using ROMULUS25, the first large-scale cosmological simulation to accurately track the orbital evolution of SMBHs within their host galaxies down to sub-kpc scales, we predict an average formation rate density of close SMBH pairs of 0.013 cMpc-3 Gyr-1. We find that it is relatively rare for galaxy mergers to result in the formation of close SMBH pairs with sub-kpc separation and those that do form are often the result of Gyr of orbital evolution following the galaxy merger. The likelihood and time-scale to form a close SMBH pair depends strongly on the mass ratio of the merging galaxies, as well as the presence of dense stellar cores. Low stellar mass ratio mergers with galaxies that lack a dense stellar core are more likely to become tidally disrupted and deposit their SMBH at large radii without any stellar core to aid in their orbital decay, resulting in a population of long-lived `wandering' SMBHs. Conversely, SMBHs in galaxies that remain embedded within a stellar core form close pairs in much shorter time-scales on average. This time-scale is a crucial, though often ignored or very simplified, ingredient to models predicting SMBH mergers rates and the connection between SMBH and star formation activity.

Nano-technology and nano-toxicology

OpenAIRE

Maynard, Robert L.

2012-01-01

Rapid developments in nano-technology are likely to confer significant benefits on mankind. But, as with perhaps all new technologies, these benefits are likely to be accompanied by risks, perhaps by new risks. Nano-toxicology is developing in parallel with nano-technology and seeks to define the hazards and risks associated with nano-materials: only when risks have been identified they can be controlled. This article discusses the reasons for concern about the potential effects on health of ...

High performance nano-composite technology development

Energy Technology Data Exchange (ETDEWEB)

Kim, Whung Whoe; Rhee, C. K.; Kim, S. J.; Park, S. D. [KAERI, Taejon (Korea, Republic of); Kim, E. K.; Jung, S. Y.; Ryu, H. J. [KRICT, Taejon (Korea, Republic of); Hwang, S. S.; Kim, J. K.; Hong, S. M. [KIST, Taejon (Korea, Republic of); Chea, Y. B. [KIGAM, Taejon (Korea, Republic of); Choi, C. H.; Kim, S. D. [ATS, Taejon (Korea, Republic of); Cho, B. G.; Lee, S. H. [HGREC, Taejon (Korea, Republic of)

1999-06-15

The trend of new material development are being to carried out not only high performance but also environmental attraction. Especially nano composite material which enhances the functional properties of components, extending the component life resulting to reduced the wastes and environmental contamination, has a great effect on various industrial area. The application of nano composite, depends on the polymer matrix and filler materials, has various application from semiconductor to medical field. In spite of nano composite merits, nano composite study are confined to a few special materials as a lab, scale because a few technical difficulties are still on hold. Therefore, the purpose of this study establishes the systematical planning to carried out the next generation projects on order to compete with other countries and overcome the protective policy of advanced countries with grasping over sea's development trends and our present status. (author).

Micro/Nano manufacturing

DEFF Research Database (Denmark)

Tosello, Guido

2017-01-01

Micro- and nano-scale manufacturing has been the subject of an increasing amount of interest and research effort worldwide in both academia and industry over the past 10 years.Traditional (MEMS) manufacturing, but also precision manufacturing technologies have been developed to cover micro......-scale dimensions and accuracies. Furthermore, these fundamentally different technology ecosystems are currently combined in order to exploit strengths of both platforms. One example is the use of lithography-based technologies to establish nanostructures that are subsequently transferred to 3D geometries via...

SKYLARK - A crossbow-launched micro scale cheap UAV for close aerial surveillance

OpenAIRE

Alexandru-Marius PANAIT

2012-01-01

Close air support of ground troops especially in densely populated, urban environments has an ever increasing prevalence in the modern warfare. Counter-terrorism activities as well as land-based “surgical strikes” impose a set of special requirements on all the used weapons and equipment so as to minimize weight, cost and complexity and maximize efficiency. Small scale UAVs are in service with all the armed forces around the globe; micro UAVs are emerging as the ground troop close support pre...

From Nano Structure to Systems: Fabrication and Characterization

International Nuclear Information System (INIS)

Uda Hashim

2011-01-01

NPD is designed in various nano wires scale size from 100 nm down to 20 nm. Next, the nano fabrication process flow development which consists of the detailed parameters and recipes are developed for nano wires formation. In order to produce very small nano wires, the dimensions, developments, etch profiles of nano wires and size reduction by thermal oxidation was investigated. Finally, the combination on top-down nano fabrication method and size-reduction has resulted in successful reduction of Nano wires reduced from 100 nm to approximately 20 nm. Spacer Patterning Lithography (SPL) is another technique used to fabricate nano structure especially nano wire. It is a low-cost and compatible to standard CMOS fabrication process. SPL, in general is a combination of conventional photolithography, anisotropic etchings and the excellent homogeneity and reproducibility of conformal chemical vapor deposition processes. The detail process flow involving every step in SPL including the deposition of a sacrificial layer, the definition of vertical step by means of lithography and etch-back process, the deposition of a conformal layer, final anisotropic etching and formation of gold pad. A wire with the scale in nano size has a wide range of applications. Up to present, the nano wires have been implemented in electronics, optics, mechanics, and sensing technology etc. One of the fields where nano wires have been used as building blocks is biosensor. Biosensor has been developed for different applications such as health care, industrial process control, environmental monitoring, quality control of food applications etc. Nevertheless, the conventional biosensor has its disadvantages, which are expensive, time-consuming, and require highly trained personnel. Therefore, there is increasing interest in the development of new type of biosensor which has the advantages of label-free, ultrasensitive, and near real-time operation. (author)

Multi-scale coding of genomic information: From DNA sequence to genome structure and function

International Nuclear Information System (INIS)

Arneodo, Alain; Vaillant, Cedric; Audit, Benjamin; Argoul, Francoise; D'Aubenton-Carafa, Yves; Thermes, Claude

2011-01-01

Understanding how chromatin is spatially and dynamically organized in the nucleus of eukaryotic cells and how this affects genome functions is one of the main challenges of cell biology. Since the different orders of packaging in the hierarchical organization of DNA condition the accessibility of DNA sequence elements to trans-acting factors that control the transcription and replication processes, there is actually a wealth of structural and dynamical information to learn in the primary DNA sequence. In this review, we show that when using concepts, methodologies, numerical and experimental techniques coming from statistical mechanics and nonlinear physics combined with wavelet-based multi-scale signal processing, we are able to decipher the multi-scale sequence encoding of chromatin condensation-decondensation mechanisms that play a fundamental role in regulating many molecular processes involved in nuclear functions.

Nano crystals-Related Synthesis, Assembly, and Energy Applications

International Nuclear Information System (INIS)

Dai, Q.; Hu, M.Z.; Yu, B.Z.; William, W.; Seo, J.

2011-01-01

Fundamental material properties have been dramatically altered in the nano scale regime because of quantum confinement effect. The unique size-tunable functionalities of nano materials make them involved in an extensive variety of energy applications, such as light-emitting diodes and solar cells. These applications have been demonstrated to cut energy consumption. In response to the ever-growing energy demands as well as the concerns of global warming, researchers are actively placing their enormous emphasis on the exploration of energy savings. During this exploration, the primary stage requires the design of appropriate strategies for the synthesis of high-quality nano crystals in terms of size uniformity and superior optical/electronic properties. Especially, there is a need to seek green-chemistry approaches for the synthesis of environmentally benign and user-friendly nano crystals. Another recent area of focus is the use of individual nano crystals as building blocks for self-assembly, providing new opportunities to improve the nano crystal performance

Modeling and Design of a Nano Scale CMOS Inverter for Symmetric Switching Characteristics

Directory of Open Access Journals (Sweden)

Joyjit Mukhopadhyay

2012-01-01

Full Text Available This paper presents a technique for the modeling and design of a nano scale CMOS inverter circuit using artificial neural network and particle swarm optimization algorithm such that the switching characteristics of the circuit is symmetric, that is, has nearly equal rise and fall time and equal output high-to-low and low-to-high propagation delay. The channel width of the transistors and the load capacitor value are taken as design parameters. The designed circuit has been implemented at the transistor-level and simulated using TSPICE for 45 nm process technology. The PSO-generated results have been compared with SPICE results. A very good accuracy has been achieved. In addition, the advantage of the present approach over an existing approach for the same purpose has been demonstrated through simulation results.

Fabrication and Characterization of Polymeric Hollow Fiber Membranes with Nano-scale Pore Sizes

International Nuclear Information System (INIS)

Amir Mansourizadeh; Ahmad Fauzi Ismail

2011-01-01

Porous polyvinylidene fluoride (PVDF) and polysulfide (PSF) hollow fiber membranes were fabricated via a wet spinning method. The membranes were characterized in terms of gas permeability, wetting pressure, overall porosity and water contact angle. The morphology of the membranes was examined by FESEM. From gas permeation test, mean pore sizes of 7.3 and 9.6 nm were obtained for PSF and PVDF membrane, respectively. Using low polymer concentration in the dopes, the membranes demonstrated a relatively high overall porosity of 77 %. From FESEM examination, the PSF membrane presented a denser outer skin layer, which resulted in significantly lower N 2 permeance. Therefore, due to the high hydrophobicity and nano-scale pore sizes of the PVDF membrane, a good wetting pressure of 4.5x10 -5 Pa was achieved. (author)

Nano technologies, technologies converging and potential biomedical applications

International Nuclear Information System (INIS)

Capuano, V.

2005-01-01

The applications of nano technology to biology and medicine appear really promising for diagnostics, for various therapeutic approaches and in medical instrumentations. The growing synergism among nano technology, biotechnology, information technology and cognitive sciences, their convergence (NBIC) from the nano scale, could involve on next decades great changes in medicine, from a reactive to a predictive and preventive approach. It is expected that NBIC converging technologies could achieve tremendous improvements in human abilities and enhance societal achievement of related social and ethical implications, in the framework of a constant dialogue between science and society [it

Distribution of distances between DNA barcode labels in nanochannels close to the persistence length

Science.gov (United States)

Reinhart, Wesley F.; Reifenberger, Jeff G.; Gupta, Damini; Muralidhar, Abhiram; Sheats, Julian; Cao, Han; Dorfman, Kevin D.

2015-02-01

We obtained experimental extension data for barcoded E. coli genomic DNA molecules confined in nanochannels from 40 nm to 51 nm in width. The resulting data set consists of 1 627 779 measurements of the distance between fluorescent probes on 25 407 individual molecules. The probability density for the extension between labels is negatively skewed, and the magnitude of the skewness is relatively insensitive to the distance between labels. The two Odijk theories for DNA confinement bracket the mean extension and its variance, consistent with the scaling arguments underlying the theories. We also find that a harmonic approximation to the free energy, obtained directly from the probability density for the distance between barcode labels, leads to substantial quantitative error in the variance of the extension data. These results suggest that a theory for DNA confinement in such channels must account for the anharmonic nature of the free energy as a function of chain extension.

Nano-Scale Devices for Frequency-Based Magnetic Biosensing

Science.gov (United States)

2017-01-31

show the basic measurement setup (the field is applied perpendicular to the disk plane). A radiofrequency signal is injected across the disk (disks...shown in Fig. 7(a). A spectrum analyser (S.A.) (or a high frequency oscilloscope) is used to measure the radiofrequency STO output signal with Fig...crystals and, via electrical measurements , in magnetic-vortex-containing, isolated micro- and nano-devices. Via micromagnetic simulations, we have largely

Carbon nano tubes embedded in polymer nano fibers

International Nuclear Information System (INIS)

Dror, Y.; Kedem, S.; Khalfin, R.L.; Paz, Y.; Cohenl, Y.; Salalha, Y.; Yarin, A.L.; Zussman, A.

