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Sample records for htpem-based micro combined

  1. FUEL CELL/MICRO-TURBINE COMBINED CYCLE

    SciTech Connect

    Larry J. Chaney; Mike R. Tharp; Tom W. Wolf; Tim A. Fuller; Joe J. Hartvigson

    1999-12-01

    A wide variety of conceptual design studies have been conducted that describe ultra-high efficiency fossil power plant cycles. The most promising of these ultra-high efficiency cycles incorporate high temperature fuel cells with a gas turbine. Combining fuel cells with a gas turbine increases overall cycle efficiency while reducing per kilowatt emissions. This study has demonstrated that the unique approach taken to combining a fuel cell and gas turbine has both technical and economic merit. The approach used in this study eliminates most of the gas turbine integration problems associated with hybrid fuel cell turbine systems. By using a micro-turbine, and a non-pressurized fuel cell the total system size (kW) and complexity has been reduced substantially from those presented in other studies, while maintaining over 70% efficiency. The reduced system size can be particularly attractive in the deregulated electrical generation/distribution environment where the market may not demand multi-megawatt central stations systems. The small size also opens up the niche markets to this high efficiency, low emission electrical generation option.

  2. Flexible intramuscular micro tube electrode combining electrical and chemical interface.

    PubMed

    Tian, Hong-Chang; Liu, Jing-Quan; Du, Jing-Cheng; Kang, Xiao-Yang; Zhang, Chuan; Yang, Bin; Chen, Xiang; Yang, Chun-Sheng

    2014-01-01

    With the rapidly developed micromachining technology, various kinds of sophisticated microelectrodes integrated with micro fluidic channels are design and fabricated for not only electrophysiological recording and stimulation, but also chemical drug delivery. As many efforts have been devoted to develop rigid microprobes for neural research of brain, few researchers concentrate on fabrication of flexible microelectrodes for intramuscular electrophysiology and chemical interfacing. Since crude wire electrodes still prevail in functional electrical stimulation (FES) and electromyography (EMG) recording of muscle, here we introduce a flexible micro tube electrode combining electrical and chemical pathway. The proposed micro tube electrode is manufactured based on polymer capillary, which provide circumferential electrode site contacting with electro-active tissue and is easy to manufactured with low cost.

  3. Micro-tubular flame-assisted fuel cells for micro-combined heat and power systems

    NASA Astrophysics Data System (ADS)

    Milcarek, Ryan J.; Wang, Kang; Falkenstein-Smith, Ryan L.; Ahn, Jeongmin

    2016-02-01

    Currently the role of fuel cells in future power generation is being examined, tested and discussed. However, implementing systems is more difficult because of sealing challenges, slow start-up and complex thermal management and fuel processing. A novel furnace system with a flame-assisted fuel cell is proposed that combines the thermal management and fuel processing systems by utilizing fuel-rich combustion. In addition, the flame-assisted fuel cell furnace is a micro-combined heat and power system, which can produce electricity for homes or businesses, providing resilience during power disruption while still providing heat. A micro-tubular solid oxide fuel cell achieves a significant performance of 430 mW cm-2 operating in a model fuel-rich exhaust stream.

  4. Combined Micro-chemical and Micro-structural Analysis of New Minerals Representing Extreme Conditions

    NASA Astrophysics Data System (ADS)

    Ma, C.; Tschauner, O. D.

    2015-12-01

    Recent improvements in micro-chemical analysis in combination with novel tools for micrometer-scale structural analysis of minerals from synchrotron X-ray diffraction open a pathway towards studies of mineral paragenesis that were previously not or barely accessible. Often mineral assemblies that represent extreme conditions also pose extreme challenges to analysis: very small size scale, complex matrix, minor amounts of material. Examples of such extreme, but also quite relevant environments are: a) High pressure shock-metamorphic minerals in meteorites and terrestrial impact sites, b) inclusions in diamonds from the deep mantle, c) ultrarefractory phases in Ca-Al-inlcusions from the solar nebula, d) presolar condensates. We show how a combination of synchrotron-based structural and semi-quantitative chemical techniques, with electron-microscopy based high-resolution imaging and fully quantitative chemical analysis and qualitative structural identification establish a powerful tool for discovery and characterization of important and interesting new minerals on micron- to submicron size scale.

  5. Combined nano- and micro-scale topographic cues for engineered vascular constructs by electrospinning and imprinted micro-patterns.

    PubMed

    Moffa, Maria; Sciancalepore, Anna Giovanna; Passione, Laura Gioia; Pisignano, Dario

    2014-06-25

    The major cause of synthetic vessel failure is thrombus and neointima formation. To prevent these problems the creation of a continuous and elongated endothelium inside lumen vascular grafts might be a promising solution for tissue engineering. Different micro- and nano-surface topographic cues including grooved micro-patterns and electrospun fibers have been previously demonstrated to guide the uniform alignment of endothelial cells (ECs). Here, with a very simple and highly versatile approach we combined electrospinning with soft lithography to fabricate nanofibrous scaffolds with oriented fibers modulated by different micro-grooved topographies. The effect of these scaffolds on the behavior of the ECs are analyzed, including their elongation, spreading, proliferation, and functioning using unpatterned random and aligned nanofibers (NFs) as controls. It is demonstrated that both aligned NFs and micro-patterns effectively influence the cellular response, and that a proper combination of topographic parameters, exploiting the synergistic effects of micro-scale and sub-micrometer features, can promote EC elongation, allowing the creation of a confluent ECs monolayer in analogy with the natural endothelium as assessed by the positive expression of vinculin. Combining different micro- and nano-topographic cues by complementary soft patterning and spinning technologies could open interesting perspectives for engineered vascular replacement constructions.

  6. Combined nano- and micro-scale topographic cues for engineered vascular constructs by electrospinning and imprinted micro-patterns.

    PubMed

    Moffa, Maria; Sciancalepore, Anna Giovanna; Passione, Laura Gioia; Pisignano, Dario

    2014-06-25

    The major cause of synthetic vessel failure is thrombus and neointima formation. To prevent these problems the creation of a continuous and elongated endothelium inside lumen vascular grafts might be a promising solution for tissue engineering. Different micro- and nano-surface topographic cues including grooved micro-patterns and electrospun fibers have been previously demonstrated to guide the uniform alignment of endothelial cells (ECs). Here, with a very simple and highly versatile approach we combined electrospinning with soft lithography to fabricate nanofibrous scaffolds with oriented fibers modulated by different micro-grooved topographies. The effect of these scaffolds on the behavior of the ECs are analyzed, including their elongation, spreading, proliferation, and functioning using unpatterned random and aligned nanofibers (NFs) as controls. It is demonstrated that both aligned NFs and micro-patterns effectively influence the cellular response, and that a proper combination of topographic parameters, exploiting the synergistic effects of micro-scale and sub-micrometer features, can promote EC elongation, allowing the creation of a confluent ECs monolayer in analogy with the natural endothelium as assessed by the positive expression of vinculin. Combining different micro- and nano-topographic cues by complementary soft patterning and spinning technologies could open interesting perspectives for engineered vascular replacement constructions. PMID:24623539

  7. Laser and focused ion beam combined machining for micro dies.

    PubMed

    Yoshida, Y; Okazaki, W; Uchida, T

    2012-02-01

    We have developed a laser and focused ion beam (FIB) compound process for press mold dies of a micro lens array (MLA) and a micro needle array (MNA) in a glassy carbon (GC). The press mold die of the MLA was roughly fabricated by UV-YAG laser. After this process, we finished this surface by scanning FIB. As a result, higher accuracy and good roughness of surface profile can be realized. An optical glass is used to confirm the shape of lens. Moreover, we fabricated 6 × 6 through-holes in the GC by the spiral drilling in addition to the focus position movement of the UV laser for press mold die of the MNA. After the FIB process, we were able to make the needle die of surface and hole wall roughness less than 0.9 μm. A silicon rubber is used to confirm the shape of the holes.

  8. [Development of Sediment Micro-Interface Under Physical and Chironomus plumosus Combination Disturbance].

    PubMed

    Wang, Ren; Li, Da-peng; Huang, Yong; Liu, Yan-jian; Chen, Jun

    2015-11-01

    Synergistic effect of physical and Chironomus plumosus combination disturbance on the characteristics of the micro-environment and micro-interface was investigated by the Rhizon samplers and Unisense micro sensor system. The results showed that the oxygen penetration depth (OPD), total oxygen exchange (TOE), water content and total microbial activity increased under the combination disturbance and bioturbation and were kept at the higher level, compared with the control. These parameters increased with the physical intensity under combination disturbance. However, the content of Fe2+ decreased under the combination disturbance and bioturbation and the decrease was more obvious than that in the control. The changes of the Fe2+, the water content and the total microbial activity were large at 0-4 cm depth in the sediments. Therefore, the area might be the active area for the transformation of internal sedimentary phosphorus forms. The curve fitting was used for the OPD, TOE, the content of Fe2+, the water content and the total microbial activity with the physical intensity under combination disturbance. It was observed that the second-order polynomial equation was suitable for the curve fitting. In addition, jump type synergistic effect was presented in the above mentioned parameters under combination disturbance when the physical intensity was higher than 34 r x min(-1). The remodeling on the sediment micro-interface and micro-environment might be the main inducing mechanism for the transformation of internal phosphorus. PMID:26910997

  9. Versatile atomic force microscopy setup combined with micro-focused X-ray beam

    SciTech Connect

    Slobodskyy, T. Tholapi, R.; Liefeith, L.; Hansen, W.; Zozulya, A. V. Fester, M.; Sprung, M.

    2015-06-15

    Micro-focused X-ray beams produced by third generation synchrotron sources offer new perspective of studying strains and processes at nanoscale. Atomic force microscope setup combined with a micro-focused synchrotron beam allows precise positioning and nanomanipulation of nanostructures under illumination. In this paper, we report on integration of a portable commercial atomic force microscope setup into a hard X-ray synchrotron beamline. Details of design, sample alignment procedure, and performance of the setup are presented.

  10. Dynamic micro-bead arrays using optical tweezers combined with intelligent control techniques.

    PubMed

    Tanaka, Yoshio; Kawada, Hiroyuki; Tsutsui, Shogo; Ishikawa, Mitsuru; Kitajima, Hiroyuki

    2009-12-21

    Dynamic micro-bead arrays offer great flexibility and potential as sensing tools in various scientific fields. Here we present a software-oriented approach for fully automated assembly of versatile dynamic micro-bead arrays using multi-beam optical tweezers combined with intelligent control techniques. Four typical examples, including the collision-free sorting of array elements by bead features, are demonstrated in real time. Control algorithms and experimental apparatus for these demonstrations are also described.

  11. Evaluation of coating adhesion using a radial speckle interferometer combined with a micro-indentation test

    NASA Astrophysics Data System (ADS)

    Tendela, Lucas P.; Kaufmann, Guillermo H.

    2012-06-01

    This paper presents a technique to investigate coating adhesion which combines a radial in-plane speckle interferometer and a micro-indentation test. The proposed technique is based on the measurement of the radial in-plane displacement field produced by a micro-indentation introduced on the coated surface of the specimen. Using steel specimens coated with a thin coating of epoxy paint and subjected to different adhesive conditions, it is demonstrated that digital speckle pattern interferometry can be successfully used to measure the small local deformations generated by a micro-indentation. An empirical model, which allows to quantify the adhesion of a given coated-substrate system by the proposed combined technique, is finally presented.

  12. IR image properties measurement of new micro-mirror array structure beam combiner

    NASA Astrophysics Data System (ADS)

    Li, Yanhong; Zhang, Li; Li, Zhuo

    2014-11-01

    Microwave (MW)/Infrared(IR) dual-mode compound guidance technology has greatly developed recent years for enhancing guidance precision effectively. Here a new micro-mirror array structure is introduced as upright display for MW/IR beam combiner in HWIL simulation. The beam combiner is used in the IR/MW compound HWIL system for transmitting the MW signal while reflecting the IR signal. The spatial resolution and spatial uniformity are two important performance indicators for beam combiner in the application of HWIL simulation system. In this paper, the definitions, measurement methods, and results of spatial resolution and spatial uniformity are given. Through the measurement by multiple groups of black and white stripes, the spatial resolution and the spatial uniformity can be got. It shows the micro-mirror array beam combiner can be applied for MW/IR dual-mode common-aperture HWIL simulation system.

  13. Environmental Technology Verification Report: Climate Energy freewatt™ Micro-Combined Heat and Power System

    EPA Science Inventory

    The EPA GHG Center collaborated with the New York State Energy Research and Development Authority (NYSERDA) to evaluate the performance of the Climate Energy freewatt Micro-Combined Heat and Power System. The system is a reciprocating internal combustion (IC) engine distributed e...

  14. Combination of nonlinear ultrasonics and guided wave tomography for imaging the micro-defects.

    PubMed

    Li, Weibin; Cho, Younho

    2016-02-01

    The use of guided wave tomography has become an attractive alternative to convert ultrasonic wave raw data to visualized results for quantitative signal interpretation. For more accurate life prediction and efficient management strategies for critical structural components, there is a demand of imaging micro-damages in early stage. However, there is rarely investigation on guided wave tomographic imaging of micro-defects. One of the reasons for this might be that it becomes challenging to monitor tiny signal difference coefficient in a reliable manner for wave propagation in the specimens with micro-damages. Nonlinear acoustic signal whose frequency differs from that of the input signal can be found in the specimens with micro-damages. Therefore, the combination of guided wave tomography and nonlinear acoustic response induced by micro-damages could be a feasibility study for imaging micro-damages. In this paper, the nonlinear Rayleigh surface wave tomographic method is investigated to locate and size micro-corrosive defect region in an isotropic solid media. The variations of acoustic nonlinear responses of ultrasonic waves in the specimens with and without defects are used in guided wave tomographic algorithm to construct the images. The comparisons between images obtained by experimental signals and real defect region induced by hydrogen corrosion are presented in this paper. Results show that the images of defect regions with different shape, size and location are successfully obtained by this novel technique, while there is no visualized result constructed by conventional linear ultrasonic tomographic one. The present approach shows a potential for inspecting, locating and imaging micro-defects by nonlinear Rayleigh surface wave tomography.

  15. MicroRNA Imaging in Combination with Diagnostic Ultrasound and Bubble Liposomes for MicroRNA Delivery.

    PubMed

    Endo-Takahashi, Yoko; Negishi, Yoichi; Suzuki, Ryo; Maruyama, Kazuo; Aramaki, Yukihiko

    2016-01-01

    MicroRNA (miRNA) is expected to play an important role in the diagnosis and therapy of various diseases. In miRNA therapy, the development of delivery tools to the target site is considered to be essential. By using a delivery tool possessing imaging ability, miRNA colocalized with the carrier could be visualized after administration. We prepared polyethylene glycol (PEG)-modified liposomes containing echo-contrast gas, "Bubble liposomes" (BLs), and confirmed that BLs containing cationic lipid were capable of loading miRNA. Furthermore, we also achieved the imaging and delivery of systemically injected miRNA to target site in combination with ultrasound exposure. MiRNA-loaded BLs could be a useful tool for imaging and therapy.

  16. Development of a combined microSPECT/CT system for small animal imaging

    NASA Astrophysics Data System (ADS)

    Sun, Mingshan

    Modern advances in the biomedical sciences have placed increased attention on small animals such as mice and rats as models of human biology and disease in biological research and pharmaceutical development. Their small size and fast breeding rate, their physiologic similarity to human, and, more importantly, the availability of sophisticated genetic manipulations, all have made mice and rats the laboratory mammals of choice in these experimental studies. However, the increased use of small animals in biomedical research also calls for new instruments that can measure the anatomic and metabolic information noninvasively with adequate spatial resolution and measurement sensitivity to facilitate these studies. This dissertation describes the engineering development of a combined single photon emission computed tomography (SPECT) and X-ray computed tomography (CT) system dedicated for small animals imaging. The system aims to obtain both the anatomic and metabolic images with submillimeter spatial resolution in a way that the data can be correlated to provide improved image quality and to offer more complete biological evaluation for biomedical studies involving small animals. The project requires development of complete microSPECT and microCT subsystems. Both subsystems are configured with a shared gantry and animal bed with integrated instrumentation for data acquisition and system control. The microCT employs a microfocus X-ray tube and a CCD-based detector for low noise, high resolution imaging. The microSPECT utilizes three semiconductor detectors coupled with pinhole collimators. A significant contribution of this dissertation project is the development of iterative algorithms with geometrical compensation that allows radionuclide images to be reconstructed at submillimeter spatial resolution, but with significantly higher detection efficiency than conventional methods. Both subsystems are capable of helical scans, offering lengthened field of view and improved

  17. Unified field analysis method for IR/MW micro-mirror array beam combiner.

    PubMed

    Tian, Yi; Sun, Gang; Yan, Hui; Zhang, Li; Li, Zhuo

    2014-07-01

    The aperture field integration method (AFIM) is proposed and utilized to efficiently compute the field distributions of infrared/microwave (IR/MW) micro-mirror array beam combiners, including the MW near-field distribution and the IR far-field distribution. The MW near-field distributions of single-dielectric-layer beam combiners with 1, 11, and 101 micromirrors are analyzed by AFIM. Compared to the commonly used multilevel fast multipole method (MLFMM) in the computation of MW near-field distribution, the memory requirement and CPU time consumption are reduced drastically from 16.92 GB and 3.26 h to 0.66 MB and 0.55 s, respectively. The calculation accuracy is better than 96%, when the MW near-field distribution is computed. The IR far-field computational capability is validated by comparing the results obtained through AFIM and experiment. The MW near field and IR far field of a circular and a square shape of three-layer micro-mirror array beam combiners are also analyzed. Four indicators E pv , E rms , φ pv , and φ rms representing the amplitude and phase variations are proposed to evaluate the MW near-field uniformity. The simulation results show that the increase of beam combiner size can improve the uniformity of the MW near field, and that the square shape has less influence on the uniformity of the MW near field than the circular one. The zeroth-order diffraction primary maximum intensity of the IR far field is decreased by 1/cos 2  α 0 times compared to that of the equivalent mirror, where α 0 is the oblique angle of each micromirror. When the periodic length of the micro-mirror array is less than 0.1 mm, the position of the secondary maximum will exceed the size of the focal plane array. Simultaneously, the half-width of the zeroth-order diffraction primary maximum is less than the size of a single pixel. Thus, IR images with high quality will be obtained. The simulation results show that the AFIM as a unified method can be applied to design

  18. Business Case for a Micro-Combined Heat and Power Fuel Cell System in Commercial Applications

    SciTech Connect

    Brooks, Kriston P.; Makhmalbaf, Atefe; Anderson, David M.; Amaya, Jodi P.; Pilli, Siva Prasad; Srivastava, Viraj; Upton, Jaki F.

    2013-10-30

    Combined heat and power fuel cell systems (CHP-FCSs) provide consistent electrical power and hot water with greater efficiency and lower emissions than alternative sources. These systems can be used either as baseload, grid-connected, or as off-the-grid power sources. This report presents a business case for CHP-FCSs in the range of 5 to 50 kWe. Systems in this power range are considered micro-CHP-FCS. For this particular business case, commercial applications rather than residential or industrial are targeted. To understand the benefits of implementing a micro-CHP-FCS, the characteristics that determine their competitive advantage must first be identified. Locations with high electricity prices and low natural gas prices are ideal locations for micro-CHP-FCSs. Fortunately, these high spark spread locations are generally in the northeastern area of the United States and California where government incentives are already in place to offset the current high cost of the micro-CHP-FCSs. As a result of the inherently high efficiency of a fuel cell and their ability to use the waste heat that is generated as a CHP, they have higher efficiency. This results in lower fuel costs than comparable alternative small-scale power systems (e.g., microturbines and reciprocating engines). A variety of markets should consider micro-CHP-FCSs including those that require both heat and baseload electricity throughout the year. In addition, the reliable power of micro-CHP-FCSs could be beneficial to markets where electrical outages are especially frequent or costly. Greenhouse gas emission levels from micro-CHP-FCSs are 69 percent lower, and the human health costs are 99.9 percent lower, than those attributed to conventional coal-fired power plants. As a result, FCSs can allow a company to advertise as environmentally conscious and provide a bottom-line sales advantage. As a new technology in the early stages of adoption, micro-CHP-FCSs are currently more expensive than alternative

  19. Combined UV/vis and micro-tomography investigation of acetaminophen dissolution from granules.

    PubMed

    Kašpar, Ondřej; Tokárová, Viola; Oka, Sarang; Sowrirajan, Koushik; Ramachandran, Rohit; Štěpánek, František

    2013-12-31

    The X-ray micro-tomography (micro-CT) technique has been used to visualize the microstructure of granules produced by high shear wet granulation and the dynamic evolution of porosity during granule dissolution. Using acetaminophen (paracetamol) as the active pharmaceutical ingredient (API) and microcrystalline cellulose (Avicel PH-200) as an excipient, the porosity of the granules was systematically influenced by the granulation process parameters (binder/solids ratio, impeller speed and wet massing time). An increase of granule porosity from 7% to 10% and 18% lead to a decrease of the dissolution time t90 from 435 min to 98 min and 37 min, respectively. The combination of time-resolved micro-CT imaging with UV/vis detection of the quantity dissolved made it possible to evaluate the effective diffusion coefficient of the API through the granule structure, and thus establish a quantitative structure–property relationship for dissolution. A power-law dependence of the effective diffusivity on porosity (Archie's law) was found to hold. PMID:24409518

  20. Combined UV/Vis and micro-tomography investigation of acetaminophen dissolution from granules.

    PubMed

    Kašpar, Ondřej; Tokárová, Viola; Oka, Sarang; Sowrirajan, Koushik; Ramachandran, Rohit; Stěpánek, František

    2013-10-24

    The x-ray micro-tomography (micro-CT) technique has been used to visualize the microstructure of granules produced by high shear wet granulation and the dynamic evolution of porosity during granule dissolution. Using acetaminophen (paracetamol) as the active pharmaceutical ingredient (API) and microcrystalline cellulose (Avicel PH-200) as an excipient, the porosity of the granules was systematically influenced by the granulation process parameters (binder/solids ratio, impeller speed and wet massing time). An increase of granule porosity from 7% to 10% and 18% lead to a decrease of the dissolution time t90 from 435min to 98min and 37min, respectively. The combination of time-resolved micro-CT imaging with UV/VIS detection of the quantity dissolved made it possible to evaluate the effective diffusion coefficient of the API through the granule structure, and thus establish a quantitative structure-property relationship for dissolution. A power-law dependence of the effective diffusivity on porosity (Archie's law) was found to hold. PMID:24513549

  1. Endothelial cell colonization and angiogenic potential of combined nano- and micro-fibrous scaffolds for bone tissue engineering.

    PubMed

    Santos, Marina I; Tuzlakoglu, Kadriye; Fuchs, Sabine; Gomes, Manuela E; Peters, Kirsten; Unger, Ronald E; Piskin, Erhan; Reis, Rui L; Kirkpatrick, C James

    2008-11-01

    Presently the majority of tissue engineering approaches aimed at regenerating bone relies only on post-implantation vascularization. Strategies that include seeding endothelial cells (ECs) on biomaterials and promoting their adhesion, migration and functionality might be a solution for the formation of vascularized bone. Nano/micro-fiber-combined scaffolds have an innovative structure, inspired by extracellular matrix (ECM) that combines a nano-network, aimed to promote cell adhesion, with a micro-fiber mesh that provides the mechanical support. In this work we addressed the influence of this nano-network on growth pattern, morphology, inflammatory expression profile, expression of structural proteins, homotypic interactions and angiogenic potential of human EC cultured on a scaffold made of a blend of starch and poly(caprolactone). The nano-network allowed cells to span between individual micro-fibers and influenced cell morphology. Furthermore, on nano-fibers as well as on micro-fibers ECs maintained the physiological expression pattern of the structural protein vimentin and PECAM-1 between adjacent cells. In addition, ECs growing on the nano/micro-fiber-combined scaffold were sensitive to pro-inflammatory stimulus. Under pro-angiogenic conditions in vitro, the ECM-like nano-network provided the structural and organizational stability for ECs' migration and organization into capillary-like structures. The architecture of nano/micro-fiber-combined scaffolds elicited and guided the 3D distribution of ECs without compromising the structural requirements for bone regeneration.

  2. Measuring the mechanical properties of plant cells by combining micro-indentation with osmotic treatments

    PubMed Central

    Weber, Alain; Braybrook, Siobhan; Huflejt, Michal; Mosca, Gabriella; Routier-Kierzkowska, Anne-Lise; Smith, Richard S.

    2015-01-01

    Growth in plants results from the interaction between genetic and signalling networks and the mechanical properties of cells and tissues. There has been a recent resurgence in research directed at understanding the mechanical aspects of growth, and their feedback on genetic regulation. This has been driven in part by the development of new micro-indentation techniques to measure the mechanical properties of plant cells in vivo. However, the interpretation of indentation experiments remains a challenge, since the force measures results from a combination of turgor pressure, cell wall stiffness, and cell and indenter geometry. In order to interpret the measurements, an accurate mechanical model of the experiment is required. Here, we used a plant cell system with a simple geometry, Nicotiana tabacum Bright Yellow-2 (BY-2) cells, to examine the sensitivity of micro-indentation to a variety of mechanical and experimental parameters. Using a finite-element mechanical model, we found that, for indentations of a few microns on turgid cells, the measurements were mostly sensitive to turgor pressure and the radius of the cell, and not to the exact indenter shape or elastic properties of the cell wall. By complementing indentation experiments with osmotic experiments to measure the elastic strain in turgid cells, we could fit the model to both turgor pressure and cell wall elasticity. This allowed us to interpret apparent stiffness values in terms of meaningful physical parameters that are relevant for morphogenesis. PMID:25873663

  3. Measuring the mechanical properties of plant cells by combining micro-indentation with osmotic treatments.

    PubMed

    Weber, Alain; Braybrook, Siobhan; Huflejt, Michal; Mosca, Gabriella; Routier-Kierzkowska, Anne-Lise; Smith, Richard S

    2015-06-01

    Growth in plants results from the interaction between genetic and signalling networks and the mechanical properties of cells and tissues. There has been a recent resurgence in research directed at understanding the mechanical aspects of growth, and their feedback on genetic regulation. This has been driven in part by the development of new micro-indentation techniques to measure the mechanical properties of plant cells in vivo. However, the interpretation of indentation experiments remains a challenge, since the force measures results from a combination of turgor pressure, cell wall stiffness, and cell and indenter geometry. In order to interpret the measurements, an accurate mechanical model of the experiment is required. Here, we used a plant cell system with a simple geometry, Nicotiana tabacum Bright Yellow-2 (BY-2) cells, to examine the sensitivity of micro-indentation to a variety of mechanical and experimental parameters. Using a finite-element mechanical model, we found that, for indentations of a few microns on turgid cells, the measurements were mostly sensitive to turgor pressure and the radius of the cell, and not to the exact indenter shape or elastic properties of the cell wall. By complementing indentation experiments with osmotic experiments to measure the elastic strain in turgid cells, we could fit the model to both turgor pressure and cell wall elasticity. This allowed us to interpret apparent stiffness values in terms of meaningful physical parameters that are relevant for morphogenesis.

  4. MicroRNAs Used in Combination with Anti-Cancer Treatments Can Enhance Therapy Efficacy

    PubMed Central

    Mognato, Maddalena; Celotti, Lucia

    2015-01-01

    MicroRNAs (miRNAs), a recently discovered class of small non-coding RNAs, constitute a promising approach to anti-cancer treatments when they are used in combination with other agents. MiRNAs are evolutionarily conserved non-coding RNAs that negatively regulate gene expression by binding to the complementary sequence in the 3’-untranslated region (UTR) of target genes. MiRNAs typically suppress gene expression by direct association with target transcripts, thus decreasing the expression levels of target proteins. The delivery to cells of synthetic miRNAs that mimic endogenous miRNA targeting genes involved in the DNA-Damage Response (DDR) can perturb the process, making cells more sensitive to chemotherapy or radiotherapy. This review examines how cells respond to combined therapy and it provides insights into the role of miRNAs in targeting the DDR repair pathway when they are used in combination with chemical compounds or ionizing radiation to enhance cellular sensitivity to treatments. PMID:26156420

  5. A methodology for understanding the impacts of large-scale penetration of micro-combined heat and power

    SciTech Connect

    Tapia-Ahumada, K.; Pérez-Arriaga, I. J.; Moniz, Ernest J.

    2013-10-01

    Co-generation at small kW-e scale has been stimulated in recent years by governments and energy regulators as one way to increasing energy efficiency and reducing CO2emissions. If a widespread adoption should be realized, their effects from a system's point of view are crucial to understand the contributions of this technology. Based on a methodology that uses long-term capacity planning expansion, this paper explores some of the implications for an electric power system of having a large number of micro-CHPs. Results show that fuel cells-based micro-CHPs have the best and most consistent performance for different residential demands from the customer and system's perspectives. As the penetration increases at important levels, gas-based technologies - particularly combined cycle units - are displaced in capacity and production, which impacts the operation of the electric system during summer peak hours. Other results suggest that the tariff design impacts the economic efficiency of the system and the operation of micro-CHPs under a price-based strategy. Finally, policies aimed at micro-CHPs should consider the suitability of the technology (in size and heat-to-power ratio) to meet individual demands, the operational complexities of a large penetration, and the adequacy of the economic signals to incentivize an efficient and sustainable operation. Highlights: Capacity displacements and daily operation of an electric power system are explored; Benefits depend on energy mix, prices, and micro-CHP technology and control scheme; Benefits are observed mostly in winter when micro-CHP heat and power are fully used; Micro-CHPs mostly displace installed capacity from natural gas combined cycle units; and, Tariff design impacts economic efficiency of the system and operation of micro-CHPs.

  6. Theragnosis-based combined cancer therapy using doxorubicin-conjugated microRNA-221 molecular beacon.

    PubMed

    Lee, Jonghwan; Choi, Kyung-Ju; Moon, Sung Ung; Kim, Soonhag

    2016-01-01

    Recently, microRNA (miRNA or miR) has emerged as a new cancer biomarker because of its high expression level in various cancer types and its role in the control of tumor suppressor genes. In cancer studies, molecular imaging and treatment based on target cancer markers have been combined to facilitate simultaneous cancer diagnosis and therapy. In this study, for combined therapy with diagnosis of cancer, we developed a doxorubicin-conjugated miR-221 molecular beacon (miR-221 DOXO MB) in a single platform composed of three different nucleotides: miR-221 binding sequence, black hole quencher 1 (BHQ1), and doxorubicin binding site. Imaging of endogenous miR-221 was achieved by specific hybridization between miR-221 and the miR-221 binding site in miR-221 DOXO MB. The presence of miR-221 triggered detachment of the quencher oligo and subsequent activation of a fluorescent signal of miR-221 DOXO MB. Simultaneous cancer therapy in C6 astrocytoma cells and nude mice was achieved by inhibition of miRNA-221 function that downregulates tumor suppressor genes. The detection of miR-221 expression and inhibition of miR-221 function by miR-221 DOXO MB provide the feasibility as a cancer theragnostic probe. Furthermore, a cytotoxic effect was induced by unloading of doxorubicin intercalated into miR-221 DOXO MB inside cells. Loss of miR-221 function and cytotoxicity induced by the miR-221 DOXO MB provides combined therapeutic efficacy against cancers. This method could be used as a new theragnostic probe with enhanced therapy to detect and inhibit many cancer-related miRNAs.

  7. Theragnosis-based combined cancer therapy using doxorubicin-conjugated microRNA-221 molecular beacon.

    PubMed

    Lee, Jonghwan; Choi, Kyung-Ju; Moon, Sung Ung; Kim, Soonhag

    2016-01-01

    Recently, microRNA (miRNA or miR) has emerged as a new cancer biomarker because of its high expression level in various cancer types and its role in the control of tumor suppressor genes. In cancer studies, molecular imaging and treatment based on target cancer markers have been combined to facilitate simultaneous cancer diagnosis and therapy. In this study, for combined therapy with diagnosis of cancer, we developed a doxorubicin-conjugated miR-221 molecular beacon (miR-221 DOXO MB) in a single platform composed of three different nucleotides: miR-221 binding sequence, black hole quencher 1 (BHQ1), and doxorubicin binding site. Imaging of endogenous miR-221 was achieved by specific hybridization between miR-221 and the miR-221 binding site in miR-221 DOXO MB. The presence of miR-221 triggered detachment of the quencher oligo and subsequent activation of a fluorescent signal of miR-221 DOXO MB. Simultaneous cancer therapy in C6 astrocytoma cells and nude mice was achieved by inhibition of miRNA-221 function that downregulates tumor suppressor genes. The detection of miR-221 expression and inhibition of miR-221 function by miR-221 DOXO MB provide the feasibility as a cancer theragnostic probe. Furthermore, a cytotoxic effect was induced by unloading of doxorubicin intercalated into miR-221 DOXO MB inside cells. Loss of miR-221 function and cytotoxicity induced by the miR-221 DOXO MB provides combined therapeutic efficacy against cancers. This method could be used as a new theragnostic probe with enhanced therapy to detect and inhibit many cancer-related miRNAs. PMID:26454049

  8. Micro- and nanoscale structures of mesiodens dentin: Combined study of FTIR and SAXS/WAXS techniques.

    PubMed

    Akgun, Ozlem Marti; Bayari, Sevgi Haman; Ide, Semra; Polat, Günseli Guven; Kalkhoran, Ilghar Orujalipoor

    2015-01-01

    A mesiodens is the most common type of supernumerary tooth present in conjunction to normal dentition. A mesiodens may commonly occur in the central region of the upper or lower jaw. A mesiodens is different from normal teeth in terms of structure and shape. The aim of this study is to evaluate the micro- and nanoscale structural properties of mesiodens dentin by combined small- and wide-angle X-ray scattering (SAXS/WAXS) and Fourier transform infrared (FTIR) spectroscopy. Five freshly extracted, noncarious mesiodens and five normal dentin disks prepared from human incisor teeth were compared. Using FTIR, the phosphate-to-amide I, carbonate-to-phosphate, and carbonate-to-amide I band area ratios and the crystallinity index were quantified. SAXS/WAXS were used to study the nanostructure of mesiodens. An increase in the mineral content in the mesiodens dentin with respect to the normal group was found. Crystallinity was also significantly increased and the protein content decreased in the mesiodens dentin compared with that of normal dentin. SAXS/WAXS results revealed that mesiodens dentin has a more calcified tissue. Further, SAXS analysis revealed a nonuniform distribution of dentin fibrils in mesiodens.

  9. Modeling the Dynamics of Micro- and Macroparticles in a Combined Gas-Discharge Installation

    NASA Astrophysics Data System (ADS)

    Astashinskii, V. V.; Bogach, M. I.; Burachevskii, A. V.

    2016-05-01

    We present a model of the dynamics of micro- and macroparticles in a combined gas-discharge installation that accounts for the processes of metal explosion (heating of a metal in its solid state, melting, heating of the liquid metal, intense evaporation, ionization in metal vapor), a magnetohydrodynamic description of plasma acceleration (on the basis of the mass, momentum, and energy conservation laws neglecting the plasma viscosity and thermal conductivity), and a description of the processes of energy transfer from a high-velocity stream to accelerated particles. It has been established that the process of melting terminates in 1.3 ns after the start of the discharge and that the evaporation terminates in 480 ns. The stage of cooling starts in 21 μs. The average density of the plasma upon completion of the evaporation process can be estimated to be 1.7·10-5 g/cm3, with the pressure being of the order of 1.5·104 Pa and the total time of discharge, of about 250 μs.

  10. A new approach for combining knowledge from multiple coexpression networks of microRNAs.

    PubMed

    Bhattacharyya, Malay; Das, Manali; Bandyopadhyay, Sanghamitra

    2013-08-01

    MicroRNAs (miRNAs) are a class of small noncoding RNAs that are known to have critical functions across various biological processes. Simultaneous activities of multiple miRNAs can be monitored from their expression profiles under various conditions. We often build up coexpression networks from such profiles. Unfortunately, due to the change of experimental setups (or conditions), the expression profiles do change, and consequently, the patterns of the coexpression networks vary. To obtain a robust functional relationship between miRNAs, by integrating different coexpression networks in a systems biology approach, we have to combine them properly. Here, we evaluate the state-of-the-art techniques and propose a novel integrative measure, and a corresponding methodology, that might be useful for identifying the dependence between coexpression and functional similarity. We establish the results by evaluating the expression profiles of miRNAs taken from bone marrow samples of patients with leukemia. The findings highlight the potential of the integrative algorithm in analyzing the expression profiles of miRNAs for further study.

  11. Atomic force microscope with combined FTIR-Raman spectroscopy having a micro thermal analyzer

    DOEpatents

    Fink, Samuel D.; Fondeur, Fernando F.

    2011-10-18

    An atomic force microscope is provided that includes a micro thermal analyzer with a tip. The micro thermal analyzer is configured for obtaining topographical data from a sample. A raman spectrometer is included and is configured for use in obtaining chemical data from the sample.

  12. Towards near-permanent CoCrMo prosthesis surface by combining micro-texturing and low temperature plasma carburising.

    PubMed

    Dong, Yangchun; Svoboda, Petr; Vrbka, Martin; Kostal, David; Urban, Filip; Cizek, Jan; Roupcova, Pavla; Dong, Hanshan; Krupka, Ivan; Hartl, Martin

    2015-03-01

    An advanced surface engineering process combining micro-texture with a plasma carburising process was produced on CoCrMo femoral head, and their tribological properties were evaluated by the cutting-edge pendulum hip joint simulator coupled with thin film colorimetric interferometry. FESEM and GDOES showed that precipitation-free C S-phase with a uniform case depth of 10μm was formed across the micro-textures after duplex treatment. Hip simulator tests showed that the friction coefficient was reduced by 20% for micro-metre sized texture, and the long-term tribological property of microtexture was enhanced by the C-supersaturated crystalline microstructure formed on the surface of duplex treated CoCrMo, thereby enhancing biotribological durability significantly. In-situ colorimetric interferometry confirmed that the maximum film thickness around texture area was 530nm, indicating that the additional lubricant during sliding motion might provide exceptional bearing life. PMID:26594781

  13. Advanced combined application of micro-X-ray diffraction/micro-X-ray fluorescence with conventional techniques for the identification of pictorial materials from Baroque Andalusia paintings.

    PubMed

    Herrera, L K; Montalbani, S; Chiavari, G; Cotte, M; Solé, V A; Bueno, J; Duran, A; Justo, A; Perez-Rodriguez, J L

    2009-11-15

    The process of investigating paintings includes the identification of materials to solve technical and historical art questions, to aid in the deduction of the original appearance, and in the establishment of the chemical and physical conditions for adequate restoration and conservation. In particular, we have focused on the identification of several samples taken from six famous canvases painted by Pedro Atanasio Bocanegra, who created a very special collection depicting the life of San Ignacio, which is located in the church of San Justo y Pastor of Granada, Spain. The characterization of the inorganic and organic compounds of the textiles, preparation layers, and pictorial layers have been carried out using an XRD diffractometer, SEM observations, EDX spectrometry, FT-IR spectrometry (both in reflection and transmission mode), pyrolysis/gas chromatography/mass spectrometry and synchrotron-based micro-X-ray techniques. In this work, the advantages over conventional X-ray diffraction of using combined synchrotron-based micro-X-ray diffraction and micro-X-ray fluorescence in the identification of multi-layer paintings is demonstrated. PMID:19782194

  14. An all-silicon single-wafer micro-g accelerometer with a combined surface and bulk micromachining process

    NASA Technical Reports Server (NTRS)

    Yazdi, N.; Najafi, K.

    2000-01-01

    This paper reports an all-silicon fully symmetrical z-axis micro-g accelerometer that is fabricated on a single-silicon wafer using a combined surface and bulk fabrication process. The microaccelerometer has high device sensitivity, low noise, and low/controllable damping that are the key factors for attaining micro g and sub-micro g resolution in capacitive accelerometers. The microfabrication process produces a large proof mass by using the whole wafer thickness and a large sense capacitance by utilizing a thin sacrificial layer. The sense/feedback electrodes are formed by a deposited 2-3 microns polysilicon film with embedded 25-35 microns-thick vertical stiffeners. These electrodes, while thin, are made very stiff by the thick embedded stiffeners so that force rebalancing of the proof mass becomes possible. The polysilicon electrodes are patterned to create damping holes. The microaccelerometers are batch-fabricated, packaged, and tested successfully. A device with a 2-mm x 1-mm proof mass and a full bridge support has a measured sensitivity of 2 pF/g. The measured sensitivity of a 4-mm x 1-mm accelerometer with a cantilever support is 19.4 pF/g. The calculated noise floor of these devices at atmosphere are 0.23 micro g/sqrt(Hz) and 0.16 micro g/sqrt(Hz), respectively.

  15. Combined micro computed tomography and histology study of bone augmentation and distraction osteogenesis

    NASA Astrophysics Data System (ADS)

    Ilgenstein, Bernd; Deyhle, Hans; Jaquiery, Claude; Kunz, Christoph; Stalder, Anja; Stübinger, Stefan; Jundt, Gernot; Beckmann, Felix; Müller, Bert; Hieber, Simone E.

    2012-10-01

    Bone augmentation is a vital part of surgical interventions of the oral and maxillofacial area including dental implantology. Prior to implant placement, sufficient bone volume is needed to reduce the risk of peri-implantitis. While augmentation using harvested autologous bone is still considered as gold standard, many surgeons prefer bone substitutes to reduce operation time and to avoid donor site morbidity. To assess the osteogenic efficacy of commercially available augmentation materials we analyzed drill cores extracted before implant insertion. In younger patients, distraction osteogenesis is successfully applied to correct craniofacial deformities through targeted bone formation. To study the influence of mesenchymal stem cells on bone regeneration during distraction osteogenesis, human mesenchymal stem cells were injected into the distraction gap of nude rat mandibles immediately after osteotomy. The distraction was performed over eleven days to reach a distraction gap of 6 mm. Both the rat mandibles and the drill cores were scanned using synchrotron radiation-based micro computed tomography. The three-dimensional data were manually registered and compared with corresponding two-dimensional histological sections to assess bone regeneration and its morphology. The analysis of the rat mandibles indicates that bone formation is enhanced by mesenchymal stem cells injected before distraction. The bone substitutes yielded a wide range of bone volume and degree of resorption. The volume fraction of the newly formed bone was determined to 34.4% in the computed tomography dataset for the augmentation material Geistlich Bio-Oss®. The combination of computed tomography and histology allowed a complementary assessment for both bone augmentation and distraction osteogenesis.

  16. Near-infrared confocal micro-Raman spectroscopy combined with PCA-LDA multivariate analysis for detection of esophageal cancer

    NASA Astrophysics Data System (ADS)

    Chen, Long; Wang, Yue; Liu, Nenrong; Lin, Duo; Weng, Cuncheng; Zhang, Jixue; Zhu, Lihuan; Chen, Weisheng; Chen, Rong; Feng, Shangyuan

    2013-06-01

    The diagnostic capability of using tissue intrinsic micro-Raman signals to obtain biochemical information from human esophageal tissue is presented in this paper. Near-infrared micro-Raman spectroscopy combined with multivariate analysis was applied for discrimination of esophageal cancer tissue from normal tissue samples. Micro-Raman spectroscopy measurements were performed on 54 esophageal cancer tissues and 55 normal tissues in the 400-1750 cm-1 range. The mean Raman spectra showed significant differences between the two groups. Tentative assignments of the Raman bands in the measured tissue spectra suggested some changes in protein structure, a decrease in the relative amount of lactose, and increases in the percentages of tryptophan, collagen and phenylalanine content in esophageal cancer tissue as compared to those of a normal subject. The diagnostic algorithms based on principal component analysis (PCA) and linear discriminate analysis (LDA) achieved a diagnostic sensitivity of 87.0% and specificity of 70.9% for separating cancer from normal esophageal tissue samples. The result demonstrated that near-infrared micro-Raman spectroscopy combined with PCA-LDA analysis could be an effective and sensitive tool for identification of esophageal cancer.

  17. Nitrogen removal in micro-polluted surface water by the combined process of bio-filter and ecological gravel bed.

    PubMed

    Sheng-Bing, He; Jian-Wen, Gao; Xue-Chu, Chen; Ding-Li, Dai

    2013-01-01

    Nitrogen removal in micro-polluted surface water by the combined process of a bio-filter and an ecological gravel bed was studied. Sodium acetate was added into micro-polluted surface water as carbon source and the nitrogen removal under different C/N ratio, hydraulic load and temperature were investigated. The results showed that the variations in C/N ratio, hydraulic load and temperature have significant influence on nitrogen removal in bio-filter. It was found that the denitrification rate was above 90% when C/N ratio reached 10; also, the denitrification was inhibited at low water temperature (2-10 °C); at the condition of water temperature above 20 °C, C/N ratio 10, hydraulic load 8 m(3)/(m(2) h), the combined process obtained the nitrogen removal of more than 90%, and the residual organics could be removed in ecological gravel bed.

  18. Synthesis and characterization of hybrid micro/nano-structured NiTi surfaces by a combination of etching and anodizing.

    PubMed

    Huan, Z; Fratila-Apachitei, L E; Apachitei, I; Duszczyk, J

    2014-02-01

    The purpose of this study was to generate hybrid micro/nano-structures on biomedical nickel-titanium alloy (NiTi). To achieve this, NiTi surfaces were firstly electrochemically etched and then anodized in fluoride-containing electrolyte. With the etching process, the NiTi surface was micro-roughened through the formation of micropits uniformly distributed over the entire surface. Following the subsequent anodizing process, self-organized nanotube structures enriched in TiO2 could be superimposed on the etched surface under specific conditions. Furthermore, the anodizing treatment significantly reduced water contact angles and increased the surface free energy compared to the surfaces prior to anodizing. The results of this study show for the first time that it is possible to create hybrid micro/nano-structures on biomedical NiTi alloys by combining electrochemical etching and anodizing under controlled conditions. These novel structures are expected to significantly enhance the surface biofunctionality of the material when compared to conventional implant devices with either micro- or nano-structured surfaces.

  19. Synthesis and adsorption performance of lead ion-imprinted micro-beads with combination of two functional monomers.

    PubMed

    Zhu, Linyan; Zhu, Zhiliang; Zhang, Ronghua; Hong, Jun; Qiu, Yanling

    2011-01-01

    A novel ion-imprinted polymer, lead ion-imprinted micro-beads with combination of two functional monomers, was synthesized using the W/O/W polymerization method. Two functional monomers, 1,12-dodecanediol-O,O'-diphenyl-phosphonic acid (DDDPA) and 4-vinylpyridine, were used to form a suitable construction with micro-pores fitting the template and recognition sites. The effects of adsorbent dosage, solution pH and the competitive ions on the adsorption and separation efficiency of lead ions were investigated. The lead ion-imprinted micro-beads were efficient for lead ions removal from aqueous solution in a broad pH range (4-9), when the adsorbent dosage was above 0.1 g/L. The adsorption process obeyed the pseudo second-order kinetics model and it only took half an hour to reach the equilibrium. The adsorption isotherm of lead ion was described by the Langmuir model (R2 > 0.99) with a maximum adsorption capacity of 116.9 mg/g. In the presence of competitive ions Co2+ and Cd2+, the lead ion-imprinted micro-beads showed a high selectivity for lead ions. The selectivity coefficient of Pb2+/Cd2+ and Pb2+/Co2+ are 99.3 and 114.7, respectively. PMID:22432324

  20. Synthesis and adsorption performance of lead ion-imprinted micro-beads with combination of two functional monomers.

    PubMed

    Zhu, Linyan; Zhu, Zhiliang; Zhang, Ronghua; Hong, Jun; Qiu, Yanling

    2011-01-01

    A novel ion-imprinted polymer, lead ion-imprinted micro-beads with combination of two functional monomers, was synthesized using the W/O/W polymerization method. Two functional monomers, 1,12-dodecanediol-O,O'-diphenyl-phosphonic acid (DDDPA) and 4-vinylpyridine, were used to form a suitable construction with micro-pores fitting the template and recognition sites. The effects of adsorbent dosage, solution pH and the competitive ions on the adsorption and separation efficiency of lead ions were investigated. The lead ion-imprinted micro-beads were efficient for lead ions removal from aqueous solution in a broad pH range (4-9), when the adsorbent dosage was above 0.1 g/L. The adsorption process obeyed the pseudo second-order kinetics model and it only took half an hour to reach the equilibrium. The adsorption isotherm of lead ion was described by the Langmuir model (R2 > 0.99) with a maximum adsorption capacity of 116.9 mg/g. In the presence of competitive ions Co2+ and Cd2+, the lead ion-imprinted micro-beads showed a high selectivity for lead ions. The selectivity coefficient of Pb2+/Cd2+ and Pb2+/Co2+ are 99.3 and 114.7, respectively.

  1. Synthesis and characterization of hybrid micro/nano-structured NiTi surfaces by a combination of etching and anodizing

    NASA Astrophysics Data System (ADS)

    Huan, Z.; Fratila-Apachitei, L. E.; Apachitei, I.; Duszczyk, J.

    2014-02-01

    The purpose of this study was to generate hybrid micro/nano-structures on biomedical nickel-titanium alloy (NiTi). To achieve this, NiTi surfaces were firstly electrochemically etched and then anodized in fluoride-containing electrolyte. With the etching process, the NiTi surface was micro-roughened through the formation of micropits uniformly distributed over the entire surface. Following the subsequent anodizing process, self-organized nanotube structures enriched in TiO2 could be superimposed on the etched surface under specific conditions. Furthermore, the anodizing treatment significantly reduced water contact angles and increased the surface free energy compared to the surfaces prior to anodizing. The results of this study show for the first time that it is possible to create hybrid micro/nano-structures on biomedical NiTi alloys by combining electrochemical etching and anodizing under controlled conditions. These novel structures are expected to significantly enhance the surface biofunctionality of the material when compared to conventional implant devices with either micro- or nano-structured surfaces.

  2. Highly Tunable Complementary Micro/Submicro-Nanopatterned Surfaces Combining Block Copolymer Self-Assembly and Colloidal Lithography.

    PubMed

    Chang, Tongxin; Du, Binyang; Huang, Haiying; He, Tianbai

    2016-08-31

    Two kinds of large-area ordered and highly tunable micro/submicro-nanopatterned surfaces in a complementary manner were successfully fabricated by elaborately combining block copolymer self-assembly and colloidal lithography. Employing a monolayer of polystyrene (PS) colloidal spheres assembled on top as etching mask, polystyrene-block-poly(2-vinylpyridine) (PS-b-P2VP) or polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) micelle films were patterned into micro/submicro patches by plasma etching, which could be further transferred into micropatterned metal nanoarrays by subsequent metal precursor loading and a second plasma etching. On the other hand, micro/submicro-nanopatterns in a complementary manner were generated via preloading a metal precursor in initial micelle films before the assembly of PS colloidal spheres on top. Both kinds of micro/submicro-nanopatterns showed good fidelity at the micro/submicroscale and nanoscale; meanwhile, they could be flexibly tuned by the sample and processing parameters. Significantly, when the PS colloidal sphere size was reduced to 250 nm, a high-resolution submicro-nanostructured surface with 3-5 metal nanoparticles in each patch or a single-nanoparticle interconnected honeycomb network was achieved. Moreover, by applying gold (Au) nanoparticles as anchoring points, micronanopatterned Au arrays can serve as a flexible template to pattern bovine serum albumin (BSA) molecules. This facile and cost-effective approach may provide a novel platform for fabrication of micropatterned nanoarrays with high tunability and controllability, which are promising in the applications of biological and microelectronic fields. PMID:27509255

  3. Combined influences of micro-pillar geometry and substrate constraint on microplastic behavior of compressed single-crystal micro-pillar: Two-dimensional discrete dislocation dynamics modeling

    NASA Astrophysics Data System (ADS)

    Ouyanga, Chaojun; Lia, Zhenhuan; Huanga, Minsheng; Hua, Lili; Houa, Chuantao

    2009-11-01

    2D discrete dislocation dynamic modeling of compressed micro-pillars attached on a huge base is executed to study the size-dependent microplastic behavior of micro-pillars and the corresponding size effect. In addition to the conventional dimensional parameters of the micro-pillar such as the micro-pillar size and the height-to-width ratio, the micro-pillar taper angle and the dislocation slip plane orientation angle in the micro-pillar are also considered to address the size effect and its rich underlying mechanism. Computational results show that there are at least two operating mechanisms responsible for the plastic behavior of micro-pillars. One is associated with the dislocation free slip-out from the micro-pillar sidewall; the other is related to the dislocation pile-up at the base and the top end of the pillar. The overall mechanism governing the size effect of the micro-pillar rests with multi-factors, including the micro-pillar size, the height-to-width ratio, the micro-pillar taper and the slip plane orientation angle; however, whether the "free slip band" exists or not is the most important denotation. The well-known Schmid law still validates in the slender micro-pillars due to existence of the free slip band, whereas it may fail in the podgier micro-pillars due to absence of the free slip band; as a result, a complicated even "reverse" size effect appears.

  4. Technical Analysis of Installed Micro-Combined Heat and Power Fuel-Cell System

    SciTech Connect

    Brooks, Kriston P.; Makhmalbaf, Atefe

    2014-10-31

    Combined heat and power fuel cell systems (CHP-FCSs) provide consistent electrical power and hot water with greater efficiency and lower emissions than alternative sources. These systems can be used either as baseload, grid-connected, or as off-the-grid power sources. This report presents a technical analysis of 5 kWe CHP-FCSs installed in different locations in the U.S. At some sites as many as five 5 kWe system is used to provide up to 25kWe of power. Systems in this power range are considered “micro”-CHP-FCS. To better assess performance of micro-CHP-FCS and understand their benefits, the U.S. Department of Energy worked with ClearEdge Power to install fifteen 5-kWe PBI high temperature PEM fuel cells (CE5 models) in the commercial markets of California and Oregon. Pacific Northwest National Laboratory evaluated these systems in terms of their economics, operations, and technical performance. These units were monitored from September 2011 until June 2013. During this time, about 190,000 hours of data were collected and more than 17 billion data points were analyzed. Beginning in July 2013, ten of these systems were gradually replaced with ungraded systems (M5 models) containing phosphoric acid fuel cell technology. The new units were monitored until June 2014 until they went offline because ClearEdge was bought by Doosan at the time and the new manufacturer did not continue to support data collection and maintenance of these units. During these two phases, data was collected at once per second and data analysis techniques were applied to understand behavior of these systems. The results of this analysis indicate that systems installed in the second phase of this demonstration performed much better in terms of availability, consistency in generation, and reliability. The average net electrical power output increased from 4.1 to 4.9 kWe, net heat recovery from 4.7 to 5.4 kWth, and system availability improved from 94% to 95%. The average net system electric

  5. Temporal synchronization and spectral combining of pulses from fiber lasers Q-switched by independent MEMS micro-mirrors.

    PubMed

    Fabert, Marc; Desfarges-Berthelemot, Agnès; Kermène, Vincent; Crunteanu, Aurelian

    2012-09-24

    We present what we believe to be the first demonstration of spectral combining of multiple fiber lasers Q-switched by independent micro-electro-mechanical system (MEMS). By correlating the actuation of the individual MEMS devices, the associated Q-switched lasers can be operated in either synchronous or asynchronous modes in such a way that their overall combined output may result in high energy emission pulses or in laser emission with higher pulse repetition rate. In a proof-of-principle experiment, we demonstrate the combination of four individual Q-switched lasers (each of them operating at 20 kHz repetition rate) leading to a final laser system generating pulses with a repetition rate of 80 kHz.

  6. A registration based approach for 4D cardiac micro-CT using combined prospective and retrospective gating

    PubMed Central

    Badea, Cristian T.; Schreibmann, Eduard; Fox, Tim

    2008-01-01

    Recent advances in murine cardiac studies with three-dimensional cone beam micro-computed tomography (CT) have used either prospective or retrospective gating technique. While prospective gating ensures the best image quality and the highest resolution, it involves longer sampling times and higher radiation dose. Sampling is faster and the radiation dose can be reduced with retrospective gating but the image quality is affected by the limited number of projections with an irregular angular distribution which complicate the reconstruction process, causing significant streaking artifacts. This work involves both prospective and retrospective gating in sampling. Deformable registration is used between a high quality image set acquired with prospective gating with the multiple data sets during the cardiac cycle obtained using retrospective gating. Tests were conducted on a four-dimensional (4D) cardiac mouse phantom and after optimization, the method was applied to in vivo cardiac micro-CT data. Results indicate that, by using our method, the sampling time can be reduced by a factor of 2.5 and the radiation dose can be reduced 35% compared to the prospective sampling while the image quality can be maintained. In conclusion, we proposed a novel solution to 4D cine cardiac micro-CT based on a combined prospective with retrospective gating in sampling and deformable registration post reconstruction that mixed the advantages of both strategies. PMID:18491508

  7. Combined simulation of a micro permanent magnetic linear contactless displacement sensor.

    PubMed

    Gao, Jing; Müller, Wolfgang F O; Greiner, Felix; Eicher, Dirk; Weiland, Thomas; Schlaak, Helmut F

    2010-01-01

    The permanent magnetic linear contactless displacement (PLCD) sensor is a new type of displacement sensor operating on the magnetic inductive principle. It has many excellent properties and has already been used for many applications. In this article a Micro-PLCD sensor which can be used for microelectromechanical system (MEMS) measurements is designed and simulated with the CST EM STUDIO(®) software, including building a virtual model, magnetostatic calculations, low frequency calculations, steady current calculations and thermal calculations. The influence of some important parameters such as air gap dimension, working frequency, coil current and eddy currents etc. is studied in depth.

  8. Combination of microRNA-21 and microRNA-146a Attenuates Cardiac Dysfunction and Apoptosis During Acute Myocardial Infarction in Mice

    PubMed Central

    Huang, Wei; Tian, Shan-Shan; Hang, Peng-Zhou; Sun, Chuan; Guo, Jing; Du, Zhi-Min

    2016-01-01

    Recent studies have revealed the cytoprotective roles of microRNAs (miRNAs) miR-21 and miR-146a against ischemic cardiac injuries. While these studies investigated each of these miRNAs as an independent individual factor, our previous study has suggested the possible interaction between these two miRNAs. The present study was designed to investigate this possibility by evaluating the effects of miR-21 and miR-146a combination on cardiac ischemic injuries and the underlying mechanisms. MiR-21 and miR-146a synergistically decreased apoptosis under ischemia/hypoxic conditions in cardiomyocytes compared with either miR-21 or miR-146a alone. Mice coinjected with agomiR-21 and agomiR-146a had decreased infarct size, increased ejection fraction (EF), and fractional shortening (FS). These effects were greater than those induced by either of the two agomiRs. Furthermore, greater decreases in p38 mitogen-associated protein kinase phosphorylation (p-p38 MAPK) were observed with miR-21: miR-146a combination as compared to application of either of the miRNAs. These data suggest that combination of miR-21 and miR-146a has a greater protective effect against cardiac ischemia/hypoxia-induced apoptosis as compared to these miRNAs applied individually. This synergistic action is mediated by enhanced potency of inhibition of cardiomyocyte apoptosis by the miR-21—PTEN/AKT—p-p38—caspase-3 and miR-146a—TRAF6—p-p38—caspase-3 signal pathways. PMID:26978580

  9. Design, Fabrication and Prototype testing of a Chip Integrated Micro PEM Fuel Cell Accumulator combined On-Board Range Extender

    NASA Astrophysics Data System (ADS)

    Balakrishnan, A.; Mueller, C.; Reinecke, H.

    2014-11-01

    In this work we present the design, fabrication and prototype testing of Chip Integrated Micro PEM Fuel Cell Accumulator (CIμ-PFCA) combined On-Board Range Extender (O-BRE). CIμ-PFCA is silicon based micro-PEM fuel cell system with an integrated hydrogen storage feature (palladium metal hydride), the run time of CIμ-PFCA is dependent on the stored hydrogen, and in order to extend its run time an O-BRE is realized (catalytic hydrolysis of chemical hydride, NaBH4. Combining the CIμ-PFCA and O-BRE on a system level have few important design requirements to be considered; hydrogen regulation, gas -liquid separator between the CIμ-PFCA and the O-RE. The usage of traditional techniques to regulate hydrogen (tubes), gas-liquid phase membranes (porous membrane separators) are less desirable in the micro domain, due to its space constraint. Our approach is to use a passive hydrogen regulation and gas-liquid phase separation concept; to use palladium membrane. Palladium regulates hydrogen by concentration diffusion, and its property to selectively adsorb only hydrogen is used as a passive gas-liquid phase separator. Proof of concept is shown by realizing a prototype system. The system is an assembly of CIμ-PFCA, palladium membrane and the O-BRE. The CIμ-PFCA consist of 2 individually processed silicon chips, copper supported palladium membrane realized by electroplating followed by high temperature annealing process under inter atmosphere and the O-BRE is realized out of a polymer substrate by micromilling process with platinum coated structures, which functions as a catalyst for the hydrolysis of NaBH4. The functionality of the assembled prototype system is demonstrated by the measuring a unit cell (area 1 mm2) when driven by the catalytic hydrolysis of chemical hydride (NaBH4 and the prototype system shows run time more than 15 hours.

  10. Micro-Bypass Implantation for Primary Open-Angle Glaucoma Combined with Phacoemulsification: 4-Year Follow-Up

    PubMed Central

    Fea, Antonio Maria; Consolandi, Giulia; Zola, Marta; Pignata, Giulia; Cannizzo, Paola; Lavia, Carlo; Rolle, Teresa; Grignolo, Federico Maria

    2015-01-01

    Purpose. To report the long-term follow-up results in patients with cataract and primary open-angle glaucoma (POAG) randomly assigned to cataract surgery combined with micro-bypass stent implantation or phacoemulsification alone. Methods. 36 subjects with cataract and POAG were randomized in a 1 : 2 ratio to either iStent implantation and cataract surgery (combined group) or cataract surgery alone (control group). 24 subjects agreed to be evaluated again 48 months after surgery. Patients returned one month later for unmedicated washout assessment. Results. At the long-term follow-up visit we reported a mean IOP of 15,9 ± 2,3 mmHg in the iStent group and 17 ± 2,5 mmHg in the control group (p = NS). After washout, a 14,2% between group difference in favour of the combined group was statistically significant (p = 0,02) for mean IOP reduction. A significant reduction in the mean number of medications was observed in both groups compared to baseline values (p = 0,005 in the combined group and p = 0,01 in the control group). Conclusion. Patients in the combined group maintained low IOP levels after long-term follow-up. Cataract surgery alone showed a loss of efficacy in controlling IOP over time. Both treatments reduced the number of ocular hypotensive medications prescribed. This trial is registered with: NCT00847158. PMID:26587282

  11. The effect of combined hypergravity and micro-grooved surface topography on the behaviour of fibroblasts.

    PubMed

    Loesberg, W A; Walboomers, X F; van Loon, J J W A; Jansen, J A

    2006-07-01

    This study evaluated in vitro the differences in morphological behaviour between fibroblast cultured on smooth and micro-grooved substrata (groove depth: 1 mum, width: 1, 2, 5, 10 microm), which undergo artificial hypergravity by centrifugation (10, 24 and 50 g; or 1 g control). The aim of the study was to clarify which of these parameters was more important to determine cell behaviour. Morphological characteristics were investigated using scanning electron microscopy and fluorescence microscopy in order to obtain qualitative information on cell spreading and alignment. Confocal laser scanning microscopy visualised distribution of actin filaments and vinculin anchoring points through immunostaining. Finally, expression of collagen type I, fibronectin, and alpha(1)- and beta(1)-integrin were investigated by PCR. Microscopy and image analysis showed that the fibroblasts aligned along the groove direction on all textured surfaces. On the smooth substrata (control), cells spread out in a random fashion. The alignment of cells cultured on grooved surfaces increased with higher g-forces until a peak value at 25 g. An ANOVA was performed on the data, for all main parameters: topography, gravity force, and time. In this analysis, all parameters proved significant. In addition, most gene levels were reduced by hypergravity. Still, collagen type 1 and fibronectin are seemingly unaffected by time or force. From our data it is concluded that the fibroblasts primarily adjust their shape according to morphological environmental cues like substratum surface whilst a secondary, but significant, role is played by hypergravity forces.

  12. END/MMOD: A Synergic Combination of a LEO Spacecraft Aero-Braking Deorbiting Module with a LEO Space Debris and Micro-Meteoroids Detection and Characterization System

    NASA Astrophysics Data System (ADS)

    Balduccini, Mauro; Raponi, Luca; Nascetti, Augusto; Bertini, Fabrizio; Gallucci, Stefano

    2013-08-01

    In this paper it is proposed the combination of the End-of-life Natural Deorbiting (END) module (an inflatable aerobreaking device already under development in AVIO and aimed to accelerate the orbital decay of inoperative spacecraft) with a sub-system called MMOD (Micro-Meteoroids and Orbital Debris) consisting of a hypervelocity impacts detector capable of collecting data relevant to the type and the distribution of space debris and micro-meteoroids in the LEO region.

  13. From particle to powder properties - A mesoscopic approach combining micro-scale experiments and X-ray microtomography

    NASA Astrophysics Data System (ADS)

    Strege, S.; Zetzener, H.; Kwade, A.

    2013-06-01

    The detailed understanding of particle flow is of special interest from the academic point of view and crucial for a safe and reliable process design. Due to poor flowability and heterogeneous bulk structures, the handling of fine and cohesive powders is particularly challenging. Recently, high resolution X-ray microtomography (XMT) has proved to be a reliable tool for analysing powder structures on bulk and particle level. This study now presents a complementary approach of micro-scale experiments and XMT analysis to improve the general understanding of particle flow. Centrepiece of the experimental investigation is a novel micro shear tester (μST) for very small powder samples (volumes from 0.005 to 0.1 mL), which has been integrated into a high resolution XMT system. By combining μST and XMT it is possible to extract detailed 3D images of precisely compacted and sheared powder samples. A SiO2 powder consisting of spherical, adhesive particles (x50,3 ≈ 11,2 μm) and a limestone powder consisting of irregular shaped particles (x50,3 ≈ 4,8 μm) are scanned before and after various shear and compaction tests. A detailed analysis of the sample microstructure reveals important information on the particle network and the bulk structure. The impact of the test procedure on mesoscopic heterogeneities and shear zones inside the sample is discussed. Moreover, the measurement of yield loci in the novel μST is presented.

  14. Microwave properties of polymer composites containing combinations of micro- and nano-sized magnetic fillers.

    PubMed

    Kolev, Svetoslav; Koutzarova, Tatyana; Yanev, Andrey; Ghelev, Chavdar; Nedkov, Ivan

    2008-02-01

    We investigated the microwave absorbing properties of composite bulk samples with nanostructured and micron-sized fillers. As magnetic fillers we used magnetite powder (Fe3O4 with low magnetocrystalline anisotropy) and strontium hexaferrite (SrFe12O9 with high magnetocrystalline anisotropy). The dielectric matrix consisted of silicone rubber. The average particle size was 30 nm for the magnetite powder and 6 micro/m for the strontium hexaferrite powder. The micron-sized SrFe12O19 powder was prepared using a solid-state reaction. We investigated the influence of the filler concentration and the filler ratio (Fe3O4/SrFe12O19) in the polymer matrix on the microwave absorption in a large frequency range (1 / 18 GHz). The results obtained showed that the highly anisotropic particles become centers of clusterification and the small magnetite particles form magnetic balls with different diameter depending on the concentration. The effect of adding micron-sized SrFe12O19 to the nanosized Fe3O4 filler in composites absorbing structures has to do with the ferromagnetic resonance (FMR) shifting to the higher frequencies due to the changes in the ferrite filler's properties induced by the presence of a magnetic material with high magnetocrystalline anisotropy. The two-component filler possesses new values of the saturation magnetization and of the anisotropy constant, differing from those of both SrFe12O1919 and Fe3O4, which leads to a rise in the effective anisotropy field. The results demonstrate the possibility to vary the composite's absorption characteristics in a controlled manner by way of introducing a second magnetic material. PMID:18464386

  15. Combination of powdered activated carbon and powdered zeolite for enhancing ammonium removal in micro-polluted raw water.

    PubMed

    Liao, Zhen-Liang; Chen, Hao; Zhu, Bai-Rong; Li, Huai-Zheng

    2015-09-01

    Even zeolite is promising in ammonia pollution disposing, its removal efficiency is frequently interfered by organics. As activated carbon has good removal efficiency on organic contaminants, combination of two adsorbents may allow their respective adsorption characteristics into full play. This paper provides a performance assessment of the combination for enhancing ammonium removal in micro-polluted raw water. Gel-filtration chromatography (GFC) was carried out to quantify the molecular weight (MW) range of organic contaminants that powdered activated carbon (PAC) and powdered zeolite (PZ) can remove. The polydispersity difference which also calculated from GFC may indicate the wider organic contaminants removal range of PAC and the relatively centralized removal range of PZ. The jar tests of combination dosing confirm a synergistic effect which promotes ammonium removing. Nevertheless, it also shows an antagonism hindering the due removal performance of the two adsorbents on CODMn, while it is not much evident on UV254. Furthermore, a comparison study with simulated coagulation-sedimentation process was conducted to evaluate the optimum dosing points (spatial and temporal) of PAC and PZ among follows: suction well, pipeline mixer, early and middle phase of flocculation. We suggest to dose both two adsorbents into the early phase of flocculation to maximize the versatile removal efficiency on turbidity, ammonium and organic contaminants.

  16. Combination of powdered activated carbon and powdered zeolite for enhancing ammonium removal in micro-polluted raw water.

    PubMed

    Liao, Zhen-Liang; Chen, Hao; Zhu, Bai-Rong; Li, Huai-Zheng

    2015-09-01

    Even zeolite is promising in ammonia pollution disposing, its removal efficiency is frequently interfered by organics. As activated carbon has good removal efficiency on organic contaminants, combination of two adsorbents may allow their respective adsorption characteristics into full play. This paper provides a performance assessment of the combination for enhancing ammonium removal in micro-polluted raw water. Gel-filtration chromatography (GFC) was carried out to quantify the molecular weight (MW) range of organic contaminants that powdered activated carbon (PAC) and powdered zeolite (PZ) can remove. The polydispersity difference which also calculated from GFC may indicate the wider organic contaminants removal range of PAC and the relatively centralized removal range of PZ. The jar tests of combination dosing confirm a synergistic effect which promotes ammonium removing. Nevertheless, it also shows an antagonism hindering the due removal performance of the two adsorbents on CODMn, while it is not much evident on UV254. Furthermore, a comparison study with simulated coagulation-sedimentation process was conducted to evaluate the optimum dosing points (spatial and temporal) of PAC and PZ among follows: suction well, pipeline mixer, early and middle phase of flocculation. We suggest to dose both two adsorbents into the early phase of flocculation to maximize the versatile removal efficiency on turbidity, ammonium and organic contaminants. PMID:25929873

  17. Outcomes of combined trabecular micro-bypass and phacoemulsification in a predominantly Hispanic patient population

    PubMed Central

    Gallardo, Mark J; Supnet, Richard A; Giamporcaro, Jane Ellen; Hornbeak, Dana M

    2016-01-01

    Purpose The purpose of this study was to evaluate intraocular pressure (IOP) and topical ocular hypotensive medication burden at 12 months postoperatively in a predominantly Hispanic patient population with primary open-angle glaucoma each implanted with one trabecular micro-bypass stent during cataract surgery. Methods This was a retrospective, consecutive case series. The main objective was to assess reduction of IOP and/or medication burden in all eyes at the 12-month postoperative exam. A secondary objective was to assess outcomes in 3 subgroups, distinguished preoperatively by IOP control and by medication burden (suboptimal or maximum therapy) and with different treatment goals. Group 1 had medication-controlled IOP and goal to reduce medications while maintaining IOP control (n=65); Group 2 had uncontrolled IOP on ≤2 medications and goal to reduce IOP and maintain/reduce medication burden (n=31); and Group 3 had uncontrolled IOP on ≥3 medications and goal to reduce IOP and avoid filtering surgery (n=38). Evaluations included IOP, medication use, cup-to-disc ratio, visual fields, complications, and interventions. One hundred subjects (134 eyes) have been followed for 12 months. Results Most patients (80%) were Hispanic and had moderate or severe glaucoma (87%). At 12 months, mean IOP reduced to 12.9 mmHg vs 16.5 mmHg preoperatively; 92% had an IOP ≤15 mmHg at 12 months (99% had ≤18 mmHg). Mean medication burden had decreased to 0.9 vs 2.3 preoperatively. At the 12-month time point, 94% of all eyes achieved their predefined treatment goal of reduced IOP and/or medications. Reductions in medication burden for Group 1, and in IOP for Groups 2 and 3, were highly statistically significant (P<0.001). Two eyes in Group 3 had filtering surgery; the remaining 95% avoided such treatment. No other complications were reported. Conclusion This mainly Hispanic population with predominantly moderate or severe glaucoma had substantial reduction of IOP and medication

  18. Combined micro-and standard percutaneous nephrolithotomy for complex renal calculi

    PubMed Central

    Buldu, İbrahim; Tepeler, Abdulkadir; Karatağ, Tuna; İnan, Ramazan; Armağan, Abdullah; İstanbulluoğlu, Okan

    2016-01-01

    Objective We aimed to present the technique of combination of standard percutaneous nephrolithotomy (PNL) with microperc for achieving higher success rates without increasing complication rates in the management of complex renal calculi. Material and methods The patients who underwent microperc procedure as a complementary procedure to standard PNL for complex kidney stones in two reference hospitals between 2013 and 2015, were evaluated retrospectively. Results All patients underwent a total of two accesses one for standard PNL and one for microperc. The mean stone size was measured as 54.3 mm. The procedures were completed after an average operative time of 88.2 minutes and fluoroscopy time of 5.3 minutes. Stone free status was achieved in 18 cases (78.2%) and small residual fragments (≤4 mm) were detected in 3 cases (13.1%). Complications were seen in three patients (13%) as hemorrhage in one and postoperative fever in two patients. Conclusion Despite the limitations of this study, the combination of standard PNL and microperc might reduce the complication rates and increase the success rates when treating complex kidney stones. Future prospective and comparative studies are needed. PMID:27635289

  19. Combined micro-and standard percutaneous nephrolithotomy for complex renal calculi

    PubMed Central

    Buldu, İbrahim; Tepeler, Abdulkadir; Karatağ, Tuna; İnan, Ramazan; Armağan, Abdullah; İstanbulluoğlu, Okan

    2016-01-01

    Objective We aimed to present the technique of combination of standard percutaneous nephrolithotomy (PNL) with microperc for achieving higher success rates without increasing complication rates in the management of complex renal calculi. Material and methods The patients who underwent microperc procedure as a complementary procedure to standard PNL for complex kidney stones in two reference hospitals between 2013 and 2015, were evaluated retrospectively. Results All patients underwent a total of two accesses one for standard PNL and one for microperc. The mean stone size was measured as 54.3 mm. The procedures were completed after an average operative time of 88.2 minutes and fluoroscopy time of 5.3 minutes. Stone free status was achieved in 18 cases (78.2%) and small residual fragments (≤4 mm) were detected in 3 cases (13.1%). Complications were seen in three patients (13%) as hemorrhage in one and postoperative fever in two patients. Conclusion Despite the limitations of this study, the combination of standard PNL and microperc might reduce the complication rates and increase the success rates when treating complex kidney stones. Future prospective and comparative studies are needed.

