High sensitivity and high Q-factor nanoslotted parallel quadrabeam photonic crystal cavity for real-time and label-free sensing

Energy Technology Data Exchange (ETDEWEB)

Yang, Daquan [Rowland Institute at Harvard University, Cambridge, Massachusetts 02142 (United States); State Key Laboratory of Information Photonics and Optical Communications, School of Information and Communication Engineering, Beijing University of Posts and Telecommunications, Beijing 100876 (China); School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138 (United States); Kita, Shota; Wang, Cheng; Lončar, Marko [School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138 (United States); Liang, Feng; Quan, Qimin [Rowland Institute at Harvard University, Cambridge, Massachusetts 02142 (United States); Tian, Huiping; Ji, Yuefeng [State Key Laboratory of Information Photonics and Optical Communications, School of Information and Communication Engineering, Beijing University of Posts and Telecommunications, Beijing 100876 (China)

2014-08-11

We experimentally demonstrate a label-free sensor based on nanoslotted parallel quadrabeam photonic crystal cavity (NPQC). The NPQC possesses both high sensitivity and high Q-factor. We achieved sensitivity (S) of 451 nm/refractive index unit and Q-factor >7000 in water at telecom wavelength range, featuring a sensor figure of merit >2000, an order of magnitude improvement over the previous photonic crystal sensors. In addition, we measured the streptavidin-biotin binding affinity and detected 10 ag/mL concentrated streptavidin in the phosphate buffered saline solution.

High-Resolution Ultrasound-Switchable Fluorescence Imaging in Centimeter-Deep Tissue Phantoms with High Signal-To-Noise Ratio and High Sensitivity via Novel Contrast Agents.

Science.gov (United States)

Cheng, Bingbing; Bandi, Venugopal; Wei, Ming-Yuan; Pei, Yanbo; D'Souza, Francis; Nguyen, Kytai T; Hong, Yi; Yuan, Baohong

2016-01-01

For many years, investigators have sought after high-resolution fluorescence imaging in centimeter-deep tissue because many interesting in vivo phenomena-such as the presence of immune system cells, tumor angiogenesis, and metastasis-may be located deep in tissue. Previously, we developed a new imaging technique to achieve high spatial resolution in sub-centimeter deep tissue phantoms named continuous-wave ultrasound-switchable fluorescence (CW-USF). The principle is to use a focused ultrasound wave to externally and locally switch on and off the fluorophore emission from a small volume (close to ultrasound focal volume). By making improvements in three aspects of this technique: excellent near-infrared USF contrast agents, a sensitive frequency-domain USF imaging system, and an effective signal processing algorithm, for the first time this study has achieved high spatial resolution (~ 900 μm) in 3-centimeter-deep tissue phantoms with high signal-to-noise ratio (SNR) and high sensitivity (3.4 picomoles of fluorophore in a volume of 68 nanoliters can be detected). We have achieved these results in both tissue-mimic phantoms and porcine muscle tissues. We have also demonstrated multi-color USF to image and distinguish two fluorophores with different wavelengths, which might be very useful for simultaneously imaging of multiple targets and observing their interactions in the future. This work has opened the door for future studies of high-resolution centimeter-deep tissue fluorescence imaging.

A highly sensitive CMOS digital Hall sensor for low magnetic field applications.

Science.gov (United States)

Xu, Yue; Pan, Hong-Bin; He, Shu-Zhuan; Li, Li

2012-01-01

Integrated CMOS Hall sensors have been widely used to measure magnetic fields. However, they are difficult to work with in a low magnetic field environment due to their low sensitivity and large offset. This paper describes a highly sensitive digital Hall sensor fabricated in 0.18 μm high voltage CMOS technology for low field applications. The sensor consists of a switched cross-shaped Hall plate and a novel signal conditioner. It effectively eliminates offset and low frequency 1/f noise by applying a dynamic quadrature offset cancellation technique. The measured results show the optimal Hall plate achieves a high current related sensitivity of about 310 V/AT. The whole sensor has a remarkable ability to measure a minimum ± 2 mT magnetic field and output a digital Hall signal in a wide temperature range from -40 °C to 120 °C.

Development of high sensitivity and high speed large size blank inspection system LBIS

Science.gov (United States)

Ohara, Shinobu; Yoshida, Akinori; Hirai, Mitsuo; Kato, Takenori; Moriizumi, Koichi; Kusunose, Haruhiko

2017-07-01

The production of high-resolution flat panel displays (FPDs) for mobile phones today requires the use of high-quality large-size photomasks (LSPMs). Organic light emitting diode (OLED) displays use several transistors on each pixel for precise current control and, as such, the mask patterns for OLED displays are denser and finer than the patterns for the previous generation displays throughout the entire mask surface. It is therefore strongly demanded that mask patterns be produced with high fidelity and free of defect. To enable the production of a high quality LSPM in a short lead time, the manufacturers need a high-sensitivity high-speed mask blank inspection system that meets the requirement of advanced LSPMs. Lasertec has developed a large-size blank inspection system called LBIS, which achieves high sensitivity based on a laser-scattering technique. LBIS employs a high power laser as its inspection light source. LBIS's delivery optics, including a scanner and F-Theta scan lens, focus the light from the source linearly on the surface of the blank. Its specially-designed optics collect the light scattered by particles and defects generated during the manufacturing process, such as scratches, on the surface and guide it to photo multiplier tubes (PMTs) with high efficiency. Multiple PMTs are used on LBIS for the stable detection of scattered light, which may be distributed at various angles due to irregular shapes of defects. LBIS captures 0.3mμ PSL at a detection rate of over 99.5% with uniform sensitivity. Its inspection time is 20 minutes for a G8 blank and 35 minutes for G10. The differential interference contrast (DIC) microscope on the inspection head of LBIS captures high-contrast review images after inspection. The images are classified automatically.

Confidentiality Enhancement of Highly Sensitive Nuclear Data Using Steganography with Chaotic Encryption over OFDM Channel

International Nuclear Information System (INIS)

Mahmoud, S.; Ayad, N.; Elsayed, F.; Elbendary, M.

2016-01-01

Full text: Due to the widespread usage of the internet and other wired and wireless communication methods, the security of the transmitted data has become a major requirement. Nuclear knowledge is mainly built upon the exchange of nuclear information which is considered highly sensitive information, so its security has to be enhanced by using high level security mechanisms. Data confidentiality is concerned with the achievement of higher protection for confidential information from unauthorized disclosure or access. Cryptography and steganography are famous and widely used techniques that process information in order to achieve its confidentiality, but sometimes, when used individually, they don’t satisfy a required level of security for highly sensitive data. In this paper, cryptography is accompanied with steganography for constituting a multilayer security techniques that can strengthen the level of security of highly confidential nuclear data that are archived or transmitted through different channel types and noise conditions. (author)

Polarization-sensitive and broadband germanium sulfide photodetectors with excellent high-temperature performance.

Science.gov (United States)

Tan, Dezhi; Zhang, Wenjin; Wang, Xiaofan; Koirala, Sandhaya; Miyauchi, Yuhei; Matsuda, Kazunari

2017-08-31

Layered materials, such as graphene, transition metal dichalcogenides and black phosphorene, have been established rapidly as intriguing building blocks for optoelectronic devices. Here, we introduce highly polarization sensitive, broadband, and high-temperature-operation photodetectors based on multilayer germanium sulfide (GeS). The GeS photodetector shows a high photoresponsivity of about 6.8 × 10 3 A W -1 , an extremely high specific detectivity of 5.6 × 10 14 Jones, and broad spectral response in the wavelength range of 300-800 nm. More importantly, the GeS photodetector has high polarization sensitivity to incident linearly polarized light, which provides another degree of freedom for photodetectors. Tremendously enhanced photoresponsivity is observed with a temperature increase, and high responsivity is achievable at least up to 423 K. The establishment of larger photoinduced reduction of the Schottky barrier height will be significant for the investigation of the photoresponse mechanism of 2D layered material-based photodetectors. These attributes of high photocurrent generation in a wide temperature range, broad spectral response, and polarization sensitivity coupled with environmental stability indicate that the proposed GeS photodetector is very suitable for optoelectronic applications.

Compton imaging with a highly-segmented, position-sensitive HPGe detector

Energy Technology Data Exchange (ETDEWEB)

Steinbach, T.; Hirsch, R.; Reiter, P.; Birkenbach, B.; Bruyneel, B.; Eberth, J.; Hess, H.; Lewandowski, L. [Universitaet zu Koeln, Institut fuer Kernphysik, Koeln (Germany); Gernhaeuser, R.; Maier, L.; Schlarb, M.; Weiler, B.; Winkel, M. [Technische Universitaet Muenchen, Physik Department, Garching (Germany)

2017-02-15

A Compton camera based on a highly-segmented high-purity germanium (HPGe) detector and a double-sided silicon-strip detector (DSSD) was developed, tested, and put into operation; the origin of γ radiation was determined successfully. The Compton camera is operated in two different modes. Coincidences from Compton-scattered γ-ray events between DSSD and HPGe detector allow for best angular resolution; while the high-efficiency mode takes advantage of the position sensitivity of the highly-segmented HPGe detector. In this mode the setup is sensitive to the whole 4π solid angle. The interaction-point positions in the 36-fold segmented large-volume HPGe detector are determined by pulse-shape analysis (PSA) of all HPGe detector signals. Imaging algorithms were developed for each mode and successfully implemented. The angular resolution sensitively depends on parameters such as geometry, selected multiplicity and interaction-point distances. Best results were obtained taking into account the crosstalk properties, the time alignment of the signals and the distance metric for the PSA for both operation modes. An angular resolution between 13.8 {sup circle} and 19.1 {sup circle}, depending on the minimal interaction-point distance for the high-efficiency mode at an energy of 1275 keV, was achieved. In the coincidence mode, an increased angular resolution of 4.6 {sup circle} was determined for the same γ-ray energy. (orig.)