2004-01-01

Full Text: The electro spinning process was used successfully to embed Multi-walled carbon nano tubes (MWCNTs) and single-walled carbon nano tubes (SWCNTs) in a matrix of poly(ethylene oxide) (PEO) forming composite nano fibers. Initial dispersion of SWCNTs in water was achieved by the use of an amphphilic alternating copolymer of styrene and sodium maleate. MWNT dispersion was achieved by ionic and nonionic surfactants. The distribution and conformation of the nano tubes in the nano fibers were studied by transmission electron microscopy (TEM). Oxygen plasma etching was used to expose the nano tubes within the nano fibers to facilitate direct observation. Nano tube alignment within the nano fibers was shown to depend strongly on the quality of the initial dispersions. Well-dispersed and separated nano tubes were embedded in a straight and aligned form while entangled non-separated nano tubes were incorporated as dense aggregates. X-ray diffraction demonstrated a high degree of orientation of the PEO crystals in the electro spun nano fibers with embedded SWCNTs, whereas incorporation of MVCNTs had a detrimental effect on the polymer orientation. Composite polymer nano fibers containing dispersed phases of nanometric TiO 2 particles and MWCNTs were also prepared electro spinning. In this case, the polymer matrix was poly(acrylonitrile) (PAN). The morphology and possible applications of these composite nano fibers will be discussed

Engineered nano particles: Nature, behavior, and effect on the environment.

Science.gov (United States)

Goswami, Linee; Kim, Ki-Hyun; Deep, Akash; Das, Pallabi; Bhattacharya, Satya Sundar; Kumar, Sandeep; Adelodun, Adedeji A

2017-07-01

Increased application of engineered nano particles (ENPs) in production of various appliances and consumer items is increasing their presence in the natural environment. Although a wide variety of nano particles (NPs) are ubiquitously dispersed in ecosystems, risk assessment guidelines to describe their ageing, direct exposure, and long-term accumulation characteristics are poorly developed. In this review, we describe what is known about the life cycle of ENPs and their impact on natural systems and examine if there is a cohesive relationship between their transformation processes and bio-accessibility in various food chains. Different environmental stressors influence the fate of these particles in the environment. Composition of solid media, pore size, solution chemistry, mineral composition, presence of natural organic matter, and fluid velocity are some environmental stressors that influence the transformation, transport, and mobility of nano particles. Transformed nano particles can reduce cell viability, growth and morphology, enhance oxidative stress, and damage DNA in living organisms. Copyright © 2017 Elsevier Ltd. All rights reserved.

Nano lab-on-chip systems for biomedical and environmental ...

African Journals Online (AJOL)

In recent years, nano lab-on-chip (NLOC) has emerged as a powerful tool for biosensing and an active area of research particularly in DNA genetic and genetic related investigations. Compared with conventional sensing techniques, distinctive advantages of using NLOC for biomedicine and other related area include ...

DNA-FET using carbon nanotube electrodes

International Nuclear Information System (INIS)

Sasaki, T K; Ikegami, A; Aoki, N; Ochiai, Y

2006-01-01

We demonstrate DNA field effect transistor (DNA-FET) using multiwalled carbon nanotube (MWNT) as nano-structural source and drain electrodes. The MWNT electrodes have been fabricated by focused ion-beam bombardment (FIBB). A very short channel, approximately 50 nm, was easily formed between the severed MWNT. The current-voltage (I-V) characteristics of DNA molecules between the MWNT electrodes showed hopping transport property. We have also measured the gate-voltage dependence in the I-V characteristics and found that poly DNA molecules exhibits p-type conduction. The transport of DNA-FET can be explained by two hopping lengths which depend on the range of the source-drain bias voltages

Synthesis of nano-textured biocompatible scaffolds from chicken eggshells

International Nuclear Information System (INIS)

Asghar, Waseem; Ilyas, Azhar; Sankaran, Jeyantt; Wan Yuan; Iqbal, Samir M; Kim, Young-Tae

2012-01-01

Cell adhesion, morphology and growth are influenced by surface topography at nano and micrometer scales. Nano-textured surfaces are prepared using photolithography, plasma etching and long polymer chemical etching which are cost prohibitive and require specialized equipment. This article demonstrates a simple approach to synthesize nano-textured scaffolds from chicken eggshells. Varieties of pattern are made on the eggshells like micro-needle forests and nanopores, giving very uniform nano-textures to the surfaces. The surfaces are characterized for chemical composition and crystal phase. The novel patterns are transferred to PDMS surfaces and the nano-textured PDMS surfaces are used to study the effect of texturing on human fibroblast cell growth and attachment. The effects of surface topographies, along with laminin coating on cell cultures, are also studied. We find an exciting phenomenon that the initial seeding density of the fibroblast cells affects the influence of the nano-texturing on cell growth. These nano-textured surfaces give 16 times more fibroblast growth when compared to flat PDMS surfaces. The novel nano-textured patterns also double the laminin adsorption on PDMS. (paper)

Validation of the Scale of Preferences and Expectations in Close Interpersonal Relationships (EPERIC).

Science.gov (United States)

Fontanil, Yolanda; Ezama, Esteban; Alonso, Yolanda

2013-01-01

The most commonly used instruments for assessing adult attachment have shown differing combinations of items and divergences in the resulting sub-scales. This study presents the Scale of Preferences and Expectations in Close Interpersonal Relationships ( Escala de Preferencias y Expectativas en las Relaciones Interpersonales Cercanas, EPERIC), made up of 22 items, and based upon the Relationship Scales Questionnaire (RSQ) of Griffin and Bartholomew. Exploratory and confirmatory factorial analyses (EFA and CFA) were undertaken using data from a sample of 594 people. Factor analysis distinguishes three sub-scales: Fear of rejection or abandonment , Desire for closeness and Preference for independence , which explains 42.78% of the total variance. The alpha coefficients reveal a high internal consistency of the instrument and its sub-scales. Regarding validity, CFA showed an adequate fit for the trifactorial solution, and the expected correlations with other instruments for assessing attachment style in adults were found. EPERIC is also suitable for predicting affective states and psychological well-being. The EPERIC is a potentially useful and valid instrument for research and clinical purposes. The discussion focuses on the fact that our results support a model of three factors rather than two, as is usual in studies on adult attachment.

Pinning in high performance MgB{sub 2} thin films and bulks: Role of Mg-B-O nano-scale inhomogeneities

Energy Technology Data Exchange (ETDEWEB)

Prikhna, Tatiana, E-mail: prikhna@mail.ru [Institute for Superhard Materials of the National Academy of Sciences of Ukraine , 2, Avtozavodskaya Str. , Kiev 07074 (Ukraine); Shapovalov, Andrey [Institute for Superhard Materials of the National Academy of Sciences of Ukraine , 2, Avtozavodskaya Str. , Kiev 07074 (Ukraine); Eisterer, Michael [Atominstitut, Vienna University of Technology, Stadionallee 2, 1020 Vienna (Austria); Shaternik, Vladimir [G.V. Kurdyumov Institute for Metal Physics of the National Academy of Sciences of Ukraine, 36 Academician Vernadsky blvd., Kiev, 03680 (Ukraine); Goldacker, Wilfried [Karlsruhe Institute of Technology (KIT), 76344 Eggenstein (Germany); Weber, Harald W. [Atominstitut, Vienna University of Technology, Stadionallee 2, 1020 Vienna (Austria); Moshchil, Viktor; Kozyrev, Artem; Sverdun, Vladimir [Institute for Superhard Materials of the National Academy of Sciences of Ukraine , 2, Avtozavodskaya Str. , Kiev 07074 (Ukraine); Boutko, Viktor [Donetsk Institute for Physics and Engineering named after O.O. Galkin of the National Academy of Sciences of Ukraine, R. Luxemburg str.72, Donetsk-114, 83114 (Ukraine); Grechnev, Gennadiy [B. Verkin Institute for Low Temperature Physics of the National Academy of Sciences of Ukraine, 47, Prospekt Nauky, Kharkiv 61103 (Ukraine); Gusev, Alexandr [Donetsk Institute for Physics and Engineering named after O.O. Galkin of the National Academy of Sciences of Ukraine, R. Luxemburg str.72, Donetsk-114, 83114 (Ukraine); Kovylaev, Valeriy; Shaternik, Anton [Institute for Superhard Materials of the National Academy of Sciences of Ukraine , 2, Avtozavodskaya Str. , Kiev 07074 (Ukraine)

2017-02-15

Highlights: • Pinning in MgB{sub 2} depends on the Mg-B-O nano-scaled inhomogeneities. • Finer oxygen-enriched inhomogeneities is the reason of the higher J{sub c} in MgB{sub 2} thin films as compared to bulk. • The results of DOS calculations for MgB{sub 2-x}O{sub x} compounds demonstrate that they have metal-like behavior. • Ordered oxygen distribution in MgB{sub 2} (in pairs or zigzags) reduces binding energy. - Abstract: The comparison of nano-crystalline MgB{sub 2} oxygen-containing thin film (140 nm) and highly dense bulk materials showed that the critical current density, J{sub c}, depends on the distribution of Mg-B-O nano-scale inhomogeneities. It has been shown that MgB{sub 2} bulks with high J{sub c} in low (∼10{sup 6} A/cm{sup 2} in 0-1 T at 10 K) and medium magnetic fields contain MgB{sub 0.6-0.8}O{sub 0.8-0.9} nano-inclusions, where δT{sub c} or a combined δT{sub c} (dominant) / δ{sub l} pinning mechanism prevails, while in bulk MgB{sub 2} with high J{sub c} in high magnetic fields (B{sub irr}(18.5 K) = 15 T, B{sub c2}(0 K) = 42.1 T) MgB{sub 1.2-2.7}O{sub 1.8-2.5} nano-layers are present and δ{sub l} pinning prevails. The structure of oxygen-containing films with high J{sub c} in low and high magnetic fields (J{sub c} (0 T) = 1.8 × 10{sup 7} A/cm{sup 2} and J{sub c} (5 T) = 2 × 10{sup 6} A/cm{sup 2} at 10 K) contains very fine oxygen-enriched Mg-B-O inhomogeneities and δ{sub l} pinning is realized. The results of DOS calculations in MgB{sub 2-x}O{sub x} cells for x = 0, 0.125, 0.25, 0.5, 1 demonstrate that all compounds are conductors with metal-like behaviour. In the case of ordered oxygen substitution for boron the binding energy, E{sub b}, does not increase sufficiently as compared with that for MgB{sub 2}, while when oxygen atoms form zigzag chains the calculated E{sub b} is even lower (E{sub b} = −1.15712 Ry).

Time-Dependent Measure of a Nano-Scale Force-Pulse Driven by the Axonemal Dynein Motors in Individual Live Sperm Cells

Energy Technology Data Exchange (ETDEWEB)

Allen, M J; Rudd, R E; McElfresh, M W; Balhorn, R

2009-04-23

Nano-scale mechanical forces generated by motor proteins are crucial to normal cellular and organismal functioning. The ability to measure and exploit such forces would be important to developing motile biomimetic nanodevices powered by biological motors for Nanomedicine. Axonemal dynein motors positioned inside the sperm flagellum drive microtubule sliding giving rise to rhythmic beating of the flagellum. This force-generating action makes it possible for the sperm cell to move through viscous media. Here we report new nano-scale information on how the propulsive force is generated by the sperm flagellum and how this force varies over time. Single cell recordings reveal discrete {approx}50 ms pulses oscillating with amplitude 9.8 {+-} 2.6 nN independent of pulse frequency (3.5-19.5 Hz). The average work carried out by each cell is 4.6 x 10{sup -16} J per pulse, equivalent to the hydrolysis of {approx}5,500 ATP molecules. The mechanochemical coupling at each active dynein head is {approx}2.2 pN/ATP, and {approx}3.9 pN per dynein arm, in agreement with previously published values obtained using different methods.

A capability study of micro moulding for nano fluidic system manufacture

DEFF Research Database (Denmark)

Calaon, Matteo; Hansen, Hans Nørgaard; Tosello, Guido

2013-01-01

With the present paper the authors analysed process capability of ultra-precision moulding used for producing nano crosses with the same critical channels dimensions of a nano fluidic system for optical mapping of genomic length DNA. The process variation focused on product tolerances is quantified...... through AFM measurements. Uncertainty assessment of measurements on polymer objects is described and quality control results of sub-micro injection moulded crosses are shown in respect of the tolerance range specified by the end user as limit value for functional design....