  20. A Combination of Transcriptional and MicroRNA Regulation Improves the Stability of the Relative Concentrations of Target Genes

    PubMed Central

    El Baroudi, Mariama; Ollino, Laura; Caselle, Michele

    2014-01-01

    It is well known that, under suitable conditions, microRNAs are able to fine tune the relative concentration of their targets to any desired value. We show that this function is particularly effective when one of the targets is a Transcription Factor (TF) which regulates the other targets. This combination defines a new class of feed-forward loops (FFLs) in which the microRNA plays the role of master regulator. Using both deterministic and stochastic equations, we show that these FFLs are indeed able not only to fine-tune the TF/target ratio to any desired value as a function of the miRNA concentration but also, thanks to the peculiar topology of the circuit, to ensure the stability of this ratio against stochastic fluctuations. These two effects are due to the interplay between the direct transcriptional regulation and the indirect TF/Target interaction due to competition of TF and target for miRNA binding (the so called “sponge effect”). We then perform a genome wide search of these FFLs in the human regulatory network and show that they are characterized by a very peculiar enrichment pattern. In particular, they are strongly enriched in all the situations in which the TF and its target have to be precisely kept at the same concentration notwithstanding the environmental noise. As an example we discuss the FFL involving E2F1 as Transcription Factor, RB1 as target and miR-17 family as master regulator. These FFLs ensure a tight control of the E2F/RB ratio which in turns ensures the stability of the transition from the G0/G1 to the S phase in quiescent cells. PMID:24586138

  1. Modelling and control synthesis of a micro-combined heat and power interface for a concentrating solar power system in off-grid rural power applications

    NASA Astrophysics Data System (ADS)

    Prinsloo, Gerro; Dobson, Robert; Brent, Alan; Mammoli, Andrea

    2016-05-01

    Concentrating solar power co-generation systems have been identified as potential stand-alone solar energy supply solutions in remote rural energy applications. This study describes the modelling and synthesis of a combined heat and power Stirling CSP system in order to evaluate its potential performance in small off-grid rural village applications in Africa. This Stirling micro-Combined Heat and Power (micro-CHP) system has a 1 kW electric capacity, with 3 kW of thermal generation capacity which is produced as waste heat recovered from the solar power generation process. As part of the development of an intelligent microgrid control and distribution solution, the Trinum micro-CHP system and other co-generation systems are systematically being modelled on the TRNSYS simulation platform. This paper describes the modelling and simulation of the Trinum micro-CHP configuration on TRNSYS as part of the process to develop the control automation solution for the smart rural microgrid in which the Trinum will serve as a solar powerpack. The results present simulated performance outputs for the Trinum micro-CHP system for a number of remote rural locations in Africa computed from real-time TRNSYS solar irradiation and weather data (yearly, monthly, daily) for the relevant locations. The focus of this paper is on the parametric modelling of the Trinum Stirling micro-CHP system, with specific reference to this system as a TRNSYS functional block in the microgrid simulation. The model is used to forecast the solar energy harvesting potential of the Trinum micro-CHP unit at a number of remote rural sites in Africa.

  2. Solid oxide fuel cell systems for residential micro-combined heat and power in the UK: Key economic drivers

    NASA Astrophysics Data System (ADS)

    Hawkes, Adam; Leach, Matthew

    The ability of combined heat and power (CHP) to meet residential heat and power demands efficiently offers potentially significant financial and environmental advantages over centralised power generation and heat-provision through natural-gas fired boilers. A solid oxide fuel cell (SOFC) can operate at high overall efficiencies (heat and power) of 80-90%, offering an improvement over centralised generation, which is often unable to utilise waste heat. This paper applies an equivalent annual cost (EAC) minimisation model to a residential solid oxide fuel cell CHP system to determine what the driving factors are behind investment in this technology. We explore the performance of a hypothetical SOFC system—representing expectations of near to medium term technology development—under present UK market conditions. We find that households with small to average energy demands do not benefit from installation of a SOFC micro-CHP system, but larger energy demands do benefit under these conditions. However, this result is sensitive to a number of factors including stack capital cost, energy import and export prices, and plant lifetime. The results for small and average dwellings are shown to reverse under an observed change in energy import prices, an increase in electricity export price, a decrease in stack capital costs, or an improvement in stack lifetime.

  3. Removal of nitrogen and phosphorus from the secondary effluent in tertiary denitrifying biofilters combined with micro-coagulation.

    PubMed

    Wei, Nan; Shi, Yunhong; Wu, Guangxue; Hu, Hongying; Guo, Yumei; Wu, Yihui; Wen, Hui

    2016-01-01

    Effective control of nitrogen and phosphorus in secondary effluent can reduce or avoid the eutrophication of receiving water bodies. Two denitrifying biofilters (DNBFs) packed with different sizes of quartz sands combined with micro-coagulation were operated for simultaneous removal of nitrogen and phosphorus from the secondary effluent. The quartz sand size in one DNBF was 2-4 mm (DNBFS), and in the other was 4-6 mm (DNBFL). In both DNBFs, methanol was used as the electron donor and different organic carbon to nitrogen (C/N) ratios were applied. Under C/N ratios of 1.5, 1.25, and 0.75 g/g, the nitrate nitrogen (NO3(-)-N) removal percentages were 73%, 77%, and 50% in DNBFS, and 43%, 25%, and 21% in DNBFL; the effluent total phosphorus concentrations were 0.15, 0.14, and 0.18 mg/L in DNBFS, and 0.29, 0.35, and 0.24 mg/L in DNBFL. The performance of both biofilters was quite stable within a backwashing cycle. The NO3(-)-N reduction rates were 1.31, 1.10, and 0.48 mg/(L·min) in DNBFS, and 0.97, 0.27, and 0.10 mg/(L·min) in DNBFL. For biomass detached from both biofilters, their denitrifying activities were similar. Biofilm biomass in DNBFS was higher than that in DNBFL, inducing a high denitrification efficiency in DNBFS.

  4. Removal of nitrogen and phosphorus from the secondary effluent in tertiary denitrifying biofilters combined with micro-coagulation.

    PubMed

    Wei, Nan; Shi, Yunhong; Wu, Guangxue; Hu, Hongying; Guo, Yumei; Wu, Yihui; Wen, Hui

    2016-01-01

    Effective control of nitrogen and phosphorus in secondary effluent can reduce or avoid the eutrophication of receiving water bodies. Two denitrifying biofilters (DNBFs) packed with different sizes of quartz sands combined with micro-coagulation were operated for simultaneous removal of nitrogen and phosphorus from the secondary effluent. The quartz sand size in one DNBF was 2-4 mm (DNBFS), and in the other was 4-6 mm (DNBFL). In both DNBFs, methanol was used as the electron donor and different organic carbon to nitrogen (C/N) ratios were applied. Under C/N ratios of 1.5, 1.25, and 0.75 g/g, the nitrate nitrogen (NO3(-)-N) removal percentages were 73%, 77%, and 50% in DNBFS, and 43%, 25%, and 21% in DNBFL; the effluent total phosphorus concentrations were 0.15, 0.14, and 0.18 mg/L in DNBFS, and 0.29, 0.35, and 0.24 mg/L in DNBFL. The performance of both biofilters was quite stable within a backwashing cycle. The NO3(-)-N reduction rates were 1.31, 1.10, and 0.48 mg/(L·min) in DNBFS, and 0.97, 0.27, and 0.10 mg/(L·min) in DNBFL. For biomass detached from both biofilters, their denitrifying activities were similar. Biofilm biomass in DNBFS was higher than that in DNBFL, inducing a high denitrification efficiency in DNBFS. PMID:27232413

  5. Longitudinal in vivo evaluation of bone regeneration by combined measurement of multi-pinhole SPECT and micro-CT for tissue engineering

    NASA Astrophysics Data System (ADS)

    Lienemann, Philipp S.; Metzger, Stéphanie; Kiveliö, Anna-Sofia; Blanc, Alain; Papageorgiou, Panagiota; Astolfo, Alberto; Pinzer, Bernd R.; Cinelli, Paolo; Weber, Franz E.; Schibli, Roger; Béhé, Martin; Ehrbar, Martin

    2015-05-01

    Over the last decades, great strides were made in the development of novel implants for the treatment of bone defects. The increasing versatility and complexity of these implant designs request for concurrent advances in means to assess in vivo the course of induced bone formation in preclinical models. Since its discovery, micro-computed tomography (micro-CT) has excelled as powerful high-resolution technique for non-invasive assessment of newly formed bone tissue. However, micro-CT fails to provide spatiotemporal information on biological processes ongoing during bone regeneration. Conversely, due to the versatile applicability and cost-effectiveness, single photon emission computed tomography (SPECT) would be an ideal technique for assessing such biological processes with high sensitivity and for nuclear imaging comparably high resolution (<1 mm). Herein, we employ modular designed poly(ethylene glycol)-based hydrogels that release bone morphogenetic protein to guide the healing of critical sized calvarial bone defects. By combined in vivo longitudinal multi-pinhole SPECT and micro-CT evaluations we determine the spatiotemporal course of bone formation and remodeling within this synthetic hydrogel implant. End point evaluations by high resolution micro-CT and histological evaluation confirm the value of this approach to follow and optimize bone-inducing biomaterials.

  6. Longitudinal in vivo evaluation of bone regeneration by combined measurement of multi-pinhole SPECT and micro-CT for tissue engineering

    PubMed Central

    Lienemann, Philipp S.; Metzger, Stéphanie; Kiveliö, Anna-Sofia; Blanc, Alain; Papageorgiou, Panagiota; Astolfo, Alberto; Pinzer, Bernd R.; Cinelli, Paolo; Weber, Franz E.; Schibli, Roger; Béhé, Martin; Ehrbar, Martin

    2015-01-01

    Over the last decades, great strides were made in the development of novel implants for the treatment of bone defects. The increasing versatility and complexity of these implant designs request for concurrent advances in means to assess in vivo the course of induced bone formation in preclinical models. Since its discovery, micro-computed tomography (micro-CT) has excelled as powerful high-resolution technique for non-invasive assessment of newly formed bone tissue. However, micro-CT fails to provide spatiotemporal information on biological processes ongoing during bone regeneration. Conversely, due to the versatile applicability and cost-effectiveness, single photon emission computed tomography (SPECT) would be an ideal technique for assessing such biological processes with high sensitivity and for nuclear imaging comparably high resolution (<1 mm). Herein, we employ modular designed poly(ethylene glycol)-based hydrogels that release bone morphogenetic protein to guide the healing of critical sized calvarial bone defects. By combined in vivo longitudinal multi-pinhole SPECT and micro-CT evaluations we determine the spatiotemporal course of bone formation and remodeling within this synthetic hydrogel implant. End point evaluations by high resolution micro-CT and histological evaluation confirm the value of this approach to follow and optimize bone-inducing biomaterials. PMID:25989250

  7. Effective elimination of organic matter interference in boron isotopic analysis by thermal ionization mass spectrometry of coral/foraminifera: micro-sublimation technology combined with ion exchange.

    PubMed

    He, Maoyong; Xiao, Yingkai; Ma, Yunqi; Jin, Zhangdong; Xiao, Jun

    2011-03-30

    In order to better estimate the effectiveness of micro-sublimation technology on the elimination of organic matter interference during boron isotopic analysis, a series of improved experiments was carried out using simple apparatus. Recovery rates after micro-sublimation were measured for boric acid solutions with different B contents or different B/organic matter ratios. The improved micro-sublimation procedure combined with ion-exchange technology was then used to test natural samples (coral and foraminifera) for the separation of boron. Our results show that the time taken for 100% recovery of different amounts of B differed and that the proportions of B/organic matter within the natural organic matter have little effect on the relationship between the recovery rates of B and the micro-sublimation times. The experiments further confirm that the organic matter does indeed have an effect on boron isotope analyses by positive thermal ionization mass spectrometry and that the use of micro-sublimation can effectively remove interferences from the organic matter during boron isotopic analysis. PMID:21337635

  8. Combination of Methods for the Fractionation, Investigation, and Analysis of Micro/Nano Particles in Volcanic Ash

    NASA Astrophysics Data System (ADS)

    Valeriy, Shkinev; Michail, Ermolin; Peter, Fedotov; Aleksander, Rudnev; Nikolay, Bulychev; Vitaliy, Linnik; Gerardo, Moreno

    2013-04-01

    Micro and nanoparticles play a very important role in environment, in biology and medicine, in various technologies. The investigation of particles is often based on the fractionation according to particle size, density and charge followed by the analysis of the separated fractions. Such studies are needed in the analysis of environmental samples (natural and waste waters, soils, sediments, ashes) to assess the soil formation processes as well as distribution, transport, and biological uptake of pollutants. Recently, the review dealing with the fractionation and investigation of particles in liquid media has been published [Anal. Bioanal. Chem., 2011, v. 400, no 6, p. 1787-1804]. The present report gives a brief overview of the state-of-the-art and describes some new methods, approaches, and devices developed in the Laboratory for Concentration Methods of Vernadsky Institute for the studies of volcanic ash samples. The ash is attributed to the volcanic activity of Cordón Caulle. Puyehue and Cordón Caulle (40°35'25″S -72°07'02″W) are two coalesced volcanic vents that form a major mountain massif in Puyehue National Park in the Andes of Ranco Province, Chile. In volcanology, this group is known under the name of Puyehue-Cordón Caulle Volcanic Complex. Four different volcanoes constitute the volcanic group or complex, the Cordillera Nevada caldera, the Pliocene Mencheca volcano, Cordón Caulle fissure vents, and the Puyehue stratovolcano. Most stratovolcanoes on the Southern Volcanic Zone of the Andes, Puyehue and Cordón Caulle are located along the intersection of traverse fault with the larger north-south Liquiñe-Ofqui Fault. A new eruption started on 04 June 2011. By 15 June a dense column of ash (9 km height) was still erupting into the air, with the ash cloud spreading across the Southern Hemisphere. Actually the volcano activity continues. The samples were collected before and after the acidic rain which occurred due to the release of sulfur gases

  9. Development of the dynamic motion simulator of 3D micro-gravity with a combined passive/active suspension system

    NASA Technical Reports Server (NTRS)

    Yoshida, Kazuya; Hirose, Shigeo; Ogawa, Tadashi

    1994-01-01

    The establishment of those in-orbit operations like 'Rendez-Vous/Docking' and 'Manipulator Berthing' with the assistance of robotics or autonomous control technology, is essential for the near future space programs. In order to study the control methods, develop the flight models, and verify how the system works, we need a tool or a testbed which enables us to simulate mechanically the micro-gravity environment. There have been many attempts to develop the micro-gravity testbeds, but once the simulation goes into the docking and berthing operation that involves mechanical contacts among multi bodies, the requirement becomes critical. A group at the Tokyo Institute of Technology has proposed a method that can simulate the 3D micro-gravity producing a smooth response to the impact phenomena with relatively simple apparatus. Recently the group carried out basic experiments successfully using a prototype hardware model of the testbed. This paper will present our idea of the 3D micro-gravity simulator and report the results of our initial experiments.

  10. Hierarchical Micro/Nano Structures by Combined Self-Organized Dewetting and Photopatterning of Photoresist Thin Films.

    PubMed

    Sachan, Priyanka; Kulkarni, Manish; Sharma, Ashutosh

    2015-11-17

    Photoresists are the materials of choice for micro/nanopatterning and device fabrication but are rarely used as a self-assembly material. We report for the first time a novel interplay of self-assembly and photolithography for fabrication of hierarchical and ordered micro/nano structures. We create self-organized structures by the intensified dewetting of unstable thin (∼10 nm to 1 μm) photoresist films by annealing them in an optimal solvent and nonsolvent liquid mixture that allows spontaneous dewetting to form micro/nano smooth dome-like structures. The density, size (∼100 nm to millimeters), and curvature/contact angle of the dome/droplet structures are controlled by the film thickness, composition of the dewetting liquid, and time of annealing. Ordered dewetted structures are obtained simply by creating spatial variation of viscosity by ultraviolet exposure or by photopatterning before dewetting. Further, the structures thus fabricated are readily photopatterned again on the finer length scales after dewetting. We illustrate the approach by fabricating several three-dimensional structures of varying complexity with secondary and tertiary features.

  11. A correlative approach for combining microCT, light and transmission electron microscopy in a single 3D scenario

    PubMed Central

    2013-01-01

    Background In biomedical research, a huge variety of different techniques is currently available for the structural examination of small specimens, including conventional light microscopy (LM), transmission electron microscopy (TEM), confocal laser scanning microscopy (CLSM), microscopic X-ray computed tomography (microCT), and many others. Since every imaging method is physically limited by certain parameters, a correlative use of complementary methods often yields a significant broader range of information. Here we demonstrate the advantages of the correlative use of microCT, light microscopy, and transmission electron microscopy for the analysis of small biological samples. Results We used a small juvenile bivalve mollusc (Mytilus galloprovincialis, approximately 0.8 mm length) to demonstrate the workflow of a correlative examination by microCT, LM serial section analysis, and TEM-re-sectioning. Initially these three datasets were analyzed separately, and subsequently they were fused in one 3D scene. This workflow is very straightforward. The specimen was processed as usual for transmission electron microscopy including post-fixation in osmium tetroxide and embedding in epoxy resin. Subsequently it was imaged with microCT. Post-fixation in osmium tetroxide yielded sufficient X-ray contrast for microCT imaging, since the X-ray absorption of epoxy resin is low. Thereafter, the same specimen was serially sectioned for LM investigation. The serial section images were aligned and specific organ systems were reconstructed based on manual segmentation and surface rendering. According to the region of interest (ROI), specific LM sections were detached from the slides, re-mounted on resin blocks and re-sectioned (ultrathin) for TEM. For analysis, image data from the three different modalities was co-registered into a single 3D scene using the software AMIRA®. We were able to register both the LM section series volume and TEM slices neatly to the microCT dataset, with

  12. Predicting Young’s Modulus of Glass/Ceramic Sealant for Solid Oxide Fuel Cell Considering the Combined Effects of Aging, Micro-Voids and Self-Healing

    SciTech Connect

    Liu, Wenning N.; Sun, Xin; Khaleel, Mohammad A.

    2008-12-01

    We study the temperature dependent Young’s modulus for the glass/ceramic seal material used in Solid Oxide Fuel Cells (SOFCs). With longer heat treatment or aging time during operation, further devitrification may reduce the residual glass content in the seal material while boosting the ceramic crystalline content. In the meantime, micro-voids induced by the cooling process from the high operating temperature to room temperature can potentially degrade the mechanical properties of the glass/ceramic sealant. Upon reheating to the SOFC operating temperature, possible self-healing phenomenon may occur in the glass/ceramic sealant which can potentially restore some of its mechanical properties. A phenomenological model is developed to model the temperature dependent Young’s modulus of glass/ceramic seal considering the combined effects of aging, micro-voids, and possible self-healing. An aging-time-dependent crystalline content model is first developed to describe the increase of the crystalline content due to the continuing devitrification under high operating temperature. A continuum damage mechanics (CDM) model is then adapted to model the effects of both cooling induced micro-voids and reheating induced self-healing. This model is applied to model the glass-ceramic G18, a candidate SOFC seal material previously developed at PNNL. Experimentally determined temperature dependent Young’s modulus is used to validate the model predictions

  13. Combination of micro-dialysis and infrared spectroscopy: a multianalyte assay for accurate biofluid analysis and patient monitoring

    NASA Astrophysics Data System (ADS)

    Vahlsing, Thorsten; Delbeck, Sven; Budde, Janpeter; Ihrig, Dieter; Heise, H. Michael

    2016-03-01

    Micro-dialysis can be used for continuously harvesting body fluids, while a multi-component analysis of the dialysates by infrared spectrometry offers splendid opportunities for monitoring substrates and metabolites such as glucose, lactate and others small enough to penetrate the semi-permeable dialysis membranes. However, a drawback of this process are variable recovery rates, which can be observed especially for subcutaneously implanted catheters in human subjects. Isotonic perfusates were investigated with acetate and mannitol as recovery markers for the dialysis of human serum at 37°C to mimic in vivo patient monitoring. The latter non-ionic substance has been suggested for application when other ionic substances such as bicarbonate or pH are also to be determined. Simultaneously for acetate and mannitol, the depletion of the marker substances from the perfusates using different micro-dialysis devices was investigated under various flow-rates. Relationships between relative dialysate marker concentrations and glucose recovery rates were determined based on multivariate calibrations. For quantification, classical least squares with reference spectra for modelling the serum dialysates was used, rendering a basis for reliable blood glucose and lactate measurements.

  14. Improvement of the probiotic effect of micro-organisms by their combination with maltodextrins, fructo-oligosaccharides and polyunsaturated fatty acids.

    PubMed

    Bomba, A; Nemcová, R; Gancarcíková, S; Herich, R; Guba, P; Mudronová, D

    2002-09-01

    Probiotics could represent an effective alternative to the use of synthetic substances in nutrition and medicine. The data concerning the efficacy of probiotics are often contradictory. This paper focuses on the enhancement of the efficacy of probiotics by their combination with synergistically acting components of natural origin. Maltodextrins can be obtained by enzymatic hydrolysis of starch and are suitable for consumption. Administration of Lactobacillus paracasei together with maltodextrin decreased the number of Escherichia coli colonising the jejunal mucosa of gnotobiotic piglets by 1 logarithm compared to the control group. Fructo-oligosaccharides (FOS) are naturally occurring oligosaccharides, mainly of plant origin. L. paracasei administered in combination with FOS significantly increased counts of Lactobacillus spp., Bifidobacterium spp., total anaerobes and total aerobes compared to the control group as well as the L. paracasei group. It also significantly decreased Clostridium and Enterobacterium counts in the faeces of the weanling piglets compared with the control group. Dietary lipids influence the gastrointestinal microbiota and specifically the population of lactic acid bacteria. In gnotobiotic piglets the oral administration of an oil containing polyunsaturated fatty acids (PUFA) significantly increased the number of L. paracasei adhering to jejunal mucosa compared to the control group. Our results showed that maltodextrin KMS X-70 and PUFA can be used to enhance the effect of probiotic micro-organisms in the small intestine, and similarly FOS enhance the effect of probiotic micro-organisms in the large intestine.

  15. Combined RT-qPCR of mRNA and microRNA Targets within One Fluidigm Integrated Fluidic Circuit.

    PubMed

    Baldwin, Don A; Horan, Annamarie D; Hesketh, Patrick J; Mehta, Samir

    2016-07-01

    The ability to profile expression levels of a large number of mRNAs and microRNAs (miRNAs) within the same sample, using a single assay method, would facilitate investigations of miRNA effects on mRNA abundance and streamline biomarker screening across multiple RNA classes. A protocol is described for reverse transcription of long RNA and miRNA targets, followed by preassay amplification of the pooled cDNAs and quantitative PCR (qPCR) detection for a mixed panel of candidate RNA biomarkers. The method provides flexibility for designing custom target panels, is robust over a range of input RNA amounts, and demonstrated a high assay success rate.

  16. Combined RT-qPCR of mRNA and microRNA Targets within One Fluidigm Integrated Fluidic Circuit

    PubMed Central

    Baldwin, Don A.; Horan, Annamarie D.; Hesketh, Patrick J.

    2016-01-01

    The ability to profile expression levels of a large number of mRNAs and microRNAs (miRNAs) within the same sample, using a single assay method, would facilitate investigations of miRNA effects on mRNA abundance and streamline biomarker screening across multiple RNA classes. A protocol is described for reverse transcription of long RNA and miRNA targets, followed by preassay amplification of the pooled cDNAs and quantitative PCR (qPCR) detection for a mixed panel of candidate RNA biomarkers. The method provides flexibility for designing custom target panels, is robust over a range of input RNA amounts, and demonstrated a high assay success rate. PMID:26977138

  17. A Combined Micro-CT Imaging/Microfluidic Approach for Understating Methane Recovery in Coal Seam Gas Reservoirs

    NASA Astrophysics Data System (ADS)

    Mostaghimi, P.; Armstrong, R. T.; Gerami, A.; Lamei Ramandi, H.; Ebrahimi Warkiani, M.

    2015-12-01

    Coal seam methane is a form of natural gas stored in coal beds and is one of the most important unconventional resources of energy. The flow and transport in coal beds occur in a well-developed system of natural fractures that are also known as cleats. We use micro-Computed Tomography (CT) imaging at both dry and wet conditions to resolve the cleats below the resolution of the image. Scanning Electron Microscopy (SEM) is used for calibration of micro-CT data. Using soft lithography technique, the cleat system is duplicated on a silicon mould. We fabricate a microfluidic chip using Polydimethylsiloxane (PDMS) to study both imbibition and drainage in generated coal structures for understating gas and water transport in coal seam reservoirs. First, we use simple patterns observed on coal images to analyse the effects of wettability, cleat size and distribution on flow behaviour. Then, we study transport in a coal by injecting both distilled water and decane with a rate of 1 microliter/ min into the fabricated cleat structure (Figure 1), initially saturated with air. We repeat the experiment for different contact angles by plasma treating the microfluidic chip, and results show significant effects of wettability on the displacement efficiency. The breakthrough time in the imbibition setup is significantly longer than in the drainage. Using rapid video capturing, and high resolution microscopy, we measure the saturation of displacing fluid with respect to time. By measuring gas and liquid recovery in the outlet at different saturation, we predict relative permeability of coal. This work has important applications for optimising gas recovery and our results can serve as a benchmark in the verification of multiphase numerical models used in coal seam gas industry.

  18. Combining micro computed tomography and three-dimensional registration to evaluate local strains in shape memory scaffolds.

    PubMed

    Bormann, Therese; Schulz, Georg; Deyhle, Hans; Beckmann, Felix; de Wild, Michael; Küffer, Jürg; Münch, Christoph; Hoffmann, Waldemar; Müller, Bert

    2014-02-01

    Appropriate mechanical stimulation of bony tissue enhances osseointegration of load-bearing implants. Uniaxial compression of porous implants locally results in tensile and compressive strains. Their experimental determination is the objective of this study. Selective laser melting is applied to produce open-porous NiTi scaffolds of cubic units. To measure displacement and strain fields within the compressed scaffold, the authors took advantage of synchrotron radiation-based micro computed tomography during temperature increase and non-rigid three-dimensional data registration. Uniaxial scaffold compression of 6% led to local compressive and tensile strains of up to 15%. The experiments validate modeling by means of the finite element method. Increasing the temperature during the tomography experiment from 15 to 37°C at a rate of 4 K h(-1), one can locally identify the phase transition from martensite to austenite. It starts at ≈ 24°C on the scaffolds bottom, proceeds up towards the top and terminates at ≈ 34°C on the periphery of the scaffold. The results allow not only design optimization of the scaffold architecture, but also estimation of maximal displacements before cracks are initiated and of optimized mechanical stimuli around porous metallic load-bearing implants within the physiological temperature range. PMID:24257506

  19. An electrochemical biosensor for sensitive detection of microRNA-155: combining target recycling with cascade catalysis for signal amplification.

    PubMed

    Wu, Xiaoyan; Chai, Yaqin; Zhang, Pu; Yuan, Ruo

    2015-01-14

    In this work, a new electrochemical biosensor based on catalyzed hairpin assembly target recycling and cascade electrocatalysis (cytochrome c (Cyt c) and alcohol oxidase (AOx)) for signal amplification was constructed for highly sensitive detection of microRNA (miRNA). It is worth pointing out that target recycling was achieved only based on strand displacement process without the help of nuclease. Moreover, porous TiO2 nanosphere was synthesized, which could offer more surface area for Pt nanoparticles (PtNPs) enwrapping and enhance the amount of immobilized DNA strand 1 (S1) and Cyt c accordingly. With the mimicking sandwich-type reaction, the cascade catalysis amplification strategy was carried out by AOx catalyzing ethanol to acetaldehyde with the concomitant formation of high concentration of H2O2, which was further electrocatalyzed by PtNPs and Cyt c. This newly designed biosensor provided a sensitive detection of miRNA-155 from 0.8 fM to 1 nM with a relatively low detection limit of 0.35 fM.

  20. Combining a micro/nano-hierarchical scaffold with cell-printing of myoblasts induces cell alignment and differentiation favorable to skeletal muscle tissue regeneration.

    PubMed

    Yeo, Miji; Lee, Hyeongjin; Kim, Geun Hyung

    2016-01-01

    Biomedical scaffolds must be used in tissue engineering to provide physical stability and topological/biochemical properties that directly affect tissue regeneration. In this study, a new cell-laden scaffold was developed that supplies micro/nano-topological cues and promotes efficient release of cells. The hierarchical structure consisted of poly(ε-caprolactone) macrosized struts for sustaining a three-dimensional structural shape, aligned nanofibers obtained with optimized electrospinning, and cell-printed myoblasts. Importantly, the printed myoblasts were fully safe and were efficiently released from the cell-laden struts to neighboring nanofiber networks. The incorporation of micro/nanofibers in the hierarchical scaffold significantly affected myoblast proliferation, alignment, and even facilitated the formation of myotubes. We observed that myosin heavy chain expression and the expression levels of various myogenic genes (MyoD, myogenin, and troponin T) were significantly affected by the fiber alignment achieved in our hierarchical cell-laden structure. We believe that the combination of cell-printing and a hierarchical scaffold that encourages fiber alignment is a highly promising technique for skeletal muscle tissue engineering. PMID:27634918

  1. Three dimensional visualization of engineered bone and soft tissue by combined x-ray micro-diffraction and phase contrast tomography

    NASA Astrophysics Data System (ADS)

    Cedola, Alessia; Campi, Gaetano; Pelliccia, Daniele; Bukreeva, Inna; Fratini, Michela; Burghammer, Manfred; Rigon, Luigi; Arfelli, Fulvia; Chen, Rong Chang; Dreossi, Diego; Sodini, Nicola; Mohammadi, Sara; Tromba, Giuliana; Cancedda, Ranieri; Mastrogiacomo, Maddalena

    2014-01-01

    Computed x-ray phase contrast micro-tomography is the most valuable tool for a three dimensional (3D) and non destructive analysis of the tissue engineered bone morphology. We used a Talbot interferometer installed at SYRMEP beamline of the ELETTRA synchrotron (Trieste, Italy) for a precise 3D reconstruction of both bone and soft connective tissue, regenerated in vivo within a porous scaffold. For the first time the x-ray tomographic reconstructions have been combined with x-ray scanning micro-diffraction measurement on the same sample, in order to give an exhaustive identification of the different tissues participating to the biomineralization process. As a result, we were able to investigate in detail the different densities in the tissues, distinguishing the 3D organization of the amorphous calcium phosphate from the collagen matrix. Our experimental approach allows for a deeper understanding of the role of collagen matrix in the organic-mineral transition, which is a crucial issue for the development of new bio-inspired composites.

  2. Design and validation of a novel bioreactor principle to combine online micro-computed tomography monitoring and mechanical loading in bone tissue engineering.

    PubMed

    Hagenmüller, Henri; Hitz, Marco; Merkle, Hans P; Meinel, Lorenz; Müller, Ralph

    2010-01-01

    Mechanical loading plays an important role in bone remodeling in vivo and, therefore, has been suggested as a key parameter in stem cell-based engineering of bone-like tissue in vitro. However, the optimization of loading protocols during stem cell differentiation and subsequent bone-like tissue formation is challenged by multiple input factors, which are difficult to control and validate. These include the variable cellular performance of cells harvested from different patients, nonstandardized culture media components, the choice of the biomaterial forming the scaffold, and its morphology, impacting a broader validity of mechanical stimulation regimens. To standardize the cell culture of bone-like tissue constructs, we suggest the involvement of time-lapsed feedback loops. For this purpose we present a prototype bioreactor that combines online, nondestructive monitoring using micro-computed tomography and direct mechanical loading of three-dimensional tissue engineering constructs. Validation of this system showed displacement steps down to 1 microm and cyclic sinusoidal loadings of up to 10 Hz. Load detection resolution was 0.01 N, and micro-computed tomography data were of high quality. For the first time, the developed bioreactor links time-lapsed, nondestructive, and dynamic imaging with mechanical stimulation, designed for cell culture under sterile conditions. This system is believed to substantially improve today's experimental options to study and optimize osteogenic stem cell culture and differentiation at the interface with mechanical stimulation.

  3. Design and validation of a novel bioreactor principle to combine online micro-computed tomography monitoring and mechanical loading in bone tissue engineering

    NASA Astrophysics Data System (ADS)

    Hagenmüller, Henri; Hitz, Marco; Merkle, Hans P.; Meinel, Lorenz; Müller, Ralph

    2010-01-01

    Mechanical loading plays an important role in bone remodeling in vivo and, therefore, has been suggested as a key parameter in stem cell-based engineering of bone-like tissue in vitro. However, the optimization of loading protocols during stem cell differentiation and subsequent bone-like tissue formation is challenged by multiple input factors, which are difficult to control and validate. These include the variable cellular performance of cells harvested from different patients, nonstandardized culture media components, the choice of the biomaterial forming the scaffold, and its morphology, impacting a broader validity of mechanical stimulation regimens. To standardize the cell culture of bone-like tissue constructs, we suggest the involvement of time-lapsed feedback loops. For this purpose we present a prototype bioreactor that combines online, nondestructive monitoring using micro-computed tomography and direct mechanical loading of three-dimensional tissue engineering constructs. Validation of this system showed displacement steps down to 1 μm and cyclic sinusoidal loadings of up to 10 Hz. Load detection resolution was 0.01 N, and micro-computed tomography data were of high quality. For the first time, the developed bioreactor links time-lapsed, nondestructive, and dynamic imaging with mechanical stimulation, designed for cell culture under sterile conditions. This system is believed to substantially improve today's experimental options to study and optimize osteogenic stem cell culture and differentiation at the interface with mechanical stimulation.

  4. Combining a micro/nano-hierarchical scaffold with cell-printing of myoblasts induces cell alignment and differentiation favorable to skeletal muscle tissue regeneration.

    PubMed

    Yeo, Miji; Lee, Hyeongjin; Kim, Geun Hyung

    2016-09-16

    Biomedical scaffolds must be used in tissue engineering to provide physical stability and topological/biochemical properties that directly affect tissue regeneration. In this study, a new cell-laden scaffold was developed that supplies micro/nano-topological cues and promotes efficient release of cells. The hierarchical structure consisted of poly(ε-caprolactone) macrosized struts for sustaining a three-dimensional structural shape, aligned nanofibers obtained with optimized electrospinning, and cell-printed myoblasts. Importantly, the printed myoblasts were fully safe and were efficiently released from the cell-laden struts to neighboring nanofiber networks. The incorporation of micro/nanofibers in the hierarchical scaffold significantly affected myoblast proliferation, alignment, and even facilitated the formation of myotubes. We observed that myosin heavy chain expression and the expression levels of various myogenic genes (MyoD, myogenin, and troponin T) were significantly affected by the fiber alignment achieved in our hierarchical cell-laden structure. We believe that the combination of cell-printing and a hierarchical scaffold that encourages fiber alignment is a highly promising technique for skeletal muscle tissue engineering.

  5. Small RNA in situ hybridization in Caenorhabditis elegans, combined with RNA-seq, identifies germline-enriched microRNAs.

    PubMed

    McEwen, Tamara J; Yao, Qiuming; Yun, Sijung; Lee, Chin-Yung; Bennett, Karen L

    2016-10-15

    Over four hundred different microRNAs (miRNAs) have been identified in the genome of the model organism the nematode Caenorhabditis elegans. As the germline is dedicated to the preservation of each species, and almost half of all the cells in an adult nematode are germline, it is likely that regulatory miRNAs are important for germline development and maintenance. In C. elegans the miR35 family has strong maternal effects, contributing to normal embryogenesis and to adult fecundity. To determine whether any particular miRNAs are greatly enriched in the C. elegans germline we used RNA-seq to compare the miRNA populations in several germline-defective strains of adult C. elegans worms, including glp-4(germline proliferation-4), glh-1(germline helicase-1) and dcr-1(dicer-1). Statistical analyses of RNA-seq comparisons identified 13 miRNAs that are germline-enriched, including seven members of the well-studied miR35 family that were reduced as much as 1000-fold in TaqMan qRT PCR miRNA assays. Along with the miR35s, six others: miR-56 (a member of the miR51 family),-70, -244, -260 , -788 and -4813, none of which previously considered as such, were also identified by RNA-seq as germline-enriched candidates. We went on to develop a successful miRNA in situ hybridization protocol for C. elegans, revealing miR35s specifically concentrate during oogenesis in the pachytene region of the gonad, and persist throughout early embryogenesis, while in adult animals neither let-7 nor miR-228 has a germline-bias.

  6. Gadolinium-functionalized nanographene oxide for combined drug and microRNA delivery and magnetic resonance imaging.

    PubMed

    Yang, Hung-Wei; Huang, Chiung-Yin; Lin, Chih-Wen; Liu, Hao-Li; Huang, Chia-Wen; Liao, Shih-Sheng; Chen, Pin-Yuan; Lu, Yu-Jen; Wei, Kuo-Chen; Ma, Chen-Chi M

    2014-08-01

    The delivery of anti-cancer therapeutics to tumors at clinically effective concentrations, while avoiding nonspecific toxicity, remains a major challenge for cancer treatment. Here we present nanoparticles of poly(amidoamine) dendrimer-grafted gadolinium-functionalized nanographene oxide (Gd-NGO) as effective carriers to deliver both chemotherapeutic drugs and highly specific gene-targeting agents such as microRNAs (miRNAs) to cancer cells. The positively charged surface of Gd-NGO was capable of simultaneous adsorption of the anti-cancer drug epirubicin (EPI) and interaction with negatively charged Let-7g miRNA. Using human glioblastoma (U87) cells as a model, we found that this conjugate of Let-7g and EPI (Gd-NGO/Let-7g/EPI) not only exhibited considerably higher transfection efficiency, but also induced better inhibition of cancer cell growth than Gd-NGO/Let-7g or Gd-NGO/EPI. The concentration of Gd-NGO/Let-7g/EPI required for 50% inhibition of cellular growth (IC50) was significantly reduced (to the equivalent of 1.3 μg/mL EPI) compared to Gd-NGO/EPI (3.4 μg/mL EPI). In addition, Gd-NGO/Let-7g/EPI could be used as a contrast agent for magnetic resonance imaging to identify the location and extent of blood-brain barrier opening and quantitate drug delivery to tumor tissues. These results suggest that Gd-NGO/Let-7g/EPI may be a promising non-viral vector for chemogene therapy and molecular imaging diagnosis in future clinical applications.

  7. High-throughput deep screening and identification of four peripheral leucocyte microRNAs as novel potential combination biomarkers for preeclampsia

    PubMed Central

    Wang, Yonghong; Yang, Xukui; Yang, Yuanyuan; Wang, Wenjun; Zhao, Meiling; Liu, Huiqiang; Li, Dongyan; Hao, Min

    2016-01-01

    Objective: To identify the specific microRNA (miRNA) biomarkers of preeclampsia (PE), the miRNA profiles analysis were performed. Study Design: The blood samples were obtained from five PE patients and five normal healthy pregnant women. The small RNA profiles were analyzed to identify miRNA expression levels and find out miRNAs that may associate with PE. The quantitative reverse transcriptase–PCR (qRT-PCR) assay was used to validate differentially expressed peripheral leucocyte miRNAs in a new cohort. Result: The data analysis showed that 10 peripheral leucocyte miRNAs were significantly differently expressed in severe PE patients. Four differently expressed miRNAs were successfully validated using qRT-PCR method. Conclusion: We successfully constructed a model with high accuracy to predict PE. A combination of four peripheral leucocyte miRNAs has great potential to serve as diagnostic biomarkers of PE. PMID:26675000

  8. Elemental and spectroscopic characterization of plasters from Fatih Mosque-Istanbul (Turkey) by combined micro-Raman, FTIR and EDXRF techniques.

    PubMed

    Akyuz, Tanil; Akyuz, Sevim; Gulec, Ahmet

    2015-10-01

    The characterization of the plasters and coloring agents of the wall paintings of Fatih Mosque have been performed using combined micro-Raman, FTIR and EDXRF techniques. The investigations show that the plaster used on the walls has mixed gypsum-lime binders. Cinnabar {HgS}, lead red {Pb3O4} and hematite {α-Fe2O3} were identified in the red surfaces. Blue color is attributed to ultramarine blue {Na8-10Al6Si6O24S2-4}. Green color is assigned to mixtures of green earth, copper phthalocyanine {Cu(C32Cl16N8)} and brochantite {CuSO4·3Cu(OH)2}. Strontium yellow {SrCrO4} and zinc white {ZnO} were also used to ensure the color tone. The results provide a basis for future restoration of wall paints. PMID:25989612

  9. Combined use of direct analysis in real-time/Orbitrap mass spectrometry and micro-Raman spectroscopy for the comprehensive characterization of real explosive samples.

    PubMed

    Bridoux, Maxime C; Schwarzenberg, Adrián; Schramm, Sébastien; Cole, Richard B

    2016-08-01

    Direct Analysis in Real Time (DART™) high-resolution Orbitrap™ mass spectrometry (HRMS) in combination with Raman microscopy was used for the detailed molecular level characterization of explosives including not only the charge but also the complex matrix of binders, plasticizers, polymers, and other possible organic additives. A total of 15 defused military weapons including grenades, mines, rockets, submunitions, and mortars were examined. Swabs and wipes were used to collect trace (residual) amounts of explosives and their organic constituents from the defused military weapons and micrometer-size explosive particles were transferred using a vacuum suction-impact collection device (vacuum impactor) from wipe and swap samples to an impaction plate made of carbon. The particles deposited on the carbon plate were then characterized using micro-Raman spectroscopy followed by DART-HRMS providing fingerprint signatures of orthogonal nature. The optical microscope of the micro-Raman spectrometer was first used to localize and characterize the explosive charge on the impaction plate which was then targeted for identification by DART-HRMS analysis in both the negative and positive modes. Raman spectra of the explosives TNT, RDX and PETN were acquired from micrometer size particles and characterized by the presence of their characteristic Raman bands obtained directly at the surface of the impaction plate nondestructively without further sample preparation. Negative mode DART-HRMS confirmed the types of charges contained in the weapons (mainly TNT, RDX, HMX, and PETN; either as individual components or as mixtures). These energetic compounds were mainly detected as deprotonated species [M-H](-), or as adduct [M + (35)Cl](-), [M + (37)Cl](-), or [M + NO3](-) anions. Chloride adducts were promoted in the heated DART reagent gas by adding chloroform vapors to the helium stream using an "in-house" delivery method. When the polarity was switched to positive mode

  10. Combined use of direct analysis in real-time/Orbitrap mass spectrometry and micro-Raman spectroscopy for the comprehensive characterization of real explosive samples.

    PubMed

    Bridoux, Maxime C; Schwarzenberg, Adrián; Schramm, Sébastien; Cole, Richard B

    2016-08-01

    Direct Analysis in Real Time (DART™) high-resolution Orbitrap™ mass spectrometry (HRMS) in combination with Raman microscopy was used for the detailed molecular level characterization of explosives including not only the charge but also the complex matrix of binders, plasticizers, polymers, and other possible organic additives. A total of 15 defused military weapons including grenades, mines, rockets, submunitions, and mortars were examined. Swabs and wipes were used to collect trace (residual) amounts of explosives and their organic constituents from the defused military weapons and micrometer-size explosive particles were transferred using a vacuum suction-impact collection device (vacuum impactor) from wipe and swap samples to an impaction plate made of carbon. The particles deposited on the carbon plate were then characterized using micro-Raman spectroscopy followed by DART-HRMS providing fingerprint signatures of orthogonal nature. The optical microscope of the micro-Raman spectrometer was first used to localize and characterize the explosive charge on the impaction plate which was then targeted for identification by DART-HRMS analysis in both the negative and positive modes. Raman spectra of the explosives TNT, RDX and PETN were acquired from micrometer size particles and characterized by the presence of their characteristic Raman bands obtained directly at the surface of the impaction plate nondestructively without further sample preparation. Negative mode DART-HRMS confirmed the types of charges contained in the weapons (mainly TNT, RDX, HMX, and PETN; either as individual components or as mixtures). These energetic compounds were mainly detected as deprotonated species [M-H](-), or as adduct [M + (35)Cl](-), [M + (37)Cl](-), or [M + NO3](-) anions. Chloride adducts were promoted in the heated DART reagent gas by adding chloroform vapors to the helium stream using an "in-house" delivery method. When the polarity was switched to positive mode

  11. A novel approach combining the Calgary Biofilm Device and Phenotype MicroArray for the characterization of the chemical sensitivity of bacterial biofilms.

    PubMed

    Santopolo, L; Marchi, E; Frediani, L; Decorosi, F; Viti, C; Giovannetti, L

    2012-01-01

    A rapid method for screening the metabolic susceptibility of biofilms to toxic compounds was developed by combining the Calgary Biofilm Device (MBEC device) and Phenotype MicroArray (PM) technology. The method was developed using Pseudomonas alcaliphila 34, a Cr(VI)-hyper-resistant bacterium, as the test organism. P. alcaliphila produced a robust biofilm after incubation for 16 h, reaching the maximum value after incubation for 24 h (9.4 × 10(6) ± 3.3 × 10(6) CFU peg(-1)). In order to detect the metabolic activity of cells in the biofilm, dye E (5×) and menadione sodium bisulphate (100 μM) were selected for redox detection chemistry, because they produced a high colorimetric yield in response to bacterial metabolism (340.4 ± 6.9 Omnilog Arbitrary Units). This combined approach, which avoids the limitations of traditional plate counts, was validated by testing the susceptibility of P. alcaliphila biofilm to 22 toxic compounds. For each compound the concentration level that significantly lowered the metabolic activity of the biofilm was identified. Chemical sensitivity analysis of the planktonic culture was also performed, allowing comparison of the metabolic susceptibility patterns of biofilm and planktonic cultures.

  12. Short-Term Intraocular Pressure Elevations after Combined Phacoemulsification and Implantation of Two Trabecular Micro-Bypass Stents: Prednisolone versus Loteprednol

    PubMed Central

    Wang, Qianqian; Harasymowycz, Paul

    2015-01-01

    Objective. To compare the effects of prednisolone and of loteprednol after combined phacoemulsification and trabecular micro-bypass stent implantation (phaco-iStent). Methods. Patients who underwent phaco-iStent between April 2013 and November 2014 were identified by retrospective chart review. Postoperatively, they received either prednisolone (n = 38) or loteprednol (n = 58). Baseline data was compared. Primary outcomes including intraocular pressure (IOP) and number of glaucoma medications (NGM) were analyzed at preoperative visit, postoperative day 1, weeks 1-2, weeks 3-4, and months 2-3. Results. Both groups had similar preoperative parameters (p > 0.05). The mean IOP spike occurred at postoperative weeks 1-2 with an increase of 2.21 ± 7.30 mmHg in the loteprednol group and 2.54 ± 9.28 mmHg in the prednisolone group. It decreased by weeks 3-4 in both groups and continued to improve at months 2-3. NGM showed significant reduction (p < 0.0001) after the surgery and remained stable in both groups. No significant group effect or time-group interaction in IOP and NGM evolution was detected (p > 0.05). The proportions of patients needing paracentesis were similar between the two groups. Conclusion. Similar early IOP elevations after combined phaco-iStent occurred with both prednisolone and loteprednol. Facilitated glucocorticoid infusion, altered aqueous humor outflow, and local inflammation may be contributing factors. PMID:26266045

  13. Sol-gel concave micro-lens arrays fabricated by combining the replicated PDMS soft mold with UV-cured imprint process

    NASA Astrophysics Data System (ADS)

    Zhang, Xuehua; Que, Wenxiu; Chen, Jing; Hu, Jiaxing; Gao, Tianxi; Liu, Weiguo

    2013-11-01

    Photosensitive TiO2/organically modified silane organic-inorganic hybrid thin films were synthesized by combining a low-temperature sol-gel process with a spin-coating method. Optical transmittance properties and the photochemical activities of the planar hybrid films were characterized by UV-Visible spectroscopy and Fourier transform infrared spectroscopy. Advantages for fabrication of the concave micro-lens arrays (MLAs) based on the photosensitive hybrid films were demonstrated by using the replicated polydimethylsiloxane (PDMS) soft mold as the imprint mold and a UV soft imprint technique. Morphological and surface profile properties of the master, the PDMS soft molds and the as-fabricated sol-gel concave MLAs were observed by scanning electron microscopy and laser confocal scanning microscopy. Contact angles of water on the PDMS soft molds baked at different temperatures were studied. Optical imaging properties of the as-fabricated concave MLAs were confirmed by a self-made optical test system. Results indicate that the as-prepared photo-patternable hybrid materials have great applicability for the fabrication of photonic components, thus providing an effective method to fabricate concave MLAs based on the as-synthesized hybrid films by combining the UV-cured imprint technique with the replicated PDMS soft mold, which has advantages of simplicity, cost-effective and mass production and potential application in industry production.

  14. The Effect of Docetaxel-Loaded Micro-Bubbles Combined with Low-Frequency Ultrasound in H22 Hepatocellular Carcinoma-Bearing Mice.

    PubMed

    Ren, Shu-Ting; Shen, Shu; He, Xin-Ying; Liao, Yi-Ran; Sun, Peng-Fei; Wang, Bing; Zhao, Wen-Bao; Han, Shui-Ping; Wang, Yi-Li; Tian, Tian

    2016-02-01

    A novel lipid micro-bubble (MB) loaded with docetaxel (DOC-MB) was investigated in a previous study. However, its anti-tumor effects and mechanism of action in combination with low-frequency ultrasound (LFUS) in vivo are still unclear. DOC-MBs containing 5.0 mg of DOC were prepared by lyophilization with modification via ultrasonic emulsification. Then, the effects of DOC-MBs combined with LFUS on tumor growth, proliferating cell nuclear antigen (PCNA) expression and cell apoptosis, as well as local DOC delivery, were investigated in H22 hepatocellular carcinoma (HCC)-bearing mice. Compared with the previously prepared DOC-MBs (1.6 mg of DOC loaded), the encapsulation efficiency (81.2% ± 3.89%) and concentration ([7.94 ± 0.04] × 10(9) bubbles/mL) of the DOC-MBs containing 5.0 mg of DOC were higher, but the bubble size (1.368 ± 0.004 μm) was smaller. After treatment with the DOC-MBs and LFUS, the H22 HCC growth inhibition rate was significantly increased, PCNA expression in tumor tissue was significantly inhibited and local release of DOC was induced. In conclusion, new DOC-MBs containing 5.0 mg of DOC were successfully prepared with a high encapsulation efficiency and superior bubble size and concentration, and their combination with LFUS significantly enhanced the anti-tumor effect of DOC in H22 HCC-bearing mice by inhibiting tumor cell proliferation and increasing local drug delivery.

  15. Wild 2 grains characterized combining MIR/FIR/Raman micro-spectroscopy and FE-SEM/EDS analyses

    NASA Astrophysics Data System (ADS)

    Ferrari, M.; Rotundi, A.; Rietmeijer, F. J. M.; Della Corte, V.; Baratta, G. A.; Brunetto, R.; Dartois, E.; Djouadi, Z.; Merouane, S.; Borg, J.; Brucato, J. R.; Le Sergeant d'Hendecourt, L.; Mennella, V.; Palumbo, M. E.; Palumbo, P.

    We present the results of the analyses \\cite{Rotundi14} of two bulk terminal particles (TPs), C2112,7,171,0,0 (TP2) and C2112,9,171,0,0 (TP3), derived from the Jupiter-Family comet 81P/Wild 2 returned by the NASA Stardust mission \\cite{Brownlee06}. Each particle, embedded in a slab of silica aerogel, was pressed in a diamond cell. Aerogel is usually cause of problems when characterizing the minerals and organic materials present in the embedded particles. We overcame this common issue by means of the combination of FE-SEM/EDS, IR and Raman mu -spectroscopy, three non-destructive analytical techniques, which provided bulk mineralogical and organic information on TP2 and TP3. This approach proved to be a practical solution for preliminary characterization, i.e. scanning particles for chemical and mineralogical heterogeneity. Using this type of bulk characterization prior to more detailed studies, could be taken into account as a standard procedure to be followed for selecting Stardust particles-of-interest. TP2 and TP3 are dominated by Ca-free and low-Ca, Mg-rich, Mg,Fe-olivine. The presence of melilite in both particles is supported by IR mu -spectroscopy and corroborated by FE-SEM/EDS analyses, but is not confirmed by Raman mu -spectroscopy possibly because the amount of this mineral is too small to be detected. TP2 and TP3 show similar silicate mineral compositions, but Ni-free, low-Ni, sub-sulfur (Fe,Ni)S grains are present only in TP2. TP2 contains indigenous amorphous carbon hot spots, while no indigenous carbon was identified in TP3. These non-chondritic particles probably originated in a differentiated body. The presence of high temperature melilite group minerals (incl. gehlenite) in TP2 and TP3 reinforces the notion that collisionally-ejected refractory debris from differentiated asteroids may be common in Jupiter-Family comets. This raises the question whether similar debris and other clearly asteroidal particles could be present in Halley-type comets

  16. Wild 2 grains characterized combining MIR/FIR/Raman micro-spectroscopy and FE-SEM/EDS analyses

    NASA Astrophysics Data System (ADS)

    Rotundi, Alessandra; Rietmeijer, Frans J. M.; Ferrari, Marco; Della Corte, Vincenzo; Baratta, Giuseppe A.; Brunetto, Rosario; Dartois, Emmanuel; Djouadi, Zahia; Merouane, Sihane; Borg, Janet; Brucato, John R.; Le Sergeant d'Hendecourt, Louis; Mennella, Vito; Palumbo, Maria Elisabetta; Palumbo, Pasquale

    2014-05-01

    We present the analyses results of two bulk Terminal Particles, C2112,7,171,0,0 and C2112,9,171,0,0, derived from the Jupiter-Family comet 81P/Wild 2 returned by the Stardust mission. Each particle embedded in a slab of silica aerogel was pressed in a diamond cell. The aerogel, as expected, caused problems to identify the minerals and organic materials present in these particles. These problems were overcome by means of the combination of FE-SEM/EDS, IR and Raman μ-spectroscopy, three non-destructive analytical techniques, which allowed the mineral and organic information on the two bulk particles. Indeed, this approach proved to be practical for preliminary characterization, i.e. scanning particles for chemical and mineralogical heterogeneity. It can be considered as a procedure to be followed for selecting Stardust particles-of- interest using this type of bulk characterization prior to more detailed studies. TP2 and TP3 are dominated by Ca-free and low-Ca, Mg-rich, Mg,Fe-olivine. The presence of melilite in both particles is supported by IR μ-spectroscopy, but is not confirmed by Raman μ-spectroscopy possibly because the amounts are too small to be detected. TP2 and TP3 show similar silicate mineral compositions but Ni-free and low-Ni, sub-sulfur (Fe,Ni)S grains are present in TP2 only. TP2 contains indigenous amorphous carbon hot spots; no indigenous carbon was identified in TP3. These non-chondritic particles probably originated in a differentiated body. The presence of high temperature melilite group minerals (incl. gehlenite) in TP2 and TP3 reinforces the notion that collisionally-ejected refractory debris from differentiated asteroids may be common in Jupiter-Family comets. It does raise the question if similar debris and other clearly asteroidal dust could be present in Halley-type comets and if so what fractions of the dust in these comets are truly non-processed silicates and organic material. The results of this study will be relevant to the ROSETTA

  17. Ultrasensitive electrochemical detection of microRNA-21 combining layered nanostructure of oxidized single-walled carbon nanotubes and nanodiamonds by hybridization chain reaction.

    PubMed

    Liu, Lingzhi; Song, Chao; Zhang, Zhang; Yang, Juan; Zhou, Lili; Zhang, Xing; Xie, Guoming

    2015-08-15

    Measurement of microRNA (miRNA) levels in body fluids is a crucial tool for the early diagnosis and prognosis of cancers. In this study, we developed an electrochemical assay to detect miRNA-21 by fabricating the electrode with layer-by-layer assembly of oxidized single-walled carbon nanotubes and nanodiamonds. Tetrahedron-structured probes with free-standing probe on the top served as receptors to hybridize with target miRNA directly. The probes were immobilized on the deposited gold nanoparticles through a well-established strong Au-S bond. The electrochemical signal was mainly derived from an ultrasensitive pattern by combining hybridization chain reaction with DNA-functionalized AuNPs, which provided DNAzyme to catalyze H2O2 reduction. Differential pulse voltammetry was applied to record the electrochemical signals, which was increased linearly with the target miRNA-21, and the linear detection range was 10 fM to 1.0 nM. The limit of detection reached 1.95 fM (S/N=3), and the proposed biosensor exhibited good reproducibility and stability, as well as high sensitivity. Hence, this biosensor has a promising potential in clinical application.

  18. Illustration of compositional variations over time of Chinese porcelain glazes combining micro-X-ray Fluorescence spectrometry, multivariate data analysis and Seger formulas

    NASA Astrophysics Data System (ADS)

    Van Pevenage, J.; Verhaeven, E.; Vekemans, B.; Lauwers, D.; Herremans, D.; De Clercq, W.; Vincze, L.; Moens, L.; Vandenabeele, P.

    2015-01-01

    In this research, the transparent glaze layers of Chinese porcelain samples were investigated. Depending on the production period, these samples can be divided into two groups: the samples of group A dating from the Kangxi period (1661-1722), and the samples of group B produced under emperor Qianlong (1735-1795). Due to the specific sample preparation method and the small spot size of the X-ray beam, investigation of the transparent glaze layers is enabled. Despite the many existing research papers about glaze investigations of ceramics and/or porcelain ware, this research reveals new insights into the glaze composition and structure of Chinese porcelain samples. In this paper it is demonstrated, using micro-X-ray Fluorescence (μ-XRF) spectrometry, multivariate data analysis and statistical analysis (Hotelling's T-Square test) that the transparent glaze layers of the samples of groups A and B are significantly different (95% confidence level). Calculation of the Seger formulas, enabled classification of the glazes. Combining all the information, the difference in composition of the Chinese porcelain glazes of the Kangxi period and the Qianlong period can be demonstrated.

  19. Simultaneous analysis of eight phenolic environmental estrogens in blood using dispersive micro-solid-phase extraction combined with ultra fast liquid chromatography-tandem mass spectrometry.

    PubMed

    Zhao, Yong-Gang; Chen, Xiao-Hong; Pan, Sheng-Dong; Zhu, Hao; Shen, Hao-Yu; Jin, Mi-Cong

    2013-10-15

    A novel, simple and sensitive method was developed for the simultaneous determination of eight phenolic environmental estrogens in blood by using the dispersive micro-solid-phase extraction (d-µ-SPE) procedure combined with ultra-fast liquid chromatography-tandem quadrupole mass spectrometry (UFLC-MS/MS). The excellent nanomaterials tetraethylenepentamine-functionalized magnetic polymer was used as an adsorbent, and the main factors affecting the extraction efficiency were investigated in detail. All target compounds showed good linearities in the tested range with correlation coefficients (r) higher than 0.999. The mean recoveries were in the range of 85.0-105.0%. The intra-day and inter-day relative standard deviations (RSDs) were lower than 4.9% and 5.2%, respectively. The limits of quantification for the eight phenolic environmental estrogens were between 0.075 and 0.42 µg L(-1). The developed method can be applied to the routine analyses for the determination of the eight phenolic environmental estrogens in blood samples.

  20. Evaluating misoprostol content in pregnant women with hourly oral administration during labor induction by microElution solid phase extraction combined with liquid chromatography tandem mass spectrometry.

    PubMed

    Hung, Cheng-Han; Cheng, Shi-Yann; Chan, Tzu-Min; Lee, Maw-Rong

    2015-09-01

    Misoprostol is a widely used alternative of prostaglandin for labor induction. Based on previous studies, we envision that small and frequent oral dosage of misoprostol is an effective method for labor induction. To monitor the misoprostol content during labor induction, a rapid, sensitive, and selective microElution solid phase extraction (μElution SPE) combined with liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed. Using μElution SPE could minimize the sample consumption and elution volume in order to maximize the sample enrichment and throughput. The misoprostol acid, a metabolite of misoprostol, was gradient separated in a Bidentate C18 column, then quantified by highly-selective reaction monitoring (H-SRM) in a total run time of 6min. The developed method was optimized and validated in human plasma, and showed linear range of 0.01-10ng/mL. The limit of detection (LOD) was 0.001ng/mL. The recovery ranged from 89.0 to 96.0%, and no significant matrix effect or carryover was observed. The precision, accuracy and stability were met with the criteria of U.S. FDA guidance. The developed method was successfully applied to evaluate misoprostol concentration during labor induction in pregnant women. The concentration-time profiles approves that hourly oral administration of misoprostol is a safe and effective method without drug accumulation for labor induction. PMID:26245361

  1. Structure and properties of a duplex coating combining micro-arc oxidation and baking layer on AZ91D Mg alloy

    NASA Astrophysics Data System (ADS)

    Cui, Xue-Jun; Li, Ming-Tian; Yang, Rui-Song; Yu, Zu-Xiao

    2016-02-01

    A duplex coating (called MAOB coating) was fabricated on AZ91D Mg alloy by combining the process of micro-arc oxidation (MAO) with baking coating (B-coating). The structure, composition, corrosion resistance, and tribological behaviour of the coatings were investigated using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), electrochemical and long-term immersion test, and ball-on-disc friction test. The results show that a dense 92 μm thick B-coating was tightly deposited onto the MAO-coated Mg alloy and exhibited a good mechanical interlock along the rough interface. Compared with the MAO-coated sample, the corrosion current density of the MAOB-coated Mg alloy decreased by two or three orders of magnitude and no corrosion phenomenon was observed during a long-term immersion test of about 500 h (severe corrosion pits were found for MAO-treated samples after about 168 h of immersion). The frictional coefficient values of the MAOB coating were similar to those of the MAO coating using dry sliding tests, while the B-coating on the MAO-coated surface significantly improved the wear resistance of the AZ91D Mg alloy. All of these results indicate that a B-coating can be used to further protect Mg alloys from corrosion and wear by providing a thick, dense barrier.

  2. The n-MAO/EPD bio-ceramic composite coating fabricated on ZK60 magnesium alloy using combined micro-arc oxidation with electrophoretic deposition

    NASA Astrophysics Data System (ADS)

    Xiong, Ying; Lu, Chao; Wang, Chao; Song, Renguo

    2014-12-01

    A bio-ceramic composite coating was fabricated on ZK60 magnesium (Mg) alloy using combined micro-arc oxidation (MAO) with electrophoretic deposition (EPD) technique. The MAO coating as the basal layer was produced in alkaline electrolyte with (n-MAO coating) and without (MAO coating) the addition of CeO2 and ZrO2 nano-particles, respectively. A hydroxyapatite (HA) coating as the covering layer was deposited on the n-MAO coating to improve the biological properties of the coating (n-MAO/EPD composite coating). The morphology and phase composition of three treated coatings were investigated by scanning electron microscope (SEM) and X-ray diffraction (XRD). The corrosion resistance of these coatings was evaluated with potentiodynamic polarization tests and immersion tests in simulated body fluid (SBF) at 36.5 ± 0.5 °C. The XRD spectra showed that the CeO2 and ZrO2 peaks can be collected in the n-MAO coating, and HA particles exists in the n-MAO/EPD composite coating. The results of corrosion tests indicated that the n-MAO/EPD composite coating owned increased bioactivity and long-term protective ability compared with the MAO coating and the n-MAO coating. Thus Mg alloy coated with the n-MAO/EPD composite coating should be more suited as biodegradable bone implants.

  3. Evaluating misoprostol content in pregnant women with hourly oral administration during labor induction by microElution solid phase extraction combined with liquid chromatography tandem mass spectrometry.

    PubMed

    Hung, Cheng-Han; Cheng, Shi-Yann; Chan, Tzu-Min; Lee, Maw-Rong

    2015-09-01

    Misoprostol is a widely used alternative of prostaglandin for labor induction. Based on previous studies, we envision that small and frequent oral dosage of misoprostol is an effective method for labor induction. To monitor the misoprostol content during labor induction, a rapid, sensitive, and selective microElution solid phase extraction (μElution SPE) combined with liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed. Using μElution SPE could minimize the sample consumption and elution volume in order to maximize the sample enrichment and throughput. The misoprostol acid, a metabolite of misoprostol, was gradient separated in a Bidentate C18 column, then quantified by highly-selective reaction monitoring (H-SRM) in a total run time of 6min. The developed method was optimized and validated in human plasma, and showed linear range of 0.01-10ng/mL. The limit of detection (LOD) was 0.001ng/mL. The recovery ranged from 89.0 to 96.0%, and no significant matrix effect or carryover was observed. The precision, accuracy and stability were met with the criteria of U.S. FDA guidance. The developed method was successfully applied to evaluate misoprostol concentration during labor induction in pregnant women. The concentration-time profiles approves that hourly oral administration of misoprostol is a safe and effective method without drug accumulation for labor induction.

  4. Combining Heavy Ion Radiation and Artificial MicroRNAs to Target the Homologous Recombination Repair Gene Efficiently Kills Human Tumor Cells

    SciTech Connect

    Zheng Zhiming; Wang Ping; Wang Hongyan; Zhang Xiangming; Wang Minli; Cucinotta, Francis A.; Wang Ya

    2013-02-01

    Purpose: Previously, we demonstrated that heavy ions kill more cells at the same dose than X-rays because DNA-clustered lesions produced by heavy ions affect nonhomologous end-joining (NHEJ) repair but not homologous recombination repair (HRR). We have also shown that our designed artificial microRNAs (amiRs) could efficiently target XRCC4 (an essential factor for NHEJ) or XRCC2 (an essential factor for HRR) and sensitize human tumor cells to X-rays. Based on these data, we were interested in testing the hypothesis that combining heavy ions and amiRs to target HRR but not NHEJ should more efficiently kill human tumor cells. Methods and Materials: Human tumor cell lines (U87MG, a brain tumor cell line, and A549, a lung cancer cell line) and their counterparts, overexpressed with amiR to target XRCC2, XRCC4 or both, were used in this study. Survival sensitivities were examined using a clonogenic assay after these cells were exposed to X-rays or heavy ions. In addition, these cell lines were subcutaneously injected into nude mice to form xenografts and the tumor size was compared after the tumor areas were exposed to X-rays or heavy ions. Results: Although targeting either XRCC4 (NHEJ factor) or XRCC2 (HRR factor) sensitized the human tumor cells to X-rays, in vitro and the xenograft animal model, targeting only XRCC2 but not XRCC4 sensitized the human tumor cells to heavy ions in vitro and in the xenograft animal model. Conclusions: Combining heavy ions with targeting the HRR pathway, but not the NHEJ pathway, could significantly improve the efficiency of tumor cell death.

  5. Identifying and Validating a Combined mRNA and MicroRNA Signature in Response to Imatinib Treatment in a Chronic Myeloid Leukemia Cell Line

    PubMed Central

    Bhutra, Steven; Lenkala, Divya; LaCroix, Bonnie; Ye, Meng; Huang, R. Stephanie

    2014-01-01

    Imatinib, a targeted tyrosine kinase inhibitor, is the gold standard for managing chronic myeloid leukemia (CML). Despite its wide application, imatinib resistance occurs in 20–30% of individuals with CML. Multiple potential biomarkers have been identified to predict imatinib response; however, the majority of them remain externally uncorroborated. In this study, we set out to systematically identify gene/microRNA (miRNA) whose expression changes are related to imatinib response. Through a Gene Expression Omnibus search, we identified two genome-wide expression datasets that contain expression changes in response to imatinib treatment in a CML cell line (K562): one for mRNA and the other for miRNA. Significantly differentially expressed transcripts/miRNAs post imatinib treatment were identified from both datasets. Three additional filtering criteria were applied 1) miRbase/miRanda predictive algorithm; 2) opposite direction of imatinib effect for genes and miRNAs; and 3) literature support. These criteria narrowed our candidate gene-miRNA to a single pair: IL8 and miR-493-5p. Using PCR we confirmed the significant up-regulation and down-regulation of miR-493-5p and IL8 by imatinib treatment, respectively in K562 cells. In addition, IL8 expression was significantly down-regulated in K562 cells 24 hours after miR-493-5p mimic transfection (p = 0.002). Furthermore, we demonstrated significant cellular growth inhibition after IL8 inhibition through either gene silencing or by over-expression of miR-493-5p (p = 0.0005 and p = 0.001 respectively). The IL8 inhibition also further sensitized K562 cells to imatinib cytotoxicity (p<0.0001). Our study combined expression changes in transcriptome and miRNA after imatinib exposure to identify a potential gene-miRNA pair that is a critical target in imatinib response. Experimental validation supports the relationships between IL8 and miR-493-5p and between this gene-miRNA pair and imatinib sensitivity in a CML cell

  6. Useful method to monitor the physiological effects of alcohol ingestion by combination of micro-integrated laser Doppler blood flow meter and arm-raising test.

    PubMed

    Iwasaki, Wataru; Nogami, Hirofumi; Ito, Hiroki; Gotanda, Takeshi; Peng, Yao; Takeuchi, Satoshi; Furue, Masutaka; Higurashi, Eiji; Sawada, Renshi

    2012-10-01

    Alcohol has a variety of effects on the human body, affecting both the sympathetic and parasympathetic nervous system. We examined the peripheral blood flow of alcohol drinkers using a micro-integrated laser Doppler blood flow meter (micro-electromechanical system blood flow sensor). An increased heart rate and blood flow was recorded at the earlobe after alcohol ingestion, and we observed strong correlation between blood flow, heart rate, and breath alcohol content in light drinkers; but not heavy drinkers. We also found that the amplitude of pulse waves measured at the fingertip during an arm-raising test significantly decreased on alcohol consumption, regardless of the individual's alcohol tolerance. Our micro-electromechanical system blood flow sensor successfully detected various physiological changes in peripheral blood circulation induced by alcohol consumption.

  7. Nano/micro hybrid scaffold of PCL or P3HB nanofibers combined with silk fibroin for tendon and ligament tissue engineering.

    PubMed

    Naghashzargar, Elham; Farè, Silvia; Catto, Valentina; Bertoldi, Serena; Semnani, Dariush; Karbasi, Saeed; Tanzi, Maria Cristina

    2015-07-04

    A novel biodegradable nano/micro hybrid structure was obtained by electrospinning P3HB or PCL nanofibers onto a twisted silk fibroin (SF) structure, with the aim of fabricating a suitable scaffold for tendon and ligament tissue engineering. The electrospinning (ES) processing parameters for P3HB and PCL were optimized on 2D samples, and applied to produce two different nano/micro hybrid constructs (SF/ES-PCL and SF/ES-P3HB).Morphological, chemico-physical and mechanical properties of the novel hybrid scaffolds were evaluated by SEM, ATR FT-IR, DSC, tensile and thermodynamic mechanical tests. The results demonstrated that the nanofibers were tightly wrapped around the silk filaments, and the crystallinity of the SF twisted yarns was not influenced by the presence of the electrospun polymers. The slightly higher mechanical properties of the hybrid constructs confirmed an increase of internal forces due to the interaction between nano and micro components. Cell culture tests with L929 fibroblasts, in the presence of the sample eluates or in direct contact with the hybrid structures, showed no cytotoxic effects and a good level of cytocompatibility of the nano/micro hybrid structures in term of cell viability, particularly at day 1. Cell viability onto the nano/micro hybrid structures decreased from the first to the third day of culture when compared with the control culture plastic, but appeared to be higher when compared with the uncoated SF yarns. Although additional in vitro and in vivo tests are needed, the original fabrication method here described appears promising for scaffolds suitable for tendon and ligament tissue engineering.

  8. Surface Characterization and Osteoconductivity Evaluation of Micro/Nano Surface Formed on Titanium Using Anodic Oxidation Combined with H2O2 Etching and Hydrothermal Treatment.

    PubMed

    Park, Eun-Jin; Song, Yo-Han; Hwang, Moon-Jin; Song, Ho-Jun; Park, Yeong-Joon

    2015-08-01

    In this study, surface characteristics and osteoconductivity were investigated for the micro/nanostructured oxide layers fabricated on titanium using anodic oxidation (ANO), chemical etching (Et), and hydrothermal treatment (HT). Commercially pure titanium (CP-Ti) disks were anodic-oxidized using DC-type power supply in 1 M phosphoric acid electrolyte (P-ANO group). These specimens were further chemically etched using 30% H2O2 solution at 60 °C for 10 min (P-ANO-Et group). The P-ANO-Et-HT group was fabricated by hydrothermally treating the P-ANO-Et specimens in phosphorus-containing alkaline solution at 190 °C for 8 hrs. The P-ANO group showed a porous surface that was evenly covered with micro- and sub-micro pores. The size of these pores was decreased in the P-ANO-Et group. The P-ANO-Et-HT group showed a porous surface that was covered with nano-sized crystallites. Anatase TiO2 structure was observed in P-ANO-Et-HT group. The results of XPS demonstrated that the P-ANO-Et-HT group had a well-crystallized TiC2 structure, while the P-ANO and P-ANO-Et groups had an amorphous and phosphate-containing structure. Hydrophilicity of the P-ANO-Et-HT group was the highest. After MG63 osteoblast-like cells were cultured on the specimens for 3 hrs, SEM images of the cells cultured on P-ANO-Et-HT group specimens showed low initial adhesion. However, the osteoconductivity of these specimens increased more rapidly compared to that of the micro-structured surfaces. These results could be applied to fabricate titanium implants with an optimum micro/nano-surface for enhancing their osteoconductivity.

