Computational Investigation of Novel Tip Leakage Mitigation Methods for High Pressure Turbine Blades

Science.gov (United States)

Ibrahim, Mounir; Gupta, Abhinav; Shyam, Vikram

2014-01-01

This paper presents preliminary findings on a possible approach to reducing tip leakage losses. In this paper a computational study was conducted on the Energy Efficient Engine (EEE) High Pressure Turbine (HPT) rotor tip geometry using the commercial numerical solver ANSYS FLUENT. The flow solver was validated against aerodynamic data acquired in the NASA Transonic Turbine Blade Cascade facility. The scope of the ongoing study is to computationally investigate how the tip leakage and overall blade losses are affected by (1) injection from the tip near the pressure side, (2) injection from the tip surface at the camber line, and (3) injection from the tip surface into the tip separation bubble. The objective is to identify the locations on the tip surface at which to place appropriately configured blowing keeping in mind the film cooling application of tip blowing holes. The validation was conducted at Reynolds numbers of 85,000, 343,000, and 685,000 and at engine realistic flow conditions. The coolant injection simulations were conducted at a Reynolds number of 343,000 based on blade chord and inlet velocity and utilized the SST turbulence model in FLUENT. The key parameters examined are the number of jets, jet angle and jet location. A coolant to inlet pressure ratio of 1.0 was studied for angles of +30 deg, -30 deg, and 90 deg to the local free stream on the tip. For the 3 hole configuration, 3 holes spaced 3 hole diameters apart with length to diameter ratio of 1.5 were used. A simulation including 11 holes along the entire mean camber line is also presented (30 deg toward suction side). In addition, the effect of a single hole is also compared to a flat tip with no injection. The results provide insight into tip flow control methods and can be used to guide further investigation into tip flow control. As noted in past research it is concluded that reducing leakage flow is not necessarily synonymous with reducing losses due to leakage.

Towards easy and reliable AFM tip shape determination using blind tip reconstruction

International Nuclear Information System (INIS)

Flater, Erin E.; Zacharakis-Jutz, George E.; Dumba, Braulio G.; White, Isaac A.; Clifford, Charles A.

2014-01-01

Quantitative determination of the geometry of an atomic force microscope (AFM) probe tip is critical for robust measurements of the nanoscale properties of surfaces, including accurate measurement of sample features and quantification of tribological characteristics. Blind tip reconstruction, which determines tip shape from an AFM image scan without knowledge of tip or sample shape, was established most notably by Villarrubia [J. Res. Natl. Inst. Stand. Tech. 102 (1997)] and has been further developed since that time. Nevertheless, the implementation of blind tip reconstruction for the general user to produce reliable and consistent estimates of tip shape has been hindered due to ambiguity about how to choose the key input parameters, such as tip matrix size and threshold value, which strongly impact the results of the tip reconstruction. These key parameters are investigated here via Villarrubia's blind tip reconstruction algorithms in which we have added the capability for users to systematically vary the key tip reconstruction parameters, evaluate the set of possible tip reconstructions, and determine the optimal tip reconstruction for a given sample. We demonstrate the capabilities of these algorithms through analysis of a set of simulated AFM images and provide practical guidelines for users of the blind tip reconstruction method. We present a reliable method to choose the threshold parameter corresponding to an optimal reconstructed tip shape for a given image. Specifically, we show that the trend in how the reconstructed tip shape varies with threshold number is so regular that the optimal, or Goldilocks, threshold value corresponds with the peak in the derivative of the RMS difference with respect to the zero threshold curve vs. threshold number. - Highlights: • Blind tip reconstruction algorithms have been implemented and augmented to determine the optimal input parameters. • We demonstrate the capabilities of the algorithms using a simulated AFM

Single-step electrochemical method for producing very sharp Au scanning tunneling microscopy tips

International Nuclear Information System (INIS)

Gingery, David; Buehlmann, Philippe

2007-01-01

A single-step electrochemical method for making sharp gold scanning tunneling microscopy tips is described. 3.0M NaCl in 1% perchloric acid is compared to several previously reported etchants. The addition of perchloric acid to sodium chloride solutions drastically shortens etching times and is shown by transmission electron microscopy to produce very sharp tips with a mean radius of curvature of 15 nm

DC-pulsed voltage electrochemical method based on duty cycle self-control for producing TERS gold tips

International Nuclear Information System (INIS)

Vasilchenko, V E; Kharintsev, S S; Salakhov, M Kh

2013-01-01

This paper presents a modified dc-pulsed low voltage electrochemical method in which a duty cycle is self tuned while etching. A higher yield of gold tips suitable for performing tip-enhanced Raman scattering (TERS) measurements is demonstrated. The improvement is caused by the self-control of the etching rate along the full surface of the tip. A capability of the gold tips to enhance a Raman signal is exemplified by TERS spectroscopy of single walled carbon nanotubes bundle, sulfur and vanadium oxide

Twelve tips for facilitating Millennials' learning.

Science.gov (United States)

Roberts, David H; Newman, Lori R; Schwartzstein, Richard M

2012-01-01

The current, so-called "Millennial" generation of learners is frequently characterized as having deep understanding of, and appreciation for, technology and social connectedness. This generation of learners has also been molded by a unique set of cultural influences that are essential for medical educators to consider in all aspects of their teaching, including curriculum design, student assessment, and interactions between faculty and learners.  The following tips outline an approach to facilitating learning of our current generation of medical trainees.  The method is based on the available literature and the authors' experiences with Millennial Learners in medical training.  The 12 tips provide detailed approaches and specific strategies for understanding and engaging Millennial Learners and enhancing their learning.  With an increased understanding of the characteristics of the current generation of medical trainees, faculty will be better able to facilitate learning and optimize interactions with Millennial Learners.

A novel method for accurate needle-tip identification in trans-rectal ultrasound-based high-dose-rate prostate brachytherapy.

Science.gov (United States)

Zheng, Dandan; Todor, Dorin A

2011-01-01

In real-time trans-rectal ultrasound (TRUS)-based high-dose-rate prostate brachytherapy, the accurate identification of needle-tip position is critical for treatment planning and delivery. Currently, needle-tip identification on ultrasound images can be subject to large uncertainty and errors because of ultrasound image quality and imaging artifacts. To address this problem, we developed a method based on physical measurements with simple and practical implementation to improve the accuracy and robustness of needle-tip identification. Our method uses measurements of the residual needle length and an off-line pre-established coordinate transformation factor, to calculate the needle-tip position on the TRUS images. The transformation factor was established through a one-time systematic set of measurements of the probe and template holder positions, applicable to all patients. To compare the accuracy and robustness of the proposed method and the conventional method (ultrasound detection), based on the gold-standard X-ray fluoroscopy, extensive measurements were conducted in water and gel phantoms. In water phantom, our method showed an average tip-detection accuracy of 0.7 mm compared with 1.6 mm of the conventional method. In gel phantom (more realistic and tissue-like), our method maintained its level of accuracy while the uncertainty of the conventional method was 3.4mm on average with maximum values of over 10mm because of imaging artifacts. A novel method based on simple physical measurements was developed to accurately detect the needle-tip position for TRUS-based high-dose-rate prostate brachytherapy. The method demonstrated much improved accuracy and robustness over the conventional method. Copyright © 2011 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

Alar setback technique: a controlled method of nasal tip deprojection.

Science.gov (United States)

Foda, H M

2001-11-01

To describe an alar cartilage-modifying technique aimed at decreasing nasal tip projection in cases with overdeveloped alar cartilages and to compare it with other deprojection techniques used to correct such deformity. Selected case series. University and private practice settings in Alexandria, Egypt. Twenty patients presenting for rhinoplasty who had overprojected nasal tips primarily due to overdeveloped alar cartilages. All cases were primary cases except for one patient, who had undergone 2 previous rhinoplasties. An external rhinoplasty approach was used to set back the alar cartilages by shortening their medial and lateral crura. The choice of performing a high or low setback depended on the preexisting lobule-to-columella ratio. Following the setback, the alar cartilages were reconstructed in a fashion that increased the strength and stability of the tip complex. Subjective evaluation included clinical examination, analysis of preoperative and postoperative photographs, and patient satisfaction. Objective evaluation of nasal tip projection, using the Goode ratio and the nasofacial angle, was performed preoperatively and repeated at least 6 months postoperatively. A low setback was performed in 16 cases (80%) and a high setback in 4 (20%). The mean follow-up period was 18 months (range, 6-36 months). The technique effectively deprojected the nasal tip as evidenced by the considerable postoperative decrease in values of the Goode ratio and the nasofacial angle. No complications were encountered and no revision surgical procedures were required. The alar setback technique has many advantages; it results in precise predictable amounts of deprojection, controls the degree of tip rotation, preserves the natural contour of the nasal tip, respects the tip support mechanisms, increases the strength and stability of nasal tip complex, preserves or restores the normal lobule-to-columella proportion, and does not lead to alar flaring. However, the technique requires

In-vitro morphogenesis of corn (Zea mays L.) : I. Differentiation of multiple shoot clumps and somatic embryos from shoot tips.

Science.gov (United States)

Zhong, H; Srinivasan, C; Sticklen, M B

1992-07-01

In-vitro methods have been developed to regenerate clumps of multiple shoots and somatic embryos at high frequency from shoot tips of aseptically-grown seedlings as well as from shoot apices of precociously-germinated immature zygotic embryos of corn (Zea mays L.). About 500 shoots were produced from a shoot tip after eight weeks of culture (primary culture and one subculture of four weeks) in darkness on Murashige and Skoog basal medium (MS) supplemented with 500 mg/L casein hydrolysate (CH) and 9 μM N(6)-benzyladenine (BA). In this medium, shoots formed in shoot tips as tightly packed "multiple shoot clumps" (MSC), which were composed of some axillary shoots and many adventitious shoots. When the shoot tips were cultured on MS medium containing 500 mg/L CH, 9 μM BA and 2.25 μM 2,4-dichlorophenoxyacetic acid (2,4-D), most of the shoots in the clumps were adventitious in origin. Similar shoot tips cultured on MS medium containing 500 mg/L CH, 4.5 μM BA and 2.25 μM 2,4-D regenerated many somatic embryos within eight weeks of culture. Somatic embryos were produced either directly from the shoot apical meristems or from calli derived from the shoots apices. Both the MSC and the embryos produced normal shoots on MS medium containing 2.25 μM BA and 1.8 μM indole-3-butyric acid (IBA). These shoots were rooted on MS medium containing 3.6 μM IBA, and fertile corn plants were grown in the greenhouse. The sweet-corn genotype, Honey N Pearl, was used for the experiments described above, but shoot-tip cultures from all of 19 other corn genotypes tested also formed MSC on MS medium containing 500 mg/L CH and 9 μM BA.

Chemically etched fiber tips for near-field optical microscopy: a process for smoother tips.

Science.gov (United States)

Lambelet, P; Sayah, A; Pfeffer, M; Philipona, C; Marquis-Weible, F

1998-11-01

An improved method for producing fiber tips for scanning near-field optical microscopy is presented. The improvement consists of chemically etching quartz optical fibers through their acrylate jacket. This new method is compared with the previous one in which bare fibers were etched. With the new process the meniscus formed by the acid along the fiber does not move during etching, leading to a much smoother surface of the tip cone. Subsequent metallization is thus improved, resulting in better coverage of the tip with an aluminum opaque layer. Our results show that leakage can be avoided along the cone, and light transmission through the tip is spatially limited to an optical aperture of a 100-nm dimension.

Efficient regeneration of plants from shoot tip explants of ...

African Journals Online (AJOL)

Dendrobium densiflorum Lindl. is one of the horticulturally important orchids of Nepal due to its beautiful yellowish flower and medicinal properties. The present study was carried out for plant regeneration from shoot tip explants of D. densiflorum by tissue culture technique. The shoot tip explants of this species, obtained ...

Influence of the tip mass on the tip-sample interactions in TM-AFM

Energy Technology Data Exchange (ETDEWEB)

Pishkenari, Hossein Nejat, E-mail: nejat@mech.sharif.edu [Nano-Robotics Laboratory, Center of Excellence in Design, Robotics and Automation, School of Mechanical Engineering, Sharif University of Technology, Tehran, P.O. Box 11365-9465 (Iran, Islamic Republic of); Meghdari, Ali [Nano-Robotics Laboratory, Center of Excellence in Design, Robotics and Automation, School of Mechanical Engineering, Sharif University of Technology, Tehran, P.O. Box 11365-9465 (Iran, Islamic Republic of)

2011-07-15

This paper focuses on the influences of the tip mass ratio (the ratio of the tip mass to the cantilever mass), on the excitation of higher oscillation eigenmodes and also on the tip-sample interaction forces in tapping mode atomic force microscopy (TM-AFM). A precise model for the cantilever dynamics capable of accurate simulations is essential for the investigation of the tip mass effects on the interaction forces. In the present work, the finite element method (FEM) is used for modeling the AFM cantilever to consider the oscillations of higher eigenmodes oscillations. In addition, molecular dynamics (MD) is used to calculate precise data for the tip-sample force as a function of tip vertical position with respect to the sample. The results demonstrate that in the presence of nonlinear tip-sample interaction forces, the tip mass ratio plays a significant role in the excitations of higher eigenmodes and also in the normal force applied on the surface. Furthermore, it has been shown that the difference between responses of the FEM and point-mass models in different system operational conditions is highly affected by the tip mass ratio. -- Highlights: {yields} A strong correlation exists between the tip mass ratio and the 18th harmonic amplitude. {yields} Near the critical tip mass ratio a small change in the tip mass may lead to a significant force change. {yields} Inaccuracy of the lumped model depends significantly on the tip mass ratio.

Methods for Cavitation Prediction on Tip-Modified Propellers in Ship Wake Fields

DEFF Research Database (Denmark)

Shin, Keun Woo; Regener, Pelle Bo; Andersen, Poul

2015-01-01

Unsteady cavitation simulations on a tip-modified propellerin behind-hull condition are made by both BoundaryElement Method (BEM) and Computational FluidDynamics (CFD).As the hull geometry typically is not disclosed to thepropeller designer and thus cannot be included in thesimulation, other meas...

Effects of AFM tip-based direct and vibration assisted scratching methods on nanogrooves fabrication on a polymer resist

Energy Technology Data Exchange (ETDEWEB)

Geng, Yanquan [The State Key Laboratory of Robotics and Systems, Robotics Institute, Harbin Institute of Technology, Harbin, Heilongjiang 150080 (China); Center for Precision Engineering, Harbin Institute of Technology, Harbin, Heilongjiang 150001 (China); Yan, Yongda, E-mail: yanyongda@hit.edu.cn [The State Key Laboratory of Robotics and Systems, Robotics Institute, Harbin Institute of Technology, Harbin, Heilongjiang 150080 (China); Center for Precision Engineering, Harbin Institute of Technology, Harbin, Heilongjiang 150001 (China); Zhuang, Yun; Hu, Zhenjiang [Center for Precision Engineering, Harbin Institute of Technology, Harbin, Heilongjiang 150001 (China)

2015-11-30

Graphical abstract: - Highlights: • The comparison of three different atomic force microscope (AFM) tip-based material processing techniques to generate nano-grooves on polymethylmethacrylate (PMMA) thin film is presented. • The machined depths of the nano-grooves machined by these three methods are analyzed. • Nano-groove with the machined depth closed to the thickness of the thin-film resist is achieved. - Abstract: This study proposes two atomic force microscope (AFM) tip-based direct nanoscratching methods including single-pass scratching and multi-pass scratching compared with a vibration-assisted scratching method to fabricate nano-grooves on the surface of the polymethylmethacrylate (PMMA) thin-film resist. In order to protect the AFM tip from wearing and optimize the subsequent etching process, the machined depth is expected slightly less than the PMMA thickness to prevent the tip directly contacting with the silicon substrate and obtain better process results. First, single-pass scratching tests are performed on films with different thickness employing varied normal loads. Results show that the machined depths of the grooves cannot be obtained slightly less than the thickness of the film very easily when scratching with single-pass method, 50–120 nm in the present study, which may not be very suitable for the following etching process. Multi-pass and vibration-assisted methods are then utilized to solve this limitation of the machined depth in single-pass process. The machined depths using the multi-pass method are dependent on scratching times and the applied normal loads. Moreover, the depth closed to the thickness of the film can be obtained by enlarging the number of the scratching cycles. However, with a longer scratching time, large tip wear can be found. For vibration assisted method, the machined depths are controlled by the vibration amplitude and the applied normal load. With the vibration in z direction increasing, the machined depth can

Bacterial Contamination in Tips of Electrocautery Devices During Total Hip Arthroplasty.

Science.gov (United States)

Shahi, Alisina; Chen, Antonia F; McKenna, Paul B; Roberts, Amity L; Manrique, Jorge; Belden, Katherine A; Austin, Matthew S

2015-08-01

Surgical equipment can become contaminated during surgery. It is unknown if electrocautery tips can become contaminated in clean orthopedic procedures despite the produced heat. Therefore, we conducted a prospective study to address this concern. The tips from 25 primary and 25 aseptic revision THAs were collected and an additional 5 sterile tips served as negative controls. Aerobic and anaerobic cultures were incubated for a minimum of 3 days. There were 3 positive cultures (6%); one in primary THA (4%) with Lactobacillus and Enterococcus faecalis; two among revisions (8%), one with E. faecalis and another one with alpha hemolytic streptococci and coagulase negative Staphylococcus. The mean exposure time of the contaminated tips was 132.3 minutes. Patients were followed for 90 days postoperatively and none of them developed surgical site infection. This is the first study to demonstrate that electrosurgical devices can become contaminated during THA in laminar flow equipped operating rooms. Copyright © 2015 Elsevier Inc. All rights reserved.

Frequency of colonization and isolated bacteria from the tip of epidural catheter implanted for postoperative analgesia.

Science.gov (United States)

Stabille, Débora Miranda Diogo; Diogo Filho, Augusto; Mandim, Beatriz Lemos da Silva; de Araújo, Lúcio Borges; Mesquita, Priscila Miranda Diogo; Jorge, Miguel Tanús

2015-01-01

The increased use of epidural analgesia with catheter leads to the need to demonstrate the safety of this method and know the incidence of catheter colonization, inserted postoperatively for epidural analgesia, and the bacteria responsible for this colonization. From November 2011 to April 2012, patients electively operated and maintained under epidural catheter for postoperative analgesia were evaluated. The catheter tip was collected for semiquantitative and qualitative microbiological analysis. Of 68 cultured catheters, six tips (8.8%) had positive cultures. No patient had superficial or deep infection. The mean duration of catheter use was 43.45 h (18-118) (p=0.0894). The type of surgery (contaminated or uncontaminated), physical status of patients, and surgical time showed no relation with the colonization of catheters. Microorganisms isolated from the catheter tip were Staphylococcus aureus, Pseudomonas aeruginosa and Sphingomonas paucimobilis. Postoperative epidural catheter analgesia, under these study conditions, was found to be low risk for bacterial colonization in patients at surgical wards. Copyright © 2014 Sociedade Brasileira de Anestesiologia. Published by Elsevier Editora Ltda. All rights reserved.

Eight piece quadrupole magnet, method for aligning quadrupole magent pole tips

Science.gov (United States)

Jaski, Mark S.; Liu, Jie; Donnelly, Aric T.; Downey, Joshua S.; Nudell, Jeremy J.; Jain, Animesh

2018-01-30

The invention provides an alternative to the standard 2-piece or 4-piece quadrupole. For example, an 8-piece and a 10-piece quadrupole are provided whereby the tips of each pole may be adjustable. Also provided is a method for producing a quadrupole using standard machining techniques but which results in a final tolerance accuracy of the resulting construct which is better than that obtained using standard machining techniques.

Direct calculation of wind turbine tip loss

DEFF Research Database (Denmark)

Wood, D.H.; Okulov, Valery; Bhattacharjee, D.

2016-01-01

. We develop three methods for the direct calculation of the tip loss. The first is the computationally expensive calculation of the velocities induced by the helicoidal wake which requires the evaluation of infinite sums of products of Bessel functions. The second uses the asymptotic evaluation......The usual method to account for a finite number of blades in blade element calculations of wind turbine performance is through a tip loss factor. Most analyses use the tip loss approximation due to Prandtl which is easily and cheaply calculated but is known to be inaccurate at low tip speed ratio...

Twelve tips for getting started using mixed methods in medical education research.

Science.gov (United States)

Lavelle, Ellen; Vuk, Jasna; Barber, Carolyn

2013-04-01

Mixed methods research, which is gaining popularity in medical education, provides a new and comprehensive approach for addressing teaching, learning, and evaluation issues in the field. The aim of this article is to provide medical education researchers with 12 tips, based on consideration of current literature in the health professions and in educational research, for conducting and disseminating mixed methods research. Engaging in mixed methods research requires consideration of several major components: the mixed methods paradigm, types of problems, mixed method designs, collaboration, and developing or extending theory. Mixed methods is an ideal tool for addressing a full range of problems in medical education to include development of theory and improving practice.

[Frequency of colonization and isolated bacteria from the tip of the epidural catheter implanted for postoperative analgesia].

Science.gov (United States)

Stabille, Débora Miranda Diogo; Filho, Augusto Diogo; Mandim, Beatriz Lemos da Silva; Araújo, Lúcio Borges de; Mesquita, Priscila Miranda Diogo; Jorge, Miguel Tanús

2015-01-01

The increased use of epidural analgesia with catheter leads to the need to demonstrate the safety of this method and know the incidence of catheter colonization, inserted postoperatively for epidural analgesia, and the bacteria responsible for this colonization. From November 2011 to April 2012, patients electively operated and maintained under epidural catheter for postoperative analgesia were evaluated. The catheter tip was collected for semiquantitative and qualitative microbiological analysis. Of 68 cultured catheters, six tips (8.8%) had positive cultures. No patient had superficial or deep infection. The mean duration of catheter use was 43.45hours (18-118) (p=0.0894). The type of surgery (contaminated or uncontaminated), physical status of patients, and surgical time showed no relation with the colonization of catheters. Microorganisms isolated from the catheter tip were Staphylococcus aureus, Pseudomonas aeruginosa and Sphingomonas paucimobilis. Postoperative epidural catheter analgesia, under this study conditions, was found to be low risk for bacterial colonization in patients at surgical wards. Copyright © 2014 Sociedade Brasileira de Anestesiologia. Publicado por Elsevier Editora Ltda. All rights reserved.

Discussion of the Improved Methods for Analyzing a Cantilever Beam Carrying a Tip-Mass under Base Excitation

Directory of Open Access Journals (Sweden)

Wang Hongjin

2014-01-01

Full Text Available Two improved analytical methods of calculations for natural frequencies and mode shapes of a uniform cantilever beam carrying a tip-mass under base excitation are presented based on forced vibration theory and the method of separation of variables, respectively. The cantilever model is simplified in detail by replacing the tip-mass with an equivalent inertial force and inertial moment acting at the free end of the cantilever based on D’Alembert’s principle. The concentrated equivalent inertial force and inertial moment are further represented as distributed loads using Dirac Delta Function. In this case, some typical natural frequencies and mode shapes of the cantilever model are calculated by the improved and unimproved analytical methods. The comparing results show that, after improvement, these two methods are in extremely good agreement with each other even the offset distance between the gravity center of the tip-mass and the attachment point is large. As further verification, the transient and steady displacement responses of the cantilever system under a sine base excitation are presented in which two improved methods are separately utilized. Finally, an experimental cantilever system is fabricated and the theoretical displacement responses are validated by the experimental measurements successfully.

Tip studies using CFD and comparison with tip loss models

DEFF Research Database (Denmark)

Hansen, Martin Otto Laver; Johansen, J.

2004-01-01

The flow past a rotating LM8.2 blade equipped with two different tips are computed using CFD. The different tip flows are analysed and a comparison with two different tip loss models is made. Keywords: tip flow, aerodynamics, CFD......The flow past a rotating LM8.2 blade equipped with two different tips are computed using CFD. The different tip flows are analysed and a comparison with two different tip loss models is made. Keywords: tip flow, aerodynamics, CFD...

Hard-tip, soft-spring lithography.

Science.gov (United States)

Shim, Wooyoung; Braunschweig, Adam B; Liao, Xing; Chai, Jinan; Lim, Jong Kuk; Zheng, Gengfeng; Mirkin, Chad A

2011-01-27

Nanofabrication strategies are becoming increasingly expensive and equipment-intensive, and consequently less accessible to researchers. As an alternative, scanning probe lithography has become a popular means of preparing nanoscale structures, in part owing to its relatively low cost and high resolution, and a registration accuracy that exceeds most existing technologies. However, increasing the throughput of cantilever-based scanning probe systems while maintaining their resolution and registration advantages has from the outset been a significant challenge. Even with impressive recent advances in cantilever array design, such arrays tend to be highly specialized for a given application, expensive, and often difficult to implement. It is therefore difficult to imagine commercially viable production methods based on scanning probe systems that rely on conventional cantilevers. Here we describe a low-cost and scalable cantilever-free tip-based nanopatterning method that uses an array of hard silicon tips mounted onto an elastomeric backing. This method-which we term hard-tip, soft-spring lithography-overcomes the throughput problems of cantilever-based scanning probe systems and the resolution limits imposed by the use of elastomeric stamps and tips: it is capable of delivering materials or energy to a surface to create arbitrary patterns of features with sub-50-nm resolution over centimetre-scale areas. We argue that hard-tip, soft-spring lithography is a versatile nanolithography strategy that should be widely adopted by academic and industrial researchers for rapid prototyping applications.

Development of new tip-loss corrections based on vortex theory and vortex methods

DEFF Research Database (Denmark)

Branlard, Emmanuel Simon Pierre; Gaunaa, Mac

2014-01-01

A new analytical formulation of the tip-loss factor is established based on helical vortex lament solutions. The derived tip-loss factor can be applied to wind-turbines, propellers or other rotary wings. Similar numerical formulations are used to assess the influence of wake expansion on tip...

Structural properties 3,16-bis triisopropylsilylethynyl (pentacene) (TIPS-pentacene) thin films onto organic dielectric layer using slide coating method

Energy Technology Data Exchange (ETDEWEB)

Rusnan, Fara Naila; Mohamad, Khairul Anuar; Seria, Dzul Fahmi Mohd Husin; Saad, Ismail; Ghosh, Bablu K.; Alias, Afishah [Nano Engineering & Materials (NEMs) Research Group, Faculty of Engineering Universiti Malaysia Sabah, Kota Kinabalu 88400 Sabah (Malaysia)

2015-08-28

3,16-bis triisopropylsilylethynyl (Pentacene) (TIPS-Pentacene) compactable interface property is important in order to have a good arrangement of molecular structure. Comparison for TIPS-Pentacene deposited between two different surface layers conducted. 0.1wt% TIPS-Pentacene diluted in chloroform were deposited onto poly(methylmeaclyrate) (PMMA) layered transparent substrates using slide coating method. X-ray diffraction (XRD) used to determine crystallinity of thin films. Series of (00l) diffraction peaks obtained with sharp first peaks (001) for TIPS-Pentacene deposited onto PMMA layer at 5.35° and separation of 16.3 Å. Morphology and surface roughness were carried out using scanning electron microscope (SEM) and surface profilemeter LS500, respectively.TIPS-Pentacene deposited onto PMMA layer formed needled-like-shape grains with 10.26 nm surface roughness. These properties were related as thin film formed and its surface roughness plays important role towards good mobility devices.

Method of mechanical holding of cantilever chip for tip-scan high-speed atomic force microscope

Energy Technology Data Exchange (ETDEWEB)

Fukuda, Shingo [Department of Physics, College of Science and Engineering, Kanazawa University, Kakuma-machi, Kanazawa 920-1192 (Japan); Uchihashi, Takayuki; Ando, Toshio [Department of Physics, College of Science and Engineering, Kanazawa University, Kakuma-machi, Kanazawa 920-1192 (Japan); Bio-AFM Frontier Research Center, College of Science and Engineering, Kanazawa University, Kakuma-machi, Kanazawa 920-1192 (Japan); Core Research for Evolutional Science and Technology of the Japan Science and Technology Agency, 7 Goban-cho, Chiyoda-ku, Tokyo 102-0076 (Japan)

2015-06-15

In tip-scan atomic force microscopy (AFM) that scans a cantilever chip in the three dimensions, the chip body is held on the Z-scanner with a holder. However, this holding is not easy for high-speed (HS) AFM because the holder that should have a small mass has to be able to clamp the cantilever chip firmly without deteriorating the Z-scanner’s fast performance, and because repeated exchange of cantilever chips should not damage the Z-scanner. This is one of the reasons that tip-scan HS-AFM has not been established, despite its advantages over sample stage-scan HS-AFM. Here, we present a novel method of cantilever chip holding which meets all conditions required for tip-scan HS-AFM. The superior performance of this novel chip holding mechanism is demonstrated by imaging of the α{sub 3}β{sub 3} subcomplex of F{sub 1}-ATPase in dynamic action at ∼7 frames/s.

Light depolarization induced by metallic tips in apertureless near-field optical microscopy and tip-enhanced Raman spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Gucciardi, P G [CNR-Istituto per i Processi Chimico-Fisici, sezione Messina, Salita Sperone, Contrada Papardo, I-98158 Faro Superiore, Messina (Italy); Lopes, M; Deturche, R; Julien, C; Barchiesi, D; Chapelle, M Lamy de la [Institut Charles Delaunay-CNRS FRE 2848, Laboratoire de Nanotechnologie et d' Instrumentation Optique, Universite de Technologie de Troyes, 12 rue Marie Curie, BP2060, 10010 Troyes (France)

2008-05-28

We have investigated the depolarization effects of light scattered by sharp tips used for apertureless near-field optical microscopy. Dielectric and metal coated tips have been investigated and depolarization factors between 5 and 30% have been measured, changing as a function of the incident light polarization and of the tip shape. The experimental results are in good agreement with theoretical calculations performed by the finite element method, giving a near-field depolarization factor close to 10%. The effect of depolarization has been investigated in polarized tip-enhanced Raman spectroscopy (TERS) experiments; the depolarization gives rise to forbidden Raman modes in Si crystals.

Rapid in vitro propagation system through shoot tip cultures of Vitex trifolia L.-an important multipurpose plant of the Pacific traditional Medicine.

Science.gov (United States)

Ahmed, Rafique; Anis, Mohammad

2014-07-01

A rapid and efficient plant propagation system through shoot tip explants was established in Vitex trifolia L., a medicinally important plant belonging to the family Verbenaceae. Multiple shoots were induced directly on Murashige and Skoog (MS) medium consisting of different cytokinins, 6-benzyladenine (BA), kinetin (Kin) and 2-isopentenyl adenine (2-iP), BA at an optimal concentration of 5.0 μM was most effective in inducing multiple shoots where 90 % explants responded with an average shoot number (4.4±0.1) and shoot length (2.0±0.1 cm) after 6 weeks of culture. Inclusion of NAA in the culture medium along with the optimum concentration of BA promoted a higher rate of shoot multiplication and length of the shoot, where 19.2±0.3 well-grown healthy shoots with an average shoot length of 4.4±0.1 cm were obtained on completion of 12 weeks culture period. Ex vitro rooting was achieved best directly in soilrite when basal portion of the shoots were treated with 500 μM indole-3-butyric acid for 15 min which was the most effective in inducing roots, as 95 % of the microshoots produced roots. Plantlets went through a hardening phase in a controlled plant growth chamber, prior to ex-vitro transfer. Micropropagated plants grew well, attained maturity and flowered with 92 % survival rate. The results of this study provide the first report on in vitro plant regeneration of Vitex trifolia L. using shoot tip explants.

Aerodynamic characteristics of a wing near its tip using panel method. Panel ho ni yoru tandokuyoku yokutan fukin no kuryoku tokusei

Energy Technology Data Exchange (ETDEWEB)

Choi, J [Nagoya University, Nagoya (Japan); Sugiyama, Y [Nagoya University, Nagoya (Japan). Faculty of Engineering

1992-01-05

The study described in this paper is intended to evaluate the aerodynamic characteristics of a turbo machine wing or an aircraft wing near its tip, using the panel method. The paper describes the case of a rectangular wing with a large aspect ratio. The introduced linear simultaneous equation was solved using a computer, and compared with the experimental result. The result may be summarized as follows: The distribution of pressure on the wing near its tip using the panel method takes the same shape as that for the experimental result; the negative pressure calculated close to the wing's trailing edge near the wing tip is a result of a three-dimensional effect of the flow along the wing width; the calculation and the experiment showed an increase in local lift coefficient and locally induced resistance coefficient in the vicinity of wing tip; the speed component in the y'' direction explains the structure of the wing surface velocity forming wing backwash vortex given by the lift linearity theory; and the result of calculation on the pressure distribution in the wing chord direction near the wing tip is very close to the experimental result except for the wing flank in the close vicinity of the wing tip upstream of the wing chord middle point. 11 refs., 13 figs.

AFM tip characterization by using FFT filtered images of step structures

Energy Technology Data Exchange (ETDEWEB)

Yan, Yongda, E-mail: yanyongda@hit.edu.cn [Key Laboratory of Micro-systems and Micro-structures Manufacturing of Ministry of Education, Harbin Institute of Technology, Harbin, Heilongjiang 150001 (China); Center For Precision Engineering, Harbin Institute of Technology, Harbin, Heilongjiang 150001 (China); Xue, Bo [Key Laboratory of Micro-systems and Micro-structures Manufacturing of Ministry of Education, Harbin Institute of Technology, Harbin, Heilongjiang 150001 (China); Center For Precision Engineering, Harbin Institute of Technology, Harbin, Heilongjiang 150001 (China); Hu, Zhenjiang; Zhao, Xuesen [Center For Precision Engineering, Harbin Institute of Technology, Harbin, Heilongjiang 150001 (China)

2016-01-15

The measurement resolution of an atomic force microscope (AFM) is largely dependent on the radius of the tip. Meanwhile, when using AFM to study nanoscale surface properties, the value of the tip radius is needed in calculations. As such, estimation of the tip radius is important for analyzing results taken using an AFM. In this study, a geometrical model created by scanning a step structure with an AFM tip was developed. The tip was assumed to have a hemispherical cone shape. Profiles simulated by tips with different scanning radii were calculated by fast Fourier transform (FFT). By analyzing the influence of tip radius variation on the spectra of simulated profiles, it was found that low-frequency harmonics were more susceptible, and that the relationship between the tip radius and the low-frequency harmonic amplitude of the step structure varied monotonically. Based on this regularity, we developed a new method to characterize the radius of the hemispherical tip. The tip radii estimated with this approach were comparable to the results obtained using scanning electron microscope imaging and blind reconstruction methods. - Highlights: • The AFM tips with different radii were simulated to scan a nano-step structure. • The spectra of the simulation scans under different radii were analyzed. • The functions of tip radius and harmonic amplitude were used for evaluating tip. • The proposed method has been validated by SEM imaging and blind reconstruction.

Transcaval TIPS in patients with failed revision of occluded previous TIPS

Energy Technology Data Exchange (ETDEWEB)

Seong, Chang Kyu; Kim, Yong Joo; Shin, Tae Beom; Park, Hyo Yong; Kim, Tae Hun; Kang, Duk Sik [Kyungpook National University School of Medicine, Daegu (Korea, Republic of)

2001-12-01

To determine the feasibility of transcaval transjugular intrahepatic portosystemic shunt (TIPS) in patients with occluded previous TIPS. Between February 1996 and December 2000 we performed five transcaval TIPS procedures in four patients with recurrent gastric cardiac variceal bleeding. All four had occluded TIPS, which was between the hepatic and portal vein. The interval between initial TIPS placement and revisional procedures with transcaval TIPS varied between three and 31 months; one patient underwent transcaval TIPS twice, with a 31-month interval. After revision of the occluded shunt failed, direct cavoportal puncture at the retrohepatic segment of the IVC was attempted. Transcaval TIPS placement was technically successful in all cases. In three, tractography revealed slight leakage of contrast materials into hepatic subcapsular or subdiaphragmatic pericaval space. There was no evidence of propagation of extravasated contrast materials through the retroperitoneal space or spillage into the peritoneal space. After the tract was dilated by a bare stent, no patient experienced trans-stent bleeding and no serious procedure-related complications occurred. After successful shunt creation, variceal bleeding ceased in all patients. Transcaval TIPS placement is an effective and safe alternative treatment in patients with occluded previous TIPS and no hepatic veins suitable for new TIPS.

Tipping Point

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Full Text Available ... en español Blog About OnSafety CPSC Stands for Safety The Tipping Point Home > 60 Seconds of Safety (Videos) > The Tipping Point The Tipping Point by ... danger death electrical fall furniture head injury product safety television tipover tv Watch the video in Adobe ...

Modification of AFM Tips for Facilitating Picking-up of Nanoparticles

International Nuclear Information System (INIS)

Peng, Wang; Hai-Jun, Yang; Hua-Bin, Wang; Hai, Li; Xin-Yan, Wang; Ying, Wang; Jun-Hong, Lü; Bin, Li; Yi, Zhang; Jun, Hu

2008-01-01

The radius of atomic force microscope (AFM) tip is a key factor that influences nonspecific interactions between AFM tip and nanoparticles. Generally, a tip with larger radius contributes to a higher efficiency of picking up nanoparticles. We provide two methods for modifying the AFM tip: one is to wear a tip apex on a solid substrate and the other is to coat a tip with poly (dimethylsiloxane) (PDMS). Both the approaches can enhance the adhesion force between the tip and nanoparticles by increasing tip radius. The experimental results show that a modified tip, compared to an unmodified one, achieves six-fold efficiency improvement in the capture of targeted colloidal gold nanoparticles. (general)

Numerical investigation of three wind turbine blade tips

Energy Technology Data Exchange (ETDEWEB)

Johansen, J.; Soerensen, N.N.

2002-08-01

The complex three-dimensional flow around three different tip shapes on a rotating wind turbine blade is investigated and analyzed using Computational Fluid Dynamics. Differences in production, flap wise bending moments and forces are discussed. A method for determining the local inflow angle of attack is presented and further analysis is performed on lift and drag coefficients. It is shown that the original Standard tip results in a more concentrated tip vortex leading to a steeper gradient on both tangential and normal forces when approaching the tip, whereas the two tapered tips show a more flat behavior. This again leads to lower flap wise bending moments and lower production for the Standard tip compared to the two tapered tips. At 12 m/s, though, the Swept tip shows a separation pattern on the surface. This separation causes a decrease in normal force and an increase in tangential force. The Taper tip keeps the higher loading causing the flap wise bending moment to be higher as seen in measurements. To determine the radial variation of lift and drag coefficients the local inflow angle of attack is determined. It is shown that the Standard tip experiences a slightly larger angle of attack at the tip compared to the two tapered tips. The lift coefficients are kept at a more constant level for the two tapered tips due to the decrease in chord, while the drag coefficients actually decrease for the two tapered tips, especially for the Swept tip. For the Swept tip at 12 m/s both lift and drag coefficients changed considerably due to the separation. Differences in aerodynamic damping of the three tips were investigated using HAWCDAMP. The Standard tip seems to be slightly less damped with respect to the edgewise vibrations. (au)

Dynamic of cold-atom tips in anharmonic potentials

Science.gov (United States)

Menold, Tobias; Federsel, Peter; Rogulj, Carola; Hölscher, Hendrik; Fortágh, József

2016-01-01

Background: Understanding the dynamics of ultracold quantum gases in an anharmonic potential is essential for applications in the new field of cold-atom scanning probe microscopy. Therein, cold atomic ensembles are used as sensitive probe tips to investigate nanostructured surfaces and surface-near potentials, which typically cause anharmonic tip motion. Results: Besides a theoretical description of this anharmonic tip motion, we introduce a novel method for detecting the cold-atom tip dynamics in situ and real time. In agreement with theory, the first measurements show that particle interactions and anharmonic motion have a significant impact on the tip dynamics. Conclusion: Our findings will be crucial for the realization of high-sensitivity force spectroscopy with cold-atom tips and could possibly allow for the development of advanced spectroscopic techniques such as Q-control. PMID:28144505

A new method for automated dynamic calibration of tipping-bucket rain gauges

Science.gov (United States)

Humphrey, M.D.; Istok, J.D.; Lee, J.Y.; Hevesi, J.A.; Flint, A.L.

1997-01-01

Existing methods for dynamic calibration of tipping-bucket rain gauges (TBRs) can be time consuming and labor intensive. A new automated dynamic calibration system has been developed to calibrate TBRs with minimal effort. The system consists of a programmable pump, datalogger, digital balance, and computer. Calibration is performed in two steps: 1) pump calibration and 2) rain gauge calibration. Pump calibration ensures precise control of water flow rates delivered to the rain gauge funnel; rain gauge calibration ensures precise conversion of bucket tip times to actual rainfall rates. Calibration of the pump and one rain gauge for 10 selected pump rates typically requires about 8 h. Data files generated during rain gauge calibration are used to compute rainfall intensities and amounts from a record of bucket tip times collected in the field. The system was tested using 5 types of commercial TBRs (15.2-, 20.3-, and 30.5-cm diameters; 0.1-, 0.2-, and 1.0-mm resolutions) and using 14 TBRs of a single type (20.3-cm diameter; 0.1-mm resolution). Ten pump rates ranging from 3 to 154 mL min-1 were used to calibrate the TBRs and represented rainfall rates between 6 and 254 mm h-1 depending on the rain gauge diameter. All pump calibration results were very linear with R2 values greater than 0.99. All rain gauges exhibited large nonlinear underestimation errors (between 5% and 29%) that decreased with increasing rain gauge resolution and increased with increasing rainfall rate, especially for rates greater than 50 mm h-1. Calibration curves of bucket tip time against the reciprocal of the true pump rate for all rain gauges also were linear with R2 values of 0.99. Calibration data for the 14 rain gauges of the same type were very similar, as indicated by slope values that were within 14% of each other and ranged from about 367 to 417 s mm h-1. The developed system can calibrate TBRs efficiently, accurately, and virtually unattended and could be modified for use with other

Research progress in TIPS shunt dysfunction and recanalization

Directory of Open Access Journals (Sweden)

WANG Tingting

2015-11-01

Full Text Available Transjugular intrahepatic portosystemic shunt (TIPS is widely used in the treatment of cirrhotic portal hypertension and its associated complications. However, postoperative shunt dysfunction has been an important factor restricting the clinical application of TIPS. This article summarizes the use of shunt, the incidence of shunt dysfunction after TIPS, preventive measures and diagnostic methods for shunt dysfunction, and indications and techniques of shunt recanalization, in order to enhance our knowledge of shunt dysfunction and recanalization, which could further improve the efficacy of TIPS for cirrhotic portal hypertension.

Improved method for determining the stress relaxation at the crack tip

Science.gov (United States)

Grinevich, A. V.; Erasov, V. S.; Avtaev, V. V.

2017-10-01

A technique is suggested to determine the stress relaxation at the crack tip during tests of a specimen of a new type at a constant crack opening fixed by a stay bolt. The shape and geometry of the specimen make it possible to set the load and to determine the crack closure force after long-term exposure using the force transducer of a tensile-testing machine. The stress relaxation at the crack tip is determined in a V95pchT2 alloy specimen at elevated temperatures.

Functionalization of Probe Tips and Supports for Single-Molecule Recognition Force Microscopy

Science.gov (United States)

Ebner, Andreas; Wildling, Linda; Zhu, Rong; Rankl, Christian; Haselgrübler, Thomas; Hinterdorfer, Peter; Gruber, Hermann J.

The measuring tip of a force microscope can be converted into a monomolecular sensor if one or few "ligand" molecules are attached to the apex of the tip while maintaining ligand function. Functionalized tips are used to study fine details of receptor-ligand interaction by force spectroscopy or to map cognate "receptor" molecules on the sample surface. The receptor (or target) molecules can be present on the surface of a biological specimen; alternatively, soluble target molecules must be immobilized on ultraflat supports. This review describes the methods of tip functionalization, as well as target molecule immobilization. Silicon nitride tips, silicon chips, and mica have usually been functionalized in three steps: (1) aminofunctionalization, (2) crosslinker attachment, and (3) ligand/receptor coupling, whereby numerous crosslinkers are available to couple widely different ligand molecules. Gold-covered tips and/or supports have usually been coated with a self-assembled monolayer, on top of which the ligand/receptor molecule has been coupled either directly or via a crosslinker molecule. Apart from these general strategies, many simplified methods have been used for tip and/or support functionalization, even single-step methods such as adsorption or chemisorption being very efficient under suitable circumstances. All methods are described with the same explicitness and critical parameters are discussed. In conclusion, this review should help to find suitable methods for specific problems of tip and support functionalization.

Teaching Tip: Adding Intercultural Communication to an IS Curriculum

Science.gov (United States)

Mitchell, Alanah; Benyon, Rob

2018-01-01

Increasingly, today's information systems (IS) programs are focused on making sure students are graduating with well-developed soft skills. One of these necessary soft skills is intercultural communication, which is the ability to communicate with people from different cultures. This teaching tip presents an assignment designed to increase the…

Comparison of classical methods for blade design and the influence of tip correction on rotor performance

DEFF Research Database (Denmark)

Sørensen, Jens Nørkær; Okulov, Valery; Mikkelsen, Robert Flemming

2016-01-01

The classical blade-element/momentum (BE/M) method, which is used together with different types of corrections (e.g. the Prandtl or Glauert tip correction), is today the most basic tool in the design of wind turbine rotors. However, there are other classical techniques based on a combination...

LOTTTTUCE: Layer Oriented Tip-Tilt Turbulence Tomography using Covariance and Elevation

International Nuclear Information System (INIS)

Lai, Olivier; Hayano, Yutaka; Oya, Shin; Chun, Mark; Lu, Jessica R; Toomey, Douglas

2015-01-01

LOTTTTUCE is based upon the fact that turbulence at the pupil produces correlated tip-tilt motion over the entire field (averaging the tip-tilt across the widest field possible gives the strength of the turbulence at the telescope), while the on-axis (any axis) image motion measures the integrated tip-tilt over the line of sight (single stars provide the variance of the tip-tilt, which allows to infer the integrated seeing). Between these two extremes, the amount of correlation across a given field size is the integral of the turbulence from the ground to the altitude where the tip-tilt decorrelates over the meta-pupil. Differentiating the altitude- integrated tip-tilt with respect to altitude generates an estimate of tip-tilt (hence turbulence, assuming Kolmogorov properties) at each altitude. Alternately, the 3D Fourier transform of a data cube containing the time evolution of the tip (or tilt) across the field allows to determine the amount of energy for “field” frequencies (in other words, the integrated seeing across each same size patches) and the temporal spectrum of each of these features. Differentiating the spectrum with respect to spatial frequency would provide the amount of energy, as well as speed and direction, of each layer. The LOTTTTUCE method is a novel method of measuring the vertical turbulence profile that uses wide field tip-tilt information such as that provided by Pan-STARRS. However, the method also has limitations due to tip-tilt decorrelation as a function of meta-pupil overlap, finite outer scale, and non-Kolmogorov power spectrum. (paper)

Kajian Gaya Interior Pada Restoran Tip Top di Kota Medan

OpenAIRE

Kevin

2016-01-01

The purpose of this study was to identify / determine the style of interior design that is applied to the Tip Top Restaurant in Medan as well as the public perception of the interior arrangement of Tip Top Restaurant in Medan by using qualitative and quantitative research methods. Qualitative research methods now that the observation / observation, observation of interior elements Tip Top restaurant is analyzed based on the criteria of interior design, this is done in order to ...

Comparison of different types of phacoemulsification tips. I. Quantitative analysis of elemental composition and tip surface microroughness.

Science.gov (United States)

Tsaousis, Konstantinos T; Werner, Liliana; Perez, Jesus Paulo; Li, He J; Reiter, Nicholas; Guan, Jia J; Mamalis, Nick

2016-09-01

To evaluate the elemental composition of phacoemulsification tips and their surface roughness in the microscale. John A. Moran Eye Center and Utah Nanofab, College of Engineering, University of Utah, Salt Lake City, Utah, USA. Experimental study. Seven types of phacoemulsification tips were studied. The phaco tips were examined through energy-dispersive x-ray spectroscopy (EDS) and x-ray photoelectron spectroscopy (XPS) for elemental composition. In addition, the roughness of the opening in all tips was assessed through 3-dimensional white-light interferometry. Elemental analysis showed considerable differences in the surface layers between manufacturers. Alcon tips had a thinner oxidized titanium (Ti) layer in their surface. Through XPS, vanadium was not detected in the superficial layers of any tip, but only in deeper levels. The microroughness surface analysis showed comparable results regarding their root-mean-square (RMS) metric. Maximum peak valley distance values varied and appeared to be dependent on the quality of material process rather than the material itself. Phacoemulsification tips are made of Ti alloys and showed differences between models, especially regarding their composition in the superficial layers. Their opening end roughness showed an overall appropriate RMS value of less than 1.0 μm in all cases. The existence of small defected areas highlights the importance of adequate quality control of these critical surgical instruments. None of the authors has a financial or proprietary interest in any material or method mentioned. Copyright © 2016 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Dual-tip magnetic force microscopy with suppressed influence on magnetically soft samples

International Nuclear Information System (INIS)

Precner, Marián; Fedor, Ján; Šoltýs, Ján; Cambel, Vladimír

2015-01-01

Standard magnetic force microscopy (MFM) is considered as a powerful tool used for magnetic field imaging at nanoscale. The method consists of two passes realized by the magnetic tip. Within the first one, the topography pass, the magnetic tip directly touches the magnetic sample. Such contact perturbs the magnetization of the sample explored. To avoid the sample touching the magnetic tip, we present a new approach to magnetic field scanning by segregating the topological and magnetic scans with two different tips located on a cut cantilever. The approach minimizes the disturbance of sample magnetization, which could be a major problem in conventional MFM images of soft magnetic samples. By cutting the cantilever in half using the focused ion beam technique, we create one sensor with two different tips—one tip is magnetized, and the other one is left non-magnetized. The non-magnetized tip is used for topography and the magnetized one for the magnetic field imaging. The method developed we call dual-tip magnetic force microscopy (DT-MFM). We describe in detail the dual-tip fabrication process. In the experiments, we show that the DT-MFM method reduces significantly the perturbations of the magnetic tip as compared to the standard MFM method. The present technique can be used to investigate microscopic magnetic domain structures in a variety of magnetic samples and is relevant in a wide range of applications, e.g., data storage and biomedicine. (paper)

Rhinoplasty: a simplified, three-stitch, open tip suture technique. Part I: primary rhinoplasty.

