DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Bin; Brown, Chance C.; Huang, Jingsong

Ionicity plays an important role in determining material properties, as well as optoelectronic performance of organometallic trihalide perovskites (OTPs). Ion migration in OTP films has recently been under intensive investigation by various scanning probe microscopy (SPM) techniques. Controversial findings regarding the role of grain boundaries (GBs) associated with ion migration are often encountered, likely as a result of feedback errors and topographic effects common in to SPM. In this work, electron microscopy and spectroscopy (scanning transmission electron microscopy/electron energy loss spectroscopy) are combined with a novel, open-loop, band-excitation, (contact) Kelvin probe force microscopy (BE-KPFM and BE-cKPFM), in conjunction with abmore » initio molecular dynamics simulations to examine the ion behavior in the GBs of CH 3NH 3PbI 3 perovskite films. Furthermore, this combination of diverse techniques provides a deeper understanding of the differences between ion migration within GBs and interior grains in OTP films. Our work demonstrates that ion migration can be significantly enhanced by introducing additional mobile Cl - ions into GBs. The enhancement of ion migration may serve as the first step toward the development of high-performance electrically and optically tunable memristors and synaptic devices.« less

Catalytic reaction processes revealed by scanning probe microscopy. [corrected].

PubMed

Jiang, Peng; Bao, Xinhe; Salmeron, Miquel

2015-05-19

Heterogeneous catalysis is of great importance for modern society. About 80% of the chemicals are produced by catalytic reactions. Green energy production and utilization as well as environmental protection also need efficient catalysts. Understanding the reaction mechanisms is crucial to improve the existing catalysts and develop new ones with better activity, selectivity, and stability. Three components are involved in one catalytic reaction: reactant, product, and catalyst. The catalytic reaction process consists of a series of elementary steps: adsorption, diffusion, reaction, and desorption. During reaction, the catalyst surface can change at the atomic level, with roughening, sintering, and segregation processes occurring dynamically in response to the reaction conditions. Therefore, it is imperative to obtain atomic-scale information for understanding catalytic reactions. Scanning probe microscopy (SPM) is a very appropriate tool for catalytic research at the atomic scale because of its unique atomic-resolution capability. A distinguishing feature of SPM, compared to other surface characterization techniques, such as X-ray photoelectron spectroscopy, is that there is no intrinsic limitation for SPM to work under realistic reaction conditions (usually high temperature and high pressure). Therefore, since it was introduced in 1981, scanning tunneling microscopy (STM) has been widely used to investigate the adsorption, diffusion, reaction, and desorption processes on solid catalyst surfaces at the atomic level. STM can also monitor dynamic changes of catalyst surfaces during reactions. These invaluable microscopic insights have not only deepened the understanding of catalytic processes, but also provided important guidance for the development of new catalysts. This Account will focus on elementary reaction processes revealed by SPM. First, we will demonstrate the power of SPM to investigate the adsorption and diffusion process of reactants on catalyst surfaces at the atomic level. Then the dynamic processes, including surface reconstruction, roughening, sintering, and phase separation, studied by SPM will be discussed. Furthermore, SPM provides valuable insights toward identifying the active sites and understanding the reaction mechanisms. We also illustrate here how both ultrahigh vacuum STM and high pressure STM provide valuable information, expanding the understanding provided by traditional surface science. We conclude with highlighting remarkable recent progress in noncontact atomic force microscopy (NC-AFM) and inelastic electron tunneling spectroscopy (IETS), and their impact on single-chemical-bond level characterization for catalytic reaction processes in the future.

Quantitative analysis of the local phase transitions induced by the laser heating

DOE PAGES

Levlev, Anton V.; Susner, Michael A.; McGuire, Michael A.; ...

2015-11-04

Functional imaging enabled by scanning probe microscopy (SPM) allows investigations of nanoscale material properties under a wide range of external conditions, including temperature. However, a number of shortcomings preclude the use of the most common material heating techniques, thereby limiting precise temperature measurements. Here we discuss an approach to local laser heating on the micron scale and its applicability for SPM. We applied local heating coupled with piezoresponse force microscopy and confocal Raman spectroscopy for nanoscale investigations of a ferroelectric-paraelectric phase transition in the copper indium thiophosphate layered ferroelectric. Bayesian linear unmixing applied to experimental results allowed extraction of themore » Raman spectra of different material phases and enabled temperature calibration in the heated region. Lastly, the obtained results enable a systematic approach for studying temperature-dependent material functionalities in heretofore unavailable temperature regimes.« less

A novel design of a scanning probe microscope integrated with an ultramicrotome for serial block-face nanotomography

NASA Astrophysics Data System (ADS)

Efimov, Anton E.; Agapov, Igor I.; Agapova, Olga I.; Oleinikov, Vladimir A.; Mezin, Alexey V.; Molinari, Michael; Nabiev, Igor; Mochalov, Konstantin E.

2017-02-01

We present a new concept of a combined scanning probe microscope (SPM)/ultramicrotome apparatus. It enables "slice-and-view" scanning probe nanotomography measurements and 3D reconstruction of the bulk sample nanostructure from series of SPM images after consecutive ultrathin sections. The sample is fixed on a flat XYZ scanning piezostage mounted on the ultramicrotome arm. The SPM measuring head with a cantilever tip and a laser-photodiode tip detection system approaches the sample for SPM measurements of the block-face surface immediately after the ultramicrotome sectioning is performed. The SPM head is moved along guides that are also fixed on the ultramicrotome arm. Thereby, relative dysfunctional displacements of the tip, the sample, and the ultramicrotome knife are minimized. The design of the SPM head enables open frontal optical access to the sample block-face adapted for high-resolution optical lenses for correlative SPM/optical microscopy applications. The new system can be used in a wide range of applications for the study of 3D nanostructures of biological objects, biomaterials, polymer nanocomposites, and nanohybrid materials in various SPM and optical microscopy measuring modes.

The combination of scanning electron and scanning probe microscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sapozhnikov, I. D.; Gorbenko, O. M., E-mail: gorolga64@gmail.com; Felshtyn, M. L.

2016-06-17

We suggest the SPM module to combine SEM and SPM methods for studying surfaces. The module is based on the original mechanical moving and scanning system. The examples of studies of the steel surface microstructure in both SEM and SPM modes are presented.

New Algorithm to Enable Construction and Display of 3D Structures from Scanning Probe Microscopy Images Acquired Layer-by-Layer.

PubMed

Deng, William Nanqiao; Wang, Shuo; Ventrici de Souza, Joao; Kuhl, Tonya L; Liu, Gang-Yu

2018-06-25

Scanning probe microscopy (SPM), such as atomic force microscopy (AFM), is widely known for high-resolution imaging of surface structures and nanolithography in two dimensions (2D), providing important physical insights into surface science and material science. This work reports a new algorithm to enable construction and display of layer-by-layer 3D structures from SPM images. The algorithm enables alignment of SPM images acquired during layer-by-layer deposition and removal of redundant features and faithfully constructs the deposited 3D structures. The display uses a "see-through" strategy to enable the structure of each layer to be visible. The results demonstrate high spatial accuracy as well as algorithm versatility; users can set parameters for reconstruction and display as per image quality and research needs. To the best of our knowledge, this method represents the first report to enable SPM technology for 3D imaging construction and display. The detailed algorithm is provided to facilitate usage of the same approach in any SPM software. These new capabilities support wide applications of SPM that require 3D image reconstruction and display, such as 3D nanoprinting and 3D additive and subtractive manufacturing and imaging.

Three-dimensional nanoscale imaging by plasmonic Brownian microscopy

NASA Astrophysics Data System (ADS)

Labno, Anna; Gladden, Christopher; Kim, Jeongmin; Lu, Dylan; Yin, Xiaobo; Wang, Yuan; Liu, Zhaowei; Zhang, Xiang

2017-12-01

Three-dimensional (3D) imaging at the nanoscale is a key to understanding of nanomaterials and complex systems. While scanning probe microscopy (SPM) has been the workhorse of nanoscale metrology, its slow scanning speed by a single probe tip can limit the application of SPM to wide-field imaging of 3D complex nanostructures. Both electron microscopy and optical tomography allow 3D imaging, but are limited to the use in vacuum environment due to electron scattering and to optical resolution in micron scales, respectively. Here we demonstrate plasmonic Brownian microscopy (PBM) as a way to improve the imaging speed of SPM. Unlike photonic force microscopy where a single trapped particle is used for a serial scanning, PBM utilizes a massive number of plasmonic nanoparticles (NPs) under Brownian diffusion in solution to scan in parallel around the unlabeled sample object. The motion of NPs under an evanescent field is three-dimensionally localized to reconstruct the super-resolution topology of 3D dielectric objects. Our method allows high throughput imaging of complex 3D structures over a large field of view, even with internal structures such as cavities that cannot be accessed by conventional mechanical tips in SPM.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Somnath, Suhas; Collins, Liam; Matheson, Michael A.

We develop and implement a multifrequency spectroscopy and spectroscopic imaging mode, referred to as general dynamic mode (GDM), that captures the complete spatially- and stimulus dependent information on nonlinear cantilever dynamics in scanning probe microscopy (SPM). GDM acquires the cantilever response including harmonics and mode mixing products across the entire broadband cantilever spectrum as a function of excitation frequency. GDM spectra substitute the classical measurements in SPM, e.g. amplitude and phase in lock-in detection. Here, GDM is used to investigate the response of a purely capacitively driven cantilever. We use information theory techniques to mine the data and verify themore » findings with governing equations and classical lock-in based approaches. We explore the dependence of the cantilever dynamics on the tip–sample distance, AC and DC driving bias. This approach can be applied to investigate the dynamic behavior of other systems within and beyond dynamic SPM. In conclusion, GDM is expected to be useful for separating the contribution of different physical phenomena in the cantilever response and understanding the role of cantilever dynamics in dynamic AFM techniques.« less

Bias stress in PDI-CN2 and P3HT studied with Kelvin Probe Force Microscopy

NASA Astrophysics Data System (ADS)

Cao, Minxuan; Moscatello, Jason; Castaneda, Chloe; Xue, Binglan; Usluer, Ozlem; Briseno, Alejandro; Aidala, Katherine

We have developed a technique that uses scanning probe microscopy (SPM) to study the real-time injection and extraction of charge carriers in organic semiconductor devices. We investigate PDI-CN2 and P3HT in a back gate field effect transistor geometry with gold electrodes. By positioning the SPM tip at an individual location and using Kelvin probe microscopy to record the potential over time, we can record how the charge carriers respond to changing the gate voltage while the source and drain electrodes are grounded. We see relatively fast screening when carriers are injected into the film. The screening is slower when carriers must escape from traps to exit the film. By incrementally stepping the gate voltage, we can probe different trap depths. By repeating the measurement, we observe the development of longer lived trap states, shown by the longer time recorded to fully screen the gate voltage. This work is supported by NSF Grant DMR-0955348, and the Center for Heirarchical Manufacturing at the University of Massachusetts, Amherst (NSF CMMI-1025020).

Scanning probe microscopy of biomedical interfaces

NASA Astrophysics Data System (ADS)

Vansteenkiste, S. O.; Davies, M. C.; Roberts, C. J.; Tendler, S. J. B.; Williams, P. M.

1998-02-01

The development of the scanning probe microscopes over the past decade has provided a number of exciting new surface analytical techniques making a significant progress in the characterisation of biomedical interfaces. In this review, several examples are presented to illustrate that SPM is a powerful and promising tool for surface investigations including biomolecules, cell membranes, polymers and even living cells. The ability of the SPM instrument to monitor adhesion phenomena and provide quantitative information about intermolecular interactions is also described. Moreover, the huge potential of the scanning probe microscopes to study dynamic processes at interfaces under nearly physiological conditions is highlighted. Novel applications in the field of biochemistry, microbiology, biomaterial engineering, drug delivery and even medicine are discussed.

Humidity Effect on Nanoscale Electrochemistry in Solid Silver Ion Conductors and the Dual Nature of Its Locality

DOE PAGES

Yang, Sangmo; Strelcov, Evgheni; Paranthaman, Mariappan Parans; ...

2015-01-07

Scanning probe microscopy (SPM) is a powerful tool to investigate electrochemistry in nanoscale volumes. While most SPM-based studies have focused on reactions at the tip-surface junction, charge and mass conservation requires coupled and intrinsically non-local cathodic and anodic processes that can be significantly affected by ambient humidity. Here, we explore the role of water in both cathodic and anodic processes, associated charge transport, and topographic volume changes depending on the polarity of tip bias. The first-order reversal curve current-voltage technique combined with simultaneous detection of the sample topography, referred to as FORC-IVz, was applied to a silver solid ion conductor.more » We found that the protons generated from water affect silver ionic conduction, silver particle formation and dissolution, and mechanical integrity of the material. This work highlights the dual nature (simultaneously local and non-local) of electrochemical SPM studies, which should be considered for comprehensive understanding of nanoscale electrochemistry.« less

Humidity effect on nanoscale electrochemistry in solid silver ion conductors and the dual nature of its locality.

PubMed

Yang, Sang Mo; Strelcov, Evgheni; Paranthaman, M Parans; Tselev, Alexander; Noh, Tae Won; Kalinin, Sergei V

2015-02-11

Scanning probe microscopy (SPM) is a powerful tool to investigate electrochemistry in nanoscale volumes. While most SPM-based studies have focused on reactions at the tip-surface junction, charge and mass conservation requires coupled and intrinsically nonlocal cathodic and anodic processes that can be significantly affected by ambient humidity. Here, we explore the role of water in both cathodic and anodic processes, associated charge transport, and topographic volume changes depending on the polarity of tip bias. The first-order reversal curve current-voltage technique combined with simultaneous detection of the sample topography, referred to as FORC-IVz, was applied to a silver solid ion conductor. We found that the protons generated from water affect silver ionic conduction, silver particle formation and dissolution, and mechanical integrity of the material. This work highlights the dual nature (simultaneously local and nonlocal) of electrochemical SPM studies, which should be considered for comprehensive understanding of nanoscale electrochemistry.

An evaluation of a combined scanning probe and optical microscope for lunar regolith studies

NASA Astrophysics Data System (ADS)

Yang, S.; Pike, W. T.; Staufer, U.; Claus, D.; Rodenburg, J. M.

2011-12-01

The microscopic properties of the lunar regolith such as the shape, the surface texture and the size distribution are required for an understanding of both past surface processes and potential hazards for future human exploration [1]. To reveal the particle morphology at the sub micrometer scale, scanning-probe microscopy (SPM), first used on the 2008 Phoenix mission [1], is a proven approach; however, there are two main challenges for the measurement of lunar particles. Firstly, the SPM tip is liable to move particles during scanning, even when using the lower contact forces of the dynamic-mode imaging. Hence the particles need to be stabilised during imaging. Secondly, typically the AFM tip extends about 10 μm from its cantilever, so larger particles protruding more than this height above their substrates cannot be scanned completely. To immobilize particles and eliminate large particles during SPM scanning, micromachined Si substrates, which have been successfully applied in the Phoenix project for Mars investigation in 2008 [2], have been investigated for lunar analogue material. On these substrates micrometer pits are patterned and serve as traps to enhance the stability of the AFM scanning by grasping the particles. In addition, the diameter of pits can determine the size of dusts to be captured and reduce the adhesion for the larger dust and so eliminate the oversized particles. To extend the imaging range and assist in selecting scan areas for the SPM, we use a type of lensless optical imaging (LOM) which uses ptychographic diffractive imaging [3] to eliminate the restrictions and performance limitations of conventional focusing devices. As a reference, scanning electron microscopy (SEM) which minimizes particle-probe interactions and has the advantage of an extended depth of field, is employed to image the same particle fields at resolutions covering both the SPM and LOM. By comparing the differences and the similarities between SEM and LOM images, the ability of LOM for illuminating the details about the lunar particles sample, is demonstrated. The analysis of SEM and SPM images of the same particles of JSC-LunarA analogue soil reveals the potential of the SPM to obtain reliable microscopic images of lunar dusts including detailed morphology with the help of the micromachined Si substrates. [1] J. D. Carpenter, O. Angerer, M. Durante, D. Linnarson, W. T. Pike, "Life Sciences Investigations for ESA's First Lunar Lander," Earth, Moon, and Planets, Vol.107, pp. 11-23, 2010. [2] S. Vijendran, H.Sykulska, and W. T. Pike, "AFM investigation of Martian soil simulant on micromachined Si substrates," Journal of Microscopy, Vol.227, pp.236-245, Sep. 2007. [3] J.M. Rodenburg, "Ptychography and related diffractive imaging techniques," Advances in Imaging and Electron Physics, Vol.150, pp. 87-184, 2008

Design and Optimization of Nanomaterials for Sensing Applications

NASA Astrophysics Data System (ADS)

Sanderson, Robert Noboru

Nanomaterials, materials with one or more of their dimensions on the nanoscale, have emerged as an important field in the development of next-generation sensing systems. Their high surface-to-volume ratio makes them useful for sensing, but also makes them sensitive to processing defects and inherent material defects. To develop and optimize these systems, it is thus necessary to characterize these defects to understand their origin and how to work around them. Scanning probe microscopy (SPM) techniques like atomic force microscopy (AFM) and scanning tunneling microscopy (STM) are important characterization methods which can measure nanoscale topography and electronic structure. These methods are appealing in nanomaterial systems because they are non-damaging and provide local, high-resolution data, and so are capable of detecting nanoscale features such as single defect sites. There are difficulties, however, in the interpretation of SPM data. For instance, AFM-based methods are prone to experimental artifacts due to long-range interactions, such as capacitive crosstalk in Kelvin probe force microscopy (KPFM), and artifacts due to the finite size of the probe tip, such as incorrect surface tracking at steep topographical features. Mechanical characterization (via force spectroscopy) of nanomaterials with significant nanoscale variations, such as tethered lipid bilayer membranes (tLBMs), is also difficult since variations in the bulk system's mechanical behavior must be distinguished from local fluctuations. Additionally, interpretation of STM data is non-trivial due to local variations in electron density in addition to topographical variations. In this thesis we overcome some limitations of SPM methods by supplementing them with additional surface analytical methods as well as computational methods, and we characterize several nanomaterial systems. Current-carrying vapor-liquid-solid Si nanowires (useful for interdigitated-electrode-based sensors) are characterized using finite-element-method (FEM)-supplemented KPFM to retrieve useful information about processing defects, contact resistance, and the primary charge carriers. Next, a tLBM system's stiffness and the stiffness' dependence on tethering molecule concentration is measured using statistical analysis of thousands of AFM force spectra, demonstrating a biosensor-compatible system with a controllable bulk rigidity. Finally, we utilize surface analytical techniques to inform the development of a novel three-dimensional graphene system for sensing applications.

Control theory for scanning probe microscopy revisited.

PubMed

Stirling, Julian

2014-01-01

We derive a theoretical model for studying SPM feedback in the context of control theory. Previous models presented in the literature that apply standard models for proportional-integral-derivative controllers predict a highly unstable feedback environment. This model uses features specific to the SPM implementation of the proportional-integral controller to give realistic feedback behaviour. As such the stability of SPM feedback for a wide range of feedback gains can be understood. Further consideration of mechanical responses of the SPM system gives insight into the causes of exciting mechanical resonances of the scanner during feedback operation.

Quantification of surface displacements and electromechanical phenomena via dynamic atomic force microscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Balke, Nina; Jesse, Stephen; Yu, Pu

Detection of dynamic surface displacements associated with local changes in material strain provides access to a number of phenomena and material properties. Contact resonance-enhanced methods of atomic force microscopy (AFM) have been shown capable of detecting ~1–3 pm-level surface displacements, an approach used in techniques such as piezoresponse force microscopy, atomic force acoustic microscopy, and ultrasonic force microscopy. Here, based on an analytical model of AFM cantilever vibrations, we demonstrate a guideline to quantify surface displacements with high accuracy by taking into account the cantilever shape at the first resonant contact mode, depending on the tip–sample contact stiffness. The approachmore » has been experimentally verified and further developed for piezoresponse force microscopy (PFM) using well-defined ferroelectric materials. These results open up a way to accurate and precise measurements of surface displacement as well as piezoelectric constants at the pm-scale with nanometer spatial resolution and will allow avoiding erroneous data interpretations and measurement artifacts. Furthermore, this analysis is directly applicable to all cantilever-resonance-based scanning probe microscopy (SPM) techniques.« less

Quantification of surface displacements and electromechanical phenomena via dynamic atomic force microscopy

DOE PAGES

Balke, Nina; Jesse, Stephen; Yu, Pu; ...

2016-09-15

Detection of dynamic surface displacements associated with local changes in material strain provides access to a number of phenomena and material properties. Contact resonance-enhanced methods of atomic force microscopy (AFM) have been shown capable of detecting ~1–3 pm-level surface displacements, an approach used in techniques such as piezoresponse force microscopy, atomic force acoustic microscopy, and ultrasonic force microscopy. Here, based on an analytical model of AFM cantilever vibrations, we demonstrate a guideline to quantify surface displacements with high accuracy by taking into account the cantilever shape at the first resonant contact mode, depending on the tip–sample contact stiffness. The approachmore » has been experimentally verified and further developed for piezoresponse force microscopy (PFM) using well-defined ferroelectric materials. These results open up a way to accurate and precise measurements of surface displacement as well as piezoelectric constants at the pm-scale with nanometer spatial resolution and will allow avoiding erroneous data interpretations and measurement artifacts. Furthermore, this analysis is directly applicable to all cantilever-resonance-based scanning probe microscopy (SPM) techniques.« less

Virtual reality visual feedback for hand-controlled scanning probe microscopy manipulation of single molecules.

PubMed

Leinen, Philipp; Green, Matthew F B; Esat, Taner; Wagner, Christian; Tautz, F Stefan; Temirov, Ruslan

2015-01-01

Controlled manipulation of single molecules is an important step towards the fabrication of single molecule devices and nanoscale molecular machines. Currently, scanning probe microscopy (SPM) is the only technique that facilitates direct imaging and manipulations of nanometer-sized molecular compounds on surfaces. The technique of hand-controlled manipulation (HCM) introduced recently in Beilstein J. Nanotechnol. 2014, 5, 1926-1932 simplifies the identification of successful manipulation protocols in situations when the interaction pattern of the manipulated molecule with its environment is not fully known. Here we present a further technical development that substantially improves the effectiveness of HCM. By adding Oculus Rift virtual reality goggles to our HCM set-up we provide the experimentalist with 3D visual feedback that displays the currently executed trajectory and the position of the SPM tip during manipulation in real time, while simultaneously plotting the experimentally measured frequency shift (Δf) of the non-contact atomic force microscope (NC-AFM) tuning fork sensor as well as the magnitude of the electric current (I) flowing between the tip and the surface. The advantages of the set-up are demonstrated by applying it to the model problem of the extraction of an individual PTCDA molecule from its hydrogen-bonded monolayer grown on Ag(111) surface.

Detailed characterisation of focused ion beam induced lateral damage on silicon carbide samples by electrical scanning probe microscopy and transmission electron microscopy

NASA Astrophysics Data System (ADS)

Stumpf, F.; Abu Quba, A. A.; Singer, P.; Rumler, M.; Cherkashin, N.; Schamm-Chardon, S.; Cours, R.; Rommel, M.

2018-03-01

The lateral damage induced by focused ion beam on silicon carbide was characterized using electrical scanning probe microscopy (SPM), namely, scanning spreading resistance microscopy and conductive atomic force microscopy (c-AFM). It is shown that the damage exceeds the purposely irradiated circles with a radius of 0.5 μm by several micrometres, up to 8 μm for the maximum applied ion dose of 1018 cm-2. Obtained SPM results are critically compared with earlier findings on silicon. For doses above the amorphization threshold, in both cases, three different areas can be distinguished. The purposely irradiated area exhibits resistances smaller than the non-affected substrate. A second region with strongly increasing resistance and a maximum saturation value surrounds it. The third region shows the transition from maximum resistance to the base resistance of the unaffected substrate. It correlates to the transition from amorphized to defect-rich to pristine crystalline substrate. Additionally, conventional transmission electron microscopy (TEM) and annular dark-field STEM were used to complement and explain the SPM results and get a further understanding of the defect spreading underneath the surface. Those measurements also show three different regions that correlate well with the regions observed from electrical SPM. TEM results further allow to explain observed differences in the electrical results for silicon and silicon carbide which are most prominent for ion doses above 3 × 1016 cm-2. Furthermore, the conventional approach to perform current-voltage measurements by c-AFM was critically reviewed and several improvements for measurement and analysis process were suggested that result in more reliable and impactful c-AFM data.

Complete information acquisition in scanning probe microscopy

DOE PAGES

Belianinov, Alex; Kalinin, Sergei V.; Jesse, Stephen

2015-03-13

In the last three decades, scanning probe microscopy (SPM) has emerged as a primary tool for exploring and controlling the nanoworld. A critical part of the SPM measurements is the information transfer from the tip-surface junction to a macroscopic measurement system. This process reduces the many degrees of freedom of a vibrating cantilever to relatively few parameters recorded as images. Similarly, the details of dynamic cantilever response at sub-microsecond time scales of transients, higher-order eigenmodes and harmonics are averaged out by transitioning to millisecond time scale of pixel acquisition. Hence, the amount of information available to the external observer ismore » severely limited, and its selection is biased by the chosen data processing method. Here, we report a fundamentally new approach for SPM imaging based on information theory-type analysis of the data stream from the detector. This approach allows full exploration of complex tip-surface interactions, spatial mapping of multidimensional variability of material s properties and their mutual interactions, and SPM imaging at the information channel capacity limit.« less

Ion irradiation induced surface modification studies of polymers using SPM

NASA Astrophysics Data System (ADS)

Tripathi, A.; Kumar, Amit; Singh, F.; Kabiraj, D.; Avasthi, D. K.; Pivin, J. C.

2005-07-01

Various types of scanning probe microscopy (SPM) techniques: atomic force microscopy (AFM) (contact and tapping in height and amplitude mode), scanning tunnelling microscopy (STM) and conducting atomic force microscopy (C-AFM) are used for studying ion beam induced surface modifications, nanostructure/cluster formation and disintegration in polymers and similar soft carbon based materials. In the present study, the results of studies on four materials, namely, (A) methyltriethoxysilane/phenyltriethoxysilane (MTES/PTES) based gel, (B) triethoxisilane (TH) based gel, (C) highly oriented pyrolytic graphite (HOPG) bulk and (D) fullerene (C60) thin films are discussed. In the case of Si based gels prepared from pre-cursors containing organic groups (MTES/PTES), hillocks are observed at the surface and their size decreases from 70 to 25 nm with increasing fluence, whereas, in the case of a gel with a stoichiometry SiO1.25H1, prepared from TH, an increases in the size of hillocks is observed. Hillocks are also formed at the surface of HOPG irradiated with 120 MeV Au beam at a low fluence, whereas, formation of craters and a re-organisation of surface features is observed at a higher fluence. In the case of C60 films, 120 MeV Au ion irradiation induces the formation of conducting ion tracks, which is attributed to the transformation from insulating C60 to conducting graphite like carbon.

A hybrid analog-digital phase-locked loop for frequency mode non-contact scanning probe microscopy.

PubMed

Mehta, M M; Chandrasekhar, V

2014-01-01

Non-contact scanning probe microscopy (SPM) has developed into a powerful technique to image many different properties of samples. The conventional method involves monitoring the amplitude, phase, or frequency of a cantilever oscillating at or near its resonant frequency as it is scanned across the surface of a sample. For high Q factor cantilevers, monitoring the resonant frequency is the preferred method in order to obtain reasonable scan times. This can be done by using a phase-locked-loop (PLL). PLLs can be obtained as commercial integrated circuits, but these do not have the frequency resolution required for SPM. To increase the resolution, all-digital PLLs requiring sophisticated digital signal processors or field programmable gate arrays have also been implemented. We describe here a hybrid analog/digital PLL where most of the components are implemented using discrete analog integrated circuits, but the frequency resolution is provided by a direct digital synthesis chip controlled by a simple peripheral interface controller (PIC) microcontroller. The PLL has excellent frequency resolution and noise, and can be controlled and read by a computer via a universal serial bus connection.

A hybrid analog-digital phase-locked loop for frequency mode non-contact scanning probe microscopy

NASA Astrophysics Data System (ADS)

Mehta, M. M.; Chandrasekhar, V.

2014-01-01

Non-contact scanning probe microscopy (SPM) has developed into a powerful technique to image many different properties of samples. The conventional method involves monitoring the amplitude, phase, or frequency of a cantilever oscillating at or near its resonant frequency as it is scanned across the surface of a sample. For high Q factor cantilevers, monitoring the resonant frequency is the preferred method in order to obtain reasonable scan times. This can be done by using a phase-locked-loop (PLL). PLLs can be obtained as commercial integrated circuits, but these do not have the frequency resolution required for SPM. To increase the resolution, all-digital PLLs requiring sophisticated digital signal processors or field programmable gate arrays have also been implemented. We describe here a hybrid analog/digital PLL where most of the components are implemented using discrete analog integrated circuits, but the frequency resolution is provided by a direct digital synthesis chip controlled by a simple peripheral interface controller (PIC) microcontroller. The PLL has excellent frequency resolution and noise, and can be controlled and read by a computer via a universal serial bus connection.

Scanning probe microscopy induced surface modifications of the topological insulator Bi2Te3 in different environments

NASA Astrophysics Data System (ADS)

Netsou, Asteriona-Maria; Thupakula, Umamahesh; Debehets, Jolien; Chen, Taishi; Hirsch, Brandon; Volodin, Alexander; Li, Zhe; Song, Fengqi; Seo, Jin Won; De Feyter, Steven; Schouteden, Koen; Van Haesendonck, Chris

2017-08-01

We investigated the topological insulator (TI) Bi2Te3 in four different environments (ambient, ultra-high vacuum (UHV), nitrogen gas and organic solvent environment) using scanning probe microscopy (SPM) techniques. Upon prolonged exposure to ambient conditions and organic solvent environments the cleaved surface of the pristine Bi2Te3 is observed to be strongly modified during SPM measurements, while imaging of freshly cleaved Bi2Te3 in UHV and nitrogen gas shows considerably less changes of the Bi2Te3 surface. We conclude that the reduced surface stability upon exposure to ambient conditions is triggered by adsorption of molecular species from ambient, including H2O, CO2, etc which is verified by Auger electron spectroscopy. Our findings of the drastic impact of exposure to ambient on the Bi2Te3 surface are crucial for further in-depth studies of the intrinsic properties of the TI Bi2Te3 and for potential applications that include room temperature TI based devices operated under ambient conditions.

Synthesis and electroplating of high resolution insulated carbon nanotube scanning probes for imaging in liquid solutions

PubMed Central

Roberts, N.A.; Noh, J.H.; Lassiter, M.G.; Guo, S.; Kalinin, S.V.; Rack, P.D.

2012-01-01

High resolution and isolated scanning probe microscopy (SPM) is in demand for continued development of energy storage and conversion systems involving chemical reactions at the nanoscale as well as an improved understanding of biological systems. Carbon nanotubes (CNTs) have large aspect ratios and, if leveraged properly, can be used to develop high resolution SPM probes. Isolation of SPM probes can be achieved by deposited a dielectric film and selectively etching at the apex of the probe. In this paper the fabrication of a high resolution and isolated SPM tip is demonstrated using electron beam induced etching of a dielectric film deposited onto an SPM tip with an attached CNT at the apex. PMID:22433664

Synthesis and electroplating of high resolution insulated carbon nanotube scanning probes for imaging in liquid solutions.

PubMed

Roberts, N A; Noh, J H; Lassiter, M G; Guo, S; Kalinin, S V; Rack, P D

2012-04-13

High resolution and isolated scanning probe microscopy (SPM) is in demand for continued development of energy storage and conversion systems involving chemical reactions at the nanoscale as well as an improved understanding of biological systems. Carbon nanotubes (CNTs) have large aspect ratios and, if leveraged properly, can be used to develop high resolution SPM probes. Isolation of SPM probes can be achieved by depositing a dielectric film and selectively etching at the apex of the probe. In this paper the fabrication of a high resolution and isolated SPM tip is demonstrated using electron beam induced etching of a dielectric film deposited onto an SPM tip with an attached CNT at the apex.

Study of the properties of new SPM detectors

NASA Astrophysics Data System (ADS)

Stewart, A. G.; Greene-O'Sullivan, E.; Herbert, D. J.; Saveliev, V.; Quinlan, F.; Wall, L.; Hughes, P. J.; Mathewson, A.; Jackson, J. C.

2006-02-01

The operation and performance of multi-pixel, Geiger-mode APD structures referred to as Silicon Photomultiplier (SPM) are reported. The SPM is a solid state device that has emerged over the last decade as a promising alternative to vacuum PMTs. This is due to their comparable performance in addition to their lower bias operation and power consumption, insensitivity to magnetic fields and ambient light, smaller size and ruggedness. Applications for these detectors are numerous and include life sciences, nuclear medicine, particle physics, microscopy and general instrumentation. With SPM devices, many geometrical and device parameters can be adjusted to optimize their performance for a particular application. In this paper, Monte Carlo simulations and experimental results for 1mm2 SPM structures are reported. In addition, trade-offs involved in optimizing the SPM in terms of the number and size of pixels for a given light intensity, and its affect on the dynamic range are discussed.

DNA condensation by chiral alpha-methylated polyamine analogues and protection of cellular DNA from oxidative damage.

PubMed

Nayvelt, Irina; Hyvönen, Mervi T; Alhonen, Leena; Pandya, Ipsit; Thomas, Thresia; Khomutov, Alex R; Vepsäläinen, Jouko; Patel, Rajesh; Keinänen, Tuomo A; Thomas, T J

2010-01-11

Polyamines are essential molecules supporting the structure, conformation, and function of nucleic acids and proteins. We studied stereoisomers of alpha,alpha'-dimethylated spermine [(R,R)-Me(2)Spm, (S,S)-Me(2)Spm, (R,S)-Me(2)Spm] for their ability to provoke DNA condensation and protect DNA from damage. (R,R)- and (R,S)-Me(2)Spm displayed more efficient condensing ability than spermine, with significantly lower EC(50) (concentration for 50% compaction) values (p < or = 0.01). However, spermine exerted slightly more duplex stabilization than Me(2)Spm. Condensation resulted in nanoparticles with hydrodynamic radii between 39.6 and 48.4 nm, and electron microscopy showed the presence of toroids and spheroids. Natural polyamines and stereoisomers of Me(2)Spm protected DNA against DNase digestion and oxidative stress in vitro and against etoposide and oxidative stress in DU145 cells but afforded little protection against UV-C irradiation. Our findings indicate that Me(2)Spm stereoisomers are efficient DNA packaging agents with potential applications in gene delivery. Our study also reveals stereospecificity in DNA interaction and protection against cellular stress.

Microfabrication of Silicon/Ceramic Hybrid Cantilever for Scanning Probe Microscope and Sensor Applications

NASA Astrophysics Data System (ADS)

Wakayama, Takayuki; Kobayashi, Toshinari; Iwata, Nobuya; Tanifuji, Nozomi; Matsuda, Yasuaki; Yamada, Syoji

2003-12-01

We present here new cantilevers for scanning probe microscopy (SPM) and sensor applications, which consist of silicon cantilever beam and ceramic pedestal. Silicon is only used to make cantilever beams and tips. Precision-machinery-made ceramics replaces silicon pedestal part. The ceramics was recently developed by Sumikin Ceramics and Quarts Co., Ltd. and can be machined precisely with end mill cutting. Many silicon beams are fabricated at once from a wafer using batch fabrication method. Therefore, SPM probes can be fabricated in high productivity and in low cost. These beams are transferred with transfer technique and are bonded on the ceramic pedestal with epoxy glue. We demonstrate here atomic force microscope (AFM) and gas sensor applications of the hybrid structure. In a gas sensor application, the ends of the cantilever are selectively modified with zeolite crystals as a sensitive layer. The bonding strength is enough for each application.

Real Space Imaging of the Microscopic Origins of the Ultrahigh Dielectric Constant in Polycrystalline CaCu 3Ti 4O 12

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kalinin, Sergei V; Shin, Junsoo; Veith, Gabriel M

2005-01-01

The origins of an ultrahigh dielectric constant in polycrystalline CaCu{sub 3}Ti{sub 4}O{sub 12} (CCTO) were studied using the combination of impedance spectroscopy, electron microscopy, and scanning probe microscopy (SPM). Impedance spectra indicate that the transport properties in the 0.1 Hz-1 MHz frequency range are dominated by a single parallel resistive-capacitive (RC) element with a characteristic relaxation frequency of 16 Hz. dc potential distributions measurements by SPM illustrate that significant potential drops occur at the grain boundaries, which thus can be unambiguously identified as the dominant RC element. High frequency ac amplitude and phase distributions illustrate very weak grain boundary contrastmore » in SPM, indicative of strong capacitive coupling across the interfaces. These results demonstrate that the ultrahigh dielectric constant reported for polycrystalline CCTO materials is related to grain-boundary behavior.« less

Teaching Plasmonics, Scanning Probe Microscopy and Other Useful Experiments at the Upper Level

NASA Astrophysics Data System (ADS)

Sanchez, Erik

2012-10-01

It is important to teach students concepts and experimental skills relating to modern research being performed today. Experiments that help educate students about the latest research helps them get jobs and into the doors at many great academic institutions. PSU's Advanced Experimental Class for physics undergraduates offers many novel experiments to help the students accomplish this task. Labs involving Plasmonics, thin film deposition, scanning probe microscopy (SPM) and more will be discussed. In addition, a new NSF funded project involving the building of a Do-It-Yourself (DIY) SPM will be discussed.

Statistical process management: An essential element of quality improvement

NASA Astrophysics Data System (ADS)

Buckner, M. R.

Successful quality improvement requires a balanced program involving the three elements that control quality: organization, people and technology. The focus of the SPC/SPM User's Group is to advance the technology component of Total Quality by networking within the Group and by providing an outreach within Westinghouse to foster the appropriate use of statistic techniques to achieve Total Quality. SPM encompasses the disciplines by which a process is measured against its intrinsic design capability, in the face of measurement noise and other obscuring variability. SPM tools facilitate decisions about the process that generated the data. SPM deals typically with manufacturing processes, but with some flexibility of definition and technique it accommodates many administrative processes as well. The techniques of SPM are those of Statistical Process Control, Statistical Quality Control, Measurement Control, and Experimental Design. In addition, techniques such as job and task analysis, and concurrent engineering are important elements of systematic planning and analysis that are needed early in the design process to ensure success. The SPC/SPM User's Group is endeavoring to achieve its objectives by sharing successes that have occurred within the member's own Westinghouse department as well as within other US and foreign industry. In addition, failures are reviewed to establish lessons learned in order to improve future applications. In broader terms, the Group is interested in making SPM the accepted way of doing business within Westinghouse.

Image-based overlay measurement using subsurface ultrasonic resonance force microscopy

NASA Astrophysics Data System (ADS)

Tamer, M. S.; van der Lans, M. J.; Sadeghian, H.

2018-03-01

Image Based Overlay (IBO) measurement is one of the most common techniques used in Integrated Circuit (IC) manufacturing to extract the overlay error values. The overlay error is measured using dedicated overlay targets which are optimized to increase the accuracy and the resolution, but these features are much larger than the IC feature size. IBO measurements are realized on the dedicated targets instead of product features, because the current overlay metrology solutions, mainly based on optics, cannot provide sufficient resolution on product features. However, considering the fact that the overlay error tolerance is approaching 2 nm, the overlay error measurement on product features becomes a need for the industry. For sub-nanometer resolution metrology, Scanning Probe Microscopy (SPM) is widely used, though at the cost of very low throughput. The semiconductor industry is interested in non-destructive imaging of buried structures under one or more layers for the application of overlay and wafer alignment, specifically through optically opaque media. Recently an SPM technique has been developed for imaging subsurface features which can be potentially considered as a solution for overlay metrology. In this paper we present the use of Subsurface Ultrasonic Resonance Force Microscopy (SSURFM) used for IBO measurement. We used SSURFM for imaging the most commonly used overlay targets on a silicon substrate and photoresist. As a proof of concept we have imaged surface and subsurface structures simultaneously. The surface and subsurface features of the overlay targets are fabricated with programmed overlay errors of +/-40 nm, +/-20 nm, and 0 nm. The top layer thickness changes between 30 nm and 80 nm. Using SSURFM the surface and subsurface features were successfully imaged and the overlay errors were extracted, via a rudimentary image processing algorithm. The measurement results are in agreement with the nominal values of the programmed overlay errors.

Availability of feature-oriented scanning probe microscopy for remote-controlled measurements on board a space laboratory or planet exploration Rover.

PubMed

Lapshin, Rostislav V

2009-06-01

Prospects for a feature-oriented scanning (FOS) approach to investigations of sample surfaces, at the micrometer and nanometer scales, with the use of scanning probe microscopy under space laboratory or planet exploration rover conditions, are examined. The problems discussed include decreasing sensitivity of the onboard scanning probe microscope (SPM) to temperature variations, providing autonomous operation, implementing the capabilities for remote control, self-checking, self-adjustment, and self-calibration. A number of topical problems of SPM measurements in outer space or on board a planet exploration rover may be solved via the application of recently proposed FOS methods.

SPM Investigation of Thiolated Gold Nanoparticle Patterns Deposited on Different Self-Assembled Substrates

NASA Astrophysics Data System (ADS)

Sbrana, F.; Parodi, M. T.; Ricci, D.; Di Zitti, E.

We present the results of a Scanning Probe Microscopy (SPM) investigation of ordered nanosized metallo-organic structures. Our aim is to investigate the organization and stability of thiolated gold nanoparticles in a compact pattern when deposited onto gold substrates functionalized with self-assembled monolayers made from two molecules that differ essentially in their terminating group: 1,4-benzenedimethanethiol and 4-methylbenzylthiol.

Bipolar charge storage characteristics in copper and cobalt co-doped zinc oxide (ZnO) thin film.

PubMed

Kumar, Amit; Herng, Tun Seng; Zeng, Kaiyang; Ding, Jun

2012-10-24

The bipolar charge phenomenon in Cu and Co co-doped zinc oxide (ZnO) film samples has been studied using scanning probe microscopy (SPM) techniques. Those ZnO samples are made using a pulsed laser deposition (PLD) technique. It is found that the addition of Cu and Co dopants suppresses the electron density in ZnO and causes a significant change in the work function (Fermi level) value of the ZnO film; this results in the ohmic nature of the contact between the electrode (probe tip) and codoped sample, whereas this contact exhibits a Schottky nature in the undoped and single-element-doped samples. These results are verified by Kelvin probe force microscopy (KPFM) and ultraviolet photoelectron spectroscopy (UPS) measurements. It is also found that the co-doping (Cu and Co) can stabilize the bipolar charge, whereas Cu doping only stabilizes the positive charge in ZnO thin films.

Preface to Special Topic: Piezoresponse Force Microscopy

DOE PAGES

Balke, Nina; Bassiri-Gharb, Nazanin; Lichtensteiger, Céline

2015-08-19

Almost two decades beyond the inception of piezoresponse force microscopy (PFM) and the seminal papers by G€uthner and Dransfeld1 and Gruverman et al., the technique has become the prevailing approach for nanoscale functional characterization of polar materials and has been extended to the probing of other electromechanical effects through the advent of electrochemical strain microscopy (ESM). This focus issue celebrates some of the recent advances in the field and offers a wider outlook of polar materials and their overall characterization. In this paper, we cover topics that include discussions of the properties of traditional ferroelectrics, such as lead zirconate titanatemore » (PZT) and lithium niobate, relaxorferroelectrics, as well as more “exotic” ferroelectric oxides such as hafnia, ferroelectric biological matter, and multiferroic materials. Technique-oriented contributions include papers on the coupling of PFM with other characterization methods such as x-ray diffraction (XRD) and superconducting quantum interface device (SQUID), in addition to considerations on the open questions on the electromechanical response in biased scanning probe microscopy (SPM) techniques, including the effects of the laser spot placement on the readout cantilever displacement, the influence of the tip on the creation of the domain shapes, and the impact of ionic and electronic dynamics on the observed nanoscale hysteretic phenomena.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Balke, Nina; Bassiri-Gharb, Nazanin; Lichtensteiger, Céline

Almost two decades beyond the inception of piezoresponse force microscopy (PFM) and the seminal papers by G€uthner and Dransfeld1 and Gruverman et al., the technique has become the prevailing approach for nanoscale functional characterization of polar materials and has been extended to the probing of other electromechanical effects through the advent of electrochemical strain microscopy (ESM). This focus issue celebrates some of the recent advances in the field and offers a wider outlook of polar materials and their overall characterization. In this paper, we cover topics that include discussions of the properties of traditional ferroelectrics, such as lead zirconate titanatemore » (PZT) and lithium niobate, relaxorferroelectrics, as well as more “exotic” ferroelectric oxides such as hafnia, ferroelectric biological matter, and multiferroic materials. Technique-oriented contributions include papers on the coupling of PFM with other characterization methods such as x-ray diffraction (XRD) and superconducting quantum interface device (SQUID), in addition to considerations on the open questions on the electromechanical response in biased scanning probe microscopy (SPM) techniques, including the effects of the laser spot placement on the readout cantilever displacement, the influence of the tip on the creation of the domain shapes, and the impact of ionic and electronic dynamics on the observed nanoscale hysteretic phenomena.« less

A versatile technique for fabrication of SiC SPM probes

NASA Astrophysics Data System (ADS)

Therrien, Joel; Schmidt, Daniel; Barrot, Sheetal; Patel, Bhavin

2008-03-01

To date SPM probes have largely been fabricated via methods borrowed from the semiconductor industry for fabricating Micro Electro Mechanical Systems. Although these techniques have enabled SPM to see widespread use, the processes put significant limitations on what structures can be made. We report our progress on fabricating SPM cantilevers composed of Silicon Carbide using polymer molding techniques. A pre-ceramic polymer is molded into the desired probe shape and then converted to SiC via pyrolisys. We will also report on progress in using photo-sterolithography for fabrication of even more complex geometries. In addition to opening up a much larger set of probe structures, the use of SiC leads to improved wear resistance of the resulting probes. Among the potential applications, this method enables the fabrication of low spring constant, high resonant frequency cantilevers via cross sectional geometries not accessible to standard fabrication techniques. Such probes are required for high speed tapping and non-contact imaging.

Nanoscale patterning of Si surface using SPM scratching

NASA Astrophysics Data System (ADS)

Ogino, T.; Nishimura, S.; Shirakashi, J.

2008-03-01

Nanolithography of Si surface using scanning probe microscopy (SPM) scratching with a diamond-coated tip was systematically investigated at a low force regime below 9 μN. The groove patterns with controlled width and depth could be achieved by adjusting the applied force, scan direction and the number of scan cycles. There was no effect of scan speed on the groove size. The minimum groove width of 10 nm was obtained on Si surfaces. Furthermore, more complex nanostructures such as line and space patterns of 30 nm pith and dot arrays of 2.6×1010 cm-2 density were realized. SPM scratching with a diamond-coated tip allows nanoscale patterning of Si surfaces to be performed simply.

Characterization of LiMn 2O 4 cathodes by electrochemical strain microscopy

DOE PAGES

Alikin, D. O.; Ievlev, A. V.; Luchkin, S. Yu.; ...

2016-03-15

Electrochemical strain microscopy (ESM) is a scanning probe microscopy(SPM) method in which the local electrodiffusion is probed via application of AC voltage to the SPM tip and registration of resulting electrochemical strain. In this study, we implemented ESM to measure local strain in bulk LiMn 2O 4 cathodes of a commercial Li-battery in different states of charge to investigate distribution of Li-ion mobility and concentration. Ramped AC ESM imaging and voltage spectroscopy were used to find the most reliable regime of measurements allowing separating and diminishing different contributions to ESM. This is not a trivial task due to complex geometrymore » of the sample and various obstacles resulting in less predictable contributions of different origins into ESM response: electrostatic tip–surface interactions, charge injection, electrostriction, and flexoelectricity. Finally, understanding and control of these contributions is an important step towards quantitative interpretation of ESM data.« less

General Mode Scanning Probe Microscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Somnath, Suhas; Jesse, Stephen

A critical part of SPM measurements is the information transfer from the probe-sample junction to the measurement system. Current information transfer methods heavily compress the information-rich data stream by averaging the data over a time interval, or via heterodyne detection approaches such as lock-in amplifiers and phase-locked loops. As a consequence, highly valuable information at the sub-microsecond time scales or information from frequencies outside the measurement band is lost. We have developed a fundamentally new approach called General Mode (G-mode), where we can capture the complete information stream from the detectors in the microscope. The availability of the complete informationmore » allows the microscope operator to analyze the data via information-theory analysis or comprehensive physical models. Furthermore, the complete data stream enables advanced data-driven filtering algorithms, multi-resolution imaging, ultrafast spectroscropic imaging, spatial mapping of multidimensional variability in material properties, etc. Though we applied this approach to scanning probe microscopy, the general philosophy of G-mode can be applied to many other modes of microscopy. G-mode data is captured by completely custom software written in LabVIEW and Matlab. The software generates the waveforms to electrically, thermally, or mechanically excite the SPM probe. It handles real-time communications with the microscope software for operations such as moving the SPM probe position and also controls other instrumentation hardware. The software also controls multiple variants of high-speed data acquisition cards to excite the SPM probe with the excitation waveform and simultaneously measure multiple channels of information from the microscope detectors at sampling rates of 1-100 MHz. The software also saves the raw data to the computer and allows the microscope operator to visualize processed or filtered data during the experiment. The software performs all these features while offering a user-friendly interface.« less

An Undergraduate Nanotechnology Engineering Laboratory Course on Atomic Force Microscopy

ERIC Educational Resources Information Center

Russo, D.; Fagan, R. D.; Hesjedal, T.

2011-01-01

The University of Waterloo, Waterloo, ON, Canada, is home to North America's first undergraduate program in nanotechnology. As part of the Nanotechnology Engineering degree program, a scanning probe microscopy (SPM)-based laboratory has been developed for students in their fourth year. The one-term laboratory course "Nanoprobing and…

PREDICTING CHEMICAL REACTIVITY OF HUMIC SUBSTANCES FOR MINERALS AND XENOBIOTICS: USE OF COMPUTATIONAL CHEMISTRY, SCANNING PROBE MICROSCOPY AND VIRTUAL REALITY

EPA Science Inventory

In this chapter we review the literature on scanning probe microscopy (SPM), virtual reality (VR), and computational chemistry and our earlier work dealing with modeling lignin, lignin-carbohydrate complexes (LCC), humic substances (HSs) and non-bonded organo-mineral interactions...

Data mining graphene: Correlative analysis of structure and electronic degrees of freedom in graphenic monolayers with defects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ziatdinov, Maxim A.; Fujii, Shintaro; Kiguchi, Manabu

The link between changes in the material crystal structure and its mechanical, electronic, magnetic, and optical functionalities known as the structure-property relationship is the cornerstone of the contemporary materials science research. The recent advances in scanning transmission electron and scanning probe microscopies (STEM and SPM) have opened an unprecedented path towards examining the materials structure property relationships on the single-impurity and atomic-configuration levels. Lacking, however, are the statistics-based approaches for cross-correlation of structure and property variables obtained in different information channels of the STEM and SPM experiments. Here we have designed an approach based on a combination of sliding windowmore » Fast Fourier Transform, Pearson correlation matrix, linear and kernel canonical correlation, to study a relationship between lattice distortions and electron scattering from the SPM data on graphene with defects. Our analysis revealed that the strength of coupling to strain is altered between different scattering channels which can explain coexistence of several quasiparticle interference patterns in the nanoscale regions of interest. In addition, the application of the kernel functions allowed us extracting a non-linear component of the relationship between the lattice strain and scattering intensity in graphene. Lastly, the outlined approach can be further utilized to analyzing correlations in various multi-modal imaging techniques where the information of interest is spatially distributed and has usually a complex multidimensional nature.« less

Data mining graphene: Correlative analysis of structure and electronic degrees of freedom in graphenic monolayers with defects

DOE PAGES

Ziatdinov, Maxim A.; Fujii, Shintaro; Kiguchi, Manabu; ...

2016-11-09

The link between changes in the material crystal structure and its mechanical, electronic, magnetic, and optical functionalities known as the structure-property relationship is the cornerstone of the contemporary materials science research. The recent advances in scanning transmission electron and scanning probe microscopies (STEM and SPM) have opened an unprecedented path towards examining the materials structure property relationships on the single-impurity and atomic-configuration levels. Lacking, however, are the statistics-based approaches for cross-correlation of structure and property variables obtained in different information channels of the STEM and SPM experiments. Here we have designed an approach based on a combination of sliding windowmore » Fast Fourier Transform, Pearson correlation matrix, linear and kernel canonical correlation, to study a relationship between lattice distortions and electron scattering from the SPM data on graphene with defects. Our analysis revealed that the strength of coupling to strain is altered between different scattering channels which can explain coexistence of several quasiparticle interference patterns in the nanoscale regions of interest. In addition, the application of the kernel functions allowed us extracting a non-linear component of the relationship between the lattice strain and scattering intensity in graphene. Lastly, the outlined approach can be further utilized to analyzing correlations in various multi-modal imaging techniques where the information of interest is spatially distributed and has usually a complex multidimensional nature.« less

SPM for functional identification of individual biomolecules

NASA Astrophysics Data System (ADS)

Ros, Robert; Schwesinger, Falk; Padeste, Celestino; Plueckthun, Andreas; Anselmetti, Dario; Guentherodt, Hans-Joachim; Tiefenauer, Louis

1999-06-01

The identification of specific binding molecules is of increasing interest in the context of drug development based on combinatorial libraries. Scanning Probe Microscopy (SPM) is the method of choice to image and probe individual biomolecules on a surface. Functional identification of biomolecules is a first step towards screening on a single molecule level. As a model system we use recombinant single- chain Fv fragment (scFv) antibody molecules directed against the antigen fluorescein. The scFv's are covalently immobilized on a flat gold surface via the C-terminal cysteine, resulting in a high accessibility of the binding site. The antigen is immobilized covalently via a long hydrophilic spacer to the silicon nitride SPM-tip. This arrangement allows a direct measurement of binding forces. Thus, closely related antibody molecules differing in only one amino acid at their binding site could be distinguished. A novel SPM-software has been developed which combines imaging, force spectroscopic modes, and online analysis. This is a major prerequisite for future screening methods.

High-resolution high-sensitivity elemental imaging by secondary ion mass spectrometry: from traditional 2D and 3D imaging to correlative microscopy

NASA Astrophysics Data System (ADS)

Wirtz, T.; Philipp, P.; Audinot, J.-N.; Dowsett, D.; Eswara, S.

2015-10-01

Secondary ion mass spectrometry (SIMS) constitutes an extremely sensitive technique for imaging surfaces in 2D and 3D. Apart from its excellent sensitivity and high lateral resolution (50 nm on state-of-the-art SIMS instruments), advantages of SIMS include high dynamic range and the ability to differentiate between isotopes. This paper first reviews the underlying principles of SIMS as well as the performance and applications of 2D and 3D SIMS elemental imaging. The prospects for further improving the capabilities of SIMS imaging are discussed. The lateral resolution in SIMS imaging when using the microprobe mode is limited by (i) the ion probe size, which is dependent on the brightness of the primary ion source, the quality of the optics of the primary ion column and the electric fields in the near sample region used to extract secondary ions; (ii) the sensitivity of the analysis as a reasonable secondary ion signal, which must be detected from very tiny voxel sizes and thus from a very limited number of sputtered atoms; and (iii) the physical dimensions of the collision cascade determining the origin of the sputtered ions with respect to the impact site of the incident primary ion probe. One interesting prospect is the use of SIMS-based correlative microscopy. In this approach SIMS is combined with various high-resolution microscopy techniques, so that elemental/chemical information at the highest sensitivity can be obtained with SIMS, while excellent spatial resolution is provided by overlaying the SIMS images with high-resolution images obtained by these microscopy techniques. Examples of this approach are given by presenting in situ combinations of SIMS with transmission electron microscopy (TEM), helium ion microscopy (HIM) and scanning probe microscopy (SPM).

Superparamagnetic nano-immunobeads toward food safety insurance

NASA Astrophysics Data System (ADS)

Liu, Xuefeng; Zhang, Lei; Zeng, Jing; Gao, Yan; Tang, Zhiyong

2013-07-01

In this work, superparamagnetic nano-immunobeads (SPM-NIBs) based on conjugation of superparamagnetic Fe3O4 nanoparticles with specific antibodies have been developed toward food safety insurance. The resultant SPM-NIBs exhibits excellent colloidal stability and reversible magnetic response. Vibrio parahaemolyticus, which is a main foodborne pathogenes from contaminated seafood, can be separated specifically and efficiently by the resultant SPM-NIBs. The results of bacteria separation demonstrate that the SPM-NIBs have a higher specific activity and sensitivity toward V. parahaemolyticus. About 80 % of V. parahaemolyticus cells can be captured when the concentration of the broth reaches 103 CFU/mL. Thus, the SPM-NIBs can effectively enhance the efficiency for target bacteria inspections by shortening the period of culture time. This work holds the promise of development of general technique to prepare effective SPM-NIBs toward food safety inspections and other bio-related applications for target analyte separation and collection.

[Substances transport in an underground river of typical karst watershed during storm events].

PubMed

Yang, Ping-Heng; Kuang, Ying-Lun; Yuan, Wen-Hao; Jia, Peng; He, Qiu-Fang; Lin, Yu-Shi

2009-11-01

Hydrologic process, turbidity, suspended particles matters (SPM), major cations and TOC concentrations during two storm events in late April 2008 were monitored at Jiangjia Spring which is the outlet of Qingmu Guan underground river system. Scanning electron microscopy (SEM) and energy disperse spectroscopy (EDS) analyses of SPM were also performed in order to investigate the transport characteristics of substances, such as SPM, turbidity and major cations in the underground river of typical karst watershed. The results show that at a single and well-developed karst conduit of Jiangjia Spring, discharge, turbidity, and concentrations of SPM, major cations and TOC respond promptly to the rainfall. The carbonate-derived cations including Ca2+, Mg2+ and Sr2+ are subject to dilution effect during the rising limb of discharge. The elevation in turbidity and SPM concentration is a result of the gradual increase of allochthonous substances (soil) flux input from the surface. Al3+, Fe, Mn, Ba2+ and TOC are concomitant substances of SPM. And their concentrations are ascending with turbid rise. The flux of SPM in diameter > 0.45 microm in the underground river is about 9.7 tons during the events. The bad water quality suggests us that the spring water is unfit to drink without purification during the period of rising and recession time of discharge at Jiangjia Spring. Thus, soil erosion and nutrient losing not only strongly destroy the fragile karst ecological environment, but also lead to non-point source pollution, and seriously threaten the drinking water safety of locals.

Imaging electron motion in graphene

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhandari, Sagar; Westervelt, Robert M.

A cooled scanning probe microscope (SPM) is an ideal tool to image electronic motion in graphene: the SPM tip acts as a scanning gate, which interacts with the electron gas below. We introduce the technique using our group's previous work on imaging electron flow from a quantum point contact in a GaAs 2DEG and tuning an InAs quantum dot in an InAs/InP nanowire. Carriers in graphene have very different characteristics: electrons and holes travel at a constant speed with no bandgap, and they pass through potential barriers via Klein tunneling. In this paper, we review the extension of SPM imagingmore » techniques to graphene. We image the cyclotron orbits passing between two narrow contacts in a single-atomic-layer graphene device in a perpendicular magnetic field. Magnetic focusing produces a peak in transmission between the contacts when the cyclotron diameter is equal to the contact spacing. The charged SPM tip deflects electrons passing from one contact to the other, changing the transmission when it interrupts the flow. By displaying the change in transmission as the tip is raster scanned above the sample, an image of flow is obtained. In addition, we have developed a complementary technique to image electronic charge using a cooled scanning capacitance microscope (SCM) that uses a sensitive charge preamplifier near the SPM tip to achieve a charge noise level 0.13 e Hz -1/2 with high spatial resolution 100 nm. The cooled SPM and SCM can be used to probe the motion of electrons on the nanoscale in graphene devices.« less

Imaging electron motion in graphene

DOE PAGES

Bhandari, Sagar; Westervelt, Robert M.

2017-01-05

A cooled scanning probe microscope (SPM) is an ideal tool to image electronic motion in graphene: the SPM tip acts as a scanning gate, which interacts with the electron gas below. We introduce the technique using our group's previous work on imaging electron flow from a quantum point contact in a GaAs 2DEG and tuning an InAs quantum dot in an InAs/InP nanowire. Carriers in graphene have very different characteristics: electrons and holes travel at a constant speed with no bandgap, and they pass through potential barriers via Klein tunneling. In this paper, we review the extension of SPM imagingmore » techniques to graphene. We image the cyclotron orbits passing between two narrow contacts in a single-atomic-layer graphene device in a perpendicular magnetic field. Magnetic focusing produces a peak in transmission between the contacts when the cyclotron diameter is equal to the contact spacing. The charged SPM tip deflects electrons passing from one contact to the other, changing the transmission when it interrupts the flow. By displaying the change in transmission as the tip is raster scanned above the sample, an image of flow is obtained. In addition, we have developed a complementary technique to image electronic charge using a cooled scanning capacitance microscope (SCM) that uses a sensitive charge preamplifier near the SPM tip to achieve a charge noise level 0.13 e Hz -1/2 with high spatial resolution 100 nm. The cooled SPM and SCM can be used to probe the motion of electrons on the nanoscale in graphene devices.« less

Methods for determining and processing 3D errors and uncertainties for AFM data analysis

NASA Astrophysics Data System (ADS)

Klapetek, P.; Nečas, D.; Campbellová, A.; Yacoot, A.; Koenders, L.

2011-02-01

This paper describes the processing of three-dimensional (3D) scanning probe microscopy (SPM) data. It is shown that 3D volumetric calibration error and uncertainty data can be acquired for both metrological atomic force microscope systems and commercial SPMs. These data can be used within nearly all the standard SPM data processing algorithms to determine local values of uncertainty of the scanning system. If the error function of the scanning system is determined for the whole measurement volume of an SPM, it can be converted to yield local dimensional uncertainty values that can in turn be used for evaluation of uncertainties related to the acquired data and for further data processing applications (e.g. area, ACF, roughness) within direct or statistical measurements. These have been implemented in the software package Gwyddion.

High speed operation of permanent magnet machines

NASA Astrophysics Data System (ADS)

El-Refaie, Ayman M.

This work proposes methods to extend the high-speed operating capabilities of both the interior PM (IPM) and surface PM (SPM) machines. For interior PM machines, this research has developed and presented the first thorough analysis of how a new bi-state magnetic material can be usefully applied to the design of IPM machines. Key elements of this contribution include identifying how the unique properties of the bi-state magnetic material can be applied most effectively in the rotor design of an IPM machine by "unmagnetizing" the magnet cavity center posts rather than the outer bridges. The importance of elevated rotor speed in making the best use of the bi-state magnetic material while recognizing its limitations has been identified. For surface PM machines, this research has provided, for the first time, a clear explanation of how fractional-slot concentrated windings can be applied to SPM machines in order to achieve the necessary conditions for optimal flux weakening. A closed-form analytical procedure for analyzing SPM machines designed with concentrated windings has been developed. Guidelines for designing SPM machines using concentrated windings in order to achieve optimum flux weakening are provided. Analytical and numerical finite element analysis (FEA) results have provided promising evidence of the scalability of the concentrated winding technique with respect to the number of poles, machine aspect ratio, and output power rating. Useful comparisons between the predicted performance characteristics of SPM machines equipped with concentrated windings and both SPM and IPM machines designed with distributed windings are included. Analytical techniques have been used to evaluate the impact of the high pole number on various converter performance metrics. Both analytical techniques and FEA have been used for evaluating the eddy-current losses in the surface magnets due to the stator winding subharmonics. Techniques for reducing these losses have been investigated. A 6kW, 36slot/30pole prototype SPM machine has been designed and built. Experimental measurements have been used to verify the analytical and FEA results. These test results have demonstrated that wide constant-power speed range can be achieved. Other important machine features such as the near-sinusoidal back-emf, high efficiency, and low cogging torque have also been demonstrated.

Standardization in dimensional nanometrology: development of a calibration guideline for Scanning Probe Microscopy

NASA Astrophysics Data System (ADS)

Dziomba, Thorsten; Koenders, Ludger; Wilkening, Günter

2005-10-01

The continuing miniaturization in many technologies - among them the optical systems - demands high-resolution measurements with uncertainties in the nanometre-range or even well below. A brief introduction of measurement methods used at the micro- & nanometre scale is therefore given as introduction. While a wide range of these methods are well established for the determination of various physical properties down to the nanometric scale, it is Scanning Probe Microscopy (SPM) that provides a unique direct access to topographic surface features in the size range from atomic diameters to some ten or hundred micrometres. With the increasing use of SPMs as quantitative measurement instruments, the demand for standardized calibration routines also for this type of instruments rises. However, except for a few specially designed set-ups mainly at National Metrology Institutes (e. g. PTB in Germany), measurements made with SPMs usually lack traceability to the metre definition. A number of physical transfer standards have therefore been developed and are already available commercially. While detailed knowledge of the standards' properties is a prerequisite for their practical applicability, the calibration procedure itself deserves careful consideration as well. As there is, up to now, no generally accepted concept how to perform SPM calibrations, guidelines are now being developed on various national and international levels, e. g. VDI/VDE-GMA in Germany and ISO. This papers discusses the draft of an SPM calibration guideline by focusing on several critical practical aspects of SPM calibration. The paper intends to invite the readers to take active part in guideline discussions.

Two Simple Classroom Demonstrations for Scanning Probe Microscopy Based on a Macroscopic Analogy

ERIC Educational Resources Information Center

Hajkova, Zdenka; Fejfar, Antonin; Smejkal, Petr

2013-01-01

This article describes two simple classroom demonstrations that illustrate the principles of scanning probe microscopy (SPM) based on a macroscopic analogy. The analogy features the bumps in an egg carton to represent the atoms on a chemical surface and a probe that can be represented by a dwarf statue (illustrating an origin of the prefix…

Localization of puroindoline-a and lipids in bread dough using confocal scanning laser microscopy.

PubMed

Dubreil, Laurence; Biswas, Samares C; Marion, Didier

2002-10-09

Puroindolines are lipid-binding proteins from wheat flour that play a significant role in bread crumb texture. The localization of wheat flour lipids and puroindoline-a (PIN-a) in bread dough was studied by confocal scanning laser microscopy (CSLM). Wheat lipids were located around gas cells (GC) and embedded within the protein-starch matrix (SPM) of the dough. PIN-a was mainly located in the matrix of dough, where it was associated with lipids. In contrast, in defatted dough, PIN-a was found around GC. Addition of puroindolines in bread dough induced a defatting of the gas bubble surface and a decrease of the lipid vesicles and/or droplet size embedded within the SPM. Therefore, puroindolines control the lipid partitioning within the different phases of dough, a phenomenon that should have important consequence on the gas bubble expansion and GC formation in the further stages (fermentation, baking) of the bread-making process.

Advanced dynamic statistical parametric mapping with MEG in localizing epileptogenicity of the bottom of sulcus dysplasia.

PubMed

Nakajima, Midori; Wong, Simeon; Widjaja, Elysa; Baba, Shiro; Okanishi, Tohru; Takada, Lynne; Sato, Yosuke; Iwata, Hiroki; Sogabe, Maya; Morooka, Hikaru; Whitney, Robyn; Ueda, Yuki; Ito, Tomoshiro; Yagyu, Kazuyori; Ochi, Ayako; Carter Snead, O; Rutka, James T; Drake, James M; Doesburg, Sam; Takeuchi, Fumiya; Shiraishi, Hideaki; Otsubo, Hiroshi

2018-06-01

To investigate whether advanced dynamic statistical parametric mapping (AdSPM) using magnetoencephalography (MEG) can better localize focal cortical dysplasia at bottom of sulcus (FCDB). We analyzed 15 children with diagnosis of FCDB in surgical specimen and 3 T MRI by using MEG. Using AdSPM, we analyzed a ±50 ms epoch relative to each single moving dipole (SMD) and applied summation technique to estimate the source activity. The most active area in AdSPM was defined as the location of AdSPM spike source. We compared spatial congruence between MRI-visible FCDB and (1) dipole cluster in SMD method; and (2) AdSPM spike source. AdSPM localized FCDB in 12 (80%) of 15 children whereas dipole cluster localized six (40%). AdSPM spike source was concordant within seizure onset zone in nine (82%) of 11 children with intracranial video EEG. Eleven children with resective surgery achieved seizure freedom with follow-up period of 1.9 ± 1.5 years. Ten (91%) of them had an AdSPM spike source in the resection area. AdSPM can noninvasively and neurophysiologically localize epileptogenic FCDB, whether it overlaps with the dipole cluster or not. This is the first study to localize epileptogenic FCDB using MEG. Copyright © 2018 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

Functional recognition imaging using artificial neural networks: applications to rapid cellular identification via broadband electromechanical response

NASA Astrophysics Data System (ADS)

Nikiforov, M. P.; Reukov, V. V.; Thompson, G. L.; Vertegel, A. A.; Guo, S.; Kalinin, S. V.; Jesse, S.

2009-10-01

Functional recognition imaging in scanning probe microscopy (SPM) using artificial neural network identification is demonstrated. This approach utilizes statistical analysis of complex SPM responses at a single spatial location to identify the target behavior, which is reminiscent of associative thinking in the human brain, obviating the need for analytical models. We demonstrate, as an example of recognition imaging, rapid identification of cellular organisms using the difference in electromechanical activity over a broad frequency range. Single-pixel identification of model Micrococcus lysodeikticus and Pseudomonas fluorescens bacteria is achieved, demonstrating the viability of the method.

Analysis of riverine suspended particulate matter fluxes (Gulf of Lion, Mediterranean Sea) using a synergy of ocean color observations with a 3-D hydrodynamic sediment transport model

NASA Astrophysics Data System (ADS)

Le Fouest, Vincent; Chami, Malik; Verney, Romaric

2015-02-01

The export of riverine suspended particulate matter (SPM) in the coastal ocean has major implications for the biogeochemical cycles. In the Mediterranean Sea (France), the Rhone River inputs of SPM into the Gulf of Lion (GoL) are highly variable in time, which severely impedes the assessment of SPM fluxes. The objectives of this study are (i) to investigate the prediction of the land-to-ocean flux of SPM using the complementarity (i.e., synergy) between a hydrodynamic sediment transport model and satellite observations, and (ii) to analyze the spatial distribution of the SPM export. An original approach that combines the MARS-3D model with satellite ocean color data is proposed. Satellite-derived SPM and light penetration depth are used to initialize MARS-3D and to validate its predictions. A sensitivity analysis is performed to quantify the impact of riverine SPM size composition and settling rate on the horizontal export of SPM. The best agreement between the model and the satellite in terms of SPM spatial distribution and export is obtained for two conditions: (i) when the relative proportion of "heavy and fast" settling particles significantly increases relative to the "light and slow" ones, and (ii) when the settling rate of heavy and light SPM increases by fivefold. The synergy between MARS-3D and the satellite data improved the SPM flux predictions by 48% near the Rhone River mouth. Our results corroborate the importance of implementing satellite observations within initialization procedures of ocean models since data assimilation techniques may fail for river floods showing strong seasonal variability.

SPM investigation of local aging effects in glassy polymers

NASA Astrophysics Data System (ADS)

Crider, Philip

2005-03-01

We investigate the cooperative and heterogeneous nature of glassy dynamics by nanometer-scale probing in a glassy polymer, Polyvinyl-Actetate (PVAc), with a Scanning Force Microscope (SFM). Using ultra-high-vacuum (UHV) Scanning Capacitive Force Microscopy techniques, nanometer-scale capacitive responses are probed. Dielectric relaxation near the glass transition is investigated, and scanning capabilities are utilized to analyze spatial response on a nanometer scale. The results of these studies may yield insight into the understanding of temperature-dependent cooperative length scales, local aging properties, and energy landscape properties of evolving dipole clusters on a mesoscopic scale. Results are used to test the validity and relevance of current models of glassy dynamics.

Ultra low-dose CT attenuation correction in PET SPM

NASA Astrophysics Data System (ADS)

Wang, Shyh-Jen; Yang, Bang-Hung; Tsai, Chia-Jung; Yang, Ching-Ching; Lee, Jason J. S.; Wu, Tung-Hsin

2010-07-01

The use of CT images for attenuation correction (CTAC) allows significantly shorter scanning time and a high quality noise-free attenuation map compared with conventional germanium-68 transmission scan because at least 10 4 times greater of photon flux would be generated from a CT scan under standard operating condition. However, this CTAC technique would potentially introduce more radiation risk to the patients owing to the higher radiation exposure from CT scan. Statistic parameters mapping (SPM) is a prominent technique in nuclear medicine community for the analysis of brain imaging data. The purpose of this study is to assess the feasibility of low-dose CT (LDCT) and ultra low-dose CT (UDCT) in PET SPM applications. The study was divided into two parts. The first part was to evaluate of tracer uptake distribution pattern and quantity analysis by using the striatal phantom to initially assess the feasibility of AC for clinical purpose. The second part was to examine the group SPM analysis using the Hoffman brain phantom. The phantom study is to simulate the human brain and to reduce the experimental uncertainty of real subjects. The initial studies show that the results of PET SPM analysis have no significant differences between LDCT and UDCT comparing to the current used default CTAC. Moreover, the dose of the LDCT is lower than that of the default CT by a factor of 9, and UDCT can even yield a 42 times dose reduction. We have demonstrated the SPM results while using LDCT and UDCT for PET AC is comparable to those using default CT setting, suggesting their feasibility in PET SPM applications. In addition, the necessity of UDCT in PET SPM studies to avoid excess radiation dose is also evident since most of the subjects involved are non-cancer patients or children and some normal subjects are even served as a comparison group in the experiment. It is our belief that additional attempts to decrease the radiation dose would be valuable, especially for children and normal volunteers, to work towards ALARA (as low as reasonably achievable) concept for PET SPM studies.

PREFACE: NC-AFM 2006: Proceedings of the 9th International Conference on Non-contact Atomic Force Microscopy

NASA Astrophysics Data System (ADS)

Tomitori, Masahiko; Onishi, Hiroshi

2007-02-01

The advent of scanning probe microscopy (SPM) in the 1980s has significantly promoted nanoscience and nanotechnology. In particular, non-contact atomic force microscopy (NC-AFM), one of the SPM family, has unique capabilities with high spatial resolution for nanoscale measurements in vacuum, air and liquids. In the last decade we have witnessed the rapid progress of NC-AFM with improved performance and increasing applications. A series of NC-AFM international conferences have greatly contributed to this field. Initiated in Osaka in 1998, the NC-AFM meeting has been followed by annual conferences at Pontresina, Hamburg, Kyoto, Montreal, Dingle, Seattle and Bad Essen. The 9th conference was held in Kobe, Japan, 16-20 July 2006. This special issue of Nanotechnology contains the outstanding contributions of the conference. During the meeting delegates learnt about a number of significant advances. Topics covered atomic resolution imaging of metals, semiconductors, insulators, ionic crystals, oxides, molecular systems, imaging of biological materials in various environments and novel instrumentation. Work also included the characterization of electronic and magnetic properties, tip and cantilever fabrication and characterization, atomic distinction based on analysis of tip-sample interaction, atomic scale manipulation, fabrication of nanostructures using NC-AFM, and related theories and simulations. We are greatly impressed by the increasing number of applications, and convinced that NC-AFM and related techniques are building a bridge to a future nano world, where quantum phenomena will dominate and nano devices will be realized. In addition, a special session on SPM road maps was held as a first trial in the field, where the future prospects of SPM were discussed enthusiastically. The overall success of the NC-AFM 2006 conference was due to the efforts of many individuals and groups with respect to scientific and technological progress, as well as the international exchange among participants. We hope that all of the participants enjoyed the activities of the conference and the town of Kobe. We are indebted to the members of the international steering committee and the local organizing committee for this successful conference. The operation of conference business by the Kobe Convention and Visitors Association, and by the staff in Professor Morita's lab in Osaka University, and Professor Onishi's lab in Kobe University, is greatly acknowledged. We would like to express our sincere gratitude to the 167th committee on Nano-probe Technology of Japan Society for the Promotion of Science, Nanotechnology Researchers Network Center of Japan, Foundation Advanced Technology Institute, Tsutomu Nakauchi Foundation, and all of the exhibitors at the conference for their financial support. The funding from Kobe Advanced ICT Research Center, National Institute of Information and Communications Technology, is greatly appreciated and enabled these proceedings to be published by IOP Publishing (IOP). We also thank the editorial staff of IOP for their professional work in publishing this special issue.

Application of SPM interferometry in MEMS vibration measurement

NASA Astrophysics Data System (ADS)

Tang, Chaowei; He, Guotian; Xu, Changbiao; Zhao, Lijuan; Hu, Jun

2007-12-01

The resonant frequency measurement of cantilever has an important position in MEMS(Micro Electro Mechanical Systems) research. Meanwhile the SPM interferometry is a high-precision optical measurement technique, which can be used in physical quantity measurement of vibration, displacement, surface profile. Hence, in this paper we propose to apply SPM(SPM) interferometry in measuring the vibration of MEMS cantilever and in the experiment the vibration of MEMS cantilever was driven by light source. Then this kind of vibration was measured in nm precision. Finally the relational characteristics of MEMS cantilever vibration under optical excitation can be gotten and the measurement principle is analyzed. This method eliminates the influence on the measuring precision caused by external interference and light intensity change through feedback control loop. Experiment results prove that this measurement method has a good effect.

EDITORIAL: Three decades of scanning tunnelling microscopy that changed the course of surface science Three decades of scanning tunnelling microscopy that changed the course of surface science

NASA Astrophysics Data System (ADS)

Ramachandra Rao, M. S.; Margaritondo, Giorgio

2011-11-01

Three decades ago, with a tiny tip of platinum, the scientific world saw the real space imaging of single atoms with unprecedented spatial resolution. This signalled the birth of one of the most versatile surface probes, based on the physics of quantum mechanical tunnelling: the scanning tunnelling microscope (STM). Invented in 1981 by Gerd Binnig and Heinrich Rohrer of IBM, Zurich, it led to their award of the 1986 Nobel Prize. Atoms, once speculated to be abstract entities used by theoreticians for mere calculations, can be seen to exist for real with the nano-eye of an STM tip that also gives real-space images of molecules and adsorbed complexes on surfaces. From a very fundamental perspective, the STM changed the course of surface science and engineering. STM also emerged as a powerful tool to study various fundamental phenomena relevant to the properties of surfaces in technological applications such as tribology, medical implants, catalysis, sensors and biology—besides elucidating the importance of local bonding geometries and defects, non-periodic structures and the co-existence of nano-scale phases. Atom-level probing, once considered a dream, has seen the light with the evolution of STM. An important off-shoot of STM was the atomic force microscope (AFM) for surface mapping of insulating samples. Then followed the development of a flurry of techniques under the general name of scanning probe microscopy (SPM). These techniques (STM, AFM, MFM, PFM etc) designed for atomic-scale-resolution imaging and spectroscopy, have led to brand new developments in surface analysis. All of these novel methods enabled researchers in recent years to image and analyse complex surfaces on microscopic and nanoscopic scales. All of them utilize a small probe for sensing the surface. The invention of AFM by Gerd Binnig, Calvin Quate and Christopher Gerber opened up new opportunities for characterization of a variety of materials, and various industrial applications could be envisaged. AFM observations of thin-film surfaces give us a picture of surface topography and morphology and any visible defects. The growing importance of ultra-thin films for magnetic recording in hard disk drive systems requires an in-depth understanding of the fundamental mechanisms occurring during growth. This special issue of Journal of Physics D: Applied Physics covers all of the different aspects of SPM that illustrate the achievements of this methodology: nanoscale imaging and mapping (Chiang, and Douillard and Charra), piezoresponse force microscopy (Soergel) and STM engineering (Okuyama and Hamada, and Huang et al). Chiang takes the reader on a journey along the STM imaging of atoms and molecules on surfaces. Jesse and Kalinin explore the band excitations that occur during the corresponding processes. Jia et al propose STM and molecular beam epitaxy as a winning experimental combination at the interface of science and technology. Douillard and Charra describe the high-resolution mapping of plasmonic modes using photoemission and scanning tunnelling microscopy. Cricenti et al demonstrate the importance of SPM in material science and biology. Wiebe et al have probed atomic scale magnetism, revealed by spin polarized scanning tunnelling microscopy. In addition, Simon et al present Fourier transform scanning tunnelling spectroscopy and the possibility to obtain constant energy maps and band dispersion using local measurements. Lackinger and Heckl give a perspective of the use of STM to study covalent intermolecular coupling reactions on surfaces. Okuyama and Hamada investigated hydrogen bond imaging and engineering with STM. Soergel describes the study of substrate-dependent self-assembled CuPc molecules using piezo force microscope (PFM). We are very grateful to the authors and reviewers for the papers in this special issue of Journal of Physics D: Applied Physics. Their contributions have provided a comprehensive picture of the evolution, status and potential of scanning probe microscopy, conveying to the readers the full excitement of this forefront domain of physics.

Suspended particulate matter determines physical speciation of Fe, Mn, and trace metals in surface waters of Loire watershed.

PubMed

Baalousha, Mohamed; Stoll, Serge; Motelica-Heino, Mikaël; Guigues, Nathalie; Braibant, Gilles; Huneau, Frédéric; Le Coustumer, Philippe

2018-02-10

This study investigates the spatiotemporal variability of major and trace elements, dissolved organic carbon (DOC), total dissolved solids (TDS), and suspended particulate matter (SPM) in surface waters of several hydrosystems of the Loire River watershed in France. In particular, this study aims to delineate the impact of the abovementioned water physicochemical parameters on natural iron and manganese physical speciation (homoaggregation/heteroaggregation) among fine colloidal and dissolved (< 10 nm), colloidal (10-450 nm) and particulate (> 450 nm) phases in Loire River watershed. Results show that the chemistry of the Loire River watershed is controlled by two end members: magmatic and metamorphic petrographic context on the upper part of the watershed; and sedimentary rocks for the middle and low part of the Loire. The percentage of particulate Fe and Mn increased downstream concurrent with the increase in SPM and major cations concentration, whereas the percentage of colloidal Fe and Mn decreased downstream. Transmission electron microscopy analyses of the colloidal and particulate fractions (from the non-filtered water sample) revealed that heteroaggregation of Fe and Mn rich natural nanoparticles and natural organic matter to the particulate phase is the dominant mechanism. The heteroaggregation controls the partitioning of Fe and Mn in the different fractions, potentially due to the increase in the ionic strength, and divalent cations concentration downstream, and SPM concentration. These findings imply that SPM concentration plays an important role in controlling the fate and behavior of Fe and Mn in various sized fractions. Graphical abstract Physical speciation by heteroaggregation of (Fe-Mn) compounds: high [SPM] → [Fe-Mn] particulate faction; low {SPM] → [Fe-Mn] colloid-dissolved fraction.

Analytical Optimization of the Net Residual Dispersion in SPM-Limited Dispersion-Managed Systems

NASA Astrophysics Data System (ADS)

Xiao, Xiaosheng; Gao, Shiming; Tian, Yu; Yang, Changxi

2006-05-01

Dispersion management is an effective technique to suppress the nonlinear impairment in fiber transmission systems, which includes tuning the amounts of precompensation, residual dispersion per span (RDPS), and net residual dispersion (NRD) of the systems. For self-phase modulation (SPM)-limited systems, optimizing the NRD is necessary because it can greatly improve the system performance. In this paper, an analytical method is presented to optimize NRD for SPM-limited dispersion-managed systems. The method is based on the correlation between the nonlinear impairment and the output pulse broadening of SPM-limited systems; therefore, dispersion-managed systems can be optimized through minimizing the output single-pulse broadening. A set of expressions is derived to calculate the output pulse broadening of the SPM-limited dispersion-managed system, from which the analytical result of optimal NRD is obtained. Furthermore, with the expressions of pulse broadening, how the nonlinear impairment depends on the amounts of precompensation and RDPS can be revealed conveniently.