  9. Search for Fluid Inclusions in a Carbonaceous Chondrite Using a New X-Ray Micro-Tomography Technique Combined with FIB Sampling

    NASA Technical Reports Server (NTRS)

    Tsuchiyama, A.; Miyake, A.; Zolensky, M. E.; Uesugi, K.; Nakano, T.; Takeuchi, A.; Suzuki, Y.; Yoshida, K.

    2014-01-01

    Early solar system aqueous fluids are preserved in some H chondrites as aqueous fluid inclusions in halite (e.g., [1]). Although potential fluid inclusions are also expected in carbonaceous chondrites [2], they have not been surely confirmed. In order to search for these fluid inclusions, we have developped a new X-ray micro-tomography technique combined with FIB sampling and applied this techniqu to a carbanaceous chondrite. Experimental: A polished thin section of Sutter's Mill meteorite (CM) was observed with an optical microscope and FE-SEM (JEOL 7001F) for chosing mineral grains of carbonates (mainly calcite) and sulfides (FeS and ZnS) 20-50 microns in typical size, which may have aqueous fluid inclusions. Then, a "house" similar to a cube with a roof (20-30 microns in size) is sampled from the mineral grain by using FIB (FEI Quanta 200 3DS). Then, the house was atached to a thin W-needle by FIB and imaged by a SR-based imaging microtomography system with a Fresnel zone plate at beamline BL47XU, SPring-8, Japan. One sample was imaged at two X-ray energies, 7 and 8 keV, to identify mineral phases (dual-enegy microtomography: [3]). The size of voxel (pixel in 3D) was 50-80 nm, which gave the effective spatial resolution of approx. 200 nm. A terrestrial quartz sample with an aqueous fluid inclusion with a bubble was also examined as a test sample by the same method. Results and discussion: A fluid inclusion of 5-8 microns in quartz was clearly identified in a CT image. A bubble of approx. 4 microns was also identified as refraction contrast although the X-ray absorption difference between fluid and bubble is small. Volumes of the fluid and bubble were obtained from the 3D CT images. Fourteen grains of calcite, two grains of iron sulfide and one grain of (Zn,Fe)S were examined. Ten calcite, one iron sulfide and one (Zn,Fe)S grains have inclusions >1 micron in size (the maximum: approx. 5 microns). The shapes are spherical or irregular. Tiny inclusions (<1 micron

  10. Self-aliquoting micro-grooves in combination with laser ablation-ICP-mass spectrometry for the analysis of challenging liquids: quantification of lead in whole blood.

    PubMed

    Nischkauer, Winfried; Vanhaecke, Frank; Limbeck, Andreas

    2016-08-01

    We present a technique for the fast screening of the lead concentration in whole blood samples using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). The whole blood sample is deposited on a polymeric surface and wiped across a set of micro-grooves previously engraved into the surface. The engraving of the micro-grooves was accomplished with the same laser system used for LA-ICP-MS analysis. In each groove, a part of the liquid blood is trapped, and thus, the sample is divided into sub-aliquots. These aliquots dry quasi instantly and are then investigated by means of LA-ICP-MS. For quantification, external calibration against aqueous standard solutions was relied on, with iron as an internal standard to account for varying volumes of the sample aliquots. The (208)Pb/(57)Fe nuclide ratio used for quantification was obtained via a data treatment protocol so far only used in the context of isotope ratio determination involving transient signals. The method presented here was shown to provide reliable results for Recipe ClinChek® Whole Blood Control levels I-III (nos. 8840-8842), with a repeatability of typically 3 % relative standard deviation (n = 6, for Pb at 442 μg L(-1)). Spiked and non-spiked real whole blood was analysed as well, and the results were compared with those obtained via dilution and sectorfield ICP-MS. A good agreement between both methods was observed. The detection limit (3 s) for lead in whole blood was established to be 10 μg L(-1) for the laser ablation method presented here. Graphical Abstract Micro-grooves are filled with whole blood, dried, and analyzed by laser ablation ICP-mass spectrometry. Notice that the laser moves in perpendicular direction with regard to the micro-grooves. PMID:27363841

  11. Self-aliquoting micro-grooves in combination with laser ablation-ICP-mass spectrometry for the analysis of challenging liquids: quantification of lead in whole blood.

    PubMed

    Nischkauer, Winfried; Vanhaecke, Frank; Limbeck, Andreas

    2016-08-01

    We present a technique for the fast screening of the lead concentration in whole blood samples using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). The whole blood sample is deposited on a polymeric surface and wiped across a set of micro-grooves previously engraved into the surface. The engraving of the micro-grooves was accomplished with the same laser system used for LA-ICP-MS analysis. In each groove, a part of the liquid blood is trapped, and thus, the sample is divided into sub-aliquots. These aliquots dry quasi instantly and are then investigated by means of LA-ICP-MS. For quantification, external calibration against aqueous standard solutions was relied on, with iron as an internal standard to account for varying volumes of the sample aliquots. The (208)Pb/(57)Fe nuclide ratio used for quantification was obtained via a data treatment protocol so far only used in the context of isotope ratio determination involving transient signals. The method presented here was shown to provide reliable results for Recipe ClinChek® Whole Blood Control levels I-III (nos. 8840-8842), with a repeatability of typically 3 % relative standard deviation (n = 6, for Pb at 442 μg L(-1)). Spiked and non-spiked real whole blood was analysed as well, and the results were compared with those obtained via dilution and sectorfield ICP-MS. A good agreement between both methods was observed. The detection limit (3 s) for lead in whole blood was established to be 10 μg L(-1) for the laser ablation method presented here. Graphical Abstract Micro-grooves are filled with whole blood, dried, and analyzed by laser ablation ICP-mass spectrometry. Notice that the laser moves in perpendicular direction with regard to the micro-grooves.

  12. Reduced dental calcium expression and dental mass in chronic sleep deprived rats: Combined EDS, TOF-SIMS, and micro-CT analysis

    NASA Astrophysics Data System (ADS)

    Kuo, Yi-Jie; Huang, Yung-Kai; Chou, Hsiu-Chu; Pai, Man-Hui; Lee, Ai-Wei; Mai, Fu-Der; Chang, Hung-Ming

    2015-08-01

    Teeth are the hardest tissue in the body. The growth of teeth is closely regulated by circadian rhythmicity. Considering that sleep deprivation (SD) is a severe condition that disrupts normal circadian rhythmicity, this study was conducted to determine whether calcium expression (the major element participating in teeth constitution), and dental mass would be significantly impaired following SD. Adolescent rats subjected to 3 weeks of SD were processed for energy dispersive spectrum (EDS), time-of-flight secondary ion mass spectrometry (TOF-SIMS), and micro-computed tomography (micro-CT) analyses. The EDS and TOF-SIMS results indicated that high calcium intensity was detected in both the upper and lower incisors of untreated rats. Micro-CT analysis corresponded closely with spectral data in which an enhanced dental mass was calculated in intact animals. However, following SD, both calcium expression and the dental mass were remarkably decreased to nearly half those of the untreated values. Because SD plays a detrimental role in impairing dental structure, establishing satisfactory sleep behavior would therefore serve as a crucial strategy for preventing or improving prevalent dental dysfunctions.

  13. Combined two-photon laser-scanning microscopy and spectral microCT X-ray imaging to characterize the cellular signature and evolution of microstroke foci.

    PubMed

    Kirchhoff, F; Debarbieux, F; Kronland-Martinet, Carine; Cojocaru, G R; Popa-Wagner, A

    2012-01-01

    Occlusive brain ischemia and micro-strokes are the most frequent brain pathologies, particularly in older patients and a major cause of dementia. Currently, we are missing appropriate methodology to study micro-strokes in experimental animals. In vivo two-photon laser-scanning microscopy (2P-LSM) and transgenic mouse models expressing cell type specific reporters have been used to examine ischemia-related insults, e.g. perturbations of neuronal process morphology and local blood flow in the MCAO - middle cerebral artery occlusion-model. Glia and pericytes can be visualized by selective fluorescent protein expression, e.g. astrocytes by their cyan-fluorescent ECFP, pericytes by red-fluorescent tdtomato and microglia by green fluorescent EGFP expression. In these mice, the breakdown of the blood brain barrier and the immediate as well as long-term cellular responses can be monitored. A new prototype of microCT incorporating a fast X-ray XPAD3 camera has been recently set up to allow cerebral angiography at high sampling rate. Preliminary data indicate that it is useful to monitor blood perfusion disturbance (i.e. lateralization) in the brain of tumor-bearing mice following retro-orbital injection of iodinated contrast agent. We expect this technology to be adequate to assess in real time the impact of acute stroke models on brain blood perfusion. By localizing perfusion anomalies, we will evaluate the extent of non-perfused areas and correlate these observations with subsequent behavioral deficits, and with local changes in myelin content in white matter tracks. The spectral properties of the XPAD3 detector moreover allow for the simultaneous identification and localization of several contrast agents opening the way to whole body multicolor imaging of vessels and inflammatory cells in the context of microstrokes.

  14. The combination of laser micro-boring and high resolution α-spectroscopy for the analysis of α-emitting isotopes in irradiated high-temperature-reactor fuel

    NASA Astrophysics Data System (ADS)

    Helmbold, M.; Allelein, H. J.; Koch, H. R.

    1980-02-01

    A new method for the determination of α-emitting isotopes in irradiated high-temperature-reactor fuel has been developed. By use of a laser micro-boring system it is possible to prepare extremely thin α-spectroscopy samples out of any part of the fuel with a spatial resolution of about 10 μm. The measurement of the samples with a silicon barrier detector yields α-spectra of high resolution, allowing the determination of the content of most of the heavy metal isotopes. The method can be extended to the analysis of any kind of nuclear fuel.

  15. Combined use of the non-destructive XRF and low energy micro-XRF techniques for the analysis of silvered nummi belonging to the Treasure of Misurata (Libya)

    NASA Astrophysics Data System (ADS)

    Romano, Francesco Paolo; Garraffo, Salvatore; Pappalardo, Lighea; Rizzo, Francesca

    2013-04-01

    Roman coinage underwent a severe debasement of silver during the time and the production of plated coins became a common practice for giving the impression of a high finesses of the alloy. In 294 AD, Diocletian introduced the nummus, manufactured with the same standard in all the mints by using an internal Cu-Sn-Pb-Ag core and presenting a thin silvered patina (about 2 micron) on its surface. The silver plating of the nummi have been investigated in the past and different methods have been suggested for its manufacturing (e.g. segregation during casting, chemical treatments, mercury-silvering). However, previous analyses were focused on few samples and, consequently, this technological issue remained unresolved. In the present work, the BSC-XRF (Beam Stability Controlled -XRF) and a LE-micro-XRF portable spectrometers developed at the LANDIS laboratory of IBAM-CNR and LNS-INFN in Catania (Italy), have been applied for the in-situ analysis of the silvered nummi belonging to the Misurata Treasure (Museum of Leptis Magna, El-Khomes, Libya). The treasure is composed of 108 thousand coins manufactured in 19 Imperial mints operating in the period 294-333 AD. In order to establish if, and at what extent, the mercury-silvering was used to produce the thin Ag-patina of the nummi, the non-destructive investigation was extended to 1050 well preserved coins. Measurements allowed to explore the presence of Hg and the Hg-Ag correlation at the coin surface. The portable BSC-XRF and the LE-micro XXRF techniques are suited to approach this study. A new version of the BSC-XRF spectrometer, consisting of a compact high-intensity x-ray tube (50 kV; 4 mA) coupled to a 80 mm2 SDD detector (138 eV @ 5.9 keV), was developed for the fast determination of mercury traces in a large number of coins (measurement time is 150 seconds; MDL for Hg is 100 ppm). The investigation allowed to identify the Imperial mints and the periods where the mercury-silvering were probably used. However the BSC

  16. Eupolybothrus cavernicolus Komerički & Stoev sp. n. (Chilopoda: Lithobiomorpha: Lithobiidae): the first eukaryotic species description combining transcriptomic, DNA barcoding and micro-CT imaging data.

    PubMed

    Stoev, Pavel; Komerički, Ana; Akkari, Nesrine; Liu, Shanlin; Zhou, Xin; Weigand, Alexander M; Hostens, Jeroen; Hunter, Christopher I; Edmunds, Scott C; Porco, David; Zapparoli, Marzio; Georgiev, Teodor; Mietchen, Daniel; Roberts, David; Faulwetter, Sarah; Smith, Vincent; Penev, Lyubomir

    2013-01-01

    We demonstrate how a classical taxonomic description of a new species can be enhanced by applying new generation molecular methods, and novel computing and imaging technologies. A cave-dwelling centipede, Eupolybothrus cavernicolus Komerički & Stoev sp. n. (Chilopoda: Lithobiomorpha: Lithobiidae), found in a remote karst region in Knin, Croatia, is the first eukaryotic species for which, in addition to the traditional morphological description, we provide a fully sequenced transcriptome, a DNA barcode, detailed anatomical X-ray microtomography (micro-CT) scans, and a movie of the living specimen to document important traits of its ex-situ behaviour. By employing micro-CT scanning in a new species for the first time, we create a high-resolution morphological and anatomical dataset that allows virtual reconstructions of the specimen and subsequent interactive manipulation to test the recently introduced 'cybertype' notion. In addition, the transcriptome was recorded with a total of 67,785 scaffolds, having an average length of 812 bp and N50 of 1,448 bp (see GigaDB). Subsequent annotation of 22,866 scaffolds was conducted by tracing homologs against current available databases, including Nr, SwissProt and COG. This pilot project illustrates a workflow of producing, storing, publishing and disseminating large data sets associated with a description of a new taxon. All data have been deposited in publicly accessible repositories, such as GigaScience GigaDB, NCBI, BOLD, Morphbank and Morphosource, and the respective open licenses used ensure their accessibility and re-usability. PMID:24723752

  17. Combined use of synchrotron radiation based micro-X-ray fluorescence, micro-X-ray diffraction, micro-X-ray absorption near-edge, and micro-fourier transform infrared spectroscopies for revealing an alternative degradation pathway of the pigment cadmium yellow in a painting by Van Gogh.

    PubMed

    Van der Snickt, Geert; Janssens, Koen; Dik, Joris; De Nolf, Wout; Vanmeert, Frederik; Jaroszewicz, Jacub; Cotte, Marine; Falkenberg, Gerald; Van der Loeff, Luuk

    2012-12-01

    Over the past years a number of studies have described the instability of the pigment cadmium yellow (CdS). In a previous paper we have shown how cadmium sulfide on paintings by James Ensor oxidizes to CdSO(4)·H(2)O. The degradation process gives rise to the fading of the bright yellow color and the formation of disfiguring white crystals that are present on the paint surface in approximately 50 μm sized globular agglomerations. Here, we study cadmium yellow in the painting "Flowers in a blue vase" by Vincent van Gogh. This painting differs from the Ensor case in the fact that (a) a varnish was superimposed onto the degraded paint surface and (b) the CdS paint area is entirely covered with an opaque crust. The latter obscures the yellow color completely and thus presents a seemingly more advanced state of degradation. Analysis of a cross-sectioned and a crushed sample by combining scanning microscopic X-ray diffraction (μ-XRD), microscopic X-ray absorption near-edge spectroscopy (μ-XANES), microscopic X-ray fluorescence (μ-XRF) based chemical state mapping and scanning microscopic Fourier transform infrared (μ-FT-IR) spectrometry allowed unravelling the complex alteration pathway. Although no crystalline CdSO(4) compounds were identified on the Van Gogh paint samples, we conclude that the observed degradation was initially caused by oxidation of the original CdS pigment, similar as for the previous Ensor case. However, due to the presence of an overlying varnish containing lead-based driers and oxalate ions, secondary reactions took place. In particular, it appears that upon the photoinduced oxidation of its sulfidic counterion, the Cd(2+) ions reprecipitated at the paint/varnish interface after having formed a complex with oxalate ions that themselves are considered to be degradation products of the resin and/or oil in the varnish. The SO(4)(2-) anions, for their part, found a suitable reaction partner in Pb(2+) ions stemming from a dissolved lead

  18. Combined use of synchrotron radiation based micro-X-ray fluorescence, micro-X-ray diffraction, micro-X-ray absorption near-edge, and micro-fourier transform infrared spectroscopies for revealing an alternative degradation pathway of the pigment cadmium yellow in a painting by Van Gogh.

    PubMed

    Van der Snickt, Geert; Janssens, Koen; Dik, Joris; De Nolf, Wout; Vanmeert, Frederik; Jaroszewicz, Jacub; Cotte, Marine; Falkenberg, Gerald; Van der Loeff, Luuk

    2012-12-01

    Over the past years a number of studies have described the instability of the pigment cadmium yellow (CdS). In a previous paper we have shown how cadmium sulfide on paintings by James Ensor oxidizes to CdSO(4)·H(2)O. The degradation process gives rise to the fading of the bright yellow color and the formation of disfiguring white crystals that are present on the paint surface in approximately 50 μm sized globular agglomerations. Here, we study cadmium yellow in the painting "Flowers in a blue vase" by Vincent van Gogh. This painting differs from the Ensor case in the fact that (a) a varnish was superimposed onto the degraded paint surface and (b) the CdS paint area is entirely covered with an opaque crust. The latter obscures the yellow color completely and thus presents a seemingly more advanced state of degradation. Analysis of a cross-sectioned and a crushed sample by combining scanning microscopic X-ray diffraction (μ-XRD), microscopic X-ray absorption near-edge spectroscopy (μ-XANES), microscopic X-ray fluorescence (μ-XRF) based chemical state mapping and scanning microscopic Fourier transform infrared (μ-FT-IR) spectrometry allowed unravelling the complex alteration pathway. Although no crystalline CdSO(4) compounds were identified on the Van Gogh paint samples, we conclude that the observed degradation was initially caused by oxidation of the original CdS pigment, similar as for the previous Ensor case. However, due to the presence of an overlying varnish containing lead-based driers and oxalate ions, secondary reactions took place. In particular, it appears that upon the photoinduced oxidation of its sulfidic counterion, the Cd(2+) ions reprecipitated at the paint/varnish interface after having formed a complex with oxalate ions that themselves are considered to be degradation products of the resin and/or oil in the varnish. The SO(4)(2-) anions, for their part, found a suitable reaction partner in Pb(2+) ions stemming from a dissolved lead

  19. Preventive effects of butyric acid, nicotinamide, calcium glucarate alone or in combination during the 7, 12-dimethylbenz (a) anthracene induced mouse skin tumorigenesis via modulation of K-Ras-PI3K-AKTpathway and associated micro RNAs.

    PubMed

    Tiwari, Prakash; Sahay, Satya; Pandey, Manuraj; Qadri, Syed S Y H; Gupta, Krishna P

    2016-02-01

    Skin cancer is among the most common cancers worldwide and identifiable molecular changes for early and late stage of skin tumorigenesis can suggest the better targets for its control. In this study, we investigated the status of K-Ras-PI3K-AKTpathway followed by NF-κB, cyclin D1, MMP-9 and regulatory micro RNA during 7, 12-dimethylbenz[a]anthracene (DMBA) induced mouse skin tumorigenesis and its prevention by butyric acid (BA), nicotinamide (NA) and calcium glucarate (CAG), individually or in combination with respect to time. DMBA upregulated the K-Ras, PI3K, Akt, NF-κB, cyclin D1 and MMP-9, but downregulated the PTEN in a time dependent manner. DMBA also reduced the levels of micoRNA let-7a but induced the levels of miR-21 and miR-20a as a function of time. BA, NA and CAG were found to prevent DMBA induced changes, but they were most effective when used together in a combination. Reduced let-7a and miR-211 were correlated with the overexpression of K-Ras and MMP-9. Overexpression of miR-21 and miR-20a was correlated with the down regulation of PTEN and overexpression of Cyclin D1. Collectively, the enhanced chemopreventive potential of natural compound in combination via regulation of K-Ras-PI3K-AKTpathway along with regulatory micro RNAs provide a newer and effective mean for cancer management.

  20. Preventive effects of butyric acid, nicotinamide, calcium glucarate alone or in combination during the 7, 12-dimethylbenz (a) anthracene induced mouse skin tumorigenesis via modulation of K-Ras-PI3K-AKTpathway and associated micro RNAs.

    PubMed

    Tiwari, Prakash; Sahay, Satya; Pandey, Manuraj; Qadri, Syed S Y H; Gupta, Krishna P

    2016-02-01

    Skin cancer is among the most common cancers worldwide and identifiable molecular changes for early and late stage of skin tumorigenesis can suggest the better targets for its control. In this study, we investigated the status of K-Ras-PI3K-AKTpathway followed by NF-κB, cyclin D1, MMP-9 and regulatory micro RNA during 7, 12-dimethylbenz[a]anthracene (DMBA) induced mouse skin tumorigenesis and its prevention by butyric acid (BA), nicotinamide (NA) and calcium glucarate (CAG), individually or in combination with respect to time. DMBA upregulated the K-Ras, PI3K, Akt, NF-κB, cyclin D1 and MMP-9, but downregulated the PTEN in a time dependent manner. DMBA also reduced the levels of micoRNA let-7a but induced the levels of miR-21 and miR-20a as a function of time. BA, NA and CAG were found to prevent DMBA induced changes, but they were most effective when used together in a combination. Reduced let-7a and miR-211 were correlated with the overexpression of K-Ras and MMP-9. Overexpression of miR-21 and miR-20a was correlated with the down regulation of PTEN and overexpression of Cyclin D1. Collectively, the enhanced chemopreventive potential of natural compound in combination via regulation of K-Ras-PI3K-AKTpathway along with regulatory micro RNAs provide a newer and effective mean for cancer management. PMID:26655363

  1. Dispersive micro-solid phase extraction combined with gas chromatography-chemical ionization mass spectrometry for the determination of N-nitrosamines in swimming pool water samples.

    PubMed

    Fu, Ssu-Chieh; Tzing, Shin-Hwa; Chen, Hsin-Chang; Wang, Yu-Chen; Ding, Wang-Hsien

    2012-02-01

    A simple sample pretreatment technique, dispersive micro-solid phase extraction, was applied for the extraction of N-nitrosodimethylamine (NDMA) and other four N-nitrosamines (NAs) from samples of swimming pool water. The parameters affecting the extraction efficiency were systematically investigated. The best extraction conditions involved immersing 75 mg of carbon molecular sieve, Carboxen™ 1003 (as an adsorbent), in a 50-mL water sample (pH 7.0) containing 5% sodium chloride in a sample tube. After 20 min of extraction by vigorous shaking, the adsorbent was collected on a filter and the NAs desorbed by treatment with 150 μL of dichloromethane. A 10-μL aliquot was then directly determined by large-volume injection gas chromatography with chemical ionization mass spectrometry using the selected ion storage mode. The limits of quantitation were <0.9 ng/L. The precision for these analytes, as indicated by relative standard deviations, were <8% for both intra- and inter-day analyses. Accuracy, expressed as the mean extraction recovery, was between 62% and 109%. A preliminary analysis of swimming pool water samples revealed that NDMA was present in the highest concentration, in the range from n.d. to 100 ng/L. PMID:22222914

  2. Combined Label-Free Quantitative Proteomics and microRNA Expression Analysis of Breast Cancer Unravel Molecular Differences with Clinical Implications.

    PubMed

    Gámez-Pozo, Angelo; Berges-Soria, Julia; Arevalillo, Jorge M; Nanni, Paolo; López-Vacas, Rocío; Navarro, Hilario; Grossmann, Jonas; Castaneda, Carlos A; Main, Paloma; Díaz-Almirón, Mariana; Espinosa, Enrique; Ciruelos, Eva; Fresno Vara, Juan Ángel

    2015-06-01

    Better knowledge of the biology of breast cancer has allowed the use of new targeted therapies, leading to improved outcome. High-throughput technologies allow deepening into the molecular architecture of breast cancer, integrating different levels of information, which is important if it helps in making clinical decisions. microRNA (miRNA) and protein expression profiles were obtained from 71 estrogen receptor-positive (ER(+)) and 25 triple-negative breast cancer (TNBC) samples. RNA and proteins obtained from formalin-fixed, paraffin-embedded tumors were analyzed by RT-qPCR and LC/MS-MS, respectively. We applied probabilistic graphical models representing complex biologic systems as networks, confirming that ER(+) and TNBC subtypes are distinct biologic entities. The integration of miRNA and protein expression data unravels molecular processes that can be related to differences in the genesis and clinical evolution of these types of breast cancer. Our results confirm that TNBC has a unique metabolic profile that may be exploited for therapeutic intervention. PMID:25883093

  3. Integrative Approaches for microRNA Target Prediction: Combining Sequence Information and the Paired mRNA and miRNA Expression Profiles

    PubMed Central

    Naifang, Su; Minping, Qian; Minghua, Deng

    2013-01-01

    Gene regulation is a key factor in gaining a full understanding of molecular biology. microRNA (miRNA), a novel class of non-coding RNA, has recently been found to be one crucial class of post-transactional regulators, and play important roles in cancer. One essential step to understand the regulatory effect of miRNAs is the reliable prediction of their target mRNAs. Typically, the predictions are solely based on the sequence information, which unavoidably have high false detection rates. Recently, some novel approaches are developed to predict miRNA targets by integrating the typical algorithm with the paired expression profiles of miRNA and mRNA. Here we review and discuss these integrative approaches and propose a new algorithm called HCTarget. Applying HCtarget to the expression data in multiple myeloma, we predict target genes for ten specific miRNAs. The experimental verification and a loss of function study validate our predictions. Therefore, the integrative approach is a reliable and effective way to predict miRNA targets, and could improve our comprehensive understanding of gene regulation. PMID:23467572

  4. Silencing of neurotropic flavivirus replication in the central nervous system by combining multiple microRNA target insertions in two distinct viral genome regions

    PubMed Central

    Teterina, Natalya L.; Liu, Guangping; Maximova, Olga A.; Pletnev, Alexander G.

    2014-01-01

    In recent years, microRNA-targeting has become an effective strategy for selective control of tissue-tropism and pathogenesis of both DNA and RNA viruses. Here, using a neurotropic flavivirus as a model, we demonstrate that simultaneous miRNA targeting of the viral genome in the open reading frame and 3′-noncoding regions for brain-expressed miRNAs had an additive effect and produced a more potent attenuation of the virus compared to separate targeting of those regions. Multiple miRNA co-targeting of these two distantly located regions completely abolished the virus neurotropism as no viral replication was detected in the developing brain of neonatal mice. Furthermore, no viral antigens were detected in neurons, and neuronal integrity in the brain of mice was well preserved. This miRNA co-targeting approach can be adapted for other viruses in order to minimize their replication in a cell- or tissue-type specific manner, but most importantly, to prevent virus escape from miRNA-mediated silencing. PMID:24889244

  5. Novel dispersive micro-solid-phase extraction combined with ultrahigh-performance liquid chromatography-high-resolution mass spectrometry to determine morpholine residues in citrus and apples.

    PubMed

    Chen, Dawei; Miao, Hong; Zou, Jianhong; Cao, Pei; Ma, Ning; Zhao, Yunfeng; Wu, Yongning

    2015-01-21

    This paper presents a new analytical method for the determination of morpholine residues in citrus and apples using a novel dispersive micro-solid-phase extraction (DMSPE), followed by ultrahigh-performance liquid chromatography-high-resolution mass spectrometry (UHPLC-HRMS). Samples were extracted with 1% formic acid in acetonitrile/water (1:1, v/v) and then cleaned up using the DMSPE procedure. Morpholine from the extract was adsorbed to a polymer cation exchange sorbent and eluted with ammonium hydroxide/acetonitrile (3:97, v/v) through a 1 mL syringe with a 0.22 μm nylon syringe filter. All of the samples were analyzed by UHPLC-HRMS/MS on a Waters Acquity BEH hydrophilic interaction chromatography column using 0.1% formic acid and 4 mM ammonium formate in water/acetonitrile as the mobile phase with gradient elution. The method showed good linearity (R(2) > 0.999) in the range of 1-100 μg/L for the analyte. The limit of detection and limit of quantitation values of morpholine were 2 and 5 μg/kg, respectively. The average recoveries of morpholine from the citrus and apple samples spiked at three different concentrations (5, 20, and 100 μg/kg) were in a range from 78.4 to 102.7%.

  6. A Micro-Preconcentrator Combined Olfactory Sensing System with a Micromechanical Cantilever Sensor for Detecting 2,4-Dinitrotoluene Gas Vapor.

    PubMed

    Chae, Myung-Sic; Kim, Jinsik; Yoo, Yong Kyoung; Kang, Ji Yoon; Lee, Jeong Hoon; Hwang, Kyo Seon

    2015-01-01

    Preventing unexpected explosive attacks and tracing explosion-related molecules require the development of highly sensitive gas-vapor detection systems. For that purpose, a micromechanical cantilever-based olfactory sensing system including a sample preconcentrator was developed to detect 2,4-dinitrotoluene (2,4-DNT), which is a well-known by-product of the explosive molecule trinitrotoluene (TNT) and exists in concentrations on the order of parts per billion in the atmosphere at room temperature. A peptide receptor (His-Pro-Asn-Phe-Ser-Lys-Tyr-Ile-Leu-His-Gln-Arg) that has high binding affinity for 2,4-DNT was immobilized on the surface of the cantilever sensors to detect 2,4-DNT vapor for highly selective detection. A micro-preconcentrator (µPC) was developed using Tenax-TA adsorbent to produce higher concentrations of 2,4-DNT molecules. The preconcentration was achieved via adsorption and thermal desorption phenomena occurring between target molecules and the adsorbent. The µPC directly integrated with a cantilever sensor and enhanced the sensitivity of the cantilever sensor as a pretreatment tool for the target vapor. The response was rapidly saturated within 5 min and sustained for more than 10 min when the concentrated vapor was introduced. By calculating preconcentration factor values, we verified that the cantilever sensor provides up to an eightfold improvement in sensing performance.

  7. Mesoporous silica based MCM-41 as solid-phase extraction sorbent combined with micro-liquid chromatography-quadrupole-mass spectrometry for the analysis of pharmaceuticals in waters.

    PubMed

    Dahane, S; Martínez Galera, M; Marchionni, M E; Socías Viciana, M M; Derdour, A; Gil García, M D

    2016-05-15

    This paper reports the first application of the silica based mesoporous material MCM-41 as a sorbent in solid phase extraction, to pre-concentrate pharmaceuticals of very different polarity (atenolol, nadolol, pindolol, timolol, bisoprolol, metoprolol, betaxolol, ketoprofen, naproxen, ibuprofen, diclofenac, tolfenamic acid, flufenamic acid and meclofenamic acid) in surface waters. The analytes were extracted from 100mL water samples at pH 2.0 (containing 10(-3) mol/L of sodium chloride) by passing the solution through a cartridge filled with 100 mg of MCM-41. Following elution, the pharmaceuticals were determined by micro-liquid chromatography and triple quadrupole-mass spectrometry. Two selected reaction monitoring transitions were monitored per compound, the most intense one being used for quantification and the second one for confirmation. Matrix effect was found in real waters for most analytes and was overcome using the standard addition method, which compared favorably with the matrix matched calibration method. The detection limits in solvent (acetonitrile:water 10:90, v/v) ranged from 0.01 to 1.48 μg/L and in real water extracts from 0.10 to 3.85 μg/L (0.001-0.0385 μg/L in the water samples). The quantitation limits in solvent were in the range 0.02-4.93 μg/L, whereas in real water extracts were between 0.45 and 10.00 μg/L (0.0045 and 0.1000 μg/L in the water samples). When ultrapure water samples were spiked at two concentration levels of each pharmaceutical (0.1 and 0.2 μg/L) and quantified using solvent based calibration graphs, recoveries were near 100%. However, recoveries for most pharmaceuticals were comparable or better than de described above, when river water samples (spiked at the same concentration levels) were quantified by the standard addition method and slightly worse using the matrix matched calibration method. Five real samples (two rivers, one dam and two fountain water samples) were analyzed by the developed method, atenolol

  8. Non-uniform temperature distribution in Li-ion batteries during discharge - A combined thermal imaging, X-ray micro-tomography and electrochemical impedance approach

    NASA Astrophysics Data System (ADS)

    Robinson, James B.; Darr, Jawwad A.; Eastwood, David S.; Hinds, Gareth; Lee, Peter D.; Shearing, Paul R.; Taiwo, Oluwadamilola O.; Brett, Dan J. L.

    2014-04-01

    Thermal runaway is a major cause of failure in Li-ion batteries (LIBs), and of particular concern for high energy density transport applications, where safety concerns have hampered commercialisation. A clear understanding of electro-thermal properties and how these relate to structure and operation is vital to improving thermal management of LIBs. Here a combined thermal imaging, X-ray tomography and electrochemical impedance spectroscopy (EIS) approach was applied to commercially available 18650 cells to study their thermal characteristics. Thermal imaging was used to characterise heterogeneous temperature distributions during discharge above 0.75C; the complementary information provided by 3D X-ray tomography was utilised to evaluate the internal structure of the battery and identify the regions causing heating, specifically the components of the battery cap.

  9. Multifunctional Poly(L-lactide)-Polyethylene Glycol-Grafted Graphene Quantum Dots for Intracellular MicroRNA Imaging and Combined Specific-Gene-Targeting Agents Delivery for Improved Therapeutics.

    PubMed

    Dong, Haifeng; Dai, Wenhao; Ju, Huangxian; Lu, Huiting; Wang, Shiyan; Xu, Liping; Zhou, Shu-Feng; Zhang, Yue; Zhang, Xueji

    2015-05-27

    Photoluminescent (PL) graphene quantum dots (GQDs) with large surface area and superior mechanical flexibility exhibit fascinating optical and electronic properties and possess great promising applications in biomedical engineering. Here, a multifunctional nanocomposite of poly(l-lactide) (PLA) and polyethylene glycol (PEG)-grafted GQDs (f-GQDs) was proposed for simultaneous intracellular microRNAs (miRNAs) imaging analysis and combined gene delivery for enhanced therapeutic efficiency. The functionalization of GQDs with PEG and PLA imparts the nanocomposite with super physiological stability and stable photoluminescence over a broad pH range, which is vital for cell imaging. Cell experiments demonstrate the f-GQDs excellent biocompatibility, lower cytotoxicity, and protective properties. Using the HeLa cell as a model, we found the f-GQDs effectively delivered a miRNA probe for intracellular miRNA imaging analysis and regulation. Notably, the large surface of GQDs was capable of simultaneous adsorption of agents targeting miRNA-21 and survivin, respectively. The combined conjugation of miRNA-21-targeting and survivin-targeting agents induced better inhibition of cancer cell growth and more apoptosis of cancer cells, compared with conjugation of agents targeting miRNA-21 or survivin alone. These findings highlight the promise of the highly versatile multifunctional nanocomposite in biomedical application of intracellular molecules analysis and clinical gene therapeutics.

  10. Fabrication of long-focal-length plano-convex microlens array by combining the micro-milling and injection molding processes.

    PubMed

    Chen, Lei; Kirchberg, Stefan; Jiang, Bing-Yan; Xie, Lei; Jia, Yun-Long; Sun, Lei-Lei

    2014-11-01

    A uniform plano-convex spherical microlens array with a long focal length was fabricated by combining the micromilling and injection molding processes in this work. This paper presents a quantitative study of the injection molding process parameters on the uniformity of the height of the microlenses. The variation of the injection process parameters, i.e., barrel temperature, mold temperature, injection speed, and packing pressure, was found to have a significant effect on the uniformity of the height of the microlenses, especially the barrel temperature. The filling-to-packing switchover point is also critical to the uniformity of the height of the microlenses. The optimal uniformity was achieved when the polymer melts completely filled the mold cavity, or even a little excessively filled the cavity, during the filling stage. In addition, due to the filling resistance, the practical filling-to-packing switchover point can vary with the change of the filling processing conditions and lead to a non-negligible effect on the uniformity of the height of the microlenses. Furthermore, the effect of injection speed on the uniformity of the height of the microlenses was analyzed in detail. The results indicated that the effect of injection speed on the uniformity of the height of the microlenses is mainly attributed to the two functions of injection speed: transferring the filling-to-packing switchover point and affecting the distribution of residual flow stress in the polymer melt. PMID:25402902

  11. In situ investigation of the surface silvering of late Roman coins by combined use of high energy broad-beam and low energy micro-beam X-ray fluorescence techniques

    NASA Astrophysics Data System (ADS)

    Romano, F. P.; Garraffo, S.; Pappalardo, L.; Rizzo, F.

    2012-07-01

    The compositional analysis of archeological metals performed with the X-ray Fluorescence technique (XRF) provides information on the ancient technology. One of the most interesting case-study concerns the techniques used by Romans for silvering the surface of coins. Different metallurgical processes have been suggested in previous studies. Recently the investigation has been addressed to the mercury-silvering and to its possible use in the mass-production of coins minted during the late period (after 294 AD). In the present paper the non-destructive investigation of the silvering process used for manufacturing the Roman nummi - the important typology of coin introduced by Diocletian in his monetary reform - is approached by the combined use of the standard X-Ray Fluorescence (XRF) and the low energy micro-X-Ray Fluorescence (LE-μXRF) portable methods. The research was focused on the systematic determination of the mercury presence in a large number of samples and on its correlation with silver in the surface of the coins. 1041 Roman nummi belonging to the Misurata Treasure were analyzed in situ, at the Leptis Magna Museum (Al Khums, Libya). The treasure, composed of about 108 thousand silvered coins, gives the unique opportunity to study the Roman coinage in a wide interval of time (about 40 years in the period 294-333 AD) and in almost all the imperial mints operating in the Roman world.

  12. MicroED data collection and processing

    SciTech Connect

    Hattne, Johan; Reyes, Francis E.; Nannenga, Brent L.; Shi, Dan; Cruz, M. Jason de la; Leslie, Andrew G. W.; Gonen, Tamir

    2015-07-01

    The collection and processing of MicroED data are presented. MicroED, a method at the intersection of X-ray crystallography and electron cryo-microscopy, has rapidly progressed by exploiting advances in both fields and has already been successfully employed to determine the atomic structures of several proteins from sub-micron-sized, three-dimensional crystals. A major limiting factor in X-ray crystallography is the requirement for large and well ordered crystals. By permitting electron diffraction patterns to be collected from much smaller crystals, or even single well ordered domains of large crystals composed of several small mosaic blocks, MicroED has the potential to overcome the limiting size requirement and enable structural studies on difficult-to-crystallize samples. This communication details the steps for sample preparation, data collection and reduction necessary to obtain refined, high-resolution, three-dimensional models by MicroED, and presents some of its unique challenges.

  13. Metal-organic framework MIL-101(Cr) as a sorbent of porous membrane-protected micro-solid-phase extraction for the analysis of six phthalate esters from drinking water: a combination of experimental and computational study.

    PubMed

    Wang, Ting; Wang, Jian; Zhang, Conglu; Yang, Zhao; Dai, Xinpeng; Cheng, Maosheng; Hou, Xiaohong

    2015-08-01

    An attractive metal-organic framework (MOF) MIL-101(Cr) material was synthesized at the nanoscale and applied as a sorbent in the porous membrane-protected micro-solid-phase extraction (μ-SPE) device for the pre-concentration of phthalate esters (PAEs) in drinking water samples for the first time. Parameters influencing the extraction efficiency, such as the selection of sorbent materials, pH adjustment, the effect of salt, magnetic-stirring extraction time, the desorption solvent and the desorption time, were investigated. Under the optimum conditions, the limits of detection from gas chromatography-mass spectrometric analysis for PAEs varied from 0.004 to 0.02 μg L(-1). The linear ranges were from 0.1 to 50 μg L(-1) or from 0.2 to 50 μg L(-1) for the analytes with the relative standard deviations fluctuating from 0.8 to 10.9% (n = 5). The enrichment factors (EFs) for the target PAEs were varied from 143 to 187. MIL-101(Cr) exhibited remarkable advantages compared to activated carbon and MIL-100(Fe). On the other hand, the computational method was first used to predict the adsorption of MIL-101(Cr) towards PAEs. The molecular interactions and the free binding energies between MIL-101(Cr) and PAEs were observed and calculated in terms of the molecular modeling method. MIL-101(Cr) showed high potential in the analysis of PAEs at trace levels in drinking water. The computational result was consistent with the detected enrichment factors. The computational modeling accurately predicted the extraction efficiency of MOF-based material towards the target analytes. Therefore, the combination of experimental and computational study provided a new strategy on the trace contaminant analysis. PMID:26076497

  14. Metal-organic framework MIL-101(Cr) as a sorbent of porous membrane-protected micro-solid-phase extraction for the analysis of six phthalate esters from drinking water: a combination of experimental and computational study.

    PubMed

    Wang, Ting; Wang, Jian; Zhang, Conglu; Yang, Zhao; Dai, Xinpeng; Cheng, Maosheng; Hou, Xiaohong

    2015-08-01

    An attractive metal-organic framework (MOF) MIL-101(Cr) material was synthesized at the nanoscale and applied as a sorbent in the porous membrane-protected micro-solid-phase extraction (μ-SPE) device for the pre-concentration of phthalate esters (PAEs) in drinking water samples for the first time. Parameters influencing the extraction efficiency, such as the selection of sorbent materials, pH adjustment, the effect of salt, magnetic-stirring extraction time, the desorption solvent and the desorption time, were investigated. Under the optimum conditions, the limits of detection from gas chromatography-mass spectrometric analysis for PAEs varied from 0.004 to 0.02 μg L(-1). The linear ranges were from 0.1 to 50 μg L(-1) or from 0.2 to 50 μg L(-1) for the analytes with the relative standard deviations fluctuating from 0.8 to 10.9% (n = 5). The enrichment factors (EFs) for the target PAEs were varied from 143 to 187. MIL-101(Cr) exhibited remarkable advantages compared to activated carbon and MIL-100(Fe). On the other hand, the computational method was first used to predict the adsorption of MIL-101(Cr) towards PAEs. The molecular interactions and the free binding energies between MIL-101(Cr) and PAEs were observed and calculated in terms of the molecular modeling method. MIL-101(Cr) showed high potential in the analysis of PAEs at trace levels in drinking water. The computational result was consistent with the detected enrichment factors. The computational modeling accurately predicted the extraction efficiency of MOF-based material towards the target analytes. Therefore, the combination of experimental and computational study provided a new strategy on the trace contaminant analysis.

  15. Characterization of calcium and zinc spatial distributions at the fibrocartilage zone of bone-tendon junction by synchrotron radiation-based micro X-ray fluorescence analysis combined with backscattered electron imaging

    NASA Astrophysics Data System (ADS)

    Lu, Hongbin; Chen, Can; Wang, Zhanwen; Qu, Jin; Xu, Daqi; Wu, Tianding; Cao, Yong; Zhou, Jingyong; Zheng, Cheng; Hu, Jianzhong

    2015-09-01

    Tendon attaches to bone through a functionally graded fibrocartilage zone, including uncalcified fibrocartilage (UF), tidemark (TM) and calcified fibrocartilage (CF). This transition zone plays a pivotal role in relaxing load transfer between tendon and bone, and serves as a boundary between otherwise structurally and functionally distinct tissue types. Calcium and zinc are believed to play important roles in the normal growth, mineralization, and repair of the fibrocartilage zone of bone-tendon junction (BTJ). However, spatial distributions of calcium and zinc at the fibrocartilage zone of BTJ and their distribution-function relationship are not totally understood. Thus, synchrotron radiation-based micro X-ray fluorescence analysis (SR-μXRF) in combination with backscattered electron imaging (BEI) was employed to characterize the distributions of calcium and zinc at the fibrocartilage zone of rabbit patella-patellar tendon complex (PPTC). For the first time, the unique distributions of calcium and zinc at the fibrocartilage zone of the PPTC were clearly mapped by this method. The distributions of calcium and zinc at the fibrocartilage zone of the PPTC were inhomogeneous. A significant accumulation of zinc was exhibited in the transition region between UF and CF. The highest zinc content (3.17 times of that of patellar tendon) was found in the TM of fibrocartilage zone. The calcium content began to increase near the TM and increased exponentially across the calcified fibrocartilage region towards the patella. The highest calcium content (43.14 times of that of patellar tendon) was in the transitional zone of calcified fibrocartilage region and the patella, approximately 69 μm from the location with the highest zinc content. This study indicated, for the first time, that there is a differential distribution of calcium and zinc at the fibrocartilage zone of PPTC. These observations reveal new insights into region-dependent changes across the fibrocartilage zone of

  16. Proteomic analysis of cellular soluble proteins from human bronchial smooth muscle cells by combining nondenaturing micro 2DE and quantitative LC-MS/MS. 2. Similarity search between protein maps for the analysis of protein complexes.

    PubMed

    Jin, Ya; Yuan, Qi; Zhang, Jun; Manabe, Takashi; Tan, Wen

    2015-09-01

    Human bronchial smooth muscle cell soluble proteins were analyzed by a combined method of nondenaturing micro 2DE, grid gel-cutting, and quantitative LC-MS/MS and a native protein map was prepared for each of the identified 4323 proteins [1]. A method to evaluate the degree of similarity between the protein maps was developed since we expected the proteins comprising a protein complex would be separated together under nondenaturing conditions. The following procedure was employed using Excel macros; (i) maps that have three or more squares with protein quantity data were selected (2328 maps), (ii) within each map, the quantity values of the squares were normalized setting the highest value to be 1.0, (iii) in comparing a map with another map, the smaller normalized quantity in two corresponding squares was taken and summed throughout the map to give an "overlap score," (iv) each map was compared against all the 2328 maps and the largest overlap score, obtained when a map was compared with itself, was set to be 1.0 thus providing 2328 "overlap factors," (v) step (iv) was repeated for all maps providing 2328 × 2328 matrix of overlap factors. From the matrix, protein pairs that showed overlap factors above 0.65 from both protein sides were selected (431 protein pairs). Each protein pair was searched in a database (UniProtKB) on complex formation and 301 protein pairs, which comprise 35 protein complexes, were found to be documented. These results demonstrated that native protein maps and their similarity search would enable simultaneous analysis of multiple protein complexes in cells.

  17. MicroED data collection and processing.

    PubMed

    Hattne, Johan; Reyes, Francis E; Nannenga, Brent L; Shi, Dan; de la Cruz, M Jason; Leslie, Andrew G W; Gonen, Tamir

    2015-07-01

    MicroED, a method at the intersection of X-ray crystallography and electron cryo-microscopy, has rapidly progressed by exploiting advances in both fields and has already been successfully employed to determine the atomic structures of several proteins from sub-micron-sized, three-dimensional crystals. A major limiting factor in X-ray crystallography is the requirement for large and well ordered crystals. By permitting electron diffraction patterns to be collected from much smaller crystals, or even single well ordered domains of large crystals composed of several small mosaic blocks, MicroED has the potential to overcome the limiting size requirement and enable structural studies on difficult-to-crystallize samples. This communication details the steps for sample preparation, data collection and reduction necessary to obtain refined, high-resolution, three-dimensional models by MicroED, and presents some of its unique challenges. PMID:26131894

  18. MicroED data collection and processing

    PubMed Central

    Hattne, Johan; Reyes, Francis E.; Nannenga, Brent L.; Shi, Dan; de la Cruz, M. Jason; Leslie, Andrew G. W.; Gonen, Tamir

    2015-01-01

    MicroED, a method at the intersection of X-ray crystallography and electron cryo-microscopy, has rapidly progressed by exploiting advances in both fields and has already been successfully employed to determine the atomic structures of several proteins from sub-micron-sized, three-dimensional crystals. A major limiting factor in X-ray crystallography is the requirement for large and well ordered crystals. By permitting electron diffraction patterns to be collected from much smaller crystals, or even single well ordered domains of large crystals composed of several small mosaic blocks, MicroED has the potential to overcome the limiting size requirement and enable structural studies on difficult-to-crystallize samples. This communication details the steps for sample preparation, data collection and reduction necessary to obtain refined, high-resolution, three-dimensional models by MicroED, and presents some of its unique challenges. PMID:26131894

  19. A study of lubrication, processing conditions, and material combinations that affect the wear of micro-textured-carbide coated cobalt-chromium-molybdenum alloy surfaces used for artificial joints implants

    NASA Astrophysics Data System (ADS)

    Ettienne-Modeste, Geriel A.

    Total joint replacement remains one of the most successful treatments for arthritis. The most common materials used for artificial joints are metals (e.g., cobalt-chrome alloys or titanium alloys), which articulate against ultra-high molecular weight polyethylene. Wear related failures of artificial joints may be reduced with the use of novel micro-textured carbide surfaces. The micro-textured carbide surfaces were deposited on a CoCrMo alloy using microwave plasma-assisted chemical vapor deposition. Wear tests were conducted to determine wear mechanisms and properties of the micro-textured surfaces. The research presented in this thesis addresses: (1) rheolgoical behavior of bovine calf serum with and without antibacterial agents to determine whether they can be used as appropriate models for synovial fluid, (2) the wear behavior of the micro-textured CoCrMo surface system, and (3) the mechanical and material properties of the micro-textured CoCrMo alloy surface relevant to wear performance. The rheological studies showed that the apparent viscosity of bovine calf serum increased with an increase in concentration before and after the serum was used for wear testing. The wear analysis showed that the processing conditions (2hr deposition vs. 4hr deposition times) affected the wear properties. The 2hr carbide-on-carbide lubricated in 50% BCS produced the lowest wear factor and rate for the five wear couple systems containing the carbide disk or plate material. Greater wear was produced in serum without penicillin/streptomycin (P/S) compared to the serum containing P/S. A greater carbide coating thickness 10 (micrometers) was produced during the 4hr deposition time than for the 2hr deposition (˜3mum). The nano-hardness value was higher than the micro-hardness for both the 4hr and 2hr carbide surfaces. The micro-hardness results of the worn carbide surfaces showed that an increase in BCS concentration from 0% to 100% increased the micro-hardness (HV) for carbide

  20. High-efficiency approach for fabricating MTE rotor by micro-EDM and micro-extrusion

    NASA Astrophysics Data System (ADS)

    Geng, Xuesong; Chi, Guanxin; Wang, Yukui; Wang, Zhenlong

    2014-07-01

    Micro-gas turbine engine (MTE) rotor is an important indicator of its property, therefore, the manufacturing technology of the microminiature rotor has become a hot area of research at home and abroad. At present, the main manufacturing technologies of the MTE rotor are directed forming fabrication technologies. However, these technologies have a series of problems, such as complex processing technology high manufacturing cost, and low processing efficiency, and so on. This paper takes advantage of micro electric discharge machining (micro-EDM) in the field of microminiature molds manufacturing, organizes many processing technologies of micro-EDM reasonably to improve processing accuracy, presents an integrated micro-EDM technology and its process flow to fabricate MTE rotor die, and conducts a series of experiments to verify efficiency of this integrated micro-EDM. The experiments results show that the MTE rotor die has sharp outline and ensure the good consistency of MTE rotor blades. Meanwhile, the MTE rotor die is applied to micro extrusion equipment, and technologies of micro-EDM and micro forming machining are combined based on the idea of the molds manufacturing, so the MTE rotor with higher aspect ratio and better consistency of blades can be manufactured efficiently. This research presents an integrated micro-EDM technology and its process flow, which promotes the practical process of MTE effectively.

  1. Micro-objective manipulated with optical tweezers

    SciTech Connect

    Sasaki, M.; Kurosawa, T.; Hane, K.

    1997-02-01

    A microscope is described that uses a {mu}m-sized ball lens, which is here termed micro-objective, manipulated with optical tweezers to image the side view of the arbitrary region of a sample. Since this micro-objective is small in size, it can go into a concave region to produce a local image of the inside which the conventional microscope cannot observe. Preliminary results show good lens performance from the micro-objective when combined with optical tweezers. {copyright} {ital 1997 American Institute of Physics.}

  2. COMBINES AND COMBINING.

    ERIC Educational Resources Information Center

    RIDENOUR, HARLAN E.

    THROUGH THE USE OF THIS MANUAL, VOCATIONAL AGRICULTURE STUDENTS WITH OCCUPATIONAL INTEREST IN GRAIN FARMING AND CUSTOM COMBINE OPERATION MAY GAIN KNOWLEDGE ABOUT THE BASIC DESIGN AND OPERATION OF COMBINES. DEVELOPMENT BY A STATE CURRICULUM MATERIALS DIRECTOR INCLUDED CONSULTATION WITH ENGINEERS, TRIAL, AND REVISION. OBJECTIVES ARE STATED IN TERMS…

  3. High range resolution micro-Doppler analysis

    NASA Astrophysics Data System (ADS)

    Cammenga, Zachary A.; Smith, Graeme E.; Baker, Christopher J.

    2015-05-01

    This paper addresses use of the micro-Doppler effect and the use of high range-resolution profiles to observe complex targets in complex target scenes. The combination of micro-Doppler and high range-resolution provides the ability to separate the motion of complex targets from one another. This ability leads to the differentiation of targets based on their micro-Doppler signatures. Without the high-range resolution, this would not be possible because the individual signatures would not be separable. This paper also addresses the use of the micro-Doppler information and high range-resolution profiles to generate an approximation of the scattering properties of a complex target. This approximation gives insight into the structure of the complex target and, critically, is created without using a pre-determined target model.

  4. Micro-laser

    DOEpatents

    Hutchinson, Donald P.; Richards, Roger K.

    2003-07-22

    A micro-laser is disclosed which includes a waveguide, a first and a second subwavelength resonant grating in the waveguide, and at least one photonic band gap resonant structure (PBG) in the waveguide and at least one amplifying medium in the waveguide. PBG features are positioned between the first and second subwavelength resonant gratings and allow introduction of amplifying mediums into the highly resonant guided micro-laser microcavity. The micro-laser may be positioned on a die of a bulk substrate material with one or more electronic and optical devices and may be communicably connected to the same. A method for fabricating a micro-laser is disclosed. A method for tuning the micro-laser is also disclosed. The micro-laser may be used as an optical regenerator, or a light source for data transfer or for optical computing.

  5. MicroSight Optics

    ScienceCinema

    None

    2016-07-12

    MicroSight is an innovative gunsight technology that allows a marksman's eye to focus on both the front gunsight and the intended target. The MicroSight improves both firearm safety and performance by imaging two objects at different focal distances. The MicroSight was developed at Idaho National Laboratory, and has been licensed by Apollo Optical Systems. You can learn more about INL's research programs at http://www.facebook.com/idahonationallaboratory.

  6. MicroSight Optics

    SciTech Connect

    2010-01-01

    MicroSight is an innovative gunsight technology that allows a marksman's eye to focus on both the front gunsight and the intended target. The MicroSight improves both firearm safety and performance by imaging two objects at different focal distances. The MicroSight was developed at Idaho National Laboratory, and has been licensed by Apollo Optical Systems. You can learn more about INL's research programs at http://www.facebook.com/idahonationallaboratory.

  7. Micro-Organ Device

    NASA Technical Reports Server (NTRS)

    Gonda, Steve R. (Inventor); Chang, Robert C. (Inventor); Starly, Binil (Inventor); Culbertson, Christopher (Inventor); Holtorf, Heidi L. (Inventor); Sun, Wei (Inventor); Leslie, Julia (Inventor)

    2013-01-01

    A method for fabricating a micro-organ device comprises providing a microscale support having one or more microfluidic channels and one or more micro-chambers for housing a micro-organ and printing a micro-organ on the microscale support using a cell suspension in a syringe controlled by a computer-aided tissue engineering system, wherein the cell suspension comprises cells suspended in a solution containing a material that functions as a three-dimensional scaffold. The printing is performed with the computer-aided tissue engineering system according to a particular pattern. The micro-organ device comprises at least one micro-chamber each housing a micro-organ; and at least one microfluidic channel connected to the micro-chamber, wherein the micro-organ comprises cells arranged in a configuration that includes microscale spacing between portions of the cells to facilitate diffusion exchange between the cells and a medium supplied from the at least one microfluidic channel.

  8. Micro-organ device

    NASA Technical Reports Server (NTRS)

    Gonda, Steve R. (Inventor); von Gustedt-Gonda, legal representative, Iris (Inventor); Chang, Robert C. (Inventor); Starly, Binil (Inventor); Culbertson, Christopher (Inventor); Holtorf, Heidi L. (Inventor); Sun, Wei (Inventor); Leslie, Julia (Inventor)

    2013-01-01

    A method for fabricating a micro-organ device comprises providing a microscale support having one or more microfluidic channels and one or more micro-chambers for housing a micro-organ and printing a micro-organ on the microscale support using a cell suspension in a syringe controlled by a computer-aided tissue engineering system, wherein the cell suspension comprises cells suspended in a solution containing a material that functions as a three-dimensional scaffold. The printing is performed with the computer-aided tissue engineering system according to a particular pattern. The micro-organ device comprises at least one micro-chamber each housing a micro-organ; and at least one microfluidic channel connected to the micro-chamber, wherein the micro-organ comprises cells arranged in a configuration that includes microscale spacing between portions of the cells to facilitate diffusion exchange between the cells and a medium supplied from the at least one microfluidic channel.

  9. High speed micro scanner for 3D in-volume laser micro processing

    NASA Astrophysics Data System (ADS)

    Schaefer, D.; Gottmann, J.; Hermans, M.; Ortmann, J.; Kelbassa, I.

    2013-03-01

    Using an in-house developed micro scanner three-dimensional micro components and micro fluidic devices in fused silica are realized using the ISLE process (in-volume selective laser-induced etching). With the micro scanner system the potential of high average power femtosecond lasers (P > 100 W) is exploited by the fabrication of components with micrometer precision at scan speeds of several meters per second. A commercially available galvanometer scanner is combined with an acousto-optical and/or electro-optical beam deflector and translation stages. For focusing laser radiation high numerical aperture microscope objectives (NA > 0.3) are used generating a focal volume of a few cubic micrometers. After laser exposure the materials are chemically wet etched in aqueous solution. The laser-exposed material is etched whereas the unexposed material remains nearly unchanged. Using the described technique called ISLE the fabrication of three-dimensional micro components, micro holes, cuts and channels is possible with high average power femtosecond lasers resulting in a reduced processing time for exposure. By developing the high speed micro scanner up-scaling of the ISLE process is demonstrated. The fabricated components made out of glass can be applied in various markets like biological and medical diagnostics as well as in micro mechanics.

  10. Micro-Kelvin cold molecules.

    SciTech Connect

    Strecker, Kevin E.; Chandler, David W.

    2009-10-01

    We have developed a novel experimental technique for direct production of cold molecules using a combination of techniques from atomic optical and molecular physics and physical chemistry. The ability to produce samples of cold molecules has application in a broad spectrum of technical fields high-resolution spectroscopy, remote sensing, quantum computing, materials simulation, and understanding fundamental chemical dynamics. Researchers around the world are currently exploring many techniques for producing samples of cold molecules, but to-date these attempts have offered only limited success achieving milli-Kelvin temperatures with low densities. This Laboratory Directed Research and Development project is to develops a new experimental technique for producing micro-Kelvin temperature molecules via collisions with laser cooled samples of trapped atoms. The technique relies on near mass degenerate collisions between the molecule of interest and a laser cooled (micro-Kelvin) atom. A subset of collisions will transfer all (nearly all) of the kinetic energy from the 'hot' molecule, cooling the molecule at the expense of heating the atom. Further collisions with the remaining laser cooled atoms will thermally equilibrate the molecules to the micro-Kelvin temperature of the laser-cooled atoms.

  11. The Use of Light/Chemically Hardened Polymethylmethacrylate, Polyhydroxylethylmethacrylate, and Calcium Hydroxide Graft Material in Combination With Polyanhydride Around Implants and Extraction Sockets in Minipigs: Part II: Histologic and Micro-CT Evaluations

    PubMed Central

    Hasturk, Hatice; Kantarci, Alpdogan; Ghattas, Mazen; Dangaria, Smit J.; Abdallah, Rima; Morgan, Elise F.; Diekwisch, Thomas G.H.; Ashman, Arthur; Van Dyke, Thomas

    2015-01-01

    Background This report is the second part of the previously published study on the impact of light/chemical hardening technology and a newly formulated composite graft material for crestal augmentation during immediate implant placement. Methods A total of 48 implants were placed into the sockets of the mesial roots of freshly extracted mandibular premolar teeth in three minipigs. Crestal areas and intrabony spaces were randomly augmented with light-hardened graft materials including a composite graft consisting of polymethylmethacrylate, polyhydroxylethylmethacrylate, and calcium hydroxide (PPCH) plus polyanhydride (PA); PPCH graft; and PA graft, or left untreated. Distal sockets not receiving implants and the sockets of first molars (n = 60) were randomly treated with one of the graft materials or left empty. In addition, two molar sockets were treated with the original PPCH graft material. Quantitative microcomputed tomography (micro-CT) was used to assess alveolar bone structure and tissue compositions. Histologic evaluations included descriptive histology to assess the peri-implant wound healing, as well as histomorphometric measurements to determine bone-to-implant contact (BIC). Results Both trabecular and cortical bone measurements by micro-CT did not reveal any significant differences among the groups. Sites augmented with PPCH+PA resulted in significantly greater BIC surface than PPCH alone and no-graft-treated implants (P <0.05) histologically. Stained ground sections showed complete bone formation between bone and implant surface in the PPCH+PA group, whereas sites without augmentation showed large gaps between bone and implant surfaces, indicating a slower bone apposition and less BIC surface compared to all other groups. Similar to implant sections, all materials showed positive outcome on trabecular and cortical bone formation in extraction sockets with an intact crestal cortical bone. Conclusion Histologic evaluations supported the previous findings

  12. Search for Bs0 --> micro+ micro- and B0 --> micro+ micro- decays with 2 fb-1 of pp collisions.

    PubMed

    Aaltonen, T; Adelman, J; Akimoto, T; Albrow, M G; Alvarez González, B; Amerio, S; Amidei, D; Anastassov, A; Annovi, A; Antos, J; Aoki, M; Apollinari, G; Apresyan, A; Arisawa, T; Artikov, A; Ashmanskas, W; Attal, A; Aurisano, A; Azfar, F; Azzi-Bacchetta, P; Azzurri, P; Bacchetta, N; Badgett, W; Barbaro-Galtieri, A; Barnes, V E; Barnett, B A; Baroiant, S; Bartsch, V; Bauer, G; Beauchemin, P-H; Bedeschi, F; Bednar, P; Behari, S; Bellettini, G; Bellinger, J; Belloni, A; Benjamin, D; Beretvas, A; Beringer, J; Berry, T; Bhatti, A; Binkley, M; Bisello, D; Bizjak, I; Blair, R E; Blocker, C; Blumenfeld, B; Bocci, A; Bodek, A; Boisvert, V; Bolla, G; Bolshov, A; Bortoletto, D; Boudreau, J; Boveia, A; Brau, B; Bridgeman, A; Brigliadori, L; Bromberg, C; Brubaker, E; Budagov, J; Budd, H S; Budd, S; Burkett, K; Busetto, G; Bussey, P; Buzatu, A; Byrum, K L; Cabrera, S; Campanelli, M; Campbell, M; Canelli, F; Canepa, A; Carlsmith, D; Carosi, R; Carrillo, S; Carron, S; Casal, B; Casarsa, M; Castro, A; Catastini, P; Cauz, D; Cavalli-Sforza, M; Cerri, A; Cerrito, L; Chang, S H; Chen, Y C; Chertok, M; Chiarelli, G; Chlachidze, G; Chlebana, F; Cho, K; Chokheli, D; Chou, J P; Choudalakis, G; Chuang, S H; Chung, K; Chung, W H; Chung, Y S; Ciobanu, C I; Ciocci, M A; Clark, A; Clark, D; Compostella, G; Convery, M E; Conway, J; Cooper, B; Copic, K; Cordelli, M; Cortiana, G; Crescioli, F; Cuenca Almenar, C; Cuevas, J; Culbertson, R; Cully, J C; Dagenhart, D; Datta, M; Davies, T; de Barbaro, P; De Cecco, S; Deisher, A; De Lentdecker, G; De Lorenzo, G; Dell'orso, M; Demortier, L; Deng, J; Deninno, M; De Pedis, D; Derwent, P F; Di Giovanni, G P; Dionisi, C; Di Ruzza, B; Dittmann, J R; D'Onofrio, M; Donati, S; Dong, P; Donini, J; Dorigo, T; Dube, S; Efron, J; Erbacher, R; Errede, D; Errede, S; Eusebi, R; Fang, H C; Farrington, S; Fedorko, W T; Feild, R G; Feindt, M; Fernandez, J P; Ferrazza, C; Field, R; Flanagan, G; Forrest, R; Forrester, S; Franklin, M; Freeman, J C; Furic, I; Gallinaro, M; Galyardt, J; Garberson, F; Garcia, J E; Garfinkel, A F; Genser, K; Gerberich, H; Gerdes, D; Giagu, S; Giakoumopolou, V; Giannetti, P; Gibson, K; Gimmell, J L; Ginsburg, C M; Giokaris, N; Giordani, M; Giromini, P; Giunta, M; Glagolev, V; Glenzinski, D; Gold, M; Goldschmidt, N; Golossanov, A; Gomez, G; Gomez-Ceballos, G; Goncharov, M; González, O; Gorelov, I; Goshaw, A T; Goulianos, K; Gresele, A; Grinstein, S; Grosso-Pilcher, C; Grundler, U; Guimaraes da Costa, J; Gunay-Unalan, Z; Haber, C; Hahn, K; Hahn, S R; Halkiadakis, E; Hamilton, A; Han, B-Y; Han, J Y; Handler, R; Happacher, F; Hara, K; Hare, D; Hare, M; Harper, S; Harr, R F; Harris, R M; Hartz, M; Hatakeyama, K; Hauser, J; Hays, C; Heck, M; Heijboer, A; Heinemann, B; Heinrich, J; Henderson, C; Herndon, M; Heuser, J; Hewamanage, S; Hidas, D; Hill, C S; Hirschbuehl, D; Hocker, A; Hou, S; Houlden, M; Hsu, S-C; Huffman, B T; Hughes, R E; Husemann, U; Huston, J; Incandela, J; Introzzi, G; Iori, M; Ivanov, A; Iyutin, B; James, E; Jayatilaka, B; Jeans, D; Jeon, E J; Jindariani, S; Johnson, W; Jones, M; Joo, K K; Jun, S Y; Jung, J E; Junk, T R; Kamon, T; Kar, D; Karchin, P E; Kato, Y; Kephart, R; Kerzel, U; Khotilovich, V; Kilminster, B; Kim, D H; Kim, H S; Kim, J E; Kim, M J; Kim, S B; Kim, S H; Kim, Y K; Kimura, N; Kirsch, L; Klimenko, S; Klute, M; Knuteson, B; Ko, B R; Koay, S A; Kondo, K; Kong, D J; Konigsberg, J; Korytov, A; Kotwal, A V; Kraus, J; Kreps, M; Kroll, J; Krumnack, N; Kruse, M; Krutelyov, V; Kubo, T; Kuhlmann, S E; Kuhr, T; Kulkarni, N P; Kusakabe, Y; Kwang, S; Laasanen, A T; Lai, S; Lami, S; Lammel, S; Lancaster, M; Lander, R L; Lannon, K; Lath, A; Latino, G; Lazzizzera, I; Lecompte, T; Lee, J; Lee, J; Lee, Y J; Lee, S W; Lefèvre, R; Leonardo, N; Leone, S; Levy, S; Lewis, J D; Lin, C; Lin, C S; Linacre, J; Lindgren, M; Lipeles, E; Lister, A; Litvintsev, D O; Liu, T; Lockyer, N S; Loginov, A; Loreti, M; Lovas, L; Lu, R-S; Lucchesi, D; Lueck, J; Luci, C; Lujan, P; Lukens, P; Lungu, G; Lyons, L; Lys, J; Lysak, R; Lytken, E; Mack, P; Macqueen, D; Madrak, R; Maeshima, K; Makhoul, K; Maki, T; Maksimovic, P; Malde, S; Malik, S; Manca, G; Manousakis, A; Margaroli, F; Marino, C; Marino, C P; Martin, A; Martin, M; Martin, V; Martínez, M; Martínez-Ballarín, R; Maruyama, T; Mastrandrea, P; Masubuchi, T; Mattson, M E; Mazzanti, P; McFarland, K S; McIntyre, P; McNulty, R; Mehta, A; Mehtala, P; Menzemer, S; Menzione, A; Merkel, P; Mesropian, C; Messina, A; Miao, T; Miladinovic, N; Miles, J; Miller, R; Mills, C; Milnik, M; Mitra, A; Mitselmakher, G; Miyake, H; Moed, S; Moggi, N; Moon, C S; Moore, R; Morello, M; Movilla Fernandez, P; Mülmenstädt, J; Mukherjee, A; Muller, Th; Mumford, R; Murat, P; Mussini, M; Nachtman, J; Nagai, Y; Nagano, A; Naganoma, J; Nakamura, K; Nakano, I; Napier, A; Necula, V; Neu, C; Neubauer, M S; Nielsen, J; Nodulman, L; Norman, M; Norniella, O; Nurse, E; Oh, S H; Oh, Y D; Oksuzian, I; Okusawa, T; Oldeman, R; Orava, R; Osterberg, K; Pagan Griso, S; Pagliarone, C; Palencia, E; Papadimitriou, V; Papaikonomou, A; Paramonov, A A; Parks, B; Pashapour, S; Patrick, J; Pauletta, G; Paulini, M; Paus, C; Pellett, D E; Penzo, A; Phillips, T J; Piacentino, G; Piedra, J; Pinera, L; Pitts, K; Plager, C; Pondrom, L; Portell, X; Poukhov, O; Pounder, N; Prakoshyn, F; Pronko, A; Proudfoot, J; Ptohos, F; Punzi, G; Pursley, J; Rademacker, J; Rahaman, A; Ramakrishnan, V; Ranjan, N; Redondo, I; Reisert, B; Rekovic, V; Renton, P; Rescigno, M; Richter, S; Rimondi, F; Ristori, L; Robson, A; Rodrigo, T; Rogers, E; Rolli, S; Roser, R; Rossi, M; Rossin, R; Roy, P; Ruiz, A; Russ, J; Rusu, V; Saarikko, H; Safonov, A; Sakumoto, W K; Salamanna, G; Saltó, O; Santi, L; Sarkar, S; Sartori, L; Sato, K; Savoy-Navarro, A; Scheidle, T; Schlabach, P; Schmidt, E E; Schmidt, M A; Schmidt, M P; Schmitt, M; Schwarz, T; Scodellaro, L; Scott, A L; Scribano, A; Scuri, F; Sedov, A; Seidel, S; Seiya, Y; Semenov, A; Sexton-Kennedy, L; Sfyria, A; Shalhout, S Z; Shapiro, M D; Shears, T; Shepard, P F; Sherman, D; Shimojima, M; Shochet, M; Shon, Y; Shreyber, I; Sidoti, A; Sinervo, P; Sisakyan, A; Slaughter, A J; Slaunwhite, J; Sliwa, K; Smith, J R; Snider, F D; Snihur, R; Soderberg, M; Soha, A; Somalwar, S; Sorin, V; Spalding, J; Spinella, F; Spreitzer, T; Squillacioti, P; Stanitzki, M; St Denis, R; Stelzer, B; Stelzer-Chilton, O; Stentz, D; Strologas, J; Stuart, D; Suh, J S; Sukhanov, A; Sun, H; Suslov, I; Suzuki, T; Taffard, A; Takashima, R; Takeuchi, Y; Tanaka, R; Tecchio, M; Teng, P K; Terashi, K; Thom, J; Thompson, A S; Thompson, G A; Thomson, E; Tipton, P; Tiwari, V; Tkaczyk, S; Toback, D; Tokar, S; Tollefson, K; Tomura, T; Tonelli, D; Torre, S; Torretta, D; Tourneur, S; Trischuk, W; Tu, Y; Turini, N; Ukegawa, F; Uozumi, S; Vallecorsa, S; van Remortel, N; Varganov, A; Vataga, E; Vázquez, F; Velev, G; Vellidis, C; Veszpremi, V; Vidal, M; Vidal, R; Vila, I; Vilar, R; Vine, T; Vogel, M; Volobouev, I; Volpi, G; Würthwein, F; Wagner, P; Wagner, R G; Wagner, R L; Wagner-Kuhr, J; Wagner, W; Wakisaka, T; Wallny, R; Wang, S M; Warburton, A; Waters, D; Weinberger, M; Wester, W C; Whitehouse, B; Whiteson, D; Wicklund, A B; Wicklund, E; Williams, G; Williams, H H; Wilson, P; Winer, B L; Wittich, P; Wolbers, S; Wolfe, C; Wright, T; Wu, X; Wynne, S M; Yagil, A; Yamamoto, K; Yamaoka, J; Yamashita, T; Yang, C; Yang, U K; Yang, Y C; Yao, W M; Yeh, G P; Yoh, J; Yorita, K; Yoshida, T; Yu, G B; Yu, I; Yu, S S; Yun, J C; Zanello, L; Zanetti, A; Zaw, I; Zhang, X; Zheng, Y; Zucchelli, S

    2008-03-14

    We have performed a search for B(s)(0) --> micro(+) micro(-) and B(0) --> micro(+) micro(-) decays in pp collisions at square root s = 1.96 TeV using 2 fb(-1) of integrated luminosity collected by the CDF II detector at the Fermilab Tevatron Collider. The observed number of B(s)(0) and B0 candidates is consistent with background expectations. The resulting upper limits on the branching fractions are B(B(s)0) --> micro(+) micro(-)) <5.8 x 10(-8) and B(B(0) --> micro(+) micro(-))<1.8 x 10(-8) at 95% C.L.

  13. A well-balanced diet combined or not with exercise induces fat mass loss without any decrease of bone mass despite bone micro-architecture alterations in obese rat.