Science.gov (United States)

Daniel, R K

1999-04-01

Tip suture techniques offer a reliable and dramatic method of tip modification without needing to interrupt the alar rim strip or add tip grafts. The present simplified three-stitch technique consists of the following: (1) a strut suture to fix the columella strut between the crura, (2) bilateral domal creation sutures to create tip definition, and (3) a domal equalization suture to narrow and align the domes. If required, columella septal sutures can be added; either a dorsal rotational suture or a transfixion projection suture can be used. This simplified method represents a refinement based on more than 13 years of experience with tip suture techniques. It does not require a complex operative sequence or specialized sutures. Primary indications are moderate tip deformities of inadequate definition and excessive width and certain specific tip deformities, including the parenthesis tip and nostril/tip disproportion. The primary contraindications are for patients with minor tip deformities that are best done through a closed approach and those with severe tip deformities requiring an open structure graft. The technique is simple, efficacious, and easily learned.

Short communication: QTL mapping for ear tip-barrenness in maize

Energy Technology Data Exchange (ETDEWEB)

Ding, J.; Ma, J.; Chen, J.; Ai, T.; Li, Z.; Tian, Z.; Wu, S.; Chen, W.; Wu, J.

2016-11-01

Barren tip on corn ear is an important agronomic trait in maize, which is highly associated with grain yield. Understanding the genetic basis of tip-barrenness may help to reduce the ear tip-barrenness in breeding programs. In this study, ear tip-barrenness was evaluated in two environments in a F2:3 population, and it showed significant genotypic variation for ear tip-barrenness in both environments. Using mixed-model composite interval mapping method, three additive effects quantitative trait loci (QTL) for ear tip-barrenness were mapped on chromosomes 2, 3 and 6, respectively. They explained 16.6% of the phenotypic variation, and no significant QTL × Environment interactions and digenic interactions were detected. The results indicated that additive effect was the main genetic basis for ear tip-barrenness in maize. This is the first report of QTL mapped for ear tip-barrenness in maize. (Author)

Use of embryogenic cell suspension and meristem-tip cultures for mutation breeding of apomictic Musa species

International Nuclear Information System (INIS)

Novak, F.J.; Afza, R.; Duren, M. van

1990-01-01

Full text: Breeding by crossing is difficult for banana and plantain. The plants are heterozygous, therefore mutagenic treatment may uncover a recessive allele by mutating or deleting a corresponding dominant allele. Meristem tips were excised from in vitro growing shoots and used for mutation experiments. Induction was carried out by irradiating shoot tips with γ rays and/or by treatment of explants with ethylmethanesulfonate (EMS). Cell suspension was initiated from corm and leaf tissue excised from in vitro grown plantlets. Mutagenised cell suspensions were derived from leaf and corm tissues irradiated with 60 Co γ rays - (10 to 60 Gy, 8 Gy/min). Musa clones exhibited differences in radiosensitivity and post-irradiation recovery. Doses of 20 to 40 Gy seem suitable for mutation induction. The EMS concentration of 25 mM for 4 hours was found effective for isolated shoot tips. Considerable phenotypic variation was observed among plants regenerated from in vitro shoot tips after mutagenic treatment. Leaf and corm explants kept their morphogenic ability in embryogenic cell suspensions after irradiation up to 25 Gy. (author)

Tipping Point

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Full Text Available ... death electrical fall furniture head injury product safety television tipover tv Watch the video in Adobe Flash ... tv tip-overs. The force of a large television falling from tipping furniture can be staggering. A ...

Tipping Point

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Full Text Available ... and furniture, appliance and tv tip-overs. The force of a large television falling from tipping furniture ... 50 lb. TV falls with about the same force as child falling from the third story of ...

Tipping Point

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Full Text Available ... Tipping Point by CPSC Blogger September 22, 2009 appliance child Childproofing CPSC danger death electrical fall furniture ... about horrible accidents involving young children and furniture, appliance and tv tip-overs. The force of a ...

Tips for TIPS

NARCIS (Netherlands)

Cuijpers, C.F.

2015-01-01

The transjugular intrahepatic portosystemic shunt (TIPS) procedure is one of the most technically challenging procedures in interventional radiology. During the procedure, interventional radiologists (IRs) insert very thin and long instruments through a little incision in the patient’s neck. They

Novel synthetic lethality screening method identifies TIP60-dependent radiation sensitivity in the absence of BAF180.

Science.gov (United States)

Hopkins, Suzanna R; McGregor, Grant A; Murray, Johanne M; Downs, Jessica A; Savic, Velibor

2016-10-01

In recent years, research into synthetic lethality and how it can be exploited in cancer treatments has emerged as major focus in cancer research. However, the lack of a simple to use, sensitive and standardised assay to test for synthetic interactions has been slowing the efforts. Here we present a novel approach to synthetic lethality screening based on co-culturing two syngeneic cell lines containing individual fluorescent tags. By associating shRNAs for a target gene or control to individual fluorescence labels, we can easily follow individual cell fates upon siRNA treatment and high content imaging. We have demonstrated that the system can recapitulate the functional defects of the target gene depletion and is capable of discovering novel synthetic interactors and phenotypes. In a trial screen, we show that TIP60 exhibits synthetic lethality interaction with BAF180, and that in the absence of TIP60, there is an increase micronuclei dependent on the level of BAF180 loss, significantly above levels seen with BAF180 present. Moreover, the severity of the interactions correlates with proxy measurements of BAF180 knockdown efficacy, which may expand its usefulness to addressing synthetic interactions through titratable hypomorphic gene expression. Copyright © 2016. Published by Elsevier B.V.

CPAP Tips

Science.gov (United States)

... now Try it free Find out why Close CPAP Tips from FDA USFoodandDrugAdmin Loading... Unsubscribe from USFoodandDrugAdmin? ... apnea and use a continuous positive airway pressure (CPAP) device when sleeping? Here are some tips from ...

KNOW-BLADE task-3.2 report: Tip shape study

DEFF Research Database (Denmark)

Sørensen, Niels N.; Johansen, Jeppe; Conway, S.

2005-01-01

For modern rotor blades with their very large aspect ratio, the blade tip is a very limited part of the overall rotor, and as such of limited importance for the overall aerodynamics of the rotor. Even though they may not be very important for the overallpower production, the tip noise can be very...... important for the acoustics of the rotor [15], and the blade tips can as well be important for the aerodynamic damping properties of the rotor blades [13]. Unfortunately, not many options exists for predictingthe aerodynamic behavior of blade tips using computational methods. Experimentally it is di...

Tipping Point

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Full Text Available ... OnSafety CPSC Stands for Safety The Tipping Point Home > 60 Seconds of Safety (Videos) > The Tipping Point ... 24 hours a day. For young children whose home is a playground, it’s the best way to ...

THE ROLE OF TIPPING IN REDUCING LABOUR COSTS: CASE OF SECTOR RETAIL PETROLEUM PRODUCTS

Directory of Open Access Journals (Sweden)

Andrej Raspor

2014-05-01

Full Text Available The purpose of this paper was to determine whether tipping could reduce labour costs in the petroleum products retail sector. The research we present was designed on the basis of survey results gathered from Slovenian petrol stations in 2009 and 2010. We have identified the following factors in the tipping process: job satisfaction, flexibility, service quality, satisfaction, motivation and the factor of receiving tips. The analysis showed correlation between methods used to increase the value of tips and better service quality, increased financial and numerical flexibility, motivation, satisfaction upon receipt of tips and the method used to increase the value of tips. In order to decrease labour costs we propose that the management take control of tipping and integrates tips into the reward system. Also, the employees should be made aware about how tipping improves service and increases their income.

CPAP Tips

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Full Text Available ... now Try it free Find out why Close CPAP Tips from FDA USFoodandDrugAdmin Loading... Unsubscribe from USFoodandDrugAdmin? ... apnea and use a continuous positive airway pressure (CPAP) device when sleeping? Here are some tips from ...

Tips to Prevent Mosquito Bites

Science.gov (United States)

... discourage mosquitoes, ticks and other biting insects from landing on you. Here are tips for other preventive ... CDC Mosquito Control Methods - NPIC Exit Top of Page Contact Us to ask a question, provide feedback, ...

Leading tip drives soma translocation via forward F-actin flow during neuronal migration.

Science.gov (United States)

He, Min; Zhang, Zheng-hong; Guan, Chen-bing; Xia, Di; Yuan, Xiao-bing

2010-08-11

Neuronal migration involves coordinated extension of the leading process and translocation of the soma, but the relative contribution of different subcellular regions, including the leading process and cell rear, in driving soma translocation remains unclear. By local manipulation of cytoskeletal components in restricted regions of cultured neurons, we examined the molecular machinery underlying the generation of traction force for soma translocation during neuronal migration. In actively migrating cerebellar granule cells in culture, a growth cone (GC)-like structure at the leading tip exhibits high dynamics, and severing the tip or disrupting its dynamics suppressed soma translocation within minutes. Soma translocation was also suppressed by local disruption of F-actin along the leading process but not at the soma, whereas disrupting microtubules along the leading process or at the soma accelerated soma translocation. Fluorescent speckle microscopy using GFP-alpha-actinin showed that a forward F-actin flow along the leading process correlated with and was required for soma translocation, and such F-actin flow depended on myosin II activity. In migrating neurons, myosin II activity was high at the leading tip but low at the soma, and increasing or decreasing this front-to-rear difference accelerated or impeded soma advance. Thus, the tip of the leading process actively pulls the soma forward during neuronal migration through a myosin II-dependent forward F-actin flow along the leading process.

Efficient regeneration of sorghum, Sorghum bicolor (L.) Moench, from shoot-tip explant.

Science.gov (United States)

Syamala, D; Devi, Prathibha

2003-12-01

Novel protocols for production of multiple shoot-tip clumps and somatic embryos of Sorghum bicolor (L.) Moench were developed with long-term goal of crop improvement through genetic transformation. Multiple shoot-tip clumps were developed in vitro from shoot-tip explant of one-week old seedling, cultured on MS medium containing only BA (0.5, 1 or 2 mg/l) or both BA (1 or 2 mg/l) and 2,4-D (0.5 mg/l) with bi-weekly subculture. Somatic embryos were directly produced on the enlarged dome shaped growing structures that developed from the shoot-tips of one-week old seedling explants (without any callus formation) when cultured on MS medium supplemented with both 2,4-D (0.5 mg/l) and BA (0.5 mg/l). However, the supplementation of MS medium with only 2,4-D (0.5 mg/l) induced compact callus without any plantlet regeneration. Each multiple shoot-clump was capable of regenerating more than 80 shoots via an intensive differentiation of both axillary and adventitious shoot buds, the somatic embryos were capable of 90% germination, plant conversion and regeneration. The regenerated shoots could be efficiently rooted on MS medium containing indole-3-butyric acid (IBA 1 mg/l). The plants were successfully transplanted to glasshouse and grown to maturity with a survival rate of 98%. Morphogenetic response of the explants was found to be genotypically independent.

Tipping Point

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KNOW-BLADE, task-3.2 report, tip shape study

Energy Technology Data Exchange (ETDEWEB)

Soerensen, N.N.; Johansen, J.; Conway, S.; Voutsinas, S.; Hansen, M.O.L.; Stuermer, A.

2005-01-01

For modern rotor blades with their very large aspect ratio, the blade tip is a very limited part of the overall rotor, and as such of limited importance for the overall aerodynamics of the rotor. Even though they may not be very important for the overall power production, the tip noise can be very important for the acoustics of the rotor [15], and the blade tips can as well be important for the aerodynamic damping properties of the rotor blades [13]. Unfortunately, not many options exists for predicting the aerodynamic behavior of blade tips using computational methods. Experimentally it is dicult to perform detailed measurements in the form of pressure and velocity measurements in natural wind conditions on modern large scale turbines due to the inherent unsteadiness in the natural wind. The present study describes the application of four different Navier-Stokes solvers to tip shape studies, and shows that these codes are well suited to study the flow around different tip shape geometries, and can predict the pressure distributions at the blade tip quite accurately. (au)

In vitro propagation of peanut (Arachis hypogaea L.) by shoot tip culture.

Science.gov (United States)

Ozudogru, Elif Aylin; Kaya, Ergun; Lambardi, Maurizio

2013-01-01

Peanut (Arachis hypogaea L.), also known as groundnut, is the most important species of Arachis genus, originating from Brazil and Peru. Peanut seeds contain high seed oil, proteins, amino acids, and vitamin E, and are consumed worldwide as edible nut, peanut butter, or candy, and peanut oil extracted from the seeds. The meal remaining after oil extraction is also used for animal feed. However, its narrow germplasm base, together with susceptibility to diseases, pathogens, and weeds, decreases yield and seed quality and causes great economic losses annually. Hence, the optimization of efficient in vitro propagation procedures would be highly effective for peanut propagation, as it would raise yield and improve seed quality and flavor. Earlier reports on traditional micropropagation methods, based on axillary bud proliferation which guarantees the multiplication of true-to-type plants, are still limited. This chapter describes a micropropagation protocol to improve multiple shoot formation from shoot-tip explants by using AgNO(3) in combination with plant growth regulators.

Plant Cell Culture Initiation: practical tips

NARCIS (Netherlands)

Hall, R.D.

2001-01-01

The use of cultured plant cells in either organized or unorganized form has increased vey considerably in the last 10-15 yr. Many new technologies have been developed and applications in both fundamental and applied research have led to the development of some powerful tools for improving our

Neural network approximation of tip-abrasion effects in AFM imaging

International Nuclear Information System (INIS)

Bakucz, Peter; Dziomba, Thorsten; Koenders, Ludger; Krüger-Sehm, Rolf; Yacoot, Andrew

2008-01-01

The abrasion (wear) of tips used in scanning force microscopy (SFM) directly influences SFM image quality and is therefore of great relevance to quantitative SFM measurements. The increasing implementation of automated SFM measurement schemes has become a strong driving force for increasing efforts towards the prediction of tip wear, as it needs to be ensured that the probe is exchanged before a level of tip wear is reached that adversely affects the measurement quality. In this paper, we describe the identification of tip abrasion in a system of SFM measurements. We attempt to model the tip-abrasion process as a concatenation of a mapping from the measured AFM data to a regression vector and a nonlinear mapping from the regressor space to the output space. The mapping is formed as a basis function expansion. Feedforward neural networks are used to approximate this mapping. The one-hidden layer network gave a good quality of fit for the training and test sets for the tip-abrasion system. We illustrate our method with AFM measurements of both fine periodic structures and randomly oriented sharp features and compare our neural network results with those obtained using other methods

Neural network approximation of tip-abrasion effects in AFM imaging

Science.gov (United States)

Bakucz, Peter; Yacoot, Andrew; Dziomba, Thorsten; Koenders, Ludger; Krüger-Sehm, Rolf

2008-06-01

The abrasion (wear) of tips used in scanning force microscopy (SFM) directly influences SFM image quality and is therefore of great relevance to quantitative SFM measurements. The increasing implementation of automated SFM measurement schemes has become a strong driving force for increasing efforts towards the prediction of tip wear, as it needs to be ensured that the probe is exchanged before a level of tip wear is reached that adversely affects the measurement quality. In this paper, we describe the identification of tip abrasion in a system of SFM measurements. We attempt to model the tip-abrasion process as a concatenation of a mapping from the measured AFM data to a regression vector and a nonlinear mapping from the regressor space to the output space. The mapping is formed as a basis function expansion. Feedforward neural networks are used to approximate this mapping. The one-hidden layer network gave a good quality of fit for the training and test sets for the tip-abrasion system. We illustrate our method with AFM measurements of both fine periodic structures and randomly oriented sharp features and compare our neural network results with those obtained using other methods.

The tipping point: A mathematical model for the profit-driven abandonment of restaurant tipping

Science.gov (United States)

Clifton, Sara M.; Herbers, Eileen; Chen, Jack; Abrams, Daniel M.

2018-02-01

The custom of voluntarily tipping for services rendered has gone in and out of fashion in America since its introduction in the 19th century. Restaurant owners that ban tipping in their establishments often claim that social justice drives their decisions, but we show that rational profit-maximization may also justify the decisions. Here, we propose a conceptual model of restaurant competition for staff and customers, and we show that there exists a critical conventional tip rate at which restaurant owners should eliminate tipping to maximize profits. Because the conventional tip rate has been increasing steadily for the last several decades, our model suggests that restaurant owners may abandon tipping en masse when that critical tip rate is reached.

Variable-temperature independently driven four-tip scanning tunneling microscope

International Nuclear Information System (INIS)

Hobara, Rei; Nagamura, Naoka; Hasegawa, Shuji; Matsuda, Iwao; Yamamoto, Yuko; Miyatake, Yutaka; Nagamura, Toshihiko

2007-01-01

The authors have developed an ultrahigh vacuum (UHV) variable-temperature four-tip scanning tunneling microscope (STM), operating from room temperature down to 7 K, combined with a scanning electron microscope (SEM). Four STM tips are mechanically and electrically independent and capable of positioning in arbitrary configurations in nanometer precision. An integrated controller system for both of the multitip STM and SEM with a single computer has also been developed, which enables the four tips to operate either for STM imaging independently and for four-point probe (4PP) conductivity measurements cooperatively. Atomic-resolution STM images of graphite were obtained simultaneously by the four tips. Conductivity measurements by 4PP method were also performed at various temperatures with the four tips in square arrangement with direct contact to the sample surface

High precision attachment of silver nanoparticles on AFM tips by dielectrophoresis.

Science.gov (United States)

Leiterer, Christian; Wünsche, Erik; Singh, Prabha; Albert, Jens; Köhler, Johann M; Deckert, Volker; Fritzsche, Wolfgang

2016-05-01

AFM tips are modified with silver nanoparticles using an AC electrical field. The used technique works with sub-micron precision and also does not require chemical modification of the tip. Based on the electrical parameters applied in the process, particle density and particle position on the apex of the tip can be adjusted. The feasibility of the method is proven by subsequent tip-enhanced Raman spectroscopy (TERS) measurements using the fabricated tips as a measurement probe. Since this modification process itself does not require any lithographic processing, the technique can be easily adapted to modify AFM tips with a variety of nanostructures with pre-defined properties, while being parallelizable for a potential commercial application.

Tip-modified Propellers

DEFF Research Database (Denmark)

Andersen, Poul

1999-01-01

The paper deals with tip-modified propellers and the methods which, over a period of two decades, have been applied to develop such propellers. The development is driven by the urge to increase the efficiency of propellers and can be seen as analogous to fitting end plates and winglets to aircraft...... propeller, have efficiency increases of a reasonable magnitude in both open-water and behind-ship conditions....

Adjusting the displaced tip of peripherally inserted central catheter under DSA guidance

International Nuclear Information System (INIS)

Mao Yanjun; Dong Huijuan; Zhang Lingjuan; Li Hongmei; Xu Lianqin

2009-01-01

Objective: To explore a new method to adjust the displaced tip of peripherally inserted central catheter (PICC) under DSA guidance. Methods: Under DSA guidance, the displaced tip of PICC was repositioned to the ideal junction area of superior vena cava with right atrium with proper manipulation. Results: Under DSA guidance, the displaced tip of PICC was successfully corrected in 13 cases. The mean operative time was 15.53 minutes, which was markedly shorter than that needed by blind adjusting beside the bed. Conclusion: The displacement of PICC tip is a common occurrence, which is hard to be avoided. Under DSA guidance, the adjusting manipulation of the displaced PICC tip is safe and time-saving with high successful rate. It is worth popularizing this technique in clinical practice. (authors)

On the development of a magnetoresistive sensor for blade tip timing and blade tip clearance measurement systems

Science.gov (United States)

Tomassini, R.; Rossi, G.; Brouckaert, J.-F.

2016-10-01

A simultaneous blade tip timing (BTT) and blade tip clearance (BTC) measurement system enables the determination of turbomachinery blade vibrations and ensures the monitoring of the existing running gaps between the blade tip and the casing. This contactless instrumentation presents several advantages compared to the well-known telemetry system with strain gauges, at the cost of a more complex data processing procedure. The probes used can be optical, capacitive, eddy current as well as microwaves, everyone with its dedicated electronics and many existing different signal processing algorithms. Every company working in this field has developed its own processing method and sensor technology. Hence, repeating the same test with different instrumentations, the answer is often different. Moreover, rarely it is possible to achieve reliability for in-service measurements. Developments are focused on innovative instrumentations and a common standard. This paper focuses on the results achieved using a novel magnetoresistive sensor for simultaneous tip timing and tip clearance measurements. The sensor measurement principle is described. The sensitivity to gap variation is investigated. In terms of measurement of vibrations, experimental investigations were performed at the Air Force Institute of Technology (ITWL, Warsaw, Poland) in a real aeroengine and in the von Karman Institute (VKI) R2 compressor rig. The advantages and limitations of the magnetoresistive probe for turbomachinery testing are highlighted.

New Technique for Fabrication of Scanning Single-Electron Transistor Microscopy Tips

Science.gov (United States)

Goodwin, Eric; Tessmer, Stuart

Fabrication of glass tips for Scanning Single-Electron Transistor Microscopy (SSETM) can be expensive, time consuming, and inconsistent. Various techniques have been tried, with varying levels of success in regards to cost and reproducibility. The main requirement for SSETM tips is to have a sharp tip ending in a micron-scale flat face to allow for deposition of a quantum dot. Drawing inspiration from methods used to create tips from optical fibers for Near-Field Scanning Optical Microscopes, our group has come up with a quick and cost effective process for creating SSETM tips. By utilizing hydrofluoric acid to etch the tips and oleic acid to guide the etch profile, optical fiber tips with appropriate shaping can be rapidly prepared. Once etched, electric leads are thermally evaporated onto each side of the tip, while an aluminum quantum dot is evaporated onto the face. Preliminary results using various metals, oxide layers, and lead thicknesses have proven promising.

Mentoring and Coaching Tips: How Educators Can Help Each Other

Science.gov (United States)

Waterman, Sheryn Spencer

2013-01-01

This book is for educators at all levels and is packed with creative, use-now tips and activities to support new and struggling teachers. Combining real-life scenarios with current research, the author demonstrates how educators can get the most out of available resources, promote a school culture devoted to helping and caring, and meet common…

Twelve tips for applying change models to curriculum design, development and delivery.

Science.gov (United States)

McKimm, Judy; Jones, Paul Kneath

2017-10-25

Drawing primarily from business and management literature and the authors' experience, these 12 tips provide guidance to organizations, teams, and individuals involved in curriculum or program development at undergraduate, postgraduate, and continuing education levels. The tips are based around change models and approaches and can help underpin successful curriculum review, development, and delivery, as well as fostering appropriate educational innovation. A range of tools exist to support systematic program development and review, but even relatively simple changes need to take account of many factors, including the complexity of the environment, stakeholder engagement, cultural and psychological aspects, and the importance of followers.

The TIPS Liquidity Premium

DEFF Research Database (Denmark)

Andreasen, Martin Møller; Christensen, Jens H.E.; Simon Riddell, Simon

We introduce an arbitrage-free term structure model of nominal and real yields that accounts for liquidity risk in Treasury inflation-protected securities (TIPS). The novel feature of our model is to identify liquidity risk from individual TIPS prices by accounting for the tendency that TIPS, lik...

Vortex methods to answer the need for improved understanding and modelling of tip-loss factors

DEFF Research Database (Denmark)

Branlard, Emmanuel; Dixon, Kristian; Gaunaa, Mac

2013-01-01

Standard blade element momentum (BEM) codes use Prandtl¿s tip-loss correction which relies on simplified vortex theory under the assumption of optimal operating condition and no wake expansion. The various tip-loss functions found in the literature are listed. A simple comparison between them shows...

Sugarcane in vitro culture technology: Opportunities for Kenya's ...

African Journals Online (AJOL)

free clonal materials. Successful protocols for shoot tip culture, callus culture, embryo culture, virus free plant production and somatic embryogenesis have already been established. Thus, in vitro technology can be used to enhance ...

Diversity of endophytic bacteria of Dendrobium officinale based on culture-dependent and culture-independent methods

Directory of Open Access Journals (Sweden)

Cong Pei

2017-01-01

Full Text Available Culture-dependent and culture-independent methods were compared and evaluated in the study of the endophytic diversity of Dendrobium officinale. Culture-independent methods consisted of polymerase chain reaction–denaturing gradient gel electrophoresis (PCR-DGGE and metagenome methods. According to the results, differences were found between the three methods. Three phyla, namely Firmicutes, Proteobacteria, and Actinobacteria, were detected using the culture-dependent method, and two phyla, Firmicutes and Proteobacteria, were detected by the DGGE method. Using the metagenome method, four major phyla were determined, including Proteobacteria (76.54%, Actinobacteria (18.56%, Firmicutes (2.27%, and Bacteroidetes (1.56%. A distinct trend was obtained at the genus level in terms of the method and the corresponding number of genera determined. There were 449 genera and 16 genera obtained from the metagenome and DGGE methods, respectively, and only 7 genera were obtained through the culture-dependent method. By comparison, all the genera from the culture-dependent and DGGE methods were contained in the members determined using the metagenome method. Overall, culture-dependent methods are limited to ‘finding’ endophytic bacteria in plants. DGGE is an alternative to investigating primary diversity patterns; however, the metagenome method is still the best choice for determining the endophytic profile in plants. It is essential to use multiphasic approaches to study cultured and uncultured microbes.

Sharp tipped plastic hollow microneedle array by microinjection moulding

Science.gov (United States)

Yung, K. L.; Xu, Yan; Kang, Chunlei; Liu, H.; Tam, K. F.; Ko, S. M.; Kwan, F. Y.; Lee, Thomas M. H.

2012-01-01

A method of producing sharp tipped plastic hollow microneedle arrays using microinjection moulding is presented in this paper. Unlike traditional approaches, three mould inserts were used to create the sharp tips of the microneedles. Mould inserts with low surface roughness were fabricated using a picosecond laser machine. Sharp tipped plastic hollow microneedles 500 µm in height were fabricated using a microinjection moulding machine developed by the authors’ group. In addition, the strength of the microneedle was studied by simulation and penetration experiments. Results show that the microneedles can penetrate into skin, delivering liquid successfully without any breakage or severe deformation. Techniques presented in this paper can be used to fabricate sharp tipped plastic hollow microneedle arrays massively with low cost.

Sharp tipped plastic hollow microneedle array by microinjection moulding

International Nuclear Information System (INIS)

Yung, K L; Xu, Yan; Kang, Chunlei; Liu, H; Tam, K F; Ko, S M; Kwan, F Y; Lee, Thomas M H

2012-01-01

A method of producing sharp tipped plastic hollow microneedle arrays using microinjection moulding is presented in this paper. Unlike traditional approaches, three mould inserts were used to create the sharp tips of the microneedles. Mould inserts with low surface roughness were fabricated using a picosecond laser machine. Sharp tipped plastic hollow microneedles 500 µm in height were fabricated using a microinjection moulding machine developed by the authors’ group. In addition, the strength of the microneedle was studied by simulation and penetration experiments. Results show that the microneedles can penetrate into skin, delivering liquid successfully without any breakage or severe deformation. Techniques presented in this paper can be used to fabricate sharp tipped plastic hollow microneedle arrays massively with low cost. (paper)

Standard test method for crack-tip opening displacement (CTOD) fracture toughness measurement

CERN Document Server

American Society for Testing and Materials. Philadelphia

2008-01-01

1.1 This test method covers the determination of critical crack-tip opening displacement (CTOD) values at one or more of several crack extension events, and may be used to measure cleavage crack initiation toughness for materials that exhibit a change from ductile to brittle behavior with decreasing temperature, such as ferritic steels. This test method applies specifically to notched specimens sharpened by fatigue cracking. The recommended specimens are three-point bend [SE(B)], compact [C(T)], or arc-shaped bend [A(B)] specimens. The loading rate is slow and influences of environment (other than temperature) are not covered. The specimens are tested under crosshead or clip gage displacement controlled loading. 1.1.1 The recommended specimen thickness, B, for the SE(B) and C(T) specimens is that of the material in thicknesses intended for an application. For the A(B) specimen, the recommended depth, W, is the wall thickness of the tube or pipe from which the specimen is obtained. Superficial surface machini...

Bacterial cell culture

OpenAIRE

sprotocols

2014-01-01

### Materials 1. Glass culture tubes with metal caps and labels - Growth medium, from media room or customized - Glass pipette tubes - Parafilm ### Equipment 1. Vortexer - Fireboy or Bunsen burner - Motorized pipette - Micropipettes and sterile tips ### Procedure For a typical liquid culture, use 5 ml of appropriate medium. The amount in each tube does not have to be exact if you are just trying to culture cells for their precious DNA. 1. Streak an a...

Control of lethal browning by using ascorbic acid on shoot tip ...

African Journals Online (AJOL)

The use of ascorbic acid during explants preparation and the effect of different concentrations of ascorbic acid in controlling lethal browning and survival of the explants in local banana cv. Mzuzu banana were investigated. The explants were taken from young suckers. The shoot tips were cultured on Murashige and Skoog's ...

Robust procedure for creating and characterizing the atomic structure of scanning tunneling microscope tips.

Science.gov (United States)

Tewari, Sumit; Bastiaans, Koen M; Allan, Milan P; van Ruitenbeek, Jan M

2017-01-01

Scanning tunneling microscopes (STM) are used extensively for studying and manipulating matter at the atomic scale. In spite of the critical role of the STM tip, procedures for controlling the atomic-scale shape of STM tips have not been rigorously justified. Here, we present a method for preparing tips in situ while ensuring the crystalline structure and a reproducibly prepared tip structure up to the second atomic layer. We demonstrate a controlled evolution of such tips starting from undefined tip shapes.

Tip-Based Nanofabrication for Scalable Manufacturing

Directory of Open Access Journals (Sweden)

Huan Hu

2017-03-01

Full Text Available Tip-based nanofabrication (TBN is a family of emerging nanofabrication techniques that use a nanometer scale tip to fabricate nanostructures. In this review, we first introduce the history of the TBN and the technology development. We then briefly review various TBN techniques that use different physical or chemical mechanisms to fabricate features and discuss some of the state-of-the-art techniques. Subsequently, we focus on those TBN methods that have demonstrated potential to scale up the manufacturing throughput. Finally, we discuss several research directions that are essential for making TBN a scalable nano-manufacturing technology.

Tip-Based Nanofabrication for Scalable Manufacturing

International Nuclear Information System (INIS)

Hu, Huan; Somnath, Suhas

2017-01-01

Tip-based nanofabrication (TBN) is a family of emerging nanofabrication techniques that use a nanometer scale tip to fabricate nanostructures. Here in this review, we first introduce the history of the TBN and the technology development. We then briefly review various TBN techniques that use different physical or chemical mechanisms to fabricate features and discuss some of the state-of-the-art techniques. Subsequently, we focus on those TBN methods that have demonstrated potential to scale up the manufacturing throughput. Finally, we discuss several research directions that are essential for making TBN a scalable nano-manufacturing technology.

Tissue culture of black pepper (piper nigrum l.) in Pakistan

International Nuclear Information System (INIS)

Hussain, A.; Naz, S.; Nazir, H.; Shinwari, Z.K.

2011-01-01

Black pepper (Piper nigrum L.) the 'King of Spices' is a universal table condiment. It is extensively used in Pakistani cuisines and herbal medicines and imported in bulk from neighboring countries. The black pepper vine is generally cultivated by seed because other vegetative propagation methods are slow and time consuming. Therefore the tissue culture technique is considered more efficient and reliable method for rapid and mass propagation of this economically important plant. The present study was initiated to develop protocol for micro-propagation of black pepper vine. The stem, leaf and shoot tip explants from mature vine were cultured on MS medium supplemented with different concentrations of plant growth regulators (2,4-D, BA, IBA). Best callus was produced on MS medium with 1.5 mg/l BA by shoot tip explant. Shoot regeneration was excellent on MS medium with 0.5 mg/l BA. The plantlets formed were rooted best on 1.5 mg/l IBA. The rooted plants were transplanted in soil medium and acclimatized in growth room. The plants raised were test planted under the local conditions of Hattar. (author)

Management of Bleeding Duodenal Varices with Combined TIPS Decompression and Trans-TIPS Transvenous Obliteration Utilizing 3% Sodium Tetradecyl Sulfate Foam Sclerosis

Directory of Open Access Journals (Sweden)

Wael E Saad

2014-01-01

Full Text Available Objectives: Endoscopic experience in the management of duodenal varices (DVs is limited and challenging given the anatomic constraints and limited experience. The endovascular management of DVs is not yet established and the controversy of whether to manage them by decompression with a transjugular intrahepatic portosystemic shunt (TIPS or by transvenous obliteration is unresolved. In the literature, the 6-12 month rebleeding rate of DVs after TIPS is 21-37% and after transvenous obliteration is 13%. The purpose of the study is to evaluate the clinical outcome of combined TIPS decompression and transvenous obliteration/sclerosis. Materials and Methods: This is a retrospective study (case series of two institutions, evaluating patients who underwent TIPS and/or transvenous obliteration/sclerosis for bleeding DVs (from January 2009 to June 2013. TIPS was performed according to a standard procedure using covered stents. Transvenous obliteration (variceal sclerosis from the systemic and/or portal venous circulation was performed utilizing 3% sodium tetradecyl sulfate foam. Transvenous obliteration was commonly augmented with coils and/or vascular plugs. Technical (technical success of establishing TIPS and completely obliterating the DVs and clinical outcomes (rebleeding rate and survival were evaluated. Results: Five patients with liver cirrhosis presenting with bleeding DVs were included in the study with all eventually (and coincidentally receiving TIPS and transvenous obliteration. Two of the five patients underwent concomitant TIPS and transvenous obliteration in the same procedural setting. However, three patients underwent transvenous obliteration due to bleeding despite a patent TIPS that had been previously placed. The average time from TIPS placement to transvenous obliteration was 125 days (range: 3-324 days. After having both procedures, there was no rebleeding in the patients during a mean follow-up period of 22 months (6-50 months

z calibration of the atomic force microscope by means of a pyramidal tip

DEFF Research Database (Denmark)

Jensen, Flemming

1993-01-01

A new method for imaging the probe tip of an atomic force microscope cantilever by the atomic force microscope itself (self-imaging) is presented. The self-imaging is accomplished by scanning the probe tip across a sharper tip on the surface. By using a pyramidal probe tip with a very well......-defined aspect ratio, this technique provides an excellent z-calibration standard for the atomic force microscope....

AERODYNAMICS OF WING TIP SAILS

Directory of Open Access Journals (Sweden)

MUSHTAK AL-ATABI

2006-06-01

Full Text Available Observers have always been fascinated by soaring birds. An interesting feature of these birds is the existence of few feathers extending from the tip of the wing. In this paper, small lifting surfaces were fitted to the tip of a NACA0012 wing in a fashion similar to that of wing tip feathers. Experimental measurements of induced drag, longitudinal static stability and trailing vortex structure were obtained.The tests showed that adding wing tip surfaces (sails decreased the induced drag factor and increased the longitudinal static stability. Results identified two discrete appositely rotated tip vortices and showed the ability of wing tip surfaces to break them down and to diffuse them.

Preparation of scanning tunneling microscopy tips using pulsed alternating current etching

International Nuclear Information System (INIS)

Valencia, Victor A.; Thaker, Avesh A.; Derouin, Jonathan; Valencia, Damian N.; Farber, Rachael G.; Gebel, Dana A.; Killelea, Daniel R.

2015-01-01

An electrochemical method using pulsed alternating current etching (PACE) to produce atomically sharp scanning tunneling microscopy (STM) tips is presented. An Arduino Uno microcontroller was used to control the number and duration of the alternating current (AC) pulses, allowing for ready optimization of the procedures for both Pt:Ir and W tips using a single apparatus. W tips prepared using constant and pulsed AC power were compared. Tips fashioned using PACE were sharper than those etched with continuous AC power alone. Pt:Ir tips were prepared with an initial coarse etching stage using continuous AC power followed by fine etching using PACE. The number and potential of the finishing AC pulses was varied and scanning electron microscope imaging was used to compare the results. Finally, tip quality using the optimized procedures was verified by UHV-STM imaging. With PACE, at least 70% of the W tips and 80% of the Pt:Ir tips were of sufficiently high quality to obtain atomically resolved images of HOPG or Ni(111)

Preparation of scanning tunneling microscopy tips using pulsed alternating current etching

Energy Technology Data Exchange (ETDEWEB)

Valencia, Victor A.; Thaker, Avesh A.; Derouin, Jonathan; Valencia, Damian N.; Farber, Rachael G.; Gebel, Dana A.; Killelea, Daniel R., E-mail: dkillelea@luc.edu [Department of Chemistry and Biochemistry, Loyola University Chicago, 1068 W. Sheridan Rd., Chicago, Illinois 60660 (United States)

2015-03-15

An electrochemical method using pulsed alternating current etching (PACE) to produce atomically sharp scanning tunneling microscopy (STM) tips is presented. An Arduino Uno microcontroller was used to control the number and duration of the alternating current (AC) pulses, allowing for ready optimization of the procedures for both Pt:Ir and W tips using a single apparatus. W tips prepared using constant and pulsed AC power were compared. Tips fashioned using PACE were sharper than those etched with continuous AC power alone. Pt:Ir tips were prepared with an initial coarse etching stage using continuous AC power followed by fine etching using PACE. The number and potential of the finishing AC pulses was varied and scanning electron microscope imaging was used to compare the results. Finally, tip quality using the optimized procedures was verified by UHV-STM imaging. With PACE, at least 70% of the W tips and 80% of the Pt:Ir tips were of sufficiently high quality to obtain atomically resolved images of HOPG or Ni(111)

Robust procedure for creating and characterizing the atomic structure of scanning tunneling microscope tips

Directory of Open Access Journals (Sweden)

Sumit Tewari

2017-11-01

Full Text Available Scanning tunneling microscopes (STM are used extensively for studying and manipulating matter at the atomic scale. In spite of the critical role of the STM tip, procedures for controlling the atomic-scale shape of STM tips have not been rigorously justified. Here, we present a method for preparing tips in situ while ensuring the crystalline structure and a reproducibly prepared tip structure up to the second atomic layer. We demonstrate a controlled evolution of such tips starting from undefined tip shapes.

Ductile crack growth simulation from near crack tip dissipated energy

International Nuclear Information System (INIS)

Marie, S.; Chapuliot, S.

2000-01-01

A method to calculate ductile tearing in both small scale fracture mechanics specimens and cracked components is presented. This method is based on an estimation of the dissipated energy calculated near the crack tip. Firstly, the method is presented. It is shown that a characteristic parameter G fr can be obtained, relevant to the dissipated energy in the fracture process. The application of the method to the calculation of side grooved crack tip (CT) specimens of different sizes is examined. The value of G fr is identified by comparing the calculated and experimental load line displacement versus crack extension curve for the smallest CT specimen. With this identified value, it is possible to calculate the global behaviour of the largest specimen. The method is then applied to the calculation of a pipe containing a through-wall thickness crack subjected to a bending moment. This pipe is made of the same material as the CT specimens. It is shown that it is possible to simulate the global behaviour of the structure including the prediction of up to 90-mm crack extension. Local terms such as the equivalent stress or the crack tip opening angle are found to be constant during the crack extension process. This supports the view that G fr controls the fields in the vicinity near the crack tip. (orig.)

Estimation of plasma ion saturation current and reduced tip arcing using Langmuir probe harmonics.

Science.gov (United States)

Boedo, J A; Rudakov, D L

2017-03-01

We present a method to calculate the ion saturation current, I sat , for Langmuir probes at high frequency (>100 kHz) using the harmonics technique and we compare that to a direct measurement of I sat . It is noted that the I sat estimation can be made directly by the ratio of harmonic amplitudes, without explicitly calculating T e . We also demonstrate that since the probe tips using the harmonic method are oscillating near the floating potential, drawing little power, this method reduces tip heating and arcing and allows plasma density measurements at a plasma power flux that would cause continuously biased tips to arc. A multi-probe array is used, with two spatially separated tips employing the harmonics technique and measuring the amplitude of at least two harmonics per tip. A third tip, located between the other two, measures the ion saturation current directly. We compare the measured and calculated ion saturation currents for a variety of plasma conditions and demonstrate the validity of the technique and its use in reducing arcs.

Customized atomic force microscopy probe by focused-ion-beam-assisted tip transfer

Energy Technology Data Exchange (ETDEWEB)

Wang, Andrew; Butte, Manish J., E-mail: manish.butte@stanford.edu [Department of Pediatrics, Division of Immunology, Allergy and Rheumatology, Stanford University, Stanford, California 94305 (United States)

2014-08-04

We present a technique for transferring separately fabricated tips onto tipless atomic force microscopy (AFM) cantilevers, performed using focused ion beam-assisted nanomanipulation. This method addresses the need in scanning probe microscopy for certain tip geometries that cannot be achieved by conventional lithography. For example, in probing complex layered materials or tall biological cells using AFM, a tall tip with a high-aspect-ratio is required to avoid artifacts caused by collisions of the tip's sides with the material being probed. We show experimentally that tall (18 μm) cantilever tips fabricated by this approach reduce squeeze-film damping, which fits predictions from hydrodynamic theory, and results in an increased quality factor (Q) of the fundamental flexural mode. We demonstrate that a customized tip's well-defined geometry, tall tip height, and aspect ratio enable improved measurement of elastic moduli by allowing access to low-laying portions of tall cells (T lymphocytes). This technique can be generally used to attach tips to any micromechanical device when conventional lithography of tips cannot be accomplished.

Precision Distances with the Tip of the Red Giant Branch Method

Science.gov (United States)

Beaton, Rachael Lynn; Carnegie-Chicago Hubble Program Team

2018-01-01

The Carnegie-Chicago Hubble Program aims to construct a distance ladder that utilizes old stellar populations in the outskirts of galaxies to produce a high precision measurement of the Hubble Constant that is independent of Cepheids. The CCHP uses the tip of the red giant branch (TRGB) method, which is a statistical measurement technique that utilizes the termination of the red giant branch. Two innovations combine to make the TRGB a competitive route to the Hubble Constant (i) the large-scale measurement of trigonometric parallax by the Gaia mission and (ii) the development of both precise and accurate means of determining the TRGB in both nearby (~1 Mpc) and distant (~20 Mpc) galaxies. Here I will summarize our progress in developing these standardized techniques, focusing on both our edge-detection algorithm and our field selection strategy. Using these methods, the CCHP has determined equally precise (~2%) distances to galaxies in the Local Group (< 1 Mpc) and across the Local Volume (< 20 Mpc). The TRGB is, thus, an incredibly powerful and straightforward means to determine distances to galaxies of any Hubble Type and, thus, has enormous potential for putting any number of astrophyiscal phenomena on absolute units.

Creative accomplishment of continuous TIP motor torque monitoring system in BWR plant

International Nuclear Information System (INIS)

Sun, C.H.; Li, I.N.; Liu, C.S.

1986-01-01

The Traveling In-core Probe (TIP) system is designed so delicate that the routine preventive maintenance - torque measurement is required to keep system operating properly. Normally, the torque measurement is performed by manually rotating torque wrench on the local TIP drive mechanism or using wattmeter during automatic operation. Whenever, either torque wrench or wattmeter measurement is performed, the high radiation exposure to maintenance personnel and mass manpower is expected. Because of this reason Taipower has developed a continuous TIP motor torque monitoring system to save manpower and minimize radiation exposure to maintenance personnel. This methods of TIP motor torque measurement will also predict TIP guide tube deterioration. (author)

Dielectrophoretic positioning of single nanoparticles on atomic force microscope tips for tip-enhanced Raman spectroscopy.

Science.gov (United States)

Leiterer, Christian; Deckert-Gaudig, Tanja; Singh, Prabha; Wirth, Janina; Deckert, Volker; Fritzsche, Wolfgang

2015-05-01

Tip-enhanced Raman spectroscopy, a combination of Raman spectroscopy and scanning probe microscopy, is a powerful technique to detect the vibrational fingerprint of molecules at the nanometer scale. A metal nanoparticle at the apex of an atomic force microscope tip leads to a large enhancement of the electromagnetic field when illuminated with an appropriate wavelength, resulting in an increased Raman signal. A controlled positioning of individual nanoparticles at the tip would improve the reproducibility of the probes and is quite demanding due to usually serial and labor-intensive approaches. In contrast to commonly used submicron manipulation techniques, dielectrophoresis allows a parallel and scalable production, and provides a novel approach toward reproducible and at the same time affordable tip-enhanced Raman spectroscopy tips. We demonstrate the successful positioning of an individual plasmonic nanoparticle on a commercial atomic force microscope tip by dielectrophoresis followed by experimental proof of the Raman signal enhancing capabilities of such tips. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Somatic embryogenesis in cell cultures of Glycine species.

Science.gov (United States)

Gamborg, O L; Davis, B P; Stahlhut, R W

1983-08-01

This report describes the development of procedures for the production of somatic embryos in cell cultures of Glycine species including soybean. The conditions for callus induction and initiation of rapidly growing cell suspension cultures were defined. Methods for inducing embryogenesis were tested on 16 lines of several Glycine species and cultivars of soybean. The SB-26 Culture of a G. soja gave the best results and was used in the experiments. Embryogenesis required the presence of picloram or 2,4-D. AMO 1618, CCC, PP-333 and Ancymidol enhanced the embryogenesis frequency. Plants of the G. soja (SB-26) were grown to maturity from seed-derived shoot tips. Characteristics of the plants are discussed.

Safety Tips: Basketball (For Parents)

Science.gov (United States)

... Staying Safe Videos for Educators Search English Español Safety Tips: Basketball KidsHealth / For Parents / Safety Tips: Basketball ... make sure they follow these tips. Why Basketball Safety Is Important Fortunately, very few basketball injuries are ...

Pictorial essay: trans-jugular intra-hepatic porto-systemic shunt (TIPS)

International Nuclear Information System (INIS)

Rao Anuradha, T.N.; Rastogi, H.; Pandey, U.C.

2001-01-01

TIPS is an interventional radiologic method of creating a portosystemic shunt by percutaneous means. It is a relatively new weapon in the armamentarium of the management of portal hypertension with variceal bleeding or intractable ascites. Using needles, angioplasty balloon catheters and expandable metallic stents, a shunt is established directly inside the liver parenchyma connecting a large hepatic vein with a main portal vein branch. Depending on the diameter of the expandable stent used, the created TIPS diverts various amounts of portal blood into the systemic circulation and results in significant portal decompression, cessation of hemorrhage from esophageal varices and resolution of ascites. TIPS is not only an effective and safe alternative to shunt surgery but is life saving in cases of variceal hemorrhage. The use of TIPS seems to be a valid alternative to surgery and has several advantages over either esophageal transection or surgical shunts. TIPS avoids a general anesthetic, laparotomy, and disruption of the hepatic venous system that may adversely affect subsequent hepatic transplantation. TIPS has been performed on patients without interfering with successful transplantation

A method to control the fabrication of etched optical fiber probes with nanometric tips

International Nuclear Information System (INIS)

Tao, Miaomiao; Gu, Ning; Huang, Lan; Jin, Yonglong

2010-01-01

Optical fiber probes with small size tips have attracted much interest in the areas of biosensor and near-field scanning optical microscopy. Chemical etching is a common useful method to fabricate such probes. But it is difficult to study or determine the etching time and control the shape of the fiber during the etching. In this work, a new method combining a fiber optic spectrometer with static chemical etching has been developed to fabricate optical fiber probe nanotips, where the fiber optic spectrometer is used to measure the optical signal during the etching. By calculating and analyzing the testing data, the relationship between the apex angle and the optical signal can be obtained. Accordingly, the process of fabricating optical fibers based on the optical signal can be controlled

Transjugular Intrahepatic Portosystemic Shunt (TIPS)

Medline Plus

Full Text Available ... the liver). Portal hypertension can also occur in children, although children are much less likely to require a TIPS. ... intentionally to solve the problem. Although extremely rare, children may also require a TIPS procedure. TIPS in ...

Comparison of Standard Culture-Based Method to Culture-Independent Method for Evaluation of Hygiene Effects on the Hand Microbiome.

Science.gov (United States)

Zapka, C; Leff, J; Henley, J; Tittl, J; De Nardo, E; Butler, M; Griggs, R; Fierer, N; Edmonds-Wilson, S

2017-03-28

Hands play a critical role in the transmission of microbiota on one's own body, between individuals, and on environmental surfaces. Effectively measuring the composition of the hand microbiome is important to hand hygiene science, which has implications for human health. Hand hygiene products are evaluated using standard culture-based methods, but standard test methods for culture-independent microbiome characterization are lacking. We sampled the hands of 50 participants using swab-based and glove-based methods prior to and following four hand hygiene treatments (using a nonantimicrobial hand wash, alcohol-based hand sanitizer [ABHS], a 70% ethanol solution, or tap water). We compared results among culture plate counts, 16S rRNA gene sequencing of DNA extracted directly from hands, and sequencing of DNA extracted from culture plates. Glove-based sampling yielded higher numbers of unique operational taxonomic units (OTUs) but had less diversity in bacterial community composition than swab-based sampling. We detected treatment-induced changes in diversity only by using swab-based samples ( P hand hygiene industry methods and for future hand microbiome studies. On the basis of our results and previously published studies, we propose recommendations for best practices in hand microbiome research. IMPORTANCE The hand microbiome is a critical area of research for diverse fields, such as public health and forensics. The suitability of culture-independent methods for assessing effects of hygiene products on microbiota has not been demonstrated. This is the first controlled laboratory clinical hand study to have compared traditional hand hygiene test methods with newer culture-independent characterization methods typically used by skin microbiologists. This study resulted in recommendations for hand hygiene product testing, development of methods, and future hand skin microbiome research. It also demonstrated the importance of inclusion of skin physiological metadata in

Advanced ceramic material for high temperature turbine tip seals

Science.gov (United States)

Solomon, N. G.; Vogan, J. W.