Planar-type ferromagnetic tunnel junctions fabricated by SPM local oxidation

NASA Astrophysics Data System (ADS)

Tomoda, Y.; Kayashima, S.; Ogino, T.; Motoyama, M.; Takemura, Y.; Shirakashi, J.

Nanometer-scale oxide wires were fabricated by local oxidation nanolithography using scanning probe microscope (SPM). This technique was applied to the fabrication of planar-type Ni/Ni oxide/Ni ferromagnetic tunnel junctions. In order to induce magnetic shape anisotropy, asymmetrical channel structure was patterned by conventional photolithography and wet etching processes. The magnetoresistance (MR) characteristics were clearly shown in the planar-type Ni/Ni oxide/Ni ferromagnetic tunnel junctions. MR ratio of above 100% was obtained at 17 K. This result suggests that the local oxidation nanolithography using SPM is useful for the application to planar-type ferromagnetic tunnel junctions.

High sensitivity and high resolution element 3D analysis by a combined SIMS–SPM instrument

PubMed Central

Wirtz, Tom

2015-01-01

Summary Using the recently developed SIMS–SPM prototype, secondary ion mass spectrometry (SIMS) data was combined with topographical data from the scanning probe microscopy (SPM) module for five test structures in order to obtain accurate chemical 3D maps: a polystyrene/polyvinylpyrrolidone (PS/PVP) polymer blend, a nickel-based super-alloy, a titanium carbonitride-based cermet, a reticle test structure and Mg(OH)2 nanoclusters incorporated inside a polymer matrix. The examples illustrate the potential of this combined approach to track and eliminate artefacts related to inhomogeneities of the sputter rates (caused by samples containing various materials, different phases or having a non-flat surface) and inhomogeneities of the secondary ion extraction efficiencies due to local field distortions (caused by topography with high aspect ratios). In this respect, this paper presents the measured relative sputter rates between PVP and PS as well as in between the different phases of the TiCN cermet. PMID:26171285

Versatile variable temperature and magnetic field scanning probe microscope for advanced material research

NASA Astrophysics Data System (ADS)

Jung, Jin-Oh; Choi, Seokhwan; Lee, Yeonghoon; Kim, Jinwoo; Son, Donghyeon; Lee, Jhinhwan

2017-10-01

We have built a variable temperature scanning probe microscope (SPM) that covers 4.6 K-180 K and up to 7 T whose SPM head fits in a 52 mm bore magnet. It features a temperature-controlled sample stage thermally well isolated from the SPM body in good thermal contact with the liquid helium bath. It has a 7-sample-holder storage carousel at liquid helium temperature for systematic studies using multiple samples and field emission targets intended for spin-polarized spectroscopic-imaging scanning tunneling microscopy (STM) study on samples with various compositions and doping conditions. The system is equipped with a UHV sample preparation chamber and mounted on a two-stage vibration isolation system made of a heavy concrete block and a granite table on pneumatic vibration isolators. A quartz resonator (qPlus)-based non-contact atomic force microscope (AFM) sensor is used for simultaneous STM/AFM operation for research on samples with highly insulating properties such as strongly underdoped cuprates and strongly correlated electron systems.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Sangmo; Paranthaman, Mariappan Parans; Noh, Tae Won

The voltage spectroscopies in scanning probe microscopy (SPM) techniques are widely used to investigate the electrochemical processes in nanoscale volumes, which are important for current key applications, such as batteries, fuel cells, catalysts, and memristors. The spectroscopic measurements are commonly performed on a grid of multiple points to yield spatially resolved maps of reversible and irreversible electrochemical functionalities. Hence, the spacing between measurement points is an important parameter to be considered, especially for irreversible electrochemical processes. Here, we report nonlocal electrochemical dynamics in chains of Ag particles fabricated by the SPM tip on a silver ion solid electrolyte. When themore » grid spacing is small compared with the size of the formed Ag particles, anomalous chains of unequally sized particles with double periodicity evolve. This behavior is ascribed to a proximity effect during the tip-induced electrochemical process, specifically, size-dependent silver particle growth following the contact between the particles. In addition, fractal shape evolution of the formed Ag structures indicates that the growth-limiting process changes from Ag +/Ag redox reaction to Ag +-ion diffusion with the increase in the applied voltage and pulse duration. Our study shows that characteristic shapes of the electrochemical products are good indicators for determining the underlying growth-limiting process, and emergence of complex phenomena during spectroscopic mapping of electrochemical functionalities.« less

Whole brain analysis of postmortem density changes of grey and white matter on computed tomography by statistical parametric mapping.

PubMed

Nishiyama, Yuichi; Kanayama, Hidekazu; Mori, Hiroshi; Tada, Keiji; Yamamoto, Yasushi; Katsube, Takashi; Takeshita, Haruo; Kawakami, Kazunori; Kitagaki, Hajime

2017-06-01

This study examined the usefulness of statistical parametric mapping (SPM) for investigating postmortem changes on brain computed tomography (CT). This retrospective study included 128 patients (23 - 100 years old) without cerebral abnormalities who underwent unenhanced brain CT before and after death. The antemortem CT (AMCT) scans and postmortem CT (PMCT) scans were spatially normalized using our original brain CT template, and postmortem changes of CT values (in Hounsfield units; HU) were analysed by the SPM technique. Compared with AMCT scans, 58.6 % and 98.4 % of PMCT scans showed loss of the cerebral sulci and an unclear grey matter (GM)-white matter (WM) interface, respectively. SPM analysis revealed a significant decrease in cortical GM density within 70 min after death on PMCT scans, suggesting cytotoxic brain oedema. Furthermore, there was a significant increase in the density of the WM, lenticular nucleus and thalamus more than 120 min after death. The SPM technique demonstrated typical postmortem changes on brain CT scans, and revealed that the unclear GM-WM interface on early PMCT scans is caused by a rapid decrease in cortical GM density combined with a delayed increase in WM density. SPM may be useful for assessment of whole brain postmortem changes. • The original brain CT template achieved successful normalization of brain morphology. • Postmortem changes in the brain were independent of sex. • Cortical GM density decreased rapidly after death. • WM and deep GM densities increased following cortical GM density change. • SPM could be useful for assessment of whole brain postmortem changes.

Specific interaction of postsynaptic densities with membrane rafts isolated from synaptic plasma membranes.

PubMed

Liu, Qian; Yao, Wei-Dong; Suzuki, Tatsuo

2013-06-01

Postsynaptic membrane rafts are believed to play important roles in synaptic signaling, plasticity, and maintenance. We recently demonstrated the presence, at the electron microscopic level, of complexes consisting of membrane rafts and postsynaptic densities (PSDs) in detergent-resistant membranes (DRMs) prepared from synaptic plasma membranes (SPMs) ( Suzuki et al., 2011 , J Neurochem, 119, 64-77). To further explore these complexes, here we investigated the nature of the binding between purified SPM-DRMs and PSDs in vitro. In binding experiments, we used SPM-DRMs prepared after treating SPMs with n-octyl-β-d-glucoside, because at concentrations of 1.0% or higher it completely separates SPM-DRMs and PSDs, providing substantially PSD-free unique SPM-DRMs as well as DRM-free PSDs. PSD binding to PSD-free DRMs was identified by mass spectrometry, Western blotting, and electron microscopy. PSD proteins were not incorporated into SPMs, and significantly less PSD proteins were incorporated into DRMs prepared from liver membranes, providing in vitro evidence that binding of PSDs to DRMs is specific and suggestion of the presence of specific interacting molecules. These specific interactions may have important roles in synaptic development, function, and plasticity in vivo. In addition, the binding system we developed may be a good tool to search for binding molecules and binding mechanisms between PSDs and rafts.

Characterization of microcracks by application of digital image correlation to SPM images

NASA Astrophysics Data System (ADS)

Keller, Juergen; Gollhardt, Astrid; Vogel, Dietmar; Michel, Bernd

2004-07-01

With the development of micro- and nanotechnological products such as sensors, MEMS/NEMS and their broad application in a variety of market segments new reliability issues will arise. The increasing interface-to-volume ratio in highly integrated systems and nanoparticle filled materials and unsolved questions of size effect of nanomaterials are challenges for experimental reliability evaluation. To fulfill this needs the authors developed the nanoDAC method (nano Deformation Analysis by Correlation), which allows the determination and evaluation of 2D displacement fields based on scanning probe microscopy (SPM) data. In-situ SPM scans of the analyzed object are carried out at different thermo-mechanical load states. The obtained topography-, phase- or error-images are compared utilizing grayscale cross correlation algorithms. This allows the tracking of local image patterns of the analyzed surface structure. The measurement results of the nanoDAC method are full-field displacement and strain fields. Due to the application of SPM equipment deformations in the micro-, nanometer range can be easily detected. The method can be performed on bulk materials, thin films and on devices i.e microelectronic components, sensors or MEMS/NEMS. Furthermore, the characterization and evaluation of micro- and nanocracks or defects in bulk materials, thin layers and at material interfaces can be carried out.

An Automated Method of Scanning Probe Microscopy (SPM) Data Analysis and Reactive Site Tracking for Mineral-Water Interface Reactions Observed at the Nanometer Scale

NASA Astrophysics Data System (ADS)

Campbell, B. D.; Higgins, S. R.

2008-12-01

Developing a method for bridging the gap between macroscopic and microscopic measurements of reaction kinetics at the mineral-water interface has important implications in geological and chemical fields. Investigating these reactions on the nanometer scale with SPM is often limited by image analysis and data extraction due to the large quantity of data usually obtained in SPM experiments. Here we present a computer algorithm for automated analysis of mineral-water interface reactions. This algorithm automates the analysis of sequential SPM images by identifying the kinetically active surface sites (i.e., step edges), and by tracking the displacement of these sites from image to image. The step edge positions in each image are readily identified and tracked through time by a standard edge detection algorithm followed by statistical analysis on the Hough Transform of the edge-mapped image. By quantifying this displacement as a function of time, the rate of step edge displacement is determined. Furthermore, the total edge length, also determined from analysis of the Hough Transform, combined with the computed step speed, yields the surface area normalized rate of the reaction. The algorithm was applied to a study of the spiral growth of the calcite(104) surface from supersaturated solutions, yielding results almost 20 times faster than performing this analysis by hand, with results being statistically similar for both analysis methods. This advance in analysis of kinetic data from SPM images will facilitate the building of experimental databases on the microscopic kinetics of mineral-water interface reactions.

Temporal contrast enhancement of a femtosecond fiber CPA system by filtering of SPM broadened spectra

NASA Astrophysics Data System (ADS)

Buldt, J.; Müller, M.; Klas, R.; Eidam, T.; Limpert, J.; Tünnermann, A.

2018-02-01

We present a novel approach for temporal contrast enhancement of energetic laser pulses by filtered SPM broadened spectra. A measured temporal contrast enhancement by at least 7 orders of magnitude in a simple setup has been achieved. This technique is applicable to a wide range of laser parameters and poses a highly efficient alternative to existing contrast-enhancement methods.

Characterization of structural and electrostatic complexity in pentacene thin films by scanning probe microscopy

NASA Astrophysics Data System (ADS)

Puntambekar, Kanan Prakash

The advancement of organic electronics for applications in solar energy conversion, printed circuitry, displays, and solid-state lighting depends upon optimization of structure and properties for a variety of organic semiconductor interfaces. Organic semiconductor/insulator (O/I) and organic-metal (O/M) interfaces, in particular, are critical to the operation of organic thin film transistors (OTFTs) currently being developed for printed flexible electronics. Scanning probe microscopy (SPM) is a powerful tool to isolate and characterize the bottlenecks to charge transport at these interfaces. This thesis establishes a direct correlation between the structural disorder and electrical complexity at these interfaces, using various SPM based methods and discusses the implications of such complexity on device performance. To examine the O/M interfaces, surface potentials of operating pentacene TFTs with two different contact geometries (bottom or top) were mapped by Kelvin probe force microscopy (KFM). The surface potential distribution was used to isolate the potential drops at the source and drain contacts. Simultaneously obtained topography and surface potential maps elucidated the correlation between the morphology and contact resistance at the O/M interface; the bottom contact TFTs were observed to be contact limited at large gate voltages, while the top contact TFTs were not contact limited. A direct correlation between structural defects and electric potential variations at the pentacene and silicon dioxide, a common insulator, is demonstrated. Lateral force microscopy (LFM) generates striking images of the polycrystalline microstructure of a monolayer thick pentacene film, allowing clear visualization of the grain boundary network. Further more, surface potential wells localized at the grain boundaries were observed by KFM, suggesting that the grain boundaries may serve as charge carrier (hole) traps. Line dislocations were also revealed in the second monolayer by chemical etching and SPM and produce strong variations in the surface potential that must affect the interfacial charge conductance. Structural disorder at the O/I and O/M interfaces degrades both injection and transport of charge, and therefore needs to be minimized. Thus both visualization and correlation of structural and electrical complexity at these interfaces have important implications for understanding electrical transport in OTFTs and for defining strategies to improve device performance.

Mass-specific scattering coefficient for natural minerogenic particle populations: particle size distribution effect and closure analyses.

PubMed

Peng, Feng; Effler, Steve W

2012-05-01

The relationship between the particulate scattering coefficient (b(p)) and the concentration of suspended particulate matter (SPM), as represented by the mass-specific scattering coefficient of particulates (b(p)*=b(p)/SPM), depends on particle size distribution (PSD). This dependence is quantified for minerogenic particle populations in this paper through calculations of b(p)* for common minerals as idealized populations (monodispersed spheres); contemporaneous measurements of b(p), SPM, and light-scattering attributes of mineral particles with scanning electron microscopy interfaced with automated image and x-ray analyses (SAX), for a connected stream-reservoir system where minerogenic particles dominate b(p); and estimates of b(p) and its size dependency (through SAX results-driven Mie theory calculations), particle volume concentration, and b(p)*. Modest changes in minerogenic PSDs are shown to result in substantial variations in b(p)*. Good closure of the SAX-based estimates of b(p) and particle volume concentration with bulk measurements is demonstrated. Converging relationships between b(p)* and particle size, developed from three approaches, were well described by power law expressions.

SPM oxidation and parallel writing on zirconium nitride thin films

NASA Astrophysics Data System (ADS)

Farkas, N.; Comer, J. R.; Zhang, G.; Evans, E. A.; Ramsier, R. D.; Dagata, J. A.

2005-07-01

Systematic investigation of the SPM oxidation process of sputter-deposited ZrN thin films is reported. During the intrinsic part of the oxidation, the density of the oxide increases until the total oxide thickness is approximately twice the feature height. Further oxide growth is sustainable as the system undergoes plastic flow followed by delamination from the ZrN-silicon interface keeping the oxide density constant. ZrN exhibits superdiffusive oxidation kinetics in these single tip SPM studies. We extend this work to the fabrication of parallel oxide patterns 70 nm in height covering areas in the square centimeter range. This simple, quick, and well-controlled parallel nanolithographic technique has great potential for biomedical template fabrication.

Evaluation of the Applicability of Solar and Lamp Radiometric Calibrations of a Precision Sun Photometer Operating Between 300 and 1025 nm

NASA Technical Reports Server (NTRS)

Schmid, Beat; Spyak, Paul R.; Biggar, Stuart F.; Joerg, Sekler; Ingold, Thomas; Maetzler, Christian; Kaempfer, Niklaus

2000-01-01

Over a period of 3 year a precision Sun photometer (SPM) operating between 300 and 1025 nm was calibrated four times at three different high-mountain sites in Switzerland, Germany, and the United States by means of the Langley-plot technique. We found that for atmospheric window wavelengths the total error (2 sigma-statistical plus systematic errors) of the calibration constants V(sub 0)(lambda), the SPM voltage in the absence of any attenuating atmosphere, can be kept below 1.60% in the UV-A and blue, 0.9% in the mid-visible, and 0.6% in the near-infra red spectral region. For SPM channels within strong water-vapor or ozone absorption bands a modified Langley-plot technique was used to determine V(sub 0)(lambda) with a lower accuracy. Within the same period of time, we calibrated the SPM five times using irradiance standard lamps in the optical labs of the Physikalisch-Meteorologisches Observatorium Davos and World Radiation Center, Switzerland, and of the Remote Sensing Group of the Optical Sciences Center, University of Arizona, Tucson, Arizona. The lab calibration method requires knowledge of the extraterrestrial spectral irradiance. When we refer the standard lamp results to the World Radiation Center extraterrestrial solar irradiance spectrum, they agree with the Langley results within 2% at 6 or 13 SPM wavelengths. The largest disagreement (4.4%) is found for the channel centered at 610 nm. The results of these intercomparisons change significantly when the lamp results are referred to two different extraterrestrial solar irradiance spectra that have become recently available.

Mechanically adjustable single-molecule transistors and stencil mask nanofabrication of high-resolution scanning probes

NASA Astrophysics Data System (ADS)

Champagne, Alexandre

This dissertation presents the development of two original experimental techniques to probe nanoscale objects. The first one studies electronic transport in single organic molecule transistors in which the source-drain electrode spacing is mechanically adjustable. The second involves the fabrication of high-resolution scanning probe microscopy sensors using a stencil mask lithography technique. We describe the fabrication of transistors in which a single organic molecule can be incorporated. The source and drain leads of these transistors are freely suspended above a flexible substrate, and their spacing can be adjusted by bending the substrate. We detail the technology developed to carry out measurements on these samples. We study electronic transport in single C60 molecules at low temperature. We observe Coulomb blockaded transport and can resolve the discrete energy spectrum of the molecule. We are able to mechanically tune the spacing between the electrodes (over a range of 5 A) to modulate the lead-molecule coupling, and can electrostatically tune the energy levels on the molecule by up to 160 meV using a gate electrode. Initial progress in studying different transport regimes in other molecules is also discussed. We present a lithographic process that allows the deposition of metal nanostructures with a resolution down to 10 nm directly onto atomic force microscope (AFM) tips. We show that multiple layers of lithography can be deposited and aligned. We fabricate high-resolution magnetic force microscopy (MFM) probes using this method and discuss progress to fabricate other scanning probe microscopy (SPM) sensors.

Optical Characterisation of Suspended Particles in the Mackenzie River Plume (Canadian Arctic Ocean) and Implications for Ocean Colour Remote Sensing

NASA Technical Reports Server (NTRS)

Doxaran, D.; Ehn, J.; Belanger, S.; Matsuoka, A.; Hooker, S.; Babin, M.

2012-01-01

Climate change significantly impacts Arctic shelf regions in terms of air temperature, ultraviolet radiation, melting of sea ice, precipitation, thawing of permafrost and coastal erosion. Direct consequences have been observed on the increasing Arctic river flow and a large amount of organic carbon sequestered in soils at high latitudes since the last glacial maximum can be expected to be delivered to the Arctic Ocean during the coming decade. Monitoring the fluxes and fate of this terrigenous organic carbon is problematic in such sparsely populated regions unless remote sensing techniques can be developed and proved to be operational. The main objective of this study is to develop an ocean colour algorithm to operationally monitor dynamics of suspended particulate matter (SPM) on the Mackenzie River continental shelf (Canadian Arctic Ocean) using satellite imagery. The water optical properties are documented across the study area and related to concentrations of SPM and particulate organic carbon (POC). Robust SPM and POC : SPM proxies are identified, such as the light backscattering and attenuation coefficients, and relationships are established between these optical and biogeochemical parameters. Following a semi-analytical approach, a regional SPM quantification relationship is obtained for the inversion of the water reflectance signal into SPM concentration. This relationship is reproduced based on independent field optical measurements. It is successfully applied to a selection of MODIS satellite data which allow estimating fluxes at the river mouth and monitoring the extension and dynamics of the Mackenzie River surface plume in 2009, 2010 and 2011. Good agreement is obtained with field observations representative of the whole water column in the river delta zone where terrigenous SPM is mainly constrained (out of short periods of maximum river outflow). Most of the seaward export of SPM is observed to occur within the west side of the river mouth. Future work will require the validation of the developed SPM regional algorithm based on match-ups with field measurements, then the routine application to ocean colour satellite data in order to better estimate the fluxes and fate of SPM and POC delivered by the Mackenzie River to the Arctic Ocean.

Vacuum scanning capillary photoemission microscopy.

PubMed

Aseyev, S A; Cherkun, A P; Mironov, B N; Petrunin, V V; Chekalin, S V

2017-08-01

We demonstrate the use of a conical capillary in a scanning probe microscopy for surface analysis. The probe can measure photoemission from a substrate by transmitting photoelectrons along the capillary as a function of probe position. The technique is demonstrated on a model substrate consisting of a gold reflecting layer on a compact disc which has been illuminated by an unfocused laser beam with a wavelength 400nm, from a femtosecond laser with a beam size of 4mm. A quartz capillary with a 2-µm aperture has been used in the experiments. The period of gold microstructure, shown to be 1.6µ, was measured by the conical probe operating in shear force mode. In shear force regime, the dielectric capillary has been used as a "classical" SPM tip, which provided images reflecting the surface topology. In a photoelectron regime photoelectrons passed through hollow tip and entered a detector. The spatial distribution of the recorded photoelectrons consisted of periodic mountain-valley strips, resembling the surface profile of the sample. Submicron spatial resolution has been achieved. This approach paves the way to study pulsed photodesorption of large organic molecular ions with high spatial and element resolution using the combination of a hollow-tip scanner with time-of-flight technique. Copyright © 2017 Elsevier B.V. All rights reserved.

Novel dextran-spermine conjugates as transfecting agents: comparing water-soluble and micellar polymers.

PubMed

Eliyahu, H; Makovitzki, A; Azzam, T; Zlotkin, A; Joseph, A; Gazit, D; Barenholz, Y; Domb, A J

2005-03-01

Recently, a novel cationic polymer, dextran-spermine (D-SPM) was developed for gene delivery. An efficient transfection was obtained using this polycation for a variety of genes and cell lines in serum-free or serum-poor medium. However, transfection using the water-soluble D-SPM-based polyplexes decreased with increasing serum concentration in cell culture in a concentration-dependent manner, reaching 95% inhibition at 50% serum in the cell growth medium. In order to overcome this obstacle, oleyl derivatives of D-SPM (which form micelles in aqueous phase) were synthesized at 1, 10, and 20 mol% of oleyl moiety to polymer epsilon-NH2 to form N-oleyl-D-SPM (ODS). Polyplexes based on ODS transfected well in medium containing 50% serum. Comparison with polyplexes based on well-established polymers (branched and linear polyethyleneimine) and with DOTAP/Cholesterol lipoplexes showed that regarding beta-galactosidase transgene expression level and cytotoxicity in tissue culture, the D-SPM and ODS compare well with the above polyplexes and lipoplexes. Intracellular trafficking using FITC-labeled ODS and Rhodamine-labeled pGeneGrip plasmid cloned with hBMP2 monitored by confocal microscopy revealed that during the transfection process the fluorescent-labeled polymer concentrates in the Golgi apparatus and around the nucleus, while the cell cytoplasm was free of fluorescent particles, suggesting that the polyplexes move in the cell toward the nucleus by vesicular transport through the cytoplasm and not by a random diffusion. We found that the plasmids penetrate the cell nucleus without the polymer. Preliminary results in zebra fish and mice demonstrate the potential of ODS to serve as an efficient nonviral vector for in vivo transfection.

Analysis of Scanned Probe Images for Magnetic Focusing in Graphene

DOE PAGES

Bhandari, Sagar; Lee, Gil-Ho; Kim, Philip; ...

2017-02-21

We have used cooled scanning probe microscopy (SPM) to study electron motion in nanoscale devices. The charged tip of the microscope was raster-scanned at constant height above the surface as the conductance of the device was measured. The image charge scatters electrons away, changing the path of electrons through the sample. Using this technique, we imaged cyclotron orbits that flow between two narrow contacts in the magnetic focusing regime for ballistic hBN–graphene–hBN devices. We present herein an analysis of our magnetic focusing imaging results based on the effects of the tip-created charge density dip on the motion of ballistic electrons.more » The density dip locally reduces the Fermi energy, creating a force that pushes electrons away from the tip. When the tip is above the cyclotron orbit, electrons are deflected away from the receiving contact, creating an image by reducing the transmission between contacts. The data and our analysis suggest that the graphene edge is rather rough, and electrons scattering off the edge bounce in random directions. However, when the tip is close to the edge, it can enhance transmission by bouncing electrons away from the edge, toward the receiving contact. Our results demonstrate that cooled SPM is a promising tool to investigate the motion of electrons in ballistic graphene devices.« less

Analysis of Scanned Probe Images for Magnetic Focusing in Graphene

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhandari, Sagar; Lee, Gil-Ho; Kim, Philip

We have used cooled scanning probe microscopy (SPM) to study electron motion in nanoscale devices. The charged tip of the microscope was raster-scanned at constant height above the surface as the conductance of the device was measured. The image charge scatters electrons away, changing the path of electrons through the sample. Using this technique, we imaged cyclotron orbits that flow between two narrow contacts in the magnetic focusing regime for ballistic hBN–graphene–hBN devices. We present herein an analysis of our magnetic focusing imaging results based on the effects of the tip-created charge density dip on the motion of ballistic electrons.more » The density dip locally reduces the Fermi energy, creating a force that pushes electrons away from the tip. When the tip is above the cyclotron orbit, electrons are deflected away from the receiving contact, creating an image by reducing the transmission between contacts. The data and our analysis suggest that the graphene edge is rather rough, and electrons scattering off the edge bounce in random directions. However, when the tip is close to the edge, it can enhance transmission by bouncing electrons away from the edge, toward the receiving contact. Our results demonstrate that cooled SPM is a promising tool to investigate the motion of electrons in ballistic graphene devices.« less

Nano-suspension coating as a technique to modulate the drug release from controlled porosity osmotic pumps for a soluble agent.

PubMed

Bahari, Leila Azharshekoufeh; Javadzadeh, Yousef; Jalali, Mohammad Barzegar; Johari, Peyvand; Nokhodchi, Ali; Shokri, Javad

2017-05-01

In controlled porosity osmotic pumps (CPOP), usually finding a single solvent with a capability to dissolve both film former (hydrophobic) and pore former (hydrophilic) is extremely challenging. Therefore, the aim of the present investigation was to tackle the issue associated with controlled porosity osmotic pump (CPOP) system using nano-suspension coating method. In the present study 4-Amino pyridine was used as a highly water soluble drug. In this method, a hydrophilic pore former (sucrose or mannitol) in nano range was suspended in polymeric coating solution using ball-mill. The performance of the prepared formulations was assessed in terms of D 12h (cumulative release percent after 12h), Dev zero (mean percent deviation of drug release from zero order kinetic), t L (lag time of the drug release) and RSQ zero . The results revealed that gelling agent amount (HPMC E 15LV ) in core and pore former concentration in SPM had crucial effect on SPM integrity. All the optimised formulations showed a burst drug release due to fast dissolving nature of the pore formers. Results obtained from scanning electron microscopy demonstrated the formation of nanopores in the membrane where the drug release takes place via these nanopores. Nano suspension coating method can be introduced as novel method in formulation of CPOPs. Copyright © 2017 Elsevier B.V. All rights reserved.

Nanoparticle shape evolution and proximity effects during tip-induced electrochemical processes

DOE PAGES

Yang, Sangmo; Paranthaman, Mariappan Parans; Noh, Tae Won; ...

2016-01-08

The voltage spectroscopies in scanning probe microscopy (SPM) techniques are widely used to investigate the electrochemical processes in nanoscale volumes, which are important for current key applications, such as batteries, fuel cells, catalysts, and memristors. The spectroscopic measurements are commonly performed on a grid of multiple points to yield spatially resolved maps of reversible and irreversible electrochemical functionalities. Hence, the spacing between measurement points is an important parameter to be considered, especially for irreversible electrochemical processes. Here, we report nonlocal electrochemical dynamics in chains of Ag particles fabricated by the SPM tip on a silver ion solid electrolyte. When themore » grid spacing is small compared with the size of the formed Ag particles, anomalous chains of unequally sized particles with double periodicity evolve. This behavior is ascribed to a proximity effect during the tip-induced electrochemical process, specifically, size-dependent silver particle growth following the contact between the particles. In addition, fractal shape evolution of the formed Ag structures indicates that the growth-limiting process changes from Ag +/Ag redox reaction to Ag +-ion diffusion with the increase in the applied voltage and pulse duration. Our study shows that characteristic shapes of the electrochemical products are good indicators for determining the underlying growth-limiting process, and emergence of complex phenomena during spectroscopic mapping of electrochemical functionalities.« less

Pulse electrochemical meso/micro/nano ultraprecision machining technology.

PubMed

Lee, Jeong Min; Kim, Young Bin; Park, Jeong Woo

2013-11-01

This study demonstrated meso/micro/nano-ultraprecision machining through electrochemical reactions using intermittent DC pulses. The experiment focused on two machining methods: (1) pulse electrochemical polishing (PECP) of stainless steel, and (2) pulse electrochemical nano-patterning (PECNP) on a silicon (Si) surface, using atomic force microscopy (AFM) for fabrication. The dissolution reaction at the stainless steel surface following PECP produced a very clean, smooth workpiece. The advantages of the PECP process included improvements in corrosion resistance, deburring of the sample surface, and removal of hydrogen from the stainless steel surface as verified by time-of-flight secondary-ion mass spectrometry (TOF-SIMS). In PECNP, the electrochemical reaction generated within water molecules produced nanoscale oxide textures on a Si surface. Scanning probe microscopy (SPM) was used to evaluate nanoscale-pattern processing on a Si wafer surface produced by AFM-PECNP For both processes using pulse electrochemical reactions, three-dimensional (3-D) measurements and AFM were used to investigate the changes on the machined surfaces. Preliminary results indicated the potential for advancing surface polishing techniques and localized micro/nano-texturing technology using PECP and PECNP processes.

Touching is believing: interrogating halide perovskite solar cells at the nanoscale via scanning probe microscopy

NASA Astrophysics Data System (ADS)

Li, Jiangyu; Huang, Boyuan; Nasr Esfahani, Ehsan; Wei, Linlin; Yao, Jianjun; Zhao, Jinjin; Chen, Wei

2017-10-01

Halide perovskite solar cells based on CH3NH3PbI3 and related materials have emerged as the most exciting development in the next generation photovoltaic technologies, yet the microscopic phenomena involving photo-carriers, ionic defects, spontaneous polarization, and molecular vibration and rotation interacting with numerous grains, grain boundaries, and interfaces are still inadequately understood. In fact, there is still need for an effective method to interrogate the local photovoltaic properties of halide perovskite solar cells that can be directly traced to their microstructures on one hand and linked to their device performance on the other hand. In this perspective, we propose that scanning probe microscopy (SPM) techniques have great potential to realize such promises at the nanoscale, and highlight some of the recent progresses and challenges along this line of investigation toward local probing of photocurrent, work function, ionic activities, polarization switching, and chemical degradation. We also emphasize the importance of multi-modality imaging, in-operando scanning, big data analysis, and multidisciplinary collaboration for further studies toward fully understanding of these complex systems.

Synthesis and characterization of micro/nanoscopic Pb(Zr0.52Ti0.48)O3 fibers by electrospinning

NASA Astrophysics Data System (ADS)

Wang, Y.; Furlan, R.; Ramos, I.; Santiago-Aviles, J. J.

Micro/nanoscopic Pb(Zr0.52Ti0.48)O3 fibers were synthesized from commercially available zirconium n-pro-poxide, titanium isopropoxide, and lead 2-ethylhexanoate. Using xylene as a solvent, they were mixed to form a precursor solution with a suitable viscosity for electrospinning. The solution was analyzed using thermo-gravimetric and differential thermal methods. Ultra-fine fibers and mats were electrostatically drawn from the precursor solution. The as-deposited materials were sintered for 2 h at 400, 500, 600, 700 and 800 °C, respectively. Sintered mats or fibers were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), Auger electron spectroscopy (AES), Raman micro-spectrometry and scanning-probe microscopy (SPM). The SEM results revealed that the fibers had diameters varying from hundreds of nanometers to 10 μm. Using AES, the elements Pb, Zr, Ti and O, as well as residual C, were detected on the surface of the fibers. Raman and XRD spectra indicated that the precursors began to transform into the intermediate pyrochlore phase at 400 °C, followed by the perovskite Pb(Zr0.52Ti0.48)O3 phase above 600 °C. Scanning-probe microscopy (SPM), operated in the piezo-response imaging mode, revealed spontaneous polarization domains in the fibers, with diameters ranging from 100 to 500 nm.

Scanning Ion Conductance Microscopy of Live Keratinocytes

NASA Astrophysics Data System (ADS)

Hegde, V.; Mason, A.; Saliev, T.; Smith, F. J. D.; McLean, W. H. I.; Campbell, P. A.

2012-07-01

Scanning ion conductance microscopy (SICM) is perhaps the least well known technique from the scanning probe microscopy (SPM) family of instruments. As with its more familiar counterpart, atomic force microscopy (AFM), the technique provides high-resolution topographic imaging, with the caveat that target structures must be immersed in a conducting solution so that a controllable ion current may be utilised as the basis for feedback. In operation, this non-contact characteristic of SICM makes it ideal for the study of delicate structures, such as live cells. Moreover, the intrinsic architecture of the instrument, incorporating as it does, a scanned micropipette, lends itself to combination approaches with complementary techniques such as patch-clamp electrophysiology: SICM therefore boasts the capability for both structural and functional imaging. For the present observations, an ICnano S system (Ionscope Ltd., Melbourn, UK) operating in 'hopping mode' was used, with the objective of assessing the instrument's utility for imaging live keratinocytes under physiological buffers. In scans employing cultured HaCaT cells (spontaneously immortalised, human keratinocytes), we compared the qualitative differences of live cells imaged with SICM and AFM, and also with their respective counterparts after chemical fixation in 4% paraformaldehyde. Characteristic surface microvilli were particularly prominent in live cell imaging by SICM. Moreover, time lapse SICM imaging on live cells revealed that changes in the pattern of microvilli could be tracked over time. By comparison, AFM imaging on live cells, even at very low contact forces (

Harnessing Big Data for Systems Pharmacology

PubMed Central

Xie, Lei; Draizen, Eli J.; Bourne, Philip E.

2017-01-01

Systems pharmacology aims to holistically understand mechanisms of drug actions to support drug discovery and clinical practice. Systems pharmacology modeling (SPM) is data driven. It integrates an exponentially growing amount of data at multiple scales (genetic, molecular, cellular, organismal, and environmental). The goal of SPM is to develop mechanistic or predictive multiscale models that are interpretable and actionable. The current explosions in genomics and other omics data, as well as the tremendous advances in big data technologies, have already enabled biologists to generate novel hypotheses and gain new knowledge through computational models of genome-wide, heterogeneous, and dynamic data sets. More work is needed to interpret and predict a drug response phenotype, which is dependent on many known and unknown factors. To gain a comprehensive understanding of drug actions, SPM requires close collaborations between domain experts from diverse fields and integration of heterogeneous models from biophysics, mathematics, statistics, machine learning, and semantic webs. This creates challenges in model management, model integration, model translation, and knowledge integration. In this review, we discuss several emergent issues in SPM and potential solutions using big data technology and analytics. The concurrent development of high-throughput techniques, cloud computing, data science, and the semantic web will likely allow SPM to be findable, accessible, interoperable, reusable, reliable, interpretable, and actionable. PMID:27814027

Harnessing Big Data for Systems Pharmacology.

PubMed

Xie, Lei; Draizen, Eli J; Bourne, Philip E

2017-01-06

Systems pharmacology aims to holistically understand mechanisms of drug actions to support drug discovery and clinical practice. Systems pharmacology modeling (SPM) is data driven. It integrates an exponentially growing amount of data at multiple scales (genetic, molecular, cellular, organismal, and environmental). The goal of SPM is to develop mechanistic or predictive multiscale models that are interpretable and actionable. The current explosions in genomics and other omics data, as well as the tremendous advances in big data technologies, have already enabled biologists to generate novel hypotheses and gain new knowledge through computational models of genome-wide, heterogeneous, and dynamic data sets. More work is needed to interpret and predict a drug response phenotype, which is dependent on many known and unknown factors. To gain a comprehensive understanding of drug actions, SPM requires close collaborations between domain experts from diverse fields and integration of heterogeneous models from biophysics, mathematics, statistics, machine learning, and semantic webs. This creates challenges in model management, model integration, model translation, and knowledge integration. In this review, we discuss several emergent issues in SPM and potential solutions using big data technology and analytics. The concurrent development of high-throughput techniques, cloud computing, data science, and the semantic web will likely allow SPM to be findable, accessible, interoperable, reusable, reliable, interpretable, and actionable.

A Mobile Nanoscience and Electron Microscopy Outreach Program

NASA Astrophysics Data System (ADS)

Coffey, Tonya; Kelley, Kyle

2013-03-01

We have established a mobile nanoscience laboratory outreach program in Western NC that puts scanning electron microscopy (SEM) directly in the hands of K-12 students and the general public. There has been a recent push to develop new active learning materials to educate students at all levels about nanoscience and nanotechnology. Previous projects, such as Bugscope, nanoManipulator, or SPM Live! allowed remote access to advanced microscopies. However, placing SEM directly in schools has not often been possible because the cost and steep learning curve of these technologies were prohibitive, making this project quite novel. We have developed new learning modules for a microscopy outreach experience with a tabletop SEM (Hitachi TM3000). We present here an overview of our outreach and results of the assessment of our program to date.

Study of electromechanical and mechanical properties of bacteria using force microscopy

NASA Astrophysics Data System (ADS)

Reukov, Vladimir; Thompson, Gary; Nikiforov, Maxim; Guo, Senli; Ovchinnikov, Oleg; Jesse, Stephen; Kalinin, Sergei; Vertegel, Alexey

2010-03-01

The application of scanning probe microscopy (SPM) to biological systems has evolved over the past decade into a multimodal and spectroscopic instrument that provides multiple information channels at each spatial pixel acquired. Recently, functional recognition imaging based on differing electromechanical properties between Gram negative and Gram positive bacteria was achieved using artificial neural network analysis of band excitation piezoresponse force microscopy (BEPFM) data. The immediate goal of this project was to study mechanical and electromechanical properties of bacterial systems physiologically-relevant solutions using Band-width Excitation Piezoresponce Force Microscopy (BE PFM) in combination with Force Mapping. Electromechanical imaging in physiological environments will improve the versatility of functional recognition imaging and open the way for application of the rapid BEPFM line mode method to other living cell systems.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Siyan; Ding, Jie; Ming, Hongliang

The interface region of welded A508–Alloy 52 M is characterized by scanning probe microscope (SPM) techniques, scanning electron microscopy (SEM)/energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM)/Energy Dispersive Spectroscopy (EDS) and scanning vibrate electrode technique (SVET). The regions along the welded A508–Alloy 52 M interface can be categorized into two types according to their different microstructures. In the type-I interface region, A508 and Alloy 52 M are separated by the fusion boundary, while in the type-II interface region, A508 and Alloy 52 M are separated by a martensite zone. A508, martensite zone and grain boundaries in Alloy 52 M aremore » ferromagnetic while the Alloy 52 M matrix is paramagnetic. The Volta potentials measured by scanning Kelvin probe force microscopy (SKPFM) of A508, martensite zone and Alloy 52 M follow the order: V{sub 52} {sub M} > V{sub A508} > V{sub martensite}. The corrosion behavior of A508–Alloy 52 M interface region is galvanic corrosion, in which Alloy 52 M is cathode while A508 is anode. The martensite dissolves faster than Alloy 52 M, but slower than A508 in the test solution. - Highlights: • The A508–Alloy 52 M interface regions can be categorized into two types. • The chromium depleted region is observed along the Alloy 52 M grain boundary. • The Alloy 52 M grain boundaries which are close to the interface are ferromagnetic. • Martensite zone has lower Volta potential but higher corrosion resistance than A508.« less

Tapping mode SPM local oxidation nanolithography with sub-10 nm resolution

NASA Astrophysics Data System (ADS)

Nishimura, S.; Ogino, T.; Takemura, Y.; Shirakashi, J.

2008-03-01

Tapping mode SPM local oxidation nanolithography with sub-10 nm resolution is investigated by optimizing the applied bias voltage (V), scanning speed (S) and the oscillation amplitude of the cantilever (A). We fabricated Si oxide wires with an average width of 9.8 nm (V = 17.5 V, S = 250 nm/s, A = 292 nm). In SPM local oxidation with tapping mode operation, it is possible to decrease the size of the water meniscus by enhancing the oscillation amplitude of cantilever. Hence, it seems that the water meniscus with sub-10 nm dimensions could be formed by precisely optimizing the oxidation conditions. Moreover, we quantitatively explain the size (width and height) of Si oxide wires with a model based on the oxidation ratio, which is defined as the oxidation time divided by the period of the cantilever oscillation. The model allows us to understand the mechanism of local oxidation in tapping mode operation with amplitude modulation. The results imply that the sub-10 nm resolution could be achieved using tapping mode SPM local oxidation technique with the optimization of the cantilever dynamics.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Henderson, Michael A.; Lyubinetsky, Igor

The field of heterogeneous photocatalysis has grown considerably in the decades since Fujishima and Honda's ground-breaking publications of photoelectrochemistry on TiO2. Numerous review articles continue to point to both progress made in the use of heterogeneous materials (such as TiO2) to perform photoconversion processes, and the many opportunities and challenges in heterogeneous photocatalysis research such as solar energy conversion and environmental remediation. The past decade has also seen an increase in the use of molecular-level approaches applied to model single crystal surfaces in an effort to obtain new insights into photocatalytic phenomena. In particular, scanning probe techniques (SPM) have enabledmore » researchers to take a ‘nanoscale’ approach to photocatalysis that includes interrogation of the reactivities of specific sites and adsorbates on a model photocatalyst surface. The rutile TiO2(110) surface has become the prototypical oxide single crystal surface for fundamental studies of many interfacial phenomena. In particular, TiO2(110) has become an excellent model surface for probing photochemical and photocatalytic reactions at the molecular level. A variety of experimental approaches have emerged as being ideally suited for studying photochemical reactions on TiO2(110), including desorption-oriented approaches and electronic spectroscopies, but perhaps the most promising techniques for evaluating site-specific properties are those of SPM. In this review, we highlight the growing use of SPM techniques in providing molecular-level insights into surface photochemistry on the model photocatalyst surface of rutile TiO2(110). Our objective is to both illustrate the unique knowledge that scanning probe techniques have already provided the field of photocatalysis, and also to motivate a new generation of effort into the use of such approaches to obtain new insights into the molecular level details of photochemical events occurring at interfaces. Discussion will start with an examination of how scanning probe techniques are being used to characterize the TiO2(110) surface in ways that are relevant to photocatalysis. We will then discuss specific classes of photochemical reaction on TiO2(110) for which SPM has proven indispensible in providing unique molecular-level insights, and conclude with discussion of future areas in which SPM studies may prove valuable to photocatalysis on TiO2. This work was supported by the US Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences. I.L. was partially supported by a Pacific Northwest National Laboratory (PNNL) Chemical Imaging Initiative project. PNNL is a multiprogram national laboratory operated for DOE by Battelle.« less

Characterization of Disease-Related Covariance Topographies with SSMPCA Toolbox: Effects of Spatial Normalization and PET Scanners

PubMed Central

Peng, Shichun; Ma, Yilong; Spetsieris, Phoebe G; Mattis, Paul; Feigin, Andrew; Dhawan, Vijay; Eidelberg, David

2013-01-01

In order to generate imaging biomarkers from disease-specific brain networks, we have implemented a general toolbox to rapidly perform scaled subprofile modeling (SSM) based on principal component analysis (PCA) on brain images of patients and normals. This SSMPCA toolbox can define spatial covariance patterns whose expression in individual subjects can discriminate patients from controls or predict behavioral measures. The technique may depend on differences in spatial normalization algorithms and brain imaging systems. We have evaluated the reproducibility of characteristic metabolic patterns generated by SSMPCA in patients with Parkinson's disease (PD). We used [18F]fluorodeoxyglucose PET scans from PD patients and normal controls. Motor-related (PDRP) and cognition-related (PDCP) metabolic patterns were derived from images spatially normalized using four versions of SPM software (spm99, spm2, spm5 and spm8). Differences between these patterns and subject scores were compared across multiple independent groups of patients and control subjects. These patterns and subject scores were highly reproducible with different normalization programs in terms of disease discrimination and cognitive correlation. Subject scores were also comparable in PD patients imaged across multiple PET scanners. Our findings confirm a very high degree of consistency among brain networks and their clinical correlates in PD using images normalized in four different SPM platforms. SSMPCA toolbox can be used reliably for generating disease-specific imaging biomarkers despite the continued evolution of image preprocessing software in the neuroimaging community. Network expressions can be quantified in individual patients independent of different physical characteristics of PET cameras. PMID:23671030

Characterization of disease-related covariance topographies with SSMPCA toolbox: effects of spatial normalization and PET scanners.

PubMed

Peng, Shichun; Ma, Yilong; Spetsieris, Phoebe G; Mattis, Paul; Feigin, Andrew; Dhawan, Vijay; Eidelberg, David

2014-05-01

To generate imaging biomarkers from disease-specific brain networks, we have implemented a general toolbox to rapidly perform scaled subprofile modeling (SSM) based on principal component analysis (PCA) on brain images of patients and normals. This SSMPCA toolbox can define spatial covariance patterns whose expression in individual subjects can discriminate patients from controls or predict behavioral measures. The technique may depend on differences in spatial normalization algorithms and brain imaging systems. We have evaluated the reproducibility of characteristic metabolic patterns generated by SSMPCA in patients with Parkinson's disease (PD). We used [(18) F]fluorodeoxyglucose PET scans from patients with PD and normal controls. Motor-related (PDRP) and cognition-related (PDCP) metabolic patterns were derived from images spatially normalized using four versions of SPM software (spm99, spm2, spm5, and spm8). Differences between these patterns and subject scores were compared across multiple independent groups of patients and control subjects. These patterns and subject scores were highly reproducible with different normalization programs in terms of disease discrimination and cognitive correlation. Subject scores were also comparable in patients with PD imaged across multiple PET scanners. Our findings confirm a very high degree of consistency among brain networks and their clinical correlates in PD using images normalized in four different SPM platforms. SSMPCA toolbox can be used reliably for generating disease-specific imaging biomarkers despite the continued evolution of image preprocessing software in the neuroimaging community. Network expressions can be quantified in individual patients independent of different physical characteristics of PET cameras. Copyright © 2013 Wiley Periodicals, Inc.

Design and evaluation of precise current integrator for scanning probe microscopy

NASA Astrophysics Data System (ADS)

Raczkowski, Kamil; Piasecki, Tomasz; Rudek, Maciej; Gotszalk, Teodor

2017-03-01

Several of the scanning probe microscopy (SPM) techniques, such as the scanning tunnelling microscopy (STM) or conductive atomic force microscopy (C-AFM), rely on precise measurements of current flowing between the investigated sample and the conductive nanoprobe. The parameters of current-to-voltage converter (CVC), which should detect current in the picompere range, are of utmost importance to those systems as they determine the microscopes’ measuring capabilities. That was the motivation for research on the precise current integrator (PCI), described in this paper, which could be used as the CVC in the C-AFM systems. The main design goal of the PCI was to provide a small and versatile device with the sub-picoampere level resolution with high dynamic range in the order of nanoamperes. The PCI was based on the integrating amplifier (Texas Instruments DDC112) paired with a STM32F4 microcontroller unit (MCU).The gain and bandwidth of the PCI might be easily changed by varying the integration time and the feedback capacitance. Depending on these parameters it was possible to obtain for example the 2.15 pA resolution at 688 nA range with 1 kHz bandwidth or 7.4 fA resolution at 0.98 nA range with 10 Hz bandwidth. The measurement of sinusoidal current with 28 fA amplitude was also presented. The PCI was integrated with the C-AFM system and used in the highly ordered pyrolytic graphite (HOPG) and graphene samples imaging.

Oligodeoxyribonucleotide association with single-walled carbon nanotubes studied by SPM.

PubMed

Lahiji, Roya R; Dolash, Bridget D; Bergstrom, Donald E; Reifenberger, Ronald

2007-11-01

Studies have been performed on both as-received and chemically oxidized single-walled carbon nanotubes (SWCNTs) grown by two different growth methods to better understand the preferential association of the oligodeoxyribonucleotide T30 (ODN) with SWCNTs. Samples of T30 ODN:SWCNT were examined under ambient conditions using non-contact scanning probe microscope (SPM) techniques. The resulting images show different morphologies ranging from tangled networks of SWCNTs to individual, well-dispersed isolated SWCNTs as the sonication time is increased. SPM images of well-dispersed, as-received SWCNTs reveal isolated features that are 1.4 to 2.8 nm higher than the bare SWCNT itself. X-ray photoemission spectroscopy (XPS) confirmed these features to be T30 ODN in nature. Chemically oxidizing the SWCNTs before sonication is found to be an effective way to increase the number of T30 ODN features.

SPM local oxidation nanolithography with active control of cantilever dynamics

NASA Astrophysics Data System (ADS)

Nishimura, S.; Takemura, Y.; Shirakashi, J.

2007-04-01

Local oxidation nanolithography using scanning probe microscope (SPM) has enabled us to fabricate nanometer-scale oxide wires on material surfaces. Here, we study tapping mode SPM local oxidation experiments for silicon by controlling the dynamic properties of the cantilever. Dependence of feature size of fabricated oxide wires on the amplitude of the cantilever was precisely investigated. The quality factor (Q) was fixed at a natural value of ~500. By enhancing the amplitude of the cantilever, both width and height of fabricated Si oxide wires were decreased. With the variation of the amplitude of the cantilever from 0.5 V to 3.0 V (DC voltage = 22.5 V, scanning speed = 20 nm/s), the feature size of Si oxide wires was well controlled, ranging from 40 nm to 18 nm in width and 2.3 nm to 0.6 nm in height. Standard deviation of width on Si oxide wires formed by tapping mode SPM is around 2.0 nm, which is smaller than that of contact mode Si oxide wires. Furthermore, the variation of the oscillation amplitude of the cantilever does not affect the size uniformity of the wires. These results imply that the SPM local oxidation nanolithography with active control of cantilever dynamics is a useful technique for producing higher controllability on the nanometer-scale fabrication of Si oxide wires.

Micromagnet arrays for on-chip focusing, switching, and separation of superparamagnetic beads and single cells.

PubMed

Rampini, S; Kilinc, D; Li, P; Monteil, C; Gandhi, D; Lee, G U

2015-08-21

Nonlinear magnetophoresis (NLM) is a novel approach for on-chip transport and separation of superparamagnetic (SPM) beads, based on a travelling magnetic field wave generated by the combination of a micromagnet array (MMA) and an applied rotating magnetic field. Here, we present two novel MMA designs that allow SPM beads to be focused, sorted, and separated on-chip. Converging MMAs were used to rapidly collect the SPM beads from a large region of the chip and focus them into synchronised lines. We characterise the collection efficiency of the devices and demonstrate that they can facilitate on-chip analysis of populations of SPM beads using a single-point optical detector. The diverging MMAs were used to control the transport of the beads and to separate them based on their size. The separation efficiency of these devices was determined by the orientation of the magnetisation of the micromagnets relative to the external magnetic field and the size of the beads and relative to that of micromagnets. By controlling these parameters and the rotation of the external magnetic field we demonstrated the controlled transport of SPM bead-labelled single MDA-MB-231 cells. The use of these novel MMAs promises to allow magnetically-labelled cells to be efficiently isolated and then manipulated on-chip for analysis with high-resolution chemical and physical techniques.

Scanning Probe Microscopy for Identifying the Component Materials of a Nanostripe Structure

NASA Astrophysics Data System (ADS)

Mizuno, Akira; Ando, Yasuhisa

2010-08-01

The authors prepared a nanostripe structure in which two types of metal are arranged alternately, and successfully identified the component materials using scanning probe microscopy (SPM) to measure the lateral force distribution image. The nanostripe structure was prepared using a new method developed by the authors and joint development members. The lateral force distribution image was measured in both friction force microscopy (FFM) and lateral modulation friction force microscopy (LM-FFM) modes. In FFM mode, the effect of slope angle appeared in the lateral force distribution image; therefore, no difference in the type of material was observed. On the other hand, in LM-FFM mode, the effect of surface curvature was observed in the lateral force distribution image. A higher friction force on chromium than on gold was identified, enabling material identification.

Self-assembled polystyrene nanospheres for the evaluation of atomic force microscopy tip curvature radius

NASA Astrophysics Data System (ADS)

Colombi, P.; Alessandri, I.; Bergese, P.; Federici, S.; Depero, L. E.

2009-08-01

In this paper, self-assembled polystyrene nanospheres are proposed as a shape characterizer sample for SPM tips. Ordered arrays or 2D islands of polystyrene spheres may be prepared either by sedimentation or by crystallization of the colloidal spheres' suspension. The self-assembling mechanism guarantees high reproducibility; thus the characterizer sample can be 'freshly' prepared at each use, avoiding the problem of time and use deterioration and reducing the problem of sample structure fidelity that occurs when lithographic structures are employed. The spheres could also be deposited on the sample itself in order to speed up the characterization process in applications requiring frequent tip characterizations. We present numerical calculations of geometrical convoluted profiles on the proposed structures showing that, for a variety of different tip shapes, at the border between a couple of touching spheres the tip flanks do not come into contact with the spheres. Due to this behaviour, touching spheres are an optimum characterizer sample for SPM tip curvature radius characterization, enabling a straightforward procedure for calculating the curvature radius from the amplitude of tip oscillation along profiles connecting spheres' centres. The new procedure for the characterization of SPM probes was assessed exploiting different kinds of self-assembled structures and comparing results to those obtained by spiked structures and SEM observations.

A review of oil-suspended particulate matter aggregation--a natural process of cleansing spilled oil in the aquatic environment.

PubMed

Sun, Juan; Zheng, Xilai

2009-10-01

It has been acknowledged that following an oil spill in coastal areas where suspended particulate matter (SPM) is rich, aggregation between oil and SPM can be naturally formed. This kind of aggregation product is termed as oil-SPM aggregates (OSAs). Because OSAs are not as sticky to the shorelines as crude oil and the oil-water contact area is greatly increased due to the formation of OSAs, both oil dispersion into the water body and oil biodegration would be significantly enhanced. In this review article, the authors (1) describe in detail the mechanism of OSA formation and controlling parameters which can influence OSA formation (the parameters discussed include the oil nature and properties, sediment types and concentrations, and the environmental factors such as salinity, temperature and mixing energy); (2) briefly review qualitative and quantitative methods used for characterization of OSA formation (two main methods used for the OSA characterization are the UV epi-fluorescence microscopy and gas chromatography equipped with flame ionization detector (GC-FID); (3) elucidate the applications of OSA formation in oil spill response strategies including natural attenuation, sediment relocation, and sediment mixing; and (4) discuss research needs in the future which would further improve our understanding of OSA formation and move towards the development of adequate oil behaviour models.

Self-Cooling Gradient Shell for Body Armor

DTIC Science & Technology

2012-05-10

Silica gel 2.1 Filter paper pocket (no absorbent) 2.0 2 g Silica gel (150-Å pore size) + 2 g sodium polyacrylate (SPA) in filter paper pocket 2.7...layer of filter paper improved the temperature difference by an additional 0.5 °C. More-absorbent materials, such as sodium polyacrylate (SPA) or... sodium polyacrylate SPM scanning probe microscopy µm micrometer Wm-2 watts per square meter °C degrees Celsius

Comparison between KPVT/SPM and SoHO/MDI magnetograms with an application to solar irradiance reconstructions

NASA Astrophysics Data System (ADS)

Wenzler, T.; Solanki, S. K.; Krivova, N. A.; Fluri, D. M.

2004-12-01

To be able to use both space- and ground-based solar magnetograms and construct long time series of derived parameters it is important to cross-calibrate them so that we can estimate their reliability and combine them. Using two different techniques, we compare magnetograms as well as continuum images recorded by the Spectropolarimeter (SPM) on Kitt Peak and the Michelson Doppler Interferometer (MDI) on board SoHO. We find that the result obtained depends on the method used. The method we favour gives almost identical umbral and penumbral areas and very similar total magnetic fluxes in faculae. The magnetic fluxes in umbrae and penumbrae returned by the two instruments, however, differ considerably. We also demonstrate that SPM data can be employed to reconstruct total solar irradiance variations with almost the same accuracy as recently shown for MDI data.

PALS and SPM/EFM investigation of charged nanoporous electret films

NASA Astrophysics Data System (ADS)

Chiang, Dar-Ming; Liu, Wen-Liang; Chen, Jen-Luan; Susuki, Ryoichi

2005-08-01

The electret properties of nanoporous Teflon-FEP films, fabricated by the super-critical fluids method and charged by the corona method at room temperature, are investigated. PALS and SAXS are applied first to examine the charge characteristics of a free volume of electret materials. The topography and surface charges of electret materials are determined by scanning probe microscopy and electric field microscopy, respectively. The experimental results reveal that the interior surface areas of the pores of the electret materials influence the retention and stability of charge. Initial and aged surface charge was increased by factors of two and ten, with and without nanoporous Teflon-FEP films, respectively.

The second iteration of the Systems Prioritization Method: A systems prioritization and decision-aiding tool for the Waste Isolation Pilot Plant: Volume 2, Summary of technical input and model implementation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prindle, N.H.; Mendenhall, F.T.; Trauth, K.

1996-05-01

The Systems Prioritization Method (SPM) is a decision-aiding tool developed by Sandia National Laboratories (SNL). SPM provides an analytical basis for supporting programmatic decisions for the Waste Isolation Pilot Plant (WIPP) to meet selected portions of the applicable US EPA long-term performance regulations. The first iteration of SPM (SPM-1), the prototype for SPM< was completed in 1994. It served as a benchmark and a test bed for developing the tools needed for the second iteration of SPM (SPM-2). SPM-2, completed in 1995, is intended for programmatic decision making. This is Volume II of the three-volume final report of the secondmore » iteration of the SPM. It describes the technical input and model implementation for SPM-2, and presents the SPM-2 technical baseline and the activities, activity outcomes, outcome probabilities, and the input parameters for SPM-2 analysis.« less

Surface plasmon holographic microscopy for near-field refractive index detection and thin film mapping

NASA Astrophysics Data System (ADS)

Zhao, Jianlin; Zhang, Jiwei; Dai, Siqing; Di, Jianglei; Xi, Teli

2018-02-01

Surface plasmon microscopy (SPM) is widely applied for label-free detection of changes of refractive index and concentration, as well as mapping thin films in near field. Traditionally, the SPM systems are based on the detection of light intensity or phase changes. Here, we present two kinds of surface plasmon holographic microscopy (SPHM) systems for amplitude- and phase-contrast imaging simultaneously. Through recording off-axis holograms and numerical reconstruction, the complex amplitude distributions of surface plasmon resonance (SPR) images can be obtained. According to the Fresnel's formula, in a prism/ gold/ dielectric structure, the reflection phase shift is uniquely decided by refractive index of the dielectric. By measuring the phase shift difference of the reflected light exploiting prism-coupling SPHM system based on common-path interference configuration, monitoring tiny refractive index variation and imaging biological tissue are performed. Furthermore, to characterize the thin film thickness in near field, we employ a four-layer SPR model in which the third film layer is within the evanescent field. The complex reflection coefficient, including the reflectivity and reflection phase shift, is uniquely decided by the film thickness. By measuring the complex amplitude distributions of the SPR images exploiting objective-coupling SPHM system based on common-path interference configuration, the thickness distributions of thin films are mapped with sub-nanometer resolution theoretically. Owing to its high temporal stability, the recommended SPHMs show great potentials for monitoring tiny refractive index variations, imaging biological tissues and mapping thin films in near field with dynamic, nondestructive and full-field measurement capabilities in chemistry, biomedicine field, etc.

A study approach on ferroelectric domains in BaTiO{sub 3}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rocha, L.S.R.; Cavalcanti, C.S.

Atomic Force Acoustic Microscopy (AFAM) and Piezoresponse Force Microscopy (PFM) were used to study local elastic and electromechanical response in BaTiO{sub 3} ceramics. A commercial multi-mode Scanning Probe Microscopy (SPM) and AFAM mode to image contact stiffness were employed to accomplish the aforementioned purposes. Stiffness parameters along with Young's moduli and piezo coefficients were quantitatively determined. PFM studies were based on electrostatic and electromechanical response from localized tip-surface contact. Comparison was made regarding the Young's moduli obtained by AFAM and PFM. In addition, phase and amplitude images were analyzed based on poling behavior, obtained via the application of − 10more » V to + 10 V local voltage. - Highlights: •Nanoscale behavior of piezo domains in BaTiO{sub 3} ferroelectric materials •Use of Atomic Force Acoustic Microscopy (AFAM) and Piezo Force Microscopy (PFM) •Local elastic and electromechanical response in BaTiO{sub 3} ceramics •The young's moduli obtained from AFAM and PFM.« less

A versatile LabVIEW and field-programmable gate array-based scanning probe microscope for in operando electronic device characterization.

PubMed

Berger, Andrew J; Page, Michael R; Jacob, Jan; Young, Justin R; Lewis, Jim; Wenzel, Lothar; Bhallamudi, Vidya P; Johnston-Halperin, Ezekiel; Pelekhov, Denis V; Hammel, P Chris

2014-12-01

Understanding the complex properties of electronic and spintronic devices at the micro- and nano-scale is a topic of intense current interest as it becomes increasingly important for scientific progress and technological applications. In operando characterization of such devices by scanning probe techniques is particularly well-suited for the microscopic study of these properties. We have developed a scanning probe microscope (SPM) which is capable of both standard force imaging (atomic, magnetic, electrostatic) and simultaneous electrical transport measurements. We utilize flexible and inexpensive FPGA (field-programmable gate array) hardware and a custom software framework developed in National Instrument's LabVIEW environment to perform the various aspects of microscope operation and device measurement. The FPGA-based approach enables sensitive, real-time cantilever frequency-shift detection. Using this system, we demonstrate electrostatic force microscopy of an electrically biased graphene field-effect transistor device. The combination of SPM and electrical transport also enables imaging of the transport response to a localized perturbation provided by the scanned cantilever tip. Facilitated by the broad presence of LabVIEW in the experimental sciences and the openness of our software solution, our system permits a wide variety of combined scanning and transport measurements by providing standardized interfaces and flexible access to all aspects of a measurement (input and output signals, and processed data). Our system also enables precise control of timing (synchronization of scanning and transport operations) and implementation of sophisticated feedback protocols, and thus should be broadly interesting and useful to practitioners in the field.

A versatile LabVIEW and field-programmable gate array-based scanning probe microscope for in operando electronic device characterization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berger, Andrew J., E-mail: berger.156@osu.edu; Page, Michael R.; Young, Justin R.

Understanding the complex properties of electronic and spintronic devices at the micro- and nano-scale is a topic of intense current interest as it becomes increasingly important for scientific progress and technological applications. In operando characterization of such devices by scanning probe techniques is particularly well-suited for the microscopic study of these properties. We have developed a scanning probe microscope (SPM) which is capable of both standard force imaging (atomic, magnetic, electrostatic) and simultaneous electrical transport measurements. We utilize flexible and inexpensive FPGA (field-programmable gate array) hardware and a custom software framework developed in National Instrument's LabVIEW environment to perform themore » various aspects of microscope operation and device measurement. The FPGA-based approach enables sensitive, real-time cantilever frequency-shift detection. Using this system, we demonstrate electrostatic force microscopy of an electrically biased graphene field-effect transistor device. The combination of SPM and electrical transport also enables imaging of the transport response to a localized perturbation provided by the scanned cantilever tip. Facilitated by the broad presence of LabVIEW in the experimental sciences and the openness of our software solution, our system permits a wide variety of combined scanning and transport measurements by providing standardized interfaces and flexible access to all aspects of a measurement (input and output signals, and processed data). Our system also enables precise control of timing (synchronization of scanning and transport operations) and implementation of sophisticated feedback protocols, and thus should be broadly interesting and useful to practitioners in the field.« less

Post traumatic brain perfusion SPECT analysis using reconstructed ROI maps of radioactive microsphere derived cerebral blood flow and statistical parametric mapping

PubMed Central

McGoron, Anthony J; Capille, Michael; Georgiou, Michael F; Sanchez, Pablo; Solano, Juan; Gonzalez-Brito, Manuel; Kuluz, John W

2008-01-01

Background Assessment of cerebral blood flow (CBF) by SPECT could be important in the management of patients with severe traumatic brain injury (TBI) because changes in regional CBF can affect outcome by promoting edema formation and intracranial pressure elevation (with cerebral hyperemia), or by causing secondary ischemic injury including post-traumatic stroke. The purpose of this study was to establish an improved method for evaluating regional CBF changes after TBI in piglets. Methods The focal effects of moderate traumatic brain injury (TBI) on cerebral blood flow (CBF) by SPECT cerebral blood perfusion (CBP) imaging in an animal model were investigated by parallelized statistical techniques. Regional CBF was measured by radioactive microspheres and by SPECT 2 hours after injury in sham-operated piglets versus those receiving severe TBI by fluid-percussion injury to the left parietal lobe. Qualitative SPECT CBP accuracy was assessed against reference radioactive microsphere regional CBF measurements by map reconstruction, registration and smoothing. Cerebral hypoperfusion in the test group was identified at the voxel level using statistical parametric mapping (SPM). Results A significant area of hypoperfusion (P < 0.01) was found as a response to the TBI. Statistical mapping of the reference microsphere CBF data confirms a focal decrease found with SPECT and SPM. Conclusion The suitability of SPM for application to the experimental model and ability to provide insight into CBF changes in response to traumatic injury was validated by the SPECT SPM result of a decrease in CBP at the left parietal region injury area of the test group. Further study and correlation of this characteristic lesion with long-term outcomes and auxiliary diagnostic modalities is critical to developing more effective critical care treatment guidelines and automated medical imaging processing techniques. PMID:18312639

Post traumatic brain perfusion SPECT analysis using reconstructed ROI maps of radioactive microsphere derived cerebral blood flow and statistical parametric mapping.

PubMed

McGoron, Anthony J; Capille, Michael; Georgiou, Michael F; Sanchez, Pablo; Solano, Juan; Gonzalez-Brito, Manuel; Kuluz, John W

2008-02-29

Assessment of cerebral blood flow (CBF) by SPECT could be important in the management of patients with severe traumatic brain injury (TBI) because changes in regional CBF can affect outcome by promoting edema formation and intracranial pressure elevation (with cerebral hyperemia), or by causing secondary ischemic injury including post-traumatic stroke. The purpose of this study was to establish an improved method for evaluating regional CBF changes after TBI in piglets. The focal effects of moderate traumatic brain injury (TBI) on cerebral blood flow (CBF) by SPECT cerebral blood perfusion (CBP) imaging in an animal model were investigated by parallelized statistical techniques. Regional CBF was measured by radioactive microspheres and by SPECT 2 hours after injury in sham-operated piglets versus those receiving severe TBI by fluid-percussion injury to the left parietal lobe. Qualitative SPECT CBP accuracy was assessed against reference radioactive microsphere regional CBF measurements by map reconstruction, registration and smoothing. Cerebral hypoperfusion in the test group was identified at the voxel level using statistical parametric mapping (SPM). A significant area of hypoperfusion (P < 0.01) was found as a response to the TBI. Statistical mapping of the reference microsphere CBF data confirms a focal decrease found with SPECT and SPM. The suitability of SPM for application to the experimental model and ability to provide insight into CBF changes in response to traumatic injury was validated by the SPECT SPM result of a decrease in CBP at the left parietal region injury area of the test group. Further study and correlation of this characteristic lesion with long-term outcomes and auxiliary diagnostic modalities is critical to developing more effective critical care treatment guidelines and automated medical imaging processing techniques.

A new systematic and quantitative approach to characterization of surface nanostructures using fuzzy logic

NASA Astrophysics Data System (ADS)

Al-Mousa, Amjed A.

Thin films are essential constituents of modern electronic devices and have a multitude of applications in such devices. The impact of the surface morphology of thin films on the device characteristics where these films are used has generated substantial attention to advanced film characterization techniques. In this work, we present a new approach to characterize surface nanostructures of thin films by focusing on isolating nanostructures and extracting quantitative information, such as the shape and size of the structures. This methodology is applicable to any Scanning Probe Microscopy (SPM) data, such as Atomic Force Microscopy (AFM) data which we are presenting here. The methodology starts by compensating the AFM data for some specific classes of measurement artifacts. After that, the methodology employs two distinct techniques. The first, which we call the overlay technique, proceeds by systematically processing the raster data that constitute the scanning probe image in both vertical and horizontal directions. It then proceeds by classifying points in each direction separately. Finally, the results from both the horizontal and the vertical subsets are overlaid, where a final decision on each surface point is made. The second technique, based on fuzzy logic, relies on a Fuzzy Inference Engine (FIE) to classify the surface points. Once classified, these points are clustered into surface structures. The latter technique also includes a mechanism which can consistently distinguish crowded surfaces from those with sparsely distributed structures and then tune the fuzzy technique system uniquely for that surface. Both techniques have been applied to characterize organic semiconductor thin films of pentacene on different substrates. Also, we present a case study to demonstrate the effectiveness of our methodology to identify quantitatively particle sizes of two specimens of gold nanoparticles of different nominal dimensions dispersed on a mica surface. A comparison with other techniques like: thresholding, watershed and edge detection is presented next. Finally, we present a systematic study of the fuzzy logic technique by experimenting with synthetic data. These results are discussed and compared along with the challenges of the two techniques.

Imaging Electron Motion in a Few Layer MoS2 Device

NASA Astrophysics Data System (ADS)

Bhandari, S.; Wang, K.; Watanabe, K.; Taniguchi, T.; Kim, P.; Westervelt, R. M.

2017-06-01

Ultrathin sheets of MoS2 are a newly discovered 2D semiconductor that holds great promise for nanoelectronics. Understanding the pattern of current flow will be crucial for developing devices. In this talk, we present images of current flow in MoS2 obtained with a Scanned Probe Microscope (SPM) cooled to 4 K. We previously used this technique to image electron trajectories in GaAs/AlGaAs heterostructures and graphene. The charged SPM tip is held just above the sample surface, creating an image charge inside the device that scatters electrons. By measuring the change in resistance ΔR while the tip is raster scanned above the sample, an image of electron flow is obtained. We present images of electron flow in an MoS2 device patterned into a hall bar geometry. A three-layer MoS2 sheet is encased by two hBN layers, top and bottom, and patterned into a hall-bar with multilayer graphene contacts. An SPM image shows the current flow pattern from the wide contact at the end of the device for a Hall density n = 1.3×1012 cm-2. The SPM tip tends to block flow, increasing the resistance R. The pattern of flow was also imaged for a narrow side contact on the sample. At density n = 5.4×1011 cm-2; the pattern seen in the SPM image is similar to the wide contact. The ability to image electron flow promises to be very useful for the development of ultrathin devices from new 2D materials.

Potential for heavy metal (copper and zinc) removal from contaminated marine sediments using microalgae and light emitting diodes

NASA Astrophysics Data System (ADS)

Kwon, Hyeong Kyu; Jeon, Jin Young; Oh, Seok Jin

2017-03-01

The effects of monochromatic (blue, yellow and red LED) and mixed wavelengths (fluorescent lamp) on the adsorption and absorption of Cu and Zn by Phaeodactylum tricornutum, Nitzschia sp., Skeletonema sp., and Chlorella vulgaris were investigated. In addition, we confirmed the potential of microalgae for phytoremediation of these heavy metals from contaminated marine sediment by using microcosm experiments that incorporated LEDs and semipermeable membrane (SPM) tube containing microalgae. Among the four microalgae, C. vulgaris grown under red LED exhibited the highest Cu and Zn removal with values of 17.5 × 10-15 g Cu/cell and 38.3 × 10-15 g Zn/cell, respectively. Thus, C. vulgaris could be a useful species for phytoremediation. In the microcosm experiments with SPM containing C. vulgaris, the highest Cu and Zn removal from sediment and interstitial water showed under red LED. Therefore, phytoremediation using LED and SPM tube containing microalgae could be utilized as an eco-friendly technique for remediating contaminated marine sediment.

Microscale localization and isolation of light emitting imperfections in monocrystalline silicon solar cells

NASA Astrophysics Data System (ADS)

Gajdoš, Adam; Škvarenina, Lubomír.; Škarvada, Pavel; Macků, Robert

2017-12-01

An imperfections or defects may appear in fabricated monocrystalline solar cells. These microstructural imperfections could have impact on the parameters of whole solar cell. The research is divided into two parts, firstly, the detection and localization defects by using several techniques including current-voltage measurement, scanning probe microscopy (SPM), scanning electron microscope (SEM) and electroluminescence. Secondly, the defects isolation by a focused ion beam (FIB) milling and impact of a milling process on solar cells. The defect detection is realized by I-V measurement under reverse biased sample. For purpose of localization, advantage of the fact that defects or imperfections in silicon solar cells emit the visible and near infrared electroluminescence under reverse biased voltage is taken, and CCD camera measurement for macroscopic localization of these spots is applied. After rough macroscopic localization, microscopic localization by scanning probe microscopy combined with a photomultiplier (shadow mapping) is performed. Defect isolation is performed by a SEM equipped with the FIB instrument. FIB uses a beam of gallium ions which modifies crystal structure of a material and may affect parameters of solar cell. As a result, it is interesting that current in reverse biased sample with isolated defect is smaller approximately by 2 orders than current before isolation process.

Characterisation of urban catchment suspended particulate matter (Auckland region, New Zealand); a comparison with non-urban SPM.

PubMed

Bibby, Rebecca L; Webster-Brown, Jenny G

2005-05-01

Suspended particulate matter (SPM) is an important transport agent for metal contaminants in streams, particularly during high flow periods such as storm events. For highly contaminated urban catchments in the greater Auckland (New Zealand) area, trace metal partitioning between the dissolved phase and SPM was determined, and SPM characterised in terms of its Si, Al, Fe, Mn, Zn, Cu, Pb, TOC, TON and PO(4) concentrations, as well as particle size, abundance, type and surface area. This data was compared to similar data from representative non-urban catchments in the Auckland region, the Kaipara River and Waikato River catchments, to identify any significant differences in the SPM and its potential trace metal adsorption capacity. Trace metal partitioning was assessed by way of a distribution coefficient: K(D)=[Me(SPM)]/[Me(DISS)]. Auckland urban SPM comprises quartz, feldspars and clay minerals, with Fe-oxides and minor Mn-oxides. No particles of anthropogenic origin, other than glass shards, were observed. No change in urban SPM particle size or SSA was observed with seasonal change in temperature, but the nature of the SPM was observed to change with flow regime. The abundance of finer particles, SSA and Al content of the SPM increased under moderate flow conditions; however, Si/Al ratios remained constant, confirming the importance of aluminosilicate detrital minerals in surface run-off. The SPM Fe content was observed to decrease with increased flow and was attributed to dilution of SPM Fe-oxide of groundwater origin. The Kaipara River SPM was found to be mineralogically, chemically and biologically similar to the urban SPM. However, major differences between urban catchment SPM and SPM from the much larger (non-urban) Waikato River were observed, and attributed to a higher abundance of diatoms. The Fe content of the Waikato River SPM was consistently lower (<5%), and the Si/Al ratio and Mn content was higher. Such differences observed between urban and non-urban SPM did not appear to affect the partitioning of Zn and Cu; however, Pb in the Kaipara and Waikato Rivers was found to be more associated with the dissolved phase. This is likely to reflect higher particulate Pb inputs to urban systems.

Using the Medipix3 detector for direct electron imaging in the range 60 keV to 200 keV in electron microscopy

NASA Astrophysics Data System (ADS)

Mir, J. A.; Plackett, R.; Shipsey, I.; dos Santos, J. M. F.

2017-11-01

Hybrid pixel sensor technology such as the Medipix3 represents a unique tool for electron imaging. We have investigated its performance as a direct imaging detector using a Transmission Electron Microscope (TEM) which incorporated a Medipix3 detector with a 300 μm thick silicon layer compromising of 256×256 pixels at 55 μm pixel pitch. We present results taken with the Medipix3 in Single Pixel Mode (SPM) with electron beam energies in the range, 60-200 keV . Measurements of the Modulation Transfer Function (MTF) and the Detective Quantum Efficiency (DQE) were investigated. At a given beam energy, the MTF data was acquired by deploying the established knife edge technique. Similarly, the experimental data required to determine DQE was obtained by acquiring a stack of images of a focused beam and of free space (flatfield) to determine the Noise Power Spectrum (NPS).

Characteristic Behavior and Scaling Studies of Self Organized InP Nano-dots formed via keV and MeV irradiations

NASA Astrophysics Data System (ADS)

Paramanik, Dipak; Varma, Shikha

2008-04-01

The controlled formation of nano-dots, using ion beams as tool, has become important as it offers a unique method to generate non-equilibrium phases with novel physical properties and structures with nano-dimensions. We have investigated the creation of self assembled nano- dots on InP(111) surfaces after 3 keV as well as 1.5 MeV ion beams at a large range of fluences. We have studied the Scaling exponents of the evolved surfaces by utilizing the technique of Scanning Probe Microscopy (SPM). At keV energies ripening of the nano-dots is seen below a critical time whereas an inverse ripening is observed for longer durations. At the critical time square shaped array of nano --dots are observed. The dots are characterized by narrow height and size distributions. Nano dots have also been observed at MeV ion irradiations. Their size distribution though broad at lowest fluence decreases for larger fluences.

Mobility of the maize suppressor-mutator element in transgenic tobacco cells.

PubMed Central

Masson, P; Fedoroff, N V

1989-01-01

Maize Suppressor-mutator (Spm) transposable elements have been introduced into tobacco cells and a visual assay for Spm activity has been developed using a bacterial beta-glucuronidase gene. The Spm element is mobile in tobacco and can trans-activate excision of a transposition-defective Spm (dSpm) element either from a different site on the same transforming Ti plasmid or from a second plasmid. An Spm element expressed from the stronger cauliflower mosaic virus 35S promoter trans-activates transposition of a dSpm element earlier after its introduction into tobacco cells than an element expressed from its own promoter. Images PMID:2538837

Multi Length Scale Imaging of Flocculated Estuarine Sediments; Insights into their Complex 3D Structure

NASA Astrophysics Data System (ADS)

Wheatland, Jonathan; Bushby, Andy; Droppo, Ian; Carr, Simon; Spencer, Kate

2015-04-01

Suspended estuarine sediments form flocs that are compositionally complex, fragile and irregularly shaped. The fate and transport of suspended particulate matter (SPM) is determined by the size, shape, density, porosity and stability of these flocs and prediction of SPM transport requires accurate measurements of these three-dimensional (3D) physical properties. However, the multi-scaled nature of flocs in addition to their fragility makes their characterisation in 3D problematic. Correlative microscopy is a strategy involving the spatial registration of information collected at different scales using several imaging modalities. Previously, conventional optical microscopy (COM) and transmission electron microscopy (TEM) have enabled 2-dimensional (2D) floc characterisation at the gross (> 1 µm) and sub-micron scales respectively. Whilst this has proven insightful there remains a critical spatial and dimensional gap preventing the accurate measurement of geometric properties and an understanding of how structures at different scales are related. Within life sciences volumetric imaging techniques such as 3D micro-computed tomography (3D µCT) and focused ion beam scanning electron microscopy [FIB-SEM (or FIB-tomography)] have been combined to characterise materials at the centimetre to micron scale. Combining these techniques with TEM enables an advanced correlative study, allowing material properties across multiple spatial and dimensional scales to be visualised. The aims of this study are; 1) to formulate an advanced correlative imaging strategy combining 3D µCT, FIB-tomography and TEM; 2) to acquire 3D datasets; 3) to produce a model allowing their co-visualisation; 4) to interpret 3D floc structure. To reduce the chance of structural alterations during analysis samples were first 'fixed' in 2.5% glutaraldehyde/2% formaldehyde before being embedding in Durcupan resin. Intermediate steps were implemented to improve contrast and remove pore water, achieved by the addition of heavy metal stains and washing samples in a series of ethanol solutions and acetone. Gross-scale characterisation involved scanning samples using a Nikon Metrology HM X 225 µCT. For micro-scale analysis a working surface was revealed by microtoming the sample. Ultrathin sections were then collected and analysed using a JEOL 1200 Ex II TEM, and FIB-tomography datasets obtained using an FEI Quanta 3D FIB-SEM. Finally, to locate the surface and relate TEM and FIB-tomography datasets to the original floc, samples were rescanned using the µCT. Image processing was initially conducted in ImageJ. Following this datasets were imported into Amira 5.5 where pixel intensity thresholding allowed particle-matrix boundaries to be defined. Using 'landmarks' datasets were then registered to enable their co-visualisation in 3D models. Analysis of registered datasets reveals the complex non-fractal nature of flocs, whose properties span several of orders of magnitude. Primary particles are organised into discrete 'bundles', the arrangement of which directly influences their gross morphology. This strategy, which allows the co-visualisation of spatially registered multi-scale 3D datasets, provides unique insights into the true nature floc which would other have been impossible.

Empirical Guidelines for Use of Irregular Wave Model to Estimate Nearshore Wave Height.

DTIC Science & Technology

1982-07-01

height, the easier to use tech- nique presented by McClenan (1975) was employed. The McClenan technique uti- lizes a monogram which was constructed from...the SPM equations and gives the same results. The inputs to the monogram technique are the period, the deep- water wave height, the deepwater wave

Spm1, a stress-activated MAP kinase that regulates morphogenesis in S.pombe.

PubMed Central

Zaitsevskaya-Carter, T; Cooper, J A

1997-01-01

A gene encoding a novel MAP kinase family member, Spm1, was isolated from the fission yeast Schizosaccharomyces pombe. Overproduction of Spm1 inhibits proliferation. Disruption of the spm1+ gene interferes with cell separation and morphogenesis. Under conditions of nutrient limitation, hypertonic stress or elevated temperature, spm1 delta cells grow as short branched filaments in which the cell walls and septa are thickened, suggesting defects in polarized growth and cell wall remodeling. At high osmolarity, spm1 delta cells fail to form colonies. The Spm1 protein is tyrosine phosphorylated and activated in response to osmotic and heat stress, consistent with a role for Spm1 in adaptation to these conditions. Two other S.pombe MAP kinases are known, Spk1, required for sexual differentiation and sporulation, and Spc1/Sty1/Phh1, which is activated in hypertonic conditions. However, the distinctive features of the spm1 delta mutant phenotype and direct biochemical assays suggest that Spm1 does not lie on other known MAP kinase pathways. Our results demonstrate the existence of a new MAP kinase pathway that regulates cell wall remodeling and cytokinesis in response to environmental stresses. PMID:9135147

Quantifying uncertainty in measurement of mercury in suspended particulate matter by cold vapor technique using atomic absorption spectrometry with hydride generator.

PubMed

Singh, Nahar; Ahuja, Tarushee; Ojha, Vijay Narain; Soni, Daya; Tripathy, S Swarupa; Leito, Ivo

2013-01-01

As a result of rapid industrialization several chemical forms of organic and inorganic mercury are constantly introduced to the environment and affect humans and animals directly. All forms of mercury have toxic effects; therefore accurate measurement of mercury is of prime importance especially in suspended particulate matter (SPM) collected through high volume sampler (HVS). In the quantification of mercury in SPM samples several steps are involved from sampling to final result. The quality, reliability and confidence level of the analyzed data depends upon the measurement uncertainty of the whole process. Evaluation of measurement uncertainty of results is one of the requirements of the standard ISO/IEC 17025:2005 (European Standard EN IS/ISO/IEC 17025:2005, issue1:1-28, 2006). In the presented study the uncertainty estimation in mercury determination in suspended particulate matter (SPM) has been carried out using cold vapor Atomic Absorption Spectrometer-Hydride Generator (AAS-HG) technique followed by wet chemical digestion process. For the calculation of uncertainty, we have considered many general potential sources of uncertainty. After the analysis of data of seven diverse sites of Delhi, it has been concluded that the mercury concentration varies from 1.59 ± 0.37 to 14.5 ± 2.9 ng/m(3) with 95% confidence level (k = 2).