    PubMed

    Gerbaix, Maude; Metz, Lore; Mac-Way, Fabrice; Lavet, Cédric; Guillet, Christelle; Walrand, Stéphane; Masgrau, Aurélie; Vico, Laurence; Courteix, Daniel

    2013-04-01

    The association of a well-balanced diet with exercise is a key strategy to treat obesity. However, weight loss is linked to an accelerated bone loss. Furthermore, exercise is known to induce beneficial effects on bone. We investigated the impact of a well-balanced isoenergetic reducing diet (WBR) and exercise on bone tissue in obese rats. Sixty male rats had previously been fed with a high fat/high sucrose diet (HF/HS) for 4months to induce obesity. Then, 4 regimens were initiated for 2months: HF/HS diet plus exercise (treadmill: 50min/day, 5days/week), WBR diet plus exercise, HF/HS diet plus inactivity and WBR diet plus inactivity. Body composition and total BMD were assessed using DXA and visceral fat mass was weighed. Tibia densitometry was assessed by Piximus. Bone histomorphometry was performed on the proximal metaphysis of tibia and on L2 vertebrae (L2). Trabecular micro-architectural parameters were measured on tibia and L2 by 3D microtomography. Plasma concentration of osteocalcin and CTX were measured. Both WBR diet and exercise had decreased global weight, global fat and visceral fat mass (p<0.05). The WBR diet alone failed to alter total and tibia bone mass and BMD. However, Tb.Th, bone volume density and degree of anisotropy of tibia were decreased by the WBR diet (p<0.05). Moreover, the WBR diet had involved a significant lower MS/BS and BFR/BS in L2 (p<0.05). Exercise had significantly improved BMD of the tibia possibly by inhibiting the bone resorption, as evidenced by no change in plasma osteocalcin levels, a decrease of CTX levels (p<0.005) and trabecular osteoclast number (p<0.05). In the present study a diet inducing weight and fat mass losses did not affected bone mass and BMD of obese rats despite alterations of their bone micro-architecture. The moderate intensity exercise performed had improved the tibia BMD of obese rats without any trabecular and cortical adaptation.

  14. Combined urea-thin layer chromatography and silver nitrate-thin layer chromatography for micro separation and determination of hard-to-detect branched chain fatty acids in natural lipids.

    PubMed

    Yan, Yuanyuan; Wang, Xingguo; Liu, Yijun; Xiang, Jingying; Wang, Xiaosan; Zhang, Huijun; Yao, Yunping; Liu, Ruijie; Zou, Xiaoqiang; Huang, Jianhua; Jin, Qingzhe

    2015-12-18

    A simple, fast and efficient procedure was developed for micro separation and enrichment of branched chain fatty acids (BCFA) from natural products using successive thin layer chromatography (TLC) technique coupling novel urea-TLC with AgNO3-TLC, which rely on the formation of urea adduction and AgNO3 bonding in methanol. These natural lipids contain a significant amount of straight chain fatty acids (FA). Fresh and fast urea-TLC and AgNO3-TLC plate making techniques were developed with more even coating and less coating material contamination before being utilized for separation. Goat milk fat was used as a model. Various experimental parameters that affect urea-TLC and AgNO3-TLC separation of BCFA were investigated and optimized, including coating of urea, concentration of original oil sample, mobile phase and sample application format. High efficiency of removal of straight chain FA was achieved with a low amount of sample in an easy and fast way. A total BCFA mix with much higher purity than previous studies was successfully achieved. The developed method has also been applied for the concentration and analysis of BCFA in cow milk fat and Anchovy oil. PMID:26614174

  15. Combined urea-thin layer chromatography and silver nitrate-thin layer chromatography for micro separation and determination of hard-to-detect branched chain fatty acids in natural lipids.

    PubMed

    Yan, Yuanyuan; Wang, Xingguo; Liu, Yijun; Xiang, Jingying; Wang, Xiaosan; Zhang, Huijun; Yao, Yunping; Liu, Ruijie; Zou, Xiaoqiang; Huang, Jianhua; Jin, Qingzhe

    2015-12-18

    A simple, fast and efficient procedure was developed for micro separation and enrichment of branched chain fatty acids (BCFA) from natural products using successive thin layer chromatography (TLC) technique coupling novel urea-TLC with AgNO3-TLC, which rely on the formation of urea adduction and AgNO3 bonding in methanol. These natural lipids contain a significant amount of straight chain fatty acids (FA). Fresh and fast urea-TLC and AgNO3-TLC plate making techniques were developed with more even coating and less coating material contamination before being utilized for separation. Goat milk fat was used as a model. Various experimental parameters that affect urea-TLC and AgNO3-TLC separation of BCFA were investigated and optimized, including coating of urea, concentration of original oil sample, mobile phase and sample application format. High efficiency of removal of straight chain FA was achieved with a low amount of sample in an easy and fast way. A total BCFA mix with much higher purity than previous studies was successfully achieved. The developed method has also been applied for the concentration and analysis of BCFA in cow milk fat and Anchovy oil.

  16. Liquid-liquid extraction of uranium(VI) with Aliquat® 336 from HCl media in microfluidic devices: Combination of micro-unit operations and online ICP-MS determination.

    PubMed

    Hellé, Gwendolyne; Mariet, Clarisse; Cote, Gérard

    2015-07-01

    The analysis of radionuclides is carried out according to operating protocols which include a series of chemical operations such as separation/purification steps and therefore is usually time-consuming, complex and difficult to put in place in a hostile environment (gloves box). In the present work, the liquid-liquid extraction of uranium in HCl media by Aliquat® 336 was performed in microsystem to demonstrate the potential of miniaturization in radiochemistry compared to classical protocols (decrease in volumes, analysis time, radiations received and feasibility of automation). Through the investigation of the influence of different parameters (flow rates, length of the microchannel, specific interfacial area), it was shown that the same performances of liquid-liquid extraction can be obtained in microsystem and in batch. Then, the coupling of different micro-unit operations for continuous process was performed to highlight the advantages of the miniaturized analytical techniques. The online ICP-MS determination of uranium(VI) was successfully coupled with the stripping of the latter from pre-loaded organic phases in microsystem, which constitutes a proof of concept and a first step towards a global analytical process with continuous flow. PMID:25882417

  17. Laser surface micro-/nano-structuring by a simple transportable micro-sphere lens array

    NASA Astrophysics Data System (ADS)

    Sedao, Xxx; Derrien, Thibault J.-Y.; Romer, Gert-willem R. B. E.; Pathiraj, Belavendram; Huis in `t Veld, Albertus J.

    2012-11-01

    A micro-sphere array optic was employed for laser surface micro-structuring. This array optic consists of a hexagonally close-packed monolayer of silica micro-spheres. It was organized through a self-assembly process and held together on a glass support, without using any adhesives. The array assembly was then reversed, placed in direct contact with the substrate and exposed to 515 nm, 6.7 ps laser pulses. During the exposure, the silica spheres act as micro-lenses, which enhance the near-field light intensity underneath them. As the spheres are confined in the space between the substrate and glass support, they are not ejected during laser machining. Using this type of direct write laser machining, a large number of identical features (nano-holes) can be produced in parallel simultaneously. The holes drilled are a few hundred nanometres in diameter and the depth depends on the number of laser pulses applied. The impact of laser machining on the micro-spheres was also studied. The micro-spheres were contaminated or partially damaged after micro-structuring. Combination of a moderate laser pulse energy and multiple shots was found to ensure a good surface structuring quality and minimum damage to the spherical particles.

  18. Proteomic analysis of cellular soluble proteins from human bronchial smooth muscle cells by combining nondenaturing micro 2DE and quantitative LC-MS/MS. 1. Preparation of more than 4000 native protein maps.

    PubMed

    Jin, Ya; Zhang, Jun; Yuan, Qi; Manabe, Takashi; Tan, Wen

    2015-08-01

    Soluble proteins of human bronchial smooth muscle cells (HBSMC) were separated by nondenaturing micro 2DE and a 30 mm × 40 mm area of the CBB-stained slab gel (1.0 mm thick) was cut into 1.1 mm × 1.1 mm squares, then the proteins in the 972 gel pieces (squares) were applied to quantitative LC-MS/MS. Grid-cutting of the gel was employed to; (i) ensure the total analysis of the proteins in the area, (ii) standardize the conditions of analysis by LC-MS/MS, (iii) reconstruct the protein distribution patterns from the quantity data [1]. Totally 4323 proteins were identified in successfully analyzed 967 squares and the quantity distribution of each was reconstructed as a color density pattern (a native protein map). The quantity of the proteins distributed from 3.6% to 1 × 10(-5) % of the total protein quantity in the grid area. Each protein map was characterized by several features, including the position of quantity peak square, number of detected squares, and degree of concentration (focused or dispersed). About 4% of the proteins were detected in 100 or more squares, suggesting that they might be ubiquitous and interacting with other proteins. In contrast, many proteins showed more concentrated quantity distribution and the quantity peak positions of 565 proteins with a defined degree of concentration were summarized into a quantity peak map. These results for the first time visualized the distribution patterns of cellular proteins on a nondenaturing 2D gel.

  19. Laser based micro forming and assembly.

    SciTech Connect

    MacCallum, Danny O'Neill; Wong, Chung-Nin Channy; Knorovsky, Gerald Albert; Steyskal, Michele D.; Lehecka, Tom; Scherzinger, William Mark; Palmer, Jeremy Andrew

    2006-11-01

    It has been shown that thermal energy imparted to a metallic substrate by laser heating induces a transient temperature gradient through the thickness of the sample. In favorable conditions of laser fluence and absorptivity, the resulting inhomogeneous thermal strain leads to a measurable permanent deflection. This project established parameters for laser micro forming of thin materials that are relevant to MESA generation weapon system components and confirmed methods for producing micrometer displacements with repeatable bend direction and magnitude. Precise micro forming vectors were realized through computational finite element analysis (FEA) of laser-induced transient heating that indicated the optimal combination of laser heat input relative to the material being heated and its thermal mass. Precise laser micro forming was demonstrated in two practical manufacturing operations of importance to the DOE complex: micrometer gap adjustments of precious metal alloy contacts and forming of meso scale cones.

  20. [Surgical treatment of micro-ophthalmic syndromes].

    PubMed

    Pellerin, P; Mouriaux, F; Dhellemmes-Defoort, S; Guilbert, F

    1997-10-01

    The complex embryology of the oculo-orbito-palpebral region is responsible for a number of heterogeneous clinicopathological situations, associating variable proportions of the three components of the malformation: micro-anophthalmia, microblepharism, micro-orbitism. Application of the double principle of skin expansion for the eyelids and distraction of the callus for the orbit, as early as possible (first year of life), is possible by means of a device which consists of a combination of an intraorbital expansion balloon, an antireflux valve to avoid effective pressure losses in the balloon, and an injection site for progressive filling of the expansion balloon. The response to these treatments is excellent for cases of simple microphthalmia and micro-orbitism; in complex craniofacial malformations, it generally only partially resolves the problem, but provides a precious complement to the quality of the final repair.

  1. MicroRNA-mediated somatic cell reprogramming.

    PubMed

    Kuo, Chih-Hao; Ying, Shao-Yao

    2013-02-01

    Since the first report of induced pluripotent stem cells (iPSCs) using somatic cell nuclear transfer (SCNT), much focus has been placed on iPSCs due to their great therapeutic potential for diseases such as abnormal development, degenerative disorders, and even cancers. Subsequently, Takahashi and Yamanaka took a novel approach by using four defined transcription factors to generate iPSCs in mice and human fibroblast cells. Scientists have since been trying to refine or develop better approaches to reprogramming, either by using different combinations of transcription factors or delivery methods. However, recent reports showed that the microRNA expression pattern plays a crucial role in somatic cell reprogramming and ectopic introduction of embryonic stem cell-specific microRNAs revert cells back to an ESC-like state, although, the exact mechanism underlying this effect remains unclear. This review describes recent work that has focused on microRNA-mediated approaches to somatic cell reprogramming as well as some of the pros and cons to these approaches and a possible mechanism of action. Based on the pivotal role of microRNAs in embryogenesis and somatic cell reprogramming, studies in this area must continue in order to gain a better understanding of the role of microRNAs in stem cells regulation and activity. PMID:22961769

  2. Micro-Expression Recognition Using Color Spaces.

    PubMed

    Wang, Su-Jing; Yan, Wen-Jing; Li, Xiaobai; Zhao, Guoying; Zhou, Chun-Guang; Fu, Xiaolan; Yang, Minghao; Tao, Jianhua

    2015-12-01

    Micro-expressions are brief involuntary facial expressions that reveal genuine emotions and, thus, help detect lies. Because of their many promising applications, they have attracted the attention of researchers from various fields. Recent research reveals that two perceptual color spaces (CIELab and CIELuv) provide useful information for expression recognition. This paper is an extended version of our International Conference on Pattern Recognition paper, in which we propose a novel color space model, tensor independent color space (TICS), to help recognize micro-expressions. In this paper, we further show that CIELab and CIELuv are also helpful in recognizing micro-expressions, and we indicate why these three color spaces achieve better performance. A micro-expression color video clip is treated as a fourth-order tensor, i.e., a four-dimension array. The first two dimensions are the spatial information, the third is the temporal information, and the fourth is the color information. We transform the fourth dimension from RGB into TICS, in which the color components are as independent as possible. The combination of dynamic texture and independent color components achieves a higher accuracy than does that of RGB. In addition, we define a set of regions of interests (ROIs) based on the facial action coding system and calculated the dynamic texture histograms for each ROI. Experiments are conducted on two micro-expression databases, CASME and CASME 2, and the results show that the performances for TICS, CIELab, and CIELuv are better than those for RGB or gray. PMID:26540689

  3. Micro heat barrier

    DOEpatents

    Marshall, Albert C.; Kravitz, Stanley H.; Tigges, Chris P.; Vawter, Gregory A.

    2003-08-12

    A highly effective, micron-scale micro heat barrier structure and process for manufacturing a micro heat barrier based on semiconductor and/or MEMS fabrication techniques. The micro heat barrier has an array of non-metallic, freestanding microsupports with a height less than 100 microns, attached to a substrate. An infrared reflective membrane (e.g., 1 micron gold) can be supported by the array of microsupports to provide radiation shielding. The micro heat barrier can be evacuated to eliminate gas phase heat conduction and convection. Semi-isotropic, reactive ion plasma etching can be used to create a microspike having a cusp-like shape with a sharp, pointed tip (<0.1 micron), to minimize the tip's contact area. A heat source can be placed directly on the microspikes. The micro heat barrier can have an apparent thermal conductivity in the range of 10.sup.-6 to 10.sup.-7 W/m-K. Multiple layers of reflective membranes can be used to increase thermal resistance.

  4. Silicon micro-mold

    DOEpatents

    Morales, Alfredo M.

    2006-10-24

    The present invention describes a method for rapidly fabricating a robust 3-dimensional silicon-mold for use in preparing complex metal micro-components. The process begins by depositing a conductive metal layer onto one surface of a silicon wafer. A thin photoresist and a standard lithographic mask are then used to transfer a trace image pattern onto the opposite surface of the wafer by exposing and developing the resist. The exposed portion of the silicon substrate is anisotropically etched through the wafer thickness down to conductive metal layer to provide an etched pattern consisting of a series of rectilinear channels and recesses in the silicon which serve as the silicon micro-mold. Microcomponents are prepared with this mold by first filling the mold channels and recesses with a metal deposit, typically by electroplating, and then removing the silicon micro-mold by chemical etching.

  5. Micro-Organ Devices

    NASA Technical Reports Server (NTRS)

    Gonda, Steven R.; Leslie, Julia; Chang, Robert C.; Starly, Binil; Sun, Wei; Culbertson, Christopher; Holtorf, Heidi

    2009-01-01

    Micro-organ devices (MODs) are being developed to satisfy an emerging need for small, lightweight, reproducible, biological-experimentati on apparatuses that are amenable to automated operation and that imp ose minimal demands for resources (principally, power and fluids). I n simplest terms, a MOD is a microfluidic device containing a variety of microstructures and assemblies of cells, all designed to mimic a complex in vivo microenvironment by replicating one or more in vivo micro-organ structures, the architectures and composition of the extr acellular matrices in the organs of interest, and the in vivo fluid flows. In addition to microscopic flow channels, a MOD contains one or more micro-organ wells containing cells residing in microscopic e xtracellular matrices and/or scaffolds, the shapes and compositions o f which enable replication of the corresponding in vivo cell assembl ies and flows.

  6. Monolithic MACS micro resonators

    NASA Astrophysics Data System (ADS)

    Lehmann-Horn, J. A.; Jacquinot, J.-F.; Ginefri, J. C.; Bonhomme, C.; Sakellariou, D.

    2016-10-01

    Magic Angle Coil Spinning (MACS) aids improving the intrinsically low NMR sensitivity of heterogeneous microscopic samples. We report on the design and testing of a new type of monolithic 2D MACS resonators to overcome known limitations of conventional micro coils. The resonators' conductors were printed on dielectric substrate and tuned without utilizing lumped element capacitors. Self-resonance conditions have been computed by a hybrid FEM-MoM technique. Preliminary results reported here indicate robust mechanical stability, reduced eddy currents heating and negligible susceptibility effects. The gain in B1 /√{ P } is in agreement with the NMR sensitivity enhancement according to the principle of reciprocity. A sensitivity enhancement larger than 3 has been achieved in a monolithic micro resonator inside a standard 4 mm rotor at 500 MHz. These 2D resonators could offer higher performance micro-detection and ease of use of heterogeneous microscopic substances such as biomedical samples, microscopic specimens and thin film materials.

  7. Micro-machined resonator

    DOEpatents

    Godshall, Ned A.; Koehler, Dale R.; Liang, Alan Y.; Smith, Bradley K.

    1993-01-01

    A micro-machined resonator, typically quartz, with upper and lower micro-machinable support members, or covers, having etched wells which may be lined with conductive electrode material, between the support members is a quartz resonator having an energy trapping quartz mesa capacitively coupled to the electrode through a diaphragm; the quartz resonator is supported by either micro-machined cantilever springs or by thin layers extending over the surfaces of the support. If the diaphragm is rigid, clock applications are available, and if the diaphragm is resilient, then transducer applications can be achieved. Either the thin support layers or the conductive electrode material can be integral with the diaphragm. In any event, the covers are bonded to form a hermetic seal and the interior volume may be filled with a gas or may be evacuated. In addition, one or both of the covers may include oscillator and interface circuitry for the resonator.

  8. Micro-machining.

    PubMed

    Brinksmeier, Ekkard; Preuss, Werner

    2012-08-28

    Manipulating bulk material at the atomic level is considered to be the domain of physics, chemistry and nanotechnology. However, precision engineering, especially micro-machining, has become a powerful tool for controlling the surface properties and sub-surface integrity of the optical, electronic and mechanical functional parts in a regime where continuum mechanics is left behind and the quantum nature of matter comes into play. The surprising subtlety of micro-machining results from the extraordinary precision of tools, machines and controls expanding into the nanometre range-a hundred times more precise than the wavelength of light. In this paper, we will outline the development of precision engineering, highlight modern achievements of ultra-precision machining and discuss the necessity of a deeper physical understanding of micro-machining.

  9. Monolithic MACS micro resonators.

    PubMed

    Lehmann-Horn, J A; Jacquinot, J-F; Ginefri, J C; Bonhomme, C; Sakellariou, D

    2016-10-01

    Magic Angle Coil Spinning (MACS) aids improving the intrinsically low NMR sensitivity of heterogeneous microscopic samples. We report on the design and testing of a new type of monolithic 2D MACS resonators to overcome known limitations of conventional micro coils. The resonators' conductors were printed on dielectric substrate and tuned without utilizing lumped element capacitors. Self-resonance conditions have been computed by a hybrid FEM-MoM technique. Preliminary results reported here indicate robust mechanical stability, reduced eddy currents heating and negligible susceptibility effects. The gain in B1/P is in agreement with the NMR sensitivity enhancement according to the principle of reciprocity. A sensitivity enhancement larger than 3 has been achieved in a monolithic micro resonator inside a standard 4mm rotor at 500MHz. These 2D resonators could offer higher performance micro-detection and ease of use of heterogeneous microscopic substances such as biomedical samples, microscopic specimens and thin film materials. PMID:27544845

  10. Micro-machined resonator

    DOEpatents

    Godshall, N.A.; Koehler, D.R.; Liang, A.Y.; Smith, B.K.

    1993-03-30

    A micro-machined resonator, typically quartz, with upper and lower micro-machinable support members, or covers, having etched wells which may be lined with conductive electrode material, between the support members is a quartz resonator having an energy trapping quartz mesa capacitively coupled to the electrode through a diaphragm; the quartz resonator is supported by either micro-machined cantilever springs or by thin layers extending over the surfaces of the support. If the diaphragm is rigid, clock applications are available, and if the diaphragm is resilient, then transducer applications can be achieved. Either the thin support layers or the conductive electrode material can be integral with the diaphragm. In any event, the covers are bonded to form a hermetic seal and the interior volume may be filled with a gas or may be evacuated. In addition, one or both of the covers may include oscillator and interface circuitry for the resonator.

  11. Method of fabricating a micro machine

    DOEpatents

    Stalford, Harold L

    2014-11-11

    A micro machine may be in or less than the micrometer domain. The micro machine may include a micro actuator and a micro shaft coupled to the micro actuator. The micro shaft is operable to be driven by the micro actuator. A tool is coupled to the micro shaft and is operable to perform work in response to at least motion of the micro shaft.

  12. Structure of catalase determined by MicroED

    PubMed Central

    Nannenga, Brent L; Shi, Dan; Hattne, Johan; Reyes, Francis E; Gonen, Tamir

    2014-01-01

    MicroED is a recently developed method that uses electron diffraction for structure determination from very small three-dimensional crystals of biological material. Previously we used a series of still diffraction patterns to determine the structure of lysozyme at 2.9 Å resolution with MicroED (Shi et al., 2013). Here we present the structure of bovine liver catalase determined from a single crystal at 3.2 Å resolution by MicroED. The data were collected by continuous rotation of the sample under constant exposure and were processed and refined using standard programs for X-ray crystallography. The ability of MicroED to determine the structure of bovine liver catalase, a protein that has long resisted atomic analysis by traditional electron crystallography, demonstrates the potential of this method for structure determination. DOI: http://dx.doi.org/10.7554/eLife.03600.001 PMID:25303172

  13. Structure of catalase determined by MicroED.

    PubMed

    Nannenga, Brent L; Shi, Dan; Hattne, Johan; Reyes, Francis E; Gonen, Tamir

    2014-01-01

    MicroED is a recently developed method that uses electron diffraction for structure determination from very small three-dimensional crystals of biological material. Previously we used a series of still diffraction patterns to determine the structure of lysozyme at 2.9 Å resolution with MicroED (Shi et al., 2013). Here we present the structure of bovine liver catalase determined from a single crystal at 3.2 Å resolution by MicroED. The data were collected by continuous rotation of the sample under constant exposure and were processed and refined using standard programs for X-ray crystallography. The ability of MicroED to determine the structure of bovine liver catalase, a protein that has long resisted atomic analysis by traditional electron crystallography, demonstrates the potential of this method for structure determination. PMID:25303172

  14. Coherent Synchrotron-Based Micro-Imaging Employed for Studies of Micro-Gap Formation in Dental Implants

    NASA Astrophysics Data System (ADS)

    Rack, T.; Zabler, S.; Rack, A.; Stiller, M.; Riesemeier, H.; Cecilia, A.; Nelson, K.

    2011-09-01

    Biocompatible materials such as titanium are regularly applied in oral surgery. Titanium-based implants for the replacement of missing teeth demand a high mechanical precision in order to minimize micro-bacterial leakage, especially when two-piece concepts are used. Synchrotron-based hard x-ray radiography, unlike conventional laboratory radiography, allows high spatial resolution in combination with high contrast even when micro-sized features in such highly attenuating objects are visualized. Therefore, micro-gap formation at interfaces in two-piece dental implants with the sample under different mechanical loads can be studied. We show the existence of micro-gaps in implants with conical connections and study the mechanical behavior of the mating zone of conical implants during loading. The micro-gap is a potential source of implant failure, i.e., bacterial leakage, which can be a stimulus for an inflammatory process.

  15. Coherent Synchrotron-Based Micro-Imaging Employed for Studies of Micro-Gap Formation in Dental Implants

    SciTech Connect

    Rack, T.; Stiller, M.; Nelson, K.; Zabler, S.; Rack, A.; Riesemeier, H.; Cecilia, A.

    2011-09-09

    Biocompatible materials such as titanium are regularly applied in oral surgery. Titanium-based implants for the replacement of missing teeth demand a high mechanical precision in order to minimize micro-bacterial leakage, especially when two-piece concepts are used. Synchrotron-based hard x-ray radiography, unlike conventional laboratory radiography, allows high spatial resolution in combination with high contrast even when micro-sized features in such highly attenuating objects are visualized. Therefore, micro-gap formation at interfaces in two-piece dental implants with the sample under different mechanical loads can be studied. We show the existence of micro-gaps in implants with conical connections and study the mechanical behavior of the mating zone of conical implants during loading. The micro-gap is a potential source of implant failure, i.e., bacterial leakage, which can be a stimulus for an inflammatory process.

  16. Gas-surface interactions using accommodation coefficients for a dilute and a dense gas in a micro- or nanochannel: heat flux predictions using combined molecular dynamics and Monte Carlo techniques.

    PubMed

    Nedea, S V; van Steenhoven, A A; Markvoort, A J; Spijker, P; Giordano, D

    2014-05-01

    The influence of gas-surface interactions of a dilute gas confined between two parallel walls on the heat flux predictions is investigated using a combined Monte Carlo (MC) and molecular dynamics (MD) approach. The accommodation coefficients are computed from the temperature of incident and reflected molecules in molecular dynamics and used as effective coefficients in Maxwell-like boundary conditions in Monte Carlo simulations. Hydrophobic and hydrophilic wall interactions are studied, and the effect of the gas-surface interaction potential on the heat flux and other characteristic parameters like density and temperature is shown. The heat flux dependence on the accommodation coefficient is shown for different fluid-wall mass ratios. We find that the accommodation coefficient is increasing considerably when the mass ratio is decreased. An effective map of the heat flux depending on the accommodation coefficient is given and we show that MC heat flux predictions using Maxwell boundary conditions based on the accommodation coefficient give good results when compared to pure molecular dynamics heat predictions. The accommodation coefficients computed for a dilute gas for different gas-wall interaction parameters and mass ratios are transferred to compute the heat flux predictions for a dense gas. Comparison of the heat fluxes derived using explicit MD, MC with Maxwell-like boundary conditions based on the accommodation coefficients, and pure Maxwell boundary conditions are discussed. A map of the heat flux dependence on the accommodation coefficients for a dense gas, and the effective accommodation coefficients for different gas-wall interactions are given. In the end, this approach is applied to study the gas-surface interactions of argon and xenon molecules on a platinum surface. The derived accommodation coefficients are compared with values of experimental results. PMID:25353885

  17. Gas-surface interactions using accommodation coefficients for a dilute and a dense gas in a micro- or nanochannel: heat flux predictions using combined molecular dynamics and Monte Carlo techniques.

    PubMed

    Nedea, S V; van Steenhoven, A A; Markvoort, A J; Spijker, P; Giordano, D

    2014-05-01

    The influence of gas-surface interactions of a dilute gas confined between two parallel walls on the heat flux predictions is investigated using a combined Monte Carlo (MC) and molecular dynamics (MD) approach. The accommodation coefficients are computed from the temperature of incident and reflected molecules in molecular dynamics and used as effective coefficients in Maxwell-like boundary conditions in Monte Carlo simulations. Hydrophobic and hydrophilic wall interactions are studied, and the effect of the gas-surface interaction potential on the heat flux and other characteristic parameters like density and temperature is shown. The heat flux dependence on the accommodation coefficient is shown for different fluid-wall mass ratios. We find that the accommodation coefficient is increasing considerably when the mass ratio is decreased. An effective map of the heat flux depending on the accommodation coefficient is given and we show that MC heat flux predictions using Maxwell boundary conditions based on the accommodation coefficient give good results when compared to pure molecular dynamics heat predictions. The accommodation coefficients computed for a dilute gas for different gas-wall interaction parameters and mass ratios are transferred to compute the heat flux predictions for a dense gas. Comparison of the heat fluxes derived using explicit MD, MC with Maxwell-like boundary conditions based on the accommodation coefficients, and pure Maxwell boundary conditions are discussed. A map of the heat flux dependence on the accommodation coefficients for a dense gas, and the effective accommodation coefficients for different gas-wall interactions are given. In the end, this approach is applied to study the gas-surface interactions of argon and xenon molecules on a platinum surface. The derived accommodation coefficients are compared with values of experimental results.

  18. Eye vision system using programmable micro-optics and micro-electronics

    NASA Astrophysics Data System (ADS)

    Riza, Nabeel A.; Amin, M. Junaid; Riza, Mehdi N.

    2014-02-01

    Proposed is a novel eye vision system that combines the use of advanced micro-optic and microelectronic technologies that includes programmable micro-optic devices, pico-projectors, Radio Frequency (RF) and optical wireless communication and control links, energy harvesting and storage devices and remote wireless energy transfer capabilities. This portable light weight system can measure eye refractive powers, optimize light conditions for the eye under test, conduct color-blindness tests, and implement eye strain relief and eye muscle exercises via time sequenced imaging. Described is the basic design of the proposed system and its first stage system experimental results for vision spherical lens refractive error correction.

  19. Micro-PROUST.

    ERIC Educational Resources Information Center

    Johnson, W. Lewis; Soloway, Elliot

    This detailed description of a microcomputer version of PROUST (Program Understander for Students), a knowledge-based system that finds nonsyntactic bugs in Pascal programs written by novice programmers, presents the inner workings of Micro-PROUST, which was written in Golden LISP for the IBM-PC (512K). The contents include: (1) a reprint of an…

  20. Micro acoustic spectrum analyzer

    DOEpatents

    Schubert, W. Kent; Butler, Michael A.; Adkins, Douglas R.; Anderson, Larry F.

    2004-11-23

    A micro acoustic spectrum analyzer for determining the frequency components of a fluctuating sound signal comprises a microphone to pick up the fluctuating sound signal and produce an alternating current electrical signal; at least one microfabricated resonator, each resonator having a different resonant frequency, that vibrate in response to the alternating current electrical signal; and at least one detector to detect the vibration of the microfabricated resonators. The micro acoustic spectrum analyzer can further comprise a mixer to mix a reference signal with the alternating current electrical signal from the microphone to shift the frequency spectrum to a frequency range that is a better matched to the resonant frequencies of the microfabricated resonators. The micro acoustic spectrum analyzer can be designed specifically for portability, size, cost, accuracy, speed, power requirements, and use in a harsh environment. The micro acoustic spectrum analyzer is particularly suited for applications where size, accessibility, and power requirements are limited, such as the monitoring of industrial equipment and processes, detection of security intrusions, or evaluation of military threats.

  1. The Micro-Shop.

    ERIC Educational Resources Information Center

    Steele, Barbara

    1992-01-01

    To reduce teacher isolation and encourage sharing of expertise, schools should consider brief workshops or 15-minute "micro-shops" on various topics ranging from making electrical circuit boards to setting up a salt-water aquarium. This article and accompanying sidebar discuss benefits and set-up strategies. (MLH)

  2. SUMC reconfigurable micro-assembler

    NASA Technical Reports Server (NTRS)

    Edwards, A. J.

    1973-01-01

    The development of a reconfigurable micro-assembler to provide the micro-programmer the capability to specify micro-instructions in concise, meaningful terms is discussed. The implementation plan for the development of the micro-assembler was predicted on the existing capabilities of the SUMC Reconfigurable Assembler. Utilizing the reconfigurable assembler as a base, new directives and existing directive modifications were implemented to provide the micro-assembly as a new capability of the reconfigurable assembler. The micro-assembler language allows the specification of all micro-instruction control field settings in one concise assembler source statement. The language appears very similar to a conventional machine instruction assembler language. The machine instruction assembler language has the characteristic of one operation specification per statement whereas, the micro-instruction assembler language allows multiple operations to be designated per statement.

  3. Miniature modified Faraday cup for micro electron beams

    DOEpatents

    Teruya, Alan T.; Elmer, John W.; Palmer, Todd A.; Walton, Chris C.

    2008-05-27

    A micro beam Faraday cup assembly includes a refractory metal layer with an odd number of thin, radially positioned traces in this refractory metal layer. Some of the radially positioned traces are located at the edge of the micro modified Faraday cup body and some of the radially positioned traces are located in the central portion of the micro modified Faraday cup body. Each set of traces is connected to a separate data acquisition channel to form multiple independent diagnostic networks. The data obtained from the two diagnostic networks are combined and inputted into a computed tomography algorithm to reconstruct the beam shape, size, and power density distribution.

  4. Rotary Apparatus Concentrates And Separates Micro-Organisms

    NASA Technical Reports Server (NTRS)

    Noever, David A.

    1992-01-01

    Apparatus concentrates and separates swimming micro-organisms of different species into concentric rings in fluid. Fluid containing high concentration of desired species removed by use of small scoop placed into fluid at radius of one of rings formed by that species. Micro-organisms concentrated into concentric rings by combined dynamic effects of upward and horizontal components of swimming, rotation of dish, gravitation, and viscosity.

  5. Breakthrough: micro-electronic photovoltaics

    SciTech Connect

    Okandan, Murat; Gupta, Vipin

    2012-04-23

    Sandia developed tiny glitter-sized photovoltaic (PV) cells that could revolutionize solar energy collection. The crystalline silicon micro-PV cells will be cheaper and have greater efficiencies than current PV collectors. Micro-PV cells require relatively little material to form well-controlled, highly efficient devices. Cell fabrication uses common microelectric and micro-electromechanical systems (MEMS) techniques.

  6. Breakthrough: micro-electronic photovoltaics

    ScienceCinema

    Okandan, Murat; Gupta, Vipin

    2016-07-12

    Sandia developed tiny glitter-sized photovoltaic (PV) cells that could revolutionize solar energy collection. The crystalline silicon micro-PV cells will be cheaper and have greater efficiencies than current PV collectors. Micro-PV cells require relatively little material to form well-controlled, highly efficient devices. Cell fabrication uses common microelectric and micro-electromechanical systems (MEMS) techniques.

  7. Methods and systems for micro transmissions

    DOEpatents

    Stalford, Harold L

    2014-12-23

    Methods and systems for micro transmissions for a micro machine may comprise an input shaft assembly coupled to a micro actuator, an output shaft assembly coupled to a micro shaft, and one or more power conversion elements operable to convert a first type of movement from the micro actuator into a second, disparate type of movement for the micro shaft.

  8. Methods and systems for micro bearings

    DOEpatents

    Stalford, Harold L

    2015-01-27

    A micro drive assembly may comprise a substrate, a micro shaft oriented in-plane with the substrate and at least one micro bearing to support rotation of the micro shaft. The micro shaft and micro bearing may be in or less than the micrometer domain.

  9. Methods and systems for micro bearings

    DOEpatents

    Stalford, Harold L.

    2012-10-09

    A micro drive assembly may comprise a substrate, a micro shall oriented in-plane with the substrate and at least one micro bearing to support rotation of the micro shaft. The micro shaft and micro bearing may be in or less than the micrometer domain.

  10. Micro pulse laser radar

    NASA Technical Reports Server (NTRS)

    Spinhirne, James D. (Inventor)

    1993-01-01

    An eye safe, compact, solid state lidar for profiling atmospheric cloud and aerosol scattering is disclosed. The transmitter of the micro pulse lidar is a diode pumped micro-J pulse energy, high repetition rate Nd:YLF laser. Eye safety is obtained through beam expansion. The receiver employs a photon counting solid state Geiger mode avalanche photodiode detector. Data acquisition is by a single card multichannel scaler. Daytime background induced quantum noise is controlled by a narrow receiver field-of-view and a narrow bandwidth temperature controlled interference filter. Dynamic range of the signal is limited to optical geometric signal compression. Signal simulations and initial atmospheric measurements indicate that micropulse lider systems are capable of detecting and profiling all significant cloud and aerosol scattering through the troposphere and into the stratosphere. The intended applications are scientific studies and environmental monitoring which require full time, unattended measurements of the cloud and aerosol height structure.

  11. Micro pulse lidar

    SciTech Connect

    Spinhirne, J.D. )

    1993-01-01

    An eye safe, compact, solid state lidar for profiling atmospheric cloud and aerosol scattering has been demonstrated. The transmitter of the micro pulse lidar is a diode pumped [mu]J pulse energy, high repetition rate Nd:YLF laser. Eye safety is obtained through beam expansion. The receiver employs a photon counting solid state Geiger mode avalanche photodiode detector. Data acquisition is by a single card multichannel scaler. Daytime background induced quantum noise is controlled by a narrow receiver field-of-view (FOV) and a narrow bandwidth temperature controlled interference filter. Dynamic range of the signal is limited by optical geometric signal compression. Signal simulations and initial atmospheric measurements indicate that systems built on the micro pulse lidar concept are capable of detecting and profiling all significant cloud and aerosol scattering through the troposphere and into the stratosphere. The intended applications are scientific studies and environmental monitoring which require full time, unattended measurements of the cloud and aerosol height structure.

  12. Scanning micro-sclerometer

    DOEpatents

    Oliver, Warren C.; Blau, Peter J.

    1994-01-01

    A scanning micro-sclerometer measures changes in contact stiffness and correlates these changes to characteristics of a scratch. A known force is applied to a contact junction between two bodies and a technique employing an oscillating force is used to generate the contact stiffness between the two bodies. As the two bodies slide relative to each other, the contact stiffness changes. The change is measured to characterize the scratch.

  13. Micro coring apparatus

    NASA Technical Reports Server (NTRS)

    Collins, David; Brooks, Marshall; Chen, Paul; Dwelle, Paul; Fischer, Ben

    1989-01-01

    A micro-coring apparatus for lunar exploration applications, that is compatible with the other components of the Walking Mobile Platform, was designed. The primary purpose of core sampling is to gain an understanding of the geological composition and properties of the prescribed environment. This procedure has been used extensively for Earth studies and in limited applications during lunar explorations. The corer is described and analyzed for effectiveness.

  14. Scanning micro-sclerometer

    DOEpatents

    Oliver, W.C.; Blau, P.J.

    1994-11-01

    A scanning micro-sclerometer measures changes in contact stiffness and correlates these changes to characteristics of a scratch. A known force is applied to a contact junction between two bodies and a technique employing an oscillating force is used to generate the contact stiffness between the two bodies. As the two bodies slide relative to each other, the contact stiffness changes. The change is measured to characterize the scratch. 2 figs.

  15. Warburg Micro syndrome.

    PubMed

    Dursun, Fatma; Güven, Ayla; Morris-Rosendahl, Deborah

    2012-01-01

    Micro syndrome is an autosomal recessive disorder characterized by severe intellectual disability, microcephaly, congenital cataract, microcornea, microphthalmia, agenesis, or hypoplasia of the corpus callosum and hypogenitalism. We report an 11-month-old boy who was referred for assessment of micropenis and cryptorchidism. Sequence analysis of exon 8 of the RAB3GAP1 gene confirmed the presence of a splice donor mutation (748+1G>A) in the homozygous state.

  16. Capillary micro-switches

    NASA Astrophysics Data System (ADS)

    Steen, Paul; Matalanis, Claude; Hirsa, Amir; Cox, Christhopher

    2002-11-01

    A capillary surface is a liquid/liquid or liquid/gas interface whose shape is determined by surface tension. Capillary surfaces occur when the capillary length is large compared to the container scale, as happens for typical liquids against gas on the sub-millimeter scale on Earth and on the meter scale in the micro-gravity environment of space vehicles. Manipulating capillary surfaces has emerged as a leading strategy for moving liquids on the micro-scale [1]. Practitioners have yet to take advantage of capillary instability in their design of devices, though. We illustrate how the response diagram of a single switch (bi-stable device) can be constructed from that of two capillary elements, how that of a system of switches (a pair) can be built from that of a single switch and finally how understanding the response of the system guides us to observations of new behavior in the laboratory. Experiments on capillary surfaces use either a soap-film analog (10 centimeter scale) or a liquid/gas (millimeter scale) apparatus. Progress is reported on the application of an array of micro-switches to make a controllable adhesion device, with the aim of effecting droplet transport. 1. Cho, Fan, Moon and Kim, "Towards digital microfluidic circuits: creating, transporting, cutting and merging liquid droplets by electrowetting-based actuation." Proc. 15th IEEE Int'l Conf. on MEMS, January 2002.

  17. Micro-Inspector Spacecraft Testbed: Breadboard Subsystem Demonstrations

    NASA Astrophysics Data System (ADS)

    Mueller, Juergen; Goldberg, Hannah; Alkalai, Leon

    2007-01-01

    Micro-inspector is a 5-kg inspection platform designed to operate autonomously following operator up-linked command sequences around a host spacecraft to perform safety inspections, anomaly inspections, or imaging of large in-space assemblies as envisioned for future NASA exploration missions. Similarly, such an inspection platform may be adapted to military space missions. Micro-inspector relies on solar power and using celestial sensors for navigation, giving the system large flexibility in the missions and applications it may serve, including those beyond Earth orbit. Micro-Inspector, through its small size and low weight, poses minimal design impacts to the host. Its small size and weight also affords micro-inspector to be disposable, allowing multiple inspectors to be used by a single host for different inspection routines or as emergency back-up. Its low-pressure butane propulsion system combines safety and compactness through liquid propellant storage with an adequate performance of up to 30 m/s for inspection maneuvers around the host. Micro-inspector, since power limited through a body mounted solar array, thus avoiding the complexities of deployable structures, relies on many advanced, ultra-low power micro-technologies, such as a novel microvalve by VACCO Industries in its propulsion system, electrochromic surface modulating heat transfer from the spacecraft using no moving parts, low power dual processor and FPGA-based reconfigurable and SEU mitigating avionics, a low power RF telecom link based on the Mars Micro Transceiver, and micro attitude control sensors, such as commercial micro IMUs and a JPL developed micro sun sensor. Host safety is a key concern, and multiple safety features are employed by micro-inspector to prevent any accidental impact onto the host. Among these is an active, laser-based range-finding collision avoidance system, which constantly monitors the distance to the host and via the micro-inspector's control system maintains a safe

  18. Modeling and control for micro and nano manipulation

    NASA Astrophysics Data System (ADS)

    Wejinya, Uchechukwu C.

    handling and deposition of micro and nano entities such as carbon nanotubes (CNT), DNA, and for droplet control. The novel microfluidic end effector system with force sensing can significantly improve the success rate for handling/depositing micro/nano entities in the case of carbon nanotubes between micro electrodes. The design, calibration, and experimental implementation of the novel microfluidic end effector is carried out in this research. The experimental results show the success rate for carbon nanotube(s) deposition between micro electrodes can reach close to 80%. Furthermore, carbon nanotubes are of particular interest because they are good candidates for many electronics and sensing applications. The interests in using carbon nanotubes to manufacture electronics and sensors have increased in recent years because of the increase need for making electronics smaller, and their excellent electrical and mechanical properties. These potentials can be achieved if CNTs with semiconducting and metallic band structure can be successfully deposited and separated. The use of dielectrophoresis (DEP) has been established as a course towards the efficient deposition and separation of metallic carbon nanotubes from semiconducting carbon nanotubes. For this reason, this research presents a new mathematical model for dielectrophoresis and electrorotation of carbon nanotubes. Simulation results are presented in this research to validate the developed model. The combination of both the micro robotic manipulation system and the atomic force microscopy (AFM) based nano-robotic system will provide a powerful tool for micro and nano manipulation. Additional applications of this research are endless considering the rapid development of micro and nano technologies.

  19. Combining micro dry column chromatography and mass spectrometry

    NASA Technical Reports Server (NTRS)

    Bauman, A. J.

    1970-01-01

    Dry column chromatography principles applied in microscale produce technique to minimize time in preparing and analyzing colorless constituents of soluble mixtures. Glass pipette microcolumns filled with finely sieved adsorbents permit capillary attraction and separation in 3 to 15 minutes. Technique is adaptable to gas chromatography.

  20. Optical assembly of bio-hybrid micro-robots.

    PubMed

    Barroso, Álvaro; Landwerth, Shirin; Woerdemann, Mike; Alpmann, Christina; Buscher, Tim; Becker, Maike; Studer, Armido; Denz, Cornelia

    2015-04-01

    The combination of micro synthetic structures with bacterial flagella motors represents an actual trend for the construction of self-propelled micro-robots. The development of methods for fabrication of these bacteria-based robots is a first crucial step towards the realization of functional miniature and autonomous moving robots. We present a novel scheme based on optical trapping to fabricate living micro-robots. By using holographic optical tweezers that allow three-dimensional manipulation in real time, we are able to arrange the building blocks that constitute the micro-robot in a defined way. We demonstrate exemplarily that our method enables the controlled assembly of living micro-robots consisting of a rod-shaped prokaryotic bacterium and a single elongated zeolite L crystal, which are used as model of the biological and abiotic components, respectively. We present different proof-of-principle approaches for the site-selective attachment of the bacteria on the particle surface. The propulsion of the optically assembled micro-robot demonstrates the potential of the proposed method as a powerful strategy for the fabrication of bio-hybrid micro-robots.

  1. Bio-barcode gel assay for microRNA

    NASA Astrophysics Data System (ADS)

    Lee, Hyojin; Park, Jeong-Eun; Nam, Jwa-Min

    2014-02-01

    MicroRNA has been identified as a potential biomarker because expression level of microRNA is correlated with various cancers. Its detection at low concentrations would be highly beneficial for cancer diagnosis. Here, we develop a new type of a DNA-modified gold nanoparticle-based bio-barcode assay that uses a conventional gel electrophoresis platform and potassium cyanide chemistry and show this assay can detect microRNA at aM levels without enzymatic amplification. It is also shown that single-base-mismatched microRNA can be differentiated from perfectly matched microRNA and the multiplexed detection of various combinations of microRNA sequences is possible with this approach. Finally, differently expressed microRNA levels are selectively detected from cancer cells using the bio-barcode gel assay, and the results are compared with conventional polymerase chain reaction-based results. The method and results shown herein pave the way for practical use of a conventional gel electrophoresis for detecting biomolecules of interest even at aM level without polymerase chain reaction amplification.

  2. Optical assembly of bio-hybrid micro-robots.

    PubMed

    Barroso, Álvaro; Landwerth, Shirin; Woerdemann, Mike; Alpmann, Christina; Buscher, Tim; Becker, Maike; Studer, Armido; Denz, Cornelia

    2015-04-01

    The combination of micro synthetic structures with bacterial flagella motors represents an actual trend for the construction of self-propelled micro-robots. The development of methods for fabrication of these bacteria-based robots is a first crucial step towards the realization of functional miniature and autonomous moving robots. We present a novel scheme based on optical trapping to fabricate living micro-robots. By using holographic optical tweezers that allow three-dimensional manipulation in real time, we are able to arrange the building blocks that constitute the micro-robot in a defined way. We demonstrate exemplarily that our method enables the controlled assembly of living micro-robots consisting of a rod-shaped prokaryotic bacterium and a single elongated zeolite L crystal, which are used as model of the biological and abiotic components, respectively. We present different proof-of-principle approaches for the site-selective attachment of the bacteria on the particle surface. The propulsion of the optically assembled micro-robot demonstrates the potential of the proposed method as a powerful strategy for the fabrication of bio-hybrid micro-robots. PMID:25681045

  3. Combination Vaccines

    PubMed Central

    Skibinski, David AG; Baudner, Barbara C; Singh, Manmohan; O’Hagan, Derek T

    2011-01-01

    The combination of diphtheria, tetanus, and pertussis vaccines into a single product has been central to the protection of the pediatric population over the past 50 years. The addition of inactivated polio, Haemophilus influenzae, and hepatitis B vaccines into the combination has facilitated the introduction of these vaccines into recommended immunization schedules by reducing the number of injections required and has therefore increased immunization compliance. However, the development of these combinations encountered numerous challenges, including the reduced response to Haemophilus influenzae vaccine when given in combination; the need to consolidate the differences in the immunization schedule (hepatitis B); and the need to improve the safety profile of the diphtheria, tetanus, and pertussis combination. Here, we review these challenges and also discuss future prospects for combination vaccines. PMID:21572611

  4. Exploring cellular adhesion and differentiation in a micro-/nano-hybrid polymer scaffold.

    PubMed

    Cheng, Ke; Kisaalita, William S

    2010-01-01

    Polymer scaffolds play an important role in three dimensional (3-D) cell culture and tissue engineering. To best mimic the archiecture of natural extracellular matrix (ECM), a nano-fibrous and micro-porous combined (NFMP) scaffold was fabricated by combining phase separation and particulate leaching techniques. The NFMP scaffold possesses architectural features at two levels, including the micro-scale pores and nano-scale fibers. To evaluate the advantages of micro/nano combination, control scaffolds with only micro-pores or nano-fibers were fabricated. Cell grown in NFMP and control scaffolds were characterized with respect to morphology, proliferation rate, diffentiation and adhesion. The NFMP scaffold combined the advantages of micro- and nano-scale structures. The NFMP scaffold nano-fibers promoted neural differentiation and induced "3-D matrix adhesion", while the NFMP scaffold micro-pores facilitated cell infiltration. This study represents a systematic comparison of cellular activities on micro-only, nano-only and micro/nano combined scaffolds, and demonstrates the unique advantages of the later.

  5. Power combiner

    SciTech Connect

    Arnold, Mobius; Ives, Robert Lawrence

    2006-09-05

    A power combiner for the combining of symmetric and asymmetric traveling wave energy comprises a feed waveguide having an input port and a launching port, a reflector for reflecting launched wave energy, and a final waveguide for the collection and transport of launched wave energy. The power combiner has a launching port for symmetrical waves which comprises a cylindrical section coaxial to the feed waveguide, and a launching port for asymmetric waves which comprises a sawtooth rotated about a central axis.

  6. Recent progress in micro and nano-joining

    NASA Astrophysics Data System (ADS)

    Zhou, Y.; Hu, A.; Khan, M. I.; Wu, W.; Tam, B.; Yavuz, M.

    2009-05-01

    Micro and nano-joining has been identified as a key enabling technology in the construction of micromechanical and microelectronic devices. The current article reviews recent progress in micro and nano-joining. In particular, laser micro-welding (LMW) of crossed 316 LVM stainless steel (SS) wire was compared to conventional resistance micro-welding (RMW) and was successfully employed in welding a Pt-Ir /SS dissimilar combination. Welding of Au nanoparticles was realized using femtosecond laser irradiation and its application in the surface enhanced Raman spectroscopy was investigated. Brazing between carbon nanotube (CNT) bundles and Ni electrodes was attained in vacuum, resulting in the development of a novel CNT filament of incandescent lamps.

  7. Phenotypic MicroRNA Microarrays

    PubMed Central

    Kwon, Yong-Jun; Heo, Jin Yeong; Kim, Hi Chul; Kim, Jin Yeop; Liuzzi, Michel; Soloveva, Veronica

    2013-01-01

    Microarray technology has become a very popular approach in cases where multiple experiments need to be conducted repeatedly or done with a variety of samples. In our lab, we are applying our high density spots microarray approach to microscopy visualization of the effects of transiently introduced siRNA or cDNA on cellular morphology or phenotype. In this publication, we are discussing the possibility of using this micro-scale high throughput process to study the role of microRNAs in the biology of selected cellular models. After reverse-transfection of microRNAs and siRNA, the cellular phenotype generated by microRNAs regulated NF-κB expression comparably to the siRNA. The ability to print microRNA molecules for reverse transfection into cells is opening up the wide horizon for the phenotypic high content screening of microRNA libraries using cellular disease models.

  8. Electrochemical micro sensor

    DOEpatents

    Setter, Joseph R.; Maclay, G. Jordan

    1989-09-12

    A micro-amperometric electrochemical sensor for detecting the presence of a pre-determined species in a fluid material is disclosed. The sensor includes a smooth substrate having a thin coating of solid electrolytic material deposited thereon. The working and counter electrodes are deposited on the surface of the solid electrolytic material and adhere thereto. Electrical leads connect the working and counter electrodes to a potential source and an apparatus for measuring the change in an electrical signal caused by the electrochemical oxidation or reduction of the species. Alternatively, the sensor may be fabricated in a sandwich structure and also may be cylindrical, spherical or other shapes.

  9. Micro-fluidic interconnect

    DOEpatents

    Okandan, Murat; Galambos, Paul C.; Benavides, Gilbert L.; Hetherington, Dale L.

    2006-02-28

    An apparatus for simultaneously aligning and interconnecting microfluidic ports is presented. Such interconnections are required to utilize microfluidic devices fabricated in Micro-Electromechanical-Systems (MEMS) technologies, that have multiple fluidic access ports (e.g. 100 micron diameter) within a small footprint, (e.g. 3 mm.times.6 mm). Fanout of the small ports of a microfluidic device to a larger diameter (e.g. 500 microns) facilitates packaging and interconnection of the microfluidic device to printed wiring boards, electronics packages, fluidic manifolds etc.

  10. microRNA Therapeutics

    PubMed Central

    Broderick, JA; Zamore, PD

    2011-01-01

    MicroRNAs (miRNAs) provide new therapeutic targets for many diseases, while their myriad roles in development and cellular processes make them fascinating to study. We still do not fully understand the molecular mechanisms by which miRNAs regulate gene expression nor do we know the complete repertoire of mRNAs each miRNA regulates. However, recent progress in the development of effective strategies to block miRNAs suggests that anti-miRNA drugs may soon be used in the clinic. PMID:21525952

  11. MicroRNA expression profiles associated with pancreatic adenocarcinoma and ampullary adenocarcinoma.

    PubMed

    Schultz, Nicolai A; Werner, Jens; Willenbrock, Hanni; Roslind, Anne; Giese, Nathalia; Horn, Thomas; Wøjdemann, Morten; Johansen, Julia S

    2012-12-01

    MicroRNAs have potential as diagnostic cancer biomarkers. The aim of this study was (1) to define microRNA expression patterns in formalin-fixed parafin-embedded tissue from pancreatic ductal adenocarcinoma, ampullary adenocarcinoma, normal pancreas and chronic pancreatitis without using micro-dissection and (2) to discover new diagnostic microRNAs and combinations of microRNAs in cancer tissue. The expression of 664 microRNAs in tissue from 170 pancreatic adenocarcinomas and 107 ampullary adenocarcinomas were analyzed using a commercial microRNA assay. Results were compared with chronic pancreatitis, normal pancreas and duodenal adenocarcinoma. In all, 43 microRNAs had higher and 41 microRNAs reduced expression in pancreatic cancer compared with normal pancreas. In all, 32 microRNAs were differently expressed in pancreatic adenocarcinoma compared with chronic pancreatitis (17 higher; 15 reduced). Several of these microRNAs have not before been related to diagnosis of pancreatic cancer (eg, miR-492, miR-614, miR-622). MiR-614, miR-492, miR-622, miR-135b and miR-196 were most differently expressed. MicroRNA profiles of pancreatic and ampullary adenocarcinomas were correlated (0.990). MicroRNA expression profiles for pancreatic cancer described in the literature were consistent with our findings, and the microRNA profile for pancreatic adenocarcinoma (miR-196b-miR-217) was validated. We identified a more significant expression profile, the difference between miR-411 and miR-198 (P=2.06 × 10(-54)) and a diagnostic LASSO classifier using 19 microRNAs (sensitivity 98.5%; positive predictive value 97.8%; accuracy 97.0%). We also identified microRNA profiles to subclassify ampullary adenocarcinomas into pancreatobiliary or intestinal type. In conclusion, we found that combinations of two microRNAs could roughly separate neoplastic from non-neoplastic samples. A diagnostic 19 microRNA classifier was constructed which without micro-dissection could discriminate pancreatic

  12. Development of a 3D touch trigger probe using micro spherical stylus machining by micro-EDM for micro-CMM

    NASA Astrophysics Data System (ADS)

    Chu, Chih-Liang; Chen, Yi-Lin; Tai, Tzu-Yao; Liu, Yun-Hui; Chuang, Cheng-Hsin; Lu, Chin-Tu

    2011-12-01

    This study develops a low-cost three-dimensional touch trigger probe for micro-CMM using micro spherical stylus machining by micro-EDM. The tip ball of the stylus, with a diameter smaller than 100 µm, is made by a micro electro discharge machine with the method of wire electro discharge grinding (WEDG). The current study uses tungsten carbide (WC) as the material for the stylus. Experimental results show that, the tip ball roundness could amount to 2 µm. Since the tip ball is not easily observable by naked eyes, we designed a micro imaging system to observe the probing in real time. This system is created with modified commercial webcam and microscope. The general design of the touch trigger probe is combined the stylus and suspension structure. When the stylus touches workpiece, it can be determined the time of probe trigger by measuring the motion of suspension structure. The stylus machined by micro-EDM was very fragile and the stylus handle of the tip ball was very thin. Therefore, the stylus handle bends easily that would result in the large measurement error or stylus break when the stylus touched workpiece. In this study we designed a measuring probe using a small chuck and an electrical circuit to measure the probe trigger. When the stylus touches the workpiece, the parallel circuit will switch on immediately and pick up the voltage variation of the resistor. Because the transistor always turns ON, it can avoid the problems of excessive energy and electrical noise.

  13. microRNAs in Psoriasis.

    PubMed

    Hawkes, Jason E; Nguyen, Giang Huong; Fujita, Mayumi; Florell, Scott R; Callis Duffin, Kristina; Krueger, Gerald G; O'Connell, Ryan M

    2016-02-01

    Psoriasis is a chronic inflammatory skin condition resulting from a complex interplay among the immune system, keratinocytes, susceptibility genes, and environmental factors. However, the pathogenesis of psoriasis is not completely elucidated. microRNAs represent a promising class of small, noncoding RNA molecules that function to regulate gene expression. Although microRNA research in psoriasis and dermatology is still relatively new, evidence is rapidly accumulating for the role of microRNAs in the pathogenesis of psoriasis and other chronic inflammatory conditions. In this article, we present a comprehensive review of what is known about microRNAs and their role in the pathogenesis of psoriasis. PMID:26802234

  14. microRNAs in Psoriasis.

    PubMed

    Hawkes, Jason E; Nguyen, Giang Huong; Fujita, Mayumi; Florell, Scott R; Callis Duffin, Kristina; Krueger, Gerald G; O'Connell, Ryan M

    2016-02-01

    Psoriasis is a chronic inflammatory skin condition resulting from a complex interplay among the immune system, keratinocytes, susceptibility genes, and environmental factors. However, the pathogenesis of psoriasis is not completely elucidated. microRNAs represent a promising class of small, noncoding RNA molecules that function to regulate gene expression. Although microRNA research in psoriasis and dermatology is still relatively new, evidence is rapidly accumulating for the role of microRNAs in the pathogenesis of psoriasis and other chronic inflammatory conditions. In this article, we present a comprehensive review of what is known about microRNAs and their role in the pathogenesis of psoriasis.

  15. Combined acoustic and optical trapping

    PubMed Central

    Thalhammer, G.; Steiger, R.; Meinschad, M.; Hill, M.; Bernet, S.; Ritsch-Marte, M.

    2011-01-01

    Combining several methods for contact free micro-manipulation of small particles such as cells or micro-organisms provides the advantages of each method in a single setup. Optical tweezers, which employ focused laser beams, offer very precise and selective handling of single particles. On the other hand, acoustic trapping with wavelengths of about 1 mm allows the simultaneous trapping of many, comparatively large particles. With conventional approaches it is difficult to fully employ the strengths of each method due to the different experimental requirements. Here we present the combined optical and acoustic trapping of motile micro-organisms in a microfluidic environment, utilizing optical macro-tweezers, which offer a large field of view and working distance of several millimeters and therefore match the typical range of acoustic trapping. We characterize the acoustic trapping forces with the help of optically trapped particles and present several applications of the combined optical and acoustic trapping, such as manipulation of large (75 μm) particles and active particle sorting. PMID:22025990

  16. A micro-coupling for micro mechanical systems

    NASA Astrophysics Data System (ADS)

    Li, Wei; Zhou, Zhixiong; Zhang, Bi; Xiao, Yunya

    2016-05-01

    The error motions of micro mechanical systems, such as micro-spindles, increase with the increasing of the rotational speed, which not only decreases the rotational accuracy, but also promotes instability and limits the maximum operational speed. One effective way to deal with it is to use micro-flexible couplings between the drive and driven shafts so as to reduce error motions of the driven shaft. But the conventional couplings, such as diaphragm couplings, elastomeric couplings, bellows couplings, and grooved couplings, etc, cannot be directly used because of their large and complicated structures. This study presents a novel micro-coupling that consists of a flexible coupling and a shape memory alloy (SMA)-based clamp for micro mechanical systems. It is monolithic and can be directly machined from a shaft. The study performs design optimization and provides manufacturing considerations, including thermo-mechanical training of the SMA ring for the desired Two-Way-Shape-Memory effect (TWSMe). A prototype micro-coupling and a prototype micro-spindle using the proposed coupling are fabricated and tested. The testing results show that the prototype micro-coupling can bear a torque of above 5 N • mm and an axial force of 8.5 N and be fitted with an SMA ring for clamping action at room temperature (15 °C) and unclamping action below-5 °C. At the same time, the prototype micro-coupling can work at a rotational speed of above 200 kr/min with the application to a high-speed precision micro-spindle. Moreover, the radial runout error of the artifact, as a substitute for the micro-tool, is less than 3 μm while that of turbine shaft is above 7 μm. It can be concluded that the micro-coupling successfully accommodates misalignment errors of the prototype micro-spindle. This research proposes a micro-coupling which is featured with an SMA ring, and it is designed to clamp two shafts, and has smooth transmission, simple assembly, compact structure, zero-maintenance and

  17. Methods and systems for positioning micro elements

    DOEpatents

    Stalford, Harold L

    2015-04-28

    A micro device may comprise a substrate, a first micro structure coupled to the substrate, a second micro structure coupled to the substrate, and port configured to receive an input. The first micro structure is configured to move into engagement with the second micro structure in response to the input.

  18. Methods and systems for positioning micro elements

    DOEpatents

    Stalford; Harold L.

    2012-03-13

    A micro device may comprise a substrate, a first micro structure coupled to the substrate, a second micro structure coupled to the substrate, and port configured to receive an input. The first micro structure is configured to move into engagement with the second micro structure in response to the input.

  19. microRNAs as neuroregulators, biomarkers and therapeutic agents in neurodegenerative diseases.

    PubMed

    Basak, Indranil; Patil, Ketan S; Alves, Guido; Larsen, Jan Petter; Møller, Simon Geir

    2016-02-01

    The last decade has experienced the emergence of microRNAs as a key molecular tool for the diagnosis and prognosis of human diseases. Although the focus has mostly been on cancer, neurodegenerative diseases present an exciting, yet less explored, platform for microRNA research. Several studies have highlighted the significance of microRNAs in neurogenesis and neurodegeneration, and pre-clinical studies have shown the potential of microRNAs as biomarkers. Despite this, no bona fide microRNAs have been identified as true diagnostic or prognostic biomarkers for neurodegenerative disease. This is mainly due to the lack of precisely defined patient cohorts and the variability within and between individual cohorts. However, the discovery that microRNAs exist as stable molecules at detectable levels in body fluids has opened up new avenues for microRNAs as potential biomarker candidates. Furthermore, technological developments in microRNA biology have contributed to the possible design of microRNA-mediated disease intervention strategies. The combination of these advancements, with the availability of well-defined longitudinal patient cohort, promises to not only assist in developing invaluable diagnostic tools for clinicians, but also to increase our overall understanding of the underlying heterogeneity of neurodegenerative diseases. In this review, we present a comprehensive overview of the existing knowledge of microRNAs in neurodegeneration and provide a perspective of the applicability of microRNAs as a basis for future therapeutic intervention strategies.

  20. microRNAs as neuroregulators, biomarkers and therapeutic agents in neurodegenerative diseases.

    PubMed

    Basak, Indranil; Patil, Ketan S; Alves, Guido; Larsen, Jan Petter; Møller, Simon Geir

    2016-02-01

    The last decade has experienced the emergence of microRNAs as a key molecular tool for the diagnosis and prognosis of human diseases. Although the focus has mostly been on cancer, neurodegenerative diseases present an exciting, yet less explored, platform for microRNA research. Several studies have highlighted the significance of microRNAs in neurogenesis and neurodegeneration, and pre-clinical studies have shown the potential of microRNAs as biomarkers. Despite this, no bona fide microRNAs have been identified as true diagnostic or prognostic biomarkers for neurodegenerative disease. This is mainly due to the lack of precisely defined patient cohorts and the variability within and between individual cohorts. However, the discovery that microRNAs exist as stable molecules at detectable levels in body fluids has opened up new avenues for microRNAs as potential biomarker candidates. Furthermore, technological developments in microRNA biology have contributed to the possible design of microRNA-mediated disease intervention strategies. The combination of these advancements, with the availability of well-defined longitudinal patient cohort, promises to not only assist in developing invaluable diagnostic tools for clinicians, but also to increase our overall understanding of the underlying heterogeneity of neurodegenerative diseases. In this review, we present a comprehensive overview of the existing knowledge of microRNAs in neurodegeneration and provide a perspective of the applicability of microRNAs as a basis for future therapeutic intervention strategies. PMID:26608596

  1. A Micro-Ultrastable Oscillator (micro-US0) for Micro/Nano Sciencecraft

    NASA Technical Reports Server (NTRS)

    2003-01-01

    Syntonics LLC developed a prototype micro-Ultra Stable Oscillator (micro-USO) under a Space Base Technology Grant (NAGS-10395). Syntonics conducted the micro-USO Program in two phases. In Phase I, we developed a set of verified analytical models (including thermal, electrical, and control models) for a baseline USO, conducted a series of six technology studies, and built three approx.9OOg prototype units. These prototypes provided a tool for evaluating competing design topologies. In Phase II we prepared the conceptual design of a approx.100-15Og micro-USO.

  2. Micro rotary machine and methods for using same

    DOEpatents

    Stalford, Harold L.

    2012-04-17

    A micro rotary machine may include a micro actuator and a micro shaft coupled to the micro actuator. The micro shaft comprises a horizontal shaft and is operable to be rotated by the micro actuator. A micro tool is coupled to the micro shaft and is operable to perform work in response to motion of the micro shaft.

  3. Micro rotary machine and methods for using same

    SciTech Connect

    Stalford, Harold

    2015-01-13

    A micro rotary machine may include a micro actuator and a micro shaft coupled to the micro actuator. The micro shaft comprises a horizontal shaft and is operable to be rotated by the micro actuator. A micro tool is coupled to the micro shaft and is operable to perform work in response to motion of the micro shaft.

  4. MicroProbe Small Unmanned Aerial System

    NASA Technical Reports Server (NTRS)

    Bland, Geoffrey; Miles, Ted

    2012-01-01

    The MicroProbe unmanned aerial system (UAS) concept incorporates twin electric motors mounted on the vehicle wing, thus enabling an aerodynamically and environmentally clean nose area for atmospheric sensors. A payload bay is also incorporated in the fuselage to accommodate remote sensing instruments. A key feature of this concept is lightweight construction combined with low flying speeds to minimize kinetic energy and associated hazards, as well as maximizing spatial resolution. This type of aerial platform is needed for Earth science research and environmental monitoring. There were no vehicles of this type known to exist previously.

  5. Lead resistance in micro-organisms.

    PubMed

    Jarosławiecka, Anna; Piotrowska-Seget, Zofia

    2014-01-01

    Lead (Pb) is an element present in the environment that negatively affects all living organisms. To diminish its high toxicity, micro-organisms have developed several mechanisms that allow them to survive exposure to Pb(II). The main mechanisms of lead resistance involve adsorption by extracellular polysaccharides, cell exclusion, sequestration as insoluble phosphates, and ion efflux to the cell exterior. This review describes the various lead resistance mechanisms, and the regulation of their expression by lead binding regulatory proteins. Special attention is given to the Pbr system from Cupriavidus metallidurans CH34, which involves a unique mechanism combining efflux and lead precipitation.

  6. Micro-EDM for silicon microstructure fabrication

    NASA Astrophysics Data System (ADS)

    Song, Xiaozhong; Reynaerts, Dominiek; Meeusen, Wim; Van Brussel, Hendrik

    1999-03-01

    Currently, most silicon microstructures used in microstructures are produced by photolithographic methods. The reason for this is the well-developed etching technology, used in microelectronics, that has been transferred to the microsystem domain. But since the making of an arbitrary shape or angle on silicon mainly depends on the crystal orientation, some severe limits exist in the production of 3D structures. Electro-discharge machining (EDM) is basically a thermal process. During the EDM process material is removed by electric sparking. It is therefore completely different from etching. In this work, micro-EDM is introduce as a potential approach for solving the above mentioned drawbacks. First, this work presents several testing experiments with different process parameters to investigate the influence of the micro-EDM process on the silicon structure. Main emphasis is put on the surface roughness and on avoiding microcracks generated by the sparking process. It is found that microstructures with a sufficiently low surface roughness and with small microcracks can be produced. The remainder of the work concentrates on making small beam structures, which is a common structure in many microsensor designs. It is found that for a wafer thickness of 650 micrometers , the thinnest beam that can be produced is about 30 micrometers wide. This means that micro-EDM can offer an aspect ratio of 20 in combination with a god dimensional control.

  7. Micro-channel plate detector

    SciTech Connect

    Elam, Jeffrey W.; Lee, Seon W.; Wang, Hsien -Hau; Pellin, Michael J.; Byrum, Karen; Frisch, Henry J.

    2015-09-22

    A method and system for providing a micro-channel plate detector. An anodized aluminum oxide membrane is provided and includes a plurality of nanopores which have an Al coating and a thin layer of an emissive oxide material responsive to incident radiation, thereby providing a plurality of radiation sensitive channels for the micro-channel plate detector.

  8. Programming in Micro-PROLOG

    SciTech Connect

    DeSaram, H.

    1985-01-01

    Programming in Micro-PROLOG enables readers to carry out substantial projects of their own devising. It offers an explanation of how Micro-PROLOG works and a wide range of examples. Contents: Basic Processes; Some Built-in Commands; List Processing; Modules; Games and Puzzles; Augmented Turtle Graphics; Databases; Natural Language; Appendix.

  9. Chemical micro-sensor

    DOEpatents

    Ruggiero, Anthony J.

    2005-05-03

    An integrated optical capillary electrophoresis system for analyzing an analyte. A modulated optical pump beam impinges on an capillary containing the analyte/buffer solution which is separated by electrophoresis. The thermally-induced change in the index of refraction of light in said electrophoresis capillary is monitored using an integrated micro-interferometer. The interferometer includes a first interferometer arm intersecting the electrophoresis capillary proximate the excitation beam and a second, reference interferometer arm. Changes in index of refraction in the analyte measured by interrogating the interferometer state using white light interferometry and a phase-generated carrier demodulation technique. Background thermo-optical activity in the buffer solution is cancelled by splitting the pump beam and exciting pure buffer solution in a second section of capillary where it crosses the reference arm of the interferometer.

  10. Micro thrust and heat generator

    DOEpatents

    Garcia, Ernest J.

    1998-01-01

    A micro thrust and heat generator has a means for providing a combustion fuel source to an ignition chamber of the micro thrust and heat generator. The fuel is ignited by a ignition means within the micro thrust and heat generator's ignition chamber where it burns and creates a pressure. A nozzle formed from the combustion chamber extends outward from the combustion chamber and tappers down to a narrow diameter and then opens into a wider diameter where the nozzle then terminates outside of said combustion chamber. The pressure created within the combustion chamber accelerates as it leaves the chamber through the nozzle resulting in pressure and heat escaping from the nozzle to the atmosphere outside the micro thrust and heat generator. The micro thrust and heat generator can be microfabricated from a variety of materials, e.g., of polysilicon, on one wafer using surface micromachining batch fabrication techniques or high aspect ratio micromachining techniques (LIGA).

  11. Micro thrust and heat generator

    DOEpatents

    Garcia, E.J.

    1998-11-17

    A micro thrust and heat generator have a means for providing a combustion fuel source to an ignition chamber of the micro thrust and heat generator. The fuel is ignited by a ignition means within the micro thrust and heat generator`s ignition chamber where it burns and creates a pressure. A nozzle formed from the combustion chamber extends outward from the combustion chamber and tappers down to a narrow diameter and then opens into a wider diameter where the nozzle then terminates outside of said combustion chamber. The pressure created within the combustion chamber accelerates as it leaves the chamber through the nozzle resulting in pressure and heat escaping from the nozzle to the atmosphere outside the micro thrust and heat generator. The micro thrust and heat generator can be microfabricated from a variety of materials, e.g., of polysilicon, on one wafer using surface micromachining batch fabrication techniques or high aspect ratio micromachining techniques (LIGA). 30 figs.

  12. Micro UV detector

    NASA Astrophysics Data System (ADS)

    Cabalo, Jerry B.; Sickenberger, Richard; Underwood, William J.; Sickenberger, David W.

    2004-09-01

    A lightweight, tactical biological agent detection network offers the potential for a detect-to-warn capability against biological aerosol attacks. Ideally, this capability can be achieved by deploying the sensors upwind from the protected assets. The further the distance upwind, the greater the warning time. The technological challenge to this concept is the biological detection technology. Here, cost, size and power are major factors in selecting acceptable technologies. This is in part due to the increased field densities needed to cover the upwind area and the fact that the sensors, when deployed forward, must operate autonomously for long periods of time with little or no long-term logistical support. The Defense Advanced Research Project Agency"s (DARPA) Solid-state Ultraviolet Optical Source (SUVOS) program offers an enabling technology to achieving a detector compatible with this mission. As an optical source, these devices emit excitation wavelengths known to be useful in the detection of biological aerosols. The wavelength band is absorbed by the biological aerosol and results in visible fluorescence. Detection of a biological aerosol is based on the observed intensity of this fluorescence signal compared to a background reference. Historically this has been accomplished with emission sources that are outside the boundaries for low cost, low power sensors. The SUVOS technology, on the other hand, provides the same basic wavelengths needed for the detection process in a small, low power package. ECBC has initiated an effort to develop a network array based on micro UV detectors that utilize the SUVOS technology. This paper presents an overview of the micro UV detector and some of the findings to date. This includes the overall design philosophy, fluid flow calculations to maximize presentation of aerosol particles to the sources, and the fluorescence measurements.

  13. Micro-UV detector

    NASA Astrophysics Data System (ADS)

    Cabalo, Jerry B.; Sickenberger, Richard; Underwood, William J.; Sickenberger, David W.