1978-01-01

Ceramic material systems are being considered for potential use as turbine blade tip gas path seals at temperatures up to 1370 1/4 C. Silicon carbide and silicon nitride structures were selected for study since an initial analysis of the problem gave these materials the greatest potential for development into a successful materials system. Segments of silicon nitride and silicon carbide materials over a range of densities, processed by various methods, a honeycomb structure of silicon nitride and ceramic blade tip inserts fabricated from both materials by hot pressing were tested singly and in combination. The evaluations included wear under simulated engine blade tip rub conditions, thermal stability, impact resistance, machinability, hot gas erosion and feasibility of fabrication into engine components. The silicon nitride honeycomb and low-density silicon carbide using a selected grain size distribution gave the most promising results as rub-tolerant shroud liners. Ceramic blade tip inserts made from hot-pressed silicon nitride gave excellent test results. Their behavior closely simulated metal tips. Wear was similar to that of metals but reduced by a factor of six.

Tip off the HAT- Epigenetic control of learning and memory by Drosophila Tip60.

Science.gov (United States)

Xu, Songjun; Elefant, Felice

2015-01-01

Disruption of epigenetic gene control mechanisms involving histone acetylation in the brain causes cognitive impairment, a debilitating hallmark of most neurodegenerative disorders. Histone acetylation regulates cognitive gene expression via chromatin packaging control in neurons. Unfortunately, the histone acetyltransferases (HATs) that generate such neural epigenetic signatures and their mechanisms of action remain unclear. Our recent findings provide insight into this question by demonstrating that Tip60 HAT action is critical for morphology and function of the mushroom body (MB), the learning and memory center in the Drosophila brain. We show that Tip60 is robustly produced in MB Kenyon cells and extending axonal lobes and that targeted MB Tip60 HAT loss results in axonal outgrowth disruption. Functional consequences of loss and gain of Tip60 HAT levels in the MB are evidenced by defects in memory. Tip60 ChIP-Seq analysis reveals enrichment for genes that function in cognitive processes and accordingly, key genes representing these pathways are misregulated in the Tip60 HAT mutant fly brain. Remarkably, increasing levels of Tip60 in the MB rescues learning and memory deficits resulting from Alzheimer's disease associated amyloid precursor protein (APP) induced neurodegeneration. Our studies highlight the potential of HAT activators as a therapeutic option for cognitive disorders.

Total Telephone Tips.

Science.gov (United States)

Corder, Lloyd E.; And Others

This manual of telephone behavior tips for business and sales professionals offers ways to handle the disgruntled caller and makes suggestions on topics relevant to the telephone. The manual is divided into the following sections and subsections: (1) Common Courtesy (staff tips, answering the telephone, screening calls, transferring calls, taking…

The effect of full coverage winglets on tip leakage aerodynamics over the plane tip in a turbine cascade

International Nuclear Information System (INIS)

Lee, Sang Woo; Cheon, Joo Hong; Zhang, Qiang

2014-01-01

Highlights: • The effect of full coverage (FC) winglets on tip leakage aerodynamics is tested. • A qualitative tip gap flow model for the FC winglet is suggested. • The FC winglet of w/p = 10.55% is considered an optimal one for the plane tip. -- Abstract: The effect of full coverage (FC) winglets on tip leakage aerodynamics over the plane tip in a turbine cascade has been investigated with the variation of winglet width (w) up to w/p = 15.83% for a tip gap-to-span (chord) ratio of h/s = 1.36% (h/c = 2.0%). A qualitative tip gap flow model for the FC winglet is suggested on the bases of the near-tip surface flow visualizations. As w/p increases, the passage vortex tends to be weakened meanwhile the tip leakage vortex becomes stronger and wall-jet-like. With an increment of w/p, the mass-averaged aerodynamic loss all over the measurement plane decreases steeply up to w/p = 10.55% and then becomes almost unchanged. Thus, the FC winglet of w/p = 10.55% is considered an optimal one for the plane tip. With respect to the baseline plane tip without winglet, the maximum mass-averaged loss reduction by installing the FC winglet on the plane tip is still somewhat smaller than that by employing the cavity squealer rim on the plane tip surface

Darkfield microspectroscopy of nanostructures on silver tip-enhanced Raman scattering probes

Energy Technology Data Exchange (ETDEWEB)

Itoh, Tamitake, E-mail: tamitake-itou@aist.go.jp [Nano-Bioanalysis Team, Health Technology Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Takamatsu, Kagawa 761-0395 (Japan); Yamamoto, Yuko S., E-mail: yamayulab@gmail.com [Research Fellow of the Japan Society for the Promotion of Science, Chiyoda, Tokyo 102-8472 (Japan); Department of Chemistry, School of Science and Technology, Kagawa University, Takamatsu, Kagawa 761-0396 (Japan); Suzuki, Toshiaki [UNISOKU Co. Ltd., 2-4-3 Kasugano, Hirakata, Osaka 573-0131 (Japan); Kitahama, Yasutaka; Ozaki, Yukihiro [Department of Chemistry, School of Science and Technology, Kwansei Gakuin University, Sanda, Hyogo 669-1337 (Japan)

2016-01-11

We report an evaluation method employing darkfield microspectroscopy for silver probes used in tip-enhanced Raman scattering (TERS). By adjusting the darkfield illumination, the diffracted light from the probe outlines disappears and the diffracted light from the surface nanostructures and tips of the probes appears as colorful spots. Scanning electron microscopy reveals that the spectral variations in these spots reflect the shapes of the surface nanostructures. The tip curvatures correlate to the spectral maxima of their spots. Temporal color changes in the spots indicate the deterioration due to the oxidation of the silver surfaces. These results show that the proposed method is useful for in situ evaluation of plasmonic properties of TERS probes.

Culture, Interface Design, and Design Methods for Mobile Devices

Science.gov (United States)

Lee, Kun-Pyo

Aesthetic differences and similarities among cultures are obviously one of the very important issues in cultural design. However, ever since products became knowledge-supporting tools, the visible elements of products have become more universal so that the invisible parts of products such as interface and interaction are getting more important. Therefore, the cultural design should be extended to the invisible elements of culture like people's conceptual models beyond material and phenomenal culture. This chapter aims to explain how we address the invisible cultural elements in interface design and design methods by exploring the users' cognitive styles and communication patterns in different cultures. Regarding cultural interface design, we examined users' conceptual models while interacting with mobile phone and website interfaces, and observed cultural difference in performing tasks and viewing patterns, which appeared to agree with cultural cognitive styles known as Holistic thoughts vs. Analytic thoughts. Regarding design methods for culture, we explored how to localize design methods such as focus group interview and generative session for specific cultural groups, and the results of comparative experiments revealed cultural difference on participants' behaviors and performance in each design method and led us to suggest how to conduct them in East Asian culture. Mobile Observation Analyzer and Wi-Pro, user research tools we invented to capture user behaviors and needs especially in their mobile context, were also introduced.

Tip clearance effect on through-flow and performance of a centrifugal compressor

International Nuclear Information System (INIS)

Eum, Hark Jin; Kang, Young Seok; Kang, Shin Hyoung

2004-01-01

Numerical simulations have been performed to investigate tip clearance effect on through-flow and performance of a centrifugal compressor which has the same configuration of impeller with six different tip clearances. Secondary flow and loss distribution have been surveyed to understand the flow mechanism due to the tip clearance. Tip leakage flow strongly interacts with mainstream flow and considerably changes the secondary flow and the loss distribution inside the impeller passage. A method has been described to quantitatively estimate the tip clearance effect on the performance drop and the efficiency drop. The tip clearance has caused specific work reduction and additional entropy generation. The former, which is called inviscid loss, is independent of any internal loss and the latter, which is called viscous loss, is dependent on every loss in the flow passage. Two components equally affected the performance drop as the tip clearances were small, while the efficiency drop was influenced by the viscous component alone. The additional entropy generation was modeled with all the kinetic energy of the tip leakage flow. Therefore, the present paper can provide how to quantitatively estimate the tip clearance effect on the performance and efficiency

Design of characteristic parameters for controlling tungsten tip profile during electrochemical etching

Energy Technology Data Exchange (ETDEWEB)

Le Duy Cuong; Duong, Thanh Hung; Kim, Huyn Chul [Inje University, Gimhae (Korea, Republic of)

2014-05-15

Micro/nano-scale tungsten tips fabricated by electrochemical etching have many diverse industrial applications. The characteristic parameters of the tungsten tip profile include apex radius, taper angle, and aspect ratio. These parameters are governed by many factors including applied voltage, concentration of the electrolyte (potassium hydroxide) solution, and diameter of the inner gold ring. However, a systematic investigation with the aim of determining the best conditions for fabricating micro/nano-scale tips with desired profiles has not been carried out yet. This study is aimed at obtaining controllable tungsten tip -particularly with respect to the radius of curvature and aspect ratio of tips (taper angle)-by altering the experimental conditions. A series of experiments were executed and the results were aggregated and analyzed using response surface methodology in order to identify the relationships between the tungsten tip characteristics and input parameters. The method proposed herein would prove to be suitable for a variety of applications in industries that require tungsten tips with a specific profile.

Design of characteristic parameters for controlling tungsten tip profile during electrochemical etching

International Nuclear Information System (INIS)

Le Duy Cuong; Duong, Thanh Hung; Kim, Huyn Chul

2014-01-01

Micro/nano-scale tungsten tips fabricated by electrochemical etching have many diverse industrial applications. The characteristic parameters of the tungsten tip profile include apex radius, taper angle, and aspect ratio. These parameters are governed by many factors including applied voltage, concentration of the electrolyte (potassium hydroxide) solution, and diameter of the inner gold ring. However, a systematic investigation with the aim of determining the best conditions for fabricating micro/nano-scale tips with desired profiles has not been carried out yet. This study is aimed at obtaining controllable tungsten tip -particularly with respect to the radius of curvature and aspect ratio of tips (taper angle)-by altering the experimental conditions. A series of experiments were executed and the results were aggregated and analyzed using response surface methodology in order to identify the relationships between the tungsten tip characteristics and input parameters. The method proposed herein would prove to be suitable for a variety of applications in industries that require tungsten tips with a specific profile

Influence of the atomic force microscope tip on the multifractal analysis of rough surfaces

International Nuclear Information System (INIS)

Klapetek, Petr; Ohlidal, Ivan; Bilek, Jindrich

2004-01-01

In this paper, the influence of atomic force microscope tip on the multifractal analysis of rough surfaces is discussed. This analysis is based on two methods, i.e. on the correlation function method and the wavelet transform modulus maxima method. The principles of both methods are briefly described. Both methods are applied to simulated rough surfaces (simulation is performed by the spectral synthesis method). It is shown that the finite dimensions of the microscope tip misrepresent the values of the quantities expressing the multifractal analysis of rough surfaces within both the methods. Thus, it was concretely shown that the influence of the finite dimensions of the microscope tip changed mono-fractal properties of simulated rough surface to multifractal ones. Further, it is shown that a surface reconstruction method developed for removing the negative influence of the microscope tip does not improve the results obtained in a substantial way. The theoretical procedures concerning both the methods, i.e. the correlation function method and the wavelet transform modulus maxima method, are illustrated for the multifractal analysis of randomly rough gallium arsenide surfaces prepared by means of the thermal oxidation of smooth gallium arsenide surfaces and subsequent dissolution of the oxide films

A Rotor Tip Vortex Tracing Algorithm for Image Post-Processing

Science.gov (United States)

Overmeyer, Austin D.

2015-01-01

A neurite tracing algorithm, originally developed for medical image processing, was used to trace the location of the rotor tip vortex in density gradient flow visualization images. The tracing algorithm was applied to several representative test images to form case studies. The accuracy of the tracing algorithm was compared to two current methods including a manual point and click method and a cross-correlation template method. It is shown that the neurite tracing algorithm can reduce the post-processing time to trace the vortex by a factor of 10 to 15 without compromising the accuracy of the tip vortex location compared to other methods presented in literature.

Homogeneous nucleation of water in argon. Nucleation rate computation from molecular simulations of TIP4P and TIP4P/2005 water model.

Science.gov (United States)

Dumitrescu, Lucia R; Smeulders, David M J; Dam, Jacques A M; Gaastra-Nedea, Silvia V

2017-02-28

Molecular dynamics (MD) simulations were conducted to study nucleation of water at 350 K in argon using TIP4P and TIP4P/2005 water models. We found that the stability of any cluster, even if large, strongly depends on the energetic interactions with its vicinity, while the stable clusters change their composition almost entirely during nucleation. Using the threshold method, direct nucleation rates are obtained. Our nucleation rates are found to be 1.08×10 27 cm -3 s -1 for TIP4P and 2.30×10 27 cm -3 s -1 for TIP4P/2005. The latter model prescribes a faster dynamics than the former, with a nucleation rate two times larger due to its higher electrostatic charges. The non-equilibrium water densities derived from simulations and state-of-art equilibrium parameters from Vega and de Miguel [J. Chem. Phys. 126, 154707 (2007)] are used for the classical nucleation theory (CNT) prediction. The CNT overestimates our results for both water models, where TIP4P/2005 shows largest discrepancy. Our results complement earlier data at high nucleation rates and supersaturations in the Hale plot [Phys. Rev. A 33, 4156 (1986)], and are consistent with MD data on the SPC/E and the TIP4P/2005 model.

Proton MR spectroscopy of the brain in patients treated with tips

Energy Technology Data Exchange (ETDEWEB)

Hamuro, M.; Nakamura, K.; Matsuoka, T.; Kaminou, T.; Higashida, M.; Yamada, R. [Osaka City Univ. Medical School (Japan). Dept. of Radiology

2000-11-01

To evaluate the utility of proton MR spectroscopy (MRS) for the early detection of hepatic encephalopathy (HE) after transjugular intrahepatic portosystemic shunting (TIPS). Material and Methods: Six patients, who underwent TIPS for treatment of portal hypertension, were examined by MRS 1 week before and 1 week after TIPS. They were simultaneously clinically examined for number connection test, blood NH{sub 3} level, liver function test and the Fischer ratio. Result: Three of 6 patients showed overt HE 1 to 5 weeks after TIPS and the other 3 patients did not show overt HE. The overt HE group showed the larger ratio of the amounts of glutamine and glutamate/myoinositol (Glx/MI) than that of non-overt HE group (p<0.05). Conclusion: The Glx/MI ratio estimated by MRS was useful for early detection of HE after TIPS.

Proton MR spectroscopy of the brain in patients treated with tips

International Nuclear Information System (INIS)

Hamuro, M.; Nakamura, K.; Matsuoka, T.; Kaminou, T.; Higashida, M.; Yamada, R.

2000-01-01

To evaluate the utility of proton MR spectroscopy (MRS) for the early detection of hepatic encephalopathy (HE) after transjugular intrahepatic portosystemic shunting (TIPS). Material and Methods: Six patients, who underwent TIPS for treatment of portal hypertension, were examined by MRS 1 week before and 1 week after TIPS. They were simultaneously clinically examined for number connection test, blood NH 3 level, liver function test and the Fischer ratio. Result: Three of 6 patients showed overt HE 1 to 5 weeks after TIPS and the other 3 patients did not show overt HE. The overt HE group showed the larger ratio of the amounts of glutamine and glutamate/myoinositol (Glx/MI) than that of non-overt HE group (p<0.05). Conclusion: The Glx/MI ratio estimated by MRS was useful for early detection of HE after TIPS

Microfabricated microneedle with porous tip for drug delivery

Science.gov (United States)

Ji, Jing; Tay, Francis E. H.; Miao, Jianmin; Iliescu, Ciprian

2006-05-01

This paper presents a novel approach to fabrication of a silicon microneedle array with porous tips. Dry etching technology with SF6/O2 gas by STS's inductively coupled plasma (ICP) etch tool was used to achieve the pyramidal needle structure. A thin silicon nitride layer was deposited after a thick photoresist layer was coated and reflowed at 120 °C. The silicon nitride layer and residual photoresist on the tips of the pyramidal structures were removed using reactive ion etching (RIE). Electrochemical etching in MeCN/HF was carried out to generate porous silicon on the tips of the microneedles. The fabricated microneedle array has potential applications in drug delivery, since the porous tips can be loaded with a high molecular weight drug. Analytic solutions to the critical loadings of the fabricated microneedle structure are also presented. The variations of the square cross-section were expressed as a function of the axial coordinate to analyze the bending normal stress and critical buckling loading. This analytic method can also be used for other microneedle structures with different cross-sections.

Rapid tryptic mapping using enzymatically active mass spectrometer probe tips

Energy Technology Data Exchange (ETDEWEB)

Dogruel, D.; Williams, P.; Nelson, R.W. [Arizona State Univ., Tempe, AZ (United States)

1995-12-01

A method has been developed for rapid, sensitive, and accurate tryptic mapping of polypeptides using matrix-assisted laser desorption/ionization time-of-flight mass analysis. The technique utilizes mass spectrometer probe tips which have been activated through the covalent immobilization of trypsin. The enzymatically active probe tips were used for the tryptic mapping of chicken egg lysozyme and the results compared with those obtained using either free trypsin or agarose-immobilized trypsin. A significant increase in the overall sensitivity of the process was observed using the active probe tips, as well as the production of more characteristic proteolytic fragments and the elimination of background signals due to the autolysis of the trypsin. Further, probe tip digestions were found to be rapid and convenient. 19 refs., 6 figs., 2 tabs.

Diagnostic accuracy of semi-quantitative and quantitative culture techniques for the diagnosis of catheter-related infections in newborns and molecular typing of isolated microorganisms.

Science.gov (United States)

Riboli, Danilo Flávio Moraes; Lyra, João César; Silva, Eliane Pessoa; Valadão, Luisa Leite; Bentlin, Maria Regina; Corrente, José Eduardo; Rugolo, Ligia Maria Suppo de Souza; da Cunha, Maria de Lourdes Ribeiro de Souza

2014-05-22

Catheter-related bloodstream infections (CR-BSIs) have become the most common cause of healthcare-associated bloodstream infections in neonatal intensive care units (ICUs). Microbiological evidence implicating catheters as the source of bloodstream infection is necessary to establish the diagnosis of CR-BSIs. Semi-quantitative culture is used to determine the presence of microorganisms on the external catheter surface, whereas quantitative culture also isolates microorganisms present inside the catheter. The main objective of this study was to determine the sensitivity and specificity of these two techniques for the diagnosis of CR-BSIs in newborns from a neonatal ICU. In addition, PFGE was used for similarity analysis of the microorganisms isolated from catheters and blood cultures. Semi-quantitative and quantitative methods were used for the culture of catheter tips obtained from newborns. Strains isolated from catheter tips and blood cultures which exhibited the same antimicrobial susceptibility profile were included in the study as positive cases of CR-BSI. PFGE of the microorganisms isolated from catheters and blood cultures was performed for similarity analysis and detection of clones in the ICU. A total of 584 catheter tips from 399 patients seen between November 2005 and June 2012 were analyzed. Twenty-nine cases of CR-BSI were confirmed. Coagulase-negative staphylococci (CoNS) were the most frequently isolated microorganisms, including S. epidermidis as the most prevalent species (65.5%), followed by S. haemolyticus (10.3%), yeasts (10.3%), K. pneumoniae (6.9%), S. aureus (3.4%), and E. coli (3.4%). The sensitivity of the semi-quantitative and quantitative techniques was 72.7% and 59.3%, respectively, and specificity was 95.7% and 94.4%. The diagnosis of CR-BSIs based on PFGE analysis of similarity between strains isolated from catheter tips and blood cultures showed 82.6% sensitivity and 100% specificity. The semi-quantitative culture method showed higher

CFD Analysis of Scale Effects on Conventional and Tip-Modified Propellers

DEFF Research Database (Denmark)

Shin, Keun Woo; Andersen, Poul

2017-01-01

Full-scale propeller performance is traditionally predictedby scaling model-scale test results, but the traditionalscaling methods do not take into account hydrodynamicdistinctions of tip-modified propellers in full-scaleperformance. An open-water CFD analysis is made onscale effects of tip...... the transition model shows that laminar and transitionalflow modeling is crucial in model-scale computations.Grid-independent solutions at model and full scale areachieved by grid verification studies. The CFD analysis of scale effects shows that theefficiency gain of the tip-modified propeller is increasedat...

CFD analysis of cloud cavitation on three tip-modified propellers with systematically varied tip geometry

DEFF Research Database (Denmark)

Shin, K. W.; Andersen, Poul

2015-01-01

The blade tip loading is often reduced as an effort to restrain sheet and tip vortex cavitation in the design of marine propellers. This CFD analysis demonstrates that an excessive reduction of the tip loading can cause cloud cavitation responsible for much of noise and surface erosion. Detached...

Tips on Blood Testing

Science.gov (United States)

... Test Pain, Discomfort and Anxiety Tips to Help Children through Their Medical Tests Tips to Help the Elderly through Their Medical Tests Find Us On Social Media: Facebook Twitter Google Plus Footer Menu Home About ...

Turbine blade tip clearance measurement using a skewed dual-beam fiber optic sensor

Science.gov (United States)

Ye, De-chao; Duan, Fa-jie; Guo, Hao-tian; Li, Yangzong; Wang, Kai

2012-08-01

Optimization and active control of the tip clearance of turbine blades has been identified as a key to improve fuel efficiency, reduce emission, and increase service life of the engine. However, reliable and real-time tip clearance measurement is difficult due to the adverse environmental conditions that are typically found in a turbine. We describe a dual-beam fiber optic measurement system that can measure the tip timing and tip clearance simultaneously. Because the tip timing information is used to calculate the tip clearance, the method is insensitive to the signal intensity variation caused by fluctuations in environmental conditions such as light source instability, contamination, and blade tip imperfection. The system was calibrated and tested using experimental rotors. The test results indicated a high resolution of 4.5 μm and measurement accuracy of ±20 μm over the rotation speed range of 2000 to 10,000 rpm.

Value of Micronester coils in port-catheter implantation for continuous hepatic arterial infusion chemotherapy with fixed catheter tip method

International Nuclear Information System (INIS)

Yamagami, Takuji; Kato, Takeharu; Hirota, Tatsuya; Yoshimatsu, Rika; Matsumoto, Tomohiro; Nishimura, Tsunehiko; White, Robert I.

2008-01-01

To retrospectively evaluate the use of Micronester coils in port-catheter implantation with the fixed catheter tip method in comparison with other previously used coils. The cohort of this study was 143 consecutive patients with unresectable advanced liver cancer for whom a port-catheter system was percutaneously implanted. In the most recent 32 patients, Micronester coils were used for catheter tip fixation. Details of embolic agents for fixation, persistent blood flow beyond the distal end of the indwelling catheter, and complications were compared between cases without and with Micronester coils. In all, percutaneous port-catheter placement was successful. Mean number of coils used for fixation was 4.2 without Micronester coils vs. 2.5 with Micronester coils. N-butyl cyanoacrylate (NBCA)-Lipiodol was additionally used for catheter tip fixation in 85.6% of 111 procedures without Micronester coils and in 50% of 32 using Micronester coils. The gastroduodenal artery beyond the distal end was not detected at the final examination after any procedure. Catheter dislocation occurred in five and hepatic arterial obstruction or severe stenosis in eight. The number of coils used and necessity of NBCA-Lipiodol could be decreased with usage of Micronester coils without decreasing fixation ability compared to other coils. (orig.)

Tip preparation for usage in an ultra-low temperature UHV scanning tunneling microscope

Directory of Open Access Journals (Sweden)

S. Ernst, S. Wirth, M. Rams, V. Dolocan and F. Steglich

2007-01-01

Full Text Available This work deals with the preparation and characterization of tungsten tips for the use in UHV low-temperature scanning tunneling microscopy and spectroscopy (STM and STS, respectively. These specific environments require in situ facilities for tip conditioning, for further sharpening of the tips, as well as for reliable tip characterization. The implemented conditioning methods include direct resistive annealing, annealing by electron bombardment, and self-sputtering with noble gas ions. Moreover, results from in situ tip characterization by field emission and STM experiments were compared to ex situ scanning electron microscopy. Using the so-prepared tips, high resolution STM images and tunneling spectra were obtained in a temperature range from ambient down to 350 mK, partially with applied magnetic field, on a variety of materials.

Preparation of Chemically Etched Tips for Ambient Instructional Scanning Tunneling Microscopy

Science.gov (United States)

Zaccardi, Margot J.; Winkelmann, Kurt; Olson, Joel A.

2010-01-01

A first-year laboratory experiment that utilizes concepts of electrochemical tip etching for scanning tunneling microscopy (STM) is described. This experiment can be used in conjunction with any STM experiment. Students electrochemically etch gold STM tips using a time-efficient method, which can then be used in an instructional grade STM that…

Refined tip preparation by electrochemical etching and ultrahigh vacuum treatment to obtain atomically sharp tips for scanning tunneling microscope and atomic force microscope

International Nuclear Information System (INIS)

Hagedorn, Till; Ouali, Mehdi El; Paul, William; Oliver, David; Miyahara, Yoichi; Gruetter, Peter

2011-01-01

A modification of the common electrochemical etching setup is presented. The described method reproducibly yields sharp tungsten tips for usage in the scanning tunneling microscope and tuning fork atomic force microscope. In situ treatment under ultrahigh vacuum (p ≤10 -10 mbar) conditions for cleaning and fine sharpening with minimal blunting is described. The structure of the microscopic apex of these tips is atomically resolved with field ion microscopy and cross checked with field emission.

Functionalization of gold and nanocrystalline diamond atomic force microscope tips for single molecule force spectroscopy

Science.gov (United States)

Drew, Michael E.

The atomic force microscope (AFM) has fueled interest in nanotechnology because of its ability to image surfaces at the nanometer level and act as a molecular force sensor. Functionalization of the surface of an AFM tip surface in a stable, controlled manner expands the capabilities of the AFM and enables additional applications in the fields of single molecule force spectroscopy and nanolithography. Two AFM tip functionalizations are described: the assembly of tripodal molecular tips onto gold AFM tips and the photochemical attachment of terminal alkenes to nanocrystalline diamond (NCD) AFM tips. Two separate tripodal molecules with different linker lengths and a monopodal molecule terminated with biotin were synthesized to attach to a gold AFM tip for single molecule force spectroscopy. The immobilization of these molecules was examined by contact angle measurements, spectroscopic ellipsometry, infrared, and near edge x-ray absorption fine structure (NEXAFS) spectroscopy. All three molecules displayed rupture forces that agreed with previously reported values for the biotin--avidin rupture. The tripodal molecular tip displayed narrower distribution in their force histograms than the monopodal molecular tip. The performance of the tripodal molecular tip was compared to the monopodal molecular tip in single molecule force spectroscopy studies. Over repeated measurements, the distribution of forces for the monopodal molecular tip shifted to lower forces, whereas the distribution for the tripodal molecular tip remained constant throughout. Loading rate dependence and control experiments further indicated that the rupture forces of the tripod molecular tips were specific to the biotin--NeutrAvidin interaction. The second functionalization method used the photochemical attachment of undecylenic acid to NCD AFM tips. The photochemical attachment of undecylenic acid to hydrogen-terminated NCD wafer surfaces was investigated by contact angle measurements, x

Tip moth control and loblolly pine growth in intensive pine culture: four year results

Science.gov (United States)

David L. Kulhavy; Jimmie L. Yeiser; L. Allen Smith

2006-01-01

Twenty-two treatments replicated four times were applied to planted loblolly pine, Pinus taeda L., on bedded industrial forest land in east Texas for measurement of growth impact of Nantucket pine tip moth (NPTM), Rhyacionia frustrana Comstock, and effects on pine growth over 2 years. Treatments were combinations of Velpar®,...

ADHD: Tips to Try

Science.gov (United States)

... Staying Safe Videos for Educators Search English Español ADHD: Tips to Try KidsHealth / For Teens / ADHD: Tips to Try Print en español TDAH: Consejos que puedes probar ADHD , short for attention deficit hyperactivity disorder , is a ...

High efficiency protoplast isolation from in vitro cultures and hairy ...

African Journals Online (AJOL)

In vitro cultures of the medicinal plant Maesa lanceolata were established to enable the cultivation of plant material for the production of protoplasts. Callus cultures were initiated using leaves collected from shoot cultures and the root tips from hairy root cultures obtained upon Agrobacterium rhizogenes transformation.

Magnet pole tips

Science.gov (United States)

Thorn, Craig E.; Chasman, Chellis; Baltz, Anthony J.

1984-04-24

An improved magnet which more easily provides a radially increasing magnetic field, as well as reduced fringe field and requires less power for a given field intensity. The subject invention comprises a pair of spaced, opposed magnetic poles which further comprise a pair of pole roots, each having a pole tip attached to its center. The pole tips define the gap between the magnetic poles and at least a portion of each pole tip is separated from its associated pole root. The separation begins at a predetermined distance from the center of the pole root and increases with increasing radial distance while being constant with azimuth within that portion. Magnets in accordance with the subject invention have been found to be particularly advantageous for use in large isochronous cyclotrons.

Method of measurement of near tip field of fast propagating cracks by means of interferometry; Hikari kansho ni yoru kosoku shinten kiretsu sentanbu no oryokuba keisokuho

Energy Technology Data Exchange (ETDEWEB)

Suzuki, s.; Miyazaki, F. [Toyohashi University of Technology, Aichi (Japan); Nakane, K. [Nitto Denko Corp., Osaka (Japan)

1994-12-15

The measurement by an interference method at the tip of fast propagating cracks was investigated. To clarify the direction-dependent problem of dynamic cracks in a higher-order term, a high-precision stress field must be measured in every direction. In this method, the propagated interference fringes near the crack tip are shot at a speed of some hundreds of m/sec, and the coefficient of dynamic stress extension is obtained from the expression given when the number of fringes (`m`) in the interferences fringes is differentiated partially. The information below was obtained. The stress field in every direction can be analyzed by the interference method. However, the interference fringes in an area of absolute {theta} < 120{degree} are radially spread from the crack tip, so the precision of the interference fringes in the {gamma} direction deteriorates. In this area, the above partial differential is higher in precision when {alpha}m/{alpha}{theta} is used instead of {alpha}m/{alpha}{gamma}. The stress extension coefficient obtained by a caustic method can be verified if a stress field of {theta} = {plus_minus}72{degree} is analyzed by the interference method. By shooting in this optical system, the COD measurement, the K-value measurement of caustic light, and the stress field measurement by an interference method can be done simultaneously. 17 refs., 11 figs.

TIP-1 translocation onto the cell plasma membrane is a molecular biomarker of tumor response to ionizing radiation.

Directory of Open Access Journals (Sweden)

Hailun Wang

2010-08-01

Full Text Available Tumor response to treatment has been generally assessed with anatomic and functional imaging. Recent development of in vivo molecular and cellular imaging showed promise in time-efficient assessment of the therapeutic efficacy of a prescribed regimen. Currently, the in vivo molecular imaging is limited with shortage of biomarkers and probes with sound biological relevance. We have previously shown in tumor-bearing mice that a hexapeptide (HVGGSSV demonstrated potentials as a molecular imaging probe to distinguish the tumors responding to ionizing radiation (IR and/or tyrosine kinase inhibitor treatment from those of non-responding tumors.In this study we have studied biological basis of the HVGGSSV peptide binding within the irradiated tumors by use of tumor-bearing mice and cultured cancer cells. The results indicated that Tax interacting protein 1 (TIP-1, also known as Tax1BP3 is a molecular target that enables the selective binding of the HVGGSSV peptide within irradiated xenograft tumors. Optical imaging and immunohistochemical staining indicated that a TIP-1 specific antibody demonstrated similar biodistribution as the peptide in tumor-bearing mice. The TIP-1 antibody blocked the peptide from binding within irradiated tumors. Studies on both of human and mouse lung cancer cells showed that the intracellular TIP-1 relocated to the plasma membrane surface within the first few hours after exposure to IR and before the onset of treatment associated apoptosis and cell death. TIP-1 relocation onto the cell surface is associated with the reduced proliferation and the enhanced susceptibility to the subsequent IR treatment.This study by use of tumor-bearing mice and cultured cancer cells suggested that imaging of the radiation-inducible TIP-1 translocation onto the cancer cell surface may predict the tumor responsiveness to radiation in a time-efficient manner and thus tailor radiotherapy of cancer.

Comparison of Standard Culture-Based Method to Culture-Independent Method for Evaluation of Hygiene Effects on the Hand Microbiome

Science.gov (United States)

Leff, J.; Henley, J.; Tittl, J.; De Nardo, E.; Butler, M.; Griggs, R.; Fierer, N.

2017-01-01

ABSTRACT Hands play a critical role in the transmission of microbiota on one’s own body, between individuals, and on environmental surfaces. Effectively measuring the composition of the hand microbiome is important to hand hygiene science, which has implications for human health. Hand hygiene products are evaluated using standard culture-based methods, but standard test methods for culture-independent microbiome characterization are lacking. We sampled the hands of 50 participants using swab-based and glove-based methods prior to and following four hand hygiene treatments (using a nonantimicrobial hand wash, alcohol-based hand sanitizer [ABHS], a 70% ethanol solution, or tap water). We compared results among culture plate counts, 16S rRNA gene sequencing of DNA extracted directly from hands, and sequencing of DNA extracted from culture plates. Glove-based sampling yielded higher numbers of unique operational taxonomic units (OTUs) but had less diversity in bacterial community composition than swab-based sampling. We detected treatment-induced changes in diversity only by using swab-based samples (P hand hygiene industry methods and for future hand microbiome studies. On the basis of our results and previously published studies, we propose recommendations for best practices in hand microbiome research. PMID:28351915

Culture Positivity of CVCs Used for TPN: Investigation of an Association with Catheter-Related Infection and Comparison of Causative Organisms between ICU and Non-ICU CVCs

Directory of Open Access Journals (Sweden)

Criona Walshe

2012-01-01

Full Text Available A relationship between central venous catheter (CVC tip colonisation and catheter-related blood-stream infection (CRBSI has been suggested. We examined culture positivity of CVC tips (colonised and infected CVCs in a total parenteral nutrition (TPN population. Our aims were to define the relationship between culture positivity and CRBSI, and to compare causative organisms between culture positive and CRBSI CVCS, and between ward and ICU CVCs. All patients receiving TPN via non-tunnelled CVCs during the study (1997–2009 were included. All CVC tips were analysed. Data were collated contemporaneously. A TPN audit committee determined whether CVC tip culture positivity reflected colonisation/CRBSI using CDC criteria. 1,392 patients received TPN via 2,565 CVCs over 15,397 CVC days. 25.4% of CVCs tips were culture positive, of these 32% developed CRBSI. There was a nonsignificant trend of higher Gram negative Bacilli isolation in ICU CVCs (=0.1, ward CVCs were associated with higher rates of staphylococcal isolation (=0.01. A similar pattern of organisms were cultured from CRBSI and culture positive CVCs. The consistent relationship between CRBSI and culture positive CVCs, and similar pattern of causative organisms further supports an aetiological relationship between culture positive CVC tips and CRBSI, supporting the contention that CVC culture-positivity may be a useful surrogate marker for CRBSI rates.

Reliable lateral manipulation of a single Ag adatom on a Ag(1 1 1) surface with a trimer-apex tip

International Nuclear Information System (INIS)

Xie Yiqun; Shi Wangzhou; Du Guoping

2009-01-01

We study the reliability of the lateral manipulation of a single Ag adatom on a Ag(1 1 1) surface with the single-atom and trimer-apex tips based on molecular statics simulations using surface embedded-atom-method potential. The dependence of the manipulation reliability on tip height and orientation is investigated. For the single-atom tip the manipulation reliability increases monotonically with decreasing tip height, which is owing to the strengthened lateral tip-adatom interaction as the tip height lowers. For the trimer-apex tip, the manipulation reliability is sensitive to the tip orientation in the lower tip-height range, while in the higher tip-height range the manipulation reliability is independent of the tip orientation and moreover can be greatly improved due to the strong vertical attraction of the tip on the adatom as compared to the single-atom tip. We also compare these results to those for manipulating single Cu adatoms on the Cu(1 1 1) surface, reveal the underlying physics, and propose the method to improve the manipulation reliability for different systems.

The awareness of employees in safety culture through the improved nuclear safety culture evaluation method

Energy Technology Data Exchange (ETDEWEB)

Kim, Young Ga; Sung, Chan Ho; Jung, Yeon Sub [KHNP Central Research Institute, Daejeon (Korea, Republic of)

2012-10-15

After the Chernobyl nuclear accident in 1986, nuclear safety culture terminology was at first introduced emphasizing the importance of employees' attitude and organizational safety. The concept of safety culture was spread by INSAG 4 published in 1991. From that time, IAEA had provided the service of ASCOT for the safety culture assessment. However, many people still are thinking that safety culture is abstract and is not clear. It is why the systematic and reliable assessment methodology was not developed. Assessing safety culture is to identify what is the basic assumption for any organization to accept unconsciously. Therefore, it is very difficult to reach a meaningful conclusion by a superficial investigation alone. KHNP had been doing the safety culture assessment which was based on ASCOT methodology every 2 years. And this result had contributed to improving safety culture. But this result could not represent the level of organization's safety culture due to the limitation of method. So, KHNP has improved the safety culture method by benchmarking the over sea assessment techniques in 2011. The effectiveness of this improved methodology was validated through a pilot assessment. In this paper, the level of employees' safety culture awareness was analyzed by the improved method and reviewed what is necessary for the completeness and objectivity of the nuclear safety culture assessment methodology.

The awareness of employees in safety culture through the improved nuclear safety culture evaluation method

International Nuclear Information System (INIS)

Kim, Young Ga; Sung, Chan Ho; Jung, Yeon Sub

2012-01-01

After the Chernobyl nuclear accident in 1986, nuclear safety culture terminology was at first introduced emphasizing the importance of employees' attitude and organizational safety. The concept of safety culture was spread by INSAG 4 published in 1991. From that time, IAEA had provided the service of ASCOT for the safety culture assessment. However, many people still are thinking that safety culture is abstract and is not clear. It is why the systematic and reliable assessment methodology was not developed. Assessing safety culture is to identify what is the basic assumption for any organization to accept unconsciously. Therefore, it is very difficult to reach a meaningful conclusion by a superficial investigation alone. KHNP had been doing the safety culture assessment which was based on ASCOT methodology every 2 years. And this result had contributed to improving safety culture. But this result could not represent the level of organization's safety culture due to the limitation of method. So, KHNP has improved the safety culture method by benchmarking the over sea assessment techniques in 2011. The effectiveness of this improved methodology was validated through a pilot assessment. In this paper, the level of employees' safety culture awareness was analyzed by the improved method and reviewed what is necessary for the completeness and objectivity of the nuclear safety culture assessment methodology

Lightning Safety Tips and Resources

Science.gov (United States)

... Services Careers Contact Us Glossary Safety National Program Lightning Safety Tips and Resources Weather.gov > Safety > Lightning Safety Tips and Resources Lightning Resources Lightning strikes ...

Tip Cells in Angiogenesis

NARCIS (Netherlands)

M.G. Dallinga (Marchien); S.E.M. Boas (Sonja); I. Klaassen (Ingeborg); R.M.H. Merks (Roeland); C.J.F. van Noorden; R.O. Schlingemann (Reinier)

2015-01-01

htmlabstractIn angiogenesis, the process in which blood vessel sprouts grow out from a pre-existing vascular network, the so-called endothelial tip cells play an essential role. Tip cells are the leading cells of the sprouts; they guide following endothelial cells and sense their environment for

Tip model of cold fission

International Nuclear Information System (INIS)

Goennenwein, F.; Boersig, B.

1991-01-01

Cold fission is defined to be the limiting case of nuclear fission where virtually all of the available energy is converted into the total kinetic energy of the fragments. The fragments have, therefore, to be born in or at least close to their respective ground states. Starting from the viewpoint that cold fission corresponds to most compact scission configurations, energy constraints have been exploited to calculate minimum tip distances between the two nascent fragments in binary fission. Crucial input parameters to this tip model of cold fission are the ground-state deformations of fragment nuclei. It is shown that the minimum tip distances being compatible with energy conservation vary strongly with both the mass and charge fragmentation of the fission prone nucleus. The tip distances refer to nuclei with equivalent sharp surfaces. In keeping with the size of the surface width of leptodermous nuclei, only configurations where the tip distances are smaller than a few fm may be considered as valid scission configurations. From a comparison with experimental data on cold fission this critical tip distance appears to be 3.0 fm for the model parameters chosen. Whenever the model calculation yields tip distances being smaller than the critical value, a necessary condition for attaining cold fission is considered to be fulfilled. It is shown that this criterion allows to understand in fair agreement with experiment which mass fragmentations are susceptible to lead to cold fission and which fragment-charge divisions are the most favored in each isobaric mass chain. Being based merely on energy arguments, the model cannot aim at predicting fragment yields in cold fission. However, the tip model proposed appears well suited to delineate the phase space where cold fission phenomena may come into sight. (orig.)

Effects of fungicides and bactericides on orchid seed germination and shoot tip cultures in vitro

OpenAIRE

Brown, DM; Groom, CL; Cvitanik, M; Brown, M; Cooper, JL; Arditti, J

1981-01-01

Amphotericin B, benomyl, gentamycin, nystatin, quintozene penicillin G, sodium omadine, and vancomycin singly and in several combinations have no deleterious effects on the germination of orchid seeds, but inhibit the growth in vitro of shoot tip explants. © 1981 Martinus Nijhoff/Dr W. Junk Publishers.

Fabrication and Study of Micro Monolithic Tungsten Ball Tips for Micro/Nano-CMM Probes

Directory of Open Access Journals (Sweden)

Ruijun Li

2018-03-01

Full Text Available Micro ball tips with high precision, small diameter, and high stiffness stems are required to measure microstructures with high aspect ratio. Existing ball tips cannot meet such demands because of their weak qualities. This study used an arc-discharge melting method to fabricate a micro monolithic tungsten ball tip on a tungsten stylus. The principles of arc discharge and surface tension phenomenon were introduced. The experimental setup was designed and established. Appropriate process parameters, such as impulse voltage, electro discharge time, and discharge gap were determined. Experimental results showed that a ball tip of approximately 60 µm in diameter with less than 0.6 µm roundness error and 0.6 µm center offset could be realized on a 100 µm-diameter tungsten wire. The fabricated micro ball tip was installed on a homemade probe, touched by high-precision gauge blocks in different directions. A repeatability of 41 nm (K = 2 was obtained. Several interesting phenomena in the ball-forming process were also discussed. The proposed method could be used to fabricate a monolithic probe ball tip, which is necessary for measuring microstructures.

Refined tip preparation by electrochemical etching and ultrahigh vacuum treatment to obtain atomically sharp tips for scanning tunneling microscope and atomic force microscope.

Science.gov (United States)

Hagedorn, Till; El Ouali, Mehdi; Paul, William; Oliver, David; Miyahara, Yoichi; Grütter, Peter

2011-11-01

A modification of the common electrochemical etching setup is presented. The described method reproducibly yields sharp tungsten tips for usage in the scanning tunneling microscope and tuning fork atomic force microscope. In situ treatment under ultrahigh vacuum (p ≤10(-10) mbar) conditions for cleaning and fine sharpening with minimal blunting is described. The structure of the microscopic apex of these tips is atomically resolved with field ion microscopy and cross checked with field emission. © 2011 American Institute of Physics

Explaining the Effectiveness of the Contrast Culture Method for Managing Interpersonal Interactions across Cultures

Science.gov (United States)

Hiratsuka, Hiroyoshi; Suzuki, Hanako; Pusina, Alexis

2016-01-01

One of the current challenges in the field of intercultural education comes from the limited availability of training efficacy studies. The present study focused on explaining the effectiveness of the Contrast Culture Method (CCM) as an intercultural education method for managing interpersonal interactions across cultures between graduate…

Early warning of climate tipping points

Science.gov (United States)

Lenton, Timothy M.

2011-07-01

A climate 'tipping point' occurs when a small change in forcing triggers a strongly nonlinear response in the internal dynamics of part of the climate system, qualitatively changing its future state. Human-induced climate change could push several large-scale 'tipping elements' past a tipping point. Candidates include irreversible melt of the Greenland ice sheet, dieback of the Amazon rainforest and shift of the West African monsoon. Recent assessments give an increased probability of future tipping events, and the corresponding impacts are estimated to be large, making them significant risks. Recent work shows that early warning of an approaching climate tipping point is possible in principle, and could have considerable value in reducing the risk that they pose.

AFM tip-sample convolution effects for cylinder protrusions

Science.gov (United States)

Shen, Jian; Zhang, Dan; Zhang, Fei-Hu; Gan, Yang

2017-11-01

A thorough understanding about the AFM tip geometry dependent artifacts and tip-sample convolution effect is essential for reliable AFM topographic characterization and dimensional metrology. Using rigid sapphire cylinder protrusions (diameter: 2.25 μm, height: 575 nm) as the model system, a systematic and quantitative study about the imaging artifacts of four types of tips-two different pyramidal tips, one tetrahedral tip and one super sharp whisker tip-is carried out through comparing tip geometry dependent variations in AFM topography of cylinders and constructing the rigid tip-cylinder convolution models. We found that the imaging artifacts and the tip-sample convolution effect are critically related to the actual inclination of the working cantilever, the tip geometry, and the obstructive contacts between the working tip's planes/edges and the cylinder. Artifact-free images can only be obtained provided that all planes and edges of the working tip are steeper than the cylinder sidewalls. The findings reported here will contribute to reliable AFM characterization of surface features of micron or hundreds of nanometers in height that are frequently met in semiconductor, biology and materials fields.

Improved flare tip design

Energy Technology Data Exchange (ETDEWEB)

Gogolek, P. [Natural Resources Canada, Ottawa, ON (Canada). CANMET Energy Technology Centre

2004-07-01

This paper discusses the testing procedures and development of an improved flare tip design. Design objectives included performance equal to or better than utility flares at low wind speed; conversion efficiency; fuel slip; smoking; significant improvement at high wind speed; and no increase in trace emissions. A description of the testing facility of the flare tip was provided, with reference to the fact that the facility allowed for realistic near full scale gas flares in a single-pass flare test facility. Other details of the facility included: an adjustable ceiling; high capacity variable speed fan; sampling ports along working section in stack; windows along working section; and air cooled walls, floor, and ceiling. The fuels used in the flare tip included natural gas, propane, gasoline and inert gases. Details of wind speed, appurtenances and turbulence generating grids were presented, with reference to continuous gas emission measurements. A list of design constraints was provided. Flare performance included wind speed, turbulence and fuel composition. A chart of conversion inefficiencies with a correlation of wind speed and turbulence, fuel flow and pipe size was also presented. Several new tip designs were fabricated for testing, with screening tests for comparison to basic pipe and ranking designs. Significant improvements were found in one of the new designs, including results with 30 per cent propane in fuel. Emissions reduction from 10 to 35 per cent were noted. It was concluded that future work should focus on evaluating improved tip for stability at low wind speeds. Fuel slips are the primary source of emissions, and it was recommended that further research is necessary to improve existing flare tips. tabs, figs.

Cytokinesis-block micronucleus method in micro-blood cultures

International Nuclear Information System (INIS)

Liu Jinwen; Wang Lianzhi; Yang Cangzhen; Yao Yanyu

1991-01-01

This paper reports the cytokinesis-block micronucleus method in micro-blood cultures. The observations on detection induced micronuclei of different doses of 60 Co γ-rays irradiation and spontaneous micronucleus of different ages were performed with CB method in comporison with conventional micronucleus (CM) method. The results showed that with direct peripheral micro-blood cultures the cytoknesis-block micronuclei is also obtained. Using CB method, the micronuclei fequency of different ages was linear relationship, Y = 1.62 + 0.74 D, the spontaneous micronuclei frequency of different ages was 4.14%, the induced micronuclei also was a linear relationship, Y = 6.01 + 0.692 D. Using CM method, it showed that the induced micronuclei was a linear relationship, Y = 0.486 D - 1.968, but there is no significant difference between the micronuclei frequency of different ages. Comparison with CM and direct blood smear methods confirmed that the cytokinesis-block method of micro-blood cultures is more sensitive and precise

Tip-tilt disturbance model identification based on non-linear least squares fitting for Linear Quadratic Gaussian control

Science.gov (United States)

Yang, Kangjian; Yang, Ping; Wang, Shuai; Dong, Lizhi; Xu, Bing

2018-05-01

We propose a method to identify tip-tilt disturbance model for Linear Quadratic Gaussian control. This identification method based on Levenberg-Marquardt method conducts with a little prior information and no auxiliary system and it is convenient to identify the tip-tilt disturbance model on-line for real-time control. This identification method makes it easy that Linear Quadratic Gaussian control runs efficiently in different adaptive optics systems for vibration mitigation. The validity of the Linear Quadratic Gaussian control associated with this tip-tilt disturbance model identification method is verified by experimental data, which is conducted in replay mode by simulation.

Reconstruction of the Tip-Surface Interaction Potential by Analysis of the Brownian Motion of an Atomic Force Microscope Tip

NARCIS (Netherlands)

Willemsen, O.H.; Kuipers, L.; van der Werf, Kees; de Grooth, B.G.; Greve, Jan

2000-01-01

The thermal movement of an atomic force microscope (AFM) tip is used to reconstruct the tip-surface interaction potential. If a tip is brought into the vicinity of a surface, its movement is governed by the sum of the harmonic cantilever potential and the tip-surface interaction potential. By

Turbulent Heat Transfer of a Finned Plate in a Duct as Tip Clearance Changes

Energy Technology Data Exchange (ETDEWEB)

Park, Hae-Kyun; Chung, Bum-Jin [Kyung Hee University, Yongin (Korea, Republic of)

2015-05-15

Fins are employed to enhance the cooling performance of a system. There are a number of studies relevant to geometry of fins. Meanwhile, the studies relevant to tip clearance, have not performed enough, which is the distance between the tips of the fins and the wall. We investigated the optimal tip clearance, which maximizes the heat transfers by experimental and numerical analyses with wider range of Re{sub Dh} than the previous studies. Turbulent heat transfers of a finned plate were measured. For an extended range of tip clearance and Re{sub Dh} than other studies. A joint experimental and numerical analyses was performed to measure heat transfers. Mass transfer experiments using electroplating system was used and FLUENT 6.3.26 was used for the calculation. For the narrow tip clearances below 5 mm, were investigated by numerical method only. The bypass flow to the tip clearance region contributes to heat transfer area at the tip clearance region and does not contributes that of the fin region. Thus, the optimal tip clearance was founded and it exists vicinity of 0.2 mm.