Improving the organic and biological fouling resistance and removal of pharmaceutical and personal care products through nanofiltration by using in situ radical graft polymerization.

PubMed

Lin, Yi-Li; Tsai, Chia-Cheng; Zheng, Nai-Yun

2018-09-01

In this study, an insitu radical graft polarization technique using monomers of 3-sulfopropyl methacrylate potassium salt (SPM) and 2-hydroxyethyl methacrylate (HEMA) was applied to a commercial nanofiltration membrane (NF90) to improve its removal of six commonly detected pharmaceutical and personal care products (PPCPs) and mitigate organic and biological fouling by humic acid (HA) and sodium alginate (SA). Compared with the virgin membrane, the modified NF90 membrane exhibited considerably improved fouling resistance and an increased reversible fouling percentage, especially for SA+HA composite fouling Moreover, the PPCP removal of the modified NF90 membrane was higher than that of the virgin membrane after SA and SA+HA fouling, respectively. Triclosan and carbamazepine, which are poorly rejected, could be effectively removed by modified membrane after SA or SA+HA fouling. Both monomers modified the membrane surface by increasing the hydrophilicity and decreasing the contact angle. The degree of grafting was quantified using attenuated total reflection Fourier-transform infrared spectroscopy. The mitigation in the fouling was evident from the low quantity of deposit formed on the modified membrane, as observed using scanning electron microscopy. A considerable amount of highly hydrophobic triclosan was adsorbed on the SA-fouled virgin membrane and penetrated through it. By contrast, the adsorption of triclosan was substantially lower in the SPM-modified membrane. After membrane modification, the fouling mechanism changed from solely intermediate blocking to both intermediate blocking and complete blocking after membrane modification. Thus, the in situ radical graft polymerization method effectively reduces organic and biological fouling and provides high PPCP removal, which is beneficial for fouling control and produces permeate of satisfactory quality for application in the field of membrane technology. Copyright © 2018 Elsevier B.V. All rights reserved.

Virtual Electrochemical Strain Microscopy of Polycrystalline LiCoO2 Films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chung, Ding-wen; Balke, Nina; Kalinin, Sergei V

2011-01-01

A recently developed technique, electrochemical strain microscopy (ESM), utilizes the strong coupling between ionic current and anisotropic volumetric chemical expansion of lithium-ion electrode materials to dynamically probe the sub-one-hundred? nm inter-facial kinetic intercalation properties. A numerical technique based on the finite element method was developed to analyze the underlying physics that govern the ESM signal generation and establish relations to battery performance. The performed analysis demonstrates that the diffusion path within a thin film is tortuous and the extent of lithium diffusion into the electrode is dependent on the SPM-tip-imposed overpotential frequency. The detected surface actuation gives rise to themore » development of an electromechanical hysteresis loop whose shape is dependent on grain size and overpotential frequency. Shape and tilting angle of the loop are classified into low and high frequency regimes, separated by a transition frequency which is also a function of lithium diffusivity and grain size, f{sub T} = D//{sup 2}. Research shows that the crystallographic orientation of the surface actuated grain has a significant impact on the shape of the loop. The polycrystalline crystallographic orientation of the grains induces a diffusion path network in the electrode which impacts on the mechanical reliability of the battery. Simulations demonstrate that continuous battery cycling results in a cumulative capacity loss as a result of the hysteric non-reversible lithium intercalation. Furthermore, results suggest that ESM has the capability to infer the local out-of-plane lithium diffusivity and the out-of-plane contribution to Vegard tensor.« less

Virtual Electrochemical Strain Microscopy of Polycrystalline LiCoO2 Films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chung, Ding-Wen; Balke, Nina; Kalinin, Sergei V.

2011-08-03

A recently developed technique, electrochemical strain microscopy (ESM), utilizes the strong coupling between ionic current and anisotropic volumetric chemical expansion of lithium-ion electrode materials to dynamically probe the sub-one-hundred? nm inter-facial kinetic intercalation properties. A numerical technique based on the finite element method was developed to analyze the underlying physics that govern the ESM signal generation and establish relations to battery performance. The performed analysis demonstrates that the diffusion path within a thin film is tortuous and the extent of lithium diffusion into the electrode is dependent on the SPM-tip-imposed overpotential frequency. The detected surface actuation gives rise to themore » development of an electromechanical hysteresis loop whose shape is dependent on grain size and overpotential frequency. Shape and tilting angle of the loop are classified into low and high frequency regimes, separated by a transition frequency which is also a function of lithium diffusivity and grain size, f T = D/l₂. Research shows that the crystallographic orientation of the surface actuated grain has a significant impact on the shape of the loop. The polycrystalline crystallographic orientation of the grains induces a diffusion path network in the electrode which impacts on the mechanical reliability of the battery. Simulations demonstrate that continuous battery cycling results in a cumulative capacity loss as a result of the hysteric non-reversible lithium intercalation. Furthermore, results suggest that ESM has the capability to infer the local out-of-plane lithium diffusivity and the out-of-plane contribution to Vegard tensor.« less

Solid-phase extraction and high-performance liquid chromatographic separation of pigments of red wines.

PubMed

Csiktusnádi Kiss, G A; Forgács, E; Cserháti, T; Candeias, M; Vilas-Boas, L; Bronze, R; Spranger, I

2000-08-11

The adsorption and desorption capacities of 11 different solid-phase extraction sorbents were tested for the preconcenration of pigments of various Hungarian red wines. The concentrates were evaluated by multiwavelengh spectrophotometry combined with a spectral mapping technique (SPM) and by reversed-phase high-performance liquid chromatography. The highest (10-fold) concentration of pigments was achieved on octadecylsilica sorbent. It can be used five times without losing adsorption and desorption characteristics. SPM indicated that multiwavelength spectrophotometry can be employed for the differentiation of red wines. Comparison of the chromatograms of pigments with and without preconcentration showed that preconcentration makes possible the separation and detection of pigments present in low concentration in red wines.

Probing and mapping electrode surfaces in solid oxide fuel cells.

PubMed

Blinn, Kevin S; Li, Xiaxi; Liu, Mingfei; Bottomley, Lawrence A; Liu, Meilin

2012-09-20

Solid oxide fuel cells (SOFCs) are potentially the most efficient and cost-effective solution to utilization of a wide variety of fuels beyond hydrogen (1-7). The performance of SOFCs and the rates of many chemical and energy transformation processes in energy storage and conversion devices in general are limited primarily by charge and mass transfer along electrode surfaces and across interfaces. Unfortunately, the mechanistic understanding of these processes is still lacking, due largely to the difficulty of characterizing these processes under in situ conditions. This knowledge gap is a chief obstacle to SOFC commercialization. The development of tools for probing and mapping surface chemistries relevant to electrode reactions is vital to unraveling the mechanisms of surface processes and to achieving rational design of new electrode materials for more efficient energy storage and conversion(2). Among the relatively few in situ surface analysis methods, Raman spectroscopy can be performed even with high temperatures and harsh atmospheres, making it ideal for characterizing chemical processes relevant to SOFC anode performance and degradation(8-12). It can also be used alongside electrochemical measurements, potentially allowing direct correlation of electrochemistry to surface chemistry in an operating cell. Proper in situ Raman mapping measurements would be useful for pin-pointing important anode reaction mechanisms because of its sensitivity to the relevant species, including anode performance degradation through carbon deposition(8, 10, 13, 14) ("coking") and sulfur poisoning(11, 15) and the manner in which surface modifications stave off this degradation(16). The current work demonstrates significant progress towards this capability. In addition, the family of scanning probe microscopy (SPM) techniques provides a special approach to interrogate the electrode surface with nanoscale resolution. Besides the surface topography that is routinely collected by AFM and STM, other properties such as local electronic states, ion diffusion coefficient and surface potential can also be investigated(17-22). In this work, electrochemical measurements, Raman spectroscopy, and SPM were used in conjunction with a novel test electrode platform that consists of a Ni mesh electrode embedded in an yttria-stabilized zirconia (YSZ) electrolyte. Cell performance testing and impedance spectroscopy under fuel containing H2S was characterized, and Raman mapping was used to further elucidate the nature of sulfur poisoning. In situ Raman monitoring was used to investigate coking behavior. Finally, atomic force microscopy (AFM) and electrostatic force microscopy (EFM) were used to further visualize carbon deposition on the nanoscale. From this research, we desire to produce a more complete picture of the SOFC anode.

Probing and Mapping Electrode Surfaces in Solid Oxide Fuel Cells

PubMed Central

Blinn, Kevin S.; Li, Xiaxi; Liu, Mingfei; Bottomley, Lawrence A.; Liu, Meilin

2012-01-01

Solid oxide fuel cells (SOFCs) are potentially the most efficient and cost-effective solution to utilization of a wide variety of fuels beyond hydrogen 1-7. The performance of SOFCs and the rates of many chemical and energy transformation processes in energy storage and conversion devices in general are limited primarily by charge and mass transfer along electrode surfaces and across interfaces. Unfortunately, the mechanistic understanding of these processes is still lacking, due largely to the difficulty of characterizing these processes under in situ conditions. This knowledge gap is a chief obstacle to SOFC commercialization. The development of tools for probing and mapping surface chemistries relevant to electrode reactions is vital to unraveling the mechanisms of surface processes and to achieving rational design of new electrode materials for more efficient energy storage and conversion2. Among the relatively few in situ surface analysis methods, Raman spectroscopy can be performed even with high temperatures and harsh atmospheres, making it ideal for characterizing chemical processes relevant to SOFC anode performance and degradation8-12. It can also be used alongside electrochemical measurements, potentially allowing direct correlation of electrochemistry to surface chemistry in an operating cell. Proper in situ Raman mapping measurements would be useful for pin-pointing important anode reaction mechanisms because of its sensitivity to the relevant species, including anode performance degradation through carbon deposition8, 10, 13, 14 ("coking") and sulfur poisoning11, 15 and the manner in which surface modifications stave off this degradation16. The current work demonstrates significant progress towards this capability. In addition, the family of scanning probe microscopy (SPM) techniques provides a special approach to interrogate the electrode surface with nanoscale resolution. Besides the surface topography that is routinely collected by AFM and STM, other properties such as local electronic states, ion diffusion coefficient and surface potential can also be investigated17-22. In this work, electrochemical measurements, Raman spectroscopy, and SPM were used in conjunction with a novel test electrode platform that consists of a Ni mesh electrode embedded in an yttria-stabilized zirconia (YSZ) electrolyte. Cell performance testing and impedance spectroscopy under fuel containing H2S was characterized, and Raman mapping was used to further elucidate the nature of sulfur poisoning. In situ Raman monitoring was used to investigate coking behavior. Finally, atomic force microscopy (AFM) and electrostatic force microscopy (EFM) were used to further visualize carbon deposition on the nanoscale. From this research, we desire to produce a more complete picture of the SOFC anode. PMID:23023264

On improvement to the Shock Propagation Model (SPM) applied to interplanetary shock transit time forecasting

NASA Astrophysics Data System (ADS)

Li, H. J.; Wei, F. S.; Feng, X. S.; Xie, Y. Q.

2008-09-01

This paper investigates methods to improve the predictions of Shock Arrival Time (SAT) of the original Shock Propagation Model (SPM). According to the classical blast wave theory adopted in the SPM, the shock propagating speed is determined by the total energy of the original explosion together with the background solar wind speed. Noting that there exists an intrinsic limit to the transit times computed by the SPM predictions for a specified ambient solar wind, we present a statistical analysis on the forecasting capability of the SPM using this intrinsic property. Two facts about SPM are found: (1) the error in shock energy estimation is not the only cause of the prediction errors and we should not expect that the accuracy of SPM to be improved drastically by an exact shock energy input; and (2) there are systematic differences in prediction results both for the strong shocks propagating into a slow ambient solar wind and for the weak shocks into a fast medium. Statistical analyses indicate the physical details of shock propagation and thus clearly point out directions of the future improvement of the SPM. A simple modification is presented here, which shows that there is room for improvement of SPM and thus that the original SPM is worthy of further development.

One-dimensional statistical parametric mapping in Python.

PubMed

Pataky, Todd C

2012-01-01

Statistical parametric mapping (SPM) is a topological methodology for detecting field changes in smooth n-dimensional continua. Many classes of biomechanical data are smooth and contained within discrete bounds and as such are well suited to SPM analyses. The current paper accompanies release of 'SPM1D', a free and open-source Python package for conducting SPM analyses on a set of registered 1D curves. Three example applications are presented: (i) kinematics, (ii) ground reaction forces and (iii) contact pressure distribution in probabilistic finite element modelling. In addition to offering a high-level interface to a variety of common statistical tests like t tests, regression and ANOVA, SPM1D also emphasises fundamental concepts of SPM theory through stand-alone example scripts. Source code and documentation are available at: www.tpataky.net/spm1d/.

An estimate of the suspended particulate matter (SPM) transport in the southern North Sea using SeaWiFS images, in situ measurements and numerical model results

NASA Astrophysics Data System (ADS)

Fettweis, Michael; Nechad, Bouchra; Van den Eynde, Dries

2007-06-01

A study is presented where satellite images (SeaWiFS), in situ measurements (tidal cycle and snapshot) and a 2D hydrodynamic numerical model have been combined to calculate the long term SPM (Suspended Particulate Matter) transport through the Dover Strait and in the southern North Sea. The total amount of SPM supplied to the North Sea through the Dover Strait is estimated to be 31.74×10 6 t. The satellite images provide synoptic views of SPM concentration distribution but do not take away the uncertainty of SPM transport calculation. This is due to the fact that SPM concentration varies as a function of tide, wind, spring-neap tidal cycles and seasons. The short term variations (tidal, spring-neap tidal cycle) have not been found in the satellite images, however seasonal variations are clearly visible. Furthermore the SPM concentration in the satellite images is generally lower than in the in situ measurements. The representativness of SPM concentration maps derived from satellites for calculating long term transports has therefore been investigated by comparing the SPM concentration variability from the in situ measurements with those of the remote sensing data. The most important constraints of satellite images are related to the fact that satellite data is evidence of clear sky conditions, whereas in situ measurements from a vessel can be carried out also during rougher meteorological conditions and that due to the too low time resolution of the satellite images the SPM concentration peaks are often missed. It is underlined that SPM concentration measurements should be carried out during at least one tidal cycle in high turbidity areas to obtain representative values of SPM concentration.

Preparation of RNA from bacteria infected with bacteriophages: a case study from the marine unicellular Synechococcus sp. WH7803 infected by phage S-PM2.

PubMed

Shan, Jinyu; Clokie, Martha

2009-01-01

Bacteriophages manipulate bacterial gene expression in order to express their own genes or influence bacterial metabolism. Gene expression can be studied using real-time PCR or microarrays. Either technique requires the prior isolation of high quality RNA uncontaminated by the presence of genomic DNA. We outline the considerations necessary when working with bacteriophage infected bacterial cells. We also give an example of a protocol for extraction and quantification of high quality RNA from infected bacterial cells, using the marine cyanobacterium WH7803 and the phage S-PM2 as a case study. This protocol can be modified to extract RNA from the host/bacteriophage of interest.

Chemically engineered graphene-based 2D organic molecular magnet.

PubMed

Hong, Jeongmin; Bekyarova, Elena; de Heer, Walt A; Haddon, Robert C; Khizroev, Sakhrat

2013-11-26

Carbon-based magnetic materials and structures of mesoscopic dimensions may offer unique opportunities for future nanomagnetoelectronic/spintronic devices. To achieve their potential, carbon nanosystems must have controllable magnetic properties. We demonstrate that nitrophenyl functionalized graphene can act as a room-temperature 2D magnet. We report a comprehensive study of low-temperature magnetotransport, vibrating sample magnetometry (VSM), and superconducting quantum interference (SQUID) measurements before and after radical functionalization. Following nitrophenyl (NP) functionalization, epitaxially grown graphene systems can become organic molecular magnets with ferromagnetic and antiferromagnetic ordering that persists at temperatures above 400 K. The field-dependent, surface magnetoelectric properties were studied using scanning probe microscopy (SPM) techniques. The results indicate that the NP-functionalization orientation and degree of coverage directly affect the magnetic properties of the graphene surface. In addition, graphene-based organic magnetic nanostructures were found to demonstrate a pronounced magneto-optical Kerr effect (MOKE). The results were consistent across different characterization techniques and indicate room-temperature magnetic ordering along preferred graphene orientations in the NP-functionalized samples. Chemically isolated graphene nanoribbons (CINs) were observed along the preferred functionality directions. These results pave the way for future magnetoelectronic/spintronic applications based on promising concepts such as current-induced magnetization switching, magnetoelectricity, half-metallicity, and quantum tunneling of magnetization.

Development of an osmotic pump system for controlled delivery of diclofenac sodium.

PubMed

Emara, L H; Taha, N F; Badr, R M; Mursi, N M

2012-10-01

Based on an elementary osmotic pump, controlled release systems of diclofenac sodium (DS) were designed to deliver the drug in a zero-order release pattern. Osmotic pump tablets containing 100 mg DS were prepared and coated with either semipermeable (SPM) or microporous (PM) membranes. The tablet coats were composed of hydrophobic triacetin (TA) or hydrophilic polyethylene glycol 400 (PEG 400) incorporated in cellulose acetate (CA) solution, for SPM and PM, respectively. Variable tablet core compositions such as swelling polymers (PEO and HPMC) and osmotic agents (lactose, NaCl, and KCl) were studied. An optimized, sensitive and well controlled in vitro release design, based on the flow-through cell (FTC), was utilized to discriminate between preparations. The results revealed that the presence of PEG 400 in the coating membrane accelerated the drug release rate, while TA suppressed the release rate of DS. In the case of SPM, the amount of DS released was inversely proportional to the membrane thickness, where 5% (w/w) weight gain gave a higher DS release rate than 10% (w/w). Results of different tablet core compositions revealed that the release rate of DS decreased as PEO molecular weight increased. HPMC K15M showed the lowest DS release rate. The presence of lactose, KCl, or NaCl pronouncedly affected DS release rate depending on polymer type in the core. Scanning electron microscopy (SEM) confirmed formation of pores in the membrane that accounts for faster DS release rate. These results revealed that DS could be formulated as an osmotic pump system with a prolonged, zero-order release pattern.

Carbon Nanotube Based Nano-Electro-Mechanical Systems (NEMS)

NASA Technical Reports Server (NTRS)

Han, Jie; Dai, Hongjie; Saini, Subhash

1998-01-01

Carbon nanotubes (CNT) enable nanoelectromechanical systems (NEMS) because of their inherent nanostructure, intrinsic electric conductivity and mechanical resilience. The collaborative work between Stanford (experiment) and NASA Ames (theory and simulation) has made progress in two types of CNT based NEMS for nanoelectronics and sensor applications. The CNT tipped scanning probe microscopy (SPM) is a NEMS in which CNT tips are used for nanoscale probing, imaging and manipulating. It showed great improvement in probing surfaces and biological systems over conventional tips. We have recently applied it to write (lithography) and read (image) uniform SiO2 lines on large Si surface area at speed up to 0.5 mm per s. Preliminary work using approximately 10 nm multiwall nanotube tips produced approximately 10 nm structures and showed that the CNT tips didn't wear down when crashed as conventional tips often do. This presents a solution to the long standing tip-wear problem in SPM nanolithography. We have also explored potential of CNT tips in imaging DNA in water. Preliminary experiment using 10 nm CNT tips reached 5 nm resolution. The 1 nm nanolithography and 1 nm DNA imaging can be expected by using approximately 1 nm CNT tips. In contrast to CNT tipped SPM, we also fabricated CNT devices on silicon wafer in which CNTs connect patterned metallic lines on SiO2/Si by a simple chemical vapor deposition process. Using conventional lithography for silicon wafer, we have been able to obtain CNT based transistors and sensors. Investigations of the CNT NEMS as physical, biological and chemical sensors are in progress and will be discussed.

The application of surgical procedure manager (SPM): first experience with FESS.

PubMed

Feige, Katharina; Gollnick, Iris; Schmitz, Pia; Strauss, Gero

2017-09-01

In our hypothesis, the newly developed program SPM (surgical procedure manager) will ensure successful standardization and efficiency of the FESS (functional endoscopic sinus surgery) and therefore make a decisive contribution in terms of economization and improvement of intraoperative quality. Between 27th March 2015 and 8th October 2015, data from 259 FESS procedures were collected using the SPM. The study took place at the surgical desk, an operating room in the ACQUA clinic in Leipzig, Germany. 233 FESS (90%) of the total FESS (n = 259, 100%) were conducted entirely with SPM. 26 SPM terminations (10%) of 259 FESS remain, which are classified as actual SPM terminations-when the surgeon intentionally stops the SPM. The maximum time slot decreased clearly from 1 h 39 min (period A) to 1 h 10 min (period B). A time reduction can also be seen with the minimum duration of 13.5 min compared to 11 min. The variability of the time slot also decreases since the standard deviation is reduced by 4.5 min. On the basis of available recordings it can be postulated that the application of SPM is suitable for standardization for FESS. Standardization by means of SPM and minimal development can be recognized over a period of time. The SPM makes it possible to transfer the general advantages of mechanization on a concrete FESS and do not influence the medical processes nor even restrict the medical freedom. The users are still entirely free in the implementation of the respective procedure.

Radioprotection of Human Cell Nuclear DNA by Polyamines: Radiosensitivity of Chromatin is Influenced by Tightly Bound Spermine

NASA Technical Reports Server (NTRS)

Warters, Raymond L.; Newton, Gerald L.; Olive, Peggy L.; Fahey, Robert C.

1999-01-01

The polyamines putrescine (PUT) and spermine (SPM) were examined for their ability to protect human cell Deoxyribonucleic Acid (DNA) against the formation of radiation-induced double-strand breaks (DSBs). As observed previously, under conditions where polyamines were shown to be almost completely absent, association with nuclear matrix protein into a nucleoid, and organization into chromatin structure, protected DNA from induction of DSBs by factors of 4.5 and 95, respectively. At concentrations below 1 mM, PUT or SPM provided equivalent levels of protection to deproteinized nuclear DNA, consistent with their capacity to scavenge radiation-induced radicals. At constant ionic strength, 5 mM SPM protected deproteinized DNA and nucleoid DNA and DNA in nuclear chromatin by factors of 100 and 26, respectively. At 5 mM, SPM provided 15 times greater protection of deproteinized DNA than did PUT. Under physiologically relevant conditions, 5 mM SPM protected DNA in the intact nucleus from the induction of DSBs by a factor of 2 relative to DNA in the absence of SPM. Studies of SPM binding during cellular fractionation revealed that a significant fraction of the cellular SPM is tightly bound in the nucleus but can be removed by extended washing. Thus the association of SPM with nuclear chromatin appears to be a significant contributor to the resistance of the cell's DNA to the induction of DSBs.

Solid Propellant Microthruster Design, Fabrication, and Testing for Nanosatellites

NASA Astrophysics Data System (ADS)

Sathiyanathan, Kartheephan

This thesis describes the design, fabrication, and testing of a solid propellant microthruster (SPM), which is a two-dimensional matrix of millimeter-sized rockets each capable of delivering millinewtons of thrust and millinewton-seconds of impulse to perform fine orbit and attitude corrections. The SPM is a potential payload for nanosatellites to increase spacecraft maneuverability and is constrained by strict mass, volume, and power requirements. The dimensions of the SPM in the millimeter-scale result in a number of scaling issues that need consideration such as a low Reynolds number, high heat loss, thermal and radical quenching, and incomplete combustion. The design of the SPM, engineered to address these issues, is outlined. The SPM fabrication using low-cost commercial off-the-shelf materials and standard micromachining is presented. The selection of a suitable propellant and its customization are described. Experimental results of SPM firing to demonstrate successful ignition and sustained combustion are presented for three configurations: nozzleless, sonic nozzle, and supersonic nozzle. The SPM is tested using a ballistic pendulum thrust stand. Impulse and thrust values are calculated and presented. The performance values of the SPM are found to be consistent with existing designs.

Large area high-speed metrology SPM system.

PubMed

Klapetek, P; Valtr, M; Picco, L; Payton, O D; Martinek, J; Yacoot, A; Miles, M

2015-02-13

We present a large area high-speed measuring system capable of rapidly generating nanometre resolution scanning probe microscopy data over mm(2) regions. The system combines a slow moving but accurate large area XYZ scanner with a very fast but less accurate small area XY scanner. This arrangement enables very large areas to be scanned by stitching together the small, rapidly acquired, images from the fast XY scanner while simultaneously moving the slow XYZ scanner across the region of interest. In order to successfully merge the image sequences together two software approaches for calibrating the data from the fast scanner are described. The first utilizes the low uncertainty interferometric sensors of the XYZ scanner while the second implements a genetic algorithm with multiple parameter fitting during the data merging step of the image stitching process. The basic uncertainty components related to these high-speed measurements are also discussed. Both techniques are shown to successfully enable high-resolution, large area images to be generated at least an order of magnitude faster than with a conventional atomic force microscope.

Large area high-speed metrology SPM system

NASA Astrophysics Data System (ADS)

Klapetek, P.; Valtr, M.; Picco, L.; Payton, O. D.; Martinek, J.; Yacoot, A.; Miles, M.

2015-02-01

We present a large area high-speed measuring system capable of rapidly generating nanometre resolution scanning probe microscopy data over mm2 regions. The system combines a slow moving but accurate large area XYZ scanner with a very fast but less accurate small area XY scanner. This arrangement enables very large areas to be scanned by stitching together the small, rapidly acquired, images from the fast XY scanner while simultaneously moving the slow XYZ scanner across the region of interest. In order to successfully merge the image sequences together two software approaches for calibrating the data from the fast scanner are described. The first utilizes the low uncertainty interferometric sensors of the XYZ scanner while the second implements a genetic algorithm with multiple parameter fitting during the data merging step of the image stitching process. The basic uncertainty components related to these high-speed measurements are also discussed. Both techniques are shown to successfully enable high-resolution, large area images to be generated at least an order of magnitude faster than with a conventional atomic force microscope.

Characteristic Evaluation of Synchronous Motors Using an Universal Drive System with a Real-Time Interface

NASA Astrophysics Data System (ADS)

Amano, Yoko; Ogasawara, Satoshi

In this paper, a new universal drive system of synchronous motors used Real-Time Interface (RTI) performs characteristic evaluation of Synchronous Reluctance (SynR) motors and Surface Permanent Magnet (SPM) synchronous motors. The RTI connects directly a simulation model with experimental equipment, and makes it possible to use the simulation model for an experiment. The RTI is very effective in the early detection of an actual problem and examination of solution technique. Moreover, it concentrates on examination of control algorithm, and efficient research and development are enabled. A measuring system of synchronous motors is built by the universal drive system. The examination of various synchronous motors is possible for the measurement system using the same control algorithm. Characteristic evaluation of a SynR motor and a SPM synchronous motor that are the same gap length and stator was performed using the measuring system. The measurement result shows experimentally that motor loss of the SynR motor is smaller rather than the SPM synchronous motor, at the time of high speed and low load operation. For example, the SynR motor is suitable to hybrid cars with the comparatively long time of low load and high-speed operation.

Impact of latency time on survival for adolescents and young adults with a second primary malignancy.

PubMed

Goldfarb, Melanie; Rosenberg, Aaron S; Li, Qian; Keegan, Theresa H M

2018-03-15

The adverse impact of second primary malignancies (SPMs) on survival is substantial for adolescents and young adults (AYAs; ie, those 15-39 years old). No studies have evaluated whether the latency time between the first malignancy (the primary malignancy [PM]) and the SPM affects cancer-specific survival (CSS). A multivariate Cox proportional hazards regression with Surveillance, Epidemiology, and End Results data for 13 regions from 1992 to 2008 was used to ascertain whether the latency time (1-5 vs ≥ 6 years) to the development of an SPM affected the CSS and overall survival with respect to either the PM or SPM for AYAs with common SPMs. The majority of 1515 AYAs with an SPM had their PM diagnosed between the ages of 26 and 39 years (74.2%) and an SPM diagnosed within 1 to 5 years (72.9%) of the PM's diagnosis. Overall, AYAs that developed an SPM 1 to 5 years after the diagnosis (vs ≥ 6 years) had an increased risk of death from cancer (hazard ratio [HR], 2.52; 95% confidence interval [CI], 1.92-3.29) as well as any cause (HR, 2.60; 95% CI, 2.04-3.32). Specifically, for AYAs with an SPM that was leukemia or a colorectal, breast, or central nervous system malignancy, a shorter latency time (1-5 years) from their PM diagnosis was associated with an overall significantly increased risk of death (2.6-fold) from either their PM or that particular SPM. However, latency did not appear to affect the CSS with respect to either the PM or SPM for AYA patients with a lymphoma or sarcoma SPM. Most AYAs who develop an SPM do so within 1 to 5 years of their primary cancer diagnosis, and they have an increased risk of death from cancer in comparison with AYAs with an SPM developing after longer survivorship intervals. Cancer 2018;124:1260-8. © 2017 American Cancer Society. © 2017 American Cancer Society.

Evaluating Several Hundred Predictors for Suspended Particulate Matter in the Northern Gulf of Mexico Using Inherent and Apparent Optical Properties & Considering Their Applicability for Use With Bathymetric Lidar Surveys

NASA Astrophysics Data System (ADS)

Epps, S. A.

2017-12-01

Suspended particulate matter (SPM) is an important agent in generating marine light conditions which in turn have strong influences on biogeochemical systems. SPM also behaves as a vehicle for contaminant migration and is of interest to the estimation of bulk material transport in the marine environment. The measurement of inherent optical properties (IOPs) and apparent optical properties (AOPs) is becoming increasingly important in the prediction of SPM concentration. To more fully utilize data generated in bathymetric lidar surveys, modern systems such as CZMIL (the Coastal Zone Mapping Imaging LIDAR) include a hyperspectral sensor to collect data necessary for remote sensing reflectance (Rrs), an AOP. Some IOPs can be estimated can be estimated from Rrs. Additionally, a bathymetric lidar return signal contains both absorption and backscattering components (IOPs) at 532 nm which may be utilized for SPM prediction. This research utilizes IOP measurements using AC-9, AC-S, BB-9, and LISST-100X-B sensors deployed in the Northern Gulf of Mexico concurrent with SPM collection via filtration. Concomitant Rrs values were collected using a hand held hyperspectral sensor. Several hundred linearly regressed single-parameter estimates are created to predict SPM concentration using the IOPs attenuation, total scatter, backscatter, absorption and significant amalgamations thereof. Multiple wavelengths of light are analyzed for each IOP or IOP combination. Consideration is given to the suitability of each IOP type to SPM concentration prediction. Several criteria are assessed to winnow out the best predictors. These include sensor, data, and environmental limitations. The quantitative analyses of this research assist to identify the best types of IOPs (and wavelengths) for SPM prediction. Rrs at multiple wavelengths is also considered for SPM prediction. This research is focused on the functionality of IOP and AOP based SPM concentration predictions made available from the data products of bathymetric lidar surveys. It has applications for researchers with interest in IOPs, AOPs and SPM. There are also implications for monitoring estuarine, coastal, and offshore environments using bathymetric lidar and in-situ optical sensor suites to estimate SPM.

Open-loop measurement of data sampling point for SPM

NASA Astrophysics Data System (ADS)

Wang, Yueyu; Zhao, Xuezeng

2006-03-01

SPM (Scanning Probe Microscope) provides "three-dimensional images" with nanometer level resolution, and some of them can be used as metrology tools. However, SPM's images are commonly distorted by non-ideal properties of SPM's piezoelectric scanner, which reduces metrological accuracy and data repeatability. In order to eliminate this limit, an "open-loop sampling" method is presented. In this method, the positional values of sampling points in all three directions on the surface of the sample are measured by the position sensor and recorded in SPM's image file, which is used to replace the image file from a conventional SPM. Because the positions in X and Y directions are measured at the same time of sampling height information in Z direction, the image distortion caused by scanner locating error can be reduced by proper image processing algorithm.

Some effects on SPM based surface measurement

NASA Astrophysics Data System (ADS)

Wenhao, Huang; Yuhang, Chen

2005-01-01

The scanning probe microscope (SPM) has been used as a powerful tool for nanotechnology, especially in surface nanometrology. However, there are a lot of false images and modifications during the SPM measurement on the surfaces. This is because of the complex interaction between the SPM tip and the surface. The origin is not only due to the tip material or shape, but also to the structure of the sample. So people are paying much attention to draw true information from the SPM images. In this paper, we present some simulation methods and reconstruction examples for the microstructures and surface roughness based on SPM measurement. For example, in AFM measurement, we consider the effects of tip shape and dimension, also the surface topography distribution in both height and space. Some simulation results are compared with other measurement methods to verify the reliability.

Spermine alleviates drought stress in white clover with different resistance by influencing carbohydrate metabolism and dehydrins synthesis.

PubMed

Li, Zhou; Jing, Wen; Peng, Yan; Zhang, Xin Quan; Ma, Xiao; Huang, Lin Kai; Yan, Yan-Hong

2015-01-01

The objective of this research was to analyse whether ameliorating drought stress through exogenously applied spermine (Spm) was related to carbohydrate metabolism, dehydrins accumulation and the transcription of genes encoding dehydrins in two white clovers (drought-susceptible cv. 'Ladino' and drought-resistant cv. 'Haifa') under controlled drying conditions for 10 days. The results show that the application of Spm effectively alleviates negative effects caused by drought stress in both cultivars. Exogenous Spm led to accumulation of more water-soluble carbohydrates (WSC), sucrose, fructose and sorbitol in both cultivars under drought stress, and also significantly elevated glucose content in leaves of drought-resistant cv. 'Haifa', but had no effect on drought-susceptible cv. 'Ladino'. Accordingly, the key enzyme activities of sucrose and sorbitol metabolism changed along with the application of Spm under drought stress. Spm induced a significant increase in sucrose phosphate synthase (SPS) or sorbitol dehydrogenase (SDH) activity, but decrease in sucrose synthetase (SS) activity when two cultivars were subjected to drought. In addition, the improved accumulation of dehydrins induced by exogenous Spm coincided with three genes expression which was responsible for dehydrins synthesis. But Spm-induced transcript level of dehydrin genes increased earlier in cv. 'Ladino' than that in cv. 'Haifa'. Thus, these results suggest that ameliorating drought stress through exogenously applied Spm may be associated with increased carbohydrate accumulation and dehydrins synthesis. There are differences between drought-susceptible and -resistant white clover cultivars related to Spm regulation of WSC metabolism and dehydrins expression.

Effectiveness of mathematics education in secondary schools to meet the local universities missions in producing quality engineering and science undergraduates

NASA Astrophysics Data System (ADS)

Bakar Hasan, Abu; Fatah Abdul, Abdul; Selamat, Zalilah

2018-01-01

Critical claims by certain quarters that our local undergraduates are not performing well in Mathematics, Statistics and Numerical Methods needs a serious thinking and actions. Yearly examinations results from the Sijil Pelajaran Malaysia (SPM equivalent to A-Level) and Sijil Tinggi Pelajaran Malaysia (STPM equivalent to O-Level) levels have been splendid whereby it is either increasing or decreasing in a very tight range. A good foundation in mathematics and additional mathematics will tremendously benefit these students when they enter their university education especially in engineering and science courses. This paper uses SPM results as the primary data, questionnaires as secondary, and apply the Fish Bones technique for analysis. The outcome shows that there is a clear correlation between the causes and effect.

Smoothed spectra for enhanced dispersion-free pulse duration reduction of passively Q-switched microchip lasers.

PubMed

Lehneis, R; Jauregui, C; Steinmetz, A; Limpert, J; Tünnermann, A

2014-02-01

We present an enhanced technique for dispersion-free pulse shortening, which exploits the interplay of different third-order nonlinear effects in a waveguide structure. When exceeding a certain value of the pulse energy coupled into the waveguide, the typical oscillations of self-phase modulation (SPM)-broadened spectra vanish during pulse propagation. Such smoothed spectra ensure a high pulse quality of the spectrally filtered and, therefore, temporally shortened pulses independently of the filtering position. A reduction of the pulse duration from 138 to 24 ps has been achieved while preserving a high temporal quality. To the best of our knowledge, the nonlinear smoothing of SPM-broadened spectra is used in the context of dispersion-free pulse duration reduction for the first time.

Study on the occurrence of platinum in Xinjie CuNi sulfide deposits by a combination of SPM and NAA

NASA Astrophysics Data System (ADS)

Li, Xiaolin; Zhu, Jieqing; Lu, Rongrong; Gu, Yingmei; Wu, Xiankang; Chen, Youhong

1997-07-01

A combination of neutron-activation analysis (NAA) and scanning proton microprobe (SPM) was used to study the distribution of platinum-group elements (PGEs) in rocks and ores from Xinjie CuNi deposit. The minimum detection limits of PGEs by NAA had been much improved by means of a nickel-sulfide fire-assay technique for pre-concentration of PGEs in the ore samples. A simple and effective method was developed for true element mapping in SPM experiments. A pair of moveable absorption filters was set up in the target chamber for high sensitivities of both major and trace elements. The bulk analysis results by NNA indicated that the PGE mineralization occurred at the base of Xinjie layered intrusion in clinopyroxenite rocks and the CuNi sulfide minerals disseminated within the rocks had high abundance level of PGEs. However, the micro-PIXE analysis of the CuNi sulfide mineral grains did not find PGEs above the MDL of 6-9 ppm for Rh, Ru and Pd, and 60 ppm for Pt. The search for platinum occurrence in sulfide minerals was followed by scanning analysis of SPM when some smaller platinum enriched grains were found in the sulfide minerals. The microscopic analysis results suggested that platinum occurred in the CuNi sulfide matrix as independent arsenide mineral grains. The chemical formula of the arsenide sperrylite was PtAs 2. The information of the platinum occurrence was helpful to future mineralogical research and mineral processing and beneficiation of the CuNi deposit.

In-phase oscillation of global regulons is orchestrated by a pole-specific organizer

PubMed Central

Janakiraman, Balaganesh; Mignolet, Johann; Narayanan, Sharath; Viollier, Patrick H.

2016-01-01

Cell fate determination in the asymmetric bacterium Caulobacter crescentus (Caulobacter) is triggered by the localization of the developmental regulator SpmX to the old (stalked) cell pole during the G1→S transition. Although SpmX is required to localize and activate the cell fate-determining kinase DivJ at the stalked pole in Caulobacter, in cousins such as Asticcacaulis, SpmX directs organelle (stalk) positioning and possibly other functions. We define the conserved σ54-dependent transcriptional activator TacA as a global regulator in Caulobacter whose activation by phosphorylation is indirectly down-regulated by SpmX. Using a combination of forward genetics and cytological screening, we uncover a previously uncharacterized and polarized component (SpmY) of the TacA phosphorylation control system, and we show that SpmY function and localization are conserved. Thus, SpmX organizes a site-specific, ancestral, and multifunctional regulatory hub integrating the in-phase oscillation of two global transcriptional regulators, CtrA (the master cell cycle transcriptional regulator A) and TacA, that perform important cell cycle functions. PMID:27791133

Joint sparse coding based spatial pyramid matching for classification of color medical image.

PubMed

Shi, Jun; Li, Yi; Zhu, Jie; Sun, Haojie; Cai, Yin

2015-04-01

Although color medical images are important in clinical practice, they are usually converted to grayscale for further processing in pattern recognition, resulting in loss of rich color information. The sparse coding based linear spatial pyramid matching (ScSPM) and its variants are popular for grayscale image classification, but cannot extract color information. In this paper, we propose a joint sparse coding based SPM (JScSPM) method for the classification of color medical images. A joint dictionary can represent both the color information in each color channel and the correlation between channels. Consequently, the joint sparse codes calculated from a joint dictionary can carry color information, and therefore this method can easily transform a feature descriptor originally designed for grayscale images to a color descriptor. A color hepatocellular carcinoma histological image dataset was used to evaluate the performance of the proposed JScSPM algorithm. Experimental results show that JScSPM provides significant improvements as compared with the majority voting based ScSPM and the original ScSPM for color medical image classification. Copyright © 2014 Elsevier Ltd. All rights reserved.

Exogenous polyamines elicit herbivore-induced volatiles in lima bean leaves: involvement of calcium, H2O2 and Jasmonic acid.

PubMed

Ozawa, Rika; Bertea, Cinzia M; Foti, Maria; Narayana, Ravishankar; Arimura, Gen-Ichiro; Muroi, Atsushi; Horiuchi, Jun-Ichiro; Nishioka, Takaaki; Maffei, Massimo E; Takabayashi, Junji

2009-12-01

We investigated the role of polyamines (PAs) in lima bean (Phaseolus lunatus) leaves on the production of herbivorous mite (Tetranychus urticae)-induced plant volatiles that attract carnivorous natural enemies of the herbivores. To do this, we focused on the effects of the exogenous PAs [cadaverine, putrescine, spermidine and spermine (Spm)] on the production of volatiles, H(2)O(2) and jasmonic acid (JA) and the levels of defensive genes, cytosolic calcium and reactive oxygen species (ROS). Among the tested PAs, Spm was the most active in inducing the production of volatile terpenoids known to be induced by T. urticae. An increase in JA levels was also found after Spm treatment, indicating that Spm induces the biosynthesis of JA, which has been shown elsewhere to regulate the production of some volatile terpenoids. Further, treatment with JA and Spm together resulted in greater volatile emission than that with JA alone. In a Y-tube olfactometer, leaves treated with Spm + JA attracted more predatory mites (Phytoseiulus persimilis) than those treated with JA alone. After treatment with Spm + JA, no effects were found on the enzyme activity of polyamine oxidase and copper amine oxidase. However, induction of calcium influx and ROS production, and increased enzyme activities and gene expression for NADPH oxidase complex, superoxide dismutase, catalase, ascorbate peroxidase, glutathione reductase and glutathione peroxidase were found after treatment with Spm + JA. These results indicate that Spm plays an important role in the production of T. urticae-induced lima bean leaf volatiles.

Spermine Alleviates Drought Stress in White Clover with Different Resistance by Influencing Carbohydrate Metabolism and Dehydrins Synthesis

PubMed Central

Li, Zhou; Jing, Wen; Peng, Yan; Zhang, Xin Quan; Ma, Xiao; Huang, Lin Kai; Yan, Yan-hong

2015-01-01

The objective of this research was to analyse whether ameliorating drought stress through exogenously applied spermine (Spm) was related to carbohydrate metabolism, dehydrins accumulation and the transcription of genes encoding dehydrins in two white clovers (drought-susceptible cv. ‘Ladino’ and drought-resistant cv. ‘Haifa’) under controlled drying conditions for 10 days. The results show that the application of Spm effectively alleviates negative effects caused by drought stress in both cultivars. Exogenous Spm led to accumulation of more water-soluble carbohydrates (WSC), sucrose, fructose and sorbitol in both cultivars under drought stress, and also significantly elevated glucose content in leaves of drought-resistant cv. ‘Haifa’, but had no effect on drought-susceptible cv. ‘Ladino’. Accordingly, the key enzyme activities of sucrose and sorbitol metabolism changed along with the application of Spm under drought stress. Spm induced a significant increase in sucrose phosphate synthase (SPS) or sorbitol dehydrogenase (SDH) activity, but decrease in sucrose synthetase (SS) activity when two cultivars were subjected to drought. In addition, the improved accumulation of dehydrins induced by exogenous Spm coincided with three genes expression which was responsible for dehydrins synthesis. But Spm-induced transcript level of dehydrin genes increased earlier in cv. ‘Ladino’ than that in cv. ‘Haifa’. Thus, these results suggest that ameliorating drought stress through exogenously applied Spm may be associated with increased carbohydrate accumulation and dehydrins synthesis. There are differences between drought-susceptible and -resistant white clover cultivars related to Spm regulation of WSC metabolism and dehydrins expression. PMID:25835290

A quantitative comparison of resolution, scanning speed and lifetime behavior of CVD grown Single Wall Carbon Nanotubes and silicon SPM probes using spectral methods

NASA Astrophysics Data System (ADS)

Krause, O.; Bouchiat, V.; Bonnot, A. M.

2007-03-01

Due to their extreme aspect ratios and exceptional mechanical properties Carbon Nanotubes terminated silicon probes have proven to be the ''ideal'' probe for Atomic Force Microscopy. But especially for the manufacturing and use of Single Walled Carbon Nanotubes there are serious problems, which have not been solved until today. Here, Single and Double Wall Carbon Nanotubes, batch processed and used as deposited by Chemical Vapor Deposition without any postprocessing, are compared to standard and high resolution silicon probes concerning resolution, scanning speed and lifetime behavior.

Multi-Wall Carbon Nanotubes as Lithium Nanopipettes and SPM Probes

NASA Astrophysics Data System (ADS)

Larson, Jonathan; Bharath, Satyaveda; Cullen, William; Reutt-Robey, Janice

2014-03-01

A multi-walled carbon nanotube (MWCNT) - terminated SPM cantilever, was utilized to perform nanolithography and surface diffusion measurements on a thin film of vapor-deposited lithium atop a silicon (111) substrate under ultra-high vacuum conditions. In these investigations the MWCNT tip was shown to act as both a lithium nanopipette and a probe for non-contact atomic force microscopy (NC-AFM) measurements. With the application of appropriate bias conditions, the MWCNT could site-selectively extract (expel) nano-scale amounts of lithium from (to) the sample surface. Depressions, mounds, and spikes were generated on the surface in this way and were azimuthally symmetric about the selected point of pipetting. Following lithium transfer to/from the substrate, the MWCNT pipette-induced features were sequentially imaged with NC-AFM using the MWCNT as the probe. Vacancy pits of ca. 300 nm diameter and 1.5 nm depth were observed to decay on a timescale of hours at room temperature, through diffusion-limited decay processes. A continuum model was utilized to simulate the island decay rates, and the lithium surface diffusion coefficient of D =7.5 (+/-1.3)*10-15 cm2/s was extracted. U.S. Department of Energy Award Number DESC0001160.

Biochemical effects and growth inhibition in MCF-7 cells caused by novel sulphonamido oxa-polyamine derivatives.

PubMed

Pavlov, V; Lin, P Kong Thoo; Rodilla, V

2002-04-01

The novel polyamine derivatives sulphonamido oxa-spermine (oxa-Spm) and sulphonamido oxa-spermidine (oxa-Spd) exhibited rapid cytotoxic action towards MCF-7 human breast cancer cells with IC50 values of 4.35 and 6.47 pM, respectively, after 24-h drug exposure. Neither compound is a substrate of serum amine oxidase. Both oxa-Spm and oxa-Spd caused cell shrinkage, as determined by phase-contrast microscopy. After incubation with 10 microM of either compound for 8 h, the cells underwent chromatin condensation and nuclear fragmentation. However, no clear DNA ladder was obtained by electrophoresis. The sulphonamido oxa-polyamine derivatives and especially oxa-Spd enhanced the activity of polyamine oxidase (PAO), an enzyme capable of oxidising N1-acetylated spermine and spermidine to spermidine and putrescine, respectively, generating cytotoxic H2O2 and 3-acetamidopropanal as by-products. The intracellular polyamine content was only marginally reduced in response to drug treatment. In conclusion, our data show that these novel sulphonamido oxa-polyamine derivatives possess high cytotoxic activity against MCF-7 cells and indicate that induction of PAO may mediate their cytotoxicity via apoptosis.

Decreasing trends of suspended particulate matter and PM2.5 concentrations in Tokyo, 1990-2010.

PubMed

Hara, Kunio; Homma, Junichi; Tamura, Kenji; Inoue, Mariko; Karita, Kanae; Yano, Eiji

2013-06-01

In Tokyo, the annual average suspended particulate matter (SPM) and PM2.5 concentrations have decreased in the past two decades. The present study quantitatively evaluated these decreasing trends using data from air-pollution monitoring stations. Annual SPM and PM2.5 levels at 83 monitoring stations and hourly SPM and PM2.5 levels at four monitoring stations in Tokyo, operated by the Tokyo Metropolitan Government, were used for analysis, together with levels of co-pollutants and meteorological conditions. Traffic volume in Tokyo was calculated from the total traveling distance of vehicles as reported by the Ministry of Land, Infrastructure, Transport, and Tourism. High positive correlations between SPM levels and nitrogen oxide levels, sulfur dioxide levels, and traffic volume were determined. The annual average SPM concentration declined by 62.6%from 59.4 microg/m3 in 1994 to 22.2 microg/m3 in 2010, and PM2.5 concentration also declined by 49.8% from 29.3 microg/m3 in 2001 to 14.7 microg/m3 in 2010. Likewise, the frequencies of hourly average SPM and PM2.5 concentrations exceeding the daily guideline values have significantly decreased since 2001 and the hourly average SPM or PM2.5 concentrations per traffic volume for each time period have also significantly decreased since 2001. However SPM and PM2.5 concentrations increased at some monitoring stations between 2004 and 2006 and from 2009 despite strengthened environmental regulations and improvements in vehicle engine performance. The annual average SPM and PM2.5 concentrations were positively correlated with traffic volumes and in particular with the volume of diesel trucks. These results suggest that the decreasing levels of SPM and PM2.5 in Tokyo may be attributable to decreased traffic volumes, along with the effects of stricter governmental regulation and improvements to vehicle engine performance, including the fitting of devices for exhaust emission reduction.

Mechanisms controlling the intra-annual mesoscale variability of SST and SPM in the southern North Sea

NASA Astrophysics Data System (ADS)

Pietrzak, Julie D.; de Boer, Gerben J.; Eleveld, Marieke A.

2011-04-01

Thermal and optical remote sensing data were used to investigate the spatial and temporal distribution of sea surface temperature (SST) and of suspended particulate matter (SPM) in the southern North Sea. Monthly SST composites showed pronounced seasonal warming of the southern North Sea and delineated the English coastal and continental coastal waters. The East-Anglia Plume is the dominant feature of the English coastal waters in the winter and autumn SPM composites, and the Rhine region of freshwater influence (ROFI), including the Flemish Banks, is the dominant feature of the continental waters. These mesoscale spatial structures are also influenced by the evolution of fronts, such as the seasonal front separating well-mixed water in the southern Bight, from the seasonally stratified central North Sea waters. A harmonic analysis of the SST and SPM images showed pronounced seasonal variability, as well as spring-neap variations in the level of tidal mixing in the East Anglia Plume, the Rhine ROFI and central North Sea. The harmonic analysis indicates the important role played by the local meteorology and tides in governing the SST and near-surface SPM concentrations in the southern North Sea. In the summer, thermal stratification affects the visibility of SPM to satellite sensors in the waters to the north of the Flamborough and Frisian Fronts. Haline stratification plays an important role in the visibility of SPM in the Rhine ROFI throughout the year. When stratified, both regions typically exhibit low surface SPM values. A numerical model study, together with the harmonic analysis, highlights the importance of tides and waves in controlling the stratification in the southern North Sea and hence the visibility of SPM.

Experimental vitrification of human compacted morulae and early blastocysts using fine diameter plastic micropipettes.

PubMed

Cremades, N; Sousa, M; Silva, J; Viana, P; Sousa, S; Oliveira, C; Teixeira da Silva, J; Barros, A

2004-02-01

Vitrification of human blastocysts has been successfully applied using grids, straws and cryoloops. We assessed the survival rate of human compacted morulae and early blastocysts vitrified in pipette tips with a smaller inner diameter and solution volume than the previously described open pulled straw (OPS) method. Excess day 5 human embryos (n = 63) were experimentally vitrified in vessels. Embryos were incubated at 37 degrees C with sperm preparation medium (SPM) for 1 min, SPM + 7.5% ethylene glycol (EG)/dimethylsulphoxide (DMSO) for 3 min, and SPM + 16.5% EG + 16.5% DMSO + 0.67 mol/l sucrose for 25 s. They were then aspirated (0.5 microl) into a plastic micropipette tip (0.36 mm inner diameter), exposed to liquid nitrogen (LN(2)) vapour for 2 min before being placed into a pre-cooled cryotube, which was then closed and plunged into LN(2). Embryos were warmed and diluted using 0.33 mol/l and 0.2 mol/l sucrose. The survival rate for compacted morulae was 73% (22/30) and 82% (27/33) for early blastocysts. The survival rates of human compacted morulae and early blastocysts after vitrification with this simple technique are similar to those reported in the literature achieved by slow cooling and other vitrification protocols.

The Genome of S-PM2, a “Photosynthetic” T4-Type Bacteriophage That Infects Marine Synechococcus Strains

PubMed Central

Mann, Nicholas H.; Clokie, Martha R. J.; Millard, Andrew; Cook, Annabel; Wilson, William H.; Wheatley, Peter J.; Letarov, Andrey; Krisch, H. M.

2005-01-01

Bacteriophage S-PM2 infects several strains of the abundant and ecologically important marine cyanobacterium Synechococcus. A large lytic phage with an isometric icosahedral head, S-PM2 has a contractile tail and by this criterion is classified as a myovirus (1). The linear, circularly permuted, 196,280-bp double-stranded DNA genome of S-PM2 contains 37.8% G+C residues. It encodes 239 open reading frames (ORFs) and 25 tRNAs. Of these ORFs, 19 appear to encode proteins associated with the cell envelope, including a putative S-layer-associated protein. Twenty additional S-PM2 ORFs have homologues in the genomes of their cyanobacterial hosts. There is a group I self-splicing intron within the gene encoding the D1 protein. A total of 40 ORFs, organized into discrete clusters, encode homologues of T4 proteins involved in virion morphogenesis, nucleotide metabolism, gene regulation, and DNA replication and repair. The S-PM2 genome encodes a few surprisingly large (e.g., 3,779 amino acids) ORFs of unknown function. Our analysis of the S-PM2 genome suggests that many of the unknown S-PM2 functions may be involved in the adaptation of the metabolism of the host cell to the requirements of phage infection. This hypothesis originates from the identification of multiple phage-mediated modifications of the host's photosynthetic apparatus that appear to be essential for maintaining energy production during the lytic cycle. PMID:15838046

Two-probe STM experiments at the atomic level.

PubMed

Kolmer, Marek; Olszowski, Piotr; Zuzak, Rafal; Godlewski, Szymon; Joachim, Christian; Szymonski, Marek

2017-11-08

Direct characterization of planar atomic or molecular scale devices and circuits on a supporting surface by multi-probe measurements requires unprecedented stability of single atom contacts and manipulation of scanning probes over large, nanometer scale area with atomic precision. In this work, we describe the full methodology behind atomically defined two-probe scanning tunneling microscopy (STM) experiments performed on a model system: dangling bond dimer wire supported on a hydrogenated germanium (0 0 1) surface. We show that 70 nm long atomic wire can be simultaneously approached by two independent STM scanners with exact probe to probe distance reaching down to 30 nm. This allows direct wire characterization by two-probe I-V characteristics at distances below 50 nm. Our technical results presented in this work open a new area for multi-probe research, which can be now performed with precision so far accessible only by single-probe scanning probe microscopy (SPM) experiments.

Design of a single projector multiview 3D display system

NASA Astrophysics Data System (ADS)

Geng, Jason

2014-03-01

Multiview three-dimensional (3D) display is able to provide horizontal parallax to viewers with high-resolution and fullcolor images being presented to each view. Most multiview 3D display systems are designed and implemented using multiple projectors, each generating images for one view. Although this multi-projector design strategy is conceptually straightforward, implementation of such multi-projector design often leads to a very expensive system and complicated calibration procedures. Even for a multiview system with a moderate number of projectors (e.g., 32 or 64 projectors), the cost of a multi-projector 3D display system may become prohibitive due to the cost and complexity of integrating multiple projectors. In this article, we describe an optical design technique for a class of multiview 3D display systems that use only a single projector. In this single projector multiview (SPM) system design, multiple views for the 3D display are generated in a time-multiplex fashion by the single high speed projector with specially designed optical components, a scanning mirror, and a reflective mirror array. Images of all views are generated sequentially and projected via the specially design optical system from different viewing directions towards a 3D display screen. Therefore, the single projector is able to generate equivalent number of multiview images from multiple viewing directions, thus fulfilling the tasks of multiple projectors. An obvious advantage of the proposed SPM technique is the significant reduction of cost, size, and complexity, especially when the number of views is high. The SPM strategy also alleviates the time-consuming procedures for multi-projector calibration. The design method is flexible and scalable and can accommodate systems with different number of views.

33 CFR 150.445 - When is oil in a single point mooring-oil transfer system (SPM-OTS) displaced with water?

Code of Federal Regulations, 2010 CFR

2010-07-01

... the pipeline end manifold must be closed whenever: (1) A storm warning forecasts weather conditions... vessel is about to depart the SPM because of storm conditions; or (3) The SPM is not scheduled for use in...

33 CFR 150.445 - When is oil in a single point mooring-oil transfer system (SPM-OTS) displaced with water?

Code of Federal Regulations, 2011 CFR

2011-07-01

... the pipeline end manifold must be closed whenever: (1) A storm warning forecasts weather conditions... vessel is about to depart the SPM because of storm conditions; or (3) The SPM is not scheduled for use in...

33 CFR 150.445 - When is oil in a single point mooring-oil transfer system (SPM-OTS) displaced with water?

Code of Federal Regulations, 2014 CFR

2014-07-01

... the pipeline end manifold must be closed whenever: (1) A storm warning forecasts weather conditions... vessel is about to depart the SPM because of storm conditions; or (3) The SPM is not scheduled for use in...

33 CFR 150.445 - When is oil in a single point mooring-oil transfer system (SPM-OTS) displaced with water?

Code of Federal Regulations, 2013 CFR

2013-07-01

... the pipeline end manifold must be closed whenever: (1) A storm warning forecasts weather conditions... vessel is about to depart the SPM because of storm conditions; or (3) The SPM is not scheduled for use in...

33 CFR 150.445 - When is oil in a single point mooring-oil transfer system (SPM-OTS) displaced with water?

Code of Federal Regulations, 2012 CFR

2012-07-01

... the pipeline end manifold must be closed whenever: (1) A storm warning forecasts weather conditions... vessel is about to depart the SPM because of storm conditions; or (3) The SPM is not scheduled for use in...

Comparison of remote sensing algorithms for retrieval of suspended particulate matter concentration from reflectance in coastal waters

NASA Astrophysics Data System (ADS)

Freeman, Lauren A.; Ackleson, Steven G.; Rhea, William Joseph

2017-10-01

Suspended particulate matter (SPM) is a key environmental indicator for rivers, estuaries, and coastal waters, which can be calculated from remote sensing reflectance obtained by an airborne or satellite imager. Here, algorithms from prior studies are applied to a dataset of in-situ at surface hyperspectral remote sensing reflectance, collected in three geographic regions representing different water types. These data show the optically inherent exponential nature of the relationship between reflectance and sediment concentration. However, linear models are also shown to provide a reasonable estimate of sediment concentration when utilized with care in similar conditions to those under which the algorithms were developed, particularly at lower SPM values (0 to 20 mg/L). Fifteen published SPM algorithms are tested, returning strong correlations of R2>0.7, and in most cases, R2>0.8. Very low SPM values show weaker correlation with algorithm calculated SPM that is not wavelength dependent. None of the tested algorithms performs well for high SPM values (>30 mg/L), with most algorithms underestimating SPM. A shift toward a smaller number of simple exponential or linear models relating satellite remote sensing reflectance to suspended sediment concentration with regional consideration will greatly aid larger spatiotemporal studies of suspended sediment trends.

Anti-Invasive and Anti-Proliferative Synergism between Docetaxel and a Polynuclear Pd-Spermine Agent

PubMed Central

Batista de Carvalho, Ana L. M.; Medeiros, Paula S. C.; Costa, Francisco M.; Ribeiro, Vanessa P.; Sousa, Joana B.; Marques, Maria P. M.

2016-01-01

The present work is aimed at evaluating the antitumour properties of a Pd(II) dinuclear complex with the biogenic polyamine spermine, by investigating: i) the anti-angiogenic and anti-migration properties of a Pd(II) dinuclear complex with spermine (Pd2Spm); ii) the anti-proliferative activity of Pd2Spm against a triple negative human breast carcinoma (MDA-MB-231); and finally iii) the putative interaction mediated by combination of Pd2Spm with Docetaxel. Anti-invasive (anti-angiogenic and anti-migratory) as well as anti-proliferative capacities were assessed, for different combination schemes and drug exposure times, using the CAM assay and VEGFR2 activity measurement, the MatrigelTM method and the SRB proliferation test. The results thus obtained evidence the ability of Pd2Spm to restrict angiogenesis and cell migration: Pd2Spm induced a marked inhibition of migration (43.8±12.2%), and a higher inhibition of angiogenesis (81.8±4.4% for total length values, at 4 μM) as compared to DTX at the clinical dosage 4x10-2 μM (26.4±14.4%; n = 4 to 11). Combination of Pd2Spm/DTX was more effective as anti-invasive and anti-proliferative than DTX or Pd2Spm in sole administration, which is compatible with the occurrence of synergism: for the anti-angiogenic effect, IC50(Pd2Spm/DTX) = 0.5/0.5x10-2 μM vs IC50(DTX) = 1.7x10-2 μM and IC50(Pd2Spm) = 1.6 μM. In conclusion, the reported effects of Pd2Spm on angiogenesis, migration and proliferation showed that this compound is a promising therapeutic agent against this type of breast cancer. Moreover, combined administration of Pd2Spm and DTX was found to trigger a substantial synergetic effect regarding angiogenesis inhibition as well as anti-migratory and anti-proliferative activities reinforcing the putative use of Pd(II) complexes in chemotherapeutic regimens. This is a significant outcome, aiming at the application of these combined strategies towards metastatic breast cancer (or other type of resistant cancers), justifying further studies that include pre-clinical trials. PMID:27880824

In situ REM and ex situ SPM studies of silicon (111) surface

NASA Astrophysics Data System (ADS)

Aseev, A. L.; Kosolobov, S. S.; Latyshev, A. V.; Song, Se Ahn; Saranin, A. A.; Zotov, A. V.; Lifshits, V. G.

2005-09-01

Combination of experimental methods, including ultrahigh vacuum in situ reflection electron microscopy, scanning tunnelling microscopy and atomic force microscopy, has been applied for analysis of surface structure and dynamic processes on silicon (111) surfaces during sublimation, rapid temperature cooling, oxygen reactions and metal-silicon surface phase formation. From analysis of triangular negative islands, 0.08 nm in depth, which were forming during quenching, it was deduced the effective activation energy of the island generation is equalled to 0.35 eV and made conclusion that the (1 × 1) (7 × 7) phase transition on Si(111) assumes to be responsible for the negative island nucleation. On the base of the in situ REM study, the dependence of step motion, initiated by surface vacancies generation during oxygen-silicon interaction, on the terrace width was measured. Peculiarities of the initial stages of silicon surface oxidation at low pressures were considered. From precision measurements, the top silicon atom density was determined for the metal-silicon surface phase formed during Na, Ca, Mg and Ag deposition on clean silicon (111) surface.

Reagent-free and portable detection of Bacillus anthracis spores using a microfluidic incubator and smartphone microscope.

PubMed

Hutchison, Janine R; Erikson, Rebecca L; Sheen, Allison M; Ozanich, Richard M; Kelly, Ryan T

2015-09-21

Bacillus anthracis is the causative agent of anthrax and can be contracted by humans and herbivorous mammals by inhalation, ingestion, or cutaneous exposure to bacterial spores. Due to its stability and disease potential, B. anthracis is a recognized biothreat agent and robust detection and viability methods are needed to identify spores from unknown samples. Here we report the use of smartphone-based microscopy (SPM) in combination with a simple microfluidic incubation device (MID) to detect 50 to 5000 B. anthracis Sterne spores in 3 to 5 hours. This technique relies on optical monitoring of the conversion of the ∼1 μm spores to the filamentous vegetative cells that range from tens to hundreds of micrometers in length. This distinguishing filament formation is unique to B. anthracis as compared to other members of the Bacillus cereus group. A unique feature of this approach is that the sample integrity is maintained, and the vegetative biomass can be removed from the chip for secondary molecular analysis such as PCR. Compared with existing chip-based and rapid viability PCR methods, this new approach reduces assay time by almost half, and is highly sensitive, specific, and cost effective.

Nanotechnology: Opportunities and Challenges

NASA Technical Reports Server (NTRS)

Meyyappan, Meyya

2003-01-01

Nanotechnology seeks to exploit novel physical, chemical, biological, mechanical, electrical, and other properties, which arise primarily due to the nanoscale nature of certain materials. A key example is carbon nanotubes (CNTs) which exhibit unique electrical and extraordinary mechanical properties and offer remarkable potential for revolutionary applications in electronics devices, computing, and data storage technology, sensors, composites, nanoelectromechanical systems (NEMS), and as tip in scanning probe microscopy (SPM) for imaging and nanolithography. Thus the CNT synthesis, characterization, and applications touch upon all disciplines of science and engineering. This presentation will provide an overview and progress report on this and other major research candidates in Nanotechnology and address opportunities and challenges ahead.

Brillouin Light Scattering from Magnetic Excitations in Superparamagnetic and Ferromagnetic Co-Al-O Granular Films

NASA Astrophysics Data System (ADS)

Yoshihara, Akira; Maeda, Toshiteru; Kawamura, Satoshi; Nakamura, Shintaro; Nojima, Tsutomu; Takeda, Yoshihiko; Ohnuma, Shigehiro

2018-04-01

A systematic study of Brillouin light scattering (BLS) from superparamagnetic (SPM) and ferromagnetic (FM) Co-Al-O granular films was performed under magnetic fields of up to 4.6 kOe in the standard backscattering geometry at room temperature. The SPM and FM boundary, defined as the Co composition at which the exchange field vanishes, was found to be located at xC(Co) = 59.3 ± 1.3 at. %. From FM films we observed a pair of bulk spin-wave peaks on both the positive- and negative-frequency sides and a surface localized Damon-Eshbach peak only on the positive-frequency side under the present scattering conditions. From SPM films, a pair of broader but propagative excitation peaks with asymmetric intensity were observed on both frequency sides in a spectrum. We performed a numerical analysis of the BLS spectrum by employing the theory developed by Camley and Mills (CM) while retaining dipole and exchange couplings for FM films and only dipole coupling for SPM films. The CM theory successfully reproduced the observed spectrum for both SPM and FM films. The SPM spectrum exhibits a singlet-doublet peak structure similarly to an FM SW spectrum. The SPM peak stems from the dipole-coupled larger-amplitude precession motion of the granule magnetic moment around the external-field-induced magnetization.

40 CFR 58.20 - Special purpose monitors (SPM).

Code of Federal Regulations, 2010 CFR

2010-07-01

... Administrator will not base a NAAQS violation determination for the PM2.5 or ozone NAAQS solely on data from the... discontinuation of the monitor as a SLAMS site. (b) Any SPM data collected by an air monitoring agency using a... monitoring agency's data objectives are inconsistent with those requirements. Data collected at an SPM using...

In situ observations of suspended particulate matter plumes at an offshore wind farm, southern North Sea

NASA Astrophysics Data System (ADS)

Baeye, Matthias; Fettweis, Michael

2015-08-01

Suspended particulate matter (SPM) plumes associated with the monopile foundations of the Belgian offshore wind farm (OWF) Belwind I were acoustically profiled by means of a Doppler current profiler (ADCP). Together with the analysis of a bottom lander dataset of optical and acoustic backscatter sensors (OBSs and ADPs respectively), the spatiotemporal SPM plume dynamics were inferred. The fieldwork comprised (1) near-bed measurements of hydrodynamics and SPM concentrations in the direct vicinity of the wind turbines, by means of a bottom lander over a spring-neap cycle in May 2010; this dataset represents a typically tide-driven situation because there was no significant meteorological forcing during the measurement period; (2) additional vessel-based measurements conducted in May 2013 to capture the SPM plumes inside and outside the OWF over part of a tidal cycle. Both in situ datasets revealed that the SPM plumes were generated at the turbine piles, consistent with aerial and space-borne imagery. The SPM plumes are well aligned with the tidal current direction in the wake of the monopiles, concentrations being estimated to reach up to 5 times that of the background concentration of about 3 mg/l. It is suggested that the epifaunal communities colonizing the monopile surface and the protective rock collar at the base play a key role as source of the suspended matter recorded in the plumes. The organisms filter and trap fine SPM from the water column, resulting in predominant accumulation of SPM, including detritus and (pseudo-) faeces, at the base of the piles. When tidal currents exceed a certain velocity, fine particles in the near-bed fluff layer are re-suspended and transported downstream in the wake of the piles.

Holocene provenance shift of suspended particulate matter in the Amazon River basin

NASA Astrophysics Data System (ADS)

Höppner, Natalie; Lucassen, Friedrich; Chiessi, Cristiano M.; Sawakuchi, André O.; Kasemann, Simone A.

2018-06-01

The strontium (Sr), neodymium (Nd) and lead (Pb) isotope signatures of suspended particulate matter (SPM) in rivers reflect the radiogenic isotope signatures of the rivers' drainage basin. These signatures are not significantly affected by weathering, transport or depositional cycles, but document the sedimentary contributions of the respective sources. We report new Sr, Nd and Pb isotope ratios and element concentrations of modern SPM from the Brazilian Amazon River basin and document the past evolution of the basin by analyzing radiogenic isotopes of a marine sediment core from the slope off French Guiana archiving the last 40 kyr of Amazon River SPM, and the Holocene section of sediment cores raised between the Amazon River mouth and the slope off French Guiana. The composition of modern SPM confirms two main source areas, the Andes and the cratonic Shield. In the marine sediment core notable changes occurred during the second phase of Heinrich Stadial 1 (i.e. increased proportion of Shield rivers SPM) and during the last deglaciation (i.e. increased proportion of Madeira River SPM) together with elsewhere constant source contributions. Furthermore, we report a prominent offset in Sr and Nd isotopic composition between the average core value (εNd: -11.7 ± 0.9 (2SD), 87Sr/86Sr: 0.7229 ± 0.0016 (2SD)) and the average modern Amazon River SPM signal (εNd: -10.5 ± 0.5 (2SD), 87Sr/86Sr: 0.7213 ± 0.0036 (2SD)). We suggest that a permanent change in the Amazon River basin sediment supply during the late Holocene to a more Andean dominated SPM was responsible for the offset.

Secondary Primary Malignancy Risk in Patients With Cervical Cancer in Taiwan: A Nationwide Population-Based Study.

PubMed

Teng, Chung-Jen; Huon, Leh-Kiong; Hu, Yu-Wen; Yeh, Chiu-Mei; Chao, Yee; Yang, Muh-Hwa; Chen, Tzeng-Ji; Hung, Yi-Ping; Liu, Chia-Jen

2015-10-01

To evaluate the risk of secondary primary malignancy (SPM) in patients with cervical cancer using a nationwide population-based dataset.Patients newly diagnosed with cervical cancer between 1997 and 2011 were identified using Taiwan's National Health Insurance database. Patients with antecedent malignancies were excluded. Standardized incidence ratios (SIRs) for SPM were calculated by comparing with the cancer incidence in the general population. Risk factors for cancer development were analyzed using Cox proportional hazard models.During the 14-year study period (follow-up of 223,062 person-years), 2004 cancers developed in 35,175 patients with cervical cancer. The SIR for all cancers was 1.56 (95% confidence interval, 1.50-1.63, P < 0.001). SIRs for follow-up periods of >10, 5 to 10, 1 to 5, and <1 year were 1.37, 1.51, 1.34, and 2.59, respectively. After the exclusion of SPM occurring within 1 year of cervical cancer diagnosis, SIRs were significantly higher for cancers of the esophagus (2.05), stomach (1.38), colon, rectum, and anus (1.36); lung and mediastinum (2.28), bone and soft tissue (2.23), uterus (3.76), bladder (2.26), and kidneys (1.41). Multivariate analysis showed that age ≥60 was a significant SPM risk factor (hazard ratio [HR] 1.59). Different treatments for cervical cancer, including radiotherapy (HR 1.41) and chemotherapy (HR 1.27), had different impacts on SPM risk. Carboplatin and fluorouracil independently increased SPM risk in cervical cancer patients.Patients with cervical cancer are at increased risk of SPM development. Age ≥60 years, chemotherapy, and radiotherapy are independent risk factors. Carboplatin and fluorouracil also increased SPM risk independently. Close surveillance of patients at high risk should be considered for the early detection of SPMs.

Testing a Theoretical Model of the Stress Process in Alzheimer's Caregivers with Race as a Moderator

ERIC Educational Resources Information Center

Hilgeman, Michelle M.; Durkin, Daniel W.; Sun, Fei; DeCoster, Jamie; Allen, Rebecca S.; Gallagher-Thompson, Dolores; Burgio, Louis D.

2009-01-01

Purpose: The primary aim of this study was to test the stress process model (SPM; Pearlin, Mullan, Semple, & Skaff, 1990) in a racially diverse sample of Alzheimer's caregivers (CGs) using structural equation modeling (SEM) and regression techniques. A secondary aim was to examine race or ethnicity as a moderator of the relation between latent…

A Partnership Training Program in Breast Cancer Research Using Molecular Imaging Techniques

DTIC Science & Technology

2009-07-01

suggests that the cause of this interaction is the nonuniform toroidal distribution of Magnevist within the NDS, consistent with SEM and nonmagnetic SPM...disease. Ann Neurol 25:450–459 de Leon MJ, DeSanti S, Zinkowski R, Mehta PD, Pratico D, Segal S, Clark C, Kerkman D, DeBernardis J, Li J, Lair L, Reisberg B

NIRS-SPM: statistical parametric mapping for near infrared spectroscopy

NASA Astrophysics Data System (ADS)

Tak, Sungho; Jang, Kwang Eun; Jung, Jinwook; Jang, Jaeduck; Jeong, Yong; Ye, Jong Chul

2008-02-01

Even though there exists a powerful statistical parametric mapping (SPM) tool for fMRI, similar public domain tools are not available for near infrared spectroscopy (NIRS). In this paper, we describe a new public domain statistical toolbox called NIRS-SPM for quantitative analysis of NIRS signals. Specifically, NIRS-SPM statistically analyzes the NIRS data using GLM and makes inference as the excursion probability which comes from the random field that are interpolated from the sparse measurement. In order to obtain correct inference, NIRS-SPM offers the pre-coloring and pre-whitening method for temporal correlation estimation. For simultaneous recording NIRS signal with fMRI, the spatial mapping between fMRI image and real coordinate in 3-D digitizer is estimated using Horn's algorithm. These powerful tools allows us the super-resolution localization of the brain activation which is not possible using the conventional NIRS analysis tools.

Evidence against involvement of the acid lysosomal sphingomyelinase in the tumor-necrosis-factor- and interleukin-1-induced sphingomyelin cycle and cell proliferation in human fibroblasts.

PubMed Central

Andrieu, N; Salvayre, R; Levade, T

1994-01-01

The hydrolysis of sphingomyelin (SPM) has been reported to mediate a number of responses to extracellular agents, including cytokines. The so-called SPM cycle may result from the activation of different types of sphingomyelinases (SPMases). We investigated the hypothetical contribution of acid lysosomal SPMase in the SPM signal-transduction pathway. We examined the ability of human skin fibroblasts with a genetic deficiency of acid lysosomal SPMase activity to respond to tumour necrosis factor alpha (TNF-alpha) or interleukin-1 beta (IL-1 beta). We report that both cytokines promoted SPM hydrolysis in fibroblasts derived from patients with Niemann-Pick disease or I-cell disease, similar to that observed in normal cells. Treatment of normal fibroblasts with cationic amphiphilic drugs resulted in inhibition of acid SPMase activity, but had no effect on cytokine-induced SPM turnover. In addition, TNF-alpha and IL-1 beta stimulated [3H]thymidine incorporation in Niemann-Pick fibroblasts, as in normal cells. Thus our results argue against a role for acid endolysosomal SPMase in mediating the cytokine-induced SPM signalling cascade. Images Figure 2 PMID:7980390

Spontaneous Swallowing Frequency [Has Potential to] Identify Dysphagia in Acute Stroke

PubMed Central

Carnaby, Giselle D; Sia, Isaac; Khanna, Anna; Waters, Michael

2014-01-01

Background and Purpose Spontaneous swallowing frequency has been described as an index of dysphagia in various health conditions. This study evaluated the potential of spontaneous swallow frequency analysis as a screening protocol for dysphagia in acute stroke. Methods In a cohort of 63 acute stroke cases swallow frequency rates (swallows per minute: SPM) were compared to stroke and swallow severity indices, age, time from stroke to assessment, and consciousness level. Mean differences in SPM were compared between patients with vs. without clinically significant dysphagia. ROC analysis was used to identify the optimal threshold in SPM which was compared to a validated clinical dysphagia examination for identification of dysphagia cases. Time series analysis was employed to identify the minimally adequate time period to complete spontaneous swallow frequency analysis. Results SPM correlated significantly with stroke and swallow severity indices but not with age, time from stroke onset, or consciousness level. Patients with dysphagia demonstrated significantly lower SPM rates. SPM differed by dysphagia severity. ROC analysis yielded a threshold of SPM ≤ 0.40 which identified dysphagia (per the criterion referent) with 0.96 sensitivity, 0.68 specificity, and 0.96 negative predictive value. Time series analysis indicated that a 5 to 10 minute sampling window was sufficient to calculate spontaneous swallow frequency to identify dysphagia cases in acute stroke. Conclusions Spontaneous swallowing frequency presents high potential to screen for dysphagia in acute stroke without the need for trained, available personnel. PMID:24149008

The effects of alcohol on plasma lipid mediators of inflammation resolution in patients with Type 2 diabetes mellitus.

PubMed

Barden, Anne; Shinde, Sujata; Phillips, Michael; Beilin, Lawrence; Mas, Emilie; Hodgson, Jonathan M; Puddey, Ian; Mori, Trevor A

2018-06-01

Type 2 diabetes mellitus is characterized by peripheral insulin resistance and low-grade systemic inflammation. Inflammation resolution is recognised as an important process driven by specialised pro-resolving mediators of inflammation (SPMs) and has the potential to moderate chronic inflammation. Alcohol has the potential to affect synthesis of SPMs by altering key enzymes involved in SPM synthesis and may influence ongoing inflammation associated with Type 2 diabetes mellitus. (i) To examine the effects of alcohol consumed as red wine on plasma SPM in men and women with Type 2 diabetes in a randomised controlled trial and (ii) compare baseline plasma SPM levels in the same patients with those of healthy volunteers. Twenty-four patients with Type 2 diabetes mellitus were randomized to a three-period crossover study with men drinking red wine 300 ml/day (∼31 g alcohol/day) and women drinking red wine 230 ml/day (∼24 g alcohol/day), or equivalent volumes of dealcoholized red wine (DRW) or water, each for 4 weeks. The SPM 18-hydroxyeicosapentaenoic acid (18-HEPE), E-series resolvins (Rv) (RvE1-RvE3), 17-hydroxydocosahexaenoic acid (17-HDHA), and D-series resolvins (RvD1, 17R-RvD1, RvD2, RvD5), 14-hydroxydocosahexaenoic acid (14-HDHA) and Maresin 1 were measured at the end of each period. A baseline comparison of plasma SPM, hs CRP, lipids and glucose was made with healthy volunteers. Red wine did not differentially affect any of the SPM measured when compared with DRW or water. Baseline levels of the hs-CRP and the SPM 18-HEPE, 17-HDHA, RvD1 and 17R-RvD1 in patients with Type 2 diabetes mellitus were all significantly elevated compared with healthy controls and remained so after adjusting for age and gender. Moderate alcohol consumption as red wine does not alter plasma SPM in patients with Type 2 diabetes mellitus. The elevation of SPM levels compared with healthy volunteers may be a homeostatic response to counter ongoing inflammation. Copyright © 2018 Elsevier Ltd. All rights reserved.

Trends of Second Primary Malignancy in Patients with Thyroid Cancer: A Population-Based Cohort Study in Israel.

PubMed

Izkhakov, Elena; Barchana, Micha; Liphshitz, Irena; Silverman, Barbara G; Stern, Naftali; Keinan-Boker, Lital

2017-06-01

Thyroid cancer (TC) is the most common endocrine malignancy. TC patients have a good prognosis and a low disease-related mortality rate. Since such patients are often young, they may be at a higher risk for a second primary malignancy (SPM). This study sought to determine the incidence, risk, and types of SPM between 1980 and 2011, and to assess SPM trends over time among Israeli TC patients. Data were derived from the Israel National Cancer Registry. Primary TC patients diagnosed during 1980-2009 were followed up for SPM incidence until December 31, 2011. Standardized incidence ratios (SIRs) of observed to expected SPM (based on the general population rates) were calculated using Poisson regression. Analyses were stratified by time period of initial TC diagnosis (1980-1995 and 1996-2009). A total of 11,538 TC patients were identified. After exclusion of 107 duplicate cases, records of 1032 patients with SPM were analyzed (an SPM incidence of 8.9%). SIRs for all-site SPMs were 1.23 [confidence interval 1.08-1.35] for males and 1.19 [confidence interval 1.10-1.27] for females. SIRs for tumors of the urinary system and prostate were significantly elevated in males, as were SIRs for tumors of the brain, urinary system, breast, and lung in females. Variables associated with increased risk of developing SPMs included a younger age at TC diagnosis, a shorter latency period, being born in Asia/Africa for both sexes, and being born in Israel for females. Compared with the general population, a subanalysis by TC diagnosis during 1980-1995 and 1996-2009 disclosed a higher SPM incidence for the latter time period in males and for both time periods, with a slightly higher SIR for the latter time period in females. The overall risk of SPM in Israeli TC patients was significantly greater for both sexes compared with the general population, thus identifying TC patients as a high-risk group and calling for caretakers to apply specific follow-up guidelines.

Elemental mapping of biological samples using a scanning proton microprobe

NASA Astrophysics Data System (ADS)

Watt, F.; Grime, G. W.

1988-03-01

Elemental mapping using a scanning proton microprobe (SPM) can be a powerful technique for probing trace elements in biology, allowing complex interfaces to be studied in detail, identifying contamination and artefacts present in the specimen, and in certain circumstances obtaining indirect chemical information. Examples used to illustrate the advantages of the technique include the elemental mapping of growing pollen tubes, honey bee brain section, a mouse macrophage cell, human liver section exhibiting primary biliary cirrhosis, and the attack by a mildew fungus on a pea leaf.