Chemically Designed Metallic/Insulating Hybrid Nanostructures with Silver Nanocrystals for Highly Sensitive Wearable Pressure Sensors.

Science.gov (United States)

Kim, Haneun; Lee, Seung-Wook; Joh, Hyungmok; Seong, Mingi; Lee, Woo Seok; Kang, Min Su; Pyo, Jun Beom; Oh, Soong Ju

2018-01-10

With the increase in interest in wearable tactile pressure sensors for e-skin, researches to make nanostructures to achieve high sensitivity have been actively conducted. However, limitations such as complex fabrication processes using expensive equipment still exist. Herein, simple lithography-free techniques to develop pyramid-like metal/insulator hybrid nanostructures utilizing nanocrystals (NCs) are demonstrated. Ligand-exchanged and unexchanged silver NC thin films are used as metallic and insulating components, respectively. The interfaces of each NC layer are chemically engineered to create discontinuous insulating layers, i.e., spacers for improved sensitivity, and eventually to realize fully solution-processed pressure sensors. Device performance analysis with structural, chemical, and electronic characterization and conductive atomic force microscopy study reveals that hybrid nanostructure based pressure sensor shows an enhanced sensitivity of higher than 500 kPa -1 , reliability, and low power consumption with a wide range of pressure sensing. Nano-/micro-hierarchical structures are also designed by combining hybrid nanostructures with conventional microstructures, exhibiting further enhanced sensing range and achieving a record sensitivity of 2.72 × 10 4 kPa -1 . Finally, all-solution-processed pressure sensor arrays with high pixel density, capable of detecting delicate signals with high spatial selectivity much better than the human tactile threshold, are introduced.

Integration of a highly ordered gold nanowires array with glucose oxidase for ultra-sensitive glucose detection

Energy Technology Data Exchange (ETDEWEB)

Cui, Jiewu [NanoScience and Sensor Technology Research Group, School of Applied Sciences and Engineering, Monash University, Gippsland Campus, Churchill 3842, VIC Australia (Australia); Laboratory of Functional Nanomaterials and Devices, School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009, Anhui (China); Adeloju, Samuel B., E-mail: sam.adeloju@monash.edu [NanoScience and Sensor Technology Research Group, School of Applied Sciences and Engineering, Monash University, Gippsland Campus, Churchill 3842, VIC Australia (Australia); Wu, Yucheng, E-mail: ycwu@hfut.edu.cn [Laboratory of Functional Nanomaterials and Devices, School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009, Anhui (China)

2014-01-27

Graphical abstract: -- Highlights: •Successfully synthesised highly-ordered gold nanowires array with an AAO template. •Fabricated an ultra-sensitive glucose nanobiosensor with the gold nanowires array. •Achieved sensitivity as high as 379.0 μA cm{sup −2} mM{sup −1} and detection limit as low as 50 nM. •Achieved excellent anti-interference with aid of Nafion membrane towards UA and AA. •Enabled successful detection and quantification of glucose in human blood serum. -- Abstract: A highly sensitive amperometric nanobiosensor has been developed by integration of glucose oxidase (GO{sub x}) with a gold nanowires array (AuNWA) by cross-linking with a mixture of glutaraldehyde (GLA) and bovine serum albumin (BSA). An initial investigation of the morphology of the synthesized AuNWA by field emission scanning electron microscopy (FESEM) and field emission transmission electron microscopy (FETEM) revealed that the nanowires array was highly ordered with rough surface, and the electrochemical features of the AuNWA with/without modification were also investigated. The integrated AuNWA–BSA–GLA–GO{sub x} nanobiosensor with Nafion membrane gave a very high sensitivity of 298.2 μA cm{sup −2} mM{sup −1} for amperometric detection of glucose, while also achieving a low detection limit of 0.1 μM, and a wide linear range of 5–6000 μM. Furthermore, the nanobiosensor exhibited excellent anti-interference ability towards uric acid (UA) and ascorbic acid (AA) with the aid of Nafion membrane, and the results obtained for the analysis of human blood serum indicated that the device is capable of glucose detection in real samples.

Highly Sensitive Flexible Magnetic Sensor Based on Anisotropic Magnetoresistance Effect.

Science.gov (United States)

Wang, Zhiguang; Wang, Xinjun; Li, Menghui; Gao, Yuan; Hu, Zhongqiang; Nan, Tianxiang; Liang, Xianfeng; Chen, Huaihao; Yang, Jia; Cash, Syd; Sun, Nian-Xiang

2016-11-01

A highly sensitive flexible magnetic sensor based on the anisotropic magnetoresistance effect is fabricated. A limit of detection of 150 nT is observed and excellent deformation stability is achieved after wrapping of the flexible sensor, with bending radii down to 5 mm. The flexible AMR sensor is used to read a magnetic pattern with a thickness of 10 μm that is formed by ferrite magnetic inks. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Multiplex enrichment quantitative PCR (ME-qPCR): a high-throughput, highly sensitive detection method for GMO identification.

Science.gov (United States)

Fu, Wei; Zhu, Pengyu; Wei, Shuang; Zhixin, Du; Wang, Chenguang; Wu, Xiyang; Li, Feiwu; Zhu, Shuifang

2017-04-01

Among all of the high-throughput detection methods, PCR-based methodologies are regarded as the most cost-efficient and feasible methodologies compared with the next-generation sequencing or ChIP-based methods. However, the PCR-based methods can only achieve multiplex detection up to 15-plex due to limitations imposed by the multiplex primer interactions. The detection throughput cannot meet the demands of high-throughput detection, such as SNP or gene expression analysis. Therefore, in our study, we have developed a new high-throughput PCR-based detection method, multiplex enrichment quantitative PCR (ME-qPCR), which is a combination of qPCR and nested PCR. The GMO content detection results in our study showed that ME-qPCR could achieve high-throughput detection up to 26-plex. Compared to the original qPCR, the Ct values of ME-qPCR were lower for the same group, which showed that ME-qPCR sensitivity is higher than the original qPCR. The absolute limit of detection for ME-qPCR could achieve levels as low as a single copy of the plant genome. Moreover, the specificity results showed that no cross-amplification occurred for irrelevant GMO events. After evaluation of all of the parameters, a practical evaluation was performed with different foods. The more stable amplification results, compared to qPCR, showed that ME-qPCR was suitable for GMO detection in foods. In conclusion, ME-qPCR achieved sensitive, high-throughput GMO detection in complex substrates, such as crops or food samples. In the future, ME-qPCR-based GMO content identification may positively impact SNP analysis or multiplex gene expression of food or agricultural samples. Graphical abstract For the first-step amplification, four primers (A, B, C, and D) have been added into the reaction volume. In this manner, four kinds of amplicons have been generated. All of these four amplicons could be regarded as the target of second-step PCR. For the second-step amplification, three parallels have been taken for

A simple, tunable, and highly sensitive radio-frequency sensor.

Science.gov (United States)

Cui, Yan; Sun, Jiwei; He, Yuxi; Wang, Zheng; Wang, Pingshan

2013-08-05

We report a radio frequency (RF) sensor that exploits tunable attenuators and phase shifters to achieve high-sensitivity and broad band frequency tunability. Three frequency bands are combined to enable sensor operations from ∼20 MHz to ∼38 GHz. The effective quality factor ( Q eff ) of the sensor is as high as ∼3.8 × 10 6 with 200  μ l of water samples. We also demonstrate the measurement of 2-proponal-water-solution permittivity at 0.01 mole concentration level from ∼1 GHz to ∼10 GHz. Methanol-water solution and de-ionized water are used to calibrate the RF sensor for the quantitative measurements.

Quartz crystal microbalance-based system for high-sensitivity differential sputter yield measurements

International Nuclear Information System (INIS)

Rubin, B.; Topper, J. L.; Farnell, C. C.; Yalin, A. P.

2009-01-01

We present a quartz crystal microbalance-based system for high sensitivity differential sputter yield measurements of different target materials due to ion bombardment. The differential sputter yields can be integrated to find total yields. Possible ion beam conditions include ion energies in the range of 30-350 eV and incidence angles of 0 deg. - 70 deg. from normal. A four-grid ion optics system is used to achieve a collimated ion beam at low energy (<100 eV) and a two-grid ion optics is used for higher energies (up to 750 eV). A complementary weight loss approach is also used to measure total sputter yields. Validation experiments are presented that confirm high sensitivity and accuracy of sputter yield measurements.

High order depletion sensitivity analysis

International Nuclear Information System (INIS)

Naguib, K.; Adib, M.; Morcos, H.N.