Tip-induced nanoreactor for silicate

Science.gov (United States)

Gao, Ming; Ma, Liran; Liang, Yong; Gao, Yuan; Luo, Jianbin

2015-09-01

Nanoscale scientific issues have attracted an increasing amount of research interest due to their specific size-effect and novel structure-property. From macro to nano, materials present some unique chemical reactivity that bulk materials do not own. Here we introduce a facile method to generate silicate with nanoscale control based on the establishment of a confined space between a meso/nanoscale tungsten tip and a smooth silica/silicon substrate. During the process, local water-like droplets deposition can be obviously observed in the confinement between the Si/SiO2 surfaces and the KOH-modified tungsten tip. By the combination of in-situ optical microscopy and Raman spectroscopy, we were able to take a deep insight of both the product composition and the underlying mechanism of such phenomena. It was indicated that such nanoreactor for silicate could be quite efficient as a result of the local capillarity and electric field effect, with implications at both nano and meso scales.

A study on tip leakage vortex dynamics and cavitation in axial-flow pump

Energy Technology Data Exchange (ETDEWEB)

Shi, Lei; Zhang, Desheng; Jin, Yongxin; Shi, Weidong [Research Center of Fluid Machinery Engineering and Technology, Jiangsu University, Zhenjiang 212013 (China); Esch, B P M van, E-mail: zds@ujs.edu.cn [Department of Mechanical Engineering, Eindhoven University of Technology, Eindhoven 5600 MB (Netherlands)

2017-06-15

The tip leakage flows and related cavitation in the tip region of an axial-flow pump were investigated in detail using the numerical and experimental methods. The numerical results of the pump model performance were in good agreement with experimental data. The flow structures in the tip clearance were clarified clearly with detailed data involving the axial velocity and turbulent kinetic energy. When depicting the feature of vortex core, the advanced vortex identification method λ {sub 2}-criterion was used. Simultaneously, the minimum tension criterion was also applied to predict the cavitation inception for different flow rates and it is consistent with the distributions of vorticity and pressure in the vortex core. The roll-up process of TLV is highly three-dimensional and the entrainment would follow different paths. Then, both the numerical and experimental approaches show the cavitation patterns for different cavitation conditions, and it also finds that slight cavitation would promote the development of tip leakage vortex (TLV) while the TLV seems to be eliminated for a low cavitation number, especially before a specific location of blade tip due to the blade loading change induced by cavitation possibly. (paper)

Simultaneous AFM and fluorescence imaging: A method for aligning an AFM-tip with an excitation beam using a 2D galvanometer

Science.gov (United States)

Moores, A. N.; Cadby, A. J.

2018-02-01

Correlative fluorescence and atomic force microscopy (AFM) imaging is a highly attractive technique for use in biological imaging, enabling force and mechanical measurements of particular structures whose locations are known due to the specificity of fluorescence imaging. The ability to perform these two measurements simultaneously (rather than consecutively with post-processing correlation) is highly valuable because it would allow the mechanical properties of a structure to be tracked over time as changes in the sample occur. We present an instrument which allows simultaneous AFM and fluorescence imaging by aligning an incident fluorescence excitation beam with an AFM-tip. Alignment was performed by calibrating a 2D galvanometer present in the excitation beam path and using it to reposition the incident beam. Two programs were developed (one manual and one automated) which correlate sample features between the AFM and fluorescence images, calculating the distance required to translate the incident beam towards the AFM-tip. Using this method, we were able to obtain beam-tip alignment (and therefore field-of-view alignment) from an offset of >15 μm to within one micron in two iterations of the program. With the program running alongside data acquisition for real-time feedback between AFM and optical images, this offset was maintained over a time period of several hours. Not only does this eliminate the need to image large areas with both techniques to ensure that fields-of-view overlap, but it also raises the possibility of using this instrument for tip-enhanced fluorescence applications, a technique in which super-resolution images have previously been achieved.

An Optical Fiber Bundle Sensor for Tip Clearance and Tip Timing Measurements in a Turbine Rig

Directory of Open Access Journals (Sweden)

María Asunción Illarramendi

2013-06-01

Full Text Available When it comes to measuring blade-tip clearance or blade-tip timing in turbines, reflective intensity-modulated optical fiber sensors overcome several traditional limitations of capacitive, inductive or discharging probe sensors. This paper presents the signals and results corresponding to the third stage of a multistage turbine rig, obtained from a transonic wind-tunnel test. The probe is based on a trifurcated bundle of optical fibers that is mounted on the turbine casing. To eliminate the influence of light source intensity variations and blade surface reflectivity, the sensing principle is based on the quotient of the voltages obtained from the two receiving bundle legs. A discrepancy lower than 3% with respect to a commercial sensor was observed in tip clearance measurements. Regarding tip timing measurements, the travel wave spectrum was obtained, which provides the average vibration amplitude for all blades at a particular nodal diameter. With this approach, both blade-tip timing and tip clearance measurements can be carried out simultaneously. The results obtained on the test turbine rig demonstrate the suitability and reliability of the type of sensor used, and suggest the possibility of performing these measurements in real turbines under real working conditions.

Tips for Living with Scleroderma

Science.gov (United States)

... Patients Tips for Living Tips for Living with Scleroderma Ways to help manage your symptoms The Scleroderma ... help find improved therapies and a cure for scleroderma! Your gift today will be matched to have ...

Control of droplet morphology for inkjet-printed TIPS-pentacene transistors

Science.gov (United States)

Lee, Myung Won; Ryu, Gi Seong; Lee, Young Uk; Pearson, Christopher; Petty, Michael C.; Song, Chung Kun

2012-01-01

We report on methods to control the morphology of droplets of 6,13-bis(triisopropyl-silylethynyl) pentacene (TIPS-PEN), which are then used in the fabrication of organic thin film transistors (OTFTs). The grain size and distribution of the TIPS-PEN were found to depend on the temperature of the droplets during drying. The performance of the OTFTs could be improved by heating the substrate and also by changing the relative positions of the inkjet-printed droplets. In our experiments, the optimum substrate temperature was 46 °C in air. Transistors with the TIPS-PEN grain boundaries parallel to the current flow between the source and drain electrodes exhibited charge carrier mobilities of 0.44 ± 0.08 cm2/V s.

Transjugular Intrahepatic Portosystemic Shunt (TIPS)

Medline Plus

Full Text Available ... or bypass, without the risks that accompany open surgery. TIPS is a minimally invasive procedure that typically has a shorter recovery time than surgery. Your TIPS should have less of an effect ...

Probing the probe: AFM tip-profiling via nanotemplates to determine Hamaker constants from phase–distance curves

International Nuclear Information System (INIS)

Rodriguez, Raul D.; Lacaze, Emmanuelle; Jupille, Jacques

2012-01-01

A method to determine the van der Waals forces from phase–distance curves recorded by atomic force microscopy (AFM) in tapping mode is presented. The relationship between the phase shift and the tip–sample distance is expressed as a function of the product of the Hamaker constant by tip radius. Silica-covered silicon tips are used to probe silica-covered silicon substrate in dry conditions to avoid capillary effects. Tips being assumed spherical, radii are determined in situ by averaging profiles recorded in different directions on hematite nanocrystals acting as nanotemplates, thus accounting for tip anisotropy. Through a series of reproducible measurements performed with tips of various radii (including the in-situ characterization of a damaged tip), a value of (6.3±0.4)×10 −20 J is found for the Hamaker constant of interacting silica surfaces in air, in good agreement with tabulated data. The results demonstrate that the onset of the tip–surface interaction is dominated by the van der Waals forces and that the total force can be modeled in the framework of the harmonic approximation. Based on the tip radius and the Hamaker constant associated to the tip–substrate system, the model is quite flexible. Once the Hamaker constant is known, a direct estimate of the tip size can be achieved whereas when the tip size is known, a quantitative evaluation of the van der Waals force becomes possible on different substrates with a spatial resolution at the nanoscale. -- Highlights: ► Van der Waal forces in tapping mode atomic force microscopy. ► Harmonic approximation model of phase–distance curves probed by simulations. ► Silica tips and surfaces as a model case. ► Tip geometry determined in situ by nanoparticles as nanotemplates. ► Method to derive the Hamaker constant for any tip/surface system.

Structure and dynamics of TIP3P, TIP4P, and TIP5P water near smooth and atomistic walls of different hydroaffinity

International Nuclear Information System (INIS)

Harrach, Michael F.; Drossel, Barbara

2014-01-01

We perform molecular dynamics simulations to observe the structure and dynamics of water using different water models (TIP3P, TIP4P, TIP5P) at ambient conditions, constrained by planar walls, which are either modeled by smooth potentials or regular atomic lattices, imitating the honeycomb-structure of graphene. We implement walls of different hydroaffinity, different lattice constant, and different types of interaction with the water molecules. We find that in the hydrophobic regime the smooth wall generally represents a good abstraction of the atomically rough walls, while in the hydrophilic regime there are noticeable differences in structure and dynamics between all stages of wall roughness. For a small lattice constant however the smooth and the atomically rough wall still share a number of structural and dynamical similarities. Out of the three water models, TIP5P water shows the largest degree of tetrahedral ordering and is often the one that is least perturbed by the presence of the wall

Rotating coherent flow structures as a source for narrowband tip clearance noise from axial fans

Science.gov (United States)

Zhu, Tao; Lallier-Daniels, Dominic; Sanjosé, Marlène; Moreau, Stéphane; Carolus, Thomas

2018-03-01

Noise from axial fans typically increases significantly as the tip clearance is increased. In addition to the broadband tip clearance noise at the design flow rate, narrowband humps also associated with the tip flow are observed in the far-field acoustic spectra at lower flow rate. In this study, both experimental and numerical methods are used to shed more light on the noise generation mechanism of this narrowband tip clearance noise and provide a unified description of this source. Unsteady aeroacoustic predictions with the Lattice-Boltzmann Method (LBM) are successfully compared with experiment. Such a validation allows using LBM data to conduct a detailed modal analysis of the pressure field for detecting rotating coherent flow structures which might be considered as noise sources. As previously found in ring fans the narrowband humps in the far-field noise spectra are found to be related to the tip clearance noise that is generated by an interaction of coherent flow structures present in the tip region with the leading edge of the impeller blades. The visualization of the coherent structures shows that they are indeed part of the unsteady tip clearance vortex structures. They are hidden in a complex, spatially and temporally inhomogeneous flow field, but can be recovered by means of appropriate filtering techniques. Their pressure trace corresponds to the so-called rotational instability identified in previous turbomachinery studies, which brings a unified picture of this tip-noise phenomenon for the first time.

RANS computations of tip vortex cavitation

Science.gov (United States)

Decaix, Jean; Balarac, Guillaume; Dreyer, Matthieu; Farhat, Mohamed; Münch, Cécile

2015-12-01

The present study is related to the development of the tip vortex cavitation in Kaplan turbines. The investigation is carried out on a simplified test case consisting of a NACA0009 blade with a gap between the blade tip and the side wall. Computations with and without cavitation are performed using a R ANS modelling and a transport equation for the liquid volume fraction. Compared with experimental data, the R ANS computations turn out to be able to capture accurately the development of the tip vortex. The simulations have also highlighted the influence of cavitation on the tip vortex trajectory.

Tip displacement variance of manipulator to simultaneous horizontal and vertical stochastic base excitations

International Nuclear Information System (INIS)

Rahi, A.; Bahrami, M.; Rastegar, J.

2002-01-01

The tip displacement variance of an articulated robotic manipulator to simultaneous horizontal and vertical stochastic base excitation is studied. The dynamic equations for an n-links manipulator subjected to both horizontal and vertical stochastic excitations are derived by Lagrangian method and decoupled for small displacement of joints. The dynamic response covariance of the manipulator links is computed in the coordinate frame attached to the base and then the principal variance of tip displacement is determined. Finally, simulation for a two-link planner robotic manipulator under base excitation is developed. Then sensitivity of the principal variance of tip displacement and tip velocity to manipulator configuration, damping, excitation parameters and manipulator links length are investigated

Transjugular Intrahepatic Portosystemic Shunt (TIPS)

Medline Plus

Full Text Available ... pressure. top of page How does the procedure work? A TIPS reroutes blood flow in the liver ... filtered out by the liver. The TIPS may cause too much of these substances to bypass the ...

Transjugular Intrahepatic Portosystemic Shunt (TIPS)

Medline Plus

Full Text Available ... then placed in this tunnel to keep the pathway open. Patients who typically need a TIPS have ... and stomach. A TIPS procedure involves creating a pathway through the liver that connects the portal vein ( ...

Transjugular Intrahepatic Portosystemic Shunt (TIPS)

Medline Plus

Full Text Available ... and/or hydrothorax (in the chest). Budd-Chiari syndrome , a blockage in one or more veins that ... intentionally to solve the problem. Although extremely rare, children may also require a TIPS procedure. TIPS in ...

Transjugular Intrahepatic Portosystemic Shunt (TIPS)

Medline Plus

Full Text Available ... the esophagus and stomach. A TIPS procedure involves creating a pathway through the liver that connects the ... diseases. This can result in significant challenges in creating the TIPS. top of page Additional Information and ...

Transjugular Intrahepatic Portosystemic Shunt (TIPS)

Medline Plus

Full Text Available ... TIPS. top of page What are some common uses of the procedure? A TIPS is used to ... community, you can search the ACR-accredited facilities database . This website does not provide cost information. The ...

Transjugular Intrahepatic Portosystemic Shunt (TIPS)

Medline Plus

Full Text Available ... pressure. top of page How does the procedure work? A TIPS reroutes blood flow in the liver ... recovery time than surgery. Your TIPS should have less of an effect than open surgical bypass on ...

A method for culturing human hair follicle cells.

Science.gov (United States)

Weterings, P J; Vermorken, A J; Bloemendal, H

1981-01-01

For the first time a method for culturing human hair follicle cells is described. The bovine eye lens capsule, a basement membrane-like structure, is used as the substrate for the cultures. In a culture medium supplemented with hydrocortisone and insulin about 70% of the original follicles will form growing colonies of diploid keratinocytes.

Comparison of PCR method with the culture method for identification of gonococci from endocervical swabs

Directory of Open Access Journals (Sweden)

Alam A

2002-01-01

Full Text Available Gonococcal infection remains still a major cause of morbidity among sexually active individuals. Diagnosis of the infection in a female case is more difficult than that in a male. This was a prospective study among 269 female commercial sex workers (CSWs to screen them for gonococcal infection, comparing the rapid method of identification of gonococci by polymerase chain reaction (PCR with the selective culture method. A total of 92 (34.2% CSWs were identified positive for Neisseria gonorrhoeae by combination of the two methods. The PCR method identified 87 of the specimens to harbour cppB gene of N. gonorrhoeae, whereas culture method identified 83 specimens showing colonies of gonococci. Taking into consideration of the total positive cases (92, the PCR method showed a sensitivity of 94.57%, whereas sensitivity of culture method was 90.22%. The selective culture method appears to be the most applicable in the identification of gonococci from clinical specimens, particularly in the less resourceful countries like Bangladesh.

Comparison of Standard Culture-Based Method to Culture-Independent Method for Evaluation of Hygiene Effects on the Hand Microbiome

Directory of Open Access Journals (Sweden)

C. Zapka

2017-03-01

Full Text Available Hands play a critical role in the transmission of microbiota on one’s own body, between individuals, and on environmental surfaces. Effectively measuring the composition of the hand microbiome is important to hand hygiene science, which has implications for human health. Hand hygiene products are evaluated using standard culture-based methods, but standard test methods for culture-independent microbiome characterization are lacking. We sampled the hands of 50 participants using swab-based and glove-based methods prior to and following four hand hygiene treatments (using a nonantimicrobial hand wash, alcohol-based hand sanitizer [ABHS], a 70% ethanol solution, or tap water. We compared results among culture plate counts, 16S rRNA gene sequencing of DNA extracted directly from hands, and sequencing of DNA extracted from culture plates. Glove-based sampling yielded higher numbers of unique operational taxonomic units (OTUs but had less diversity in bacterial community composition than swab-based sampling. We detected treatment-induced changes in diversity only by using swab-based samples (P < 0.001; we were unable to detect changes with glove-based samples. Bacterial cell counts significantly decreased with use of the ABHS (P < 0.05 and ethanol control (P < 0.05. Skin hydration at baseline correlated with bacterial abundances, bacterial community composition, pH, and redness across subjects. The importance of the method choice was substantial. These findings are important to ensure improvement of hand hygiene industry methods and for future hand microbiome studies. On the basis of our results and previously published studies, we propose recommendations for best practices in hand microbiome research.

Superconducting phase transition in STM tips

Energy Technology Data Exchange (ETDEWEB)

Eltschka, Matthias; Jaeck, Berthold; Assig, Maximilian; Etzkorn, Markus; Ast, Christian R. [Max Planck Institute for Solid State Research, Stuttgart (Germany); Kern, Klaus [Max Planck Institute for Solid State Research, Stuttgart (Germany); Ecole Polytechnique Federale de Lausanne (Switzerland)

2015-07-01

The superconducting properties of systems with dimensions comparable to the London penetration depth considerably differ from macroscopic systems. We have studied the superconducting phase transition of vanadium STM tips in external magnetic fields. Employing Maki's theory we extract the superconducting parameters such as the gap or the Zeeman splitting from differential conductance spectra. While the Zeeman splitting follows the theoretical description of a system with s=1/2 and g=2, the superconducting gaps as well as the critical fields depend on the specific tip. For a better understanding of the experimental results, we solve a one dimensional Usadel equation modeling the superconducting tip as a cone with the opening angle α in an external magnetic field. We find that only a small region at the apex of the tip is superconducting in high magnetic fields and that the order of the phase transition is directly determined by α. Further, the spectral broadening increases with α indicating an intrinsic broadening mechanism due to the conical shape of the tip. Comparing these calculations to our experimental results reveals the order of the superconducting phase transition of the STM tips.

Electro-optic detection of subwavelength terahertz spot sizes in the near field of a metal tip

NARCIS (Netherlands)

Van der Valk, N.C.J.; Planken, P.C.M.

2002-01-01

We report on a method to obtain a subwavelength resolution in terahertz time-domain imaging. In our method, a sharp copper tip is used to locally distort and concentrate the THz electric field. The distorted electric field, present mainly in the near field of the tip, is electro-optically measured

Radiofrequency Wire Recanalization of Chronically Thrombosed TIPS

Energy Technology Data Exchange (ETDEWEB)

Majdalany, Bill S., E-mail: bmajdala@med.umich.edu [University of Michigan Health System, Division of Interventional Radiology, Department of Radiology (United States); Elliott, Eric D., E-mail: eric.elliott@osumc.edu [The Ohio State University Wexner Medical Center, Division of Interventional Radiology, Department of Radiology (United States); Michaels, Anthony J., E-mail: Anthony.michaels@osumc.edu; Hanje, A. James, E-mail: James.Hanje@osumc.edu [The Ohio State University Wexner Medical Center, Division of Gastroenterology and Hepatology, Department of Medicine (United States); Saad, Wael E. A., E-mail: wsaad@med.umich.edu [University of Michigan Health System, Division of Interventional Radiology, Department of Radiology (United States)

2016-07-15

Radiofrequency (RF) guide wires have been applied to cardiac interventions, recanalization of central venous thromboses, and to cross biliary occlusions. Herein, the use of a RF wire technique to revise chronically occluded transjugular intrahepatic portosystemic shunts (TIPS) is described. In both cases, conventional TIPS revision techniques failed to revise the chronically thrombosed TIPS. RF wire recanalization was successfully performed through each of the chronically thrombosed TIPS, demonstrating initial safety and feasibility in this application.

Tip Clearance Control Using Plasma Actuators

Science.gov (United States)

2007-03-01

Clearance Control Using Plasma Actuators 4 posed by Denton (1993). A number of investigators have used partial shrouds, or " winglet " designs to...SDBD actuator Plasma enhanced aerodynamics has been demonstrated in a range of applications involving sepa- ration control, lift enhancement, drag... aerodynamic benefits of a squealer tip geometry. Specifically, the squealer tip is known to reduce the discharge coefficient of the tip gap, thereby

Tips for Good Electronic Presentations.

Science.gov (United States)

Strasser, Dennis

1996-01-01

Describes library uses of presentation graphics software and offers tips for creating electronic presentations. Tips include: audience retention; visual aid options; software package options; presentation planning; presentation showing; and use of text, colors, and graphics. Sidebars note common presentation errors and popular presentation…

The extended wedge method: atomic force microscope friction calibration for improved tolerance to instrument misalignments, tip offset, and blunt probes.

Science.gov (United States)

Khare, H S; Burris, D L

2013-05-01

One of the major challenges in understanding and controlling friction is the difficulty in bridging the length and time scales of macroscale contacts and those of the single asperity interactions they comprise. While the atomic force microscope (AFM) offers a unique ability to probe tribological surfaces in a wear-free single-asperity contact, instrument calibration challenges have limited the usefulness of this technique for quantitative nanotribological studies. A number of lateral force calibration techniques have been proposed and used, but none has gained universal acceptance due to practical considerations, configuration limitations, or sensitivities to unknowable error sources. This paper describes a simple extension of the classic wedge method of AFM lateral force calibration which: (1) allows simultaneous calibration and measurement on any substrate, thus eliminating prior tip damage and confounding effects of instrument setup adjustments; (2) is insensitive to adhesion, PSD cross-talk, transducer/piezo-tube axis misalignment, and shear-center offset; (3) is applicable to integrated tips and colloidal probes; and (4) is generally applicable to any reciprocating friction coefficient measurement. The method was applied to AFM measurements of polished carbon (99.999% graphite) and single crystal MoS2 to demonstrate the technique. Carbon and single crystal MoS2 had friction coefficients of μ = 0.20 ± 0.04 and μ = 0.006 ± 0.001, respectively, against an integrated Si probe. Against a glass colloidal sphere, MoS2 had a friction coefficient of μ = 0.005 ± 0.001. Generally, the measurement uncertainties ranged from 10%-20% and were driven by the effect of actual frictional variation on the calibration rather than calibration error itself (i.e., due to misalignment, tip-offset, or probe radius).

A hanging drop culture method to study terminal erythroid differentiation.

Science.gov (United States)

Gutiérrez, Laura; Lindeboom, Fokke; Ferreira, Rita; Drissen, Roy; Grosveld, Frank; Whyatt, David; Philipsen, Sjaak

2005-10-01

To design a culture method allowing the quantitative and qualitative analysis of terminal erythroid differentiation. Primary erythroid progenitors derived either from mouse tissues or from human umbilical cord blood were differentiated using hanging drop cultures and compared to methylcellulose cultures. Cultured cells were analyzed by FACS to assess differentiation. We describe a practical culture method by adapting the previously described hanging drop culture system to conditions allowing terminal differentiation of primary erythroid progenitors. Using minimal volumes of media and small numbers of cells, we obtained quantitative terminal erythroid differentiation within two days of culture in the case of murine cells and 4 days in the case of human cells. The established methods for ex vivo culture of primary erythroid progenitors, such as methylcellulose-based burst-forming unit-erythroid (BFU-E) and colony-forming unit-erythroid (CFU-E) assays, allow the detection of committed erythroid progenitors but are of limited value to study terminal erythroid differentiation. We show that the application of hanging drop cultures is a practical alternative that, in combination with clonogenic assays, enables a comprehensive assessment of the behavior of primary erythroid cells ex vivo in the context of genetic and drug-induced perturbations.

A simple method to prevent hard X-ray-induced preheating effects inside the cone tip in indirect-drive fast ignition implosions

International Nuclear Information System (INIS)

Liu, Dongxiao; Shan, Lianqiang; Zhou, Weimin; Wu, Yuchi; Zhu, Bin; Zhang, Feng; Bi, Bi; Zhang, Bo; Zhang, Zhimeng; Shui, Min; He, Yingling; Gu, Yuqiu; Zhang, Baohan; Peng, Xiaoshi; Xu, Tao; Wang, Feng; Yang, Zhiwen; Chen, Tao; Chen, Li; Chen, Ming

2016-01-01

During fast-ignition implosions, preheating of inside the cone tip caused by hard X-rays can strongly affect the generation and transport of hot electrons in the cone. Although indirect-drive implosions have a higher implosion symmetry, they cause stronger preheating effects than direct-drive implosions. To control the preheating of the cone tip, we propose the use of indirect-drive fast-ignition targets with thicker tips. Experiments carried out at the ShenGuang-III prototype laser facility confirmed that thicker tips are effective for controlling preheating. Moreover, these results were consistent with those of 1D radiation hydrodynamic simulations.

A simple method to prevent hard X-ray-induced preheating effects inside the cone tip in indirect-drive fast ignition implosions

Energy Technology Data Exchange (ETDEWEB)

Liu, Dongxiao; Shan, Lianqiang; Zhou, Weimin; Wu, Yuchi; Zhu, Bin; Zhang, Feng; Bi, Bi; Zhang, Bo; Zhang, Zhimeng; Shui, Min; He, Yingling; Gu, Yuqiu, E-mail: yqgu@caep.cn; Zhang, Baohan [Science and Technology on Plasma Physics Laboratory, China Academy of Engineering Physics, Mianyang 621900 (China); Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); Peng, Xiaoshi; Xu, Tao; Wang, Feng; Yang, Zhiwen; Chen, Tao; Chen, Li; Chen, Ming [Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); and others

2016-06-15

During fast-ignition implosions, preheating of inside the cone tip caused by hard X-rays can strongly affect the generation and transport of hot electrons in the cone. Although indirect-drive implosions have a higher implosion symmetry, they cause stronger preheating effects than direct-drive implosions. To control the preheating of the cone tip, we propose the use of indirect-drive fast-ignition targets with thicker tips. Experiments carried out at the ShenGuang-III prototype laser facility confirmed that thicker tips are effective for controlling preheating. Moreover, these results were consistent with those of 1D radiation hydrodynamic simulations.

Nanofluidic channels of arbitrary shapes fabricated by tip-based nanofabrication

International Nuclear Information System (INIS)

Hu, Huan; Cunningham, Brian T; King, William P; Zhuo, Yue; Oruc, Muhammed E

2014-01-01

Nanofluidic channels have promising applications in biomolecule manipulation and sensing. While several different methods of fabrication have been demonstrated for nanofluidic channels, a rapid, low-cost fabrication method that can fabricate arbitrary shapes of nanofluidic channels is still in demand. Here, we report a tip-based nanofabrication (TBN) method for fabricating nanofluidic channels using a heated atomic force microscopy (AFM) tip. The heated AFM tip deposits polymer nanowires where needed to serve as etch mask to fabricate silicon molds through one step of etching. PDMS nanofluidic channels are easily fabricated through replicate molding using the silicon molds. Various shapes of nanofluidic channels with either straight or curvilinear features are demonstrated. The width of the nanofluidic channels is 500 nm, and is determined by the deposited polymer nanowire width. The height of the channel is 400 nm determined by the silicon etching time. Ion conductance measurement on one single curvy shaped nanofluidic channel exhibits the typical ion conductance saturation phenomenon as the ion concentration decreases. Moreover, fluorescence imaging of fluid flowing through a fabricated nanofluidic channel demonstrates the channel integrity. This TBN process is seamlessly compatible with existing nanofabrication processes and can be used to achieve new types of nanofluidic devices. (paper)

Automated, simple, and efficient influenza RNA extraction from clinical respiratory swabs using TruTip and epMotion.

Science.gov (United States)

Griesemer, Sara B; Holmberg, Rebecca; Cooney, Christopher G; Thakore, Nitu; Gindlesperger, Alissa; Knickerbocker, Christopher; Chandler, Darrell P; St George, Kirsten

2013-09-01

Rapid, simple and efficient influenza RNA purification from clinical samples is essential for sensitive molecular detection of influenza infection. Automation of the TruTip extraction method can increase sample throughput while maintaining performance. To automate TruTip influenza RNA extraction using an Eppendorf epMotion robotic liquid handler, and to compare its performance to the bioMerieux easyMAG and Qiagen QIAcube instruments. Extraction efficacy and reproducibility of the automated TruTip/epMotion protocol was assessed from influenza-negative respiratory samples spiked with influenza A and B viruses. Clinical extraction performance from 170 influenza A and B-positive respiratory swabs was also evaluated and compared using influenza A and B real-time RT-PCR assays. TruTip/epMotion extraction efficacy was 100% in influenza virus-spiked samples with at least 745 influenza A and 370 influenza B input gene copies per extraction, and exhibited high reproducibility over four log10 concentrations of virus (extraction were also positive following TruTip extraction. Overall Ct value differences obtained between TruTip/epMotion and easyMAG/QIAcube clinical extracts ranged from 1.24 to 1.91. Pairwise comparisons of Ct values showed a high correlation of the TruTip/epMotion protocol to the other methods (R2>0.90). The automated TruTip/epMotion protocol is a simple and rapid extraction method that reproducibly purifies influenza RNA from respiratory swabs, with comparable efficacy and efficiency to both the easyMAG and QIAcube instruments. Copyright © 2013 Elsevier B.V. All rights reserved.

The Results of the Treatment of Osteogenesis Imperfecta with Corkscrew Tipped Telescopic Nail

Directory of Open Access Journals (Sweden)

Hüseyin Günay

2017-03-01

Full Text Available Aim: We aimed to evaluate the clinical and radiological results of an intramedullary fixation system used in surgeries for fractures and deformities of osteogenesis imperfecta where we applied a new design corkscrew tipped intramedullary nailing. Materials and Methods: Twenty extremities of 14 osteogenesis cases, who underwent surgery and to whom corkscrew tipped intramedullary treatment was applied, were retrospectively scanned. Ambulation, discrepancies in the lenght of extremities, deformities and joint mobility range were all noted before the operation. Postoperative union rates, complications and our experience regarding the nail were also evaluated. Results: Six tibia and 14 femurs were operated using corkscrew tipped telescopic nails. Two bones were operated due to non-union, while seven bones underwent surgery due to acute fractures and 11 bones due to deformities. All the bones were seen to have achieved the aimed union. No major complications were observed. Infection was present in two cases. Conclusion: Corkscrew tipped telescopic nail is a safe and effective method of fixation in patients with osteogenesis imperfecta.

A simple method for multiday imaging of slice cultures.

Science.gov (United States)

Seidl, Armin H; Rubel, Edwin W

2010-01-01

The organotypic slice culture (Stoppini et al. A simple method for organotypic cultures of nervous tissue. 1991;37:173-182) has become the method of choice to answer a variety of questions in neuroscience. For many experiments, however, it would be beneficial to image or manipulate a slice culture repeatedly, for example, over the course of many days. We prepared organotypic slice cultures of the auditory brainstem of P3 and P4 mice and kept them in vitro for up to 4 weeks. Single cells in the auditory brainstem were transfected with plasmids expressing fluorescent proteins by way of electroporation (Haas et al. Single-cell electroporation for gene transfer in vivo. 2001;29:583-591). The culture was then placed in a chamber perfused with oxygenated ACSF and the labeled cell imaged with an inverted wide-field microscope repeatedly for multiple days, recording several time-points per day, before returning the slice to the incubator. We describe a simple method to image a slice culture preparation during the course of multiple days and over many continuous hours, without noticeable damage to the tissue or photobleaching. Our method uses a simple, inexpensive custom-built insulator constructed around the microscope to maintain controlled temperature and uses a perfusion chamber as used for in vitro slice recordings. (c) 2009 Wiley-Liss, Inc.

Tip Effect of the Tapping Mode of Atomic Force Microscope in Viscous Fluid Environments.

Science.gov (United States)

Shih, Hua-Ju; Shih, Po-Jen

2015-07-28

Atomic force microscope with applicable types of operation in a liquid environment is widely used to scan the contours of biological specimens. The contact mode of operation allows a tip to touch a specimen directly but sometimes it damages the specimen; thus, a tapping mode of operation may replace the contact mode. The tapping mode triggers the cantilever of the microscope approximately at resonance frequencies, and so the tip periodically knocks the specimen. It is well known that the cantilever induces extra liquid pressure that leads to drift in the resonance frequency. Studies have noted that the heights of protein surfaces measured via the tapping mode of an atomic force microscope are ~25% smaller than those measured by other methods. This discrepancy may be attributable to the induced superficial hydrodynamic pressure, which is worth investigating. In this paper, we introduce a semi-analytical method to analyze the pressure distribution of various tip geometries. According to our analysis, the maximum hydrodynamic pressure on the specimen caused by a cone-shaped tip is ~0.5 Pa, which can, for example, pre-deform a cell by several nanometers in compression before the tip taps it. Moreover, the pressure calculated on the surface of the specimen is 20 times larger than the pressure without considering the tip effect; these results have not been motioned in other papers. Dominating factors, such as surface heights of protein surface, mechanical stiffness of protein increasing with loading velocity, and radius of tip affecting the local pressure of specimen, are also addressed in this study.

Molecular tips for scanning tunneling microscopy: intermolecular electron tunneling for single-molecule recognition and electronics.

Science.gov (United States)

Nishino, Tomoaki

2014-01-01

This paper reviews the development of molecular tips for scanning tunneling microscopy (STM). Molecular tips offer many advantages: first is their ability to perform chemically selective imaging because of chemical interactions between the sample and the molecular tip, thus improving a major drawback of conventional STM. Rational design of the molecular tip allows sophisticated chemical recognition; e.g., chiral recognition and selective visualization of atomic defects in carbon nanotubes. Another advantage is that they provide a unique method to quantify electron transfer between single molecules. Understanding such electron transfer is mandatory for the realization of molecular electronics.

Simple and convenient method for culturing anaerobic bacteria.

OpenAIRE

Behbehani, M J; Jordan, H V; Santoro, D L

1982-01-01

A simple and convenient method for culturing anaerobic bacteria is described. Cultures can be grown in commercially available flasks normally used for preparation of sterile external solutions. A special disposable rubber flask closure maintains anaerobic conditions in the flask after autoclaving. Growth of a variety of anaerobic oral bacteria was comparable to that obtained after anaerobic incubation of broth cultures in Brewer Anaerobic Jars.

Sound source location in cavitating tip vortices

International Nuclear Information System (INIS)

Higuchi, H.; Taghavi, R.; Arndt, R.E.A.

1985-01-01

Utilizing an array of three hydrophones, individual cavitation bursts in a tip vortex could be located. Theoretically, four hydrophones are necessary. Hence the data from three hydrophones are supplemented with photographic observation of the cavitating tip vortex. The cavitation sound sources are found to be localized to within one base chord length from the hydrofoil tip. This appears to correspond to the region of initial tip vortex roll-up. A more extensive study with a four sensor array is now in progress

Computerized automatic tip scanning operation

International Nuclear Information System (INIS)

Nishikawa, K.; Fukushima, T.; Nakai, H.; Yanagisawa, A.

1984-01-01

In BWR nuclear power stations the Traversing Incore Probe (TIP) system is one of the most important components in reactor monitoring and control. In previous TIP systems, however, operators have suffered from the complexity of operation and long operation time required. The system presented in this paper realizes the automatic operation of the TIP system by monitoring and driving it with a process computer. This system significantly reduces the burden on customer operators and improves plant efficiency by simplifying the operating procedure, augmenting the accuracy of the measured data, and shortening operating time. The process computer is one of the PODIA (Plant Operation by Displayed Information Automation) systems. This computer transfers control signals to the TIP control panel, which in turn drives equipment by microprocessor control. The process computer contains such components as the CRT/KB unit, the printer plotter, the hard copier, and the message typers required for efficient man-machine communications. Its operation and interface properties are described

Study of tip loss corrections using CFD rotor computations

DEFF Research Database (Denmark)

Shen, Wen Zhong; Zhu, Wei Jun; Sørensen, Jens Nørkær

2014-01-01

Tip loss correction is known to play an important role for engineering prediction of wind turbine performance. There are two different types of tip loss corrections: tip corrections on momentum theory and tip corrections on airfoil data. In this paper, we study the latter using detailed CFD...... computations for wind turbines with sharp tip. Using the technique of determination of angle of attack and the CFD results for a NordTank 500 kW rotor, airfoil data are extracted and a new tip loss function on airfoil data is derived. To validate, BEM computations with the new tip loss function are carried out...... and compared with CFD results for the NordTank 500 kW turbine and the NREL 5 MW turbine. Comparisons show that BEM with the new tip loss function can predict correctly the loading near the blade tip....

[TIPS

Science.gov (United States)

Brazzini, Augusto; Carrillo, Alvaro; Cantella, Raúl

1998-01-01

Esophageal hemorrage due to variceal bleeding in cirrhotic patients represents a serious problem for the physician in charge, especially in this country where liver transplants are inexistent; and also, it is a drama for the patient and its familly. We propose here the Transjugular Intrahepatic Portosystemic Shunt (TIPS). Twenty one patients were part of a study where 23 TIPS were placed, observing an immediate improval in 18 of them, a rebleeding in 2, within the first 24 and 48 hours. An embolization of the coronary veins was performed in the procedure in 15 patients, and a second intervention due to rebleeding in 2 of them. In the latter patients, the embolization of the coronary veins was rutinary.The survival of the patients has been outstanding.We conclude that this interventional procedure is a worldwide reality in the treatment of esophageal hemorrage by variceal bleeding due to portal hipertension, and it does not cut down the probability of liver transplant, unfortunately inexistent in our country. This procedure results in a low morbimortality with an adequate quality of life.

Aperiodicity Correction for Rotor Tip Vortex Measurements

Science.gov (United States)

Ramasamy, Manikandan; Paetzel, Ryan; Bhagwat, Mahendra J.

2011-01-01

The initial roll-up of a tip vortex trailing from a model-scale, hovering rotor was measured using particle image velocimetry. The unique feature of the measurements was that a microscope was attached to the camera to allow much higher spatial resolution than hitherto possible. This also posed some unique challenges. In particular, the existing methodologies to correct for aperiodicity in the tip vortex locations could not be easily extended to the present measurements. The difficulty stemmed from the inability to accurately determine the vortex center, which is a prerequisite for the correction procedure. A new method is proposed for determining the vortex center, as well as the vortex core properties, using a least-squares fit approach. This approach has the obvious advantage that the properties are derived from not just a few points near the vortex core, but from a much larger area of flow measurements. Results clearly demonstrate the advantage in the form of reduced variation in the estimated core properties, and also the self-consistent results obtained using three different aperiodicity correction methods.

CPAP Tips

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Full Text Available ... opinion count. Sign in ... and use a continuous positive airway pressure (CPAP) device when sleeping? Here are some tips from the U.S. Food and Drug Administration (FDA) on how to safely ...

The tonoplast intrinsic aquaporin (TIP) subfamily of Eucalyptus grandis: Characterization of EgTIP2, a root-specific and osmotic stress-responsive gene.

Science.gov (United States)

Rodrigues, Marcela I; Bravo, Juliana P; Sassaki, Flávio T; Severino, Fábio E; Maia, Ivan G

2013-12-01

Aquaporins have important roles in various physiological processes in plants, including growth, development and adaptation to stress. In this study, a gene encoding a root-specific tonoplast intrinsic aquaporin (TIP) from Eucalyptus grandis (named EgTIP2) was investigated. The root-specific expression of EgTIP2 was validated over a panel of five eucalyptus organ/tissues. In eucalyptus roots, EgTIP2 expression was significantly induced by osmotic stress imposed by PEG treatment. Histochemical analysis of transgenic tobacco lines (Nicotiana tabacum SR1) harboring an EgTIP2 promoter:GUS reporter cassette revealed major GUS staining in the vasculature and in root tips. Consistent with its osmotic-stress inducible expression in eucalyptus, EgTIP2 promoter activity was up-regulated by mannitol treatment, but was down-regulated by abscisic acid. Taken together, these results suggest that EgTIP2 might be involved in eucalyptus response to drought. Additional searches in the eucalyptus genome revealed the presence of four additional putative TIP coding genes, which could be individually assigned to the classical TIP1-5 groups. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Tip Induced Motion of Adatoms on Metal Surfaces

International Nuclear Information System (INIS)

Kuerpick, U.; Rahman, T.S.

1999-01-01

From total energy calculations we show that for certain tip-adatom separations the activation barrier for the adatom to move towards the tip disappears and the adatom experiences an attractive force in the direction of the tip. For a Cu adatom at a (100) microfaceted step on Cu(111) this happens at a lateral separation of about one lattice constant, in agreement with recent experimental findings. Simultaneously, the activation barrier in the direction away from the tip increases significantly. The details of the changes in the potential energy surface induced by the tip are found to depend on the characteristics of the tip apex and its height above the adatom. copyright 1999 The American Physical Society

Development of a New Safety Culture Assessment Method for Nuclear Power Plants (NPPs) (A study to suggest a new safety culture assessment method in nuclear power plants)

International Nuclear Information System (INIS)

Han, Sang Min; Seong, Poong Hyun

2014-01-01

This study is conducted to suggest a new safety culture assessment method in nuclear power plants. Criteria with various existing safety culture analysis methods are united, and reliability analysis methods are applied. The concept of the most representative methods, Fault Tree Analysis (FTA) and Failure Mode and Effect Analysis (FMEA), are adopted to assess safety culture. Through this application, it is expected that the suggested method will bring results with convenience and objectiveness

Development of a New Safety Culture Assessment Method for Nuclear Power Plants (NPPs) (A study to suggest a new safety culture assessment method in nuclear power plants)

Energy Technology Data Exchange (ETDEWEB)

Han, Sang Min; Seong, Poong Hyun [KAIST, Daejeon (Korea, Republic of)

2014-08-15

This study is conducted to suggest a new safety culture assessment method in nuclear power plants. Criteria with various existing safety culture analysis methods are united, and reliability analysis methods are applied. The concept of the most representative methods, Fault Tree Analysis (FTA) and Failure Mode and Effect Analysis (FMEA), are adopted to assess safety culture. Through this application, it is expected that the suggested method will bring results with convenience and objectiveness.

Arctic tipping points in an Earth system perspective.

Science.gov (United States)

Wassmann, Paul; Lenton, Timothy M

2012-02-01

We provide an introduction to the volume The Arctic in the Earth System perspective: the role of tipping points. The terms tipping point and tipping element are described and their role in current science, general debates, and the Arctic are elucidated. From a wider perspective, the volume focuses upon the role of humans in the Arctic component of the Earth system and in particular the envelope for human existence, the Arctic ecosystems. The Arctic climate tipping elements, the tipping elements in Arctic ecosystems and societies, and the challenges of governance and anticipation are illuminated through short summaries of eight publications that derive from the Arctic Frontiers conference in 2011 and the EU FP7 project Arctic Tipping Points. Then some ideas based upon resilience thinking are developed to show how wise system management could ease pressures on Arctic systems in order to keep them away from tipping points.

Modeling shoot-tip temperature in the greenhouse environment

International Nuclear Information System (INIS)

Faust, J.E.; Heins, R.D.

1998-01-01

An energy-balance model is described that predicts vinca (Catharanthus roseus L.) shoot-tip temperature using four environmental measurements: solar radiation and dry bulb, wet bulb, and glazing material temperature. The time and magnitude of the differences between shoot-tip and air temperature were determined in greenhouses maintained at air temperatures of 15, 20, 25, 30, or 35 °C. At night, shoot-tip temperature was always below air temperature. Shoot-tip temperature decreased from 0.5 to 5 °C below air temperature as greenhouse glass temperature decreased from 2 to 15 °C below air temperature. During the photoperiod under low vapor-pressure deficit (VPD) and low air temperature, shoot-tip temperature increased ≈4 °C as solar radiation increased from 0 to 600 W·m -2 . Under high VPD and high air temperature, shoot-tip temperature initially decreased 1 to 2 °C at sunrise, then increased later in the morning as solar radiation increased. The model predicted shoot-tip temperatures within ±1 °C of 81% of the observed 1-hour average shoot-tip temperatures. The model was used to simulate shoot-tip temperatures under different VPD, solar radiation, and air temperatures. Since the rate of leaf and flower development are influenced by the temperature of the meristematic tissues, a model of shoot-tip temperature will be a valuable tool to predict plant development in greenhouses and to control the greenhouse environment based on a plant temperature setpoint. (author)

Compressor airfoil tip clearance optimization system

Science.gov (United States)

Little, David A.; Pu, Zhengxiang

2015-08-18

A compressor airfoil tip clearance optimization system for reducing a gap between a tip of a compressor airfoil and a radially adjacent component of a turbine engine is disclosed. The turbine engine may include ID and OD flowpath boundaries configured to minimize compressor airfoil tip clearances during turbine engine operation in cooperation with one or more clearance reduction systems that are configured to move the rotor assembly axially to reduce tip clearance. The configurations of the ID and OD flowpath boundaries enhance the effectiveness of the axial movement of the rotor assembly, which includes movement of the ID flowpath boundary. During operation of the turbine engine, the rotor assembly may be moved axially to increase the efficiency of the turbine engine.

Tips for Postpartum Dads and Partners

Science.gov (United States)

... Blues: Partners Interview with Wade Bowen Coping with Suicide & Loss Tips for Postpartum Dads and Partners Pregnancy and postpartum mood and anxiety disorders affect the whole family. Here are some tips ...

Tipping Point

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Full Text Available ... fall furniture head injury product safety television tipover tv Watch the video in Adobe Flash format. Almost ... accidents involving young children and furniture, appliance and tv tip-overs. The force of a large television ...

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Tipping Point

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Full Text Available ... Point by CPSC Blogger September 22, 2009 appliance child Childproofing CPSC danger death electrical fall furniture head ... see news reports about horrible accidents involving young children and furniture, appliance and tv tip-overs. The ...

Tipping Point

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Full Text Available ... of a large television falling from tipping furniture can be staggering. A 50 lb. TV falls with ... story of a building. That kind of impact can kill a child or cause severe injuries. About ...

Removal of artificial dental calculus by use of conventional and diamond ultrasound tips.

Directory of Open Access Journals (Sweden)

Roberto Carlos Mourão Pinho

2017-04-01

Full Text Available Introduction: Periodontal disease is considered a public health problem and may lead to serious complications as the general health of patient. The main therapeutic procedure is scaling and root planing, which can be performed by a variety of techniques and instruments Objective:The aim of the present study was to evaluate the removal of calculus, produced artificially, by using a conventional ultrasonic tip and a diamond – CVD tip. Method: The calculus was produced with artificial sawdust and glue-based cyanoacrylate and distributed in twenty areas also standardized on two plates of acrylic resin (chemical activated, holding 10 samples per plate. Standards / samples were divided by lot into two simple groups, being A (treated with conventional tip and B (treated with CVD tip. Results:The treatment in Group A, promoted an average area of 20.48 ± 4.20 mm2 free of artificial calculus which is significantly higher (p <0.05 than the area removed in Group B (15.37 ± 5.29 mm2. Conclusion:The results showed that the conventional tip presented higher results than CVD tip for efficacy in the removal of calculus.

In vitro culture method of powdery mildew (Oidium heveae ...

African Journals Online (AJOL)

ELOHO

2012-08-23

Aug 23, 2012 ... A method for culturing powdery mildew (Oidium heveae) from isolated leaves of ... solution; d, Colour phase leaves with nutrient solution in culture dish; e, in vitro ... Plant and fungus materials .... same change trend during whole culture period. ... consistent with the field resistance identification results of.

Percutaneous radiofrequency treatment of osteoid osteoma using cool-tip electrodes

Energy Technology Data Exchange (ETDEWEB)

Martel, Jose [Departamento de Diagnostico por Imagen, Fundacion Hospital Alcorcon, Avda. de Budapest s/n, 28922 Alcorcon, Madrid (Spain)]. E-mail: jmartel@fhalcorcon.es; Bueno, Angel [Departamento de Diagnostico por Imagen, Fundacion Hospital Alcorcon, Avda. de Budapest s/n, 28922 Alcorcon, Madrid (Spain); Ortiz, Eduardo [Departamento de Cirugia ortopedica, Fundacion Hospital Alcorcon, Madrid (Spain)

2005-12-15

Objectives: To report our experience with percutaneous cool-tip radiofrequency ablation of osteoid osteomas and to evaluate clinical outcome. Methods and material: Forty-one patients with clinically and radiologically suspected osteoid osteoma were seen over a 48-month period (27 males and 14 females with a mean age of 18.7 years; range 5-43 years). Thirty-eight patients were treated by computed tomography (CT)-guided percutaneous radiofrequency ablation. The procedure was performed under regional or general anaesthesia. After location of the nidus, a 14G-bone biopsy needle is introduced into the nidus. Sampling is performed with a 17G-bone biopsy needle using a coaxial technique. The radiofrequency needle with a 10 mm active tip (cool-tip) is inserted through the biopsy needle and is connected to the radiofrequency generator for 6-8 min. Results: Primary success was obtained in 37 patients (97%) with a 100% secondary success rate. All patients are currently pain-free. No major complications occurred. Patients could resume unrestricted normal activity within 24 h. Conclusions: Percutaneous radiofrequency ablation of osteoid osteomas is an efficient and safe method that can be considered the procedure of choice for most cases.

Plasmonic Colloidal Nanoantennas for Tip-Enhanced Raman Spectrocopy

Science.gov (United States)

Dill, Tyler J.