Observation of molecular level behavior in molecular electronic junction device

NASA Astrophysics Data System (ADS)

Maitani, Masato

In this dissertation, I utilize AFM based scanning probe measurement and surface enhanced Raman scattering based vibrational spectroscopic analysis to directly characterize topographic, electronic, and chemical properties of molecules confined in the local area of M3 junction to elucidate the molecular level behavior of molecular junction electronic devices. In the introduction, the characterization of molecular electronic devices with different types of metal-molecule-metal (M3) structures based upon self-assembled monolayers (SAMs) is reviewed. A background of the characterization methods I use in this dissertation, conducting probe atomic force microscopy (cp-AFM) and surface enhanced Raman spectroscopy (SERS), is provided in chapter 1. Several attempts are performed to create the ideal top metal contacts on SAMs by metal vapor phase deposition in order to prevent the metal penetration inducing critical defects of the molecular electronic devices. The scanning probe microscopy (SPM), such as cp-AFM, contact mode (c-) AFM and non-contact mode (nc-) AFM, in ultra high vacuum conditions are utilized to study the process of the metal-SAM interface construction in terms of the correlation between the morphological and electrical properties including the metal nucleation and filament generation as a function of the functionalization of long-chain alkane thiolate SAMs on Au. In chapter 2, the nascent condensation process of vapor phase Al deposition on inert and reactive SAMs are studied by SPM. The results of top deposition, penetration, and filament generation of deposited Al are discussed and compared to the results previously observed by spectroscopic measurements. Cp-AFM was shown to provide new insights into Al filament formation which has not been observed by conventional spectroscopic analysis. Additionally, the electronic characteristics of individual Al filaments are measured. Chapter 3 reveals SPM characterization of Au deposition onto --COOH terminated SAMs utilized with strong surface dipole-dipole intermolecular interaction based on hydrogen bonding and ionic bonding potentially preventing the metal penetration. The observed results are discussed with kinetic paths of metal atoms on each SAM including temporal vacancies controlled by the intermolecular interactions in SAM upon the comparison with the spectroscopic results previously reported. The results in chapter 2 and 3 strongly suggests that AFM based characterization technique is powerful tool especially for detecting molecular-size local phenomena in vapor phase metal deposition process, especially, the electric short-circuit filaments growing through SAMs, which may induce critical misinterpretation of M3 junction device properties. In Chapter 4, an altered metal deposition process on inert SAM with using a buffer layer is performed to diminish the kinetic energy of impinging metal atoms. SPM characterization reveals an abrupt metal-SAM interface without any metal penetration. Examined electric characteristics also revealed typical non-resonant tunneling characteristics of long chain alkane thiolate SAMs. In chapter 5, the buffer layer assisted growth process is used to prepare a nano particles-SAM pristine interface on SAMs to control the metal-SAM interaction in order to study the fundamental issue of chemical enhancement mechanism of SERS. Identical Au nanoparticles-SAM-Au M3 structures with different Au-SAM interactions reveal a large discrepancy of enhancement factors of ˜100 attributed to the chemical interaction. In chapter 6, Raman spectroscopy of M3 junction is applied to the characterization of molecular electronics devices. A crossed nanowire junction (X-nWJ) device is employed for in-situ electronic-spectroscopic simultaneous characterization using Raman spectroscopy. A detailed study reveals the multi-probe capability of X-nWJ for in-situ Raman and in-elastic electron tunneling spectroscopy (IETS) as vibrational spectroscopies to diagnose molecular electronic devices. In chapter 7, aniline oligomer (OAn) based redox SAMs are characterized by spectroscopic and microscopic methods under different chemical redox states by reflection absorption infrared spectroscopy (RAIRS), Raman, x-ray photoelectron spectroscopy (XPS), and AFM in order to elucidate the mechanism of electric switching molecular junctions previously reported. Obtained results are discussed in terms of the chemical and geometrical conformations of molecules in closely packed SAM domains. In chapter 8, in-situ Raman spectroscopy and cp-AFM microscopic techniques are applied to study the electric switching characteristics of X-nWJ incorporating OAn based SAM. The results of tunneling current and in-situ Raman spectroscopy are discussed with the conformational change of OAn component. The conductance switching mechanism associated with domain conformation change of OAn SAM is proposed and evaluated based on the results.

Shifting roles of heterotrophy and autotrophy in coral energetics under varying turbidity.

PubMed

Anthony; Fabricius

2000-09-20

Suspended particulate matter (SPM) strongly alters the trophic environment of photosymbiotic aquatic organisms. At high particles loads, phototrophic energy gains can be diminished due to light absorption by suspended particles, and stress from particle abrasion or deposition on tissues. However, energy gains are enhanced if organisms are able to use SPM as a food source. For photosymbiotic benthic suspension feeders, increases in SPM concentrations may require both phototrophic and heterotrophic acclimation to sustain a positive energy balance. This study provides an experimental analysis of the effects of contrasting light and SPM regimes on the energy budget (scope for growth) of two zooxanthellate corals (Goniastrea retiformis and Porites cylindrica). Using a factorial design in a flow-through tank system, corals were exposed for 2 months to shaded and unshaded conditions (equivalent to 3-4 m depth at 4 and 16 mg dry weight SPM l(-1), respectively) and a range of controlled SPM loads with a natural organic content ( approximately 3% w/w). In G. retiformis, rates of particle ingestion were a linear function of SPM concentration within a broad range (1-30 mg dry weight l(-1)). After 2 months of shading, photosynthetic acclimation was significant in G. retiformis, but did not compensate for the reduced light level, as daily respiration exceeded daily photosynthesis. However, in response to the prolonged shading, G. retiformis more than doubled its rate of particle feeding. At high SPM treatments (16 mg dw l(-1)), sediment feeding by this species compensated fully for the 35-47% lower phototrophy in the shaded treatment. Due to both photo- and heterotrophic plasticity, G. retiformis gained tissue and skeletal mass at all experimental levels of light and SPM. In contrast, rates of particle intake by P. cylindrica contributed <10% to the energy budget in shaded and <3% in unshaded conditions. Feeding rates of P. cylindrica were half-saturated at approximately 3 mg dry weight l(-1), and four- to eight-fold lower than those of G. retiformis. Skeletal growth was sustained, but tissue mass and lipid contents declined in shaded and high-SPM treatments, and carbon loss due to shading by SPM was not compensated for by particle feeding. Thus, due to a lack of photo- and heterotrophic plasticity, periods of high turbidity resulted in energy deficiency in P. cylindrica, and high turbidity conditions appeared physiologically unsustainable for this species. This study is the first to show heterotrophic plasticity in a symbiotic coral, and to show that such plasticity can offset stress from high particle loads. It demonstrates that changes in the trophic mode of some coral species are a mechanism for sustaining a positive energy balance in turbid environments, thereby broadening their physiological niche.

Concentration of biologically active polyamines in meat and liver of sheep and lambs after slaughter and their changes in mutton during storage and cooking.

PubMed

Dadáková, Eva; Pelikánová, Tamara; Kalač, Pavel

2011-02-01

Putrescine (PUT), spermidine (SPD) and spermine (SPM) concentrations using a UPLC method, in chilled mutton, lamb and livers 24 h after slaughter were determined. PUT concentrations were quantifiable only in some samples. Mean SPD concentrations were 4-6, 13.5 and 16.8 mg kg-1 in the meats, sheep and lamb livers, respectively. The respective SPM concentrations were 17-25, 128 and 79 mg kg-1. SPD and SPM losses of about one fifth and half of the initial level, respectively, were apparent in mutton loins stored at -18°C for 6 months. Significant losses of SPD and SPM were found in mutton loins stored aerobically, vacuum-packaged or in a modified atmosphere at +2°C. Boiling and stewing of mutton legs caused SPD and SPM losses of about 40% and roasting of about 60% of the initial content. Copyright © 2010 Elsevier Ltd. All rights reserved.

Effectiveness and Usability of the Sensory Processing Measure-Preschool Quick Tips: Data-Driven Intervention Following the Use of the SPM-Preschool in an Early Childhood, Multiple-Case Study

ERIC Educational Resources Information Center

Olson, Carol H.; Henry, Diana A.; Kliner, Ashley Peck; Kyllo, Alissa; Richter, Chelsea Munson; Charley, Jane; Whitcher, Meagan Chapman; Reinke, Katherine Roth; Tysver, Chelsay Horner; Wagner, Lacey; Walworth, Jessica

2016-01-01

This pre- and posttest multiple-case study examined the effectiveness and usability of the Sensory Processing Measure-Preschool Quick Tips (SPM-P QT) by key stakeholders (parents and teachers) for implementing data-driven intervention to address sensory processing challenges. The Sensory Processing Measure-Preschool (SPM-P) was administered as an…

Measurement Scale of the SOLIS Vector Spectromagnetograph

NASA Technical Reports Server (NTRS)

Jones, Harrison P.; Harvey, John W.; Henney, Carl J.; Keller, Christoph U.; Malanushenko, Olena M.

2004-01-01

Longitudinal magnetograms obtained with thc SOLIS Vector Spectromagnetograph (VSM) during a cross-calibration period are compared with similar data from the NASA/NSO Spectromagnetograph (SPM) at the NSO/Kitt Peak Vacuum Telescope as well as with SOHO/MDI and GONG magnetogram. The VSM began observation at the University of Arizona agricultural test site and collaborative observations were obtained with both the VSM and SPM from 2003 Aug 05 through 2003 Sep 21 where the SPM was officially retired. The VSM replaces the SPM and continues the 3O-year NSO/Kitt Peak synoptic magnetogram record. Magnetograms are compared by equating histograms and, for selected examples, by pixel-by-pixel comparison of co-registered images. The VSM was not corrected for polarization crosstalk and was operated without hast guiding. Solar activity was at best moderate during this period. Over the range of observed fields, the VSM magnetograms show greatly improved sensitivity but are otherwise virtually identical with "raw" SPM magnetogram. GONG magnetograms are also closely comparable with the SPM while MDI flux values tend to be stronger by a factor of 1.2 - 1.4. Dependence of the results on seeing will be discussed. Partial funding for this work was provided through Solar and Heliospheric Research Supporting Research and Technology grants from NASA's Office of Space Sciences.

Sinc or Sine? The Band Excitation Method and Energy Dissipation Measurements by SPM

NASA Astrophysics Data System (ADS)

Jesse, Stephen; Kalinin, Sergei

2007-03-01

Quantitative energy dissipation measurements in force-based SPM is the key to understanding fundamental mechanisms of energy transformations on the nanoscale, molecular, and atomic levels. To date, these measurements are invariably based on either phase and amplitude detection in constant frequency mode, or as amplitude detection in frequency-tracking mode. The analysis in both cases implicitly assumes that amplitude is inversely proportional to the Q-factor and is not applicable when the driving force is position dependent, as is the case for virtually all SPM measurements. All current SPM methods sample only a single frequency in the Fourier domain of the system. Thus, only two out of three parameters (amplitude, resonance, and Q) can be determined independently. Here, we developed and implemented a new approach for SPM detection based on the excitation and detection of a signal having a finite amplitude over a selected region in the Fourier domain and allows simultaneous determination of all three parameters. This band excitation method allows acquisition of the local spectral response at a 10ms/pixel rate, compatible with fast imaging, and is illustrated for electromechanical and mechanical imaging and force-distance spectroscopy. The BE method thus represents a new paradigm in SPM, beyond traditional single-frequency excitation.

Improvement of SPM nonlinear limit by chirped duobinary PolSK transmission

NASA Astrophysics Data System (ADS)

Yang, Lixiu; Fan, Jiayu; Wang, Lutang; Huang, Zhaoming

2005-02-01

In today's terrestrial long-haul optical fiber communication systems, high channel powers are required to obtain a large transmission distance with reasonable optical amplifier spacing. In such systems, however, the presence of nonlinear effects such as the self-phase modulation (SPM) and the fiber dispersion as well as their combined effects, called SPM-induced nonlinear limitation or SPM limit, will seriously degrade the system performances in respect of the effective transmission distance and ultimately become a limiting factor in high-speed, long-haul optical fiber transmission.In this paper, a new transmission format: chirped duobinary PolSK transmission, has been proposed to generate a pre-chirped duobianry signal with fixed polarity (either positive or negative), which is modulated by a PolSK modulator. This format is based on a transmitter setup consisting of a duobinary PolSK Modulation transmitter followed by an additional phase modulator. The chirped duobinary PolSK transmission reduces the signal degradation and spectral broadening in the nonlinear regime significantly. Thus it shifts this SPM nonlinear limit to enable more relaxed dispersion compensation at high optical power compared to the conventional duobinary schemes.The simulation results show chirped duobinary PolSK transmission enlarges the dispersion limited transmission distance, increases the dispersion tolerance and overcome the SPM nonlinear limit.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kumar, Pragati, E-mail: pkumar.phy@gmail.com; Agarwal, Avinash; Saxena, Nupur

The influence of swift heavy ion irradiation (SHII) on surface phonon mode (SPM) and green emission in nanocrystalline CdS thin films grown by chemical bath deposition is studied. The SHII of nanocrystalline CdS thin films is carried out using 70 MeV Ni ions. The micro Raman analysis shows that asymmetry and broadening in fundamental longitudinal optical (LO) phonon mode increases systematically with increasing ion fluence. To analyze the role of phonon confinement, spatial correlation model (SCM) is fitted to the experimental data. The observed deviation of SCM to the experimental data is further investigated by fitting the micro Raman spectra usingmore » two Lorentzian line shapes. It is found that two Lorentzian functions (LFs) provide better fitting than SCM fitting and facilitate to identify the contribution of SPM in the observed distortion of LO mode. The behavior of SPM as a function of ion fluence is studied to correlate the observed asymmetry (Γ{sub a}/Γ{sub b}) and full width at half maximum of LO phonon mode and to understand the SHII induced enhancement of SPM. The ion beam induced interstitial and surface state defects in thin films, as observed by photoluminescence (PL) spectroscopy studies, may be the underlying reason for enhancement in SPM. PL studies also show enhancement in green luminescence with increase in ion fluence. PL analysis reveals that the variation in population density of surface state defects after SHII is similar to that of SPM. The correlation between SPM and luminescence and their dependence on ion irradiation fluence is explained with the help of thermal spike model.« less

Intraclonal Genome Stability of the Metallo-β-lactamase SPM-1-producing Pseudomonas aeruginosa ST277, an Endemic Clone Disseminated in Brazilian Hospitals.

PubMed

Nascimento, Ana P B; Ortiz, Mauro F; Martins, Willames M B S; Morais, Guilherme L; Fehlberg, Lorena C C; Almeida, Luiz G P; Ciapina, Luciane P; Gales, Ana C; Vasconcelos, Ana T R

2016-01-01

Carbapenems represent the mainstay therapy for the treatment of serious P. aeruginosa infections. However, the emergence of carbapenem resistance has jeopardized the clinical use of this important class of compounds. The production of SPM-1 metallo-β-lactamase has been the most common mechanism of carbapenem resistance identified in P. aeruginosa isolated from Brazilian medical centers. Interestingly, a single SPM-1-producing P. aeruginosa clone belonging to the ST277 has been widely spread within the Brazilian territory. In the current study, we performed a next-generation sequencing of six SPM-1-producing P. aeruginosa ST277 isolates. The core genome contains 5899 coding genes relative to the reference strain P. aeruginos a PAO1. A total of 26 genomic islands were detected in these isolates. We identified remarkable elements inside these genomic islands, such as copies of the bla SPM-1 gene conferring resistance to carbapenems and a type I-C CRISPR-Cas system, which is involved in protection of the chromosome against foreign DNA. In addition, we identified single nucleotide polymorphisms causing amino acid changes in antimicrobial resistance and virulence-related genes. Together, these factors could contribute to the marked resistance and persistence of the SPM-1-producing P. aeruginosa ST277 clone. A comparison of the SPM-1-producing P. aeruginosa ST277 genomes showed that their core genome has a high level nucleotide similarity and synteny conservation. The variability observed was mainly due to acquisition of genomic islands carrying several antibiotic resistance genes.

Multi-residue determination of the sorption of illicit drugs and pharmaceuticals to wastewater suspended particulate matter using pressurised liquid extraction, solid phase extraction and liquid chromatography coupled with tandem mass spectrometry.

PubMed

Baker, David R; Kasprzyk-Hordern, Barbara

2011-11-04

Presented is the first comprehensive study of drugs of abuse on suspended particulate matter (SPM) in wastewater. Analysis of SPM is crucial to prevent the under-reporting of the levels of analyte that may be present in wastewater. Analytical methods to date analyse the aqueous part of wastewater samples only, removing SPM through the use of filtration or centrifugation. The development of an analytical method to determine 60 compounds on SPM using a combination of pressurised liquid extraction, solid phase extraction and liquid chromatography coupled with tandem mass spectrometry (PLE-SPE-LC-MS/MS) is reported. The range of compounds monitored included stimulants, opioid and morphine derivatives, benzodiazepines, antidepressants, dissociative anaesthetics, drug precursors, and their metabolites. The method was successfully validated (parameters studied: linearity and range, recovery, accuracy, reproducibility, repeatability, matrix effects, and limits of detection and quantification). The developed methodology was applied to SPM samples collected at three wastewater treatment plants in the UK. The average proportion of analyte on SPM as opposed to in the aqueous phase was <5% for several compounds including cocaine, benzoylecgonine, MDMA, and ketamine; whereas the proportion was >10% with regard to methadone, EDDP, EMDP, BZP, fentanyl, nortramadol, norpropoxyphene, sildenafil and all antidepressants (dosulepin, amitriptyline, nortriptyline, fluoxetine and norfluoxetine). Consequently, the lack of SPM analysis in wastewater sampling protocol could lead to the under-reporting of the measured concentration of some compounds. Copyright © 2011 Elsevier B.V. All rights reserved.

Spirosoma spitsbergense sp. nov. and Spirosoma luteum sp. nov., isolated from a high Arctic permafrost soil, and emended description of the genus Spirosoma.

PubMed

Finster, Kai Waldemar; Herbert, Rodney Andrew; Lomstein, Bente Aagaard

2009-04-01

Two pigmented, Gram-negative, non-motile, pleomorphic rod-shaped bacteria (strains SPM-9(T) and SPM-10(T)) were isolated from a permafrost soil collected from the Adventdalen valley, Spitsbergen, northern Norway. A third isolate (strain M5-H2) was recovered from the same soil sample after the sample had been exposed to simulated Martian environmental conditions. The three strains were characterized taxonomically by using a polyphasic approach. Phylogenetic, chemotaxonomic, physiological and morphological analyses demonstrated that the three isolates were most closely related to members of the genus Spirosoma. 16S rRNA gene sequence data indicated that the three isolates could be divided into two clusters: (i) strain SPM-9(T) and (ii) strains SPM-10(T) and M5-H2. This grouping was confirmed by DNA-DNA hybridization experiments. Strains SPM-9(T) and SPM-10(T) exhibited 92 % 16S rRNA gene sequence similarity to both Spirosoma linguale LMG 10896(T) and Spirosoma rigui WPCB 118(T). The major fatty acids present in all three isolates were summed feature 3 (comprising iso-C(15:0) 2-OH and/or C(16 : 1)omega7c; 43.0-48.2 % of the total), C(16 : 1)omega5c (19.1-21.3 %), C(16 : 0) (6.7-7.3 %), iso-C(17 : 0) 3-OH (4.7-6.0 %) and iso-C(15 : 0) (2.6-5.7 %). On the basis of their phenotypic and genotypic characteristics, the new strains are assigned to two novel species of the genus Spirosoma, for which the names Spirosoma spitsbergense sp. nov. and Spirosoma luteum sp. nov. are proposed. The type strain of Spirosoma spitsbergense is SPM-9(T) (=NCIMB 14407(T)=DSM 19989(T)) and the type strain of Spirosoma luteum is SPM-10(T) (=NCIMB 14406(T)=DSM 19990(T)). An emended description of the genus Spirosoma is also proposed.

Tracking Oxygen Vacancies in Thin Film SOFC Cathodes

NASA Astrophysics Data System (ADS)

Leonard, Donovan; Kumar, Amit; Jesse, Stephen; Kalinin, Sergei; Shao-Horn, Yang; Crumlin, Ethan; Mutoro, Eva; Biegalski, Michael; Christen, Hans; Pennycook, Stephen; Borisevich, Albina

2011-03-01

Oxygen vacancies have been proposed to control the rate of the oxygen reduction reaction and ionic transport in complex oxides used as solid oxide fuel cell (SOFC) cathodes [1,2]. In this study oxygen vacancies were tracked, both dynamically and statically, with the combined use of scanned probe microscopy (SPM) and scanning transmission electron microscopy (STEM). Epitaxial films of La 0.8 Sr 0.2 Co O3 (L SC113) and L SC113 / LaSrCo O4 (L SC214) on a GDC/YSZ substrate were studied, where the latter showed increased electrocatalytic activity at moderate temperature. At atomic resolution, high angle annular dark field STEM micrographs revealed vacancy ordering in L SC113 as evidenced by lattice parameter modulation and EELS studies. The evolution of oxygen vacancy concentration and ordering with applied bias and the effects of bias cycling on the SOFC cathode performance will be discussed. Research is sponsored by the of Materials Sciences and Engineering Division, U.S. DOE.

Scanning proton microprobe applied to analysis of individual aerosol particles from Amazon Basin

NASA Astrophysics Data System (ADS)

Gerab, Fábio; Artaxo, Paulo; Swietlicki, Erik; Pallon, Jan

1998-03-01

The development of the Scanning Proton Microprobe (SPM) offers a new possibility for individual aerosol particle studies. The SPM joins Particle Induced X-ray Emission (PIXE) elemental analysis qualities with micrometric spatial resolution. In this work the Lund University SPM facility was used for elemental characterization of individual aerosol particles emitted to the atmosphere in the Brazilian Amazon Basin, during gold mining activities by the so-called "gold shops".

Ultra-flat SPM-broadened spectra in a highly nonlinear fiber using parabolic pulses formed in a fiber Bragg grating

NASA Astrophysics Data System (ADS)

Parmigiani, Francesca; Finot, Christophe; Mukasa, Kazunori; Ibsen, Morten; Roelens, Michael A.; Petropoulos, Periklis; Richardson, David J.

2006-08-01

We propose a new method for generating flat self-phase modulation (SPM)-broadened spectra based on seeding a highly nonlinear fiber (HNLF) with chirp-free parabolic pulses generated using linear pulse shaping in a superstructured fiber Bragg grating (SSFBG). We show that the use of grating reshaped parabolic pulses allows substantially better performance in terms of the extent of SPM-based spectral broadening and flatness relative to conventional hyperbolic secant (sech) pulses. We demonstrate both numerically and experimentally the generation of SPM-broadened pulses centred at 1542 nm with 92% of the pulse energy remaining within the 29 nm 3 dB spectral bandwidth. Applications in spectra slicing and pulse compression are demonstrated.

Electron-beam-induced potentials in semiconductors: calculation and measurement with an SEM/SPM hybrid system

NASA Astrophysics Data System (ADS)

Thomas, Ch; Joachimsthaler, I.; Heiderhoff, R.; Balk, L. J.

2004-10-01

In this work electron-beam-induced potentials are analysed theoretically and experimentally for semiconductors. A theoretical model is developed to describe the surface potential distribution produced by an electron beam. The distribution of generated carriers is calculated using semiconductor equations. This distribution causes a local change in surface potential, which is derived with the help of quasi-Fermi energies. The potential distribution is simulated using the model developed and measured with a scanning probe microscope (SPM) built inside a scanning electron microscope (SEM), for different samples, for different beam excitations and for different cantilever voltages of SPM. In the end, some fields of application are shown where material properties can be determined using an SEM/SPM hybrid system.

The use of nuclear muprobe techniques to study the chemistry of lacustrine sediments and particles

NASA Astrophysics Data System (ADS)

Grime, G. W.; Davison, W.

1993-05-01

The Oxford SPM has been used in two novel studies of lake chemistry: (a) The distribution of dissolved iron in sediment pore waters close to the sediment/water interface has been measured using the novel technique of diffusive equilibration in a thin film (DET). In this technique, which has a spatial resolution of < 1 mm, much less than that of competing techniques (1 cm), a thin layer of polyacrylamide gel is inserted into the sediment and after the rapid equilibration with the pore water, the gel is dried and fixed. The distribution of trace elements can then be measured using mubeam PIXE. Preliminary results have shown for the first time a subsurface maximum of Fe consistent with current theories of Fe dynamics. This paper presents some results obtained using the technique and discusses the limits on resolution and sensitivity, (b) Individual suspended lake particles (predominantly iron oxides and sulphides) have been analysed using point mubeam RBS and PIXE. Of particular interest in this study is the oxidation state of iron rich particles, so RBS with a 1 μm beam was used to determine the Fe: O stoichiometry of single particles. The particles were filtered from a depth of 14 m in Esthwaite Water in the English Lake District and handled in anoxic conditions until evacuation in the SPM sample chamber. Two distinct compositions of iron oxide were determined in clusters of about 5 μm diameter. Analysis by PIXE revealed that FeS was uniformly distributed in the particulate material and that it also contained elevated levels of Cu and Zn. This study was the first to demonstrate directly that discrete clusters of iron oxides are present in black particulate material which is commonly considered to comprise iron sulphides.

[Detection of cerebral hypoperfusion using single photon emission computed tomography image analysis and statistical parametric mapping in patients with Parkinson's disease or progressive supranuclear palsy].

PubMed

Harada, Kengo; Saeki, Hiroshi; Matsuya, Eiji; Okita, Izumi

2013-11-01

We carried out differential diagnosis of brain blood flow images using single-photon emission computed tomography (SPECT) for patients with Parkinson's disease (PD) or progressive supranuclear paralysis (PSP) using statistical parametric mapping (SPM) and to whom we had applied anatomical standardization. We studied two groups and compared brain blood flow images using SPECT (N-isopropyl-4-iodoamphetamine [(123)I] hydrochloride injection, 222 MGq dosage i.v.). A total of 27 patients were studied using SPM: 18 with PD and 9 with PSP; humming bird sign on MRI was from moderate to medium. The decline of brain bloodstream in the PSP group was more notable in the midbrain, near the domain where the humming bird sign was observable, than in the PD group. The observable differences in brain bloodstream decline in the midbrain of PSP and PD patients suggest the potential usefulness of this technique's clinical application to distinction diagnosis.

PET evaluation of late cerebral effect in advanced radiation therapy techniques for cranial base tumors.

PubMed

Alongi, Pierpaolo; Iaccarino, Leonardo; Losa, Marco; Del Vecchio, Antonella; Gerevini, Simonetta; Plebani, Valentina; Di Muzio, Nadia; Mortini, Pietro; Gianolli, Luigi; Perani, Daniela

2018-05-25

Even though the benefits of radiation therapy are well established, it is important to recognize the broad spectrum of radiation-induced changes, particularly in the central nervous system. The possible damage to the brain parenchyma may have clinical consequences and in particular cognitive impairment might be one of the major complication of radiotherapy. To date, no studies have investigated the effects of focal radiation therapy on brain structure and function together with the assessment of their clinical outcomes at a long follow-up. In this prospective study, we evaluated in six patients the possible brain late effects after radiation therapy, using a standardized neuropsychological battery, MRI and 18F-FDG PET using SPM and semi-quantitative methods, in patients affected by cranial base tumors who underwent gamma knife or tomotherapy. Neuropsychological examinations showed no cognitive impairment after the treatment. In all patients, both MRI assessment and 18F-FDG-PET did not reveal any local or distant anatomical and metabolic late effects. The present study support the safety of advanced radiation therapy techniques. 18F-FDG-PET, using SPM and semi-quantitative methods, might be a valuable tool to evaluate the cerebral radiotoxicity in patients treated for brain neoplasms. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Optimized statistical parametric mapping for partial-volume-corrected amyloid positron emission tomography in patients with Alzheimer's disease and Lewy body dementia

NASA Astrophysics Data System (ADS)

Oh, Jungsu S.; Kim, Jae Seung; Chae, Sun Young; Oh, Minyoung; Oh, Seung Jun; Cha, Seung Nam; Chang, Ho-Jong; Lee, Chong Sik; Lee, Jae Hong

2017-03-01

We present an optimized voxelwise statistical parametric mapping (SPM) of partial-volume (PV)-corrected positron emission tomography (PET) of 11C Pittsburgh Compound B (PiB), incorporating the anatomical precision of magnetic resonance image (MRI) and amyloid β (A β) burden-specificity of PiB PET. First, we applied region-based partial-volume correction (PVC), termed the geometric transfer matrix (GTM) method, to PiB PET, creating MRI-based lobar parcels filled with mean PiB uptakes. Then, we conducted a voxelwise PVC by multiplying the original PET by the ratio of a GTM-based PV-corrected PET to a 6-mm-smoothed PV-corrected PET. Finally, we conducted spatial normalizations of the PV-corrected PETs onto the study-specific template. As such, we increased the accuracy of the SPM normalization and the tissue specificity of SPM results. Moreover, lobar smoothing (instead of whole-brain smoothing) was applied to increase the signal-to-noise ratio in the image without degrading the tissue specificity. Thereby, we could optimize a voxelwise group comparison between subjects with high and normal A β burdens (from 10 patients with Alzheimer's disease, 30 patients with Lewy body dementia, and 9 normal controls). Our SPM framework outperformed than the conventional one in terms of the accuracy of the spatial normalization (85% of maximum likelihood tissue classification volume) and the tissue specificity (larger gray matter, and smaller cerebrospinal fluid volume fraction from the SPM results). Our SPM framework optimized the SPM of a PV-corrected A β PET in terms of anatomical precision, normalization accuracy, and tissue specificity, resulting in better detection and localization of A β burdens in patients with Alzheimer's disease and Lewy body dementia.

Spatial-temporal dynamics and sources of total Hg in a hydroelectric reservoir in the Western Amazon, Brazil.

PubMed

Pestana, I A; Bastos, W R; Almeida, M G; de Carvalho, D P; Rezende, C E; Souza, C M M

2016-05-01

Damming rivers to construct hydroelectric reservoirs results in a series of impacts on the biogeochemical Hg cycle. For example, modifying the hydrodynamics of a natural watercourse can result in the suspension and transport of Hg deposits in the water column, which represents an exposure risk for biota. The objective of this study was to evaluate the influences of seasonality on the dispersion of total Hg in the Hydroelectric Power Plant (HPP)-Samuel Reservoir (Porto Velho/Brazil). Sampling campaigns were performed during the three following hydrological periods characteristic of the region: low (Oct/2011), ebbing (May/2012), and high (Feb/2013) water. Sediment profiles, suspended particulate matter (SPM), and aquatic macrophytes (Eicchornia crassipes and Oryza spp.) were collected, and their Hg concentrations and isotopic and elemental C and N signatures were determined. The drainage basin significantly influenced the SPM compositions during all the periods, with a small autochthonous influence from the reservoir during the low water. The highest SPM Hg concentrations inside the reservoir were observed during the high water period, suggesting that the hydrodynamics of this environment favor the suspension of fine SPM, which has a higher Hg adsorption capacity. The Hg concentrations in the sediment profiles were ten times lower than those in the SPM, indicating that large particles with low Hg concentrations were deposited to form the bottom sediment. Hg concentrations were higher in aquatic macrophyte roots than in their leaves and appeared to contribute to the formation of SPM during the low water period. In this environment, Hg transport mainly occurs in SPM from the Jamari River drainage basin, which is the primary source of Hg in this environment.

Effect of flood events on transport of suspended sediments, organic matter and particulate metals in a forest watershed in the Basque Country (Northern Spain).

PubMed

Peraza-Castro, M; Sauvage, S; Sánchez-Pérez, J M; Ruiz-Romera, E

2016-11-01

An understanding of the processes controlling sediment, organic matter and metal export is critical to assessing and anticipating risk situations in water systems. Concentrations of suspended particulate matter (SPM), dissolved (DOC) and particulate (POC) organic carbon and metals (Cu, Ni, Pb, Cr, Zn, Mn, Fe) in dissolved and particulate phases were monitored in a forest watershed in the Basque Country (Northern Spain) (31.5km(2)) over three hydrological years (2009-2012), to evaluate the effect of flood events on the transport of these materials. Good regression was found between SPM and particulate metal concentration, making it possible to compute the load during the twenty five flood events that occurred during the study period at an annual scale. Particulate metals were exported in the following order: Fe>Mn>Zn>Cr>Pb>Cu>Ni. Annual mean loads of SPM, DOC and POC were estimated at 2267t, 104t and 57t, respectively, and the load (kg) of particulate metals at 76 (Ni), 83 (Cu), 135 (Pb), 256 (Cr), 532 (Zn), 1783 (Mn) and 95170 (Fe). Flood events constituted 91%-SPM, 65%-DOC, 71%-POC, 80%-Cu, 85%-Ni, 72%-Pb, 84%-Cr, 74%-Zn, 87%-Mn and 88%-Fe of total load exported during the three years studied. Flood events were classified into three categories according to their capacity for transporting organic carbon and particulate metals. High intensity flood events are those with high transport capacity of SPM, organic carbon and particulate metals. Most of the SPM, DOC, POC and particulate metal load was exported by this type of flood event, which contributed 59% of SPM, 45% of organic carbon and 54% of metals. Copyright © 2016 Elsevier B.V. All rights reserved.

A simple optical model to estimate suspended particulate matter in Yellow River Estuary.

PubMed

Qiu, Zhongfeng

2013-11-18

Distribution of the suspended particulate matter (SPM) concentration is a key issue for analyzing the deposition and erosion variety of the estuary and evaluating the material fluxes from river to sea. Satellite remote sensing is a useful tool to investigate the spatial variation of SPM concentration in estuarial zones. However, algorithm developments and validations of the SPM concentrations in Yellow River Estuary (YRE) have been seldom performed before and therefore our knowledge on the quality of retrieval of SPM concentration is poor. In this study, we developed a new simple optical model to estimate SPM concentration in YRE by specifying the optimal wavelength ratios (600-710 nm)/ (530-590 nm) based on observations of 5 cruises during 2004 and 2011. The simple optical model was attentively calibrated and the optimal band ratios were selected for application to multiple sensors, 678/551 for the Moderate Resolution Imaging Spectroradiometer (MODIS), 705/560 for the Medium Resolution Imaging Spectrometer (MERIS) and 680/555 for the Geostationary Ocean Color Imager (GOCI). With the simple optical model, the relative percentage difference and the mean absolute error were 35.4% and 15.6 gm(-3) respectively for MODIS, 42.2% and 16.3 gm(-3) for MERIS, and 34.2% and 14.7 gm(-3) for GOCI, based on an independent validation data set. Our results showed a good precision of estimation for SPM concentration using the new simple optical model, contrasting with the poor estimations derived from existing empirical models. Providing an available atmospheric correction scheme for satellite imagery, our simple model could be used for quantitative monitoring of SPM concentrations in YRE.

Maximum sinking velocities of suspended particulate matter in a coastal transition zone

NASA Astrophysics Data System (ADS)

Maerz, Joeran; Hofmeister, Richard; van der Lee, Eefke M.; Gräwe, Ulf; Riethmüller, Rolf; Wirtz, Kai W.

2016-09-01

Marine coastal ecosystem functioning is crucially linked to the transport and fate of suspended particulate matter (SPM). Transport of SPM is controlled by, amongst other factors, sinking velocity ws. Since the ws of cohesive SPM aggregates varies significantly with size and composition of the mineral and organic origin, ws exhibits large spatial variability along gradients of turbulence, SPM concentration (SPMC) and SPM composition. In this study, we retrieved ws for the German Bight, North Sea, by combining measured vertical turbidity profiles with simulation results for turbulent eddy diffusivity. We analyzed ws with respect to modeled prevailing dissipation rates ɛ and found that mean ws were significantly enhanced around log10(ɛ (m2 s-3)) ≈ -5.5. This ɛ region is typically found at water depths of approximately 15 to 20 m along cross-shore transects. Across this zone, SPMC declines towards the offshore waters and a change in particle composition occurs. This characterizes a transition zone with potentially enhanced vertical fluxes. Our findings contribute to the conceptual understanding of nutrient cycling in the coastal region which is as follows. Previous studies identified an estuarine circulation. Its residual landward-oriented bottom currents are loaded with SPM, particularly within the transition zone. This retains and traps fine sediments and particulate-bound nutrients in coastal waters where organic components of SPM become remineralized. Residual surface currents transport dissolved nutrients offshore, where they are again consumed by phytoplankton. Algae excrete extracellular polymeric substances which are known to mediate mineral aggregation and thus sedimentation. This probably takes place particularly in the transition zone and completes the coastal nutrient cycle. The efficiency of the transition zone for retention is thus suggested as an important mechanism that underlies the often observed nutrient gradients towards the coast.

How IPCC Science-Policy Interactions Shape Its Policymaker Summaries

NASA Astrophysics Data System (ADS)

Mach, K. J.; Freeman, P. T.; Mastrandrea, M.; Field, C. B.

2016-12-01

Government approval is a defining feature of the Intergovernmental Panel on Climate Change (IPCC) assessment process. In plenary sessions with scientist authors, IPCC member governments discuss and agree each sentence of every report's summary for policymakers (SPM). This consensus-based approval builds joint ownership of scientific knowledge by both scientists and governments. The approval process and its resulting SPM revisions have received extensive attention in published anecdotes and perspectives, but without comprehensive evaluation to date. We present the results of an in-depth analysis of IPCC SPM revisions, providing an evidence basis for understanding a complex science-policy interaction. Revisions resulting from governmental review and approval expand SPMs. SPM text lengthens by 17 to 53% in recent assessment summaries. Political sensitivities and associated failures of consensus have led to prominent exceptions resulting in SPM contractions. Contrasting recent assertions, we find IPCC SPMs to be as readable as other professionally edited assessment summaries, for multiple measures of reading ease. Across metrics, some SPMs, but not all, become more readable through the revision process. We additionally examine each revision in an SPM for which we have deep familiarity. Most of the SPM's revisions occur prior to the in-person government-approval session, and they emphasize different purposes compared to revisions made during the approval session. Revisions prior to the in-person session largely pertain to clarity, scientific rigor, and explanation, whereas the subsequent in-person government-approval revisions place more emphasis on policy relevance, comprehensiveness of examples, and nuances of expert judgment. The value added in the IPCC government-approval process emerges through multiple stages of revision and approval, as scientists and governments together navigate a complex science-policy interaction.

Secondary Primary Malignancy Risk in Patients With Ovarian Cancer in Taiwan: A Nationwide Population-Based Study.

PubMed

Hung, Yi-Ping; Liu, Chia-Jen; Hu, Yu-Wen; Chen, Min-Huang; Li, Chun-Pin; Yeh, Chiu-Mei; Chiou, Tzeon-Jye; Chen, Tzeng-Ji; Yang, Muh-Hwa; Chao, Yee

2015-09-01

To evaluate the incidence of secondary primary malignancy (SPM) in patients with ovarian cancer using a nationwide retrospective population-based dataset. Patients newly diagnosed with ovarian cancer between 1997 and 2010 were identified using Taiwan's National Health Insurance database. Patients with antecedent malignancies were excluded. Standardized incidence ratios (SIRs) for SPM were calculated and compared with the cancer incidence in the general population. Risk factors for cancer development were analyzed using Cox proportional hazard models. Effects of surgery, chemotherapy, and radiotherapy after ovarian cancer diagnosis were regarded as time-dependent variables to prevent immortal time bias. During the 14-year study period (follow-up of 56,214 person-years), 707 cancers developed in 12,127 patients with ovarian cancer. The SIR for all cancers was 2.78 (95% confidence interval 2.58-3.00). SIRs for follow-up periods of >5, 1-5, and <1 year were 1.87, 2.04, and 6.40, respectively. After the exclusion of SPM occurring within 1 year of ovarian cancer diagnosis, SIRs were significantly higher for cancers of the colon, rectum, and anus (2.14); lung and mediastinum (1.58); breast (1.68); cervix (1.65); uterus (7.96); bladder (3.17), and thyroid (2.23); as well as for leukemia (3.98) and others (3.83). Multivariate analysis showed that age ≥ 50 years was a significant SPM risk factor (hazard ratio [HR] 1.60). Different treatments for ovarian cancer, including radiotherapy (HR 2.07) and chemotherapy (HR 1.27), had different impacts on SPM risk. Patients with ovarian cancer are at increased risk of SPM development. Age ≥ 50 years, radiotherapy, and chemotherapy are independent risk factors. Close surveillance of patients at high risk should be considered for the early detection of SPM.

Cotton ACAULIS5 is involved in stem elongation and the plant defense response to Verticillium dahliae through thermospermine alteration.

PubMed

Mo, Huijuan; Wang, Xingfen; Zhang, Yan; Yang, Jun; Ma, Zhiying

2015-11-01

Overexpression of GhACL5 , an ACAULIS5 from cotton, in Arabidopsis increased plant height and T-Spm level. Silencing of GhACL5 in cotton exhibited a dwarf phenotype and reduced resistance to Verticillium dahliae. The Arabidopsis thaliana gene ACAULIS5 (ACL5), for which inactivation causes a defect in stem elongation, encodes thermospermine (T-Spm) synthase. However, limited information is available about improvement in plant height by the overexpression of ACL5 gene, and the biological functions of ACL5 genes in response to biotic stress. Here, this study reports that constitutive expression of the cotton ACL5 gene (GhACL5) in Arabidopsis thaliana significantly increased plant height and elevated the level of T-Spm. Silencing of that gene in cotton reduced the amount of T-Spm and led to a severe dwarf phenotype. Expression of GhACL5 was induced upon treatment with the fungal pathogen Verticillium dahliae and plant hormones salicylic acid, jasmonic acid, and ethylene in resistant cotton plants, but gene silencing in cotton enhanced their susceptibility to V. dahliae infection. Furthermore, T-Spm exposure effectively inhibited V. dahliae growth in vitro. In summary, GhACL5 expression is related to in planta levels of T-Spm and is involved in stem elongation and defense responses against V. dahliae.

Pharmaceuticals in settleable particulate material in urban and non-urban waters.

PubMed

Lahti, Marja; Oikari, Aimo

2011-10-01

Wastewater treatment plants (WWTP) are important sources of settleable particulate material (SPM), heading to sediments with natural suspended solids. To date, there is little information about the fate of pharmaceuticals in sediment systems. In this study, the objective was to determine if pharmaceuticals are detected in SPM at locations near WWTPs or even in rural areas, thus being susceptible for sedimentation. SPM samples were collected from 10 sites in Finland, grouped as reference, rural and wastewater effluent sites. SPM collectors were placed about 35 cm above bottom for about 2 months during summer. After extraction, a set of 17 pharmaceuticals was analyzed. Several pharmaceuticals were detected in SPM accumulated at sites next to WWTPs. The concentration of citalopram was notably high (300-1350 ng g⁻¹ dw). Also bisoprolol and ciprofloxacin were detected at high concentrations (6-325 and 9-390 ng g⁻¹ dw, respectively). In contrast, none of the pharmaceuticals were detected from reference sites and only two were found from a single rural site. There is no previous information about the presence of pharmaceuticals in SPM. The results showed that pharmaceuticals are sorbed to particles in WWTP and nearby, eventually ending up in sediments. These results also indicate that pharmaceuticals are not markedly contaminating sediments of rural areas in Finland. Copyright © 2011 Elsevier Ltd. All rights reserved.

The dynamics of suspended particulate matter (SPM) and chlorophyll-a from intratidal to annual time scales in a coastal turbidity maximum

NASA Astrophysics Data System (ADS)

van der Hout, C. M.; Witbaard, R.; Bergman, M. J. N.; Duineveld, G. C. A.; Rozemeijer, M. J. C.; Gerkema, T.

2017-09-01

The analysis of 1.8 years of data gives an understanding of the response to varying forcing of suspended particulate matter (SPM) and chlorophyll-a (CHL-a) in a coastal turbidity maximum zone (TMZ). Both temporal and vertical concentration variations in the near-bed layer (0-2 m) in the shallow (11 m deep) coastal zone at 1 km off the Dutch coast are shown. Temporal variations in the concentration of both parameters are found on tidal and seasonal scales, and a marked response to episodic events (e.g. storms). The seasonal cycle in the near-bed CHL-a concentration is determined by the spring bloom. The role of the wave climate as the primary forcing in the SPM seasonal cycle is discussed. The tidal current provides a background signal, generated predominantly by local resuspension and settling and a minor role is for advection in the cross-shore and the alongshore direction. We tested the logarithmic Rouse profile to the vertical profiles of both the SPM and the CHL-a data, with respectively 84% and only 2% success. The resulting large percentage of low Rouse numbers for the SPM profiles suggest a mixed suspension is dominant in the TMZ, i.e. surface SPM concentrations are in the same order of magnitude as near-bed concentrations.

A missing link in the estuarine nitrogen cycle?: Coupled nitrification-denitrification mediated by suspended particulate matter.

PubMed

Zhu, Weijing; Wang, Cheng; Hill, Jaclyn; He, Yangyang; Tao, Bangyi; Mao, Zhihua; Wu, Weixiang

2018-02-02

In estuarine and coastal ecosystems, the majority of previous studies have considered coupled nitrification-denitrification (CND) processes to be exclusively sediment based, with little focus on suspended particulate matter (SPM) in the water column. Here, we present evidence of CND processes in the water column of Hangzhou Bay, one of the largest macrotidal embayments in the world. Spearman's correlation analysis showed that SPM was negatively correlated with nitrate (rho = -0.372, P = 0.018) and marker genes for nitrification and denitrification in the water column were detected by quantitative PCR analysis. The results showed that amoA and nir gene abundances strongly correlated with SPM (all P < 0.01) and the ratio of amoA/nir strongly correlated with nitrate (rho = -0.454, P = 0.003). Furthermore, aggregates consisting of nitrifiers and denitrifiers on SPM were also detected by fluorescence in situ hybridization. Illumina MiSeq sequencing further showed that ammonia oxidizers mainly belonged to the genus Nitrosomonas, while the potential denitrifying genera Bradyrhizobium, Comamonas, Thauera, Stenotrophomonas, Acinetobacter, Anaeromyxobacter, Sulfurimonas, Paenibacillus and Sphingobacterium showed significant correlations with SPM (all P < 0.01). This study suggests that SPM may provide a niche for CND processes to occur, which has largely been missing from our understanding of nitrogen cycling in estuarine waters.

Estimation of suspended particulate matter in turbid coastal waters: application to hyperspectral satellite imagery.

PubMed

Zhao, Jun; Cao, Wenxi; Xu, Zhantang; Ye, Haibin; Yang, Yuezhong; Wang, Guifen; Zhou, Wen; Sun, Zhaohua

2018-04-16

An empirical algorithm is proposed to estimate suspended particulate matter (SPM) ranging from 0.675 to 25.7 mg L -1 in the turbid Pearl River estuary (PRE). Comparisons between model predicted and in situ measured SPM resulted in R 2 s of 0.97 and 0.88 and mean absolute percentage errors (MAPEs) of 23.96% and 29.69% by using the calibration and validation data sets, respectively. The developed algorithm demonstrated the highest accuracy when compared with existing ones for turbid coastal waters. The diurnal dynamics of SPM was revealed by applying the proposed algorithm to reflectance data collected by a moored buoy in the PRE. The established algorithm was implemented to Hyperspectral Imager for the Coastal Ocean (HICO) data and the distribution pattern of SPM in the PRE was elucidated. Validation of HICO-derived reflectance data by using concurrent MODIS/Aqua data as a benchmark indicated their reliability. Factors influencing variability of SPM in the PRE were analyzed, which implicated the combined effects of wind, tide, rainfall, and circulation as the cause.

Nanoscale deformation measurements for reliability assessment of material interfaces

NASA Astrophysics Data System (ADS)

Keller, Jürgen; Gollhardt, Astrid; Vogel, Dietmar; Michel, Bernd

2006-03-01

With the development and application of micro/nano electronic mechanical systems (MEMS, NEMS) for a variety of market segments new reliability issues will arise. The understanding of material interfaces is the key for a successful design for reliability of MEMS/NEMS and sensor systems. Furthermore in the field of BIOMEMS newly developed advanced materials and well known engineering materials are combined despite of fully developed reliability concepts for such devices and components. In addition the increasing interface-to volume ratio in highly integrated systems and nanoparticle filled materials are challenges for experimental reliability evaluation. New strategies for reliability assessment on the submicron scale are essential to fulfil the needs of future devices. In this paper a nanoscale resolution experimental method for the measurement of thermo-mechanical deformation at material interfaces is introduced. The determination of displacement fields is based on scanning probe microscopy (SPM) data. In-situ SPM scans of the analyzed object (i.e. material interface) are carried out at different thermo-mechanical load states. The obtained images are compared by grayscale cross correlation algorithms. This allows the tracking of local image patterns of the analyzed surface structure. The measurement results are full-field displacement fields with nanometer resolution. With the obtained data the mixed mode type of loading at material interfaces can be analyzed with highest resolution for future needs in micro system and nanotechnology.

A Tapered Aluminium Microelectrode Array for Improvement of Dielectrophoresis-Based Particle Manipulation

PubMed Central

Buyong, Muhamad Ramdzan; Larki, Farhad; Faiz, Mohd Syafiq; Hamzah, Azrul Azlan; Yunas, Jumrail; Majlis, Burhanuddin Yeop

2015-01-01

In this work, the dielectrophoretic force (FDEP) response of Aluminium Microelectrode Arrays with tapered profile is investigated through experimental measurements and numerical simulations. A standard CMOS processing technique with a step for the formation of a tapered profile resist is implemented in the fabrication of Tapered Aluminium Microelectrode Arrays (TAMA). The FDEP is investigated through analysis of the Clausius-Mossotti factor (CMF) and cross-over frequency (fxo). The performance of TAMA with various side wall angles is compared to that of microelectrodes with a straight cut sidewall profile over a wide range of frequencies through FEM numerical simulations. Additionally, electric field measurement (EFM) is performed through scanning probe microscopy (SPM) in order to obtain the region of force focus in both platforms. Results showed that the tapered profile microelectrodes with angles between 60° and 70° produce the highest electric field gradient on the particles. Also, the region of the strongest electric field in TAMA is located at the bottom and top edge of microelectrode while the strongest electric field in microelectrodes with straight cut profile is found at the top corner of the microelectrode. The latter property of microelectrodes improves the probability of capturing/repelling the particles at the microelectrode’s side wall. PMID:25970255

A tapered aluminium microelectrode array for improvement of dielectrophoresis-based particle manipulation.

PubMed

Buyong, Muhamad Ramdzan; Larki, Farhad; Faiz, Mohd Syafiq; Hamzah, Azrul Azlan; Yunas, Jumrail; Majlis, Burhanuddin Yeop

2015-05-11

In this work, the dielectrophoretic force (F(DEP)) response of Aluminium Microelectrode Arrays with tapered profile is investigated through experimental measurements and numerical simulations. A standard CMOS processing technique with a step for the formation of a tapered profile resist is implemented in the fabrication of Tapered Aluminium Microelectrode Arrays (TAMA). The F(DEP) is investigated through analysis of the Clausius-Mossotti factor (CMF) and cross-over frequency (f(xo)). The performance of TAMA with various side wall angles is compared to that of microelectrodes with a straight cut sidewall profile over a wide range of frequencies through FEM numerical simulations. Additionally, electric field measurement (EFM) is performed through scanning probe microscopy (SPM) in order to obtain the region of force focus in both platforms. Results showed that the tapered profile microelectrodes with angles between 60° and 70° produce the highest electric field gradient on the particles. Also, the region of the strongest electric field in TAMA is located at the bottom and top edge of microelectrode while the strongest electric field in microelectrodes with straight cut profile is found at the top corner of the microelectrode. The latter property of microelectrodes improves the probability of capturing/repelling the particles at the microelectrode's side wall.

Linking water quality guidelines to the natural characteristics of catchments in order to support distinct aquatic ecosystems: Water quality guidelines for suspended particulate matter

NASA Astrophysics Data System (ADS)

Bilotta, G. S.; Grove, M. K.; Harrison, C.; Joyce, C. B.; Peacock, C.

2012-12-01

The natural characteristics of a catchment provide a template that controls the background rates of geomorphological processes operating within that catchment, which in-turn determines the background physico-chemical and hydro-morphological characteristics of the catchment's surface waters. Large differences in the natural characteristics of catchments (e.g. geology, topography, climate), lead to unique physico-chemical and hydro-morphological conditions that support unique freshwater communities. However, this uniqueness is not always recognised in international water quality guidelines, which often attempt to apply blanket water-quality guidelines to 'protect' a wide range of ecosystems. In this paper we investigate the natural characteristics that control background concentrations of suspended particulate matter (SPM - including nano-scale particles to sand-sized sediments), which is a well-known cause of ecological degradation. At present, the management of SPM is hampered by a lack of understanding of the SPM conditions that water quality managers should aim to achieve in contrasting environments in order to support good ecological status. To address this, in this paper we examine the SPM preferences of contrasting biological communities that are in reference condition (minimal anthropogenic disturbance and high ecological status). We analyse historical SPM data collected on a monthly basis from a wide range of reference-condition temperate environments (638 stream/river sites comprising 42 different biological community-types). This analysis reveals that there are statistically significant differences (One-way ANOVA p < 0.001) between the background SPM concentrations observed in contrasting communities that are in reference condition. Mean background SPM concentrations for contrasting communities ranged from 1.7 to 26.2 mg L-1 (i.e. more than a 15-fold difference). We propose a model for predicting environment-specific water quality guidelines for SPM. In order to develop this model, the 638 reference-condition sites were first classified into one of five mean background SPM ranges (0.00-5.99, 6.00-11.99, 12.00-17.99, 18.00-23.99 and >24.00 mg L-1). Stepwise Multiple Discriminant Analysis (MDA) of these ranges showed that a site's SPM range can be predicted as a function of: mean annual air temperature, mean annual precipitation, mean altitude of upstream catchment, distance from source, slope to source, channel width and depth, the percentage of catchment area comprised of clay, chalk, and hard rock solid geology, and the percentage of the catchment area comprised of blown sand/landslide material as the surface (drift) material. Although the model is still being improved and developed, this research highlights the need to link water quality guidelines to the natural characteristics of catchments and the physico-chemical preferences of the biological communities that would naturally inhabit them.

Bounds on the cross-correlation functions of state m-sequences

NASA Astrophysics Data System (ADS)

Woodcock, C. F.; Davies, Phillip A.; Shaar, Ahmed A.

1987-03-01

Lower and upper bounds on the peaks of the periodic Hamming cross-correlation function for state m-sequences, which are often used in frequency-hopped spread-spectrum systems, are derived. The state position mapped (SPM) sequences of the state m-sequences are described. The use of SPM sequences for OR-channel code division multiplexing is studied. The relation between the Hamming cross-correlation function and the correlation function of SPM sequence is examined. Numerical results which support the theoretical data are presented.

Relevant Optical Issues of the SPM-Twin Telescopes

NASA Astrophysics Data System (ADS)

González, J. J.; Orlov, V.

2007-06-01

Most technical aspects of the SPM-Twin Telescopes have been basically solved by the Magellan and MMT projects. However, the Spectroscopic "Wide Field Telescope" will be the first of its kind and an optical solution based on Magellan needs to be further investigated. In addition, the requirements for adaptive optics for the Standard Field Telescope need to be worked out. In this contribution we will compare optical wide field conceptual designs and the potential scope of AO for SPM-Twin.

Spatial and temporal distribution of metals in suspended particulate matter of the Kali estuary, India

NASA Astrophysics Data System (ADS)

Suja, S.; Kessarkar, Pratima M.; Fernandes, Lina L.; Kurian, Siby; Tomer, Arti

2017-09-01

Major (Al, Fe, Mn, Ti, Mg) and trace (Cu, Zn, Pb, Cr, Ni, Co, Zr, Rb, Sr, Ba, Li, Be, Sc, V, Ga, Nb, Mo, Sn, Sb, Cs, Hf, Ta, Bi, Th, U) elements and particulate organic carbon (POC) concentrations in surface suspended particulate matter (SPM) of the Kali estuary, (central west coast of India) were studied during the pre-monsoon, monsoon and post monsoon seasons to infer estuarine processes, source of SPM and Geoaccumulation Index (Igeo) assigned pollutionIgeo levels. Distribution of SPM indicates the presence of the estuarine turbidity maximum (ETM) during all three seasons near the river mouth and a second ETM during the post monsoon time in the upstream associated with salinities gradient. The SPM during the monsoon is finer grained (avg. 53 μm), characterized by uniformly low normalized elemental concentration, whereas the post and pre monsoon are characterized by high normalized elemental concentration with coarser grain size (avg. 202 μm and 173 μm respectively) with highest ratios in the upstream estuary. The elemental composition and principal component analysis for the upstream estuary SPM support more contribution from the upstream catchment area rocks during the monsoon season; there is additional contribution from the downstream catchment area during the pre and post monsoon period due to the tidal effect. The Kali estuarine SPM has higher Al, Fe, Mn, Ti, Mg, Ni, Co, Ba, Li and V with respect to Average World River SPM (WRSPM). Igeo values for the SPM indicate Kali Estuary to be severely enriched with Mn and moderately enriched with Cu, Zn, Ni, Co, U and Mo in the upstream estuary during pre and post monsoon seasons. Seasonal changes in salinity gradient (reduced freshwater flow due to closing of the dam gates), reduced velocity at meandering region of the estuary and POC of 1.6-2.3% resulted in co-precipitation of trace elements that were further fortified by flocculation and coagulation throughout the water column resulting in metal trapping in the upstream region.

Uptake and degradation of several pyrenesphingomyelins by skin fibroblasts from control subjects and patients with Niemann-Pick disease. Effect of the structure of the fluorescent fatty acyl residue.

PubMed Central

Levade, T; Gatt, S; Salvayre, R

1991-01-01

Three fluorescent analogues of sphingomyelin (SPM), each containing pyrene in the fatty acyl residue, were synthesized and employed for the study of their mode of uptake by, and degradation within, intact cultured human skin fibroblasts. These were prepared by condensing sphingosylphosphocholine and the following fatty acids: pyrenedodecanoic acid (P12), pyrenesulphonylaminoundecanoic acid (PSA11) and pyrenepropenoic acid (P3:1). The cell association and catabolism of these SPM analogues by normal, Niemann-Pick-disease-Type-A and low-density-lipoprotein (LDL)-receptor-negative familial hypercholesterolaemia fibroblasts were investigated and compared with the metabolism of [cholinemethyl-14C]sphingomyelin. The catabolism of the fluorescent derivatives was monitored by measuring the appearance of the corresponding fluorescent ceramides. Two modes of uptake and degradation patterns were observed. Thus P12-SPM and radiolabelled SPM were taken up by LDL-receptor-mediated endocytosis when incubated with serum-containing medium, this conclusion being supported by the very low uptake by familial-hypercholesterolaemia fibroblasts, which lack the apolipoprotein-B/E receptor. After uptake, these compounds were metabolically degraded solely by the lysosomal sphingomyelinase, as evidenced by the fact that more than 98% of the SPM remained undegraded in Niemann-Pick-disease cells. By contrast, PSA11- and P3:1-SPMs were taken up by a receptor-independent endocytic pathway, as indicated by the similar rates of uptake in control and familial-hypercholesterolaemia cells in the absence or presence of fetal-calf serum in the culture medium. The degradation of PSA11-SPM and P3:1-SPM was brought about, in the main, by the lysosomal sphingomyelinase, but also by a yet uncharacterized process. The latter catabolic pathway, active in Niemann-Pick-disease-Type-A fibroblasts, seems to differ from the neutral Mg2(+)-dependent sphingomyelinase whose activity was undetectable in homogenates of skin fibroblasts. The present study emphasizes the influence of the structure of the fatty acyl moiety of SPM on its association with lipoproteins and/or cell membranes and on its intracellular routing and metabolic degradation. Images Fig. 2. PMID:2018477

Sources and distributions of branched and isoprenoid tetraether lipids on the Amazon shelf and fan: Implications for the use of GDGT-based proxies in marine sediments

NASA Astrophysics Data System (ADS)

Zell, Claudia; Kim, Jung-Hyun; Hollander, David; Lorenzoni, Laura; Baker, Paul; Silva, Cleverson Guizan; Nittrouer, Charles; Sinninghe Damsté, Jaap S.

2014-08-01

Branched glycerol dialkyl glycerol tetraethers (brGDGTs) in river fan sediments have been used successfully to reconstruct mean annual air temperature (MAAT) and soil pH of the Congo River drainage basin. However, in a previous study of Amazon deep-sea fan sediments the reconstructed MAATs were ca. 10 °C colder than the actual MAAT of the Amazon basin. In this study we investigated this apparent offset, by comparing the concentrations and distributions of brGDGTs in Amazon River suspended particulate matter (SPM) and sediments to those in marine SPM and surface sediments. The riverine brGDGT input was evident from the elevated brGDGT concentrations in marine SPM and surface sediments close to the river mouth. The distributions of brGDGTs in marine SPM and sediments varied widely, but generally showed a higher relative abundance of methylated and cyclic brGDGTs than those in the river. Since this difference in brGDGT distribution was also found in intact polar lipid (IPL)-derived brGDGTs, which were more recently produced, the change in the marine brGDGT distribution was most likely due to marine in situ production. Consequently, the MAATs calculated based on the methylation of branched tetraethers (MBT) and the cyclisation of branched tetraethers (CBT) were lower and the CBT-derived pH values were higher than those of the Amazon basin. However, SPM and sediments from stations close to the river mouth still showed MBT/CBT values that were similar to those of the river. Therefore, we recommend caution when applying the MBT/CBT proxy, it should only be used in sediment cores that were under high river influence. The influence of riverine derived isoprenoid GDGT (isoGDGT) on the isoGDGT-based TEX86 temperature proxy was also examined in marine SPM and sediments. An input of riverine isoGDGTs from the Amazon River was apparent, but its influence on the marine TEX86 was minor since the TEX86 of SPM in the Amazon River was similar to that in the marine SPM and sediments.

Rapid inactivation of the maize transposable element En/Spm in Medicago truncatula.

PubMed

d'Erfurth, I; Cosson, V; Eschstruth, A; Rippa, S; Messinese, E; Durand, P; Trinh, H; Kondorosi, A; Ratet, P

2003-09-01

Transposable elements have been widely used as mutagens in many organisms. Among them, the maize transposable element En/Spm has been shown to transpose efficiently in several plant species including the model plant Arabidopsis, where it has been used for large-scale mutagenesis. To determine whether we could use this transposon as a mutagen in the model legume plant Medicago truncatula, we tested the activity of the autonomous element, as well as two defective elements, in this plant, and in Arabidopsis as a positive control. In agreement with previous reports, we observed efficient excision of the autonomous En/Spm element in A. thaliana. This element was also active in M. truncatula, but the transposition activity was low and was apparently restricted to the tissue culture step necessary for the production of transgenic plants. The activity of one of the defective transposable elements, dSpm, was very low in A. thaliana and even lower in M. truncatula. The use of different sources of transposases suggested that this defect in transposition was associated with the dSpm element itself. Transposition of the other defective element, I6078, was also detected in M. truncatula, but, as observed with the autonomous element, transposition events were very rare and occurred during tissue culture. These results suggest that the En/Spm element is rapidly inactivated in the regenerated plants and their progeny, and therefore is not suitable for routine insertion mutagenesis in M. truncatula.

Human Milk Proresolving Mediators Stimulate Resolution of Acute Inflammation

PubMed Central

Dalli, Jesmond; Serhan, Charles N

2015-01-01

Human milk contains nutrients and bioactive products relevant to infant development and immunological protection. Here, we investigated the pro-resolving properties of milk using human milk lipid mediator isolates (HLMI) and determined their impact on resolution programs in vivo and with human macrophages. HLMI reduced maximum neutrophil numbers (14.6±1.2×106 to 11.0±1.0×106 cells/exudate) and shortened the resolution interval (Ri; 50% neutrophil reduction) 54% compared to peritonitis. Using rigorous liquid-chromatography tandem-mass spectrometry (LC-MS-MS)-based lipid mediator (LM) metabololipidomics, we demonstrated that human milk possesses a proresolving LM-SPM signature profile, containing specialized proresolving mediators (SPM; e.g. resolvins, protectins, maresins and lipoxins) at bioactive levels (pico-nanomolar concentrations) that enhanced human macrophage efferocytosis and bacterial containment. SPM identified in human milk included D-series resolvins, (e.g. Resolvin (Rv) D1, RvD2, RvD3, AT-RvD3 and RvD4), Protectin (PD)1, Maresin (MaR)1, E-series resolvins (e.g. RvE1, RvE2 and RvE3) and lipoxins (LXA4 and LXB4). Of the SPM identified in human milk, RvD2 and MaR1 (50 ng/mouse) individually shortened Ri ~75%. Milk from mastitis gave higher LTB4 and prostanoids and lower SPM levels. Taken together, these findings provide evidence that human milk has pro-resolving actions via comprehensive LM-SPM profiling, describing a potentially novel mechanism in maternal-infant biochemical imprinting. PMID:26462421

Spontaneous swallowing frequency has potential to identify dysphagia in acute stroke.

PubMed

Crary, Michael A; Carnaby, Giselle D; Sia, Isaac; Khanna, Anna; Waters, Michael F

2013-12-01

Spontaneous swallowing frequency has been described as an index of dysphagia in various health conditions. This study evaluated the potential of spontaneous swallow frequency analysis as a screening protocol for dysphagia in acute stroke. In a cohort of 63 acute stroke cases, swallow frequency rates (swallows per minute [SPM]) were compared with stroke and swallow severity indices, age, time from stroke to assessment, and consciousness level. Mean differences in SPM were compared between patients with versus without clinically significant dysphagia. Receiver operating characteristic curve analysis was used to identify the optimal threshold in SPM, which was compared with a validated clinical dysphagia examination for identification of dysphagia cases. Time series analysis was used to identify the minimally adequate time period to complete spontaneous swallow frequency analysis. SPM correlated significantly with stroke and swallow severity indices but not with age, time from stroke onset, or consciousness level. Patients with dysphagia demonstrated significantly lower SPM rates. SPM differed by dysphagia severity. Receiver operating characteristic curve analysis yielded a threshold of SPM≤0.40 that identified dysphagia (per the criterion referent) with 0.96 sensitivity, 0.68 specificity, and 0.96 negative predictive value. Time series analysis indicated that a 5- to 10-minute sampling window was sufficient to calculate spontaneous swallow frequency to identify dysphagia cases in acute stroke. Spontaneous swallowing frequency presents high potential to screen for dysphagia in acute stroke without the need for trained, available personnel.

Effect of including sweet potato (Ipomoea batatas Lam) meal in finishing pig diets on growth performance, carcass traits and pork quality.

PubMed

Pietrosemoli, Silvana; Moron-Fuenmayor, Oneida Elizabeth; Paez, Angel; Villamide, Maria Jesús

2016-10-01

The partial replacement of a commercial concentrate at 10-20% and 15-30% (the first percentage of each dietary treatment corresponded to weeks 1-3 and the second to weeks 4-7 of the experiment, respectively) by sweet potato meal (SPM; 70% foliage: 30% roots) was evaluated for growth performance, carcass yield, instrumental and sensory pork quality using 36 commercial crossbred pigs (56.8 ± 1.3 kg initial body weight). Three dietary treatments were compared in a randomized complete block design. Most growth, carcass traits and pork quality variables were not affected by the SPM inclusion. Growth performance averaged 868 g/day and feed efficiency 0.24 kg/kg. However, feed intake increased 2.2% (P = 0.04) in pigs fed the 10-20% SPM diets, in a similar order of magnitude as the decrease in dietary energy. Despite an increase in gastrointestinal tract as a percent of hot carcass weight (+14.7%) (P = 0.03) with SPM inclusion, carcass yield averaged 69.4%. Conversely, decreases in loin yield (-4.2%) (P = 0.05), backfat thickness (-6.0%) (P < 0.01) and pork tenderness (-13%) (P = 0.02) were observed with 15-30% SPM inclusion. Results suggest that up to 20% SPM inclusion is a viable feed strategy for finishing pigs, easily replicable in small farm settings. © 2016 Japanese Society of Animal Science. © 2016 Japanese Society of Animal Science.

A multistage crucible of revision and approval shapes IPCC policymaker summaries.

PubMed

Mach, Katharine J; Freeman, Patrick T; Mastrandrea, Michael D; Field, Christopher B

2016-08-01

Intergovernmental Panel on Climate Change (IPCC) member governments approve each report's summary for policymakers (SPM) by consensus, discussing and agreeing on each sentence in a plenary session with scientist authors. A defining feature of IPCC assessment, the governmental approval process builds joint ownership of current knowledge by scientists and governments. The resulting SPM revisions have been extensively discussed in anecdotes, interviews, and perspectives, but they have not been comprehensively analyzed. We provide an in-depth evaluation of IPCC SPM revisions, establishing an evidential basis for understanding their nature. Revisions associated with governmental review and approval generally expand SPMs, with SPM text growing by 17 to 53% across recent assessment reports. Cases of high political sensitivity and failure to reach consensus are notable exceptions, resulting in SPM contractions. In contrast to recent claims, we find that IPCC SPMs are as readable, for multiple metrics of reading ease, as other professionally edited assessment summaries. Across reading-ease metrics, some SPMs become more readable through governmental review and approval, whereas others do not. In an SPM examined through the entire revision process, most revisions associated with governmental review and approval occurred before the start of the government-approval plenary session. These author revisions emphasize clarity, scientific rigor, and explanation. In contrast, the subsequent plenary revisions place greater emphasis especially on policy relevance, comprehensiveness of examples, and nuances of expert judgment. Overall, the value added by the IPCC process emerges in a multistage crucible of revision and approval, as individuals together navigate complex science-policy terrain.

The Applications of Modern Nanoindentation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van Buskirk, Caleb Griffith

2017-03-16

The TI-950 TriboIndenter is a nanoindentation device that obtains nanometer resolution material topography images using Scanning Probe Microscopy (SPM), modulus maps of material using nano-Dynamic Mechanical Analysis, and provides hardness measurements with a resolution of 0.2 nm. The instrument applies a force to a material through a sharp tip and used a transducer to measure the force a material applies back to the tip to derive information about the material. The information can be used to study the homogeneity of material surfaces as well as the homogeneity of the material as a function of depth and can lead to importantmore » information on the aging of the material as well as the consistency of the production of the material.« less

Using SPM 12’s Second-Level Bayesian Inference Procedure for fMRI Analysis: Practical Guidelines for End Users

PubMed Central

Han, Hyemin; Park, Joonsuk

2018-01-01

Recent debates about the conventional traditional threshold used in the fields of neuroscience and psychology, namely P < 0.05, have spurred researchers to consider alternative ways to analyze fMRI data. A group of methodologists and statisticians have considered Bayesian inference as a candidate methodology. However, few previous studies have attempted to provide end users of fMRI analysis tools, such as SPM 12, with practical guidelines about how to conduct Bayesian inference. In the present study, we aim to demonstrate how to utilize Bayesian inference, Bayesian second-level inference in particular, implemented in SPM 12 by analyzing fMRI data available to public via NeuroVault. In addition, to help end users understand how Bayesian inference actually works in SPM 12, we examine outcomes from Bayesian second-level inference implemented in SPM 12 by comparing them with those from classical second-level inference. Finally, we provide practical guidelines about how to set the parameters for Bayesian inference and how to interpret the results, such as Bayes factors, from the inference. We also discuss the practical and philosophical benefits of Bayesian inference and directions for future research. PMID:29456498

Assessing age-related gray matter decline with voxel-based morphometry depends significantly on segmentation and normalization procedures

PubMed Central

Callaert, Dorothée V.; Ribbens, Annemie; Maes, Frederik; Swinnen, Stephan P.; Wenderoth, Nicole

2014-01-01

Healthy ageing coincides with a progressive decline of brain gray matter (GM) ultimately affecting the entire brain. For a long time, manual delineation-based volumetry within predefined regions of interest (ROI) has been the gold standard for assessing such degeneration. Voxel-Based Morphometry (VBM) offers an automated alternative approach that, however, relies critically on the segmentation and spatial normalization of a large collection of images from different subjects. This can be achieved via different algorithms, with SPM5/SPM8, DARTEL of SPM8 and FSL tools (FAST, FNIRT) being three of the most frequently used. We complemented these voxel based measurements with a ROI based approach, whereby the ROIs are defined by transforms of an atlas (containing different tissue probability maps as well as predefined anatomic labels) to the individual subject images in order to obtain volumetric information at the level of the whole brain or within separate ROIs. Comparing GM decline between 21 young subjects (mean age 23) and 18 elderly (mean age 66) revealed that volumetric measurements differed significantly between methods. The unified segmentation/normalization of SPM5/SPM8 revealed the largest age-related differences and DARTEL the smallest, with FSL being more similar to the DARTEL approach. Method specific differences were substantial after segmentation and most pronounced for the cortical structures in close vicinity to major sulci and fissures. Our findings suggest that algorithms that provide only limited degrees of freedom for local deformations (such as the unified segmentation and normalization of SPM5/SPM8) tend to overestimate between-group differences in VBM results when compared to methods providing more flexible warping. This difference seems to be most pronounced if the anatomy of one of the groups deviates from custom templates, a finding that is of particular importance when results are compared across studies using different VBM methods. PMID:25002845

High reliability linear drive device for artificial hearts

NASA Astrophysics Data System (ADS)

Ji, Jinghua; Zhao, Wenxiang; Liu, Guohai; Shen, Yue; Wang, Fangqun

2012-04-01

In this paper, a new high reliability linear drive device, termed as stator-permanent-magnet tubular oscillating actuator (SPM-TOA), is proposed for artificial hearts (AHs). The key is to incorporate the concept of two independent phases into this linear AH device, hence achieving high reliability operation. The fault-tolerant teeth are employed to provide the desired decoupling phases in magnetic circuit. Also, as the magnets and the coils are located in the stator, the proposed SPM-TOA takes the definite advantages of robust mover and direct-drive capability. By using the time-stepping finite element method, the electromagnetic characteristics of the proposed SPM-TOA are analyzed, including magnetic field distributions, flux linkages, back- electromotive forces (back-EMFs) self- and mutual inductances, as well as cogging and thrust forces. The results confirm that the proposed SPM-TOA meets the dimension, weight, and force requirements of the AH drive device.

Scalar Potential Model progress

NASA Astrophysics Data System (ADS)

Hodge, John

2007-04-01

Because observations of galaxies and clusters have been found inconsistent with General Relativity (GR), the focus of effort in developing a Scalar Potential Model (SPM) has been on the examination of galaxies and clusters. The SPM has been found to be consistent with cluster cellular structure, the flow of IGM from spiral galaxies to elliptical galaxies, intergalactic redshift without an expanding universe, discrete redshift, rotation curve (RC) data without dark matter, asymmetric RCs, galaxy central mass, galaxy central velocity dispersion, and the Pioneer Anomaly. In addition, the SPM suggests a model of past expansion, past contraction, and current expansion of the universe. GR corresponds to the SPM in the limit in which a flat and static scalar potential field replaces the Sources and Sinks such as between clusters and on the solar system scale which is small relative to the distance to a Source. The papers may be viewed at http://web.infoave.net/˜scjh/ .

EEG and MEG data analysis in SPM8.

PubMed

Litvak, Vladimir; Mattout, Jérémie; Kiebel, Stefan; Phillips, Christophe; Henson, Richard; Kilner, James; Barnes, Gareth; Oostenveld, Robert; Daunizeau, Jean; Flandin, Guillaume; Penny, Will; Friston, Karl

2011-01-01

SPM is a free and open source software written in MATLAB (The MathWorks, Inc.). In addition to standard M/EEG preprocessing, we presently offer three main analysis tools: (i) statistical analysis of scalp-maps, time-frequency images, and volumetric 3D source reconstruction images based on the general linear model, with correction for multiple comparisons using random field theory; (ii) Bayesian M/EEG source reconstruction, including support for group studies, simultaneous EEG and MEG, and fMRI priors; (iii) dynamic causal modelling (DCM), an approach combining neural modelling with data analysis for which there are several variants dealing with evoked responses, steady state responses (power spectra and cross-spectra), induced responses, and phase coupling. SPM8 is integrated with the FieldTrip toolbox , making it possible for users to combine a variety of standard analysis methods with new schemes implemented in SPM and build custom analysis tools using powerful graphical user interface (GUI) and batching tools.

The Stochastic Parcel Model: A deterministic parameterization of stochastically entraining convection

DOE PAGES

Romps, David M.

2016-03-01

Convective entrainment is a process that is poorly represented in existing convective parameterizations. By many estimates, convective entrainment is the leading source of error in global climate models. As a potential remedy, an Eulerian implementation of the Stochastic Parcel Model (SPM) is presented here as a convective parameterization that treats entrainment in a physically realistic and computationally efficient way. Drawing on evidence that convecting clouds comprise air parcels subject to Poisson-process entrainment events, the SPM calculates the deterministic limit of an infinite number of such parcels. For computational efficiency, the SPM groups parcels at each height by their purity, whichmore » is a measure of their total entrainment up to that height. This reduces the calculation of convective fluxes to a sequence of matrix multiplications. The SPM is implemented in a single-column model and compared with a large-eddy simulation of deep convection.« less

EEG and MEG Data Analysis in SPM8

PubMed Central

Litvak, Vladimir; Mattout, Jérémie; Kiebel, Stefan; Phillips, Christophe; Henson, Richard; Kilner, James; Barnes, Gareth; Oostenveld, Robert; Daunizeau, Jean; Flandin, Guillaume; Penny, Will; Friston, Karl

2011-01-01

SPM is a free and open source software written in MATLAB (The MathWorks, Inc.). In addition to standard M/EEG preprocessing, we presently offer three main analysis tools: (i) statistical analysis of scalp-maps, time-frequency images, and volumetric 3D source reconstruction images based on the general linear model, with correction for multiple comparisons using random field theory; (ii) Bayesian M/EEG source reconstruction, including support for group studies, simultaneous EEG and MEG, and fMRI priors; (iii) dynamic causal modelling (DCM), an approach combining neural modelling with data analysis for which there are several variants dealing with evoked responses, steady state responses (power spectra and cross-spectra), induced responses, and phase coupling. SPM8 is integrated with the FieldTrip toolbox , making it possible for users to combine a variety of standard analysis methods with new schemes implemented in SPM and build custom analysis tools using powerful graphical user interface (GUI) and batching tools. PMID:21437221

Quantitative analysis of the text and graphic content in ophthalmic slide presentations.

PubMed

Ing, Edsel; Celo, Erdit; Ing, Royce; Weisbrod, Lawrence; Ing, Mercedes

2017-04-01

To determine the characteristics of ophthalmic digital slide presentations. Retrospective quantitative analysis. Slide presentations from a 2015 Canadian primary eye care conference were analyzed for their duration, character and word count, font size, words per minute (wpm), lines per slide, words per slide, slides per minute (spm), text density product (wpm × spm), proportion of graphic content, and Flesch Reading Ease (FRE) score using Microsoft PowerPoint and Word. The median audience evaluation score for the lectures was used to dichotomize the higher scoring lectures (HSL) from the lower scoring lectures (LSL). A priori we hypothesized that there would be a difference in the wpm, spm, text density product, and FRE score between HSL and LSL. Wilcoxon rank-sum tests with Bonferroni correction were utilized. The 17 lectures had medians of 2.5 spm, 20.3 words per slide, 5.0 lines per slide, 28-point sans serif font, 36% graphic content, and text density product of 136.4 words × slides/minute 2 . Although not statistically significant, the HSL had more wpm, fewer words per slide, more graphics per slide, greater text density, and higher FRE score than LSL. There was a statistically significant difference in the spm of the HSL (3.1 ± 1.0) versus the LSL (2.2 ± 1.0) at p = 0.0124. All presenters showed more than 1 slide per minute. The HSL showed more spm than the LSL. The descriptive statistics from this study may aid in the preparation of slides used for teaching and conferences. Copyright © 2017 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved.

PAH occurrence in chalk river systems from the Jura region (France). Pertinence of suspended particulate matter and sediment as matrices for river quality monitoring.

PubMed

Chiffre, Axelle; Degiorgi, François; Morin-Crini, Nadia; Bolard, Audrey; Chanez, Etienne; Badot, Pierre-Marie

2015-11-01

This study investigates the variations of polycyclic aromatic hydrocarbon (PAH) levels in surface water, suspended particulate matter (SPM) and sediment upstream and downstream of the discharges of two wastewater treatment plant (WWTP) effluents. Relationships between the levels of PAHs in these different matrices were also investigated. The sum of 16 US EPA PAHs ranged from 73.5 to 728.0 ng L(-1) in surface water and from 85.4 to 313.1 ng L(-1) in effluent. In SPM and sediment, ∑16PAHs ranged from 749.6 to 2,463 μg kg(-1) and from 690.7 μg kg(-1) to 3,625.6 μg kg(-1), respectively. Investigations performed upstream and downstream of both studied WWTPs showed that WWTP discharges may contribute to the overall PAH contaminations in the Loue and the Doubs rivers. Comparison between gammarid populations upstream and downstream of WWTP discharge showed that biota was impacted by the WWTP effluents. When based only on surface water samples, the assessment of freshwater quality did not provide evidence for a marked PAH contamination in either of the rivers studied. However, using SPM and sediment samples, we found PAH contents exceeding sediment quality guidelines. We conclude that sediment and SPM are relevant matrices to assess overall PAH contamination in aquatic ecosystems. Furthermore, we found a positive linear correlation between PAH contents of SPM and sediment, showing that SPM represents an integrating matrix which is able to provide meaningful data about the overall contamination over a given time span.

A multistage crucible of revision and approval shapes IPCC policymaker summaries

PubMed Central

Mach, Katharine J.; Freeman, Patrick T.; Mastrandrea, Michael D.; Field, Christopher B.

2016-01-01

Intergovernmental Panel on Climate Change (IPCC) member governments approve each report’s summary for policymakers (SPM) by consensus, discussing and agreeing on each sentence in a plenary session with scientist authors. A defining feature of IPCC assessment, the governmental approval process builds joint ownership of current knowledge by scientists and governments. The resulting SPM revisions have been extensively discussed in anecdotes, interviews, and perspectives, but they have not been comprehensively analyzed. We provide an in-depth evaluation of IPCC SPM revisions, establishing an evidential basis for understanding their nature. Revisions associated with governmental review and approval generally expand SPMs, with SPM text growing by 17 to 53% across recent assessment reports. Cases of high political sensitivity and failure to reach consensus are notable exceptions, resulting in SPM contractions. In contrast to recent claims, we find that IPCC SPMs are as readable, for multiple metrics of reading ease, as other professionally edited assessment summaries. Across reading-ease metrics, some SPMs become more readable through governmental review and approval, whereas others do not. In an SPM examined through the entire revision process, most revisions associated with governmental review and approval occurred before the start of the government-approval plenary session. These author revisions emphasize clarity, scientific rigor, and explanation. In contrast, the subsequent plenary revisions place greater emphasis especially on policy relevance, comprehensiveness of examples, and nuances of expert judgment. Overall, the value added by the IPCC process emerges in a multistage crucible of revision and approval, as individuals together navigate complex science-policy terrain. PMID:27532046

Regional mapping of soil parent material by machine learning based on point data

NASA Astrophysics Data System (ADS)

Lacoste, Marine; Lemercier, Blandine; Walter, Christian

2011-10-01

A machine learning system (MART) has been used to predict soil parent material (SPM) at the regional scale with a 50-m resolution. The use of point-specific soil observations as training data was tested as a replacement for the soil maps introduced in previous studies, with the aim of generating a more even distribution of training data over the study area and reducing information uncertainty. The 27,020-km 2 study area (Brittany, northwestern France) contains mainly metamorphic, igneous and sedimentary substrates. However, superficial deposits (aeolian loam, colluvial and alluvial deposits) very often represent the actual SPM and are typically under-represented in existing geological maps. In order to calibrate the predictive model, a total of 4920 point soil descriptions were used as training data along with 17 environmental predictors (terrain attributes derived from a 50-m DEM, as well as emissions of K, Th and U obtained by means of airborne gamma-ray spectrometry, geological variables at the 1:250,000 scale and land use maps obtained by remote sensing). Model predictions were then compared: i) during SPM model creation to point data not used in model calibration (internal validation), ii) to the entire point dataset (point validation), and iii) to existing detailed soil maps (external validation). The internal, point and external validation accuracy rates were 56%, 81% and 54%, respectively. Aeolian loam was one of the three most closely predicted substrates. Poor prediction results were associated with uncommon materials and areas with high geological complexity, i.e. areas where existing maps used for external validation were also imprecise. The resultant predictive map turned out to be more accurate than existing geological maps and moreover indicated surface deposits whose spatial coverage is consistent with actual knowledge of the area. This method proves quite useful in predicting SPM within areas where conventional mapping techniques might be too costly or lengthy or where soil maps are insufficient for use as training data. In addition, this method allows producing repeatable and interpretable results, whose accuracy can be assessed objectively.

Sampling of suspended particulate matter using particle traps in the Rhône River: Relevance and representativeness for the monitoring of contaminants.