The growth of noble metals in (112-bar0)-oriented hexagonal close-packed nano-films by epitaxy on Nb(001)

International Nuclear Information System (INIS)

Hueger, E.; Osuch, K.

2005-01-01

The morphology and crystal structure of noble metal nano-films deposited on oxygen contaminated and oxygen-free Nb(001) surfaces have been studied with angle-resolved ultraviolet photoelectron spectroscopy, X-ray photo-electron diffraction, and reflection high energy electron diffraction. In the both cases a deposited noble metal film aligns its direction with the [110] direction of the Nb(001) surface. But, while a noble metal grows on an oxygen contaminated Nb(001) surface with the hexagonal close-packed (hcp) (111) planes parallel to the surface (i.e. in the (111)-oriented face centred cubic phase (fcc)), on a non-contaminated Nb(001) it grows with its hcp planes perpendicular to the surface. The latter happens because in the initial stages of the epitaxy the first two monolayers (MLs) of the noble metal grow pseudomorphically on a contamination-free Nb(001). The pseudomorphic layer is strongly extended parallel to the Nb(001) surface in comparison to its natural fcc (001) plane. As a consequence of the atomic volume conservation principle the out-of-plane lattice of the pseudomorphic layer is contracted. Thus, its body centred tetragonal (110) planes, which stay perpendicular to the surface, contract into denser-packed planes, i.e. in hcp ones. In the direction perpendicular to the surface, where the substrate does not have a direct influence on the film, the pseudomorphic layer relaxes into its natural close-packed phase, i.e. into hcp atomic planes. These planes appear as soon as the third pseudomorphic ML begins to grow. The stacking axis of the planes lies in the (100) surface of Nb and is locked by it. The fact that thick nano-films of Cu (up to 50 MLs), Ag and Au (up to 100 MLs) grow in the (112-bar0)-oriented hcp phase can be attributed to a much better fit of the hcp than of fcc stacking sequence to the four-fold symmetry of the Nb(001) surface

Toward efficient modification of large gold nanoparticles with DNA

NARCIS (Netherlands)

Gill, R.; Göeken, Kristian L; Subramaniam, V.

2014-01-01

DNA-coated gold nanoparticles are one of the most researched nano-bio hybrid systems. Traditionally their synthesis has been a long and tedious process, involving slow salt addition and long incubation steps. This stems from the fact that both DNA and gold particles are negatively charged, therefore

Proposal for new experimental tests of the Bose-Einstein condensation mechanism for low-energy nuclear reaction and transmutation processes in deuterium loaded micro- and nano-scale cavities

International Nuclear Information System (INIS)

Yeong, E. Kim; Koltick, David S.; Reifenberger, Ronald G.; Zubarev, Alexander L.

2006-01-01

Most of experimental results of low-energy nuclear reaction (LENR) reported so far cannot be reproduced on demand. There have been persistent. experimental results indicating that the LENR und transmutation processes in condensed matter (LENRTPCM) are surface phenomena rather than bulk phenomena. Recently, proposed Bose-Einstein condensation (BEC) mechanism may provide a suitable theoretical description of the surface phenomena. New experiments are proposed and described for testing the BEC mechanism for LENR and transmutation processes in micro- and nano-scale traps. (1) We propose the use of micro-or nano-porous conducting materials as a cathode in electrolysis experiments with heavy water with or without Li in order to stabilize the active surface spots and to enhance the effect for the purpose of improving the reproducibility of excess heat generation and nuclear emission. (2) We propose new experimental tests of the BEC mechanism by measuring the pressure and temperature dependence of LENR events using deuterium gas and those deuterated metals with or without Li. If the LENRTPCM are surface phenomena, the proposed use of micro-/nano-scale porous materials is expected to enhance and scale up the LENRTPCM effects by many orders of magnitude, and thus may lead to better reproducibility and theoretical understanding of the phenomena. (authors)

Proposal for new experimental tests of the Bose-Einstein condensation mechanism for low-energy nuclear reaction and transmutation processes in deuterium loaded micro- and nano-scale cavities

Energy Technology Data Exchange (ETDEWEB)

Yeong, E. Kim; Koltick, David S.; Reifenberger, Ronald G.; Zubarev, Alexander L. [Department of Phsysics, Purdue University, West Lafayette, IN 47907 (United States)

2006-07-01

Most of experimental results of low-energy nuclear reaction (LENR) reported so far cannot be reproduced on demand. There have been persistent. experimental results indicating that the LENR und transmutation processes in condensed matter (LENRTPCM) are surface phenomena rather than bulk phenomena. Recently, proposed Bose-Einstein condensation (BEC) mechanism may provide a suitable theoretical description of the surface phenomena. New experiments are proposed and described for testing the BEC mechanism for LENR and transmutation processes in micro- and nano-scale traps. (1) We propose the use of micro-or nano-porous conducting materials as a cathode in electrolysis experiments with heavy water with or without Li in order to stabilize the active surface spots and to enhance the effect for the purpose of improving the reproducibility of excess heat generation and nuclear emission. (2) We propose new experimental tests of the BEC mechanism by measuring the pressure and temperature dependence of LENR events using deuterium gas and those deuterated metals with or without Li. If the LENRTPCM are surface phenomena, the proposed use of micro-/nano-scale porous materials is expected to enhance and scale up the LENRTPCM effects by many orders of magnitude, and thus may lead to better reproducibility and theoretical understanding of the phenomena. (authors)

Large-scale preparation of plasmid DNA.

Science.gov (United States)

Heilig, J S; Elbing, K L; Brent, R

2001-05-01

Although the need for large quantities of plasmid DNA has diminished as techniques for manipulating small quantities of DNA have improved, occasionally large amounts of high-quality plasmid DNA are desired. This unit describes the preparation of milligram quantities of highly purified plasmid DNA. The first part of the unit describes three methods for preparing crude lysates enriched in plasmid DNA from bacterial cells grown in liquid culture: alkaline lysis, boiling, and Triton lysis. The second part describes four methods for purifying plasmid DNA in such lysates away from contaminating RNA and protein: CsCl/ethidium bromide density gradient centrifugation, polyethylene glycol (PEG) precipitation, anion-exchange chromatography, and size-exclusion chromatography.

MICRO & NANO TECHNOLOGIES – APPLICATIONS, DESIGN AND INTEGRATION

Directory of Open Access Journals (Sweden)

Dorin LEŢ

2010-05-01

Full Text Available The science of micro-nano technologies represents a multidisciplinary research domain, which provokes active participation of specialist from multiple domains (physics, chemistry, biology, mathematics, electronics, medicine, a.o.. Nanotechnology is an applied science domain focusing the design, synthesis and characterization of materials and devices starting from individual atoms and molecules level up to supramolecular level of strains of molecules with 100 molecular diameters. Operations at this dimensions implies the understanding of new scientific principles and new materials properties, which take place at micro and nano scale and are used in the development of materials, devices and systems with new and improved functions and performances. The properties and basic functions of structures and material systems at nano scale may be changed based on the organization of the living mater on molecular “weak” interactions (hydrogen binds, electrostatic dipole, Van der Waals forces, surface forces, electrofluidic forces, a.o..

Phylogenetic reconstruction and DNA barcoding for closely related pine moth species (Dendrolimus) in China with multiple gene markers.

Science.gov (United States)

Dai, Qing-Yan; Gao, Qiang; Wu, Chun-Sheng; Chesters, Douglas; Zhu, Chao-Dong; Zhang, Ai-Bing

2012-01-01

Unlike distinct species, closely related species offer a great challenge for phylogeny reconstruction and species identification with DNA barcoding due to their often overlapping genetic variation. We tested a sibling species group of pine moth pests in China with a standard cytochrome c oxidase subunit I (COI) gene and two alternative internal transcribed spacer (ITS) genes (ITS1 and ITS2). Five different phylogenetic/DNA barcoding analysis methods (Maximum likelihood (ML)/Neighbor-joining (NJ), "best close match" (BCM), Minimum distance (MD), and BP-based method (BP)), representing commonly used methodology (tree-based and non-tree based) in the field, were applied to both single-gene and multiple-gene analyses. Our results demonstrated clear reciprocal species monophyly for three relatively distant related species, Dendrolimus superans, D. houi, D. kikuchii, as recovered by both single and multiple genes while the phylogenetic relationship of three closely related species, D. punctatus, D. tabulaeformis, D. spectabilis, could not be resolved with the traditional tree-building methods. Additionally, we find the standard COI barcode outperforms two nuclear ITS genes, whatever the methods used. On average, the COI barcode achieved a success rate of 94.10-97.40%, while ITS1 and ITS2 obtained a success rate of 64.70-81.60%, indicating ITS genes are less suitable for species identification in this case. We propose the use of an overall success rate of species identification that takes both sequencing success and assignation success into account, since species identification success rates with multiple-gene barcoding system were generally overestimated, especially by tree-based methods, where only successfully sequenced DNA sequences were used to construct a phylogenetic tree. Non-tree based methods, such as MD, BCM, and BP approaches, presented advantages over tree-based methods by reporting the overall success rates with statistical significance. In addition, our

Phylogenetic reconstruction and DNA barcoding for closely related pine moth species (Dendrolimus in China with multiple gene markers.

Directory of Open Access Journals (Sweden)

Qing-Yan Dai

Full Text Available Unlike distinct species, closely related species offer a great challenge for phylogeny reconstruction and species identification with DNA barcoding due to their often overlapping genetic variation. We tested a sibling species group of pine moth pests in China with a standard cytochrome c oxidase subunit I (COI gene and two alternative internal transcribed spacer (ITS genes (ITS1 and ITS2. Five different phylogenetic/DNA barcoding analysis methods (Maximum likelihood (ML/Neighbor-joining (NJ, "best close match" (BCM, Minimum distance (MD, and BP-based method (BP, representing commonly used methodology (tree-based and non-tree based in the field, were applied to both single-gene and multiple-gene analyses. Our results demonstrated clear reciprocal species monophyly for three relatively distant related species, Dendrolimus superans, D. houi, D. kikuchii, as recovered by both single and multiple genes while the phylogenetic relationship of three closely related species, D. punctatus, D. tabulaeformis, D. spectabilis, could not be resolved with the traditional tree-building methods. Additionally, we find the standard COI barcode outperforms two nuclear ITS genes, whatever the methods used. On average, the COI barcode achieved a success rate of 94.10-97.40%, while ITS1 and ITS2 obtained a success rate of 64.70-81.60%, indicating ITS genes are less suitable for species identification in this case. We propose the use of an overall success rate of species identification that takes both sequencing success and assignation success into account, since species identification success rates with multiple-gene barcoding system were generally overestimated, especially by tree-based methods, where only successfully sequenced DNA sequences were used to construct a phylogenetic tree. Non-tree based methods, such as MD, BCM, and BP approaches, presented advantages over tree-based methods by reporting the overall success rates with statistical significance. In

Ultrasonic-assisted synthesis of nano lead(II) coordination polymer as precursors for preparation of lead(II) oxide nano-structures: Thermal, optical properties and XRD studies.

Science.gov (United States)

Ghavidelaghdam, Elham; Shahverdizadeh, Gholam Hossein; Motameni Tabatabai, Javad; Mirtamizdoust, Babak

2018-04-01

Nano structure of a lead (II) coordination polymer [Pb 2 (C 2 Cl 3 O 2 ) 2 (NO 3 ) 2 (C l2 H 8 N 2 ) 2 ] n (1), has been synthesized by a sonochemical method in different concentrations. The nano particles were characterized by scanning electron microscopy (SEM) X-ray powder diffraction (XRD), FT-IR spectroscopy and elemental analyses. The thermal stability of nano structure is closely investigated via thermal gravimetric (TGA), and compared with crystalline structure. The compounds are then heated to 600 °C to produce PbO nano particles. The resulting PbO is characterized through XRD and SEM analyses. Concentration of initial reagents effects on size and morphology of nano-structured compound 1 have been studied and show that low concentrations of initial reagents decreased particles size and leaded to uniform nano particles morphology. The photoluminescence properties of the prepared compound, as crystalline and as nanoparticles, have been investigated. The result showed a good correlation between the size and emission wavelength. Copyright © 2017. Published by Elsevier B.V.