Plasmonic nanoantennas that a support localized surface plasmon resonance (LSPR) are capable of confining visible light to subwavelength dimensions due to strong electromagnetic field enhancement at the probe tip. Nanoantenna enable optical methods such as tip-enhanced Raman spectroscopy (TERS), a technique that uses scanning probe microscopy tips to provide chemical information with nanoscale spatial resolution and single-molecule sensitivities. The LSPR supported by the probe tip is extremely sensitive to the nanoscale morphology of the nanoantenna. Control of nanoscale morphology is notoriously difficult to achieve, resulting in TERS probes with poor reproducibility. In my thesis, I demonstrate high-performance, predictable, and broadband nanospectroscopy probes that are fabricated by self-assembly. Shaped metal nanoparticles are organized into dense layers and deposited onto scanning probe tips. When coupled to a metal substrate, these probes support a strong optical resonance in the gap between the substrate and the probe, producing dramatic field enhancements. I show through experiment and electromagnetic modeling that close-packed but electrically isolated nanoparticles are electromagnetically coupled. Hybridized LSPRs supported by self-assembled nanoparticles with a broadband optical response, giving colloidal nanoantenna a high tolerance for geometric variation resulting from fabrication. I find that coupled nanoparticles act as a waveguide, transferring energy from many neighboring nanoparticles towards the active TERS apex. I also use surface-enhanced Raman spectroscopy (SERS) to characterize the effects of nanoparticle polydispersity and gap height on the Raman enhancement. These colloidal probes have consistently achieved dramatic Raman enhancements in the range of 108-109 with sub-50 nm spatial resolution. Furthermore, in contrast to other nanospectroscopy probes, these colloidal probes can be fabricated in a scalable fashion with a batch

CPAP Tips

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Tipping Point

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Full Text Available ... third story of a building. That kind of impact can kill a child or cause severe injuries. ... to prevent a tip-over tragedy. Share Post Facebook Twitter Google Plus Reddit Connect with Me:  Visit ...

Continuum damage mechanics analysis of crack tip zone

International Nuclear Information System (INIS)

Yinchu, L.; Jianping, Z.

1989-01-01

The crack tip field and its intensity factor play an important role in fracture mechanics. Generally, the damage such as microcracks, microvoids etc. will initiate and grow in materials as the cracked body is subjected to external loadings, especially in the crack tip zone. The damage evolution will load to the crack tip damage field and the change of the stress, strain and displacement fields of cracks tip zone. In this paper, on the basis of continuum damage mechanics, the authors have derived the equations which the crack tip field and its intensity factor must satisfy in a loading process, calculated the angle distribution curves of stress, strain and displacement fields in a crack tip zone and have compared them with the corresponding curves of HRR field and linear elastic field in undamaged materials. The equations of crack tip field intensity factors have been solved and its solutions give the variation of the field intensity factors with the loading parameter

Gradual approach to refinement of the nasal tip: surgical results

Directory of Open Access Journals (Sweden)

Thiago Bittencourt Ottoni de Carvalho

2015-02-01

Full Text Available Introduction: The complexity of the nasal tip structures and the impact of surgical maneuvers make the prediction of the final outcome very difficult. Therefore, no single technique is enough to correct the several anatomical presentations, and adequate preoperative planning represents the basis of rhinoplasty. Objective: To present results of rhinoplasty, through the gradual surgical approach to nasal tip definition based on anatomical features, and to evaluate the degree of patient satisfaction after the surgical procedure. Methods: Longitudinal retrospective cohort study of the medical charts of 533 patients of both genders who underwent rhinoplasty from January of 2005 to January of 2012 was performed. Cases were allocated into seven groups: (1 no surgery on nasal tip; (2 interdomal breakup; (3 cephalic trim; (4 domal suture; (5 shield-shaped graft; (6 vertical dome division; (7 replacement of lower lateral cartilages. Results: Group 4 was the most prevalent. The satisfaction rate was 96% and revision surgery occurred in 4% of cases. Conclusion: The protocol used allowed the implementation of a gradual surgical approach to nasal tip definition with the nasal anatomical characteristics, high rate of patient satisfaction with the surgical outcome, and low rate of revision.

Tip enhancement

CERN Document Server

Kawata, Satoshi

2007-01-01

This book discusses the recent advances in the area of near-field Raman scattering, mainly focusing on tip-enhanced and surface-enhanced Raman scattering. Some of the key features covered here are the optical structuring and manipulations, single molecule sensitivity, analysis of single-walled carbon nanotubes, and analytic applications in chemistry, biology and material sciences. This book also discusses the plasmonic materials for better enhancement, and optical antennas. Further, near-field microscopy based on second harmonic generation is also discussed. Chapters have been written by some of the leading scientists in this field, who present some of their recent work in this field.·Near-field Raman scattering·Tip-enhanced Raman spectroscopy·Surface-enhanced Raman spectroscopy·Nano-photonics·Nanoanalysis of Physical, chemical and biological materials beyond the diffraction limits·Single molecule detection

Numerical investigation of tip leakage vortex

OpenAIRE

Fredriksen, Vegard

2017-01-01

The Kaplan turbine has a small clearance gap between the blade tip and casing to allow the blades to rotate freely. This clearance gap is the cause of an undesirable Tip Leakage Vortex (TLV). A TLV might reduce the turbine efficiency, erode the turbine blades or cause instabilities for the power output. A literature study indicated that the tip clearance gap was a critical parameter affecting the behavior of the TLV. A research gap was observed for an operating Kaplan turbine where the ...

Optical fiber meta-tips

Science.gov (United States)

Principe, Maria; Micco, Alberto; Crescitelli, Alessio; Castaldi, Giuseppe; Consales, Marco; Esposito, Emanuela; La Ferrara, Vera; Galdi, Vincenzo; Cusano, Andrea

2016-04-01

We report on the first example of a "meta-tip" configuration that integrates a metasurface on the tip of an optical fiber. Our proposed design is based on an inverted-Babinet plasmonic metasurface obtained by patterning (via focused ion beam) a thin gold film deposited on the tip of an optical fiber, so as to realize an array of rectangular aperture nanoantennas with spatially modulated sizes. By properly tuning the resonances of the aperture nanoantennas, abrupt variations can be impressed in the field wavefront and polarization. We fabricated and characterized several proof-of-principle prototypes operating an near-infrared wavelengths, and implementing the beam-steering (with various angles) of the cross-polarized component, as well as the excitation of surface waves. Our results pave the way to the integration of the exceptional field-manipulation capabilities enabled by metasurfaces with the versatility and ubiquity of fiber-optics technological platforms.

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Full Text Available ... Get YouTube Red. Working... Not now Try it free Find out why Close CPAP Tips from FDA ... safely and effectively use your CPAP device. Category Education License Standard YouTube License Show more Show less ...

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Nantucket Pine Tip Moth Control and Loblolly Pine Growth in Intensive Pine Culture: Two-Year Results

Science.gov (United States)

David L. Kulhavy; Jimmie L. Yeiser; L. Allen Smith

2004-01-01

Twenty-two treatments replicated four times were applied to planted loblolly pine, Pinus taeda L. on bedded industrial forest land in east Texas for measurement of growth impact of Nantucket pine tip moth (NPTM), Rhyacionia frustrana (Comstock), and effects on pine growth over 2 years. Treatments were combinations of Velpar, Oust, and Arsenal...

Note: Microelectrode-shielding tip for scanning probe electron energy spectroscopy

Science.gov (United States)

Huang, Wei; Li, Zhean; Xu, Chunkai; Liu, Jian; Xu, Chunye; Chen, Xiangjun

2018-04-01

We report a novel microelectrode-shielding tip (ME tip) for scanning probe electron energy spectroscopy (SPEES). The shielding effect of this tip is studied through comparing the detection efficiency with the normal tip by both experiment and simulation. The results show that the backscattering count rate detected by the SPEES instrument using the normal tip begins to decrease as the tip approaches to the sample surface within 21 μm, while that using the ME tip only starts to drop off within 1 μm. This indicates that the electron energy spectra can be measured with the ME tip at a much closer tip-sample distance. Furthermore, it is also demonstrated that the ME tip can be used to obtain topography of the sample surface in situ simultaneously.

Culture, Method, and the Content of Self-Concepts: Testing Trait, Individual-Self-Primacy, and Cultural Psychology Perspectives.

Science.gov (United States)

Del Prado, Alicia M; Church, A Timothy; Katigbak, Marcia S; Miramontes, Lilia G; Whitty, Monica; Curtis, Guy J; de Jesús Vargas-Flores, José; Ibáñez-Reyes, Joselina; Ortiz, Fernando A; Reyes, Jose Alberto S

2007-12-01

Three theoretical perspectives on cultural universals and differences in the content of self-concepts were tested in individualistic (United States, n = 178; Australia, n = 112) and collectivistic (Mexico, n = 157; Philippines, n = 138) cultures, using three methods of self-concept assessment. Support was found for both trait perspectives and the individual-self-primacy hypothesis. In contrast, support for cultural psychology hypotheses was limited because traits and other personal attributes were not more salient, or social attributes less salient, in individualistic cultures than collectivistic cultures. The salience of some aspects of self-concept depended on the method of assessment, calling into question conclusions based on monomethod studies.

Maritime and Underwater Cultural Heritage in South Africa: The Development of Relevant Management Strategies in the Historical Maritime Context of the Southern Tip of Africa

Science.gov (United States)

Sharfman, Jonathan; Boshoff, Jaco; Parthesius, Robert

2012-10-01

South Africans have a long association with water. It has provided a source of food, a medium for trade and a catalyst for migration and development. The country's geographical position as a crossroads of maritime trade between Europe and the East means that its history is inextricably linked to the history of the rest of the world. The result is a multi-faceted representation of sites, objects and mythologies related to water and maritime heritage that reflect not only local historical and social development, but global cultural change as well. Given the importance of South Africa's underwater cultural heritage (UCH), managers have grappled with management principles, ethics and theoretical models in an effort to produce and enforce heritage legislation that is relevant and effective. This paper outlines South Africa's maritime context from 1.5 million years ago until the present, summarises legislative and mitigation developments over the past half century and provides details of current trends in maritime archaeology and UCH management at the southern tip of Africa. Training programmes and public awareness are keys to this strategy to bring UCH and maritime archaeology into the mainstream and counter treasure hunting and looting of this rich, friable resource.

Injector tip for an internal combustion engine

Science.gov (United States)

Shyu, Tsu Pin; Ye, Wen

2003-05-20

This invention relates to a the tip structure of a fuel injector as used in a internal combustion engine. Internal combustion engines using Homogeneous Charge Compression Ignition (HCCI) technology require a tip structure that directs fuel spray in a downward direction. This requirement necessitates a tip design that is capable of withstanding mechanical stresses associated with the design.

Dialectical Method and the Critical Political Economy of Culture

Directory of Open Access Journals (Sweden)

Brice Nixon

2012-05-01

Full Text Available This article argues that the quality that defines critical political economy is its critical method. Definitions of the critical political economy of culture are considered and shown to focus on specific theoretical concerns while not fully addressing the fundamental issue of method. Method is here discussed in terms of the way human reason is used to produce knowledge. A critical method for Marx is a historical materialist dialectical method, thus this paper argues for a deeper consideration of the Marxist dialectical method in relation to critical political-economic theorizing. Sources for methodological consideration from Marx to 20th-century Western Marxists are outlined. The potential contribution of the Marxist dialectical method in the continued development of the critical political economy of culture is demonstrated by showing the possibility of developing a complementary critical political economy of consciousness. Smythe’s theorizing of audiences as workers is considered as a useful starting point, and its potential development through incorporation of the work of other critical scholars of media and culture is outlined.

CPAP Tips

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Probing the effect of tip pressure on fungal growth: Application to Aspergillus nidulans

Science.gov (United States)

González-Bermúdez, Blanca; Li, Qingxuan; Guinea, Gustavo V.; Peñalva, Miguel A.; Plaza, Gustavo R.

2017-08-01

The study of fungal cells is of great interest due to their importance as pathogens and as fermenting fungi and for their appropriateness as model organisms. The differential pressure between the hyphal cytoplasm and the bordering medium is essential for the growth process, because the pressure is correlated with the growth rate. Notably, during the invasion of tissues, the external pressure at the tip of the hypha may be different from the pressure in the surrounding medium. We report the use of a method, based on the micropipette-aspiration technique, to study the influence of this external pressure at the hyphal tip. Moreover, this technique makes it possible to study hyphal growth mechanics in the case of very thin hyphae, not accessible to turgor pressure probes. We found a correlation between the local pressure at the tip and the growth rate for the species Arpergillus nidulans. Importantly, the proposed method allows one to measure the pressure at the tip required to arrest the hyphal growth. Determining that pressure could be useful to develop new medical treatments for fungal infections. Finally, we provide a mechanical model for these experiments, taking into account the cytoplasm flow and the wall deformation.

Accurate measurement of Atomic Force Microscope cantilever deflection excluding tip-surface contact with application to force calibration

Energy Technology Data Exchange (ETDEWEB)

Slattery, Ashley D.; Blanch, Adam J.; Quinton, Jamie S.; Gibson, Christopher T., E-mail: christopher.gibson@flinders.edu.au

2013-08-15

Considerable attention has been given to the calibration of AFM cantilever spring constants in the last 20 years. Techniques that do not require tip-sample contact are considered advantageous since the imaging tip is not at risk of being damaged. Far less attention has been directed toward measuring the cantilever deflection or sensitivity, despite the fact that the primary means of determining this factor relies on the AFM tip being pressed against a hard surface, such as silicon or sapphire; which has the potential to significantly damage the tip. A recent method developed by Tourek et al. in 2010 involves deflecting the AFM cantilever a known distance from the imaging tip by pressing the cantilever against a sharpened tungsten wire. In this work a similar yet more precise method is described, whereby the deflection of the cantilever is achieved using an AFM probe with a spring constant much larger than the test cantilever, essentially a rigid cantilever. The exact position of loading on the test cantilever was determined by reverse AFM imaging small spatial markers that are milled into the test cantilever using a focussed ion beam. For V shaped cantilevers it is possible to reverse image the arm intersection in order to determine the exact loading point without necessarily requiring FIB milled spatial markers, albeit at the potential cost of additional uncertainty. The technique is applied to tip-less, beam shaped and V shaped cantilevers and compared to the hard surface contact technique with very good agreement (on average less than 5% difference). While the agreement with the hard surface contact technique was very good the error on the technique is dependent upon the assumptions inherent in the method, such as cantilever shape, loading point distance and ratio of test to rigid cantilever spring constants. The average error ranged between 2 to 5% for the majority of test cantilevers studied. The sensitivity derived with this technique can then be used to

Management of Bleeding Duodenal Varices with Combined TIPS Decompression and Trans-TIPS Transvenous Obliteration Utilizing 3% Sodium Tetradecyl Sulfate Foam Sclerosis.

Science.gov (United States)

Saad, Wael E; Lippert, Allison; Schwaner, Sandra; Al-Osaimi, Abdullah; Sabri, Saher; Saad, Nael

2014-01-01

Endoscopic experience in the management of duodenal varices (DVs) is limited and challenging given the anatomic constraints and limited experience. The endovascular management of DVs is not yet established and the controversy of whether to manage them by decompression with a transjugular intrahepatic portosystemic shunt (TIPS) or by transvenous obliteration is unresolved. In the literature, the 6-12 month rebleeding rate of DVs after TIPS is 21-37% and after transvenous obliteration is 13%. The purpose of the study is to evaluate the clinical outcome of combined TIPS decompression and transvenous obliteration/sclerosis. This is a retrospective study (case series) of two institutions, evaluating patients who underwent TIPS and/or transvenous obliteration/sclerosis for bleeding DVs (from January 2009 to June 2013). TIPS was performed according to a standard procedure using covered stents. Transvenous obliteration (variceal sclerosis) from the systemic and/or portal venous circulation was performed utilizing 3% sodium tetradecyl sulfate foam. Transvenous obliteration was commonly augmented with coils and/or vascular plugs. Technical (technical success of establishing TIPS and completely obliterating the DVs) and clinical outcomes (rebleeding rate and survival) were evaluated. Five patients with liver cirrhosis presenting with bleeding DVs were included in the study with all eventually (and coincidentally) receiving TIPS and transvenous obliteration. Two of the five patients underwent concomitant TIPS and transvenous obliteration in the same procedural setting. However, three patients underwent transvenous obliteration due to bleeding despite a patent TIPS that had been previously placed. The average time from TIPS placement to transvenous obliteration was 125 days (range: 3-324 days). After having both procedures, there was no rebleeding in the patients during a mean follow-up period of 22 months (6-50 months). Coils and/or metallic vascular plugs were used to augment

Cultural adaptation and translation of measures: an integrated method.

Science.gov (United States)

Sidani, Souraya; Guruge, Sepali; Miranda, Joyal; Ford-Gilboe, Marilyn; Varcoe, Colleen

2010-04-01

Differences in the conceptualization and operationalization of health-related concepts may exist across cultures. Such differences underscore the importance of examining conceptual equivalence when adapting and translating instruments. In this article, we describe an integrated method for exploring conceptual equivalence within the process of adapting and translating measures. The integrated method involves five phases including selection of instruments for cultural adaptation and translation; assessment of conceptual equivalence, leading to the generation of a set of items deemed to be culturally and linguistically appropriate to assess the concept of interest in the target community; forward translation; back translation (optional); and pre-testing of the set of items. Strengths and limitations of the proposed integrated method are discussed. (c) 2010 Wiley Periodicals, Inc.

DO SLOVENIAN DEALERS USE TECHNIQUES FOR INCREASING THEIR TIPS?

Directory of Open Access Journals (Sweden)

Andrej Raspor

2016-05-01

Full Text Available In 1996 Michael Lynn introduced the idea that restaurant managers could increase tips for their waiters and thus increase turnover by training the waiters to engage tip-enhancing behaviours. Since then, the list of tip-enhancing behaviours has expanded. Therefore the potential to increase tips is more accessible. The purpose of this paper was to examine how Slovenian dealers use strategies to increase their tips. We tested fourteen techniques to increase tips. The study was carried out among 473 gaming employees, 279 of which are dealers, in the Slovenian gaming industry, in order to find out how they use these techniques and which of them can bring about an increase in their tips. The study showed that Slovenian dealers mostly do not use these techniques, and that the dealers who do use them tend to receive tips more often. The findings imply that managers and employees should be informed of these techniques in order to increase tips and their overall income. Practical implications are that we suggest that management considers these ideas for increasing flexibility and reducing the cost of work: (1 informing dealers on ways of increasing tips, (2 including the acquisition of this specific knowledge in their career plans, (3 carrying out a reform of the reward system which would include tips. Social implications will be shown in a higher gaming revenue. It is very likely – as shown in our research – that employees will receive higher wages as these will be topped up by tips. The state, in turn, will collect more taxes.

Numerical Simulation of LVAD Inflow Cannulas with Different Tip

Directory of Open Access Journals (Sweden)

Guang-Mao Liu

2012-01-01

Full Text Available The tip structure of LVAD inflow cannula is one of major factors to lead adverse events such as thrombosis and suction leading to obstruction. In this research, four kinds of tips that had been used in inflow cannulas were selected and designed. The flow field of the four inflow cannulas inserted into the apex of left ventricle (LV was numerically computed by computational fluid dynamics. The flow behavior was analyzed in order to compare the blood compatibility and suction in left ventricle and cannulas after the inflow cannulas with different tips were inserted to the apex of LV. The results showed that the cannula tip structure affected the LVAD performance. Among these four cannulas, the trumpet-tipped inflow cannula owned the best performance in smooth flow velocity distribution without backflow or low-velocity flow so that it was the best in blood compatibility. Nevertheless, the caged tipped cannula was the worst in blood compatibility. And the blunt-tipped and beveled tipped inflow cannulas may obstruct more easily than trumpet and caged tipped inflow cannulas because of their shape. The study indicated that the trumpet tip was the most preferable for the inflow cannula of long-term LVAD.

Multiple Iterations of Bundle Adjustment for the Position Measurement of Fiber Tips on LAMOST

Directory of Open Access Journals (Sweden)

Feng Mingchi

2014-08-01

Full Text Available In the astronomical observation process of multi-object fiber spectroscopic telescope, the position measurement of fiber tips on the focal plane is difficult and critical, and is directly related to subsequent observation and ultimate data quality. The fibers should precisely align with the celestial target. Hence, the precise coordinates of the fiber tips are obligatory for tracking the celestial target. The accurate movement trajectories of the fiber tips on the focal surface of the telescope are the critical problem for the control of the fiber positioning mechanism. According to the special structure of the LAMOST telescope and the composition of the initial position error, this paper aims at developing a high precision and robust measurement method based on multiple iterations of bundle adjustment with a few control points. The measurement theory of the proposed methodology has been analyzed, and the measurement accuracy has been evaluated. The experimental results indicate that the new method is more accurate and more reliable than the polynomial fitting method. The maximum position error of the novel measurement algorithm of fiber tips with simulated and real data is 65.3 μm, and most of the position errors conform to the accuracy requirement (40 μm.

Combined Scanning Nanoindentation and Tunneling Microscope Technique by Means of Semiconductive Diamond Berkovich Tip

International Nuclear Information System (INIS)

Lysenko, O; Novikov, N; Gontar, A; Grushko, V; Shcherbakov, A

2007-01-01

A combined Scanning Probe Microscope (SPM) - nanoindentation instrument enables submicron resolution indentation tests and in-situ scanning of structure surfaces. A newly developed technique is based on the scanning tunneling microscopy (STM) with integrated Berkovich diamond semiconductive tip. Diamond tips for a combined SPM were obtained using the developed procedure including the synthesis of the semiconductive borondoped diamond monocrystals by the temperature gradient method at high pressure - high temperature conditions and fabrication of the tips from these crystals considering their zonal structure. Separately grown semiconductive diamond single crystals were studied in order to find the best orientation of diamond crystals. Optimal scanning characteristics and experimental data errors were calculated by an analysis of the general functional dependence of the tunneling current from properties of the tip and specimen. Tests on the indentation and scanning of the gold film deposited on the silicon substrate employing the fabricated tips demonstrated their usability, acceptable resolution and sensitivity

Fringe Analysis around an Inclined Crack Tip of Finite-Width Plate under Tensile Load by Photoelastic Phase-Shifting Method

International Nuclear Information System (INIS)

Li, Weizheng; Baek, Tae Hyun; Lee, Byung Hee; Seo, Jin; Hong, Dong Pyo

2012-01-01

Photoelasticity is a technique of experimental methods and has been widely used in various domains of engineering to determine the stress distribution of structures. Without complicated mathematical formulation, this technique can conveniently provide a fairly accurate whole-field stress analysis for a mechanical structure. Here, stress distribution around an inclined crack tip of finite-width plate is studied by 8-step phase-shifting method. This method is a kind of photoelastic phase-shifting techniques and can be used for the determination of the phase values of isochromatics and isoclinics. According to stress-optic law, the stress distribution could be obtained from fringe patterns. The results obtained by polariscope arrangement combined with 8-step method and ABAQUS FEM simulations are compared with each other. Good agreement between them shows that 8-step phase-shifting method is reliable and can be used for determination of stress by experiment

The U.S. National "Tips from Former Smokers" Antismoking Campaign: Promoting Awareness of Smoking-Related Risks, Cessation Resources, and Cessation Behaviors

Science.gov (United States)

Huang, Li-Ling; Thrasher, James F.; Abad, Erika Nayeli; Cummings, K. Michael; Bansal-Travers, Maansi; Brown, Abraham; Nagelhout, Gera E.

2015-01-01

Objective: Evaluate the second flight of the U.S. "Tips From Former Smokers" (Tips) campaign. Method: Data were analyzed from an online consumer panel of U.S. adult smokers before (n = 1,404) and after (n = 1,401) the 2013 Tips campaign launch. Generalized estimating equation models assessed whether the Tips advertisement recall was…

Tissue culture of adult larch as a tool for breeding purposes

Energy Technology Data Exchange (ETDEWEB)

Ewald, D.; Kretzschmar, U. [Federal Research Centre of Forestry and Forest Products, Waldsieversdorf (Germany). Inst. for Forest Tree Biology

1995-12-31

Aimed at the identical reproduction of genotypes which are considered superior different methods were tested to establish and to propagate tissue cultures from old larch trees (L. decidua, L. kaempferi, L. sukaczewii, L. gmelinii, L. eurolepis). Serial subcultures without phytohormones (shoot tip propagation) led to the establishment of clone lines. After ten subcultures propagation velocity, shoot morphology and rooting behavior were similar to juvenile plant material. Serial subcultures which included a cytokinin induction led to the formation of adventitious shoot clusters (adventitious bud propagation). Adventitious shoots derived from male flowers of one L. kaempferi clone could be propagated via shoot tip propagation. Micrografting of meristems in vitro resulted in a regained rooting capacity of green cuttings from micrografts. Combining these in vitro techniques offers now the possibility to propagate selected mature larch trees for different breeding purposes. 23 refs, 5 figs, 2 tabs

Tissue culture of adult larch as a tool for breeding purposes

Energy Technology Data Exchange (ETDEWEB)

Ewald, D; Kretzschmar, U [Federal Research Centre of Forestry and Forest Products, Waldsieversdorf (Germany). Inst. for Forest Tree Biology

1996-12-31

Aimed at the identical reproduction of genotypes which are considered superior different methods were tested to establish and to propagate tissue cultures from old larch trees (L. decidua, L. kaempferi, L. sukaczewii, L. gmelinii, L. eurolepis). Serial subcultures without phytohormones (shoot tip propagation) led to the establishment of clone lines. After ten subcultures propagation velocity, shoot morphology and rooting behavior were similar to juvenile plant material. Serial subcultures which included a cytokinin induction led to the formation of adventitious shoot clusters (adventitious bud propagation). Adventitious shoots derived from male flowers of one L. kaempferi clone could be propagated via shoot tip propagation. Micrografting of meristems in vitro resulted in a regained rooting capacity of green cuttings from micrografts. Combining these in vitro techniques offers now the possibility to propagate selected mature larch trees for different breeding purposes. 23 refs, 5 figs, 2 tabs

Productivity tips for developers

CERN Multimedia

CERN. Geneva

2018-01-01

I like to read about productivity tools and techniques, but the problem is - most of them are completely overrated, the tips are not that useful or they are too difficult to implement. But, sometimes I can find some stuff that really makes me think "damn, how could I live without this before?!". Today, I would like to share some of them and hopefully hear about the tips and tricks that you use. Maybe we can find a way to share them somehow (github repo/forum)?

Temperature-controlled irrigated tip radiofrequency catheter ablation

DEFF Research Database (Denmark)

Petersen, H H; Chen, X; Pietersen, Adrian

1998-01-01

INTRODUCTION: In patients with ventricular tachycardias due to structural heart disease, catheter ablation cures radiofrequency ablation. Irrigated tip radiofrequency ablation using power control and high infusion rates enlarges lesion......: We conclude that temperature-controlled radiofrequency ablation with irrigated tip catheters using low target temperature and low infusion rate enlarges lesion size without increasing the incidence of cratering and reduces coagulum formation of the tip....

Tipping Point

Medline Plus

Full Text Available ... to prevent a tip-over tragedy. Share Post Facebook Twitter Google Plus Reddit Connect with Me:  Visit other Web Sites Maintained by CPSC: cpsc.gov| poolsafely.gov| recalls.gov| saferproducts.gov Privacy, Security, and Legal Notice | Accessibility Policy | Open Government @ ...

The discussion on the qualitative and quantitative evaluation methods for safety culture

International Nuclear Information System (INIS)

Gao Kefu

2005-01-01

The fundamental methods for safely culture evaluation are described. Combining with the practice of the quantitative evaluation of safety culture in Daya Bay NPP, the quantitative evaluation method for safety culture are discussed. (author)

Meristem Culture of Aloe vera L

International Nuclear Information System (INIS)

Kay Thi Mya; Thida Myint; Myo Han; Khin Maung Sein

2005-10-01

Shoot tips of Aloe vera L were excised and inoculated in basal and modified MS (Murashige and Skoog, 1962) medium. Growth regulators and growth factors were supplemented to the basal medium. Development of explants, initiation of callus and multiplication of shoots in culture were recorded.

Potential Success and Barrier Factors for Implementation of the Transition to Independence (TIP Model

Directory of Open Access Journals (Sweden)

Christopher M. Kalinyak

2017-01-01

Full Text Available In this qualitative study, 28 key stakeholders who work with transition-aged youth participated in focus group discussions addressing success and barrier factors regarding implementation of a transition to independence process (TIP program for youth, ages 14–29, in three Midwestern cities. All participants had prior knowledge of TIP. The paradigm shift to client-oriented goals and services was acknowledged by respondents as the prime benefit of TIP; youth are more motivated to follow through on self-determined goals. Barrier factors for providers involved collaboration with agencies adhering to provider-oriented interventions, provision of TIP methods training, and reallocation of time and money. Barrier factors for youth involved mistrust of service providers, overcoming maturational deficits, and acquiring and maintaining relationships, reputations, and social supports.

Calculated shape dependence of electromagnetic field in tip-enhanced Raman scattering by using a monopole antenna model

Science.gov (United States)

Kitahama, Yasutaka; Itoh, Tamitake; Suzuki, Toshiaki

2018-05-01

To evaluate the shape of an Ag tip with regard to tip-enhanced Raman scattering (TERS) signal, the enhanced electromagnetic (EM) field and scattering spectrum, arising from surface plasmon resonance at the apex of the tip, were calculated using a finite-difference time domain (FDTD) method. In the calculated forward scattering spectra from the smooth Ag tip, the band appeared within the visible region, similar to the experimental results and calculation for a corrugated Ag cone. In the FDTD calculation of TERS, the Ag tip acting as a monopole antenna was adopted by insertion of a perfect electric conductor between the root of the tip and a top boundary surface of the calculation space. As a result, the EM field was only enhanced at the apex. The shape dependence i.e. the EM field calculated at the apex with various curvatures on the different tapered tips, obtained using the monopole antenna model, was different from that simulated using a conventional dipole antenna model.

TIPS Evaluation Project Retrospective Study: Wave 1 and 2.

Science.gov (United States)

Hubbard, Susan M.; Mulvey, Kevin P.

2003-01-01

Measured substance abuse treatment professionals' knowledge, attitudes, and practices regarding the Treatment Improvement Protocol (TIP) series and the 28 TIPs. Results for 3,267 respondents in wave 1 and 1,028 in wave 2 indicate that almost half of all professionals were aware of the TIPs. Attitudes toward TIPs were positive, but professionals…

The Influence of Explant Types and Orientation on in Vitro Culture

Directory of Open Access Journals (Sweden)

Kamnoon KANCHANAPOOM

2011-08-01

Full Text Available Inflorescence, apical and lateral buds of Musa balbisiana ‘Kluai Hin’ (BBB group were used to culture on MS medium supplemented with 22 μM BA and 15% (v/v coconut water. Comparison of bud orientation showed that the best response of in vitro shoot tip proliferation was obtained with abaxial surface of buds lying down i.e. one side touching the medium (tilt. Mass propagation of shoot tips was obtained when cultured buds on MS medium containing 44 μM BA. Rooting was achieved by transferring the isolated shoots to MS basal medium without growth regulators. Rooted plantlets were acclimatized and successfully established in soil.

Magnetic elements for switching magnetization magnetic force microscopy tips

International Nuclear Information System (INIS)

Cambel, V.; Elias, P.; Gregusova, D.; Martaus, J.; Fedor, J.; Karapetrov, G.; Novosad, V.

2010-01-01

Using combination of micromagnetic calculations and magnetic force microscopy (MFM) imaging we find optimal parameters for novel magnetic tips suitable for switching magnetization MFM. Switching magnetization MFM is based on two-pass scanning atomic force microscopy with reversed tip magnetization between the scans. Within the technique the sum of the scanned data with reversed tip magnetization depicts local atomic forces, while their difference maps the local magnetic forces. Here we propose the design and calculate the magnetic properties of tips suitable for this scanning probe technique. We find that for best performance the spin-polarized tips must exhibit low magnetic moment, low switching fields, and single-domain state at remanence. The switching field of such tips is calculated and optimum shape of the Permalloy elements for the tips is found. We show excellent correspondence between calculated and experimental results for Py elements.

Thermoelectric voltage at a nanometer-scale heated tip point contact

Science.gov (United States)

Fletcher, Patrick C.; Lee, Byeonghee; King, William P.

2012-01-01

We report thermoelectric voltage measurements between the platinum-coated tip of a heated atomic force microscope (AFM) cantilever and a gold-coated substrate. The cantilevers have an integrated heater-thermometer element made from doped single crystal silicon, and a platinum tip. The voltage can be measured at the tip, independent from the cantilever heating. We used the thermocouple junction between the platinum tip and the gold substrate to measure thermoelectric voltage during heating. Experiments used either sample-side or tip-side heating, over the temperature range 25-275 °C. The tip-substrate contact is ˜4 nm in diameter and its average measured Seebeck coefficient is 3.4 μV K-1. The thermoelectric voltage is used to determine tip-substrate interface temperature when the substrate is either glass or quartz. When the non-dimensional cantilever heater temperature is 1, the tip-substrate interface temperature is 0.593 on glass and 0.125 on quartz. Thermal contact resistance between the tip and the substrate heavily influences the tip-substrate interface temperature. Measurements agree well with modeling when the tip-substrate interface contact resistance is 108 K W-1.

Suggestions on the Development of Safety Culture Assessment Method

International Nuclear Information System (INIS)

Choi, Young Sung; Choi, Kwang Sik; Kim, Woong Sik

2006-01-01

Several efforts have been made to assess safety culture of organization that operates nuclear power plants in Korea. The MOST and KINS played a major role to develop assessment methods and KHNP applied them to its NPPs. This paper explains the two methods developed by KINS briefly and presents the insights obtained from the two different applications. It concludes with some suggestions for safety culture assessment based on the insights

Photonic jet etching: Justifying the shape of optical fiber tip

Science.gov (United States)

Abdurrochman, Andri; Zelgowski, Julien; Lecler, Sylvain; Mermet, Frédéric; Tumbelaka, Bernard; Fontaine, Joël

2016-02-01

Photonic jet (PJ) is a low diverging and highly concentrated beam in the shadow side of dielectric particle (cylinder or sphere). The concentration can be more than 200 times higher than the incidence wave. It is a non-resonance phenomenon in the near-field can propagate in a few wavelengths. Many potential applications have been proposed, including PJ etching. Hence, a guided-beam is considered increasing the PJ mobility control. While the others used a combination of classical optical fibers and spheres, we are concerned on a classical optical fiber with spherical tip to generate the PJ. This PJ driven waveguide has been realized using Gaussian mode beam inside the core. It has different variable parameters compared to classical PJ, which will be discussed in correlation with the etching demonstrations. The parameters dependency between the tip and PJ properties are complex; and theoretical aspect of this interaction will be exposed to justify the shape of our tip and optical fiber used in our demonstrations. Methods to achieve such a needed optical fiber tip will also be described. Finally the ability to generate PJ out of the shaped optical fiber will be experimentally demonstrated and the potential applications for material processing will be exposed.

Effects of plastic anisotropy on crack-tip behaviour

DEFF Research Database (Denmark)

Legarth, Brian Nyvang; Tvergaard, Viggo; Kuroda, Mitsutoshi

2002-01-01

For a crack in a homogeneous material the effect of plastic anisotropy on crack-tip blunting and on the near-tip stress and strain fields is analyzed numerically. The full finite strain analyses are carried out for plane strain under small scale yielding conditions, with purely symmetric mode I...... loading remote from the crack-tip. In cases where the principal axes of the anisotropy are inclined to the plane of the crack it is found that the plastic zones as well as the stress and strain fields just around the blunted tip of the crack become non-symmetric. In these cases the peak strain...... on the blunted tip occurs off the center line of the crack, thus indicating that the crack may want to grow in a different direction. When the anisotropic axes are parallel to the crack symmetry is retained, but the plastic zones and the near-tip fields still differ from those predicted by standard isotropic...

Embolization with the Amplatzer Vascular Plug in TIPS Patients

International Nuclear Information System (INIS)

Pattynama, Peter M. T.; Wils, Alexandra; Linden, Edwin van der; Dijk, Lukas C. van

2007-01-01

Vessel embolization can be a valuable adjunct procedure in transjugular intrahepatic portosystemic shunt (TIPS). During the creation of a TIPS, embolization of portal vein collaterals supplying esophageal varices may lower the risk of secondary rebleeding. And after creation of a TIPS, closure of the TIPS itself may be indicated if the resulting hepatic encephalopathy severely impairs mental functioning. The Amplatzer Vascular Plug (AVP; AGA Medical, Golden Valley, MN) is well suited for embolization of large-diameter vessels and has been employed in a variety of vascular lesions including congenital arteriovenous shunts. Here we describe the use of the AVP in the context of TIPS to embolize portal vein collaterals (n = 8) or to occlude the TIPS (n = 2)

Shoot regeneration of limau purut (citrus hystrix) using shoot tip: assessment of calcium gluconate and silver nitrate in overcoming premature leaf senescence

International Nuclear Information System (INIS)

Eng, W.H.; Aziz, M.A.; Sinniah, U.R.

2014-01-01

This study was carried out to establish an optimum In vitro shoot multiplication system using shoot tip explants derived from 7 week-old seedlings of Citrus hystrix. In the first experiment, shoot tips were cultured on Murashige and Skoog (MS) medium supplemented with 0-13.33 mu M 6-benzylaminopurine (BAP) for 8 weeks. Shoot tips cultured on 2.22 mu M BAP produced the highest mean number of shoots (3.42 shoots) but the shoots had low number of leaves (1.14 leaves) due to the occurrence of premature leaf senescence and callus formation. Meanwhile, the medium devoid of BAP produced the lowest mean number of shoots (1.50 shoots) but highest mean number of leaves (5.41 leaves) indicating that BAP was likely responsible for the premature leaf senescence. In order to overcome the occurrence of premature leaf senescence on medium with BAP, a second experiment was carried out whereby shoot tips were cultured on medium containing 2.22 micro M BAP fortified with 2.00, 4.00 and 6.00 mM calcium gluconate (Ca-glu) and a control treatment with 2.22 mu M BAP. The shoot and leaf numbers were increased with the addition of 4.00 and 6.00 mM Ca-glu. The presence of Ca-glu reduced premature leaf senescence and callus formation to some extent. In the third experiment, the addition of silver nitrate (AgNO/sub 3/) at 10-80 micro M in media with 2.22 micro M BAP and 2.22 micro M BAP + 4 mM Ca-glu could totally overcome premature leaf senescence and callus formation. Media supplemented with 2.22 mirco M BAP + 4 mM Ca-glu + 20 micro M AgNOsub 3/ significantly induced among the highest mean number of shoots and highest mean number of leaves per shoot. (author)

Microneedles array with biodegradable tips for transdermal drug delivery

Science.gov (United States)

Iliescu, Ciprian; Chen, Bangtao; Wei, Jiashen; Tay, Francis E. H.

2008-12-01

The paper presented an enhancement solution for transdermal drug delivery using microneedles array with biodegradable tips. The microneedles array was fabricated by using deep reactive ion etching (DRIE) and the biodegradable tips were made to be porous by electrochemical etching process. The porous silicon microneedle tips can greatly enhance the transdermal drug delivery in a minimum invasion, painless, and convenient manner, at the same time; they are breakable and biodegradable. Basically, the main problem of the silicon microneedles consists of broken microneedles tips during the insertion. The solution proposed is to fabricate the microneedle tip from a biodegradable material - porous silicon. The silicon microneedles are fabricated using DRIE notching effect of reflected charges on mask. The process overcomes the difficulty in the undercut control of the tips during the classical isotropic silicon etching process. When the silicon tips were formed, the porous tips were then generated using a classical electrochemical anodization process in MeCN/HF/H2O solution. The paper presents the experimental results of in vitro release of calcein and BSA with animal skins using a microneedle array with biodegradable tips. Compared to the transdermal drug delivery without any enhancer, the microneedle array had presented significant enhancement of drug release.

A new method of morphological comparison for bony reconstructive surgery: maxillary reconstruction using scapular tip bone

Science.gov (United States)

Chan, Harley; Gilbert, Ralph W.; Pagedar, Nitin A.; Daly, Michael J.; Irish, Jonathan C.; Siewerdsen, Jeffrey H.

2010-02-01

esthetic appearance is one of the most important factors for reconstructive surgery. The current practice of maxillary reconstruction chooses radial forearm, fibula or iliac rest osteocutaneous to recreate three-dimensional complex structures of the palate and maxilla. However, these bone flaps lack shape similarity to the palate and result in a less satisfactory esthetic. Considering similarity factors and vasculature advantages, reconstructive surgeons recently explored the use of scapular tip myo-osseous free flaps to restore the excised site. We have developed a new method that quantitatively evaluates the morphological similarity of the scapula tip bone and palate based on a diagnostic volumetric computed tomography (CT) image. This quantitative result was further interpreted as a color map that rendered on the surface of a three-dimensional computer model. For surgical planning, this color interpretation could potentially assist the surgeon to maximize the orientation of the bone flaps for best fit of the reconstruction site. With approval from the Research Ethics Board (REB) of the University Health Network, we conducted a retrospective analysis with CT image obtained from 10 patients. Each patient had a CT scans including the maxilla and chest on the same day. Based on this image set, we simulated total, subtotal and hemi palate reconstruction. The procedure of simulation included volume segmentation, conversing the segmented volume to a stereo lithography (STL) model, manual registration, computation of minimum geometric distances and curvature between STL model. Across the 10 patients data, we found the overall root-mean-square (RMS) conformance was 3.71+/- 0.16 mm

Crack tip stress and strain

International Nuclear Information System (INIS)

Francois, D.

1975-01-01

The study of potential energy variations in a loaded elastic solid containing a crack leads to determination of the crack driving force G. Generalization of this concept to cases other than linear elasticity leads to definition of the integral J. In a linear solid, the crack tip stress field is characterized by a single parameter: the stress-intensity factor K. When the crack tip plastic zone size is confined to the elastic singularity J=G, it is possible to establish relationship between these parameters and plastic strain (and in particular the crack tip opening displacement delta). The stress increases because of the triaxiality effect. This overload rises with increasing strain hardening. When the plastic zone size expands, using certain hypotheses, delta can be calculated. The plastic strain intensity is exclusively dependent on parameter J [fr

Phonon Transport through Nanoscale Contact in Tip-Based Thermal Analysis of Nanomaterials.

Science.gov (United States)

Dulhani, Jay; Lee, Bong Jae

2017-07-28

Nanomaterials have been actively employed in various applications for energy and sustainability, such as biosensing, gas sensing, solar thermal energy conversion, passive radiative cooling, etc. Understanding thermal transports inside such nanomaterials is crucial for optimizing their performance for different applications. In order to probe the thermal transport inside nanomaterials or nanostructures, tip-based nanoscale thermometry has often been employed. It has been well known that phonon transport in nanometer scale is fundamentally different from that occurred in macroscale. Therefore, Fourier's law that relies on the diffusion approximation is not ideally suitable for describing the phonon transport occurred in nanostructures and/or through nanoscale contact. In the present study, the gray Boltzmann transport equation (BTE) is numerically solved using finite volume method. Based on the gray BTE, phonon transport through the constriction formed by a probe itself as well as the nanoscale contact between the probe tip and the specimen is investigated. The interaction of a probe and a specimen (i.e., treated as a substrate) is explored qualitatively by analyzing the temperature variation in the tip-substrate configuration. Besides, each contribution of a probe tip, tip-substrate interface, and a substrate to the thermal resistance are analyzed for wide ranges of the constriction ratio of the probe.

Direct Fabrication of Carbon Nanotubes STM Tips by Liquid Catalyst-Assisted Microwave Plasma-Enhanced Chemical Vapor Deposition

Directory of Open Access Journals (Sweden)

Fa-Kuei Tung

2009-01-01

Full Text Available Direct and facile method to make carbon nanotube (CNT tips for scanning tunneling microscopy (STM is presented. Cobalt (Co particles, as catalysts, are electrochemically deposited on the apex of tungsten (W STM tip for CNT growth. It is found that the quantity of Co particles is well controlled by applied DC voltage, concentration of catalyst solution, and deposition time. Using optimum growth condition, CNTs are successfully synthesized on the tip apex by catalyst-assisted microwave-enhanced chemical vapor deposition (CA-MPECVD. A HOPG surface is clearly observed at an atomic scale using the present CNT-STM tip.

The Amazon Monopoly: Is Amazon’s Private Label Business the Tipping Point?

OpenAIRE

Faherty, Emily; Huang, Kevin; Land, Robert

2017-01-01

The purpose of this paper is to consider if Amazon’s increase in private label brands is the tipping point for transforming the e-commerce giant into a monopoly. To lay the foundation, we initially explore the culture, leadership, and business practices which are unique to Amazon that enabled the company to become one of the U.S.’s largest and fastest growing e-commerce websites. Introduced in 2009, Amazon’s private label business has further propelled Amazon’s growth while creating a competi...

Early warning of climate tipping points from critical slowing down: comparing methods to improve robustness

Science.gov (United States)

Lenton, T. M.; Livina, V. N.; Dakos, V.; Van Nes, E. H.; Scheffer, M.

2012-01-01

We address whether robust early warning signals can, in principle, be provided before a climate tipping point is reached, focusing on methods that seek to detect critical slowing down as a precursor of bifurcation. As a test bed, six previously analysed datasets are reconsidered, three palaeoclimate records approaching abrupt transitions at the end of the last ice age and three models of varying complexity forced through a collapse of the Atlantic thermohaline circulation. Approaches based on examining the lag-1 autocorrelation function or on detrended fluctuation analysis are applied together and compared. The effects of aggregating the data, detrending method, sliding window length and filtering bandwidth are examined. Robust indicators of critical slowing down are found prior to the abrupt warming event at the end of the Younger Dryas, but the indicators are less clear prior to the Bølling-Allerød warming, or glacial termination in Antarctica. Early warnings of thermohaline circulation collapse can be masked by inter-annual variability driven by atmospheric dynamics. However, rapidly decaying modes can be successfully filtered out by using a long bandwidth or by aggregating data. The two methods have complementary strengths and weaknesses and we recommend applying them together to improve the robustness of early warnings. PMID:22291229

Palliative treatment of TIPS to portal vein tumor thrombosis complicated with portal vein hypertension

International Nuclear Information System (INIS)

Jiang Zaibo; Shan Hong; Guan Shouhai; Zhu Kangshun; Huang Mingsheng; Li Zhengran; Guo Tiansheng; Liu Lang

2002-01-01

Objective: To evaluate the palliative therapeutic effects of transjugular intrahepatic portosystemic shunt (TIPS) in portal vein tumor thrombosis (PVTT) complicated with portal vein hypertension, and to discuss the technical skills. Methods: There were 14 cases of end-stage hepatocellular carcinoma complicated with PVTT and portal vein hypertension, the average age was 53.6 yr. There were 8 cases with complete occlusion of main portal vein, 6 eases with incomplete thrombosis, and 5 cases combined with portal vein cavernous transformation. One case had simple hemorrhage, 3 eases had intractable ascites, and 10 cases had hemorrhage accompanied by intractable ascites. Results: The procedure of TIPS was successful in 10 cases, the successful rate was about 71%. The mean portal vein pressure was reduced from 37.2 mm Hg to 18.2 mm Hg, with an average reduction of 19.0 mm Hg. After the procedure of TIPS, the ascites decreased, hemorrhage stopped and the clinical symptoms disappeared. The average survival period was 132.3 days. The procedure were failing in 4 cases. Conclusion: TIPS was an effective palliative therapeutic methods to control the hemorrhage and ascites aroused by hepatic carcinoma complicated with PVTT

Determination of lactic microflora of kefir grains and kefir beverage by using culture-dependent and culture-independent methods.

Science.gov (United States)

Kesmen, Zülal; Kacmaz, Nazife

2011-01-01

In this study, we investigated the bacterial compositions of kefir grains and kefir beverages collected from different regions of Turkey by using culture-independent and culture-dependent methods. In the culture-independent detection, 10 different species of bacteria were detected in total by using the polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis of the 16S rRNA gene V3 region. Among these species, Lactobacillus kefiranofaciens was the most dominant one in the kefir grains, while Lactococcus lactis was found to be significantly prevalent in the kefir beverages. In the culture-dependent detection, the primary differentiation and grouping of the isolates from kefir beverages and kefir grains were performed using repetitive sequence-based PCR (rep-PCR) fingerprinting, and the results were validated by 16S rDNA full-length sequencing. According to the results of culture-dependent methods, the most frequently isolated species were L. lactis, Leuconostoc mesenteroides, and Lactobacillus kefiri, respectively. Only 3 species, which are L. lactis, Lactobacillus acidophilus, and Streptococcus thermophilus, were detected with both culture-dependent and culture-independent methods. This study showed that the combination of both methods is necessary for a detailed and reliable investigation of microbial communities in kefir grains and kefir beverages. Due to their artisan- and region-dependent microflora, kefir products can be a source of interesting lactic acid bacteria, either new taxa or strains with specific functional properties, which might be used for the development of new starter cultures and innovative food products. Therefore, an increasing demand exists for new strains that show desirable effects on the product characteristics Artisan dairy products are a candidate source of such microorganisms. For this reason, in this study, the bacterial compositions of kefir grains and kefir beverages obtained from

An Evaluation Method for Team Competencies to Enhance Nuclear Safety Culture

International Nuclear Information System (INIS)

Hang, S. M.; Seong, P. H.; Kim, A. R.

2016-01-01

Safety culture has received attention in safety-critical industries, including nuclear power plants (NPPs), due to various prominent accidents such as concealment of a Station Blackout (SBO) of Kori NPP unit 1 in 2012, the Sewol ferry accident in 2014, and the Chernobyl accident in 1986. Analysis reports have pointed out that one of the major contributors to the cause of the accidents is ‘the lack of safety culture’. The term, nuclear safety culture, was firstly defined after the Chernobyl accident by the IAEA in INSAG report no. 4, as follows “Safety culture is that assembly of characteristics and attitudes in organizations and individuals which establishes that, as an overriding priority, nuclear plant safety issues receive the attention warranted their significance.” Afterwards, a wide consensus grew among researchers and nuclear-related organizations, that safety culture should be evaluated and managed in a certain manner. Consequently, each nuclear-related organization defined and developed their own safety culture definitions and assessment methods. However, none of these methods provides a way for an individual or a team to enhance the safety culture of an organization. Especially for a team, which is the smallest working unit in NPPs, team members easily overlook their required practices to improve nuclear safety culture. Therefore in this study, we suggested a method to estimate nuclear safety culture of a team, by approaching with the ‘competency’ point of view. The competency is commonly focused on individuals, and defined as, “underlying characteristics of an individual that are causally related to effective or superior performance in a job.” Similar to safety culture, the definition of competency focuses on characteristics and attitudes of individuals. Thus, we defined ‘safety culture competency’ as “underlying characteristics and outward attitudes of individuals that are causally related to a healthy and strong nuclear safety

Optical shaping of a nano-scale tip by femtosecond laser assisted field evaporation

Science.gov (United States)

Di Russo, E.; Houard, J.; Langolff, V.; Moldovan, S.; Rigutti, L.; Deconihout, B.; Blavette, D.; Bogdanowicz, J.; Vella, A.