PubMed

Masson, M; Angot, H; Le Bescond, C; Launay, M; Dabrin, A; Miège, C; Le Coz, J; Coquery, M

2018-05-10

Monitoring hydrophobic contaminants in surface freshwaters requires measuring contaminant concentrations in the particulate fraction (sediment or suspended particulate matter, SPM) of the water column. Particle traps (PTs) have been recently developed to sample SPM as cost-efficient, easy to operate and time-integrative tools. But the representativeness of SPM collected with PTs is not fully understood, notably in terms of grain size distribution and particulate organic carbon (POC) content, which could both skew particulate contaminant concentrations. The aim of this study was to evaluate the representativeness of SPM characteristics (i.e. grain size distribution and POC content) and associated contaminants (i.e. polychlorinated biphenyls, PCBs; mercury, Hg) in samples collected in a large river using PTs for differing hydrological conditions. Samples collected using PTs (n = 74) were compared with samples collected during the same time period by continuous flow centrifugation (CFC). The grain size distribution of PT samples shifted with increasing water discharge: the proportion of very fine silts (2-6 μm) decreased while that of coarse silts (27-74 μm) increased. Regardless of water discharge, POC contents were different likely due to integration by PT of high POC-content phytoplankton blooms or low POC-content flood events. Differences in PCBs and Hg concentrations were usually within the range of analytical uncertainties and could not be related to grain size or POC content shifts. Occasional Hg-enriched inputs may have led to higher Hg concentrations in a few PT samples (n = 4) which highlights the time-integrative capacity of the PTs. The differences of annual Hg and PCB fluxes calculated either from PT samples or CFC samples were generally below 20%. Despite some inherent limitations (e.g. grain size distribution bias), our findings suggest that PT sampling is a valuable technique to assess reliable spatial and temporal trends of particulate contaminants such as PCBs and Hg within a river monitoring network. Copyright © 2018 Elsevier B.V. All rights reserved.

Spontaneous Pneumomediastinum: Case Presentation to a College Student Health Clinic

ERIC Educational Resources Information Center

Spotts, P. Hunter

2017-01-01

The author describes a case of spontaneous pneumomediastinum (SPM) in a 19-year-old man presenting to a college student health clinic. The author also provides a review on SPM, including clinical manifestations, diagnostic evaluation, and management.

Spatial distribution of organic contaminants in three rivers of Southern England bound to suspended particulate material and dissolved in water.

PubMed

Wilkinson, John L; Hooda, Peter S; Swinden, Julian; Barker, James; Barton, Stephen

2017-09-01

The spatial distribution of pharmaceuticals, personal care products (PPCPs) and other emerging contaminants (ECs) such as plasticisers, perflourinated compounds (PFCs) and illicit drug metabolites in water and bound to suspended particulate material (SPM) is not well-understood. Here, we quantify levels of thirteen selected contaminants in water (n=88) and their partition to suspended particulate material (SPM, n=16) in three previously-unstudied rivers of Greater London and Southern England during a key reproduction/spawning period. Analysis was conducted using an in-house validated method for Solid Phase Extraction followed by High-Performance Liquid Chromatography-Tandem Mass-Spectrometry. Analytes were extracted from SPM using an optimised method for ultrasonic-assisted solvent extraction. Detection frequencies of contaminants dissolved in water ranged from 3% (ethinylestradiol) to 100% (bisphenol-A). Overall mean concentrations in the aqueous-phase ranged from 14.7ng/L (benzoylecgonine) to 159ng/L (bisphenol-A). Sewage treatment works (STW) effluent was the predominant source of pharmaceuticals, while plasticisers/perfluorinated compounds may additionally enter rivers via other sources. In SPM, detection frequencies ranged from 44% (PFOA) to 94% (hydroxyacetophenone). Mean quantifiable levels of analytes bound to SPM ranged from 13.5ng/g dry SPM (0.33ng bound/L water) perfluorononanoic acid to 2830ng/g dry SPM (14.3ng bound/L water) perfluorooctanesulfonic acid. Long chain (>C7) amphipathic and acidic PFCs were found to more preferentially bind to SPM than short chain PFCs and other contaminants (Kd=34.1-75.5 vs <5 respectively). Per capita daily contributions of studied contaminants entering rivers ranged from 0.157μg/person/day of benzoylecgonine (cocaine metabolite) to 58.6μg/person/day of bisphenol-A. The large sample size of this work (n=104) enabled ANOVA followed by Tukey HSD post-hoc tests to establish significant trends in PPCP/EC spatial distribution from headwaters through downstream stretches of studied rivers. Novel findings include environmental Kd calculations, the occurrence of contaminants in river headwaters, increases in contaminant metabolite concentrations downstream of STW effluents revealing possible in-river degradation or de-conjugation, the influence of polarity and acidity in the partition of contaminants to particulate-material, among others. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

FDG-PET and CSF biomarker accuracy in prediction of conversion to different dementias in a large multicentre MCI cohort.

PubMed

Caminiti, Silvia Paola; Ballarini, Tommaso; Sala, Arianna; Cerami, Chiara; Presotto, Luca; Santangelo, Roberto; Fallanca, Federico; Vanoli, Emilia Giovanna; Gianolli, Luigi; Iannaccone, Sandro; Magnani, Giuseppe; Perani, Daniela

2018-01-01

In this multicentre study in clinical settings, we assessed the accuracy of optimized procedures for FDG-PET brain metabolism and CSF classifications in predicting or excluding the conversion to Alzheimer's disease (AD) dementia and non-AD dementias. We included 80 MCI subjects with neurological and neuropsychological assessments, FDG-PET scan and CSF measures at entry, all with clinical follow-up. FDG-PET data were analysed with a validated voxel-based SPM method. Resulting single-subject SPM maps were classified by five imaging experts according to the disease-specific patterns, as "typical-AD", "atypical-AD" (i.e. posterior cortical atrophy, asymmetric logopenic AD variant, frontal-AD variant), "non-AD" (i.e. behavioural variant FTD, corticobasal degeneration, semantic variant FTD; dementia with Lewy bodies) or "negative" patterns. To perform the statistical analyses, the individual patterns were grouped either as "AD dementia vs. non-AD dementia (all diseases)" or as "FTD vs. non-FTD (all diseases)". Aβ42, total and phosphorylated Tau CSF-levels were classified dichotomously, and using the Erlangen Score algorithm. Multivariate logistic models tested the prognostic accuracy of FDG-PET-SPM and CSF dichotomous classifications. Accuracy of Erlangen score and Erlangen Score aided by FDG-PET SPM classification was evaluated. The multivariate logistic model identified FDG-PET "AD" SPM classification (Expβ = 19.35, 95% C.I. 4.8-77.8, p < 0.001) and CSF Aβ42 (Expβ = 6.5, 95% C.I. 1.64-25.43, p < 0.05) as the best predictors of conversion from MCI to AD dementia. The "FTD" SPM pattern significantly predicted conversion to FTD dementias at follow-up (Expβ = 14, 95% C.I. 3.1-63, p < 0.001). Overall, FDG-PET-SPM classification was the most accurate biomarker, able to correctly differentiate either the MCI subjects who converted to AD or FTD dementias, and those who remained stable or reverted to normal cognition (Expβ = 17.9, 95% C.I. 4.55-70.46, p < 0.001). Our results support the relevant role of FDG-PET-SPM classification in predicting progression to different dementia conditions in prodromal MCI phase, and in the exclusion of progression, outperforming CSF biomarkers.

Theory of CW lidar aerosol backscatter measurements and development of a 2.1 microns solid-state pulsed laser radar for aerosol backscatter profiling

NASA Technical Reports Server (NTRS)

Kavaya, Michael J.; Henderson, Sammy W.; Frehlich, R. G.

1991-01-01

The performance and calibration of a focused, continuous wave, coherent detection CO2 lidar operated for the measurement of atmospheric backscatter coefficient, B(m), was examined. This instrument functions by transmitting infrared (10 micron) light into the atmosphere and collecting the light which is scattered in the rearward direction. Two distinct modes of operation were considered. In volume mode, the scattered light energy from many aerosols is detected simultaneously, whereas in the single particle mode (SPM), the scattered light energy from a single aerosol is detected. The analysis considered possible sources of error for each of these two cases, and also considered the conditions where each technique would have superior performance. The analysis showed that, within reasonable assumptions, the value of B(m) could be accurately measured by either the VM or the SPM method. The understanding of the theory developed during the analysis was also applied to a pulsed CO2 lidar. Preliminary results of field testing of a solid state 2 micron lidar using a CW oscillator is included.

Anomalous reduction in the long-time flux creep relaxation in superconducting Ca10(Pt4As8)((Fe1‑x Pt x )2As2)5 (x ≈ 0.05) single crystals

NASA Astrophysics Data System (ADS)

Haberkorn, N.; Huang, Silu; Jin, R.

2018-06-01

We report the vortex dynamics of superconducting a Ca10(Pt4As8)((Fe1‑x Pt x )2As2)5 (x ≈ 0.05) single crystal with T c = 26 K investigated by performing magnetic measurements. The field dependence of the magnetization displays a second peak (SPM), typically related to a crossover between elastic and plastic vortex relaxation in a weak pinning scenario. Long-time flux creep relaxation measurements for fields smaller that of the SPM show that the vortex dynamics can be separated in two different regions. For magnetic fields smaller than the lower end of the SPM, glassy relaxation (with a characteristic glassy exponent μ) is observed. For magnetic fields between the lower end and the SPM, the flux creep rate decreases systematically to values below to the ones predicted by the collective theory. This effect can be understood by considering a stable vortex lattice configuration. As the field position of the SPM can be adjusted by modifying the quenched potential, our results suggest that extremely low flux creep relaxation rate may be tuned in many other superconducting materials.

Analytical Characterization of SPM Impact on XPM-Induced Degradation in Dispersion-Compensated WDM Systems

NASA Astrophysics Data System (ADS)

Luís, Ruben S.; Cartaxo, Adolfo V. T.

2005-03-01

This paper proposes the definition of a cross-phase modulation (XPM)-induced power penalty for intensity modulation/direct detection (IM-DD) systems as a function of the normalized variance of the XPM-induced IM. This allows the definition of 1-dB power penalty reference values. New expressions of the equivalent linear model transfer functions for the XPM-induced IM and phase modulation (PM) that include the influence of self-phase modulation (SPM) as well as group-velocity dispersion are derived. The new expressions allow a significant extension for higher powers and dispersion parameters of expressions derived in previous papers for single-segment and multisegment fiber systems with dispersion compensation. Good agreement between analytical results and numerical simulations is obtained. Consistency with work performed numerically and experimentally by other authors is shown, validating the proposed model. Using the proposed model, the influence of residual dispersion and SPM on the limitations imposed by XPM on the performance of dispersion-compensated systems is assessed. It is shown that inline residual dispersion may lead to performance improvement for a properly tuned total residual dispersion. The influence of SPM is shown to degrade the system performance when nonzero-dispersion-shifted fiber is used. However, systems using standard single-mode fiber may benefit from the presence of SPM.

Suspended particulate matter collection methods influence the quantification of polycyclic aromatic compounds in the river system.

PubMed

Abuhelou, Fayez; Mansuy-Huault, Laurence; Lorgeoux, Catherine; Catteloin, Delphine; Collin, Valéry; Bauer, Allan; Kanbar, Hussein Jaafar; Gley, Renaud; Manceau, Luc; Thomas, Fabien; Montargès-Pelletier, Emmanuelle

2017-10-01

In this study, we compared the influence of two different collection methods, filtration (FT) and continuous flow field centrifugation (CFC), on the concentration and the distribution of polycyclic aromatic compounds (PACs) in suspended particulate matter (SPM) occurring in river waters. SPM samples were collected simultaneously with FT and CFC from a river during six sampling campaigns over 2 years, covering different hydrological contexts. SPM samples were analyzed to determine the concentration of PACs including 16 polycyclic aromatic hydrocarbons (PAHs), 11 oxygenated PACs (O-PACs), and 5 nitrogen PACs (N-PACs). Results showed significant differences between the two separation methods. In half of the sampling campaigns, PAC concentrations differed from a factor 2 to 30 comparing FT and CFC-collected SPMs. The PAC distributions were also affected by the separation method. FT-collected SPM were enriched in 2-3 ring PACs whereas CFC-collected SPM had PAC distributions dominated by medium to high molecular weight compounds typical of combustion processes. This could be explained by distinct cut-off threshold of the two separation methods and strongly suggested the retention of colloidal and/or fine matter on glass-fiber filters particularly enriched in low molecular PACs. These differences between FT and CFC were not systematic but rather enhanced by high water flow rates.

Development of an indirect ELISA based on the recombinant Spm2 protein for detection of tropical theileriosis.

PubMed

Tian, Zhancheng; Du, Xiaoyue; Du, Junzheng; Gao, Shandian; Yu, Ruiming; Hassan, Muhammad Adeel; Liu, Guangyuan; Luo, Jianxun; Yin, Hong

2018-06-01

Tropical theileriosis, caused by Theileria annulata, is distributed worldwide and causes great economic losses in dairy. The reliable diagnostic method is critical for prevention and control of the disease. In this study, a sporozoite and macroschizont gene 2 (spm2) protein from T. annulata was used to develop an indirect ELISA for tropical theileriosis. Specificity test showed that there were no cross-reactions with antibodies raised against other bovine piroplasm species using ELISA or western blotting. The specificity and sensitivity were 98.4% and 98.7%, respectively, with a threshold of 35.5% of the specific mean antibody rate (AbR). Furthermore, a total of 196 field sera samples collected from Xinjiang and Gansu provinces were detected by the spm2 ELISA and IFA. The results obtained with the spm2 ELISA and IFA in this study had the moderate agreement. The average positive rates of T. annulata sera samples detected in the present study were close to the prevalence of previous reports in these endemic areas. This indicated that the Spm2 ELISA could be used as a reliable diagnostic tool for serological survey of T. annulata infection in areas where Theileria parva is not present. Copyright © 2018 Elsevier B.V. All rights reserved.

Bitopic Sphingosine 1-Phosphate Receptor 3 (S1P3) Antagonist Rescue from Complete Heart Block: Pharmacological and Genetic Evidence for Direct S1P3 Regulation of Mouse Cardiac Conduction.

PubMed

Sanna, M Germana; Vincent, Kevin P; Repetto, Emanuela; Nguyen, Nhan; Brown, Steven J; Abgaryan, Lusine; Riley, Sean W; Leaf, Nora B; Cahalan, Stuart M; Kiosses, William B; Kohno, Yasushi; Brown, Joan Heller; McCulloch, Andrew D; Rosen, Hugh; Gonzalez-Cabrera, Pedro J

2016-01-01

The molecular pharmacology of the G protein-coupled receptors for sphingosine 1-phosphate (S1P) provides important insight into established and new therapeutic targets. A new, potent bitopic S1P3 antagonist, SPM-354, with in vivo activity, has been used, together with S1P3-knockin and S1P3-knockout mice to define the spatial and functional properties of S1P3 in regulating cardiac conduction. We show that S1P3 is a key direct regulator of cardiac rhythm both in vivo and in isolated perfused hearts. 2-Amino-2-[2-(4-octylphenyl)ethyl]propane-1,3-diol in vivo and S1P in isolated hearts induced a spectrum of cardiac effects, ranging from sinus bradycardia to complete heart block, as measured by a surface electrocardiogram in anesthetized mice and in volume-conducted Langendorff preparations. The agonist effects on complete heart block are absent in S1P3-knockout mice and are reversed in wild-type mice with SPM-354, as characterized and described here. Homologous knockin of S1P3-mCherry is fully functional pharmacologically and is strongly expressed by immunohistochemistry confocal microscopy in Hyperpolarization Activated Cyclic Nucleotide Gated Potassium Channel 4 (HCN4)-positive atrioventricular node and His-Purkinje fibers, with relative less expression in the HCN4-positive sinoatrial node. In Langendorff studies, at constant pressure, SPM-354 restored sinus rhythm in S1P-induced complete heart block and fully reversed S1P-mediated bradycardia. S1P3 distribution and function in the mouse ventricular cardiac conduction system suggest a direct mechanism for heart block risk that should be further studied in humans. A richer understanding of receptor and ligand usage in the pacemaker cells of the cardiac system is likely to be useful in understanding ventricular conduction in health, disease, and pharmacology. Copyright © 2015 by The American Society for Pharmacology and Experimental Therapeutics.

Synthesis, characterization and magnetic properties of CoxCu1-x (x ∼ 0.01 - 0.3) granular alloys

NASA Astrophysics Data System (ADS)

Dhara, S.; Roy Chowdhury, R.; Lahiri, S.; Ray, P.; Bandyopadhyay, B.

2015-01-01

Nanostructured CoCu granular alloys have been prepared by borohydride reduction of CuCl2 and CoCl2 salt solutions using cetyltrimethylammonium bromide (CTAB) as a surfactant. Characterization by inductively coupled plasma optical emission spectroscopy (ICPOES), X-ray diffraction (XRD) and transmission electron microscopy (TEM) studies yields spherical particles of CoxCu1-x (x ∼ 0.01 - 0.3) of average size 8-25 nm formed in a face-centered-cubic (fcc) lattice as in copper. Studies of zero-field-cooled/field-cooled (ZFC/FC) magnetization and thermoremanent magnetization (TRM) have been performed in the temperature range 4-300 K, and the results have been analyzed by independent particle model. At the lowest cobalt concentration (x ∼ 0.01), the alloy is superparamagnetic and there is no blocking of magnetization down to 4 K. For all other samples, the magnetization at low magnetic field is characterized by a blocking temperature distribution which is not influenced by the Co content in samples. Study of hysteresis loops shows that the magnetization at any temperature 4-300 K is a sum of ferromagnetic (FM), superparamagnetic (SPM) and paramagnetic (PM) contributions. The FM part increases and SPM part decreases with increase in Co content. However, the values of coercivity and magnetic anisotropy constant do not depend on Co content. The results suggest that CoxCu1-x alloys are formed in a spherical core-shell type structure with cobalt being concentrated near the core of particles.

Interferometer-Controlled Optical Tweezers Constructed for Nanotechnology and Biotechnology

NASA Technical Reports Server (NTRS)

Decker, Arthur J.

2002-01-01

A new method to control microparticles was developed in-house at the NASA Glenn Research Center in support of the nanotechnology project under NASA's Aerospace Propulsion and Power Base Research Program. A prototype interferometer-controlled optical tweezers was constructed to manipulate scanning probe microscope (SPM) tips. A laser beam passed through a Mach-Zehnder interferometer, and a microscope objective then produced an optical trap from the coaxial beams. The trap levitated and generated the coarse motion of a 10-mm polystyrene sphere used to simulate a SPM tip. The interference between the beams provided fine control of the forces and moments on the sphere. The interferometer included a piezoelectric-scanned mirror to modulate the interference pattern. The 10-mm sphere was observed to oscillate about 1 mm as the mirror and fringe pattern oscillated. The prototype tweezers proved the feasibility of constructing a more sophisticated interferometer tweezers to hold and manipulate SPM tips. The SPM tips are intended to interrogate and manipulate nanostructures. A more powerful laser will be used to generate multiple traps to hold nanostructures and SPM tips. The vibrating mirror in the interferometer will be replaced with a spatial light modulator. The modulator will allow the optical phase distribution in one leg of the interferometer to be programmed independently at 640 by 480 points for detailed control of the forces and moments. The interference patterns will be monitored to measure the motion of the SPM tips. Neuralnetwork technology will provide fast analysis of the interference patterns for diagnostic purposes and for local or remote feedback control of the tips. This effort also requires theoretical and modeling support in the form of scattering calculations for twin coherent beams from nonspherical particles.

Synthesis and evaluation of the antioxidative potential of minoxidil-polyamine conjugates.

PubMed

Hadjipavlou-Litina, Dimitra; Magoulas, George E; Bariamis, Stavros E; Tsimali, Zinovia; Avgoustakis, Konstantinos; Kontogiorgis, Christos A; Athanassopoulos, Constantinos M; Papaioannou, Dionissios

2013-07-01

A series of conjugates (MNX-CO-PA) of minoxidil (MNX) with the polyamines (PAs) putrescine (PUT), spermidine (SPD) and spermine (SPM) as well as dopamine were produced through activation of MNX with N,N'-carbonyldiimidazole, followed by reaction with dopamine or selectively protected PAs and acid-mediated deprotection. These conjugates together with conjugates of the general type MNX-PA or PA-MNX-PA, readily produced using literature protocols, were tested as antioxidants. The most potent inhibitors of lipid peroxidation were the conjugates MNX-SPM (2, 94%), SPM-MNX-SPM (4, 94%) and MNX-N(4)-SPD (7, 91%) and MNX (91%). The most powerful lipoxygenase (LOX) inhibitors were MNX (IC50 = 20 μM) and the conjugates MNX-N(8)-SPD (9, IC50 = 22.1 μM), MNX-CO-dopamine (11, IC50 = 28 μM) and MNX-N(1)-SPD (8, IC50 = 30 μM). The most interesting conjugates 2, MNX-CO-PUT (5), 8 and 11 as well as MNX were generally found to exhibit weaker (22-36.5%) or no (conjugate 8) anti-inflammatory activity than indomethacin (47%) with the exception of MNX which showed almost equal potency (49%) to indomethacin. The cytocompatibility of conjugates and MNX at the highest concentration of 100 μM showed a survival percentage of 87-107%, with the exception of conjugates with SPM (compound 2) and MNX-CO-SPM (6), which showed considerable cytotoxicity (survival percentage 8-14%). Molecular docking studies were carried on conjugate 9 and the parent compound MNX and were found to be in accordance with our experimental biological results. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Colon targeted delivery systems of metronidazole based on osmotic technology: development and evaluation.

PubMed

Kumar, Pramod; Singh, Sanjay; Mishra, Brahmeshwar

2008-09-01

Colon targeted delivery systems of metronidazole (MTZ) based on osmotic technology were developed. The developed systems consisted of osmotic core (drug, osmotic agent and wicking agent), coated with semipermeable membrane (SPM) containing guar gum as pore former, coated core were then further coated with enteric coating to protect the system from acidic environment of stomach. The effect of various formulation variables namely the level of wicking agent (sodium lauryl sulphate), osmotic agent in the osmotic core, the level of pore former (guar gum) in SPM, and the thickness of SPM, were studied on physical parameters and drug release characteristics of developed formulations. MTZ release was inversely proportional to SPM thickness, but directly related to the level of pore former, wicking agent and osmotic agent. On the other hand burst strength of the exhausted shells was decreased with the increase in level of pore former in the membrane but increased with the increase in the thickness of SPM. The drug release from the developed formulations was independent of pH, and agitation intensity, but dependent on the osmotic pressure of the release media. The thickness of enteric coating could prevent formation of delivery pores before contact with simulated colonic fluid, but had no effect on drug release. Result of SEM studies showed the formation of in-situ delivery pores in the membrane from where the drug release occurred, and the number of pores formed were directly related to the initial level of pore former (guar gum) in SPM. The manufacturing procedure was found to be reproducible and formulations were found to be stable during 3 months of accelerated stability studies.

Theory of Self-Phase Modulation and Spectral Broadening

NASA Astrophysics Data System (ADS)

Shen, Y. R.; Yang, Guo-Zhen

Self-phase modulation refers to the phenomenon in which a laser beam propagating in a medium interacts with the medium and imposes a phase modulation on itself. It is one of those very fascinating effects discovered in the early days of nonlinear optics (Bloembergen and Lallemand, 1966; Brewer, 1967; Cheung et al., 1968; Lallemand, 1966; Jones and Stoicheff, 1964; Shimizu, 1967; Stoicheff, 1963). The physical origin of the phenomenon lies in the fact that the strong field of a laser beam is capable of inducing an appreciable intensity-dependent refractive index change in the medium. The medium then reacts back and inflicts a phase change on the incoming wave, resulting in self-phase modulation (SPM). Since a laser beam has a finite cross section, and hence a transverse intensity profile, SPM on the beam should have a transverse spatial dependence, equivalent to a distortion of the wave front. Consequently, the beam will appear to have self-diffracted. Such a self-diffraction action, resulting from SPM in space, is responsible for the well-known nonlinear optical phenomena of self-focusing and self-defocusing (Marburger, 1975; Shen, 1975). It can give rise to a multiple ring structure in the diffracted beam if the SPM is sufficiently strong (Durbin et al., 1981; Santamato and Shen, 1984). In the case of a pulsed laser input, the temporal variation of the laser intensity leads to an SPM in time. Since the time derivative of the phase of a wave is simply the angular frequency of the wave, SPM also appears as a frequency modulation. Thus, the output beam appears with a self-induced spectral broadening (Cheung et al., 1968; Gustafson et al., 1969; Shimizu, 1967).

The impact of missing sensor information on surgical workflow management.

PubMed

Liebmann, Philipp; Meixensberger, Jürgen; Wiedemann, Peter; Neumuth, Thomas

2013-09-01

Sensor systems in the operating room may encounter intermittent data losses that reduce the performance of surgical workflow management systems (SWFMS). Sensor data loss could impact SWFMS-based decision support, device parameterization, and information presentation. The purpose of this study was to understand the robustness of surgical process models when sensor information is partially missing. SWFMS changes caused by wrong or no data from the sensor system which tracks the progress of a surgical intervention were tested. The individual surgical process models (iSPMs) from 100 different cataract procedures of 3 ophthalmologic surgeons were used to select a randomized subset and create a generalized surgical process model (gSPM). A disjoint subset was selected from the iSPMs and used to simulate the surgical process against the gSPM. The loss of sensor data was simulated by removing some information from one task in the iSPM. The effect of missing sensor data was measured using several metrics: (a) successful relocation of the path in the gSPM, (b) the number of steps to find the converging point, and (c) the perspective with the highest occurrence of unsuccessful path findings. A gSPM built using 30% of the iSPMs successfully found the correct path in 90% of the cases. The most critical sensor data were the information regarding the instrument used by the surgeon. We found that use of a gSPM to provide input data for a SWFMS is robust and can be accurate despite missing sensor data. A surgical workflow management system can provide the surgeon with workflow guidance in the OR for most cases. Sensor systems for surgical process tracking can be evaluated based on the stability and accuracy of functional and spatial operative results.

Spatial variation and sources of polycyclic aromatic hydrocarbons influenced by intensive land use in an urbanized river network of East China.

PubMed

Bi, Chunjuan; Wang, Xueping; Jia, Jinpu; Chen, Zhenlou

2018-06-15

The concentrations and distribution of polycyclic aromatic hydrocarbons (PAHs) in urbanized river networks are strongly influenced by intensive land use, industrial activities and population density. The spatial variations and their influencing factors of 16 priority PAHs were investigated in surface water, suspended particulate matter (SPM) and sediments among areas under different intensive land uses (industrial areas, agricultural areas, inner city, suburban towns and island areas) in the Shanghai river network, East China. Source apportionment was carried out using isomer ratios of PAHs and Positive Matrix Factorization (PMF). Total concentrations of 16 PAHs ranged from 105.2 to 400.5 ng/L, 108.1 to 1058.8 ng/L and 104.4 to 19,480.0 ng/g in water, SPM and sediments, respectively. The concentrations of PAHs in SPM and sediments varied significantly among areas (p < 0.05), with the highest concentrations in inner city characterized by highly intensive land use and high population density. The PAH concentrations in sediments were positively correlated with those in SPM and were more strongly correlated with black carbon than with total organic carbon, indicating a stronger influence of prolonged anthropogenic contamination than the recent surface input in sediments. Biomass and coal combustion contributed strongly to total PAHs, followed by natural gas combustion in water and SPM, and vehicular emissions in sediments. Vehicular emissions were the strongest contributors in SPM and sediments of the inner city, indicating the strong influence of vehicular transportation to PAHs pollution in the urbanized river network. Copyright © 2018 Elsevier B.V. All rights reserved.

The impact of disposal of fine-grained sediments from maintenance dredging works on SPM concentration and fluid mud in and outside the harbor of Zeebrugge

NASA Astrophysics Data System (ADS)

Fettweis, Michael; Baeye, Matthias; Cardoso, Claudio; Dujardin, Arvid; Lauwaert, Brigitte; Van den Eynde, Dries; Van Hoestenberghe, Thomas; Vanlede, Joris; Van Poucke, Luc; Velez, Carlos; Martens, Chantal

2016-11-01

The amount of sediments to be dredged and disposed depends to a large part on the suspended particulate matter (SPM) concentration. Tidal, meteorological, climatological, and seasonal forcings have an influence on the horizontal and vertical distribution of the SPM in the water column and on the bed and control the inflow of fine-grained sediments towards harbors and navigation channels. About 3 million tons (dry matter) per year of mainly fine-grained sediments is dredged in the port of Zeebrugge and is disposed on a nearby disposal site. The disposed sediments are quickly resuspended and transported away from the site. The hypothesis is that a significant part of the disposed sediments recirculates back to the dredging places and that a relocation of the disposal site to another location at equal distance to the dredging area would reduce this recirculation. In order to validate the hypothesis, a 1-year field study was set up in 2013-2014. During 1 month, the dredged material was disposed at a new site. Variations in SPM concentration were related to tides, storms, seasonal changes, and human impacts. In the high-turbidity Belgian near-shore area, the natural forcings are responsible for the major variability in the SPM concentration signal, while disposal has only a smaller influence. The conclusion from the measurements is that the SPM concentration decreases after relocation of the disposal site but indicate stronger (first half of field experiment) or weaker (second half of field experiment) effects that are, however, supported by the environmental conditions. The results of the field study may have consequences on the management of disposal operations as the effectiveness of the disposal site depends on environmental conditions, which are inherently associated with chaotic behavior.

Cross-Phase Modulation: A New Technique for Controlling the Spectral, Temporal, and Spatial Properties of Ultrashort Pulses

NASA Astrophysics Data System (ADS)

Baldeck, P. L.; Ho, P. P.; Alfano, Robert R.

Self-phase modulation (SPM) is the principal mechanism responsible for the generation of picosecond and femtosecond white-light supercontinua. When an intense ultrashort pulse progagates through a medium, it distorts the atomic configuration of the material, which changes the refractive index. The pulse phase is time modulated, which causes the generation of new frequencies. This phase modulation originates from the pulse itself (self-phase modulation). It can also be generated by a copropagating pulse (cross-phase modulation).

High-power picosecond pulses by SPM-induced spectral compression in a fiber amplifier

NASA Astrophysics Data System (ADS)

Schreiber, T.; Liem, A.; Roeser, F.; Zellmer, H.; Tuennermann, A.; Limpert, J.; Deguil-Robin, N.; Manek-Honninger, I.; Salin, F.; Courjaud, A.; Honninger, C.; Mottay, E.

2005-04-01

The fiber based generation of nearly transform-limited 10-ps pulses with 200 kW peak power (97 W average power) based on SPM-induced spectral compression is reported. Efficient second harmonic generation applying this source is also discussed.

Innovative SPM Probes for Energy-Storage Science: MWCNT-Nanopipettes to Nanobattery Probes

NASA Astrophysics Data System (ADS)

Larson, Jonathan; Talin, Alec; Pearse, Alexander; Kozen, Alexander; Reutt-Robey, Janice

As energy-storage materials and designs continue to advance, new tools are needed to direct and explore ion insertion/de-insertion at well-defined battery materials interfaces. Scanned probe tips, assembled from actual energy-storage materials, permit SPM measures of local cathode-anode (tip-sample) interactions, including ion transfer. We present examples of ``cathode'' MWCNT-terminated STM probe tips interacting with Li(s)/Si(111) anode substrates. The MWCNT tip functions as both SPM probe and Li-nanopipette,[1] for controlled transport and manipulation of Li. Local field conditions for lithium ionization and transfer are determined and compared to electrostatic models. Additional lithium metallic and oxide tips have been prepared by thin film deposition on conventional W tips, the latter of which effectively functions as a nanobattery. We demonstrate use of these novel probe materials in the local lithiation of low-index Si anode interfaces, probing local barriers for lithium insertion. Prospects and limitations of these novel SPM probes will be discussed. U.S. Department of Energy Award Number DESC0001160.

A robust sebum, oil, and particulate pollution model for assessing cleansing efficacy of human skin.

PubMed

Peterson, G; Rapaka, S; Koski, N; Kearney, M; Ortblad, K; Tadlock, L

2017-06-01

With increasing concerns over the rise of atmospheric particulate pollution globally and its impact on systemic health and skin ageing, we have developed a pollution model to mimic particulate matter trapped in sebum and oils creating a robust (difficult to remove) surrogate for dirty, polluted skin. To evaluate the cleansing efficacy/protective effect of a sonic brush vs. manual cleansing against particulate pollution (trapped in grease/oil typical of human sebum). The pollution model (Sebollution; sebum pollution model; SPM) consists of atmospheric particulate matter/pollution combined with grease/oils typical of human sebum. Twenty subjects between the ages of 18-65 were enrolled in a single-centre, cleansing study comparisons between the sonic cleansing brush (normal speed) compared to manual cleansing. Equal amount of SPM was applied to the centre of each cheek (left and right). Method of cleansing (sonic vs. manual) was randomized to the side of the face (left or right) for each subject. Each side was cleansed for five-seconds using the sonic cleansing device with sensitive brush head or manually, using equal amounts of water and a gel cleanser. Photographs (VISIA-CR, Canfield Imaging, NJ, USA) were taken at baseline (before application of the SPM), after application of SPM (pre-cleansing), and following cleansing. Image analysis (ImageJ, NIH, Bethesda, MD, USA) was used to quantify colour intensity (amount of particulate pollutants on the skin) using a scale of 0 to 255 (0 = all black pixels; 255 = all white pixels). Differences between the baseline and post-cleansing values (pixels) are reported as the amount of SPM remaining following each method of cleansing. Using a robust cleansing protocol to assess removal of pollutants (SPM; atmospheric particulate matter trapped in grease/oil), the sonic brush removed significantly more SPM than manual cleansing (P < 0.001). While extreme in colour, this pollution method easily allows assessment of efficacy through image analysis. © 2016 The Authors. International Journal of Cosmetic Science published by John Wiley & Sons Ltd on behalf of Society of Cosmetic Scientists and the Société Française de Cosmétologie.

The tetravalent organic cation spermine causes the gating of the IRK1 channel expressed in murine fibroblast cells.

PubMed Central

Ishihara, K; Hiraoka, M; Ochi, R

1996-01-01

1. The activation kinetics of the IRK1 channel stably expressed in L cells (a murine fibroblast cell line) were studied under the whole-cell voltage clamp. Without polyamines or Mg2+ in the pipettes, inward currents showed an exponential activation on hyperpolarization. The steep inward rectification of the currents around the reversal potential (Erev) could be described by the open-close transition of the channel with first-order kinetics. 2. When the tetravalent organic cation spermine (Spm) was added in the pipettes, the activation kinetics changed; this was explicable by the increase in the closing rate constant. The activation of the currents observed without Spm or Mg2+ in the pipettes was ascribed to the unblocking of the 'endogenous-Spm block'. 3. In the presence of the divalent cation putrescine (Put) or of Mg2+ in the pipettes, a different non-conductive state suppressed the outward currents on depolarization; the channels instantaneously changed to the open state on repolarization. As the depolarization was prolonged, this non-conductive state was replaced by the non-conductive state that shows an exponential activation on repolarization. This phenomenon was attributed to the redistribution of the channels from the Put- or Mg(2+)-blocked state to the 'endogenous Spm-blocked state' during depolarization. 4. In the presence of the trivalent cation spermidine (Spd) in the pipettes, two different non-conductive states occurred, showing a faster and a slower activation on repolarization. The rectification around Erev was mainly due to the non-conductive state showing a faster activation, which appeared to be the Spd-blocked state. During depolarization, redistribution of the channels to the 'endogenous Spm-blocked state' also occurred. 5. In the presence of Spd, Put or Mg2+ in the pipettes, the voltage dependence of the activation time constant reflecting the unblocking of the 'endogenous Spm' was shifted in the hyperpolarizing direction. 6. Our results suggest that the 'intrinsic gating' that shows the time-dependent activation on repolarization, and that is responsible for the inward rectification around Erev, reflects the blocking kinetics of the tetravalent Spm. PMID:8866861

Particulate matter modifies the association between airborne pollen and daily medical consultations for pollinosis in Tokyo.

PubMed

Konishi, Shoko; Ng, Chris Fook Sheng; Stickley, Andrew; Nishihata, Shinichi; Shinsugi, Chisa; Ueda, Kayo; Takami, Akinori; Watanabe, Chiho

2014-11-15

Pollen from Japanese cedar (sugi) and cypress (hinoki) trees is responsible for the growing prevalence of allergic rhinitis, especially pollinosis in Japan. Previous studies have suggested that air pollutants enhance the allergic response to pollen in susceptible individuals. We conducted a time-stratified case-crossover study to examine the potential modifying effects of PM2.5 and suspended particulate matter (SPM) on the association between pollen concentration and daily consultations for pollinosis. A total of 11,713 daily pollinosis cases (International Classification of Diseases, ICD-10, J30.1) from January to May, 2001-2011, were obtained from a clinic in Chiyoda, Tokyo. Daily pollen counts and the daily mean values of air pollutants (PM2.5, SPM, SO2, NO2, CO, and O3) were collected from monitoring stations across Tokyo. The effects of pollen were stratified by the level of PM2.5 and SPM to examine the interaction effect of pollen and particulate pollutants. We found a statistically significant interaction between pollen concentration and PM2.5/SPM. On days with a high level of PM2.5 (>95th percentile), an interquartile increase in the mean cumulative pollen count (an average of 28 pollen grains per cm(2) during lag-days 0 to 5) corresponded to a 10.30% (95%CI: 8.48%-12.16%) increase in daily new pollinosis cases, compared to 8.04% (95%CI: 7.28%-8.81%) on days with a moderate level of PM2.5 (5th-95th percentile). This interaction persisted when different percentile cut-offs were used and was robust to the inclusion of other air pollutants. A similar interaction pattern was observed between SPM and pollen when a less extreme cut-off for SPM was used to stratify the effect of pollen. Our study showed the acute effect of pollen was greater when the concentration of air particulate pollutant, specifically PM2.5 and SPM, was higher. These findings are consistent with the notion that particulate air pollution may act as an adjuvant that promotes allergic disease (i.e. pollinosis). Copyright © 2014 Elsevier B.V. All rights reserved.

Construction and comparative evaluation of different activity detection methods in brain FDG-PET.

PubMed

Buchholz, Hans-Georg; Wenzel, Fabian; Gartenschläger, Martin; Thiele, Frank; Young, Stewart; Reuss, Stefan; Schreckenberger, Mathias

2015-08-18

We constructed and evaluated reference brain FDG-PET databases for usage by three software programs (Computer-aided diagnosis for dementia (CAD4D), Statistical Parametric Mapping (SPM) and NEUROSTAT), which allow a user-independent detection of dementia-related hypometabolism in patients' brain FDG-PET. Thirty-seven healthy volunteers were scanned in order to construct brain FDG reference databases, which reflect the normal, age-dependent glucose consumption in human brain, using either software. Databases were compared to each other to assess the impact of different stereotactic normalization algorithms used by either software package. In addition, performance of the new reference databases in the detection of altered glucose consumption in the brains of patients was evaluated by calculating statistical maps of regional hypometabolism in FDG-PET of 20 patients with confirmed Alzheimer's dementia (AD) and of 10 non-AD patients. Extent (hypometabolic volume referred to as cluster size) and magnitude (peak z-score) of detected hypometabolism was statistically analyzed. Differences between the reference databases built by CAD4D, SPM or NEUROSTAT were observed. Due to the different normalization methods, altered spatial FDG patterns were found. When analyzing patient data with the reference databases created using CAD4D, SPM or NEUROSTAT, similar characteristic clusters of hypometabolism in the same brain regions were found in the AD group with either software. However, larger z-scores were observed with CAD4D and NEUROSTAT than those reported by SPM. Better concordance with CAD4D and NEUROSTAT was achieved using the spatially normalized images of SPM and an independent z-score calculation. The three software packages identified the peak z-scores in the same brain region in 11 of 20 AD cases, and there was concordance between CAD4D and SPM in 16 AD subjects. The clinical evaluation of brain FDG-PET of 20 AD patients with either CAD4D-, SPM- or NEUROSTAT-generated databases from an identical reference dataset showed similar patterns of hypometabolism in the brain regions known to be involved in AD. The extent of hypometabolism and peak z-score appeared to be influenced by the calculation method used in each software package rather than by different spatial normalization parameters.

Fully automated processing of fMRI data in SPM: from MRI scanner to PACS.

PubMed

Maldjian, Joseph A; Baer, Aaron H; Kraft, Robert A; Laurienti, Paul J; Burdette, Jonathan H

2009-01-01

Here we describe the Wake Forest University Pipeline, a fully automated method for the processing of fMRI data using SPM. The method includes fully automated data transfer and archiving from the point of acquisition, real-time batch script generation, distributed grid processing, interface to SPM in MATLAB, error recovery and data provenance, DICOM conversion and PACS insertion. It has been used for automated processing of fMRI experiments, as well as for the clinical implementation of fMRI and spin-tag perfusion imaging. The pipeline requires no manual intervention, and can be extended to any studies requiring offline processing.

Design research of nanopositioner based on SPM and its simulation of FEM

NASA Astrophysics Data System (ADS)

Zhang, Zhenyu; Li, Hongqi; Zhou, Hongxiu; Li, Linan; Liu, Xiangjun

2006-01-01

A novel nanopositioning stage was designed according to the scanning property of SPM with flexure hinge as kinematic structure and piezoelectric ceramic as actuator. Kinetic precision and X directional area of nanopositioner are 1.55nm and 26.4 micron, respectively, which is demonstrated by kinetic analysis and finite element method FEM simulation. Designed nanopositioner based on SPM moves at 3 dimensions with nanometer scale and its motion of X, Y, and Z directions is decoupled and isotropic. Furthermore, frame of nanopositioner is simple and manufacturing is convenient, which will have broad prospect in the field of nanopositioning and nanotracing.

The application of statistical parametric mapping to 123I-FP-CIT SPECT in dementia with Lewy bodies, Alzheimer's disease and Parkinson's disease.

PubMed

Colloby, Sean J; O'Brien, John T; Fenwick, John D; Firbank, Michael J; Burn, David J; McKeith, Ian G; Williams, E David

2004-11-01

Dopaminergic loss can be visualised using (123)I-FP-CIT single photon emission computed tomography (SPECT) in several disorders including Parkinson's disease (PD) and dementia with Lewy bodies (DLB). Most previous SPECT studies have adopted region of interest (ROI) methods for analysis, which are subjective and operator-dependent. The purpose of this study was to investigate differences in striatal binding of (123)I-FP-CIT SPECT using the automated technique of statistical parametric mapping (SPM99) in subjects with DLB, Alzheimer's disease (AD), PD and healthy age-matched controls. This involved spatial normalisation of each subject's image to a customised template, followed by smoothing and intensity normalisation of each image to its corresponding mean occipital count per voxel. Group differences were assessed using a two-sample t test. Applying a height threshold of P

Comparison of Arterial Spin-labeling Perfusion Images at Different Spatial Normalization Methods Based on Voxel-based Statistical Analysis.

PubMed

Tani, Kazuki; Mio, Motohira; Toyofuku, Tatsuo; Kato, Shinichi; Masumoto, Tomoya; Ijichi, Tetsuya; Matsushima, Masatoshi; Morimoto, Shoichi; Hirata, Takumi

2017-01-01

Spatial normalization is a significant image pre-processing operation in statistical parametric mapping (SPM) analysis. The purpose of this study was to clarify the optimal method of spatial normalization for improving diagnostic accuracy in SPM analysis of arterial spin-labeling (ASL) perfusion images. We evaluated the SPM results of five spatial normalization methods obtained by comparing patients with Alzheimer's disease or normal pressure hydrocephalus complicated with dementia and cognitively healthy subjects. We used the following methods: 3DT1-conventional based on spatial normalization using anatomical images; 3DT1-DARTEL based on spatial normalization with DARTEL using anatomical images; 3DT1-conventional template and 3DT1-DARTEL template, created by averaging cognitively healthy subjects spatially normalized using the above methods; and ASL-DARTEL template created by averaging cognitively healthy subjects spatially normalized with DARTEL using ASL images only. Our results showed that ASL-DARTEL template was small compared with the other two templates. Our SPM results obtained with ASL-DARTEL template method were inaccurate. Also, there were no significant differences between 3DT1-conventional and 3DT1-DARTEL template methods. In contrast, the 3DT1-DARTEL method showed higher detection sensitivity, and precise anatomical location. Our SPM results suggest that we should perform spatial normalization with DARTEL using anatomical images.

Progress on Poverty? New Estimates of Historical Trends Using an Anchored Supplemental Poverty Measure.

PubMed

Wimer, Christopher; Fox, Liana; Garfinkel, Irwin; Kaushal, Neeraj; Waldfogel, Jane

2016-08-01

This study examines historical trends in poverty using an anchored version of the U.S. Census Bureau's recently developed Research Supplemental Poverty Measure (SPM) estimated back to 1967. Although the SPM is estimated each year using a quasi-relative poverty threshold that varies over time with changes in families' expenditures on a core basket of goods and services, this study explores trends in poverty using an absolute, or anchored, SPM threshold. We believe the anchored measure offers two advantages. First, setting the threshold at the SPM's 2012 levels and estimating it back to 1967, adjusted only for changes in prices, is more directly comparable to the approach taken in official poverty statistics. Second, it allows for a better accounting of the roles that social policy, the labor market, and changing demographics play in trends in poverty rates over time, given that changes in the threshold are held constant. Results indicate that unlike official statistics that have shown poverty rates to be fairly flat since the 1960s, poverty rates have dropped by 40 % when measured using a historical anchored SPM over the same period. Results obtained from comparing poverty rates using a pretax/pretransfer measure of resources versus a post-tax/post-transfer measure of resources further show that government policies, not market incomes, are driving the declines observed over time.

The Relationship between Polyamines and Hormones in the Regulation of Wheat Grain Filling

PubMed Central

Liu, Yang; Gu, Dandan; Wu, Wei; Wen, Xiaoxia; Liao, Yuncheng

2013-01-01

The grain weight of wheat is strongly influenced by filling. Polyamines (PA) are involved in regulating plant growth. However, the effects of PA on wheat grain filling and its mechanism of action are unclear. The objective of the present study was to investigate the relationship between PAs and hormones in the regulation of wheat grain filling. Three PAs, spermidine (Spd), spermine (Spm), and putrescine (Put), were exogenously applied, and the grain filling characteristics and changes in endogenous PA and hormones, i.e., indole-3-acetic acid (IAA), zeatin (Z) + zeatin riboside (ZR), abscisic acid (ABA), ethylene (ETH) and gibberellin 1+4 (GAs), were quantified during wheat grain filling. Exogenous applications of Spd and Spm significantly increased the grain filling rate and weight, but exogenous Put had no significant effects on these measures. Exogenous Spd and Spm significantly increased the endogenous Spd, Spm, Z+ZR, ABA, and IAA contents and significantly decreased ETH evolution in grains. The endogenous Spd, Spm and Z+ZR contents were positively and significantly correlated with the grain filling rate and weight of wheat, and the endogenous ETH evolution was negatively and significantly correlated with the wheat grain filling rate and weight. Based upon these results, we concluded that PAs were involved in the balance of hormones that regulated the grain filling of wheat. PMID:24205154

Similar survival of patients with multiple versus single primary melanomas based on Utah Surveillance, Epidemiology, and End Results data (1973-2011).

PubMed

Grossman, Douglas; Farnham, James M; Hyngstrom, John; Klapperich, Marki E; Secrest, Aaron M; Empey, Sarah; Bowen, Glen M; Wada, David; Andtbacka, Robert H I; Grossmann, Kenneth; Bowles, Tawnya L; Cannon-Albright, Lisa A

2018-03-01

Survival data are mixed comparing patients with multiple primary melanomas (MPM) to those with single primary melanomas (SPM). We compared MPM versus SPM patient survival using a matching method that avoids potential biases associated with other analytic approaches. Records of 14,138 individuals obtained from the Surveillance, Epidemiology, and End Results registry of all melanomas diagnosed or treated in Utah between 1973 and 2011 were reviewed. A single matched control patient was selected randomly from the SPM cohort for each MPM patient, with the restriction that they survived at least as long as the interval between the first and second diagnoses for the matched MPM patient. Survival curves (n = 887 for both MPM and SPM groups) without covariates showed a significant survival disadvantage for MPM patients (chi-squared 39.29, P < .001). However, a multivariate Cox proportional hazards model showed no significant survival difference (hazard ratio 1.07, P = .55). Restricting the multivariate analysis to invasive melanomas also showed no significant survival difference (hazard ratio 0.99, P = .96). Breslow depth, ulceration status, and specific cause of death were not available for all patients. Patients with MPM had similar survival times as patients with SPM. Copyright © 2018 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.

Design and fabrication of nanoelectrodes for applications with scanning electrochemical microscopy

NASA Astrophysics Data System (ADS)

Thakar, Rahul

Scanning electrochemical microscope (SECM) was introduced two decades ago and has since emerged as a powerful research tool to investigate localized electrochemical reactions at the surface of material and biological samples. The ability to obtain chemical information at a surface differentiates SECM from competing scanning probe microscopy (SPM) techniques. Although, chemical specificity is a unique advantage offered by SECM, inherent limitations due to a slow feedback response, and challenges associated with production of smaller electrodes have remained major drawbacks. Initially in this research, SECM was utilized as a characterization and investigative tool. Later, advances in SECM imaging were achieved with design and production of multifunctional nanoelectrodes. At first, platinum based nanoelectrodes were fabricated for use as electrochemical probes to investigate local electron transfer at chemically-modified surfaces. Further, micron and sub-micron platinum electrodes with chemically modified shrouds were prepared and characterized with voltammetric measurements. Studies reveal experimental evidence for the presence of edge-effects that are typically associated with submicron electrodes. Interestingly, we observed selectivity of these electrodes based on hydrophobic/ hydrophilic character. Through vapor deposition of parylene over microstructured material, single-pore membranes and porous membrane arrays were produced. Pore size characterization within porous membranes was performed with templated growth of micro/nanostructures. Characterization of transport properties of ions and redox-active molecules through hydrophobic parylene membranes was investigated with ion conductance microscopy and SECM, individually. Parylene is an insulative material that is chemically resistant, deposits conformally over high-aspect ratio objects and also converts into conductive carbon at high-temperature pyrolysis. Motivated by these results we identified a unique strategy to fabricate parylene based carbon electrodes Here, we have developed a unique strategy to obtain carbon based nanoelectrodes from vapor deposition of parylene over pulled glass nanopipettes. With this approach, multiple electrode geometries were constructed and the application of individual geomtery with SECM is demonstrated. In particular, enhanced spatial resolution and electrochemical information were obtained with the use of carbon ring/nanopore electrodes. Practical implications of edge-effects observed with carbon ring/nanopore electrodes is discussed with substrate generation tip collection (SG/TC) SECM Carbon ring/nanopore electrodes have also enabled the use of SECM in conjunction with ion conductance microscopy to alleviate the issue of poor feedback response. This has further helped in deconvolution of electrochemcial and topographical signals. Although, use of carbon nanoelectrodes is discussed with specific applications to electrochemcial microscopy, these probes have wide utility in electroanalytical applications. Initial proof-of-concept experiments along with future directions for this work are presented.

A simple method of equine limb force vector analysis and its potential applications.

PubMed

Hobbs, Sarah Jane; Robinson, Mark A; Clayton, Hilary M

2018-01-01

Ground reaction forces (GRF) measured during equine gait analysis are typically evaluated by analyzing discrete values obtained from continuous force-time data for the vertical, longitudinal and transverse GRF components. This paper describes a simple, temporo-spatial method of displaying and analyzing sagittal plane GRF vectors. In addition, the application of statistical parametric mapping (SPM) is introduced to analyse differences between contra-lateral fore and hindlimb force-time curves throughout the stance phase. The overall aim of the study was to demonstrate alternative methods of evaluating functional (a)symmetry within horses. GRF and kinematic data were collected from 10 horses trotting over a series of four force plates (120 Hz). The kinematic data were used to determine clean hoof contacts. The stance phase of each hoof was determined using a 50 N threshold. Vertical and longitudinal GRF for each stance phase were plotted both as force-time curves and as force vector diagrams in which vectors originating at the centre of pressure on the force plate were drawn at intervals of 8.3 ms for the duration of stance. Visual evaluation was facilitated by overlay of the vector diagrams for different limbs. Summary vectors representing the magnitude (VecMag) and direction (VecAng) of the mean force over the entire stance phase were superimposed on the force vector diagram. Typical measurements extracted from the force-time curves (peak forces, impulses) were compared with VecMag and VecAng using partial correlation (controlling for speed). Paired samples t -tests (left v. right diagonal pair comparison and high v. low vertical force diagonal pair comparison) were performed on discrete and vector variables using traditional methods and Hotelling's T 2 tests on normalized stance phase data using SPM. Evidence from traditional statistical tests suggested that VecMag is more influenced by the vertical force and impulse, whereas VecAng is more influenced by the longitudinal force and impulse. When used to evaluate mean data from the group of ten sound horses, SPM did not identify differences between the left and right contralateral limb pairs or between limb pairs classified according to directional asymmetry. When evaluating a single horse, three periods were identified during which differences in the forces between the left and right forelimbs exceeded the critical threshold ( p  < .01). Traditional statistical analysis of 2D GRF peak values, summary vector variables and visual evaluation of force vector diagrams gave harmonious results and both methods identified the same inter-limb asymmetries. As alpha was more tightly controlled using SPM, significance was only found in the individual horse although T 2 plots followed the same trends as discrete analysis for the group. The techniques of force vector analysis and SPM hold promise for investigations of sidedness and asymmetry in horses.

Inorganic PM in poultry house using rice hull bedding

USDA-ARS?s Scientific Manuscript database

The persistence and long life expectancy of ammonia, odors and toxic pollutants from poultry houses may be due to the ability of suspended particulate matters (SPM) to serve as carriers for odorous compounds such as ammonium ions and volatile organic compounds. SPM is generated from the feed, anima...

Flight Model Discharge System

DTIC Science & Technology

1989-09-01

Itterconnection wiring diagram for the ESA ............................... 34 3-13 Typical gain versus total count curve for CEM...42 3-16 Calibration curve for energy bin 12 of the ion ESA ....................... 43 3-17 Flight ESA S/N001...Calibration curves for SPM S/N001 ......................................... 67 4-11 Calibration curves for SPM S/N002

Capturing the Surface Texture and Shape of Pollen: A Comparison of Microscopy Techniques

PubMed Central

Sivaguru, Mayandi; Mander, Luke; Fried, Glenn; Punyasena, Surangi W.

2012-01-01

Research on the comparative morphology of pollen grains depends crucially on the application of appropriate microscopy techniques. Information on the performance of microscopy techniques can be used to inform that choice. We compared the ability of several microscopy techniques to provide information on the shape and surface texture of three pollen types with differing morphologies. These techniques are: widefield, apotome, confocal and two-photon microscopy (reflected light techniques), and brightfield and differential interference contrast microscopy (DIC) (transmitted light techniques). We also provide a first view of pollen using super-resolution microscopy. The three pollen types used to contrast the performance of each technique are: Croton hirtus (Euphorbiaceae), Mabea occidentalis (Euphorbiaceae) and Agropyron repens (Poaceae). No single microscopy technique provided an adequate picture of both the shape and surface texture of any of the three pollen types investigated here. The wavelength of incident light, photon-collection ability of the optical technique, signal-to-noise ratio, and the thickness and light absorption characteristics of the exine profoundly affect the recovery of morphological information by a given optical microscopy technique. Reflected light techniques, particularly confocal and two-photon microscopy, best capture pollen shape but provide limited information on very fine surface texture. In contrast, transmitted light techniques, particularly differential interference contrast microscopy, can resolve very fine surface texture but provide limited information on shape. Texture comprising sculptural elements that are spaced near the diffraction limit of light (∼250 nm; NDL) presents an acute challenge to optical microscopy. Super-resolution structured illumination microscopy provides data on the NDL texture of A. repens that is more comparable to textural data from scanning electron microscopy than any other optical microscopy technique investigated here. Maximizing the recovery of morphological information from pollen grains should lead to more robust classifications, and an increase in the taxonomic precision with which ancient vegetation can be reconstructed. PMID:22720050

Radio frequency elevator for a pulsed positron beam

NASA Astrophysics Data System (ADS)

Dickmann, Marcel; Mitteneder, Johannes; Kögel, Gottfried; Egger, Werner; Sperr, Peter; Ackermann, Ulrich; Piochacz, Christian; Dollinger, Günther

2016-06-01

An elevator increases the potential energy of a particle beam with respect to ground potential without any alteration of kinetic energy and other beam parameters. This elevator is necessary for the implementation of the Munich Scanning Positron Microscope (SPM) at the intense positron source NEPOMUC at the research reactor FRM II in Munich. The principles of the rf elevator for pure electrostatically guided positrons are described. Measurements of beam quality behind the elevator are reported, which confirm that after the implementation of elevator and SPM at NEPOMUC the SPM can be operated at a considerably improved resolution (~ 0.3 μm) and event rate (~3.7 kHz) compared to the laboratory based β+-source.

Effect of Feeding Schedule on Fractionated Particulate Matter Distribution in Rooster House

USDA-ARS?s Scientific Manuscript database

The persistence and long life expectancy of ammonia, odors and toxic pollutants from poultry houses may be due to the ability of suspended particulate matters (SPM) to serve as carriers for odorous compounds such as ammonium ions and volatile organic compounds. SPM is generated from the feed, anima...

Dysgenic Fertility, Intelligence and Family Size in Libya

ERIC Educational Resources Information Center

Al-Shahomee, Alsedig Abdalgadr; Lynn, Richard; Abdalla, Saleh El-ghmary

2013-01-01

The Standard Progressive Matrices (SPM) was administered to a sample of 592 16 year old school students in Libya. There was a small negative correlation of -0.14 between SPM scores and the number of siblings, indicating only marginal dysgenic fertility. Supplementary material giving the data is given online. (Contains 1 table.)

Experimental Evaluation of a Serious Game for Teaching Software Process Modeling

ERIC Educational Resources Information Center

Chaves, Rafael Oliveira; von Wangenheim, Christiane Gresse; Furtado, Julio Cezar Costa; Oliveira, Sandro Ronaldo Bezerra; Santos, Alex; Favero, Eloi Luiz

2015-01-01

Software process modeling (SPM) is an important area of software engineering because it provides a basis for managing, automating, and supporting software process improvement (SPI). Teaching SPM is a challenging task, mainly because it lays great emphasis on theory and offers few practical exercises. Furthermore, as yet few teaching approaches…

Trends and the effect of management on macronutrients in fractionated particulate matter in rooster house

USDA-ARS?s Scientific Manuscript database

The persistence and long life expectancy of ammonia, odors and toxic pollutants from poultry houses may be due to the ability of suspended particulate matters (SPM) to serve as carriers for odorous compounds such as ammonium ions and volatile organic compounds. SPM is generated from the feed, anima...

Visualizing Confidence Bands for Semiparametrically Estimated Nonlinear Relations among Latent Variables

ERIC Educational Resources Information Center

Pek, Jolynn; Chalmers, R. Philip; Kok, Bethany E.; Losardo, Diane

2015-01-01

Structural equation mixture models (SEMMs), when applied as a semiparametric model (SPM), can adequately recover potentially nonlinear latent relationships without their specification. This SPM is useful for exploratory analysis when the form of the latent regression is unknown. The purpose of this article is to help users familiar with structural…

Considering the Spatial Layout Information of Bag of Features (BoF) Framework for Image Classification.

PubMed

Mu, Guangyu; Liu, Ying; Wang, Limin

2015-01-01

The spatial pooling method such as spatial pyramid matching (SPM) is very crucial in the bag of features model used in image classification. SPM partitions the image into a set of regular grids and assumes that the spatial layout of all visual words obey the uniform distribution over these regular grids. However, in practice, we consider that different visual words should obey different spatial layout distributions. To improve SPM, we develop a novel spatial pooling method, namely spatial distribution pooling (SDP). The proposed SDP method uses an extension model of Gauss mixture model to estimate the spatial layout distributions of the visual vocabulary. For each visual word type, SDP can generate a set of flexible grids rather than the regular grids from the traditional SPM. Furthermore, we can compute the grid weights for visual word tokens according to their spatial coordinates. The experimental results demonstrate that SDP outperforms the traditional spatial pooling methods, and is competitive with the state-of-the-art classification accuracy on several challenging image datasets.

Hedonic approaches based on spatial econometrics and spatial statistics: application to evaluation of project benefits

NASA Astrophysics Data System (ADS)

Tsutsumi, Morito; Seya, Hajime

2009-12-01

This study discusses the theoretical foundation of the application of spatial hedonic approaches—the hedonic approach employing spatial econometrics or/and spatial statistics—to benefits evaluation. The study highlights the limitations of the spatial econometrics approach since it uses a spatial weight matrix that is not employed by the spatial statistics approach. Further, the study presents empirical analyses by applying the Spatial Autoregressive Error Model (SAEM), which is based on the spatial econometrics approach, and the Spatial Process Model (SPM), which is based on the spatial statistics approach. SPMs are conducted based on both isotropy and anisotropy and applied to different mesh sizes. The empirical analysis reveals that the estimated benefits are quite different, especially between isotropic and anisotropic SPM and between isotropic SPM and SAEM; the estimated benefits are similar for SAEM and anisotropic SPM. The study demonstrates that the mesh size does not affect the estimated amount of benefits. Finally, the study provides a confidence interval for the estimated benefits and raises an issue with regard to benefit evaluation.

Cyclobutanone Mimics of Intermediates in Metallo-β-Lactamase Catalysis.

PubMed

Abboud, Martine I; Kosmopoulou, Magda; Krismanich, Anthony P; Johnson, Jarrod W; Hinchliffe, Philip; Brem, Jürgen; Claridge, Timothy D W; Spencer, James; Schofield, Christopher J; Dmitrienko, Gary I

2018-04-17

The most important resistance mechanism to β-lactam antibiotics involves hydrolysis by two β-lactamase categories: the nucleophilic serine and the metallo-β-lactamases (SBLs and MBLs, respectively). Cyclobutanones are hydrolytically stable β-lactam analogues with potential to inhibit both SBLs and MBLs. We describe solution and crystallographic studies on the interaction of a cyclobutanone penem analogue with the clinically important MBL SPM-1. NMR experiments using 19 F-labeled SPM-1 imply the cyclobutanone binds to SPM-1 with micromolar affinity. A crystal structure of the SPM-1:cyclobutanone complex reveals binding of the hydrated cyclobutanone through interactions with one of the zinc ions, stabilisation of the hydrate by hydrogen bonding to zinc-bound water, and hydrophobic contacts with aromatic residues. NMR analyses using a 13 C-labeled cyclobutanone support assignment of the bound species as the hydrated ketone. The results inform on how MBLs bind substrates and stabilize tetrahedral intermediates. They support further investigations on the use of transition-state and/or intermediate analogues as inhibitors of all β-lactamase classes. © 2018 Die Autoren. Veröffentlicht von Wiley-VCH Verlag GmbH & Co. KGaA.

The Absolute Proper Motion of NGC 6397 Revisited

NASA Astrophysics Data System (ADS)

Rees, Richard; Cudworth, Kyle

2018-01-01

We compare several determinations of the absolute proper motion of the Galactic globular cluster NGC 6397: (1) our own determination relative to field stars derived from scans of 38 photographic plates spanning 97 years in epoch; (2) using our proper motion membership to identify cluster stars in various catalogs in the literature (UCAC4, UCAC5, PPMXL, HSOY, Tycho-2, Hipparcos, TGAS); (3) published results from the Yale SPM Program (both tied to Hipparcos and relative to galaxies) and two from HST observations relative to galaxies. The various determinations are not in good agreement. Curiously, the Yale SPM relative to galaxies does not agree with the HST determinations, and the individual HST error ellipses are close to each other but do not overlap. The Yale SPM relative to galaxies does agree with our determination, Tycho-2, and the Yale SPM tied to Hipparcos. It is not clear which of the current determinations is most reliable; we have found evidence of systematic errors in some of them (including one of the HST determinations). This research has been partially supported by the NSF.

Molecular epidemiology of SPM-1-producing Pseudomonas aeruginosa by rep-PCR in hospitals in Parana, Brazil.

PubMed

Kalluf, K O; Arend, L N; Wuicik, T E; Pilonetto, M; Tuon, F F

2017-04-01

Infections caused by multidrug resistant microorganisms are a global health problem, and Pseudomonas aeruginosa is an important nosocomial pathogen, easily disseminated in the hospital environment. The aim of this study was to determine SPM-1 in P. aeruginosa strains in 30 Brazilian hospitals and the genetic similarity of isolates. We analyzed 161 isolates of carbapenem-resistant P. aeruginosa. Imipenem/EDTA and imipenem strip were used for phenotypic detection of MBL production; and real-time polymerase chain reaction (PCR) for genetic detection. Genetic similarity was determined by rep-PCR. We obtained 136/161 (84.5%) isolates with positive phenotypic result for metallo-β-lactamase (MBL) and the bla SPM-1 gene was identified in 41 isolates. There was a predominant profile (>95% of genetic similarity) in 92.7% of isolates. This predominant profile was widely disseminated in Paraná state. SPM-1 is the main MBL identified in carbapenem-resistant P. aeruginosa in Southern Brazil. The genetic similarity among some isolates suggests a clonal expansion. Copyright © 2016 Elsevier B.V. All rights reserved.

Concentration of biologically active polyamines in rabbit meat, liver and kidney after slaughter and their changes during meat storage and cooking.

PubMed

Dadáková, Eva; Pelikánová, Tamara; Kalač, Pavel

2012-03-01

The concentration of putrescine (PUT), spermidine (SPD) and spermine (SPM) was determined in chilled meat and kidneys of 18 rabbits and in liver of 12 animals 24h after slaughter. Very low PUT concentrations were detected only in kidneys. Mean SPD levels were 2.2, 2.2, 61.7 and 32.7mgkg(-1) in saddle, leg, liver and kidneys, respectively. The respective SPM concentrations were 14.7, 8.0, 115 and 88.4mgkg(-1). SPD and SPM losses of about one third of the initial levels were apparent in saddles stored at -18°C for 8months. Losses of both polyamines of about 15-20% of the initial concentrations were found in saddles stored aerobically at +2°C for up to 9days. Stewing of saddles caused significant SPD and SPM losses of about 20-25%, while upon roasting and pan-roasting without oil a decrease of about 50% of the initial concentration was observed. Copyright © 2011 Elsevier Ltd. All rights reserved.

SPM-Twin Telescopes: Project Overview

NASA Astrophysics Data System (ADS)

González, J. J.

2007-06-01

The SPM-Twin Project is an international initiative for a pair of 6.5-m telescopes, at the San Pedro Mártir Observatory (SPM), to provide a limber, and highly competitive, platform for discovery by focusing on scientific niches technically difficult for existing or planned larger aperture telescopes, and by exploiting the superiority of the SPM site. The telescopes are based on the proven and highly efficient Magellan concept, but each with a distinct optimization to cover two complementary but mutually exclusive aspects: (a) the "Standard Field Telescope" would have a field of view of 15'- 30', capable of observing in the optical through the thermal infrared (0.4 - 24 μm) and prepared for adaptive optics, and (b) the "Wide Field Telescope" (WFT) with a field of view of 1.5° or more, capable of multi-object fiber spectroscopy, integral field unit (IFU) spectroscopy, and potentially narrow-band imaging as well. The WFT spectroscopy would extend from 0.36 to 1.8 μm, and would contain several thousand fibers. We present a general overview of the project.

Protective Action of Spermine and Spermidine against Photoinhibition of Photosystem I in Isolated Thylakoid Membranes

PubMed Central

Yaakoubi, Hnia; Hamdani, Saber; Bekalé, Laurent; Carpentier, Robert

2014-01-01

The photo-stability of photosystem I (PSI) is of high importance for the photosynthetic processes. For this reason, we studied the protective action of two biogenic polyamines (PAs) spermine (Spm) and spermidine (Spd) on PSI activity in isolated thylakoid membranes subjected to photoinhibition. Our results show that pre-loading thylakoid membranes with Spm and Spd reduced considerably the inhibition of O2 uptake rates, P700 photooxidation and the accumulation of superoxide anions (O2 −) induced by light stress. Spm seems to be more effective than Spd in preserving PSI photo-stability. The correlation of the extent of PSI protection, photosystem II (PSII) inhibition and O2 − generation with increasing Spm doses revealed that PSI photo-protection is assumed by two mechanisms depending on the PAs concentration. Given their antioxidant character, PAs scavenge directly the O2 − generated in thylakoid membranes at physiological concentration (1 mM). However, for non-physiological concentration, the ability of PAs to protect PSI is due to their inhibitory effect on PSII electron transfer. PMID:25420109

Spermine modulates the expression of two probable polyamine transporter genes and determines growth responses to cadaverine in Arabidopsis.

PubMed

Sagor, G H M; Berberich, Thomas; Kojima, Seiji; Niitsu, Masaru; Kusano, Tomonobu

2016-06-01

Two genes, LAT1 and OCT1 , are likely to be involved in polyamine transport in Arabidopsis. Endogenous spermine levels modulate their expression and determine the sensitivity to cadaverine. Arabidopsis spermine (Spm) synthase (SPMS) gene-deficient mutant was previously shown to be rather resistant to the diamine cadaverine (Cad). Furthermore, a mutant deficient in polyamine oxidase 4 gene, accumulating about twofold more of Spm than wild type plants, showed increased sensitivity to Cad. It suggests that endogenous Spm content determines growth responses to Cad in Arabidopsis thaliana. Here, we showed that Arabidopsis seedlings pretreated with Spm absorbs more Cad and has shorter root growth, and that the transgenic Arabidopsis plants overexpressing the SPMS gene are hypersensitive to Cad, further supporting the above idea. The transgenic Arabidopsis overexpressing L-Amino acid Transporter 1 (LAT1) absorbed more Cad and showed increased Cad sensitivity, suggesting that LAT1 functions as a Cad importer. Recently, other research group reported that Organic Cation Transporter 1 (OCT1) is a causal gene which determines the Cad sensitivity of various Arabidopsis accessions. Furthermore, their results suggested that OCT1 is involved in Cad efflux. Thus we monitored the expression of OCT1 and LAT1 during the above experiments. Based on the results, we proposed a model in which the level of Spm content modulates the expression of OCT1 and LAT1, and determines Cad sensitivity of Arabidopsis.

Compensation for the phase-type spatial periodic modulation of the near-field beam at 1053 nm

NASA Astrophysics Data System (ADS)

Gao, Yaru; Liu, Dean; Yang, Aihua; Tang, Ruyu; Zhu, Jianqiang

2017-10-01

A phase-only spatial light modulator is used to provide and compensate for the spatial periodic modulation (SPM) of the near-field beam at the near infrared at 1053nm wavelength with an improved iterative weight-based method. The transmission characteristics of the incident beam has been changed by a spatial light modulator (SLM) to shape the spatial intensity of the output beam. The propagation and reverse propagation of the light in free space are two important processes in the iterative process. The based theory is the beam angular spectrum transmit formula (ASTF) and the principle of the iterative weight-based method. We have made two improvements to the originally proposed iterative weight-based method. We select the appropriate parameter by choosing the minimum value of the output beam contrast degree and use the MATLAB built-in angle function to acquire the corresponding phase of the light wave function. The required phase that compensates for the intensity distribution of the incident SPM beam is iterated by this algorithm, which can decrease the magnitude of the SPM of the intensity on the observation plane. The experimental results show that the phase-type SPM of the near-field beam is subject to a certain restriction. We have also analyzed some factors that make the results imperfect. The experiment results verifies the possible applicability of this iterative weight-based method to compensate for the SPM of the near-field beam.

Differential growth forms of the sponge Biemna fortis govern the abundance of its associated brittle star Ophiactis modesta

NASA Astrophysics Data System (ADS)

Dahihande, Azraj S.; Thakur, Narsinh L.

2017-08-01

Marine intertidal regions are physically stressful habitats. In such an environment, facilitator species and positive interactions mitigate unfavorable conditions to the benefit of less tolerant organisms. In sponge-brittle star association, sponges effectively shelter brittle stars from biotic and abiotic stresses. The sponge, Biemna fortis (Topsent, 1897) was examined from two intertidal regions Anjuna and Mhapan along the Central West Coast of India for associated brittle star Ophiactis modesta (Brock, 1888) during 2013-2014. The study sites varied in suspended particulate matter (SPM). B. fortis at the high SPM habitat (Anjuna) had partially buried growth form and at the low SPM habitat (Mhapan) had massive growth form. O. modesta was abundantly associated with the massive growth form (50-259 individuals per 500 ml sponge) but rarely occurred in association with partially buried growth form (6-16 individuals per 500 ml sponge). In laboratory choice assay O. modesta showed equal preference to the chemical cues from both the growth forms of B. fortis. In addition, O. modesta showed significant preference to B. fortis compared to other sympatric sponges. These observations highlight the involvement of chemical cues in host recognition by O. modesta. Massive growth forms transplanted to the high SPM habitat were unable to survive but partially buried growth forms transplanted to the low SPM habitat were able to survive. Differential growth forms of the host sponge B. fortis at different abiotic stresses affect the abundance of the associated brittle star O. modesta.

Oil sands process-affected water impairs feeding by Daphnia magna.

PubMed

Lari, Ebrahim; Steinkey, Dylan; Morandi, Garrett; Rasmussen, Joseph B; Giesy, John P; Pyle, Greg G

2017-05-01

Growth in extraction of bitumen from oil sands has raised concerns about influences of this industry on surrounding environments. Water clearance rate (a surrogate of feeding rate by Daphnia magna) in water containing D. magna exposed to oil sands process-affected water (OSPW) and its principal components, dissolved component (DC) and suspended particulate matter (SPM), was reduced to 72, 29, and 59% of controls, respectively. This study also examined several possible mechanisms for the observed changes algal cell density (i.e., feeding rate). There was no change in the digestive enzymes trypsin or amylase when D. magna were exposed to DC or SPM; however, exposure to total OSPW reduced trypsin activity. Mandible rolling or post-abdominal rejections, which are indicators of feeding and palatability of food, were not affected by any exposures to OSPW. Beating of thoracic limbs, which provides water flow toward the feeding groove, was reduced by exposure to SPM or total OSPW. Peristaltic activity was reduced by exposure to DC, which then might result in reduced digestion time in D. magna exposed to DC, SPM or whole OSPW. All treatments caused an increase in numbers of intact algae cells in the hindgut and excreted material. These results suggest that both DC and SPM affect feeding of D. magna by impairing actions of the digestive system, but most probably not by reducing rates of ingestion. Copyright © 2017 Elsevier Ltd. All rights reserved.

Variability in the fractionation of stable isotopes during degradation of two intertidal red algae

NASA Astrophysics Data System (ADS)

Hill, Jaclyn M.; McQuaid, Christopher D.

2009-04-01

Macroalgae contribute to intertidal food webs primarily as detritus, with unclear implications for food web studies using stable isotope analysis. We examined differences in the thallus parts of two South African rhodophytes ( Gelidium pristoides and Hypnea spicifera) and changes in overall δ13C, δ15N signatures and C:N ratios during degradation in both the field and laboratory. We hypothesized that both degrading macroalgal tissue and macroalgal-derived suspended particulate material (SPM) would show negligible changes in δ13C, but enriched δ15N signatures and lower C:N ratios relative to healthy plants. Only C:N laboratory ratios conformed to predictions, with both species of macroalgae showing decomposition related changes in δ13C and significant depletions in δ15N in both the field and laboratory. In the laboratory, algal tissue and SPM from each species behaved similarly (though some effects were non-significant) but with differing strengths. Gelidium pristoides δ13C increased and C:N ratios decreased over time in tissue and SPM; δ15N became depleted only in SPM. Hypnea spicifera, δ13C, δ15N and C:N ratios all decreased during degradation in both SPM and algae. Over 60 days in the field, δ13C was depleted in both species (1-2‰) and in naturally senescent Gelidium pristoides fronds. δ15N was depleted in Hypnea spicifera (approx. 1‰), while C:N ratios of both species were unaffected. The two species differed in δ13C, δ15N and C:N after degradation, but only in C:N beforehand. We suggest isotope changes in the laboratory mainly reflect microbial effects, while in the field these are combined with leaching due to constant water replenishment and agitation. Differences between these two species in the isotope responses to degradation highlight the difficulty of linking the signature of SPM to its multiple sources.

Leveraging Clinical Imaging Archives for Radiomics: Reliability of Automated Methods for Brain Volume Measurement.

PubMed

Adduru, Viraj R; Michael, Andrew M; Helguera, Maria; Baum, Stefi A; Moore, Gregory J

2017-09-01

Purpose To validate the use of thick-section clinically acquired magnetic resonance (MR) imaging data for estimating total brain volume (TBV), gray matter (GM) volume (GMV), and white matter (WM) volume (WMV) by using three widely used automated toolboxes: SPM ( www.fil.ion.ucl.ac.uk/spm/ ), FreeSurfer ( surfer.nmr.mgh.harvard.edu ), and FSL (FMRIB software library; Oxford Centre for Functional MR Imaging of the Brain, Oxford, England, https://fsl.fmrib.ox.ac.uk/fsl ). Materials and Methods MR images from a clinical archive were used and data were deidentified. The three methods were applied to estimate brain volumes from thin-section research-quality brain MR images and routine thick-section clinical MR images acquired from the same 38 patients (age range, 1-71 years; mean age, 22 years; 11 women). By using these automated methods, TBV, GMV, and WMV were estimated. Thin- versus thick-section volume comparisons were made for each method by using intraclass correlation coefficients (ICCs). Results SPM exhibited excellent ICCs (0.97, 0.85, and 0.83 for TBV, GMV, and WMV, respectively). FSL exhibited ICCs of 0.69, 0.51, and 0.60 for TBV, GMV, and WMV, respectively, but they were lower than with SPM. FreeSurfer exhibited excellent ICC of 0.63 only for TBV. Application of SPM's voxel-based morphometry on the modulated images of thin-section images and interpolated thick-section images showed fair to excellent ICCs (0.37-0.98) for the majority of brain regions (88.47% [306924 of 346916 voxels] of WM and 80.35% [377 282 of 469 502 voxels] of GM). Conclusion Thick-section clinical-quality MR images can be reliably used for computing quantitative brain metrics such as TBV, GMV, and WMV by using SPM. © RSNA, 2017 Online supplemental material is available for this article.

Polychlorinated diphenyl ethers (PCDEs) in surface sediments, suspended particulate matter (SPM) and surface water of Chaohu Lake, China.

PubMed

Zhang, Xuesheng; Wang, Tantan; Gao, Lei; Feng, Mingbao; Qin, Li; Shi, Jiaqi; Cheng, Danru

2018-05-31

Polychlorinated diphenyl ethers (PCDEs) are typical halogenated aromatic pollutants that have shown various toxicological effects on organisms. However, the contamination status of PCDEs in the fresh water lakes of China remains poorly researched. In this study, the levels of 15 congeners of PCDEs in the sediments, suspended particulate matter (SPM) and water of Chaohu Lake were determined. The results showed that the ranges of concentrations of total PCDEs (ΣPCDEs) in the sediment, SPM and water were 0.279 ng g -1 dry weight (d.w.)-2.474 ng g -1 d.w., 0.331 ng g -1 d.w.-2.013 ng g -1 d.w. and 0.351 ng L -1 -2.021 ng L -1 , respectively. The most abundant congeners found in sediments, SPM and water were 3,3',4,4'-tetra-CDE, deca-CDE and 2,4,6-tri-CDE, with average contributive ratios of 17.36%, 15.48% and 20.63%, respectively. The medium and higher chlorinated PCDEs (e.g., penta- and deca-CDEs) were the dominant congeners in sediments and SPM. The percentages of lower chlorinated PCDEs (e.g., tri-CDEs) in the water were higher than those in the sediments. The combined input of ΣPCDEs from the eight main tributaries to Chaohu Lake was estimated at 6.94 kg y -1 . Strong linear correlations between the concentrations of ΣPCDEs and organic carbon (OC) contents in three type samples from Chaohu Lake suggested OC could influence the distribution of PCDEs in Chaohu Lake substantially. In addition, the calculated average organic carbon normalized partition coefficients (logK oc ) of 15 PCDEs between water and SPM were in the range of 4.55-5.45 mL g -1 . This study confirmed that Chaohu Lake is contaminated by PCDEs. Copyright © 2018 Elsevier Ltd. All rights reserved.

A Population-Based Study of Subsequent Primary Malignancies After Endometrial Cancer: Genetic, Environmental, and Treatment-Related Associations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, Aaron P.; Neeley, E. Shannon; Werner, Theresa

2010-09-01

Purpose: To examine the risk of subsequent primary malignancies (SPMs) in women diagnosed with endometrial cancer. Methods and Materials: The National Cancer Institute's Survival, Epidemiology, and End Results database was used to determine the risk of SPM after endometrial cancer in 69,739 women diagnosed between 1973 and 2005. Standardized incidence ratios were calculated (observed/expected [O/E]) for SPM sites. Results: Median follow-up was 11.2 years, representing 757,567 person-years of follow-up. The risk of SPM was significantly increased for small intestine (O/E = 1.48; 99% confidence interval [CI], 1.03-2.05), colon (O/E = 1.16; CI, 1.09-1.24), vagina (O/E = 2.71; CI, 1.86-3.8), andmore » urinary bladder (O/E = 1.41; CI, 1.25-1.59) SPMs and decreased for oral cavity and pharynx (O/E = 0.75; CI, 0.6-0.93), lung and bronchus (O/E = 0.78; CI, 0.72-0.84), and esophagus (O/E = 0.58; CI, 0.37-0.86) SPMs. Patients receiving external-beam radiotherapy for endometrial cancer had an increased risk of colon (p < 0.001), bladder (p < 0.001), vagina (p = 0.04), and soft-tissue (p = 0.014) SPMs. Patients treated with brachytherapy had an increased risk of bladder SPM (p = 0.006). A positive bidirectional association with endometrial cancer was observed for colorectal cancer, with a negative bidirectional association for oropharyngeal and lung cancers. Conclusions: Genetic, environmental, and treatment-related factors influence SPM risk. Genetic factors may contribute to the increased risk of colorectal cancer. Smoking's negative effect on endometrial cancer risk factors might explain the decreased risk of lung and oropharyngeal cancer. Patients treated with radiotherapy likely have a small but significantly increased risk of bladder, vagina, colon, and soft-tissue SPM.« less

A new methodology to derive settleable particulate matter guidelines to assist policy-makers on reducing public nuisance

NASA Astrophysics Data System (ADS)

Machado, Milena; Santos, Jane Meri; Reisen, Valdério Anselmo; Reis, Neyval Costa; Mavroidis, Ilias; Lima, Ana T.

2018-06-01

Air quality standards for settleable particulate matter (SPM) are found in many countries around the world. As well known, annoyance caused by SPM can be considered a community problem even if only a small proportion of the population is bothered at rather infrequent occasions. Many authors have shown that SPM cause soiling in residential and urban environments and degradation of materials (eg, objects and surface painting) that can impair the use and enjoyment of property and alter the normal activities of society. In this context, this paper has as main contribution to propose a guidance to establish air quality standards for annoyance caused by SPM in metropolitan industrial areas. To attain this objective, a new methodology is proposed which is based on the nonlinear correlation between the perceived annoyance (qualitative variable) and particles deposition rate (quantitative variable). Since the response variable is binary (annoyed and not annoyed), the logistic regression model is used to estimate the probability of people being annoyed at different levels of particles deposition rate and to compute the odds ratio function which gives, under a specific level of particles deposition rate, the estimated expected value of the population perceived annoyance. The proposed methodology is verified in a data set measured in the metropolitan area of Great Vitória, Espirito Santo, Brazil. As a general conclusion, the estimated probability function of perceived annoyance as a function of SPM has shown that 17% of inhabitants report annoyance to very low particles deposition levels of 5 g/(m2•30 days). In addition, for an increasing of 1 g/(m2•30 days) of SPM, the smallest estimated odds ratio of perceived annoyance by a factor of 1.5, implying that the probability of occurrence is almost 2 times as large as the probability of no occurrence of annoyance.