    2004-12-01

    A lightweight, tactical biological agent detection network offers the potential for a detect-to-warn capability against biological aerosol attacks. Ideally, this capability can be achieved by deploying the sensors upwind from the protected assets. The further the distance upwind, the greater the warning time. The technological challenge to this concept is the biological detection technology. Here, cost, size and power are major factors in selecting acceptable technologies. This is in part due to the increased field densities needed to cover the upwind area and the fact that the sensors, when deployed forward, must operate autonomously for long periods of time with little or no long-term logistical support. The Defense Advanced Research Project Agency"s (DARPA) Solid-state Ultraviolet Optical Source (SUVOS) program offers an enabling technology to achieving a detector compatible with this mission. As an optical source, these devices emit excitation wavelengths known to be useful in the detection of biological aerosols. The wavelength band is absorbed by the biological aerosol and results in visible fluorescence. Detection of a biological aerosol is based on the observed intensity of this fluorescence signal compared to a background reference. Historically this has been accomplished with emission sources that are outside the boundaries for low cost, low power sensors. The SUVOS technology, on the other hand, provides the same basic wavelengths needed for the detection process in a small, low power package. ECBC has initiated an effort to develop a network array based on micro UV detectors that utilize the SUVOS technology. This paper presents an overview of the micro UV detector and some of the findings to date. This includes the overall design philosophy, fluid flow calculations to maximize presentation of aerosol particles to the sources, and the fluorescence measurements.

  14. [MicroRNAs in neurobiology].

    PubMed

    Kawahara, Yukio

    2008-12-01

    MicroRNAs have emerged as a new regulatory factor of gene expression. They mediate translational repression or degradation of their target mRNAs by RNA interference (RNAi). The expression of each microRNA is tightly regulated in a development- and cell-specific manner by various mechanisms such as blockade of let-7 family expression by Lin-28 or RNA editing. They also act as regulatory switches for development, organogenesis, and cellular differentiation or for controlling distinct functions that are required for the maintenance of each tissue and cell subtypes. The abundant expression of microRNAs as well as the exclusive expression of certain microRNAs in the central nervous system highlights their biological importance at all stages of neural development and in postmitotic and differentiated neurons. Further, some microRNAs, such as miRNA-134, and miRNA-132 are localized and are synthesized in part at synaptic sites in dendrites to regulate synaptic formation and plasticity. In addition to the imparting of basic knowledge about the biogenesis and mechanism of action of microRNAs, this review focuses on the recent advances in microRNA studies in neurobiology, including the expression pattern of microRNAs in the mammalian brain, the role of microRNAs in neural differentiation and maturation, formation and plasticity of synaptic connections, and maintenance of neural function such as the synthesis of the neurotransmitters in selected neurons. Finally, the possible connection between microRNA dysfunction and neurological diseases, and future implications for diagnosis, and treatment of defects in human brain development and neurodegenerative diseases are discussed.

  15. Rolling behavior of a micro-cylinder in adhesional contact

    PubMed Central

    Saito, Shigeki; Ochiai, Toshihiro; Yoshizawa, Fumikazu; Dao, Ming

    2016-01-01

    Understanding the rolling behavior of a micro-object is essential to establish the techniques of micro-manipulation and micro-assembly by mechanical means. Using a combined theoretical/computational approach, we studied the critical conditions of rolling resistance of an elastic cylindrical micro-object in adhesional contact with a rigid surface. Closed-form dimensionless expressions for the critical rolling moment, the initial rolling contact area, and the initial rolling angle were extracted after a systematic parametric study using finite element method (FEM) simulations. The total energy of this system is defined as the sum of three terms: the elastic energy stored in the deformed micro-cylinder, the interfacial energy within the contact area, and the mechanical potential energy that depends on the external moment applied to the cylindrical micro-object. A careful examination of the energy balance of the system surprisingly revealed that the rolling resistance per unit cylindrical length can be simply expressed by “work of adhesion times cylindrical radius” independent of the Young’s modulus. In addition, extending a linear elastic fracture mechanics based approach in the literature, we obtained the exact closed-form asymptotic solutions for the critical conditions for initial rolling; these asymptotic solutions were found in excellent agreement with the full-field FEM results. PMID:27677706

  16. Hybrid micro-/nanogels for optical sensing and intracellular imaging

    PubMed Central

    Wu, Weitai; Zhou, Shuiqin

    2010-01-01

    Hybrid micro-/nanogels are playing an increasing important part in a diverse range of applications, due to their tunable dimensions, large surface area, stable interior network structure, and a very short response time. We review recent advances and challenges in the developments of hybrid micro-/nanogels toward applications for optical sensing of pH, temperature, glucose, ions, and other species as well as for intracellular imaging. Due to their unique advantages, hybrid micro-/nanogels as optical probes are attracting substantial interests for continuous monitoring of chemical parameters in complex samples such as blood and bioreactor fluids, in chemical research and industry, and in food quality control. In particular, their intracellular probing ability enables the monitoring of the biochemistry and biophysics of live cells over time and space, thus contributing to the explanation of intricate biological processes and the development of novel diagnoses. Unlike most other probes, hybrid micro-/nanogels could also combine other multiple functions into a single probe. The rational design of hybrid micro-/nanogels will not only improve the probing applications as desirable, but also implement their applications in new arenas. With ongoing rapid advances in bionanotechnology, the well-designed hybrid micro-/nanogel probes will be able to provide simultaneous sensing, imaging diagnosis, and therapy toward clinical applications. PMID:22110866

  17. Combinations Therapies.

    PubMed

    Reinmuth, Niels; Reck, Martin

    2015-01-01

    Immunotherapy of cancer encompasses different strategies that elicit or enhance the immune response against tumors. The first results from clinical studies have provided promising data for the treatment of lung cancer patients with immunomodulating monotherapies. To improve the potential benefit of cancer immunotherapy, synergistic combinations of the various immunotherapy approaches or of different elements within each of the immunotherapy approaches are being explored. The rationale typically involves different but complementary mechanisms of action, eventually impinging on more than one immune system mechanism. As a prominent example, the simultaneous blockade of PD-1 and CTLA-4 is giving rise to therapeutic synergy, while still offering room for efficacy improvement. Moreover, combinations of immunomodulating agents with chemotherapy or targeted molecules are being tested. Animal models suggest that immunotherapies in combination with these various options offer evidence for synergistic effects and are likely to radically change cancer treatment paradigms. However, data obtained so far indicate that toxic side effects are also potentiated, which may even restrict the selection of patients that are suitable for these combinational approaches. Advancing the field of combinatorial immunotherapy will require changes in the way investigational agents are clinically developed as well as novel experimental end-points for efficacy evaluation. However, this combined therapeutic manipulation of both tumor and stromal cells may lead to a dramatic change in the therapeutic options of lung cancer patients in any disease stage that can only grossly be appreciated by the current studies. PMID:26384009

  18. A High-accuracy Micro-deformation Measurement Method

    NASA Astrophysics Data System (ADS)

    Jiang, Li

    2016-07-01

    The requirement for ever-increasing-resolution space cameras drives focal length and diameter of optical lenses be increasing. High-frequency vibration in the process of launching and complex environmental conditions of the outer space generate micro deformation in components of space cameras. As a result, images from the space cameras are blurred. Therefore, it is necessary to measure the micro deformations in components of space cameras in various experiment conditions. This paper presents a high-accuracy micro deformation measurement method. The method is implemented as follows: (1) fix Tungsten-steel balls onto a space camera being measured and measure the coordinate for each ball under the standard condition; (2) simulate high-frequency vibrations and environmental conditions like the outer space to measure coordinates for each ball under each combination of test conditions; and (3) compute the deviation of a coordinate of a ball under a test condition combination from the coordinate of the ball under the standard condition and the deviation is the micro deformation of the space camera component associated with the ball. This method was applied to micro deformation measurement for space cameras of different models. Measurement data for these space cameras validated the proposed method.

  19. Micro/nanofabricated solid-state thermoelectric generator devices for integrated high voltage power sources

    NASA Technical Reports Server (NTRS)

    Fleurial, J. P.; Snyder, G. J.; Patel, J.; Huang, C. K.; Ryan, M. A.; Averback, R.; Chen, G.; Hill, C.

    2002-01-01

    The Jet Propulsion Laboratory has been actively pursuing the development of thermoelectric micro/nanodevices that can be fabricated using a combination of electrochemical deposition and integrated circuit processing techniques.

  20. Analysis of the Multi Strategy Goal Programming for Micro-Grid Based on Dynamic ant Genetic Algorithm

    NASA Astrophysics Data System (ADS)

    Qiu, J. P.; Niu, D. X.

    Micro-grid is one of the key technologies of the future energy supplies. Take economic planning. reliability, and environmental protection of micro grid as a basis for the analysis of multi-strategy objective programming problems for micro grid which contains wind power, solar power, and battery and micro gas turbine. Establish the mathematical model of each power generation characteristics and energy dissipation. and change micro grid planning multi-objective function under different operating strategies to a single objective model based on AHP method. Example analysis shows that in combination with dynamic ant mixed genetic algorithm can get the optimal power output of this model.

  1. Hard X-ray micro-spectroscopy at Berliner Elektronenspeicherring für Synchrotronstrahlung II

    NASA Astrophysics Data System (ADS)

    Erko, A.; Zizak, I.

    2009-09-01

    The capabilities of the X-ray beamlines at Berliner Elektronenspeicherring für Synchrotronstrahlung II (BESSY II) for hard X-ray measurements with micro- and nanometer spatial resolution are reviewed. The micro-X-ray fluorescence analysis (micro-XRF), micro-extended X-ray absorption fine structure (micro-EXAFS), micro-X-ray absorption near-edge structure (micro-XANES) as well as X-ray standing wave technique (XSW), X-ray beam induced current (XBIC) in combination with micro-XRF and micro-diffraction as powerful methods for organic and inorganic sample characterization with synchrotron radiation are discussed. Mono and polycapillary optical systems were used for fine X-ray focusing down to 1 µm spot size with monochromatic and white synchrotron radiation. Polycapillary based confocal detection was applied for depth-resolved micro-XRF analysis with a volume resolution down to 3.4 · 10 - 6 mm 3. Standing wave excitation in waveguides was also applied to nano-EXAFS measurements with depth resolution on the order of 1 nm. Several examples of the methods and its applications in material research, biological investigations and metal-semiconductor interfaces analysis are given.

  2. Micro Continuous-Flow Synthesis of Metal Nanoparticles Using Micro Fluid Segment Technology

    NASA Astrophysics Data System (ADS)

    Knauer, Andrea; Köhler, J. Michael

    The micro segmented flow technique is very promising for the synthesis of metal nanoparticles, in particular for plasmonic nanoparticles and is very useful for combinatorial syntheses and screenings of new types of nanomaterials. In this chapter, the specific properties and technical as well as scientific challenges related to metal nanoparticles, the advantages of micro segmented flow and draw-backs of conventional synthesis for metal nanoparticles as well as the general applicability and the potential for the application of micro segmented flow for the preparation of metal and semiconductor nanoparticles are discussed. The specific conditions of micro segmented flow are described relating to the critical steps of reactant mixing, nucleation, and particle growth. It is shown that the intensification of local transport in the microfluidic system causes a significant improvement in particle homogeneity. In the formation and handling of metal particles, aspects of redox reactions, electrochemical parameters, and aspects of coordination chemistry have to be reconsidered. Ligands, which are able to interact with the metal ions in solution or with the forming nanoparticles, have a strong effect on the particle formation, their transport behavior, and interaction. The effect of fast reactant mixing supported by intensive segment-internal convection due to high flow rates is used in order to obtain uniform conditions for nucleation as well as for the particle growth. It is explained why non-spherical particles are of particular interest for different applications and how their quality can be improved by the application of microfluidic synthesis techniques, too. The formation of silver prisms by a micro continuous-flow synthesis in micro fluid segments will be given as a typical example allowing the tuning of the optical properties of the colloidal solutions. Finally, it is demonstrated that the micro segmented flow technique is well suited for an automated variation of

  3. Levitated micro-accelerometer.

    SciTech Connect

    Warne, Larry Kevin; Schmidt, Carrie Frances; Peterson, Kenneth Allen; Kravitz, Stanley H.; Renn, Rosemarie A.; Peter, Frank J.; Kinney, Ragon D.; Gilkey, Jeffrey C.

    2004-06-01

    The objective is a significant advancement in the state-of-the-art of accelerometer design for tactical grade (or better) applications. The design goals are <1 milli-G bias stability across environments and $200 cost. This quantum leap in performance improvement and cost reduction can only be achieved by a radical new approach, not incremental improvements to existing concepts. This novel levitated closed-loop accelerometer is implemented as a hybrid micromachine. The hybrid approach frees the designer from the limitations of any given monolithic process and dramatically expands the available design space. The design can be tailored to the dynamic range, resolution, bandwidth, and environmental requirements of the application while still preserving all of the benefits of monolithic MEMS fabrication - extreme precision, small size, low cost, and low power. An accelerometer was designed and prototype hardware was built, driving the successful development and refinement of several 'never been done before' fabrication processes. Many of these process developments are commercially valuable and are key enablers for the realization of a wide variety of useful micro-devices. While controlled levitation of a proof mass has yet to be realized, the overall design concept remains sound. This was clearly demonstrated by the stable and reliable closed-loop control of a proof mass at the test structure level. Furthermore, the hybrid MEMS implementation is the most promising approach for achieving the ambitious cost and performance targets. It is strongly recommended that Sandia remain committed to the original goal.

  4. Micro-Raman spectroscopy for meat type detection

    NASA Astrophysics Data System (ADS)

    De Biasio, M.; Stampfer, P.; Leitner, R.; Huck, C. W.; Wiedemair, V.; Balthasar, D.

    2015-06-01

    The recent horse meat scandal in Europe increased the demand for optical sensors that can identify meat type. Micro-Raman spectroscopy is a promising technique for the discrimination of meat types. Here, we present micro-Raman measurements of chicken, pork, turkey, mutton, beef and horse meat test samples. The data was analyzed with different combinations of data normalization and classification approaches. Our results show that Raman spectroscopy can discriminate between different meat types. Red and white meat are easily discriminated, however a sophisticated chemometric model is required to discriminate species within these groups.

  5. Forces in magnetospheric launching of micro-ejections

    NASA Astrophysics Data System (ADS)

    Cemeljic, Miljenko

    2013-07-01

    In 2D-axisymmetric simulations with our resistive MHD code Zeus-347 we show that micro-ejections, a quasi-stationary fast ejecta of matter of small mass and angular momentum fluxes, can be launched from a purely resistive magnetosphere above the disk gap. They are produced by a combination of pressure gradient and magnetic forces, in presence of ongoing magnetic reconnection along the boundary layer between the star and the disk, where a current sheet is formed. Mass flux of micro-ejections increases with increasing magnetic field strength and stellar rotation rate.

  6. Combination Light

    NASA Technical Reports Server (NTRS)

    1990-01-01

    The Rayovac TANDEM is an advanced technology combination work light and general purpose flashlight that incorporates several NASA technologies. The TANDEM functions as two lights in one. It features a long range spotlight and wide angle floodlight; simple one-hand electrical switching changes the beam from spot to flood. TANDEM developers made particular use of NASA's extensive research in ergonomics in the TANDEM's angled handle, convenient shape and different orientations. The shatterproof, water resistant plastic casing also draws on NASA technology, as does the shape and beam distance of the square diffused flood. TANDEM's heavy duty magnet that permits the light to be affixed to any metal object borrows from NASA research on rare earth magnets that combine strong magnetic capability with low cost. Developers used a NASA-developed ultrasonic welding technique in the light's interior.

  7. Micro thrust and heat generator

    SciTech Connect

    Garcia, E.J.

    1995-12-31

    The present invention relates generally to micromachines such as microengines or micromotors. More specifically, the invention is directed to a micro rocket which functions as a source of heat and thrust, and utilizes chemical energy to drive or power micromechanical apparatuses. The invention is adaptable to applications involving defense, bio-medical, manufacturing, consumer product, aviation, automotive, computer, inspection, and safety systems. A micro thrust and heat generator has a means for providing a combustion fuel source to an ignition chamber of the micro thrust and heat generator. The fuel is ignited by a ignition means within the micro thrust and heat generator`s ignition chamber where it burns and creates a pressure. A nozzle formed from the combustion chamber extends outward from the combustion chamber and tappers down to a narrow diameter and then opens into a wider diameter where the nozzle then terminates outside of said combustion chamber. The pressure created within the combustion chamber accelerates as it leaves the chamber through the nozzle resulting in pressure and heat escaping from the nozzle to the atmosphere outside the micro thrust and heat generator. The micro thrust and heat generator can be microfabricated from a variety of materials, e.g., of polysilicon, on one wafer using surface micromachining batch fabrication techniques or high aspect ratio micromachine techniques (LIGA).

  8. Micro Weather Station

    NASA Technical Reports Server (NTRS)

    Hoenk, Michael E.

    1999-01-01

    Improved in situ meteorological measurements in the troposphere and stratosphere are needed for studies of weather and climate, both as a primary data source and as validation for remote sensing instruments. Following the initial development and successful flight validation of the surface acoustic wave (SAW) hygrometer, the micro weather station program was directed toward the development of an integrated instrument, capable of accurate, in situ profiling of the troposphere, and small enough to fly on a radiosonde balloon for direct comparison with standard radiosondes. On April 23, 1998, working with Frank Schmidlin and Bob Olson of Wallops Island Flight Facility, we flew our instrument in a dual payload experiment, for validation and direct comparison with a Vaisala radiosonde. During that flight, the SAW dewpoint hygrometer measured frostpoint down to -76T at 44,000 feet. Using a laptop computer in radio contact with the balloon, we monitored data in real time, issued the cutdown command, and recovered the payload less than an hour after landing in White Sands Missile Range, 50 miles from the launch site in Hatch, New Mexico. Future flights will extend the intercomparison, and attempt to obtain in situ meteorological profiles from the surface through the tropopause. The SAW hygrometer was successfully deployed on the NASA DC8 as part of NASA's Third Convection and Moisture Experiment (CAMEX-3) during August and September, 1998. This field campaign was devoted to the study of hurricane tracking and intensification using NASA-funded aircraft. In situ humidity data from the SAW hygrometer are currently being analyzed and compared with data from other instruments on the DC8 and ER2 aircraft. Additional information is contained in the original.

  9. Micro hollow cathode discharges

    SciTech Connect

    Schoenbach, K.H.; Peterkin, F.E.; Verhappen, R.

    1995-12-31

    Hollow cathode discharges are glow discharges with the cathode fall and negative glow confined in a cavity in the cathode. For the discharge to develop, the cathode hole dimensions must be on the order of the mean free path. By reducing the cathode hole dimensions it is therefore possible to increase the pressure. Stable hollow cathode discharges in air have been observed at almost one atmosphere when the cathode diameter was reduced to 20 micrometers. In order to study the electrical parameters of a micro hollow cathode discharge, a set of experiments has been performed in argon at pressures in the torr range and a cathode hole diameter of 0.7 mm in molybdenum. The current-voltage characteristics and the appearance of the discharge plasma showed two distinct regions. At lower voltage or pressure the current varies linearly with voltage and the hollow cathode plasma is concentrated around the axis of the cathode hole (low glow mode). At higher values of voltage or pressure the current increases nonlinearly, up to a point where a transition into a low voltage hollow cathode arc was observed, and the plasma column expands and fills almost the entire cathode hole (high glow mode). Spectral measurements showed that the transition from the low glow mode into the high glow mode is related to an increased density of electrode vapor in the hollow cathode discharge. Up to the breakdown into a hollow cathode arc, the current voltage characteristic of the discharge has a positive slope. In this range, hollow cathode discharges can be operated in parallel without a ballast resistor.

  10. Micro electret power generators

    NASA Astrophysics Data System (ADS)

    Boland, Justin

    The taming of electricity and its widespread use allows people to see in the dark, to speak to one another instantaneously across the earth, and it allows retrieval of data from instruments sent out of the solar system. It is right to expect that the uses and demand for electricity will continue to grow, and to extend the ability to generate electricity; here two new micromachined devices for converting mechanical energy into electrical energy are presented. Aided by the wealth of micromachining process technology, generators that use an oscillatory motion to modify the physical structure of a capacitor with a built-in electric field provided by a permanent electret have been designed, built, and tested. The electret creates an electric field inside the capacitor structure, which induces mirror charge at some potential. The modification of the capacitor then generates an alternating displacement current through an external circuit, which provides useful electrical power. The electret microphone is a similar well known device for converting pressure waves into electrical signals by varying the distance between two charged capacitive plates. This work explores and proves feasible the ability to use mechanical forces to change the overlapping area of a charged capacitor structure and using mechanical forces to move a liquid into the gap of a charged capacitor structure, changing its permittivity to produce electricity. This work demonstrates 2.5mW of power from a 2cm diameter rotary generator at 12kRPM and 10[micro]w for a 0.1cm3 linear shaking generator at 60Hz.

  11. Review of Micro/Nanotechnologies for Microbial Biosensors

    PubMed Central

    Lim, Ji Won; Ha, Dogyeong; Lee, Jongwan; Lee, Sung Kuk; Kim, Taesung

    2015-01-01

    A microbial biosensor is an analytical device with a biologically integrated transducer that generates a measurable signal indicating the analyte concentration. This method is ideally suited for the analysis of extracellular chemicals and the environment, and for metabolic sensory regulation. Although microbial biosensors show promise for application in various detection fields, some limitations still remain such as poor selectivity, low sensitivity, and impractical portability. To overcome such limitations, microbial biosensors have been integrated with many recently developed micro/nanotechnologies and applied to a wide range of detection purposes. This review article discusses micro/nanotechnologies that have been integrated with microbial biosensors and summarizes recent advances and the applications achieved through such novel integration. Future perspectives on the combination of micro/nanotechnologies and microbial biosensors will be discussed, and the necessary developments and improvements will be strategically deliberated. PMID:26029689

  12. MEMS: A new approach to micro-optics

    SciTech Connect

    Sniegowski, J.J.

    1997-12-31

    MicroElectroMechanical Systems (MEMS) and their fabrication technologies provide great opportunities for application to micro-optical systems (MOEMS). Implementing MOEMS technology ranges from simple, passive components to complicated, active systems. Here, an overview of polysilicon surface micromachining MEMS combined with optics is presented. Recent advancements to the technology, which may enhance its appeal for micro-optics applications are emphasized. Of all the MEMS fabrication technologies, polysilicon surface micromachining technology has the greatest basis in and leverages the most the infrastructure for silicon integrated circuit fabrication. In that respect, it provides the potential for very large volume, inexpensive production of MOEMS. This paper highlights polysilicon surface micromachining technology in regards to its capability to provide both passive and active mechanical elements with quality optical elements.

  13. An osmolyte-based micro-volume ultrafiltration technique.

    PubMed

    Ghosh, Raja

    2014-12-01

    This paper discusses a novel, simple, and inexpensive micro-volume ultrafiltration technique for protein concentration, desalting, buffer exchange, and size-based protein purification. The technique is suitable for processing protein samples in a high-throughput mode. It utilizes a combination of capillary action, and osmosis for drawing water and other permeable species from a micro-volume sample droplet applied on the surface of an ultrafiltration membrane. A macromolecule coated on the permeate side of the membrane functions as the osmolyte. The action of the osmolyte could, if required, be augmented by adding a supersorbent polymer layer over the osmolyte. The mildly hydrophobic surface of the polymeric ultrafiltration membrane used in this study minimized sample droplet spreading, thus making it easy to recover the retained material after separation, without sample interference and cross-contamination. High protein recoveries were observed in the micro-volume ultrafiltration experiments described in the paper. PMID:25284741

  14. Micro-Particles as Electrostatic Probes for Plasma Sheath Diagnostic

    SciTech Connect

    Wolter, Matthias; Haass, Moritz; Ockenga, Taalke; Kersten, Holger; Blazec, Joseph; Basner, Ralf

    2008-09-07

    An interesting aspect in the research of complex (dusty) plasmas is the experimental study of the interaction of micro-particles of different sizes with the surrounding plasma for diagnostic purpose. In the plasma micro-disperse particles are negatively charged and confined in the sheath. The particles are trapped by an equilibrium of gravity, electric field force and ion drag force. From the behavior, local electric fields can be determined, e.g. particles are used as electrostatic probes. In combination with additional measurements of the plasma parameters with Langmuir probes and thermal probes as well as by comparison with an analytical sheath model, the structure of the sheath can be described. In the present work we focus on the behavior of micro-particles of different sizes and several plasma parameters e.g. the gas pressure and the rf-power.

  15. Controlled delivery of acyclovir from porous silicon micro- and nanoparticles

    NASA Astrophysics Data System (ADS)

    Maniya, Nalin H.; Patel, Sanjaykumar R.; Murthy, Z. V. P.

    2015-03-01

    In this work, micro- and nanoparticles of porous silicon (PSi) are demonstrated to act as effective carrier for the controlled delivery of acyclovir (ACV). PSi films prepared by electrochemical etching were fractured by ultrasonication to prepare micro- and nanoparticles. PSi native particles were thermally oxidized (TOPSi) and thermally hydrosilylated using undecylenic acid (UnPSi). PSi particles with three different surface chemistries were then loaded with ACV by physical adsorption and covalent attachment. Such particles were characterized by scanning electron microscopy, dynamic light scattering, and Fourier transform infrared spectroscopy. In vitro ACV release experiments in phosphate buffered saline showed sustained release behaviour from both micro- and nanoparticles and order of release was found to be native PSi > TOPSi > UnPSi. Drug release kinetics study using Korsmeyer-Peppas model suggested a combination of both drug diffusion and Si scaffold erosion based drug release mechanisms.

  16. The Laser MicroJet (LMJ): a multi-solution technology for high quality micro-machining

    NASA Astrophysics Data System (ADS)

    Mai, Tuan Anh; Richerzhagen, Bernold; Snowdon, Paul C.; Wood, David; Maropoulos, Paul G.

    2007-02-01

    The field of laser micromachining is highly diverse. There are many different types of lasers available in the market. Due to their differences in irradiating wavelength, output power and pulse characteristic they can be selected for different applications depending on material and feature size [1]. The main issues by using these lasers are heat damages, contamination and low ablation rates. This report examines on the application of the Laser MicroJet(R) (LMJ), a unique combination of a laser beam with a hair-thin water jet as a universal tool for micro-machining of MEMS substrates, as well as ferrous and non-ferrous materials. The materials include gallium arsenide (GaAs) & silicon wafers, steel, tantalum and alumina ceramic. A Nd:YAG laser operating at 1064 nm (infra red) and frequency doubled 532 nm (green) were employed for the micro-machining of these materials.

  17. Development of a low-cost micro-CMM for 3D micro/nano measurements

    NASA Astrophysics Data System (ADS)

    Fan, K. C.; Fei, Y. T.; Yu, X. F.; Chen, Y. J.; Wang, W. L.; Chen, F.; Liu, Y. S.

    2006-03-01

    A high-precision and low-cost micro-CMM (coordinate measuring machine) is under development. The expected measuring range is 25 × 25 × 10 mm3 and the resolution is 1 nm. In order to enhance the structural accuracy, some new ideas are integrated into the design, such as the arch-shape bridge for better stiffness and thermal accuracy, and the co-planar stage for less Abbe error. The linear diffraction grating interferometer and subdivision technique is proposed for position sensing to nanometre resolution. The focusing probe on the laser interferometer feedback spindle is structured in the Z-axis to guarantee the nanometre stability. In this report, the detailed design principles of the developed micro-CMM are described. The performance evaluation of each module of the prototype micro-CMM is presented. The positioning resolution of each axis to 1 nm can be achieved by combining the coarse and fine motion control on a piezo-ceramic linear motor. The Z-axis measurement can be controlled to within 15 nm repeatability. Parts of the positioning repeatability of the co-planar stage have been achieved to 30 nm. Some problems due to current techniques will be addressed.

  18. A micro solar heater for portable energy generation

    NASA Astrophysics Data System (ADS)

    Zimmerman, Raúl; Morrison, Graham; The, Owen; Rosengarten, Gary

    2007-12-01

    This study presents a new concept that combines microtechnology with solar thermal energy to provide a free portable energy source. A water-methanol mixture flows through an array of parallel microchannels which are fabricated into a silicon matrix using conventional micro-fabrication techniques. A vacuum layer is interposed between the channels and the external surface to thermally insulate the channels from the ambient temperature. A selective coating is deposited on one of the vacuum walls to absorb the short wavelength incoming radiation and reduce the long wavelength radiation, hence reducing the heat losses. A geometry and material optimization is still being developed in order to obtain the highest possible efficiency for the micro-heater, while keeping a low pressure drop in the micro-channels. The methanol outlet temperature is predicted to be higher than 250°C. This temperature is required for hydrogen production in a methanol reforming micro-reactor. Therefore, it is envisaged that the micro-solar heater will supply the thermal energy needed for hydrogen generation, that can later be used as fuel for microfuel cells. Both technologies can be integrated in a portable device.

  19. Enhanced selection of micro-aerobic pentachlorophenol degrading granular sludge.

    PubMed

    Lv, Yuancai; Chen, Yuancai; Song, Wenzhe; Hu, Yongyou

    2014-09-15

    Column-type combined reactors were designed to cultivate micro-aerobic pentachlorophenol (PCP) degrading granular sludge under oxygen-limited conditions (0.1-0.2 mgL(-1)) over 39-day experimental period. Micro-aerobic granular had both anaerobic activity (SMA: 2.34 mMCH4/hg VSS) and aerobic activity (SOUR: 2.21 mMO2/hg VSS). Metabolite analysis results revealed that PCP was sequentially dechlorinated to TCP, DCP, and eventually to MCP. Methanogens were not directly involved in the dechlorination of PCP, but might played a vital role in stabilizing the overall structure of the granule sludge. For Eubacteria, the Shannon Index (2.09 in inoculated granular sludge) increased both in micro-aerobic granular sludge (2.61) and PCP-degradation granular sludge (2.55). However, for Archaea, it decreased from 2.53 to 1.85 and 1.84, respectively. Although the Shannon Index demonstrated slight difference between micro-aerobic granular sludge and PCP-degradation granular sludge, the Principal Component Analysis (PCA) indicated obvious variance of the microbial composition, revealing significant effect of micro-aerobic condition and PCP on microbial community. Furthermore, nucleotide sequencing indicated that the main microorganisms for PCP degradation might be related to Actinobacterium and Sphingomonas. These results provided insights into situ bioremediation of environments contaminated by PCP and had practical implications for the strategies of PCP degradation.

  20. A review of micro/nano welding and its future developments.

    PubMed

    Guo, Kelvii W

    2009-01-01

    A review is given about the current state-of-the-art surrounding micro/nano scale welding/joining used in miniaturization or microsystems. Except for reviewing the applications of micro/nano welding/joining in various fields, such as microelectromechanical system (MEMS), micro total-analysis systems (microTAS), carbon nanotubes (CNTs) etc., the optimal equipments for micro/nano welding/joining, its corresponding future applications and research directions are discussed. Moreover, an extensive part of the paper is devoted to the introduction of new techniques, micro/nano laser and electron beam welding/joining. In turn, it is anticipated these techniques will be used in future micro/nano welding/joining applications. Meanwhile, because even smallest particles of dust can influence the results, more considerations are given to machine improvements that are required for its corresponding nano welding/joining. It will be one challenge for R&D efforts to combine the progress in micro/nano scales with that in miniaturization. This review provides a timely explanation of the literature surrounding the factors required for successful micro and nano welding/joining.

  1. Depth elemental imaging of forensic samples by confocal micro-XRF method.

    PubMed

    Nakano, Kazuhiko; Nishi, Chihiro; Otsuki, Kazunori; Nishiwaki, Yoshinori; Tsuji, Kouichi

    2011-05-01

    Micro-XRF is a significant tool for the analysis of small regions. A micro-X-ray beam can be created in the laboratory by various focusing X-ray optics. Previously, nondestructive 3D-XRF analysis had not been easy because of the high penetration of fluorescent X-rays emitted into the sample. A recently developed confocal micro-XRF technique combined with polycapillary X-ray lenses enables depth-selective analysis. In this paper, we applied a new tabletop confocal micro-XRF system to analyze several forensic samples, that is, multilayered automotive paint fragments and leather samples, for use in the criminaliztics. Elemental depth profiles and mapping images of forensic samples were successfully obtained by the confocal micro-XRF technique. Multilayered structures can be distinguished in forensic samples by their elemental depth profiles. However, it was found that some leather sheets exhibited heterogeneous distribution. To confirm the validity, the result of a conventional micro-XRF of the cross section was compared with that of the confocal micro-XRF. The results obtained by the confocal micro-XRF system were in approximate agreement with those obtained by the conventional micro-XRF. Elemental depth imaging was performed on the paint fragments and leather sheets to confirm the homogeneity of the respective layers of the sample. The depth images of the paint fragment showed homogeneous distribution in each layer expect for Fe and Zn. In contrast, several components in the leather sheets were predominantly localized.

  2. Coronary artery wall imaging in mice using osmium tetroxide and micro-computed tomography (micro-CT)

    SciTech Connect

    Pai, Vinay M.; Kozlowski, Megan; Donahue, Danielle; Miller, Elishiah; Xiao, Xianghui; Chen, Marcus Y.; Yu, Zu-Xi; Connelly, Patricia; Jeffries, Kenneth; Wen, Han

    2012-05-10

    The high spatial resolution of micro-computed tomography (micro-CT) is ideal for 3D imaging of coronary arteries in intact mouse heart specimens. Previously, micro-CT of mouse heart specimens utilized intravascular contrast agents that hardened within the vessel lumen and allowed a vascular cast to be made. However, for mouse coronary artery disease models, it is highly desirable to image coronary artery walls and highlight plaques. For this purpose, we describe an ex vivo contrast-enhanced micro-CT imaging technique based on tissue staining with osmium tetroxide (OsO{sub 4}) solution. As a tissue-staining contrast agent, OsO{sub 4} is retained in the vessel wall and surrounding tissue during the fixation process and cleared from the vessel lumens. Its high X-ray attenuation makes the artery wall visible in CT. Additionally, since OsO{sub 4} preferentially binds to lipids, it highlights lipid deposition in the artery wall. We performed micro-CT of heart specimens of 5- to 25-week-old C57BL/6 wild-type mice and 5- to 13-week-old apolipoprotein E knockout (apoE{sup -/-}) mice at 10 {mu}m resolution. The results show that walls of coronary arteries as small as 45 {mu}m in diameter are visible using a table-top micro-CT scanner. Similar image clarity was achieved with 1/2000th the scan time using a synchrotron CT scanner. In 13-week-old apoE mice, lipid-rich plaques are visible in the aorta. Our study shows that the combination of OsO{sub 4} and micro-CT permits the visualization of the coronary artery wall in intact mouse hearts.

  3. Micro Machining Enhances Precision Fabrication

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Advanced thermal systems developed for the Space Station Freedom project are now in use on the International Space Station. These thermal systems employ evaporative ammonia as their coolant, and though they employ the same series of chemical reactions as terrestrial refrigerators, the space-bound coolers are significantly smaller. Two Small Business Innovation Research (SBIR) contracts between Creare Inc. of Hanover, NH and Johnson Space Center developed an ammonia evaporator for thermal management systems aboard Freedom. The principal investigator for Creare Inc., formed Mikros Technologies Inc. to commercialize the work. Mikros Technologies then developed an advanced form of micro-electrical discharge machining (micro-EDM) to make tiny holes in the ammonia evaporator. Mikros Technologies has had great success applying this method to the fabrication of micro-nozzle array systems for industrial ink jet printing systems. The company is currently the world leader in fabrication of stainless steel micro-nozzles for this market, and in 2001 the company was awarded two SBIR research contracts from Goddard Space Flight Center to advance micro-fabrication and high-performance thermal management technologies.

  4. Tunable Micro- and Nanomechanical Resonators

    PubMed Central

    Zhang, Wen-Ming; Hu, Kai-Ming; Peng, Zhi-Ke; Meng, Guang

    2015-01-01

    Advances in micro- and nanofabrication technologies have enabled the development of novel micro- and nanomechanical resonators which have attracted significant attention due to their fascinating physical properties and growing potential applications. In this review, we have presented a brief overview of the resonance behavior and frequency tuning principles by varying either the mass or the stiffness of resonators. The progress in micro- and nanomechanical resonators using the tuning electrode, tuning fork, and suspended channel structures and made of graphene have been reviewed. We have also highlighted some major influencing factors such as large-amplitude effect, surface effect and fluid effect on the performances of resonators. More specifically, we have addressed the effects of axial stress/strain, residual surface stress and adsorption-induced surface stress on the sensing and detection applications and discussed the current challenges. We have significantly focused on the active and passive frequency tuning methods and techniques for micro- and nanomechanical resonator applications. On one hand, we have comprehensively evaluated the advantages and disadvantages of each strategy, including active methods such as electrothermal, electrostatic, piezoelectrical, dielectric, magnetomotive, photothermal, mode-coupling as well as tension-based tuning mechanisms, and passive techniques such as post-fabrication and post-packaging tuning processes. On the other hand, the tuning capability and challenges to integrate reliable and customizable frequency tuning methods have been addressed. We have additionally concluded with a discussion of important future directions for further tunable micro- and nanomechanical resonators. PMID:26501294

  5. Mechano-micro/nano systems

    NASA Astrophysics Data System (ADS)

    Horie, Mikio

    2004-10-01

    In recent years, the researches about Micro/Nano Systems are down actively in the bio-medical research fields, DNA research fields, chemical analysis systems fields, etc. In the results, a new materials and new functions in the systems are developed. In this invited paper, Mechano-Micro/Nano Systems, especially, motion systems are introduced. First, the research activities concerning the Mechano-Micro/Nano Systems in the world(MST2003, MEMS2003 and MEMS2004) and in Japan(Researech Projects on Nanotechnology and Materials in Ministry of Education, Culture, Sports, Science and Technology) are shown. Secondary, my research activities are introduced. As my research activities, (1) a comb-drive static actuator for the motion convert mechanisms, (2) a micro-nano fabrication method by use of FAB(Fast Atom Beam) machines, (3) a micro optical mirror manipulator for inputs-outputs optical switches, (4) a miniature pantograph mechanism with large-deflective hinges and links made of plastics are discussed and their performances are explained.

  6. Tunable micro- and nanomechanical resonators.

    PubMed

    Zhang, Wen-Ming; Hu, Kai-Ming; Peng, Zhi-Ke; Meng, Guang

    2015-01-01

    Advances in micro- and nanofabrication technologies have enabled the development of novel micro- and nanomechanical resonators which have attracted significant attention due to their fascinating physical properties and growing potential applications. In this review, we have presented a brief overview of the resonance behavior and frequency tuning principles by varying either the mass or the stiffness of resonators. The progress in micro- and nanomechanical resonators using the tuning electrode, tuning fork, and suspended channel structures and made of graphene have been reviewed. We have also highlighted some major influencing factors such as large-amplitude effect, surface effect and fluid effect on the performances of resonators. More specifically, we have addressed the effects of axial stress/strain, residual surface stress and adsorption-induced surface stress on the sensing and detection applications and discussed the current challenges. We have significantly focused on the active and passive frequency tuning methods and techniques for micro- and nanomechanical resonator applications. On one hand, we have comprehensively evaluated the advantages and disadvantages of each strategy, including active methods such as electrothermal, electrostatic, piezoelectrical, dielectric, magnetomotive, photothermal, mode-coupling as well as tension-based tuning mechanisms, and passive techniques such as post-fabrication and post-packaging tuning processes. On the other hand, the tuning capability and challenges to integrate reliable and customizable frequency tuning methods have been addressed. We have additionally concluded with a discussion of important future directions for further tunable micro- and nanomechanical resonators.

  7. Experimental investigation of electrohydrodynamic instabilities in micro channels

    NASA Astrophysics Data System (ADS)

    Eribol, P.; Uguz, A. K.

    2015-03-01

    An electric field is applied to destabilize the interface between two Newtonian and immiscible liquids flowing in a rectangular micro channel. The liquids are pumped into the micro channel with a syringe pump and a DC electric field is applied either parallel or normal to the flat interface between these liquids. The two liquids used in the experiments are a combination of ethylene glycol, different viscosity silicone oils, castor oil, and olive oil. The onset of electrohydrodynamic instability is investigated for various parameters, including the ratios of the flow rates, and viscosities of the liquids, the width of the micro channel, and the direction of the applied electric field. The order of the voltage applied to destabilize the interface is in the range 95 and 1190 V. The results of the experiments show that an increase in the viscosity ratio and the flow rate ratio of silicone oil to ethylene glycol have a stabilizing effect. It is also found that the important parameter to determine the critical voltage is the flow rate ratio, not the individual flow rates of the liquids. Also, as the width of the micro channel increases, the critical voltage increases. Lastly, for the liquid combinations used in the experiments, the interface could not be destabilized under the influence of a parallel electric field.

  8. Non corrosive micro coolers with matched CTE

    NASA Astrophysics Data System (ADS)

    Ebert, Thomas; Meiners, Wilhelm; Pajunk, Markus

    2006-02-01

    At Photonics West 2005 a new technology was described for building a new, non corrosive micro cooling heat sink for diode lasers made of stainless steel with the procedure of three dimensional laser melting. Due to the thermal conductivity, which is 20 times worse than the conductivity of copper, first test leads to the result, that it is not possible to compensate the worst thermal conductivity by an optimized inner structure, regarding wall thicknesses and flow rate. So the solution was searching a different material, with a better thermal conductivity to achieve a thermal over all resistance that is usable for the cooling of high power laser diodes. Searching that material leads to a special nickel alloy in the field of nuclear industry. The new generation of micro coolers are named TEX series. All TEX Series coolers were made out of a special nickel alloy, specially developed as a corrosion protection material. Therefore, the TEX coolers have excellent corrosion resistance. In addition, due to the manner and way of using three dimensional laser melting, the surface of the inner structure was hardened. The hardening HV1 is 380, so that there is no danger regarding erosion or a combination of erosion and corrosion. Metallization and soldering the semi conductor also had been tested. The commonly used structure with Nickel and Gold is possible as well as the metallization only with gold. With both variations the semi conductor can be soldered and the connection to the cooler surface is very strong.

  9. Flight Qualified Micro Sun Sensor

    NASA Technical Reports Server (NTRS)

    Liebe, Carl Christian; Mobasser, Sohrab; Wrigley, Chris; Schroeder, Jeffrey; Bae, Youngsam; Naegle, James; Katanyoutanant, Sunant; Jerebets, Sergei; Schatzel, Donald; Lee, Choonsup

    2007-01-01

    A prototype small, lightweight micro Sun sensor (MSS) has been flight qualified as part of the attitude-determination system of a spacecraft or for Mars surface operations. The MSS has previously been reported at a very early stage of development in NASA Tech Briefs, Vol. 28, No. 1 (January 2004). An MSS is essentially a miniature multiple-pinhole electronic camera combined with digital processing electronics that functions analogously to a sundial. A micromachined mask containing a number of microscopic pinholes is mounted in front of an active-pixel sensor (APS). Electronic circuits for controlling the operation of the APS, readout from the pixel photodetectors, and analog-to-digital conversion are all integrated onto the same chip along with the APS. The digital processing includes computation of the centroids of the pinhole Sun images on the APS. The spacecraft computer has the task of converting the Sun centroids into Sun angles utilizing a calibration polynomial. The micromachined mask comprises a 500-micron-thick silicon wafer, onto which is deposited a 57-nm-thick chromium adhesion- promotion layer followed by a 200-nm-thick gold light-absorption layer. The pinholes, 50 microns in diameter, are formed in the gold layer by photolithography. The chromium layer is thin enough to be penetrable by an amount of Sunlight adequate to form measurable pinhole images. A spacer frame between the mask and the APS maintains a gap of .1 mm between the pinhole plane and the photodetector plane of the APS. To minimize data volume, mass, and power consumption, the digital processing of the APS readouts takes place in a single field-programmable gate array (FPGA). The particular FPGA is a radiation- tolerant unit that contains .32,000 gates. No external memory is used so the FPGA calculates the centroids in real time as pixels are read off the APS with minimal internal memory. To enable the MSS to fit into a small package, the APS, the FPGA, and other components are mounted

  10. Micro electric propulsion feasibility

    NASA Technical Reports Server (NTRS)

    Aston, Graeme; Aston, Martha

    1992-01-01

    , minimal detectability and low cost are requirements. All these miniature spacecraft share a common characteristic: because of their on-board electronic equipment they have, by design, solar order 50-100 W. In a relative sense, such spacecraft are power rich when compared to other larger spacecraft. This power rich situation is offset by very tight mass budgets, which make reductions in propellant mass requirements a key issue in meeting overall spacecraft minimum mass goals. In principle, power rich and propellant poor brilliant pebbles class spacecraft can benefit from using high specific impulse electric propulsion to reduce chemical propellant mass requirements. However, at power levels of order 50 W, arcjets cannot be made to function, ion thrusters are too complex and heavy and resistojets have too low a specific impulse. Recognizing these capability limitations in existing electric propulsion technology, the SDIO/IST sponsored the Phase I SBIR Micro Electric Propulsion (MEP) thruster study described in this report. The objective of this study was to examine the feasibility of developing a very simple, low mass and small volume, electric thruster for operation on hydrazine at less than 100 W of input power. The feasibility of developing such a MEP thruster was successfully demonstrated by EPL by the discovery of a novel plasma acceleration process. The sections in this report summarize the approach, test results and major accomplishments of this proof-of-concept program.

  11. Development of Micro UAV Swarms

    NASA Astrophysics Data System (ADS)

    Bürkle, Axel; Leuchter, Sandro

    Some complex application scenarios for micro UAVs (Unmanned Aerial Vehicles) call for the formation of swarms of multiple drones. In this paper a platform for the creation of such swarms is presented. It consists of modified commercial quadrocopters and a self-made ground control station software architecture. Autonomy of individual drones is generated through a micro controller equipped video camera. Currently it is possible to fly basic maneuvers autonomously, such as take-off, fly to position, and landing. In the future the camera's image processing capabilities will be used to generate additional control information. Different co-operation strategies for teams of UAVs are currently evaluated with an agent based simulation tool. Finally complex application scenarios for multiple micro UAVs are presented.

  12. Micro-facies of Dead Sea sediments

    NASA Astrophysics Data System (ADS)

    Neugebauer, Ina; Schwab, Markus J.; Brauer, Achim; Frank, Ute; Dulski, Peter; Kitagawa, Hiroyuki; Enzel, Yehouda; Waldmann, Nicolas; Ariztegui, Daniel; Drilling Party, Dsddp

    2013-04-01

    , 2006). Combining micro-facies analyses of these shallow and deep basin environments allows depicting sedimentation processes and is a key for understanding climatically-induced sediment formation in the DSB at sub-annual timescales. Enzel et al., 2008. Global and Planetary Change 60, 165-192. Migowski et al., 2004. Earth and Planetary Science Letters 222, 301-314. Migowski et al., 2006. Quaternary Research 66 (3), 421-431.

  13. Micro-column plasma emission liquid chromatograph

    DOEpatents

    Gay, Don D.

    1984-01-01

    In a direct current plasma emission spectrometer for use in combination with a micro-column liquid chromatograph, an improved plasma source unit. The plasma source unit includes a quartz capillary tube having an inlet means, outlet off gas means and a pair of spaced electrodes defining a plasma region in the tube. The inlet means is connected to and adapted to receive eluant of the liquid chromatograph along with a stream of plasma-forming gas. There is an opening through the wall of the capillary tube penetrating into the plasma region. A soft glass capillary light pipe is disposed at the opening, is connected to the spectrometer, and is adapted to transmit light passing from the plasma region to the spectrometer. There is also a source of electromotive force connected to the electrodes sufficient to initiate and sustain a plasma in the plasma region of the tube.

  14. Homogenization in micro-plasticity

    NASA Astrophysics Data System (ADS)

    Berdichevsky, Victor L.

    2005-11-01

    Homogenized descriptions of plasticity on micro- and macro-scale are essentially different. A key distinction is that the energy of micron-size specimens, in contrast to that of macro-specimens, is not a functional of integral characteristics of the dislocation networks. Thus, energy must be considered as an independent characteristic of the body which is additional to all other characteristics. In this paper, a homogenized description of dislocation motion on the micro-scale is proposed. The theory is considered for the case of anti-plane constrained shear which admits an analytical treatment.

  15. Micro-machined calorimetric biosensors

    DOEpatents

    Doktycz, Mitchel J.; Britton, Jr., Charles L.; Smith, Stephen F.; Oden, Patrick I.; Bryan, William L.; Moore, James A.; Thundat, Thomas G.; Warmack, Robert J.

    2002-01-01

    A method and apparatus are provided for detecting and monitoring micro-volumetric enthalpic changes caused by molecular reactions. Micro-machining techniques are used to create very small thermally isolated masses incorporating temperature-sensitive circuitry. The thermally isolated masses are provided with a molecular layer or coating, and the temperature-sensitive circuitry provides an indication when the molecules of the coating are involved in an enthalpic reaction. The thermally isolated masses may be provided singly or in arrays and, in the latter case, the molecular coatings may differ to provide qualitative and/or quantitative assays of a substance.

  16. MicroRNA expression profiling using microarrays.

    PubMed

    Love, Cassandra; Dave, Sandeep

    2013-01-01

    MicroRNAs are small noncoding RNAs which are able to regulate gene expression at both the transcriptional and translational levels. There is a growing recognition of the role of microRNAs in nearly every tissue type and cellular process. Thus there is an increasing need for accurate quantitation of microRNA expression in a variety of tissues. Microarrays provide a robust method for the examination of microRNA expression. In this chapter, we describe detailed methods for the use of microarrays to measure microRNA expression and discuss methods for the analysis of microRNA expression data. PMID:23666707

  17. The collection of MicroED data for macromolecular crystallography.

    PubMed

    Shi, Dan; Nannenga, Brent L; de la Cruz, M Jason; Liu, Jinyang; Sawtelle, Steven; Calero, Guillermo; Reyes, Francis E; Hattne, Johan; Gonen, Tamir

    2016-05-01

    The formation of large, well-ordered crystals for crystallographic experiments remains a crucial bottleneck to the structural understanding of many important biological systems. To help alleviate this problem in crystallography, we have developed the MicroED method for the collection of electron diffraction data from 3D microcrystals and nanocrystals of radiation-sensitive biological material. In this approach, liquid solutions containing protein microcrystals are deposited on carbon-coated electron microscopy grids and are vitrified by plunging them into liquid ethane. MicroED data are collected for each selected crystal using cryo-electron microscopy, in which the crystal is diffracted using very few electrons as the stage is continuously rotated. This protocol gives advice on how to identify microcrystals by light microscopy or by negative-stain electron microscopy in samples obtained from standard protein crystallization experiments. The protocol also includes information about custom-designed equipment for controlling crystal rotation and software for recording experimental parameters in diffraction image metadata. Identifying microcrystals, preparing samples and setting up the microscope for diffraction data collection take approximately half an hour for each step. Screening microcrystals for quality diffraction takes roughly an hour, and the collection of a single data set is ∼10 min in duration. Complete data sets and resulting high-resolution structures can be obtained from a single crystal or by merging data from multiple crystals.

  18. The collection of MicroED data for macromolecular crystallography.

    PubMed

    Shi, Dan; Nannenga, Brent L; de la Cruz, M Jason; Liu, Jinyang; Sawtelle, Steven; Calero, Guillermo; Reyes, Francis E; Hattne, Johan; Gonen, Tamir

    2016-05-01

    The formation of large, well-ordered crystals for crystallographic experiments remains a crucial bottleneck to the structural understanding of many important biological systems. To help alleviate this problem in crystallography, we have developed the MicroED method for the collection of electron diffraction data from 3D microcrystals and nanocrystals of radiation-sensitive biological material. In this approach, liquid solutions containing protein microcrystals are deposited on carbon-coated electron microscopy grids and are vitrified by plunging them into liquid ethane. MicroED data are collected for each selected crystal using cryo-electron microscopy, in which the crystal is diffracted using very few electrons as the stage is continuously rotated. This protocol gives advice on how to identify microcrystals by light microscopy or by negative-stain electron microscopy in samples obtained from standard protein crystallization experiments. The protocol also includes information about custom-designed equipment for controlling crystal rotation and software for recording experimental parameters in diffraction image metadata. Identifying microcrystals, preparing samples and setting up the microscope for diffraction data collection take approximately half an hour for each step. Screening microcrystals for quality diffraction takes roughly an hour, and the collection of a single data set is ∼10 min in duration. Complete data sets and resulting high-resolution structures can be obtained from a single crystal or by merging data from multiple crystals. PMID:27077331

  19. Window-assisted nanosphere lithography for vacuum micro-nano-electronics

    SciTech Connect

    Li, Nannan; Pang, Shucai; Yan, Fei; Chen, Lei; Jin, Dazhi; Xiang, Wei; Zhang, De; Zeng, Baoqing

    2015-04-15

    Development of vacuum micro-nano-electronics is quite important for combining the advantages of vacuum tubes and solid-state devices but limited by the prevailing fabricating techniques which are expensive, time consuming and low-throughput. In this work, window-assisted nanosphere lithography (NSL) technique was proposed and enabled the low-cost and high-efficiency fabrication of nanostructures for vacuum micro-nano-electronic devices, thus allowing potential applications in many areas. As a demonstration, we fabricated high-density field emitter arrays which can be used as cold cathodes in vacuum micro-nano-electronic devices by using the window-assisted NSL technique. The details of the fabricating process have been investigated. This work provided a new and feasible idea for fabricating nanostructure arrays for vacuum micro-nano-electronic devices, which would spawn the development of vacuum micro-nano-electronics.

  20. Analysis of the optical force in the Micro Ring Resonator.

    PubMed

    Einat, Avigdor; Levy, Uriel

    2011-10-10

    We study the optical force in a micro ring resonator coupled to a bus waveguide, using the coupled mode theory and a numerical Finite Element Method. We show that the resonance enhancement of the force is diminished by the opposing contributions of the attractive and the repulsive forces related to the symmetric and the anti symmetric modes in the coupling region. We show that this limiting factor can be removed by adding asymmetry to the system, e.g. by modifying one of the waveguides. Furthermore, we study for the first time a combined system in which the micro ring resonator is coupled to a one dimensional photonic crystal waveguide. This modified geometry allows further enhancement of the optical force via the combination of optical resonances and slow light effect.

  1. Analysis of the optical force in the Micro Ring Resonator.

    PubMed

    Einat, Avigdor; Levy, Uriel

    2011-10-10

    We study the optical force in a micro ring resonator coupled to a bus waveguide, using the coupled mode theory and a numerical Finite Element Method. We show that the resonance enhancement of the force is diminished by the opposing contributions of the attractive and the repulsive forces related to the symmetric and the anti symmetric modes in the coupling region. We show that this limiting factor can be removed by adding asymmetry to the system, e.g. by modifying one of the waveguides. Furthermore, we study for the first time a combined system in which the micro ring resonator is coupled to a one dimensional photonic crystal waveguide. This modified geometry allows further enhancement of the optical force via the combination of optical resonances and slow light effect. PMID:21997050

  2. Recent progress with the MicroCAT gaseous imaging detector

    NASA Astrophysics Data System (ADS)

    Orthen, A.; Wagner, H.; Besch, H. J.; Menk, R. H.; Sarvestani, A.; Walenta, A. H.; Walliser, H.

    2002-02-01

    The detector, presented here, is a combination of the MicroCAT gas gain device with a truly two-dimensional interpolating readout structure. A new spacer concept has been developed to keep a constant distance between the gas gain and the readout structure, also for increased detection areas. Thus, it was possible to enlarge the sensitive area by a factor 16 to 56×56 mm2. The interpolating anode combines the advantages of a pure pixel device with a reduced number of electronic readout channels, nevertheless reaching a spatial resolution of about 200 μm. In order to understand the physical behaviour of the two-dimensional interpolating structure and to optimise this device for different applications a numerical simulation of the signal development was performed. Recent results of the MicroCAT detector demonstrate the applicability of this detector system in the field of protein crystallography and time resolved measurements in the microsecond range.

  3. On-chip micro-power: three-dimensional structures for micro-batteries and micro-supercapacitors

    NASA Astrophysics Data System (ADS)

    Beidaghi, Majid; Wang, Chunlei

    2010-04-01

    With the miniaturization of portable electronic devices, there is a demand for micro-power source which can be integrated on the semiconductor chips. Various micro-batteries have been developed in recent years to generate or store the energy that is needed by microsystems. Micro-supercapacitors are also developed recently to couple with microbatteries and energy harvesting microsystems and provide the peak power. Increasing the capacity per footprint area of micro-batteries and micro-supercapacitors is a great challenge. One promising route is the manufacturing of three dimensional (3D) structures for these micro-devices. In this paper, the recent advances in fabrication of 3D structure for micro-batteries and micro-supercapacitors are briefly reviewed.

  4. Fabrication of a Flexible Micro Temperature Sensor for Micro Reformer Applications

    PubMed Central

    Lee, Chi-Yuan; Lin, Chien-Hen; Lo, Yi-Man

    2011-01-01

    Micro reformers still face obstacles in minimizing their size, decreasing the concentration of CO, conversion efficiency and the feasibility of integrated fabrication with fuel cells. By using a micro temperature sensor fabricated on a stainless steel-based micro reformer, this work attempts to measure the inner temperature and increase the conversion efficiency. Micro temperature sensors on a stainless steel substrate are fabricated using micro-electro-mechanical systems (MEMS) and then placed separately inside the micro reformer. Micro temperature sensors are characterized by their higher accuracy and sensitivity than those of a conventional thermocouple. To the best of our knowledge, micro temperature sensors have not been embedded before in micro reformers and commercial products, therefore, this work presents a novel approach to integrating micro temperature sensors in a stainless steel-based micro reformer in order to evaluate inner local temperature distributions and enhance reformer performance. PMID:22163817

  5. Murillo's paintings revealed by spectroscopic techniques and dedicated laboratory-made micro X-ray diffraction.

    PubMed

    Duran, A; Siguenza, M B; Franquelo, M L; Jimenez de Haro, M C; Justo, A; Perez-Rodriguez, J L

    2010-06-25

    This paper describes one of the first case studies using micro-diffraction laboratory-made systems to analyse painting cross-sections. Pigments, such as lead white, vermilion, red ochre, red lac, lapis lazuli, smalt, lead tin yellow type I, massicot, ivory black, lamp black and malachite, were detected in cross-sections prepared from six Bartolomé Esteban Murillo paintings by micro-Raman and micro-XRD combined with complementary techniques (optical microscopy, SEM-EDS, and FT-IR). The use of micro-XRD was necessary due to the poor results obtained with conventional XRD. In some cases, pigment identification was only possible by combining results from the different analytical techniques utilised in this study.

  6. Murillo's paintings revealed by spectroscopic techniques and dedicated laboratory-made micro X-ray diffraction.

    PubMed

    Duran, A; Siguenza, M B; Franquelo, M L; Jimenez de Haro, M C; Justo, A; Perez-Rodriguez, J L

    2010-06-25

    This paper describes one of the first case studies using micro-diffraction laboratory-made systems to analyse painting cross-sections. Pigments, such as lead white, vermilion, red ochre, red lac, lapis lazuli, smalt, lead tin yellow type I, massicot, ivory black, lamp black and malachite, were detected in cross-sections prepared from six Bartolomé Esteban Murillo paintings by micro-Raman and micro-XRD combined with complementary techniques (optical microscopy, SEM-EDS, and FT-IR). The use of micro-XRD was necessary due to the poor results obtained with conventional XRD. In some cases, pigment identification was only possible by combining results from the different analytical techniques utilised in this study. PMID:20541637

  7. Interior micro-CT with an offset detector

    SciTech Connect

    Sharma, Kriti Sen; Gong, Hao; Ghasemalizadeh, Omid; Yu, Hengyong; Wang, Ge

    2014-06-15

    Purpose: The size of field-of-view (FOV) of a microcomputed tomography (CT) system can be increased by offsetting the detector. The increased FOV is beneficial in many applications. All prior investigations, however, have been focused to the case in which the increased FOV after offset-detector acquisition can cover the transaxial extent of an object fully. Here, the authors studied a new problem where the FOV of a micro-CT system, although increased after offset-detector acquisition, still covers an interior region-of-interest (ROI) within the object. Methods: An interior-ROI-oriented micro-CT scan with an offset detector poses a difficult reconstruction problem, which is caused by both detector offset and projection truncation. Using the projection completion techniques, the authors first extended three previous reconstruction methods from offset-detector micro-CT to offset-detector interior micro-CT. The authors then proposed a novel method which combines two of the extended methods using a frequency split technique. The authors tested the four methods with phantom simulations at 9.4%, 18.8%, 28.2%, and 37.6% detector offset. The authors also applied these methods to physical phantom datasets acquired at the same amounts of detector offset from a customized micro-CT system. Results: When the detector offset was small, all reconstruction methods showed good image quality. At large detector offset, the three extended methods gave either visible shading artifacts or high deviation of pixel value, while the authors’ proposed method demonstrated no visible artifacts and minimal deviation of pixel value in both the numerical simulations and physical experiments. Conclusions: For an interior micro-CT with an offset detector, the three extended reconstruction methods can perform well at a small detector offset but show strong artifacts at a large detector offset. When the detector offset is large, the authors’ proposed reconstruction method can outperform the three

  8. Micro-machined resonator oscillator

    DOEpatents

    Koehler, D.R.; Sniegowski, J.J.; Bivens, H.M.; Wessendorf, K.O.

    1994-08-16

    A micro-miniature resonator-oscillator is disclosed. Due to the miniaturization of the resonator-oscillator, oscillation frequencies of one MHz and higher are utilized. A thickness-mode quartz resonator housed in a micro-machined silicon package and operated as a telemetered sensor beacon'' that is, a digital, self-powered, remote, parameter measuring-transmitter in the FM-band. The resonator design uses trapped energy principles and temperature dependence methodology through crystal orientation control, with operation in the 20--100 MHz range. High volume batch-processing manufacturing is utilized, with package and resonator assembly at the wafer level. Unique design features include squeeze-film damping for robust vibration and shock performance, capacitive coupling through micro-machined diaphragms allowing resonator excitation at the package exterior, circuit integration and extremely small (0.1 in. square) dimensioning. A family of micro-miniature sensor beacons is also disclosed with widespread applications as bio-medical sensors, vehicle status monitors and high-volume animal identification and health sensors. The sensor family allows measurement of temperatures, chemicals, acceleration and pressure. A microphone and clock realization is also available. 21 figs.

  9. Micro-machined resonator oscillator

    DOEpatents

    Koehler, Dale R.; Sniegowski, Jeffry J.; Bivens, Hugh M.; Wessendorf, Kurt O.

    1994-01-01

    A micro-miniature resonator-oscillator is disclosed. Due to the miniaturization of the resonator-oscillator, oscillation frequencies of one MHz and higher are utilized. A thickness-mode quartz resonator housed in a micro-machined silicon package and operated as a "telemetered sensor beacon" that is, a digital, self-powered, remote, parameter measuring-transmitter in the FM-band. The resonator design uses trapped energy principles and temperature dependence methodology through crystal orientation control, with operation in the 20-100 MHz range. High volume batch-processing manufacturing is utilized, with package and resonator assembly at the wafer level. Unique design features include squeeze-film damping for robust vibration and shock performance, capacitive coupling through micro-machined diaphragms allowing resonator excitation at the package exterior, circuit integration and extremely small (0.1 in. square) dimensioning. A family of micro-miniature sensor beacons is also disclosed with widespread applications as bio-medical sensors, vehicle status monitors and high-volume animal identification and health sensors. The sensor family allows measurement of temperatures, chemicals, acceleration and pressure. A microphone and clock realization is also available.

  10. [Micro-invasive glaucoma surgery].

    PubMed

    Achiron, Asaf; Sharif, Nardeen; Achiron, Romi Noy; Nisimov, Sagee; Burgansky-Eliash, Sagee

    2014-10-01

    Intraocular pressure (IOP) reduction is the current treatment in glaucoma. In recent years, minimally invasive glaucoma surgery (MIGS) has been added to the arsenal of surgical options. MIGS can reduce trabecular meshwork resistance to outflow and decrease the IOP with mild side effects. In this article, we review the clinical experience gathered with iSTENT, Bypass, Gold Micro Shunt and the Trabectome.

  11. Switch on Micro*scope!

    ERIC Educational Resources Information Center

    Roland, Sarah; Bahr, Michele; Olendzenski, Lorraine; Patterson, David J.

    2005-01-01

    Scientists at the Marine Biological Laboratory in Woods Hole, Massachusetts, have created micro*scope, a free, searchable knowledge environment for exploring the microbial world. Microbiology can easily be incorporated into the curriculum, because microbial communities are easy to access. Organisms grow quickly, making certain arrays of…

  12. Micro-Encapsulation of Probiotics

    NASA Astrophysics Data System (ADS)

    Meiners, Jean-Antoine

    Micro-encapsulation is defined as the technology for packaging with the help of protective membranes particles of finely ground solids, droplets of liquids or gaseous materials in small capsules that release their contents at controlled rates over prolonged periods of time under the influences of specific conditions (Boh, 2007). The material encapsulating the core is referred to as coating or shell.

  13. Micro-Rockets for the Classroom.

    ERIC Educational Resources Information Center

    Huebner, Jay S.; Fletcher, Alice S.; Cato, Julia A.; Barrett, Jennifer A.

    1999-01-01

    Compares micro-rockets to commercial models and water rockets. Finds that micro-rockets are more advantageous because they are constructed with inexpensive and readily available materials and can be safely launched indoors. (CCM)

  14. Micro Cooling, Heating, and Power (Micro-CHP) and Bio-Fuel Center, Mississippi State University

    SciTech Connect

    Louay Chamra

    2008-09-26

    specifications is observed. Case study data for various micro-CHP system configurations have been discussed and compared. Comparisons are made of the different prime mover/fuel combinations. Also, micro- CHP monthly energy cost results are compared for each system configuration to conventional monthly utility costs for equivalent monthly building power, heating, and cooling requirements.

  15. Characterization and differentiation of normal and abnormal semen samples using micro-Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Huang, Zufang; Chen, Xiwen; Chen, Jinhua; Li, Yongzeng; Lei, Jinping; Chen, Rong

    2012-12-01

    Growth in the percentage of male infertility has caused extensive concerns. The fast and reliable method is urgently required for diagnosis of semen samples. In our study, micro-Raman spectroscopy was employed to characterize and differentiate the normal and abnormal semen samples based on the differences of their specific Raman spectra which originated from biochemical components. Our preliminary results demonstrate that micro-Raman spectroscopy combined with multivariate analysis methods has the potential of being used to detect and differentiate semen samples.

  16. MicroRNAs in Sjögren’s syndrome as a prototypic autoimmune disease

    PubMed Central

    Alevizos, Ilias; Illei, Gabor G

    2012-01-01

    MicroRNAs are endogenous non-coding RNAs, approximately 22 nucleotides in length. They regulate gene expression and are important in a wide range of physiological and pathological processes. MicroRNA expression is tightly regulated during hematopoiesis and lymphoid cell differentiation and disruption of the entire microRNA network or selected microRNAs may lead to dysregulated immune responses. Abnormalities in microRNA expression related to inflammatory cytokines, Th-17 and regulatory T cells as well as B cells have been described in several autoimmune diseases. Sjögren’s syndrome is characterized by features of systemic autoimmunity and chronic inflammation and dysfunction in exocrine organs. Its clinical characteristics along with the relatively easy access to the target tissue and its product makes Sjögren’s syndrome appealing to study many aspects of microRNAs in a systemic autoimmune disease, such as their potential as diagnostic or prognostic biomarkers and their role in pathogenesis of autoimmunity, inflammation or organ dysfunction. Encouraging preliminary data from pilot studies in Sjögren’s syndrome demonstrate the potential of microRNAs as putative diagnostic and prognostic biomarker candidates which should be tested in larger more definite studies. Combining the comparison of microRNA expression profiles between various clinical subsets of Sjögren’s syndrome with bioinformatic modeling tools may predict formerly unsuspected pathways which may contribute to the disease process and lead to the generation of testable novel hypothesis of pathogenesis. PMID:20457282

  17. Micro Channel/Multibus-II Interface Circuit

    NASA Technical Reports Server (NTRS)

    D'Ambrose, John J.; Jaworski, Richard C.; Heise, Nyles N.; Thornton, David N.

    1991-01-01

    Micro Channel/Multibus-II interface circuit provides electrical interconnections enabling communications between Micro Channels of IBM Personal System/2 computers and IEEE 1296 standard Multibus-II parallel system bus (iPSB). Made mostly of commercially available parts, interface enables independent Micro Channels to communicate over iPSB without modification.

  18. Spontaneous Calcium Changes in Micro Neuronal Networks

    NASA Astrophysics Data System (ADS)

    Saito, Aki; Moriguchi, Hiroyuki; Iwabuchi, Shin; Goto, Miho; Takayama, Yuzo; Kotani, Kiyoshi; Jimbo, Yasuhiko

    We have developed a practical experimental method to mass-produce and maintain a variation of minimal neuronal networks (“micro neuronal networks”) consisted of a single to several neurons in culture using spray-patterning technique. In this paper, we could maintain the micro-cultures for one month or more by adding conditioned medium and carried out optical recording of spontaneous activity in micro neuronal networks and considered the interactions between them. To determine the interactions between micro neuronal networks, fluorescence changes in several small networks were simultaneously measured using calcium indicator dye fluo-4 AM, and time-series analysis was carried out using surrogate arrangements. By using the spray-patterning method, a large number of cell-adhesive micro regions were formed. Neurons extended neurites along the edge of the cell-adhesive micro regions and form micro neuronal networks. In part of micro regions, some neurite was protruded from the region, and thus micro neuronal networks were connected with synapses. In these networks, a single neuron-induced network activity was observed. On the other hand, even in morphologically non-connected micro neuronal networks, synchronous oscillations between micro neuronal networks were observed. Our micro-patterning methods and results provide the possibility that synchronous activity is occurred between morphologically non-connected neuronal networks. This suggest that the humoral factor is also a important component for network-wide dynamics.

  19. Laboratory 3D Micro-XRF/Micro-CT Imaging System

    NASA Astrophysics Data System (ADS)

    Bruyndonckx, P.; Sasov, A.; Liu, X.

    2011-09-01

    A prototype micro-XRF laboratory system based on pinhole imaging was developed to produce 3D elemental maps. The fluorescence x-rays are detected by a deep-depleted CCD camera operating in photon-counting mode. A charge-clustering algorithm, together with dynamically adjusted exposure times, ensures a correct energy measurement. The XRF component has a spatial resolution of 70 μm and an energy resolution of 180 eV at 6.4 keV. The system is augmented by a micro-CT imaging modality. This is used for attenuation correction of the XRF images and to co-register features in the 3D XRF images with morphological structures visible in the volumetric CT images of the object.

  20. High-Resolution Macromolecular Structure Determination by MicroED, a cryo-EM Method.

    PubMed

    Rodriguez, J A; Gonen, T

    2016-01-01

    Microelectron diffraction (MicroED) is a new cryo-electron microscopy (cryo-EM) method capable of determining macromolecular structures at atomic resolution from vanishingly small 3D crystals. MicroED promises to solve atomic resolution structures from even the tiniest of crystals, less than a few hundred nanometers thick. MicroED complements frontier advances in crystallography and represents part of the rebirth of cryo-EM that is making macromolecular structure determination more accessible for all. Here we review the concept and practice of MicroED, for both the electron microscopist and crystallographer. Where other reviews have addressed specific details of the technique (Hattne et al., 2015; Shi et al., 2016; Shi, Nannenga, Iadanza, & Gonen, 2013), we aim to provide context and highlight important features that should be considered when performing a MicroED experiment.

  1. High-Resolution Macromolecular Structure Determination by MicroED, a cryo-EM Method.

    PubMed

    Rodriguez, J A; Gonen, T

    2016-01-01

    Microelectron diffraction (MicroED) is a new cryo-electron microscopy (cryo-EM) method capable of determining macromolecular structures at atomic resolution from vanishingly small 3D crystals. MicroED promises to solve atomic resolution structures from even the tiniest of crystals, less than a few hundred nanometers thick. MicroED complements frontier advances in crystallography and represents part of the rebirth of cryo-EM that is making macromolecular structure determination more accessible for all. Here we review the concept and practice of MicroED, for both the electron microscopist and crystallographer. Where other reviews have addressed specific details of the technique (Hattne et al., 2015; Shi et al., 2016; Shi, Nannenga, Iadanza, & Gonen, 2013), we aim to provide context and highlight important features that should be considered when performing a MicroED experiment. PMID:27572734

  2. Micro-Tubular Fuel Cells

    NASA Technical Reports Server (NTRS)

    Kimble, Michael C.; Anderson, Everett B.; Jayne, Karen D.; Woodman, Alan S.

    2004-01-01

    Micro-tubular fuel cells that would operate at power levels on the order of hundreds of watts or less are under development as alternatives to batteries in numerous products - portable power tools, cellular telephones, laptop computers, portable television receivers, and small robotic vehicles, to name a few examples. Micro-tubular fuel cells exploit advances in the art of proton-exchange-membrane fuel cells. The main advantage of the micro-tubular fuel cells over the plate-and-frame fuel cells would be higher power densities: Whereas the mass and volume power densities of low-pressure hydrogen-and-oxygen-fuel plate-and-frame fuel cells designed to operate in the targeted power range are typically less than 0.1 W/g and 0.1 kW/L, micro-tubular fuel cells are expected to reach power densities much greater than 1 W/g and 1 kW/L. Because of their higher power densities, micro-tubular fuel cells would be better for powering portable equipment, and would be better suited to applications in which there are requirements for modularity to simplify maintenance or to facilitate scaling to higher power levels. The development of PEMFCs has conventionally focused on producing large stacks of cells that operate at typical power levels >5 kW. The usual approach taken to developing lower-power PEMFCs for applications like those listed above has been to simply shrink the basic plate-and-frame configuration to smaller dimensions. A conventional plate-and-frame fuel cell contains a membrane/electrode assembly in the form of a flat membrane with electrodes of the same active area bonded to both faces. In order to provide reactants to both electrodes, bipolar plates that contain flow passages are placed on both electrodes. The mass and volume overhead of the bipolar plates amounts to about 75 percent of the total mass and volume of a fuel-cell stack. Removing these bipolar plates in the micro-tubular fuel cell significantly increases the power density.