2018-04-01

We have investigated the morphology of a nanotip under femtosecond laser pulse illumination and a high electric field. We show that both the symmetry and the local radius of the tip change with the direction of laser polarization as against the tip axis. The experiments were performed on the very same GaN nanotip by laser-assisted atom probe tomography and electron tomography. This allowed an accurate assessment of the tip features by following the order of evaporation of single atoms from the surface. A change of atom emission sites was observed when a change of the angle between the tip axis and the linearly polarized electric field of the laser was imposed. This enables an optical control of field-evaporation sites. A close optical control of the tip morphology on a scale below 10 nm is thus achievable. Calculations of the field at nanotip apex and absorption maps support the experimental observations. Based on the present study, methods can be developed for reshaping nanotips at the nanometer level. This finding opens perspectives for numerous applications, making use of nanotips as probes or field emitters, and for plasmonic devices.

Twelve Tips for Effective Electronic Presentation.

Science.gov (United States)

Crosby, Joy

1994-01-01

Offers 12 tips for effective electronic presentation. This article is intended for readers who may be considering using electronic presentation for the first time. Offers reasons for its popularity and occasions when it may be used. The tips offer assistance in the design and presentation of electronic material. (LZ)

Reduction of TIP30 in esophageal squamous cell carcinoma cells involves promoter methylation and microRNA-10b

Energy Technology Data Exchange (ETDEWEB)

Dong, Wenjie, E-mail: dongwenjie200581@126.com [Department of Internal Medicine-Oncology, The First Affiliated Hospital, Zhengzhou University (China); Shen, Ruizhe; Cheng, Shidan [Department of Gastroenterology, Rui-jin Hospital, Shanghai Jiao Tong University, Shanghai (China)

2014-10-31

Highlights: • TIP30 expression is frequently suppressed in ESCC. • TIP30 was hypermethylated in ESCC. • Reduction of TIP30 was significantly correlated with LN metastasis. • miR-10b is a direct regulator of TIP30. - Abstract: TIP30 is a putative tumor suppressor that can promote apoptosis and inhibit angiogenesis. However, the role of TIP30 in esophageal squamous cell carcinoma (ESCC) biology has not been investigated. Immunohistochemistry was used to investigate the expression of TIP30 in 70 ESCC. Hypermethylation of TIP30 was evaluated by the methylation specific PCR (MSP) method in ESCC (tumor and paired adjacent non-tumor tissues). Lost expression of TIP30 was observed in 50 of 70 (71.4%) ESCC. 61.4% (43 of 70) of primary tumors analyzed displayed TIP30 hypermethylation, indicating that this aberrant characteristic is common in ESCC. Moreover, a statistically significant inverse association was found between TIP30 methylation status and expression of the TIP30 protein in tumor tissues (p = 0.001). We also found that microRNA-10b (miR-10b) targets a homologous DNA region in the 3′untranslated region of the TIP30 gene and represses its expression at the transcriptional level. Reporter assay with 3′UTR of TIP30 cloned downstream of the luciferase gene showed reduced luciferase activity in the presence of miR-10b, providing strong evidence that miR-10b is a direct regulator of TIP30. These results suggest that TIP30 expression is regulated by promoter methylation and miR-10b in ESCC.

Low Vision Tips

Science.gov (United States)

... this page: https://medlineplus.gov/lowvision.html MedlinePlus: Low Vision Tips We are sorry. MedlinePlus no longer maintains the For Low Vision Users page. You will still find health resources ...

Tips, Tropes, and Trivia: Ideas for Teaching Educational Research.

Science.gov (United States)

Stallings, William M.; And Others

The collective experience of more than 50 years has led to the development of approaches that have enhanced student comprehension in the teaching of educational research methods, statistics, and measurement. Tips for teachers include using illustrative problems with one-digit numbers, using common situations and everyday objects to illustrate…

URANS simulations of the tip-leakage cavitating flow with verification and validation procedures

Science.gov (United States)

Cheng, Huai-yu; Long, Xin-ping; Liang, Yun-zhi; Long, Yun; Ji, Bin

2018-04-01

In the present paper, the Vortex Identified Zwart-Gerber-Belamri (VIZGB) cavitation model coupled with the SST-CC turbulence model is used to investigate the unsteady tip-leakage cavitating flow induced by a NACA0009 hydrofoil. A qualitative comparison between the numerical and experimental results is made. In order to quantitatively evaluate the reliability of the numerical data, the verification and validation (V&V) procedures are used in the present paper. Errors of numerical results are estimated with seven error estimators based on the Richardson extrapolation method. It is shown that though a strict validation cannot be achieved, a reasonable prediction of the gross characteristics of the tip-leakage cavitating flow can be obtained. Based on the numerical results, the influence of the cavitation on the tip-leakage vortex (TLV) is discussed, which indicates that the cavitation accelerates the fusion of the TLV and the tip-separation vortex (TSV). Moreover, the trajectory of the TLV, when the cavitation occurs, is close to the side wall.

Cross-cultural communication: Tools for working with families and children.

Science.gov (United States)

Ladha, Tehseen; Zubairi, Mohammad; Hunter, Andrea; Audcent, Tobey; Johnstone, Julie

2018-02-01

The ability to communicate effectively with patients and families is paramount for good patient care. This practice point reviews the importance of communicating effectively in cross-cultural encounters. The concept of cultural competence is introduced, along with the LEARN (Listen, Explain, Acknowledge, Recommend, Negotiate) model for cross-cultural communication. Three vignettes, one each in Indigenous, global, and newcomer child health, are used to illustrate challenges in cross-cultural communication and effective application of the LEARN model. Practical tips are provided for communicating across cultures.

Improved recovery of cryotherapy-treated shoot tips following thermotherapy of in vitro-grown stock shoots of raspberry (Rubus idaeus L.).

Science.gov (United States)

Wang, Qiaochun; Valkonen, Jari P T

2009-01-01

Raspberry bushy dwarf virus (RBDV) can be efficiently eradicated from raspberry plants (Rubus idaeus) by a procedure combining thermotherapy and cryotherapy. However, the bottleneck of this procedure is that, following thermotherapy, cryopreserved shoot tips become chlorotic during regrowth and eventually die after several subcultures. In addition, survival of heat-treated stock shoots and recovery of cryopreserved shoot tips following thermotherapy are low. The present study focused towards improving regrowth of cryopreserved raspberry shoot tips following thermotherapy. Results showed that preconditioning stock shoots with salicylic acid (SA; 0.01-0.1 mM) markedly increased survival of stock shoots after 4 weeks of thermotherapy. Regrowth of cryopreserved shoot tips following thermotherapy was also significantly enhanced when SA (0.05-0.1 mM) was used for preconditioning stock shoots. Addition of either Fe-ethylenediaminetetracetic acid (Fe-EDTA, 50 mg per L) or Fe-ethylenediaminedi(o)hydroxyphenylacetic acid (Fe-EDDHA, 50 mg per L) to post-culture medium strongly promoted regrowth and totally prevented chlorosis of shoots regenerated from cryopreserved shoot tips following thermotherapy. Using the parameters optimized in the present study, about 80 percent survival of heat-treated stock shoots and about 33 percent regrowth of cryopreserved shoot tips following thermotherapy were obtained. Morphology of plants regenerated from cryopreserved shoot tips following thermotherapy was identical to that of control plants, based on observations of leaf shape and size, internode length and plant height. Optimization of the thermotherapy procedure followed by cryotherapy will facilitate the wider application of this technique to eliminate viruses which can invade meristems.

Bent versus straight tips in micropulsed longitudinal phacoemulsification.

Science.gov (United States)

Stagg, Brian C; Gupta, Isha; Cahoon, Judd; Ronquillo, Cecinio; Shi, Dallas; Zaugg, Brian; Gardiner, Gareth; Barlow, William R; Pettey, Jeff H; Aabid Farukhi, M; Jensen, Jason; Olson, Randall J

2015-10-01

The aim of this study was to evaluate bent and straight phacoemulsification tips to determine which tip is more efficient in removal of lens fragments, using micropulsed longitudinal ultrasound in phacoemulsification. In vitro laboratory study. The John A. Moran Eye Center Laboratories, University of Utah, Salt Lake City, Utah, was the study setting. Pig lenses hardened in a manner comparable with dense human cataracts were cut into 2-mm cubes and removed with micropulsed longitudinal ultrasound using settings previously shown to be optimally efficient (6 milliseconds on and 6 milliseconds off for a bent tip). To verify this time as most efficient for a straight tip, we also tested times of 5, 6, and 7 milliseconds time on and off. The tips were either straight or with a 20-degree bend. Twenty cubes were used for each comparative run. For the straight tip, 6 milliseconds on (1.56 ± 0.815 seconds) was significantly more efficient than 7 milliseconds on (2.45 ± 1.56 seconds, p = 0.001) and not significantly more efficient than 5 milliseconds on (1.69 ± 0.86 seconds, p = 0.43). Five milliseconds off time (1.45 ± 0.76s) was more efficient than 6 milliseconds (2.06 ± 1.37 seconds, p = 0.004) and 7 milliseconds off (2.18 ± 1.24s, p = 0.001). The straight tip was more efficient than the bent tip (1.38 ± 0.83 versus 2.93 ± 2.14 seconds, p = 0.006). Results are contrary to accepted common belief. Micropulsed longitudinal phacoemulsification is more efficient with a straight rather than a bent tip. Copyright © 2015 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved.

Study on unsteady tip leakage vortex cavitation in an axial-flow pump using an improved filter-based model

Energy Technology Data Exchange (ETDEWEB)

Zhang, Desheng; Shi, Lei; Zhao, Ruijie; Shi, Weidong; Pan, Qiang [Jiangsu University, Zhenjiang (China); Esch, B. P. [Eindhoven University of Technology, Eindhoven (Netherlands)

2017-02-15

The aim of the present investigation is to simulate and analyze the tip leakage flow structure and instantaneous evolution of tip vortex cavitation in a scaled axial-flow pump model. The improved filter-based turbulence model based on the density correction and a homogeneous cavitation model were used for implementing this work. The results show that when entering into the tip clearance, the backward flow separates from the blade tip near the pressure side, resulting in the generation of a corner vortex with high magnitude of turbulence kinetic energy. Then, at the exit of the tip clearance, the leakage jets would re-attach on the blade tip wall. Moreover, the maximum swirling strength method was employed in identifying the TLV core and a counter-rotating induced vortex near the end-wall successfully. The three dimensional cavitation patterns and in-plain cavitation structures obtained by the improved numerical method agree well with the experimental results. At the sheet cavitation trailing edge in the tip region, the perpendicular cavitation cloud induced by TLV sheds and migrates toward the pressure side of the neighboring blade. During its migration, it breaks down abruptly and generates a large number of smallscale cavities, leading to severe degradation of the pump performance, which is similar with the phenomenon observed by Tan et al.

Tips for Reducing Pesticide Impacts on Wildlife

Science.gov (United States)

This Web page provides tips for pesticide users in residential and agricultural settings, as well as tips for certified pesticide applicators for ways to protect wildlife from potentially harmful effects of pesticides.

Cloning higher plants from aseptically cultured tissues and cells

Science.gov (United States)

Krikorian, A. D.

1982-01-01

A review of aseptic culture methods for higher plants is presented, which focuses on the existing problems that limit or prevent the full realization of cloning plants from free cells. It is shown that substantial progress in clonal multiplication has been made with explanted stem tips or lateral buds which can be stimulated to produce numerous precocious axillary branches. These branches can then be separated or subdivided and induced to root in order to yield populations of genetically and phenotypically uniorm plantlets. Similarly, undifferentiated calluses can sometimes be induced to form shoots and/or roots adventitiously. Although the cell culture techniques required to produce somatic embryos are presently rudimentary, steady advances are being made in learning how to stimulate formation of somatic or adventive embryos from totipotent cells grown in suspension cultures. It is concluded that many problems exist in the producing and growing of totipotent or morphogenetically competent cell suspensions, but the potential benefits are great.

Surface tension-induced high aspect-ratio PDMS micropillars with concave and convex lens tips

KAUST Repository

Li, Huawei; Fan, Yiqiang; Yi, Ying; Foulds, Ian G.

2013-01-01

This paper reports a novel method for the fabrication of 3-dimensional (3D) Polydimethylsiloxane (PDMS) micropillars with concave and convex lens tips in a one-step molding process, using a CO2 laser-machined Poly(methyl methacrylate) (PMMA) mold with through holes. The PDMS micropillars are 4 mm high and have an aspect ratio of 251. The micropillars are formed by capillary force drawing up PDMS into the through hole mold. The concave and convex lens tips of the PDMS cylindrical micropillars are induced by surface tension and are controllable by changing the surface wetting properties of the through holes in the PMMA mold. This technique eliminates the requirements of expensive and complicated facilities to prepare a 3D mold, and it provides a simple and rapid method to fabricate 3D PDMS micropillars with controllable dimensions and tip shapes. © 2013 IEEE.

Surface tension-induced high aspect-ratio PDMS micropillars with concave and convex lens tips

KAUST Repository

Li, Huawei

2013-04-01

This paper reports a novel method for the fabrication of 3-dimensional (3D) Polydimethylsiloxane (PDMS) micropillars with concave and convex lens tips in a one-step molding process, using a CO2 laser-machined Poly(methyl methacrylate) (PMMA) mold with through holes. The PDMS micropillars are 4 mm high and have an aspect ratio of 251. The micropillars are formed by capillary force drawing up PDMS into the through hole mold. The concave and convex lens tips of the PDMS cylindrical micropillars are induced by surface tension and are controllable by changing the surface wetting properties of the through holes in the PMMA mold. This technique eliminates the requirements of expensive and complicated facilities to prepare a 3D mold, and it provides a simple and rapid method to fabricate 3D PDMS micropillars with controllable dimensions and tip shapes. © 2013 IEEE.

RESONANCE COMPATIBILITY BETWEEN ENDOSONIC TIPS AND ULTRASONIC DEVICES OF DIFFERENT BRANDS.

Directory of Open Access Journals (Sweden)

Kalin K. Shiyakov

2014-11-01

Full Text Available The aim of the study was to determine the compatibility of 6 piezoelectric scalers - Mini Piezon (EMS, Pyon 2 LED (W&H, Woodpecker HW-3H (GWMI, Varios 550 (NSK, P5 Newtron (Satelec-Acteon and DTE HD-7H (GWMI with 8 types of endosonic tips for separated instruments removal - K-files # 20 and 25 (EMS, ET25 (Satelec, Redo 2 (VDW, CPR-tips 6,7,8 (Obtura Spartan, Proultra Endo tips 6,7,8 (Dentsply-Maillefer, RT3 (EMS, Endo E3 (W&H, E7 (NSK. Methods: Examined and measured was the change in the tips’ displacement amplitude with the power increase of the scalers under total magnification 80x with an optical microscope (Leica MZ6 and an image-measuring software (Klonk Image Measurement. Results: Ultrasonic devices’ compatibility with the examined tips was as follows: Woodpecker – 76,9%, Mini Piezon – 61,5%, Pyon 2 LED - 30,7%, Varios 550 – 83,3%, P5 Newtron – 83,3%, DTE – 33,3%. Lack of compatibility was found in 40,35% of all cases. In 29,82% of the cases of lack of compatibility it was demonstrated as a non-effective vibration, and in the rest of the cases – 10,53% - uncontrolled over-powerful vibration, which was dangerous to use. Conclusion: Endosonic tips should be carefully chosen in accordance with the ultrasonic scaler used.

Establishment of primary bovine intestinal epithelial cell culture and clone method.

Science.gov (United States)

Zhan, Kang; Lin, Miao; Liu, Ming-Mei; Sui, Yang-Nan; Zhao, Guo-Qi

2017-01-01

The aim of this study was to establish bovine intestinal epithelial cell (BIEC) line and provide a novel clone cell method. Although various strategies of bovine cell culture and clone techniques have been reported, these methods remain not established. Here, we culture successfully primary BIECs and establish a novel clone cell method. Our result showed that BIECs could be successfully cultured and passaged about generation 5. These cellular aggregates and clusters were adherent loosely at day 2 of culture. Cell aggregates and clusters start to proliferate after approximately 4 d. The BIECs showed positive reaction against cytokeratin 18, E-cadherin, and characteristics of epithelial-like morphology. In addition, the fatty acid-binding proteins (FABPs), villin, and intestinal peptidase (IP) band were positive in BIECs. Our results suggest that the establishment of culturing and clone BIEC methods will apply to isolate and clone other primary cells. These BIECs could therefore contribute to the study of bovine intestinal nutrient absorption and regulation, immune regulation, and the pathogenesis of the bovine intestinal disease, which will provide intestinal cell model in vitro.

Dependence of electric field on STM tip preparation

DEFF Research Database (Denmark)

Huang, D.H.; Grey, Francois; Aono, M.

1998-01-01

Voltage pulses applied between an STM tip and a surface can modify the surface on the nanometer scale due to electric-field-induced evaporation. However, at present, different groups have achieved surface modification with quite different bias conditions, and it is still difficult to obtain high...... reproducibility in such experiments. In this paper, we measure the tip displacement during a pulse at constant tunnelling current, and deduce that the electric field produced by the pulse depends in a systematic way on tip preparation, The results show how differences in tip preparation can be a major source...

Mutual inductance instability of the tip vortices behind a wind turbine

DEFF Research Database (Denmark)

Sarmast, Sasan; Dadfar, Reza; Mikkelsen, Robert Flemming

2014-01-01

Two modal decomposition techniques are employed to analyse the stability of wind turbine wakes. A numerical study on a single wind turbine wake is carried out focusing on the instability onset of the trailing tip vortices shed from the turbine blades. The numerical model is based on large......-eddy simulations (LES) of the Navier–Stokes equations using the actuator line (ACL) method to simulate the wake behind the Tjæreborg wind turbine. The wake is perturbed by low-amplitude excitation sources located in the neighbourhood of the tip spirals. The amplification of the waves travelling along the spiral...

Relocalization of human chromatin remodeling cofactor TIP48 in mitosis

International Nuclear Information System (INIS)

Sigala, Barbara; Edwards, Mina; Puri, Teena; Tsaneva, Irina R.

2005-01-01

TIP48 is a highly conserved eukaryotic AAA + protein which is an essential cofactor for several complexes involved in chromatin acetylation and remodeling, transcriptional and developmental regulation and nucleolar organization and trafficking. We show that TIP48 abundance in HeLa cells did not change during the cell cycle, nor did its distribution in various biochemical fractions. However, we observed distinct changes in the subcellular localization of TIP48 during M phase using immunofluorescence microscopy. Our studies demonstrate that in interphase cells TIP48 was found mainly in the nucleus and exhibited a distinct localization in the nuclear periphery. As the cells entered mitosis, TIP48 was excluded from the condensing chromosomes but showed association with the mitotic apparatus. During anaphase, some TIP48 was detected in the centrosome colocalizing with tubulin but the strongest staining appeared in the mitotic equator associated with the midzone central spindle. Accumulation of TIP48 in the midzone and the midbody was observed in late telophase and cytokinesis. This redeployment of TIP48 during anaphase and cytokinesis was independent of microtubule assembly. The relocation of endogenous TIP48 to the midzone/midbody under physiological conditions suggests a novel and distinct function for TIP48 in mitosis and possible involvement in the exit of mitosis

Angle-tip Fiber Probe as Humidity Sensor

Directory of Open Access Journals (Sweden)

Pabitra NATH

2010-05-01

Full Text Available In this paper, I present a simple fiber optic relative humidity sensor (FORHS using an angled-tip multimode optical fiber. The sensing region is fabricated by coating moisture sensitive Cobalt Chloride (CoCl2 doped polyvinyl alcohol (PVA film on the surface of fiber optic tip. Light signal introducing from flat-end of the fiber is back-reflected at the fiber tip-air interface by the effect of total internal refection. The change of relative humidity (RH in the outstanding medium affects of evanescent field absorption at the fiber tip-sensing film interface thus, modulates the back-reflected signal. With the present sensing investigation, RH ranging from 5 % to 95 % can be measured with high degree of repeatability and has a fast response time of about 2 seconds.

Culture methods of allograft musculoskeletal tissue samples in Australian bacteriology laboratories.

Science.gov (United States)

Varettas, Kerry

2013-12-01

Samples of allograft musculoskeletal tissue are cultured by bacteriology laboratories to determine the presence of bacteria and fungi. In Australia, this testing is performed by 6 TGA-licensed clinical bacteriology laboratories with samples received from 10 tissue banks. Culture methods of swab and tissue samples employ a combination of solid agar and/or broth media to enhance micro-organism growth and maximise recovery. All six Australian laboratories receive Amies transport swabs and, except for one laboratory, a corresponding biopsy sample for testing. Three of the 6 laboratories culture at least one allograft sample directly onto solid agar. Only one laboratory did not use a broth culture for any sample received. An international literature review found that a similar combination of musculoskeletal tissue samples were cultured onto solid agar and/or broth media. Although variations of allograft musculoskeletal tissue samples, culture media and methods are used in Australian and international bacteriology laboratories, validation studies and method evaluations have challenged and supported their use in recovering fungi and aerobic and anaerobic bacteria.

Tapered optical fiber tip probes based on focused ion beam-milled Fabry-Perot microcavities

Science.gov (United States)

André, Ricardo M.; Warren-Smith, Stephen C.; Becker, Martin; Dellith, Jan; Rothhardt, Manfred; Zibaii, M. I.; Latifi, H.; Marques, Manuel B.; Bartelt, Hartmut; Frazão, Orlando

2016-09-01

Focused ion beam technology is combined with dynamic chemical etching to create microcavities in tapered optical fiber tips, resulting in fiber probes for temperature and refractive index sensing. Dynamic chemical etching uses hydrofluoric acid and a syringe pump to etch standard optical fibers into cone structures called tapered fiber tips where the length, shape, and cone angle can be precisely controlled. On these tips, focused ion beam is used to mill several different types of Fabry-Perot microcavities. Two main cavity types are initially compared and then combined to form a third, complex cavity structure. In the first case, a gap is milled on the tapered fiber tip which allows the external medium to penetrate the light guiding region and thus presents sensitivity to external refractive index changes. In the second, two slots that function as mirrors are milled on the tip creating a silica cavity that is only sensitive to temperature changes. Finally, both cavities are combined on a single tapered fiber tip, resulting in a multi-cavity structure capable of discriminating between temperature and refractive index variations. This dual characterization is performed with the aid of a fast Fourier transform method to separate the contributions of each cavity and thus of temperature and refractive index. Ultimately, a tapered optical fiber tip probe with sub-standard dimensions containing a multi-cavity structure is projected, fabricated, characterized and applied as a sensing element for simultaneous temperature and refractive index discrimination.

Rhodamine B induces long nucleoplasmic bridges and other nuclear anomalies in Allium cepa root tip cells.

Science.gov (United States)

Tan, Dehong; Bai, Bing; Jiang, Donghua; Shi, Lin; Cheng, Shunchang; Tao, Dongbing; Ji, Shujuan

2014-03-01

The cytogenetic toxicity of rhodamine B on root tip cells of Allium cepa was investigated. A. cepa were cultured in water (negative control), 10 ppm methyl methanesulfonate (positive control), and three concentrations of rhodamine B (200, 100, and 50 ppm) for 7 days. Rhodamine B inhibited mitotic activity; increased nuclear anomalies, including micronuclei, nuclear buds, and bridged nuclei; and induced oxidative stress in A. cepa root tissues. Furthermore, a substantial amount of long nucleoplasmic bridges were entangled together, and some nuclei were simultaneously linked to several other nuclei and to nuclear buds with nucleoplasmic bridges in rhodamine B-treated cells. In conclusion, rhodamine B induced cytogenetic effects in A. cepa root tip cells, which suggests that the A. cepa root is an ideal model system for detecting cellular interactions.

Comparison of the lysis centrifugation method with the conventional blood culture method in cases of sepsis in a tertiary care hospital.

Science.gov (United States)

Parikh, Harshal R; De, Anuradha S; Baveja, Sujata M

2012-07-01

Physicians and microbiologists have long recognized that the presence of living microorganisms in the blood of a patient carries with it considerable morbidity and mortality. Hence, blood cultures have become critically important and frequently performed test in clinical microbiology laboratories for diagnosis of sepsis. To compare the conventional blood culture method with the lysis centrifugation method in cases of sepsis. Two hundred nonduplicate blood cultures from cases of sepsis were analyzed using two blood culture methods concurrently for recovery of bacteria from patients diagnosed clinically with sepsis - the conventional blood culture method using trypticase soy broth and the lysis centrifugation method using saponin by centrifuging at 3000 g for 30 minutes. Overall bacteria recovered from 200 blood cultures were 17.5%. The conventional blood culture method had a higher yield of organisms, especially Gram positive cocci. The lysis centrifugation method was comparable with the former method with respect to Gram negative bacilli. The sensitivity of lysis centrifugation method in comparison to conventional blood culture method was 49.75% in this study, specificity was 98.21% and diagnostic accuracy was 89.5%. In almost every instance, the time required for detection of the growth was earlier by lysis centrifugation method, which was statistically significant. Contamination by lysis centrifugation was minimal, while that by conventional method was high. Time to growth by the lysis centrifugation method was highly significant (P value 0.000) as compared to time to growth by the conventional blood culture method. For the diagnosis of sepsis, combination of the lysis centrifugation method and the conventional blood culture method with trypticase soy broth or biphasic media is advocable, in order to achieve faster recovery and a better yield of microorganisms.

The Tipping Points of Technology Development

Directory of Open Access Journals (Sweden)

Tauno Kekäle

2014-07-01

Full Text Available The tipping point, the decisive point in time in the competition between old and new, is an interesting phenomenon in physics of today. This aspect in technology acceptance is connected to many business decisions such as technology investments, product releases, resource allocation, sales forecasts and, ultimately, affects the profitability and even survival of a company. The tipping point itself is based on many stochastic and dynamic variables, and the process may at least partly be described as path-dependent. This paper analyses the tipping point from three aspects: (1 product performance, (2 features of the market and infrastructure (including related technologies and human network externalities, and (3 actions of the incumbents (including customer lock-in, systems lock-in, and sustaining innovation. The paper is based on the Bass s-curve idea and the technology trajectory concept proposed by Dosi. Three illustrative cases are presented to make the point of the multiple factors affecting technology acceptance and, thus, the tipping point. The paper also suggests outlines for further research in field of computer simulation.

Final Technical Report: Electrohydrodynamic Tip Streaming

Energy Technology Data Exchange (ETDEWEB)

Basaran, Osman [Purdue Univ., West Lafayette, IN (United States)

2016-01-06

When subjected to strong electric fields, liquid drops and films form conical tips and emit thin jets from their tips. Such electrodydrodynamic (EDH) tip streaming or cone-jetting phenomena, which are sometimes referred to as electrospraying, occur widely in nature, e.g., in ejection of streams of small charged drops from pointed tips of raindrops in thunderclouds, and technology, e.g., in electrospray mass spectrometry or electric field-driven solvent extraction. More recently, EHD cone-jetting has emerged as a powerful technique for direct printing of solar cells, micro- and nano- particle production, and microencapsulation for controlled release. In many of the aforementioned situations, of equal importance to the processes by which one drop disintegrates to form several drops are those by which (a) two drops come together and coalesce and (b) two drops are coupled to form a double droplet system (DDS) or a capillary switch (CS). the main objective of this research program is to advance through simulation, theory, and experiment the breakup, coalescence, and oscillatory dynamics of single and pairs of charged as well as uncharged drops.

Investigation of Legionella Contamination in Bath Water Samples by Culture, Amoebic Co-Culture, and Real-Time Quantitative PCR Methods.

Science.gov (United States)

Edagawa, Akiko; Kimura, Akio; Kawabuchi-Kurata, Takako; Adachi, Shinichi; Furuhata, Katsunori; Miyamoto, Hiroshi

2015-10-19

We investigated Legionella contamination in bath water samples, collected from 68 bathing facilities in Japan, by culture, culture with amoebic co-culture, real-time quantitative PCR (qPCR), and real-time qPCR with amoebic co-culture. Using the conventional culture method, Legionella pneumophila was detected in 11 samples (11/68, 16.2%). Contrary to our expectation, the culture method with the amoebic co-culture technique did not increase the detection rate of Legionella (4/68, 5.9%). In contrast, a combination of the amoebic co-culture technique followed by qPCR successfully increased the detection rate (57/68, 83.8%) compared with real-time qPCR alone (46/68, 67.6%). Using real-time qPCR after culture with amoebic co-culture, more than 10-fold higher bacterial numbers were observed in 30 samples (30/68, 44.1%) compared with the same samples without co-culture. On the other hand, higher bacterial numbers were not observed after propagation by amoebae in 32 samples (32/68, 47.1%). Legionella was not detected in the remaining six samples (6/68, 8.8%), irrespective of the method. These results suggest that application of the amoebic co-culture technique prior to real-time qPCR may be useful for the sensitive detection of Legionella from bath water samples. Furthermore, a combination of amoebic co-culture and real-time qPCR might be useful to detect viable and virulent Legionella because their ability to invade and multiply within free-living amoebae is considered to correlate with their pathogenicity for humans. This is the first report evaluating the efficacy of the amoebic co-culture technique for detecting Legionella in bath water samples.

Diabetes: Dental Tips

Science.gov (United States)

Diabetes: Dental Tips For more copies contact: National Institute of Dental and Craniofacial Research National Oral Health Information Clearinghouse ... damage the gum and bone that hold your teeth in place and may lead to painful chewing ...

TEM observations of crack tip: cavity interactions

International Nuclear Information System (INIS)

Horton, J.A.; Ohr, S.M.; Jesser, W.A.

1981-01-01

Crack tip-cavity interactions have been studied by performing room temperature deformation experiments in a transmission electron microscope on ion-irradiated type 316 stainless steel with small helium containing cavities. Slip dislocations emitted from a crack tip cut, sheared, and thereby elongated cavities without a volume enlargement. As the crack tip approached, a cavity volume enlargement occurred. Instead of the cavities continuing to enlarge until they touch, the walls between the cavities fractured. Fracture surface dimples do not correlate in size or density with these enlarged cavities

Root tips moving through soil

Science.gov (United States)

Curlango-Rivera, Gilberto

2011-01-01

Root elongation occurs by the generation of new cells from meristematic tissue within the apical 1–2 mm region of root tips. Therefore penetration of the soil environment is carried out by newly synthesized plant tissue, whose cells are inherently vulnerable to invasion by pathogens. This conundrum, on its face, would seem to reflect an intolerable risk to the successful establishment of root systems needed for plant life. Yet root tip regions housing the meristematic tissues repeatedly have been found to be free of microbial infection and colonization. Even when spore germination, chemotaxis, and/or growth of pathogens are stimulated by signals from the root tip, the underlying root tissue can escape invasion. Recent insights into the functions of root border cells, and the regulation of their production by transient exposure to external signals, may shed light on long-standing observations. PMID:21455030

Regulation of Histone Acetyltransferase TIP60 Function by Histone Deacetylase 3

Science.gov (United States)

Yi, Jingjie; Huang, Xiangyang; Yang, Yuxia; Zhu, Wei-Guo; Gu, Wei; Luo, Jianyuan

2014-01-01

The key member of the MOZ (monocyticleukaemia zinc finger protein), Ybf2/Sas3, Sas2, and TIP60 acetyltransferases family, Tat-interactive protein, 60 kD (TIP60), tightly modulates a wide array of cellular processes, including chromatin remodeling, gene transcription, apoptosis, DNA repair, and cell cycle arrest. The function of TIP60 can be regulated by SIRT1 through deacetylation. Here we found that TIP60 can also be functionally regulated by HDAC3. We identified six lysine residues as its autoacetylation sites. Mutagenesis of these lysines to arginines completely abolishes the autoacetylation of TIP60. Overexpression of HDAC3 increases TIP60 ubiquitination levels. However, unlike SIRT1, HDAC3 increased the half-life of TIP60. Further study found that HDAC3 colocalized with TIP60 both in the nucleus and the cytoplasm, which could be the reason why HDAC3 can stabilize TIP60. The deacetylation of TIP60 by both SIRT1 and HDAC3 reduces apoptosis induced by DNA damage. Knockdown of HDAC3 in cells increased TIP60 acetylation levels and increased apoptosis after DNA damage. Together, our findings provide a better understanding of TIP60 regulation mechanisms, which is a significant basis for further studies of its cellular functions. PMID:25301942

TIPS - anastomose portossistêmica intra-hepática transjugular. Revisão TIPS - transjugular intrahepatic portosystemic shunt. A review

Directory of Open Access Journals (Sweden)

Gerson CARREIRO

2001-01-01

Full Text Available Diversas alternativas terapêuticas têm sido usadas, atualmente, na tentativa de reduzir a mortalidade de pacientes com hipertensão portal que desenvolvem varizes esofagianas. Abordagem de uma dessas alternativas que ainda é de exceção e pouco utilizada em nosso meio - o "shunt" (desvio portossistêmico intra-hepático transjugular - TIPS ("transjugular intrahepatic portasystemic shunt". O TIPS possibilita redução significativa do gradiente de pressão portohepático, uma vez que funciona como um "shunt" portocava látero-lateral, promovendo, dessa forma, descompressão eficiente do sistema portal, reduzindo significativamente o risco de sangramentos. A técnica consiste na inserção percutânea, através da veia jugular interna, de malha metálica através do parênquima hepático, sob controle angiográfico, criando verdadeira comunicação portocava. Bons resultados na utilização do TIPS têm sido atestados em diversos estudos, muito embora bem poucos deles tenham sido controlados e randomizados de modo a concluir que esse procedimento é seguro, eficaz e com boa relação custo-benefício. Dessa forma, buscou-se, nesta revisão, uma análise do estado atual da utilização do TIPS, sua técnica, principais indicações e complicações. O TIPS vem sendo utilizado nos casos de hemorragia digestiva refratária ao tratamento farmacológico e/ou endoscópico, principalmente em pacientes Child-Pugh B e C ou ainda como opção de controle do quadro, servindo como "ponte" para um futuro transplante hepático. Pode-se considerar ainda o tratamento da ascite refratária, da síndrome hepatorrenal e do hidrotórax hepático como promissoras indicações definitivas para a colocação do TIPS. As complicações dessa técnica estão relacionadas, sobretudo, a sua colocação, às conseqüências hemodinâmicas imediatas, como a encefalopatia hepática, e às complicações tardias envolvendo principalmente a oclusão do "stent" (prótese auto

Turbine-blade tip clearance and tip timing measurements using an optical fiber bundle sensor

Science.gov (United States)

Garcia, Iker; Beloki, Josu; Zubia, Joseba; Durana, Gaizka; Aldabaldetreku, Gotzon

2013-04-01

Traditional limitations of capacitive, inductive or discharging probe sensor for tip timing and tip clearance measurements are overcome by reflective intensity modulated optical fiber sensors. This paper presents the signals and results corresponding to a one stage turbine rig which rotor has 146 blades, obtained from a transonic wind-tunnel test. The probe is based on a trifurcated bundle of optical fibers that is mounted on turbine casing. It is composed of a central illuminating fiber that guides the light from a laser to the turbine blade, and two concentric rings of receiving fibers that collect the reflected light. Two photodetectors turn this reflected light signal from the receiving rings into voltage. The electrical signals are acquired and saved by a high-sample-rate oscilloscope. In tip clearance calculations the ratio of the signals provided by each ring of receiving fibers is evaluated and translated into distance. In the case of tip timing measurements, only one of the signals is considered to get the arrival time of the blade. The differences between the real and theoretical arrival times of the blades are used to obtain the deflections amplitude. The system provides the travelling wave spectrum, which presents the average vibration amplitude of the blades at a certain nodal diameter. The reliability of the results in the turbine rig testing facilities suggests the possibility of performing these measurements in real turbines under real working conditions.

Numerical analysis of turbine blade tip treatments

Science.gov (United States)

Gopalaswamy, Nath S.; Whitaker, Kevin W.

1992-01-01

Three-dimensional solutions of the Navier-Stokes equations for a turbine blade with a turning angle of 180 degrees have been computed, including blade tip treatments involving cavities. The geometry approximates a preliminary design for the GGOT (Generic Gas Oxidizer Turbine). The data presented here will be compared with experimental data to be obtained from a linear cascade using original GGOT blades. Results have been computed for a blade with 1 percent clearance, based on chord, and three different cavity sizes. All tests were conducted at a Reynolds number of 4 x 10 exp 7. The grid contains 39,440 points with 10 spanwise planes in the tip clearance region of 5.008E-04 m. Streamline plots and velocity vectors together with velocity divergence plots reveal the general flow behavior in the clearance region. Blade tip temperature calculations suggest placement of a cavity close to the upstream side of the blade tip for reduction of overall blade tip temperature. The solutions do not account for the relative motion between the endwall and the turbine blade. The solutions obtained are generally consistent with previous work done in this area,

Effects of bromine on mitosis in root-tips of Allium cepa

Energy Technology Data Exchange (ETDEWEB)

Chury, J; Slouka, V

1949-01-01

The root-tips of Allium cepa, 1.5-2 cm. long, were exposed to pure bromine vapor for five minutes. The root-tips were then washed for ten minutes in water, and kept in fresh-water at a temperature of 20-24/sup 0/C. Squash preparations were made and stained according to the method of Darlington and La Cour. Bromine acting for five minutes on the root-tips of Allium has a specific effect on the cell nucleus in the resting stage. The effects induced are shown thirty-six hours after treatment by spindle abnormalities in metaphase and anaphase, and result in polyploidy in a large number of cells. Bromine produces chromosome and chromatid fragmentation; the latter may be followed by reunion. The effect of the bromine is cumulative and depends on the time which elapses between treatment and fixation. The cytological effects induced by bromine strongly suggest that it is another specific mutafacient chemical.

A resilience perspective to water risk management: case-study application of the adaptation tipping point method

Science.gov (United States)

Gersonius, Berry; Ashley, Richard; Jeuken, Ad; Nasruddin, Fauzy; Pathirana, Assela; Zevenbergen, Chris

2010-05-01

start the identification and analysis of adaptive strategies at the end of PSIR scheme: impact and examine whether, and for how long, current risk management strategies will continue to be effective under different future conditions. The most noteworthy application of this approach is the adaptation tipping point method. Adaptation tipping points (ATP) are defined as the points where the magnitude of change is such that the current risk management strategy can no longer meet its objectives. In the ATP method, policy objectives, determining aspirational functioning, are taken as the starting point. Also, the current measures to achieve these objectives are described. This is followed by a sensitivity analysis to determine the optimal and critical boundary conditions (state). Lastly, the state is related to pressures in terms of future change. It should be noted that in the ATP method the driver for adopting a new risk management strategy is not future change as such, but rather failing to meet the policy objectives. In the current paper, the ATP method is applied to the case study of an existing stormwater system in Dordrecht (the Netherlands). This application shows the potential of the ATP method to reduce the complexity of implementing a resilience-focused approach to water risk management. It is expected that this will help foster greater practical relevance of resilience as a perspective for the planning of water management structures.

Optical fiber tips for biological applications: From light confinement, biosensing to bioparticles manipulation.

Science.gov (United States)

Paiva, Joana S; Jorge, Pedro A S; Rosa, Carla C; Cunha, João P S

2018-05-01

The tip of an optical fiber has been considered an attractive platform in Biology. The simple cleaved end of an optical fiber can be machined, patterned and/or functionalized, acquiring unique properties enabling the exploitation of novel optical phenomena. Prompted by the constant need to measure and manipulate nanoparticles, the invention of the Scanning Near-field Optical Microscopy (SNOM) triggered the optimization and development of novel fiber tip microfabrication methods. In fact, the fiber tip was soon considered a key element in SNOM by confining light to sufficiently small extensions, challenging the diffraction limit. As result and in consequence of the newly proposed "Lab On Tip" concept, several geometries of fiber tips were applied in three main fields: imaging (in Microscopy/Spectroscopy), biosensors and micromanipulation (Optical Fiber Tweezers, OFTs). These are able to exert forces on microparticles, trap and manipulate them for relevant applications, as biomolecules mechanical study or protein aggregates unfolding. This review presents an overview of the main achievements, most impactful studies and limitations of fiber tip-based configurations within the above three fields, along the past 10 years. OFTs could be in future a valuable tool for studying several cellular phenomena such as neurodegeneration caused by abnormal protein fibrils or manipulating organelles within cells. This could contribute to understand the mechanisms of some diseases or biophenomena, as the axonal growth in neurons. To the best of our knowledge, no other review article has so far provided such a broad view. Despite of the limitations, fiber tips have key roles in Biology/Medicine. Copyright © 2018 Elsevier B.V. All rights reserved.

A new cell primo-culture method for freshwater benthic diatom communities

OpenAIRE

Debenest, Timothée; Silvestre, Jérôme; Coste, Michel; Delmas, François; Pinelli, Eric

2009-01-01

A new cell primo-culture method was developed for the benthic diatom community isolated from biofilm sampled in rivers. The approach comprised three steps: (1) scraping biofilm from river pebbles, (2) diatom isolation from biofilm, and (3) diatom community culture. With a view to designing a method able to stimulate the growth of diatoms, to limit the development of other microorganisms, and to maintain in culture a community similar to the original natural one, different factors were test...

A Comparative Study of Conventional and Tip-Fin Propeller Performance

DEFF Research Database (Denmark)

Andersen, Poul

1997-01-01

During more than a decade several attempts have been made to obtain higher propeller efficiencies by radically modifying the geometry in the tip region of the blade. In the tip-fin propeller a tip fin or winglet is attached to the blade tip and integrated into the blade in such a way that the bla...

The effect of three culture methods on intensive culture system of pacific white shrimp ( Litopenaeus vannamei)

Science.gov (United States)

Ma, Zhen; Wan, Rong; Song, Xiefa; Gao, Lei

2013-09-01

Different culture methods may affect the intensive culture system of Pacific white shrimp ( Litopenaeus vannamei) regarding water quality and growth and economic performance. This study evaluated the potential effects of three culture methods through cultivation of juvenile shrimps under consistent tank management conditions for 84 d. The three methods involved shrimp cultivation in different tanks, i.e., outdoor tanks with cement bottom (mode-C), greenhouse tanks with cement bottom (mode-G) and outdoor tanks with mud-substrate (mode-M). Results showed that water temperature was significantly higher in mode-G than that in mode-C ( P shrimps. In the mid-late period, the average concentrations of TAN, NO2-N, DIP and COD were significantly lower in mode-M and mode-G compared with those in mode-C ( P shrimp weight among different treatments ( P > 0.05), mode-M had significantly higher shrimp yield, survival rate and feed conversion rate ( P < 0.05) than other modes. There were significant differences in revenue and net return among different treatments ( P < 0.05). These demonstrated that the treatments of mode-G and mode-M were conductive to the intensive culture system of L. vannamei.

Investigation of Legionella Contamination in Bath Water Samples by Culture, Amoebic Co-Culture, and Real-Time Quantitative PCR Methods

Directory of Open Access Journals (Sweden)

Akiko Edagawa

2015-10-01

Full Text Available We investigated Legionella contamination in bath water samples, collected from 68 bathing facilities in Japan, by culture, culture with amoebic co-culture, real-time quantitative PCR (qPCR, and real-time qPCR with amoebic co-culture. Using the conventional culture method, Legionella pneumophila was detected in 11 samples (11/68, 16.2%. Contrary to our expectation, the culture method with the amoebic co-culture technique did not increase the detection rate of Legionella (4/68, 5.9%. In contrast, a combination of the amoebic co-culture technique followed by qPCR successfully increased the detection rate (57/68, 83.8% compared with real-time qPCR alone (46/68, 67.6%. Using real-time qPCR after culture with amoebic co-culture, more than 10-fold higher bacterial numbers were observed in 30 samples (30/68, 44.1% compared with the same samples without co-culture. On the other hand, higher bacterial numbers were not observed after propagation by amoebae in 32 samples (32/68, 47.1%. Legionella was not detected in the remaining six samples (6/68, 8.8%, irrespective of the method. These results suggest that application of the amoebic co-culture technique prior to real-time qPCR may be useful for the sensitive detection of Legionella from bath water samples. Furthermore, a combination of amoebic co-culture and real-time qPCR might be useful to detect viable and virulent Legionella because their ability to invade and multiply within free-living amoebae is considered to correlate with their pathogenicity for humans. This is the first report evaluating the efficacy of the amoebic co-culture technique for detecting Legionella in bath water samples.

Structure and stability of semiconductor tip apexes for atomic force microscopy

International Nuclear Information System (INIS)

Pou, P; Perez, R; Ghasemi, S A; Goedecker, S; Jelinek, P; Lenosky, T

2009-01-01

The short range force between the tip and the surface atoms, that is responsible for atomic-scale contrast in atomic force microscopy (AFM), is mainly controlled by the tip apex. Thus, the ability to image, manipulate and chemically identify single atoms in semiconductor surfaces is ultimately determined by the apex structure and its composition. Here we present a detailed and systematic study of the most common structures that can be expected at the apex of the Si tips used in experiments. We tackle the determination of the structure and stability of Si tips with three different approaches: (i) first principles simulations of small tip apexes; (ii) simulated annealing of a Si cluster; and (iii) a minima hopping study of large Si tips. We have probed the tip apexes by making atomic contacts between the tips and then compared force-distance curves with the experimental short range forces obtained with dynamic force spectroscopy. The main conclusion is that although there are multiple stable solutions for the atomically sharp tip apexes, they can be grouped into a few types with characteristic atomic structures and properties. We also show that the structure of the last atomic layers in a tip apex can be both crystalline and amorphous. We corroborate that the atomically sharp tips are thermodynamically stable and that the tip-surface interaction helps to produce the atomic protrusion needed to get atomic resolution.

A numerical study on the behavior of the water meniscus formed between a flat surface and a flat or circular tip

Energy Technology Data Exchange (ETDEWEB)

Son, Sung Wan; Ha, Man Yeong; Yoon, Hyun Sik; Kim, Chang Min [Pusan National University, Busan (Korea, Republic of); Kim, Sang Sun [Korea Aerospace Industries, Sacheon (Korea, Republic of)

2014-04-15

We numerically investigated the behavior of the water meniscus formed between a flat surface and a tip surface, which is flat or circular in shape, using the lattice Boltzmann method (LBM). The shape of the water meniscus formed between the flat bottom surface and the tip surface depends on the tip shape and the interaction between the water meniscus and the bottom or tip surface. The interaction is determined by the contact angles of the bottom and tip surfaces, resulting in different contact lengths between the water meniscus and the bottom or tip surface. The difference in these contact lengths depends on the effects of both the tip curvature and the interaction between the water meniscus and the bottom or tip surface. We classified the shapes of the water meniscus into seven different patterns as a function of the contact angles of the flat bottom and tip surfaces: concave, semi-concave, inverse semi-concave, column, convex, semiconvex, and inverse semi-convex.

A numerical study on the behavior of the water meniscus formed between a flat surface and a flat or circular tip

International Nuclear Information System (INIS)

Son, Sung Wan; Ha, Man Yeong; Yoon, Hyun Sik; Kim, Chang Min; Kim, Sang Sun

2014-01-01

We numerically investigated the behavior of the water meniscus formed between a flat surface and a tip surface, which is flat or circular in shape, using the lattice Boltzmann method (LBM). The shape of the water meniscus formed between the flat bottom surface and the tip surface depends on the tip shape and the interaction between the water meniscus and the bottom or tip surface. The interaction is determined by the contact angles of the bottom and tip surfaces, resulting in different contact lengths between the water meniscus and the bottom or tip surface. The difference in these contact lengths depends on the effects of both the tip curvature and the interaction between the water meniscus and the bottom or tip surface. We classified the shapes of the water meniscus into seven different patterns as a function of the contact angles of the flat bottom and tip surfaces: concave, semi-concave, inverse semi-concave, column, convex, semiconvex, and inverse semi-convex

Contact assembly of cell-laden hollow microtubes through automated micromanipulator tip locating

International Nuclear Information System (INIS)

Wang, Huaping; Shi, Qing; Guo, Yanan; Li, Yanan; Sun, Tao; Huang, Qiang; Fukuda, Toshio

2017-01-01

This paper presents an automated contact assembly method to fabricate a cell-laden microtube based on accurate locating of the micromanipulator tip. Essential for delivering nutrients in thick engineered tissues, a vessel-mimetic microtube can be precisely assembled through microrobotic contact biomanipulation. The biomanipulation is a technique to spatially order and immobilize cellular targets with high precision. However, due to image occlusion during contact, it is challenging to locate the micromanipulator tip for fully automated assembly. To achieve pixel-wise tracking and locating of the tip in contact, a particle filter algorithm integrated with a determined level set model is employed here. The model ensures precise convergence of the micromanipulator’s contour during occlusion. With the converged active contour, the algorithm is able to pixel-wisely separate the micromanipulator from the low-contrast background and precisely locate the tip with error around 1 pixel (2 µ m at 4  ×  magnification). As a result, the cell-laden microtube is automatically assembled at six layers/min, which is effective enough to fabricate vessel-mimetic constructs for vascularization in tissue engineering. (paper)

Kaplan turbine tip vortex cavitation - analysis and prevention

Science.gov (United States)

Motycak, L.; Skotak, A.; Kupcik, R.

2012-11-01

The work is focused on one type of Kaplan turbine runner cavitation - a tip vortex cavitation. For detailed description of the tip vortex, the CFD analysis is used. On the basis of this analysis it is possible to estimate the intensity of cavitating vortex core, danger of possible blade surface and runner chamber cavitation pitting. In the paper, the ways how to avoid the pitting effect of the tip vortex are described. In order to prevent the blade surface against pitting, the following possibilities as the change of geometry of the runner blade, dimension of tip clearance and finally the installation of the anti-cavitation lips are discussed. The knowledge of the shape and intensity of the tip vortex helps to design the anti-cavitation lips more sophistically. After all, the results of the model tests of the Kaplan runner with or without anti-cavitation lips and the results of the CFD analysis are compared.