Effect of dietary utilisation of sugarcane press mud on production performance of Muzaffarnagari lambs.

PubMed

Kumar, Ranjan; Saha, S K; Kumar, Dinesh; Mahesh, M S; Malapure, C D

2017-10-01

Sugarcane press mud (SPM) is one of the potential agro-industrial by-products available in India and research exploring its utilisation in small ruminant nutrition is scanty. In this direction, the present study evaluated the feasibility of dietary incorporation of SPM at different levels in a feeding trial lasting 180 days. A total of 21 Muzaffarnagari ram lambs were randomly distributed into three groups of seven each based on comparable body weight (11.70 ± 0.29 kg) and age (3-5 months) following a completely randomised design. The three dietary treatments were (1) SP 0 (control), concentrate mixture without SPM; (2) SP 10 , concentrate mixture comprising 10% SPM and (3) SP 20 , concentrate mixture comprising 20% SPM on air-dry basis. The experimental lambs were offered weighed quantity of designated isonitrogenous (crude protein = 20.6%) and isoenergetic (metabolisable energy = 12.1 MJ/kg) concentrate mixture (coarse mash) and along with ad libitum wheat straw (threshed to 1-2-cm length) and a 9-day metabolism trial was conducted. Results revealed no significant (P > 0.05) differences in intake and digestibility of nutrients, nitrogen balance, nutritive value of diets, average daily gain, as well as feed conversion ratio among three groups. The serum concentration of triiodothyronine and tetraiodothyronine did not differ due to treatments. Likewise, wool yield and its quality, measured in terms of fibre diameter, medullation percentage and staple length were also comparable irrespective of dietary variation. Furthermore, the cost of concentrate mixture (Rs/day) was lower (P ≤ 0.05) in SP 20 followed by SP 10 as compared to group SP 0 . These findings suggested that SPM could be safely fed up to 20% level in the concentrate mixture for lambs substituting expensive traditional feed ingredients without negatively inflicting the performance of growing lambs.

A population-based study of subsequent primary malignancies after endometrial cancer: genetic, environmental, and treatment-related associations.

PubMed

Brown, Aaron P; Neeley, E Shannon; Werner, Theresa; Soisson, Andrew Patrick; Burt, Randall W; Gaffney, David K

2010-09-01

To examine the risk of subsequent primary malignancies (SPMs) in women diagnosed with endometrial cancer. The National Cancer Institute's Survival, Epidemiology, and End Results database was used to determine the risk of SPM after endometrial cancer in 69,739 women diagnosed between 1973 and 2005. Standardized incidence ratios were calculated (observed/expected [O/E]) for SPM sites. Median follow-up was 11.2 years, representing 757,567 person-years of follow-up. The risk of SPM was significantly increased for small intestine (O/E = 1.48; 99% confidence interval [CI], 1.03-2.05), colon (O/E = 1.16; CI, 1.09-1.24), vagina (O/E = 2.71; CI, 1.86-3.8), and urinary bladder (O/E = 1.41; CI, 1.25-1.59) SPMs and decreased for oral cavity and pharynx (O/E = 0.75; CI, 0.6-0.93), lung and bronchus (O/E = 0.78; CI, 0.72-0.84), and esophagus (O/E = 0.58; CI, 0.37-0.86) SPMs. Patients receiving external-beam radiotherapy for endometrial cancer had an increased risk of colon (p < 0.001), bladder (p < 0.001), vagina (p = 0.04), and soft-tissue (p = 0.014) SPMs. Patients treated with brachytherapy had an increased risk of bladder SPM (p = 0.006). A positive bidirectional association with endometrial cancer was observed for colorectal cancer, with a negative bidirectional association for oropharyngeal and lung cancers. Genetic, environmental, and treatment-related factors influence SPM risk. Genetic factors may contribute to the increased risk of colorectal cancer. Smoking's negative effect on endometrial cancer risk factors might explain the decreased risk of lung and oropharyngeal cancer. Patients treated with radiotherapy likely have a small but significantly increased risk of bladder, vagina, colon, and soft-tissue SPM. Copyright (c) 2010 Elsevier Inc. All rights reserved.

Suspended particulate matter flocculation in a natural tidal wetland located in the San Francisco Estuary

NASA Astrophysics Data System (ADS)

Saraceno, J.; Bergamaschi, B. A.; Wright, S. A.; Boss, E.; Downing, B. D.; Fleck, J.; Ganju, N. K.

2011-12-01

Suspended mineral and algal particles together comprise suspended particulate matter (SPM). The SPM size distribution influences the quantity and color of light penetration and the adsorption and transport of contaminants such as pesticides and metals. It is widely known that interaction with wetlands alters the size distribution and quality of particles through local primary production, differential settling and particle aggregation, however, our understanding of how tidal wetland processes affect SPM quantity and size spectra has been hampered by the difficulty of directly observing these parameters at tidal time scales. To evaluate how SPM concentration and size varied over tidal time scales and to better understand the relationship between organic matter and sediment characteristics, simultaneous measurements of dissolved organic matter, SPM concentration and organic content as well as in situ surrogates of particle concentration (turbidity, particulate attenuation, volume concentration) and particle size (laser diffraction) were carried out with measurements of current velocity (acoustic Doppler velocity meter) in the main channel of Brown's Island located in the western San Joaquin/Sacramento River Delta, CA. The study period coincided with high estuary sediment levels following a significant precipitation runoff event. In the Brown Island wetland, particle concentration and size dynamics were tied to variations in water level and velocity. Turbidity and attenuation covaried with the volume concentration of particles smaller than 33 um, which on average represented greater than 50% of particle population by volume. On average, these SPM concentration surrogates were three times higher in flood water than in ebb water; consistent with a loss of fine particles on the island. Following the highest flood tide, the decrease in fine particles was coincident with an increase in the concentration of particles larger than 130 um; a finding consistent with particle flocculation. Additionally, the timing of flocculation was coincident with periods of elevated dissolved organic matter, suggesting organic matter played a role in the formation of large aggregates. Measurements of SPM organic content in ebb water revealed that SPM was enriched in organic matter by up to 50% following interaction with the wetland. Newly formed aggregates were carried out to the estuary with the ebb tide. These results indicate that the Browns Island wetland (and presumably other similar wetlands throughout the San Francisco Bay-Delta) plays an important role in estuarine biogeochemistry and particle cycling because flocculated particles have higher settling velocities and optical properties than their component particles and will behave differently. The implications of these findings are relevant to several tidal wetland management concerns such as the maintenance of marsh elevation, the cycling and transport of contaminants, and water clarity.

Protectin D1n-3 DPA and resolvin D5n-3 DPA are effectors of intestinal protection

PubMed Central

Gobbetti, Thomas; Dalli, Jesmond; Colas, Romain A.; Federici Canova, Donata; Aursnes, Marius; Bonnet, Delphine; Alric, Laurent; Vergnolle, Nathalie; Deraison, Celine; Hansen, Trond V.; Serhan, Charles N.

2017-01-01

The resolution of inflammation is an active process orchestrated by specialized proresolving lipid mediators (SPM) that limit the host response within the affected tissue; failure of effective resolution may lead to tissue injury. Because persistence of inflammatory signals is a main feature of chronic inflammatory conditions, including inflammatory bowel diseases (IBDs), herein we investigate expression and functions of SPM in intestinal inflammation. Targeted liquid chromatography-tandem mass spectrometry-based metabololipidomics was used to identify SPMs from n-3 polyunsaturated fatty acids in human IBD colon biopsies, quantifying a significant up-regulation of the resolvin and protectin pathway compared with normal gut tissue. Systemic treatment with protectin (PD)1n-3 DPA or resolvin (Rv)D5n-3 DPA protected against colitis and intestinal ischemia/reperfusion-induced inflammation in mice. Inhibition of 15-lipoxygenase activity reduced PD1n-3 DPA and augmented intestinal inflammation in experimental colitis. Intravital microscopy of mouse mesenteric venules demonstrated that PD1n-3 DPA and RvD5n-3 DPA decreased the extent of leukocyte adhesion and emigration following ischemia-reperfusion. These data were translated by assessing human neutrophil–endothelial interactions under flow: PD1n-3 DPA and RvD5n-3 DPA reduced cell adhesion onto TNF-α–activated human endothelial monolayers. In conclusion, we propose that innovative therapies based on n-3 DPA-derived mediators could be developed to enable antiinflammatory and tissue protective effects in inflammatory pathologies of the gut. PMID:28356517

Intermittent impact dynamics of a cantilever scanning a surface at high speed

NASA Astrophysics Data System (ADS)

Dey, S.; Kartik, V.

2018-03-01

In contact-mode scanning probe microscopy (SPM), the cantilever's dynamics are conventionally investigated by assuming the tip to be always in contact with the sample's surface. At high scanning speeds, however, the cantilever's inertia becomes dominant and the tip can therefore completely detach from the surface and start impacting upon it. Experiments at the macro-scale cannot emulate the complex micro-scale dynamics, as the system exhibits negligible effects due to meniscus forces and the surrounding medium's squeeze film damping; however, they can provide qualitative insight into the cantilever's dynamics at high frequencies, corresponding to those likely to be excited during video-rate SPM imaging. This paper investigates such intermittent impact dynamics for an upscaled cantilever, analytically, numerically, and experimentally. In contact-mode scanning, a critical scan speed exists beyond which the cantilever's tip loses contact with the sample's surface; a closed-form expression for this contact loss frequency is derived. At high scan speeds, impacts cause the cantilever to switch between different contact regimes: in-, off-, and grazing-contact; within each regime, the system's modal configuration is different. Experimentally-obtained Poincare maps indicate quasi-periodic behaviour at frequencies for which the response is repetitive, as is also predicted by the model. Intermittent impacts excite the sub- and super-harmonics of the excitation frequency, which are related to the natural frequencies of different system configurations based on the "effective" tip-end boundary conditions. The cantilever's response exhibits several phenomena, such as modal transition, beating, grazing, and possible chaotic behaviour, depending upon the relation between the excitation harmonics and the natural frequencies.

Accurate Assessment of the Oxygen Reduction Electrocatalytic Activity of Mn/Polypyrrole Nanocomposites Based on Rotating Disk Electrode Measurements, Complemented with Multitechnique Structural Characterizations

PubMed Central

Sánchez, Carolina Ramírez; Taurino, Antonietta; Bozzini, Benedetto

2016-01-01

This paper reports on the quantitative assessment of the oxygen reduction reaction (ORR) electrocatalytic activity of electrodeposited Mn/polypyrrole (PPy) nanocomposites for alkaline aqueous solutions, based on the Rotating Disk Electrode (RDE) method and accompanied by structural characterizations relevant to the establishment of structure-function relationships. The characterization of Mn/PPy films is addressed to the following: (i) morphology, as assessed by Field-Emission Scanning Electron Microscopy (FE-SEM) and Atomic Force Microscope (AFM); (ii) local electrical conductivity, as measured by Scanning Probe Microscopy (SPM); and (iii) molecular structure, accessed by Raman Spectroscopy; these data provide the background against which the electrocatalytic activity can be rationalised. For comparison, the properties of Mn/PPy are gauged against those of graphite, PPy, and polycrystalline-Pt (poly-Pt). Due to the literature lack of accepted protocols for precise catalytic activity measurement at poly-Pt electrode in alkaline solution using the RDE methodology, we have also worked on the obtainment of an intralaboratory benchmark by evidencing some of the time-consuming parameters which drastically affect the reliability and repeatability of the measurement. PMID:28042491

Digitally controlled analog proportional-integral-derivative (PID) controller for high-speed scanning probe microscopy

NASA Astrophysics Data System (ADS)

Dukic, Maja; Todorov, Vencislav; Andany, Santiago; Nievergelt, Adrian P.; Yang, Chen; Hosseini, Nahid; Fantner, Georg E.

2017-12-01

Nearly all scanning probe microscopes (SPMs) contain a feedback controller, which is used to move the scanner in the direction of the z-axis in order to maintain a constant setpoint based on the tip-sample interaction. The most frequently used feedback controller in SPMs is the proportional-integral (PI) controller. The bandwidth of the PI controller presents one of the speed limiting factors in high-speed SPMs, where higher bandwidths enable faster scanning speeds and higher imaging resolution. Most SPM systems use digital signal processor-based PI feedback controllers, which require analog-to-digital and digital-to-analog converters. These converters introduce additional feedback delays which limit the achievable imaging speed and resolution. In this paper, we present a digitally controlled analog proportional-integral-derivative (PID) controller. The controller implementation allows tunability of the PID gains over a large amplification and frequency range, while also providing precise control of the system and reproducibility of the gain parameters. By using the analog PID controller, we were able to perform successful atomic force microscopy imaging of a standard silicon calibration grating at line rates up to several kHz.

Digitally controlled analog proportional-integral-derivative (PID) controller for high-speed scanning probe microscopy.

PubMed

Dukic, Maja; Todorov, Vencislav; Andany, Santiago; Nievergelt, Adrian P; Yang, Chen; Hosseini, Nahid; Fantner, Georg E

2017-12-01

Nearly all scanning probe microscopes (SPMs) contain a feedback controller, which is used to move the scanner in the direction of the z-axis in order to maintain a constant setpoint based on the tip-sample interaction. The most frequently used feedback controller in SPMs is the proportional-integral (PI) controller. The bandwidth of the PI controller presents one of the speed limiting factors in high-speed SPMs, where higher bandwidths enable faster scanning speeds and higher imaging resolution. Most SPM systems use digital signal processor-based PI feedback controllers, which require analog-to-digital and digital-to-analog converters. These converters introduce additional feedback delays which limit the achievable imaging speed and resolution. In this paper, we present a digitally controlled analog proportional-integral-derivative (PID) controller. The controller implementation allows tunability of the PID gains over a large amplification and frequency range, while also providing precise control of the system and reproducibility of the gain parameters. By using the analog PID controller, we were able to perform successful atomic force microscopy imaging of a standard silicon calibration grating at line rates up to several kHz.

Toward quantitative electrochemical measurements on the nanoscale by scanning probe microscopy: environmental and current spreading effects.

PubMed

Arruda, Thomas M; Kumar, Amit; Jesse, Stephen; Veith, Gabriel M; Tselev, Alexander; Baddorf, Arthur P; Balke, Nina; Kalinin, Sergei V

2013-09-24

The application of electric bias across tip-surface junctions in scanning probe microscopy can readily induce surface and bulk electrochemical processes that can be further detected though changes in surface topography, Faradaic or conductive currents, or electromechanical strain responses. However, the basic factors controlling tip-induced electrochemical processes, including the relationship between applied tip bias and the thermodynamics of local processes, remains largely unexplored. Using the model Li-ion reduction reaction on the surface in Li-ion conducting glass ceramic, we explore the factors controlling Li-metal formation and find surprisingly strong effects of atmosphere and back electrode composition on the process. We find that reaction processes are highly dependent on the nature of the counter electrode and environmental conditions. Using a nondepleting Li counter electrode, Li particles could grow significantly larger and faster than a depleting counter electrode. Significant Li ion depletion leads to the inability for further Li reduction. Time studies suggest that Li diffusion replenishes the vacant sites after ∼12 h. These studies suggest the feasibility of SPM-based quantitative electrochemical studies under proper environmental controls, extending the concepts of ultramicroelectrodes to the single-digit nanometer scale.

Optimal geometry for a quartz multipurpose SPM sensor.

PubMed

Stirling, Julian

2013-01-01

We propose a geometry for a piezoelectric SPM sensor that can be used for combined AFM/LFM/STM. The sensor utilises symmetry to provide a lateral mode without the need to excite torsional modes. The symmetry allows normal and lateral motion to be completely isolated, even when introducing large tips to tune the dynamic properties to optimal values.

Polyamines and cellular metabolism in plants: Transgenic approaches reveal different responses to diamine putrescine versus higher polyamines spermidine and spermine

USDA-ARS?s Scientific Manuscript database

Distribution of biogenic amines – the diamine putrescine (Put), triamine spermidine (Spd), and tetraamine spermine (Spm) - differs between species with Put and Spd being particularly abundant and Spm the least abundant in plant cells. These amines are important for cell viability and their intracel...

Assessment of particulate matter variation during 2011-2015 over a tropical station Agra, India

NASA Astrophysics Data System (ADS)

Gogikar, Priyanjali; Tyagi, Bhishma

2016-12-01

Air quality over Agra is deteriorating and causing a serious threat to people residing in the city as well as to World heritage site- Tajmahal. In the present study, daily average concentrations of Suspended Particulate Matter (SPM) and Respirable Suspended Particulate Matter (RSPM) were analysed over a period of 2011-2015 at four stations in Agra city, namely: Taj, Itmad-Ud-Daula, Rambagh and Nunhai. The concentrations are above threshold values when compared to specify standards for a healthy environment (by India, US, WHO, EU and China - Class I and Class II) for all the seasons except monsoon and the values are highest in the month of November and lowest in the month of August and September. Variation of RSPM and SPM were found to be positively correlated with each other with values of 0.76 (Taj), 0.72 (Itmad-Ud-Daula), 0.69 (Rambagh), 0.77 (Nunhai). The study illustrates that the levels of SPM and RSPM are not showing any decreasing trend over Agra even after closing of industries and taking other precautions inside the city by Government of India. The study clearly identifies that local control of pollution sources are not enough and pollution is being transported from nearby regions to keep the daily pollution value higher than threshold. Source regions of transported pollutants over Agra have been analysed by using Weighted Potential Source Contribution Function (WPSCF) for both SPM and RSPM. Wavelet analysis of monthly averaged values of RSPM and SPM data sets has shown the existence of semi-annual and annual periodicity over the study region.

Amine oxidase-based biosensors for spermine and spermidine determination.

PubMed

Boffi, Alberto; Favero, Gabriele; Federico, Rodolfo; Macone, Alberto; Antiochia, Riccarda; Tortolini, Cristina; Sanzó, Gabriella; Mazzei, Franco

2015-02-01

The present work describes the development and optimization of electrochemical biosensors for specific determination of the biogenic polyamine spermine (Spm) and spermidine (Spmd) whose assessment represents a novel important analytical tool in food analysis and human diagnostics. These biosensors have been prepared using novel engineered enzymes: polyamine oxidase (PAO) endowed with selectivity towards Spm and Spmd and spermine oxidase (SMO) characterized by strict specificity towards Spm. The current design entails biosensors in which the enzymes were entrapped in poly(vinyl alcohol) bearing styrylpyridinium groups (PVA-SbQ), a photocrosslinkable gel, onto an electrode surface. Screen-printed electrodes (SPEs) were used as electrochemical transducers for enzymatically produced hydrogen peroxide, operating at different potential vs Ag/AgCl according to the material of the working electrode (WE): +700 mV for graphite (GP) or -100 mV for Prussian blue (PB)-modified SPE, respectively. Biosensor performances were evaluated by means of flow injection amperometric (FIA) measurements. The modified electrodes showed good sensitivity, long-term stability and reproducibility. Under optimal conditions, the PAO biosensor showed a linear range 0.003-0.3 mM for Spm and 0.01-0.4 mM for Spmd, while with the SMO biosensor, a linear range of 0.004-0.5 mM for Spm has been obtained. The main kinetic parameters apparent Michaelis constant (K M), turnover number (K cat) and steady-state current (I max) were determined. The proposed device was then applied to the determination of biogenic amines in blood samples. The results obtained were in good agreement with those obtained with the GC-MS reference method.

Polyamines contribute to salinity tolerance in the symbiosis Medicago truncatula-Sinorhizobium meliloti by preventing oxidative damage.

PubMed

López-Gómez, Miguel; Hidalgo-Castellanos, Javier; Muñoz-Sánchez, J Rubén; Marín-Peña, Agustín J; Lluch, Carmen; Herrera-Cervera, José A

2017-07-01

Polyamines (PAs) such as spermidine (Spd) and spermine (Spm) are small ubiquitous polycationic compounds that contribute to plant adaptation to salt stress. The positive effect of PAs has been associated to a cross-talk with other anti-stress hormones such as brassinosteroids (BRs). In this work we have studied the effects of exogenous Spd and Spm pre-treatments in the response to salt stress of the symbiotic interaction between Medicago truncatula and Sinorhizobium meliloti by analyzing parameters related to nitrogen fixation, oxidative damage and cross-talk with BRs in the response to salinity. Exogenous PAs treatments incremented the foliar and nodular Spd and Spm content which correlated with an increment of the nodule biomass and nitrogenase activity. Exogenous Spm treatment partially prevented proline accumulation which suggests that this polyamine could replace the role of this amino acid in the salt stress response. Additionally, Spd and Spm pre-treatments reduced the levels of H 2 O 2 and lipid peroxidation under salt stress. PAs induced the expression of genes involved in BRs biosynthesis which support a cross-talk between PAs and BRs in the salt stress response of M. truncatula-S. meliloti symbiosis. In conclusion, exogenous PAs improved the response to salinity of the M. truncatula-S. meliloti symbiosis by reducing the oxidative damage induced under salt stress conditions. In addition, in this work we provide evidences of the cross-talk between PAs and BRs in the adaptive responses to salinity. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Child Poverty: Definition and Measurement.

PubMed

Short, Kathleen S

2016-04-01

This article provides a discussion of what we mean when we refer to 'child poverty.' Many images come to mind when we discuss child poverty, but when we try to measure and quantify the extent of child poverty, we often use a very narrow concept. In this article a variety of poverty measures that are used in the United States are described and some of the differences between those measures are illustrated. In this article 3 measures are explored in detail: a relative measure of poverty that is used more often in an international context, the official US poverty measure, and a new supplemental poverty measure (SPM). The new measure differs from the other 2 because it takes into account noncash benefits that are provided to poor families. These include nutrition assistance such as food stamps, subsidized housing, and home energy assistance. The SPM also takes account of necessary expenses that families face, such as taxes and expenses related to work and health care. Comparing estimates for 2012, the SPM showed lower poverty rates for children than the other 2 measures. Because noncash benefits help those in extreme poverty, there were also lower percentages of children in extreme poverty with resources below half the SPM threshold. These results suggest that 2 important measures of poverty, the relative measure used in international comparisons, and the official poverty measure, are not able to gauge the effect of government programs on the alleviation of poverty, and the SPM illustrates that noncash benefits do help families meet their basic needs. Published by Elsevier Inc.

A simple method of equine limb force vector analysis and its potential applications

PubMed Central

Robinson, Mark A.; Clayton, Hilary M.

2018-01-01

Background Ground reaction forces (GRF) measured during equine gait analysis are typically evaluated by analyzing discrete values obtained from continuous force-time data for the vertical, longitudinal and transverse GRF components. This paper describes a simple, temporo-spatial method of displaying and analyzing sagittal plane GRF vectors. In addition, the application of statistical parametric mapping (SPM) is introduced to analyse differences between contra-lateral fore and hindlimb force-time curves throughout the stance phase. The overall aim of the study was to demonstrate alternative methods of evaluating functional (a)symmetry within horses. Methods GRF and kinematic data were collected from 10 horses trotting over a series of four force plates (120 Hz). The kinematic data were used to determine clean hoof contacts. The stance phase of each hoof was determined using a 50 N threshold. Vertical and longitudinal GRF for each stance phase were plotted both as force-time curves and as force vector diagrams in which vectors originating at the centre of pressure on the force plate were drawn at intervals of 8.3 ms for the duration of stance. Visual evaluation was facilitated by overlay of the vector diagrams for different limbs. Summary vectors representing the magnitude (VecMag) and direction (VecAng) of the mean force over the entire stance phase were superimposed on the force vector diagram. Typical measurements extracted from the force-time curves (peak forces, impulses) were compared with VecMag and VecAng using partial correlation (controlling for speed). Paired samples t-tests (left v. right diagonal pair comparison and high v. low vertical force diagonal pair comparison) were performed on discrete and vector variables using traditional methods and Hotelling’s T2 tests on normalized stance phase data using SPM. Results Evidence from traditional statistical tests suggested that VecMag is more influenced by the vertical force and impulse, whereas VecAng is more influenced by the longitudinal force and impulse. When used to evaluate mean data from the group of ten sound horses, SPM did not identify differences between the left and right contralateral limb pairs or between limb pairs classified according to directional asymmetry. When evaluating a single horse, three periods were identified during which differences in the forces between the left and right forelimbs exceeded the critical threshold (p < .01). Discussion Traditional statistical analysis of 2D GRF peak values, summary vector variables and visual evaluation of force vector diagrams gave harmonious results and both methods identified the same inter-limb asymmetries. As alpha was more tightly controlled using SPM, significance was only found in the individual horse although T2 plots followed the same trends as discrete analysis for the group. Conclusions The techniques of force vector analysis and SPM hold promise for investigations of sidedness and asymmetry in horses. PMID:29492341

The Shortened Raven Standard Progressive Matrices: Item Response Theory-Based Psychometric Analyses and Normative Data

ERIC Educational Resources Information Center

Van der Elst, Wim; Ouwehand, Carolijn; van Rijn, Peter; Lee, Nikki; Van Boxtel, Martin; Jolles, Jelle

2013-01-01

The purpose of the present study was to evaluate the psychometric properties of a shortened version of the Raven Standard Progressive Matrices (SPM) under an item response theory framework (the one- and two-parameter logistic models). The shortened Raven SPM was administered to N = 453 cognitively healthy adults aged between 24 and 83 years. The…

Evaluating Treatment and Generalization Patterns of Two Theoretically Motivated Sentence Comprehension Therapies.

PubMed

Des Roches, Carrie A; Vallila-Rohter, Sofia; Villard, Sarah; Tripodis, Yorghos; Caplan, David; Kiran, Swathi

2016-12-01

The current study examined treatment outcomes and generalization patterns following 2 sentence comprehension therapies: object manipulation (OM) and sentence-to-picture matching (SPM). Findings were interpreted within the framework of specific deficit and resource reduction accounts, which were extended in order to examine the nature of generalization following treatment of sentence comprehension deficits in aphasia. Forty-eight individuals with aphasia were enrolled in 1 of 8 potential treatment assignments that varied by task (OM, SPM), complexity of trained sentences (complex, simple), and syntactic movement (noun phrase, wh-movement). Comprehension of trained and untrained sentences was probed before and after treatment using stimuli that differed from the treatment stimuli. Linear mixed-model analyses demonstrated that, although both OM and SPM treatments were effective, OM resulted in greater improvement than SPM. Analyses of covariance revealed main effects of complexity in generalization; generalization from complex to simple linguistically related sentences was observed both across task and across movement. Results are consistent with the complexity account of treatment efficacy, as generalization effects were consistently observed from complex to simpler structures. Furthermore, results provide support for resource reduction accounts that suggest that generalization can extend across linguistic boundaries, such as across movement type.

Exact modelling of the optical bistability in ferroelectics via two-wave mixing: A system with full nonlinearity

NASA Astrophysics Data System (ADS)

Khushaini, Muhammad Asif A.; Ibrahim, Abdel-Baset M. A.; Choudhury, P. K.

2018-05-01

In this paper, we provide a complete mathematical model of the phenomenon of optical bistability (OB) resulting from the degenerate two-wave mixing (TWM) process of laser beams interacting with a single nonlinear layer of ferroelectric material. Starting with the electromagnetic wave equation for optical wave propagating in nonlinear media, a nonlinear coupled wave (CW) system with both self-phase modulation (SPM) and cross-phase modulation (XPM) sources of nonlinearity are derived. The complete CW system with full nonlinearity is solved numerically and a comparison between both the cases of with and without SPM at various combinations of design parameters is given. Furthermore, to provide a reliable theoretical model for the OB via TWM process, the results obtained theoretically are compared with the available experimental data. We found that the nonlinear system without SPM fails to predict the bistable response at lower combinations of the input parameters. However, at relatively higher values, the solution without SPM shows a reduction in the switching contrast and period in the OB response. A comparison with the experimental results shows better agreement with the system with full nonlinearity.

Potential implications of mine dusts on human health: A case study of Mukula Mine, Limpopo Province, South Africa

PubMed Central

Momoh, Abuh; E. Mhlongo, Sphiwe; Abiodun, Olukoga; Muzerengi, Confidence; Mudanalwo, Matamela

2013-01-01

Objective: The purpose of this study was to estimate the levels of Suspended Particulate Matter (SPM) in ambient air within Mukula mine and the potential risks to mineworkers and inhabitants of the adjoining Mukula community’s health. Methods : An SPM was used to measure the levels of particulate matter (PM10) in and around the mining site. One-way Analysis of Variance (ANOVA) was used to determine significance level of PM10 in ambient air. Results: Suspended particulate matter in the air ranged from 60.25 to 1820.45 µg/m3. The lowest value of SPM was more than four times the required World Health Organisation’s allowable level in ambient air, which the mine workers and locals would be inhaling. Conclusion: Continuous inhalation of mine dusts by mine workers and locals could result in pulmonary fibrosis, silicosis and lung cancer. The findings from this study support the need to have in place the necessary control measures that will drastically reduce SPM in the air. Such measure includes wet drilling and blasting, sprinkling of water on the mine roads and planting of vegetation around the mines and neighbouring communities. PMID:24550971

Novel n-3 Immunoresolvents: Structures and Actions

PubMed Central

Dalli, Jesmond; Colas, Romain A.; Serhan, Charles N.

2013-01-01

Resolution of inflammation is now held to be an active process where autacoids promote homeostasis. Using functional-metabololipidomics and in vivo systems, herein we report that endogenous n-3 docosapentaenoic (DPA) acid is converted during inflammation-resolution in mice and by human leukocytes to novel n-3 products congenerous to D-series resolvins (Rv), protectins (PD) and maresins (MaR), termed specialized pro-resolving mediators (SPM). The new n-3 DPA structures include 7,8,17-trihydroxy-9,11,13,15E,19Z-docosapentaenoic acid (RvD1n-3 DPA), 7,14-dihydroxy-8,10,12,16Z,19Z-docosapentaenoic acid (MaR1n-3 DPA) and related bioactive products. Each n-3 DPA-SPM displayed protective actions from second organ injury and reduced systemic inflammation in ischemia-reperfusion. The n-3 DPA-SPM, including RvD1n-3 DPA and MaR1n-3 DPA, each exerted potent leukocyte directed actions in vivo. With human leukocytes each n-3 DPA-SPM reduced neutrophil chemotaxis, adhesion and enhanced macrophage phagocytosis. Together, these findings demonstrate that n-3 DPA is converted to novel immunoresolvents with actions comparable to resolvins and are likely produced in humans when n-3 DPA is elevated. PMID:23736886

A Real-Time Infrared Ultra-Spectral Signature Classification Method via Spatial Pyramid Matching

PubMed Central

Mei, Xiaoguang; Ma, Yong; Li, Chang; Fan, Fan; Huang, Jun; Ma, Jiayi

2015-01-01

The state-of-the-art ultra-spectral sensor technology brings new hope for high precision applications due to its high spectral resolution. However, it also comes with new challenges, such as the high data dimension and noise problems. In this paper, we propose a real-time method for infrared ultra-spectral signature classification via spatial pyramid matching (SPM), which includes two aspects. First, we introduce an infrared ultra-spectral signature similarity measure method via SPM, which is the foundation of the matching-based classification method. Second, we propose the classification method with reference spectral libraries, which utilizes the SPM-based similarity for the real-time infrared ultra-spectral signature classification with robustness performance. Specifically, instead of matching with each spectrum in the spectral library, our method is based on feature matching, which includes a feature library-generating phase. We calculate the SPM-based similarity between the feature of the spectrum and that of each spectrum of the reference feature library, then take the class index of the corresponding spectrum having the maximum similarity as the final result. Experimental comparisons on two publicly-available datasets demonstrate that the proposed method effectively improves the real-time classification performance and robustness to noise. PMID:26205263

Comparison of Total Solar Irradiance with NASA/NSO Spectromagnetograph Data in Solar Cycles 22 and 23

NASA Technical Reports Server (NTRS)

Jones, Harrison P.; Branston, Detrick D.; Jones, Patricia B.; Popescu, Miruna D.

2002-01-01

An earlier study compared NASA/NSO Spectromagnetograph (SPM) data with spacecraft measurements of total solar irradiance (TSI) variations over a 1.5 year period in the declining phase of solar cycle 22. This paper extends the analysis to an eight-year period which also spans the rising and early maximum phases of cycle 23. The conclusions of the earlier work appear to be robust: three factors (sunspots, strong unipolar regions, and strong mixed polarity regions) describe most of the variation in the SPM record, but only the first two are associated with TSI. Additionally, the residuals of a linear multiple regression of TSI against SPM observations over the entire eight-year period show an unexplained, increasing, linear time variation with a rate of about 0.05 W m(exp -2) per year. Separate regressions for the periods before and after 1996 January 01 show no unexplained trends but differ substantially in regression parameters. This behavior may reflect a solar source of TSI variations beyond sunspots and faculae but more plausibly results from uncompensated non-solar effects in one or both of the TSI and SPM data sets.

Potential implications of mine dusts on human health: A case study of Mukula Mine, Limpopo Province, South Africa.

PubMed

Momoh, Abuh; E Mhlongo, Sphiwe; Abiodun, Olukoga; Muzerengi, Confidence; Mudanalwo, Matamela

2013-11-01

Objective : The purpose of this study was to estimate the levels of Suspended Particulate Matter (SPM) in ambient air within Mukula mine and the potential risks to mineworkers and inhabitants of the adjoining Mukula community's health. Methods : An SPM was used to measure the levels of particulate matter (PM10) in and around the mining site. One-way Analysis of Variance (ANOVA) was used to determine significance level of PM10 in ambient air. Results : Suspended particulate matter in the air ranged from 60.25 to 1820.45 µg/m(3). The lowest value of SPM was more than four times the required World Health Organisation's allowable level in ambient air, which the mine workers and locals would be inhaling. Conclusion : Continuous inhalation of mine dusts by mine workers and locals could result in pulmonary fibrosis, silicosis and lung cancer. The findings from this study support the need to have in place the necessary control measures that will drastically reduce SPM in the air. Such measure includes wet drilling and blasting, sprinkling of water on the mine roads and planting of vegetation around the mines and neighbouring communities.

Cholesterol asymmetry in synaptic plasma membranes.

PubMed

Wood, W Gibson; Igbavboa, Urule; Müller, Walter E; Eckert, Gunter P

2011-03-01

Lipids are essential for the structural and functional integrity of membranes. Membrane lipids are not randomly distributed but are localized in different domains. A common characteristic of these membrane domains is their association with cholesterol. Lipid rafts and caveolae are examples of cholesterol enriched domains, which have attracted keen interest. However, two other important cholesterol domains are the exofacial and cytofacial leaflets of the plasma membrane. The two leaflets that make up the bilayer differ in their fluidity, electrical charge, lipid distribution, and active sites of certain proteins. The synaptic plasma membrane (SPM) cytofacial leaflet contains over 85% of the total SPM cholesterol as compared with the exofacial leaflet. This asymmetric distribution of cholesterol is not fixed or immobile but can be modified by different conditions in vivo: (i) chronic ethanol consumption; (ii) statins; (iii) aging; and (iv) apoE isoform. Several potential candidates have been proposed as mechanisms involved in regulation of SPM cholesterol asymmetry: apoE, low-density lipoprotein receptor, sterol carrier protein-2, fatty acid binding proteins, polyunsaturated fatty acids, P-glycoprotein and caveolin-1. This review examines cholesterol asymmetry in SPM, potential mechanisms of regulation and impact on membrane structure and function. © 2011 The Authors. Journal of Neurochemistry © 2011 International Society for Neurochemistry.

Construction and evaluation of quantitative small-animal PET probabilistic atlases for [¹⁸F]FDG and [¹⁸F]FECT functional mapping of the mouse brain.

PubMed

Casteels, Cindy; Vunckx, Kathleen; Aelvoet, Sarah-Ann; Baekelandt, Veerle; Bormans, Guy; Van Laere, Koen; Koole, Michel

2013-01-01

Automated voxel-based or pre-defined volume-of-interest (VOI) analysis of small-animal PET data in mice is necessary for optimal information usage as the number of available resolution elements is limited. We have mapped metabolic ([(18)F]FDG) and dopamine transporter ([(18)F]FECT) small-animal PET data onto a 3D Magnetic Resonance Microscopy (MRM) mouse brain template and aligned them in space to the Paxinos co-ordinate system. In this way, ligand-specific templates for sensitive analysis and accurate anatomical localization were created. Next, using a pre-defined VOI approach, test-retest and intersubject variability of various quantification methods were evaluated. Also, the feasibility of mouse brain statistical parametric mapping (SPM) was explored for [(18)F]FDG and [(18)F]FECT imaging of 6-hydroxydopamine-lesioned (6-OHDA) mice. Twenty-three adult C57BL6 mice were scanned with [(18)F]FDG and [(18)F]FECT. Registrations and affine spatial normalizations were performed using SPM8. [(18)F]FDG data were quantified using (1) an image-derived-input function obtained from the liver (cMRglc), using (2) standardized uptake values (SUVglc) corrected for blood glucose levels and by (3) normalizing counts to the whole-brain uptake. Parametric [(18)F]FECT binding images were constructed by reference to the cerebellum. Registration accuracy was determined using random simulated misalignments and vectorial mismatch determination. Registration accuracy was between 0.21-1.11 mm. Regional intersubject variabilities of cMRglc ranged from 15.4% to 19.2%, while test-retest values were between 5.0% and 13.0%. For [(18)F]FECT uptake in the caudate-putamen, these values were 13.0% and 10.3%, respectively. Regional values of cMRglc positively correlated to SUVglc measured within the 45-60 min time frame (spearman r = 0.71). Next, SPM analysis of 6-OHDA-lesioned mice showed hypometabolism in the bilateral caudate-putamen and cerebellum, and an unilateral striatal decrease in DAT availability. MRM-based small-animal PET templates facilitate accurate assessment and spatial localization of mouse brain function using VOI or voxel-based analysis. Regional intersubject- and test-retest variations indicate that for these targets accuracy comparable to humans can be achieved.

Review of advanced imaging techniques

PubMed Central

Chen, Yu; Liang, Chia-Pin; Liu, Yang; Fischer, Andrew H.; Parwani, Anil V.; Pantanowitz, Liron

2012-01-01

Pathology informatics encompasses digital imaging and related applications. Several specialized microscopy techniques have emerged which permit the acquisition of digital images (“optical biopsies”) at high resolution. Coupled with fiber-optic and micro-optic components, some of these imaging techniques (e.g., optical coherence tomography) are now integrated with a wide range of imaging devices such as endoscopes, laparoscopes, catheters, and needles that enable imaging inside the body. These advanced imaging modalities have exciting diagnostic potential and introduce new opportunities in pathology. Therefore, it is important that pathology informaticists understand these advanced imaging techniques and the impact they have on pathology. This paper reviews several recently developed microscopic techniques, including diffraction-limited methods (e.g., confocal microscopy, 2-photon microscopy, 4Pi microscopy, and spatially modulated illumination microscopy) and subdiffraction techniques (e.g., photoactivated localization microscopy, stochastic optical reconstruction microscopy, and stimulated emission depletion microscopy). This article serves as a primer for pathology informaticists, highlighting the fundamentals and applications of advanced optical imaging techniques. PMID:22754737

Separate Poles Mode for Large-Capacity HVDC System

NASA Astrophysics Data System (ADS)

Zhu, Lin; Gao, Qin

2017-05-01

This paper proposes a novel connection mode, separate poles mode (SPM), for large-capacity HVDC systems. The proposed mode focuses on the core issues of HVDC connection in interconnected power grids and principally aims at increasing effective electric distance between poles, which helps to mitigate the interaction problems between AC system and DC system. Receiving end of bipolar HVDC has been divided into different inverter stations under the mode, and thus significantly alleviates difficulties in power transmission and consumption of receiving-end AC grids. By investigating the changes of multi-feed short-circuit ratio (MISCR), finding that HVDC with SPM shows critical impacts upon itself and other HVDC systems with conventional connection mode, which demonstrates that SPM can make balance between MISCR increase and short-circuit current limit.

METABOLISM OF N-ALKYLATED SPERMINE ANALOGUES BY POLYAMINE AND SPERMINE OXIDASES

PubMed Central

Häkkinen, Merja R.; Hyvönen, Mervi T.; Auriola, Seppo; Casero, Robert A.; Vepsäläinen, Jouko; Khomutov, Alex R.; Alhonen, Leena; Keinänen, Tuomo A.

2010-01-01

SUMMARY N-alkylated polyamine analogues have potential as anticancer and antiparasitic drugs. However, their metabolism in the host has remained incompletely defined thus potentially limiting their utility. Here, we have studied the degradation of three different spermine analogues N,N′-bis-(3-ethylaminopropyl)butane-1,4-diamine (DESPM), N-(3-benzyl-aminopropyl)-N'-(3-ethylaminopropyl)butane-1,4-diamine (BnEtSPM) and N,N′-bis-(3-benzylaminopropyl)butane-1,4-diamine (DBSPM) and related mono-alkylated derivatives as substrates of recombinant human polyamine oxidase (APAO) and spermine oxidase (SMO). APAO and SMO metabolized DESPM to EtSPD (Km(APAO)=10μM, kcat(APAO)=1.1s−1 and Km(SMO)=28μM, kcat(SMO)=0.8s−1, respectively), metabolized BnEtSPM to EtSPD (Km(APAO)=0.9 μM, kcat(APAO)=1.1s−1 and Km(SMO)=51μM, kcat(SMO)=0.4s−1, respectively), and metabolized DBSPM to BnSPD (Km(APAO)=5.4μM, kcat(APAO)= 2.0s−1 and Km(SMO)=33μM, kcat(SMO)=0.3s−1, respectively). Interestingly, mono-alkylated spermine derivatives were metabolized by APAO and SMO to SPD (EtSPM Km(APAO)=16μM, kcat(APAO)=1.5s−1; Km(SMO)=25μM, kcat(SMO) =8.2s−1; BnSPM Km(APAO)=6.0μM, kcat(APAO)=2.8s−1; Km(SMO)=19μM, kcat(SMO)=0.8s−1, respectively). Surprisingly, E t S P D ( Km(APAO)=37μM, kcat(APAO)=0.1s−1; Km(SMO)=48μM, kcat(SMO)=0.05s−1) and BnSPD (Km(APAO)=2.5μM, kcat(APAO)=3.5s−1; Km(SMO)=60μM, kcat(SMO)=0.54s−1) were metabolized to SPD by both the oxidases. Furthermore, we studied the degradation of DESPM, BnEtSPM or DBSPM in the DU145 prostate carcinoma cell line. The same major metabolites EtSPD and/or BnSPD were detected both in the culture medium and intracellularly after 48 hours of culture. Moreover, EtSPM and BnSPM were detected from cell samples. Present data shows that inducible SMO parallel with APAO could play an important role in polyamine based drug action, i.e. degradation of parent drug and its metabolites, having significant impact on efficiency of these drugs, and hence for the development of novel N-alkylated polyamine analogues. PMID:20012116

Second Primary Malignant Neoplasms and Survival in Adolescent and Young Adult Cancer Survivors.

PubMed

Keegan, Theresa H M; Bleyer, Archie; Rosenberg, Aaron S; Li, Qian; Goldfarb, Melanie

2017-11-01

Although the increased incidence of second primary malignant neoplasms (SPMs) is a well-known late effect after cancer, few studies have compared survival after an SPM to survival of the same cancer occurring as first primary malignant neoplasm (PM) by age. To assess the survival impact of SPMs in adolescents and young adults (AYAs) (15-39 years) compared with that of pediatric (<15 years) and older adult (≥40 years) patients with the same SPMs. This was a population-based, retrospective cohort study of patients with cancer in 13 Surveillance, Epidemiology and End Results regions in the United States diagnosed from 1992 to 2008 and followed through 2013. Data analysis was performed between June 2016 and January 2017. Five-year relative survival was calculated overall and for each cancer occurring as a PM or SPM by age at diagnosis. The impact of SPM status on cancer-specific death was examined using multivariable Cox proportional hazards regression. A total of 15 954 pediatric, 125 750 AYAs, and 878 370 older adult patients diagnosed as having 14 cancers occurring as a PM or SPM were included. Overall, 5-year survival after an SPM was 33.1% lower for children, 20.2% lower for AYAs, and 8.3% lower for older adults compared with a PM at the same age. For the most common SPMs in AYAs, the absolute difference in 5-year survival was 42% lower for secondary non-Hodgkin lymphoma, 19% for secondary breast carcinoma, 15% for secondary thyroid carcinoma, and 13% for secondary soft-tissue sarcoma. Survival by SPM status was significantly worse in younger vs older patients for thyroid, Hodgkin lymphoma, non-Hodgkin lymphoma, acute myeloid leukemia, soft-tissue sarcoma, and central nervous system cancer. Adolescents and young adults with secondary Hodgkin lymphoma (hazard ratio [95% CI], 3.5 [1.7-7.1]); soft-tissue sarcoma (2.8 [2.1-3.9]); breast carcinoma (2.1 [1.8-2.4]); acute myeloid leukemia (1.9 [1.5-2.4]); and central nervous system cancer (1.8 [1.2-2.8]) experienced worse survival compared with AYAs with the same PMs. The adverse impact of SPMs on survival is substantial for AYAs and may partially explain the relative lack of survival improvement in AYAs compared with other age groups. The impact of a particular SPM diagnosis on survival may inform age-specific prevention, screening, treatment, and survivorship recommendations.

Zinc and copper behaviour at the soil-river interface: New insights by Zn and Cu isotopes in the organic-rich Rio Negro basin

NASA Astrophysics Data System (ADS)

Guinoiseau, Damien; Gélabert, Alexandre; Allard, Thierry; Louvat, Pascale; Moreira-Turcq, Patricia; Benedetti, Marc F.

2017-09-01

The complex behaviour of Zn and Cu at the soil-river interface was investigated in soil and riverine water samples from the Rio Negro basin, a secondary tributary of the Rio Amazonas, using their stable isotope compositions. This acidic and organic river drains two types of intensely weathered terrains: podzols in its upstream part, and lateritic soils downstream. Bulk soil particles, suspended particulate matter (SPM) as well as colloidal fractions were sampled across the whole basin during low and high water stages. In the basin, Zn and Cu are mostly exported from lateritic soils and transported by organic colloids where significant losses are observed in the downstream part of the river. The use of δ66Zn and δ65Cu measurements reveals distinct stories for these two metals in suspended sediments and colloids. In the colloids, the constant δ66Zncoll across the basin is induced by the same weak association mode between Zn and organic ligands, regardless of the origin of the water. By contrast, in SPM, the speciation of Zn and thus δ66ZnSPM differ according to the type of drained soils. Zn is associated with organic complexes in particles exported with water draining podzol whereas Zn2+ is incorporated in the structure of the remaining kaolinite clays in lateritic output. The stronger reactivity of Cu than Zn with organic ligands induces its complete complexation. Copper is controlled by refractory particulate organic matter (POM) and by reactive colloidal organic matter; the latter being enriched in 65Cu due to stronger binding interactions than in POM. While the Cu content remains constant in the upstream part of the Rio Negro, downstream, the decrease of SPM and colloidal Cu fluxes is associated with a constant δ65CuSPM and with an increase of δ65Cucoll at the Rio Negro outlet. Geochemical mass balance modelling, based on SPM, Cu and Zn fluxes in SPM and their associated isotopic signatures, confirms distinct host phases for Zn and Cu, and identifies the most probable places where losses of these two metals occur. In colloids, the observed Cu isotope fractionation (from 0.24 to 0.45‰) superimposed on the significant Cucoll loss is assumed to result from a new isotopic equilibrium in a low velocity and high productivity zone: Cu-rich colloids enriched in 63Cu aggregate and settle down, whereas the remaining heavy Cu is partially complexed on strong organic ligands secreted by phytoplankton, forming new Cu-colloids.

Molecular dynamics simulations of Li transport between cathode crystals

NASA Astrophysics Data System (ADS)

Garofalini, S. H.

The molecular dynamics (MD) computer simulation technique has been used to study the effect of an amorphous intergranular film (IGF) present in a polycrystalline cathode on Li transport. The solid electrolyte is a model lithium silicate glass while the cathode is a nanocrystalline vanadia with an amorphous V 2O 5 IGF separating the crystals. Thin (˜1 to a few nanometer thick) IGFs are known to be present in most polycrystalline oxide materials. However, the role of such a film on Li transport in oxide cathodes has not been addressed. Current scanning probe microscopy (SPM) studies have shown that the orientation of the layered nanocrystalline vanadia crystals near the cathode/solid electrolyte interface is not optimized for Li ion transport. While the precise structure of the material between the crystals has not been identified, initially it can be initially considered as likely to be a thin non-crystalline (amorphous) film. This is based on the ubiquitous presence of such a structure in other polycrystalline oxides. Also, and with more relevance to the materials used in thin film batteries, an amorphous film can be expected to form between nanocrystals that crystallized from an amorphous matrix, as would be the case in a deposited thin film cathode. Consistent with simulations of Li transport in amorphous vanadia, the current simulations show that Li ions diffuse more rapidly into the amorphous intergranular thin film than into the layered vanadia with the (0 0 1) planes parallel to the cathode/electrolyte interface.

Study on the interaction of graphene oxide‑silver nanocomposites with bovine serum albumin and the formation of nanoparticle-protein corona.

PubMed

Xu, Xiangyu; Mao, Xuyan; Wang, Yunfei; Li, Dandan; Du, Zhongyu; Wu, Weihua; Jiang, Liang; Yang, Jie; Li, Jianjun

2018-05-09

The interaction between graphene oxide-sliver nanocomposites (GO-AgNCPs) and bovine serum albumin (BSA) in aqueous buffer solution was investigated by using several spectroscopic and imaging techniques. The visible absorbance intensity of GO-AgNCPs increased with increasing concentrations of BSA, and a slight redshift of the surface plasmon resonance band (SPR) occurred due to the absorption of BSA on the surface of GO-AgNCPs. Fluorescence data revealed a static quenching process of BSA caused by GO-AgNCPs. Thermodynamic parameters of the absorption process, including adsorption equilibrium constants, changes in Gibbs free energy (ΔG), enthalpy (ΔH) and entropy (ΔS), were evaluated at different temperatures. Negative values of ΔG showed that this process was spontaneous and the BSA-GO-AgNCPs complex might form in aqueous solution. Negative values of ΔH and ΔS suggested that the binding was mainly an enthalpy-driven process, and van der Waals forces and hydrogen bonding were the major force in the formation of the nanoparticle-protein corona. Analysis of synchronous, three dimensional (3D) fluorescence and circular dichroism (CD) spectra demonstrated that the conformation of BSA was slightly altered in the presence of GO-AgNCPs. The protein corona formed on the surface of GO-AgNCPs was directly observed by scanning probe microscopy (SPM). Copyright © 2018 Elsevier B.V. All rights reserved.

How Well Can Young People with Asperger's Disorder Recognize Threat and Learn about Affect in Faces?: A Pilot Study

ERIC Educational Resources Information Center

Miyahara, Motohide; Ruffman, Ted; Fujita, Chikako; Tsujii, Masatsugu

2010-01-01

The abilities to identify threat and learn about affect in facial photographs were compared between a non-autistic university student group (NUS), a matched Asperger's group (MAS) on the Standard Progressive Matrices (SPM), and an unmatched Asperger's group (UAS) who scored lower on the SPM. Participants were given pairs of faces and asked which…

Polyamines and cellular metabolism in plants: transgenic approaches reveal different responses to diamine putrescine versus higher polyamines spermidine and spermine

Treesearch

Autar K. Mattoo; Subhash C. Minocha; Rakesh Minocha; Avtar K. Handa

2010-01-01

Distribution of biogenic amines--the diamine putrescine (Put), triamine spermidine (Spd), and tetraamine spermine (Spm)--differs between species with Put and Spd being particularly abundant and Spm the least abundant in plant cells. These amines are important for cell viability and their intracellular levels are tightly regulated, which have made it difficult to...

Ferroelectric Switching by the Grounded Scanning Probe Microscopy Tip

DOE PAGES

Ievlev, Anton V.; Morozovska, A. N.; Shur, Vladimir Ya.; ...

2015-06-19

The process of polarization reversal by the tip of scanning probe microscope was intensively studied for last two decades. Number of the abnormal switching phenomena was reported by the scientific groups worldwide. In particularly it was experimentally and theoretically shown that slow dynamics of the surface screening controls kinetics of the ferroelectric switching, backswitching and relaxation and presence of the charges carriers on the sample surface and in the sample bulk significantly change polarization reversal dynamics. Here we experimentally demonstrated practical possibility of the history dependent polarization reversal by the grounded SPM tip. This phenomenon was attributed to induction ofmore » the slowly dissipating charges into the surface of the grounded tip that enables polarization reversal under the action of the produced electric field. Analytical and numerical electrostatic calculations allow additional insight into nontrivial abnormal switching phenomena reported earlier.« less

Fabricate heterojunction diode by using the modified spray pyrolysis method to deposit nickel-lithium oxide on indium tin oxide substrate.

PubMed

Wu, Chia-Ching; Yang, Cheng-Fu

2013-06-12

P-type lithium-doped nickel oxide (p-LNiO) thin films were deposited on an n-type indium tin oxide (ITO) glass substrate using the modified spray pyrolysis method (SPM), to fabricate a transparent p-n heterojunction diode. The structural, optical, and electrical properties of the p-LNiO and ITO thin films and the p-LNiO/n-ITO heterojunction diode were characterized by field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), UV-visible spectroscopy, Hall effect measurement, and current-voltage (I-V) measurements. The nonlinear and rectifying I-V properties confirmed that a heterojunction diode characteristic was successfully formed in the p-LNiO/n-ITO (p-n) structure. The I-V characteristic was dominated by space-charge-limited current (SCLC), and the Anderson model demonstrated that band alignment existed in the p-LNiO/n-ITO heterojunction diode.

Carbon Nanotube based Nanotechnolgy

NASA Astrophysics Data System (ADS)

Meyyappan, M.

2000-10-01

Carbon nanotube(CNT) was discovered in the early 1990s and is an off-spring of C60(the fullerene or buckyball). CNT, depending on chirality and diameter, can be metallic or semiconductor and thus allows formation of metal-semiconductor and semiconductor-semiconductor junctions. CNT exhibits extraordinary electrical and mechanical properties and offers remarkable potential for revolutionary applications in electronics devices, computing and data storage technology, sensors, composites, storage of hydrogen or lithium for battery development, nanoelectromechanical systems(NEMS), and as tip in scanning probe microscopy(SPM) for imaging and nanolithography. Thus the CNT synthesis, characterization and applications touch upon all disciplines of science and engineering. A common growth method now is based on CVD though surface catalysis is key to synthesis, in contrast to many CVD applications common in microelectronics. A plasma based variation is gaining some attention. This talk will provide an overview of CNT properties, growth methods, applications, and research challenges and opportunities ahead.

Exploring Carbon Nanotubes for Nanoscale Devices

NASA Technical Reports Server (NTRS)

Han, Jie; Dai; Anantram; Jaffe; Saini, Subhash (Technical Monitor)

1998-01-01

Carbon nanotubes (CNTs) are shown to promise great opportunities in nanoelectronic devices and nanoelectromechanical systems (NEMS) because of their inherent nanoscale sizes, intrinsic electric conductivities, and seamless hexagonal network architectures. I present our collaborative work with Stanford on exploring CNTs for nanodevices in this talk. The electrical property measurements suggest that metallic tubes are quantum wires. Furthermore, two and three terminal CNT junctions have been observed experimentally. We have proposed and studied CNT-based molecular switches and logic devices for future digital electronics. We also have studied CNTs based NEMS inclusing gears, cantilevers, and scanning probe microscopy tips. We investigate both chemistry and physics based aspects of the CNT NEMS. Our results suggest that CNT have ideal stiffness, vibrational frequencies, Q-factors, geometry-dependent electric conductivities, and the highest chemical and mechanical stabilities for the NEMS. The use of CNT SPM tips for nanolithography is presented for demonstration of the advantages of the CNT NEMS.

Multi-temporal dynamics of suspended particulate matter in a macro-tidal river Plume (the Gironde) as observed by satellite data

NASA Astrophysics Data System (ADS)

Constantin, Sorin; Doxaran, David; Derkacheva, Anna; Novoa, Stéfani; Lavigne, Héloïse

2018-03-01

The Gironde River plume area is unique in terms of Suspended Particulate Matter (SPM) dynamics. Multiple factors contribute to the variations of SPM at multiple time scales, from river outputs to wind stress, currents and tidal cycles. The formation and evolution of the Maximum Turbidity Zone (MTZ) inside the estuary also plays a significant role. Thus, detailed analyses and monitoring of the region is important for better understanding the mechanisms governing the turbid plume dynamics, for proper future management and monitoring of SPM export from the estuary to the coastal ocean. In this study we use an unprecedented volume of satellite data to capture and better understand the dynamics of the river plume. We combine two types of satellite information in order to achieve these goals: data collected by the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Spinning Enhanced Visible and Infrared Imager (SEVIRI) sensors. The integrated information allows accounting for multiple time scales, i.e. from seasonal to diurnal cycles. We show and parameterize the overall effects of river discharge rates over the plume extension. Seasonal variations are also analyzed and an overall relationship between river discharge rates and plume magnitude is computed. For the first time, we clearly observe and explain the diurnal cycle of SPM dynamics in the river plume. Despite the limited capabilities of the SEVIRI sensor, geostationary data was successfully used to derive such information and results similar to in-situ datasets were obtained. The same patterns are observed, with significant increase in SPM plume during spring/ebb tide periods. Results from our study can be further used to refine sediment transport models and to gain a better perspective on the ecological implications of the sediment output in the continental shelf area.

Sparse SPM: Group Sparse-dictionary learning in SPM framework for resting-state functional connectivity MRI analysis.

PubMed

Lee, Young-Beom; Lee, Jeonghyeon; Tak, Sungho; Lee, Kangjoo; Na, Duk L; Seo, Sang Won; Jeong, Yong; Ye, Jong Chul

2016-01-15

Recent studies of functional connectivity MR imaging have revealed that the default-mode network activity is disrupted in diseases such as Alzheimer's disease (AD). However, there is not yet a consensus on the preferred method for resting-state analysis. Because the brain is reported to have complex interconnected networks according to graph theoretical analysis, the independency assumption, as in the popular independent component analysis (ICA) approach, often does not hold. Here, rather than using the independency assumption, we present a new statistical parameter mapping (SPM)-type analysis method based on a sparse graph model where temporal dynamics at each voxel position are described as a sparse combination of global brain dynamics. In particular, a new concept of a spatially adaptive design matrix has been proposed to represent local connectivity that shares the same temporal dynamics. If we further assume that local network structures within a group are similar, the estimation problem of global and local dynamics can be solved using sparse dictionary learning for the concatenated temporal data across subjects. Moreover, under the homoscedasticity variance assumption across subjects and groups that is often used in SPM analysis, the aforementioned individual and group analyses using sparse dictionary learning can be accurately modeled by a mixed-effect model, which also facilitates a standard SPM-type group-level inference using summary statistics. Using an extensive resting fMRI data set obtained from normal, mild cognitive impairment (MCI), and Alzheimer's disease patient groups, we demonstrated that the changes in the default mode network extracted by the proposed method are more closely correlated with the progression of Alzheimer's disease. Copyright © 2015 Elsevier Inc. All rights reserved.

Anti-ghrelin Spiegelmer inhibits exogenous ghrelin-induced increases in food intake, hoarding, and neural activation, but not food deprivation-induced increases

PubMed Central

Teubner, Brett J. W.

2013-01-01

Circulating concentrations of the stomach-derived “hunger-peptide” ghrelin increase in direct proportion to the time since the last meal. Exogenous ghrelin also increases food intake in rodents and humans, suggesting ghrelin may increase post-fast ingestive behaviors. Food intake after food deprivation is increased by laboratory rats and mice, but not by humans (despite dogma to the contrary) or by Siberian hamsters; instead, humans and Siberian hamsters increase food hoarding, suggesting the latter as a model of fasting-induced changes in human ingestive behavior. Exogenous ghrelin markedly increases food hoarding by ad libitum-fed Siberian hamsters similarly to that after food deprivation, indicating sufficiency. Here, we tested the necessity of ghrelin to increase food foraging, food hoarding, and food intake, and neural activation [c-Fos immunoreactivity (c-Fos-ir)] using anti-ghrelin Spiegelmer NOX-B11–2 (SPM), an l-oligonucleotide that specifically binds active ghrelin, inhibiting peptide-receptor interaction. SPM blocked exogenous ghrelin-induced increases in food hoarding the first 2 days after injection, and foraging and food intake at 1–2 h and 2–4 h, respectively, and inhibited hypothalamic c-Fos-ir. SPM given every 24 h across 48-h food deprivation inconsistently inhibited food hoarding after refeeding and c-Fos-ir, similarly to inabilities to do so in laboratory rats and mice. These results suggest that ghrelin may not be necessary for food deprivation-induced foraging and hoarding and neural activation. A possible compensatory response, however, may underlie these findings because SPM treatment led to marked increases in circulating ghrelin concentrations. Collectively, these results show that SPM can block exogenous ghrelin-induced ingestive behaviors, but the necessity of ghrelin for food deprivation-induced ingestive behaviors remains unclear. PMID:23804279

Co-pyrolysis of swine manure with agricultural plastic waste: laboratory-scale study.

PubMed

Ro, Kyoung S; Hunt, Patrick G; Jackson, Michael A; Compton, David L; Yates, Scott R; Cantrell, Keri; Chang, SeChin

2014-08-01

Manure-derived biochar is the solid product resulting from pyrolysis of animal manures. It has considerable potential both to improve soil quality with high levels of nutrients and to reduce contaminants in water and soil. However, the combustible gas produced from manure pyrolysis generally does not provide enough energy to sustain the pyrolysis process. Supplementing this process may be achieved with spent agricultural plastic films; these feedstocks have large amounts of available energy. Plastic films are often used in soil fumigation. They are usually disposed in landfills, which is wasteful, expensive, and environmentally unsustainable. The objective of this work was to investigate both the energetics of co-pyrolyzing swine solids with spent plastic mulch films (SPM) and the characteristics of its gas, liquid, and solid byproducts. The heating value of the product gas from co-pyrolysis was found to be much higher than that of natural gas; furthermore, the gas had no detectable toxic fumigants. Energetically, sustaining pyrolysis of the swine solids through the energy of the product gas could be achieved by co-pyrolyzing dewatered swine solids (25%m/m) with just 10% SPM. If more than 10% SPM is used, the co-pyrolysis would generate surplus energy which could be used for power generation. Biochars produced from co-pyrolyzing SPM and swine solid were similar to swine solid alone based on the surface area and the (1)H NMR spectra. The results of this study demonstrated the potential of using pyrolysis technology to manage two prominent agricultural waste streams (SPM and swine solids) while producing value-added biochar and a power source that could be used for local farm operations. Published by Elsevier Ltd.

Source apportionment of settleable particles in an impacted urban and industrialized region in Brazil.

PubMed

Santos, Jane Meri; Reis, Neyval Costa; Galvão, Elson Silva; Silveira, Alexsander; Goulart, Elisa Valentim; Lima, Ana Teresa

2017-09-01

Settleable particulate matter (SPM), especially coarser particles with diameters greater than 10 μm, has been found culprit of high deposition rates in cities affected by hinterland industrial activities. This is the case of Metropolitan Region of Vitoria (MRV), Espirito Santo, Brazil where industrial facilities are located within the urban sprawl and building constructions are intense. Frequent population complaints to the environmental protection agency (IEMA) throughout the years have triggered monitoring campaigns to determine SPM deposition rates and source apportionment. Eight different locations were monitored throughout the MRV, and SPM was quantified and chemically characterized. Sources profiles were defined either by using US EPA SPECIATE data or by experimental analysis. Atmospheric fallout in the MRV ranged between 2 and 20g/(m 2 30-day), with only one monitoring station ranging from 6-10 g/(m 2 30-day). EC, OC, Fe, Al, and Si were found the main constituents of dry deposition in the region. Source apportionment by the chemical mass balance (CMB) model determined that steel and iron ore pelletizing industries were the main contributor to one of the eight locations whereas resuspension, civil construction, and vehicular sources were also very important contributors to the other stations. Quarries and soil were also considered expressive SPM sources, but at the city periphery. CMB model could differentiate contributions from six industrial source groups: thermoelectric; iron ore, pellet, and pellet furnaces; coal coke and coke oven; sintering, blast furnace, and basic oxygen furnace; and soil, resuspension, and vehicles. However, the CMB model was unable to differentiate between iron ore and pellet stockpiles which are present in both steel and iron ore pelletizing industries. Further characterization of source and SPM might be necessary to aid local authorities in decision-making regarding these two industrial sources.

Nature, Origin and Transfers of SPM (Mineral, Organic, and Biological) in Hydrosystems : a New Methodological Approach by Morphogranulometry

NASA Astrophysics Data System (ADS)

Viennet, D.; Fournier, M.; Copard, Y.; Dupont, J. P.

2017-12-01

Source to sink is one of the main concepts in Earth Sciences for a better knowledge of hydrosystems dynamics. Regarding this issue, the present day challenge consists in the characterization by in-situ measurements of the nature and the origin of suspended particles matters (SPM). Few methods can fully cover such requirements and among them, the methodology using the form of particles deserves to be developed. Indeed, morphometry of particles is widely used in sedimentology to identify different sedimentary stocks, source-to-sink transport and sedimentation mechanisms. Currently, morphometry analyses are carried out by scanning electron microscope coupled to image analysis to measure various size and shape descriptors on particles like flatness, elongation, circularity, sphericity, bluntness, fractal dimension. However, complexity and time of analysis are the main limitations of this technique for a long-term monitoring of SPM transfers. Here we present an experimental morphometric approach using a morphogranulometer (a CCD camera coupled to a peristaltic pump). The camera takes pictures while the sample is circulating through a flow cell, leading to the analysis of numerous particles in a short time. The image analysis provides size and shape information discriminating various particles stocks according to their nature and origin by statistical analyses. Measurements were carried out on standard samples of particles commonly found in natural waters. The size and morphological distributions of the different mineral fractions (clay, sand, oxides etc), biologic (microalgae, pollen, etc) and organic (peat, coal, soil organic matter, etc) samples are statistically independent and can be discriminated on a 4D graph. Next step will be on field in situ measurements in a sink-spring network to understand the transfers of the particles stocks inside this simple karstic network. Such a development would be promising for the characterisation of natural hydrosystems.

Influence of group-delay ripple on timing jitter induced by SPM and IXPM in systems with dispersion compensated by CFBG

NASA Astrophysics Data System (ADS)

Qin, Xi; Cao, Jihong; Chen, Yong; Zhang, Feng; Jian, Shuisheng

2007-08-01

An analytical expression was proposed to analyze the influence of group-delay ripple (GDR) on timing jitter induced by self-phase modulation (SPM) and intra-channel cross-phase modulation (IXPM) in pseudo-linear transmission systems when dispersion was compensated by chirped fiber Bragg grating (CFBG). Effects of ripple amplitude, period, and phase on timing jitter were discussed by theoretical and numerical analysis in detail. The results show that the influence of GDR on timing jitter changes linearly with the amplitude of GDR and whether it decreases or increases the timing jitter relies on the ripple period and ripple phase. Timing jitter induced by SPM and IXPM could be suppressed totally by adjusting the relative phase between the center frequency of the pulse and the ripples.

Grid pattern of nanothick microgel network.

PubMed

Chen, Guoping; Kawazoe, Naoki; Fan, Yujiang; Ito, Yoshihiro; Tateishi, Tetsuya

2007-05-22

A novel grid pattern of two kinds of nanothick microgels was developed by alternate patterning using photolithography. At first, 100-microm-wide nanothick PAAm microgel stripes were grafted on a polystyrene surface by UV irradiation of the photoreactive azidobenzoyl-derivatized polyallylamine-coated surface through a photomask with 100-microm-wide stripes. Then, a second set of 100-microm-wide nanothick PAAc microgel stripes were grafted across the PAAm-grated polystyrene surface by UV irradiation of the photoreactive azidophenyl-derivatized poly(acrylic acid)-coated surface through a photomask placed perpendicularly to the first set of PAAm microgel stripes. The PAAc microgel stripe pattern was formed over the PAAm microgel stripe pattern. The cross angle of the two microgel stripes could be controlled by adjusting the position of the photomask when the second microgel pattern was prepared. Swelling and shrinking of the microgels were investigated by scanning probe microscopy (SPM) in an aqueous solution. SPM observation indicated that the thickness of the gel network was 100 to 500 nm. The regions containing PAAm, PAAc, and the PAAc-PAAm overlapping microgels showed different swelling and shrinking properties when the pH was changed. The PAAm microgel swelled at low pH and shrank at high pH whereas the PAAc microgel swelled at high pH and shrank at low pH. However, the PAAc-PAAm overlapping microgel did not change as significantly as did the two microgels, indicating that the swelling and shrinking of the two gels was partially offset. The pH-induced structural change was repeatedly reversible. The novel grid pattern of nanothick microgels will find applications in various fields such as smart actuators, artificial muscles, sensors, and drug delivery systems as well as in tissue engineering and so forth.

Schooling mediates brain reserve in Alzheimer's disease: findings of fluoro-deoxy-glucose-positron emission tomography.

PubMed

Perneczky, R; Drzezga, A; Diehl-Schmid, J; Schmid, G; Wohlschläger, A; Kars, S; Grimmer, T; Wagenpfeil, S; Monsch, A; Kurz, A

2006-09-01

Functional imaging studies report that higher education is associated with more severe pathology in patients with Alzheimer's disease, controlling for disease severity. Therefore, schooling seems to provide brain reserve against neurodegeneration. To provide further evidence for brain reserve in a large sample, using a sensitive technique for the indirect assessment of brain abnormality (18F-fluoro-deoxy-glucose-positron emission tomography (FDG-PET)), a comprehensive measure of global cognitive impairment to control for disease severity (total score of the Consortium to Establish a Registry for Alzheimer's Disease Neuropsychological Battery) and an approach unbiased by predefined regions of interest for the statistical analysis (statistical parametric mapping (SPM)). 93 patients with mild Alzheimer's disease and 16 healthy controls underwent 18F-FDG-PET imaging of the brain. A linear regression analysis with education as independent and glucose utilisation as dependent variables, adjusted for global cognitive status and demographic variables, was conducted in SPM2. The regression analysis showed a marked inverse association between years of schooling and glucose metabolism in the posterior temporo-occipital association cortex and the precuneus in the left hemisphere. In line with previous reports, the findings suggest that education is associated with brain reserve and that people with higher education can cope with brain damage for a longer time.

SPM of nonlinear surface plasmon waveguides

NASA Astrophysics Data System (ADS)

Li, Yuee; Zhang, Xiaoping

2008-10-01

Pulse propagation equation of nonlinear dispersion surface plasmon waveguide is educed strictly from wave equation. The nonlinear coefficient is defined and then used to assess and compare the nonlinear characteristic of three popular 1-D surface plasmon waveguides: the single metal-dielectric interface, the metal slab bounded by dielectric and the dielectric slab bounded by metal. SPM (self-phase modulation) of the typical surface plasmon waveguide is predicted and discussed.

Influence of cross-phase modulation in SPM-based nonlinear optical loop mirror

NASA Astrophysics Data System (ADS)

Pitois, Stéphane

2005-09-01

We study the role of cross-phase modulation (CPM) occurring between the two counter-propagating parts of a signal wave in a standard SPM-based nonlinear optical fiber loop mirror (NOLM). For pulse train with high duty-cycle, we experimentally observe the influence of cross-phase modulation on NOLM transmittivity. Finally, we propose a solution based on properly designed dispersion imbalanced NOLM to overcome undesirable CPM effects.

Spermine Regulates Pollen Tube Growth by Modulating Ca2+-Dependent Actin Organization and Cell Wall Structure

PubMed Central

Aloisi, Iris; Cai, Giampiero; Faleri, Claudia; Navazio, Lorella; Serafini-Fracassini, Donatella; Del Duca, Stefano

2017-01-01

Proper growth of the pollen tube depends on an elaborate mechanism that integrates several molecular and cytological sub-processes and ensures a cell shape adapted to the transport of gametes. This growth mechanism is controlled by several molecules among which cytoplasmic and apoplastic polyamines. Spermine (Spm) has been correlated with various physiological processes in pollen, including structuring of the cell wall and modulation of protein (mainly cytoskeletal) assembly. In this work, the effects of Spm on the growth of pear pollen tubes were analyzed. When exogenous Spm (100 μM) was supplied to germinating pollen, it temporarily blocked tube growth, followed by the induction of apical swelling. This reshaping of the pollen tube was maintained also after growth recovery, leading to a 30–40% increase of tube diameter. Apical swelling was also accompanied by a transient increase in cytosolic calcium concentration and alteration of pH values, which were the likely cause for major reorganization of actin filaments and cytoplasmic organelle movement. Morphological alterations of the apical and subapical region also involved changes in the deposition of pectin, cellulose, and callose in the cell wall. Thus, results point to the involvement of Spm in cell wall construction as well as cytoskeleton organization during pear pollen tube growth. PMID:29033970

Evaluating Treatment and Generalization Patterns of Two Theoretically Motivated Sentence Comprehension Therapies

PubMed Central

Des Roches, Carrie A.; Vallila-Rohter, Sofia; Villard, Sarah; Tripodis, Yorghos; Caplan, David

2016-01-01

Purpose The current study examined treatment outcomes and generalization patterns following 2 sentence comprehension therapies: object manipulation (OM) and sentence-to-picture matching (SPM). Findings were interpreted within the framework of specific deficit and resource reduction accounts, which were extended in order to examine the nature of generalization following treatment of sentence comprehension deficits in aphasia. Method Forty-eight individuals with aphasia were enrolled in 1 of 8 potential treatment assignments that varied by task (OM, SPM), complexity of trained sentences (complex, simple), and syntactic movement (noun phrase, wh-movement). Comprehension of trained and untrained sentences was probed before and after treatment using stimuli that differed from the treatment stimuli. Results Linear mixed-model analyses demonstrated that, although both OM and SPM treatments were effective, OM resulted in greater improvement than SPM. Analyses of covariance revealed main effects of complexity in generalization; generalization from complex to simple linguistically related sentences was observed both across task and across movement. Conclusions Results are consistent with the complexity account of treatment efficacy, as generalization effects were consistently observed from complex to simpler structures. Furthermore, results provide support for resource reduction accounts that suggest that generalization can extend across linguistic boundaries, such as across movement type. PMID:27997950

Study of Intermediate Age (~10-30 Myr) Open Clusters

NASA Astrophysics Data System (ADS)

Olguin, Lorenzo; Michel, Raul; Contreras, Maria; Hernandez, Jesus; Schuster, William; Chavarria-Kleinhenn, Carlos

2013-07-01

We present the study of a sample of intermediate age open clusters (age ~ 10-30 Myr) using optical (UBVRI) and infrared photometric data. Optical photometry was obtained as part of the San Pedro Martir Open Clusters Project (SPM-OCP, Schuster et al. 2007; Michel et al. 2013). Infrared photometry was retrieved from 2MASS public data archive and WISE database. Open clusters included in the SPM-OCP were selected from catalogues presented by Dias et al. (2002) and Froebrich, Scholz & Raftery (2007). One of the main goals of the SPM-OCP is to compile a self-consistent and homogeneous set of cluster fundamental parameters such as reddening, distance, age, and metallicity whenever possible. In this work, we have analyzed a set of 25 clusters from the SPM-OCP with estimated ages between 10 and 30 Myr. Derived fundamental parameters for each cluster in the sample as well as an example of typical color-color and color-magnitude diagrams are presented. Kinematic membership was established by using proper motion data taken from the literature. Based on infrared photometry, we have searched for candidate stars to posses a circumstellar disk within each clusters. For those selected candidates a follow-up spectroscpic study is being carried out. This work was partially supported by UNAM-PAPIIT grant IN-109311.

Assessment of air quality in and around a steel industry with direct reduction iron route.

PubMed

Jena, Pradip K; Behera, Dillip K; Mishra, C S K; Mohanty, Saswat K

2011-10-01

The coal based Direct Reduced Iron (DRI) route for secondary steel production is now a preferred choice in India. Steel making is invariably associated with emission of air pollutants into the environment. Air quality monitoring was carried out in Winter, Summer and Rainy seasons of 2008 in eight monitoring stations in the work zone and five stations in the residential zone of an Integrated Steel Industry located in Orissa state, India. Four air quality parameters i.e. SPM, RSPM, SO2 and NO2 were monitored. Mean SPM and RSPM values were found to be significantly high (p < 0.01) at stations nearer to source in both work zone and residential zone .The highest average SPM and RSPM values in the work zone recorded were 4869 microg/m3 and 1420 microg/m3 and in the residential zone 294 microg/m3 and 198 microg/m3 respectively. No significant difference in the SO2 and NO2 levels was observed between the work and residential zones. In general, the values of air pollutants were highest in Winter followed by Summer and Rainy season. SPM and RSPM values exceeded the National Air Quality Standards (NAAQS) in both the residential and work zones.

Photometric calibration of the COMBO-17 survey with the Softassign Procrustes Matching method

NASA Astrophysics Data System (ADS)

Sheikhbahaee, Z.; Nakajima, R.; Erben, T.; Schneider, P.; Hildebrandt, H.; Becker, A. C.

2017-11-01

Accurate photometric calibration of optical data is crucial for photometric redshift estimation. We present the Softassign Procrustes Matching (SPM) method to improve the colour calibration upon the commonly used Stellar Locus Regression (SLR) method for the COMBO-17 survey. Our colour calibration approach can be categorised as a point-set matching method, which is frequently used in medical imaging and pattern recognition. We attain a photometric redshift precision Δz/(1 + zs) of better than 2 per cent. Our method is based on aligning the stellar locus of the uncalibrated stars to that of a spectroscopic sample of the Sloan Digital Sky Survey standard stars. We achieve our goal by finding a correspondence matrix between the two point-sets and applying the matrix to estimate the appropriate translations in multidimensional colour space. The SPM method is able to find the translation between two point-sets, despite the existence of noise and incompleteness of the common structures in the sets, as long as there is a distinct structure in at least one of the colour-colour pairs. We demonstrate the precision of our colour calibration method with a mock catalogue. The SPM colour calibration code is publicly available at https://neuronphysics@bitbucket.org/neuronphysics/spm.git.

Templating Biomineralization: Surface Directed Protein Self-assembly and External Magnetic Field Stimulation of Osteoblasts

NASA Astrophysics Data System (ADS)

Ba, Xiaolan

Biomineralization is a wide-spread phenomenon in the biological systems, which is the process of mineral formation by organisms through interaction between its organic contents and the inorganic minerals. The process is essential in a broad spectrum of biological phenomena ranging from bone and tooth formation to pathological mineralization under hypoxic conditions or cancerous formations. In this thesis I studied biomineralization at the earliest stages in order to obtain a better understanding of the fundamental principals involved. This knowledge is essential if we want to engineer devices which will increase bone regeneration or prevent unwanted mineral deposits. Extracellular matrix (ECM) proteins play an essential role during biomineralization in bone and engineered tissues. In this dissertation, I present an approach to mimic the ECM in vitro to probe the interactions of these proteins with calcium phosphate mineral and with each other. Early stage of mineralization is investigated by mechanical properties of the protein fibers using Scanning Probe Microscopy (SPM) and Shear Modulation Force Microscopy (SMFM). The development of mineral crystals on the protein matrices is also characterized by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Grazing Incidence X-ray Diffraction (GIXRD). The results demonstrate complementary actions of the two ECM proteins to collect cations and template calcium phosphate mineral, respectively. Magnets have been clinically used as an "induction source" in various bone or orthodontic treatments. However, the mechanism and effects of magnetic fields remain unclear. In this dissertation, I also undertake the present investigation to study the effects of 150 mT static magnetic fields (SMF) on ECM development and cell biomineralization using MC3T3-E1 osteobalst-like cells. Early stage of biomineralization is characterized by SPM, SMFM and confocal laser scanning microscopy (CSLM). Late stage of biomineralization is investigated by SEM, GIXRD and energy dispersive X-ray spectroscopy (EDXS). Gene expression during the exposure of SMF is also studies by RT-PCR. The results indicated that exposure to SMF induces osteoblasts to produce larger quantities of HA, with higher degree of crystalline order. The controlling and understanding of protein on the surface is of great interest in biomedical application such as implant medicine, biosensor design, food processing, and chromatographic separations. The adsorbed protein onto the surface significantly determines the performance of biomaterials in a biological environment. Recent studies have suggested that the preservation of the native secondary structure of protein adsorbed is essential for biological application. In order to manipulate protein adsorption and design biocompatible materials, the mechanisms underlying protein-surface interactions, especially how surface properties of materials induce conformational changes of adsorbed proteins, needs to be well understood. Here we demonstrated that even though SPS is a necessary condition, it is not sufficient. We show that low substrate conductivity as well as proper salt concentration are also critical in sustained protein adsorption continuously. These factors allow one to pattern regions of different conducting properties and for the first time patterns physiologically relevant protein structures. Here we show that we can achieve patterned biomineralized regimes, both with plasma proteins in a simple and robust manner without additional functionalization or application of electrochemical gradients. Since the data indicate that the patterns just need to differ in electrical conductivity, rather than surface chemistry, we propose that the creation of transient image charges, due to incomplete charge screening, may be responsible for sustain the driving force for continual protein absorption.

Microscopy techniques in flavivirus research.

PubMed

Chong, Mun Keat; Chua, Anthony Jin Shun; Tan, Terence Tze Tong; Tan, Suat Hoon; Ng, Mah Lee

2014-04-01

The Flavivirus genus is composed of many medically important viruses that cause high morbidity and mortality, which include Dengue and West Nile viruses. Various molecular and biochemical techniques have been developed in the endeavour to study flaviviruses. However, microscopy techniques still have irreplaceable roles in the identification of novel virus pathogens and characterization of morphological changes in virus-infected cells. Fluorescence microscopy contributes greatly in understanding the fundamental viral protein localizations and virus-host protein interactions during infection. Electron microscopy remains the gold standard for visualizing ultra-structural features of virus particles and infected cells. New imaging techniques and combinatory applications are continuously being developed to push the limit of resolution and extract more quantitative data. Currently, correlative live cell imaging and high resolution three-dimensional imaging have already been achieved through the tandem use of optical and electron microscopy in analyzing biological specimens. Microscopy techniques are also used to measure protein binding affinities and determine the mobility pattern of proteins in cells. This chapter will consolidate on the applications of various well-established microscopy techniques in flavivirus research, and discuss how recently developed microscopy techniques can potentially help advance our understanding in these membrane viruses. Copyright © 2013 Elsevier Ltd. All rights reserved.

Beta systems error analysis

NASA Technical Reports Server (NTRS)

1984-01-01

The atmospheric backscatter coefficient, beta, measured with an airborne CO Laser Doppler Velocimeter (LDV) system operating in a continuous wave, focussed model is discussed. The Single Particle Mode (SPM) algorithm, was developed from concept through analysis of an extensive amount of data obtained with the system on board a NASA aircraft. The SPM algorithm is intended to be employed in situations where one particle at a time appears in the sensitive volume of the LDV. In addition to giving the backscatter coefficient, the SPM algorithm also produces as intermediate results the aerosol density and the aerosol backscatter cross section distribution. A second method, which measures only the atmospheric backscatter coefficient, is called the Volume Mode (VM) and was simultaneously employed. The results of these two methods differed by slightly less than an order of magnitude. The measurement uncertainties or other errors in the results of the two methods are examined.

Influence of breast milk polyamines on suckling rat immune system maturation.