2002-01-01

A high order depletion sensitivity method was applied to calculate the sensitivities of build-up of actinides in the irradiated fuel due to cross-section uncertainties. An iteration method based on Taylor series expansion was applied to construct stationary principle, from which all orders of perturbations were calculated. The irradiated EK-10 and MTR-20 fuels at their maximum burn-up of 25% and 65% respectively were considered for sensitivity analysis. The results of calculation show that, in case of EK-10 fuel (low burn-up), the first order sensitivity was found to be enough to perform an accuracy of 1%. While in case of MTR-20 (high burn-up) the fifth order was found to provide 3% accuracy. A computer code SENS was developed to provide the required calculations

Towards highly sensitive strain sensing based on nanostructured materials

International Nuclear Information System (INIS)

Dao, Dzung Viet; Nakamura, Koichi; Sugiyama, Susumu; Bui, Tung Thanh; Dau, Van Thanh; Yamada, Takeo; Hata, Kenji

2010-01-01

This paper presents our recent theoretical and experimental study of piezo-effects in nanostructured materials for highly sensitive, high resolution mechanical sensors. The piezo-effects presented here include the piezoresistive effect in a silicon nanowire (SiNW) and single wall carbon nanotube (SWCNT) thin film, as well as the piezo-optic effect in a Si photonic crystal (PhC) nanocavity. Firstly, the electronic energy band structure of the silicon nanostructure is discussed and simulated by using the First-Principles Calculations method. The result showed a remarkably different energy band structure compared with that of bulk silicon. This difference in the electronic state will result in different physical, chemical, and therefore, sensing properties of silicon nanostructures. The piezoresistive effects of SiNW and SWCNT thin film were investigated experimentally. We found that, when the width of ( 110 ) p-type SiNW decreases from 500 to 35 nm, the piezoresistive effect increases by more than 60%. The longitudinal piezoresistive coefficient of SWCNT thin film was measured to be twice that of bulk p-type silicon. Finally, theoretical investigations of the piezo-optic effect in a PhC nanocavity based on Finite Difference Time Domain (FDTD) showed extremely high resolution strain sensing. These nanostructures were fabricated based on top-down nanofabrication technology. The achievements of this work are significant for highly sensitive, high resolution and miniaturized mechanical sensors

What factors determine academic achievement in high achieving undergraduate medical students? A qualitative study.

Science.gov (United States)

Abdulghani, Hamza M; Al-Drees, Abdulmajeed A; Khalil, Mahmood S; Ahmad, Farah; Ponnamperuma, Gominda G; Amin, Zubair

2014-04-01

Medical students' academic achievement is affected by many factors such as motivational beliefs and emotions. Although students with high intellectual capacity are selected to study medicine, their academic performance varies widely. The aim of this study is to explore the high achieving students' perceptions of factors contributing to academic achievement. Focus group discussions (FGD) were carried out with 10 male and 9 female high achieving (scores more than 85% in all tests) students, from the second, third, fourth and fifth academic years. During the FGDs, the students were encouraged to reflect on their learning strategies and activities. The discussion was audio-recorded, transcribed and analysed qualitatively. Factors influencing high academic achievement include: attendance to lectures, early revision, prioritization of learning needs, deep learning, learning in small groups, mind mapping, learning in skills lab, learning with patients, learning from mistakes, time management, and family support. Internal motivation and expected examination results are important drivers of high academic performance. Management of non-academic issues like sleep deprivation, homesickness, language barriers, and stress is also important for academic success. Addressing these factors, which might be unique for a given student community, in a systematic manner would be helpful to improve students' performance.

A high-sensitivity neutron counter and waste-drum counting with the high-sensitivity neutron instrument

International Nuclear Information System (INIS)

Hankins, D.E.; Thorngate, J.H.

1993-04-01

At Lawrence Livermore National Laboratory (LLNL), a highly sensitive neutron counter was developed that can detect and accurately measure the neutrons from small quantities of plutonium or from other low-level neutron sources. This neutron counter was originally designed to survey waste containers leaving the Plutonium Facility. However, it has proven to be useful in other research applications requiring a high-sensitivity neutron instrument

Highly sensitive magnetic field sensor based on microfiber coupler with magnetic fluid

International Nuclear Information System (INIS)

Luo, Longfeng; Pu, Shengli; Tang, Jiali; Zeng, Xianglong; Lahoubi, Mahieddine

2015-01-01

A kind of magnetic field sensor using a microfiber coupler (MFC) surrounded with magnetic fluid (MF) is proposed and experimentally demonstrated. As the MFC is strongly sensitive to the surrounding refractive index (RI) and MF's RI is sensitive to magnetic field, the magnetic field sensing function of the proposed structure is realized. Interrogation of magnetic field strength is achieved by measuring the dip wavelength shift and transmission loss change of the transmission spectrum. The experimental results show that the sensitivity of the sensor is wavelength-dependent. The maximum sensitivity of 191.8 pm/Oe is achieved at wavelength of around 1537 nm in this work. In addition, a sensitivity of −0.037 dB/Oe is achieved by monitoring variation of the fringe visibility. These suggest the potential applications of the proposed structure in tunable all-in-fiber photonic devices such as magneto-optical modulator, filter, and sensing

Highly sensitive magnetic field sensor based on microfiber coupler with magnetic fluid

Energy Technology Data Exchange (ETDEWEB)

Luo, Longfeng; Pu, Shengli, E-mail: shlpu@usst.edu.cn; Tang, Jiali [College of Science, University of Shanghai for Science and Technology, Shanghai 200093 (China); Zeng, Xianglong [2Key Laboratory of Specialty Fiber Optics and Optical Access Network, Shanghai University, Shanghai 200072 (China); Lahoubi, Mahieddine [Department of Physics, Faculty of Sciences, Laboratory L.P.S., Badji Mokhtar-Annaba University, P. O. Box 12, 23000 Annaba (Algeria)

2015-05-11

A kind of magnetic field sensor using a microfiber coupler (MFC) surrounded with magnetic fluid (MF) is proposed and experimentally demonstrated. As the MFC is strongly sensitive to the surrounding refractive index (RI) and MF's RI is sensitive to magnetic field, the magnetic field sensing function of the proposed structure is realized. Interrogation of magnetic field strength is achieved by measuring the dip wavelength shift and transmission loss change of the transmission spectrum. The experimental results show that the sensitivity of the sensor is wavelength-dependent. The maximum sensitivity of 191.8 pm/Oe is achieved at wavelength of around 1537 nm in this work. In addition, a sensitivity of −0.037 dB/Oe is achieved by monitoring variation of the fringe visibility. These suggest the potential applications of the proposed structure in tunable all-in-fiber photonic devices such as magneto-optical modulator, filter, and sensing.

Perspectives of High-Achieving Women on Teaching

Science.gov (United States)

Snodgrass, Helen

2010-01-01

High-achieving women are significantly less likely to enter the teaching profession than they were just 40 years ago. Why? While the social and economic reasons for this decline have been well documented in the literature, what is lacking is a discussion with high-achieving women, as they make their first career decisions, about their perceptions…

High-Sensitivity Spectrophotometry.

Science.gov (United States)

Harris, T. D.

1982-01-01

Selected high-sensitivity spectrophotometric methods are examined, and comparisons are made of their relative strengths and weaknesses and the circumstances for which each can best be applied. Methods include long path cells, noise reduction, laser intracavity absorption, thermocouple calorimetry, photoacoustic methods, and thermo-optical methods.…

High-speed asynchronous optical sampling for high-sensitivity detection of coherent phonons

International Nuclear Information System (INIS)

Dekorsy, T; Taubert, R; Hudert, F; Schrenk, G; Bartels, A; Cerna, R; Kotaidis, V; Plech, A; Koehler, K; Schmitz, J; Wagner, J

2007-01-01

A new optical pump-probe technique is implemented for the investigation of coherent acoustic phonon dynamics in the GHz to THz frequency range which is based on two asynchronously linked femtosecond lasers. Asynchronous optical sampling (ASOPS) provides the performance of on all-optical oscilloscope and allows us to record optically induced lattice dynamics over nanosecond times with femtosecond resolution at scan rates of 10 kHz without any moving part in the set-up. Within 1 minute of data acquisition time signal-to-noise ratios better than 10 7 are achieved. We present examples of the high-sensitivity detection of coherent phonons in superlattices and of the coherent acoustic vibration of metallic nanoparticles

High academic achievement in psychotic students.

Science.gov (United States)

Defries, Z; Grothe, L

1978-02-01

The authors studied 21 schizophrenic and borderline college students who achieved B+ or higher grade averages and underwent psychotherapy while in college. High academic achievement was found to provide relief from feelings of worthlessness and ineffectuality resulting from poor relationships with parents, siblings, and peers. Psychotherapy and the permissive yet supportive college atmosphere reinforced the students' self-esteem.

High sensitivity optical molecular imaging system

Science.gov (United States)

An, Yu; Yuan, Gao; Huang, Chao; Jiang, Shixin; Zhang, Peng; Wang, Kun; Tian, Jie

2018-02-01

Optical Molecular Imaging (OMI) has the advantages of high sensitivity, low cost and ease of use. By labeling the regions of interest with fluorescent or bioluminescence probes, OMI can noninvasively obtain the distribution of the probes in vivo, which play the key role in cancer research, pharmacokinetics and other biological studies. In preclinical and clinical application, the image depth, resolution and sensitivity are the key factors for researchers to use OMI. In this paper, we report a high sensitivity optical molecular imaging system developed by our group, which can improve the imaging depth in phantom to nearly 5cm, high resolution at 2cm depth, and high image sensitivity. To validate the performance of the system, special designed phantom experiments and weak light detection experiment were implemented. The results shows that cooperated with high performance electron-multiplying charge coupled device (EMCCD) camera, precision design of light path system and high efficient image techniques, our OMI system can simultaneously collect the light-emitted signals generated by fluorescence molecular imaging, bioluminescence imaging, Cherenkov luminance and other optical imaging modality, and observe the internal distribution of light-emitting agents fast and accurately.