Toxic effects and bioaccumulation of nano-, micron-, and ionic-Ag on the polychaete, Nereis diversicolor

DEFF Research Database (Denmark)

Cong, Yi; Banta, Gary Thomas; Selck, Henriette

2011-01-01

There is increasing concern about the toxicities and potential risks, both still poorly understood, of silver nanoparticles for the aquatic environment after their eventual release via wastewater discharges. In this study, the toxicities of sediment associated nano (...)- and ionic (AgNO3)- Ag on the sediment-dwelling polychaete, Nereis diversicolor, were compared after 10 days of sediment exposure, using survival, DNA damage (comet assay) and bioaccumulation as endpoints. The nominal concentrations used in all exposure scenarios were 0, 1, 5, 10, 25, and 50 g Ag/g dry...... weight (dw) sediment. Our results showed that Ag was able to cause DNA damage in Nereis coelomocytes, and that this effect was both concentration- and Ag form-related. There was significantly greater genotoxicity (higher tail moment and tail DNA intensities) at 25 and 50 g/g dw in nano- and micron-Ag...

Nano silicon for lithium-ion batteries

International Nuclear Information System (INIS)

Holzapfel, Michael; Buqa, Hilmi; Hardwick, Laurence J.; Hahn, Matthias; Wuersig, Andreas; Scheifele, Werner; Novak, Petr; Koetz, Ruediger; Veit, Claudia; Petrat, Frank-Martin

2006-01-01

New results for two types of nano-size silicon, prepared via thermal vapour deposition either with or without a graphite substrate are presented. Their superior reversible charge capacity and cycle life as negative electrode material for lithium-ion batteries have already been shown in previous work. Here the lithiation reaction of the materials is investigated more closely via different electrochemical in situ techniques: Raman spectroscopy, dilatometry and differential electrochemical mass spectrometry (DEMS). The Si/graphite compound material shows relatively high kinetics upon discharge. The moderate relative volume change and low gas evolution of the nano silicon based electrode, both being important points for a possible future use in real batteries, are discussed with respect to a standard graphite electrode

Heat Conduction of Air in Nano Spacing

Directory of Open Access Journals (Sweden)

Zhang Yao-Zhong

2009-01-01

Full Text Available Abstract The scale effect of heat conduction of air in nano spacing (NS is very important for nanodevices to improve their life and efficiency. By constructing a special technique, the changes of heat conduction of air were studied by means of measuring the heat conduction with heat conduction instrument in NS between the hot plate and the cooling plate. Carbon nanotubes were used to produce the nano spacing. The results show that when the spacing is small down to nanometer scale, heat conduction plays a prominent role in NS. It was found that the thickness of air is a non-linear parameter for demarcating the heat conduction of air in NS and the rate of heat conduction in unit area could be regard as a typical parameter for the heat conduction characterization at nanometer scale.

DNA Tetrahedron Delivery Enhances Doxorubicin-Induced Apoptosis of HT-29 Colon Cancer Cells

Science.gov (United States)

Zhang, Guiyu; Zhang, Zhiyong; Yang, Junen

2017-08-01

As a nano-sized drug carrier with the advantage of modifiability and proper biocompatibility, DNA tetrahedron (DNA tetra) delivery is hopeful to enhance the inhibitory efficiency of nontargeted anticancer drugs. In this investigation, doxorubicin (Dox) was assembled to a folic acid-modified DNA tetra via click chemistry to prepare a targeted antitumor agent. Cellular uptake efficiency was measured via fluorescent imaging. Cytotoxicity, inhibition efficiency, and corresponding mechanism on colon cancer cell line HT-29 were evaluated by MTT assay, cell proliferation curve, western blot, and flow cytometry. No cytotoxicity was induced by DNA tetra, but the cellular uptake ratio increased obviously resulting from the DNA tetra-facilitated penetration through cellular membrane. Accordingly, folic acid-DNA tetra-Dox markedly increased the antitumor efficiency with increased apoptosis levels. In details, 100 μM was the effective concentration and a 6-h incubation period was needed for apoptosis induction. In conclusion, nano-sized DNA tetrahedron was a safe and effective delivery system for Dox and correspondingly enhanced the anticancer efficiency.

The Potential of Nano materials for Drug Delivery, Cell Tracking, and Regenerative Medicine 2014

International Nuclear Information System (INIS)

Vasilev, K.; Vasilev, K.; Chen, H.; Murray, P.; Mantovani, D.

2014-01-01

Nano materials have become the building blocks of revolutionary technologies that have opened unprecedented opportunities across the entire global economy. Nano materials are particulates of various shapes and forms and assemblies that typically have a size range between 1 and 100 nm. Nature has designed and used nano materials for billions of years. For instance, proteins and viruses are complex nano engineered structures that have been designed by Nature to perform highly specific and refined roles. It was only in the last two decades that we learned how to engineer and use materials at the nano scale in a relatively large scale. Despite revolutionizing many technologies, these materials are far from the perfection that Nature has created. Thus, scientists and engineers are presented with enormous challenges and opportunities to explore, interrogate, and utilize the unique properties of nano materials to improve standards of living and drive economic prosperity

Design for manufacturability and yield for nano-scale CMOS

CERN Document Server

Chiang, Charles C

2007-01-01

Talks about the various aspects of manufacturability and yield in a nano-CMOS process and how to address each aspect at the proper design step starting with the design and layout of standard cells. This book is suitable for practicing IC designer and for graduate students intent on having a career in IC design or in EDA tool development.

MEMS and Nano-Technology Clean Room

Data.gov (United States)

Federal Laboratory Consortium — The MEMS and Nano-Technology Clean Room is a state-of-the-art, 800 square foot, Class 1000-capable facility used for development of micro and sub-micro scale sensors...

DNA Photo Lithography with Cinnamate-based Photo-Bio-Nano-Glue

Science.gov (United States)

Feng, Lang; Li, Minfeng; Romulus, Joy; Sha, Ruojie; Royer, John; Wu, Kun-Ta; Xu, Qin; Seeman, Nadrian; Weck, Marcus; Chaikin, Paul

2013-03-01

We present a technique to make patterned functional surfaces, using a cinnamate photo cross-linker and photolithography. We have designed and modified a complementary set of single DNA strands to incorporate a pair of opposing cinnamate molecules. On exposure to 360nm UV, the cinnamate makes a highly specific covalent bond permanently linking only the complementary strands containing the cinnamates. We have studied this specific and efficient crosslinking with cinnamate-containing DNA in solution and on particles. UV addressability allows us to pattern surfaces functionally. The entire surface is coated with a DNA sequence A incorporating cinnamate. DNA strands A'B with one end containing a complementary cinnamated sequence A' attached to another sequence B, are then hybridized to the surface. UV photolithography is used to bind the A'B strand in a specific pattern. The system is heated and the unbound DNA is washed away. The pattern is then observed by thermo-reversibly hybridizing either fluorescently dyed B' strands complementary to B, or colloids coated with B' strands. Our techniques can be used to reversibly and/or permanently bind, via DNA linkers, an assortment of molecules, proteins and nanostructures. Potential applications range from advanced self-assembly, such as templated self-replication schemes recently reported, to designed physical and chemical patterns, to high-resolution multi-functional DNA surfaces for genetic detection or DNA computing.

Nano materials for the Local and Targeted Delivery of Osteoarthritis Drugs

International Nuclear Information System (INIS)

Periyasamy, P.C.; Leijten, J.C.H.; Dijkstra, P.J.; Karperien, M.; Post, J.N.

2012-01-01

Nano technology has found its potential in every possible field of science and engineering. It offers a plethora of options to design tools at the nanometer scale, which can be expected to function more effectively than micro- and macro systems for specific applications. Although the debate regarding the safety of synthetic nano materials for clinical applications endures, it is a promising technology due to its potential to augment current treatments. Various materials such as synthetic polymer, biopolymers, or naturally occurring materials such as proteins and peptides can serve as building blocks for adaptive nano scale formulations. The choice of materials depends highly on the application. We focus on the use of nanoparticles for the treatment of degenerative cartilage diseases, such as osteoarthritis (OA). Current therapies for OA focus on treating the symptoms rather than modifying the disease. The usefulness of OA disease modifying drugs is hampered by side effects and lack of suitable drug delivery systems that target, deliver, and retain drugs locally. This challenge can be overcome by using nano technological formulations. We describe the different nano drug delivery systems and their potential for cartilage repair. This paper provides the reader basal understanding of nano materials and aims at drawing new perspectives on the use of existing nano technological formulations for the treatment of osteoarthritis.

Extraction and characterization of cellulose nano whiskers from balsa wood

International Nuclear Information System (INIS)

Morelli, Carolina L.; Bretas, Rosario E.S.; Marconcini, Jose M.; Pereira, Fabiano V.; Branciforti, Marcia C.

2011-01-01

In this study cellulose nano whiskers were obtained from balsa wood. For this purpose, fibers of balsa wood were subjected to hydrolysis reactions for lignin and hemi cellulose digestion and acquisition of nano-scale cellulose. Cellulose nano crystals obtained had medium length and thickness of 176 nm and 7 nm respectively. Infrared spectroscopy and x-ray diffraction showed that the process used for extracting nano whiskers could digest nearly all the lignin and hemi cellulose from the balsa fiber and still preserve the aspect ratio and crystallinity, satisfactory enough for future application in polymer nano composites. Thermogravimetry showed that the onset temperature of thermal degradation of cellulose nano crystals (226 degree C) was higher than the temperature of the balsa fiber (215 degree C), allowing its use in molding processes with many polymers from the molten state.(author)

Fractal assembly of micrometre-scale DNA origami arrays with arbitrary patterns

Science.gov (United States)

Tikhomirov, Grigory; Petersen, Philip; Qian, Lulu

2017-12-01

Self-assembled DNA nanostructures enable nanometre-precise patterning that can be used to create programmable molecular machines and arrays of functional materials. DNA origami is particularly versatile in this context because each DNA strand in the origami nanostructure occupies a unique position and can serve as a uniquely addressable pixel. However, the scale of such structures has been limited to about 0.05 square micrometres, hindering applications that demand a larger layout and integration with more conventional patterning methods. Hierarchical multistage assembly of simple sets of tiles can in principle overcome this limitation, but so far has not been sufficiently robust to enable successful implementation of larger structures using DNA origami tiles. Here we show that by using simple local assembly rules that are modified and applied recursively throughout a hierarchical, multistage assembly process, a small and constant set of unique DNA strands can be used to create DNA origami arrays of increasing size and with arbitrary patterns. We illustrate this method, which we term ‘fractal assembly’, by producing DNA origami arrays with sizes of up to 0.5 square micrometres and with up to 8,704 pixels, allowing us to render images such as the Mona Lisa and a rooster. We find that self-assembly of the tiles into arrays is unaffected by changes in surface patterns on the tiles, and that the yield of the fractal assembly process corresponds to about 0.95m - 1 for arrays containing m tiles. When used in conjunction with a software tool that we developed that converts an arbitrary pattern into DNA sequences and experimental protocols, our assembly method is readily accessible and will facilitate the construction of sophisticated materials and devices with sizes similar to that of a bacterium using DNA nanostructures.