  3. Micro-nano hierarchical superhydrophobic electrospray-synthesized silica layers.

    PubMed

    Kim, Ji-Yeong; Kim, Eun-Kyeong; Kim, Sang Sub

    2013-02-15

    This paper reports the preparation of superhydrophobic SiO(2) layers with a micro-nano hierarchical surface structure. SiO(2) layers, which were rough on the microscale, were prepared using an electrospraying method combined with a sol-gel chemical route. To create a nanoscale structure, the surface of the SiO(2) layers was coated with Au nanoparticles using an ultraviolet-enhanced chemical reduction process, resulting in a micro-nano hierarchical surface structure. A subsequent fluorination treatment with a solution containing trichloro(1H,1H,2H,2H-perfluorooctyl)silane resulted in fluorination of the micro-nano hierarchical SiO(2) layers. The resulting SiO(2) layers showed outstanding repellency toward a range of liquid droplets, for example, a water-repellency of 170°. The surface fraction and work of adhesion of the fluorinated, micro-nano hierarchical SiO(2) layers were estimated using the Cassie-Baxter and Young-Dupre equations, respectively. The long-term durability and ultraviolet resistance of the superhydrophobic SiO(2) layers prepared in this study highlight their potential in a range of practical applications.

  4. Micro- and nanostructured polymer substrates for biomedical applications

    NASA Astrophysics Data System (ADS)

    Althaus, Jasmin; Urwyler, Prabitha; Padeste, Celestino; Heuberger, Roman; Deyhle, Hans; Schift, Helmut; Gobrecht, Jens; Pieles, Uwe; Scharnweber, Dieter; Peters, Kirsten; Müller, Bert

    2012-04-01

    Polymer implants are interesting alternatives to the contemporary load-bearing implants made from metals. Polyetheretherketone (PEEK), a well-established biomaterial for example, is not only iso-elastic to bone but also permits investigating the surrounding soft tissues using magnetic resonance imaging or computed tomography, which is particularly important for cancer patients. The commercially available PEEK bone implants, however, require costly coatings, which restricts their usage. As an alternative to coatings, plasma activation can be applied. The present paper shows the plasma-induced preparation of nanostructures on polymer films and on injection-molded micro-cantilever arrays and the associated chemical modifications of the surface. In vitro cell experiments indicate the suitability of the activation process. In addition, we show that microstructures such as micro-grooves 1 μm deep and 20 μm wide cause cell alignment. The combination of micro-injection molding, simultaneous microstructuring using inserts/bioreplica and plasma treatments permits the preparation of polymer implants with nature-analogue, anisotropic micro- and nanostructures.

  5. MicroRNAs and Epithelial Immunity

    PubMed Central

    Liu, Jun; Drescher, Kristen M.; Chen, Xian-Ming

    2009-01-01

    MicroRNAs are required for development and maintenance of the epithelial barrier. It is hypothesized that microRNAs are involved in regulating epithelial anti-microbial defenses by targeting key epithelial effector molecules and/or influencing intracellular signaling pathways. Additionally, aberrant microRNA expression has been implicated in the pathogenesis of various diseases at the skin and mucosa. Increased understanding of the role of microRNAs in epithelial immunoregulation and identification of microRNAs of pathogenetic significance will enhance our understanding of epithelial immunobiology and immunopathology. PMID:19811319

  6. Impact micro-positioning actuator

    NASA Technical Reports Server (NTRS)

    Cuerden, Brian (Inventor); Angel, J. Roger P. (Inventor); Burge, James H. (Inventor); DeRigne, Scott T. (Inventor)

    2006-01-01

    An impact micro-positioning actuator. In one aspect of the invention, a threaded shaft is threadably received in a nut and the nut is impacted by an impacting device, causing the nut first to rotate relative to the shaft by slipping as a result of shaft inertia and subsequently to stick to the shaft as a result of the frictional force therebetween. The nut is returned to its initial position by a return force provided by a return mechanism after impact. The micro-positioning actuator is further improved by controlling at least one and preferably all of the following: the friction, the impact provided by the impacting device, the return force provided by the return mechanism, and the inertia of the shaft. In another aspect of the invention, a threaded shaft is threadably received in a nut and the shaft is impacted by an impacting device, causing the shaft to rotate relative to the nut.

  7. Modeling and Reconstruction of Micro-structured 3D Chitosan/Gelatin Porous Scaffolds Using Micro-CT

    NASA Astrophysics Data System (ADS)

    Gong, Haibo; Li, Dichen; He, Jiankang; Liu, Yaxiong; Lian, Qin; Zhao, Jinna

    2008-09-01

    Three dimensional (3D) channel networks are the key to promise the uniform distribution of nutrients inside 3D hepatic tissue engineering scaffolds and prompt elimination of metabolic products out of the scaffolds. 3D chitosan/gelatin porous scaffolds with predefined internal channels were fabricated and a combination of light microscope, laser confocal microscopy and micro-CT were employed to characterize the structure of porous scaffolds. In order to evaluate the flow field distribution inside the micro-structured 3D scaffolds, a computer reconstructing method based on Micro-CT was proposed. According to this evaluating method, a contrast between 3D porous scaffolds with and without predefined internal channels was also performed to assess scaffolds' fluid characters. Results showed that the internal channel of the 3D scaffolds formed the 3D fluid channel network; the uniformity of flow field distribution of the scaffolds fabricated in this paper was better than the simple porous scaffold without micro-fluid channels.

  8. Micro-optofluidic Lenses: A review

    PubMed Central

    Nguyen, Nam-Trung

    2010-01-01

    This review presents a systematic perspective on the development of micro-optofluidic lenses. The progress on the development of micro-optofluidic lenses are illustrated by example from recent literature. The advantage of micro-optofluidic lenses over solid lens systems is their tunability without the use of large actuators such as servo motors. Depending on the relative orientation of light path and the substrate surface, micro-optofluidic lenses can be categorized as in-plane or out-of-plane lenses. However, this review will focus on the tunability of the lenses and categorizes them according to the concept of tunability. Micro-optofluidic lenses can be either tuned by the liquid in use or by the shape of the lens. Micro-optofluidic lenses with tunable shape are categorized according to the actuation schemes. Typical parameters of micro-optofluidic lenses reported recently are compared and discussed. Finally, perspectives are given for future works in this field. PMID:20714369

  9. Human polarimetric micro-doppler

    NASA Astrophysics Data System (ADS)

    Tahmoush, David; Silvious, Jerry

    2011-06-01

    Modern radars can pick up target motions other than just the principle target Doppler; they pick out the small micro-Doppler variations as well. These can be used to visually identify both the target type as well as the target activity. We model and measure some of the micro-Doppler motions that are amenable to polarimetric measurement. Understanding the capabilities and limitations of radar systems that utilize micro-Doppler to measure human characteristics is important for improving the effectiveness of these systems at securing areas. In security applications one would like to observe humans unobtrusively and without privacy issues, which make radar an effective approach. In this paper we focus on the characteristics of radar systems designed for the estimation of human motion for the determination of whether someone is loaded. Radar can be used to measure the direction, distance, and radial velocity of a walking person as a function of time. Detailed radar processing can reveal more characteristics of the walking human. The parts of the human body do not move with constant radial velocity; the small micro-Doppler signatures are timevarying and therefore analysis techniques can be used to obtain more characteristics. Looking for modulations of the radar return from arms, legs, and even body sway are being assessed by researchers. We analyze these techniques and focus on the improved performance that fully polarimetric radar techniques can add. We perform simulations and fully polarimetric measurements of the varying micro-Doppler signatures of humans as a function of elevation angle and azimuthal angle in order to try to optimize this type of system for the detection of arm motion, especially for the determination of whether someone is carrying something in their arms. The arm is often bent at the elbow, providing a surface similar to a dihedral. This is distinct from the more planar surfaces of the body and allows us to separate the signals from the arm (and

  10. Comparison of 4D-microSPECT and microCT for murine cardiac function

    PubMed Central

    Befera, Nicholas T.; Badea, Cristian T.; Johnson, G. Allan

    2014-01-01

    Purpose The objective of this study was to compare a new generation of four-dimensional (4D) microSPECT with microCT for quantitative in vivo assessment of murine cardiac function. Procedures 4D isotropic cardiac images were acquired from normal C57BL/6 mice with either microSPECT at 350-micron resolution (n=6) or microCT at 88-micron resolution (n=6). One additional mouse with myocardial infarction (MI) was scanned with both modalities. Prior to imaging, mice were injected with either 99mTc -tetrofosmin for microSPECT, or a liposomal blood pool contrast agent for microCT. Segmentation of the left ventricle (LV) was performed using Vitrea (Vital Images) software, to derive global and regional function. Results Measures of global LV function between microSPECT and microCT groups were comparable (e.g. ejection fraction=71±6%-microSPECT and 68±4%-microCT). Regional functional indices (wall motion, wall thickening, regional ejection fraction) were also similar for the two modalities. In the mouse with MI, microSPECT identified a large perfusion defect that was not evident with microCT. Conclusions Despite lower spatial resolution, microSPECT was comparable to microCT in the quantitative evaluation of cardiac function. MicroSPECT offers an advantage over microCT in the ability to evaluate myocardial perfusion radiotracer distribution and function simultaneously. MicroSPECT should be considered as an alternative to microCT and MR for preclinical cardiac imaging in the mouse. PMID:24037175

  11. Sensitivity Jump of Micro Accelerometer Induced by Micro-fabrication Defects of Micro Folded Beams

    NASA Astrophysics Data System (ADS)

    Zhou, Wu; Chen, Lili; Yu, Huijun; Peng, Bei; Chen, Yu

    2016-08-01

    The abnormal phenomenon occurring in sensor calibration is an obstacle to product development but a useful guideline to product improvement. The sensitivity jump of micro accelerometers in the calibrating process is recognized as an important abnormal behavior and investigated in this paper. The characteristics of jumping output in the centrifuge test are theoretically and experimentally analyzed and their underlying mechanism is found to be related to the varied stiffness of supporting beam induced by the convex defect on it. The convex defect is normally formed by the lithography deviation and/or etching error and can result in a jumping stiffness of folded microbeams and further influence the sensitivity when a part of the bending beams is stopped from moving by two surfaces contacting. The jumping level depends on the location of convex and has nothing to do with the contacting properties of beam and defects. Then the location of defect is predicted by theoretical model and simulation and verified by the observation of micro structures under microscopy. The results indicate that the tested micro accelerometer has its defect on the beam with a distance of about 290μm from the border of proof mass block.

  12. Stirling engines for gas fired micro-cogen and cooling

    SciTech Connect

    Lane, N.W.; Beale, W.T.

    1996-12-31

    This paper describes the design and performance of free-piston Stirling engine-alternators particularly suited for use as natural gas fired micro-cogen and cooling devices. Stirling based cogen systems offer significant potential advantages over internal combustion engines in efficiency, to maintain higher efficiencies at lower power levels than than combustion engines significantly expands the potential for micro-cogen. System cost reduction and electric prices higher than the U.S. national average will have a far greater effect on commercial success than any further increase in Stirling engine efficiency. There exist niche markets where Stirling engine efficiency. There exist niche markets where Stirling based cogen systems are competitive. Machines of this design are being considered for production in the near future as gas-fired units for combined heat and power in sufficiently large quantities to assure competitive prices for the final unit.

  13. MicroRNAs in obesity-associated disorders.

    PubMed

    Abente, Eugenio J; Subramanian, Murugan; Ramachandran, Vimal; Najafi-Shoushtari, S Hani

    2016-01-01

    The emergence of a worldwide obesity epidemic has dramatically increased the prevalence of insulin resistance and metabolic syndrome, predisposing individuals to a greater risk for the development of non-alcoholic fatty liver disease, type II diabetes and atherosclerotic cardiovascular diseases. Current available pharmacological interventions combined with diet and exercise-based managements are still poorly effective for weight management, likely in part due to an incomplete understanding of regulatory mechanisms and pathways contributing to the systemic metabolic abnormalities under disturbed energy homeostasis. MicroRNAs, small non-coding RNAs that regulate posttranscriptional gene expression, have been increasingly described to influence shifts in metabolic pathways under various obesity-related disease settings. Here we review recent discoveries of the mechanistic role that microRNAs play in regulating metabolic functions in liver and adipose tissues involved in obesity associated disorders, and briefly discusses the potential candidates that are being pursued as viable therapeutic targets.

  14. Self-assembly 'micro-origami' photon cages as hollow micro-resonators

    NASA Astrophysics Data System (ADS)

    Danescu, A.; Chevalier, C.; Artinyan, R.; Regreny, P.; Grenet, G.; Callard, S.; Rojo-Romeo, P.; Letartre, X.; Leclercq, J. L.

    2015-06-01

    Selective etching of pre-stressed multi-layered structures releases intrinsic stresses creating flexible macroscopic shapes (rolls, spirals, tubes…). Combining mechanical and photonic concepts, we develop an experimental approach by controlling material composition, mask design and etching process in order to obtain prescribed macroscopic 3D hollow optical micro-cavities. New photonic microstructures are proposed for an efficient light trapping in low index media. Cylindrical hollow cavities formed by bending a photonic crystal membrane are designed. Using numerical simulations, strong confinement of photons is demonstrated for very open resonators. The resulting strong light matter interaction can be exploited in optical devices comprising an active material embedded in a low index matrix like polymer or even gaz.

  15. In vitro synchrotron-based radiography of micro-gap formation at the implant–abutment interface of two-piece dental implants

    PubMed Central

    Rack, A.; Rack, T.; Stiller, M.; Riesemeier, H.; Zabler, S.; Nelson, K.

    2010-01-01

    Micro-gap formation at the implant–abutment interface of two-piece dental implants was investigated in vitro using high-resolution radiography in combination with hard X-ray synchrotron radiation. Images were taken with the specimen under different mechanical loads of up to 100 N. The aim of this investigation was to prove the existence of micro-gaps for implants with conical connections as well as to study the mechanical behavior of the mating zone of conical implants during loading. Synchrotron-based radiography in comparison with classical laboratory radiography yields high spatial resolution in combination with high contrast even when exploiting micro-sized features in highly attenuating objects. The first illustration of a micro-gap which was previously indistinguishable by laboratory methods underlines that the complex micro-mechanical behavior of implants requires further in vitro investigations where synchrotron-based micro-imaging is one of the prerequisites. PMID:20157285

  16. MicroRNAs in cancer: from developmental genes in worms to their clinical application in patients

    PubMed Central

    Pichler, M; Calin, G A

    2015-01-01

    Several discoveries have paved the way to personalise cancer medicine and a tremendous gain of knowledge in genomics and molecular mechanisms of cancer progression cumulated over the last years. Big stories in biology commonly start in a simple model system. No wonder microRNAs have been identified as regulators of embryonic development in the nematode Caenorhabditis elegans. From the first identification in worms to the first-in-man microRNA-based clinical trial in humans, almost 20 years passed. In this review we follow the story of understanding microRNA alterations in cancer, describe recent developments in the microRNA field and critically discuss their potential as diagnostic, prognostic and therapeutics factors in cancer medicine. We will explain the rationale behind the use of microRNAs in cancer diagnosis and prognosis prediction, but also discuss the limitations and pitfalls associated with this. Novel developments of combined microRNA/siRNA pharmacological approaches will be discussed and most recently data about MXR34, the first-tested microRNA drug will be described. PMID:26158421

  17. MicroRNA-regulated pathways in hematological malignancies: how to avoid cells playing out of tune.

    PubMed

    Fatica, Alessandro; Fazi, Francesco

    2013-01-01

    The coordinated expression and interplay among lineage specific transcription factors and microRNAs contribute to the regulation of gene expression and determination of cell specificity. In hematopoietic stem cells (HSCs), unique combinations of transcription factors largely control growth and maturation of different blood cell lineages through cooperative regulation of specific target genes. MicroRNAs provide an additional level of control beyond transcription factors. By acting as regulators of crucial lineage-specific genetic programs, microRNAs direct early multipotential progenitor cells to adopt a certain cell fate program. Thus, alteration of specific microRNA levels may affect proliferation, differentiation and genetic stability of HSCs, contributing to the onset of myeloproliferative disorders and leukemia. The major aim of this review is to highlight the critical role of microRNA-regulated pathways during the establishment and progression of hematological malignancies, with a particular attention to leukemia, lymphomas and myelodysplastic syndromes. This will give us the opportunity to discuss the potential use of microRNA-based therapeutic approaches in these diseases. MicroRNAs are indeed emerging as relevant tools to improve the efficacy of currently used therapeutic protocols.

  18. Robust monolithic silica-based on-chip electro-osmotic micro-pump.

    PubMed

    Nie, Fu-Qiang; Macka, Mirek; Barron, Leon; Connolly, Damian; Kent, Nigel; Paull, Brett

    2007-05-01

    A robust, compact, on-chip, electro-osmotic micro-pump (EOP) for micro-flow analysis, based on parallel, encased, 10 x 0.1 mm I.D. monolithic silica capillary columns has been developed. A 15 x 40 x 2 mm poly(methyl methacrylate) (PMMA) chip, containing a total of nine parallel EOP systems was fabricated, allowing the use of single, double or triple monolithic columns to produce increased flow as required. The monolithic silica was compatible with both aqueous and organic solvents without swelling or shrinking problems, with the triple column EOP capable of generating flow of up to 0.6 microL min(-1) under zero pressure load and over 0.1 microL min(-1) with an applied pressure of ca. 2.4 bar using an applied voltage of just 2 kV. Current generated at the 2 kV applied voltage for a 2 mM acetate buffer solution (pH 4.5) was under 4 microA, allowing stable, bubble-free flow. The developed triple column EOP was incorporated within a micro-fluidic chip (5.0 x 2.0 x 0.4 cm) integrated with a second single 10 x 0.1 mm column EOP, for combined sample injection and simple on-chip micro-flow analysis.

  19. Comparison between micro-Raman and micro-FTIR spectroscopy techniques for the characterization of pigments from Southern Spain Cultural Heritage

    NASA Astrophysics Data System (ADS)

    Franquelo, M. L.; Duran, A.; Herrera, L. K.; Jimenez de Haro, M. C.; Perez-Rodriguez, J. L.

    2009-04-01

    An extensive overview of the complementary use of micro-FTIR and micro-Raman spectroscopy in the Cultural Heritage studies is described in this work. The samples have been prepared using the cross-section technique. This technique allows the examination of a large portion of a single paint layer in its original condition. A variety of pigments from samples belonging principally to the Cultural Heritage of Southern Spain were characterized by micro-Raman spectroscopy using visible excitation sources and micro-FTIR spectroscopy. The pigments studied comprise blue (azurite, ultramarine blue, Prussian blue), red (vermilion, haematite, red ochre, red lead, etc.), ochre and yellow (goethite, orpiment, realgar, etc.), green (malachite, copper resinate), and white (calcite, gypsum, white lead, titanium white, barite, lithopone) pigments, among others. An orientation is given for their appropriate and unequivocal characterization. Characterization by micro-FTIR and micro-Raman presents difficulties with some pigments. In these cases, analysis by EDX solves most of these doubts. The combined use of both spectroscopic techniques, together with SEM-EDX microanalysis, provides one of the most useful methods in the characterization (and possible dating) of materials used in Cultural Heritage.

  20. Large-scale profiling of microRNAs for The Cancer Genome Atlas

    PubMed Central

    Chu, Andy; Robertson, Gordon; Brooks, Denise; Mungall, Andrew J.; Birol, Inanc; Coope, Robin; Ma, Yussanne; Jones, Steven; Marra, Marco A.

    2016-01-01

    The comprehensive multiplatform genomics data generated by The Cancer Genome Atlas (TCGA) Research Network is an enabling resource for cancer research. It includes an unprecedented amount of microRNA sequence data: ∼11 000 libraries across 33 cancer types. Combined with initiatives like the National Cancer Institute Genomics Cloud Pilots, such data resources will make intensive analysis of large-scale cancer genomics data widely accessible. To support such initiatives, and to enable comparison of TCGA microRNA data to data from other projects, we describe the process that we developed and used to generate the microRNA sequence data, from library construction through to submission of data to repositories. In the context of this process, we describe the computational pipeline that we used to characterize microRNA expression across large patient cohorts. PMID:26271990

  1. Large-scale profiling of microRNAs for The Cancer Genome Atlas.

    PubMed

    Chu, Andy; Robertson, Gordon; Brooks, Denise; Mungall, Andrew J; Birol, Inanc; Coope, Robin; Ma, Yussanne; Jones, Steven; Marra, Marco A

    2016-01-01

    The comprehensive multiplatform genomics data generated by The Cancer Genome Atlas (TCGA) Research Network is an enabling resource for cancer research. It includes an unprecedented amount of microRNA sequence data: ~11 000 libraries across 33 cancer types. Combined with initiatives like the National Cancer Institute Genomics Cloud Pilots, such data resources will make intensive analysis of large-scale cancer genomics data widely accessible. To support such initiatives, and to enable comparison of TCGA microRNA data to data from other projects, we describe the process that we developed and used to generate the microRNA sequence data, from library construction through to submission of data to repositories. In the context of this process, we describe the computational pipeline that we used to characterize microRNA expression across large patient cohorts.

  2. Geometric calibration of a micro-CT system and performance for insect imaging.

    PubMed

    Hu, Zhanli; Gui, Jianbao; Zou, Jing; Rong, Junyan; Zhang, Qiyang; Zheng, Hairong; Xia, Dan

    2011-07-01

    Micro-CT with a high spatial resolution in combination with computer-based-reconstruction techniques is considered a powerful tool for morphological study of insects. The quality of CT images crucially depends on the precise knowledge of the scan geometry of the micro-CT system. In this paper, we have proposed a method to calculate the deviation of rotating axis for compensating deficiency of existing methods. A practical application of this geometric calibration method of the micro-CT system for insect imaging is presented. We have performed the computer-simulation study and experimental study with our prototype micro-CT system. The results demonstrate that the proposed technique is accurate and robust. In addition, we have evaluated the imaging characteristics of the detector in terms of modulation-transfer function (MTF). Finally, insect imaging performance and image reconstruction from data acquired with different energies are presented.

  3. microRNAs and Endometrial Pathophysiology.

    PubMed

    Chill, Henry H; Dior, Uri P; Kogan, Liron; Revel, Ariel

    2015-01-01

    Embryo implantation requires a reciprocal interaction between the blastocyst and endometrium and is associated with complex regulatory mechanisms. Since their discovery, microRNAs became prominent candidates providing missing links for many biological pathways. In recent years, microRNAs were implicated as one of the important players in regulation of various biological and physiological endometrial related processes. This chapter aims to present recent knowledge pertaining to the diverse aspects of microRNAs in the embryo-endometrial relationship. We will focus on the role of microRNAs in decidualization and their part in natural and stimulated cycles. Next, we will present recent studies deliberating the role of microRNAs in recurrent pregnancy loss and in the important phenomenon of recurrent implantation failure. Lastly, demonstrating an important aspect of embryo implantation and invasion, we will outline few microRNA related shared pathways of implantation and carcinogenesis. PMID:26662990

  4. Micro Bubble Trapping By Acoustic Energy

    NASA Astrophysics Data System (ADS)

    Yoshiki, Yamakoshi

    2005-03-01

    Micro bubble trapping by acoustic energy is a promising technology for a future drug or gene delivery system, because the method can control the bubble dynamics using an applied ultrasonic wave. In this paper, acoustic radiation forces which are applied to the micro bubbles are reviewed as well as their applications for micro bubble manipulation. One of the problems in micro bubble trapping by acoustic energy is that the force applied to the micro bubbles is insufficient for some bubbles. This is severe problem when the bubble has a relatively hard shell. In order to increase the trapping force on the micro bubbles, a novel method is proposed. This method uses seed bubbles in order to manipulate target bubbles.

  5. Micro-unmanned aerodynamic vehicle

    DOEpatents

    Reuel, Nigel; Lionberger, Troy A.; Galambos, Paul C.; Okandan, Murat; Baker, Michael S.

    2008-03-11

    A MEMS-based micro-unmanned vehicle includes at least a pair of wings having leading wing beams and trailing wing beams, at least two actuators, a leading actuator beam coupled to the leading wing beams, a trailing actuator beam coupled to the trailing wing beams, a vehicle body having a plurality of fulcrums pivotally securing the leading wing beams, the trailing wing beams, the leading actuator beam and the trailing actuator beam and having at least one anisotropically etched recess to accommodate a lever-fulcrum motion of the coupled beams, and a power source.

  6. Chemically powered micro- and nanomotors.

    PubMed

    Sánchez, Samuel; Soler, Lluís; Katuri, Jaideep

    2015-01-26

    Chemically powered micro- and nanomotors are small devices that are self-propelled by catalytic reactions in fluids. Taking inspiration from biomotors, scientists are aiming to find the best architecture for self-propulsion, understand the mechanisms of motion, and develop accurate control over the motion. Remotely guided nanomotors can transport cargo to desired targets, drill into biomaterials, sense their environment, mix or pump fluids, and clean polluted water. This Review summarizes the major advances in the growing field of catalytic nanomotors, which started ten years ago.

  7. Chemically powered micro- and nanomotors.

    PubMed

    Sánchez, Samuel; Soler, Lluís; Katuri, Jaideep

    2015-01-26

    Chemically powered micro- and nanomotors are small devices that are self-propelled by catalytic reactions in fluids. Taking inspiration from biomotors, scientists are aiming to find the best architecture for self-propulsion, understand the mechanisms of motion, and develop accurate control over the motion. Remotely guided nanomotors can transport cargo to desired targets, drill into biomaterials, sense their environment, mix or pump fluids, and clean polluted water. This Review summarizes the major advances in the growing field of catalytic nanomotors, which started ten years ago. PMID:25504117

  8. Injection molding and debinding of micro gears fabricated by micro powder injection molding

    NASA Astrophysics Data System (ADS)

    Ni, Xin-lei; Yin, Hai-qing; Liu, Lin; Yi, Shan-jie; Qu, Xuan-hui

    2013-01-01

    Micro powder injection molding (μPIM) was investigated for possible mass production of micro-components at relatively low cost. However, scaling down to such a level produces challenges in injection molding and debinding. Micro gears were fabricated by μPIM from in-house feedstock. The effect of injection speed and injection pressure on the replication of the micro gear cavity was investigated. Solvent debinding and thermal debinding processes were discussed. The results show that micro gears can be successfully fabricated under the injection pressure of 70 MPa and the 60% injection speed. Either too low or too high injection speed can cause incomplete filling of micro gears. The same is the case with too low injection pressure. Too high injection pressure can bring cracks. Solvent debinding of micro gears was performed in a mixture of petroleum ether and ethanol. Subsequently, micro gears were successfully debound by a multistep heating schedule.

  9. Assembly planning at the micro scale

    SciTech Connect

    Feddema, J.T.; Xavier, P.; Brown, R.

    1998-05-14

    This paper investigates a new aspect of fine motion planning for the micro domain. As parts approach 1--10 {micro}m or less in outside dimensions, interactive forces such as van der Waals and electrostatic forces become major factors which greatly change the assembly sequence and path plans. It has been experimentally shown that assembly plans in the micro domain are not reversible, motions required to pick up a part are not the reverse of motions required to release a part. This paper develops the mathematics required to determine the goal regions for pick up, holding, and release of a micro-sphere being handled by a rectangular tool.

  10. Telomerase Reverse Transcriptase Regulates microRNAs

    PubMed Central

    Lassmann, Timo; Maida, Yoshiko; Tomaru, Yasuhiro; Yasukawa, Mami; Ando, Yoshinari; Kojima, Miki; Kasim, Vivi; Simon, Christophe; Daub, Carsten O.; Carninci, Piero; Hayashizaki, Yoshihide; Masutomi, Kenkichi

    2015-01-01

    MicroRNAs are small non-coding RNAs that inhibit the translation of target mRNAs. In humans, most microRNAs are transcribed by RNA polymerase II as long primary transcripts and processed by sequential cleavage of the two RNase III enzymes, DROSHA and DICER, into precursor and mature microRNAs, respectively. Although the fundamental functions of microRNAs in RNA silencing have been gradually uncovered, less is known about the regulatory mechanisms of microRNA expression. Here, we report that telomerase reverse transcriptase (TERT) extensively affects the expression levels of mature microRNAs. Deep sequencing-based screens of short RNA populations revealed that the suppression of TERT resulted in the downregulation of microRNAs expressed in THP-1 cells and HeLa cells. Primary and precursor microRNA levels were also reduced under the suppression of TERT. Similar results were obtained with the suppression of either BRG1 (also called SMARCA4) or nucleostemin, which are proteins interacting with TERT and functioning beyond telomeres. These results suggest that TERT regulates microRNAs at the very early phases in their biogenesis, presumably through non-telomerase mechanism(s). PMID:25569094

  11. Turbo Pump Fed Micro-Rocket Engine

    NASA Astrophysics Data System (ADS)

    Miotti, P.; Tajmar, M.; Seco, F.; Guraya, C.; Perennes, F.; Soldati, A.; Lang, M.

    2004-10-01

    Micro-satellites (from 10kg up to 100kg) have mass, volume, and electrical power constraints due to their low dimensions. These limitations lead to the lack in currently available active orbit control systems in micro-satellites. Therefore, a micro-propulsion system with a high thrust to mass ratio is required to increase the potential functionality of small satellites. Mechatronic is presently working on a liquid bipropellant micro-rocket engine under contract with ESA (Contract No.16914/NL/Sfe - Micro-turbo-machinery Based Bipropellant System Using MNT). The advances in Mechatronic's project are to realise a micro-rocket engine with propellants pressurised by micro-pumps. The energy for driving the pumps would be extracted from a micro-turbine. Cooling channels around the nozzle would be also used in order to maintain the wall material below its maximum operating temperature. A mass budget comparison with more traditional pressure-fed micro-rockets shows a real benefit from this system in terms of mass reduction. In the paper, an overview of the project status in Mechatronic is presented.

  12. A mechanical micro molecular mass sensor

    PubMed Central

    Kurhekar, A. S.; Apte, P. R.

    2014-01-01

    One of the bio-sensing mechanisms is mechanical. Rather than measuring shift in resonance frequency, we adopt to measure the change in spring constant due to adsorption, as one of the fundamental sensing mechanism. This study explains determination of spring constant of a surface functionalized micro machined micro cantilever, which resonates in a trapezoidal cavity-on Silicon <100> wafer, with the resonating frequency of 7000 cycles per second. This thin-flimsy-oxide micro-cantilever has a typical shape, and the tip of the micro-cantilever is dip-coated with chemically and biologically active material. The change in mass, due to adsorption, is detected by measuring the change in spring constant. The Force-Distance spectroscopy is used to detect the change in spring constant. The experimental results, show that the mechanical sensing scheme used, permit this surface functionalized micro machined micro cantilever to be used as a molecular mass sensor. The mechanical spring behaviour of a micro-cantilever, a micro-mechanical device can be used to develop ultra-tech micro-mechanical system using computer interface. PMID:24459585

  13. Stretchable Micro-Electrode Array

    SciTech Connect

    Maghribi, M; Hamilton, J; Polla, D; Rose, K; Wilson, T; Krulevitch, P

    2002-03-08

    This paper focuses on the design consideration, fabrication processes and preliminary testing of the stretchable micro-electrode array. We are developing an implantable, stretchable micro-electrode array using polymer-based microfabrication techniques. The device will serve as the interface between an electronic imaging system and the human eye, directly stimulating retinal neurons via thin film conducting traces and electroplated electrodes. The metal features are embedded within a thin ({approx}50 micron) substrate fabricated using poly (dimethylsiloxane) (PDMS), a biocompatible elastomeric material that has very low water permeability. The conformable nature of PDMS is critical for ensuring uniform contact with the curved surface of the retina. To fabricate the device, we developed unique processes for metalizing PDMS to produce robust traces capable of maintaining conductivity when stretched (5%, SD 1.5), and for selectively passivating the conductive elements. An in situ measurement of residual strain in the PDMS during curing reveals a tensile strain of 10%, explaining the stretchable nature of the thin metalized devices.

  14. microRNA: Diagnostic Perspective

    PubMed Central

    Faruq, Omar; Vecchione, Andrea

    2015-01-01

    Biomarkers are biological measures of a biological state. An ideal marker should be safe and easy to measure, cost efficient, modifiable with treatment, and consistent across gender and ethnic groups. To date, none of the available biomarkers satisfy all of these criteria. In addition, the major limitations of these markers are low specificity, sensitivity, and false positive results. Recently identified, microRNAs (miRNAs) are endogenous, evolutionarily conserved small non-coding RNA (about 22–25 nt long), also known as micro-coordinators of gene expression, which have been shown to be an effective tools to study the biology of diseases and to have great potential as novel diagnostic and prognostic biomarkers with high specificity and sensitivity. In fact, it has been demonstrated that miRNAs play a pivotal role in the regulation of a wide range of developmental and physiological processes and their deficiencies have been related to a number of disease. In addition, miRNAs are stable and can be easily isolated and measured from tissues and body fluids. In this review, we provide a perspective on emerging concepts and potential usefulness of miRNAs as diagnostic markers, emphasizing the involvement of specific miRNAs in particular tumor types, subtypes, cardiovascular diseases, diabetes, infectious diseases, and forensic test. PMID:26284247

  15. Design of an optical system with large depth of field using in the micro-assembly

    NASA Astrophysics Data System (ADS)

    Li, Rong; Chang, Jun; Zhang, Zhi-jing; Ye, Xin; Zheng, Hai-jing

    2013-08-01

    Micro system currently is the mainstream of application and demand of the field of micro fabrication of civilian and national defense. Compared with the macro assembly, the requirements on location accuracy of the micro-assembly system are much higher. Usually the dimensions of the components of the micro-assembly are mostly between a few microns to several hundred microns. The general assembly precision requires for the sub-micron level. Micro system assembly is the bottleneck of micro fabrication currently. The optical stereo microscope used in the field of micro assembly technology can achieve high-resolution imaging, but the depth of field of the optical imaging system is too small. Thus it's not conducive to the three-dimensional observation process of the micro-assembly. This paper summarizes the development of micro system assembly at home and abroad firstly. Based on the study of the core features of the technology, a program is proposed which uses wave front coding technology to increase the depth of field of the optical imaging system. In the wave front coding technology, by combining traditional optical design with digital image processing creatively, the depth of field can be greatly increased, moreover, all defocus-related aberrations, such as spherical aberration, chromatic aberration, astigmatism, Ptzvel(field) curvature, distortion, and other defocus induced by the error of assembling and temperature change, can be corrected or minimized. In this paper, based on the study of theory, a set of optical microscopy imaging system is designed. This system is designed and optimized by optical design software CODE V and ZEMAX. At last, the imaging results of the traditional optical stereo microscope and the optical stereo microscope applied wave front coding technology are compared. The results show that: the method has a practical operability and the phase plate obtained by optimized has a good effect on improving the imaging quality and increasing the

  16. Circulating microRNAs in Neurodegenerative Diseases.

    PubMed

    Grasso, Margherita; Piscopo, Paola; Crestini, Alessio; Confaloni, Annamaria; Denti, Michela A

    2015-01-01

    Neurodegenerative diseases, such as Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS), are caused by a combination of events that impair normal neuronal function. Although they are considered different disorders, there are overlapping features among them from the clinical, pathological, and genetic points of view. Synaptic dysfunction and loss, neurite retraction, and the appearance of other abnormalities such as axonal transport defects normally precede the neuronal loss that is a relatively late event. The diagnosis of many neurodegenerative diseases is mainly based on patient's cognitive function analysis, and the development of diagnostic methods is complicated by the brain's capacity to compensate for neuronal loss over a long period of time. This results in the late clinical manifestation of symptoms, a time when successful treatment is no longer feasible. Thus, a noninvasive diagnostic method based on early events detection is particularly important. In the last years, some biomarkers expressed in human body fluids have been proposed. microRNAs (miRNAs), with their high stability, tissue- or cell type-specific expression, lower cost, and shorter time in the assay development, could constitute a good tool to obtain an early disease diagnosis for a wide number of human pathologies, including neurodegenerative diseases. The possibilities and challenges of using these small RNA molecules as a signature for neurodegenerative disorders is a highly promising approach for developing minimally invasive screening tests and to identify new therapeutic targets.

  17. Virus-encoded microRNAs

    PubMed Central

    Grundhoff, Adam; Sullivan, Christopher S.

    2011-01-01

    microRNAs (miRNAs) are the subject of enormous interest. They are small non-coding RNAs that play a regulatory role in numerous and diverse cellular processes such as immune function, apoptosis and tumorigenesis. Several virus families have been shown to encode miRNAs, and an appreciation for their roles in the viral infectious cycle continues to grow. Despite the identification of numerous (>225) viral miRNAs, an in depth functional understanding of most virus-encoded miRNAs is lacking. Here we focus on a few viral miRNAs with well-defined functions. We use these examples to extrapolate general themes of viral miRNA activities including autoregulation of gene expression, avoidance of host defenses, and a likely important role in maintaining latent and persistent infections. We hypothesize that although the molecular mechanisms and machinery are similar, the majority of viral miRNAs may utilize a target strategy that differs from host miRNAs. That is, many viral miRNAs may have evolved to regulate viral-encoded transcripts or networks of host genes that are unique to viral miRNAs. Included in this latter category are a likely abundant class of viral miRNAs that may regulate only one or a few principal host genes. Key steps forward for the field are discussed, including the need for additional functional studies that utilize surgical viral miRNA mutants combined with relevant models of infection. PMID:21277611

  18. MicroRNAs and cardiac regeneration

    PubMed Central

    Hodgkinson, Conrad P.; Kang, Martin H.; Dal-Pra, Sophie; Mirotsou, Maria; Dzau, Victor J.

    2015-01-01

    The human heart has a very limited capacity to regenerate lost or damaged cardiomyocytes following cardiac insult. Instead, myocardial injury is characterized by extensive cardiac remodeling by fibroblasts, resulting in the eventual deterioration of cardiac structure and function. Cardiac function would be improved if these fibroblasts could be converted into cardiomyocytes. MicroRNAs (miRNAs), small non-coding RNAs that promote mRNA degradation and inhibit mRNA translation, have been shown to be important in cardiac development. Using this information various researchers have utilized miRNAs to promote the formation of cardiomyocytes through a number of approaches. Several miRNAs acting in combination promote the direct conversion of cardiac fibroblasts into cardiomyocytes. Moreover, a number of miRNAs have been identified that aid the formation of iPS cells and miRNAs also induce these cells to adopt a cardiac fate. MiRNAs have also been implicated in resident cardiac progenitor cell differentiation. In this review we will discuss the current literature as it pertains to these processes as well as discussing the therapeutic implications of these findings. PMID:25953925

  19. Micro Electron MicroProbe and Sample Analyzer

    NASA Technical Reports Server (NTRS)

    Manohara, Harish; Bearman, Gregory; Douglas, Susanne; Bronikowski, Michael; Urgiles, Eduardo; Kowalczyk, Robert; Bryson, Charles

    2009-01-01

    A proposed, low-power, backpack-sized instrument, denoted the micro electron microprobe and sample analyzer (MEMSA), would serve as a means of rapidly performing high-resolution microscopy and energy-dispersive x-ray spectroscopy (EDX) of soil, dust, and rock particles in the field. The MEMSA would be similar to an environmental scanning electron microscope (ESEM) but would be much smaller and designed specifically for field use in studying effects of geological alteration at the micrometer scale. Like an ESEM, the MEMSA could be used to examine uncoated, electrically nonconductive specimens. In addition to the difference in size, other significant differences between the MEMSA and an ESEM lie in the mode of scanning and the nature of the electron source.

  20. Aging characteristics of blue InGaN micro-light emitting diodes at an extremely high current density of 3.5 kA cm-2

    NASA Astrophysics Data System (ADS)

    Tian, Pengfei; Althumali, Ahmad; Gu, Erdan; Watson, Ian M.; Dawson, Martin D.; Liu, Ran

    2016-04-01

    The aging characteristics of blue InGaN micro-light emitting diodes (micro-LEDs) with different sizes have been studied at an extremely high current density 3.5 kA cm-2 for emerging micro-LED applications including visible light communication (VLC), micro-LED pumped organic lasers and optogenetics. The light output power of micro-LEDs first increases and then decreases due to the competition of Mg activation in p-GaN layer and defect generation in the active region. The smaller micro-LEDs show less light output power degradation compared with larger micro-LEDs, which is attributed to the lower junction temperature of smaller micro-LEDs. It is found that the high current density without additional junction temperature cannot induce significant micro-LED degradation at room temperature but the combination of the high current density and high junction temperature leads to strong degradation. Furthermore, the cluster LEDs, composed of a micro-LED array, have been developed with both high light output power and less light output degradation for micro-LED applications in solid state lighting and VLC.

  1. Supernova Remnant Observations with Micro-X

    NASA Astrophysics Data System (ADS)

    Figueroa, Enectali

    Micro-X is a sounding rocket payload that combines an X-ray microcalorimeter with an imaging mirror to offer breakthrough science from high spectral resolution observations of extended X-ray sources. This payload has been in design and development for the last five years and is now completely built and undergoing integration; its first flight will be in November, 2012, as part of our current NASA award. This four-year follow-on proposal seeks funding for: (1) analysis of the first flight data, (2) the second flight and its data analysis, (3) development of payload upgrades and launch of the third flight, and (4) third flight data analysis. The scientific payload consists of a Transition Edge Sensor (TES) microcalorimeter array at the focus of a flight-proven conical imaging mirror. Micro-X capitalizes on three decades of NASA investment in the development of microcalorimeters and X-ray imaging optics. Micro-X offers a unique combination of bandpass, collecting area, and spectral and angular resolution. The spectral resolution goal across the 0.2 - 3.0 keV band is 2 - 4 eV Full-Width at Half Maximum (FWHM). The measured angular resolution of the mirror is 2.4 arcminute Half-Power Diameter (HPD). The effective area of the mirror, 300 square centimeters at 1 keV, is sufficient to provide observations of unprecedented quality of several astrophysical X-ray sources, even in a brief sounding rocket exposure of 300 sec. Our scientific program for this proposal will focus on supernova remnants (SNRs), whose spatial extent has made high-energy resolution observations with grating instruments extremely challenging. X-ray observations of SNRs with microcalorimeters will enable the study of the detailed atomic physics of the plasma; the determination of temperature, turbulence, and elemental abundances; and in conjunction with historical data, full three dimensional mapping of the kinematics of the remnant. These capabilities will open new avenues towards understanding the

  2. Micro- and Nanotechnologies for Intelligent and Responsive Biomaterial-Based Medical Systems

    PubMed Central

    Caldorera-Moore, Mary; Peppas, Nicholas A.

    2009-01-01

    Advances in medical treatments of a wide variety of pathophysiological conditions require the development of better therapeutic agents, as well as a combination of the required therapeutic agents with device-integrated biomaterials that can serve as sensors and carriers. Combination of micro- and nanofabricated systems with intelligent biomaterials that have the ability to sense and respond is a promising avenue for the development of better diagnostic and therapeutic medical systems. Micro- and nano-electromechanical systems (MEMs and NEMs) are now becoming a family of potentially powerful new technologies for drug delivery, diagnostic tools, and tissue engineering. Improvements in micro- and nano-fabrication technology have enhanced the ability to create better performing therapeutic systems for numerous pathophysiological applications. More importantly, MEMS and NEMS-based tissue regeneration scaffolds, biosensors, and drug delivery devices provide new opportunities to mimic the natural intelligence and response of biological systems. PMID:19758574

  3. Structural vibration control of micro/macro-manipulator using feedforward and feedback approaches

    SciTech Connect

    Lew, J.Y.; Cannon, D.W.; Magee, D.P.; Book, W.J.

    1995-09-01

    Pacific Northwest Laboratory (PDL) researchers investigated the combined use of two control approaches to minimize micro/macro-manipulator structural vibration: (1) modified input shaping and (2) inertial force active damping control. Modified input shaping (MIS) is used as a feedforward controller to modify reference input by canceling the vibratory motion. Inertial force active damping (IFAD) is applied as a feedback controller to increase the system damping and robustness to unexpected disturbances. Researchers implemented both control schemes in the PNL micro/macro flexible-link manipulator testbed collaborating with Georgia Institute of Technology. The experiments successfully demonstrated the effectiveness of two control approaches in reducing structural vibration. Based on the results of the experiments, the combined use of two controllers is recommended for a micro/macro manipulator to achieve the fastest response to commands while canceling disturbances from unexpected forces.

  4. Solid tumors of childhood display specific serum microRNA profiles

    PubMed Central

    Murray, Matthew J.; Raby, Katie L.; Saini, Harpreet K.; Bailey, Shivani; Wool, Sophie V.; Tunnacliffe, Jane M.; Enright, Anton J.; Nicholson, James C.; Coleman, Nicholas

    2014-01-01

    Background Serum biomarkers for diagnosis and risk-stratification of childhood solid tumors would improve the accuracy/timeliness of diagnosis and reduce the need for invasive biopsies. We hypothesized that differential expression and/or release of microRNAs by such tumors may be detected as altered serum microRNA profiles. Methods We undertook global quantitative-RT-PCR microRNA profiling (n=741) on RNA from 53 serum samples, representing 33 diagnostic cases of common childhood cancers plus 20 controls. Technical confirmation was performed in a subset of 21 cases, plus four independent samples. Results We incorporated robust quality-control steps for RNA extraction, qRT-PCR efficiency and hemolysis quantification. We evaluated multiple methods to normalize global profiling data and identified the ‘global-mean’ approach as optimal. We generated a panel of six microRNAs that were most stable in pediatric serum samples and therefore most suitable for normalization of targeted microRNA qRT-PCR data. Tumor-specific serum microRNA profiles were identified for each tumor type and selected microRNAs underwent confirmatory testing. We identified a panel of microRNAs (miR-124-3p/miR-9-3p/miR-218-5p/miR-490-5p/miR-1538) of potential importance in the clinical management of neuroblastoma, as they were consistently highly over-expressed in MYCN-amplified high-risk cases (MYCN-NB). We also derived candidate microRNA panels for non-invasive differential diagnosis of a liver mass (hepatoblastoma vs. combined MYCN-NB/NB), an abdominal mass (Wilms tumor vs. combined MYCN-NB/NB), and sarcoma subtypes. Conclusions This study describes a pipeline for robust diagnostic serum microRNA profiling in childhood solid tumors, and has identified candidate microRNA profiles for prospective testing. Impact We propose a new non-invasive method with the potential to diagnose childhood solid tumors. PMID:25416717

  5. Residual orientation in micro-injection molded parts

    SciTech Connect

    Healy, John; Edward, Graham H.; Knott, Robert B.

    2008-06-30

    The residual orientation following micro-injection molding of small rectangular plates with linear polyethylene has been examined using small-angle neutron scattering, and small- and wide-angle X-ray scattering. The effect of changing the molding conditions has been examined, and the residual chain orientation has been compared to the residual orientation of the crystallites as a function of position in the sample. This study has found that, for micromoldings, the orientation of the crystallites decreases with increasing injection speed and increasing mold thickness. The combined data suggest that the majority of the orientation present comes from oriented crystal growth rather than residual chain orientation.

  6. Optical Tweezers for Sample Fixing in Micro-Diffraction Experiments

    SciTech Connect

    Amenitsch, H.; Rappolt, M.; Sartori, B.; Laggner, P.; Cojoc, D.; Ferrari, E.; Garbin, V.; Di Fabrizio, E.; Burghammer, M.; Riekel, Ch.

    2007-01-19

    In order to manipulate, characterize and measure the micro-diffraction of individual structural elements down to single phospholipid liposomes we have been using optical tweezers (OT) combined with an imaging microscope. We were able to install the OT system at the microfocus beamline ID13 at the ESRF and trap clusters of about 50 multi-lamellar liposomes (< 10 {mu}m large cluster). Further we have performed a scanning diffraction experiment with a 1 micrometer beam to demonstrate the fixing capabilities and to confirm the size of the liposome cluster by X-ray diffraction.

  7. Nano-in-Micro Self-Reporting Hydrogel Constructs.

    PubMed

    Tirella, Annalisa; La Marca, Margherita; Brace, Leigh-Anne; Mattei, Giorgio; Aylott, Jonathan W; Ahluwalia, Arti

    2015-08-01

    Highly reproducible Nano-in-Micro constructs are fabricated to provide a well-defined and self-reporting biomimetic environment for hepatocytes. Based on a protein/hydrogel formulation with controlled shape, size and composition, the constructs enable efficient nutrient exchange and provide an adhesive 3D framework to cells. Co-encapsulation of hepatocytes and ratiometric optical nanosensors with pH sensitivity in the physiological range allows continuous monitoring of the microenvironment. The lobule-sized microbeads are fabricated using an automated droplet generator, Sphyga (Spherical Hydrogel Generator) combining alginate, collagen, decellularized hepatic tissue, pH-nanosensors and hepatocytes. The pH inside the Nano-in-Micro constructs is monitored during culture, while assaying media for hepatic function and vitality markers. Although the local pH changes by several units during bead fabrication, when encapsulated cells are most likely to undergo stress, it is stable and buffered by cell culture media thereafter. Albumin secretion and urea production are significantly higher in the microbeads compared with controls, indicating that the encapsulated Nano-in-Micro environment is conducive to enhanced hepatic function.

  8. The Promise of Macromolecular Crystallization in Micro-fluidic Chips

    NASA Technical Reports Server (NTRS)

    vanderWoerd, Mark; Ferree, Darren; Pusey, Marc

    2003-01-01

    Micro-fluidics, or lab on a chip technology, is proving to be a powerful, rapid, and efficient approach to a wide variety of bio-analytical and microscale bio-preparative needs. The low materials consumption, combined with the potential for packing a large number of experiments in a few cubic centimeters, makes it an attractive technique for both initial screening and subsequent optimization of macromolecular crystallization conditions. Screening operations, which require equilibrating macromolecule solution with a standard set of premixed solutions, are relatively straightforward and have been successfully demonstrated in a micro-fluidics platform. More complex optimization methods, where crystallization solutions are independently formulated from a range of stock solutions, are considerably more complex and have yet to be demonstrated. To be competitive with either approach, a micro-fluidics system must offer ease of operation, be able to maintain a sealed environment over several weeks to months, and give ready access for the observation of crystals as they are grown.

  9. Hot gas stream application in micro-bonding technique

    NASA Astrophysics Data System (ADS)

    Andrijasevic, Daniela; Giouroudi, Ioanna; Smetana, Walter; Boehm, Stefan; Brenner, Werner

    2006-01-01

    This paper presents a new concept for bonding micro-parts with dimensions in the range of 50 μm to 300 μm. Two different kinds of adhesives - polyurethane adhesive foil and hot melt glue - were applied to a basic substrate by different techniques. The focused and concentrated hot gas stream softened glue which had been applied in a solid state. Micro-parts were then embossed in the softened glue, or covered and shielded by it. In this way, a rigid and compact bond was obtained after cooling. For the positioning of micro-parts (optical fibers), it has been necessary to manufacture adequate V-grooves. Finite element analyses using the ANSYS TM program package were performed in order to evaluate parameters which govern the heat transfer to the adhesive and substrate respectively. Experimental results are in good agreement with results obtained by the numerical simulations. The advantages of this new approach are small system size, low capital costs, simple usage, applicability to many material combinations, easy integration into existing production lines, etc.

  10. MicroRNAs in Breast Cancer -Our Initial Results.

    PubMed

    Popovska-Jankovic, K; Noveski, P; Chakalova, L; Petrusevska, G; Kubelka, K; Plaseska-Karanfilska, D

    2012-12-01

    MicroRNAs (miRNAs) are small [∼21 nucleotide (nt)] non coding RNAs (ncRNAs) that regulate gene expression posttranscriptionally. About 3.0% of human genes encode for miRNAs, and up to 30.0% of human protein coding genes may be regulated by miRNAs. Currently, more than 2000 unique human mature microRNAs are known. MicroRNAs play a key role in diverse biological processes including development, cell proliferation, differentiation and apoptosis. These processes are commonly dysregulated in cancer, implicating miRNAs in carcinogenesis, where they act as tumor supressors or oncogenes. Several miRNAs are associated with breast cancer. Here we present our initial results of miRNA analyses of breast cancer tissues using quantitative real time-polymerase chain reaction (ReTi-PCR) (qPCR) involving stem-loop reverse transcriptase (RT) primers combined with TaqMan® PCR and miRNA microarray analysis.

  11. Micro-optical imaging concepts for an intraocular vision aid

    NASA Astrophysics Data System (ADS)

    Eix, Ilos; Stork, Wilhelm; Muller-Glaser, Klaus D.

    2004-03-01

    About 10 million people around the world are suffering from blindness, where the path of light is disturbed due to an opaque, irreversible damaged, and inoperable cornea. Although vision is not given to this group of population, the retina is still intact. To date, there is no artificial implant which is able to replace the natural cornea. The work presented here describes an approach to build and implant a micro-optical and microelectronic system to be used as an intraocular vision aid. By overcoming the disturbed light path, it yields to an improved visual acuity of the patient. The main aspect of this bio-mimetic system is to transfer information representing the patient's field of view to the retina. An image of the field of view is captured in real-time outside the eye. After employing data processing, it is wireless transferred to the implanted part of the vision aid. From there, the information emerging from a micro display is imaged to the retina via a micro-optical system. The limited display resolution available inside the eye and the limited dimensions of the eyeball build the constrains of the optical system. A combination of a spatial light modulator together with an imaging lens system realizes intelligent spatial information distribution schemes onto the retina. This ensures a high outcome of visual acuity in the central region of the retina. Various retinal acuities can be realized. The employment of in-vivo adjustment mechanisms of the focal plane is discussed.

  12. Wafer-scale micro-optics fabrication

    NASA Astrophysics Data System (ADS)

    Voelkel, Reinhard

    2012-07-01

    Micro-optics is an indispensable key enabling technology for many products and applications today. Probably the most prestigious examples are the diffractive light shaping elements used in high-end DUV lithography steppers. Highly-efficient refractive and diffractive micro-optical elements are used for precise beam and pupil shaping. Micro-optics had a major impact on the reduction of aberrations and diffraction effects in projection lithography, allowing a resolution enhancement from 250 nm to 45 nm within the past decade. Micro-optics also plays a decisive role in medical devices (endoscopes, ophthalmology), in all laser-based devices and fiber communication networks, bringing high-speed internet to our homes. Even our modern smart phones contain a variety of micro-optical elements. For example, LED flash light shaping elements, the secondary camera, ambient light and proximity sensors. Wherever light is involved, micro-optics offers the chance to further miniaturize a device, to improve its performance, or to reduce manufacturing and packaging costs. Wafer-scale micro-optics fabrication is based on technology established by the semiconductor industry. Thousands of components are fabricated in parallel on a wafer. This review paper recapitulates major steps and inventions in wafer-scale micro-optics technology. The state-of-the-art of fabrication, testing and packaging technology is summarized.

  13. Micro sun sensor for spacecraft attitude control

    NASA Technical Reports Server (NTRS)

    Mobasser, Sohrab; Liebe, Carl Christian

    2004-01-01

    A micro sun sensor is being developed for use on a Mars rover for the Mars Science Laboratory Mission. The micro sun sensor, which is basically a small pinhole camera, consists of a small mask with pinholes, placed on top of an image detector.

  14. A thermally self-sustained micro-power plant with integrated micro-solid oxide fuel cells, micro-reformer and functional micro-fluidic carrier

    NASA Astrophysics Data System (ADS)

    Scherrer, Barbara; Evans, Anna; Santis-Alvarez, Alejandro J.; Jiang, Bo; Martynczuk, Julia; Galinski, Henning; Nabavi, Majid; Prestat, Michel; Tölke, René; Bieberle-Hütter, Anja; Poulikakos, Dimos; Muralt, Paul; Niedermann, Philippe; Dommann, Alex; Maeder, Thomas; Heeb, Peter; Straessle, Valentin; Muller, Claude; Gauckler, Ludwig J.

    2014-07-01

    Low temperature micro-solid oxide fuel cell (micro-SOFC) systems are an attractive alternative power source for small-size portable electronic devices due to their high energy efficiency and density. Here, we report on a thermally self-sustainable reformer-micro-SOFC assembly. The device consists of a micro-reformer bonded to a silicon chip containing 30 micro-SOFC membranes and a functional glass carrier with gas channels and screen-printed heaters for start-up. Thermal independence of the device from the externally powered heater is achieved by exothermic reforming reactions above 470 °C. The reforming reaction and the fuel gas flow rate of the n-butane/air gas mixture controls the operation temperature and gas composition on the micro-SOFC membrane. In the temperature range between 505 °C and 570 °C, the gas composition after the micro-reformer consists of 12 vol.% to 28 vol.% H2. An open-circuit voltage of 1.0 V and maximum power density of 47 mW cm-2 at 565 °C is achieved with the on-chip produced hydrogen at the micro-SOFC membranes.

  15. Micro Electro Discharge Machining of Electrically Nonconductive Ceramics

    SciTech Connect

    Schubert, A.; Zeidler, H.; Hackert, M.; Wolf, N.

    2011-05-04

    EDM is a known process for machining of hard and brittle materials. Due to its noncontact and nearly forceless behaviour, it has been introduced into micro manufacturing and through constant development it is now an important means for producing high-precision micro geometries. One restriction of EDM is its limitation to electrically conducting materials.Today many applications, especially in the biomedical field, make use of the benefits of ceramic materials, such as high strength, very low wear and biocompatibility. Common ceramic materials such as Zirconium dioxide are, due to their hardness in the sintered state, difficult to machine with conventional cutting techniques. A demand for the introduction of EDM to these materials could so far not be satisfied because of their nonconductive nature.At the Chemnitz University of Technology and the Fraunhofer IWU, investigations in the applicability of micro-EDM for the machining of nonconductive ceramics are being conducted. Tests are undertaken using micro-EDM drilling with Tungsten carbide tool electrodes and ZrO{sub 2} ceramic workpieces. A starting layer, in literature often referred to as 'assisting electrode' is used to set up a closed electric circuit to start the EDM process. Combining carbon hydride based dielectric and a specially designed low-frequency vibration setup to excite the workpiece, the process environment can be held within parameters to allow for a constant EDM process even after the starting layer is machined. In the experiments a cylindrical 120 {mu}m diameter Tungsten carbide tool electrode and Y{sub 2}O{sub 3}- and MgO- stabilized ZrO{sub 2} worpieces are used. The current and voltage signals of the discharges within the different stages of the process (machining of the starting layer, machining of the base material, transition stage) are recorded and their characteristics compared to discharges in metallic material. Additionally, the electrode feed is monitored. The influences of the

  16. Acoustic emissions in rock deformation experiments under micro-CT

    NASA Astrophysics Data System (ADS)

    Tisato, Nicola; Goodfellow, Sebastian D.; Moulas, Evangelos; Di Toro, Giulio; Young, Paul; Grasselli, Giovanni

    2016-04-01

    The study of acoustic emissions (AE) generated by rocks undergoing deformation has become, in the last decades, one of the most powerful tools for boosting our understanding of the mechanisms which are responsible for rock failures. AE are elastic waves emitted by the local failure of micro- or milli-metric portions of the tested specimen. At the same time, X-ray micro computed tomography (micro-CT) has become an affordable, reliable and powerful tool for imaging the internal structure of rock samples. In particular, micro-CT coupled with a deformation apparatus offers the unique opportunity for observing, without perturbing, the sample while the deformation and the formation of internal structures, such as shear bands, is ongoing. Here we present some preliminary results gathered with an innovative apparatus formed by the X-ray transparent pressure vessel called ERDμ equipped with AE sensors, an AE acquisition system and a micro-CT apparatus available at the University of Toronto. The experiment was performed on a 12 mm diameter 36 mm long porous glass sample which was cut on a 60 deg inclined plane (i.e. saw-cut sample). Etna basaltic sand with size ~1 mm was placed between the two inclined faces forming an inclined fault zone with ~2 mm thickness. The sample assembly was jacketed with a polyefin shrink tube and two AE sensors were glued onto the glass samples above and below the fault zone. The sample was then enclosed in the pressure vessel and confined with compressed air up to 3 MPa. A third AE sensor was placed outside the vessel. The sample was saturated with water and AE were generated by varying the fluid and confining pressure or the vertical force, causing deformations concentrated in the fault zone. Mechanical data and AE traces were collected throughout the entire experiment which lasted ~24 hours. At the same time multiple micro-CT 3D datasets and 2D movie-radiographies were collected, allowing the 3D reconstruction of the deformed sample at

  17. Micro-Inspector Spacecraft for Space Exploration Missions

    NASA Technical Reports Server (NTRS)

    Mueller, Juergen; Alkalai, Leon; Lewis, Carol

    2005-01-01

    NASA is seeking to embark on a new set of human and robotic exploration missions back to the Moon, to Mars, and destinations beyond. Key strategic technical challenges will need to be addressed to realize this new vision for space exploration, including improvements in safety and reliability to improve robustness of space operations. Under sponsorship by NASA's Exploration Systems Mission, the Jet Propulsion Laboratory (JPL), together with its partners in government (NASA Johnson Space Center) and industry (Boeing, Vacco Industries, Ashwin-Ushas Inc.) is developing an ultra-low mass (<3.0 kg) free-flying micro-inspector spacecraft in an effort to enhance safety and reduce risk in future human and exploration missions. The micro-inspector will provide remote vehicle inspections to ensure safety and reliability, or to provide monitoring of in-space assembly. The micro-inspector spacecraft represents an inherently modular system addition that can improve safety and support multiple host vehicles in multiple applications. On human missions, it may help extend the reach of human explorers, decreasing human EVA time to reduce mission cost and risk. The micro-inspector development is the continuation of an effort begun under NASA's Office of Aerospace Technology Enabling Concepts and Technology (ECT) program. The micro-inspector uses miniaturized celestial sensors; relies on a combination of solar power and batteries (allowing for unlimited operation in the sun and up to 4 hours in the shade); utilizes a low-pressure, low-leakage liquid butane propellant system for added safety; and includes multi-functional structure for high system-level integration and miniaturization. Versions of this system to be designed and developed under the H&RT program will include additional capabilities for on-board, vision-based navigation, spacecraft inspection, and collision avoidance, and will be demonstrated in a ground-based, space-related environment. These features make the micro

  18. Micro/nanoscale continuous printing: direct-writing of wavy micro/nano structures via electrospinning

    NASA Astrophysics Data System (ADS)

    Fang, Feiyu; Du, Zefeng; Zeng, Jun; Zhu, Ziming; Chen, Xin; Chen, Xindu; Lv, Yuanjun; Wang, Han

    2015-07-01

    Micro/nanofibers that are created by direct-writing using an electrospinning (ES) technique have aroused much recent attention, owing to their intriguing physical properties and great potential as building blocks for micro/nanoscale devices. In this work, a wavy direct-writing (WDW) process was developed to directly write wavy micro/nanostructures suitable for the fabrication of micro/nanoscale devices. The low voltage WDW technique is anticipated to be useful for a broad range of applications including flexible/stretchable electronics, micro optoelectronics, nano-antennas, microelectromechanical systems (MEMS), and biomedical engineering.

  19. Understanding the micro structure of Berea Sandstone by the simultaneous use of micro-computed tomography (micro-CT) and focused ion beam-scanning electron microscopy (FIB-SEM).

    PubMed

    Bera, Bijoyendra; Mitra, Sushanta K; Vick, Douglas

    2011-07-01

    Berea sandstone is the building block for reservoirs containing precious hydrocarbon fuel. In this study, we comprehensively reveal the microstructure of Berea sandstone, which is often treated as a porous material with interconnected micro-pores of 2-5 μm. This has been possible due to the combined application of micro-computed tomography (CT) and focused ion beam (FIB)-scanning electron microscopy (SEM) on a Berea sample. While the use of micro-CT images are common for geological materials, the clubbing and comparison of tomography on Berea with state-of-the-art microstructure imaging techniques like FIB-SEM reveals some unforeseen features of Berea microstructure. In particular, for the first time FIB-SEM has been used to understand the micro-structure of reservoir rock material like Berea sandstone. By using these characterization tools, we are able to show that the micro-pores (less than 30 μm) are absent below the solid material matrix, and that it has small interconnected pores (30-40 μm) and large crater-like voids (100-250 μm) throughout the bulk material. Three-dimensional pore space reconstructions have been prepared from the CT images. Accordingly, characterization of Berea sandstone specimen is performed by calculation of pore-structure volumes and determination of porosity values.

  20. MicroRNAs in plants

    PubMed Central

    Purugganan, Michael

    2008-01-01

    MicroRNAs (miRNAs) are important posttranscriptional regulators of gene expression in eukaryotes. In plants, most miRNAs exist in multiple copies throughout the genome and many of these miRNAs target multiple messenger RNA (mRNA) transcripts. Mutations at miRNAs in natural populations could facilitate evolutionary changes within and between species because of their positions at critical positions in gene regulatory networks. Dissecting the contribution of miRNAs to plant evolution requires the identification of potentially functional mutations at miRNAs within and between species. Recently, we and others have published papers focused on this topic, laying the foundation for studying the contributions of miRNAs to the phenotypic diversification of plants. PMID:19704512

  1. MicroRNAs and atherosclerosis

    PubMed Central

    Madrigal-Matute, Julio; Rotllan, Noemi; Aranda, Juan F.; Fernández-Hernando, Carlos

    2014-01-01

    MicroRNAs (miRNAs) are small (~22nucleotide) sequences of RNA that regulate gene expression at posttranscriptional level. MiRNA/mRNA base pairing complementarity provokes mRNA decay and consequent gene silencing. These endogenous gene expression inhibitors were primarily described in cancer but recent exciting findings have also demonstrated a key role in cardiovascular diseases (CVDs) including atherosclerosis. MiRNAs controls endothelial cell (EC), vascular smooth muscle cell (VSMC) and macrophage functions, and thereby regulate the progression of atherosclerosis. MiRNAs expression is modulated by different stimuli involved in every stage of atherosclerosis and conversely miRNAs modulates several pathways implicated in plaque development such as cholesterol metabolism. In the present review, we focus on the importance of miRNAs in atherosclerosis and we further discuss their potential use as biomarkers and therapeutic targets in CVDs. PMID:23512606

  2. Micro-tensile testing system

    DOEpatents

    Wenski, Edward G.

    2007-07-17

    A micro-tensile testing system providing a stand-alone test platform for testing and reporting physical or engineering properties of test samples of materials having thicknesses of approximately between 0.002 inch and 0.030 inch, including, for example, LiGA engineered materials. The testing system is able to perform a variety of static, dynamic, and cyclic tests. The testing system includes a rigid frame and adjustable gripping supports to minimize measurement errors due to deflection or bending under load; serrated grips for securing the extremely small test sample; high-speed laser scan micrometers for obtaining accurate results; and test software for controlling the testing procedure and reporting results.

  3. Micro-tensile testing system

    DOEpatents

    Wenski, Edward G.

    2007-08-21

    A micro-tensile testing system providing a stand-alone test platform for testing and reporting physical or engineering properties of test samples of materials having thicknesses of approximately between 0.002 inch and 0.030 inch, including, for example, LiGA engineered materials. The testing system is able to perform a variety of static, dynamic, and cyclic tests. The testing system includes a rigid frame and adjustable gripping supports to minimize measurement errors due to deflection or bending under load; serrated grips for securing the extremely small test sample; high-speed laser scan micrometers for obtaining accurate results; and test software for controlling the testing procedure and reporting results.

  4. Micro-tensile testing system

    DOEpatents

    Wenski, Edward G.

    2006-01-10

    A micro-tensile testing system providing a stand-alone test platform for testing and reporting physical or engineering properties of test samples of materials having thicknesses of approximately between 0.002 inch and 0.030 inch, including, for example, LiGA engineered materials. The testing system is able to perform a variety of static, dynamic, and cyclic tests. The testing system includes a rigid frame and adjustable gripping supports to minimize measurement errors due to deflection or bending under load; serrated grips for securing the extremely small test sample; high-speed laser scan micrometers for obtaining accurate results; and test software for controlling the testing procedure and reporting results.

  5. MicroRNAs in neurodegeneration.

    PubMed

    Bushati, Natascha; Cohen, Stephen M

    2008-06-01

    microRNAs (miRNAs) act as post-transcriptional regulators of gene expression in diverse cellular and developmental processes. Many miRNAs are expressed specifically in the central nervous system, where they have roles in differentiation, neuronal survival, and potentially also in plasticity and learning. The absence of miRNAs in a variety of specific postmitotic neurons can lead to progressive loss of these neurons and behavioral defects reminiscent of the phenotypes seen in the pathologies of neurodegenerative diseases. Here, we review recent studies which provide a link between miRNA function and neurodegeneration. We also discuss evidence which might suggest involvement of miRNAs in the emergence or progression of neurodegenerative diseases.

  6. An electromagnetic micro=undulator

    SciTech Connect

    Nassiri, A.; Turner, L.R.

    1997-12-31

    Microfabrication technology using the LIGA (a German acronym for Lithography, Electroforming, and Molding) process offers an attractive alternative for fabricating precision devices with micron-sized features. One such device is a mm-sized micro-undulator with potential applications in a table-top synchrotron light source for medical and other industrial uses. The undulator consists of a silver conductor embedded in poles and substrate of nickel-iron. Electromagnetic modeling of the undulator is done using the eddy current computer code ELEKTRA. Computations predict a field pattern of appropriate strength and quality if the current can be prevented from being shunted from silver by the nickel-iron poles either through insulation or through slotted poles. The design of the undulator along with the computational results are discussed.

  7. Dysregulated microRNAs in neurodegenerative disorders.

    PubMed

    Lau, Pierre; de Strooper, Bart

    2010-09-01

    The complexity of the nervous system arises in part, from the large diversity of neural cell types that support the architecture of neuronal circuits. Recent studies have highlighted microRNAs as important players in regulating gene expression at the post-transcriptional level and therefore the phenotype of neural cells. A link between microRNAs and neurodegenerative diseases such as Alzheimer's disease, Huntington's disease and Parkinson's disease is becoming increasingly evident. Here, we discuss microRNAs in neurodegeneration, from the fruit fly and mouse utilized as experimental models to dysregulated microRNAs in human neurodegenerative disorders. We propose that studying microRNAs and their mRNA targets in the context of neurodegeneration will significantly contribute to the identification of proteins important for neuronal function and might reveal underlying molecular networks that drive these diseases.

  8. Micro-CT imaging of Randall's plaques.

    PubMed

    Williams, James C; Lingeman, James E; Coe, Fredric L; Worcester, Elaine M; Evan, Andrew P

    2015-01-01

    Micro-computed tomographic imaging (micro-CT) provides unprecedented information on stone structure and mineral composition. High-resolution micro-CT even allows visualization of the lumens of tubule and/or vessels within Randall's plaque, on stones or in papillary biopsies, thus giving a non-destructive way to study these sites of stone adhesion. This paper also shows an example of a stone growing on a different anchoring mechanism: a mineral plug within the lumen of a Bellini duct (BD plug). Micro-CT shows striking structural differences between stones that have grown on Randall's plaque and those that have grown on BD plugs. Thus, Randall's plaque can be distinguished by micro-CT, and this non-destructive method shows great promise in helping to elucidate the different mechanisms by which small stones are retained in the kidney during the development of nephrolithiasis. PMID:25096802

  9. Micro-Scale Regenerative Heat Exchanger

    NASA Technical Reports Server (NTRS)

    Moran, Matthew E.; Stelter, Stephan; Stelter, Manfred

    2004-01-01

    A micro-scale regenerative heat exchanger has been designed, optimized and fabricated for use in a micro-Stirling device. Novel design and fabrication techniques enabled the minimization of axial heat conduction losses and pressure drop, while maximizing thermal regenerative performance. The fabricated prototype is comprised of ten separate assembled layers of alternating metal-dielectric composite. Each layer is offset to minimize conduction losses and maximize heat transfer by boundary layer disruption. A grating pattern of 100 micron square non-contiguous flow passages were formed with a nominal 20 micron wall thickness, and an overall assembled ten-layer thickness of 900 microns. Application of the micro heat exchanger is envisioned in the areas of micro-refrigerators/coolers, micropower devices, and micro-fluidic devices.

  10. Biologically Inspired Micro-Flight Research

    NASA Technical Reports Server (NTRS)

    Raney, David L.; Waszak, Martin R.

    2003-01-01

    Natural fliers demonstrate a diverse array of flight capabilities, many of which are poorly understood. NASA has established a research project to explore and exploit flight technologies inspired by biological systems. One part of this project focuses on dynamic modeling and control of micro aerial vehicles that incorporate flexible wing structures inspired by natural fliers such as insects, hummingbirds and bats. With a vast number of potential civil and military applications, micro aerial vehicles represent an emerging sector of the aerospace market. This paper describes an ongoing research activity in which mechanization and control concepts for biologically inspired micro aerial vehicles are being explored. Research activities focusing on a flexible fixed- wing micro aerial vehicle design and a flapping-based micro aerial vehicle concept are presented.

  11. microRNA-encoded behaviour in Drosophila+

    PubMed Central

    Picao-Osorio, Joao; Johnston, Jamie; Landgraf, Matthias; Berni, Jimena; Alonso, Claudio R.

    2016-01-01

    The relationship between microRNA regulation and the specification of behaviour is only beginning to be explored. Here we find that mutation of a single microRNA locus (miR-iab4/8) in Drosophila larvae affects the animal’s capacity to correct its orientation if turned upside-down (self-righting). One of the microRNA targets involved in this behaviour is the Hox gene Ultrabithorax whose derepression in two metameric neurons leads to self-righting defects. In vivo neural activity analysis reveals that these neurons, the self-righting node (SRN), have different activity patterns in wild type and miRNA mutants whilst thermogenetic manipulation of SRN activity results in changes in self-righting behaviour. Our work thus reveals a microRNA-encoded behaviour and suggests that other microRNAs might also be involved in behavioural control in Drosophila and other species. PMID:26494171

  12. Improving metrology for micro-optics manufacturing

    NASA Astrophysics Data System (ADS)

    Davies, Angela D.; Bergner, Brent C.; Gardner, Neil W.

    2003-11-01

    Metrology is one of the critical enabling technologies for realizing the full market potential for micro-optical systems. Measurement capabilities are currently far behind present and future needs. Much of today"s test equipment was developed for the micro-electronics industry and is not optimized for micro-optic materials and geometries. Metrology capabilities currently limit the components that can be realized, in many cases. Improved testing will be come increasingly important as the technology moves to integration where it will become important to "test early and test often" to achieve high yields. In this paper, we focus on micro-refractive components in particular, and describe measurement challenges for this class of components and current and future needs. We also describe a new micro-optics metrology research program at UNC Charlotte under the Center for Precision Metrology and the new Center for Optoelectronics and Optical Communications to address these needs.