Highly sensitive rotation sensing based on orthogonal fiber-optic structures

Science.gov (United States)

Yang, Yi; Wang, Zi-nan; Xu, Lian-yu; Wang, Cui-yun; Jia, Lei; Yu, Xiao-qi; Shao, Shan; Li, Zheng-bin

2011-08-01

In traditional fiber-optic gyroscopes (FOG), the polarization state of counter propagating waves is critically controlled, and only the mode polarized along one particular direction survives. This is important for a traditional single mode fiber gyroscope as the requirement of reciprocity. However, there are some fatal defects such as low accuracy and poor bias stability in traditional structures. In this paper, based on the idea of polarization multiplexing, a double-polarization structure is put forward and experimentally studied. In highly birefringent fibers or standard single mode fibers with induced anisotropy, two orthogonal polarization modes can be used at the same time. Therefore, in polarization maintaining fibers (PMF), each pair of counter propagating beams preserve reciprocity within their own polarization state. Two series of sensing results are gotten in the fast and slow axes in PMF. The two sensing results have their own systematic drifts and the correlation of random noise in them is approximately zero. So, beams in fast and slow axes work as two independent and orthogonal gyroscopes. In this way, amount of information is doubled, providing opportunity to eliminate noise and improve sensitivity. Theoretically, this double-polarization structure can achieve a sensitivity of 10-18 deg/h. Computer simulation demonstrates that random noise and systematic drifts are largely reduced in this novel structure. In experiment, a forty-hour stability test targeting the earth's rotation velocity is carried out. Experiment result shows that the orthogonal fiber-optic structure has two big advantages compared with traditional ones. Firstly, the structure gets true value without any bias correction in any axis and even time-varying bias does not affect the acquisition of true value. The unbiasedness makes the structure very attractive when sudden disturbances or temperature drifts existing in working environment. Secondly, the structure lowers bias for more than

High sensitivity optical fiber liquid level sensor based on a compact MMF-HCF-FBG structure

Science.gov (United States)

Zhang, Yunshan; Zhang, Weigang; Chen, Lei; Zhang, Yanxin; Wang, Song; Yan, Tieyi

2018-05-01

An ultra-high sensitivity fiber liquid level sensor based on wavelength demodulation is proposed and demonstrated. The sensor is composed of a segment of multimode fiber and a large aperture hollow-core fiber assisted by a fiber Bragg grating (FBG). Interference occurs due to core mismatching and different modes with different effective refractive indices. The experimental results show that the liquid level sensitivity of the sensor is 1.145 nm mm‑1, and the linearity is up to 0.996. The dynamic temperature compensation of the sensor can be achieved by cascading an FBG. Considering the high sensitivity and compact structure of the sensor, it can be used for real-time intelligent monitoring of tiny changes in liquid level.

Does Sensitivity to Criticism Mediate the Relationship between Theory of Mind and Academic Achievement?

Science.gov (United States)

Lecce, Serena; Caputi, Marcella; Hughes, Claire

2011-01-01

This study adds to the growing research on school outcomes associated with individual differences in preschoolers' theory of mind skills by considering whether "costs" of theory of mind (e.g., sensitivity to criticism) actually help to foster children's academic achievement. A group of 60 Italian children was tested during the last year…

Highly Sensitive and Very Stretchable Strain Sensor Based on a Rubbery Semiconductor.

Science.gov (United States)

Kim, Hae-Jin; Thukral, Anish; Yu, Cunjiang

2018-02-07

There is a growing interest in developing stretchable strain sensors to quantify the large mechanical deformation and strain associated with the activities for a wide range of species, such as humans, machines, and robots. Here, we report a novel stretchable strain sensor entirely in a rubber format by using a solution-processed rubbery semiconductor as the sensing material to achieve high sensitivity, large mechanical strain tolerance, and hysteresis-less and highly linear responses. Specifically, the rubbery semiconductor exploits π-π stacked poly(3-hexylthiophene-2,5-diyl) nanofibrils (P3HT-NFs) percolated in silicone elastomer of poly(dimethylsiloxane) to yield semiconducting nanocomposite with a large mechanical stretchability, although P3HT is a well-known nonstretchable semiconductor. The fabricated strain sensors exhibit reliable and reversible sensing capability, high gauge factor (gauge factor = 32), high linearity (R 2 > 0.996), and low hysteresis (degree of hysteresis wearable smart gloves. Systematic investigations in the materials design and synthesis, sensor fabrication and characterization, and mechanical analysis reveal the key fundamental and application aspects of the highly sensitive and very stretchable strain sensors entirely from rubbers.

A Novel High-Sensitivity, Low-Power, Liquid Crystal Temperature Sensor

Directory of Open Access Journals (Sweden)

José Francisco Algorri

2014-04-01

Full Text Available A novel temperature sensor based on nematic liquid crystal permittivity as a sensing magnitude, is presented. This sensor consists of a specific micrometric structure that gives considerable advantages from other previous related liquid crystal (LC sensors. The analytical study reveals that permittivity change with temperature is introduced in a hyperbolic cosine function, increasing the sensitivity term considerably. The experimental data has been obtained for ranges from −6 °C to 100 °C. Despite this, following the LC datasheet, theoretical ranges from −40 °C to 109 °C could be achieved. These results have revealed maximum sensitivities of 33 mVrms/°C for certain temperature ranges; three times more than of most silicon temperature sensors. As it was predicted by the analytical study, the micrometric size of the proposed structure produces a high output voltage. Moreover the voltage’s sensitivity to temperature response can be controlled by the applied voltage. This response allows temperature measurements to be carried out without any amplification or conditioning circuitry, with very low power consumption.

A Monolithic CMOS Magnetic Hall Sensor with High Sensitivity and Linearity Characteristics.

Science.gov (United States)

Huang, Haiyun; Wang, Dejun; Xu, Yue

2015-10-27

This paper presents a fully integrated linear Hall sensor by means of 0.8 μm high voltage complementary metal-oxide semiconductor (CMOS) technology. This monolithic Hall sensor chip features a highly sensitive horizontal switched Hall plate and an efficient signal conditioner using dynamic offset cancellation technique. An improved cross-like Hall plate achieves high magnetic sensitivity and low offset. A new spinning current modulator stabilizes the quiescent output voltage and improves the reliability of the signal conditioner. The tested results show that at the 5 V supply voltage, the maximum Hall output voltage of the monolithic Hall sensor microsystem, is up to ±2.1 V and the linearity of Hall output voltage is higher than 99% in the magnetic flux density range from ±5 mT to ±175 mT. The output equivalent residual offset is 0.48 mT and the static power consumption is 20 mW.

A Monolithic CMOS Magnetic Hall Sensor with High Sensitivity and Linearity Characteristics

Directory of Open Access Journals (Sweden)

Haiyun Huang

2015-10-01

Full Text Available This paper presents a fully integrated linear Hall sensor by means of 0.8 μm high voltage complementary metal-oxide semiconductor (CMOS technology. This monolithic Hall sensor chip features a highly sensitive horizontal switched Hall plate and an efficient signal conditioner using dynamic offset cancellation technique. An improved cross-like Hall plate achieves high magnetic sensitivity and low offset. A new spinning current modulator stabilizes the quiescent output voltage and improves the reliability of the signal conditioner. The tested results show that at the 5 V supply voltage, the maximum Hall output voltage of the monolithic Hall sensor microsystem, is up to ±2.1 V and the linearity of Hall output voltage is higher than 99% in the magnetic flux density range from ±5 mT to ±175 mT. The output equivalent residual offset is 0.48 mT and the static power consumption is 20 mW.

Attitudes and Opinions from the Nation's High Achieving Teens: 26th Annual Survey of High Achievers.

Science.gov (United States)

Who's Who among American High School Students, Lake Forest, IL.

A national survey of 3,351 high achieving high school students (junior and senior level) was conducted. All students had A or B averages. Topics covered include lifestyles, political beliefs, violence and entertainment, education, cheating, school violence, sexual violence and date rape, peer pressure, popularity, suicide, drugs and alcohol,…

Three-Dimensional Porous Nitrogen-Doped NiO Nanostructures as Highly Sensitive NO2 Sensors

Directory of Open Access Journals (Sweden)

Van Hoang Luan

2017-10-01

Full Text Available Nickel oxide has been widely used in chemical sensing applications, because it has an excellent p-type semiconducting property with high chemical stability. Here, we present a novel technique of fabricating three-dimensional porous nitrogen-doped nickel oxide nanosheets as a highly sensitive NO2 sensor. The elaborate nanostructure was prepared by a simple and effective hydrothermal synthesis method. Subsequently, nitrogen doping was achieved by thermal treatment with ammonia gas. When the p-type dopant, i.e., nitrogen atoms, was introduced in the three-dimensional nanostructures, the nickel-oxide-nanosheet-based sensor showed considerable NO2 sensing ability with two-fold higher responsivity and sensitivity compared to non-doped nickel-oxide-based sensors.

Student Perceptions of High-Achieving Classmates

Science.gov (United States)

Händel, Marion; Vialle, Wilma; Ziegler, Albert

2013-01-01

The reported study investigated students' perceptions of their high-performing classmates in terms of intelligence, social skills, and conscientiousness in different school subjects. The school subjects for study were examined with regard to cognitive, physical, and gender-specific issues. The results show that high academic achievements in…

Direct Printing of Stretchable Elastomers for Highly Sensitive Capillary Pressure Sensors.