Economical hydrogen production by electrolysis using nano pulsed DC

Energy Technology Data Exchange (ETDEWEB)

Dharmaraj, C.H. [Tangedco, Tirunelveli, ME Environmental Engineering (India); Adshkumar, S. [Department of Civil Engineering, Anna University of Technology Tirunelveli, Tirunelveli - 627007 (India)

2012-07-01

Hydrogen is an alternate renewable eco fuel. The environmental friendly hydrogen production method is electrolysis. The cost of electrical energy input is major role while fixing hydrogen cost in the conventional direct current Electrolysis. Using nano pulse DC input makes the input power less and economical hydrogen production can be established. In this investigation, a lab scale electrolytic cell developed and 0.58 mL/sec hydrogen/oxygen output is obtained using conventional and nano pulsed DC. The result shows that the nano pulsed DC gives 96.8 % energy saving.

Measurement capability overview in PolyNano

DEFF Research Database (Denmark)

Calaon, Matteo; Tosello, Guido; Hansen, Hans Nørgaard

2012-01-01

A measurement capability overview has been conducted to evaluate, among the most used instruments in the field of nanometrology, where the PolyNano project should focus its research. The deliverable presents the most relevant instruments to achieve the best possible measurements accuracy matching...... requirements such as low uncertainty, high repeatability and resolution, adequate measuring range and availability among the different project partners. Based on the present measurement capability overview and in relation to the objective of PolyNano to “remove the technology barrier between lab‐scale proof...

An angled nano-tunnel fabricated on poly(methyl methacrylate) by a focused ion beam

International Nuclear Information System (INIS)

Her, Eun Kyu; Chung, Hee-Suk; Oh, Kyu Hwan; Moon, Myoung-Woon

2009-01-01

Angled nano-scale tunnels with high aspect ratio were fabricated on poly(methyl methacrylate) (PMMA) using a focused ion beam (FIB). The fabrication parameters such as ion fluence, incidence angle, and acceleration voltage of the Ga + ion beam were first studied on the PMMA surface to explore the formation of the nano-scale configurations such as nano-holes and cones with diameter in the range of 50-150 nm at an ion beam acceleration voltage of 5-20 kV. It was also found that the PMMA surface exposed to FIB was changed into an amorphous graphitic structure. Angled nano-scale tunnels were fabricated with high aspect ratio of 700-1500 nm in depth and 60 nm in mean diameter at an ion beam acceleration voltage of 5 kV and under a specific ion beam current. The angle of the nano-tunnels was found to follow the incident angle of the ion beam tilted from 0 0 to 85 0 , which has the potential for creating a mold for anisotropic adhesives by mimicking the hairs on a gecko's feet.

Fabrication and thermal oxidation of ZnO nano fibers prepared via electro spinning technique

International Nuclear Information System (INIS)

Baek, Jeongha; Park, Juyun; Kim, Don; Kang, Yongcheol; Koh, Sungwi; Kang, Jisoo

2012-01-01

Materials on the scale of nano scale have widely been used as research topics because of their interesting characteristics and aspects they bring into the field. Out of the many metal oxides, zinc oxide (ZnO) was chosen to be fabricated as nano fibers using the electro spinning method for potential uses of solar cells and sensors. After ZnO nano fibers were obtained, calcination temperature effects on the ZnO nano fibers were studied and reported here. The results of scanning electron microscopy (SEM) revealed that the aggregation of the ZnO nano fibers progressed by calcination. X-ray diffraction (XRD) study showed the hcp ZnO structure was enhanced by calcination at 873 and 1173 K. Transmission electron microscopy (TEM) confirmed the crystallinity of the calcined ZnO nano fibers. X-ray photoelectron spectroscopy (XPS) verified the thermal oxidation of Zn species by calcination in the nano fibers. These techniques have helped US deduce the facts that the diameter of ZnO increases as the calcination temperature was raised; the process of calcination affects the crystallinity of ZnO nano fibers, and the thermal oxidation of Zn species was observed as the calcination temperature was raised

The many faces of nano in newspaper reporting

International Nuclear Information System (INIS)

Boholm, Max; Boholm, Åsa

2012-01-01

The morpheme nano in languages such as Swedish and English is a constituent of many words. This article linguistically analyses the meaning potential of nano by focusing on word use in a Swedish newspaper corpus comprising 2,564 articles (1.6 million words) covering a 22-year period (1988–2010). Close to 400 word forms having nano as a constituent have been identified and analyzed. The results suggest that nano covers a broad and heterogeneous conceptual field: (i) as a prefix of the SI system; (ii) in relation to the scientific activities of nanoscience and nanotechnology, including their sub-processes and actors; and (iii) in relation to objects. The identified meanings of nano, besides the standard definition (i.e. ‘billionth part’ in relation to SI units), are ‘operating at the nanometre level’ in relation to activities and their actors and ‘nanometre sized’ and ‘nanotechnological’ in relation to objects; in addition, the less precise and non-technical meaning ‘very small’ is identified. We discuss the implications of the findings for a hypothesis about media influence on public understanding of technology, suggesting that repeated findings in Europe and the USA of little self-reported understanding and knowledge of nanotechnology or nanoscience among the public make sense in light of the polysemy of nano reflected in its broad variety of verbal forms and usages.

The many faces of nano in newspaper reporting

Science.gov (United States)

Boholm, Max; Boholm, Åsa

2012-02-01

The morpheme nano in languages such as Swedish and English is a constituent of many words. This article linguistically analyses the meaning potential of nano by focusing on word use in a Swedish newspaper corpus comprising 2,564 articles (1.6 million words) covering a 22-year period (1988-2010). Close to 400 word forms having nano as a constituent have been identified and analyzed. The results suggest that nano covers a broad and heterogeneous conceptual field: (i) as a prefix of the SI system; (ii) in relation to the scientific activities of nanoscience and nanotechnology, including their sub-processes and actors; and (iii) in relation to objects. The identified meanings of nano, besides the standard definition (i.e. `billionth part' in relation to SI units), are `operating at the nanometre level' in relation to activities and their actors and `nanometre sized' and `nanotechnological' in relation to objects; in addition, the less precise and non-technical meaning `very small' is identified. We discuss the implications of the findings for a hypothesis about media influence on public understanding of technology, suggesting that repeated findings in Europe and the USA of little self-reported understanding and knowledge of nanotechnology or nanoscience among the public make sense in light of the polysemy of nano reflected in its broad variety of verbal forms and usages.

Nano- and Macro-wear of Bio-carbo-nitrided AISI 8620 Steel Surfaces

Science.gov (United States)

Arthur, Emmanuel Kwesi; Ampaw, Edward; Zebaze Kana, M. G.; Adetunji, A. R.; Olusunle, S. O. O.; Adewoye, O. O.; Soboyejo, W. O.

2015-12-01

This paper presents the results of an experimental study of nano- and macro-scale wear in a carbo-nitrided AISI 8620 steel. Carbo-nitriding is carried out using a novel method that involves the use of dried, cyanide-containing cassava leaves, as sources of carbon and nitrogen. These are used in a pack cementation that is used to diffuse carbon and nitrogen into case layers at intermediate temperatures [673.15 K, 723.15 K, 773.15 K, and 823.15 K (400 °C, 450 °C, 500 °C, and 550 °C)]. Nano- and macro-scale wear properties are studied in the case-hardened surfaces, using a combination of nano-scratch and pin-on-disk experiments. The measured wear volumes (at both nano- and macro-length scales) are shown to increase with decreasing pack cyaniding temperature. The nano- and macro-wear resistances are also shown to be enhanced by the in situ diffusion of carbon and nitrogen from cyanide-containing bio-processed waste. The underlying wear mechanisms are also elucidated via atomic force microscopy and scanning electron microscopy observations of the wear tracks. The implications of the results are discussed for the design of hardened carbo-nitrided steel surfaces with improved wear resistance.

Distinct energetics and closing pathways for DNA polymerase β with 8-oxoG template and different incoming nucleotides

Directory of Open Access Journals (Sweden)

Wang Yanli

2007-02-01

Full Text Available Abstract Background 8-Oxoguanine (8-oxoG is a common oxidative lesion frequently encountered by DNA polymerases such as the repair enzyme DNA polymerase β (pol β. To interpret in atomic and energetic detail how pol β processes 8-oxoG, we apply transition path sampling to delineate closing pathways of pol β 8-oxoG complexes with dCTP and dATP incoming nucleotides and compare the results to those of the nonlesioned G:dCTP and G:dATPanalogues. Results Our analyses show that the closing pathways of the 8-oxoG complexes are different from one another and from the nonlesioned analogues in terms of the individual transition states along each pathway, associated energies, and the stability of each pathway's closed state relative to the corresponding open state. In particular, the closed-to-open state stability difference in each system establishes a hierarchy of stability (from high to low as G:C > 8-oxoG:C > 8-oxoG:A > G:A, corresponding to -3, -2, 2, 9 kBT, respectively. This hierarchy of closed state stability parallels the experimentally observed processing efficiencies for the four pairs. Network models based on the calculated rate constants in each pathway indicate that the closed species are more populated than the open species for 8-oxoG:dCTP, whereas the opposite is true for 8-oxoG:dATP. Conclusion These results suggest that the lower insertion efficiency (larger Km for dATP compared to dCTP opposite 8-oxoG is caused by a less stable closed-form of pol β, destabilized by unfavorable interactions between Tyr271 and the mispair. This stability of the closed vs. open form can also explain the higher insertion efficiency for 8-oxoG:dATP compared to the nonlesioned G:dATP pair, which also has a higher overall conformational barrier. Our study offers atomic details of the complexes at different states, in addition to helping interpret the different insertion efficiencies of dATP and dCTP opposite 8-oxoG and G.

Light-driven nano-robotics for sub-diffraction probing and sensing

DEFF Research Database (Denmark)

Glückstad, Jesper; Bañas, Andrew Rafael; Palima, Darwin

On the macro-scale robotics typically uses light for carrying information for machine vision for and feedback in artificially intelligent guidance systems and monitoring. Using the miniscule momentum of light shrinking robots down to the micro- and even nano-scale regime creates opportunities......]. Therefore, a generic approach for optimizing lightmatter interaction involves the combination of optimal light-shaping techniques with the use of optimized nano-featured shapes in light-driven micro-robotics structures. In this work, we designed different three-dimensional micro-structures and fabricated...

Environmentally benign graphite intercalation compound composition for exfoliated graphite, flexible graphite, and nano-scaled graphene platelets

Science.gov (United States)

Zhamu, Aruna; Jang, Bor Z.

2014-06-17

A carboxylic-intercalated graphite compound composition for the production of exfoliated graphite, flexible graphite, or nano-scaled graphene platelets. The composition comprises a layered graphite with interlayer spaces or interstices and a carboxylic acid residing in at least one of the interstices, wherein the composition is prepared by a chemical oxidation reaction which uses a combination of a carboxylic acid and hydrogen peroxide as an intercalate source. Alternatively, the composition may be prepared by an electrochemical reaction, which uses a carboxylic acid as both an electrolyte and an intercalate source. Exfoliation of the invented composition does not release undesirable chemical contaminants into air or drainage.

A multi-level capacitor-less memory cell fabricated on a nano-scale strained silicon-on-insulator

International Nuclear Information System (INIS)

Park, Jea-Gun; Kim, Seong-Je; Shin, Mi-Hee; Song, Seung-Hyun; Shim, Tae-Hun; Chung, Sung-Woong; Enomoto, Hirofumi

2011-01-01

A multi-level capacitor-less memory cell was fabricated with a fully depleted n-metal-oxide-semiconductor field-effect transistor on a nano-scale strained silicon channel on insulator (FD sSOI n-MOSFET). The 0.73% biaxial tensile strain in the silicon channel of the FD sSOI n-MOSFET enhanced the effective electron mobility to ∼ 1.7 times that with an unstrained silicon channel. This thereby enables both front- and back-gate cell operations, demonstrating eight-level volatile memory-cell operation with a 1 ms retention time and 12 μA memory margin. This is a step toward achieving a terabit volatile memory cell.