  13. Micro and Nano Systems for Space Exploration

    NASA Technical Reports Server (NTRS)

    Manohara, Harish

    2007-01-01

    This slide presentation reviews the use of micro and nano systems in Space exploration. Included are: an explanation of the rationales behind nano and micro technologies for space exploration, a review of how the devices are fabricated, including details on lithography with more information on Electron Beam (E-Beam) lithography, and X-ray lithography, a review of micro gyroscopes and inchworm Microactuator as examples of the use of MicroElectoMechanical (MEMS) technology. Also included is information on Carbon Nanotubes, including a review of the CVD growth process. These micro-nano systems have given rise to the next generation of miniature X-ray Diffraction, X-ray Fluorescence instruments, mass spectrometers, and terahertz frequency vacuum tube oscillators and amplifiers, scanning electron microscopes and energy dispersive x-ray spectroscope. The nanotechnology has also given rise to coating technology, such as silicon nanotip anti-reflection coating.

  14. MicroRNA involvement in glioblastoma pathogenesis

    SciTech Connect

    Novakova, Jana; Slaby, Ondrej; Vyzula, Rostislav; Michalek, Jaroslav

    2009-08-14

    MicroRNAs are endogenously expressed regulatory noncoding RNAs. Altered expression levels of several microRNAs have been observed in glioblastomas. Functions and direct mRNA targets for these microRNAs have been relatively well studied over the last years. According to these data, it is now evident, that impairment of microRNA regulatory network is one of the key mechanisms in glioblastoma pathogenesis. MicroRNA deregulation is involved in processes such as cell proliferation, apoptosis, cell cycle regulation, invasion, glioma stem cell behavior, and angiogenesis. In this review, we summarize the current knowledge of miRNA functions in glioblastoma with an emphasis on its significance in glioblastoma oncogenic signaling and its potential to serve as a disease biomarker and a novel therapeutic target in oncology.

  15. Micro-bubble Enhanced Sonoporation

    NASA Astrophysics Data System (ADS)

    Tachibana, Rie; Okamoto, Akio; Yoshinaka, Kiyoshi; Takagi, Shu; Matsumoto, Yoichiro

    2010-03-01

    A gene transfer system that uses ultrasound, known as sonoporation, has recently been developed, and it is known that micro-bubbles can help gene transfection in this technique. However, the mechanism and optimal induction conditions have not yet been fully clarified. We examined the factors that affect the gene induction rate, and attempted to devise a method for high-efficiency gene induction. In vitro, we inducted a GFP-containing plasmid into fibroblast cells (NIH3T3) using an ultrasound contrast agent (Sonazoid®, or micro-bubbles) and piezoelectric transducer. Cells were cultured on 24-well plates. The GFP-containing plasmid (concentration: 15 mg/ml) and Sonazoid® were mixed with the cell suspension. Ultrasound frequency was 2.0 MHz (burst wave, duty cycle: 10%), ultrasound intensity was varied from 0 W/cm2 to 11.0 W/cm2, exposure time ranged from 0 s to 120 s, and burst repetition frequency was varied from 50 Hz to 50000 Hz. Gene induction ratio was higher with stronger or longer ultrasound exposure, and gene induction ratio was affected by ultrasound burst repetition frequency. However, the ratio was less than 1%. We also measured cell survival and visualized cells with holes using propidium iodide. We found that about 80% of cells were alive, and many cells developed holes with ultrasound exposure at a burst repetition frequency of 5 kHz. These results suggest that fewer genes enter the cells or are expressed under these conditions. These problems require further study.

  16. MicroRNA-339 and microRNA-556 regulate Klotho expression in vitro.

    PubMed

    Mehi, Stephen J; Maltare, Astha; Abraham, Carmela R; King, Gwendalyn D

    2014-02-01

    Klotho is an anti-aging protein with direct effects on life-span in mice. Klotho functions to regulate pathways classically associated with longevity including insulin/IGF1 and Wnt signaling. Decreased Klotho protein expression is observed throughout the body during the normal aging process. While increased methylation of the Klotho promoter is reported, other epigenetic mechanisms could contribute to age-related downregulation of Klotho expression, including microRNA-mediated regulation. Following in silico identification of potential microRNA binding sites within the Klotho 3' untranslated region, reporter assays reveal regulation by microRNA-339, microRNA-556, and, to a lesser extent, microRNA-10 and microRNA-199. MicroRNA-339 and microRNA-556 were further found to directly decrease Klotho protein expression indicating that, if upregulated in aging tissue, these microRNA could play a role in age-related downregulation of Klotho messenger RNA. These microRNAs are differentially regulated in cancer cells compared to normal cells and may imply a role for microRNA-mediated regulation of Klotho in cancer. PMID:23818104

  17. Hierarchically micro-patterned nanofibrous scaffolds with a nanosized bio-glass surface for accelerating wound healing

    NASA Astrophysics Data System (ADS)

    Xu, He; Lv, Fang; Zhang, Yali; Yi, Zhengfang; Ke, Qinfei; Wu, Chengtie; Liu, Mingyao; Chang, Jiang

    2015-11-01

    A composite scaffold with a controlled micro-pattern, nano-sized fiber matrix and surface-modified nanobioglass component was successfully prepared for skin wound healing by combining the patterning electrospinning with pulsed laser deposition strategies, and the hierarchical micro/nano structures and nano-sized bioglass in the scaffolds could synergistically improve the efficiency and re-epithelialization of wound healing.A composite scaffold with a controlled micro-pattern, nano-sized fiber matrix and surface-modified nanobioglass component was successfully prepared for skin wound healing by combining the patterning electrospinning with pulsed laser deposition strategies, and the hierarchical micro/nano structures and nano-sized bioglass in the scaffolds could synergistically improve the efficiency and re-epithelialization of wound healing. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr04802h

  18. Morphological Characterisation of Unstained and Intact Tissue Micro-architecture by X-ray Computed Micro- and Nano-Tomography

    PubMed Central

    Walton, Lucy A.; Bradley, Robert S.; Withers, Philip J.; Newton, Victoria L.; Watson, Rachel E. B.; Austin, Clare; Sherratt, Michael J.

    2015-01-01

    Characterisation and quantification of tissue structures is limited by sectioning-induced artefacts and by the difficulties of visualising and segmenting 3D volumes. Here we demonstrate that, even in the absence of X-ray contrast agents, X-ray computed microtomography (microCT) and nanotomography (nanoCT) can circumvent these problems by rapidly resolving compositionally discrete 3D tissue regions (such as the collagen-rich adventitia and elastin-rich lamellae in intact rat arteries) which in turn can be segmented due to their different X-ray opacities and morphologies. We then establish, using X-ray tomograms of both unpressurised and pressurised arteries that intra-luminal pressure not only increases lumen cross-sectional area and straightens medial elastic lamellae but also induces profound remodelling of the adventitial layer. Finally we apply microCT to another human organ (skin) to visualise the cell-rich epidermis and extracellular matrix-rich dermis and to show that conventional histological and immunohistochemical staining protocols are compatible with prior X-ray exposure. As a consequence we suggest that microCT could be combined with optical microscopy to characterise the 3D structure and composition of archival paraffin embedded biological materials and of mechanically stressed dynamic tissues such as the heart, lungs and tendons. PMID:25975937

  19. Morphological Characterisation of Unstained and Intact Tissue Micro-architecture by X-ray Computed Micro- and Nano-Tomography.

    PubMed

    Walton, Lucy A; Bradley, Robert S; Withers, Philip J; Newton, Victoria L; Watson, Rachel E B; Austin, Clare; Sherratt, Michael J

    2015-05-15

    Characterisation and quantification of tissue structures is limited by sectioning-induced artefacts and by the difficulties of visualising and segmenting 3D volumes. Here we demonstrate that, even in the absence of X-ray contrast agents, X-ray computed microtomography (microCT) and nanotomography (nanoCT) can circumvent these problems by rapidly resolving compositionally discrete 3D tissue regions (such as the collagen-rich adventitia and elastin-rich lamellae in intact rat arteries) which in turn can be segmented due to their different X-ray opacities and morphologies. We then establish, using X-ray tomograms of both unpressurised and pressurised arteries that intra-luminal pressure not only increases lumen cross-sectional area and straightens medial elastic lamellae but also induces profound remodelling of the adventitial layer. Finally we apply microCT to another human organ (skin) to visualise the cell-rich epidermis and extracellular matrix-rich dermis and to show that conventional histological and immunohistochemical staining protocols are compatible with prior X-ray exposure. As a consequence we suggest that microCT could be combined with optical microscopy to characterise the 3D structure and composition of archival paraffin embedded biological materials and of mechanically stressed dynamic tissues such as the heart, lungs and tendons.

  20. Morphological Characterisation of Unstained and Intact Tissue Micro-architecture by X-ray Computed Micro- and Nano-Tomography.

    PubMed

    Walton, Lucy A; Bradley, Robert S; Withers, Philip J; Newton, Victoria L; Watson, Rachel E B; Austin, Clare; Sherratt, Michael J

    2015-01-01

    Characterisation and quantification of tissue structures is limited by sectioning-induced artefacts and by the difficulties of visualising and segmenting 3D volumes. Here we demonstrate that, even in the absence of X-ray contrast agents, X-ray computed microtomography (microCT) and nanotomography (nanoCT) can circumvent these problems by rapidly resolving compositionally discrete 3D tissue regions (such as the collagen-rich adventitia and elastin-rich lamellae in intact rat arteries) which in turn can be segmented due to their different X-ray opacities and morphologies. We then establish, using X-ray tomograms of both unpressurised and pressurised arteries that intra-luminal pressure not only increases lumen cross-sectional area and straightens medial elastic lamellae but also induces profound remodelling of the adventitial layer. Finally we apply microCT to another human organ (skin) to visualise the cell-rich epidermis and extracellular matrix-rich dermis and to show that conventional histological and immunohistochemical staining protocols are compatible with prior X-ray exposure. As a consequence we suggest that microCT could be combined with optical microscopy to characterise the 3D structure and composition of archival paraffin embedded biological materials and of mechanically stressed dynamic tissues such as the heart, lungs and tendons. PMID:25975937

  1. Morphological Characterisation of Unstained and Intact Tissue Micro-architecture by X-ray Computed Micro- and Nano-Tomography

    NASA Astrophysics Data System (ADS)

    Walton, Lucy A.; Bradley, Robert S.; Withers, Philip J.; Newton, Victoria L.; Watson, Rachel E. B.; Austin, Clare; Sherratt, Michael J.

    2015-05-01

    Characterisation and quantification of tissue structures is limited by sectioning-induced artefacts and by the difficulties of visualising and segmenting 3D volumes. Here we demonstrate that, even in the absence of X-ray contrast agents, X-ray computed microtomography (microCT) and nanotomography (nanoCT) can circumvent these problems by rapidly resolving compositionally discrete 3D tissue regions (such as the collagen-rich adventitia and elastin-rich lamellae in intact rat arteries) which in turn can be segmented due to their different X-ray opacities and morphologies. We then establish, using X-ray tomograms of both unpressurised and pressurised arteries that intra-luminal pressure not only increases lumen cross-sectional area and straightens medial elastic lamellae but also induces profound remodelling of the adventitial layer. Finally we apply microCT to another human organ (skin) to visualise the cell-rich epidermis and extracellular matrix-rich dermis and to show that conventional histological and immunohistochemical staining protocols are compatible with prior X-ray exposure. As a consequence we suggest that microCT could be combined with optical microscopy to characterise the 3D structure and composition of archival paraffin embedded biological materials and of mechanically stressed dynamic tissues such as the heart, lungs and tendons.

  2. Micro-Raman and micro-XRF analysis of glass beads from the Chungde site, Taiwan

    NASA Astrophysics Data System (ADS)

    Liou, Y. S.; Wang, S. C.; Liu, Y. C.

    2014-12-01

    A large number of ancient glass beads dating back from Late Neolithic Age to early Historical Period (ca. 2300-400 BP) of Taiwan have been uncovered from archaeological sites. These glass beads with variant colors, shapes, and stylistics have long been considered to possess socio-cultural significance. Due to the color and chemical composition of glass bead might be determined by raw materials, fluxing agents, colorants, opacifiers and stabilizers. In addition, ancient glass beads are rare and precious, non-destructive analysis has been employed to decipher about the provenances, manufacturing techniques, and exchange/trade routes. In this work, micro-Raman spectroscopy and micro X-ray fluorescent spectrometer (μ-XRF) were used to examine ten ancient glass beads excavated from the Chungde site, Hualien, Taiwan, dating back to 1500-800 BP, to unravel the mineralogical and chemical compositions. Micro Raman experimental results show that glass and anorthite glass are the main constituents accompanying with trace level of quartz, albite, siderite, ankerite, and amazonite. The Raman Index of Polymerization (Ip) indicate that the sintering temperature of the glass beads is in the range of 1000~1400°C. Furthermore, the chemical compositions are corresponding to the maximum stretching vibration peak wave number (νmax Si-O Stretching) and the maximum bending vibration peak wave number (δmax Si-O Bending), which are essentially consistent with that of the India-Pacific beads. The μ-XRF results indicate the presence of oxides including SiO2, Al2O3, Fe2O3, Na2O, K2O, CaO, MgO, SnO2, TiO2, CuO, etc., and could be classified to high aluminum of soda-lime glass system. According to ternary phase diagram analysis of CaO-K2O-Na2O and K2O-Al2O3-CaO, the ancient glass beads analyzed could be attributed to the India-Pacific beads, and is in accordance with that of Raman spectra. The combination of these facts leads to the conclusion that glass beads obtained from the Chungde

  3. Experimental study of micro electrical discharge machining discharges

    SciTech Connect

    Braganca, I. M. F.; Rosa, P. A. R.; Martins, P. A. F.; Dias, F. M.; Alves, L. L.

    2013-06-21

    Micro electrical discharge machining ({mu}EDM) is an atmospheric-pressure plasma-assisted technology that uses point-to-plane discharges in liquid dielectrics to remove microscopic quantities of electrically conductive materials. In this work, an innovative {mu}EDM prototype machine was specifically designed and fabricated to produce and control single spark discharges, thus, resolving the typical limitations of (multi-discharge) commercial machines. The work analyses the type of discharge and the micro-plasma electron-density values obtained for 0.5-38 {mu}m gap sizes, 3-10 000 {mu}s pulse durations, 75-250 V low breakdown voltages, and 1-20 A discharge currents, using different combinations of metallic electrodes in oil and in water. Results allow fitting, for micro-scale and low voltages, an empirical law between the maximum gap-size for breakdown, the breakdown voltage, and the effective stress-time. The electron density n{sub e} is obtained by optical emission spectroscopy diagnostics of the H{sub {alpha}}-line Stark broadening (yielding n{sub e}{approx}10{sup 16}-10{sup 17} cm{sup -3}, i.e., ionization degrees of {approx}2 Multiplication-Sign 10{sup -5}-10{sup -4}) and by a semi-empirical resistive plasma model. The model uses the experimental values of several electrical and geometrical quantities, and of the gas pressure estimated as {approx}60 bar-2 kbar from measurements of the plasma mechanical action, obtained using a force sensor. The quantitative information of this phenomenological study can assist the optimization of this micro-fabrication technique.

  4. Experimental study of micro electrical discharge machining discharges

    NASA Astrophysics Data System (ADS)

    Bragança, I. M. F.; Rosa, P. A. R.; Dias, F. M.; Martins, P. A. F.; Alves, L. L.

    2013-06-01

    Micro electrical discharge machining (μEDM) is an atmospheric-pressure plasma-assisted technology that uses point-to-plane discharges in liquid dielectrics to remove microscopic quantities of electrically conductive materials. In this work, an innovative μEDM prototype machine was specifically designed and fabricated to produce and control single spark discharges, thus, resolving the typical limitations of (multi-discharge) commercial machines. The work analyses the type of discharge and the micro-plasma electron-density values obtained for 0.5-38 μm gap sizes, 3-10 000 μs pulse durations, 75-250 V low breakdown voltages, and 1-20 A discharge currents, using different combinations of metallic electrodes in oil and in water. Results allow fitting, for micro-scale and low voltages, an empirical law between the maximum gap-size for breakdown, the breakdown voltage, and the effective stress-time. The electron density ne is obtained by optical emission spectroscopy diagnostics of the Hα-line Stark broadening (yielding ne˜1016-1017 cm-3, i.e., ionization degrees of ˜2×10-5-10-4) and by a semi-empirical resistive plasma model. The model uses the experimental values of several electrical and geometrical quantities, and of the gas pressure estimated as ˜60 bar-2 kbar from measurements of the plasma mechanical action, obtained using a force sensor. The quantitative information of this phenomenological study can assist the optimization of this micro-fabrication technique.

  5. Characterization of polydimethylsiloxane (PDMS) properties for biomedical micro/nanosystems.

    PubMed

    Mata, Alvaro; Fleischman, Aaron J; Roy, Shuvo

    2005-12-01

    Polydimethylsiloxane (PDMS Sylgard 184, Dow Corning Corporation) pre-polymer was combined with increasing amounts of cross-linker (5.7, 10.0, 14.3, 21.4, and 42.9 wt.%) and designated PDMS1, PDMS2, PDMS3, PDMS4, and PDMS5, respectively. These materials were processed by spin coating and subjected to common micro-fabrication, micro-machining, and biomedical processes: chemical immersion, oxygen plasma treatment, sterilization, and exposure to tissue culture media. The PDMS formulations were analyzed by gravimetry, goniometry, tensile testing, nano-indentation, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). Spin coating of PDMS was formulation dependent with film thickness ranging from 308 microm on PDMS1 to 171 microm on PDMS5 at 200 revolutions per minute (rpm). Ultimate tensile stress (UTS) increased from 3.9 MPa (PDMS1) to 10.8 MPa (PDMS3), and then decreased down to 4.0 MPa (PDMS5). Autoclave sterilization (AS) increased the storage modulus (sigma) and UTS in all formulations, with the highest increase in UTS exhibited by PDMS5 (218%). PDMS surface hydrophilicity and micro-textures were generally unaffected when exposed to the different chemicals, except for micro-texture changes after immersion in potassium hydroxide and buffered hydrofluoric, nitric, sulfuric, and hydrofluoric acids; and minimal changes in contact angle after immersion in hexane, hydrochloric acid, photoresist developer, and toluene. Oxygen plasma treatment decreased the contact angle of PDMS2 from 109 degrees to 60 degrees. Exposure to tissue culture media resulted in increased PDMS surface element concentrations of nitrogen and oxygen.

  6. Spectral optimization for micro-CT

    SciTech Connect

    Hupfer, Martin; Nowak, Tristan; Brauweiler, Robert; Eisa, Fabian; Kalender, Willi A.

    2012-06-15

    tube voltage. For 50 mm, voltages larger than 50 kV were preferred. For all three phantom sizes stronger filtration led to notable dose reduction for soft tissue imaging. Validation measurements were found to match simulations well, with deviations being less than 10%. Mouse measurements confirmed simulation results. Conclusions: Optimal photon energies and tube settings strongly depend on both phantom size and imaging task at hand. For in vivo CE imaging and density differences, strong filtration and voltages of 50-65 kV showed good overall results. For soft tissue imaging of animals the size of a rat or larger, voltages higher than 65 kV allow to greatly reduce scan times while maintaining dose efficiency. For imaging of bone structures, usage of only minimum filtration and low tube voltages of 40 kV and below allow exploiting the high contrast of bone at very low energies. Therefore, a combination of two filtrations could prove beneficial for micro-CT: a soft filtration allowing for bone imaging at low voltages, and a variable stronger filtration (e.g., 0.2 mm Cu) for soft tissue and contrast-enhanced imaging.

  7. NEMO educational kit on micro-optics at the secondary school

    NASA Astrophysics Data System (ADS)

    Flores-Arias, M. T.; Bao-Varela, Carmen

    2014-07-01

    NEMO was the "Network of Excellence in Micro-Optics" granted in the "Sixth Framework Program" of the European Union. It aimed at providing Europe with a complete Micro-Optics food-chain, by setting up centers for optical modeling and design; measurement and instrumentation; mastering, prototyping and replication; integration and packaging and reliability and standardization. More than 300 researchers from 30 groups in 12 countries participated in the project. One of the objectives of NEMO was to spread excellence and disseminate knowledge on micro-optics and micro-photonics. To convince pupils, already from secondary school level on, about the crucial role of light and micro-optics and the opportunities this combination holds, several partners of NEMO had collaborate to create this Educational Kit. In Spain the partner involved in this aim was the "Microoptics and GRIN Optics Group" at the University of Santiago of Compostela (USC). The educational kits provided to the Secondary School were composed by two plastic cards with the following microoptical element: different kinds of diffractive optical elements or DOES and refractive optical elements or ROEs namely arrays of micro-lenses. The kit also included a DVD with a handbook for performing the experiments as well as a laser pointer source. This kit was distributed free of charge in the countries with partners in NEMO. In particular in Spain was offered to around 200 Secondary School Centers and only 80 answered accepting evaluate the kit.

  8. Identification of Conserved and Novel MicroRNAs during Tail Regeneration in the Mexican Axolotl.

    PubMed

    Gearhart, Micah D; Erickson, Jami R; Walsh, Andrew; Echeverri, Karen

    2015-01-01

    The Mexican axolotl salamander (Ambystoma mexicanum) is one member of a select group of vertebrate animals that have retained the amazing ability to regenerate multiple body parts. In addition to being an important model system for regeneration, the axolotl has also contributed extensively to studies of basic development. While many genes known to play key roles during development have now been implicated in various forms of regeneration, much of the regulatory apparatus controlling the underlying molecular circuitry remains unknown. In recent years, microRNAs have been identified as key regulators of gene expression during development, in many diseases and also, increasingly, in regeneration. Here, we have used deep sequencing combined with qRT-PCR to undertake a comprehensive identification of microRNAs involved in regulating regeneration in the axolotl. Specifically, among the microRNAs that we have found to be expressed in axolotl tissues, we have identified 4564 microRNA families known to be widely conserved among vertebrates, as well as 59,811 reads of putative novel microRNAs. These findings support the hypothesis that microRNAs play key roles in managing the precise spatial and temporal patterns of gene expression that ensures the correct regeneration of missing tissues.

  9. Identification of Conserved and Novel MicroRNAs during Tail Regeneration in the Mexican Axolotl

    PubMed Central

    Gearhart, Micah D.; Erickson, Jami R.; Walsh, Andrew; Echeverri, Karen

    2015-01-01

    The Mexican axolotl salamander (Ambystoma mexicanum) is one member of a select group of vertebrate animals that have retained the amazing ability to regenerate multiple body parts. In addition to being an important model system for regeneration, the axolotl has also contributed extensively to studies of basic development. While many genes known to play key roles during development have now been implicated in various forms of regeneration, much of the regulatory apparatus controlling the underlying molecular circuitry remains unknown. In recent years, microRNAs have been identified as key regulators of gene expression during development, in many diseases and also, increasingly, in regeneration. Here, we have used deep sequencing combined with qRT-PCR to undertake a comprehensive identification of microRNAs involved in regulating regeneration in the axolotl. Specifically, among the microRNAs that we have found to be expressed in axolotl tissues, we have identified 4564 microRNA families known to be widely conserved among vertebrates, as well as 59,811 reads of putative novel microRNAs. These findings support the hypothesis that microRNAs play key roles in managing the precise spatial and temporal patterns of gene expression that ensures the correct regeneration of missing tissues. PMID:26378530

  10. Micro-CT of rodents: state-of-the-art and future perspectives

    PubMed Central

    Clark, D. P.; Badea, C. T.

    2014-01-01

    Micron-scale computed tomography (micro-CT) is an essential tool for phenotyping and for elucidating diseases and their therapies. This work is focused on preclinical micro-CT imaging, reviewing relevant principles, technologies, and applications. Commonly, micro-CT provides high-resolution anatomic information, either on its own or in conjunction with lower-resolution functional imaging modalities such as positron emission tomography (PET) and single-photon emission computed tomography (SPECT). More recently, however, advanced applications of micro-CT produce functional information by translating clinical applications to model systems (e.g. measuring cardiac functional metrics) and by pioneering new ones (e.g. measuring tumor vascular permeability with nanoparticle contrast agents). The primary limitations of micro-CT imaging are the associated radiation dose and relatively poor soft tissue contrast. We review several image reconstruction strategies based on iterative, statistical, and gradient sparsity regularization, demonstrating that high image quality is achievable with low radiation dose given ever more powerful computational resources. We also review two contrast mechanisms under intense development. The first is spectral contrast for quantitative material discrimination in combination with passive or actively targeted nanoparticle contrast agents. The second is phase contrast which measures refraction in biological tissues for improved contrast and potentially reduced radiation dose relative to standard absorption imaging. These technological advancements promise to develop micro-CT into a commonplace, functional and even molecular imaging modality. PMID:24974176

  11. MicroRNA–mRNA interactions underlying colorectal cancer molecular subtypes

    PubMed Central

    Cantini, Laura; Isella, Claudio; Petti, Consalvo; Picco, Gabriele; Chiola, Simone; Ficarra, Elisa; Caselle, Michele; Medico, Enzo

    2015-01-01

    Colorectal cancer (CRC) transcriptional subtypes have been recently identified by gene expression profiling. Here we describe an analytical pipeline, microRNA master regulator analysis (MMRA), developed to search for microRNAs potentially driving CRC subtypes. Starting from a microRNA–mRNA tumour expression data set, MMRA identifies candidate regulator microRNAs by assessing their subtype-specific expression, target enrichment in subtype mRNA signatures and network analysis-based contribution to subtype gene expression. When applied to a CRC data set of 450 samples, assigned to subtypes by 3 different transcriptional classifiers, MMRA identifies 24 candidate microRNAs, in most cases downregulated in the stem/serrated/mesenchymal (SSM) poor prognosis subtype. Functional validation in CRC cell lines confirms downregulation of the SSM subtype by miR-194, miR-200b, miR-203 and miR-429, which share target genes and pathways mediating this effect. These results show that, by combining statistical tests, target prediction and network analysis, MMRA effectively identifies microRNAs functionally associated to cancer subtypes. PMID:27305450

  12. Identification of Conserved and Novel MicroRNAs during Tail Regeneration in the Mexican Axolotl.

    PubMed

    Gearhart, Micah D; Erickson, Jami R; Walsh, Andrew; Echeverri, Karen

    2015-01-01

    The Mexican axolotl salamander (Ambystoma mexicanum) is one member of a select group of vertebrate animals that have retained the amazing ability to regenerate multiple body parts. In addition to being an important model system for regeneration, the axolotl has also contributed extensively to studies of basic development. While many genes known to play key roles during development have now been implicated in various forms of regeneration, much of the regulatory apparatus controlling the underlying molecular circuitry remains unknown. In recent years, microRNAs have been identified as key regulators of gene expression during development, in many diseases and also, increasingly, in regeneration. Here, we have used deep sequencing combined with qRT-PCR to undertake a comprehensive identification of microRNAs involved in regulating regeneration in the axolotl. Specifically, among the microRNAs that we have found to be expressed in axolotl tissues, we have identified 4564 microRNA families known to be widely conserved among vertebrates, as well as 59,811 reads of putative novel microRNAs. These findings support the hypothesis that microRNAs play key roles in managing the precise spatial and temporal patterns of gene expression that ensures the correct regeneration of missing tissues. PMID:26378530

  13. Micro-agglomerate flotation for deep cleaning of coal. Final report

    SciTech Connect

    Chander, S.; Hogg, R.

    1997-01-15

    The development of practical technologies for the deep cleaning of coal has been seriously hampered by the problems of carrying out efficient coal/mineral separations at the very fine sizes (often finer than 10 {micro}m) needed to achieve adequate liberation of the mineral matter from the coal matrix. In this investigation a hybrid process--Micro-agglomerate flotation--which is a combination of oil-agglomeration and froth flotation was studied. The basic concept is to use small quantities of oil to promote the formation of dense micro-agglomerates with minimal entrapment of water and mineral particles and to use froth flotation to separate these micro-agglomerates from the water/dispersed-mineral phase. Since the floating units will be relatively large agglomerates (30--50 {micro}m in size) rather than fine coal particles (1--10 {micro}m) the problems of froth overload and water/mineral carryover should be significantly alleviated. There are, however, complications. The process involves at least five phases: two or more solids (coal and mineral), two liquids (oil and water) and one gas (air). It is demonstrated in this study that the process is very sensitive to fluctuations in operating parameters. It is necessary to maintain precise control over the chemistry of the liquid phases as well as the agitation conditions in order to promote selectivity. Both kinetics as well as thermodynamic factors play a critical role in determining overall system response.

  14. Science with Micro-X: the TES Microcalorimeter X-ray Imaging Rocket

    SciTech Connect

    Figueroa-Feliciano, E; Bandler, S R; Bautz, M; Boyce, K R; Brown, G V; Deiker, S; Doriese, W B; Flanagan, K; Galeazzi, M; Hilton, G C; Hwang, U; Irwin, K D; Kallman, T; Kelley, R L; Kilbourne, C A; Kissel, S; Levine, A; Loewenstein, M; Martinez-Galarce, D; McCammon, D; Mushotzky, R; Petre, R; Porter, F S; Reistema, C D; Saab, T; Serlemitsos, P; Schulz, N; Smith, R; Ullom, J N

    2006-05-16

    Micro-X is a proposed sounding rocket experiment that will combine a transition-edge-sensor X-ray-microcalorimeter array with a conical imaging mirror to obtain high-spectral-resolution images of extended and point X-ray sources. We describe the payload and the science targeted by this mission including the discussion of three possible Micro-X targets: the Puppis A supernova remnant, the Virgo Cluster, and Circinus X-1. For example, a Micro-X observation of the bright eastern knot of Puppis A will obtain a line-dominated spectrum with 90,000 counts collected in 300 seconds at 2 eV resolution across the 0.3-2.5 keV band. Micro-X will utilize plasma diagnostics to determine the thermodynamic and ionization state of the plasma, to search for line shifts and broadening associated with dynamical processes, and seek evidence of ejecta enhancement. For clusters of galaxies, Micro-X can uniquely study turbulence and the temperature distribution function. For binaries, Micro-X's high resolution spectra will separate the different processes contributing to the Fe K lines at 6 keV and give a clear view of the geometry of the gas flows and circumstellar gas.

  15. Nanofocusing enhancement in a tapered slit by using a dielectric micro isosceles triangle prism and tuning the entrance aperture

    NASA Astrophysics Data System (ADS)

    Kuang, Dengfeng; Ouyang, Sheng; Du, Zhongxun

    2012-07-01

    We present a combined configuration consisting of a dielectric micro isosceles triangular prism and a metallic tapered slit for enhanced nanofocusing. The dielectric micro isosceles triangular prism collects the incident light first and then the tapered slit guides the beam to form naofocusing with higher intensity at the exit aperture of the tapered slit, which overcomes the limit of the extremely small entrance aperture diaphragm of the slit. With the help of the dielectric micro isosceles triangular prism, the intensity of the nanofocused electric field at the exit aperture of the tapered slit can be increased more than 4 folds.

  16. Room temperature scanning Hall probe microscopy using GaAs/AlGaAs and Bi micro-hall probes.

    PubMed

    Sandhu, A; Masuda, H; Oral, A; Bending, S J; Yamada, A; Konagai, M

    2002-05-01

    A room temperature scanning Hall probe microscope system utilizing GaAs/AlGaAs and bismuth micro-Hall probes was used for magnetic imaging of ferromagnetic domain structures on the surfaces of crystalline thin film garnets and permanent magnets. The Bi micro-Hall probes had dimensions ranging between 0.25 and 2.8 microm2 and were fabricated using a combination of optical lithography and focused ion beam milling. The use of bismuth was found to overcome surface depletion effects associated with semiconducting micro-Hall probes. Our experiments demonstrated that Bi is a practical choice of material for fabricating sub-micron sized Hall sensors.

  17. An overview of micro-optical components and system technology: bulk, planar, and thin-film for laser initiated devices

    NASA Astrophysics Data System (ADS)

    Lizotte, Todd

    2010-08-01

    There are a number of attractive micro optical elements or combinations of elements that are currently used or could be employed in optically initiated ordnance systems. When taking a broad-spectrum examination of optically initiated devices, the required key parameters become obviously straightforward for micro optics. Plainly stated, micro optics need to be simple, inexpensive, reliable, robust and compatible within their operational environment. This presentation focuses on the variety of optical elements and components available in the market place today that could be used to realize micro-optical beam shaping and delivery systems for optically initiated devices. A number of micro optical elements will be presented with specific bulk, planar optical and thin film optical devices, such as diffractive optics, micro prisms, axicons, waveguides, micro lenses, beam splitters and gratings. Further descriptions will be presented on the subject of coupling light from a laser beam into a multimode optical fiber. The use of micro optics for collimation of the laser source and conditioning of the laser beam to achieve the highest efficiency and matching the optical fiber NA will be explained. An emphasis on making these optical assemblies compact and rugged will be highlighted.

  18. Deep sequencing and proteomic analysis of the microRNA-induced silencing complex in human red blood cells.

    PubMed

    Azzouzi, Imane; Moest, Hansjoerg; Wollscheid, Bernd; Schmugge, Markus; Eekels, Julia J M; Speer, Oliver

    2015-05-01

    During maturation, erythropoietic cells extrude their nuclei but retain their ability to respond to oxidant stress by tightly regulating protein translation. Several studies have reported microRNA-mediated regulation of translation during terminal stages of erythropoiesis, even after enucleation. In the present study, we performed a detailed examination of the endogenous microRNA machinery in human red blood cells using a combination of deep sequencing analysis of microRNAs and proteomic analysis of the microRNA-induced silencing complex. Among the 197 different microRNAs detected, miR-451a was the most abundant, representing more than 60% of all read sequences. In addition, miR-451a and its known target, 14-3-3ζ mRNA, were bound to the microRNA-induced silencing complex, implying their direct interaction in red blood cells. The proteomic characterization of endogenous Argonaute 2-associated microRNA-induced silencing complex revealed 26 cofactor candidates. Among these cofactors, we identified several RNA-binding proteins, as well as motor proteins and vesicular trafficking proteins. Our results demonstrate that red blood cells contain complex microRNA machinery, which might enable immature red blood cells to control protein translation independent of de novo nuclei information. PMID:25681748

  19. Exploring associations between micro-level models of innovation diffusion and emerging macro-level adoption patterns

    NASA Astrophysics Data System (ADS)

    Laciana, Carlos E.; Rovere, Santiago L.; Podestá, Guillermo P.

    2013-04-01

    A micro-level agent-based model of innovation diffusion was developed that explicitly combines (a) an individual's perception of the advantages or relative utility derived from adoption, and (b) social influence from members of the individual's social network. The micro-model was used to simulate macro-level diffusion patterns emerging from different configurations of micro-model parameters. Micro-level simulation results matched very closely the adoption patterns predicted by the widely-used Bass macro-level model (Bass, 1969 [1]). For a portion of the p-q domain, results from micro-simulations were consistent with aggregate-level adoption patterns reported in the literature. Induced Bass macro-level parameters p and q responded to changes in micro-parameters: (1) p increased with the number of innovators and with the rate at which innovators are introduced; (2) q increased with the probability of rewiring in small-world networks, as the characteristic path length decreases; and (3) an increase in the overall perceived utility of an innovation caused a corresponding increase in induced p and q values. Understanding micro to macro linkages can inform the design and assessment of marketing interventions on micro-variables-or processes related to them-to enhance adoption of future products or technologies.

  20. Design of a holographic micro-scale spectrum-splitting photovoltaic system

    NASA Astrophysics Data System (ADS)

    Wu, Yuechen; Vorndran, Shelby; Ayala Pelaez, Silvana; Russo, Juan M.; Kostuk, Raymond K.

    2015-09-01

    Micro-scale PV technology combines the high conversion efficiency of concentrated photovoltaics (CPV) with the low costs and the simple form of flat panel PV. Some of the benefits of micro-scale PV include: reduced semiconductor material usage; improved heat rejection capacity; and more versatile PV cell interconnect configurations. Spectrumsplitting is also a beneficial technique to increase the efficiency and reduce the cost of photovoltaic systems. It spatially separates the incident solar spectrum into spectral components and directs them to PV cells with matching bandgaps. This approach avoids the current and lattice matching problems that exist in tandem multi-junction systems. In this paper, we applied the ideas of spectrum-splitting in a micro-scale PV system, and demonstrated a holographic micro-scale spectrum-splitting photovoltaic system. This system consists of a volume transmission hologram in combination with a micro-lens array. An analysis methodology was developed to design the system and determine the performance of the resulting system. The spatial characteristics of the dispersed spectrum, the overall system conversion efficiency, and the improvement over best bandgap will be discussed.

  1. Effects of Micro-Vibratory Modulation during Robot-Assisted Membrane Peeling*

    PubMed Central

    Gonenc, Berk; Gehlbach, Peter; Taylor, Russell H.; Iordachita, Iulian

    2016-01-01

    In retinal microsurgery, membrane peeling is a standard procedure requiring the delamination of a thin fibrous membrane adherent to the retina surface by applying very small forces. Robotic devices with combined force-sensing instruments have significant potential to assist this procedure by facilitating membrane delamination through induced micro-vibrations. However, defining the optimal frequency and amplitude for generating such vibrations, and updating these parameters during the procedure is not trivial. Automatic adjustment of these parameters via an adaptive control scheme is possible only if the individual parameter effects on delamination behavior are known. This study presents an experimental exploration of how micro-vibration amplitude and frequency affect membrane peeling forces alone. Combining a micromanipulator and a force-sensing micro-forceps, several peeling experiments were done on artificial phantoms (bandages) and inner shell membrane of raw chicken eggs. In the tested range of micro-vibration frequencies (10-50 Hz) the average delamination force was minimized mostly at 30 Hz for the bandages and at 50 Hz for the egg membranes. Increasing the micro-vibration amplitude from 50 μm up to 150 μm provided further reduction in average force, thus facilitated membrane delamination. PMID:27110431

  2. Sensitive detection of melanoma metastasis using circulating microRNA expression profiles.

    PubMed

    Shiiyama, Rie; Fukushima, Satoshi; Jinnin, Masatoshi; Yamashita, Junji; Miyashita, Azusa; Nakahara, Satoshi; Kogi, Ai; Aoi, Jun; Masuguchi, Shinichi; Inoue, Yuji; Ihn, Hironobu

    2013-10-01

    Numerous studies have indicated that the serum levels of microRNAs are useful for the diagnosis or evaluation of activity in human diseases. However, determining the level of only one of the nearly 2000 microRNAs identified so far may be less significant. Accordingly, we examined the possibility that the expression pattern of multiple microRNAs in each patient may be a more reliable disease marker for melanoma, especially metastatic disease, focusing on the interaction among microRNAs. Six microRNAs (miR-9, miR-145, miR-150, miR-155, miR-203, and miR-205) were evaluated using real-time PCR in 11 patients with metastatic melanoma and in 16 patients without melanoma. The expression of the six microRNAs was significantly different between the patients with metastasis and those without it. MiR-9 and miR-205 and miR-203 and miR-205 showed significant correlations, and the combination of miR-9, miR-145, miR-150, miR-155, and miR-205 was more sensitive than when each miR was used individually to distinguish the patients with metastasis from those without it. This is the first report demonstrating the expression profiles of multiple microRNAs in melanoma patients. Clarifying the involvement of the microRNA network in the pathogenesis of melanoma may contribute to the development of new diagnostic tools and to advancing the understanding of this disease.

  3. A novel dual-detector micro-spectrometer

    NASA Astrophysics Data System (ADS)

    Otto, Thomas; Saupe, Ray; Stock, Volker; Bruch, Reinhard; Gruska, Bernd; Gessner, Thomas

    2005-01-01

    Infrared analysis is a well-established tool for measuring composition and purity of various materials in industrial-, medical- and environmental applications. Traditional spectrometers, for example Fourier Transform Infrared (FTIR) Instruments are mainly designed for laboratory use and are generally, too large, heavy, costly and delicate to handle for remote applications. With important advances in the miniaturization, ruggedness and cost efficiency we have designed and created a new type of a micromirror spectrometer that can operate in harsh temperature and vibrating environments This device is ideally suited for environmental monitoring, chemical and biological applications as well as detection of biological warfare agents and sensing in important security locations In order to realize such compact, portable and field-deployable spectrometers we have applied MOEMS technology. Thus our novel dual detector micro mirror system is composed of a scanning micro mirror combined with a diffraction grating and other essential optical components in order to miniaturize the basic modular set-up. Especially it periodically disperses polychromatic radiation into its spectral components, which are measured by a combination of a visible (VIS) and near infrared (NIR) single element detector. By means of integrated preamplifiers high-precise measurements over a wide dynamic wavelength range are possible. In addition the spectrometer, including the radiation source, detectors and electronics can be coupled to a minimum-volume liquid or gas-flow cell. Furthermore a SMA connector as a fiber optical input allows easy attachment of fiber based probes. By utilizing rapid prototyping techniques, where all components are directly integrated, the micro mirror spectrometer is manufactured for the 700-1700 nm spectral range. In this work the advanced optical design and integration of the electronic interface will be reviewed. Furthermore we will demonstrate the performance of the system

  4. Formability of Micro-Tubes in Hydroforming

    NASA Astrophysics Data System (ADS)

    Hartl, Christoph; Anyasodor, Gerald; Lungershausen, Joern

    2011-05-01

    Micro-hydroforming is a down-scaled metal forming process, based on the expansion of micro-tubes by internal pressurization within a die cavity. The objective of micro-hydroforming is to provide a technology for the economic mass production of complex shaped hollow micro-components. Influence of size effects in metal forming processes increases with scaling down of metal parts. Investigations into the change in formability of micro-tubes due to metal part scaling down constituted an important subject within the conducted fundamental research work. Experimental results are presented, concerning the analysis of the formability of micro-tubes made from stainless steel AISI 304 with an outer diameter of 800 μm and a wall thickness of 40 μm. An average ratio of tube wall thickness to grain size of 1.54 of up to 2.56 was analyzed. Miniaturised mechanical standard methods as well as bulge tests with internal hydrostatic pressurization of the tubular specimens were applied to analyze the influence of size-dependent effects. A test device was developed for the bulge experiments which enabled the pressurization of micro-tubes with internal pressures up to 4000 bar. To determine the attainable maximum achievable expansion ratio the tubes were pressurized in the bulge tests with increasing internal pressure until instability due to necking and subsequent bursting occurred. Comparisons with corresponding tests of macro-tubes, made from the here investigated material, showed a change in formability of micro-tubes which was attributed to the scaling down of the hydroforming process. In addition, a restricted applicability of existing theoretical correlations for the determination of the maximum pressure at bursting was observed for down-scaled micro-hydroforming.

  5. Dual-energy micro-CT imaging of pulmonary airway obstruction: correlation with micro-SPECT

    NASA Astrophysics Data System (ADS)

    Badea, C. T.; Befera, N.; Clark, D.; Qi, Y.; Johnson, G. A.

    2014-03-01

    To match recent clinical dual energy (DE) CT studies focusing on the lung, similar developments for DE micro-CT of the rodent lung are required. Our group has been actively engaged in designing pulmonary gating techniques for micro- CT, and has also introduced the first DE micro-CT imaging method of the rodent lung. The aim of this study was to assess the feasibility of DE micro-CT imaging for the evaluation of airway obstruction in mice, and to compare the method with micro single photon emission computed tomography (micro-SPECT) using technetium-99m labeled macroaggregated albumin (99mTc-MAA). The results suggest that the induced pulmonary airway obstruction causes either atelectasis, or air-trapping similar to asthma or chronic bronchitis. Atelectasis could only be detected at early time points in DE micro-CT images, and is associated with a large increase in blood fraction and decrease in air fraction. Air trapping had an opposite effect with larger air fraction and decreased blood fraction shown by DE micro-CT. The decrease in perfusion to the hypoventilated lung (hypoxic vasoconstriction) is also seen in micro-SPECT. The proposed DE micro-CT technique for imaging localized airway obstruction performed well in our evaluation, and provides a higher resolution compared to micro-SPECT. Both DE micro-CT and micro-SPECT provide critical, quantitative lung biomarkers for image-based anatomical and functional information in the small animal. The methods are readily linked to clinical methods allowing direct comparison of preclinical and clinical results.

  6. Raman Spectroscopy of Optically Trapped Single Biological Micro-Particles

    PubMed Central

    Redding, Brandon; Schwab, Mark J.; Pan, Yong-le

    2015-01-01

    The combination of optical trapping with Raman spectroscopy provides a powerful method for the study, characterization, and identification of biological micro-particles. In essence, optical trapping helps to overcome the limitation imposed by the relative inefficiency of the Raman scattering process. This allows Raman spectroscopy to be applied to individual biological particles in air and in liquid, providing the potential for particle identification with high specificity, longitudinal studies of changes in particle composition, and characterization of the heterogeneity of individual particles in a population. In this review, we introduce the techniques used to integrate Raman spectroscopy with optical trapping in order to study individual biological particles in liquid and air. We then provide an overview of some of the most promising applications of this technique, highlighting the unique types of measurements enabled by the combination of Raman spectroscopy with optical trapping. Finally, we present a brief discussion of future research directions in the field. PMID:26247952

  7. Organic Micro/Nanoscale Lasers.

    PubMed

    Zhang, Wei; Yao, Jiannian; Zhao, Yong Sheng

    2016-09-20

    Micro/nanoscale lasers that can deliver intense coherent light signals at (sub)wavelength scale have recently captured broad research interest because of their potential applications ranging from on-chip information processing to high-throughput sensing. Organic molecular materials are a promising kind of ideal platform to construct high-performance microlasers, mainly because of their superiority in abundant excited-state processes with large active cross sections for high gain emissions and flexibly assembled structures for high-quality microcavities. In recent years, ever-increasing efforts have been dedicated to developing such organic microlasers toward low threshold, multicolor output, broadband tunability, and easy integration. Therefore, it is increasingly important to summarize this research field and give deep insight into the structure-property relationships of organic microlasers to accelerate the future development. In this Account, we will review the recent advances in organic miniaturized lasers, with an emphasis on tunable laser performances based on the tailorable microcavity structures and controlled excited-state gain processes of organic materials toward integrated photonic applications. Organic π-conjugated molecules with weak intermolecular interactions readily assemble into regular nanostructures that can serve as high-quality optical microcavities for the strong confinement of photons. On the basis of rational material design, a series of optical microcavities with different structures have been controllably synthesized. These microcavity nanostructures can be endowed with effective four-level dynamic gain processes, such as excited-state intramolecular charge transfer, excited-state intramolecular proton transfer, and excimer processes, that exhibit large dipole optical transitions for strongly active gain behaviors. By tailoring these excited-state processes with molecular/crystal engineering and external stimuli, people have effectively

  8. Micro-sonicator for spore lysis

    DOEpatents

    Miles, Robin R.; Belgrader, Phillip; Nasarabadi, Shanavaz L.

    2000-01-01

    A micro-sonicator for spore lysis. Using micromachining technology, the micro-sonicator uses ultrasonic excitation of spores to perform spore and cell lysis. The micro-sonicator comprises a container with a cavity therein for retaining the sample in an ultrasonic transmission medium, the cavity being closed by a silicon membrane to which an electrode and piezoelectric material are attached, with the electrode and piezoelectric material being electrically connected to an AC signal generator which causes the membrane to flex and vibrate at the frequency of the applied voltage.

  9. Micro turbine engines for drones propulsion

    NASA Astrophysics Data System (ADS)

    Dutczak, J.

    2016-09-01

    Development of micro turbine engines began from attempts of application of that propulsion source by group of enthusiasts of aviation model making. Nowadays, the domain of micro turbojet engines is treated on a par with “full size” aviation constructions. The dynamic development of these engines is caused not only by aviation modellers, but also by use of micro turbojet engines by army to propulsion of contemporary drones, i.e. Unmanned Aerial Vehicles (UAV) or Unmanned Aerial Systems (UAS). On the base of selected examples the state of art in the mentioned group of engines has been presented in the article.

  10. Materials micro-processing using femtosecond lasers

    NASA Astrophysics Data System (ADS)

    Dabu, R.; Zamfirescu, M.; Anghel, I.; Jipa, F.

    2013-06-01

    Nonlinear optical phenomena which dominate the interaction of tightly focused femtosecond laser beams with materials are discussed. Different femtosecond laser based techniques for material processing such as laser ablation, two-photon photo-polymerization, and material surface nano-structuring are described. For the computer controlled micro-processing of materials, near-infrared Ti:sapphire femtosecond lasers, with nano-Joule/micro-Joule pulse energy, were coupled with direct laser writing workstations. Laser fabricated micro-nanostructures and their applications are presented.

  11. Advanced packaging for Integrated Micro-Instruments

    NASA Technical Reports Server (NTRS)

    Lyke, James L.

    1995-01-01

    The relationship between packaging, microelectronics, and micro-electrical-mechanical systems (MEMS) is an important one, particularly when the edges of performance boundaries are pressed, as in the case of miniaturized systems. Packaging is a sort of physical backbone that enables the maximum performance of these systems to be realized, and the penalties imposed by conventional packing approaches is particularly limiting for MEMS devices. As such, advanced packaging approaches, such as multi-chip modules (MCM's) have been touted as a true means of electronic 'enablement' for a variety of application domains. Realizing an optimum system of packaging, however, in not as simple as replacing a set of single chip packages with a substrate of interconnections. Research at Phillips Laboratory has turned up a number of integrating options in the two- and three-dimensional rending of miniature systems with physical interconnection structures with intrinsically high performance. Not only do these structures motivate the redesign of integrated circuits (IC's) for lower power, but they possess interesting features that provide a framework for the direct integration of MEMS devices. Cost remains a barrier to the application of MEMS devices, even in space systems. Several innovations are suggested that will result in lower cost and more rapid cycle time. First, the novelty of a 'constant floor plan' MCM which encapsulates a variety of commonly used components into a stockable, easily customized assembly is discussed. Next, the use of low-cost substrates is examined. The anticipated advent of ultra-high density interconnect (UHDI) is suggested as the limit argument of advanced packaging. Finally, the concept of a heterogeneous 3-D MCM system is outlined that allows for the combination of different compatible packaging approaches into a uniformly dense structure that could also include MEMS-based sensors.

  12. Snow Micro-Structure Model

    2014-06-25

    PIKA is a MOOSE-based application for modeling micro-structure evolution of seasonal snow. The model will be useful for environmental, atmospheric, and climate scientists. Possible applications include application to energy balance models, ice sheet modeling, and avalanche forecasting. The model implements physics from published, peer-reviewed articles. The main purpose is to foster university and laboratory collaboration to build a larger multi-scale snow model using MOOSE. The main feature of the code is that it is implementedmore » using the MOOSE framework, thus making features such as multiphysics coupling, adaptive mesh refinement, and parallel scalability native to the application. PIKA implements three equations: the phase-field equation for tracking the evolution of the ice-air interface within seasonal snow at the grain-scale; the heat equation for computing the temperature of both the ice and air within the snow; and the mass transport equation for monitoring the diffusion of water vapor in the pore space of the snow.« less

  13. Snow Micro-Structure Model

    SciTech Connect

    Micah Johnson, Andrew Slaughter

    2014-06-25

    PIKA is a MOOSE-based application for modeling micro-structure evolution of seasonal snow. The model will be useful for environmental, atmospheric, and climate scientists. Possible applications include application to energy balance models, ice sheet modeling, and avalanche forecasting. The model implements physics from published, peer-reviewed articles. The main purpose is to foster university and laboratory collaboration to build a larger multi-scale snow model using MOOSE. The main feature of the code is that it is implemented using the MOOSE framework, thus making features such as multiphysics coupling, adaptive mesh refinement, and parallel scalability native to the application. PIKA implements three equations: the phase-field equation for tracking the evolution of the ice-air interface within seasonal snow at the grain-scale; the heat equation for computing the temperature of both the ice and air within the snow; and the mass transport equation for monitoring the diffusion of water vapor in the pore space of the snow.

  14. MicroRNA and Metastasis.

    PubMed

    Ma, L

    2016-01-01

    Noncoding RNAs are important regulatory molecules of cellular processes. MicroRNAs (miRNAs) are small noncoding RNAs that bind to complementary sequences in the 3' untranslated region of target mRNAs, leading to degradation of the target mRNAs and/or inhibition of their translation. Some miRNAs are essential for normal animal development; however, many other miRNAs are dispensable for development but play a critical role in pathological conditions, including tumorigenesis and metastasis. miRNA genes often reside at fragile chromosome sites and are deregulated in cancer. Some miRNAs function as oncogenes or tumor suppressors, collectively termed "oncomirs." Specific metastasis-regulating miRNAs, collectively termed "metastamirs," govern molecular processes and pathways in malignant progression in either a tumor cell-autonomous or a cell-nonautonomous manner. Recently, exosome-transferred miRNAs have emerged as mediators of the tumor-stroma cross talk. In this chapter, we focus on the functions, mechanisms of action, and therapeutic potential of miRNAs, particularly oncomirs and metastamirs. PMID:27613133

  15. Micro Sun Sensor for Spacecraft

    NASA Technical Reports Server (NTRS)

    Mobasser, Sohrab; Liebe, Carl; Bae, Youngsam; Schroeder, Jeffrey; Wrigley, Chris

    2004-01-01

    A report describes the development of a compact micro Sun sensor for use as a part of the attitude determination subsystem aboard future miniature spacecraft and planetary robotic vehicles. The prototype unit has a mass of only 9 g, a volume of only 4.2 cm(sup 3), a power consumption of only 30 mW, and a 120 degree field of view. The unit has demonstrated an accuracy of 1 arcminute. The unit consists of a multiple pinhole camera: A micromachined mask containing a rectangular array of microscopic pinholes, machined utilizing the microectromechanical systems (MEMS), is mounted in front of an active-pixel sensor (APS) image detector. The APS consists of a 512 x 512-pixel array, on-chip 10-bit analog to digital converter (ADC), on-chip bias generation, and on-chip timing control for self-sequencing and easy programmability. The digitized output of the APS is processed to compute the centroids of the pinhole Sun images on the APS. The Sun angle, relative to a coordinate system fixed to the sensor unit, is then computed from the positions of the centroids.

  16. The microRNA Machinery.

    PubMed

    Roberts, Thomas C

    2015-01-01

    MicroRNAs (miRNAs) are short (~22 nucleotides) single-stranded RNA molecules that primarily function to negatively regulate gene expression at the post-transcriptional level. miRNAs have thus been implicated in the regulation of a wide variety of normal cell functions and pathophysiological conditions. The miRNA machinery consists of a series of protein complexes which act to: (1) cleave the precursor-miRNA hairpin from its primary transcript (i.e. DROSHA and DGCR8); (2) traffic the miRNA hairpin between nucleus and cytoplasm (i.e. XPO5); (3) remove the loop sequence of the hairpin by a second nucleolytic cleavage reaction (i.e. DICER1); (4) facilitate loading of the mature miRNA sequence into an Argonaute protein (typically AGO2) as part of the RNA-Induced Silencing Complex (RISC); (5) guide the loaded RISC complex to complementary, or semi-complementary, target transcripts and (6) facilitate gene silencing via one of several possible mechanisms. PMID:26662984

  17. Nanowire-integrated microporous silicon membrane for continuous fluid transport in micro cooling device

    SciTech Connect

    So, Hongyun; Pisano, Albert P.; Cheng, Jim C.

    2013-10-14

    We report an efficient passive micro pump system combining the physical properties of nanowires and micropores. This nanowire-integrated microporous silicon membrane was created to feed coolant continuously onto the surface of the wick in a micro cooling device to ensure it remains hydrated and in case of dryout, allow for regeneration of the system. The membrane was fabricated by photoelectrochemical etching to form micropores followed by hydrothermal growth of nanowires. This study shows a promising approach to address thermal management challenges for next generation electronic devices with absence of external power.

  18. MicroBooNE: A New Liquid Argon Time Projection Chamber Experiment

    SciTech Connect

    Soderberg, M.

    2009-10-01

    Liquid Argon Time Projection Chamber detectors are well suited to study neutrino interactions, and are an intriguing option for future massive detectors capable of measuring the parameters that characterize neutrino oscillations. These detectors combine fine-grained tracking with calorimetry, allowing for excellent imaging and particle identification ability. In this talk the details of the MicroBooNE experiment, a 175 ton LArTPC which will be exposed to Fermilab's Booster Neutrino Beamline starting in 2011, will be presented. The ability of MicroBooNE to differentiate electrons from photons gives the experiment unique capabilities in low energy neutrino interaction measurements.

  19. Hypertelorism and micro-orbit simultaneous correction in a patient with paramedian bilateral facial clefts.

    PubMed

    Prada, José Rolando; Mendoza, María Bibiana

    2014-09-01

    The aim of this paper is to report a case of a patient with paramedian bilateral facial clefts and hypertelorism associated with a severe encephalocele and micro-orbit. The patient required a facial bipartition to correct a transsphenoidal encephalocele, and a modified medialization surgery of the orbits to simultaneously expand the micro-orbit and correct the hypertelorism. These procedures achieved hypertelorbitism correction, orbital expansion which allowed symmetrical facial growth, and a functional orbit that permitted the use of an ocular prosthesis. We present this unique case to highlight the predictable results of a procedure that combines 2 surgical reproducible techniques of craniofacial surgery.

  20. Strain response of stretchable micro-electrodes: Controlling sensitivity with serpentine designs and encapsulation

    SciTech Connect

    Gutruf, Philipp; Walia, Sumeet; Nur Ali, Md; Sriram, Sharath E-mail: madhu.bhaskaran@gmail.com; Bhaskaran, Madhu E-mail: madhu.bhaskaran@gmail.com

    2014-01-13

    The functionality of flexible electronics relies on stable performance of thin film micro-electrodes. This letter investigates the behavior of gold thin films on polyimide, a prevalent combination in flexible devices. The dynamic behavior of gold micro-electrodes has been studied by subjecting them to stress while monitoring their resistance in situ. The shape of the electrodes was systematically varied to examine resistive strain sensitivity, while an additional encapsulation was applied to characterize multilayer behavior. The realized designs show remarkable tolerance to repetitive strain, demonstrating that curvature and encapsulation are excellent approaches for minimizing resistive strain sensitivity to enable durable flexible electronics.

  1. Self-Transport of Condensed Liquid in Micro Cooling Device Using Distributed Meniscus Pumping.

    PubMed

    So, Hongyun; Pisano, Albert P

    2015-06-16

    This paper reports a reliable passive micro pump system combining the physical properties of a tapered microchannel and sharp microstructures. This tailored microchannel with triple-spike microstructures was created to transport condensed liquid into the reservoir chamber in a micro cooling device and in the case of chip off-mode prepare the next cooling cycle before chip on-mode, allowing the reliable and continuous circulation of coolant without liquid being trapped in the vapor channel causing dryout limitation. At the tapered channel end, the pinned liquid meniscus was distributed by a middle spike and then continued to overflow into the condenser chamber due to extended capillary action. PMID:26010771

  2. Self-Transport of Condensed Liquid in Micro Cooling Device Using Distributed Meniscus Pumping.

    PubMed

    So, Hongyun; Pisano, Albert P

    2015-06-16

    This paper reports a reliable passive micro pump system combining the physical properties of a tapered microchannel and sharp microstructures. This tailored microchannel with triple-spike microstructures was created to transport condensed liquid into the reservoir chamber in a micro cooling device and in the case of chip off-mode prepare the next cooling cycle before chip on-mode, allowing the reliable and continuous circulation of coolant without liquid being trapped in the vapor channel causing dryout limitation. At the tapered channel end, the pinned liquid meniscus was distributed by a middle spike and then continued to overflow into the condenser chamber due to extended capillary action.

  3. Micro-Analyzer: automatic preprocessing of Affymetrix microarray data.

    PubMed

    Guzzi, Pietro Hiram; Cannataro, Mario

    2013-08-01

    A current trend in genomics is the investigation of the cell mechanism using different technologies, in order to explain the relationship among genes, molecular processes and diseases. For instance, the combined use of gene-expression arrays and genomic arrays has been demonstrated as an effective instrument in clinical practice. Consequently, in a single experiment different kind of microarrays may be used, resulting in the production of different types of binary data (images and textual raw data). The analysis of microarray data requires an initial preprocessing phase, that makes raw data suitable for use on existing analysis platforms, such as the TIGR M4 (TM4) Suite. An additional challenge to be faced by emerging data analysis platforms is the ability to treat in a combined way those different microarray formats coupled with clinical data. In fact, resulting integrated data may include both numerical and symbolic data (e.g. gene expression and SNPs regarding molecular data), as well as temporal data (e.g. the response to a drug, time to progression and survival rate), regarding clinical data. Raw data preprocessing is a crucial step in analysis but is often performed in a manual and error prone way using different software tools. Thus novel, platform independent, and possibly open source tools enabling the semi-automatic preprocessing and annotation of different microarray data are needed. The paper presents Micro-Analyzer (Microarray Analyzer), a cross-platform tool for the automatic normalization, summarization and annotation of Affymetrix gene expression and SNP binary data. It represents the evolution of the μ-CS tool, extending the preprocessing to SNP arrays that were not allowed in μ-CS. The Micro-Analyzer is provided as a Java standalone tool and enables users to read, preprocess and analyse binary microarray data (gene expression and SNPs) by invoking TM4 platform. It avoids: (i) the manual invocation of external tools (e.g. the Affymetrix Power

  4. Micro-Analyzer: automatic preprocessing of Affymetrix microarray data.

    PubMed

    Guzzi, Pietro Hiram; Cannataro, Mario

    2013-08-01

    A current trend in genomics is the investigation of the cell mechanism using different technologies, in order to explain the relationship among genes, molecular processes and diseases. For instance, the combined use of gene-expression arrays and genomic arrays has been demonstrated as an effective instrument in clinical practice. Consequently, in a single experiment different kind of microarrays may be used, resulting in the production of different types of binary data (images and textual raw data). The analysis of microarray data requires an initial preprocessing phase, that makes raw data suitable for use on existing analysis platforms, such as the TIGR M4 (TM4) Suite. An additional challenge to be faced by emerging data analysis platforms is the ability to treat in a combined way those different microarray formats coupled with clinical data. In fact, resulting integrated data may include both numerical and symbolic data (e.g. gene expression and SNPs regarding molecular data), as well as temporal data (e.g. the response to a drug, time to progression and survival rate), regarding clinical data. Raw data preprocessing is a crucial step in analysis but is often performed in a manual and error prone way using different software tools. Thus novel, platform independent, and possibly open source tools enabling the semi-automatic preprocessing and annotation of different microarray data are needed. The paper presents Micro-Analyzer (Microarray Analyzer), a cross-platform tool for the automatic normalization, summarization and annotation of Affymetrix gene expression and SNP binary data. It represents the evolution of the μ-CS tool, extending the preprocessing to SNP arrays that were not allowed in μ-CS. The Micro-Analyzer is provided as a Java standalone tool and enables users to read, preprocess and analyse binary microarray data (gene expression and SNPs) by invoking TM4 platform. It avoids: (i) the manual invocation of external tools (e.g. the Affymetrix Power

  5. Study of Selecting on Light Source Used for Micro-algae Cultivation in Space

    NASA Astrophysics Data System (ADS)

    Ai, Weidang; Ai, Weidang; Guo, Shuang-Sheng; Gao, Feng; Tang, Yong-Kang; Qin, Li-Feng

    To select suitable light source for micro-algae cultivation in future space station, the selected Spirulina plastensis(No.7) were cultured under different lightening qualities, including six light sources that were made up of different combinations of red and blue light-emitting diode(LED). The growth, photosynthetic efficiency and nutrition quality of the Spirulina, were analyzed. From the experiments, the red light may promote the cumulation of biomass of the Spirulina, and the cumulating rate was the highest under all red light source, but the syntheses of protein, phycobiliprotein, β-carotene, VE and other nutrients needs a certain portion of blue light; yet, the complete blue light condition is not favorable to the growth of Spirulina, and may bring pollution by chlorella and other kinds of micro-algae. It is concluded that the LEDs can be used as the light resource of micro-algae cultivation. The normal growth and development of microalgae need two light sources of both red and blue LEDs. The comprehensive analyses of the various factors that affect the growth of Spirulina, such as nutrition quality and photosynthetic activities, etc., showed that the combination of 80% red and 20% blue LED is the optimum one among those tested combinations. Key word: light-emitting diode; micro-algae; controlled ecological life support system (CELSS); space cultivation

  6. Micro benchtop optics by bulk silicon micromachining

    DOEpatents

    Lee, Abraham P.; Pocha, Michael D.; McConaghy, Charles F.; Deri, Robert J.

    2000-01-01

    Micromachining of bulk silicon utilizing the parallel etching characteristics of bulk silicon and integrating the parallel etch planes of silicon with silicon wafer bonding and impurity doping, enables the fabrication of on-chip optics with in situ aligned etched grooves for optical fibers, micro-lenses, photodiodes, and laser diodes. Other optical components that can be microfabricated and integrated include semi-transparent beam splitters, micro-optical scanners, pinholes, optical gratings, micro-optical filters, etc. Micromachining of bulk silicon utilizing the parallel etching characteristics thereof can be utilized to develop miniaturization of bio-instrumentation such as wavelength monitoring by fluorescence spectrometers, and other miniaturized optical systems such as Fabry-Perot interferometry for filtering of wavelengths, tunable cavity lasers, micro-holography modules, and wavelength splitters for optical communication systems.

  7. Tractor beam in micro-scale

    NASA Astrophysics Data System (ADS)

    Brzobohatý, O.; Karásek, V.; Šiler, M.; Chvátal, L.; Čižmár, T.; Zemánek, P.

    2014-12-01

    Following the Keplerian idea of radiative forces one would intuitively expect that an object illuminated by sunlight radiation or a laser beam is accelerated along the direction of the photon flow. Such radiation pressure forms the basis for the concept of solar sail, or laser acceleration of micro-particles. In contrast, a hypothetical optical field known from the realm of science-fiction as the "tractor" beam attracts the matter from large distances against the beam propagation. We present a geometry of such"tractor" beam in micro-scale and experimentally demonstrate how it acts upon spherical micro-particles of various sizes or optically self-arranged structures of micro-particles.

  8. Method for producing micro heat panels

    NASA Technical Reports Server (NTRS)

    Camarda, Charles J. (Inventor); Peterson, George P. (Inventor); Rummler, Donald R. (Inventor)

    1997-01-01

    Flat or curved micro heat pipe panels are fabricated by arranging essentially parallel filaments in the shape of the desired panel. The configuration of the filaments corresponds to the desired configuration of the tubes that will constitute the heat pipes. A thermally conductive material is then deposited on and around the filaments to fill in the desired shape of the panel. The filaments are then removed, leaving tubular passageways of the desired configuration and surface texture in the material. The tubes are then filled with a working fluid and sealed. Composite micro heat pipe laminates are formed by layering individual micro heat pipe panels and bonding them to each other to form a single structure. The layering sequence of the micro heat pipe panels can be tailored to transport heat preferentially in specific directions as desired for a particular application.

  9. Micro-ecological behavior and intergroup contact.

    PubMed

    McKeown, Shelley; Cairns, Ed; Stringer, Maurice; Rae, Gordon

    2012-01-01

    Research evaluating intergroup contact has tended to rely on self-report measures. Drawing on recent micro-ecological research, the two studies reported here used a multi-method approach to examine contact in a more holistic fashion. This involved the measurement of observable behavior at the micro-level, intergroup attitudes via infrahumanization and focus groups. Participants were taking part in a community intervention program in Northern Ireland. We conclude that micro-ecological behavior is not necessarily indicative of outgroup attitudes. Although behavior and attitudes changed in line with one another in Study 1 (less aggregation and significantly less infrahumanization), there were no infrahumanization differences between those who sat beside an outgroup member and those who did not. Importantly, the work presented here illustrates a unique method that allows micro-ecological behavioral observations to be made for the first time in non-racial settings. PMID:22558828

  10. Passive ring resonator micro-optical gyroscopes

    NASA Astrophysics Data System (ADS)

    Venediktov, V. Yu; Filatov, Yu V.; Shalymov, E. V.

    2016-05-01

    This paper reviews recent advances in passive micro-optical gyroscopes. In the last decade, most research effort in the area of micro-optical gyros has been concentrated on a configuration that takes advantage of a single-mode passive ring resonator, which is usually fabricated using integrated optical technologies. The dimensions of such micro-optical gyros are comparable to those of micromechanical gyroscopes (area of 10 to 100 mm2) and their sensitivity is considerably better than the sensitivity of the latter, approaching that of fibre-optic and laser gyros. Moreover, microoptical gyros can be made as a single integrated circuit, like the micromechanical gyros, but they have no movable parts, in contrast to their micromechanical counterparts. We also describe the development and investigation of micro-optical gyros produced in our studies.

  11. Evaluation of the micro-carburetor

    SciTech Connect

    Weiss, M.F.; Hall, R.A.; Mazor, S.D.

    1981-08-01

    A prototype sonic, variable-venturi automotive carburetor, developed by Micro Carburetor Corporation, was evaluated for its effects on vehicle performance, fuel economy, and exhaust emissions. A 350 CID Chevrolet Impala vehicle was tested on a chassis dynamometer over the 1975 Federal Test Procedure, urban driving cycle. The Micro-carburetor was tested and compared with stock and modified-stock engine configurations. Subsequently, the test vehicle's performance characteristics were examined with the stock carburetor and again with the Micro-carburetor in a series of on-road driveability tests. The test engine was then removed from the vehicle and installed on an engine dynamometer. Engine tests were conducted to compare the fuel economy, thermal efficiency, and cylinder-to-cylinder mixture distribution of the Micro-carburetor to that of the stock configuration. Test results show increases in thermal efficiency and improvements in fuel economy at all test conditions.

  12. Micro- and nanodevices integrated with biomolecular probes

    PubMed Central

    Alapan, Yunus; Icoz, Kutay; Gurkan, Umut A.

    2016-01-01

    Understanding how biomolecules, proteins and cells interact with their surroundings and other biological entities has become the fundamental design criterion for most biomedical micro- and nanodevices. Advances in biology, medicine, and nanofabrication technologies complement each other and allow us to engineer new tools based on biomolecules utilized as probes. Engineered micro/nanosystems and biomolecules in nature have remarkably robust compatibility in terms of function, size, and physical properties. This article presents the state of the art in micro- and nanoscale devices designed and fabricated with biomolecular probes as their vital constituents. General design and fabrication concepts are presented and three major platform technologies are highlighted: microcantilevers, micro/nanopillars, and microfluidics. Overview of each technology, typical fabrication details, and application areas are presented by emphasizing significant achievements, current challenges, and future opportunities. PMID:26363089

  13. Principles of microRNA Regulation Revealed Through Modeling microRNA Expression Quantitative Trait Loci.

    PubMed

    Budach, Stefan; Heinig, Matthias; Marsico, Annalisa

    2016-08-01

    Extensive work has been dedicated to study mechanisms of microRNA-mediated gene regulation. However, the transcriptional regulation of microRNAs themselves is far less well understood, due to difficulties determining the transcription start sites of transient primary transcripts. This challenge can be addressed using expression quantitative trait loci (eQTLs) whose regulatory effects represent a natural source of perturbation of cis-regulatory elements. Here we used previously published cis-microRNA-eQTL data for the human GM12878 cell line, promoter predictions, and other functional annotations to determine the relationship between functional elements and microRNA regulation. We built a logistic regression model that classifies microRNA/SNP pairs into eQTLs or non-eQTLs with 85% accuracy; shows microRNA-eQTL enrichment for microRNA precursors, promoters, enhancers, and transcription factor binding sites; and depletion for repressed chromatin. Interestingly, although there is a large overlap between microRNA eQTLs and messenger RNA eQTLs of host genes, 74% of these shared eQTLs affect microRNA and host expression independently. Considering microRNA-only eQTLs we find a significant enrichment for intronic promoters, validating the existence of alternative promoters for intragenic microRNAs. Finally, in line with the GM12878 cell line derived from B cells, we find genome-wide association (GWA) variants associated to blood-related traits more likely to be microRNA eQTLs than random GWA and non-GWA variants, aiding the interpretation of GWA results. PMID:27260304

  14. A CAMAC and FASTBUS engineering test environment supported by a MicroVAX/MicroVMS system

    SciTech Connect

    Logg, C.A.

    1987-10-01

    A flexible, multiuser engineering test environment has been established for the engineers in SLAC's Electronic Instrumentation Engineering group. The system hardware includes a standard MicroVAX II and MicroVAX I with multiple CAMAC, FASTBUS, and GPIB instrumentation buses. The system software components include MicroVMS licenses with DECNET/SLACNET, FORTRAN, PASCAL, FORTH, and a versatile graphical display package. In addition, there are several software utilities available to facilitate FASTBUS and CAMAC prototype hardware debugging. 16 refs., 7 figs.

  15. Principles of microRNA Regulation Revealed Through Modeling microRNA Expression Quantitative Trait Loci.

    PubMed

    Budach, Stefan; Heinig, Matthias; Marsico, Annalisa

    2016-08-01

    Extensive work has been dedicated to study mechanisms of microRNA-mediated gene regulation. However, the transcriptional regulation of microRNAs themselves is far less well understood, due to difficulties determining the transcription start sites of transient primary transcripts. This challenge can be addressed using expression quantitative trait loci (eQTLs) whose regulatory effects represent a natural source of perturbation of cis-regulatory elements. Here we used previously published cis-microRNA-eQTL data for the human GM12878 cell line, promoter predictions, and other functional annotations to determine the relationship between functional elements and microRNA regulation. We built a logistic regression model that classifies microRNA/SNP pairs into eQTLs or non-eQTLs with 85% accuracy; shows microRNA-eQTL enrichment for microRNA precursors, promoters, enhancers, and transcription factor binding sites; and depletion for repressed chromatin. Interestingly, although there is a large overlap between microRNA eQTLs and messenger RNA eQTLs of host genes, 74% of these shared eQTLs affect microRNA and host expression independently. Considering microRNA-only eQTLs we find a significant enrichment for intronic promoters, validating the existence of alternative promoters for intragenic microRNAs. Finally, in line with the GM12878 cell line derived from B cells, we find genome-wide association (GWA) variants associated to blood-related traits more likely to be microRNA eQTLs than random GWA and non-GWA variants, aiding the interpretation of GWA results.