Science.gov (United States)

Liu, Wenguang; Yan, Chaoyi

2018-03-28

We demonstrate the successful fabrication of highly sensitive capillary pressure sensors using an innovative 3D printing method. Unlike conventional capacitive pressure sensors where the capacitance changes were due to the pressure-induced interspace variations between the parallel plate electrodes, in our capillary sensors the capacitance was determined by the extrusion and extraction of liquid medium and consequent changes of dielectric constants. Significant pressure sensitivity advances up to 547.9 KPa -1 were achieved. Moreover, we suggest that our innovative capillary pressure sensors can adopt a wide range of liquid mediums, such as ethanol, deionized water, and their mixtures. The devices also showed stable performances upon repeated pressing cycles. The direct and versatile printing method combined with the significant performance advances are expected to find important applications in future stretchable and wearable electronics.

Highly enhanced photocurrent of novel quantum-dot-co-sensitized PbS-Hg/CdS/Cu:ZnO thin films for photoelectrochemical applications

International Nuclear Information System (INIS)

Gohel, Jignasa V.; Jana, A.K.; Singh, Mohit

2017-01-01

A novel quantum-dot-co-sensitized PbS-Hg/CdS/Cu:ZnO thin films synthesized by low-cost process. The properties of ZnO are also enhanced by doping and co-doping. It is also compared with quantum-dot co-sensitization. Optical properties, crystal structure, morphology, and photocurrent are characterized by UV-Vis spectroscopy, XRD, SEM, and solar simulator, respectively. The bandgap is interestingly reduced highly to 2.6 eV for Ag co-doped Cu:ZnO. It is unprecedentedly reduced to 2.1 eV and even 1.97 eV for CdS and PbS-Hg QD-sensitized thin films, respectively. An exceptionally enhanced photocurrent of 17.1 mA/cm"2 is achieved with PbS-Hg-co-sensitized CdS-sensitized Cu:ZnO thin film. This is an excellent achievement, which highly supports the potential of low-cost solar conversion. (orig.)

Highly enhanced photocurrent of novel quantum-dot-co-sensitized PbS-Hg/CdS/Cu:ZnO thin films for photoelectrochemical applications

Energy Technology Data Exchange (ETDEWEB)

Gohel, Jignasa V.; Jana, A.K.; Singh, Mohit [Sardar Vallabhbhai National Institute of Technology, Chemical Engineering Department, Surat, Gujarat (India)

2017-08-15

A novel quantum-dot-co-sensitized PbS-Hg/CdS/Cu:ZnO thin films synthesized by low-cost process. The properties of ZnO are also enhanced by doping and co-doping. It is also compared with quantum-dot co-sensitization. Optical properties, crystal structure, morphology, and photocurrent are characterized by UV-Vis spectroscopy, XRD, SEM, and solar simulator, respectively. The bandgap is interestingly reduced highly to 2.6 eV for Ag co-doped Cu:ZnO. It is unprecedentedly reduced to 2.1 eV and even 1.97 eV for CdS and PbS-Hg QD-sensitized thin films, respectively. An exceptionally enhanced photocurrent of 17.1 mA/cm{sup 2} is achieved with PbS-Hg-co-sensitized CdS-sensitized Cu:ZnO thin film. This is an excellent achievement, which highly supports the potential of low-cost solar conversion. (orig.)

Ultra-high sensitive hydrazine chemical sensor based on low-temperature grown ZnO nanoparticles

International Nuclear Information System (INIS)

Mehta, S.K.; Singh, Kulvinder; Umar, Ahmad; Chaudhary, G.R.; Singh, Sukhjinder

2012-01-01

Graphical abstract: Systematic representation of the fabricated amperometric hydrazine chemical sensor based on ZnO NPs/Au modified electrode. Highlights: ► Synthesis of well-crystalline ZnO NPs has been achieved in aqueous solution. ► ZnO NPs act as efficient electron mediators for hydrazine sensor. ► Extremely high sensitivity and low-detection limit have been obtained. - Abstract: Using well-crystalline ZnO nanoparticles (NPs), an ultra high sensitive hydrazine amperometric sensor has been fabricated and reported in this paper. The ZnO NPs have been synthesized by very simple aqueous solution process at 90 °C and characterized in detail in terms of their morphological, compositional, structural and optical properties. The detailed investigations reveal that the synthesized products are well-crystalline NPs, possessing wurtzite hexagonal phase and exhibit good optical properties. The fabricated amperometric hydrazine sensor exhibits ultra-high sensitivity of ∼97.133 μA cm −2 μM −1 and very low-detection limit of 147.54 nM. To the best of our knowledge, this is the first report in which an ultra-high sensitivity and low-detection limit have been obtained for the hydrazine chemical sensor based on ZnO nanostructures.

Single n+-i-n+ InP nanowires for highly sensitive terahertz detection.

Science.gov (United States)

Peng, Kun; Parkinson, Patrick; Gao, Qian; Boland, Jessica L; Li, Ziyuan; Wang, Fan; Mokkapati, Sudha; Fu, Lan; Johnston, Michael B; Tan, Hark Hoe; Jagadish, Chennupati

2017-03-24

Developing single-nanowire terahertz (THz) electronics and employing them as sub-wavelength components for highly-integrated THz time-domain spectroscopy (THz-TDS) applications is a promising approach to achieve future low-cost, highly integrable and high-resolution THz tools, which are desirable in many areas spanning from security, industry, environmental monitoring and medical diagnostics to fundamental science. In this work, we present the design and growth of n + -i-n + InP nanowires. The axial doping profile of the n + -i-n + InP nanowires has been calibrated and characterized using combined optical and electrical approaches to achieve nanowire devices with low contact resistances, on which the highly-sensitive InP single-nanowire photoconductive THz detectors have been demonstrated. While the n + -i-n + InP nanowire detector has a only pA-level response current, it has a 2.5 times improved signal-to-noise ratio compared with the undoped InP nanowire detector and is comparable to traditional bulk THz detectors. This performance indicates a promising path to nanowire-based THz electronics for future commercial applications.

Self-Concept and Achievement Motivation of High School Students

Science.gov (United States)

Lawrence, A. S. Arul; Vimala, A.

2013-01-01

The present study "Self-concept and Achievement Motivation of High School Students" was investigated to find the relationship between Self-concept and Achievement Motivation of High School Students. Data for the study were collected using Self-concept Questionnaire developed by Raj Kumar Saraswath (1984) and Achievement Motive Test (ACMT)…

Response to Marie Paz Morales' ``Influence of culture and language sensitive physics on science attitude achievement''

Science.gov (United States)

Cole, Mikel Walker

2015-12-01

This response to Marie Paz Morales' "Influence of culture and language sensitive physics on science attitude achievement" explores the ideas of culturally responsive pedagogy and critical literacy to examine some implications for culturally responsive science instruction implicit in the original manuscript.

Cross-National Estimates of the Effects of Family Background on Student Achievement: A Sensitivity Analysis

Science.gov (United States)

Nonoyama-Tarumi, Yuko

2008-01-01

This article uses the data from the Programme for International Student Assessment (PISA) 2000 to examine whether the influence of family background on educational achievement is sensitive to different measures of the family's socio-economic status (SES). The study finds that, when a multidimensional measure of SES is used, the family background has a stronger influence on achievement across countries than if the simpler measure of SES is used. The new measure, which incorporated aspects of parental occupation, education and cultural resources, was not biased towards more wealthy nations, Western nations, or urban population. However, when a proxy of wealth was included in the measure of SES, this reduced the other measured effects of family background on achievement in many countries.

Highly Sensitive Optical Receivers

CERN Document Server

Schneider, Kerstin

2006-01-01

Highly Sensitive Optical Receivers primarily treats the circuit design of optical receivers with external photodiodes. Continuous-mode and burst-mode receivers are compared. The monograph first summarizes the basics of III/V photodetectors, transistor and noise models, bit-error rate, sensitivity and analog circuit design, thus enabling readers to understand the circuits described in the main part of the book. In order to cover the topic comprehensively, detailed descriptions of receivers for optical data communication in general and, in particular, optical burst-mode receivers in deep-sub-µm CMOS are presented. Numerous detailed and elaborate illustrations facilitate better understanding.

Highly sensitive dendrimer-based nanoplasmonic biosensor for drug allergy diagnosis.

Science.gov (United States)

Soler, Maria; Mesa-Antunez, Pablo; Estevez, M-Carmen; Ruiz-Sanchez, Antonio Jesus; Otte, Marinus A; Sepulveda, Borja; Collado, Daniel; Mayorga, Cristobalina; Torres, Maria Jose; Perez-Inestrosa, Ezequiel; Lechuga, Laura M

2015-04-15

A label-free biosensing strategy for amoxicillin (AX) allergy diagnosis based on the combination of novel dendrimer-based conjugates and a recently developed nanoplasmonic sensor technology is reported. Gold nanodisks were functionalized with a custom-designed thiol-ending-polyamido-based dendron (d-BAPAD) peripherally decorated with amoxicilloyl (AXO) groups (d-BAPAD-AXO) in order to detect specific IgE generated in patient's serum against this antibiotic during an allergy outbreak. This innovative strategy, which follows a simple one-step immobilization procedure, shows exceptional results in terms of sensitivity and robustness, leading to a highly-reproducible and long-term stable surface which allows achieving extremely low limits of detection. Moreover, the viability of this biosensor approach to analyze human biological samples has been demonstrated by directly analyzing and quantifying specific anti-AX antibodies in patient's serum without any sample pretreatment. An excellent limit of detection (LoD) of 0.6ng/mL (i.e. 0.25kU/L) has been achieved in the evaluation of clinical samples evidencing the potential of our nanoplasmonic biosensor as an advanced diagnostic tool to quickly identify allergic patients. The results have been compared and validated with a conventional clinical immunofluorescence assay (ImmunoCAP test), confirming an excellent correlation between both techniques. The combination of a novel compact nanoplasmonic platform and a dendrimer-based strategy provides a highly sensitive label free biosensor approach with over two times better detectability than conventional SPR. Both the biosensor device and the carrier structure hold great potential in clinical diagnosis for biomarker analysis in whole serum samples and other human biological samples. Copyright © 2014 Elsevier B.V. All rights reserved.