Transparent and conductive electrodes by large-scale nano-structuring of noble metal thin-films

DEFF Research Database (Denmark)

Linnet, Jes; Runge Walther, Anders; Wolff, Christian

2018-01-01

grid, and nano-wire thin-films. The indium and carbon films do not match the chemical stability nor the electrical performance of the noble metals, and many metal films are not uniform in material distribution leading to significant surface roughness and randomized transmission haze. We demonstrate...... solution-processed masks for physical vapor-deposited metal electrodes consisting of hexagonally ordered aperture arrays with scalable aperture-size and spacing in an otherwise homogeneous noble metal thin-film that may exhibit better electrical performance than carbon nanotube-based thin-films...... for equivalent optical transparency. The fabricated electrodes are characterized optically and electrically by measuring transmittance and sheet resistance. The presented methods yield large-scale reproducible results. Experimentally realized thin-films with very low sheet resistance, Rsh = 2.01 ± 0.14 Ω...

Controlling nitrogen migration through micro-nano networks.

Science.gov (United States)

Cai, Dongqing; Wu, Zhengyan; Jiang, Jiang; Wu, Yuejin; Feng, Huiyun; Brown, Ian G; Chu, Paul K; Yu, Zengliang

2014-01-14

Nitrogen fertilizer unabsorbed by crops eventually discharges into the environment through runoff, leaching and volatilization, resulting in three-dimensional (3D) pollution spanning from underground into space. Here we describe an approach for controlling nitrogen loss, developed using loss control fertilizer (LCF) prepared by adding modified natural nanoclay (attapulgite) to traditional fertilizer. In the aqueous phase, LCF self-assembles to form 3D micro/nano networks via hydrogen bonds and other weak interactions, obtaining a higher nitrogen spatial scale so that it is retained by a soil filtering layer. Thus nitrogen loss is reduced and sufficient nutrition for crops is supplied, while the pollution risk of the fertilizer is substantially lowered. As such, self-fabrication of nano-material was used to manipulate the nitrogen spatial scale, which provides a novel and promising approach for the research and control of the migration of other micro-scaled pollutants in environmental medium.

Toxic effects and bioaccumulation of nano-, micron- and ionic-Ag in the polychaete, Nereis diversicolor

DEFF Research Database (Denmark)

cong, Yi; Banta, Gary Thomas; Selck, Henriette

There is increasing concern about the toxicities and potential risks, both still poorly understood, of silver nanoparticles for the aquatic environment after their eventual release. In this study, the toxicities of nano (AgNO3)-Ag on the sediment......-dwelling polychaete, Nereis diversicolor, were compared after 10 d of sediment exposure, using growth, DNA damage (comet assay) and bioaccumulation as endpoints. The nominal concentrations used in all exposure scenarios were 0, 1, 5, 10, 25, 50 µg Ag/g dry weight (dw) sediment. Our results show that Ag is able...... to cause DNA damage in Nereis coelomocytes and that this effect is both concentration- and Ag form-related. There were significantly greater genotoxity (higher tail moment and tail DNA intensities) at 25 and 50 µg/g dw in nano- and micron-Ag treated groups and at 50 µg/g dw in ionic-Ag treated group...

Testing DNA barcodes in closely related species of Curcuma (Zingiberaceae) from Myanmar and China.

Science.gov (United States)

Chen, Juan; Zhao, Jietang; Erickson, David L; Xia, Nianhe; Kress, W John

2015-03-01

The genus Curcuma L. is commonly used as spices, medicines, dyes and ornamentals. Owing to its economic significance and lack of clear-cut morphological differences between species, this genus is an ideal case for developing DNA barcodes. In this study, four chloroplast DNA regions (matK, rbcL, trnH-psbA and trnL-F) and one nuclear region (ITS2) were generated for 44 Curcuma species and five species from closely related genera, represented by 96 samples. PCR amplification success rate, intra- and inter-specific genetic distance variation and the correct identification percentage were taken into account to assess candidate barcode regions. PCR and sequence success rate were high in matK (89.7%), rbcL (100%), trnH-psbA (100%), trnL-F (95.7%) and ITS2 (82.6%) regions. The results further showed that four candidate chloroplast barcoding regions (matK, rbcL, trnH-psbA and trnL-F) yield no barcode gaps, indicating that the genus Curcuma represents a challenging group for DNA barcoding. The ITS2 region presented large interspecific variation and provided the highest correct identification rates (46.7%) based on BLASTClust method among the five regions. However, the ITS2 only provided 7.9% based on NJ tree method. An increase in discriminatory power needs the development of more variable markers. © 2014 John Wiley & Sons Ltd.

DNA nanotechnology: a future perspective

Science.gov (United States)

2013-01-01

In addition to its genetic function, DNA is one of the most distinct and smart self-assembling nanomaterials. DNA nanotechnology exploits the predictable self-assembly of DNA oligonucleotides to design and assemble innovative and highly discrete nanostructures. Highly ordered DNA motifs are capable of providing an ultra-fine framework for the next generation of nanofabrications. The majority of these applications are based upon the complementarity of DNA base pairing: adenine with thymine, and guanine with cytosine. DNA provides an intelligent route for the creation of nanoarchitectures with programmable and predictable patterns. DNA strands twist along one helix for a number of bases before switching to the other helix by passing through a crossover junction. The association of two crossovers keeps the helices parallel and holds them tightly together, allowing the assembly of bigger structures. Because of the DNA molecule's unique and novel characteristics, it can easily be applied in a vast variety of multidisciplinary research areas like biomedicine, computer science, nano/optoelectronics, and bionanotechnology. PMID:23497147

3rd International Conference on Micro and Nano Flows (MNF2011)

CERN Document Server

Koenig, Carola; Micro and Nano Flow Systems for Bioanalysis

2013-01-01

Micro and Nano Flow Systems for Bioanalysis addresses the latest developments in biomedical engineering at very small scales. It shows how organic systems require multi-scale understanding in the broadest sense whether the approach  is experimental or mathematical, and whether the physiological state is healthy or diseased. Micro-and nano-fluidics represent  key areas of translational research in which state-of-the-art engineering processes and devices are applied to bedside monitoring and treatment. By applying conventional micro- and nano-engineering to complex organic solids, fluids, and their interactions, leading researchers from throughout the world describe methods and techniques with great potential for use in medicine and clinical practice. Coverage includes the seeming plethora of new, fine-scale optical methods for measuring blood flow as well as endothelial activation and interaction with tissue. Generic areas of modeling and bioelectronics are also considered. In keeping with the recurring them...

Small scale optics

CERN Document Server

Yupapin, Preecha

2013-01-01

The behavior of light in small scale optics or nano/micro optical devices has shown promising results, which can be used for basic and applied research, especially in nanoelectronics. Small Scale Optics presents the use of optical nonlinear behaviors for spins, antennae, and whispering gallery modes within micro/nano devices and circuits, which can be used in many applications. This book proposes a new design for a small scale optical device-a microring resonator device. Most chapters are based on the proposed device, which uses a configuration know as a PANDA ring resonator. Analytical and nu

Functional Smart Dispersed Liquid Crystals for Nano- and Biophotonic Applications: Nanoparticles-Assisted Optical Bioimaging

Directory of Open Access Journals (Sweden)

N. V. Kamanina

2016-01-01

Full Text Available Functional nematic liquid crystal structures doped with nano- and bioobjects have been investigated. The self-assembling features and the photorefractive parameters of the structured liquid crystals have been comparatively studied via microscopy and laser techniques. Fullerene, quantum dots, carbon nanotubes, DNA, and erythrocytes have been considered as the effective nano- and biosensitizers of the LC mesophase. The holographic recording technique based on four-wave mixing of the laser beams has been used to investigate the laser-induced change of the refractive index in the nano- and bioobjects-doped liquid crystal cells. The special accent has been given to novel nanostructured relief with vertically aligned carbon nanotubes at the interface: solid substrate-liquid crystal mesophase. It has been shown that this nanostructured relief influences the orienting ability of the liquid crystal molecules with good advantage. As a result, it provokes the orientation of the DNA. The modified functional liquid crystal materials have been proposed as the perspective systems for both the photonics and biology as well as the medical applications.

Electrical characterization of Ge–Sb–Te phase change nano-pillars using conductive atomic force microscopy

International Nuclear Information System (INIS)

Bae, Byeong-Ju; Hong, Sung-Hoon; Hwang, Seon-Yong; Hwang, Jae-Yeon; Yang, Ki-Yeon; Lee, Heon

2009-01-01

The electrical characteristic of phase change material was studied in nano-scale using nanoimprint lithography and a conducting atomic force microscopy measurement system. Nanoimprint lithography was used to fabricate the nano-scale phase change material pattern. A Pt-coated AFM tip was used as a top electrode to measure the electrical characteristics of the GST nano-pillar. The GST nano-pillar, which is 200 nm in diameter, was amorphized by 2 V and 5 ns reset pulse and was then brought back to the crystalline phase by applying 1.3 V and 150 ns set pulse. Using this measurement system, the GST nano-pillar was switched between the amorphous and crystalline phases more than five times. The results of the reset and the set current measurement with the GST nano-pillar sizes show that the reset and the set currents also decreased with the decrease of the GST pillar size

Close encounters for the first time: Helicase interactions with DNA damage.

Science.gov (United States)

Khan, Irfan; Sommers, Joshua A; Brosh, Robert M

2015-09-01

DNA helicases are molecular motors that harness the energy of nucleoside triphosphate hydrolysis to unwinding structured DNA molecules that must be resolved during cellular replication, DNA repair, recombination, and transcription. In vivo, DNA helicases are expected to encounter a wide spectrum of covalent DNA modifications to the sugar phosphate backbone or the nitrogenous bases; these modifications can be induced by endogenous biochemical processes or exposure to environmental agents. The frequency of lesion abundance can vary depending on the lesion type. Certain adducts such as oxidative base modifications can be quite numerous, and their effects can be helix-distorting or subtle perturbations to DNA structure. Helicase encounters with specific DNA lesions and more novel forms of DNA damage will be discussed. We will also review the battery of assays that have been used to characterize helicase-catalyzed unwinding of damaged DNA substrates. Characterization of the effects of specific DNA adducts on unwinding by various DNA repair and replication helicases has proven to be insightful for understanding mechanistic and biological aspects of helicase function in cellular DNA metabolism. Published by Elsevier B.V.

Thorium/uranium mixed oxide nano-crystals: Synthesis, structural characterization and magnetic properties

International Nuclear Information System (INIS)

Hudry, Damien; Griveau, Jean-Christophe; Apostolidis, Christos; Colineau, Eric; Rasmussen, Gert; Walter, Olaf; Wang, Di; Venkata Sai Kiran Chakravadhaluna; Courtois, Eglantine; Kubel, Christian

2014-01-01

One of the primary aims of the actinide community within nano-science is to develop a good understanding similar to what is currently the case for stable elements. As a consequence, efficient, reliable and versatile synthesis techniques dedicated to the formation of new actinide-based nano-objects (e.g., nano-crystals) are necessary. Hence, a 'library' dedicated to the preparation of various actinide based nano-scale building blocks is currently being developed. Nano-scale building blocks with tunable sizes, shapes and compositions are of prime importance. So far, the non-aqueous synthesis method in highly coordinating organic media is the only approach which has demonstrated the capability to provide size and shape control of actinide-based nano-crystals (both for thorium and uranium, and recently extended to neptunium and plutonium). In this paper, we demonstrate that the non-aqueous approach is also well adapted to control the chemical composition of the nano-crystals obtained when mixing two different actinides. Indeed, the controlled hot co-injection of thorium acetylacetonate and uranyl acetate (together with additional capping agents) into benzyl ether can be used to synthesize thorium/uranium mixed oxide nano-crystals covering the full compositional spectrum. Additionally, we found that both size and shape are modified as a function of the thorium/uranium ratio. Finally, the magnetic properties of the different thorium/uranium mixed oxide nano-crystals were investigated. Contrary to several reports, we did not observe any ferromagnetic behavior. As a consequence, ferromagnetism cannot be described as a universal feature of nano-crystals of non-magnetic oxides as recently claimed in the literature. (authors)

Structure and photoluminescence properties of Ag-coated ZnO nano-needles

Energy Technology Data Exchange (ETDEWEB)