PubMed

Pérez-Cano, Francisco J; González-Castro, Ana; Castellote, Cristina; Franch, Angels; Castell, Margarida

2010-02-01

The aim of this study was to ascertain whether the supplementation of polyamines present in breast milk, i.e. spermine (SPM) and spermidine (SPD), influenced the post-natal maturation of the systemic and intestinal immune system in rats. From birth, pups daily received SPM or SPD. At 5, 11 and 18 days old, small intestine intraepithelial lymphocytes (IEL), lamina propria lymphocytes (LPL) and splenocytes were phenotypically characterized. SPM and, less evidently, SPD accelerated the maturation of CD8+ IEL, and enhanced the presence of intraepithelial NK cells and IEL related with specific immune responses on the proximal and distal small intestine, respectively. Polyamines increased the percentage of more mature CD4+ LPL and enhanced the early presence of splenic B cells and, later, that of NK cells. However, no effect on Ig-secretory function was detected. These results suggest that breast milk polyamines improve the maturation of the rat intestinal and systemic immune system.

Silver behaviour along the salinity gradient of the Gironde Estuary.

PubMed

Lanceleur, Laurent; Schäfer, Jörg; Blanc, Gérard; Coynel, Alexandra; Bossy, Cécile; Baudrimont, Magalie; Glé, Corine; Larrose, Aurélie; Renault, Sophie; Strady, Emilie

2013-03-01

Dissolved and particulate Ag concentrations (Ag(D) and Ag(P), respectively) were measured in surface water and suspended particulate matter (SPM) along the salinity gradient of the Gironde Estuary, South West France, during three cruises (2008-2009) covering contrasting hydrological conditions, i.e. two cruises during intermediate and one during high freshwater discharge (~740 and ~2,300 m(3)/s). Silver distribution reflected non-conservative behaviour with 60-70 % of Ag(P) in freshwater particles being desorbed by chlorocomplexation. The amount of Ag(P) desorbed was similar to the so-called reactive, potentially bioavailable Ag(P) fraction (60 ± 4 %) extracted from river SPM by 1 M HCl. Both Ag(P) (0.22 ± 0.05 mg/kg) and Ag(P)/Th(P) (0.025-0.028) in the residual fraction of fluvial and estuarine SPM were similar to those in SPM from the estuary mouth and in coastal sediments from the shelf off the Gironde Estuary, indicating that chlorocomplexation desorbs the reactive Ag(P). The data show that desorption of reactive Ag(P) mainly occurs inside the estuary during low and intermediate discharge, whereas expulsion of partially Ag(P)-depleted SPM (Ag(P)/Th(P) ~0.040) during the flood implies ongoing desorption in the coastal ocean, e.g. in the nearby oyster production areas (Marennes-Oléron Bay). The highest Ag(D) levels (6-8 ng/L) occurred in the mid-salinity range (15-20) of the Gironde Estuary and were decoupled from freshwater discharge. In the maximum turbidity zone, Ag(D) were at minimum, showing that high SPM concentrations (a) induce Ag(D) adsorption in estuarine freshwater and (b) counterbalance Ag(P) desorption in the low salinity range (1-3). Accordingly, Ag behaviour in turbid estuaries appears to be controlled by the balance between salinity and SPM levels. The first estimates of daily Ag(D) net fluxes for the Gironde Estuary (Boyle's method) showed relatively stable theoretical Ag(D) at zero salinity (Ag (D) (0) = 25-30 ng/L) for the contrasting hydrological situations. Accordingly, Ag(D) net fluxes were very similar for the situations with intermediate discharge (1.7 and 1.6 g/day) and clearly higher during the flood (5.0 g/day) despite incomplete desorption. Applying Ag (D) (0) to the annual freshwater inputs provided an annual net Ag(D) flux (0.64-0.89 t/year in 2008 and 0.56-0.77 t/year in 2009) that was 12-50 times greater than the Ag(D) gross flux. This estimate was consistent with net Ag(D) flux estimates obtained from gross Ag(P) flux considering 60 % desorption in the estuarine salinity gradient.

How much suspended particulate matter enters long-term in-channel storage?

NASA Astrophysics Data System (ADS)

Dietrich, Stephan; Kleisinger, Carmen; Kehl, Nora; Schubert, Birgit; Hillebrand, Gudrun

2017-04-01

The route of suspended particulate matter (SPM) downstream rivers strongly depends on discharge conditions and involves transport times and periods with resting times in deposits e.g. at areas with low-flow conditions near the channel bed. It is, however, difficult to estimate the contribution of SPM on the bed load. In this study, particle-bound polychlorinated biphenyls (PCB), which were released by an incident in the Elbe river (Central Europe) in spring 2015, could be used as unique tracer for transport pathways of SPM along the whole river stretch (over 700 km length), including low mountain ranges, lowlands, and the estuary. In 2015 the Elbe River was characterized by low-discharge conditions. Thus, the export of SPM on flood plains was strongly limited. The incident was monitored by concentration measurements of seven indicator PCB congeners along the inland part of the Elbe River as well as in the Elbe estuary. Data from ten monitoring stations (settling tanks) are considered. The total PCB load is calculated for all stations on the basis of monthly contaminant concentrations and daily suspended sediment concentrations. Monte-Carlo simulations assess the uncertainties of the calculated load. It is shown that the ratio of high versus low chlorinated PCB congeners is a suitable tracer to distinguish the PCB load of the incident from the long-term background signal (hereafter PCB6 ratio). We demonstrate that both the load of PCB as well as its chemical fingerprint allows the estimation of transport durations for the transport processes involved. Only a little part of the suspension has been transported via wash load. The PCB6 ratio is used to estimate mean transport velocities of the wash load fraction. A direct transport of wash load via the mean flow velocity of the water was not observed. Shortly after the incident, the PCB6 ratio was monitored 257 km downstream of the incident site in April 2015, in May first occurrence was monitored 514 km downstream of the incident site and in July it reaches the tidal weir 626 km downstream and enters the estuary. Here the transport velocity strongly decreases and the PCB6 ratio was not detected 25 km downstream the tidal weir before December 2015. The major part of the PCB-marked suspension is transported via suspended load. Interestingly, the reduction of total PCB tagged SPM load within the first 514 km downstream of the incident site indicates that roughly 75% of the annual SPM load (of the most upstream monitoring station located 43 km downstream of the incident site) is stored in the sediments of the Elbe River, suggesting that suspended sediment in transport enters storage after a relatively short distance. Once SPM settles, significant storage can occur over decadal time scales.

Method for analysis of psychopharmaceuticals in real industrial wastewater and groundwater with suspended organic particulate matter using solid phase extraction disks extraction and ultra-high performance liquid chromatography/time-of-flight mass spectrometry.

PubMed

Křesinová, Zdena; Linhartová, Lucie; Petrů, Klára; Krejčová, Lucie; Šrédlová, Kamila; Lhotský, Ondřej; Kameník, Zdeněk; Cajthaml, Tomáš

2016-04-01

A rapid and reliable analytical method was developed for the quantitative determination of psychopharmaceuticals, their precursors and by-products in real contaminated samples from a pharmaceutical company in Olomouc (Czech Republic), based on SPE disk extraction and detection by ultra performance liquid chromatography, combined with time-of-flight mass spectrometry. The target compounds were quantified in the real whole-water samples (water including suspended particles), both in the presence of suspended particulate matter (SPM) and high concentrations of other organic pollutants. A total of nine compounds were analyzed which consisted of three commonly used antidepressants (tricyclic antidepressants and antipsychotics), one antitussive agent and five by-products or precursors. At first, the SPE disk method was developed for the extraction of water samples (dissolved analytes, recovery 84-104%) and pressurised liquid extraction technique was verified for solid matrices (sludge samples, recovery 81-95%). In order to evaluate the SPE disk technique for whole water samples containing SPM, non contaminated groundwater samples were also loaded with different amounts (100 and 300mgL(-1)) of real contaminated sludge originating from the same locality. The recoveries from the whole-water samples obtained by SPE disk method ranged between 67 and 119% after the addition of the most contaminated sludge. The final method was applied to several real groundwater (whole-water) samples from the industrial area and high concentrations (up to 10(3)μgL(-1)) of the target compounds were detected. The results of this study document and indicate the feasibility of the SPE disk method for analysis of groundwater. Copyright © 2016 Elsevier B.V. All rights reserved.

A quantitative analysis of the polyamine in lung cancer patient fingernails by LC-ESI-MS/MS.

PubMed

Min, Jun Zhe; Matsumoto, Akihito; Li, Gao; Jiang, Ying-Zi; Yu, Hai-Fu; Todoroki, Kenichiro; Inoue, Koichi; Toyo'oka, Toshimasa

2014-04-01

A quantitative analysis of polyamines in lung cancer patient fingernails by the combination of 4-(N,N-dimethylaminosulfonyl)-7-fluoro-2,1,3-benzoxadiazole derivatives and liquid chromatography-electrospray ionization tandem mass spectrometry is described. The reaction of the reagent with eight kinds of polyamines, that is, N(1) -acetylputrescine (N(1) -actPUT), N(8) -acetylspermidine, N(1) -acetylspermine, 1,3-diaminopropane, putrescine (PUT), cadaverine, spermidine and spermine (SPM) effectively occurs at 60 °C for 30 min. The detection limits (signal-to-noise ratio 5) were 5-100 fmol. A good linearity was achieved from the calibration curves, which was obtained by plotting the peak area ratios of the analytes relative to the internal standard (IS), that is, 1,6-diaminohexane, vs the injected amounts of polyamines (r(2)  > 0.996), and the intra-day and inter-day assay precisions were <9.84%. Furthermore, the recoveries (%) of the polyamines spiked in the human fingernails were 89.14-110.64. The present method was applied to human fingernail samples from 17 lung cancer patients and 39 healthy volunteers. The polyamine concentration was different based on the gender, that is, the N(1) -actPUT and PUT contents were 3.10 times and 2.56 times higher in healthy men than in women, respectively. Additionally, in the lung cancer patient group, as compared with the healthy volunteers, the concentrations of SPM had a statistically significant (p < 0.05) correlation. Therefore, because the proposed method provides a good mass accuracy and the trace detection of the polyamines in human fingernails, this analytical technique could be a noninvasive technique to assist in the diagnosis and assessment of disease activity in lung cancer patients. Copyright © 2013 John Wiley & Sons, Ltd.

Application of scanning acoustic microscopy to advanced structural ceramics

NASA Technical Reports Server (NTRS)

Vary, Alex; Klima, Stanley J.

1987-01-01

A review is presentod of research investigations of several acoustic microscopy techniques for application to structural ceramics for advanced heat engines. Results obtained with scanning acoustic microscopy (SAM), scanning laser acoustic microscopy (SLAM), scanning electron acoustic microscopy (SEAM), and photoacoustic microscopy (PAM) are compared. The techniques were evaluated on research samples of green and sintered monolithic silicon nitrides and silicon carbides in the form of modulus-of-rupture bars containing deliberately introduced flaws. Strengths and limitations of the techniques are described with emphasis on statistics of detectability of flaws that constitute potential fracture origins.

Progress in the Correlative Atomic Force Microscopy and Optical Microscopy

PubMed Central

Zhou, Lulu; Cai, Mingjun; Tong, Ti; Wang, Hongda

2017-01-01

Atomic force microscopy (AFM) has evolved from the originally morphological imaging technique to a powerful and multifunctional technique for manipulating and detecting the interactions between molecules at nanometer resolution. However, AFM cannot provide the precise information of synchronized molecular groups and has many shortcomings in the aspects of determining the mechanism of the interactions and the elaborate structure due to the limitations of the technology, itself, such as non-specificity and low imaging speed. To overcome the technical limitations, it is necessary to combine AFM with other complementary techniques, such as fluorescence microscopy. The combination of several complementary techniques in one instrument has increasingly become a vital approach to investigate the details of the interactions among molecules and molecular dynamics. In this review, we reported the principles of AFM and optical microscopy, such as confocal microscopy and single-molecule localization microscopy, and focused on the development and use of correlative AFM and optical microscopy. PMID:28441775

Search for Open binaries in the Southern Celestial Hemisphere using SPM4

NASA Astrophysics Data System (ADS)

Dávila, E.; Vieira, K.; Rosales, K.

2018-01-01

Open binaries' weak gravitational binding makes them vulnerable to any perturbation, turning them into excellent probes of the gravitational field where they are located. Currently there are only a few hundreds known or suspected open binaries, therefore a search for more of these systems is highly encouraging by looking for pairs of stars with common proper motions in an extensive, deep, and high quality astrometric catalog such as the SPM4 (Girard et al. 2011).

SPM and XPM crosstalk in WDM systems with DRA: Channel spacing and attenuation effects

NASA Astrophysics Data System (ADS)

Morsy, Emadeldeen; Fayed, Heba A.; Abd El Aziz, Ahmed; Aly, Moustafa H.

2018-06-01

This paper presents a theoretical analysis of a closed formula for nonlinear crosstalk due to self-phase modulation (SPM) and cross phase modulation (XPM) in wavelength division multiplexing (WDM) systems. The influence of channel spacing and attenuation on the system behavior is modeled and investigated. The system under consideration is a standard single-mode fiber (SSMF) with a single-span distributed Raman amplifier (DRA) and is operating at 100 Gbps.

Synthesis and biological characterization of novel charge-deficient spermine analogues.

PubMed

Weisell, Janne; Hyvönen, Mervi T; Häkkinen, Merja R; Grigorenko, Nikolay A; Pietilä, Marko; Lampinen, Anita; Kochetkov, Sergey N; Alhonen, Leena; Vepsäläinen, Jouko; Keinänen, Tuomo A; Khomutov, Alex R

2010-08-12

Biogenic polyamines, spermidine and spermine, are positively charged at physiological pH. They are present in all cells and essential for their growth and viability. Here we synthesized three novel derivatives of the isosteric charge-deficient spermine analogue 1,12-diamino-3,6,9-triazadodecane (SpmTrien, 5a) that are N(1)-Ac-SpmTrien (5c), N(12)-Ac-SpmTrien (5b), and N(1),N(12)-diethyl-1,12-diamino-3,6,9-triazadodecane (N(1),N(12)-Et(2)-SpmTrien, 5d). 5a and 5d readily accumulated in DU145 cells at the same concentration range as natural polyamines and moderately competed for the uptake with putrescine (1) but not with spermine (4a) or spermidine (2). 5a efficiently down-regulated ornithine decarboxylase and decreased polyamine levels, while 5d proved to be inefficient, compared with N(1),N(11)-diethylnorspermine (6). None of the tested analogues were substrates for human recombinant spermine oxidase, but those having free aminoterminus, including 1,8-diamino-3,6-diazaoctane (Trien, 3a), were acetylated by mouse recombinant spermidine/spermine N(1)-acetyltransferase. 5a was acetylated to 5c and 5b, and the latter was further metabolized by acetylpolyamine oxidase to 3a, a drug used to treat Wilson's disease. Thus, 5a is a bioactive precursor of 3a with enhanced bioavailability.

Quantitative comparisons of three automated methods for estimating intracranial volume: A study of 270 longitudinal magnetic resonance images.

PubMed

Shang, Xiaoyan; Carlson, Michelle C; Tang, Xiaoying

2018-04-30

Total intracranial volume (TIV) is often used as a measure of brain size to correct for individual variability in magnetic resonance imaging (MRI) based morphometric studies. An adjustment of TIV can greatly increase the statistical power of brain morphometry methods. As such, an accurate and precise TIV estimation is of great importance in MRI studies. In this paper, we compared three automated TIV estimation methods (multi-atlas likelihood fusion (MALF), Statistical Parametric Mapping 8 (SPM8) and FreeSurfer (FS)) using longitudinal T1-weighted MR images in a cohort of 70 older participants at elevated sociodemographic risk for Alzheimer's disease. Statistical group comparisons in terms of four different metrics were performed. Furthermore, sex, education level, and intervention status were investigated separately for their impacts on the TIV estimation performance of each method. According to our experimental results, MALF was the least susceptible to atrophy, while SPM8 and FS suffered a loss in precision. In group-wise analysis, MALF was the least sensitive method to group variation, whereas SPM8 was particularly sensitive to sex and FS was unstable with respect to education level. In terms of effectiveness, both MALF and SPM8 delivered a user-friendly performance, while FS was relatively computationally intensive. Copyright © 2018 Elsevier B.V. All rights reserved.

Quantitative analysis of diffusion tensor imaging (DTI) using statistical parametric mapping (SPM) for brain disorders

NASA Astrophysics Data System (ADS)

Lee, Jae-Seung; Im, In-Chul; Kang, Su-Man; Goo, Eun-Hoe; Kwak, Byung-Joon

2013-07-01

This study aimed to quantitatively analyze data from diffusion tensor imaging (DTI) using statistical parametric mapping (SPM) in patients with brain disorders and to assess its potential utility for analyzing brain function. DTI was obtained by performing 3.0-T magnetic resonance imaging for patients with Alzheimer's disease (AD) and vascular dementia (VD), and the data were analyzed using Matlab-based SPM software. The two-sample t-test was used for error analysis of the location of the activated pixels. We compared regions of white matter where the fractional anisotropy (FA) values were low and the apparent diffusion coefficients (ADCs) were increased. In the AD group, the FA values were low in the right superior temporal gyrus, right inferior temporal gyrus, right sub-lobar insula, and right occipital lingual gyrus whereas the ADCs were significantly increased in the right inferior frontal gyrus and right middle frontal gyrus. In the VD group, the FA values were low in the right superior temporal gyrus, right inferior temporal gyrus, right limbic cingulate gyrus, and right sub-lobar caudate tail whereas the ADCs were significantly increased in the left lateral globus pallidus and left medial globus pallidus. In conclusion by using DTI and SPM analysis, we were able to not only determine the structural state of the regions affected by brain disorders but also quantitatively analyze and assess brain function.

A Singular Perturbation Approach for Time-Domain Assessment of Phase Margin

NASA Technical Reports Server (NTRS)

Zhu, J. Jim; Yang, Xiaojing; Hodel, A Scottedward

2010-01-01

This paper considers the problem of time-domain assessment of the Phase Margin (PM) of a Single Input Single Output (SISO) Linear Time-Invariant (LTI) system using a singular perturbation approach, where a SISO LTI fast loop system, whose phase lag increases monotonically with frequency, is introduced into the loop as a singular perturbation with a singular perturbation (time-scale separation) parameter Epsilon. First, a bijective relationship between the Singular Perturbation Margin (SPM) max and the PM of the nominal (slow) system is established with an approximation error on the order of Epsilon(exp 2). In proving this result, relationships between the singular perturbation parameter Epsilon, PM of the perturbed system, PM and SPM of the nominal system, and the (monotonically increasing) phase of the fast system are also revealed. These results make it possible to assess the PM of the nominal system in the time-domain for SISO LTI systems using the SPM with a standardized testing system called "PM-gauge," as demonstrated by examples. PM is a widely used stability margin for LTI control system design and certification. Unfortunately, it is not applicable to Linear Time-Varying (LTV) and Nonlinear Time-Varying (NLTV) systems. The approach developed here can be used to establish a theoretical as well as practical metric of stability margin for LTV and NLTV systems using a standardized SPM that is backward compatible with PM.

Polyamines Regulate Strawberry Fruit Ripening by Abscisic Acid, Auxin, and Ethylene.

PubMed

Guo, Jiaxuan; Wang, Shufang; Yu, Xiaoyang; Dong, Rui; Li, Yuzhong; Mei, Xurong; Shen, Yuanyue

2018-05-01

Polyamines (PAs) participate in many plant growth and developmental processes, including fruit ripening. However, it is not clear whether PAs play a role in the ripening of strawberry ( Fragaria ananassa ), a model nonclimacteric plant. Here, we found that the content of the PA spermine (Spm) increased more sharply after the onset of fruit coloration than did that of the PAs putrescine (Put) or spermidine (Spd). Spm dominance in ripe fruit resulted from abundant transcripts of a strawberry S -adenosyl-l-Met decarboxylase gene ( FaSAMDC ), which encodes an enzyme that generates a residue needed for PA biosynthesis. Exogenous Spm and Spd promoted fruit coloration, while exogenous Put and a SAMDC inhibitor inhibited coloration. Based on transcriptome data, up- and down-regulation of FaSAMDC expression promoted and inhibited ripening, respectively, which coincided with changes in several physiological parameters and their corresponding gene transcripts, including firmness, anthocyanin content, sugar content, polyamine content, auxin (indole-3-acetic acid [IAA]) content, abscisic acid (ABA) content, and ethylene emission. Using isothermal titration calorimetry, we found that FaSAMDC also had a high enzymatic activity with a K d of 1.7 × 10 -3 m In conclusion, PAs, especially Spm, regulate strawberry fruit ripening in an ABA-dominated, IAA-participating, and ethylene-coordinated manner, and FaSAMDC plays an important role in ripening. © 2018 American Society of Plant Biologists. All Rights Reserved.

A knowledge-guided active model method of cortical structure segmentation on pediatric MR images.

PubMed

Shan, Zuyao Y; Parra, Carlos; Ji, Qing; Jain, Jinesh; Reddick, Wilburn E

2006-10-01

To develop an automated method for quantification of cortical structures on pediatric MR images. A knowledge-guided active model (KAM) approach was proposed with a novel object function similar to the Gibbs free energy function. Triangular mesh models were transformed to images of a given subject by maximizing entropy, and then actively slithered to boundaries of structures by minimizing enthalpy. Volumetric results and image similarities of 10 different cortical structures segmented by KAM were compared with those traced manually. Furthermore, the segmentation performances of KAM and SPM2, (statistical parametric mapping, a MATLAB software package) were compared. The averaged volumetric agreements between KAM- and manually-defined structures (both 0.95 for structures in healthy children and children with medulloblastoma) were higher than the volumetric agreement for SPM2 (0.90 and 0.80, respectively). The similarity measurements (kappa) between KAM- and manually-defined structures (0.95 and 0.93, respectively) were higher than those for SPM2 (both 0.86). We have developed a novel automatic algorithm, KAM, for segmentation of cortical structures on MR images of pediatric patients. Our preliminary results indicated that when segmenting cortical structures, KAM was in better agreement with manually-delineated structures than SPM2. KAM can potentially be used to segment cortical structures for conformal radiation therapy planning and for quantitative evaluation of changes in disease or abnormality. Copyright (c) 2006 Wiley-Liss, Inc.

A landmark-based 3D calibration strategy for SPM

NASA Astrophysics Data System (ADS)

Ritter, Martin; Dziomba, Thorsten; Kranzmann, Axel; Koenders, Ludger

2007-02-01

We present a new method for the complete three-dimensional (3D) calibration of scanning probe microscopes (SPM) and other high-resolution microscopes, e.g., scanning electron microscopes (SEM) and confocal laser scanning microscopes (CLSM), by applying a 3D micrometre-sized reference structure with the shape of a cascade slope-step pyramid. The 3D reference structure was produced by focused ion beam induced metal deposition. In contrast to pitch featured calibration procedures that require separate lateral and vertical reference standards such as gratings and step height structures, the new method includes the use of landmarks, which are well established in calibration and measurement tasks on a larger scale. However, the landmarks applied to the new 3D reference structures are of sub-micrometre size, the so-called 'nanomarkers'. The nanomarker coordinates are used for a geometrical calibration of the scanning process of SPM as well as of other instrument types such as SEM and CLSM. For that purpose, a parameter estimation routine involving three scale factors and three coupling factors has been developed that allows lateral and vertical calibration in only one sampling step. With this new calibration strategy, we are able to detect deviations of SPM lateral scaling errors as well as coupling effects causing, e.g., a lateral coordinate shift depending on the measured height position of the probe.

Progress on Poverty? New Estimates of Historical Trends Using an Anchored Supplemental Poverty Measure

PubMed Central

Wimer, Christopher; Fox, Liana; Garfinkel, Irwin; Kaushal, Neeraj; Waldfogel, Jane

2016-01-01

This study examines historical trends in poverty using an anchored version of the U.S. Census Bureau’s recently developed Research Supplemental Poverty Measure (SPM) estimated back to 1967. Although the SPM is estimated each year using a quasi-relative poverty threshold that varies over time with changes in families’ expenditures on a core basket of goods and services, this study explores trends in poverty using an absolute, or anchored, SPM threshold. We believe the anchored measure offers two advantages. First, setting the threshold at the SPM’s 2012 levels and estimating it back to 1967, adjusted only for changes in prices, is more directly comparable to the approach taken in official poverty statistics. Second, it allows for a better accounting of the roles that social policy, the labor market, and changing demographics play in trends in poverty rates over time, given that changes in the threshold are held constant. Results indicate that unlike official statistics that have shown poverty rates to be fairly flat since the 1960s, poverty rates have dropped by 40 % when measured using a historical anchored SPM over the same period. Results obtained from comparing poverty rates using a pretax/pretransfer measure of resources versus a posttax/posttransfer measure of resources further show that government policies, not market incomes, are driving the declines observed over time. PMID:27352076

Comparative morphology analysis of live blood platelets using scanning ion conductance and robotic dark-field microscopy.

PubMed

Kraus, Max-Joseph; Seifert, Jan; Strasser, Erwin F; Gawaz, Meinrad; Schäffer, Tilman E; Rheinlaender, Johannes

2016-09-01

Many conventional microscopy techniques for investigating platelet morphology such as electron or fluorescence microscopy require highly invasive treatment of the platelets such as fixation, drying and metal coating or staining. Here, we present two unique but entirely different microscopy techniques for direct morphology analysis of live, unstained platelets: scanning ion conductance microscopy (SICM) and robotic dark-field microscopy (RDM). We demonstrate that both techniques allow for a quantitative evaluation of the morphological features of live adherent platelets. We show that their morphology can be quantified by both techniques using the same geometric parameters and therefore can be directly compared. By imaging the same identical platelets subsequently with SICM and RDM, we found that area, perimeter and circularity of the platelets are directly correlated between SICM and dark-field microscopy (DM), while the fractal dimension (FD) differed between the two microscopy techniques. We show that SICM and RDM are both valuable tools for the ex vivo investigation of the morphology of live platelets, which might contribute to new insights into the physiological and pathophysiological role of platelet spreading.

Properties of coarse particles in suspended particulate matter of the North Yellow Sea during summer

NASA Astrophysics Data System (ADS)

Zhang, Kainan; Wang, Zhenyan; Li, Wenjian; Yan, Jun

2018-01-01

Fine particles in seawater commonly form large porous aggregates. Aggregate density and settling velocity determine the behavior of this suspended particulate matter (SPM) within the water column. However, few studies of aggregate particles over a continental shelf have been undertaken. In our case study, properties of aggregate particles, including size and composition, over the continental shelf of the North Yellow Sea were investigated. During a scientific cruise in July 2016, in situ effective particle size distributions of SPM at 10 stations were measured, while temperature and turbidity measurements and samples of water were obtained from surface, middle, and bottom layers. Dispersed and inorganic particle size distributions were determined in the laboratory. The in situ SPM was divided into (1) small particles (<32 μm), (2) medium particles (32-256 μm) and (3) large particles (>256 μm). Large particles and medium particles dominated the total volume concentrations (VCs) of in situ SPM. After dispersion, the VCs of medium particles decreased to low values (<0.1 μL/L). The VCs of large particles in the surface and middle layers also decreased markedly, although they had higher peak values (0.1-1 μL/L). This suggests that almost all in situ medium particles and some large particles were aggregated, while other large particles were single particles. Correlation analysis showed that primary particles <32 μm influenced the formation of these aggregates. Microscopic examination revealed that these aggregates consisted of both organic and inorganic fine particles, while large particles were mucus-bound organic aggregates or individual plankton. The vertical distribution of coarser particles was clearly related to water stratification. Generally, medium aggregate particles were dominant in SPM of the bottom layer. A thermocline blocked resuspension of fine material into upper layers, yielding low VCs of medium-sized aggregate particles in the surface layer. Abundant large biogenic particles were present in both surface and middle layers.

Quantifying uncertainty in the measurement of arsenic in suspended particulate matter by Atomic Absorption Spectrometry with hydride generator

PubMed Central

2011-01-01

Arsenic is the toxic element, which creates several problems in human being specially when inhaled through air. So the accurate and precise measurement of arsenic in suspended particulate matter (SPM) is of prime importance as it gives information about the level of toxicity in the environment, and preventive measures could be taken in the effective areas. Quality assurance is equally important in the measurement of arsenic in SPM samples before making any decision. The quality and reliability of the data of such volatile elements depends upon the measurement of uncertainty of each step involved from sampling to analysis. The analytical results quantifying uncertainty gives a measure of the confidence level of the concerned laboratory. So the main objective of this study was to determine arsenic content in SPM samples with uncertainty budget and to find out various potential sources of uncertainty, which affects the results. Keeping these facts, we have selected seven diverse sites of Delhi (National Capital of India) for quantification of arsenic content in SPM samples with uncertainty budget following sampling by HVS to analysis by Atomic Absorption Spectrometer-Hydride Generator (AAS-HG). In the measurement of arsenic in SPM samples so many steps are involved from sampling to final result and we have considered various potential sources of uncertainties. The calculation of uncertainty is based on ISO/IEC17025: 2005 document and EURACHEM guideline. It has been found that the final results mostly depend on the uncertainty in measurement mainly due to repeatability, final volume prepared for analysis, weighing balance and sampling by HVS. After the analysis of data of seven diverse sites of Delhi, it has been concluded that during the period from 31st Jan. 2008 to 7th Feb. 2008 the arsenic concentration varies from 1.44 ± 0.25 to 5.58 ± 0.55 ng/m3 with 95% confidence level (k = 2). PMID:21466671

[Three-dimensional reconstruction of functional brain images].

PubMed

Inoue, M; Shoji, K; Kojima, H; Hirano, S; Naito, Y; Honjo, I

1999-08-01

We consider PET (positron emission tomography) measurement with SPM (Statistical Parametric Mapping) analysis to be one of the most useful methods to identify activated areas of the brain involved in language processing. SPM is an effective analytical method that detects markedly activated areas over the whole brain. However, with the conventional presentations of these functional brain images, such as horizontal slices, three directional projection, or brain surface coloring, makes understanding and interpreting the positional relationships among various brain areas difficult. Therefore, we developed three-dimensionally reconstructed images from these functional brain images to improve the interpretation. The subjects were 12 normal volunteers. The following three types of images were constructed: 1) routine images by SPM, 2) three-dimensional static images, and 3) three-dimensional dynamic images, after PET images were analyzed by SPM during daily dialog listening. The creation of images of both the three-dimensional static and dynamic types employed the volume rendering method by VTK (The Visualization Toolkit). Since the functional brain images did not include original brain images, we synthesized SPM and MRI brain images by self-made C++ programs. The three-dimensional dynamic images were made by sequencing static images with available software. Images of both the three-dimensional static and dynamic types were processed by a personal computer system. Our newly created images showed clearer positional relationships among activated brain areas compared to the conventional method. To date, functional brain images have been employed in fields such as neurology or neurosurgery, however, these images may be useful even in the field of otorhinolaryngology, to assess hearing and speech. Exact three-dimensional images based on functional brain images are important for exact and intuitive interpretation, and may lead to new developments in brain science. Currently, the surface model is the most common method of three-dimensional display. However, the volume rendering method may be more effective for imaging regions such as the brain.

Voxel-based statistical analysis of cerebral blood flow using Tc-99m ECD brain SPECT in patients with traumatic brain injury: group and individual analyses.

PubMed

Shin, Yong Beom; Kim, Seong-Jang; Kim, In-Ju; Kim, Yong-Ki; Kim, Dong-Soo; Park, Jae Heung; Yeom, Seok-Ran

2006-06-01

Statistical parametric mapping (SPM) was applied to brain perfusion single photon emission computed tomography (SPECT) images in patients with traumatic brain injury (TBI) to investigate regional cerebral abnormalities compared to age-matched normal controls. Thirteen patients with TBI underwent brain perfusion SPECT were included in this study (10 males, three females, mean age 39.8 +/- 18.2, range 21 - 74). SPM2 software implemented in MATLAB 5.3 was used for spatial pre-processing and analysis and to determine the quantitative differences between TBI patients and age-matched normal controls. Three large voxel clusters of significantly decreased cerebral blood perfusion were found in patients with TBI. The largest clusters were area including medial frontal gyrus (voxel number 3642, peak Z-value = 4.31, 4.27, p = 0.000) in both hemispheres. The second largest clusters were areas including cingulated gyrus and anterior cingulate gyrus of left hemisphere (voxel number 381, peak Z-value = 3.67, 3.62, p = 0.000). Other clusters were parahippocampal gyrus (voxel number 173, peak Z-value = 3.40, p = 0.000) and hippocampus (voxel number 173, peak Z-value = 3.23, p = 0.001) in the left hemisphere. The false discovery rate (FDR) was less than 0.04. From this study, group and individual analyses of SPM2 could clearly identify the perfusion abnormalities of brain SPECT in patients with TBI. Group analysis of SPM2 showed hypoperfusion pattern in the areas including medial frontal gyrus of both hemispheres, cingulate gyrus, anterior cingulate gyrus, parahippocampal gyrus and hippocampus in the left hemisphere compared to age-matched normal controls. Also, left parahippocampal gyrus and left hippocampus were additional hypoperfusion areas. However, these findings deserve further investigation on a larger number of patients to be performed to allow a better validation of objective SPM analysis in patients with TBI.

[Elaboration of the SPM template for the standardization of SPECT images with 123I-Ioflupane].

PubMed

García-Gómez, F J; García-Solís, D; Luis-Simón, F J; Marín-Oyaga, V A; Carrillo, F; Mir, P; Vázquez-Albertino, R J

2013-01-01

Statistical parametric mapping (SPM) is a widely used produced for normalization of functional images. This study has aimed to develop a normalization template of (123)I-Ioflupane SPECT-imaging DaTSCAN(®), GE Healthcare), not available in SPM5, and to validate it compared to other quantification methods. In order to write the template we retrospectively selected 26 subjects who had no evidence of nigrostriatal degeneration and whose age distribution was similar to that of the patients in the usual practice of our Department: 2 subjects (7.6%) were < 35 years, 9 between 35-65 years (34.6%) and 15 > 65 years (57.7%). All the studies were normalized with the T1-template available in SPM5 and an average image of the value was obtained for each voxel. For validation we analyzed 60 patients: 30 with idiopathic Parkinson's disease patients (iPD) with right involvement (66.83±12.20 years) and 30 with essential tremor patients (ET) (67.27±8.33 years). Specific uptake rates (SUR) of different striatal regions were compared after image normalization with our template and the application of a semiautomated VOIs-map created with Analyze v9.0 ((©)BIR, Mayo Clinic), against two quantification methods: a) manual adjustment of a ROIs-map drawn in Analyze, and b) semi-automated method (HERMES-BRASS) with normalization and implementation of VOIs-map. No statistically significant differences in the iPD/ET discriminatory capacity between the three methods analyzed were observed (p<0,001). The correlation of SUR after normalization with our «template» was higher than that obtained by method b) (R>0,871, p<0,001). This difference was greater in patients with PD. Our study demonstrates the efficacy of our SPM «template» for (123)I-Ioflupane SPECT-imaging, obtained from normalization with «T1-template». Copyright © 2012 Elsevier España, S.L. and SEMNIM. All rights reserved.

In vivo correlation mapping microscopy

NASA Astrophysics Data System (ADS)

McGrath, James; Alexandrov, Sergey; Owens, Peter; Subhash, Hrebesh; Leahy, Martin

2016-04-01

To facilitate regular assessment of the microcirculation in vivo, noninvasive imaging techniques such as nailfold capillaroscopy are required in clinics. Recently, a correlation mapping technique has been applied to optical coherence tomography (OCT), which extends the capabilities of OCT to microcirculation morphology imaging. This technique, known as correlation mapping optical coherence tomography, has been shown to extract parameters, such as capillary density and vessel diameter, and key clinical markers associated with early changes in microvascular diseases. However, OCT has limited spatial resolution in both the transverse and depth directions. Here, we extend this correlation mapping technique to other microscopy modalities, including confocal microscopy, and take advantage of the higher spatial resolution offered by these modalities. The technique is achieved as a processing step on microscopy images and does not require any modification to the microscope hardware. Results are presented which show that this correlation mapping microscopy technique can extend the capabilities of conventional microscopy to enable mapping of vascular networks in vivo with high spatial resolution in both the transverse and depth directions.

Presence of high-risk clones of OXA-23-producing Acinetobacter baumannii (ST79) and SPM-1-producing Pseudomonas aeruginosa (ST277) in environmental water samples in Brazil.

PubMed

Turano, Helena; Gomes, Fernando; Medeiros, Micheli; Oliveira, Silvane; Fontes, Lívia C; Sato, Maria I Z; Lincopan, Nilton

2016-09-01

This study reports the presence of hospital-associated high-risk lineages of OXA-23-producing ST79 Acinetobacter baumannii and SPM-1-producing ST277 Pseudomonas aeruginosa in urban rivers in Brazil. These findings indicate that urban rivers can act as reservoirs of clinically important multidrug-resistant bacteria, which constitute a potential risk to human and animal health. Copyright © 2016 Elsevier Inc. All rights reserved.

Controlled Atmosphere High Temperature SPM for electrochemical measurements

NASA Astrophysics Data System (ADS)

Vels Hansen, K.; Sander, C.; Koch, S.; Mogensen, M.

2007-03-01

A new controlled atmosphere high temperature SPM has been designed and build for the purpose of performing electrochemical measurements on solid oxide fuel cell materials. The first tests show that images can be obtained at a surface temperature of 465°C in air with a standard AFM AC probe. The aim is to produce images at a surface temperature of 800°C with electrically conducting ceramic probes as working electrodes that can be positioned at desired locations at the surface for electrochemical measurements.

Pinus sylvestris L. needle surface wettability parameters as indicators of atmospheric environment pollution impacts: Novel contact angle hysteresis methodology

NASA Astrophysics Data System (ADS)

Pogorzelski, Stanisław J.; Rochowski, Pawel; Szurkowski, Janusz

2014-02-01

An investigation of water contact angles (CAs), contact angle hysteresis (CAH) was carried out for 1-year to 4-year old needles (Pinus sylvestris) collected in urban (Gdansk) and rural (Karsin) locations using an original measuring technique based on the geometry of the drop on a vertical filament. Concentrations of air pollutants (SO2, NOx, C6H6, and suspended particular matter - SPM) currently considered to be most important in causing direct damage to vegetation were simultaneously monitored. A set of the surface wettability parameters: the apparent surface free energy γSV, adhesive film tension Π, work of adhesion WA, and spreading WS, were determined from CAH data using the approach developed by Chibowski (2003) to quantify the surface energetics of the needle substrata affected by aging and pollution impacts. This formalism relates the total apparent surface free energy of the solid γSV with only three measurable quantities: the surface tension of the probe liquid γLV and its advancing θA and receding θR contact angle hysteresis. Since CAH depends on the outermost wax layer surface roughness and spatial physicochemical heterogeneity of a solid surface, CA data were corrected using surface architecture profiles registered with confocal scanning laser microscopy. It was found that the roughness parameter r is significantly negatively correlated (R = -0.74) with the needle age (collected at Karsin). The needle surface aging process resulted in its surface hydrophilization (CA↓ and CAH↓ with γSV↑ and WA↑). A temporal evolution of the needles wettability was traced with the data point distribution in the 2D space of CAH plotted versus WS. The wettability parameters were closely correlated to pollutant concentrations as evidenced from Spearman's rank correlation procedure (R = 0.63-0.91; p < 0.05). The aim of the study was to validate the established CA methodology to create a new non-invasive, low-cost technique suitable for monitoring of structural changes at interfaces of biological systems.

SPM response to tide and river flow in the hyper-turbid Ems River

NASA Astrophysics Data System (ADS)

Winterwerp, Johan C.; Vroom, Julia; Wang, Zheng-B.; Krebs, Martin; Hendriks, Erik C. M.; van Maren, Dirk S.; Schrottke, Kerstin; Borgsmüller, Christine; Schöl, Andreas

2017-05-01

In this paper, we analyse the behaviour of fine sediments in the hyper-turbid Lower Ems River, with focus on the river's upper reaches, a stretch of about 25 km up-estuary of Terborg. Our analysis is based on long records of suspended particulate matter (SPM) from optical backscatter (OBS) measurements close to the bed at seven stations along the river, records of salinity and water level measurements at these stations, acoustic measurements on the vertical mud structure just up-estuary of Terborg and oxygen profiles in the lower 3 m of the water column close to Leerort and Terborg. Further, we use cross-sectionally averaged velocities computed with a calibrated numerical model. Distinction is made between four timescales, i.e. the semi-diurnal tidal timescale, the spring-neap tidal timescale, a timescale around an isolated peak in river flow (i.e. about 3 weeks) and a seasonal timescale. The data suggest that a pool of fluid/soft mud is present in these upper reaches, from up-estuary of Papenburg to a bit down-estuary of Terborg. Between Terborg and Gandersum, SPM values drop rapidly but remain high at a few gram per litre. The pool of fluid/soft mud is entrained/mobilized at the onset of flood, yielding SPM values of many tens gram per litre. This suspension is transported up-estuary with the flood. Around high water slack, part of the suspension settles, being remixed during ebb, while migrating down-estuary, but likely not much further than Terborg. Around low water slack, a large fraction of the sediment settles, reforming the pool of fluid mud. The rapid entrainment from the fluid mud layer after low water slack is only possible when the peak flood velocity exceeds a critical value of around 1 m/s, i.e. when the stratified water column seems to become internally supercritical. If the peak flood velocity does not reach this critical value, f.i. during neap tide, fluid mud is not entrained up to the OBS sensors. Thus, it is not classical tidal asymmetry, but the peak flood velocity itself which governs the hyper-turbid state in the Lower Ems River. The crucial role of river flow and river floods is in reducing these peak flood velocities. During elongated periods of high river flow, in e.g. wintertime, SPM concentrations reduce, and the soft mud deposits consolidate and possibly become locally armoured as well by sand washed in from the river. We have no observations that sediments are washed out of the hyper-turbid zone. Down-estuary of Terborg, where SPM values do not reach hyper-turbid conditions, the SPM dynamics are governed by classical tidal asymmetry and estuarine circulation. Hence, nowhere in the river, sediments are flushed from the upper reaches of the river into the Ems-Dollard estuary during high river flow events. However, exchange of sediment between river and estuary should occur because of tide-induced dispersion.

The Development of Teaching and Learning in Bright-Field Microscopy Technique

ERIC Educational Resources Information Center

Iskandar, Yulita Hanum P.; Mahmud, Nurul Ethika; Wahab, Wan Nor Amilah Wan Abdul; Jamil, Noor Izani Noor; Basir, Nurlida

2013-01-01

E-learning should be pedagogically-driven rather than technologically-driven. The objectives of this study are to develop an interactive learning system in bright-field microscopy technique in order to support students' achievement of their intended learning outcomes. An interactive learning system on bright-field microscopy technique was…

New positive feedback mechanism between boundary layer meteorology and secondary aerosol formation during severe haze events.

PubMed

Liu, Quan; Jia, Xingcan; Quan, Jiannong; Li, Jiayun; Li, Xia; Wu, Yongxue; Chen, Dan; Wang, Zifa; Liu, Yangang

2018-04-17

Severe haze events during which particulate matter (PM) increases quickly from tens to hundreds of microgram per cubic meter in 1-2 days frequently occur in China. Although it has been known that PM is influenced by complex interplays among emissions, meteorology, and physical and chemical processes, specific mechanisms remain elusive. Here, a new positive feedback mechanism between planetary boundary layer (PBL), relative humidity (RH), and secondary PM (SPM) formation is proposed based on a comprehensive field experiment and model simulation. The decreased PBL associated with increased PM increases RH by weakening the vertical transport of water vapor; the increased RH in turn enhances the SPM formation through heterogeneous aqueous reactions, which further enhances PM, weakens solar radiation, and decreases PBL height. This positive feedback, together with the PM-Radiation-PBL feedback, constitutes a key mechanism that links PM, radiation, PBL properties (e.g. PBL height and RH), and SPM formation, This mechanism is self-amplifying, leading to faster PM production, accumulation, and more severe haze pollution.

Seasonal changes of polycyclic aromatic hydrocarbons in response to hydrology and anthropogenic activities in the Pearl River estuary, China.

PubMed

Liu, Feng; Niu, Lixia; Chen, Hui; Li, Ping; Tian, Feng; Yang, Qingshu

2017-04-15

The behaviours of PAHs (containing 2-6 aromatic rings) in the Pearl River estuary were examined each month in 2011. This study was designed to investigate the abundance of 16 priority PAHs and their response to the seasonal dynamics of anthropogenic activities and hydrological cycles. Monthly mean concentrations of ∑ 16 PAHs in water and suspended particulate matter (SPM) were 88.31ng/L and 252.31ng/L respectively, with higher concentrations in the wet season (April to September). Heavy precipitation in the wet season resulted in relatively increased PAH input via riverine discharges and atmospheric deposition. Seasonal variations in suspended sediment concentration (SSC), temperature and salinity have considerably affected the PAH phase association. Higher SSC in the wet season contributed to higher concentration of the PAHs in SPM, and higher temperature and lower salinity facilitated desorption from SPM. The PAH sources were largely attributed to vehicular emissions, coal combustion and coke ovens. Copyright © 2017 Elsevier Ltd. All rights reserved.

Approaching total absorption of graphene strips using a c-Si subwavelength periodic membrane

NASA Astrophysics Data System (ADS)

Sang, Tian; Wang, Rui; Li, Junlang; Zhou, Jianyu; Wang, Yueke

2018-04-01

Approaching total absorption of graphene strips at near infrared using a crystalline-silicon (c-Si) subwavelength periodic membrane (SPM) is presented. The absorption in graphene strips in a c-Si SPM is enhanced by a resonant tip, which is resulted from the coupling between the guided mode and the radiation mode through symmetry breaking of the structure at near-normal incidence. The enhancement of the electric field intensity is increased 1939 times and the group velocity of light is decreased to 3.55 ×10-4c at resonance, and 99.3% absorption in graphene strips can be achieved by critical coupling at the incident angle of 2°. High absorption of the graphene strips can be maintained as the etching thickness, the strip width, and the period are altered. When this type of c-Si SPM with graphene strips is used in refractive index sensors, it shows excellent sensing properties due to its stable near-unity absorption.

Heavy metals in particulate and colloidal matter from atmospheric deposition of urban Guangzhou, South China.

PubMed

Huang, Wen; Duan, Dandan; Zhang, Yulong; Cheng, Hefa; Ran, Yong

2014-08-30

Suspended particulate matter (SPM) and colloidal matter (COM) in annual dry and wet deposition samples in urban Guangzhou were for the first time collected, and their trace metals were investigated by using inductively coupled plasma mass spectrometry (ICP-MS). The deposition flux of SPM and of metal elements varied largely among the investigated seasons, and reached the maximum in spring. The correlation analysis indicated that significant correlations existed among some of the metal elements in the deposition samples. The enrichment factors (EF) of metals in COM in the deposition ranging from 79.66 to 130,000 were much higher than those of SPM ranging from 1.65 to 286.48, indicating the important role of COM. The factor analysis showed that emissions from street dust, non-ferrous metal production, and heavy fuel oil were major sources of the trace metals. Positive matrix factorization (PMF) model was used to quantitatively estimate anthropogenic source. Copyright © 2013 Elsevier Ltd. All rights reserved.

Correlation mapping microscopy

NASA Astrophysics Data System (ADS)

McGrath, James; Alexandrov, Sergey; Owens, Peter; Subhash, Hrebesh M.; Leahy, Martin J.

2015-03-01

Changes in the microcirculation are associated with conditions such as Raynauds disease. Current modalities used to assess the microcirculation such as nailfold capillaroscopy are limited due to their depth ambiguity. A correlation mapping technique was recently developed to extend the capabilities of Optical Coherence Tomography to generate depth resolved images of the microcirculation. Here we present the extension of this technique to microscopy modalities, including confocal microscopy. It is shown that this correlation mapping microscopy technique can extend the capabilities of conventional microscopy to enable mapping of vascular networks in vivo with high spatial resolution.

Dancing with the Tides: Fluctuations of Coastal Phytoplankton Orchestrated by Different Oscillatory Modes of the Tidal Cycle

PubMed Central

Blauw, Anouk N.; Benincà, Elisa; Laane, Remi W. P. M.; Greenwood, Naomi; Huisman, Jef

2012-01-01

Population fluctuations are often driven by an interplay between intrinsic population processes and extrinsic environmental forcing. To investigate this interplay, we analyzed fluctuations in coastal phytoplankton concentration in relation to the tidal cycle. Time series of chlorophyll fluorescence, suspended particulate matter (SPM), salinity and temperature were obtained from an automated measuring platform in the southern North Sea, covering 9 years of data at a resolution of 12 to 30 minutes. Wavelet analysis showed that chlorophyll fluctuations were dominated by periodicities of 6 hours 12 min, 12 hours 25 min, 24 hours and 15 days, which correspond to the typical periodicities of tidal current speeds, the semidiurnal tidal cycle, the day-night cycle, and the spring-neap tidal cycle, respectively. During most of the year, chlorophyll and SPM fluctuated in phase with tidal current speed, indicative of alternating periods of sinking and vertical mixing of algal cells and SPM driven by the tidal cycle. Spring blooms slowly built up over several spring-neap tidal cycles, and subsequently expanded in late spring when a strong decline of the SPM concentration during neap tide enabled a temporary “escape” of the chlorophyll concentration from the tidal mixing regime. Our results demonstrate that the tidal cycle is a major determinant of phytoplankton fluctuations at several different time scales. These findings imply that high-resolution monitoring programs are essential to capture the natural variability of phytoplankton in coastal waters. PMID:23166639

Dancing with the tides: fluctuations of coastal phytoplankton orchestrated by different oscillatory modes of the tidal cycle.

PubMed

Blauw, Anouk N; Benincà, Elisa; Laane, Remi W P M; Greenwood, Naomi; Huisman, Jef

2012-01-01

Population fluctuations are often driven by an interplay between intrinsic population processes and extrinsic environmental forcing. To investigate this interplay, we analyzed fluctuations in coastal phytoplankton concentration in relation to the tidal cycle. Time series of chlorophyll fluorescence, suspended particulate matter (SPM), salinity and temperature were obtained from an automated measuring platform in the southern North Sea, covering 9 years of data at a resolution of 12 to 30 minutes. Wavelet analysis showed that chlorophyll fluctuations were dominated by periodicities of 6 hours 12 min, 12 hours 25 min, 24 hours and 15 days, which correspond to the typical periodicities of tidal current speeds, the semidiurnal tidal cycle, the day-night cycle, and the spring-neap tidal cycle, respectively. During most of the year, chlorophyll and SPM fluctuated in phase with tidal current speed, indicative of alternating periods of sinking and vertical mixing of algal cells and SPM driven by the tidal cycle. Spring blooms slowly built up over several spring-neap tidal cycles, and subsequently expanded in late spring when a strong decline of the SPM concentration during neap tide enabled a temporary "escape" of the chlorophyll concentration from the tidal mixing regime. Our results demonstrate that the tidal cycle is a major determinant of phytoplankton fluctuations at several different time scales. These findings imply that high-resolution monitoring programs are essential to capture the natural variability of phytoplankton in coastal waters.

fMRat: an extension of SPM for a fully automatic analysis of rodent brain functional magnetic resonance series.

PubMed

Chavarrías, Cristina; García-Vázquez, Verónica; Alemán-Gómez, Yasser; Montesinos, Paula; Pascau, Javier; Desco, Manuel

2016-05-01

The purpose of this study was to develop a multi-platform automatic software tool for full processing of fMRI rodent studies. Existing tools require the usage of several different plug-ins, a significant user interaction and/or programming skills. Based on a user-friendly interface, the tool provides statistical parametric brain maps (t and Z) and percentage of signal change for user-provided regions of interest. The tool is coded in MATLAB (MathWorks(®)) and implemented as a plug-in for SPM (Statistical Parametric Mapping, the Wellcome Trust Centre for Neuroimaging). The automatic pipeline loads default parameters that are appropriate for preclinical studies and processes multiple subjects in batch mode (from images in either Nifti or raw Bruker format). In advanced mode, all processing steps can be selected or deselected and executed independently. Processing parameters and workflow were optimized for rat studies and assessed using 460 male-rat fMRI series on which we tested five smoothing kernel sizes and three different hemodynamic models. A smoothing kernel of FWHM = 1.2 mm (four times the voxel size) yielded the highest t values at the somatosensorial primary cortex, and a boxcar response function provided the lowest residual variance after fitting. fMRat offers the features of a thorough SPM-based analysis combined with the functionality of several SPM extensions in a single automatic pipeline with a user-friendly interface. The code and sample images can be downloaded from https://github.com/HGGM-LIM/fmrat .

Dynamic Allocation of SPM Based on Time-Slotted Cache Conflict Graph for System Optimization

NASA Astrophysics Data System (ADS)

Wu, Jianping; Ling, Ming; Zhang, Yang; Mei, Chen; Wang, Huan

This paper proposes a novel dynamic Scratch-pad Memory allocation strategy to optimize the energy consumption of the memory sub-system. Firstly, the whole program execution process is sliced into several time slots according to the temporal dimension; thereafter, a Time-Slotted Cache Conflict Graph (TSCCG) is introduced to model the behavior of Data Cache (D-Cache) conflicts within each time slot. Then, Integer Nonlinear Programming (INP) is implemented, which can avoid time-consuming linearization process, to select the most profitable data pages. Virtual Memory System (VMS) is adopted to remap those data pages, which will cause severe Cache conflicts within a time slot, to SPM. In order to minimize the swapping overhead of dynamic SPM allocation, a novel SPM controller with a tightly coupled DMA is introduced to issue the swapping operations without CPU's intervention. Last but not the least, this paper discusses the fluctuation of system energy profit based on different MMU page size as well as the Time Slot duration quantitatively. According to our design space exploration, the proposed method can optimize all of the data segments, including global data, heap and stack data in general, and reduce the total energy consumption by 27.28% on average, up to 55.22% with a marginal performance promotion. And comparing to the conventional static CCG (Cache Conflicts Graph), our approach can obtain 24.7% energy profit on average, up to 30.5% with a sight boost in performance.

Evaluation of mobile digital light-emitting diode fluorescence microscopy in Hanoi, Viet Nam.

PubMed

Chaisson, L H; Reber, C; Phan, H; Switz, N; Nilsson, L M; Myers, F; Nhung, N V; Luu, L; Pham, T; Vu, C; Nguyen, H; Nguyen, A; Dinh, T; Nahid, P; Fletcher, D A; Cattamanchi, A

2015-09-01

Hanoi Lung Hospital, Hanoi, Viet Nam. To compare the accuracy of CellScopeTB, a manually operated mobile digital fluorescence microscope, with conventional microscopy techniques. Patients referred for sputum smear microscopy to the Hanoi Lung Hospital from May to September 2013 were included. Ziehl-Neelsen (ZN) smear microscopy, conventional light-emitting diode (LED) fluorescence microscopy (FM), CellScopeTB-based LED FM and Xpert(®) MTB/RIF were performed on sputum samples. The sensitivity and specificity of microscopy techniques were determined in reference to Xpert results, and differences were compared using McNemar's paired test of proportions. Of 326 patients enrolled, 93 (28.5%) were Xpert-positive for TB. The sensitivity of ZN microscopy, conventional LED FM, and CellScopeTB-based LED FM was respectively 37.6% (95%CI 27.8-48.3), 41.9% (95%CI 31.8-52.6), and 35.5% (95%CI 25.8-46.1). The sensitivity of CellScopeTB was similar to that of conventional LED FM (difference -6.5%, 95%CI -18.2 to 5.3, P = 0.33) and ZN microscopy (difference -2.2%, 95%CI -9.2 to 4.9, P = 0.73). The specificity was >99% for all three techniques. CellScopeTB performed similarly to conventional microscopy techniques in the hands of experienced TB microscopists. However, the sensitivity of all sputum microscopy techniques was low. Options enabled by digital microscopy, such as automated imaging with real-time computerized analysis, should be explored to increase sensitivity.

The dependence of estuarine turbidity on tidal intrusion length, tidal range and residence time

USGS Publications Warehouse

Uncles, R.J.; Stephens, J.A.; Smith, R.E.

2002-01-01

It is shown that there is a marked tendency for long, strongly tidal estuaries to have greater suspended particulate matter (SPM) concentrations within their high-turbidity regions than shorter estuaries with comparable tidal ranges at their mouths, or weakly tidal estuaries. Using consistently derived data from 44 estuaries in Europe and the Americas, contours of the logarithm of maximum estuarine SPM concentration are shown to be reasonably smooth when plotted against the logarithm of mean spring tidal range (at the estuary mouth) and the logarithm of estuarine tidal length. Predictions from the plot are compared with published observations made in the Delaware, Scheldt, Rio de la Plata, Gironde, Bay of Fundy, Changjiang (Yangtze), Amazon, Paros Lagoon and the Hawkesbury Estuary and it is shown that, qualitatively, there are no serious discrepancies. Short, weakly tidal estuaries are predicted to have very low 'intrinsic' SPM concentrations. High SPM concentrations in these estuaries would most likely be the result of either locally generated wave resuspension, high freshwater sediment loads due to freshets, or intruding seawater carrying suspended sediments derived from wave activity in the coastal zone. Application of a generic tidal model demonstrates that longer estuaries possess faster tidal currents for a given tidal range at their mouth and, in the presence of a supply of erodable fine sediment, therefore (by implication) produce greater concentrations of SPM that can be accumulated within a turbidity maximum. The same is true if the tidal range is increased for estuaries of a given length. These features are illustrated by comparing surveys of SPM data from two large estuaries possessing greatly different tidal ranges (the microtidal, medium turbidity Potomac and the macrotidal, highly turbid Humber-Ouse) and a third, much smaller but strongly tidal estuary (the low-turbidity Tweed). It is demonstrated that longer estuaries tend to have longer flushing times for solutes than shorter systems and that larger tides tend to reduce flushing times, although the tidal influence is secondary. Short, rapidly flushed estuaries quickly lose their erodable fine sediment to the coastal zone during freshets and during the ebbing currents of spring tides. Turbidity is therefore small during low runoff, low wave activity conditions. Very long, very slowly flushed estuaries are unlikely to lose a significant fraction of their resuspended sediments during freshets or individual ebb tides and are therefore able to accumulate large and increasing amounts of fine sediment in the long-term. Turbidity within them is therefore high during the fast currents of large spring tides. ?? 2002 Elsevier Science Ltd. All rights reserved.

The dependence of estuarine turbidity on tidal intrusion length, tidal range and residence time

USGS Publications Warehouse

Uncles, R.J.; Stephens, J.A.; Smith, R.E.

2002-01-01

It is shown that there is a marked tendency for long, strongly tidal estuaries to have greater suspended particulate matter (SPM) concentrations within their high-turbidity regions than shorter estuaries with comparable tidal ranges at their mouths, or weakly tidal estuaries. Using consistently derived data from 44 estuaries in Europe and the Americas, contours of the logarithm of maximum estuarine SPM concentration are shown to be reasonably smooth when plotted against the logarithm of mean spring tidal range (at the estuary mouth) and the logarithm of estuarine tidal length. Predictions from the plot are compared with published observations made in the Delaware, Scheldt, Rio de la Plata, Gironde, Bay of Fundy, Changjiang (Yangtze), Amazon, Patos Lagoon and the Hawkesbury Estuary and it is shown that, qualitatively, there are no serious discrepancies. Short, weakly tidal estuaries are predicted to have very low ‘intrinsic’ SPM concentrations. High SPM concentrations in these estuaries would most likely be the result of either locally generated wave resuspension, high freshwater sediment loads due to freshets, or intruding seawater carrying suspended sediments derived from wave activity in the coastal zone. Application of a generic tidal model demonstrates that longer estuaries possess faster tidal currents for a given tidal range at their mouth and, in the presence of a supply of erodable fine sediment, therefore (by implication) produce greater concentrations of SPM that can be accumulated within a turbidity maximum. The same is true if the tidal range is increased for estuaries of a given length. These features are illustrated by comparing surveys of SPM data from two large estuaries possessing greatly different tidal ranges (the microtidal, medium turbidity Potomac and the macrotidal, highly turbid Humber-Ouse) and a third, much smaller but strongly tidal estuary (the low-turbidity Tweed). It is demonstrated that longer estuaries tend to have longer flushing times for solutes than shorter systems and that larger tides tend to reduce flushing times, although the tidal influence is secondary. Short, rapidly flushed estuaries quickly lose their erodable fine sediment to the coastal zone during freshets and during the ebbing currents of spring tides. Turbidity is therefore small during low runoff, low wave activity conditions. Very long, very slowly flushed estuaries are unlikely to lose a significant fraction of their resuspended sediments during freshets or individual ebb tides and are therefore able to accumulate large and increasing amounts of fine sediment in the long-term. Turbidity within them is therefore high during the fast currents of large spring tides.

Using VIIRS/NPP and MODIS/Aqua data to provide a continuous record of suspended particulate matter in a highly turbid inland lake

NASA Astrophysics Data System (ADS)

Cao, Zhigang; Duan, Hongtao; Shen, Ming; Ma, Ronghua; Xue, Kun; Liu, Dong; Xiao, Qitao

2018-02-01

Inland lakes are generally an important source of drinking water, and information on their water quality needs to be obtained in real time. To date, Moderate-resolution imaging spectroradiometer (MODIS) data have played a critical, effective and long-term role in fulfilling this function. However, the MODIS instruments on board both the Terra and Aqua satellites have operated beyond their designed five-year mission lifespans (Terra was launched in 1999, whereas Aqua was launched in 2002), and these instruments may stop running at any time in the near future. The Visible Infrared Imager Radiometer Suite (VIIRS) on board the Suomi National Polar-Orbiting Partnership (Suomi NPP, which was launched in Oct 2011) is expected to provide a consistent, long-term data record and continue the series of observations initiated by MODIS. To date, few evaluations of the consistency between VIIRS and MODIS have been conducted for turbid inland waters. In this study, we first used synchronous MODIS/Aqua and VIIRS/NPP data (±1 h) collected during 2012-2015 to evaluate the consistency of Rayleigh-corrected reflectance (Rrc) observations over Lake Hongze (the fourth-largest freshwater lake in China), since accurate remote sensing reflectance (Rrs) values cannot be acquired over turbid inland waters. Second, we used recently developed algorithms based on Rrc in the red band to estimate the concentrations of suspended particulate matter (SPM) from MODIS/Aqua and VIIRS/NPP data. Finally, we assessed the consistency of the SPM products derived from MODIS/Aqua and VIIRS/NPP. The results show the following. (1) The differences in Rrc among the green (VIIRS 551 nm and MODIS 555 nm) and red bands (VIIRS 671 nm and MODIS 645 nm) indicate a satisfactory consistency, and the unbiased percentage difference (UPD) is <12%. Meanwhile, the results for the near infrared (NIR) band (MODIS 859 nm and VIIRS 862 nm) indicate relatively large differences (UPD = 21.84%). (2) The satellite-derived SPM products obtained using MODIS/Aqua and VIIRS/NPP have a satisfactory degree of consistency (0-150 mg/L SPM: R2 = 0.81, UPD < 16% and 0-80 mg/L SPM: R2 = 0.85, UPD < 12%, respectively). These results demonstrate that VIIRS/NPP can continue to record the SPM observations initiated by MODIS/Aqua for turbid inland waters and establish environmental datasets over long time periods to support water quality management endeavors.

MALDI In-Source Decay of Protein: The Mechanism of c-Ion Formation

PubMed Central

Takayama, Mitsuo

2016-01-01

The in-source decay (ISD) phenomenon, the fragmentation at an N–Cα bond of a peptide backbone that occurs within several tens of nanoseconds in the ion-source in matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS), is discussed from the standpoints of the discovery and early publications dealing with MALDI-ISD, the formation of c-ions in energy-sudden desorption/ionization methods, the formation of radical species in a MALDI, model construction for ISD, and matrix materials that are suitable for use in MALDI-ISD. The formation of c-ions derived from peptides and proteins in MALDI-ISD can be rationalized by a mechanism involving intermolecular hydrogen transfer, denoted as the “Takayama’s model” by De Pauw’s group (Anal. Chem. 79: 8678–8685, 2007). It should be emphasized that the model for MALDI-ISD was constructed on the basis of X-ray crystallography and scanning probe microscopy (SPM) analyses of matrix crystals, as well as the use of isotopically-labelled peptides. PMID:27162707

Enhancing multi-spot structured illumination microscopy with fluorescence difference

NASA Astrophysics Data System (ADS)

Ward, Edward N.; Torkelsen, Frida H.; Pal, Robert

2018-03-01

Structured illumination microscopy is a super-resolution technique used extensively in biological research. However, this technique is limited in the maximum possible resolution increase. Here we report the results of simulations of a novel enhanced multi-spot structured illumination technique. This method combines the super-resolution technique of difference microscopy with structured illumination deconvolution. Initial results give at minimum a 1.4-fold increase in resolution over conventional structured illumination in a low-noise environment. This new technique also has the potential to be expanded to further enhance axial resolution with three-dimensional difference microscopy. The requirement for precise pattern determination in this technique also led to the development of a new pattern estimation algorithm which proved more efficient and reliable than other methods tested.

Quantifying Forest and Coastal Disturbance from Industrial Mining Using Satellite Time Series Analysis Under Very Cloudy Conditions

NASA Astrophysics Data System (ADS)

Alonzo, M.; Van Den Hoek, J.; Ahmed, N.

2015-12-01

The open-pit Grasberg mine, located in the highlands of Western Papua, Indonesia, and operated by PT Freeport Indonesia (PT-FI), is among the world's largest in terms of copper and gold production. Over the last 27 years, PT-FI has used the Ajkwa River to transport an estimated 1.3 billion tons of tailings from the mine into the so-called Ajkwa Deposition Area (ADA). The ADA is the product of aggradation and lateral expansion of the Ajkwa River into the surrounding lowland rainforest and mangroves, which include species important to the livelihoods of indigenous Papuans. Mine tailings that do not settle in the ADA disperse into the Arafura Sea where they increase levels of suspended particulate matter (SPM) and associated concentrations of dissolved copper. Despite the mine's large-scale operations, ecological impact of mine tailings deposition on the forest and estuarial ecosystems have received minimal formal study. While ground-based inquiries are nearly impossible due to access restrictions, assessment via satellite remote sensing is promising but hindered by extreme cloud cover. In this study, we characterize ridgeline-to-coast environmental impacts along the Ajkwa River, from the Grasberg mine to the Arafura Sea between 1987 and 2014. We use "all available" Landsat TM and ETM+ images collected over this time period to both track pixel-level vegetation disturbance and monitor changes in coastal SPM levels. Existing temporal segmentation algorithms are unable to assess both acute and protracted trajectories of vegetation change due to pervasive cloud cover. In response, we employ robust, piecewise linear regression on noisy vegetation index (NDVI) data in a manner that is relatively insensitive to atmospheric contamination. Using this disturbance detection technique we constructed land cover histories for every pixel, based on 199 image dates, to differentiate processes of vegetation decline, disturbance, and regrowth. Using annual reports from PT-FI, we show that the changing extent and spatial patterns of riparian vegetation disturbance directly correlate with yearly tailings production rates. While the rate of vegetation disturbance decreased after 1998, SPM levels along the Arafura coast increased, suggesting the failure of PT-FI to fully confine tailings to the ADA.

Insulin amyloid structures and their influence on neural cells.

PubMed

Bystrenova, Eva; Bednarikova, Zuzana; Barbalinardo, Marianna; Valle, Francesco; Gazova, Zuzana; Biscarini, Fabio

2018-01-01

Peptide aggregation into oligomers and fibrillar architectures is a hallmark of severe neurodegenerative pathologies, diabetes mellitus or systemic amyloidoses. The polymorphism of amyloid forms and their distribution are both effectors that potentially modulate the disease, thus it is important to understand the molecular basis of protein amyloid disorders through the interaction of the different amyloid forms with neural cells and tissues. Here we explore the effect of amyloid fibrils on the human neuroblastoma (SH-SY5Y) cell line in vitro. We control the kinetic of fibrillization of insulin at low pH and higher temperature. We use a multiscale characterization via fluorescence microscopy and multimodal scanning probe microscopy to correlate the number of cells and their morphology, with the finer details of the insulin deposits. Our results show that insulin aggregates deposited on neuroblastoma cell cultures lead to a progressive modification and decreased number of cells that correlates with the degree of fibrillization. SPM unravels that the aggregates strongly interact with the cell membrane, forming a stiff encase that possibly leads to an increased cell membrane stiffness and deficit in the metabolic exchanges between the cells and their environment. The presence of fibrils does not affect the number of cells at 24h whereas drop down to 60% is observed after 48h of incubation. Copyright © 2017 Elsevier B.V. All rights reserved.

GUIELOA: Adaptive Optics System for the 2.1-m SPM UNAM Telescope

NASA Astrophysics Data System (ADS)

Cuevas, S.; Iriarte, A.; Martínez, L. A.; Garfias, F.; Sánchez, L.; Chapa, O.; Ruelas, R. A.

2004-08-01

GUIELOA is the adaptive optics system project for the 2.1-m SPM telescope. This is a 19 sub-apertures curvature-type system. It corrects 8 Zernike terms. GUIELOA is very similar to PUEO, the CFHT adaptive optics system and compensates the atmospheric turbulence from the R band to the K band. Among the planned applications of GUIELOA are the study of OB binary systems, the detection of close binary stars, and the study of disks, jets and other phenomena associated with young stars.

Plant cell wall characterization using scanning probe microscopy techniques

PubMed Central

Yarbrough, John M; Himmel, Michael E; Ding, Shi-You

2009-01-01

Lignocellulosic biomass is today considered a promising renewable resource for bioenergy production. A combined chemical and biological process is currently under consideration for the conversion of polysaccharides from plant cell wall materials, mainly cellulose and hemicelluloses, to simple sugars that can be fermented to biofuels. Native plant cellulose forms nanometer-scale microfibrils that are embedded in a polymeric network of hemicelluloses, pectins, and lignins; this explains, in part, the recalcitrance of biomass to deconstruction. The chemical and structural characteristics of these plant cell wall constituents remain largely unknown today. Scanning probe microscopy techniques, particularly atomic force microscopy and its application in characterizing plant cell wall structure, are reviewed here. We also further discuss future developments based on scanning probe microscopy techniques that combine linear and nonlinear optical techniques to characterize plant cell wall nanometer-scale structures, specifically apertureless near-field scanning optical microscopy and coherent anti-Stokes Raman scattering microscopy. PMID:19703302

Realistic representation of Bacillus subtilis biofilms architecture using combined microscopy (CLSM, ESEM and FESEM).

PubMed

Bridier, A; Meylheuc, T; Briandet, R

2013-05-01

In this contribution, we used a set of microscopic techniques including confocal laser scanning microscopy (CLSM), environmental scanning electron microscopy (ESEM) and field emission scanning electron microscopy (FESEM) to analyze the three-dimensional spatial arrangement of cells and their surrounding matrix in Bacillus subtilis biofilm. The combination of the different techniques enabled a deeper and realistic deciphering of biofilm architecture by providing the opportunity to overcome the limits of each single technique. Copyright © 2013 Elsevier Ltd. All rights reserved.

Enhancing multi-spot structured illumination microscopy with fluorescence difference

PubMed Central

Torkelsen, Frida H.

2018-01-01

Structured illumination microscopy is a super-resolution technique used extensively in biological research. However, this technique is limited in the maximum possible resolution increase. Here we report the results of simulations of a novel enhanced multi-spot structured illumination technique. This method combines the super-resolution technique of difference microscopy with structured illumination deconvolution. Initial results give at minimum a 1.4-fold increase in resolution over conventional structured illumination in a low-noise environment. This new technique also has the potential to be expanded to further enhance axial resolution with three-dimensional difference microscopy. The requirement for precise pattern determination in this technique also led to the development of a new pattern estimation algorithm which proved more efficient and reliable than other methods tested. PMID:29657751

Applications of microscopy to genetic therapy of cystic fibrosis and other human diseases.

PubMed

Moninger, Thomas O; Nessler, Randy A; Moore, Kenneth C

2006-01-01

Gene therapy has become an extremely important and active field of biomedical research. Microscopy is an integral component of this effort. This chapter presents an overview of imaging techniques used in our facility in support of cystic fibrosis gene therapy research. Instrumentation used in these studies includes light and confocal microscopy, transmission electron microscopy, and scanning electron microscopy. Techniques outlined include negative staining, cryo-electron microscopy, three-dimentional reconstruction, enzyme cytochemistry, immunocytochemistry, and fluorescence imaging.

Correlative Super-Resolution Microscopy: New Dimensions and New Opportunities.

PubMed

Hauser, Meghan; Wojcik, Michal; Kim, Doory; Mahmoudi, Morteza; Li, Wan; Xu, Ke

2017-06-14

Correlative microscopy, the integration of two or more microscopy techniques performed on the same sample, produces results that emphasize the strengths of each technique while offsetting their individual weaknesses. Light microscopy has historically been a central method in correlative microscopy due to its widespread availability, compatibility with hydrated and live biological samples, and excellent molecular specificity through fluorescence labeling. However, conventional light microscopy can only achieve a resolution of ∼300 nm, undercutting its advantages in correlations with higher-resolution methods. The rise of super-resolution microscopy (SRM) over the past decade has drastically improved the resolution of light microscopy to ∼10 nm, thus creating exciting new opportunities and challenges for correlative microscopy. Here we review how these challenges are addressed to effectively correlate SRM with other microscopy techniques, including light microscopy, electron microscopy, cryomicroscopy, atomic force microscopy, and various forms of spectroscopy. Though we emphasize biological studies, we also discuss the application of correlative SRM to materials characterization and single-molecule reactions. Finally, we point out current limitations and discuss possible future improvements and advances. We thus demonstrate how a correlative approach adds new dimensions of information and provides new opportunities in the fast-growing field of SRM.

Synthesis of single-molecule nanocars.

PubMed

Vives, Guillaume; Tour, James M

2009-03-17

The drive to miniaturize devices has led to a variety of molecular machines inspired by macroscopic counterparts such as molecular motors, switches, shuttles, turnstiles, barrows, elevators, and nanovehicles. Such nanomachines are designed for controlled mechanical motion and the transport of nanocargo. As researchers miniaturize devices, they can consider two complementary approaches: (1) the "top-down" approach, which reduces the size of macroscopic objects to reach an equivalent microscopic entity using photolithography and related techniques and (2) the "bottom-up" approach, which builds functional microscopic or nanoscopic entities from molecular building blocks. The top-down approach, extensively used by the semiconductor industry, is nearing its scaling limits. On the other hand, the bottom-up approach takes advantage of the self-assembly of smaller molecules into larger networks by exploiting typically weak molecular interactions. But self-assembly alone will not permit complex assembly. Using nanomachines, we hope to eventually consider complex, enzyme-like directed assembly. With that ultimate goal, we are currently exploring the control of nanomachines that would provide a basis for the future bottom-up construction of complex systems. This Account describes the synthesis of a class of molecular machines that resemble macroscopic vehicles. We designed these so-called nanocars for study at the single-molecule level by scanning probe microscopy (SPM). The vehicles have a chassis connected to wheel-terminated axles and convert energy inputs such as heat, electric fields, or light into controlled motion on a surface, ultimately leading to transport of nanocargo. At first, we used C(60) fullerenes as wheels, which allowed the demonstration of a directional rolling mechanism of a nanocar on a gold surface by STM. However, because of the low solubility of the fullerene nanocars and the incompatibility of fullerenes with photochemical processes, we developed new p-carborane- and ruthenium-based wheels with greater solubility in organic solvents. Although fullerene wheels must be attached in the final synthetic step, p-carborane- and ruthenium-based wheels do not inhibit organometallic coupling reactions, which allows a more convergent synthesis of molecular machines. We also prepared functional nanotrucks for the transport of atoms and molecules, as well as self-assembling nanocars and nanotrains. Although engineering challenges such as movement over long distance and non-atomically flat surfaces remain, the greatest current research challenge is imaging. The detailed study of nanocars requires complementary single molecule imaging techniques such as STM, AFM, TEM, or single-molecule fluorescence microscopy. Further developments in engineering and synthesis could lead to enzyme-like manipulation and assembly of atoms and small molecules in nonbiological environments.

Use of Zn isotopes as a probe of anthropogenic contamination and biogeochemical processes in the Seine River, France

NASA Astrophysics Data System (ADS)

Chen, J.; Gaillardet, J.; Louvat, P.; Birck, J.

2009-05-01

Metal contamination is a major issue of human impact on the aqueous environment. River water is particularly susceptible to contamination for both dissolved and particulate loads, displaying a major challenge in understanding the dominant sources and pathways of metals in polluted drainage basins. Recent improvements in mass spectrometry allow isotopic measurements of "non-traditional" metals (Zn, Cu, Fe, etc.), making their isotopes a new potential device to investigate contamination of metals under dissolved and particulate forms in rivers. We focus here on Zn isotope geochemistry in the largely anthropized Seine River (France). A new protocol of two-column separation of Zn from dilute aqueous solution has been developed and proven to be reproducible and satisfactory for accurate measurement of Zn isotopic ratios in water samples by MC-ICP-MS (2σ = 0.04‰). Preliminary results show a total variation of 0.65‰ for δ66Zn in dissolved phases of the Seine basin, and a light isotope enrichment in anthropogenic sources compared to other water samples. The determined conservative behavior of Zn in river water makes its isotopes an effective probe of anthropogenic contamination. The natural and anthropogenic inputs were clearly identified and calculated based on Zn isotope compositions for dissolved loads. Suspended particular matters (SPM) display different Zn isotope compositions compared to dissolved loads, with a total δ66Zn variation of 0.22‰. Zn concentrations and its isotope compositions in SPM reveal inverse relationships as function of the distance from the headwater and the SPM content for geographical and temporal samples, respectively. The δ66Zn data in SPM are interpreted as reflecting the mixture of natural and anthropogenic particles. The correlation between dissolved and particulate δ66Zn shows that adsorption processes are not the dominant process making Zn enrichment in SPM. We report here for the first time systematic δ66Zn data in waters of a whole river basin, showing Zn isotopes a powerful probe to trace contamination sources and biogeochemical processes in hydrologic systems.

A sequential vesicle pool model with a single release sensor and a Ca(2+)-dependent priming catalyst effectively explains Ca(2+)-dependent properties of neurosecretion.

PubMed

Walter, Alexander M; Pinheiro, Paulo S; Verhage, Matthijs; Sørensen, Jakob B

2013-01-01

Neurotransmitter release depends on the fusion of secretory vesicles with the plasma membrane and the release of their contents. The final fusion step displays higher-order Ca(2+) dependence, but also upstream steps depend on Ca(2+). After deletion of the Ca(2+) sensor for fast release - synaptotagmin-1 - slower Ca(2+)-dependent release components persist. These findings have provoked working models involving parallel releasable vesicle pools (Parallel Pool Models, PPM) driven by alternative Ca(2+) sensors for release, but no slow release sensor acting on a parallel vesicle pool has been identified. We here propose a Sequential Pool Model (SPM), assuming a novel Ca(2+)-dependent action: a Ca(2+)-dependent catalyst that accelerates both forward and reverse priming reactions. While both models account for fast fusion from the Readily-Releasable Pool (RRP) under control of synaptotagmin-1, the origins of slow release differ. In the SPM the slow release component is attributed to the Ca(2+)-dependent refilling of the RRP from a Non-Releasable upstream Pool (NRP), whereas the PPM attributes slow release to a separate slowly-releasable vesicle pool. Using numerical integration we compared model predictions to data from mouse chromaffin cells. Like the PPM, the SPM explains biphasic release, Ca(2+)-dependence and pool sizes in mouse chromaffin cells. In addition, the SPM accounts for the rapid recovery of the fast component after strong stimulation, where the PPM fails. The SPM also predicts the simultaneous changes in release rate and amplitude seen when mutating the SNARE-complex. Finally, it can account for the loss of fast- and the persistence of slow release in the synaptotagmin-1 knockout by assuming that the RRP is depleted, leading to slow and Ca(2+)-dependent fusion from the NRP. We conclude that the elusive 'alternative Ca(2+) sensor' for slow release might be the upstream priming catalyst, and that a sequential model effectively explains Ca(2+)-dependent properties of secretion without assuming parallel pools or sensors.

Distribution and geochemical composition of suspended particulate material in the shallow embayment of northern Thermaikos Gulf, Greece

NASA Astrophysics Data System (ADS)

Tsompanoglou, K.; Anagnostou, Ch.; Krasakopoulou, E.; Pagou, K.; Karageorgis, A. P.; Pavlidou, A.; Albanakis, K.; Tsirambides, A.

2017-07-01

The distribution and the chemical composition of Suspended Particulate Matter (SPM), in the northern Thermaikos Gulf, were studied during an annual experiment, carried out from June 2004 to June 2005. Water samples were collected at three depths (1 m below surface, 10 m depth, and 2 m above bottom) and filtered to obtain SPM, particulate organic carbon (POC), total particulate nitrogen (PNtot) and particulate phosphorus (PP) concentrations. SPM and POC concentrations exhibited strong spatial and temporal variations, related to the different environmental characteristics in the study area such as river network, biological productivity, anthropogenic interferences, wind regime, and resuspension of the bottom sediments. The highest SPM concentrations were recorded at the surface (mean = 1.45 ± 0.75 mg/l, maximum value = 11.60 mg/l) and close to the bottom (mean = 1.49 ± 0.67 mg/l, maximum value = 11.72 mg/l), creating surface and bottom nepheloid layers (SNL and BNL), respectively. The maximum values were recorded close to the river mouths; the rivers are identified as the major sources of SPM. The Axios and Aliakmon rivers supplied the gulf with particulate matter, during the entire sampling period. Chemical analysis has revealed the significant correlation among the elements Al, Si, Fe, Ti, K, V, Mg and Ba suggesting the presence of terrigenous aluminosilicate minerals. Silica and Ca have terrigenous origin, but also come from autochthonous biogenic fraction. Chromium, Ni and Co, are of natural origin and derived from mafic and ultramafic rocks of the Axios and Aliakmon watersheds. Copper and Zn are correlated with each other and their distributions follow that of POC; these two metals are derived from partially treated domestic and industrial effluents. The vertical distribution of organic matter implies increased primary production within the upper layer of the water column. Phosphorus is present mainly in an organic form. During the sampling period, the water column was well-oxygenated. Early diagenesis only affected the concentrations of Mn and to a lesser extent Fe in the recently deposited seabed sediment.

Stable carbon isotope ratios of archaeal GDGTs in the marine water column and surface sediments

NASA Astrophysics Data System (ADS)

Pearson, A.; Hurley, S.; Close, H. G.; Jasper, C. E.

2016-12-01

Archaeal glycerol dibiphytanyl glycerol tetraether (GDGT) lipids are ubiquitous throughout the marine environment and are preserved in sediments and sedimentary rocks on million-year timescales. Variations in the number of ring-containing GDGT isomers in sediments correlate with differences in overlying sea surface temperatures, a relationship formalized in the TEX86 paleotemperature proxy. Ammonia-oxidizing Thaumarchaeota are believed to be the major sources of these GDGTs, implying that the greatest production and export of GDGTs from the water column should be associated with the maximum expression of ammonia monooxygenase (amoA) genes and maximum number of thaumarchaeal cells, both of which occur in the subsurface NO2- maximum near a depth of ca. 80-250 m. To examine the relationship between production and export of GDGTs from the water column, we measured the concentrations and δ13C values of GDGTs in suspended particulate matter (SPM) of the western South Atlantic Ocean and compared them to values from pure thaumarchaeal cultures and from available sediment core-tops from other locations. Thaumarchaeota are believed to fix the majority of their carbon directly from dissolved inorganic carbon (DIC). However, both the SPM and core-top δ13C values in some cases are moderately more 13C-depleted than would be predicted based on the 13C content of local DIC and the previously-published biosynthetic isotope fractionation (ɛ). This indicates that the average metabolism of the planktonic archaeal community either is mixotrophic (≥ 25% organic carbon assimilation) or that the published ɛ value for the model organism Nitrosopumilus maritimus may not be representative of the total autotrophic community. In addition to this offset, δ13C values of GDGTs in SPM inversely mirror DIC profiles, with lowest values in the nitrite maximum and higher values in the deeper water column, similar to the overall trends for bulk SPM. Finally, while individual GDGTs in SPM samples have similar δ13C values, in many sediments measured to date, the isotopic composition of individual GDGTs differs. This implies that multiple sources of GDGTs are required to explain core-top 13C distributions, especially on continental margins.