One pot synthesis of multi-functional tin oxide nanostructures for high efficiency dye-sensitized solar cells

Energy Technology Data Exchange (ETDEWEB)

Wali, Qamar; Fakharuddin, Azhar; Yasin, Amina; Ab Rahim, Mohd Hasbi; Ismail, Jamil; Jose, Rajan, E-mail: rjose@ump.edu.my

2015-10-15

Photoanode plays a key role in dye sensitized solar cells (DSSCs) as a scaffold for dye molecules, transport medium for photogenerated electrons, and scatters light for improved absorption. Herein, tin oxide nanostructures unifying the above three characteristics were optimized by a hydrothermal process and used as photoanode in DSSCs. The optimized morphology is a combination of hollow porous nanoparticles of size ∼50 nm and micron sized spheres with BET surface area (up to 29 m{sup 2}/g) to allow large dye-loading and light scattering as well as high crystallinity to support efficient charge transport. The optimized morphology gave the highest photovoltaic conversion efficiency (∼7.5%), so far achieved in DSSCs with high open circuit voltage (∼700 mV) and short circuit current density (∼21 mA/cm{sup 2}) employing conventional N3 dye and iodide/triiodide electrolyte. The best performing device achieved an incident photon to current conversion efficiency of ∼90%. The performance of the optimized tin oxide nanostructures was comparable to that of conventional titanium based DSSCs fabricated at similar conditions. - Graphical abstract: Tin oxide hollow nanostructure simultaneously supporting improved light scattering, dye-loading, and charge transport yielded high photovoltaic conversion efficiency in dye-sensitized solar cells. - Highlights: • Uniformly and bimodelly distributed tin oxide hollow nanospheres (HNS) are synthesized. • Uniform HNS are of size ∼10 nm; bimodel HNS has additional size up to ∼800 nm. • They are evaluated as photoelectrodes in dye-sensitized solar cells (DSSCs). • The uniform HNS increase dye-loading and the larger increase light scattering in DSSCs. • Photo conversion efficiency ∼7.5% is achieved using bimodel HNS.

Response to Marie Paz Morales' "Influence of Culture and Language Sensitive Physics on Science Attitude Achievement"

Science.gov (United States)

Cole, Mikel Walker

2015-01-01

This response to Marie Paz Morales' "Influence of culture and language sensitive physics on science attitude achievement" explores the ideas of culturally responsive pedagogy and critical literacy to examine some implications for culturally responsive science instruction implicit in the original manuscript. [For "Influence of…

Catholic High Schools and Rural Academic Achievement.

Science.gov (United States)

Sander, William

1997-01-01

A study of national longitudinal data examined effects of rural Catholic high schools on mathematics achievement, high school graduation rates, and the likelihood that high school graduates attend college. Findings indicate that rural Catholic high schools had a positive effect on mathematics test scores and no effect on graduation rates or rates…

Development of an underwater high sensitivity Cherenkov detector: Sea Urchin

International Nuclear Information System (INIS)

Camerini, U.; McGibney, D.; Roberts, A.

1982-01-01

The need for a high gain, high sensitivity Cherenkov light sensor to be used in a deep underwater muon and neutrino detector (DUMAND) array has led to the design of the Sea Urchin detector. In this design a spherical photocathode PMTis optically coupled through a glass hemisphere to a large number of glass spines, each of which is filled with a wavelength-shifting (WLS) solution of a high quantum efficiency phosphor. The Cherenkov radiation is absorbed in the spine, isotropically re-radiated at a longer wavelength, and a fraction of the fluorescent light is internally reflected in the spine, and guided to the photomultiplier concentrically located in the glass hemisphere. Experiments measuring the optical characteristics of the spines and computer programs simulating light transformation and detection cross sections are described. Overall optical gains in the range 5-10 are achieved. The WLS solution is inexpensive, and may have other applications. (orig.)

Componential Analysis of Analogical-Reasoning Performance of High and Low Achievers.

Science.gov (United States)

Armour-Thomas, Eleanor; Allen, Brenda A.

1990-01-01

Assessed analogical reasoning in high- and low-achieving students at the high school level and determined whether analogical reasoning was related to academic achievement in ninth grade students (N=54). Results indicated that high achievers performed better than low achievers on all types of analogical-reasoning processes. (Author/ABL)

Sensitivity Enhancement of FBG-Based Strain Sensor.

Science.gov (United States)

Li, Ruiya; Chen, Yiyang; Tan, Yuegang; Zhou, Zude; Li, Tianliang; Mao, Jian

2018-05-17

A novel fiber Bragg grating (FBG)-based strain sensor with a high-sensitivity is presented in this paper. The proposed FBG-based strain sensor enhances sensitivity by pasting the FBG on a substrate with a lever structure. This typical mechanical configuration mechanically amplifies the strain of the FBG to enhance overall sensitivity. As this mechanical configuration has a high stiffness, the proposed sensor can achieve a high resonant frequency and a wide dynamic working range. The sensing principle is presented, and the corresponding theoretical model is derived and validated. Experimental results demonstrate that the developed FBG-based strain sensor achieves an enhanced strain sensitivity of 6.2 pm/με, which is consistent with the theoretical analysis result. The strain sensitivity of the developed sensor is 5.2 times of the strain sensitivity of a bare fiber Bragg grating strain sensor. The dynamic characteristics of this sensor are investigated through the finite element method (FEM) and experimental tests. The developed sensor exhibits an excellent strain-sensitivity-enhancing property in a wide frequency range. The proposed high-sensitivity FBG-based strain sensor can be used for small-amplitude micro-strain measurement in harsh industrial environments.

Academic attainment and the high school science experiences among high-achieving African American males

Science.gov (United States)

Trice, Rodney Nathaniel

This study examines the educational experiences of high achieving African American males. More specifically, it analyzes the influences on their successful navigation through high school science. Through a series of interviews, observations, questionnaires, science portfolios, and review of existing data the researcher attempted to obtain a deeper understanding of high achieving African American males and their limitations to academic attainment and high school science experiences. The investigation is limited to ten high achieving African American male science students at Woodcrest High School. Woodcrest is situated at the cross section of a suburban and rural community located in the southeastern section of the United States. Although this investigation involves African American males, all of whom are successful in school, its findings should not be generalized to this nor any other group of students. The research question that guided this study is: What are the limitations to academic attainment and the high school science experiences of high achieving African American males? The student participants expose how suspension and expulsion, special education placement, academic tracking, science instruction, and teacher expectation influence academic achievement. The role parents play, student self-concept, peer relationships, and student learning styles are also analyzed. The anthology of data rendered three overarching themes: (1) unequal access to education, (2) maintenance of unfair educational structures, and (3) authentic characterizations of African American males. Often the policies and practices set in place by school officials aid in creating hurdles to academic achievement. These policies and practices are often formed without meaningful consideration of the unintended consequences that may affect different student populations, particularly the most vulnerable. The findings from this study expose that high achieving African American males face major

Low and high achievers in math

DEFF Research Database (Denmark)

Overgaard, Steffen; Tonnesen, Pia Beck; Weng, Peter

2016-01-01

In this session we will present the results of the preliminary analysis of the qualitative and quantitative data, which can be used to enhance the teaching of low and high mathematics achievers so as to increase their mathematical knowledge and confidence....

Silver-coated Si nanograss as highly sensitive surface-enhanced Raman spectroscopy substrates

Energy Technology Data Exchange (ETDEWEB)

Tang, Jing; Kuo, Huei Pei; Hu, Min; Li, Zhiyong; Williams, R.S. [Hewlett-Packard Laboratories, Information and Quantum Systems Laboratory, Palo Alto, CA (United States); Ou, Fung Suong [Hewlett-Packard Laboratories, Information and Quantum Systems Laboratory, Palo Alto, CA (United States); Rice University, Department of Applied Physics, Houston, TX (United States); Stickle, William F. [Hewlett-Packard Company, Advanced Diagnostic Lab, Corvallis, OR (United States)

2009-09-15

We created novel surface-enhanced Raman spectroscopy (SERS) substrates by metalization (Ag) of Si nanograss prepared by a Bosch process which involves deep reactive ion etching of single crystalline silicon. No template or lithography was needed for making the Si nanograss, thus providing a simple and inexpensive method to achieve highly sensitive large-area SERS substrates. The dependence of the SERS effect on the thickness of the metal deposition and on the surface morphology and topology of the substrate prior to metal deposition was studied in order to optimize the SERS signals. We observed that the Ag-coated Si nanograss can achieve uniform SERS enhancement over large area ({proportional_to}1 cm x 1 cm) with an average EF (enhancement factor) of 4.2 x 10{sup 8} for 4-mercaptophenol probe molecules. (orig.)

Tuned cavity magnetometer sensitivity.

Energy Technology Data Exchange (ETDEWEB)

Okandan, Murat; Schwindt, Peter

2009-09-01

We have developed a high sensitivity (achieve similar sensitivity levels.

Development of a High-Sensitivity Wireless Accelerometer for Structural Health Monitoring.