Characteristics of ovulation method acceptors: a cross-cultural assessment.

Science.gov (United States)

Klaus, H; Labbok, M; Barker, D

1988-01-01

Five programs of instruction in the ovulation method (OM) in diverse geographic and cultural settings are described, and characteristics of approximately 200 consecutive OM acceptors in each program are examined. Major findings include: the religious background and family size of acceptors are variable, as is the level of previous contraceptive use. Acceptors are drawn from a wide range of socioeconomic and religious backgrounds; however, family planning intention was similarly distributed in all five countries. In sum, the ovulation method is accepted by persons from a variety of backgrounds within and between cultural setting.

Pre-Liver Transplant: Tips Versus Distal Splenorenal Shunt

Directory of Open Access Journals (Sweden)

Thomas W. Faust

1997-01-01

Full Text Available Recurrent variceal bleeding in liver transplant candidates with end-stage liver disease can complicate or even prohibit a subsequent transplant procedure (OLT. Endoscopic sclero-therapy and medical therapy are considered as first-line management with surgical shunts reserved for refractory situations. Surgical shunts can be associated with a high mortality in this population and may complicate subsequent OLT. The transjugular intrahepatic portosystemic shunt (TIPS has been recommended in these patients as a bridge to OLT. This is a new modality that has not been compared with previously established therapies such as the distal splenorenal shunt (DSRS. In this study we report our experience with 35 liver transplant recipients who had a previous TIPS (18 patients or DSRS (17 patients for variceal bleeding. The TIPS group had a significantly larger proportion of critically ill and Child-Pugh C patients. Mean operating time was more prolonged in the DSRS group (P=0.014 but transfusion requirements were similar. Intraoperative portal vein blood flow measurements averaged 2132±725 ml/min in the TIPS group compared with 1120±351ml/min in the DSRS group (P<0.001. Arterial flows were similar. Mean ICU and hospital stays were similar. There were 3 hospital mortalities in the DSRS group and none in the TIPS group (P=0.1. We conclude that TIPS is a valuable tool in the management of recurrent variceal bleeding prior to liver transplantation. Intra0Perative hemodynamic measurements suggest a theoretical advantage with TIPS. In a group of patients with advanced liver disease we report an outcome that is similar to patients treated with DSRS prior to liver transplantation. The role of TIPS in the treatment of nontransplant candidates remains to be clarified.

Origin choice and petal loss in the flower garden of spiral wave tip trajectories.

Science.gov (United States)

Gray, Richard A; Wikswo, John P; Otani, Niels F

2009-09-01

Rotating spiral waves have been observed in numerous biological and physical systems. These spiral waves can be stationary, meander, or even degenerate into multiple unstable rotating waves. The spatiotemporal behavior of spiral waves has been extensively quantified by tracking spiral wave tip trajectories. However, the precise methodology of identifying the spiral wave tip and its influence on the specific patterns of behavior remains a largely unexplored topic of research. Here we use a two-state variable FitzHugh-Nagumo model to simulate stationary and meandering spiral waves and examine the spatiotemporal representation of the system's state variables in both the real (i.e., physical) and state spaces. We show that mapping between these two spaces provides a method to demarcate the spiral wave tip as the center of rotation of the solution to the underlying nonlinear partial differential equations. This approach leads to the simplest tip trajectories by eliminating portions resulting from the rotational component of the spiral wave.

Research on fuzzy comprehensive assessment method of nuclear power plant safety culture

International Nuclear Information System (INIS)

Xiang Yuanyuan; Chen Xukun; Xu Rongbin

2012-01-01

Considering the traits of safety culture in nuclear plant, 38 safety culture assessment indexes are established from 4 aspects such as safety values, safety institution, safety behavior and safety sub- stances. Based on it, a comprehensive assessment method for nuclear power plant safety culture is constructed by using AHP (Analytic Hierarchy Process) approach and fuzzy mathematics. The comprehensive assessment method has the quality of high precision and high operability, which can support the decision making of safety culture development. (authors)

In situ scanning tunneling microscope tip treatment device for spin polarization imaging

Science.gov (United States)

Li, An-Ping [Oak Ridge, TN; Jianxing, Ma [Oak Ridge, TN; Shen, Jian [Knoxville, TN

2008-04-22

A tip treatment device for use in an ultrahigh vacuum in situ scanning tunneling microscope (STM). The device provides spin polarization functionality to new or existing variable temperature STM systems. The tip treatment device readily converts a conventional STM to a spin-polarized tip, and thereby converts a standard STM system into a spin-polarized STM system. The tip treatment device also has functions of tip cleaning and tip flashing a STM tip to high temperature (>2000.degree. C.) in an extremely localized fashion. Tip coating functions can also be carried out, providing the tip sharp end with monolayers of coating materials including magnetic films. The device is also fully compatible with ultrahigh vacuum sample transfer setups.

Flouroscopically–guided transhepatic puncture for difficult TIPS re-do procedures utilizing the En Snare retrieval device: A new approach to occluded TIPS in patients with recurrent ascites

International Nuclear Information System (INIS)

Stambo, Glenn W.; Berlet, Matthew H.

2012-01-01

Portal hypertension and variceal bleeding are complications due to cirrhosis. Transjugular Intraphepatic Portosystemic shunt (TIPS) procedure is a well-established treatment for recurrent ascites and variceal bleeding related to portal hypertension. After a TIPS has been placed, the potential of TIPS occlusion or stenosis is high. A TIPS re-do procedure has been used in treatment of progressive clinical symptoms. The standard approach is via the jugular route to recannulate the TIPS shunt. Rarely, it cannot be performed from the jugular approach. Therefore, a fluoroscopically -guided transhepatic approach has been devised for these difficult situations. This case describes the use of the transhepatic route through an indwelling Viatorr covered stent utilizing an En-Snare device to help complete the TIPS re-do procedure. With this newer approach to TIPS re-do procedures, endovascular specialists can achieve TIPS patency despite difficult venous anatomical challenges and the various types of available TIPS stents presently on the market.

Use of Tissue Culture Techniques for Producing Virus-Free Plant in Garlic and Their Identification through Real-Time PCR

Directory of Open Access Journals (Sweden)

Hatıra Taşkın

2013-01-01

Full Text Available This study was performed for comparison of meristem culture technique with shoot tip culture technique for obtaining virus-free plant, comparison of micropropagation success of two different nutrient media, and determination of effectiveness of real-time PCR assay for the detection of viruses. Two different garlic species (Allium sativum and Allium tuncelianum and two different nutrient media were used in this experiment. Results showed that Medium 2 was more successful compared to Medium 1 for both A. tuncelianum and A. sativum (Kastamonu garlic clone. In vitro plants obtained via meristem and shoot tip cultures were tested for determination of onion yellow dwarf virus (OYDV and leek yellow stripe virus (LYSV through real-time PCR assay. In garlic plants propagated via meristem culture, we could not detect any virus. OYDV and LYSV viruses were detected in plants obtained via shoot tip culture. OYDV virus was observed in amount of 80% and 73% of tested plants for A. tuncelianum and A. sativum, respectively. LYSV virus was found in amount of 67% of tested plants of A. tuncelianum and in amount of 87% of tested plants of A. sativum in this study.

Crack Tip Mechanics in Distortion Gradient Plasticity

DEFF Research Database (Denmark)

Fuentes-Alonso, Sandra; Martínez Pañeda, Emilio

2017-01-01

Gradient Plasticity (DGP), the influence on crack tip mechanics of DGP's distinguishing features that entail superior modelling capabilities has not been investigated yet. In this work crack tip fields are thoroughly examined by implementing the higher order theory of DGP in an implicit finite element...

Centrifugal compressor tip clearance and impeller flow

Energy Technology Data Exchange (ETDEWEB)

Jaatinen-Varri, Ahti; Tiainen, Jonna; Turunen-Saaresti, Teemu; Gronman, Aki; Ameli, Alireza; Backman, Jari [Laboratory of Fluid Dynamics, LUT School of Energy Systems, Lappeenranta University of Technology, Lappeenranta (Finland); Engeda, Abraham [Turbomachinery Laboratory, Dept. of Mechanical Engineering, Michigan State University, East Lansing (United States)

2016-11-15

Compressors consume a considerable portion of the electricity used in the industrial sector. Hence, improvements in compressor efficiency lead to energy savings and reduce environmental impacts. The efficiency of an unshrouded centrifugal compressor suffers from leakage flow over the blade tips. The effect of tip leakage flow on the passage flow differs between the full and splitter blade passages. In this study, the differences in the flow fields between the full and splitter blade passages were studied numerically in detail. An industrial high-speed compressor with a design pressure ratio of 1.78 was modelled. Numerical studies were conducted with six different tip clearances and three different diffuser widths. The results show that increasing tip clearance considerably increases the reversed flow into the impeller with an unpinched diffuser. The reversed flow then partly mixes into the flow in the same blade passage it entered the impeller and the rest migrates over the blade, mixing with the tip clearance flow. Furthermore, as the reversed and clearance flow mix into the wake, the wake is weakened. As pinch reduces both the reversed flow and clearance flow, the passage wakes are stronger with pinches. However, the pinch is beneficial as the losses at the impeller outlet decrease.

Centrifugal compressor tip clearance and impeller flow

International Nuclear Information System (INIS)

Jaatinen-Varri, Ahti; Tiainen, Jonna; Turunen-Saaresti, Teemu; Gronman, Aki; Ameli, Alireza; Backman, Jari; Engeda, Abraham

2016-01-01

Compressors consume a considerable portion of the electricity used in the industrial sector. Hence, improvements in compressor efficiency lead to energy savings and reduce environmental impacts. The efficiency of an unshrouded centrifugal compressor suffers from leakage flow over the blade tips. The effect of tip leakage flow on the passage flow differs between the full and splitter blade passages. In this study, the differences in the flow fields between the full and splitter blade passages were studied numerically in detail. An industrial high-speed compressor with a design pressure ratio of 1.78 was modelled. Numerical studies were conducted with six different tip clearances and three different diffuser widths. The results show that increasing tip clearance considerably increases the reversed flow into the impeller with an unpinched diffuser. The reversed flow then partly mixes into the flow in the same blade passage it entered the impeller and the rest migrates over the blade, mixing with the tip clearance flow. Furthermore, as the reversed and clearance flow mix into the wake, the wake is weakened. As pinch reduces both the reversed flow and clearance flow, the passage wakes are stronger with pinches. However, the pinch is beneficial as the losses at the impeller outlet decrease

Identification and functional analysis of endothelial tip cell-enriched genes.

Science.gov (United States)

del Toro, Raquel; Prahst, Claudia; Mathivet, Thomas; Siegfried, Geraldine; Kaminker, Joshua S; Larrivee, Bruno; Breant, Christiane; Duarte, Antonio; Takakura, Nobuyuki; Fukamizu, Akiyoshi; Penninger, Josef; Eichmann, Anne

2010-11-11

Sprouting of developing blood vessels is mediated by specialized motile endothelial cells localized at the tips of growing capillaries. Following behind the tip cells, endothelial stalk cells form the capillary lumen and proliferate. Expression of the Notch ligand Delta-like-4 (Dll4) in tip cells suppresses tip cell fate in neighboring stalk cells via Notch signaling. In DLL4(+/-) mouse mutants, most retinal endothelial cells display morphologic features of tip cells. We hypothesized that these mouse mutants could be used to isolate tip cells and so to determine their genetic repertoire. Using transcriptome analysis of retinal endothelial cells isolated from DLL4(+/-) and wild-type mice, we identified 3 clusters of tip cell-enriched genes, encoding extracellular matrix degrading enzymes, basement membrane components, and secreted molecules. Secreted molecules endothelial-specific molecule 1, angiopoietin 2, and apelin bind to cognate receptors on endothelial stalk cells. Knockout mice and zebrafish morpholino knockdown of apelin showed delayed angiogenesis and reduced proliferation of stalk cells expressing the apelin receptor APJ. Thus, tip cells may regulate angiogenesis via matrix remodeling, production of basement membrane, and release of secreted molecules, some of which regulate stalk cell behavior.

Belgium's burning coal tips. Coupling thermographic ASTER imagery with topography to map debris slide susceptibility

Energy Technology Data Exchange (ETDEWEB)

Nyssen, Jan; Diependaele, Stijn; Goossens, Rudi [Ghent Univ. (Belgium). Dept. of Geography

2012-03-15

Burning coal tips and the debris slides induced by this combustion are a potential danger for local residents and visitors, and a method is required to identify areas of susceptibility. The relatively easy circulation of air, enhanced by the poor compaction of the spoil heaps, and the exothermic reaction of pyrite with oxygen may ignite coal tips. Rainwater infiltration and subsequent evaporation inside burning coal tips may create steam pressure, which, combined with humidity and slope steepness can then trigger landsliding. Based on mapping of debris slides and susceptibility factors such as burning (represented by positive surface temperature anomalies on thermographic imagery) and slope gradient, this study aims to define thresholds for debris slide susceptibility on coal tips and to map potential debris slide source areas on spoil heaps. The Belgian coal tips were used as study area. A DTM as well as ASTER Kinetic Surface Temperature products were used to measure slope gradients and temperature anomaly. Locations with typical characteristics of combustion (heat, red soil colour, steam and gases), and debris slides were recorded in the field, and were used to identify thresholds beyond which debris sliding is generally observed: a temperature anomaly of > 0.5 K, when comparing the debris slide areas to the average temperature of the coal tip, and a slope gradient {>=} 28 . The susceptibility zones for debris slide detachment were mapped by considering the imagery pixels that exceeded the thresholds for temperature and slope gradient; the results fitted well when compared with the observed debris slides. The method can be improved by using more coal tips for calibration, and by taking into account rain depth and slope aspect. (orig.)

Improved Cell Culture Method for Growing Contracting Skeletal Muscle Models

Science.gov (United States)

Marquette, Michele L.; Sognier, Marguerite A.

2013-01-01

An improved method for culturing immature muscle cells (myoblasts) into a mature skeletal muscle overcomes some of the notable limitations of prior culture methods. The development of the method is a major advance in tissue engineering in that, for the first time, a cell-based model spontaneously fuses and differentiates into masses of highly aligned, contracting myotubes. This method enables (1) the construction of improved two-dimensional (monolayer) skeletal muscle test beds; (2) development of contracting three-dimensional tissue models; and (3) improved transplantable tissues for biomedical and regenerative medicine applications. With adaptation, this method also offers potential application for production of other tissue types (i.e., bone and cardiac) from corresponding precursor cells.

A novel nano-hydroxyapatite — PMMA hybrid scaffolds adopted by conjugated thermal induced phase separation (TIPS) and wet-chemical approach: Analysis of its mechanical and biological properties

Energy Technology Data Exchange (ETDEWEB)

G, Radha [National Centre for Nanoscience and Nanotechnology, University of Madras, Guindy Campus, Chennai 600025 (India); S, Balakumar, E-mail: balasuga@yahoo.com [National Centre for Nanoscience and Nanotechnology, University of Madras, Guindy Campus, Chennai 600025 (India); Venkatesan, Balaji; Vellaichamy, Elangovan [Department of Biochemistry, University of Madras, Guindy Campus, Chennai 600025 (India)

2017-06-01

In this study, we report the preparation of nano-hydroxyapatite (nHAp) incorporated poly(methyl methacrylate) (PMMA) scaffolds by conjugated thermal induced phase separation (TIPS) and wet-chemical approach, which essentially facilitates the enhancement of both mechanical as well as biological properties of the scaffolds. The dissolution of PMMA was accomplished by acetone (Ace scaffold), ethanol-water (E-W scaffold) and isopropanol-water (I-W scaffold) mixtures as solvents. The existence of nHAp in PMMA matrix was investigated systematically. The higher degree of porous architecture was achieved from Ace scaffolds compared to both I-W and E-W scaffolds. On the other hand, the dense porous architecture of the I-W scaffold exhibited superior hardness and compressive strength than that of the Ace and E-W scaffolds. All the fabricated samples demonstrated enhanced in vitro bioactivity with respect to increasing immersion period as a result of flower-like in vitro apatite layer formation. The MTT assay was carried out for 1 day and 3 day culture using Saos-2 osteoblast-like cells, which showed better cell proliferation with increasing culture period owing to the interconnected pore architecture of scaffolds and the rational hemocompatibility as per the ASTM standard F756-00. - Highlights: • Conjugated TIPS – wet chemical derived strategy was adopted for PMMA-nHAp composite scaffolds preparation. • TIPS method was carried out by varying solvents such as acetone, isopropanol-water and ethanol-water mixtures. • The impact of solvents on porosity and mechanical properties has been explored. • The existence of nHAp in PMMA has improved in-vitro bioactivity through apatitic-flowers formation. • Hemocompatibility of the scaffolds are in agreement with ASTM standards.

Computational local stiffness analysis of biological cell: High aspect ratio single wall carbon nanotube tip

Energy Technology Data Exchange (ETDEWEB)

TermehYousefi, Amin, E-mail: at.tyousefi@gmail.com [Department of Human Intelligence Systems, Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology (Kyutech) (Japan); Bagheri, Samira; Shahnazar, Sheida [Nanotechnology & Catalysis Research Centre (NANOCAT), IPS Building, University Malaya, 50603 Kuala Lumpur (Malaysia); Rahman, Md. Habibur [Department of Computer Science and Engineering, University of Asia Pacific, Green Road, Dhaka-1215 (Bangladesh); Kadri, Nahrizul Adib [Department of Biomedical Engineering, Faculty of Engineering, University Malaya, 50603 Kuala Lumpur (Malaysia)

2016-02-01

Carbon nanotubes (CNTs) are potentially ideal tips for atomic force microscopy (AFM) due to the robust mechanical properties, nanoscale diameter and also their ability to be functionalized by chemical and biological components at the tip ends. This contribution develops the idea of using CNTs as an AFM tip in computational analysis of the biological cells. The proposed software was ABAQUS 6.13 CAE/CEL provided by Dassault Systems, which is a powerful finite element (FE) tool to perform the numerical analysis and visualize the interactions between proposed tip and membrane of the cell. Finite element analysis employed for each section and displacement of the nodes located in the contact area was monitored by using an output database (ODB). Mooney–Rivlin hyperelastic model of the cell allows the simulation to obtain a new method for estimating the stiffness and spring constant of the cell. Stress and strain curve indicates the yield stress point which defines as a vertical stress and plan stress. Spring constant of the cell and the local stiffness was measured as well as the applied force of CNT-AFM tip on the contact area of the cell. This reliable integration of CNT-AFM tip process provides a new class of high performance nanoprobes for single biological cell analysis. - Graphical abstract: This contribution develops the idea of using CNTs as an AFM tip in computational analysis of the biological cells. The proposed software was ABAQUS 6.13 CAE/CEL provided by Dassault Systems. Finite element analysis employed for each section and displacement of the nodes located in the contact area was monitored by using an output database (ODB). Mooney–Rivlin hyperelastic model of the cell allows the simulation to obtain a new method for estimating the stiffness and spring constant of the cell. Stress and strain curve indicates the yield stress point which defines as a vertical stress and plan stress. Spring constant of the cell and the local stiffness was measured as well

Modular design of AFM probe with sputtered silicon tip

DEFF Research Database (Denmark)

Rasmussen, Peter; Thaysen, Jacob; Bouwstra, Siebe

2001-01-01

of the thin films constituting the cantilever. The AFM probe has an integrated tip made of a thick sputtered silicon layer, which is deposited after the probe has been defined and just before the cantilevers are released. The tips are so-called rocket tips made by reactive ion etching. We present probes...

21 CFR 880.6025 - Absorbent tipped applicator.

Science.gov (United States)

2010-04-01

... stick. The device is used to apply medications to, or to take specimens from, a patient. (b...) MEDICAL DEVICES GENERAL HOSPITAL AND PERSONAL USE DEVICES General Hospital and Personal Use Miscellaneous Devices § 880.6025 Absorbent tipped applicator. (a) Identification. An absorbent tipped applicator is a...

Comparing rapid and culture indicator bacteria methods at inland lake beaches

Science.gov (United States)

Francy, Donna S.; Bushon, Rebecca N.; Brady, Amie M.G.; Kephart, Christopher M.

2013-01-01

A rapid method, quantitative polymerase chain reaction (qPCR), for quantifying indicator bacteria in recreational waters is desirable for public health protection. We report that replacing current Escherichia coli standards with new US Environmental Protection Agency beach action values (BAVs) for enterococci by culture or qPCR may result in more advisories being posted at inland recreational lakes. In this study, concentrations of E. coli and enterococci by culture methods were compared to concentrations of Enterococcus spp. by qPCR at 3 inland lake beaches in Ohio. The E. coli and enterococci culture results were significantly related at all beaches; however, the relations between culture results and Enterococcus spp. qPCR results were not always significant and differed among beaches. All the qPCR results exceeded the new BAV for Enterococcus spp. by qPCR, whereas only 23.7% of culture results for E. coli and 79% of culture results for enterococci exceeded the current standard for E. coli or BAV for enterococci.

Some observations of tip-vortex cavitation

Science.gov (United States)

Arndt, R. E. A.; Arakeri, V. H.; Higuchi, H.

1991-08-01

Cavitation has been observed in the trailing vortex system of an elliptic platform hydrofoil. A complex dependence on Reynolds number and gas content is noted at inception. Some of the observations can be related to tension effects associated with the lack of sufficiently large-sized nuclei. Inception measurements are compared with estimates of pressure in the vortex obtained from LDV measurements of velocity within the vortex. It is concluded that a complete correlation is not possible without knowledge of the fluctuating levels of pressure in tip-vortex flows. When cavitation is fully developed, the observed tip-vortex trajectory flows. When cavitation is fully developed, the observed tip-vortex trajectory shows a surprising lack of dependence on any of the physical parameters varied, such as angle of attack, Reynolds number, cavitation number, and dissolved gas content.

Triangulation and the importance of establishing valid methods for food safety culture evaluation.

Science.gov (United States)

Jespersen, Lone; Wallace, Carol A

2017-10-01

The research evaluates maturity of food safety culture in five multi-national food companies using method triangulation, specifically self-assessment scale, performance documents, and semi-structured interviews. Weaknesses associated with each individual method are known but there are few studies in food safety where a method triangulation approach is used for both data collection and data analysis. Significantly, this research shows that individual results taken in isolation can lead to wrong conclusions, resulting in potentially failing tactics and wasted investments. However, by applying method triangulation and reviewing results from a range of culture measurement tools it is possible to better direct investments and interventions. The findings add to the food safety culture paradigm beyond a single evaluation of food safety culture using generic culture surveys. Copyright © 2017. Published by Elsevier Ltd.

Effect of tip geometry on photo-electron-emission from nanostructures.

Science.gov (United States)

Teki, Ranganath; Lu, Toh-Ming; Koratkar, Nikhil

2009-03-01

We show in this paper the strong effect of tip geometry on the photo-electron-emission behavior of nanostructured surfaces. To study the effect of tip geometry we compared the photo-emissivity of Ru and Pt nanorods with pyramidal shaped tips to that of carbon nanorods that display flat top (planar) tips. Flat top architectures gave no significant increase in the emission current, while nanostructures with pyramidal shaped tips showed 3-4 fold increase in photo-emission compared to a thin film of the same material. Pyramidal tip geometries increase the effective surface area that is exposed to the incident photon-flux thereby enhancing the photon-collection probability of the system. Such nano-structured surfaces show promise in a variety of device applications such as photo-detectors, photon counters and photo-multiplier tubes.

An evaluation of fossil tip-dating versus node-age calibrations in tetraodontiform fishes (Teleostei: Percomorphaceae).

Science.gov (United States)

Arcila, Dahiana; Alexander Pyron, R; Tyler, James C; Ortí, Guillermo; Betancur-R, Ricardo

2015-01-01

Time-calibrated phylogenies based on molecular data provide a framework for comparative studies. Calibration methods to combine fossil information with molecular phylogenies are, however, under active development, often generating disagreement about the best way to incorporate paleontological data into these analyses. This study provides an empirical comparison of the most widely used approach based on node-dating priors for relaxed clocks implemented in the programs BEAST and MrBayes, with two recently proposed improvements: one using a new fossilized birth-death process model for node dating (implemented in the program DPPDiv), and the other using a total-evidence or tip-dating method (implemented in MrBayes and BEAST). These methods are applied herein to tetraodontiform fishes, a diverse group of living and extinct taxa that features one of the most extensive fossil records among teleosts. Previous estimates of time-calibrated phylogenies of tetraodontiforms using node-dating methods reported disparate estimates for their age of origin, ranging from the late Jurassic to the early Paleocene (ca. 150-59Ma). We analyzed a comprehensive dataset with 16 loci and 210 morphological characters, including 131 taxa (95 extant and 36 fossil species) representing all families of fossil and extant tetraodontiforms, under different molecular clock calibration approaches. Results from node-dating methods produced consistently younger ages than the tip-dating approaches. The older ages inferred by tip dating imply an unlikely early-late Jurassic (ca. 185-119Ma) origin for this order and the existence of extended ghost lineages in their fossil record. Node-based methods, by contrast, produce time estimates that are more consistent with the stratigraphic record, suggesting a late Cretaceous (ca. 86-96Ma) origin. We show that the precision of clade age estimates using tip dating increases with the number of fossils analyzed and with the proximity of fossil taxa to the node under

100 Consejos para los Padres (100 Tips for Parents).

Science.gov (United States)

Department of Education, Washington, DC.

Noting that involved parents can improve their children's chances of succeeding in school, this packet of Spanish-language cards offers 100 tips created to help parents become more involved in their child's education. Following a card of general tips on becoming involved, tips are offered in the following topic areas: keeping a child alcohol,…

Influence of CVD diamond tips and Er:YAG laser irradiation on bonding of different adhesive systems to dentin

OpenAIRE

da Silva, Melissa Aline [UNESP; Nicolo, Rebeca Di [UNESP; Barcellos, Daphne Camara [UNESP; Batista, Graziela Ribeiro [UNESP; Pucci, Cesar Rogerio [UNESP; Torres, Carlos Rocha Gomes [UNESP; Borges, Alessandra Bühler [UNESP

2013-01-01

Aim: The aim of this study was to compare the microtensile bond strength of three adhesive systems, using different methods of dentin preparation. Materials and methods: A hundred and eight bovine teeth were used. The dentin from buccal face was exposed and prepared with three different methods, divided in 3 groups: Group 1 (DT)- diamond tip on a high-speed handpiece; Group 2 (CVD)-CVD tip on a ultrasonic handpiece; Group 3 (LA)-Er: YAG laser. The teeth were divided into 3 subgroups, accordin...

A Non-Uniformly Under-Sampled Blade Tip-Timing Signal Reconstruction Method for Blade Vibration Monitoring

Directory of Open Access Journals (Sweden)

Zheng Hu

2015-01-01

Full Text Available High-speed blades are often prone to fatigue due to severe blade vibrations. In particular, synchronous vibrations can cause irreversible damages to the blade. Blade tip-timing methods (BTT have become a promising way to monitor blade vibrations. However, synchronous vibrations are unsuitably monitored by uniform BTT sampling. Therefore, non-equally mounted probes have been used, which will result in the non-uniformity of the sampling signal. Since under-sampling is an intrinsic drawback of BTT methods, how to analyze non-uniformly under-sampled BTT signals is a big challenge. In this paper, a novel reconstruction method for non-uniformly under-sampled BTT data is presented. The method is based on the periodically non-uniform sampling theorem. Firstly, a mathematical model of a non-uniform BTT sampling process is built. It can be treated as the sum of certain uniform sample streams. For each stream, an interpolating function is required to prevent aliasing in the reconstructed signal. Secondly, simultaneous equations of all interpolating functions in each sub-band are built and corresponding solutions are ultimately derived to remove unwanted replicas of the original signal caused by the sampling, which may overlay the original signal. In the end, numerical simulations and experiments are carried out to validate the feasibility of the proposed method. The results demonstrate the accuracy of the reconstructed signal depends on the sampling frequency, the blade vibration frequency, the blade vibration bandwidth, the probe static offset and the number of samples. In practice, both types of blade vibration signals can be particularly reconstructed by non-uniform BTT data acquired from only two probes.

Thulium fiber laser lithotripsy using a muzzle brake fiber tip

Science.gov (United States)

Hutchens, Thomas C.; Gonzalez, David A.; Irby, Pierce B.; Fried, Nathaniel M.

2017-02-01

The Thulium fiber laser (TFL) is being explored as an alternative to Holmium:YAG laser for lithotripsy. TFL beam profile allows coupling of higher power into smaller fibers than multimode Holmium laser beam, without proximal fiber tip degradation. A smaller fiber provides more space in ureteroscope working channel for increased saline irrigation and allows maximum ureteroscope flexion. However, distal fiber tip burnback increases as fiber diameter decreases. Previous studies utilizing hollow steel sheaths around recessed distal fiber tips reduced fiber burnback, but increased retropulsion. In this study, a "fiber muzzle brake" was tested for reducing fiber burnback and stone retropulsion. TFL lithotripsy studies were performed at 1908 nm, 35 mJ, 500 μs, and 300 Hz using a 100-μm-core fiber. The optimal stainless steel muzzle brake tip tested consisted of a 1-cm-long, 560-μm-OD, 360-μm-ID tube with 275-μm thru hole located 250-μm from the distal end. The fiber tip was recessed a distance of 500 μm. Stone phantom retropulsion, fiber tip burnback, and calcium oxalate stone ablation studies were performed, ex vivo. Small stones with a mass of 40 +/- 4 mg and 4-mm-diameter were ablated over a 1.5-mm sieve in 25 +/- 4 s (n=10), without distal fiber tip burnback. Reduction in stone phantom retropulsion distance by 50% and 85% was observed when using muzzle brake tips versus 100-μm-core bare fibers and hollow steel tip fibers. The muzzle brake fiber tip provided efficient stone ablation, reduced stone retropulsion, and minimal fiber degradation during TFL lithotripsy.

Jagged gives endothelial tip cells an edge.

Science.gov (United States)

Suchting, Steven; Eichmann, Anne

2009-06-12

Sprouting blood vessels have tip cells that lead and stalk cells that follow. Benedito et al. (2009) now show that competition between endothelial cells for the tip position is regulated by glycosylation of Notch receptors and by the opposing actions of the Notch ligands Jagged1 and Delta-like 4.

Electron field emission characteristics of carbon nanotube on tungsten tip

International Nuclear Information System (INIS)

Phan Ngoc Hong; Bui Hung Thang; Nguyen Tuan Hong; Phan Ngoc Minh; Lee, Soonil

2009-01-01

Electron field emission characteristic of carbon nanotubes on tungsten tip was investigated in 2x10 -6 Torr vacuum. The measurement results showed that the CNTs/W tip could emit electron at 0.7 V/μm (nearly 10 times lower than that of the W tip itself) and reach up to 26 μA at the electric field of 1 V/μm. The emission characteristic follows the Fowler-Nordheim mechanism. Analysis of the emission characteristic showed that the CNTs/W tip has a very high value of field enhancement factor (β = 4.1 x 10 4 cm -1 ) that is much higher than that of the tungsten tip itself. The results confirmed the excellent field emission behavior of the CNTs materials and the CNTs/W tip is a prospective candidate for advanced electron field emitter.

Performance of Partial and Cavity Type Squealer Tip of a HP Turbine Blade in a Linear Cascade

Directory of Open Access Journals (Sweden)

Levent Kavurmacioglu

2018-01-01

Full Text Available Three-dimensional highly complex flow structure in tip gap between blade tip and casing leads to inefficient turbine performance due to aerothermal loss. Interaction between leakage vortex and secondary flow structures is the substantial source of that loss. Different types of squealer tip geometries were tried in the past, in order to improve turbine efficiency. The current research deals with comparison of partial and cavity type squealer tip concepts for higher aerothermal performance. Effects of squealer tip have been examined comprehensively for an unshrouded HP turbine blade tip geometry in a linear cascade. In the present paper, flow structure through the tip gap was comprehensively investigated by computational fluid dynamic (CFD methods. Numerical calculations were obtained by solving three-dimensional, incompressible, steady, and turbulent form of the Reynolds-averaged Navier-Stokes (RANS equations using a general purpose and three-dimensional viscous flow solver. The two-equation turbulence model, shear stress transport (SST, has been used. The tip profile belonging to the Pennsylvania State University Axial Flow Turbine Research Facility (AFTRF was used to create an extruded solid model of the axial turbine blade. For identifying optimal dimensions of squealer rim in terms of squealer height and squealer width, our previous studies about aerothermal investigation of cavity type squealer tip were utilized. In order to obtain the mesh, an effective parametric generation has been utilized using a multizone structured mesh. Numerical calculations indicate that partial and cavity squealer designs can be effective to reduce the aerodynamic loss and heat transfer to the blade tip. Future efforts will include novel squealer shapes for higher aerothermal performance.

Tip cells: master regulators of tubulogenesis?

Science.gov (United States)

Weavers, Helen; Skaer, Helen

2014-07-01

The normal development of an organ depends on the coordinated regulation of multiple cell activities. Focusing on tubulogenesis, we review the role of specialised cells or groups of cells that are selected from within tissue primordia and differentiate at the outgrowing tips or leading edge of developing tubules. Tip or leading cells develop distinctive patterns of gene expression that enable them to act both as sensors and transmitters of intercellular signalling. This enables them to explore the environment, respond to both tissue intrinsic signals and extrinsic cues from surrounding tissues and to regulate the behaviour of their neighbours, including the setting of cell fate, patterning cell division, inducing polarity and promoting cell movement and cell rearrangements by neighbour exchange. Tip cells are also able to transmit mechanical tension to promote tissue remodelling and, by interacting with the extracellular matrix, they can dictate migratory pathways and organ shape. Where separate tubular structures fuse to form networks, as in the airways of insects or the vascular system of vertebrates, specialised fusion tip cells act to interconnect disparate elements of the developing network. Finally, we consider their importance in the maturation of mature physiological function and in the development of disease. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Can protoplast production from in vitro cultured shoots of Tanacetum vary during the season?

Directory of Open Access Journals (Sweden)

M. KESKITALO

2008-12-01

Full Text Available Two different experiments were carried out to study the production of protoplasts and the variation of protoplast yield from in vitro cultured shoot tips of tansy (Tanacetum vulgare L. and pyrethrum (Tanacetum cinerariifolium (Trevir. Schiltz-Bip. In the first experiment, light had more pronouced effect for tansy than for pyrethrum. When the donor tissues of tansy were cultured under high light intensity the leaves contained anthocyanin and became brown during enzyme maceration. In contrast, donor tissues cultured under low light intensity produced leaves without anthocyanin. Depending on the light intensity of donor tissues, on average 5.8 - 6.8 x 106 and 3.4 - 4.3 x 106 protoplasts were isolated from one gram of mesophyll leaves of tansy and pyrethrum, respectively. In the second experiment, the production of protoplasts from tansy and pyrethrum varied seasonally. The most successful season for the production of protoplasts from in vitro cultured shoot tips was between December and April, when also the highest number of protoplasts could be isolated. It was not possible to state whether Tanacetum species have rhythms, which could cause physiological or chemical changes for the in vitro grown shoot tips. However, some external or internal, possible seasonal-dependent stimuli may have caused variation in the number of protoplasts isolated from tansy and pyrethrum and favoured protoplast production during winter and spring.

Experimental TIPS with spiral Z-stents in swine with and without induced portal hypertension

International Nuclear Information System (INIS)

Kichikawa, Kimihiko; Saxon, Richard R.; Nishimine, Kiyoshi; Nishida, Norifumi; Uchida, Barry T.

1997-01-01

Purpose. To assess the suitability of spiral Z-stents for transjugular intrahepatic portosystemic shunt (TIPS) and the influence of portal hypertension on shunt patency in young swine. Methods. TIPS were established using spiral Z-stents in 14 domestic swine. In 7 animals, the portal venous pressure was normal; in the other 7, acute portal hypertension was induced by embolization of portal vein branches. Follow-up portal venography and histologic evaluations were done from 1 hr to 12 weeks after TIPS. Results. Follow-up transhepatic portal venograms showed progressive narrowing of the shunt, most priminent in the midportion of the tract. Ingrowth of liver parenchyma between the stent wires found after 3 weeks led to progressive shunt narrowing and shunt occlusion by 12 weeks. A pseudointima grew rapidly inside the stent, peaked in thickness around 4 weeks, and decreased later. Acutely created portal hypertension rapidly returned to normal and there was no difference in TIPS patency between the two groups of animals. Conclusion. Although the spiral Z-stent can be used as a device for creation of TIPS in patients with cirrhotic livers, it is associated with extensive liver ingrowth in swine that leads to rapid shunt occlusion. Portal hypertension was only transient in this model

Alginate-encapsulation of shoot tips of jojoba [Simmondsia chinensis (Link) Schneider] for germplasm exchange and distribution.

Science.gov (United States)

Kumar, Sunil; Rai, Manoj K; Singh, Narender; Mangal, Manisha

2010-12-01

Shoot tips excised from in vitro proliferated shoots derived from nodal explants of jojoba [Simmondsia chinensis (Link) Schneider] were encapsulated in calcium alginate beads for germplasm exchange and distribution. A gelling matrix of 3 % sodium alginate and 100 mM calcium chloride was found most suitable for formation of ideal calcium alginate beads. Best response for shoot sprouting from encapsulated shoot tips was recorded on 0.8 % agar-solidified full-strength MS medium. Rooting was induced upon transfer of sprouted shoots to 0.8 % agar-solidified MS medium containing 1 mg l(-1) IBA. About 70 % of encapsulated shoot tips were rooted and converted into plantlets. Plants regenerated from encapsulated shoot tips were acclimatized successfully. The present encapsulation approach could also be applied as an alternative method of propagation of desirable elite genotype of jojoba.

Minimizing tip-sample forces in jumping mode atomic force microscopy in liquid

Energy Technology Data Exchange (ETDEWEB)

Ortega-Esteban, A. [Departamento de Fisica de la Materia Condensada, C-3, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Horcas, I. [Nanotec Electronica S.L., Centro Empresarial Euronova 3, Ronda de Poniente 12, 28760 Tres Cantos, Madrid (Spain); Hernando-Perez, M. [Departamento de Fisica de la Materia Condensada, C-3, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Ares, P. [Nanotec Electronica S.L., Centro Empresarial Euronova 3, Ronda de Poniente 12, 28760 Tres Cantos, Madrid (Spain); Perez-Berna, A.J.; San Martin, C.; Carrascosa, J.L. [Centro Nacional de Biotecnologia (CNB-CSIC), Darwin 3, 28049 Madrid (Spain); Pablo, P.J. de [Departamento de Fisica de la Materia Condensada, C-3, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Gomez-Herrero, J., E-mail: julio.gomez@uam.es [Departamento de Fisica de la Materia Condensada, C-3, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain)

2012-03-15

Control and minimization of tip-sample interaction forces are imperative tasks to maximize the performance of atomic force microscopy. In particular, when imaging soft biological matter in liquids, the cantilever dragging force prevents identification of the tip-sample mechanical contact, resulting in deleterious interaction with the specimen. In this work we present an improved jumping mode procedure that allows detecting the tip-sample contact with high accuracy, thus minimizing the scanning forces ({approx}100 pN) during the approach cycles. To illustrate this method we report images of human adenovirus and T7 bacteriophage particles which are prone to uncontrolled modifications when using conventional jumping mode. -- Highlights: Black-Right-Pointing-Pointer Improvement in atomic force microscopy in buffer solution. Black-Right-Pointing-Pointer Peak force detection. Black-Right-Pointing-Pointer Subtracting the cantilever dragging force. Black-Right-Pointing-Pointer Forces in the 100 pN range. Black-Right-Pointing-Pointer Imaging of delicate viruses with atomic force microscopy.

Sub-harmonic broadband humps and tip noise in low-speed ring fans.

Science.gov (United States)

Moreau, Stéphane; Sanjose, Marlène

2016-01-01

A joint experimental and numerical study has been achieved on a low-speed axial ring fan in clean inflow. Experimental evidence shows large periodic broadband humps at lower frequencies than the blade passing frequencies and harmonics even at design conditions. These sub-harmonic humps are also found to be sensitive to the fan process and consequently to its tip geometry. Softer fans yield more intense humps more shifted to lower frequencies with respect to the fan harmonics. Unsteady turbulent flow simulations of this ring fan mounted on a test plenum have been achieved by four different methods that have been validated by comparing with overall performances and detailed hot-wire velocity measurements in the wake. Noise predictions are either obtained directly or are obtained through Ffowcs Williams and Hawkings' analogy, and compared with narrowband and third-octave power spectra. All unsteady simulations correctly capture the low flow rates, the coherent vortex dynamics in the tip clearance and consequently the noise radiation dominated by the tip noise in the low- to mid-frequency range. Yet, only the scale-adaptive simulation and the lattice Boltzmann method simulations which can describe most of the turbulent structures accurately provide the proper spectral shape and levels, and consequently the overall sound power level.

The transjugular intrahepatic portosystemic shunt (TIPS)

International Nuclear Information System (INIS)

Owen, A.R.; Stanley, A.J.; Vijayananthan, A.; Moss, J.G.

2009-01-01

The creation of an intrahepatic portosystemic shunt via a transjugular approach (TIPS) is an interventional radiological procedure used to treat the complications of portal hypertension. TIPS insertion is principally indicated to prevent or arrest variceal bleeding when medical or endoscopic treatments fail, and in the management refractory ascites. This review discusses the development and execution of the technique, with focus on its clinical efficacy. Patient selection, imaging surveillance, revision techniques, and complications are also discussed.

The transjugular intrahepatic portosystemic shunt (TIPS)

Energy Technology Data Exchange (ETDEWEB)

Owen, A.R. [Department of Radiology, Austin Health, Heidelberg, Melbourne (Australia)], E-mail: andrewowen@doctors.org.uk; Stanley, A.J. [Department of Gastroenterology, Glasgow Royal Infirmary, Glasgow (United Kingdom); Vijayananthan, A. [Department of Biomedical Imaging, University of Malaya, Kuala Lumpur (Malaysia); Moss, J.G. [Department of Radiology, Gartnavel General Hospital, Glasgow (United Kingdom)

2009-07-15

The creation of an intrahepatic portosystemic shunt via a transjugular approach (TIPS) is an interventional radiological procedure used to treat the complications of portal hypertension. TIPS insertion is principally indicated to prevent or arrest variceal bleeding when medical or endoscopic treatments fail, and in the management refractory ascites. This review discusses the development and execution of the technique, with focus on its clinical efficacy. Patient selection, imaging surveillance, revision techniques, and complications are also discussed.

ZBrush Professional Tips and Techniques

CERN Document Server

Gaboury, Paul

2012-01-01

Learn to work effectively and creatively with all versions of ZBrush! ZBrush is used by top artists in Hollywood to model and sculpt characters in such films as Avatar, Iron Man, and Pirates of the Caribbean. In addition, this amazing technology is also used in jewelry design, forensic science, aerospace, video games, toy creation, and the medical field. Written by Pixologic's in-house ZBrush expert Paul Gaboury, this full-color, beautifully illustrated guide provides you with the ultimate tips and tricks to maximize your use of all versions of ZBrush. Reveals numerous little-known tips and tr

Design and optimization of wing tips for wind turbines. Final report; Design og optimering af vingetipper for vindmoeller. Slutrapport

Energy Technology Data Exchange (ETDEWEB)

Soerensen, J.N.; Shen, W.Z.; Zhu, W.J.; Borbye, J.; Okulov, V.L.; Mikkelsen, R. (DTU Mekanik, Kgs. Lyngby (Denmark)); Gaunaa, M.; Rethore, P.-E.; Soerensen, N.N. (Danmarks Tekniske Univ. Risoe DTU, Afd. for Vindenergi, Roskilde (Denmark))

2011-03-15

The aim of the project was to suggest and analyse new shapes of wing tips for wind turbines to optimize their performance. Several simple wing tips and their flow topology were analysed, and the impact of different design variables was determined in order to establish which design has the best effect for the performance. For the numerical flow calculations, primarily the Navier-Stokes code EllipSys was used. As a supplement to the viscous Navier-Stokes calculations, in-viscous calculations were made using a lifting-line theory. This is a simple technique to determine the load distribution along the wing tip in those cases where viscous effects can be neglected. A large part of the project has focused on improving accuracy of the lifting-line method. Besides forming the basis for improved tip configurations, the calculations were also used to improve the so-called tip correction. Based on the numerical results from CFD calculations an improved tip correction was developed. (ln)

Back-to-School Health Tips: Exercise and Sleep

Science.gov (United States)

... up the same times each day. Keep room temperature on the cool side. A TV or computer in the bedroom can be a distraction. Read More "Back-to-School" Articles Health Tips: Immunizations / Health Tips: Exercise and ...

Lifting Safety: Tips To Help Prevent Back Injuries

Science.gov (United States)

... Prevent Back Injuries Lifting Safety: Tips to Help Prevent Back Injuries Share Print Back injuries are common problems at work, home, and play. They can be caused by accidents or improper lifting technique. Below are tips to ...

Utility of PCR, Culture, and Antigen Detection Methods for Diagnosis of Legionellosis.

Science.gov (United States)

Chen, Derrick J; Procop, Gary W; Vogel, Sherilynn; Yen-Lieberman, Belinda; Richter, Sandra S

2015-11-01

The goal of this retrospective study was to evaluate the performance of different diagnostic tests for Legionnaires' disease in a clinical setting where Legionella pneumophila PCR had been introduced. Electronic medical records at the Cleveland Clinic were searched for Legionella urinary antigen (UAG), culture, and PCR tests ordered from March 2010 through December 2013. For cases where two or more test methods were performed and at least one was positive, the medical record was reviewed for relevant clinical and epidemiologic factors. Excluding repeat testing on a given patient, 19,912 tests were ordered (12,569 UAG, 3,747 cultures, and 3,596 PCR) with 378 positive results. The positivity rate for each method was 0.4% for culture, 0.8% for PCR, and 2.7% for UAG. For 37 patients, at least two test methods were performed with at least one positive result: 10 (27%) cases were positive by all three methods, 16 (43%) were positive by two methods, and 11 (30%) were positive by one method only. For the 32 patients with medical records available, clinical presentation was consistent with proven or probable Legionella infection in 84% of the cases. For those cases, the sensitivities of culture, PCR, and UAG were 50%, 92%, and 96%, respectively. The specificities were 100% for culture and 99.9% for PCR and UAG. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Fabrication of silver tips for scanning tunneling microscope induced luminescence.

Science.gov (United States)

Zhang, C; Gao, B; Chen, L G; Meng, Q S; Yang, H; Zhang, R; Tao, X; Gao, H Y; Liao, Y; Dong, Z C

2011-08-01

We describe a reliable fabrication procedure of silver tips for scanning tunneling microscope (STM) induced luminescence experiments. The tip was first etched electrochemically to yield a sharp cone shape using selected electrolyte solutions and then sputter cleaned in ultrahigh vacuum to remove surface oxidation. The tip status, in particular the tip induced plasmon mode and its emission intensity, can be further tuned through field emission and voltage pulse. The quality of silver tips thus fabricated not only offers atomically resolved STM imaging, but more importantly, also allows us to perform challenging "color" photon mapping with emission spectra taken at each pixel simultaneously during the STM scan under relatively small tunnel currents and relatively short exposure time.

Graded-index fiber tip optical tweezers: numerical simulation and trapping experiment.

Science.gov (United States)

Gong, Yuan; Ye, Ai-Yan; Wu, Yu; Rao, Yun-Jiang; Yao, Yao; Xiao, Song

2013-07-01

Optical fiber tweezers based on a graded-index multimode fiber (GIMMF) tip is proposed. Light propagation characteristics and gradient force distribution near the GIMMF tip are numerically investigated, which are further compared with that of optical fiber tips based on conventional single mode fibers. The simulated results indicated that by selecting optimal GIMMF length, the gradient force of the GIMMF tip tweezers is about 4 times higher than that of the SMF tip tweezers with a same shape. To prove the feasibility of such a new concept, optical trapping of yeast cells with a diameter of ~5 μm using the chemically-etched GIMMF tip is experimentally demonstrated and the trapping force is also calculated.

Combined frequency modulated atomic force microscopy and scanning tunneling microscopy detection for multi-tip scanning probe microscopy applications

International Nuclear Information System (INIS)

Morawski, Ireneusz; Spiegelberg, Richard; Korte, Stefan; Voigtländer, Bert

2015-01-01

A method which allows scanning tunneling microscopy (STM) tip biasing independent of the sample bias during frequency modulated atomic force microscopy (AFM) operation is presented. The AFM sensor is supplied by an electronic circuit combining both a frequency shift signal and a tunneling current signal by means of an inductive coupling. This solution enables a control of the tip potential independent of the sample potential. Individual tip biasing is specifically important in order to implement multi-tip STM/AFM applications. An extensional quartz sensor (needle sensor) with a conductive tip is applied to record simultaneously topography and conductivity of the sample. The high resonance frequency of the needle sensor (1 MHz) allows scanning of a large area of the surface being investigated in a reasonably short time. A recipe for the amplitude calibration which is based only on the frequency shift signal and does not require the tip being in contact is presented. Additionally, we show spectral measurements of the mechanical vibration noise of the scanning system used in the investigations

Combined frequency modulated atomic force microscopy and scanning tunneling microscopy detection for multi-tip scanning probe microscopy applications

Energy Technology Data Exchange (ETDEWEB)

Morawski, Ireneusz [Peter Grünberg Institut (PGI-3) and JARA-Fundamentals of Future Information Technology, Forschungszentrum Jülich, 52425 Jülich (Germany); Institute of Experimental Physics, University of Wrocław, pl. M. Borna 9, 50-204 Wrocław (Poland); Spiegelberg, Richard; Korte, Stefan; Voigtländer, Bert [Peter Grünberg Institut (PGI-3) and JARA-Fundamentals of Future Information Technology, Forschungszentrum Jülich, 52425 Jülich (Germany)

2015-12-15

A method which allows scanning tunneling microscopy (STM) tip biasing independent of the sample bias during frequency modulated atomic force microscopy (AFM) operation is presented. The AFM sensor is supplied by an electronic circuit combining both a frequency shift signal and a tunneling current signal by means of an inductive coupling. This solution enables a control of the tip potential independent of the sample potential. Individual tip biasing is specifically important in order to implement multi-tip STM/AFM applications. An extensional quartz sensor (needle sensor) with a conductive tip is applied to record simultaneously topography and conductivity of the sample. The high resonance frequency of the needle sensor (1 MHz) allows scanning of a large area of the surface being investigated in a reasonably short time. A recipe for the amplitude calibration which is based only on the frequency shift signal and does not require the tip being in contact is presented. Additionally, we show spectral measurements of the mechanical vibration noise of the scanning system used in the investigations.