  16. Principles of microRNA Regulation Revealed Through Modeling microRNA Expression Quantitative Trait Loci

    PubMed Central

    Budach, Stefan; Heinig, Matthias; Marsico, Annalisa

    2016-01-01

    Extensive work has been dedicated to study mechanisms of microRNA-mediated gene regulation. However, the transcriptional regulation of microRNAs themselves is far less well understood, due to difficulties determining the transcription start sites of transient primary transcripts. This challenge can be addressed using expression quantitative trait loci (eQTLs) whose regulatory effects represent a natural source of perturbation of cis-regulatory elements. Here we used previously published cis-microRNA-eQTL data for the human GM12878 cell line, promoter predictions, and other functional annotations to determine the relationship between functional elements and microRNA regulation. We built a logistic regression model that classifies microRNA/SNP pairs into eQTLs or non-eQTLs with 85% accuracy; shows microRNA-eQTL enrichment for microRNA precursors, promoters, enhancers, and transcription factor binding sites; and depletion for repressed chromatin. Interestingly, although there is a large overlap between microRNA eQTLs and messenger RNA eQTLs of host genes, 74% of these shared eQTLs affect microRNA and host expression independently. Considering microRNA-only eQTLs we find a significant enrichment for intronic promoters, validating the existence of alternative promoters for intragenic microRNAs. Finally, in line with the GM12878 cell line derived from B cells, we find genome-wide association (GWA) variants associated to blood-related traits more likely to be microRNA eQTLs than random GWA and non-GWA variants, aiding the interpretation of GWA results. PMID:27260304

  17. Atrial fibrillation and microRNAs

    PubMed Central

    Santulli, Gaetano; Iaccarino, Guido; De Luca, Nicola; Trimarco, Bruno; Condorelli, Gianluigi

    2014-01-01

    Atrial fibrillation (AF) is the most common sustained arrhythmia, especially in the elderly, and has a significant genetic component. Recently, several independent investigators have demonstrated a functional role for small non-coding RNAs (microRNAs) in the pathophysiology of this cardiac arrhythmia. This report represents a systematic and updated appraisal of the main studies that established a mechanistic association between specific microRNAs and AF, focusing both on the regulation of electrical and structural remodeling of cardiac tissue. PMID:24478726

  18. Bracing micro/macro manipulators control

    SciTech Connect

    Lew, J.Y.; Book, W.J.

    1994-05-01

    This paper proposes a bracing strategy for micro/macro manipulators. The bracing micro/macro manipulator can provide advantages in accurate positioning, large work-space, and contact-task capability however, in exchange for improvement in performance one must accept the complex control problem along wit the complex dynamics. This research develops a control scheme for a bracing manipulator which makes multiple contacts with the environment. Experimental results show the feasibility of the proposed ideas for real world applications.

  19. MicroBooNE Detector Move

    SciTech Connect

    Flemming, Bonnie; Rameika, Gina

    2014-06-25

    On Monday, June 23, 2014 the MicroBooNE detector -- a 30-ton vessel that will be used to study ghostly particles called neutrinos -- was transported three miles across the Fermilab site and gently lowered into the laboratory's Liquid-Argon Test Facility. This video documents that move, some taken with time-lapse camerad, and shows the process of getting the MicroBooNE detector to its new home.

  20. MicroBooNE Detector Move

    ScienceCinema

    Flemming, Bonnie; Rameika, Gina

    2016-07-12

    On Monday, June 23, 2014 the MicroBooNE detector -- a 30-ton vessel that will be used to study ghostly particles called neutrinos -- was transported three miles across the Fermilab site and gently lowered into the laboratory's Liquid-Argon Test Facility. This video documents that move, some taken with time-lapse camerad, and shows the process of getting the MicroBooNE detector to its new home.

  1. Precise 3D printing of micro/nanostructures using highly conductive carbon nanotube-thiol-acrylate composites

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Xiong, W.; Jiang, L. J.; Zhou, Y. S.; Lu, Y. F.

    2016-04-01

    Two-photon polymerization (TPP) is of increasing interest due to its unique combination of truly three-dimensional (3D) fabrication capability and ultrahigh spatial resolution of ~40 nm. However, the stringent requirements of non-linear resins seriously limit the material functionality of 3D printing via TPP. Precise fabrication of 3D micro/nanostructures with multi-functionalities such as high electrical conductivity and mechanical strength is still a long-standing challenge. In this work, TPP fabrication of arbitrary 3D micro/nanostructures using multi-walled carbon nanotube (MWNT)-thiolacrylate (MTA) composite resins has been developed. Up to 0.2 wt% MWNTs have been incorporated into thiol-acrylate resins to form highly stable and uniform composite photoresists without obvious degradation for one week at room temperature. Various functional 3D micro/nanostructures including woodpiles, micro-coils, spiral-like photonic crystals, suspended micro-bridges, micro-gears and complex micro-cars have been successfully fabricated. The MTA composite resin offers significant enhancements in electrical conductivity and mechanical strength, and on the same time, preserving high optical transmittance and flexibility. Tightly controlled alignment of MWNTs and the strong anisotropy effect were confirmed. Microelectronic devices including capacitors and resistors made of the MTA composite polymer were demonstrated. The 3D micro/nanofabrication using the MTA composite resins enables the precise 3D printing of micro/nanostructures of high electrical conductivity and mechanical strength, which is expected to lead a wide range of device applications, including micro/nano-electromechanical systems (MEMS/NEMS), integrated photonics and 3D electronics.

  2. Modulation of microRNA Activity by Semi-microRNAs

    PubMed Central

    Plante, Isabelle; Plé, Hélène; Landry, Patricia; Gunaratne, Preethi H.; Provost, Patrick

    2012-01-01

    The ribonuclease Dicer plays a central role in the microRNA pathway by catalyzing the formation of 19–24-nucleotide (nt) long microRNAs. Subsequently incorporated into Argonaute 2 (Ago2) effector complexes, microRNAs are known to regulate messenger RNA (mRNA) translation. Whether shorter RNA species derived from microRNAs exist and play a role in mRNA regulation remains unknown. Here, we report the serendipitous discovery of a 12-nt long RNA species corresponding to the 5′ region of the microRNA let-7, and tentatively termed semi-microRNA, or smiRNA. Using a smiRNA derived from the precursor of miR-223 as a model, we show that 12-nt long smiRNA species are devoid of any direct mRNA regulatory activity, as assessed in a reporter gene activity assay in transfected cultured human cells. However, smiR-223 was found to modulate the ability of the microRNA from which it derives to mediate translational repression or cleavage of reporter mRNAs. Our findings suggest that the 12-nt RNA species, generated along the microRNA pathway, may participate to the control of gene expression by regulating the activity of the related full-length mature microRNA in vivo. PMID:22675332

  3. Fabrication of Micro Gears by Micro-Powder Injection-Compression Molding

    NASA Astrophysics Data System (ADS)

    Jang, Jin Man; Lee, Wonsik; Son, Seong-Ho; Ko, Se-Hyun; Kim, Il-Ho

    Micro-spur gears were fabricated by powder injection-compression molding and micro-two-step gears were produced through stacking and sintering of the green parts. Shrinkage of micro-gears by sintering was larger in teeth and with increase of compression pressure, shrinkage was decreased due to increase of density in green parts. Surface roughness of sintered body was reduced to a few hundreds of nanometers by ultrasonic micro-polishing. The joining of green bodies by stacking and sintering was achieved using the pressurized sintering and insert of feedstock powders between both green bodies.

  4. Diamond single micro-crystals and graphitic micro-balls’ formation in plasmoids under atmospheric pressure

    NASA Astrophysics Data System (ADS)

    Pothiraja, Ramasamy; Kartaschew, Konstantin; Bibinov, Nikita; Havenith, Martina; Awakowicz, Peter

    2015-03-01

    Plasmoids are produced in the argon filamentary discharge. By going through hydrocarbon gas, the plasmoids collect carbon material. These plasmoids produce diamond single micro-crystals upon contact on the inner surface of cavity in air atmosphere. When the plasmoid’s contact point on the substrate is in inert atmosphere, they deposit their material as micro-balls with a graphite core. The dimension and nature of the micro-materials deposited by the plasmoids are analysed using scanning electron microscopy and Raman microspectroscopy. The compressive residual stress in the deposited micro-diamonds varies in the range -7 to -21 GPa.

  5. Surface micromachined electrostatically actuated micro peristaltic pump.

    PubMed

    Xie, Jun; Shih, Jason; Lin, Qiao; Yang, Bozhi; Tai, Yu-Chong

    2004-10-01

    An electrostatically actuated micro peristaltic pump is reported. The micro pump is entirely surface micromachined using a multilayer parylene technology. Taking advantage of the multilayer technology, the micro pump design enables the pumped fluid to be isolated from the electric field. Electrostatic actuation of the parylene membrane using both DC and AC voltages was demonstrated and applied to fluid pumping based on a 3-phase peristaltic sequence. A maximum flow rate of 1.7 nL min(-1) and an estimated pumping pressure of 1.6 kPa were achieved at 20 Hz phase frequency. A dynamic analysis was also performed with a lumped-parameter model for the peristaltic pump. The analysis results allow a quantitative understanding of the peristaltic pumping operation, and correctly predict the trends exhibited by the experimental data. The small footprint of the micro pump is well suited for large-scale integration of microfluidics. Moreover, because the same platform technology has also been used to fabricate other devices (e.g. valves, electrospray ionization nozzles, filters and flow sensors), the integration of these different devices can potentially lead to versatile and functional micro total analysis systems (microTAS).

  6. Laser 3D micro-manufacturing

    NASA Astrophysics Data System (ADS)

    Piqué, Alberto; Auyeung, Raymond C. Y.; Kim, Heungsoo; Charipar, Nicholas A.; Mathews, Scott A.

    2016-06-01

    Laser-based materials processing techniques are gaining widespread use in micro-manufacturing applications. The use of laser microfabrication techniques enables the processing of micro- and nanostructures from a wide range of materials and geometries without the need for masking and etching steps commonly associated with photolithography. This review aims to describe the broad applications space covered by laser-based micro- and nanoprocessing techniques and the benefits offered by the use of lasers in micro-manufacturing processes. Given their non-lithographic nature, these processes are also referred to as laser direct-write and constitute some of the earliest demonstrations of 3D printing or additive manufacturing at the microscale. As this review will show, the use of lasers enables precise control of the various types of processing steps—from subtractive to additive—over a wide range of scales with an extensive materials palette. Overall, laser-based direct-write techniques offer multiple modes of operation including the removal (via ablative processes) and addition (via photopolymerization or printing) of most classes of materials using the same equipment in many cases. The versatility provided by these multi-function, multi-material and multi-scale laser micro-manufacturing processes cannot be matched by photolithography nor with other direct-write microfabrication techniques and offer unique opportunities for current and future 3D micro-manufacturing applications.

  7. Homogenization in micro-magneto-mechanics

    NASA Astrophysics Data System (ADS)

    Sridhar, A.; Keip, M.-A.; Miehe, C.

    2016-07-01

    Ferromagnetic materials are characterized by a heterogeneous micro-structure that can be altered by external magnetic and mechanical stimuli. The understanding and the description of the micro-structure evolution is of particular importance for the design and the analysis of smart materials with magneto-mechanical coupling. The macroscopic response of the material results from complex magneto-mechanical interactions occurring on smaller length scales, which are driven by magnetization reorientation and associated magnetic domain wall motions. The aim of this work is to directly base the description of the macroscopic magneto-mechanical material behavior on the micro-magnetic domain evolution. This will be realized by the incorporation of a ferromagnetic phase-field formulation into a macroscopic Boltzmann continuum by the use of computational homogenization. The transition conditions between the two scales are obtained via rigorous exploitation of rate-type and incremental variational principles, which incorporate an extended version of the classical Hill-Mandel macro-homogeneity condition covering the phase field on the micro-scale. An efficient two-scale computational scenario is developed based on an operator splitting scheme that includes a predictor for the magnetization on the micro-scale. Two- and three-dimensional numerical simulations demonstrate the performance of the method. They investigate micro-magnetic domain evolution driven by macroscopic fields as well as the associated overall hysteretic response of ferromagnetic solids.

  8. Replicated micro-optics for multimedia products

    NASA Astrophysics Data System (ADS)

    Salt, Martin; Rossi, Markus

    2006-04-01

    Advances in design, materials and production technology for micro-optical components have led to strong growth in their use in today's consumer products. In particular, micro-optical components produced by replication technologies such as UV embossing can now withstand the severe processing and environmental requirements of the consumer electronics industry, including lead-free IR reflow and thermal shock. With their small size and low weight, as well as the possibility of optical function not achievable by conventional optics, micro-optical components and systems are finding applications in a wide variety of products. In the field of multimedia, novel designs and new production techniques are enabling applications in key areas such as illumination and display. The extreme compactness of micro-optical components, with typical thickness under 1 mm and footprints of only some millimeters square, makes them a natural candidate for consumer products such as mobile phones, pocket projectors and displays. Advances in UV embossing technology, enabling micro-optics to be mounted over various light sources in a variety of different ways, also allow extremely compact opto-electronic modules to be realized at highly competitive prices. In this paper we summarize recent technology developments and describe a number of multimedia applications utilizing state-of-the-art micro-optics.

  9. Columbus Verification Control Approach Versus Micro-gravity Requirement.

    NASA Astrophysics Data System (ADS)

    Marucchi-Chierro, P.; Martini, M.

    2004-08-01

    The European project manned module Columbus, as part of the International Space Station has been conceived to allow scientific experiments on micro- gravity environment. In order to face against this challenging Design goal, Alenia Spazio developed a dedicated control approach, based on budget allocation of the mechanical power, covering the design, the Analysis and the Verification aspects from system level down to the equipment one. This Control method covers both the evaluations by analysis and/or by testing of the Columbus Structural and Vibro-acoustic transmission paths and the characterization of the disturbers (as Environment Control Life System fans, Thermal Control System pumps and valves, etc.) in terms of force at the equipment interfaces and Sound power Level emitted by the disturbers in the surrounding volume. A dedicated methodology on how to derive the induced disturber's interface forcing functions has been developed in the frame of this project.This paper reports the most significant outcomes during the whole verification and test process at equipment and system level for the derivation of the disturber forcing function. The originality of the method is based on the fact that in the frame of the Columbus Design/Verification cycle, testing has been done at equipment and at system level for the : a) derivation of the equipment Forcing Function when installed on a reference base-plate b) derivation of the disturbers Forcing function when installed o Columbus in the frame of the complete Micro-gravity System Test that allowed both the characterization of : - the structural and the vibro-acoustic system transmissibility by the use of artificial exciters (as shakers and sound source) - the micro-gravity Environment by the Columbus disturbers activation c) Definition of a combination method of forcing function in order to get similar results coming function in order to get similar results coming from both the equipment characterization standing- alone and

  10. Advanced Micro Turbine System (AMTS) -C200 Micro Turbine -Ultra-Low Emissions Micro Turbine

    SciTech Connect

    Capstone Turbine Corporation

    2007-12-31

    In September 2000 Capstone Turbine Corporation commenced work on a US Department of Energy contract to develop and improve advanced microturbines for power generation with high electrical efficiency and reduced pollutants. The Advanced MicroTurbine System (AMTS) program focused on: (1) The development and implementation of technology for a 200 kWe scale high efficiency microturbine system (2) The development and implementation of a 65 kWe microturbine which meets California Air Resources Board (CARB) emissions standards effective in 2007. Both of these objectives were achieved in the course of the AMTS program. At its conclusion prototype C200 Microturbines had been designed, assembled and successfully completed field demonstration. C65 Microturbines operating on natural, digester and landfill gas were also developed and successfully tested to demonstrate compliance with CARB 2007 Fossil Fuel Emissions Standards for NOx, CO and VOC emissions. The C65 Microturbine subsequently received approval from CARB under Executive Order DG-018 and was approved for sale in California. The United Technologies Research Center worked in parallel to successfully execute a RD&D program to demonstrate the viability of a low emissions AMS which integrated a high-performing microturbine with Organic Rankine Cycle systems. These results are documented in AMS Final Report DOE/CH/11060-1 dated March 26, 2007.

  11. Micro-Doppler classification of riders and riderless horses

    NASA Astrophysics Data System (ADS)

    Tahmoush, David

    2014-05-01

    Micro-range Micro-Doppler can be used to isolate particular parts of the radar signature, and in this case we demonstrate the differences in the signature between a walking horse versus a walking horse with a rider. Using micro-range micro-Doppler, we can distinguish the radar returns from the rider as separate from the radar returns of the horse.

  12. 37 CFR 1.29 - Micro entity status.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2014-07-01 2014-07-01 false Micro entity status. 1.29... Micro entity status. (a) To establish micro entity status under this paragraph, the applicant must... establish micro entity status under this paragraph, the applicant must certify that: (1) The...

  13. 37 CFR 1.29 - Micro entity status.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2013-07-01 2013-07-01 false Micro entity status. 1.29... Micro entity status. (a) To establish micro entity status under this paragraph, the applicant must... establish micro entity status under this paragraph, the applicant must certify that: (1) The...

  14. Magnetically levitated micro-robotics

    NASA Astrophysics Data System (ADS)

    Pelrine, Ronald Edward

    The use of magnetic levitation (maglev) as a microrobot drive is examined theoretically and experimentally. Microrobots are small, programmable, multi-degree of freedom mechanical devices. Maglev drive appears capable of addressing a number of important microrobotics issues, including friction, wear, material transport, and ability to tolerate adverse environments. These issues, often involving problems beyond the technical feasibility of single microrobots, must be dealt with effectively in order to realize the goal of low cost, integrated, multi-manipulator systems operating on small scales. Maglev microrobot drive is compared with other possible microrobot drives, particularly electrostatic drive. Various magnetic levitation systems are examined next, showing the rich variety of possible maglev microrobots. Out of 48 physically distinct maglev drive systems, the focus is narrowed using the requirements of an integrated micro-factory (IMF). These requirements suggest that at the present level of technical development the maglev system of primary interest is one which uses air core electromagnets driving a permanent magnet manipulator. Various air core electromagnets are discussed, including planar electromagnets suitable for a high level of silicon integration. Several force/torque environments are considered, such as solid and liquid surfaces. These different environments primarily affect the control strategy's performance and requirements, such as the ability to operate in open loop modes. The analysis was used to build a number of experimental prototypes, including a planar type, 1-D manipulator transport path, and 4. degree of freedom microrobots capable of 0.5 micron resolutions. Finally, future trends in the field such as superconductive systems are discussed.

  15. MicroRNAs and cancer.

    PubMed

    Cowland, Jack B; Hother, Christoffer; Grønbaek, Kirsten

    2007-10-01

    MicroRNAs (miRNAs) are a recently discovered group of small RNA molecules involved in the regulation of gene expression. Analogously to mRNAs, the non-protein-encoding pri-miRNAs are synthesized by RNA polymerase II and post-transcriptionally modified by addition of a 5'-cap and a 3'-poly (A) tail. Subsequently, the pri-miRNA undergoes a number of processing steps in the nucleus and cytoplasm, and ends up as a mature approximately 22 nt miRNA, which can exert its function by binding to the 3'-untranslated region of a subset of mRNAs. Binding of the miRNA to the mRNA results in a reduced translation rate and/or increased degradation of the mRNA. In this way a large number of cellular pathways, such as cellular proliferation, differentiation, and apoptosis, are regulated by mi-RNAs. As corruption of these pathways is the hallmark of many cancers, dysregulation of miRNA biogenesis or expression levels may lead to tumorigenesis. The mechanisms that alter the expression of miRNAs are similar to those that change the expression levels of mRNAs of tumor suppressor- and oncogenes, i.e. gross genomic aberrations, epigenetic changes, and minor mutations affecting the expression level, processing, or target-interaction potential of the miRNA. Furthermore, expression profiling of miRNAs has been found to be useful for classification of different tumor types. Taken together, miRNAs can be classified as onco-miRs or tumor suppressor-miRs, and may turn out to be potential targets for cancer therapy.

  16. Micro-hollow cathode dischargers

    SciTech Connect

    Schoenbach, K.H.; Verhappen, R.; Peterkin, F.E.

    1995-12-31

    In order to develop a hollow cathode discharge (HCD) with its increased current over planar electrode glow discharges, the cathode fall, which is on the order of the mean free path for ionization, must be comparable in length to the hole diameter. This indicates that the discharge parameters vary with pressure, p, times hole diameter, D. The pD product for stable operation of a hollow cathosde discharge was quoted to be on the order of one to ten Torr cm for noble gases, less for molecular gases. White (1959) observed the hollow cathode effect in a neon discharge at a pressure of 100 Torr when the hole dimensions were less than 1 mm. The cathode hole in his experiments changed from a cylindrical into a spherical cavity due to sputtering. The anode consisted in White`s experiment of a pin on the axis of the discharge geometry. We have studied micro-hollow (submillimeter) cathode discharges between two electrodes with aligned cylindrical holes by determining the current-voltage characteristics and the visual appearance of the discharge in argon over a wide range of pressure and voltage. The cross-section of the discharge geometry. The cathode is made of molybdenum or barium oxide inserted into a tungsten matrix (dispenser-cathode), the anode of molybdenum, and the dielectric spacer is mica. The discharge was operated under dc conditions, with half-wave rectified ac voltage applied, and pulsed with a 400 {mu}s rectangular voltage pulse. The lower limit in pressure was determined by the maximum voltage which could be applied to the discharge geometry without breakdown along insulators. The upper limit, in this study, is determined by the transition from cathode electrode emission due to ion-impact to thermal emission of electrons, which causes a dramatic increase in current and a drop in forward voltage to values on the order of 20 V.

  17. Rapid generation of microRNA sponges for microRNA inhibition.

    PubMed

    Kluiver, Joost; Gibcus, Johan H; Hettinga, Chris; Adema, Annelies; Richter, Mareike K S; Halsema, Nancy; Slezak-Prochazka, Izabella; Ding, Ye; Kroesen, Bart-Jan; van den Berg, Anke

    2012-01-01

    MicroRNA (miRNA) sponges are transcripts with repeated miRNA antisense sequences that can sequester miRNAs from endogenous targets. MiRNA sponges are valuable tools for miRNA loss-of-function studies both in vitro and in vivo. We developed a fast and flexible method to generate miRNA sponges and tested their efficiency in various assays. Using a single directional ligation reaction we generated sponges with 10 or more miRNA binding sites. Luciferase and AGO2-immuno precipitation (IP) assays confirmed effective binding of the miRNAs to the sponges. Using a GFP competition assay we showed that miR-19 sponges with central mismatches in the miRNA binding sites are efficient miRNA inhibitors while sponges with perfect antisense binding sites are not. Quantification of miRNA sponge levels suggests that this is at least in part due to degradation of the perfect antisense sponge transcripts. Finally, we provide evidence that combined inhibition of miRNAs of the miR-17∼92 cluster results in a more effective growth inhibition as compared to inhibition of individual miRNAs. In conclusion, we describe and validate a method to rapidly generate miRNA sponges for miRNA loss-of-function studies. PMID:22238599

  18. Effective Medium Theory for Drag Reducing Micro-patterned Surfaces in Turbulent Flows

    NASA Astrophysics Data System (ADS)

    Battiato, I.

    2013-12-01

    Inspired by the lotus effect, many studies in the last decade have focused on micro- and nano-patterned surfaces. They revealed that patterns at the micro-scale combined with high contact angles can significantly reduce skin drag. However, the mechanisms and parameters that control drag reduction, e.g. Reynolds number and pattern geometry, are still unclear. We propose an effective medium representation of the micro-features, that treats the latter as a porous medium, and provides a framework to model flow over patterned surfaces in both Cassie and Wenzel states. Our key result is a closed-form expression for the skin friction coefficient in terms of frictional Reynolds (or Karman) number in turbulent regime, the viscosity ratio between the fluid in and above the features, and their geometrical properties. We apply the proposed model to turbulent flows over superhydrophobic ridged surfaces. The model predictions agree with laboratory experiments for Reynolds numbers ranging from 3000 to 10000.

  19. Effective Medium Theory for Drag Reducing Micro-patterned Surfaces in Turbulent Flows

    NASA Astrophysics Data System (ADS)

    Battiato, Ilenia

    2013-11-01

    Inspired by the lotus effect, many studies in the last decade have focused on micro- and nano-patterned surfaces. They revealed that patterns at the micro-scale combined with high contact angles can significantly reduce skin drag. However, the mechanisms and parameters that control drag reduction, e.g. Reynolds number and pattern geometry, are still unclear. We propose an effective medium representation of the micro-features that treats the latter as a porous medium, and provides a framework to model flows over patterned surfaces in both Cassie and Wenzel states. Our key result is a closed-form expression for the skin friction coefficient in terms of frictional Reynolds (or Karman) number in turbulent regime. We apply the proposed model to turbulent flow over superhydrophobic ridged surfaces. The model predictions agree with laboratory experiments for Reynolds numbers ranging from 3000 to 10000.

  20. Recent Progress on Bioinspired Self-Propelled Micro/Nanomotors via Controlled Molecular Self-Assembly.

    PubMed

    Wu, Zhiguang; Lin, Xiankun; Si, Tieyan; He, Qiang

    2016-06-01

    The combination of bottom-up controllable self-assembly technique with bioinspired design has opened new horizons in the development of self-propelled synthetic micro/nanomotors. Over the past five years, a significant advances toward the construction of bioinspired self-propelled micro/nanomotors has been witnessed based on the controlled self-assembly technique. Such a strategy permits the realization of autonomously synthetic motors with engineering features, such as sizes, shapes, composition, propulsion mechanism, and function. The construction, propulsion mechanism, and movement control of synthetic micro/nanomotors in connection with controlled self-assembly in recent research activities are summarized. These assembled nanomotors are expected to have a tremendous impact on current artificial nanomachines in future and hold potential promise for biomedical applications including drug targeted delivery, photothermal cancer therapy, biodetoxification, treatment of atherosclerosis, artificial insemination, crushing kidney stones, cleaning wounds, and removing blood clots and parasites.

  1. Recent Progress on Bioinspired Self-Propelled Micro/Nanomotors via Controlled Molecular Self-Assembly.

    PubMed

    Wu, Zhiguang; Lin, Xiankun; Si, Tieyan; He, Qiang

    2016-06-01

    The combination of bottom-up controllable self-assembly technique with bioinspired design has opened new horizons in the development of self-propelled synthetic micro/nanomotors. Over the past five years, a significant advances toward the construction of bioinspired self-propelled micro/nanomotors has been witnessed based on the controlled self-assembly technique. Such a strategy permits the realization of autonomously synthetic motors with engineering features, such as sizes, shapes, composition, propulsion mechanism, and function. The construction, propulsion mechanism, and movement control of synthetic micro/nanomotors in connection with controlled self-assembly in recent research activities are summarized. These assembled nanomotors are expected to have a tremendous impact on current artificial nanomachines in future and hold potential promise for biomedical applications including drug targeted delivery, photothermal cancer therapy, biodetoxification, treatment of atherosclerosis, artificial insemination, crushing kidney stones, cleaning wounds, and removing blood clots and parasites. PMID:27073065

  2. Buried centimeter-long micro- and nanochannel arrays in porous silicon and glass.

    PubMed

    Azimi, Sara; Dang, Zhiya; Zhang, Ce; Song, Jiao; Breese, Mark B H; Sow, Chorng Haur; van Kan, Jeroen A; van der Maarel, Johan R C

    2014-06-21

    We developed a simple process to fabricate deeply buried micro- and nanoscale channels in glass and porous silicon from bulk silicon using a combination of ion beam irradiation, electrochemical anodization and high temperature oxidation. The depth, width and length of these structures can be controllably varied and we successfully fabricated an array of centimeter-long buried micro- and nanochannels. This process allows densely packed, arbitrary-shaped channel geometries with micro- to nanoscale dimensions to be produced in a three-dimensional multilevel architecture, providing a route to fabricate complex devices for use in nanofluidics and lab-on-a-chip systems. We demonstrate the integration of these channels with large reservoirs for DNA linearization in high aspect ratio nanochannels.

  3. Capillary optics for micro x-ray fluorescence analysis

    SciTech Connect

    Bjeoumikhov, A.; Langhoff, N.; Bjeoumikhova, S.; Wedell, R.

    2005-06-15

    Practically achieved parameters of capillary optics are presented. A micro x-ray fluorescence (XRF) arrangement was realized by using a microfocus x-ray tube and a capillary optic. Several examples for application of micro XRF are given. It was shown that polycapillary lenses free of the 'halo effect' well suited for micro XRF of heavy elements can be manufactured. Limits of opportunities for micro XRF applications and further development for micro XRF by using capillary optics are analyzed.

  4. Laser micro welding of copper and aluminium using filler materials

    NASA Astrophysics Data System (ADS)

    Esser, Gerd; Mys, Ihor; Schmidt, Michael H.

    2004-10-01

    The most evident trend in electronics production is towards miniaturization. Regarding the materials involved, another trend can be observed: intelligent combinations of different materials. One example is the combination of copper and aluminium. Copper is the material of choice for electronic packaging applications due to its superior electrical and thermal conductivity. On the other hand, aluminium offers technical and economical advantages with respect to cost and component weight -- still providing thermal and electrical properties acceptable for numerous applications. Especially for high volume products, the best solution often seems to be a combination of both materials. This fact raises the question of joining copper and aluminium. With respect to miniaturization laser micro welding is a very promising joining technique. Unfortunately, the metallurgical incompatibility of copper and aluminium easily results in the formation of brittle intermetallic phases and segregations during laser welding, thus generating an unacceptable quality of the joints. This paper presents investigations on enhancing the quality during laser micro welding of copper and aluminium for applications in electronics production. In order to eliminate the formation of brittle intermetallic phases, the addition of a filter material in form of a foil has been investigated. It can be shown that the addition of pure metals such as nickel and especially silver significantly reduces the occurrence of brittle phases in the joining area and therefore leads to an increase in welding quality. The proper control of the volume fractions of copper, aluminium and filler material in the melting zone helps to avoid materials segregation and reduces residual stress, consequently leading to a reduction of crack affinity and a stabilization of the mechanical and electrical properties.

  5. Combined environmental stresses

    NASA Technical Reports Server (NTRS)

    Murray, R. H.; Mccally, M.

    1973-01-01

    Tolerance levels, physiological effects, and performance degradation during simultaneous or sequential exposures to two environmental stresses, and also three or more simultaneous stresses are described. Environmental stress combinations are characterized by four descriptors: order of occurrence, duration of exposure, severity of exposure, and type of interaction. Combined stress data and facilities for combined stress study are briefly mentioned.

  6. Identification of a pan-cancer oncogenic microRNA superfamily anchored by a central core seed motif

    NASA Astrophysics Data System (ADS)

    Hamilton, Mark P.; Rajapakshe, Kimal; Hartig, Sean M.; Reva, Boris; McLellan, Michael D.; Kandoth, Cyriac; Ding, Li; Zack, Travis I.; Gunaratne, Preethi H.; Wheeler, David A.; Coarfa, Cristian; McGuire, Sean E.

    2013-11-01

    MicroRNAs modulate tumorigenesis through suppression of specific genes. As many tumour types rely on overlapping oncogenic pathways, a core set of microRNAs may exist, which consistently drives or suppresses tumorigenesis in many cancer types. Here we integrate The Cancer Genome Atlas (TCGA) pan-cancer data set with a microRNA target atlas composed of publicly available Argonaute Crosslinking Immunoprecipitation (AGO-CLIP) data to identify pan-tumour microRNA drivers of cancer. Through this analysis, we show a pan-cancer, coregulated oncogenic microRNA ‘superfamily’ consisting of the miR-17, miR-19, miR-130, miR-93, miR-18, miR-455 and miR-210 seed families, which cotargets critical tumour suppressors via a central GUGC core motif. We subsequently define mutations in microRNA target sites using the AGO-CLIP microRNA target atlas and TCGA exome-sequencing data. These combined analyses identify pan-cancer oncogenic cotargeting of the phosphoinositide 3-kinase, TGFβ and p53 pathways by the miR-17-19-130 superfamily members.

  7. 3D micro-XRF for cultural heritage objects: new analysis strategies for the investigation of the Dead Sea Scrolls.

    PubMed

    Mantouvalou, Ioanna; Wolff, Timo; Hahn, Oliver; Rabin, Ira; Lühl, Lars; Pagels, Marcel; Malzer, Wolfgang; Kanngiesser, Birgit

    2011-08-15

    A combination of 3D micro X-ray fluorescence spectroscopy (3D micro-XRF) and micro-XRF was utilized for the investigation of a small collection of highly heterogeneous, partly degraded Dead Sea Scroll parchment samples from known excavation sites. The quantitative combination of the two techniques proves to be suitable for the identification of reliable marker elements which may be used for classification and provenance studies. With 3D micro-XRF, the three-dimensional nature, i.e. the depth-resolved elemental composition as well as density variations, of the samples was investigated and bromine could be identified as a suitable marker element. It is shown through a comparison of quantitative and semiquantitative values for the bromine content derived using both techniques that, for elements which are homogeneously distributed in the sample matrix, quantification with micro-XRF using a one-layer model is feasible. Thus, the possibility for routine provenance studies using portable micro-XRF instrumentation on a vast amount of samples, even on site, is obtained through this work.

  8. How microRNA and transcription factor co-regulatory networks affect osteosarcoma cell proliferation.

    PubMed

    Poos, Kathrin; Smida, Jan; Nathrath, Michaela; Maugg, Doris; Baumhoer, Daniel; Korsching, Eberhard

    2013-01-01

    Osteosarcomas (OS) are complex bone tumors with various genomic alterations. These alterations affect the expression and function of several genes due to drastic changes in the underlying gene regulatory network. However, we know little about critical gene regulators and their functional consequences on the pathogenesis of OS. Therefore, we aimed to determine microRNA and transcription factor (TF) co-regulatory networks in OS cell proliferation. Cell proliferation is an essential part in the pathogenesis of OS and deeper understanding of its regulation might help to identify potential therapeutic targets. Based on expression data of OS cell lines divided according to their proliferative activity, we obtained 12 proliferation-related microRNAs and corresponding target genes. Therewith, microRNA and TF co-regulatory networks were generated and analyzed regarding their structure and functional influence. We identified key co-regulators comprising the microRNAs miR-9-5p, miR-138, and miR-214 and the TFs SP1 and MYC in the derived networks. These regulators are implicated in NFKB- and RB1-signaling and focal adhesion processes based on their common or interacting target genes (e.g., CDK6, CTNNB1, E2F4, HES1, ITGA6, NFKB1, NOTCH1, and SIN3A). Thus, we proposed a model of OS cell proliferation which is primarily co-regulated through the interactions of the mentioned microRNA and TF combinations. This study illustrates the benefit of systems biological approaches in the analysis of complex diseases. We integrated experimental data with publicly available information to unravel the coordinated (post)-transcriptional control of microRNAs and TFs to identify potential therapeutic targets in OS. The resulting microRNA and TF co-regulatory networks are publicly available for further exploration to generate or evaluate own hypotheses of the pathogenesis of OS (http://www.complex-systems.uni-muenster.de/co_networks.html).

  9. The Genomic Analysis of Erythrocyte microRNA Expression in Sickle Cell Diseases

    PubMed Central

    Chen, Shao-Yin; Wang, Yulei; Telen, Marilyn J.; Chi, Jen-Tsan

    2008-01-01

    Background Since mature erythrocytes are terminally differentiated cells without nuclei and organelles, it is commonly thought that they do not contain nucleic acids. In this study, we have re-examined this issue by analyzing the transcriptome of a purified population of human mature erythrocytes from individuals with normal hemoglobin (HbAA) and homozygous sickle cell disease (HbSS). Methods and Findings Using a combination of microarray analysis, real-time RT-PCR and Northern blots, we found that mature erythrocytes, while lacking ribosomal and large-sized RNAs, contain abundant and diverse microRNAs. MicroRNA expression of erythrocytes was different from that of reticulocytes and leukocytes, and contributed the majority of the microRNA expression in whole blood. When we used microRNA microarrays to analyze erythrocytes from HbAA and HbSS individuals, we noted a dramatic difference in their microRNA expression pattern. We found that miR-320 played an important role for the down-regulation of its target gene, CD71 during reticulocyte terminal differentiation. Further investigation revealed that poor expression of miR-320 in HbSS cells was associated with their defective downregulation CD71 during terminal differentiation. Conclusions In summary, we have discovered significant microRNA expression in human mature erythrocytes, which is dramatically altered in HbSS erythrocytes and their defect in terminal differentiation. Thus, the global analysis of microRNA expression in circulating erythrocytes can provide mechanistic insights into the disease phenotypes of erythrocyte diseases. PMID:18523662

  10. Functional MicroRNA Involved in Endometriosis

    PubMed Central

    Creighton, Chad J.; Han, Derek Y.; Zariff, Azam; Anderson, Matthew L.; Gunaratne, Preethi H.; Matzuk, Martin M.

    2011-01-01

    Endometriosis is a common disease seen by gynecologists. Clinical features involve pelvic pain and unexplained infertility. Although endometriosis is pathologically characterized by endometrial tissue outside the normal uterine location, endometriosis is otherwise not easily explained. Endometriomas, endometriotic cysts of the ovary, typically cause pain and distortion of pelvic anatomy. To begin to understand the pathogenesis of endometriomas, we describe the first transcriptome-microRNAome analysis of endometriomas and eutopic endometrium using next-generation sequencing technology. Using this approach, we generated a total of more than 54 million independent small RNA reads from our 19 clinical samples. At the microRNA level, we found 10 microRNA that were up-regulated (miR-202, 193a-3p, 29c, 708, 509-3-5p, 574-3p, 193a-5p, 485-3p, 100, and 720) and 12 microRNA that were down-regulated (miR-504, 141, 429, 203, 10a, 200b, 873, 200c, 200a, 449b, 375, and 34c-5p) in endometriomas compared with endometrium. Using in silico prediction algorithms, we correlated these microRNA with their corresponding differentially expressed mRNA targets. To validate the functional roles of microRNA, we manipulated levels of miR-29c in an in vitro system of primary cultures of human endometrial stromal fibroblasts. Extracellular matrix genes that were potential targets of miR-29c in silico were significantly down-regulated using this biological in vitro system. In vitro functional studies using luciferase reporter constructs further confirmed that miR-29c directly affects specific extracellular matrix genes that are dysregulated in endometriomas. Thus, miR-29c and other abnormally regulated microRNA appear to play important roles in the pathophysiology of uterine function and dysfunction. PMID:21436257

  11. MicroRT - Small animal conformal irradiator

    SciTech Connect

    Stojadinovic, S.; Low, D. A.; Hope, A. J.; Vicic, M.; Deasy, J. O.; Cui, J.; Khullar, D.; Parikh, P. J.; Malinowski, K. T.; Izaguirre, E. W.; Mutic, S.; Grigsby, P. W.

    2007-12-15

    A novel small animal conformal radiation therapy system has been designed and prototyped: MicroRT. The microRT system integrates multimodality imaging, radiation treatment planning, and conformal radiation therapy that utilizes a clinical {sup 192}Ir isotope high dose rate source as the radiation source (teletherapy). A multiparameter dose calculation algorithm based on Monte Carlo dose distribution simulations is used to efficiently and accurately calculate doses for treatment planning purposes. A series of precisely machined tungsten collimators mounted onto a cylindrical collimator assembly is used to provide the radiation beam portals. The current design allows a source-to-target distance range of 1-8 cm at four beam angles: 0 deg. (beam oriented down), 90 deg., 180 deg., and 270 deg. The animal is anesthetized and placed in an immobilization device with built-in fiducial markers and scanned using a computed tomography, magnetic resonance, or positron emission tomography scanner prior to irradiation. Treatment plans using up to four beam orientations are created utilizing a custom treatment planning system--microRTP. A three-axis computer-controlled stage that supports and accurately positions the animals is programmed to place the animal relative to the radiation beams according to the microRTP plan. The microRT system positioning accuracy was found to be submillimeter. The radiation source is guided through one of four catheter channels and placed in line with the tungsten collimators to deliver the conformal radiation treatment. The microRT hardware specifications, the accuracy of the treatment planning and positioning systems, and some typical procedures for radiobiological experiments that can be performed with the microRT device are presented.

  12. Fumigant combinations for Cyperus esculentum L control.

    PubMed

    Hutchinson, Chad M; McGiffen, Milton E; Sims, James J; Becker, J Ole

    2004-04-01

    The phase-out of methyl bromide as a soil fumigant has stimulated research into the use of other soil fumigants for weed control. Methyl bromide, methyl iodide, propargyl bromide, 1,3-dichloropropene (1,3-D) and metam-sodium were tested alone and in combination with chloropicrin in laboratory experiments to determine their efficacy against Cyperus esculentus L (yellow nutsedge) tubers. Propargyl bromide and metam-sodium were the most efficacious fumigants tested, with EC50 values of 3.7 and 6.5 microM, respectively. The relative potencies of methyl iodide and chloropicrin were not significantly different but were 2.6 and 2.9 times more potent than methyl bromide, respectively. The EC50 values for all fumigants other than 1,3-D were significantly lower than that of methyl bromide. Combining each fumigant with 17% chloropicrin resulted in a synergistic interaction. The greatest increase in potency between the expected result and the actual result was a relative potency of 3.8 with the methyl bromide/chloropicrin combination. The smallest increase in efficacy was with propargyl bromide and chloropicrin, with a relative potency of 1.5. There was no significant difference between the EC50 values of methyl bromide/chloropicrin and methyl iodide/chloropicrin combinations. Combining 1,3-D with 17% chloropicrin resulted in an EC50 value for C. esculentus control similar to that of methyl iodide applied alone. PMID:15119599

  13. Ion Beam Micro-Sculpturing

    NASA Astrophysics Data System (ADS)

    Kubby, Joel Alan

    . The application of this analysis to the field of sputter induced pattern transfer in micro -electronics is discussed, where the results will be useful for prediction of fabrication procedures in the limit of small minimum feature size.

  14. Manufacture of micro fluidic devices by laser welding using thermal transfer printing techniques

    NASA Astrophysics Data System (ADS)

    Klein, R.; Klein, K. F.; Tobisch, T.; Thoelken, D.; Belz, M.

    2016-03-01

    Micro-fluidic devices are widely used today in the areas of medical diagnostics and drug research, as well as for applications within the process, electronics and chemical industry. Microliters of fluids or single cell to cell interactions can be conveniently analyzed with such devices using fluorescence imaging, phase contrast microscopy or spectroscopic techniques. Typical micro-fluidic devices consist of a thermoplastic base component with chambers and channels covered by a hermetic fluid and gas tight sealed lid component. Both components are usually from the same or similar thermoplastic material. Different mechanical, adhesive or thermal joining processes can be used to assemble base component and lid. Today, laser beam welding shows the potential to become a novel manufacturing opportunity for midsize and large scale production of micro-fluidic devices resulting in excellent processing quality by localized heat input and low thermal stress to the device during processing. For laser welding, optical absorption of the resin and laser wavelength has to be matched for proper joining. This paper will focus on a new approach to prepare micro-fluidic channels in such devices using a thermal transfer printing process, where an optical absorbing layer absorbs the laser energy. Advantages of this process will be discussed in combination with laser welding of optical transparent micro-fluidic devices.

  15. Microfluidic device based on a micro-hydrocyclone for particle-liquid separation.

    PubMed

    Bhardwaj, P; Bagdi, P; Sen, A K

    2011-12-01

    This paper presents theoretical analysis, design, simulation, fabrication and test of a microfluidic device ('Micro-hydrocyclone') for separation of micron and submicron size solid particles from liquid in a particle liquid mixture. A theoretical analysis of the micro-hydrocyclone is performed to understand the physics and develop suitable design models. The structure of the proposed device is designed based on the Bradley model, as it offers lower cut-size thus making it suitable for microfluidics applications. The operational parameters are derived from the dimensional group model. The particle separation process inside the micro-hydrocyclone is simulated by solving fluid flows using Navier-Stokes equations and particle dynamics using a Lagrangian approach in a Eulerian fluid. The influence of inlet velocity and density on separation efficiency is investigated. The device is fabricated with SU-8 photoresist on a PMMA substrate using a combination of photolithography and micro-milling. Experiments are performed to demonstrate particle-liquid separation using polystyrene microbeads suspended in PBS as the feed sample. The influence of inlet velocity and particle size on particle separation efficiency is measured and compared with that obtained from simulations and a good match was found. The proposed device can be easily integrated with micro-environments thus it is suitable for lab-on-chip and microsystems development. The device may have applications in chemical analysis, materials research, point-of-care, blood sample preparation and other biomedical applications.

  16. Bacterial adhesion and biofilm formation over a substrate with micro printed oily patches

    NASA Astrophysics Data System (ADS)

    Jalali, Maryam; Sheng, Jian

    2014-11-01

    Over the past few years, there has been a significant focus on the processes involved in biodegradation of crude oil. In prior studies, using soft lithography and surface functionalization, we have fabricated solid substrates with micro-scale chemical patterns, and applied them to studying the bacteria-surface interactions as well as the formation of biofilm over these micro-patterned surfaces. A strong correlation between biofilm morphology and substrate patterns was found. In our current work we investigate the bacterial adhesion and biofilm formation of hydrocarbon degrading bacteria on micro printed oily surfaces with different micro-scale textures. The oily patterns were formed by contact printing of crude oil on a glass substrate with PDMS stamps. The oil patterned surface is additionally combined with a microfluidics as its bottom substrate. This unique lab-on-a-chip device allows us to investigate the complex interactions microscopically and over a long time. Additionally, it allows us to conduct experiments to elucidate the dynamic interactions such as swimming, dispersion, attachment, detachment, and adsorption between bacteria and micro printed oily surfaces under flow conditions in-situ. The growth rates and morphology of bacterial colony and biofilm are also studied and reported.

  17. Bioinspired micro/nano fabrication on dental implant-bone interface

    NASA Astrophysics Data System (ADS)

    Wang, Feng; Shi, Liang; He, Wen-Xi; Han, Dong; Yan, Yan; Niu, Zhong-Ying; Shi, Sheng-Gen

    2013-01-01

    Pioneering research suggests fabricating a biomimetic interface with multiscaled surfacial architecture can greatly improve biomaterials' function and property. According to this inspiration, we chiefly single out and analyze the natural hierarchical micro/nano structure in rat's alveolar bone. Then, a combined hierarchical structure, i.e. micro-pits interlaced self-assemble TiO2 nanotubes of several tens of nanometers on dental implant's surface is developed. The as-prepared surface showed that hundreds of self-assembled TiO2 nanotubes were tightly arrayed with a diameter range of 30-50 nm, similar to collagen fibers within rat's mandible (60-80 nm). Meanwhile, this hierarchical micro/nano surface can provide a larger surface energy and roughness, a preferable hydrophilicity, a more adaptive mechanical property and adhesion work, a better bioactivity and biocompatibity, a superior attachment and growth of osteoblasts as compared to the smooth and purely micro-treated counterparts. The results indicated that this bioinspired micro/nano fabrication on dental implant-bone interface can be potentially applied in the update of dental implant in patients' clinical therapy and provide a new strategy for fabricating other osteocompatible materials.

  18. Microinjection of sigma-D-glucose standards and Amplex Red reagent on micro-arrays

    NASA Astrophysics Data System (ADS)

    Moerman, R.; van den Doel, L. Richard; Picioreanu, S.; Frank, J.; Marijnissen, Johannes P. A.; van Dedem, G. W. K.; Hjelt, Kari H.; Vellekoop, Michael J.; Sarro, Pasqualina M.; Young, Ian T.

    1999-06-01

    Intelligent Molecular Diagnostic Systems (IMDS)- The objective of this multidisciplinary research program is to design and develop an analytical system that is able to measure and interpret concentrations of various analytes which are dispensed on a micro-array. The analytes are detected by means of fluorescence or (chemi)luminescence measurement. Furthermore, the collected data are combined and interpreted using modern reasoning techniques. Micro-injection- Dispensing picoliters (pl) of reagents (enzymes, antibodies, etc.) and liquid samples on a micro-array requires special techniques. At the moment we are working on a technique which will allow for accurately dispensing liquid volumes less than 100 pl on a micro-array. Detection of (beta) -D-glucose- (beta) -D-glucose standards are dispensed on a micro-array, after which a solution of Amplex Red reagent, horse radish peroxidase (HARP), and glucose oxidase in a mixture of ethylene glycol and water is added. Ethylene glycol is added to prevent evaporation. The (beta) -D-glucose reacts with glucose oxidase to D-gluconolactone and H2O2. The H2O2 reacts with 10-acetyl-3,7-dihydroxyphenoxazine (Amplex Red) with a 1:1 stoichiometry to produce highly fluorescent resorufin. The formation of resorufin with time is followed with a Zeiss Axioskop microscope equipped with a KAF Photometrics CCD camera, in order to determine the sensitivity, concentrations, and volumes associated with the dispensed fluids.

  19. Micro/nano-mechanical sensors and actuators based on SOI-MEMS technology

    NASA Astrophysics Data System (ADS)

    Viet Dao, Dzung; Nakamura, Koichi; Thanh Bui, Tung; Sugiyama, Susumu

    2010-03-01

    MEMS (micro-electro-mechanical systems) technology has undergone almost 40 years of development, with significant technology advancement and successful commercialization of single-functional MEMS devices, such as pressure sensors, accelerometers, gyroscopes, microphones, micro-mirrors, etc. In this context of MEMS technology, this paper introduces our studies and developments of novel micro/nano-mechanical sensors and actuators based on silicon- on-insulator (SOI)-MEMS technology, as well as fundamental research on piezoresistive effects in single-crystal silicon nanowires (SiNWs). In the first area, novel mechanical sensors, such as 6-DOF micro-force moment sensors, multi-axis inertial sensors and micro-electrostatic actuators developed with SOI-MEMS technology will be presented. In the second area, we have combined atomic-level simulation and experimental evaluation methods to explain the giant piezoresistive effect in single crystalline SiNWs along different crystallographic orientations. This discovery is significant for developing more highly sensitive and miniaturized mechanical sensors in the near future.

  20. High resolution micro-XRF maps of iron oxides inside sensory dendrites of putative avian magnetoreceptors

    NASA Astrophysics Data System (ADS)

    Falkenberg, G.; Fleissner, G. E.; Fleissner, G. U. E.; Schuchardt, K.; Kühbacher, M.; Chalmin, E.; Janssens, K.

    2009-09-01

    Iron mineral containing sensory dendrites in the inner lining of the upper beak of homing pigeons [1] and various bird species [2] are the first candidate structures for an avian magnetic field receptor. A new concept of magnetoreception [3, 4] is based on detailed ultra-structural optical and electron microscopy analyses in combination with synchrotron radiation microscopic X-ray fluorescence analysis (micro-XRF) and microscopic X-ray absorption near edge structures (micro-XANES). Several behavioral experiments [5, 6] and first mathematical simulations [6] affirm our avian magnetoreceptor model. The iron minerals inside the dendrites are housed in three different subcellular compartments (bullets, platelets, vesicles), which could be clearly resolved and identified by electron microscopy on ultrathin sections [1, 3]. Micro-XRF and micro-XANES data obtained at HASYLAB beamline L added information about the elemental distribution and Fe speciation [3], but are averaged over the complete dendrite due to limited spatial resolution. Here we present recently performed micro-XRF maps with sub-micrometer resolution (ESRF ID21), which reveal for the first time subcellular structural information from almost bulk-like dendrite sample material. Due to the thickness of 30 μm the microarchitecture of the dendrites can be considered as undisturbed and artefacts introduced by sectioning might be widely reduced.

  1. Inline chemical process analysis in micro-plants based on thermoelectric flow and impedimetric sensors

    NASA Astrophysics Data System (ADS)

    Jacobs, T.; Kutzner, C.; Kropp, M.; Brokmann, G.; Lang, W.; Steinke, A.; Kienle, A.; Hauptmann, P.

    2010-10-01

    In micro-plants, as used in chemical micro-process engineering, an integrated inline analytics is regarded as an important factor for the development and optimization of chemical processes. Up to now, there is a lack of sensitive, robust and low-priced micro-sensors for monitoring mixing and chemical conversion in micro-fluidic channels. In this paper a novel sensor system combining an impedimetric sensor and a novel pressure stable thermoelectric flow sensor for monitoring chemical reactions in micro-plants is presented. The CMOS-technology-based impedimetric sensor mainly consists of two capacitively coupled interdigital electrodes on a silicon chip. The thermoelectric flow sensor consists of a heater in between two thermopiles on a perforated membrane. The pulsed and constant current feeds of the heater were analyzed. Both sensors enable the analysis of chemical conversion by means of changes in the thermal and electrical properties of the liquid. The homogeneously catalyzed synthesis of n-butyl acetate as a chemical model system was studied. Experimental results revealed that in an overpressure regime, relative changes of less than 1% in terms of thermal and electrical properties can be detected. Furthermore, the transition from one to two liquid phases accompanied by the change in slug flow conditions could be reproducibly detected.

  2. Electrochemical detection of lung cancer specific microRNAs using 3D DNA origami nanostructures.

    PubMed

    Liu, Shuopeng; Su, Wenqiong; Li, Zonglin; Ding, Xianting

    2015-09-15

    Recent reports have indicated that aberrant expression of microRNAs is highly correlated with occurrence of lung cancer. Therefore, highly sensitive detection of lung cancer specific microRNAs provides an attractive approach in lung cancer early diagnostics. Herein, we designed 3D DNA origami structure that enables electrochemical detection of lung cancer related microRNAs. The 3D DNA origami structure is constituted of a ferrocene-tagged DNA of stem-loop structure combined with a thiolated tetrahedron DNA nanostructure at the bottom. The top portion hybridized with the lung cancer correlated microRNA, while the bottom portion was self-assembled on gold disk electrode surface, which was modified with gold nanoparticles (Au NPs) and blocked with mercaptoethanol (MCH). The preparation process and the performance of the proposed electrochemical genosensor were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Under the optimal conditions, the developed genosensor had a detection limit of 10 pM and a good linearity with microRNA concentration ranging from 100 pM to 1 µM, which showed a great potential in highly sensitive clinical cancer diagnosis application.

  3. Characteristic ruptures of micro-seismic hydraulic fractures

    NASA Astrophysics Data System (ADS)

    Viegas, G. F.; Smith-Boughner, L.; Urbancic, T.; Baig, A. M.

    2015-12-01

    Hydraulic fracturing is a process that involves the injection of fluids above lithostatic pressures to increase permeability of rocks at depth. During the fracturing process thousands of micro-seismic events are generated as the fracture front propagates outwards from the injection point. Sand or glass beads are frequently injected later in the stage to prop the fractures and maintain flow paths open. Because injection progresses in time and space changing the in situ characteristics the generated seismic events show a combination of seismic signatures between two end members: Coulomb stress transfer on favorably oriented fractures and fluid-induced tensile fractures. In this study we investigate the failure process of ~27,000 micro-seismic fractures induced during a hydraulic fracturing shale completion program. Our goal is to identify spatial and temporal distribution of families of events with similar characteristic rupture behaviors, for different injection phases and relative locations based on either rock formation, depth, source mechanism, fracture plane orientation, stress drop, etc., to classify distinct dynamic failure processes. In our analysis we estimate static and dynamic stress drop, radiated energy, seismic efficiency, moment tensor, fracture plane orientation, slip direction and rupture velocity. On average, the micro-seismic events have low radiated energy, low dynamic stress and low seismic efficiency failing in overshoot mode, with slow rupture velocities consistent with failure on fluid lubricated fractures with decreased friction resistance. Slip is accommodated on fracture planes with orientations dominated by the rock fabric and not always optimally oriented to the regional stress field. Subtle source characteristic differences can be identified: Events occurring in deeper formations tend to have faster rupture velocities and are more efficient in radiating energy. Variations in rupture velocity tend to correlate with variation in depth

  4. Micro-Grooving and Micro-Threading Tools for Fabricating Curvilinear Features

    SciTech Connect

    ADAMS,DAVID P.; VASILE,MICHAEL J.; KRISHNAN,A.S.M.

    2000-07-24

    This paper presents techniques for fabricating microscopic, curvilinear features in a variety of workpiece materials. Micro-grooving and micro-threading tools having cutting widths as small as 13 {micro}m are made by focused ion beam sputtering and used for ultra-precision machining. Tool fabrication involves directing a 20 keV gallium beam at polished cylindrical punches made of cobalt M42 high-speed steel or C2 tungsten carbide to create a number of critically aligned facets. Sputtering produces rake facets of desired angle and cutting edges having radii of curvature equal to 0.4 {micro}m. Clearance for minimizing frictional drag of a tool results from a particular ion beam/target geometry that accounts for the sputter yield dependence on incidence angle. It is believed that geometrically specific cutting tools of this dimension have not been made previously. Numerically controlled, ultra-precision machining with micro-grooving tools results in a close match between tool width and feature size. Microtools are used to machine 13 {micro}m wide, 4 {micro}m deep, helical grooves in polymethyl methacrylate and 6061 Al cylindrical workplaces. Micro-grooving tools are also used to fabricate sinusoidal cross-section features in planar metal samples.

  5. Ion Beam Sputter Fabrication of Micro-Grooving and Micro-Threading Tools

    SciTech Connect

    ADAMS,DAVID P.; VASILE,M.J.; KRISHNAN,A.S.M.

    1999-11-05

    This paper presents techniques for fabricating microscopic, nonplanar features in a variety of materials. Micro-grooving and micro-threading tools having cutting dimensions of 10-30{micro}m are made by focused ion beam sputtering and used in ultra-precision machining. Tool fabrication involves directing a 20 keV gallium beam at polished cylindrical punches made of cobalt M42 high-speed steel or C2 tungsten carbide. This creates cutting edges having radii of curvature less than 0.4 {micro}m, and rake features similar to conventional lathe tools. Clearance for minimizing frictional drag of a tool results from the sputter yield dependence on ion herd target incidence angle. Numerically controlled, ultra-precision machining with micro-grooving tools results in a close matching between tool width and feature size. Microtools controllably machine 13 {micro}m wide, 4 {micro}m deep, helical grooves in polymethyl methacrylate and 6061-T6 Al cylindrical substrates. Micro-grooving tools also fabricate sinusoidal waveform features in polished metal substrates.

  6. Height reversal of Si micro dot and well patterns during Si nanowire formation by Ag-assisted chemical etching

    NASA Astrophysics Data System (ADS)

    Yamaura, Daichi; Takeuchi, Koji; Lu, Zhiqiang; Arai, Yuki; Ogino, Toshio

    2015-05-01

    The Si nanowire (Si-NW) formation process has been studied to develop a new anode material for lithium ion batteries. Si-NWs were prepared by a combination of electroless metal deposition (EMD) of Ag and metal-assisted chemical etching (Mac etching) on Si substrates that have micro dot and well patterns with respect to their height. During the fabrication of Si-NWs, height reversal occurred in the micro dot and well patterns, and Si micro- and nano-hybrid systems were fabricated. We also observed structural changes of the Si micro- and nano-hybrid structures during the electrochemical charge/discharge process of lithium ions, and showed that this hybrid system is robust for the volume change accompanied with the lithiation/delithiation reaction.

  7. Nanocrystalline diamond micro-anvil grown on single crystal diamond as a generator of ultra-high pressures

    NASA Astrophysics Data System (ADS)

    Samudrala, Gopi K.; Moore, Samuel L.; Velisavljevic, Nenad; Tsoi, Georgiy M.; Baker, Paul A.; Vohra, Yogesh K.

    2016-09-01

    By combining mask-less lithography and chemical vapor deposition (CVD) techniques, a novel two-stage diamond anvil has been fabricated. A nanocrystalline diamond (NCD) micro-anvil 30 μ m in diameter was grown at the center of a [100]-oriented, diamond anvil by utilizing microwave plasma CVD method. The NCD micro-anvil has a diamond grain size of 115 nm and micro-focused Raman and X-ray Photoelectron spectroscopy analysis indicate sp3-bonded diamond content of 72%. These CVD grown NCD micro-anvils were tested in an opposed anvil configuration and the transition metals osmium and tungsten were compressed to high pressures of 264 GPa in a diamond anvil cell.

  8. The influence of selected design and operating parameters on the dynamics of the steam micro-turbine

    NASA Astrophysics Data System (ADS)

    Żywica, Grzegorz; Kiciński, Jan

    2015-10-01

    The topic of the article is the analysis of the influence of selected design parameters and operating conditions on the radial steam micro-turbine, which was adapted to operate with low-boiling agent in the Organic Rankine Cycle (ORC). In the following parts of this article the results of the thermal load analysis, the residual unbalance and the stiffness of bearing supports are discussed. Advanced computational methods and numerical models have been used. Computational analysis showed that the steam micro-turbine is characterized by very good dynamic properties and is resistant to extreme operating conditions. The prototype of micro-turbine has passed a series of test calculations. It has been found that it can be subjected to experimental research in the micro combined heat and power system.

  9. Micro-Electro-Mechanical-Systems-Based Micro-Ro-Boat Utilizing Steam as Propulsion Power

    NASA Astrophysics Data System (ADS)

    Choi, Ju Chan; Choi, Young Chan; Kyoo Lee, June; Kong, Seong Ho

    2012-06-01

    We report the design and fabrication of a micro-electro-mechanical-systems (MEMS)-based microactuator, that floats on the surface of water and is driven by steam. We named the actuator “micro-Ro-boat”, a compound word created from the words “robot” and “boat”. The MEMS-based micro-Ro-boat utilizes steam as the propulsion power, giving it a high speed and long lifetime. A hydrophobic surface has been utilized for the wing of the actuator to enhance the buoyancy. Instead of using gas or fuel, the proposed micro-Ro-boat utilizes steam form electrically heated water. The velocity of the micro-Ro-boat is in the range of 0.5-2 cm/s and the maximum loading capability for a device size of 10 ×10 mm2 is 0.4 g.

  10. Fully integrated micro-separator with soft-magnetic micro-pillar arrays for filtrating lymphocytes.

    PubMed

    Dong, Tao; Su, Qianhua; Yang, Zhaochu; Karlsen, Frank; Jakobsen, Henrik; Egeland, Eirik Bentzen; Hjelseth, Snorre

    2010-01-01

    A fully integrated micro-separator with soft-magnetic micro-pillar arrays has been developed, which merely employs one independent Lab-On-Chip to realize the lymphocytes isolation from the human whole blood. The simulation, fabrication and experiment are executed to realize this novel microseparator. The simulation results show that, the soft-magnetic micro-pillars array can amplify and redistribute the electromagnetic field generated by the microcoils. The tests certify desirable separation efficiency can be realized using this new separator at low current. No extra cooling system is required for such a micro-separator. This micro-separator can also be used to separate other target cells or particles with the same principle. PMID:21096497

  11. Laser welding of micro plastic parts

    NASA Astrophysics Data System (ADS)

    Haberstroh, E.; Hoffmann, W.-M.

    2007-02-01

    Most welding processes for plastics do not meet the demands of micro technology and thus cannot be applied in this innovative industrial sector. One of the few techniques which are applicable in this sector is the laser transmission welding, which has distinctive advantages like low mechanical and thermal load of the joining parts. This makes the laser particularly suitable for the welding of micro plastics parts. Thereby, contour welding is a process variant of laser transmission welding enabling the welding of complex and even three-dimensional weld contours. But so far it has not yet been applied for welding plastics parts of micro scale in the industrial practice. Recent research at the Institute of Plastics Processing (IKV) at the RWTH Aachen University shows the feasibility of this process to weld small and complex micro parts. Good mechanical properties can be achieved. However, it is necessary to apply measures to reduce the formation of flash. Moreover, it can be shown that there is a strong influence of some material parameters on the laser welding process so that some plastics are more suitable than others for the contour welding in micro technology.

  12. SUB 1-Millimeter Size Fresnel Micro Spectrometer

    NASA Technical Reports Server (NTRS)

    Park, Yeonjoon; Koch, Laura; Song, Kyo D.; Park, Sangloon; King, Glen; Choi, Sang

    2010-01-01

    An ultra-small micro spectrometer with less than 1mm diameter was constructed using Fresnel diffraction. The fabricated spectrometer has a diameter of 750 nmicrometers and a focal length of 2.4 mm at 533nm wavelength. The micro spectrometer was built with a simple negative zone plate that has an opaque center with an ecliptic shadow to remove the zero-order direct beam to the aperture slit. Unlike conventional approaches, the detailed optical calculation indicates that the ideal spectral resolution and resolving power do not depend on the miniaturized size but only on the total number of rings. We calculated 2D and 3D photon distribution around the aperture slit and confirmed that improved micro-spectrometers below 1mm size can be built with Fresnel diffraction. The comparison between mathematical simulation and measured data demonstrates the theoretical resolution, measured performance, misalignment effect, and improvement for the sub-1mm Fresnel micro-spectrometer. We suggest the utilization of an array of micro spectrometers for tunable multi-spectral imaging in the ultra violet range.

  13. Micro-Pixel Image Position Sensing Testbed

    NASA Technical Reports Server (NTRS)

    Nemati, Bijan; Shao, Michael; Zhai, Chengxing; Erlig, Hernan; Wang, Xu; Goullioud, Renaud

    2011-01-01

    The search for Earth-mass planets in the habitable zones of nearby Sun-like stars is an important goal of astrophysics. This search is not feasible with the current slate of astronomical instruments. We propose a new concept for microarcsecond astrometry which uses a simplified instrument and hence promises to be low cost. The concept employs a telescope with only a primary, laser metrology applied to the focal plane array, and new algorithms for measuring image position and displacement on the focal plane. The required level of accuracy in both the metrology and image position sensing is at a few micro-pixels. We have begun a detailed investigation of the feasibility of our approach using simulations and a micro-pixel image position sensing testbed called MCT. So far we have been able to demonstrate that the pixel-to-pixel distances in a focal plane can be measured with a precision of 20 micro-pixels and image-to-image distances with a precision of 30 micro-pixels. We have also shown using simulations that our image position algorithm can achieve accuracy of 4 micro-pixels in the presence of lambda/20 wavefront errors.

  14. Methods for fabricating a micro heat barrier

    DOEpatents

    Marshall, Albert C.; Kravitz, Stanley H.; Tigges, Chris P.; Vawter, Gregory A.

    2004-01-06

    Methods for fabricating a highly effective, micron-scale micro heat barrier structure and process for manufacturing a micro heat barrier based on semiconductor and/or MEMS fabrication techniques. The micro heat barrier has an array of non-metallic, freestanding microsupports with a height less than 100 microns, attached to a substrate. An infrared reflective membrane (e.g., 1 micron gold) can be supported by the array of microsupports to provide radiation shielding. The micro heat barrier can be evacuated to eliminate gas phase heat conduction and convection. Semi-isotropic, reactive ion plasma etching can be used to create a microspike having a cusp-like shape with a sharp, pointed tip (<0.1 micron), to minimize the tip's contact area. A heat source can be placed directly on the microspikes. The micro heat barrier can have an apparent thermal conductivity in the range of 10.sup.-6 to 10.sup.-7 W/m-K. Multiple layers of reflective membranes can be used to increase thermal resistance.

  15. Micro-grooved heat transfer combustor wall

    NASA Technical Reports Server (NTRS)

    Ward, Steven D. (Inventor)

    1994-01-01

    A gas turbine engine hot section combustor liner is provided a non-film cooled portion of a heat transfer wall having a hot surface and a plurality of longitudinally extending micro-grooves disposed in the portion of the wall along the hot surface in a direction parallel to the direction of the hot gas flow. The depth of the micro-grooves is very small and on the order of magnitude of a predetermined laminar sublayer of a turbulent boundary layer. The micro-grooves are sized so as to inhibit heat transfer from the hot gas flow to the hot surface of the wall while reducing NOx emissions of the combustor relative to an otherwise similar combustor having a liner wall portion including film cooling apertures. In one embodiment the micro-grooves are about 0.001 inches deep and have a preferred depth range of from about 0.001 inches to 0.005 inches and which are square, rectangular, or triangular in cross-section and the micro-grooves are spaced about one width apart.

  16. Micro-fabrication Techniques for Target Components

    SciTech Connect

    Miles, R; Hamilton, J; Crawford, J; Ratti, S; Trevino, J; Graff, T; Stockton, C; Harvey, C

    2008-06-10

    Micro-fabrication techniques, derived from the semi-conductor industry, can be used to make a variety of useful mechanical components for targets. A selection of these components including supporting cooling arms for prototype cryogenic inertial confinement fusion targets, stepped and graded density targets for materials dynamics experiments are described. Micro-fabrication enables cost-effective, simultaneous fabrication of multiple high-precision components with complex geometries. Micro-fabrication techniques such as thin-film deposition, photo-lithographic patterning and etch processes normally used in the semi-conductor manufacture industry, can be exploited to make useful mechanical target components. Micro-fabrication processes have in recent years been used to create a number of micro-electro-mechanical systems (MEMS) components such as pressure sensors, accelerometers, ink jet printer heads, microfluidics platforms and the like. These techniques consist primarily of deposition of thin films of material, photo-lithographic patterning and etching processes performed sequentially to produce three dimensional structures using essentially planar processes. While the planar technology can be limiting in terms of the possible geometries of the final product, advantages of using these techniques include the ability to make multiple complex structures simultaneously and cost-effectively. Target components fabricated using these techniques include the supporting cooling arms for cryogenic prototype fusion ignition targets, stepped targets for equation-of-state experiments, and graded density reservoirs for material strength experiments.

  17. Interpreting pathologies in extant and extinct archosaurs using micro-CT

    PubMed Central

    Garwood, Russell J.; Lowe, Tristan; Withers, Philip J.; Manning, Phillip L.

    2015-01-01

    Palaeopathology offers unique insight to the healing strategies of extinct organisms, permitting questions concerning bone physiology to be answered in greater depth. Unfortunately, most palaeopathological studies are confined to external morphological interpretations due to the destructive nature of traditional methods of study. This limits the degree of reliable diagnosis and interpretation possible. X-ray MicroTomography (micro-CT, XMT) provides a non-destructive means of analysing the internal three-dimensional structure of pathologies in both extant and extinct individuals, at higher resolutions than possible with medical scanners. In this study, we present external and internal descriptions of pathologies in extant and extinct archosaurs using XMT. This work demonstrates that the combination of external/internal diagnosis that X-ray microtomography facilitates is crucial when differentiating between pathological conditions. Furthermore, we show that the use of comparative species, both through direct analysis and from the literature, provides key information for diagnosing between vertebrate groups in the typical pathological conditions and physiological processes. Micro-CT imaging, combined with comparative observations of extant species, provides more detailed and reliable interpretation of palaeopathologies. Micro-CT is an increasingly accessible tool, which will provide key insights for correctly interpreting vertebrate pathologies in the future. PMID:26246971

  18. Drag reduction using metallic engineered surfaces with highly ordered hierarchical topographies: nanostructures on micro-riblets

    NASA Astrophysics Data System (ADS)

    Kim, Taekyung; Shin, Ryung; Jung, Myungki; Lee, Jinhyung; Park, Changsu; Kang, Shinill

    2016-03-01

    Durable drag-reduction surfaces have recently received much attention, due to energy-saving and power-consumption issues associated with harsh environment applications, such as those experienced by piping infrastructure, ships, aviation, underwater vehicles, and high-speed ground vehicles. In this study, a durable, metallic surface with highly ordered hierarchical structures was used to enhance drag-reduction properties, by combining two passive drag-reduction strategies: an air-layer effect induced by nanostructures and secondary vortex generation by micro-riblet structures. The nanostructures and micro-riblet structures were designed to increase slip length. The top-down fabrication method used to form the metallic hierarchical structures combined laser interference lithography, photolithography, thermal reflow, nanoimprinting, and pulse-reverse-current electrochemical deposition. The surfaces were formed from nickel, which has high hardness and corrosion resistance, making it suitable for use in harsh environments. The drag-reduction properties of various metal surfaces were investigated based on the surface structure: a bare surface, a nanostructured surface, a micro-riblet surface, and a hierarchically structured surface of nanostructures on micro-riblets.

  19. Cellular Reprogramming Using Defined Factors and MicroRNAs.

    PubMed

    Eguchi, Takanori; Kuboki, Takuo

    2016-01-01

    Development of human bodies, organs, and tissues contains numerous steps of cellular differentiation including an initial zygote, embryonic stem (ES) cells, three germ layers, and multiple expertized lineages of cells. Induced pluripotent stem (iPS) cells have been recently developed using defined reprogramming factors such as Nanog, Klf5, Oct3/4 (Pou5f1), Sox2, and Myc. This outstanding innovation is largely changing life science and medicine. Methods of direct reprogramming of cells into myocytes, neurons, chondrocytes, and osteoblasts have been further developed using modified combination of factors such as N-myc, L-myc, Sox9, and microRNAs in defined cell/tissue culture conditions. Mesenchymal stem cells (MSCs) and dental pulp stem cells (DPSCs) are also emerging multipotent stem cells with particular microRNA expression signatures. It was shown that miRNA-720 had a role in cellular reprogramming through targeting the pluripotency factor Nanog and induction of DNA methyltransferases (DNMTs). This review reports histories, topics, and idea of cellular reprogramming.

  20. A mechanically assisted heat pipe using micro-pumps

    SciTech Connect

    Wong, J.L.; Campbell, G.; Hassapis, C.; Chang, W.S.

    1996-12-31

    A new mechanically assisted heat pipe has been developed and tested by the authors that combines the high performance of a pumped fluid loop with the reliability of passive heat pipes. The new unit employs micro-pumps inside a passive heat pipe to enhance the return of working fluid from the condenser to the evaporator, and thereby increases the capability of the system. This hybrid device is lighter, smaller and handles higher heat flux compared with a passive heat pipe of similar weight and dimensions. Best of all, if the mechanical pump fails, the heat transport will be impaired, but not totally paralyzed, allowing some form of lower level operation. This micro-pump design installs fins at critical locations inside the heat pipe. These fins can be parallel (flag) or perpendicular (flap) to the flow direction. By vibrating these fins in a motion similar to dolphin kicks for the flaps, and in a motion similar to a fishtail for the flags, these fins were found capable of pumping the working fluid effectively. The size and geometry of these fins were tested extensively. Several actuation approaches were examined. The results of these tests are presented in this paper.