Science.gov (United States)

Zhu, Li; Fu, Yuguang; Chow, Raymond; Spencer, Billie F; Park, Jong Woong; Mechitov, Kirill

2018-01-17

Structural health monitoring (SHM) is playing an increasingly important role in ensuring the safety of structures. A shift of SHM research away from traditional wired methods toward the use of wireless smart sensors (WSS) has been motivated by the attractive features of wireless smart sensor networks (WSSN). The progress achieved in Micro Electro-Mechanical System (MEMS) technologies and wireless data transmission, has extended the effectiveness and range of applicability of WSSNs. One of the most common sensors employed in SHM strategies is the accelerometer; however, most accelerometers in WSS nodes have inadequate resolution for measurement of the typical accelerations found in many SHM applications. In this study, a high-resolution and low-noise tri-axial digital MEMS accelerometer is incorporated in a next-generation WSS platform, the Xnode. In addition to meeting the acceleration sensing demands of large-scale civil infrastructure applications, this new WSS node provides powerful hardware and a robust software framework to enable edge computing that can deliver actionable information. Hardware and software integration challenges are presented, and the associate resolutions are discussed. The performance of the wireless accelerometer is demonstrated experimentally through comparison with high-sensitivity wired accelerometers. This new high-sensitivity wireless accelerometer will extend the use of WSSN to a broader class of SHM applications.

Development of a High-Sensitivity Wireless Accelerometer for Structural Health Monitoring

Science.gov (United States)

Zhu, Li; Fu, Yuguang; Chow, Raymond; Spencer, Billie F.; Park, Jong Woong; Mechitov, Kirill

2018-01-01

Structural health monitoring (SHM) is playing an increasingly important role in ensuring the safety of structures. A shift of SHM research away from traditional wired methods toward the use of wireless smart sensors (WSS) has been motivated by the attractive features of wireless smart sensor networks (WSSN). The progress achieved in Micro Electro-Mechanical System (MEMS) technologies and wireless data transmission, has extended the effectiveness and range of applicability of WSSNs. One of the most common sensors employed in SHM strategies is the accelerometer; however, most accelerometers in WSS nodes have inadequate resolution for measurement of the typical accelerations found in many SHM applications. In this study, a high-resolution and low-noise tri-axial digital MEMS accelerometer is incorporated in a next-generation WSS platform, the Xnode. In addition to meeting the acceleration sensing demands of large-scale civil infrastructure applications, this new WSS node provides powerful hardware and a robust software framework to enable edge computing that can deliver actionable information. Hardware and software integration challenges are presented, and the associate resolutions are discussed. The performance of the wireless accelerometer is demonstrated experimentally through comparison with high-sensitivity wired accelerometers. This new high-sensitivity wireless accelerometer will extend the use of WSSN to a broader class of SHM applications. PMID:29342102

Field test investigation of high sensitivity fiber optic seismic geophone

Science.gov (United States)

Wang, Meng; Min, Li; Zhang, Xiaolei; Zhang, Faxiang; Sun, Zhihui; Li, Shujuan; Wang, Chang; Zhao, Zhong; Hao, Guanghu

2017-10-01

Seismic reflection, whose measured signal is the artificial seismic waves ,is the most effective method and widely used in the geophysical prospecting. And this method can be used for exploration of oil, gas and coal. When a seismic wave travelling through the Earth encounters an interface between two materials with different acoustic impedances, some of the wave energy will reflect off the interface and some will refract through the interface. At its most basic, the seismic reflection technique consists of generating seismic waves and measuring the time taken for the waves to travel from the source, reflect off an interface and be detected by an array of geophones at the surface. Compared to traditional geophones such as electric, magnetic, mechanical and gas geophone, optical fiber geophones have many advantages. Optical fiber geophones can achieve sensing and signal transmission simultaneously. With the development of fiber grating sensor technology, fiber bragg grating (FBG) is being applied in seismic exploration and draws more and more attention to its advantage of anti-electromagnetic interference, high sensitivity and insensitivity to meteorological conditions. In this paper, we designed a high sensitivity geophone and tested its sensitivity, based on the theory of FBG sensing. The frequency response range is from 10 Hz to 100 Hz and the acceleration of the fiber optic seismic geophone is over 1000pm/g. sixteen-element fiber optic seismic geophone array system is presented and the field test is performed in Shengli oilfield of China. The field test shows that: (1) the fiber optic seismic geophone has a higher sensitivity than the traditional geophone between 1-100 Hz;(2) The low frequency reflection wave continuity of fiber Bragg grating geophone is better.

Highly Sensitive Bulk Silicon Chemical Sensors with Sub-5 nm Thin Charge Inversion Layers.

Science.gov (United States)

Fahad, Hossain M; Gupta, Niharika; Han, Rui; Desai, Sujay B; Javey, Ali

2018-03-27

There is an increasing demand for mass-producible, low-power gas sensors in a wide variety of industrial and consumer applications. Here, we report chemical-sensitive field-effect-transistors (CS-FETs) based on bulk silicon wafers, wherein an electrostatically confined sub-5 nm thin charge inversion layer is modulated by chemical exposure to achieve a high-sensitivity gas-sensing platform. Using hydrogen sensing as a "litmus" test, we demonstrate large sensor responses (>1000%) to 0.5% H 2 gas, with fast response (<60 s) and recovery times (<120 s) at room temperature and low power (<50 μW). On the basis of these performance metrics as well as standardized benchmarking, we show that bulk silicon CS-FETs offer similar or better sensing performance compared to emerging nanostructures semiconductors while providing a highly scalable and manufacturable platform.

Highly Sensitive Flexible Pressure Sensors Based on Printed Organic Transistors with Centro-Apically Self-Organized Organic Semiconductor Microstructures.

Science.gov (United States)

Yeo, So Young; Park, Sangsik; Yi, Yeon Jin; Kim, Do Hwan; Lim, Jung Ah

2017-12-13

A highly sensitive pressure sensor based on printed organic transistors with three-dimensionally self-organized organic semiconductor microstructures (3D OSCs) was demonstrated. A unique organic transistor with semiconductor channels positioned at the highest summit of printed cylindrical microstructures was achieved simply by printing an organic semiconductor and polymer blend on the plastic substrate without the use of additional etching or replication processes. A combination of the printed organic semiconductor microstructure and an elastomeric top-gate dielectric resulted in a highly sensitive organic field-effect transistor (FET) pressure sensor with a high pressure sensitivity of 1.07 kPa -1 and a rapid response time of <20 ms with a high reliability over 1000 cycles. The flexibility and high performance of the 3D OSC FET pressure sensor were exploited in the successful application of our sensors to real-time monitoring of the radial artery pulse, which is useful for healthcare monitoring, and to touch sensing in the e-skin of a realistic prosthetic hand.

Highly Sensitive Multifilament Fiber Strain Sensors with Ultrabroad Sensing Range for Textile Electronics.

Science.gov (United States)

Lee, Jaehong; Shin, Sera; Lee, Sanggeun; Song, Jaekang; Kang, Subin; Han, Heetak; Kim, SeulGee; Kim, Seunghoe; Seo, Jungmok; Kim, DaeEun; Lee, Taeyoon

2018-05-22

Highly stretchable fiber strain sensors are one of the most important components for various applications in wearable electronics, electronic textiles, and biomedical electronics. Herein, we present a facile approach for fabricating highly stretchable and sensitive fiber strain sensors by embedding Ag nanoparticles into a stretchable fiber with a multifilament structure. The multifilament structure and Ag-rich shells of the fiber strain sensor enable the sensor to simultaneously achieve both a high sensitivity and largely wide sensing range despite its simple fabrication process and components. The fiber strain sensor simultaneously exhibits ultrahigh gauge factors (∼9.3 × 10 5 and ∼659 in the first stretching and subsequent stretching, respectively), a very broad strain-sensing range (450 and 200% for the first and subsequent stretching, respectively), and high durability for more than 10 000 stretching cycles. The fiber strain sensors can also be readily integrated into a glove to control a hand robot and effectively applied to monitor the large volume expansion of a balloon and a pig bladder for an artificial bladder system, thereby demonstrating the potential of the fiber strain sensors as candidates for electronic textiles, wearable electronics, and biomedical engineering.

The Achievement of Therapeutic Objectives Scale: Interrater Reliability and Sensitivity to Change in Short-Term Dynamic Psychotherapy and Cognitive Therapy

Science.gov (United States)

Valen, Jakob; Ryum, Truls; Svartberg, Martin; Stiles, Tore C.; McCullough, Leigh

2011-01-01

This study examined interrater reliability and sensitivity to change of the Achievement of Therapeutic Objectives Scale (ATOS; McCullough, Larsen, et al., 2003) in short-term dynamic psychotherapy (STDP) and cognitive therapy (CT). The ATOS is a process scale originally developed to assess patients' achievements of treatment objectives in STDP,…

Flexible, highly sensitive pressure sensor with a wide range based on graphene-silk network structure

Science.gov (United States)

Liu, Ying; Tao, Lu-Qi; Wang, Dan-Yang; Zhang, Tian-Yu; Yang, Yi; Ren, Tian-Ling

2017-03-01

In this paper, a flexible, simple-preparation, and low-cost graphene-silk pressure sensor based on soft silk substrate through thermal reduction was demonstrated. Taking silk as the support body, the device had formed a three-dimensional structure with ordered multi-layer structure. Through a simple and low-cost process technology, graphene-silk pressure sensor can achieve the sensitivity value of 0.4 kPa - 1 , and the measurement range can be as high as 140 kPa. Besides, pressure sensor can have a good combination with knitted clothing and textile product. The signal had good reproducibility in response to different pressures. Furthermore, graphene-silk pressure sensor can not only detect pressure higher than 100 kPa, but also can measure weak body signals. The characteristics of high-sensitivity, good repeatability, flexibility, and comfort for skin provide the high possibility to fit on various wearable electronics.