Resilient leadership and the organizational culture of resilience: construct validation.

Science.gov (United States)

Everly, George S; Smith, Kenneth J; Lobo, Rachel

2013-01-01

Political, economic, and social unrest and uncertainty seem replete throughout the world. Within the United States, political vitriol and economic volatility have led to severe economic restrictions. Both government and private sector organizations are being asked to do more with less. The specter of dramatic changes in healthcare creates a condition of uncertainty affecting budget allocations and hiring practices. If ever there was a time when a "resilient culture" was needed, it is now. In this paper we shall discuss the application of "tipping point" theory (Gladwell, 2000) operationalized through a special form of leadership: "resilient leadership" (Everly, Strouse, Everly, 2010). Resilient leadership is consistent with Gladwells "Law of the Few" and strives to create an organizational culture of resilience by implementing an initial change within no more than 20% of an organization's workforce. It is expected that such a minority, if chosen correctly, will "tip" the rest of the organization toward enhanced resilience, ideally creating a self-sustaining culture of resilience. This paper reports on the empirical foundations and construct validation of "resilient leadership".

Methods and Techniques of Sampling, Culturing and Identifying of Subsurface Bacteria

International Nuclear Information System (INIS)

Lee, Seung Yeop; Baik, Min Hoon

2010-11-01

This report described sampling, culturing and identifying of KURT underground bacteria, which existed as iron-, manganese-, and sulfate-reducing bacteria. The methods of culturing and media preparation were different by bacteria species affecting bacteria growth-rates. It will be possible for the cultured bacteria to be used for various applied experiments and researches in the future

An intelligent control scheme for precise tip-motion control in atomic force microscopy.

Science.gov (United States)

Wang, Yanyan; Hu, Xiaodong; Xu, Linyan

2016-01-01

The paper proposes a new intelligent control method to precisely control the tip motion of the atomic force microscopy (AFM). The tip moves up and down at a high rate along the z direction during scanning, requiring the utilization of a rapid feedback controller. The standard proportional-integral (PI) feedback controller is commonly used in commercial AFMs to enable topography measurements. The controller's response performance is determined by the set of the proportional (P) parameter and the integral (I) parameter. However, the two parameters cannot be automatically altered simultaneously according to the scanning speed and the surface topography during continuors scanning, leading to an inaccurate measurement. Thus a new intelligent controller combining the fuzzy controller and the PI controller is put forward in the paper. The new controller automatically selects the most appropriate PI parameters to achieve a fast response rate on basis of the tracking errors. In the experimental setup, the new controller is realized with a digital signal process (DSP) system, implemented in a conventional AFM system. Experiments are carried out by comparing the new method with the standard PI controller. The results demonstrate that the new method is more robust and effective for the precise tip motion control, corresponding to the achievement of a highly qualified image by shortening the response time of the controller. © Wiley Periodicals, Inc.

Pathology of pulmonary tuberculosis and non-tuberculous mycobacterial lung disease: Facts, misconceptions, and practical tips for pathologists.

Science.gov (United States)

Jain, Deepali; Ghosh, Subha; Teixeira, Lucileia; Mukhopadhyay, Sanjay

2017-11-01

Most pathologists are familiar with the microscopic features of tuberculosis and the need to examine special stains for acid-fast bacteria (AFB) in cases of granulomatous lung disease. However, misconceptions do exist, including the concept that finding AFB in "caseating granulomas" confirms the diagnosis of tuberculosis. This dogma is attributable to the high prevalence of tuberculosis in many countries, as well as unfamiliarity with the microscopic spectrum of non-tuberculous mycobacterial lung disease. This review aims to provide surgical pathologists with practical tips to identify AFB, illustrate the histologic overlap between pulmonary tuberculosis and non-tuberculous mycobacterial lung disease, and highlight the importance of cultures in this setting. M. tuberculosis and non-tuberculous mycobacteria cannot be reliably differentiated either on the basis of the tissue reaction or by bacterial morphology on acid-fast stains. Although a presumptive clinical diagnosis of tuberculosis can be made without culture-confirmation, the only definitive means to determine the true identity of AFB is by cultures or molecular methods. Making this distinction is most critical when AFB are found in incidentally detected lung nodules in geographic locations where the incidence of tuberculosis is low, because in such settings AFB in necrotizing granulomas of the lung are more likely to be non-tuberculous mycobacteria than M. tuberculosis. Copyright © 2017 Elsevier Inc. All rights reserved.

CFD Study on Effective Wake of Conventional and Tip-modified Propellers

DEFF Research Database (Denmark)

Shin, K. W.; Andersen, Poul

2016-01-01

result and the effective wake fractions from integrating CFD velocity fields, 5-15% higher effective wake fractions of tip-modified propellers from the existing estimation method based on the open-water correlation at thrust or torque identity can be related mainly to the effects of Reynolds number...

Use of the Culture Care Theory and ethnonursing method to discover how nursing faculty teach culture care.

Science.gov (United States)

Mixer, Sandra J

2008-04-01

As the world becomes increasingly multicultural, transcultural nursing education is critical to ensuring a culturally competent workforce. This paper presents a comprehensive review of literature and results of an ethnonursing pilot study using the Culture Care Theory (CCT) to discover how nursing faculty teach culture care. The literature revealed that despite 50 years of transcultural nursing knowledge development through theory, research and practice, there remains a lack of formal, integrated culture education in nursing. The importance of faculty providing generic and professional care to nursing students and using an organising framework to teach culture care was discovered. Additionally, care was essential for faculty health and well-being to enable faculty to teach culture care. This unique use of the theory and method demonstrates its usefulness in discovering and describing the complex nature of teaching culture care. Larger scale studies are predicted to further substantiate the CCT, building the discipline of nursing.

Spatial perturbation of a wing-tip vortex using pulsed span-wise jets

Science.gov (United States)

Heyes, A. L.; Smith, D. A. R.

The separation distance required between transport aircraft to avoid wake vortices remains a limiting factor on airport capacity. The dissipation of the wake can be accelerated by perturbing co-operative instabilities between multiple pairs of vortices. This paper presents the results of a preliminary experimental investigation into the use of pulsed span-wise air jets in the wing tip to perturb a single tip vortex in the very near field. Velocity measurements were made using PIV and hot-wire anemometry. The results demonstrate that the vortex position can be modulated at frequencies up to 50 Hz and, as such, the method shows promise for forcing instability in multiple vortex wakes.

Tipping news in information accumulation system

Science.gov (United States)

Shin, J. K.

2010-05-01

As a continuous opinion dynamics model, the information accumulation system (IAS) includes three basic mechanisms of the news, the inheritance and the diffusion as contributing to the information accumulation process of a system. A system is composed of agents who diffuse information through internal interaction, while each of them has incomplete memory or inheritance rate. The news comes from external sources of information, such as mass media. Previously the model IAS was studied only for the small news problems. In this study, a tipping news problem is considered. A key question of the problem is: what is the minimum strength of advertisement that can tip the minority opinion to a majority one? Dynamics of the IAS is briefly revisited with a special interest on nonlinear behavior of the model. In particular, it is shown that a discrete map of the IAS for a single color problem can be transformed into a logistic map, from which the dynamics of the IAS can be better understood. To show the applicability of the IAS model, the result is applied to explain the concept of the critical population size, which claims that there is a minimum population size for a social knowledge system to be continuously inherited without being lost. And critical size of the tipping news is found analytically in terms of IAS parameters. Some of the key results from the present study are compared in detail with the results from the Brownian particle model, which is believed to be the most similar model to the IAS. The concept of tipping news is used to show that a traditional society can tip at an exceptionally low inter-community exposure. Finally, the result was applied to the language competition problem.

On the possible ultrasonic inspection of micro-bubbles generated by the optical fiber tip

Directory of Open Access Journals (Sweden)

V. V. Kazakov

2016-09-01

Full Text Available We demonstrate the possibility of detection and monitoring of bubbles emerging near the tip of an optical fiber by means of ultrasonic method. The excitation of bubbles at their resonant frequencies is performed using short ultrasonic pulses having a wide frequency range simultaneously with their modulation by means of a long pulse of a monochromatic frequency. This method allows detection of bubbles of various sizes. Used signal processing method, which allows increased bubble detection accuracy, is proposed for research in environments of biological-like medium which show continuous variations in structure and properties when exposed to optical emission. The method has been demonstrated on model objects: in a liquid and in a biological tissue phantom using various methods of bubble generation (hydrolysis and optical emission. We studied bubble formation by the tip of a fiber of the surgical laser LSP-007/10 “IRE Polus” with a wavelength of 0.97μm coated with a highly absorbing graphite layer.

Travel Tips Help IBS Sufferers Enjoy Their Vacations

Science.gov (United States)

... can feel more in control when traveling." IFFGD's travel tips include: Allow enough time in the morning to get to the airport ... Heartache 2004-0929 Norton Honored 2004-0525 IBS Travel Tips ... Real World 2001-1119 Heartburn or Heart Attack Commentary ...

Online monitoring of dynamic tip clearance of turbine blades in high temperature environments

Science.gov (United States)

Han, Yu; Zhong, Chong; Zhu, Xiaoliang; Zhe, Jiang

2018-04-01

Minimized tip clearance reduces the gas leakage over turbine blade tips and improves the thrust and efficiency of turbomachinery. An accurate tip clearance sensor, measuring the dynamic clearances between blade tips and the turbine case, is a critical component for tip clearance control. This paper presents a robust inductive tip clearance sensor capable of monitoring dynamic tip clearances of turbine machines in high-temperature environments and at high rotational speeds. The sensor can also self-sense the temperature at a blade tip in situ such that temperature effect on tip clearance measurement can be estimated and compensated. To evaluate the sensor’s performance, the sensor was tested for measuring the tip clearances of turbine blades under various working temperatures ranging from 700 K to 1300 K and at turbine rotational speeds ranging from 3000 to 10 000 rpm. The blade tip clearance was varied from 50 to 2000 µm. The experiment results proved that the sensor can accurately measure the blade tip clearances with a temporal resolution of 10 µm. The capability of accurately measuring the tip clearances at high temperatures (~1300 K) and high turbine rotation speeds (~30 000 rpm), along with its compact size, makes it promising for online monitoring and active control of blade tip clearances of high-temperature turbomachinery.

Kaplan turbine tip vortex cavitation – analysis and prevention

International Nuclear Information System (INIS)

Motycak, L; Skotak, A; Kupcik, R

2012-01-01

The work is focused on one type of Kaplan turbine runner cavitation – a tip vortex cavitation. For detailed description of the tip vortex, the CFD analysis is used. On the basis of this analysis it is possible to estimate the intensity of cavitating vortex core, danger of possible blade surface and runner chamber cavitation pitting. In the paper, the ways how to avoid the pitting effect of the tip vortex are described. In order to prevent the blade surface against pitting, the following possibilities as the change of geometry of the runner blade, dimension of tip clearance and finally the installation of the anti-cavitation lips are discussed. The knowledge of the shape and intensity of the tip vortex helps to design the anti-cavitation lips more sophistically. After all, the results of the model tests of the Kaplan runner with or without anti-cavitation lips and the results of the CFD analysis are compared.

Stress corrosion crack tip microstructure in nickel-based alloys

International Nuclear Information System (INIS)

Shei, S.A.; Yang, W.J.

1994-04-01

Stress corrosion cracking behavior of several nickel-base alloys in high temperature caustic environments has been evaluated. The crack tip and fracture surfaces were examined using Auger/ESCA and Analytical Electron Microscopy (AEM) to determine the near crack tip microstructure and microchemistry. Results showed formation of chromium-rich oxides at or near the crack tip and nickel-rich de-alloying layers away from the crack tip. The stress corrosion resistance of different nickel-base alloys in caustic may be explained by the preferential oxidation and dissolution of different alloying elements at the crack tip. Alloy 600 (UNS N06600) shows good general corrosion and intergranular attack resistance in caustic because of its high nickel content. Thermally treated Alloy 690 (UNS N06690) and Alloy 600 provide good stress corrosion cracking resistance because of high chromium contents along grain boundaries. Alloy 625 (UNS N06625) does not show as good stress corrosion cracking resistance as Alloy 690 or Alloy 600 because of its high molybdenum content

LONG-TERM PRECONDITIONING OF PLANTLETS: A PRACTICAL METHOD FOR ENHANCING SURVIVAL OF PINEAPPLE (Ananas comosus Merr.) SHOOT TIPS CRYOPRESERVED USING VITRIFICATION.

Science.gov (United States)

Hu, W H; Liu, S F; Liaw, S I

2015-01-01

The purpose of this study was to develop an efficient cryopreservation protocol for pineapple (Ananas comosus Merr.) shoot tips. The optimal state of pineapple plantlets was investigated by using sucrose preconditioning to enhance survival after cryostorage. To achieve a suitable state of plantlets before cryopreservation, 0.2 M to 0.4 M sucrose concentrations combined with short- (0-7 days), medium- (15-30 days), and long-term (75-150 days) preconditioning periods were compared. The highest survival (100 %) was achieved using the following procedure: intact plantlets underwent long-term preconditioning with 0.2 M sucrose for 135 days, dissected shoot tips were treated with a loading solution containing 2.0 M glycerol + 0.4 M sucrose for 60 min at 25 degree and the shoot tips were dehydrated in PVS2 for 2h at 0 degree C before being plunged in liquid nitrogen. Rewarming was conducted in a water-bath for 30 s at 40 degree C and PVS2 was replaced with a 1.2 M sucrose solution for 30 min at 25 degree C. The shoot tips were transferred on semisolid medium and left in the dark for 1 week, then in dim light for 3 weeks.

Local measurement and numerical modeling of mass/heat transfer from a turbine blade in a linear cascade with tip clearance

Science.gov (United States)

Jin, Peitong

2000-11-01

Local mass/heat transfer measurements from the turbine blade near-tip and the tip surfaces are performed using the naphthalene sublimation technique. The experiments are conducted in a linear cascade consisting of five high-pressure blades with a central test-blade configuration. The incoming flow conditions are close to those of the gas turbine engine environment (boundary layer displacement thickness is about 0.01 of chord) with an exit Reynolds number of 6.2 x 105. The effects of tip clearance level (0.86%--6.90% of chord), mainstream Reynolds number and turbulence intensity (0.2 and 12.0%) are investigated. Two methods of flow visualization---oil and lampblack, laser light sheet smoke wire---as well as static pressure measurement on the blade surface are used to study the tip leakage flow and vortex in the cascade. In addition, numerical modeling of the flow and heat transfer processes in the linear cascade with different tip clearances is conducted using commercial software incorporating advanced turbulence models. The present study confirms many important results on the tip leakage flow and vortex from the literature, contributes to the current understanding in the effects of tip leakage flow and vortex on local heat transfer from the blade near-tip and the tip surfaces, and provides detailed local and average heat/mass transfer data applicable to turbine blade tip cooling design.

Life form succession in plant communities on colliery waste tips

Energy Technology Data Exchange (ETDEWEB)

Down, C G

1973-01-01

Five disused colliery waste tips in the Somerset Coalfield, 12, 15, 21, 55 and 98 years old, respectively, were examined to determine the life forms of the naturally-occurring vascular plant species. Hemicryptophytes comprised between 68 and 79% of the number of species on each tip. Rosette hemicryptophytes comprised 31.8% of the species on the 12-year tip, declining to 11.8% on the 98-year tip. It is suggested that artificial planting of rosette hemicryptophytes may be beneficial in reclamation schemes. 3 tables.

Search Tips: MedlinePlus

Science.gov (United States)

... of this page: https://medlineplus.gov/searchtips.html Search Tips To use the sharing features on this page, please enable JavaScript. How do I search MedlinePlus? The search box appears at the top ...

Identity and quantity of microorganisms in necrotising fasciitis determined by culture and molecular methods

DEFF Research Database (Denmark)

Rudkjøbing, Vibeke Børsholt; Thomsen, Trine Rolighed; Nielsen, Per Halkjær

communities were more common by molecular methods than culture. Correspondence between findings by culture and molecular methods indicates that the latter may be an appropriate method. The advantages of using molecular methods are: 1) identification of the pathogen(s) even when antibiotics have been...... involved in the disease may add to the knowledge of NF pathogenesis and influence the administration of antibiotics, thereby potentially improving the outcome for the patients. In this study the aim was to investigate the applicability of different molecular methods as compared to standard culture......-based methods. We investigated the microbial communities in 21 samples obtained during debridement of NF patients (n=8). Samples were examined by standard bacteriological examination (culture and microscopy) at Rigshospitalet (Copenhagen, Denmark) and a range of molecular methods. The best DNA extraction...

Thermo-mechanical analysis of FG nanobeam with attached tip mass: an exact solution

Science.gov (United States)

Ghadiri, Majid; Jafari, Ali

2016-12-01

Present disquisition proposes an analytical solution method for exploring the vibration characteristics of a cantilever functionally graded nanobeam with a concentrated mass exposed to thermal loading for the first time. Thermo-mechanical properties of FGM nanobeam are supposed to change through the thickness direction of beam based on the rule of power-law (P-FGM). The small-scale effect is taken into consideration based on nonlocal elasticity theory of Eringen. Linear temperature rise (LTR) through thickness direction is studied. Existence of centralized mass in the free end of nanobeam influences the mechanical and physical properties. Timoshenko beam theory is employed to derive the nonlocal governing equations and boundary conditions of FGM beam attached with a tip mass under temperature field via Hamilton's principle. An exact solution procedure is exploited to achieve the non-dimensional frequency of FG nanobeam exposed to temperature field with a tip mass. A parametric study is led to assess the efficacy of temperature changes, tip mass, small scale, beam thickness, power-law exponent, slenderness and thermal loading on the natural frequencies of FG cantilever nanobeam with a point mass at the free end. It is concluded that these parameters play remarkable roles on the dynamic behavior of FG nanobeam subjected to LTR with a tip mass. The results for simpler states are confirmed with known data in the literature. Presented numerical results can serve as benchmarks for future thermo-mechanical analyses of FG nanobeam with tip mass.

Restaurant Dining: Seven Tips for Staying Gluten Free

Science.gov (United States)

GiG Education Bulletin Restaurant Dining: Seven Tips for Staying Gluten-Free Updated May 2014 Tips for Dining Away from Home 1. Selection of ... a number of factors, including the type of restaurant you choose. • Be careful in restaurants where language ...

Incontinence Treatment: Dietary Tips

Science.gov (United States)

... helpful, please consider supporting IFFGD with a small tax-deductible donation. Lifestyle Changes Dietary Tips Medication Bowel ... arises requiring an expert’s care. © Copyright 1998-2018 International Foundation for Functional Gastrointestinal Disorders, Inc. (IFFGD). All ...

A numerical study of non-linear crack tip parameters

Directory of Open Access Journals (Sweden)

F.V. Antunes

2015-07-01

Full Text Available Crack closure concept has been widely used to explain different issues of fatigue crack propagation. However, different authors have questioned the relevance of crack closure and have proposed alternative concepts. The main objective here is to check the effectiveness of crack closure concept by linking the contact of crack flanks with non-linear crack tip parameters. Accordingly, 3D-FE numerical models with and without contact were developed for a wide range of loading scenarios and the crack tip parameters usually linked to fatigue crack growth, namely range of cyclic plastic strain, crack tip opening displacement, size of reversed plastic zone and total plastic dissipation per cycle, were investigated. It was demonstrated that: i LEFM concepts are applicable to the problem under study; ii the crack closure phenomenon has a great influence on crack tip parameters decreasing their values; iii the Keff concept is able to explain the variations of crack tip parameters produced by the contact of crack flanks; iv the analysis of remote compliance is the best numerical parameter to quantify the crack opening level; v without contact there is no effect of stress ratio on crack tip parameters. Therefore it is proved that the crack closure concept is valid.

A novel nano-hydroxyapatite – PMMA hybrid scaffolds adopted by conjugated thermal induced phase separation (TIPS) and wet-chemical approach: Analysis of its mechanical and biological properties

Energy Technology Data Exchange (ETDEWEB)

Radha, G. [National Centre for Nanoscience and Nanotechnology, University of Madras, Guindy campus, Chennai 600025 (India); Balakumar, S., E-mail: balasuga@yahoo.com [National Centre for Nanoscience and Nanotechnology, University of Madras, Guindy campus, Chennai 600025 (India); Venkatesan, Balaji; Vellaichamy, Elangovan [Department of Biochemistry, University of Madras, Guindy campus, Chennai 600025 (India)

2017-04-01

In this study, we report the preparation of nano-hydroxyapatite (nHAp) incorporated poly(methyl methacrylate) (PMMA) scaffolds by conjugated thermal induced phase separation (TIPS) and wet-chemical approach, which essentially facilitates the enhancement of both mechanical as well as biological properties of the scaffolds. The dissolution of PMMA was accomplished by acetone (Ace scaffold), ethanol-water (E-W scaffold) and isopropanol-water (I-W scaffold) mixtures as solvents. The existence of nHAp in PMMA matrix was investigated systematically. The porosity of ~ 57.89% was achieved from Ace scaffold that was higher degree compared to both I-W and E-W scaffolds. On the other hand, the dense porous architecture of I-W scaffold exhibited superior hardness of ~ 65.6 HR ‘D’ than that of the Ace and E-W scaffolds. All the fabricated samples demonstrated enhanced in vitro bioactivity with respect to increasing immersion period as a result of flower-like in vitro apatite layer formation. The MTT assay was carried out for 1 day and 3 day culture using Saos-2 osteoblast-like cells, which showed better cell proliferation with increasing culture period owing to the interconnected pore architecture of scaffolds and the rational hemocompatibility as per the ASTM standard F756-00. - Highlights: • Conjugated TIPS – wet chemical derived strategy was adopted for PMMA-nHAp composite scaffolds preparation. • TIPS method was carried out by varying solvents such as acetone, isopropanol-water and ethanol-water mixtures. • The impact of solvents on porosity and mechanical properties has been explored. • The existence of nHAp in PMMA has improved in-vitro bioactivity through apatitic-flowers formation. • Hemocompatibility of the scaffolds are in agreement with ASTM standards.

Influence of tip mass on dynamic behavior of cracked cantilever pipe conveying fluid with moving mass

International Nuclear Information System (INIS)

Yoon, Han Ik; Son, In Soo

2005-01-01

In this paper, we studied about the effect of the open crack and a tip mass on the dynamic behavior of a cantilever pipe conveying fluid with a moving mass. The equation of motion is derived by using Lagrange's equation and analyzed by numerical method. The cantilever pipe is modelled by the Euler-Bernoulli beam theory. The crack section is represented by a local flexibility matrix connecting two undamaged pipe segments. The influences of the crack, the moving mass, the tip mass and its moment of inertia, the velocity of fluid, and the coupling of these factors on the vibration mode, the frequency, and the tip-displacement of the cantilever pipe are analytically clarified

Transjugular Intrahepatic Portosystemic Shunt (TIPS): Current Status and Future Possibilities

International Nuclear Information System (INIS)

Bilbao, Jose Ignacio; Quiroga, Jorge; Herrero, Jose Ignacio; Benito, Alberto

2002-01-01

Since the insertion of the first TIPS in 1989 much has been learned about this therapeutic procedure. It has an established role for the treatment of some complications of portal hypertension: prevention of recurrent variceal bleeding and rescue of patients with acute uncontrollable variceal bleeding. In addition TIPS is useful for Budd-Chiari syndrome, refractory ascites and hepatorenal syndrome, although its specific role in these indications remains to be definitively established. However, the decrease in sinusoidal blood flow induced by TIPS can lead to the patient developing hepatic encephalopathy and liver failure in some cases. Therefore, TIPS should be used with caution in patients with very poor liver function. From a technical point of view, successful placement of TIPS is achieved in more than 98% of cases by experienced groups. At present, evaluation of TIPS dysfunction based on morphology probably leads to an overdiagnosis of this complication since most of these cases are not associated with clinical manifestations (recurrent bleeding or refractory ascites). The major disadvantage of TIPS remains its poor long-term patency requiring a mandatory surveillance program. The indicator for shunt function/malfunction should be the portosystemic pressure gradient, which is best assessed by intravascular measurements. Shunt obstructions may be prevented or reduced by the use of stent-grafts in the future

Ten Tips for Parents to Help Their Children Avoid Teen Pregnancy

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... we do » Resource library » Ten tips for parents Ten Tips for Parents to Help Their Children Avoid Teen Pregnancy Publication Created with Sketch. Ten Tips for Parents to Help Their Children Avoid ...

Robustness of tungsten single atom tips to thermal treatment and air exposure

Energy Technology Data Exchange (ETDEWEB)

Vesa, Cristian; Urban, Radovan [Department of Physics, University of Alberta, Edmonton, Alberta, Canada T6G 2G7 (Canada); National Institute for Nanotechnology, National Research Council of Canada, Edmonton, Alberta, Canada T6G 2M9 (Canada); Pitters, Jason L., E-mail: jason.pitters@nrc-cnrc.gc.ca [National Institute for Nanotechnology, National Research Council of Canada, Edmonton, Alberta, Canada T6G 2M9 (Canada); Wolkow, Robert A. [Department of Physics, University of Alberta, Edmonton, Alberta, Canada T6G 2G7 (Canada); National Institute for Nanotechnology, National Research Council of Canada, Edmonton, Alberta, Canada T6G 2M9 (Canada)

2014-05-01

Highlights: • W(1 1 1) single atom tips (SATs) were exposed to air. • SATs could be regenerated by field assisted chemical etching after exposure. • Warming procedures to minimize tip contamination were developed. • Degassing temperatures for air exposed tips were established. • Tip faceting occurred when SATs and unetched tips were annealed above 1200 °C. - Abstract: Experiments aimed at assessing the robustness of nitrogen-etched, single-atom tips (SATs) prepared using W(1 1 1) single crystal wire were performed. Our experiments showed that single-atoms tips sustain minimal damage when exposed to atmospheric conditions and can be readily and quickly nitrogen-etched to single-atom tips thereafter. The SATs can be annealed at temperatures up to 1100 °C with minimal shape changes. Moreover, annealing temperatures in excess of 1200 °C resulted in an apex faceting which may prove important in further single-atom tip creation. Procedures for warming of the SATs from operating temperatures of 80 K were also evaluated to determine conditions that limit tip contamination. These results show that SATS could be fabricated in a dedicated vacuum system and subsequently transferred to other instruments where they would undergo a brief conditioning procedure to recover the single-atom apex configuration prior to being subjected to operating conditions.

With Protein Foods, Variety Is Key: 10 Tips for Choosing Protein

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... Dietary Guidelines Communicator’s Guide 10 Tips: Vary Your Protein Routine You are here Home 10 Tips: Vary ... Protein Routine Print Share 10 Tips: Vary Your Protein Routine Protein foods include both animal (meat, poultry, ...

Axial compressor blade design for desensitization of aerodynamic performance and stability to tip clearance

Science.gov (United States)

Erler, Engin

Tip clearance flow is the flow through the clearance between the rotor blade tip and the shroud of a turbomachine, such as compressors and turbines. This flow is driven by the pressure difference across the blade (aerodynamic loading) in the tip region and is a major source of loss in performance and aerodynamic stability in axial compressors of modern aircraft engines. An increase in tip clearance, either temporary due to differential radial expansion between the blade and the shroud during transient operation or permanent due to engine wear or manufacturing tolerances on small blades, increases tip clearance flow and results in higher fuel consumption and higher risk of engine surge. A compressor design that can reduce the sensitivity of its performance and aerodynamic stability to tip clearance increase would have a major impact on short and long-term engine performance and operating envelope. While much research has been carried out on improving nominal compressor performance, little had been done on desensitization to tip clearance increase beyond isolated observations that certain blade designs such as forward chordwise sweep, seem to be less sensitive to tip clearance size increase. The current project aims to identify through a computational study the flow features and associated mechanisms that reduces sensitivity of axial compressor rotors to tip clearance size and propose blade design strategies that can exploit these results. The methodology starts with the design of a reference conventional axial compressor rotor followed by a parametric study with variations of this reference design through modification of the camber line and of the stacking line of blade profiles along the span. It is noted that a simple desensitization method would be to reduce the aerodynamic loading of the blade tip which would reduce the tip clearance flow and its proportional contribution to performance loss. However, with the larger part of the work on the flow done in this

TIPS Placement via Combined Transjugular and Transhepatic Approach for Cavernous Portal Vein Occlusion: Targeted Approach

Directory of Open Access Journals (Sweden)

Natanel Jourabchi

2013-01-01

Full Text Available Purpose. We report a novel technique which aided recanalization of an occluded portal vein for transjugular intrahepatic portosystemic shunt (TIPS creation in a patient with symptomatic portal vein thrombosis with cavernous transformation. Some have previously considered cavernous transformation a contraindication to TIPS. Case Presentation. 62-year-old man with chronic pancreatitis, portal vein thrombosis, portal hypertension and recurrent variceal bleeding presents with melena and hematemesis. The patient was severely anemic, hemodynamically unstable, and required emergent portal decompression. Attempts to recanalize the main portal vein using traditional transjugular access were unsuccessful. After percutaneous transhepatic right portal vein access and navigation of a wire through the occluded main portal vein, an angioplasty balloon was inflated at the desired site of shunt takeoff. The balloon was targeted and punctured from the transjugular approach, and a wire was passed into the portal system. TIPS placement then proceeded routinely. Conclusion. Although occlusion of the portal vein increases difficulty of performing TIPS, it should not be considered an absolute contraindication. We have described a method for recanalizing an occluded portal vein using a combined transhepatic and transjugular approach for TIPS. This approach may be useful to relieve portal hypertension in patients who fail endoscopic and/or surgical therapies.

The perceptions of employees towards tipping and motivation in the hotel industry

Directory of Open Access Journals (Sweden)

Kazembe Clotildah

2014-01-01

Full Text Available Restaurant tipping has been taken as a bone of contention which discriminates front and back employees involved with the service delivery in a hotel set- up. Monetary benefits affect worker motivation to some extent. Hence the study sought to analyze employee views on tipping and motivation. A lot of confusion and abhorrence has been created as to whom exactly should benefit from the tips servers get from guests. Qualitative research design was used to assess the extent to which tips are perceived as a reward for good service and how this influences worker motivation. Results showed that tipping is a two barreled tool where it can be a motivational tool to those who are tipped and a demotivator to those who are not tipped. The implication of the study is a service charge system to share tips is required to motivate all employees since the guest experience is a product of collective effort from almost all the employees in a hotel establishment.

MELD Score as a Predictor of Early Death in Patients Undergoing Elective Transjugular Intrahepatic Portosystemic Shunt (TIPS) Procedures

International Nuclear Information System (INIS)

Montgomery, Aaron; Ferral, Hector; Vasan, Rajiv; Postoak, Darren W.

2005-01-01

Purpose. To Evaluate the MELD score as a predictor of 30-day mortality in patients undergoing elective TIPS procedures. Methods. This was a retrospective, IRB-approved study. The medical records of all patients who underwent a TIPS procedure between May 1, 1999 and June 1, 2003 in a single institution were reviewed. Patients who underwent elective TIPS were selected. Elective TIPS was performed in 119 patients with a mean age of 55.1 (± 9.6) years. The MELD and Child-Pugh scores before TIPS, etiology of cirrhosis, portosystemic gradients before and after TIPS, procedure time, and procedural complications were obtained from the medical records. The MELD and Child-Pugh scores before TIPS were compared between the survivor group (SG) and the early death (EDG) group. The early death rate was calculated for MELD score subgroups (1-10, 11-17, 18-24, and >24). Data were analyzed using the Fisher exact test, chi-square test and independent-sample t-test. A p value of less than 0.05 was considered significant. Results. Technical success rate was 100%. The early death rate was 10.9% (13/119). The mean MELD scores before TIPS were 19.4 (± 5.9) (EDG) and 14 (± 4.2) (SG) (p = 0.025). The early death rate was highest in the pre-TIPS MELD > 24 subgroup. The Child-Pugh scores were 9.0 (± 1.6) (SG) and 9.8 ± 1.06 (EDG) (p 0.08). The mean portosystemic gradients before TIPS were 20.5 (± 7.7) mmHg (EDG) and 22.7 (± 7.3) (SG) (p > 1) and the mean portosystemic gradients after TIPS were 6.5 (± 3.5) (EDG) and 6.9 (± 2.4) (SG) (p > 1). The mean procedural times were 95.6 (± 8.4) min (EDG) and 89.2 (± 7.5) min (SG) (p > 1). No early death was attributed to a fatal complication during TIPS. Conclusion. The MELD score is useful in identifying patients at a higher risk of early death after an elective TIPS. On the basis of our results, we do not endorse elective TIPS in patients with MELD scores > 24

Tips for Starting Physical Activity

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... Legislative Information Advisory & Coordinating Committees Strategic Plans & Reports Research Areas FAQs ... Starting Physical Activity Related Topics Section Navigation Tips to Help You Get Active ...

DEFORMATION INFLUENCE ON A LIFETIME OF WELDING ELECTRODE TIPS

Directory of Open Access Journals (Sweden)

Ján Viňáš

2009-02-01

Full Text Available The contribution deals with the influence of welding electrode tips deformation on their lifetime. The influence of material properties, production technology and the intensity of welding electrodes load on their lifetime are presented. The electrode tips of the most used type of CuCr1Zr alloy of three basic standard shapes before and after the process of welding are evaluated. The process of welding is realized with low, middle and maximum welding parameters on programmable pneumatic spot welding machine VTS BPK 20. The influence of welding parameters on chosen material characteristics of welding tips is observed. Through the use of upsetting test, dependency of forming strength and deformation of material on used technology of welding tip production is observed.

Twelve tips for "flipping" the classroom.

Science.gov (United States)

Moffett, Jennifer

2015-04-01

The flipped classroom is a pedagogical model in which the typical lecture and homework elements of a course are reversed. The following tips outline the steps involved in making a successful transition to a flipped classroom approach. The tips are based on the available literature alongside the author's experience of using the approach in a medical education setting. Flipping a classroom has a number of potential benefits, for example increased educator-student interaction, but must be planned and implemented carefully to support effective learning.

Optical properties of a tip-induced quantum dot

NARCIS (Netherlands)

Kemerink, M.; Sauthoff, K.; Koenraad, P.M.; Gerritsen, J.W.; Kempen, van H.; Fomin, V.M.; Wolter, J.H.; Devreese, J.T.; Miura, N.; Ando, T.

2001-01-01

We have performed optical spectroscopy measurements on an STM-tip-induced quantum dot. The dominant confinement in the (hole) quantum dot is in the direction parallel to the tip axis. Electron confinement is achieved by a sub-surface AlGaAs barrier. Current dependent measurements indicate that

Aerodynamic effect of a honeycomb rotor tip shroud on a 50.8-centimeter-tip-diameter core turbine

Science.gov (United States)

Moffitt, T. P.; Whitney, W. J.

1983-01-01

A 50.8-cm-tip-diameter turbine equipped with a rotor tip shroud of hexagonal cell (or honeycomb) cross section has been tested in warm air (416 K) for a range of shroud coolant to primary flow rates. Test results were also obtained for the same turbine operated with a solid shroud for comparison. The results showed that the combined effect of the honeycomb shroud and the coolant flow was to cause a reduction of 2.8 points in efficiency at design speed, pressure ratio, and coolant flow rate. With the coolant system inactivated, the honeycomb shroud caused a decrease in efficiency of 2.3 points. These results and those obtained from a small reference turbine indicate that the dominant factor governing honeycomb tip shroud loss is the ratio of honeycomb depth to blade span. The loss results of the two shrouds could be correlated on this basis. The same honeycomb and coolant effects are expected to occur for the hot (2200 K) version of this turbine.

Precise Orientation of a Single C60 Molecule on the Tip of a Scanning Probe Microscope

Science.gov (United States)

Chiutu, C.; Sweetman, A. M.; Lakin, A. J.; Stannard, A.; Jarvis, S.; Kantorovich, L.; Dunn, J. L.; Moriarty, P.

2012-06-01

We show that the precise orientation of a C60 molecule which terminates the tip of a scanning probe microscope can be determined with atomic precision from submolecular contrast images of the fullerene cage. A comparison of experimental scanning tunneling microscopy data with images simulated using computationally inexpensive Hückel theory provides a robust method of identifying molecular rotation and tilt at the end of the probe microscope tip. Noncontact atomic force microscopy resolves the atoms of the C60 cage closest to the surface for a range of molecular orientations at tip-sample separations where the molecule-substrate interaction potential is weakly attractive. Measurements of the C60C60 pair potential acquired using a fullerene-terminated tip are in excellent agreement with theoretical predictions based on a pairwise summation of the van der Waals interactions between C atoms in each cage, i.e., the Girifalco potential [L. Girifalco, J. Phys. Chem. 95, 5370 (1991)JPCHAX0022-365410.1021/j100167a002].

Tip-enhanced Raman mapping with top-illumination AFM.

Science.gov (United States)

Chan, K L Andrew; Kazarian, Sergei G

2011-04-29

Tip-enhanced Raman mapping is a powerful, emerging technique that offers rich chemical information and high spatial resolution. Currently, most of the successes in tip-enhanced Raman scattering (TERS) measurements are based on the inverted configuration where tips and laser are approaching the sample from opposite sides. This results in the limitation of measurement for transparent samples only. Several approaches have been developed to obtain tip-enhanced Raman mapping in reflection mode, many of which involve certain customisations of the system. We have demonstrated in this work that it is also possible to obtain TERS nano-images using an upright microscope (top-illumination) with a gold-coated Si atomic force microscope (AFM) cantilever without significant modification to the existing integrated AFM/Raman system. A TERS image of a single-walled carbon nanotube has been achieved with a spatial resolution of ∼ 20-50 nm, demonstrating the potential of this technique for studying non-transparent nanoscale materials.

Tip-enhanced Raman mapping with top-illumination AFM

Energy Technology Data Exchange (ETDEWEB)

Chan, K L Andrew; Kazarian, Sergei G, E-mail: s.kazarian@imperial.ac.uk [Department of Chemical Engineering, Imperial College London, SW7 2AZ (United Kingdom)

2011-04-29

Tip-enhanced Raman mapping is a powerful, emerging technique that offers rich chemical information and high spatial resolution. Currently, most of the successes in tip-enhanced Raman scattering (TERS) measurements are based on the inverted configuration where tips and laser are approaching the sample from opposite sides. This results in the limitation of measurement for transparent samples only. Several approaches have been developed to obtain tip-enhanced Raman mapping in reflection mode, many of which involve certain customisations of the system. We have demonstrated in this work that it is also possible to obtain TERS nano-images using an upright microscope (top-illumination) with a gold-coated Si atomic force microscope (AFM) cantilever without significant modification to the existing integrated AFM/Raman system. A TERS image of a single-walled carbon nanotube has been achieved with a spatial resolution of {approx} 20-50 nm, demonstrating the potential of this technique for studying non-transparent nanoscale materials.

Tip-enhanced Raman mapping with top-illumination AFM

International Nuclear Information System (INIS)

Chan, K L Andrew; Kazarian, Sergei G

2011-01-01

Tip-enhanced Raman mapping is a powerful, emerging technique that offers rich chemical information and high spatial resolution. Currently, most of the successes in tip-enhanced Raman scattering (TERS) measurements are based on the inverted configuration where tips and laser are approaching the sample from opposite sides. This results in the limitation of measurement for transparent samples only. Several approaches have been developed to obtain tip-enhanced Raman mapping in reflection mode, many of which involve certain customisations of the system. We have demonstrated in this work that it is also possible to obtain TERS nano-images using an upright microscope (top-illumination) with a gold-coated Si atomic force microscope (AFM) cantilever without significant modification to the existing integrated AFM/Raman system. A TERS image of a single-walled carbon nanotube has been achieved with a spatial resolution of ∼ 20-50 nm, demonstrating the potential of this technique for studying non-transparent nanoscale materials.

29 CFR 531.52 - General characteristics of “tips.”

Science.gov (United States)

2010-07-01

... 29 Labor 3 2010-07-01 2010-07-01 false General characteristics of âtips.â 531.52 Section 531.52 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR REGULATIONS... Employees § 531.52 General characteristics of “tips.” A tip is a sum presented by a customer as a gift or...

Electron beam fabrication and characterization of high-resolution magnetic force microscopy tips

Science.gov (United States)

Rührig, M.; Porthun, S.; Lodder, J. C.; McVitie, S.; Heyderman, L. J.; Johnston, A. B.; Chapman, J. N.

1996-03-01

The stray field, magnetic microstructure, and switching behavior of high-resolution electron beam fabricated thin film tips for magnetic force microscopy (MFM) are investigated with different imaging modes in a transmission electron microscope (TEM). As the tiny smooth carbon needles covered with a thermally evaporated magnetic thin film are transparent to the electron energies used in these TEMs it is possible to observe both the external stray field emanating from the tips as well as their internal domain structure. The experiments confirm the basic features of electron beam fabricated thin film tips concluded from various MFM observations using these tips. Only a weak but highly concentrated stray field is observed emanating from the immediate apex region of the tip, consistent with their capability for high resolution. It also supports the negligible perturbation of the magnetization sample due to the tip stray field observed in MFM experiments. Investigation of the magnetization distributions within the tips, as well as preliminary magnetizing experiments, confirm a preferred single domain state of the high aspect ratio tips. To exclude artefacts of the observation techniques both nonmagnetic tips and those supporting different magnetization states are used for comparison.

A numerical study of crack tip constraint in ductile single crystals

Science.gov (United States)

Patil, Swapnil D.; Narasimhan, R.; Mishra, R. K.

In this work, the effect of crack tip constraint on near-tip stress and deformation fields in a ductile FCC single crystal is studied under mode I, plane strain conditions. To this end, modified boundary layer simulations within crystal plasticity framework are performed, neglecting elastic anisotropy. The first and second terms of the isotropic elastic crack tip field, which are governed by the stress intensity factor K and T-stress, are prescribed as remote boundary conditions and solutions pertaining to different levels of T-stress are generated. It is found that the near-tip deformation field, especially, the development of kink or slip shear bands, is sensitive to the constraint level. The stress distribution and the size and shape of the plastic zone near the crack tip are also strongly influenced by the level of T-stress, with progressive loss of crack tip constraint occurring as T-stress becomes more negative. A family of near-tip fields is obtained which are characterized by two terms (such as K and T or J and a constraint parameter Q) as in isotropic plastic solids.

Fabrication of tungsten tip for scanning tunneling microscope by the lever principle

International Nuclear Information System (INIS)

Wang Yang; Wang Huabin; Chinese Academy of Sciences, Beijing; Gong Jinlong; Zhu Dezhang

2007-01-01

A novel experimental setup was designed to fabricate tungsten tips for scanning tunneling microscope (STM), based on simple mechanical lever principle. The equipment can quickly separate the tip from electrolyte to avoid the further etching of the fine-shaped tungsten tip. The setup is advantageous for its simplicity over complex electronic control systems. The use result in scanning electron microscope demonstrates that the radius of the tip can reach 50 nm. The tip was applied to scan the surface of highly-oriented pyrolytic graphite, and the results were satisfactory. It is shown that the tip can be used for the scanning of atomically resolved images. (authors)

A method for isolating identifying and culturing of rat trachea-bronchia epithelial cells

International Nuclear Information System (INIS)

Cui Fengmei; Su Shibiao; Nie Jihua; Li Bingyan; Tong Jian

2005-01-01

Objective: To explore a method for isolating identifying and culturing the rat trachea-bronchia epithelial cells. Methods: The rat trachea-bronchia epithelial cells were isolated by digestion with pronase and brushing with cell brush, identified using confocul and cultured in entire F12 media with no serum. Results: With this method, cells in high purity and high viability could be obtained, and about 10 6 cells per rat. The cells grow well in entire F12 media with no serum. Conclusion: The method is useful for isolating rate trachea-bronchia epithelial cells and the entire F12 media with no serum is effective for culturing. (authors)

Lateral and vertical manipulations of single atoms on the Ag(1 1 1) surface with the copper single-atom and trimer-apex tips

International Nuclear Information System (INIS)

Xie Yiqun; Yang Tianxing; Ye Xiang; Huang Lei

2011-01-01

We study the lateral and vertical manipulations of single Ag and Cu atoms on the Ag(1 1 1) surface with the Cu single-atom and trimer-apex tips using molecular statics simulations. The reliability of the lateral manipulation with the Cu single-atom tip is investigated, and compared with that for the Ag tips. We find that overall the manipulation reliability (MR) increases with the decreasing tip height, and in a wide tip-height range the MR is better than those for both the Ag single-atom and trimer-apex tips. This is due to the stronger attractive force of the Cu tip and its better stability against the interactions with the Ag surface. With the Cu trimer-apex tip, the single Ag and Cu adatoms can be picked up from the flat Ag(1 1 1) surface, and moreover a reversible vertical manipulation of single Ag atoms on the stepped Ag(1 1 1) surface is possible, suggesting a method to modify two-dimensional Ag nanostructures on the Ag(1 1 1) surface with the Cu trimer-apex tip.

Tipping elements in the Arctic marine ecosystem.

Science.gov (United States)

Duarte, Carlos M; Agustí, Susana; Wassmann, Paul; Arrieta, Jesús M; Alcaraz, Miquel; Coello, Alexandra; Marbà, Núria; Hendriks, Iris E; Holding, Johnna; García-Zarandona, Iñigo; Kritzberg, Emma; Vaqué, Dolors

2012-02-01

The Arctic marine ecosystem contains multiple elements that present alternative states. The most obvious of which is an Arctic Ocean largely covered by an ice sheet in summer versus one largely devoid of such cover. Ecosystems under pressure typically shift between such alternative states in an abrupt, rather than smooth manner, with the level of forcing required for shifting this status termed threshold or tipping point. Loss of Arctic ice due to anthropogenic climate change is accelerating, with the extent of Arctic sea ice displaying increased variance at present, a leading indicator of the proximity of a possible tipping point. Reduced ice extent is expected, in turn, to trigger a number of additional tipping elements, physical, chemical, and biological, in motion, with potentially large impacts on the Arctic marine ecosystem.

Bacterial diversity associated with the rotifer Brachionus plicatilis sp. complex determined by culture-dependent and -independent methods.

Science.gov (United States)

Ishino, Ryota; Iehata, Shunpei; Nakano, Miyo; Tanaka, Reiji; Yoshimatsu, Takao; Maeda, Hiroto

2012-03-01

The bacterial communities associated with rotifers (Brachionus plicatilis sp. complex) and their culture water were determined using culture-dependent and -independent methods (16S rRNA gene clone library). The bacterial communities determined by the culture-independent method were more diverse than those determined by the culture-dependent method. Although the culture-dependent method indicated the bacterial community of rotifers was relatively similar to that of the culture water, 16S rRNA gene clone library analyses revealed a great difference between the two microbiotas. Our results suggest that most bacteria associated with rotifers are not easily cultured using conventional methods, and that the microbiota of rotifers do not correspond with that of the culture water completely.

Sports Dehydration Safety Tips

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Sports Dehydration Safety Tips Everything you need to know to keep your kids safe from dehydration when playing sports. To keep kids in top ... to stay hydrated by drinking plenty of fluids. Dehydration occurs when a body loses more water than ...

Anisotropic Adhesion Properties of Triangular-Tip-Shaped Micropillars

KAUST Repository

Kwak, Moon Kyu

2011-06-01

Directional dry adhesive microstructures consisting of high-density triangular-tip-shaped micropillars are described. The wide-tip structures allow for unique directional shear adhesion properties with respect to the peeling direction, along with relatively high normal adhesion. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Anisotropic Adhesion Properties of Triangular-Tip-Shaped Micropillars

KAUST Repository

Kwak, Moon Kyu; Jeong, Hoon Eui; Bae, Won Gyu; Jung, Ho-Sup; Suh, Kahp Y.

2011-01-01

Directional dry adhesive microstructures consisting of high-density triangular-tip-shaped micropillars are described. The wide-tip structures allow for unique directional shear adhesion properties with respect to the peeling direction, along with relatively high normal adhesion. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Defining tipping points for social-ecological systems scholarship—an interdisciplinary literature review

Science.gov (United States)

Milkoreit, Manjana; Hodbod, Jennifer; Baggio, Jacopo; Benessaiah, Karina; Calderón-Contreras, Rafael; Donges, Jonathan F.; Mathias, Jean-Denis; Rocha, Juan Carlos; Schoon, Michael; Werners, Saskia E.

2018-03-01

The term tipping point has experienced explosive popularity across multiple disciplines over the last decade. Research on social-ecological systems (SES) has contributed to the growth and diversity of the term’s use. The diverse uses of the term obscure potential differences between tipping behavior in natural and social systems, and issues of causality across natural and social system components in SES. This paper aims to create the foundation for a discussion within the SES research community about the appropriate use of the term tipping point, especially the relatively novel term ‘social tipping point.’ We review existing literature on tipping points and similar concepts (e.g. regime shifts, critical transitions) across all spheres of science published between 1960 and 2016 with a special focus on a recent and still small body of work on social tipping points. We combine quantitative and qualitative analyses in a bibliometric approach, rooted in an expert elicitation process. We find that the term tipping point became popular after the year 2000—long after the terms regime shift and critical transition—across all spheres of science. We identify 23 distinct features of tipping point definitions and their prevalence across disciplines, but find no clear taxonomy of discipline-specific definitions. Building on the most frequently used features, we propose definitions for tipping points in general and social tipping points in SES in particular.

Heat Transfer Characteristics on the Squealer Tip of gas turbine blade in a linear cascade

International Nuclear Information System (INIS)

Lee, Woo Jin; Lee, Dong Hyun; Kim, Kyung Min; Cho, Hyung Hee; Lee, Dong Ho; Kang, Shin Hyoung

2007-01-01