Li Xiaozhu, E-mail: Lixiaozhu1019@21cn.com [Department of Physics, Shaoguan University, Shaoguan, Guangdong 512005 (China) and Department of Physics and Key Laboratory of Acoustic and Photonic Materials and Devices of Ministry of Education, Wuhan University, Wuhan, Hubei 430072 (China); Wang Yongqian [Engineering Research Center of Nano-Geomaterials of Ministry of Education (China University of Geosciences), Wuhan, Hubei 430074 (China)

2011-05-12

Highlights: > ZnO nano-needles were synthesized by thermal oxidation. > Their surfaces were coated with Ag by pulse electro-deposition technique. > The uncoated and coated ZnO nano-needles were characterized. > The results showed that the prepared ZnO nano-needles have been coated with Ag successfully. > The photoluminescence spectrums of ZnO nano-needles with Ag-coated and uncoated were analyzed, finding that the Ag-coated ZnO nano-needles can increase the absorption of UV light. - Abstract: A large number of zinc oxide (ZnO) nano-needles were synthesized by thermal oxidation of pure zinc. The surfaces of ZnO nano-needles were coated with a layer of Ag by pulse electro-deposition technique. The uncoated and coated ZnO nano-needles were characterized by using the X-ray diffraction and the scanning electron microscope (SEM). The results showed that the uncoated samples were close-packed hexagonal structure, which showed needle-like morphology. Their average diameter is about 40 nm, lengths up to 5 {mu}m. At the same time we observed that the prepared ZnO nano-needles have been coated with Ag successfully. The photoluminescence spectrums of ZnO nano-needles with Ag-coated and uncoated were analyzed, finding that the uncoated ZnO nano-needles have two fluorescence peaks at 388 nm and 470.8 nm, respectively, the relative intensity of 143.4 and 93.61; and the Ag-coated ZnO nano-needles showed a pair of strong peaks at 387.4 nm and 405.2 nm, the relative intensity of 1366 and 1305, respectively, indicating that the Ag-coated ZnO nano-needles can increase the absorption of UV light.

Replication of micro and nano surface geometries

DEFF Research Database (Denmark)

Hansen, Hans Nørgaard; Hocken, R.J.; Tosello, Guido

2011-01-01

The paper describes the state-of-the-art in replication of surface texture and topography at micro and nano scale. The description includes replication of surfaces in polymers, metals and glass. Three different main technological areas enabled by surface replication processes are presented......: manufacture of net-shape micro/nano surfaces, tooling (i.e. master making), and surface quality control (metrology, inspection). Replication processes and methods as well as the metrology of surfaces to determine the degree of replication are presented and classified. Examples from various application areas...... are given including replication for surface texture measurements, surface roughness standards, manufacture of micro and nano structured functional surfaces, replicated surfaces for optical applications (e.g. optical gratings), and process chains based on combinations of repeated surface replication steps....

SiO2@FeSO4 nano composite: A recoverable nano-catalyst for eco-friendly synthesis oximes of carbonyl compounds

Directory of Open Access Journals (Sweden)

Mostafa Karimkoshteh

2016-01-01

Full Text Available Various aldoximes and ketoximes synthesis of corresponding aldehydes and ketones in the presence of SiO2@FeSO4 nano composite as recoverable nano catalyst and NH2OH·HCl. The SiO2@FeSO4 nano composite system was carried out between 10 to 15 min in oil bath (70-80 °C under solvent-free condition in excellent yields in addition this protocol can be used for industrial scales. This method offers some advantages in term of clean reaction conditions, easy work-up procedure, short reaction time, applied to convert α-diketones to α-diketoximes (as longer than other carbonyl compounds, α,β-unsaturated aldehydes and ketones to corresponding oximes and suppression of any side product. So we think that NH2OH•HCl/SiO2@FeSO4 nano composite system could be considered a new and useful addition to the present methodologies in this area. Structure of products and nano composite elucidation was carried out by 1H NMR, 13C NMR, FT-IR, scanning electron microscopy (SEM.

Ab initio Calculations of Electronic Fingerprints of DNA bases on Graphene

Science.gov (United States)

Ahmed, Towfiq; Rehr, John J.; Kilina, Svetlana; Das, Tanmoy; Haraldsen, Jason T.; Balatsky, Alexander V.

2012-02-01

We have carried out first principles DFT calculations of the electronic local density of states (LDOS) of DNA nucleotide bases (A,C,G,T) adsorbed on graphene using LDA with ultra-soft pseudo-potentials. We have also calculated the longitudinal transmission currents T(E) through graphene nano-pores as an individual DNA base passes through it, using a non-equilibrium Green's function (NEGF) formalism. We observe several dominant base-dependent features in the LDOS and T(E) in an energy range within a few eV of the Fermi level. These features can serve as electronic fingerprints for the identification of individual bases from dI/dV measurements in scanning tunneling spectroscopy (STS) and nano-pore experiments. Thus these electronic signatures can provide an alternative approach to DNA sequencing.

Nano-Continuum Modeling of a Nuclear Glass Specimen Altered for 25 Years

Energy Technology Data Exchange (ETDEWEB)

Steefel, Carl

2014-01-06

The purpose of this contribution is to report on preliminary nano-continuum scale modeling of nuclear waste glass corrosion. The focus of the modeling is an experiment involving a French glass SON68 specimen leached for 25 years in a granitic environment. In this report, we focus on capturing the nano-scale concentration profiles. We use a high resolution continuum model with a constant grid spacing of 1 nanometer to investigate the glass corrosion mechanisms.

Superhydrophobic multi-scale ZnO nanostructures fabricated by chemical vapor deposition method.

Science.gov (United States)

Zhou, Ming; Feng, Chengheng; Wu, Chunxia; Ma, Weiwei; Cai, Lan

2009-07-01

The ZnO nanostructures were synthesized on Si(100) substrates by chemical vapor deposition (CVD) method. Different Morphologies of ZnO nanostructures, such as nanoparticle film, micro-pillar and micro-nano multi-structure, were obtained with different conditions. The results of XRD and TEM showed the good quality of ZnO crystal growth. Selected area electron diffraction analysis indicates the individual nano-wire is single crystal. The wettability of ZnO was studied by contact angle admeasuring apparatus. We found that the wettability can be changed from hydrophobic to super-hydrophobic when the structure changed from smooth particle film to single micro-pillar, nano-wire and micro-nano multi-scale structure. Compared with the particle film with contact angle (CA) of 90.7 degrees, the CA of single scale microstructure and sparse micro-nano multi-scale structure is 130-140 degrees, 140-150 degrees respectively. But when the surface is dense micro-nano multi-scale structure such as nano-lawn, the CA can reach to 168.2 degrees . The results indicate that microstructure of surface is very important to the surface wettability. The wettability on the micro-nano multi-structure is better than single-scale structure, and that of dense micro-nano multi-structure is better than sparse multi-structure.

A liposomal steroid nano-drug for treating systemic lupus erythematosus.

Science.gov (United States)

Moallem, E; Koren, E; Ulmansky, R; Pizov, G; Barlev, M; Barenholz, Y; Naparstek, Y

2016-10-01

Glucocorticoids have been known for years to be the most effective therapy in systemic lupus erythematosus. Their use, however, is limited by the need for high doses due to their unfavorable pharmacokinetics and biodistribution. We have previously developed a novel liposome-based steroidal (methylprednisolone hemisuccinate (MPS)) nano-drug and demonstrated its specific accumulation in inflamed tissues, as well as its superior therapeutic efficacy over that of free glucocorticoids (non-liposomal) in the autoimmune diseases, including the adjuvant arthritis rat model and the experimental autoimmune encephalomyelitis mouse model. In the present work we have evaluated the therapeutic effect of the above liposome-based steroidal (MPS) nano-drug in the MRL-lpr/lpr murine model of SLE and compared it with similar doses of the free MPS. MRL-lpr/lpr mice were treated with daily injections of free MPS or weekly injections of 10% dextrose, empty nano-liposomes or the steroidal nano-drug and the course of their disease was followed up to the age of 24 weeks. Treatment with the steroidal nano-drug was found to be significantly superior to the free MPS in suppressing anti-dsDNA antibody levels, proliferation of lymphoid tissue and renal damage, and in prolonging survival of animals. This significant superiority of our liposome based steroidal nano-drug administered weekly compared with daily injections of free methylprednisolone hemisuccinate in suppressing murine lupus indicates this glucocorticoid nano-drug formulation may be a good candidate for the treatment of human SLE. © The Author(s) 2016.

Magnetic bead detection using nano-transformers

Energy Technology Data Exchange (ETDEWEB)

Kim, Hyung Kwon; Ahn, Doyeol [Institute of Quantum Information Processing and Systems, University of Seoul, 90 Jeonnong, Dongdaemun, Seoul 130-743 (Korea, Republic of); Hwang, Jong Seung; Hwang, Sung Woo, E-mail: dahn@uos.ac.kr [Research Center for Time-domain Nano-functional Devices and School of Electrical Engineering, Korea University, 5-1 Anam, Sungbuk, Seoul 136-701 (Korea, Republic of)

2010-11-19

A novel scheme to detect magnetic beads using a nano-scale transformer with a femtoweber resolution is reported. We have performed a Faraday's induction experiment with the nano-transformer at room temperature. The transformer shows the linear output voltage responses to the sinusoidal input current. When magnetic beads are placed on the transformer, the output responses are increased by an amount corresponding to the added magnetic flux from the beads when compared with the case of no beads on the transformer. In this way, we could determine whether magnetic beads are on top of the transformer in a single particle level.

Magnetic bead detection using nano-transformers.

Science.gov (United States)

Kim, Hyung Kwon; Hwang, Jong Seung; Hwang, Sung Woo; Ahn, Doyeol

2010-11-19

A novel scheme to detect magnetic beads using a nano-scale transformer with a femtoweber resolution is reported. We have performed a Faraday's induction experiment with the nano-transformer at room temperature. The transformer shows the linear output voltage responses to the sinusoidal input current. When magnetic beads are placed on the transformer, the output responses are increased by an amount corresponding to the added magnetic flux from the beads when compared with the case of no beads on the transformer. In this way, we could determine whether magnetic beads are on top of the transformer in a single particle level.

Generation of covalently closed circular DNA of hepatitis B viruses via intracellular recycling is regulated in a virus specific manner.

Directory of Open Access Journals (Sweden)

Josef Köck

Full Text Available Persistence of hepatitis B virus (HBV infection requires covalently closed circular (cccDNA formation and amplification, which can occur via intracellular recycling of the viral polymerase-linked relaxed circular (rc DNA genomes present in virions. Here we reveal a fundamental difference between HBV and the related duck hepatitis B virus (DHBV in the recycling mechanism. Direct comparison of HBV and DHBV cccDNA amplification in cross-species transfection experiments showed that, in the same human cell background, DHBV but not HBV rcDNA converts efficiently into cccDNA. By characterizing the distinct forms of HBV and DHBV rcDNA accumulating in the cells we find that nuclear import, complete versus partial release from the capsid and complete versus partial removal of the covalently bound polymerase contribute to limiting HBV cccDNA formation; particularly, we identify genome region-selectively opened nuclear capsids as a putative novel HBV uncoating intermediate. However, the presence in the nucleus of around 40% of completely uncoated rcDNA that lacks most if not all of the covalently bound protein strongly suggests a major block further downstream that operates in the HBV but not DHBV recycling pathway. In summary, our results uncover an unexpected contribution of the virus to cccDNA formation that might help to better understand the persistence of HBV infection. Moreover, efficient DHBV cccDNA formation in human hepatoma cells should greatly facilitate experimental identification, and possibly inhibition, of the human cell factors involved in the process.