Magnetic fingerprint of the sediment load in a meander bend section of the Seine River (France)

NASA Astrophysics Data System (ADS)

Kayvantash, D.; Cojan, I.; Kissel, C.; Franke, C.

2017-06-01

This study aims to evaluate the potential of magnetic methods to determine the composition of the sediment load in a cross section of an unmanaged meander in the upstream stretch of the Seine River (Marnay-sur-Seine). Suspended particulate matter (SPM) was collected based on a regular sampling scheme along a cross section of the river, at two different depth levels: during a low-water stage (May 2014) and a high-water stage (February 2015). Riverbed sediments (RBS) were collected during the low-water stage and supplementary samples were taken from the outer and inner banks. Magnetic properties of the dry bulk SPM and sieved RBS and bank sediments were analysed. After characterizing the main magnetic carrier as magnetite, hysteresis parameters were measured, giving access to the grain size and the concentration of these magnetite particles. The results combined with sedimentary grain size data were compared to the three-dimensional velocity profile of the river flow. In the RBS where the magnetic grain size is rather uniform, the concentration of magnetite is inversely proportional to the mean grain size of the total sediment indicating that magnetite is strongly associated with the fine sedimentary fraction. The same pattern is observed in the samples from the outer and inner banks. During the low-water stage, the uniformly fine SPM grain size distribution characterizes the wash load. The magnetic fraction is also relatively fine (within the pseudo single domain range) with concentration similar to that of the fine RBS fraction. During the high-water stage, SPM samples correspond to mixtures of wash load and resuspended sediment from the bedload and riverbanks. Here, the grain size distribution is heterogeneous across the section showing coarser particles compared to those in the low-water stage and more varying magnetite concentrations while the magnetic grain size is like that of the low-water stage. The magnetite concentration in the high-water SPM can be modelled based on a mixing of the magnetite concentrations of the different grain size fractions, thus quantifying the impact of resuspension in the cross section.

A Sequential Vesicle Pool Model with a Single Release Sensor and a Ca2+-Dependent Priming Catalyst Effectively Explains Ca2+-Dependent Properties of Neurosecretion

PubMed Central

Walter, Alexander M.; Pinheiro, Paulo S.; Verhage, Matthijs; Sørensen, Jakob B.

2013-01-01

Neurotransmitter release depends on the fusion of secretory vesicles with the plasma membrane and the release of their contents. The final fusion step displays higher-order Ca2+ dependence, but also upstream steps depend on Ca2+. After deletion of the Ca2+ sensor for fast release – synaptotagmin-1 – slower Ca2+-dependent release components persist. These findings have provoked working models involving parallel releasable vesicle pools (Parallel Pool Models, PPM) driven by alternative Ca2+ sensors for release, but no slow release sensor acting on a parallel vesicle pool has been identified. We here propose a Sequential Pool Model (SPM), assuming a novel Ca2+-dependent action: a Ca2+-dependent catalyst that accelerates both forward and reverse priming reactions. While both models account for fast fusion from the Readily-Releasable Pool (RRP) under control of synaptotagmin-1, the origins of slow release differ. In the SPM the slow release component is attributed to the Ca2+-dependent refilling of the RRP from a Non-Releasable upstream Pool (NRP), whereas the PPM attributes slow release to a separate slowly-releasable vesicle pool. Using numerical integration we compared model predictions to data from mouse chromaffin cells. Like the PPM, the SPM explains biphasic release, Ca2+-dependence and pool sizes in mouse chromaffin cells. In addition, the SPM accounts for the rapid recovery of the fast component after strong stimulation, where the PPM fails. The SPM also predicts the simultaneous changes in release rate and amplitude seen when mutating the SNARE-complex. Finally, it can account for the loss of fast- and the persistence of slow release in the synaptotagmin-1 knockout by assuming that the RRP is depleted, leading to slow and Ca2+-dependent fusion from the NRP. We conclude that the elusive ‘alternative Ca2+ sensor’ for slow release might be the upstream priming catalyst, and that a sequential model effectively explains Ca2+-dependent properties of secretion without assuming parallel pools or sensors. PMID:24339761

Topography of brain glucose hypometabolism and epileptic network in glucose transporter 1 deficiency.

PubMed

Akman, Cigdem Inan; Provenzano, Frank; Wang, Dong; Engelstad, Kristin; Hinton, Veronica; Yu, Julia; Tikofsky, Ronald; Ichese, Masonari; De Vivo, Darryl C

2015-02-01

(18)F fluorodeoxyglucose positron emission tomography ((18)F FDG-PET) facilitates examination of glucose metabolism. Previously, we described regional cerebral glucose hypometabolism using (18)F FDG-PET in patients with Glucose transporter 1 Deficiency Syndrome (Glut1 DS). We now expand this observation in Glut1 DS using quantitative image analysis to identify the epileptic network based on the regional distribution of glucose hypometabolism. (18)F FDG-PET scans of 16 Glut1 DS patients and 7 healthy participants were examined using Statistical parametric Mapping (SPM). Summed images were preprocessed for statistical analysis using MATLAB 7.1 and SPM 2 software. Region of interest (ROI) analysis was performed to validate SPM results. Visual analysis of the (18)F FDG-PET images demonstrated prominent regional glucose hypometabolism in the thalamus, neocortical regions and cerebellum bilaterally. Group comparison using SPM analysis confirmed that the regional distribution of glucose hypo-metabolism was present in thalamus, cerebellum, temporal cortex and central lobule. Two mildly affected patients without epilepsy had hypometabolism in cerebellum, inferior frontal cortex, and temporal lobe, but not thalamus. Glucose hypometabolism did not correlate with age at the time of PET imaging, head circumference, CSF glucose concentration at the time of diagnosis, RBC glucose uptake, or CNS score. Quantitative analysis of (18)F FDG-PET imaging in Glut1 DS patients confirmed that hypometabolism was present symmetrically in thalamus, cerebellum, frontal and temporal cortex. The hypometabolism in thalamus correlated with the clinical history of epilepsy. Copyright © 2014. Published by Elsevier B.V.

Tidal cycles of total particulate mercury in the Jade Bay, lower Saxonian Wadden Sea, southern North Sea.

PubMed

Jin, Huafang; Liebezeit, Gerd

2013-01-01

In this study, we evaluate the nature of the relationship between particulate matter and total mercury concentrations. For this purpose, we estimate both of the two values in water column over 12-h tidal cycles of the Jade Bay, southern North Sea. Total particulate mercury in 250 mL water samples was determined by oxygen combustion-gold amalgamation. Mercury contents varied from 63 to 259 ng/g suspended particulate matter (SPM) or 3.5-52.8 ng/L in surface waters. Total particulate mercury content (THg(p)) was positively correlated with (SPM), indicating that mercury in tidal waters is mostly associated with (SPM), and that tidal variations of total particulate mercury are mainly due to changes in (SPM) content throughout the tidal cycle. Maximum values for THg(p) were observed during mid-flood and mid-ebb, while the lowest values were determined at low tide and high tide. These data suggest that there are no mercury point sources in the Jade Bay. Moreover, the THg(p) content at low tide and high tide were significantly lower than the values recorded in the bottom sediment of the sampling site (>200 ng/g DW), while THg(p) content during the mid-flood and mid-ebb were comparable to the THg content in the surface bottom sediments. Therefore, changes in THg(p) content in the water column due to tidal forcing may have resulted from re-suspension of underlying surface sediments with relatively high mercury content.

Extending Inferential Group Analysis in Type 2 Diabetic Patients with Multivariate GLM Implemented in SPM8.

PubMed

Ferreira, Fábio S; Pereira, João M S; Duarte, João V; Castelo-Branco, Miguel

2017-01-01

Although voxel based morphometry studies are still the standard for analyzing brain structure, their dependence on massive univariate inferential methods is a limiting factor. A better understanding of brain pathologies can be achieved by applying inferential multivariate methods, which allow the study of multiple dependent variables, e.g. different imaging modalities of the same subject. Given the widespread use of SPM software in the brain imaging community, the main aim of this work is the implementation of massive multivariate inferential analysis as a toolbox in this software package. applied to the use of T1 and T2 structural data from diabetic patients and controls. This implementation was compared with the traditional ANCOVA in SPM and a similar multivariate GLM toolbox (MRM). We implemented the new toolbox and tested it by investigating brain alterations on a cohort of twenty-eight type 2 diabetes patients and twenty-six matched healthy controls, using information from both T1 and T2 weighted structural MRI scans, both separately - using standard univariate VBM - and simultaneously, with multivariate analyses. Univariate VBM replicated predominantly bilateral changes in basal ganglia and insular regions in type 2 diabetes patients. On the other hand, multivariate analyses replicated key findings of univariate results, while also revealing the thalami as additional foci of pathology. While the presented algorithm must be further optimized, the proposed toolbox is the first implementation of multivariate statistics in SPM8 as a user-friendly toolbox, which shows great potential and is ready to be validated in other clinical cohorts and modalities.

Aerosol optical properties measurements by a CAPS single scattering albedo monitor: Comparisons between summer and winter in Beijing, China

NASA Astrophysics Data System (ADS)

Han, Tingting; Xu, Weiqi; Li, Jie; Freedman, Andrew; Zhao, Jian; Wang, Qingqing; Chen, Chen; Zhang, Yingjie; Wang, Zifa; Fu, Pingqing; Liu, Xingang; Sun, Yele

2017-02-01

Aerosol optical properties were measured in Beijing in summer and winter using a state-of-the-art cavity attenuated phase shift single scattering albedo monitor (CAPS PMssa) along with aerosol composition measurements by aerosol mass spectrometers and aethalometers. The SSA directly measured by the CAPS PMssa showed overall agreements with those derived from colocated measurements. However, substantial differences were observed during periods with low SSA values in both summer and winter, suggesting that interpretation of low SSA values needs to be cautious. The average (±σ) extinction coefficient (bext) and absorption coefficient (bap) were 336 (±343) Mm-1 and 44 (±41) Mm-1, respectively, during wintertime, which were approximately twice those observed in summer, while the average SSA was relatively similar, 0.86 (±0.06) and 0.85 (±0.04) in summer and winter, respectively. Further analysis showed that the variations in SSA can be approximately parameterized as a function of mass fraction of secondary particulate matter (fSPM), which is SSA = 0.74 + 0.19 × fSPM (fSPM > 0.3, r2 = 0.85). The contributions of aerosol species to extinction coefficients during the two seasons were also estimated. Our results showed that the light extinction was dominantly contributed by ammonium sulfate (30%) and secondary organic aerosol (22%) in summer, while organic aerosol was the largest contributor (51%) in winter. Consistently, SPM played the major role in visibility degradation in both seasons by contributing 70% of the total extinction.

An empirical comparison of SPM preprocessing parameters to the analysis of fMRI data.

PubMed

Della-Maggiore, Valeria; Chau, Wilkin; Peres-Neto, Pedro R; McIntosh, Anthony R

2002-09-01

We present the results from two sets of Monte Carlo simulations aimed at evaluating the robustness of some preprocessing parameters of SPM99 for the analysis of functional magnetic resonance imaging (fMRI). Statistical robustness was estimated by implementing parametric and nonparametric simulation approaches based on the images obtained from an event-related fMRI experiment. Simulated datasets were tested for combinations of the following parameters: basis function, global scaling, low-pass filter, high-pass filter and autoregressive modeling of serial autocorrelation. Based on single-subject SPM analysis, we derived the following conclusions that may serve as a guide for initial analysis of fMRI data using SPM99: (1) The canonical hemodynamic response function is a more reliable basis function to model the fMRI time series than HRF with time derivative. (2) Global scaling should be avoided since it may significantly decrease the power depending on the experimental design. (3) The use of a high-pass filter may be beneficial for event-related designs with fixed interstimulus intervals. (4) When dealing with fMRI time series with short interstimulus intervals (<8 s), the use of first-order autoregressive model is recommended over a low-pass filter (HRF) because it reduces the risk of inferential bias while providing a relatively good power. For datasets with interstimulus intervals longer than 8 seconds, temporal smoothing is not recommended since it decreases power. While the generalizability of our results may be limited, the methods we employed can be easily implemented by other scientists to determine the best parameter combination to analyze their data.

Role of Ribonucleotide Reductase in Bacillus subtilis Stress-Associated Mutagenesis.

PubMed

Castro-Cerritos, Karla Viridiana; Yasbin, Ronald E; Robleto, Eduardo A; Pedraza-Reyes, Mario

2017-02-15

The Gram-positive microorganism Bacillus subtilis relies on a single class Ib ribonucleotide reductase (RNR) to generate 2'-deoxyribonucleotides (dNDPs) for DNA replication and repair. In this work, we investigated the influence of RNR levels on B. subtilis stationary-phase-associated mutagenesis (SPM). Since RNR is essential in this bacterium, we engineered a conditional mutant of strain B. subtilis YB955 (hisC952 metB5 leu427) in which expression of the nrdEF operon was modulated by isopropyl-β-d-thiogalactopyranoside (IPTG). Moreover, genetic inactivation of ytcG, predicted to encode a repressor (NrdR) of nrdEF in this strain, dramatically increased the expression levels of a transcriptional nrdE-lacZ fusion. The frequencies of mutations conferring amino acid prototrophy in three genes were measured in cultures under conditions that repressed or induced RNR-encoding genes. The results revealed that RNR was necessary for SPM and overexpression of nrdEF promoted growth-dependent mutagenesis and SPM. We also found that nrdEF expression was induced by H 2 O 2 and such induction was dependent on the master regulator PerR. These observations strongly suggest that the metabolic conditions operating in starved B. subtilis cells increase the levels of RNR, which have a direct impact on SPM. Results presented in this study support the concept that the adverse metabolic conditions prevailing in nutritionally stressed bacteria activate an oxidative stress response that disturbs ribonucleotide reductase (RNR) levels. Such an alteration of RNR levels promotes mutagenic events that allow Bacillus subtilis to escape from growth-limited conditions. Copyright © 2017 American Society for Microbiology.

Multi-matrix quantification and risk assessment of pesticides in the longest river of the Iberian peninsula.

PubMed

Cruzeiro, Catarina; Pardal, Miguel Ângelo; Rodrigues-Oliveira, Nádia; Castro, L Filipe C; Rocha, Eduardo; Rocha, Maria João

2016-12-01

The distribution of pesticides in dissolved aqueous phase (DAP), suspended particulate matter (SPM) and Scrobicularia plana soft tissues from the Tagus River estuary was determined to evaluate the chemicals pollution status and their hazard potential in this area. Samples were collected in 6 campaigns (December 2012-October 2013), from 3 strategical sites, and analysed via different extraction procedures followed by gas chromatography tandem mass spectrometry (GC-MS/MS) determination. The contamination profile among matrices (DAP, SPM, and soft tissue from bivalves (STB)) was marked by average concentrations of 345ng/L, 0.51mg/kg, and 0.02mg/kg, respectively, with several samples above the 2013/39/EU Directive of environmental quality standards (EQS); no differences were observed between sex. A wider range of pesticides was present in STB (n=53) than in SPM (n=36) and DAP (n=19) matrices. Sediment-water partition coefficient, bioaccumulation factor in both DAP and SPM fraction were estimated ranging between 2.5 and 4.4 and 0.008-2799, respectively. The spatial distribution of most pesticides and physicochemical parameters were consistent, indicating a pollution pattern primarily near the Trancão River mouth. Due to the presence of the target compounds, calculated risk quotients pointed out potential hazards for aquatic organisms, mainly to invertebrates. The estimated average daily intake, theoretical maximum daily intake, and hazard quotient of the studied pesticides-via bivalve ingestion-indicated no risk for human health, although it is important to note possible biomagnification processes that may happen along the estuarine food-chain. Copyright © 2016 Elsevier B.V. All rights reserved.

Chemical determination of particulate nitrogen in San Francisco Bay. Nitrogen: chlorophyll a ratios in plankton

USGS Publications Warehouse

Hager, S.W.; Harmon, D.D.; Alpine, A.E.

1984-01-01

Particulate nitrogen (PN) and chlorophyll a (Chla) were measured in the northern reach of San Francisco Bay throughout 1980. The PN values were calculated as the differences between unfiltered and filtered (0??4 ??m) samples analyzed using the UV-catalyzed peroxide digestion method. The Chla values were measured spectrophotometrically, with corrections made for phaeopigments. The plot of all PN Chla data was found to be non-linear, and the concentration of suspended particulate matter (SPM) was found to be the best selector for linear subsets of the data. The best-fit slopes of PN Chla plots, as determined by linear regression (model II), were interpreted to be the N: Chla ratios of phytoplankton. The Y-intercepts of the regression lines were considered to represent easily-oxidizable detrital nitrogen (EDN). In clear water ( < 10 mg l-1 SPM), the N: Chla ratio was 1??07 ??g-at N per ??g Chla. It decreased to 0??60 in the 10-18 mg l-1 range and averaged 0??31 in the remaining four ranges (18-35, 35-65, 65-155, and 155-470 mg l-1). The EDN values were less than 1 ??g-at N l-1 in the clear water and increased monotonically to almost 12 ??g-at N l-1 in the highest SPM range. The N: Chla ratios for the four highest SPM ranges agree well with data for phytoplankton in light-limited cultures. In these ranges, phytoplankton-N averaged only 20% of the PN, while EDN averaged 39% and refractory-N 41%. ?? 1984.

Polyamines and ethylene interact in rice grains in response to soil drying during grain filling.

PubMed

Chen, Tingting; Xu, Yunji; Wang, Jingchao; Wang, Zhiqin; Yang, Jianchang; Zhang, Jianhua

2013-05-01

This study tested the hypothesis that the interaction between polyamines and ethylene may mediate the effects of soil drying on grain filling of rice (Oryza sativa L.). Two rice cultivars were pot grown. Three treatments, well-watered, moderate soil drying (MD), and severe soil drying (SD), were imposed from 8 d post-anthesis until maturity. The endosperm cell division rate, grain-filling rate, and grain weight of earlier flowering superior spikelets showed no significant differences among the three treatments. However, those of the later flowering inferior spikelets were significantly increased under MD and significantly reduced under SD when compared with those which were well watered. The two cultivars showed the same tendencies. MD increased the contents of free spermidine (Spd) and free spermine (Spm), the activities of S-adenosyl-L-methionine decarboxylase and Spd synthase, and expression levels of polyamine synthesis genes, and decreased the ethylene evolution rate, the contents of 1-aminocylopropane-1-carboxylic acid (ACC) and hydrogen peroxide, the activities of ACC synthase, ACC oxidase, and polyamine oxidase, and the expression levels of ethylene synthesis genes in inferior spikelets. SD exhibited the opposite effects. Application of Spd, Spm, or an inhibitor of ethylene synthesis to rice panicles significantly reduced ethylene and ACC levels, but significantly increased Spd and Spm contents, grain-filling rate, and grain weight of inferior spikelets. The results were reversed when ACC or an inhibitor of Spd and Spm synthesis was applied. The results suggest that a potential metabolic interaction between polyamines and ethylene biosynthesis responds to soil drying and mediates the grain filling of inferior spikelets in rice.

A Localized Complex of Two Protein Oligomers Controls the Orientation of Cell Polarity

PubMed Central

Lasker, Keren; Ahrens, Daniel G.; Eckart, Michael R.

2017-01-01

ABSTRACT Signaling hubs at bacterial cell poles establish cell polarity in the absence of membrane-bound compartments. In the asymmetrically dividing bacterium Caulobacter crescentus, cell polarity stems from the cell cycle-regulated localization and turnover of signaling protein complexes in these hubs, and yet the mechanisms that establish the identity of the two cell poles have not been established. Here, we recapitulate the tripartite assembly of a cell fate signaling complex that forms during the G1-S transition. Using in vivo and in vitro analyses of dynamic polar protein complex formation, we show that a polymeric cell polarity protein, SpmX, serves as a direct bridge between the PopZ polymeric network and the cell fate-directing DivJ histidine kinase. We demonstrate the direct binding between these three proteins and show that a polar microdomain spontaneously assembles when the three proteins are coexpressed heterologously in an Escherichia coli test system. The relative copy numbers of these proteins are essential for complex formation, as overexpression of SpmX in Caulobacter reorganizes the polarity of the cell, generating ectopic cell poles containing PopZ and DivJ. Hierarchical formation of higher-order SpmX oligomers nucleates new PopZ microdomain assemblies at the incipient lateral cell poles, driving localized outgrowth. By comparison to self-assembling protein networks and polar cell growth mechanisms in other bacterial species, we suggest that the cooligomeric PopZ-SpmX protein complex in Caulobacter illustrates a paradigm for coupling cell cycle progression to the controlled geometry of cell pole establishment. PMID:28246363

Accurate discrimination of Alzheimer's disease from other dementia and/or normal subjects using SPECT specific volume analysis

NASA Astrophysics Data System (ADS)

Iyatomi, Hitoshi; Hashimoto, Jun; Yoshii, Fumuhito; Kazama, Toshiki; Kawada, Shuichi; Imai, Yutaka

2014-03-01

Discrimination between Alzheimer's disease and other dementia is clinically significant, however it is often difficult. In this study, we developed classification models among Alzheimer's disease (AD), other dementia (OD) and/or normal subjects (NC) using patient factors and indices obtained by brain perfusion SPECT. SPECT is commonly used to assess cerebral blood flow (CBF) and allows the evaluation of the severity of hypoperfusion by introducing statistical parametric mapping (SPM). We investigated a total of 150 cases (50 cases each for AD, OD, and NC) from Tokai University Hospital, Japan. In each case, we obtained a total of 127 candidate parameters from: (A) 2 patient factors (age and sex), (B) 12 CBF parameters and 113 SPM parameters including (C) 3 from specific volume analysis (SVA), and (D) 110 from voxel-based analysis stereotactic extraction estimation (vbSEE). We built linear classifiers with a statistical stepwise feature selection and evaluated the performance with the leave-one-out cross validation strategy. Our classifiers achieved very high classification performances with reasonable number of selected parameters. In the most significant discrimination in clinical, namely those of AD from OD, our classifier achieved both sensitivity (SE) and specificity (SP) of 96%. In a similar way, our classifiers achieved a SE of 90% and a SP of 98% in AD from NC, as well as a SE of 88% and a SP of 86% in AD from OD and NC cases. Introducing SPM indices such as SVA and vbSEE, classification performances improved around 7-15%. We confirmed that these SPM factors are quite important for diagnosing Alzheimer's disease.

Extending Inferential Group Analysis in Type 2 Diabetic Patients with Multivariate GLM Implemented in SPM8

PubMed Central

Ferreira, Fábio S.; Pereira, João M.S.; Duarte, João V.; Castelo-Branco, Miguel

2017-01-01

Background: Although voxel based morphometry studies are still the standard for analyzing brain structure, their dependence on massive univariate inferential methods is a limiting factor. A better understanding of brain pathologies can be achieved by applying inferential multivariate methods, which allow the study of multiple dependent variables, e.g. different imaging modalities of the same subject. Objective: Given the widespread use of SPM software in the brain imaging community, the main aim of this work is the implementation of massive multivariate inferential analysis as a toolbox in this software package. applied to the use of T1 and T2 structural data from diabetic patients and controls. This implementation was compared with the traditional ANCOVA in SPM and a similar multivariate GLM toolbox (MRM). Method: We implemented the new toolbox and tested it by investigating brain alterations on a cohort of twenty-eight type 2 diabetes patients and twenty-six matched healthy controls, using information from both T1 and T2 weighted structural MRI scans, both separately – using standard univariate VBM - and simultaneously, with multivariate analyses. Results: Univariate VBM replicated predominantly bilateral changes in basal ganglia and insular regions in type 2 diabetes patients. On the other hand, multivariate analyses replicated key findings of univariate results, while also revealing the thalami as additional foci of pathology. Conclusion: While the presented algorithm must be further optimized, the proposed toolbox is the first implementation of multivariate statistics in SPM8 as a user-friendly toolbox, which shows great potential and is ready to be validated in other clinical cohorts and modalities. PMID:28761571

Legacy and emerging halogenated flame retardants in the middle and lower stream of the Yellow River.

PubMed

Su, Xianfa; Li, Qilu; Feng, Jinglan; Guo, Liya; Sun, Jianhui

2017-12-01

Halogenated flame retardants (HFRs), mainly encompassing polybrominated diphenylethers (PBDEs), dechlorane plus (DP) and emerging bromine flame retardants (EBFRs), are widely employed nowadays in daily lives. However, limited knowledge has been gained to date on the concentrations and distributions of HFRs in particular within certain regions. In the present study, legacy and emerging HFRs were systematically measured in suspended particle matter (SPM) and sediments collected in 2014 from the middle and lower reach of the Yellow River in Henan province. The total concentrations of HFRs in SPM among the three seasons were 42.2±91.2ngg -1 , which was far higher than the corresponding values of HFRs in sediments (1.82±2.94ngg -1 ). In this study, PBDEs, DP and EBFRs in sediment almost exhibited relatively lower levels as compared to those found in other studies, where the limited usage of HFRs in the middle and lower stream of the Yellow River was probably the major impact factor. EBFR was the predominate pollutant from SPM and sediments in most of the sampling sites, suggesting that EBFRs were widely used nowadays as substitute materials of 'old' FRs. The mean concentration values of DBDPE/BDE-209 in SPM and sediments were apparently higher than those of previous studies. Furthermore, it is interesting to reveal that herein almost all of the HFR concentrations were unrelated to the population and GDP, which might be attributed to the characteristics of 'elevated stream' of the Yellow River as well as the complex river systems in Henan province. Copyright © 2017 Elsevier B.V. All rights reserved.

An integrated evaluation of some faecal indicator bacteria (FIB) and chemical markers as potential tools for monitoring sewage contamination in subtropical estuaries.

PubMed

Cabral, Ana Caroline; Stark, Jonathan S; Kolm, Hedda E; Martins, César C

2018-04-01

Sewage input and the relationship between chemical markers (linear alkylbenzenes and coprostanol) and fecal indicator bacteria (FIB, Escherichia coli and enterococci), were evaluated in order to establish thresholds values for chemical markers in suspended particulate matter (SPM) as indicators of sewage contamination in two subtropical estuaries in South Atlantic Brazil. Both chemical markers presented no linear relationship with FIB due to high spatial microbiological variability, however, microbiological water quality was related to coprostanol values when analyzed by logistic regression, indicating that linear models may not be the best representation of the relationship between both classes of indicators. Logistic regression was performed with all data and separately for two sampling seasons, using 800 and 100 MPN 100 mL -1 of E. coli and enterococci, respectively, as the microbiological limits of sewage contamination. Threshold values of coprostanol varied depending on the FIB and season, ranging between 1.00 and 2.23 μg g -1 SPM. The range of threshold values of coprostanol for SPM are relatively higher and more variable than those suggested in literature for sediments (0.10-0.50 μg g -1 ), probably due to higher concentration of coprostanol in SPM than in sediment. Temperature may affect the relationship between microbiological indicators and coprostanol, since the threshold value of coprostanol found here was similar to tropical areas, but lower than those found during winter in temperate areas, reinforcing the idea that threshold values should be calibrated for different climatic conditions. Copyright © 2018 Elsevier Ltd. All rights reserved.

High temperature spin-glass-like transition in La0.67Sr0.33MnO3 nanofibers near the Curie point.

PubMed

Lu, Ruie; Yang, Sen; Li, Yitong; Chen, Kaiyun; Jiang, Yun; Fu, Bi; Zhang, Yin; Zhou, Chao; Xu, Minwei; Zhou, Xuan

2017-06-28

The glassy transition of superparamagnetic (SPM) (r < r 0 ) nanoparticle systems usually occurs at a very low temperature that greatly limits its application to high temperatures. In this work, we report a spin-glass-like (SGL) behavior near the Curie point (T C ), i.e., T 0 = 330 K, in La 0.67 Sr 0.33 MnO 3 (LSMO) nanofibers (NFs) composed of nanoparticles beyond the SPM size (r ≫ r 0 ), resulting in a significant increase of the glass transition temperature. This SGL transition near the T C of bulk LSMO can be explained to be the scenario of locally ordered clusters embedded in a disordered host, in which the assembly of nanoparticles has a magnetic core-shell model driven by surface spin glass. The presence of a surface spin glass of nanoparticles was proved by the Almeida-Thouless line δT f ∝ H 2/3 , exchange bias, and reduced saturation magnetization of the NF system. Composite dynamics were found - that is, both the SPM and the super-spin-glass (SSG) behavior are found in such an NF system. The bifurcation of the zero-field-cooled (ZFC) and field-cooled (FC) magnetization vs. temperature curves at the ZFC peak, and the flatness of FC magnetization involve SSG, while the frequency-dependent ac susceptibility anomaly follows the Vogel-Fulcher law that implies weak dipole interactions of the SPM model. This finding can help us to find a way to search for high temperature spin glass materials.

Heavy metal contamination of a Greenland Fjord system by mine wastes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Loring, D.H.; Asmund, G.

Since 1973, about 500,000 tons/yr of metal-rich particulate tailings from a lead/zinc flotation mill have been discharged through a submarine outfall into a two-fjord system on the west coast of Greenland. Differential solubilization of particulate metals by seawater, seasonal water mixing, and sill exchange tailings dispersal processes have resulted in high, but seasonally variable, Zn, Cd, and Pb contamination of the water and suspended particulate matter (SPM). Chemical partition of the SPM shows that most of the Pb, but relatively low proportions of Zn and Cd are weakly bound to the SPM. Such particulate metal characteristics allow the real timemore » effects of tailings discharges and dispersal on the system to be traced even in the sediments where tailings accumulation is very slow. Fjord seaweeds and blue mussels also contain varying amounts of Zn, Pb, and Cd, depending on the metal and their location relative to the tailings outfall. They apparently responded almost instantly to the metal contamination as did the water and SPM. High Pb concentrations in the fjord mussels most likely derive from the preferential uptake of available particulate Pb, whereas the seaweeds appear to derive most of their heavy metal concentrations from the dissolved phase. The evidence from this and other sites, and from experimental work, indicates that any discharge of Pb-particles into the marine environment, either directly as mine wastes or indirectly from natural runoff from current and former lead mining sites, results in immediate lead contamination of the in situ mussel population. 20 refs., 4 figs., 5 tab.« less

The effect of substrate on electric field enhancement of Tip-enhanced Raman spectroscopy (TERS)

NASA Astrophysics Data System (ADS)

Bahreini, Maryam

2018-01-01

The characterization of materials down to a few-molecule level is a key challenge in nanotechnology. Raman spectroscopy is a powerful method that provides chemical information via nondestructive vibrational fingerprinting. Unfortunately, this method suffers from signal weakness which prevents the study of small quantities. Tip-enhanced Raman spectroscopy (TERS) which combines the chemical sensitivity of Raman spectroscopy (RS) with high spatial resolution of scanning probe microscopy (SPM), provides chemical images of surfaces at the nanometer scale. In this method, irradiation of an SPM tip by a focused laser beam results in enhancement of local electric field via two reasons of localized surface plasmon resonance and lightning rod effect. This enhancement leads to the enhancement in Raman intensity from the sample surface in the vicinity of tip. In all TERS measurements, samples should be located on a substrate. In this paper, the dependence of the electric field enhancement to the substrate has been investigated. In simulations, three-dimensional finite-difference time-domain (3D-FDTD) method is used for numerical solution of Maxwell's equations. Our results show that the electric field enhancement is weak for the tip alone case. Introducing a substrate provides further electric field enhancement via near field electromagnetic dipole-dipole coupling between the tip and substrate. Since the side-illumination geometry is used for laser irradiation, the vertical component of the incident field plays a dominant role in the electric field enhancement. Therefore, the coupling effect between the tip and the substrate is the key contribution to the enhancement. For the case of silicon tip and the gold substrate, the electric field enhancement is improved considerably. There is an optimal tip size for TERS because of the competing effects of the radiation damping and the surface scattering of the tip. The results show the substrate as an effective tool for the improvement of the TERS detection sensitivity.

New positive feedback mechanism between boundary layer meteorology and secondary aerosol formation during severe haze events

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Quan; Jia, Xingcan; Quan, Jiannong

Severe haze events during which particulate matter (PM) increases quickly from tens to hundreds of microgram per cubic meter in 1-2 days frequently occur in China. Although it has been known that PM is influenced by complex interplays among emissions, meteorology, and physical and chemical processes, specific mechanisms remain elusive. In this paper, a new positive feedback mechanism between planetary boundary layer (PBL), relative humidity (RH), and secondary PM (SPM) formation is proposed based on a comprehensive field experiment and model simulation. The decreased PBL associated with increased PM increases RH by weakening the vertical transport of water vapor; themore » increased RH in turn enhances the SPM formation through heterogeneous aqueous reactions, which further enhances PM, weakens solar radiation, and decreases PBL height. This positive feedback, together with the PM-Radiation-PBL feedback, constitutes a key mechanism that links PM, radiation, PBL properties (e.g. PBL height and RH), and SPM formation, This mechanism is self-amplifying, leading to faster PM production, accumulation, and more severe haze pollution.« less

Risk of second primary malignancies and survival of adult patients with polycythemia vera: A United States population-based retrospective study.

PubMed

Khanal, Nabin; Giri, Smith; Upadhyay, Smrity; Shostrom, Valerie K; Pathak, Ranjan; Bhatt, Vijaya Raj

2016-01-01

Although the median survival in polycythemia vera (PV) is 14 years, mortality is higher than in an age- and sex-matched population. This study included 3941 PV patients diagnosed between 2000-2012 from Surveillance, Epidemiology and End Results (SEER) 13 registry to determine 5-year survival and the incidence of second primary malignancies (SPM). The actuarial 5 year survival in the overall cohort was 79.5%. The cumulative incidence of SPM was 13.1% at 10 years. SPMs occurred at a standardized incidence ratio (SIR) of 1.29 (95% CI = 1.16-1.43; p < 0.001) with an absolute excess risk (AER) of 42.49 per 10 000 population. A significantly higher risk was noted for acute myeloid leukemia (SIR = 12.24; 95% CI = 8.17-17.8; p-value < 0.001) and chronic myeloid leukemia (SIR = 10.66; 95% CI = 3.75-19.6; p-value < 0.001). Patients with PV are at a high risk of SPM and leukemic transformation, which may compromise long-term survival.

Support of surgical process modeling by using adaptable software user interfaces

NASA Astrophysics Data System (ADS)

Neumuth, T.; Kaschek, B.; Czygan, M.; Goldstein, D.; Strauß, G.; Meixensberger, J.; Burgert, O.

2010-03-01

Surgical Process Modeling (SPM) is a powerful method for acquiring data about the evolution of surgical procedures. Surgical Process Models are used in a variety of use cases including evaluation studies, requirements analysis and procedure optimization, surgical education, and workflow management scheme design. This work proposes the use of adaptive, situation-aware user interfaces for observation support software for SPM. We developed a method to support the modeling of the observer by using an ontological knowledge base. This is used to drive the graphical user interface for the observer to restrict the search space of terminology depending on the current situation. In the evaluation study it is shown, that the workload of the observer was decreased significantly by using adaptive user interfaces. 54 SPM observation protocols were analyzed by using the NASA Task Load Index and it was shown that the use of the adaptive user interface disburdens the observer significantly in workload criteria effort, mental demand and temporal demand, helping him to concentrate on his essential task of modeling the Surgical Process.

Airborne particulate matter and spacecraft internal environments

NASA Technical Reports Server (NTRS)

Liu, Benjamin Y. H.; Rubow, Kenneth L.; Mcmurry, Peter H.; Kotz, Thomas J.; Russo, Dane

1991-01-01

Instrumentation, consisting of a Shuttle Particle Sampler (SPS) and a Shuttle Particle Monitor (SPM), has been developed to characterize the airborne particulate matter in the Space Shuttle cabin during orbital flight. The SPS size selectively collects particles in four size fractions (0-2.5, 2.5-10, 10-100, and greater than 100 microns) which are analyzed postflight for mass concentration and size distribution, elemental composition, and morphology. The SPM provides a continuous record of particle concentration through photometric light scattering. Measurements were performed onboard Columbia, OV-102, during the flight of STS-32 in January 1990. No significant changes were observed in the particle mass concentration, size distribution, or chemical composition in samples collected during flight-day 2 and flight-day 7. The total mass concentration was 56 microg/cu cm with approximately half of the particles larger than 100 microns. Elemental analysis showed that roughly 70 percent of the particles larger than 2.5 microns were carbonaceous with small amounts of other elements present. The SPM showed no temporal or spatial variation in particle mass concentration during the mission.

The effects of plant growth regulators and L-phenylalanine on phenolic compounds of sweet basil.

PubMed

Koca, Nülüfer; Karaman, Şengül

2015-01-01

The effects of methyl jasmonate (MeJA), spermine (Spm), epibrassinolide (EBL) and l-phenylalanine on sweet basil (Ocimum basilicum L.) were studied to determine the amount of phenolic compounds and enzymatic activity of phenylalanine ammonia-lyase (PAL). Total phenolic and total flavonoid contents of sweet basils were determined by a spectrophotometer, and individual phenolic compounds and activity of PAL were analysed by HPLC/UV. The highest total phenolic (6.72 mg GAE/g) and total flavonoid contents (0.92 mg QE/g) obtained from 1.0 mM Spm+MeJA application. Rosmarinic acid (RA) and caffeic acid contents significantly enhanced after the applications but no such differences observed in chicoric acid content or PAL activity. RA was the main phenolic acid in all samples and its concentration varied from 1.04 to 2.70 mg/gFW. As a result the combinations of Spm+MeJA and EBL+MeJA can induce secondary metabolites effectively and those interactions play important role in the production of phytochemicals in plants. Copyright © 2014 Elsevier Ltd. All rights reserved.

Occurrence, distribution, and risk assessment of alkylphenols, bisphenol A, and tetrabromobisphenol A in surface water, suspended particulate matter, and sediment in Taihu Lake and its tributaries.

PubMed

Liu, Dan; Liu, Jining; Guo, Min; Xu, Huaizhou; Zhang, Shenghu; Shi, Lili; Yao, Cheng

2016-11-15

The occurrence and distribution of nine selected compounds were investigated in surface water, suspended particulate matter (SPM), and sediment in Taihu Lake and its tributaries. With the exception of 4-Butylphenol, all compounds were detected in at least two phases, and nonylphenol (NP) and 4-tert-Octylphenol (4-OP) were the predominant alkylphenols (APs) in the lake. A significant correlation was observed between NP and 4-OP, indicating that they may share the same source. Moreover, surface water phase was the dominant sink of Bisphenol A (BPA) in the aquatic environment. The concentrations of BPA between the surface water and SPM phases were closely related to each other. In addition, Tetrabromobisphenol A (TBBPA) exhibited relatively higher concentrations and detection frequencies in the SPM. Risk assessment revealed greater risk associated with the surface water than the sediment, indicating that the discharge of industrial wastewater and domestic sewage poses a serious threat to aquatic ecosystems. Copyright © 2016 Elsevier Ltd. All rights reserved.

New positive feedback mechanism between boundary layer meteorology and secondary aerosol formation during severe haze events

DOE PAGES

Liu, Quan; Jia, Xingcan; Quan, Jiannong; ...

2018-04-17

Severe haze events during which particulate matter (PM) increases quickly from tens to hundreds of microgram per cubic meter in 1-2 days frequently occur in China. Although it has been known that PM is influenced by complex interplays among emissions, meteorology, and physical and chemical processes, specific mechanisms remain elusive. In this paper, a new positive feedback mechanism between planetary boundary layer (PBL), relative humidity (RH), and secondary PM (SPM) formation is proposed based on a comprehensive field experiment and model simulation. The decreased PBL associated with increased PM increases RH by weakening the vertical transport of water vapor; themore » increased RH in turn enhances the SPM formation through heterogeneous aqueous reactions, which further enhances PM, weakens solar radiation, and decreases PBL height. This positive feedback, together with the PM-Radiation-PBL feedback, constitutes a key mechanism that links PM, radiation, PBL properties (e.g. PBL height and RH), and SPM formation, This mechanism is self-amplifying, leading to faster PM production, accumulation, and more severe haze pollution.« less

Effect of SPM-based cleaning POR on EUV mask performance

NASA Astrophysics Data System (ADS)

Choi, Jaehyuck; Lee, Han-shin; Yoon, Jinsang; Shimomura, Takeya; Friz, Alex; Montgomery, Cecilia; Ma, Andy; Goodwin, Frank; Kang, Daehyuk; Chung, Paul; Shin, Inkyun; Cho, H.

2011-11-01

EUV masks include many different layers of various materials rarely used in optical masks, and each layer of material has a particular role in enhancing the performance of EUV lithography. Therefore, it is crucial to understand how the mask quality and patterning performance can change during mask fabrication, EUV exposure, maintenance cleaning, shipping, or storage. The fact that a pellicle is not used to protect the mask surface in EUV lithography suggests that EUV masks may have to undergo more cleaning cycles during their lifetime. More frequent cleaning, combined with the adoption of new materials for EUV masks, necessitates that mask manufacturers closely examine the performance change of EUV masks during cleaning process. We have investigated EUV mask quality and patterning performance during 30 cycles of Samsung's EUV mask SPM-based cleaning and 20 cycles of SEMATECH ADT exposure. We have observed that the quality and patterning performance of EUV masks does not significantly change during these processes except mask pattern CD change. To resolve this issue, we have developed an acid-free cleaning POR and substantially improved EUV mask film loss compared to the SPM-based cleaning POR.

An Improved Fungal Mounting Technique for Nomarski Microscopy.

ERIC Educational Resources Information Center

Fairclough, Andrew; And Others

1985-01-01

Conventional sellotape techniques for fungal mounting produce interference patterns when using Normarsky microscopy. A technique is described which overcomes this problem and produces a permanent mount with a completely clear background. (Author/JN)

Magneto-optical properties of α-Fe2O3@ZnO nanocomposites prepared by the high energy ball-milling technique

NASA Astrophysics Data System (ADS)

Chaudhury, Chandana Roy; Roychowdhury, Anirban; Das, Anusree; Das, Dipankar

2016-05-01

Magnetic-fluorescent nanocomposites (NCs) with 10 wt% of α-Fe2O3 in ZnO have been prepared by the high energy ball-milling. The crystallite sizes of α-Fe2O3 and ZnO in the NCs are found to vary from 65 nm to 20 nm and 47 nm to 15 nm respectively as milling time is increased from 2 to 30 h. XRD analysis confirms presence of α-Fe2O3 and ZnO in pure form in all the NCs. UV-vis study of the NCs shows a continuous blue-shift of the absorption peak and a steady increase of band gap of ZnO with increasing milling duration that are assigned to decreasing particle size of ZnO in the NCs. Photoluminescence (PL) spectra of the NCs reveal three weak emission bands in the visible region at 421, 445 and 485 nm along with the strong near band edge emission at 391 nm. These weak emission bands are attributed to different defect - related energy levels e.g. Zn-vacancy, Zn interstitial and oxygen vacancy. Dc and ac magnetization measurements show presence of weakly interacting superparamagnetic (SPM) α-Fe2O3 particles in the NCs. 57Fe-Mössbauer study confirms presence of SPM hematite in the sample milled for 30 h. Positron annihilation lifetime measurements indicate presence of cation vacancies in ZnO nanostructures confirming results of PL studies.

Detection of Metallo-β-Lactamase Producing Pseudomonas aeruginosa Isolated from Public and Private Hospitals in Baghdad, Iraq.

PubMed

Al-Charrakh, Alaa H; Al-Awadi, Salwa J; Mohammed, Ahmed S

2016-02-01

Metallo-β-lactamase (MBL) producing Pseudomonas aeruginosa has been reported to be an important nosocomial infection. Its intrinsic and acquired resistance to various antimicrobial agents and its ability to develop multidrug resistance imposes a serious therapeutic problem. Different clinical samples were collected from public and private hospitals in Baghdad city, Iraq. Bacterial identification was done using conventional cultural, biochemical tests, and VITEk 2 system. Minimum inhibitory concentration (MIC) testing was performed using VITEK 2 automated system. Each P. aeruginosa isolates showed resistance to Carbapenems (Imipenem and Meropenem) were subjected to Imipenem-EDTA combined disc synergy test (CDST) to investigate the production of MBL (confirmative test). The presence of bla-genes encoded IMP, VIM, and SPM-1 was detected by conventional PCR technique. A total of 75 P. aeruginosa isolates were isolated, 16 (21.3%) were able to grow on MacConkey agar supplemented with Meropenem 4mg/L (MMAC). The MIC of different antibiotics showed that 6 (37.5 %) isolates were Carbapenem resistant, MIC ≥16 µg/ml while 4 (25%) isolates appear to be MBL producer using CDST test. PCR assay revealed that 3 (50%), 1 (16.6%) of the carbapenem resistant isolates harbored blaIMP, blaSPM-1 genes, respectively. blaVIM gene was not detected in this study. The prevalence of multi-drug resistant P. aeruginosa isolates especially Carbapenem resistant bacteria was increased in Baghdad province. The blaIMP was the predominant among the MBLs genes in P. aeruginosa in this study.

STAPP: Spatiotemporal analysis of plantar pressure measurements using statistical parametric mapping.

PubMed

Booth, Brian G; Keijsers, Noël L W; Sijbers, Jan; Huysmans, Toon

2018-05-03

Pedobarography produces large sets of plantar pressure samples that are routinely subsampled (e.g. using regions of interest) or aggregated (e.g. center of pressure trajectories, peak pressure images) in order to simplify statistical analysis and provide intuitive clinical measures. We hypothesize that these data reductions discard gait information that can be used to differentiate between groups or conditions. To test the hypothesis of null information loss, we created an implementation of statistical parametric mapping (SPM) for dynamic plantar pressure datasets (i.e. plantar pressure videos). Our SPM software framework brings all plantar pressure videos into anatomical and temporal correspondence, then performs statistical tests at each sampling location in space and time. Novelly, we introduce non-linear temporal registration into the framework in order to normalize for timing differences within the stance phase. We refer to our software framework as STAPP: spatiotemporal analysis of plantar pressure measurements. Using STAPP, we tested our hypothesis on plantar pressure videos from 33 healthy subjects walking at different speeds. As walking speed increased, STAPP was able to identify significant decreases in plantar pressure at mid-stance from the heel through the lateral forefoot. The extent of these plantar pressure decreases has not previously been observed using existing plantar pressure analysis techniques. We therefore conclude that the subsampling of plantar pressure videos - a task which led to the discarding of gait information in our study - can be avoided using STAPP. Copyright © 2018 Elsevier B.V. All rights reserved.

In vivo microscopy of the mouse brain using multiphoton laser scanning techniques

NASA Astrophysics Data System (ADS)

Yoder, Elizabeth J.

2002-06-01

The use of multiphoton microscopy for imaging mouse brain in vivo offers several advantages and poses several challenges. This tutorial begins by briefly comparing multiphoton microscopy with other imaging modalities used to visualize the brain and its activity. Next, an overview of the techniques for introducing fluorescence into whole animals to generate contrast for in vivo microscopy using two-photon excitation is presented. Two different schemes of surgically preparing mice for brain imaging with multiphoton microscopy are reviewed. Then, several issues and problems with in vivo microscopy - including motion artifact, respiratory and cardiac rhythms, maintenance of animal health, anesthesia, and the use of fiducial markers - are discussed. Finally, examples of how these techniques have been applied to visualize the cerebral vasculature and its response to hypercapnic stimulation are provided.

Dictionary of Microscopy

NASA Astrophysics Data System (ADS)

Heath, Julian

2005-10-01

The past decade has seen huge advances in the application of microscopy in all areas of science. This welcome development in microscopy has been paralleled by an expansion of the vocabulary of technical terms used in microscopy: terms have been coined for new instruments and techniques and, as microscopes reach even higher resolution, the use of terms that relate to the optical and physical principles underpinning microscopy is now commonplace. The Dictionary of Microscopy was compiled to meet this challenge and provides concise definitions of over 2,500 terms used in the fields of light microscopy, electron microscopy, scanning probe microscopy, x-ray microscopy and related techniques. Written by Dr Julian P. Heath, Editor of Microscopy and Analysis, the dictionary is intended to provide easy navigation through the microscopy terminology and to be a first point of reference for definitions of new and established terms. The Dictionary of Microscopy is an essential, accessible resource for: students who are new to the field and are learning about microscopes equipment purchasers who want an explanation of the terms used in manufacturers' literature scientists who are considering using a new microscopical technique experienced microscopists as an aide mémoire or quick source of reference librarians, the press and marketing personnel who require definitions for technical reports.

Protein classification using sequential pattern mining.

PubMed

Exarchos, Themis P; Papaloukas, Costas; Lampros, Christos; Fotiadis, Dimitrios I

2006-01-01

Protein classification in terms of fold recognition can be employed to determine the structural and functional properties of a newly discovered protein. In this work sequential pattern mining (SPM) is utilized for sequence-based fold recognition. One of the most efficient SPM algorithms, cSPADE, is employed for protein primary structure analysis. Then a classifier uses the extracted sequential patterns for classifying proteins of unknown structure in the appropriate fold category. The proposed methodology exhibited an overall accuracy of 36% in a multi-class problem of 17 candidate categories. The classification performance reaches up to 65% when the three most probable protein folds are considered.

Multi data mode method as an alternative way for SPM studies of high relief surfaces

NASA Astrophysics Data System (ADS)

Abdullayeva, S. H.; Molchanov, S. P.; Mamedov, N. T.; Alekperov, S. D.

2006-09-01

In this paper we report the results of our studies of the high relief surfaces of Al oxide-based ceramic catalyst by SPM contact mode, and by so-called Multi Data Mode (MDM) method for comparison. We failed to obtain any reasonable image of the highly-developed surfaces of above material by the first method but were successful in doing so when applied the second one. The topographic and complimentary images obtained by MDM probing with high resolution are discussed to show a full range of the applications possible using MDM.

Mix & match electron beam & scanning probe lithography for high throughput sub-10 nm lithography

NASA Astrophysics Data System (ADS)

Kaestner, Marcus; Hofer, Manuel; Rangelow, Ivo W.

2013-03-01

The prosperous demonstration of a technique able to produce features with single nanometer (SN) resolution could guide the semiconductor industry into the desired beyond CMOS era. In the lithographic community immense efforts are being made to develop extreme ultra-violet lithography (EUVL) and multiple-e-beam direct-write systems as possible successor for next generation lithography (NGL). However, patterning below 20 nm resolution and sub-10 nm overlay alignment accuracy becomes an extremely challenging quest. Herein, the combination of electron beam lithography (EBL) or EUVL with the outstanding capabilities of closed-loop scanning proximal probe nanolithography (SPL) reveals a promising way to improve both patterning resolution and reproducibility in combination with excellent overlay and placement accuracy. In particular, the imaging and lithographic resolution capabilities provided by scanning probe microscopy (SPM) methods touches the atomic level, which expresses the theoretical limit of constructing nanoelectronic devices. Furthermore, the symbiosis between EBL (EUVL) and SPL expands the process window of EBL (EUVL) far beyond state-of-the-art allowing SPL-based pre- and post-patterning of EBL (EUVL) written features at critical dimension level with theoretically nanometer precise pattern overlay alignment. Moreover, we can modify the EBL (EUVL) pattern before as well as after the development step. In this paper we demonstrate proof of concept using the ultra-high resolution molecular glass resist calixarene. Therefor we applied Gaussian E-beam lithography system operating at 10 keV and a home-developed SPL set-up. The introduced Mix and Match lithography strategy enables a powerful use of our SPL set-up especially as post-patterning tool for inspection and repair functions below the sub-10 nm critical dimension level.

Techniques for 3D tracking of single molecules with nanometer accuracy in living cells

NASA Astrophysics Data System (ADS)

Gardini, Lucia; Capitanio, Marco; Pavone, Francesco S.

2013-06-01

We describe a microscopy technique that, combining wide-field single molecule microscopy, bifocal imaging and Highly Inclined and Laminated Optical sheet (HILO) microscopy, allows a 3D tracking with nanometer accuracy of single fluorescent molecules in vitro and in living cells.

Surface Characterization.

ERIC Educational Resources Information Center

Fulghum, J. E.; And Others

1989-01-01

This review is divided into the following analytical methods: ion spectroscopy, electron spectroscopy, scanning tunneling microscopy, atomic force microscopy, optical spectroscopy, desorption techniques, and X-ray techniques. (MVL)

Reactive oxygen species and nitric oxide are involved in polyamine-induced growth inhibition in wheat plants.

PubMed

Recalde, Laura; Vázquez, Analía; Groppa, María D; Benavides, María Patricia

2018-03-06

Polyamines (PAs) produce H 2 O 2 and nitric oxide (NO) during their normal catabolism and modulate plant growth and development. To explore the biochemical basis of PAs-induced growth inhibition in Triticum aestivum L seedlings, we examined the role of O 2 ·- , H 2 O 2 or NO in shoot and root development. Although all PA treatments resulted in a variable reduction of root and shoot elongation, spermine (Spm) caused the greater inhibition in a similar way to that observed with the NO donor, sodium nitroprusside (SNP). In both cases, O 2 ·- production was completely blocked whereas H 2 O 2 formation was high in the root apex under SNP or Spm treatments. Catalase recovered root and shoot growth in SNP but not in Spm-treated plants, revealing the involvement of H 2 O 2 in SNP-root length reduction. The addition of the NO scavenger, cPTIO, restored root length in SNP- or Spm-treated plants, respectively, and partially recovered O 2 ·- levels, compared to the plants exposed to PAs or SNP without cPTIO. A strong correlation was observed between root growth restoration and O 2 ·- accumulation after treating roots with SNP + aminoguanidine, a diamine oxidase inhibitor, and with SNP + 1,8-diaminoctane, a polyamine oxidase inhibitor, confirming the essential role of O 2 ·- formation for root growth and the importance of the origin and level of H 2 O 2 . The differential modulation of wheat growth by PAs through reactive oxygen species or NO is discussed. Graphical abstract Polyamines, nitric oxide and ROS interaction in plants during plant growth.

Inhibition of ATPase activity in rat synaptic plasma membranes by simultaneous exposure to metals.

PubMed

Carfagna, M A; Ponsler, G D; Muhoberac, B B

1996-03-08

Inhibition of Na+/K+-ATPase and Mg2+-ATPase activities by in vitro exposure to Cd2+, Pb2+ and Mn2+ was investigated in rat brain synaptic plasma membranes (SPMs). Cd2+ and Pb2+ produced a larger maximal inhibition of Na+/K+-ATPase than of Mg2+-ATPase activity. Metal concentrations causing 50% inhibition of Na+/K+-ATPase activity (IC50 values) were Cd2+ (0.6 microM) < Pb2+ (2.1 microM) < Mn2+ (approximately 3 mM), and the former two metals were substantially more potent in inhibiting SPM versus synaptosomal Na+/K+-ATPase. Dixon plots of SPM data indicated that equilibrium binding of metals occurs at sites causing enzyme inhibition. In addition, IC50 values for SPM K+-dependent p-nitrophenylphosphatase inhibition followed the same order and were Cd2+ (0.4 microM) < Pb2+ (1.2 microM) < Mn2+ (300 microM). Simultaneous exposure to the combinations Cd2+/Mn2+ or Pb2+/Mn2+ inhibited SPM Na+/K+-ATPase activity synergistically (i.e., greater than the sum of the metal-induced inhibitions assayed separately), while Cd2+/Pb2+ caused additive inhibition. Simultaneous exposure to Cd2+/Pb2+ antagonistically inhibited Mg2+-ATPase activity while Cd2+/Mn2+ or Pb2+/Mn2+ additively inhibited Mg2+-ATPase activity at low Mn2+ concentrations, but inhibited antagonistically at higher concentrations. The similar IC50 values for Cd2+ and Pb2+ versus Mn2+ inhibition of Na+/K+-ATPase and the pattern of inhibition/activation upon exposure to two metals simultaneously support similar modes of interaction of Cd2+ and Pb2+ with this enzyme, in agreement with their chemical reactivities.

Automated determination of polyamines by high-performance liquid chromatography with simple sample preparation.

PubMed

van Eijk, H M; Rooyakkers, D R; Deutz, N E

1996-04-12

Recently, a new fully endcapped reversed-phase packing material, Inertsil, was introduced, especially suitable for the determination of basic compounds. We used this packing material to separate ophthaldialdehyde (OPA) derivatives of amino acid derivatives completely from the OPA derivatives of spermine (SPM), spermidine (SPD), putrescine (PUT) and cadaverine (CAD). The obtained separation made the commonly used off-line extraction procedure redundant and thus an on-line sample clean-up was introduced. This enabled automation of the procedure resulting in a better reproducibility and a more efficient use of equipment. Furthermore, no studies are required to determine the extraction recovery. The present method has a cycle time of 30 min. A linear response for each polyamine was found up to 250 pmol, with an R2 ranging from 0.9981 (SPM) to 0.9998 (CAD). The limit of detection, calculated at a signal-to-noise ratio of 3, was 0.1 pmol, corresponding to a plasma concentration of 0.1 mumol/l. The coefficient of variation (C.V.) for the peak area was below 3% and for retention times below 0.5% (n = 15). In order to evaluate the applicability of the method, three different types of sample were chromatographed, e.g. urine (obtained from healthy human volunteers), pig plasma and sulfosalicylic acid homogenates of pig intestine biopsies. Tissue homogenates and urine-specimen could easily be quantitated, while plasma concentrations were just above the limit of detection, resulting in a plasma C.V. ranging from 4.8% (SPM) to 13.6% (SPD) and a tissue C.V. ranging from 2.1% (SPM) to 8.5% (CAD), The urinary C.V.s were not determined. In conclusion, the present method provides an easy way to measure polyamine concentrations for most applications.

Bloodstream infections caused by multi-drug resistant Proteus mirabilis: Epidemiology, risk factors and impact of multi-drug resistance.

PubMed

Korytny, Alexander; Riesenberg, Klaris; Saidel-Odes, Lisa; Schlaeffer, Fransisc; Borer, Abraham

2016-01-01

The prevalence of antimicrobial co-resistance among ESBL-producing Enterobactereaceae is extremely high in Israel. Multidrug-resistant Proteus mirabilis strains (MDR-PM), resistant to almost all antibiotic classes have been described. The aim was to determine the risk factors for bloodstream infections caused by MDR-PM and clinical outcomes. A retrospective case-control study. Adult patients with PM bacteremia during 7 years were identified retrospectively and their files reviewed for demographics, underlying diseases, Charlson Comorbidity Index, treatment and outcome. One hundred and eighty patients with PM-bloodstream infection (BSI) were included; 90 cases with MDR-PM and 90 controls with sensitive PM (S-PM). Compared to controls, cases more frequently were from nursing homes, had recurrent hospital admissions in the past year and received antibiotic therapy in the previous 3 months, were bedridden and suffered from peripheral vascular disease and peptic ulcer disease (p < 0.001). Two-thirds of the MDR-PM isolates were ESBL-producers vs 4.4% of S-PM isolates (p < 0.001, OR = 47.6, 95% CI = 15.9-142.6). In-hospital crude mortality rate of patients with MDR-PM BSI was 37.7% vs 23.3% in those with S-PM BSI (p = 0.0359, OR = 2, 95% CI = 1.4-3.81). PM bacteremia in elderly and functionally-dependent patients is likely to be caused by nearly pan-resistant PM strains in the institution; 51.8% of the patients received inappropriate empiric antibiotic treatment. The crude mortality rate of patients with MDR-PM BSI was significantly higher than that of patients with S-PM BSI.

Prescribing joint co-ordinates during model preparation to improve inverse kinematic estimates of elbow joint angles.

PubMed

Wells, D J M; Alderson, J A; Dunne, J; Elliott, B C; Donnelly, C J

2017-01-25

To appropriately use inverse kinematic (IK) modelling for the assessment of human motion, a musculoskeletal model must be prepared 1) to match participant segment lengths (scaling) and 2) to align the model׳s virtual markers positions with known, experimentally derived kinematic marker positions (marker registration). The purpose of this study was to investigate whether prescribing joint co-ordinates during the marker registration process (within the modelling framework OpenSim) will improve IK derived elbow kinematics during an overhead sporting task. To test this, the upper limb kinematics of eight cricket bowlers were recorded during two testing sessions, with a different tester each session. The bowling trials were IK modelled twice: once with an upper limb musculoskeletal model prepared with prescribed participant specific co-ordinates during marker registration - MR PC - and once with the same model prepared without prescribed co-ordinates - MR; and by an established direct kinematic (DK) upper limb model. Whilst both skeletal model preparations had strong inter-tester repeatability (MR: Statistical Parametric Mapping (SPM1D)=0% different; MR PC : SPM1D=0% different), when compared with DK model elbow FE waveform estimates, IK estimates using the MR PC model (RMSD=5.2±2.0°, SPM1D=68% different) were in closer agreement than the estimates from the MR model (RMSD=44.5±18.5°, SPM1D=100% different). Results show that prescribing participant specific joint co-ordinates during the marker registration phase of model preparation increases the accuracy and repeatability of IK solutions when modelling overhead sporting tasks in OpenSim. Copyright © 2016 Elsevier Ltd. All rights reserved.

Distributed Source Modeling of Language with Magnetoencephalography: Application to Patients with Intractable Epilepsy

PubMed Central

McDonald, Carrie R.; Thesen, Thomas; Hagler, Donald J.; Carlson, Chad; Devinksy, Orrin; Kuzniecky, Rubin; Barr, William; Gharapetian, Lusineh; Trongnetrpunya, Amy; Dale, Anders M.; Halgren, Eric

2009-01-01

Purpose To examine distributed patterns of language processing in healthy controls and patients with epilepsy using magnetoencephalography (MEG), and to evaluate the concordance between laterality of distributed MEG sources and language laterality as determined by the intracarotid amobarbitol procedure (IAP). Methods MEG was performed in ten healthy controls using an anatomically-constrained, noise-normalized distributed source solution (dSPM). Distributed source modeling of language was then applied to eight patients with intractable epilepsy. Average source strengths within temporoparietal and frontal lobe regions of interest (ROIs) were calculated and the laterality of activity within ROIs during discrete time windows was compared to results from the IAP. Results In healthy controls, dSPM revealed activity in visual cortex bilaterally from ~80-120ms in response to novel words and sensory control stimuli (i.e., false fonts). Activity then spread to fusiform cortex ~160-200ms, and was dominated by left hemisphere activity in response to novel words. From ~240-450ms, novel words produced activity that was left-lateralized in frontal and temporal lobe regions, including anterior and inferior temporal, temporal pole, and pars opercularis, as well as bilaterally in posterior superior temporal cortex. Analysis of patient data with dSPM demonstrated that from 350-450ms, laterality of temporoparietal sources agreed with the IAP 75% of the time, whereas laterality of frontal MEG sources agreed with the IAP in all eight patients. Discussion Our results reveal that dSPM can unveil the timing and spatial extent of language processes in patients with epilepsy and may enhance knowledge of language lateralization and localization for use in preoperative planning. PMID:19552656

Geochemistry of the suspended sediment in the estuaries of the Mandovi and Zuari rivers, central west coast of India.

PubMed

Kessarkar, Pratima M; Shynu, R; Rao, V Purnachandra; Chong, Feng; Narvekar, Tanuja; Zhang, Jing

2013-05-01

The geochemistry of the suspended particulate matter (SPM) collected during the monsoon was determined to identify the sources of SPM and to understand the physicochemical processes in the Mandovi and Zuari river estuaries. The concentrations of SPM decrease seaward in both estuaries, but are relatively high at bay stations. Kaolinite is the most dominant clay mineral in the upstream of both rivers. Smectite increases seaward in both estuaries and is abundant in the bay. Upstream stations of Mandovi, where ore deposits are stored on the shore, exhibit high Fe, Mn, total rare earth elements (∑REE), and middle REE- and heavy REE-enriched patterns. Channel stations of both estuaries exhibit middle REE- and light REE-enriched patterns, which gradually changed seaward to middle REE- and heavy REE-enriched patterns. Canal stations exhibit the highest concentrations of major and trace metals. High metal/Al ratios occur at stations in the upstream of Zuari and at the confluence of canals in the Mandovi estuary. Enrichment factors of metals indicate that Mn is significantly polluted while other metals are moderately polluted. The δ(13)C and δ(15)N of organic matter indicate that the terrigenous organic matter at the upstream is diluted seaward by marine organic matter. Organic matter at bay stations is largely marine and altered-type. The compositions of SPM are controlled by the particulates from ore dust, the geology of the drainage basins, and the physicochemical processes in the estuaries. Particulates resuspended from the bay are dominated by ore dust, which are advected into the channels of both estuaries during the lull periods of the monsoon.

Comparison and validation of the aerosol optical depth obtained with the Langley plot method in the UV-B from Brewer Ozone Spectrophotometer measurements

NASA Astrophysics Data System (ADS)

Cheymol, Anne; de Backer, Hugo; Josefsson, Weine; Stübi, René

2006-08-01

The Aerosol Optical Depths (AODs) retrieved from Brewer Ozone Spectrophotometer measurements with a method previously developed (Cheymol and De Backer, 2003) are now validated by comparisons between AODs from six Brewer spectrophotometers and two CSEM SPM2000 sunphotometers: two Brewer spectrophotometers 016 and 178 at Uccle in Belgium; one Brewer spectrophotometer 128 and one sunphotometer CSEM SPM2000 at Norrköping in Sweden; and three Brewer instruments 040, 072, 156 at Arosa and one CSEM SPM2000 sunphotometer at Davos in Switzerland. The comparison between AODs from Brewer spectrophotometer 128 at 320.1 nm and sunphotometer SPM2000 at 368 nm at Norrköping shows that the AODs obtained from the Brewer measurements with the Langley Plot Method (LPM) are very accurate if the neutral density filter spectral transmittances are well known: with the measured values of these filters, the correlation coefficient, the slope, and the intercept of the regression line are 0.98, 0.85 ± 0.004, and 0.02 ± 0.0014, respectively. The bias observed is mainly owing to the wavelength difference between the two instruments. The comparison between AODs from different Brewer spectrophotometers confirm that AODs will be in very good agreement if they are measured with several Brewer instruments at the same place: At Uccle, the correlation coefficient, slope, and intercept of the regression line are 0.98, 1.02 ± 0.003, and 0.06 ± 0.001, respectively; at Arosa, the comparisons between the AODs from three Brewer spectrophotometers 040, 072, and 156 give a correlation coefficient, a slope, and an intercept of the regression line above 0.94, 0.98 and below 0.04, respectively.

Modeling Clinical Outcomes in Prostate Cancer: Application and Validation of the Discrete Event Simulation Approach.

PubMed

Pan, Feng; Reifsnider, Odette; Zheng, Ying; Proskorovsky, Irina; Li, Tracy; He, Jianming; Sorensen, Sonja V

2018-04-01

Treatment landscape in prostate cancer has changed dramatically with the emergence of new medicines in the past few years. The traditional survival partition model (SPM) cannot accurately predict long-term clinical outcomes because it is limited by its ability to capture the key consequences associated with this changing treatment paradigm. The objective of this study was to introduce and validate a discrete-event simulation (DES) model for prostate cancer. A DES model was developed to simulate overall survival (OS) and other clinical outcomes based on patient characteristics, treatment received, and disease progression history. We tested and validated this model with clinical trial data from the abiraterone acetate phase III trial (COU-AA-302). The model was constructed with interim data (55% death) and validated with the final data (96% death). Predicted OS values were also compared with those from the SPM. The DES model's predicted time to chemotherapy and OS are highly consistent with the final observed data. The model accurately predicts the OS hazard ratio from the final data cut (predicted: 0.74; 95% confidence interval [CI] 0.64-0.85 and final actual: 0.74; 95% CI 0.6-0.88). The log-rank test to compare the observed and predicted OS curves indicated no statistically significant difference between observed and predicted curves. However, the predictions from the SPM based on interim data deviated significantly from the final data. Our study showed that a DES model with properly developed risk equations presents considerable improvements to the more traditional SPM in flexibility and predictive accuracy of long-term outcomes. Copyright © 2018 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

The Effect of Exogenous Spermidine Concentration on Polyamine Metabolism and Salt Tolerance in Zoysiagrass (Zoysia japonica Steud) Subjected to Short-Term Salinity Stress.

PubMed

Li, Shucheng; Jin, Han; Zhang, Qiang

2016-01-01

Salt stress, particularly short-term salt stress, is among the most serious abiotic factors limiting plant survival and growth in China. It has been established that exogenous spermidine (Spd) stimulates plant tolerance to salt stress. The present study utilized two zoysiagrass cultivars commonly grown in China that exhibit either sensitive (cv. Z081) or tolerant (cv. Z057) adaptation capacity to salt stress. The two cultivars were subjected to 200 mM salt stress and treated with different exogenous Spd concentrations for 8 days. Polyamine [diamine putrescine (Put), tetraamine spermine (Spm), and Spd], H2O2 and malondialdehyde (MDA) contents and polyamine metabolic (ADC, ODC, SAMDC, PAO, and DAO) and antioxidant (superoxide dismutase, catalase, and peroxidase) enzyme activities were measured. The results showed that salt stress induced increases in Spd and Spm contents and ornithine decarboxylase (ODC), S-adenosylmethionine decarboxylase (SAMDC), and diamine oxidase (DAO) activities in both cultivars. Exogenous Spd application did not alter polyamine contents via regulation of polyamine-degrading enzymes, and an increase in polyamine biosynthetic enzyme levels was observed during the experiment. Increasing the concentration of exogenous Spd resulted in a tendency of the Spd and Spm contents and ODC, SAMDC, DAO, and antioxidant enzyme activities to first increase and then decrease in both cultivars. H2O2 and MDA levels significantly decreased in both cultivars treated with Spd. Additionally, in both cultivars, positive correlations between polyamine biosynthetic enzymes (ADC, SAMDC), DAO, and antioxidant enzymes (SOD, POD, CAT), but negative correlations with H2O2 and MDA levels, and the Spd + Spm content were observed with an increase in the concentration of exogenous Spd.

The Effect of Exogenous Spermidine Concentration on Polyamine Metabolism and Salt Tolerance in Zoysiagrass (Zoysia japonica Steud) Subjected to Short-Term Salinity Stress

PubMed Central

Li, Shucheng; Jin, Han; Zhang, Qiang

2016-01-01

Salt stress, particularly short-term salt stress, is among the most serious abiotic factors limiting plant survival and growth in China. It has been established that exogenous spermidine (Spd) stimulates plant tolerance to salt stress. The present study utilized two zoysiagrass cultivars commonly grown in China that exhibit either sensitive (cv. Z081) or tolerant (cv. Z057) adaptation capacity to salt stress. The two cultivars were subjected to 200 mM salt stress and treated with different exogenous Spd concentrations for 8 days. Polyamine [diamine putrescine (Put), tetraamine spermine (Spm), and Spd], H2O2 and malondialdehyde (MDA) contents and polyamine metabolic (ADC, ODC, SAMDC, PAO, and DAO) and antioxidant (superoxide dismutase, catalase, and peroxidase) enzyme activities were measured. The results showed that salt stress induced increases in Spd and Spm contents and ornithine decarboxylase (ODC), S-adenosylmethionine decarboxylase (SAMDC), and diamine oxidase (DAO) activities in both cultivars. Exogenous Spd application did not alter polyamine contents via regulation of polyamine-degrading enzymes, and an increase in polyamine biosynthetic enzyme levels was observed during the experiment. Increasing the concentration of exogenous Spd resulted in a tendency of the Spd and Spm contents and ODC, SAMDC, DAO, and antioxidant enzyme activities to first increase and then decrease in both cultivars. H2O2 and MDA levels significantly decreased in both cultivars treated with Spd. Additionally, in both cultivars, positive correlations between polyamine biosynthetic enzymes (ADC, SAMDC), DAO, and antioxidant enzymes (SOD, POD, CAT), but negative correlations with H2O2 and MDA levels, and the Spd + Spm content were observed with an increase in the concentration of exogenous Spd. PMID:27582752

Temporal occurrence and sources of persistent organic pollutants in suspended particulate matter from the most heavily polluted river mouth of Lake Chaohu, China.

PubMed

Liu, Cheng; Zhang, Lei; Fan, Chengxin; Xu, Fuliu; Chen, Kaining; Gu, Xiaozhi

2017-05-01

The Nanfei River is by many measures the most heavily polluted tributary to Lake Chaohu. In this study, the temporal occurrence and sources of four classes of persistent organic pollutants (POPs), including polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs), polybrominated diphenyl ethers (PBDEs), and polychlorinated biphenyls (PCBs), in suspended particulate matter (SPM) from the river mouth were investigated monthly during 2014. Results show that concentrations of all four POPs in SPM were higher than those in the sediment of Lake Chaohu. PBDEs (26.7 ng g -1 dry weight (dw)) were originated mainly from commercial deca-BDE mixtures. PCB concentrations (1.336 ng g -1 dw) were lower than those of sediments in many other water bodies worldwide. PAHs (2597 ng g -1 dw) and OCPs (57.38 ng g -1 dw) were the most common POPs. PAHs mainly had high molecular weights and originated from pyrolytic sources, with a small proportion of petrogenic origin. The predominant OCPs were DDTs, heptachlorepoxides, dieldrin, hexachlorocyclohexanes, hexachlorobenzene, and chlordanes. Most OCPs originated from historical use, except lindane. Generally, of all the POPs studied, those of primary ecological concern should be acenaphthene, fluorene, DDTs, and chlordanes. Higher concentrations of POPs were detected during winter and spring than in summer and autumn, probably because of the high river flow during the rainy season. The high concentration of POPs in the riverine SPM and the fractionation of POPs in the water and SPM of the river should be a focal point in the future study of Lake Chaohu. Copyright © 2017 Elsevier Ltd. All rights reserved.

Automatic voxel-based morphometry of structural MRI by SPM8 plus diffeomorphic anatomic registration through exponentiated lie algebra improves the diagnosis of probable Alzheimer Disease.

PubMed

Matsuda, H; Mizumura, S; Nemoto, K; Yamashita, F; Imabayashi, E; Sato, N; Asada, T

2012-06-01

The necessity for structural MRI is greater than ever to both diagnose AD in its early stage and objectively evaluate its progression. We propose a new VBM-based software program for automatic detection of early specific atrophy in AD. A target VOI was determined by group comparison of 30 patients with very mild AD and 40 age-matched healthy controls by using SPM. Then this target VOI was incorporated into a newly developed automated software program independently running on a Windows PC for VBM by using SPM8 plus DARTEL. ROC analysis was performed for discrimination of 116 other patients with AD with very mild stage (n = 45), mild stage (n = 30) and moderate-to-advanced stages (n = 41) from 40 other age-matched healthy controls by using a z score map in the target VOI. Medial temporal structures involving the entire region of the entorhinal cortex, hippocampus, and amygdala showed significant atrophy in the patients with very mild AD and were determined as a target VOI. When we used the severity score of atrophy in this target VOI, 91.6%, 95.8%, and 98.2% accuracies were obtained in the very mild AD, mild AD, and moderate-to-severe AD groups, respectively. In the very mild AD group, a high specificity of 97.5% with a sensitivity of 86.4% was obtained, and age at onset of AD did not influence this accuracy. This software program with application of SPM8 plus DARTEL to VBM provides a high performance for AD diagnosis by using MRI.

Chemical determination of particulate nitrogen in San Francisco Bay. Nitrogen: chlorophyll a rations in plankton

USGS Publications Warehouse

Hager, S.W.; Harmon, D.D.; Alpine, A.E.

1984-01-01

Particulate nitrogen (PN) and chlorophyll a (Chla) were measured in the northern reach of San Francisco Bay throughout 1980. The PN values were calculated as the differences between unfiltered and filtered (0·4 μm) samples analyzed using the UV-catalyzed peroxide digestion method. The Chla values were measured spectrophotometrically, with corrections made for phaeopigments. The plot of all PNChla data was found to be non-linear, and the concentration of suspended particulate matter (SPM) was found to be the best selector for linear subsets of the data. The best-fit slopes of PNChla plots, as determined by linear regression (model II), were interpreted to be the N: Chla ratios of phytoplankton. The Y-intercepts of the regression lines were considered to represent easily-oxidizable detrital nitrogen (EDN). In clear water ( < 10 mg l−1 SPM), the N: Chla ratio was 1·07 μg-at N per μg Chla. It decreased to 0·60 in the 10–18 mg l−1 range and averaged 0·31 in the remaining four ranges (18–35, 35–65, 65–155, and 155–470 mg l−1). The EDN values were less than 1 μg-at N l−1 in the clear water and increased monotonically to almost 12 μg-at N l−1 in the highest SPM range. The N: Chla ratios for the four highest SPM ranges agree well with data for phytoplankton in light-limited cultures. In these ranges, phytoplankton-N averaged only 20% of the PN, while EDN averaged 39% and refractory-N 41%.

A cluster of immunoresolvents links coagulation to innate host defense in human blood.

PubMed

Norris, Paul C; Libreros, Stephania; Chiang, Nan; Serhan, Charles N

2017-08-01

Blood coagulation is a protective response that prevents excessive bleeding upon blood vessel injury. We investigated the relationship between coagulation and the resolution of inflammation and infection by lipid mediators (LMs) through metabololipidomics-based profiling of human whole blood (WB) during coagulation. We identified temporal clusters of endogenously produced prothrombotic and proinflammatory LMs (eicosanoids), as well as specialized proresolving mediators (SPMs). In addition to eicosanoids, a specific SPM cluster was identified that consisted of resolvin E1 (RvE1), RvD1, RvD5, lipoxin B 4 , and maresin 1, each of which was present at bioactive concentrations (0.1 to 1 nM). Removal of adenosine from the coagulating blood markedly enhanced the amounts of SPMs produced and further increased the biosynthesis of RvD3, RvD4, and RvD6. The cyclooxygenase inhibitors celecoxib and indomethacin, which block the production of thromboxanes and prostanoids, did not block the production of clot-driven SPMs. Unbiased mass cytometry analysis demonstrated that the SPM cluster produced in human blood targeted leukocytes at the single-cell level, directly activating ERK and CREB signaling in neutrophils and CD14 + monocytes. Treatment of human WB with the components of this SPM cluster enhanced both the phagocytosis and killing of Escherichia coli by leukocytes. Together, these data identify a proresolving LM circuit, including endogenous molecular brakes and accelerators, which promoted host defense. These temporal LM-SPM clusters can provide accessible metabolomic profiles for precision and personalized medicine. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

Trace metals in suspended particles, sediments and Asiatic clams (Corbicula fluminea) of the Río de la Plata Estuary, Argentina.

PubMed

Bilos, C; Colombo, J C; Presa, M J

1998-01-01

Suspended particulate matter (SPM), sandy sediments and Asiatic clams were collected at seven sites along 150 km of the Río de la Plata coast to assess the magnitude of trace metal pollution in the area. Metal concentrations in SPM (Cu: 7.4-109; Cr: 75-408; Mn: 525-1341 microg(-1)), sediments (Cr: 16-27; Zn: 26-99; Mn: 221-489 microg(-1)) and bivalves (Cd: 0.5-1.9; Ni: 1.3-6.4; Cr: 1.3-11; Mn: 15-81; Cu: 28-89; Zn: 118-316 microg g(-1)) are comparable to those reported for other moderately polluted world rivers. Cu levels in Asiatic clams are among the highest, similar to those reported for heavily polluted sites. SPM Cu and Cr concentrations displayed a clear geographical trend with values increasing with proximity to major urban centers. Sediments showed a less clear pattern possibly due to their coarse nature (>98% sand) and higher proportion of mineral-associated residual metals. The clams showed a complex pattern due to the variability introduced by size-related factors and the natural dynamics of SPM in the estuary. Cr and Mn showed an apparent reverse industrial trend with higher concentrations in clams collected at distant stations near the turbidity maximum zone, possibly reflecting enhanced particle retention. Cu, Cd and Ni showed no clear geographical pattern, whereas Zn increased in the clams collected in the most industrialized area. A significant relationship with clam size was observed for Cu (positive) and Zn (negative) suggesting different physiological requirements for both metals with age. A principal component analysis confirmed these geographical and size-related trends.

Health risks of NO 2, SPM and SO 2 in Delhi (India)

NASA Astrophysics Data System (ADS)

Pandey, Jai Shanker; Kumar, Rakesh; Devotta, Sukumar

There is increasingly growing evidence linking urban air pollution to acute and chronic illnesses amongst all age groups. Therefore, monitoring of ambient concentrations of various air pollutants as well as quantification of the dose inhaled becomes quite important, specially in view of the fact that in many countries, policy decisions for reducing pollutant concentrations are mainly taken on the basis of their health impacts. The dose when gets combined with the likely responses, indicates the ultimate health risk (HR). Thus, as an extension of our earlier studies, HR has been estimated for three pollutants, namely, suspended particulate matter (SPM), nitrogen dioxide (NO 2) and sulfur dioxide (SO 2) for Delhi City in India. For estimation and analyses, three zones have been considered, namely, residential, industrial and commercial. The total population has been divided into three age classes (infants, children and adults) with different body weights and breathing rates. The exercise takes into account age-specific breathing rates, body weights for different age categories and occupancy factors for different zones. Results indicate that health risks due to air pollution in Delhi are highest for children. For all age categories, health risks due to SO 2 (HR_SO 2) are the lowest. Hence, HR_SO 2 has been taken as the reference with respect to which HR values due to SPM and NO 2 have been compared. Taking into account all the age categories and their occupancy in different zones, average HR values for NO 2 and SPM turn out to be respectively 22.11 and 16.13 times more than that for SO 2. The present study can be useful in generating public awareness as well as in averting and mitigating the health risks.

Heavy metal partitioning of suspended particulate matter-water and sediment-water in the Yangtze Estuary.

PubMed

Feng, Chenghong; Guo, Xiaoyu; Yin, Su; Tian, Chenhao; Li, Yangyang; Shen, Zhenyao

2017-10-01

The partitioning of ten heavy metals (As, Cd, Co, Cr, Cu, Hg, Ni, Pb, Sb, and Zn) between the water, suspended particulate matter (SPM), and sediments in seven channel sections during three hydrologic seasons in the Yangtze Estuary was comprehensively investigated. Special attention was paid to the role of tides, influential factors (concentrations of SPM and dissolved organic carbon, and particle size), and heavy metal speciation. The SPM-water and sediment-water partition coefficients (K p ) of the heavy metals exhibited similar changes along the channel sections, though the former were larger throughout the estuary. Because of the higher salinity, the K p values of most of the metals were higher in the north branch than in the south branch. The K p values of Cd, Co, and As generally decreased from the wet season to the dry season. Both the diagonal line method and paired samples t-test showed that no specific phase transfer of heavy metals existed during the flood and ebb tides, but the sediment-water K p was more concentrated for the diagonal line method, owing to the relatively smaller tidal influences on the sediment. The partition coefficients (especially the K p for SPM-water) had negative correlations with the dissolved organic carbon (DOC) but positive correlations were noted with the particle size for most of the heavy metals in sediment. Two types of significant correlations were observed between K p and metal speciation (i.e., exchangeable, carbonate, reducible, organic, and residual fractions), which can be used to identify the dominant phase-partition mechanisms (e.g., adsorption or desorption) of heavy metals. Copyright © 2017 Elsevier Ltd. All rights reserved.