Nano-islands Based Charge Trapping Memory: A Scalability Study

KAUST Repository

Elatab, Nazek; Saadat, Irfan; Saraswat, Krishna; Nayfeh, Ammar

2017-01-01

Zinc-oxide (ZnO) and zirconia (ZrO2) metal oxides have been studied extensively in the past few decades with several potential applications including memory devices. In this work, a scalability study, based on the ITRS roadmap, is conducted on memory devices with ZnO and ZrO2 nano-islands charge trapping layer. Both nano-islands are deposited using atomic layer deposition (ALD), however, the different sizes, distribution and properties of the materials result in different memory performance. The results show that at the 32-nm node charge trapping memory with 127 ZrO2 nano-islands can provide a 9.4 V memory window. However, with ZnO only 31 nano-islands can provide a window of 2.5 V. The results indicate that ZrO2 nano-islands are more promising than ZnO in scaled down devices due to their higher density, higher-k, and absence of quantum confinement effects.

Nano-islands Based Charge Trapping Memory: A Scalability Study

KAUST Repository

Elatab, Nazek

2017-10-19

Zinc-oxide (ZnO) and zirconia (ZrO2) metal oxides have been studied extensively in the past few decades with several potential applications including memory devices. In this work, a scalability study, based on the ITRS roadmap, is conducted on memory devices with ZnO and ZrO2 nano-islands charge trapping layer. Both nano-islands are deposited using atomic layer deposition (ALD), however, the different sizes, distribution and properties of the materials result in different memory performance. The results show that at the 32-nm node charge trapping memory with 127 ZrO2 nano-islands can provide a 9.4 V memory window. However, with ZnO only 31 nano-islands can provide a window of 2.5 V. The results indicate that ZrO2 nano-islands are more promising than ZnO in scaled down devices due to their higher density, higher-k, and absence of quantum confinement effects.

Structure and photoluminescence properties of Ag-coated ZnO nano-needles

International Nuclear Information System (INIS)

Li Xiaozhu; Wang Yongqian

2011-01-01

Highlights: → ZnO nano-needles were synthesized by thermal oxidation. → Their surfaces were coated with Ag by pulse electro-deposition technique. → The uncoated and coated ZnO nano-needles were characterized. → The results showed that the prepared ZnO nano-needles have been coated with Ag successfully. → The photoluminescence spectrums of ZnO nano-needles with Ag-coated and uncoated were analyzed, finding that the Ag-coated ZnO nano-needles can increase the absorption of UV light. - Abstract: A large number of zinc oxide (ZnO) nano-needles were synthesized by thermal oxidation of pure zinc. The surfaces of ZnO nano-needles were coated with a layer of Ag by pulse electro-deposition technique. The uncoated and coated ZnO nano-needles were characterized by using the X-ray diffraction and the scanning electron microscope (SEM). The results showed that the uncoated samples were close-packed hexagonal structure, which showed needle-like morphology. Their average diameter is about 40 nm, lengths up to 5 μm. At the same time we observed that the prepared ZnO nano-needles have been coated with Ag successfully. The photoluminescence spectrums of ZnO nano-needles with Ag-coated and uncoated were analyzed, finding that the uncoated ZnO nano-needles have two fluorescence peaks at 388 nm and 470.8 nm, respectively, the relative intensity of 143.4 and 93.61; and the Ag-coated ZnO nano-needles showed a pair of strong peaks at 387.4 nm and 405.2 nm, the relative intensity of 1366 and 1305, respectively, indicating that the Ag-coated ZnO nano-needles can increase the absorption of UV light.

A universal DNA-based protein detection system.

Science.gov (United States)

Tran, Thua N N; Cui, Jinhui; Hartman, Mark R; Peng, Songming; Funabashi, Hisakage; Duan, Faping; Yang, Dayong; March, John C; Lis, John T; Cui, Haixin; Luo, Dan

2013-09-25

Protein immune detection requires secondary antibodies which must be carefully selected in order to avoid interspecies cross-reactivity, and is therefore restricted by the limited availability of primary/secondary antibody pairs. Here we present a versatile DNA-based protein detection system using a universal adapter to interface between IgG antibodies and DNA-modified reporter molecules. As a demonstration of this capability, we successfully used DNA nano-barcodes, quantum dots, and horseradish peroxidase enzyme to detect multiple proteins using our DNA-based labeling system. Our system not only eliminates secondary antibodies but also serves as a novel method platform for protein detection with modularity, high capacity, and multiplexed capability.

Genome Partitioner: A web tool for multi-level partitioning of large-scale DNA constructs for synthetic biology applications.

Science.gov (United States)

Christen, Matthias; Del Medico, Luca; Christen, Heinz; Christen, Beat

2017-01-01

Recent advances in lower-cost DNA synthesis techniques have enabled new innovations in the field of synthetic biology. Still, efficient design and higher-order assembly of genome-scale DNA constructs remains a labor-intensive process. Given the complexity, computer assisted design tools that fragment large DNA sequences into fabricable DNA blocks are needed to pave the way towards streamlined assembly of biological systems. Here, we present the Genome Partitioner software implemented as a web-based interface that permits multi-level partitioning of genome-scale DNA designs. Without the need for specialized computing skills, biologists can submit their DNA designs to a fully automated pipeline that generates the optimal retrosynthetic route for higher-order DNA assembly. To test the algorithm, we partitioned a 783 kb Caulobacter crescentus genome design. We validated the partitioning strategy by assembling a 20 kb test segment encompassing a difficult to synthesize DNA sequence. Successful assembly from 1 kb subblocks into the 20 kb segment highlights the effectiveness of the Genome Partitioner for reducing synthesis costs and timelines for higher-order DNA assembly. The Genome Partitioner is broadly applicable to translate DNA designs into ready to order sequences that can be assembled with standardized protocols, thus offering new opportunities to harness the diversity of microbial genomes for synthetic biology applications. The Genome Partitioner web tool can be accessed at https://christenlab.ethz.ch/GenomePartitioner.

Genome Partitioner: A web tool for multi-level partitioning of large-scale DNA constructs for synthetic biology applications.

Directory of Open Access Journals (Sweden)

Matthias Christen

Full Text Available Recent advances in lower-cost DNA synthesis techniques have enabled new innovations in the field of synthetic biology. Still, efficient design and higher-order assembly of genome-scale DNA constructs remains a labor-intensive process. Given the complexity, computer assisted design tools that fragment large DNA sequences into fabricable DNA blocks are needed to pave the way towards streamlined assembly of biological systems. Here, we present the Genome Partitioner software implemented as a web-based interface that permits multi-level partitioning of genome-scale DNA designs. Without the need for specialized computing skills, biologists can submit their DNA designs to a fully automated pipeline that generates the optimal retrosynthetic route for higher-order DNA assembly. To test the algorithm, we partitioned a 783 kb Caulobacter crescentus genome design. We validated the partitioning strategy by assembling a 20 kb test segment encompassing a difficult to synthesize DNA sequence. Successful assembly from 1 kb subblocks into the 20 kb segment highlights the effectiveness of the Genome Partitioner for reducing synthesis costs and timelines for higher-order DNA assembly. The Genome Partitioner is broadly applicable to translate DNA designs into ready to order sequences that can be assembled with standardized protocols, thus offering new opportunities to harness the diversity of microbial genomes for synthetic biology applications. The Genome Partitioner web tool can be accessed at https://christenlab.ethz.ch/GenomePartitioner.

Defining Nano, Nanotechnology and Nanomedicine: Why Should It Matter?

OpenAIRE

Satalkar Priya; Elger Bernice Simone; Shaw David M

2016-01-01

Nanotechnology which involves manipulation of matter on a 'nano' scale is considered to be a key enabling technology. Medical applications of nanotechnology (commonly known as nanomedicine) are expected to significantly improve disease diagnostic and therapeutic modalities and subsequently reduce health care costs. However there is no consensus on the definition of nanotechnology or nanomedicine and this stems from the underlying debate on defining 'nano'. This paper aims to present the diver...

Nano-scale Biophysical and Structural Investigations on Intact and Neuropathic Nerve Fibers by Simultaneous Combination of Atomic Force and Confocal Microscopy

Directory of Open Access Journals (Sweden)

Gonzalo Rosso

2017-08-01

Full Text Available The links between neuropathies of the peripheral nervous system (PNS, including Charcot-Marie-Tooth1A and hereditary neuropathy with liability to pressure palsies, and impaired biomechanical and structural integrity of PNS nerves remain poorly understood despite the medical urgency. Here, we present a protocol describing simultaneous structural and biomechanical integrity investigations on isolated nerve fibers, the building blocks of nerves. Nerve fibers are prepared from nerves harvested from wild-type and exemplary PNS neuropathy mouse models. The basic principle of the designed experimental approach is based on the simultaneous combination of atomic force microscopy (AFM and confocal microscopy. AFM is used to visualize the surface structure of nerve fibers at nano-scale resolution. The simultaneous combination of AFM and confocal microscopy is used to perform biomechanical, structural, and functional integrity measurements at nano- to micro-scale. Isolation of sciatic nerves and subsequent teasing of nerve fibers take ~45 min. Teased fibers can be maintained at 37°C in a culture medium and kept viable for up to 6 h allowing considerable time for all measurements which require 3–4 h. The approach is designed to be widely applicable for nerve fibers from mice of any PNS neuropathy. It can be extended to human nerve biopsies.

Progress in Nano-Electro-Optics III Industrial Applications and Dynamics of the Nano-Optical System

CERN Document Server

Ohtsu, Motoichi

2005-01-01

This unique monograph series "Progress in Nano-Electro Optics" reviews the results of advanced studies of electro-optics on the nanometric scale. This third volume covers the most recent topics of theoretical and experimental interest including classical and quantum optics, organic and inorganic material science and technology, surface science, spectroscopy, atom manipulation, photonics, and electronics. Each chapter is written by one or more leading scientists from the relevant field. Thus, high-quality scientific and technical information is provided to scientists, engineers, and students engaged in nano-electro optics and nanophotonics research. The first two volumes addressed the "Basics and Theory of Near Field Optics" (2002) and "Novel Devices and Atom Manipulation" (2003).

Complementary techniques for solid oxide cell characterisation on micro- and nano-scale

International Nuclear Information System (INIS)

Wiedenmann, D.; Hauch, A.; Grobety, B.; Mogensen, M.; Vogt, U.

2009-01-01

High temperature steam electrolysis by solid oxide electrolysis cells (SOEC) is a way with great potential to transform clean and renewable energy from non-fossil sources to synthetic fuels such as hydrogen, methane or dimethyl ether, which have been identified as promising alternative energy carriers. Also, as SOEC can operate in the reverse mode as solid oxide fuel cells (SOFC), during high peak hours e.g. hydrogen can be used in a very efficient way to reconvert chemically stored energy into electrical energy. As solid oxide cells (SOC) are working at high temperatures (700-900 o C), material degradation and evaporation can occur e.g. from the cell sealing material, leading to poisoning effects and aging mechanisms which are decreasing the cell efficiency and long-term durability. In order to investigate such cell degradation processes, thorough examination on SOC often requires the chemical and structural characterisation on the microscopic and the nanoscopic level. The combination of different microscope techniques like conventional scanning electron microscopy (SEM), electron-probe microanalysis (EPMA) and the focused ion-beam (FIB) preparation technique for transmission electron microscopy (TEM) allows performing post mortem analysis on a multi scale level of cells after testing. These complementary techniques can be used to characterize structural and chemical changes over a large and representative sample area (micro-scale) on the one hand, and also on the nano-scale level for selected sample details on the other hand. This article presents a methodical approach for the structural and chemical characterisation of changes in aged cathode-supported electrolysis cells produced at Riso DTU, Denmark. Also, results from the characterisation of impurities at the electrolyte/hydrogen interface caused by evaporation from sealing material are discussed. (author)

Replication Fidelity Assessment in Nano Moulding

DEFF Research Database (Denmark)

Calaon, Matteo; Hansen, Hans Nørgaard; Tosello, Guido

2015-01-01

to remove technology barrier between lab-scale proof-of-principle and high-volume low-cost production of nanotechnology-based products. In the current study research work has been devoted to develop methods and approaches to process chain characterization for final polymer micro and nano structures...

On the efficient warm white-light emission from nano-sized Y{sub 2}O{sub 3}