A self-amplified transistor immunosensor under dual gate operation: highly sensitive detection of hepatitis B surface antigen

Science.gov (United States)

Lee, I.-K.; Jeun, M.; Jang, H.-J.; Cho, W.-J.; Lee, K. H.

2015-10-01

Ion-sensitive field-effect transistors (ISFETs), although they have attracted considerable attention as effective immunosensors, have still not been adopted for practical applications owing to several problems: (1) the poor sensitivity caused by the short Debye screening length in media with high ion concentration, (2) time-consuming preconditioning processes for achieving the highly-diluted media, and (3) the low durability caused by undesirable ions such as sodium chloride in the media. Here, we propose a highly sensitive immunosensor based on a self-amplified transistor under dual gate operation (immuno-DG ISFET) for the detection of hepatitis B surface antigen. To address the challenges in current ISFET-based immunosensors, we have enhanced the sensitivity of an immunosensor by precisely tailoring the nanostructure of the transistor. In the pH sensing test, the immuno-DG ISFET showed superior sensitivity (2085.53 mV per pH) to both standard ISFET under single gate operation (58.88 mV per pH) and DG ISFET with a non-tailored transistor (381.14 mV per pH). Moreover, concerning the detection of hepatitis B surface antigens (HBsAg) using the immuno-DG ISFET, we have successfully detected trace amounts of HBsAg (22.5 fg mL-1) in a non-diluted 1× PBS medium with a high sensitivity of 690 mV. Our results demonstrate that the proposed immuno-DG ISFET can be a biosensor platform for practical use in the diagnosis of various diseases.Ion-sensitive field-effect transistors (ISFETs), although they have attracted considerable attention as effective immunosensors, have still not been adopted for practical applications owing to several problems: (1) the poor sensitivity caused by the short Debye screening length in media with high ion concentration, (2) time-consuming preconditioning processes for achieving the highly-diluted media, and (3) the low durability caused by undesirable ions such as sodium chloride in the media. Here, we propose a highly sensitive immunosensor

High Sensitive pH Sensor Based on AlInN/GaN Heterostructure Transistor

Directory of Open Access Journals (Sweden)

Yan Dong

2018-04-01

Full Text Available The AlInN/GaN high-electron-mobility-transistor (HEMT indicates better performances compared with the traditional AlGaN/GaN HEMTs. The present work investigated the pH sensor functionality of an analogous HEMT AlInN/GaN device with an open gate. It was shown that the Al0.83In0.17N/GaN device demonstrates excellent pH sense functionality in aqueous solutions, exhibiting higher sensitivity (−30.83 μA/pH for AlInN/GaN and −4.6 μA/pH for AlGaN/GaN and a faster response time, lower degradation and good stability with respect to the AlGaN/GaN device, which is attributed to higher two-dimensional electron gas (2DEG density and a thinner barrier layer in Al0.83In0.17N/GaN owning to lattice matching. On the other hand, the open gate geometry was found to affect the pH sensitivity obviously. Properly increasing the width and shortening the length of the open gate area could enhance the sensitivity. However, when the open gate width is too larger or too small, the pH sensitivity would be suppressed conversely. Designing an optimal ratio of the width to the length is important for achieving high sensitivity. This work suggests that the AlInN/GaN-based 2DEG carrier modulated devices would be good candidates for high-performance pH sensors and other related applications.

High Sensitive pH Sensor Based on AlInN/GaN Heterostructure Transistor.

Science.gov (United States)

Dong, Yan; Son, Dong-Hyeok; Dai, Quan; Lee, Jun-Hyeok; Won, Chul-Ho; Kim, Jeong-Gil; Chen, Dunjun; Lee, Jung-Hee; Lu, Hai; Zhang, Rong; Zheng, Youdou

2018-04-24

The AlInN/GaN high-electron-mobility-transistor (HEMT) indicates better performances compared with the traditional AlGaN/GaN HEMTs. The present work investigated the pH sensor functionality of an analogous HEMT AlInN/GaN device with an open gate. It was shown that the Al 0.83 In 0.17 N/GaN device demonstrates excellent pH sense functionality in aqueous solutions, exhibiting higher sensitivity (−30.83 μA/pH for AlInN/GaN and −4.6 μA/pH for AlGaN/GaN) and a faster response time, lower degradation and good stability with respect to the AlGaN/GaN device, which is attributed to higher two-dimensional electron gas (2DEG) density and a thinner barrier layer in Al 0.83 In 0.17 N/GaN owning to lattice matching. On the other hand, the open gate geometry was found to affect the pH sensitivity obviously. Properly increasing the width and shortening the length of the open gate area could enhance the sensitivity. However, when the open gate width is too larger or too small, the pH sensitivity would be suppressed conversely. Designing an optimal ratio of the width to the length is important for achieving high sensitivity. This work suggests that the AlInN/GaN-based 2DEG carrier modulated devices would be good candidates for high-performance pH sensors and other related applications.

Methylation-Sensitive High Resolution Melting (MS-HRM).

Science.gov (United States)

Hussmann, Dianna; Hansen, Lise Lotte

2018-01-01

Methylation-Sensitive High Resolution Melting (MS-HRM) is an in-tube, PCR-based method to detect methylation levels at specific loci of interest. A unique primer design facilitates a high sensitivity of the assays enabling detection of down to 0.1-1% methylated alleles in an unmethylated background.Primers for MS-HRM assays are designed to be complementary to the methylated allele, and a specific annealing temperature enables these primers to anneal both to the methylated and the unmethylated alleles thereby increasing the sensitivity of the assays. Bisulfite treatment of the DNA prior to performing MS-HRM ensures a different base composition between methylated and unmethylated DNA, which is used to separate the resulting amplicons by high resolution melting.The high sensitivity of MS-HRM has proven useful for detecting cancer biomarkers in a noninvasive manner in urine from bladder cancer patients, in stool from colorectal cancer patients, and in buccal mucosa from breast cancer patients. MS-HRM is a fast method to diagnose imprinted diseases and to clinically validate results from whole-epigenome studies. The ability to detect few copies of methylated DNA makes MS-HRM a key player in the quest for establishing links between environmental exposure, epigenetic changes, and disease.

An application of impediography to the high sensitivity and high resolution identification of structural damage

International Nuclear Information System (INIS)

Zhao, L; Yang, J; Semperlotti, F; Wang, K W

2015-01-01

In this study we explore the use of impediographic techniques to perform damage detection in plate-like metal structures. Impediography relies on the piezo-resistive coupling of the host structure to reconstruct high sensitivity and high resolution maps of the internal electrical conductivity. By exploiting localized strain perturbations generated via focused acoustic waves, the piezo-resistive coupling allows extracting a set of linearly independent boundary voltage data that drastically reduces the ill-conditioning of the inverse problem, therefore increasing the performance. The localized perturbation is achieved by leveraging the concept of frequency selective structure (FSS), that is a dynamically tailored structural element enabling the required acoustic focusing via vibration localization. Based on the FSS approach, the impediographic technique is numerically tested to investigate the performance of the combined approach for structural damage detection. The effects of practical implementation issues, such as limited perturbations and limited boundary data, are also explored. (paper)

High sensitivity, high surface area Enzyme-linked Immunosorbent Assay (ELISA).

Science.gov (United States)

Singh, Harpal; Morita, Takahiro; Suzuki, Yuma; Shimojima, Masayuki; Le Van, An; Sugamata, Masami; Yang, Ming

2015-01-01

Enzyme-linked immunosorbent assays (ELISA) are considered the gold standard in the demonstration of various immunological reactions with an application in the detection of infectious diseases such as during outbreaks or in patient care. This study aimed to produce an ELISA-based diagnostic with an increased sensitivity of detection compared to the standard 96-well method in the immunologic diagnosis of infectious diseases. A '3DStack' was developed using readily available, low cost fabrication technologies namely nanoimprinting and press stamping with an increased surface area of 4 to 6 times more compared to 96-well plates. This was achieved by stacking multiple nanoimprinted polymer sheets. The flow of analytes between the sheets was enhanced by rotating the 3DStack and confirmed by Finite-Element (FE) simulation. An Immunoglobulin G (IgG) ELISA for the detection of antibodies in human serum raised against Rubella virus was performed for validation. An improved sensitivity of up to 1.9 folds higher was observed using the 3DStack compared to the standard method. The increased surface area of the 3DStack developed using nanoimprinting and press stamping technologies, and the flow pattern between sheets generated by rotating the 3DStack were potential contributors to a more sensitive ELISA-based diagnostic device.

Exploring High-Achieving Students' Images of Mathematicians

Science.gov (United States)

Aguilar, Mario Sánchez; Rosas, Alejandro; Zavaleta, Juan Gabriel Molina; Romo-Vázquez, Avenilde

2016-01-01

The aim of this study is to describe the images that a group of high-achieving Mexican students hold of mathematicians. For this investigation, we used a research method based on the Draw-A-Scientist Test (DAST) with a sample of 63 Mexican high school students. The group of students' pictorial and written descriptions of mathematicians assisted us…

High blood pressure and visual sensitivity

Science.gov (United States)

Eisner, Alvin; Samples, John R.

2003-09-01

The study had two main purposes: (1) to determine whether the foveal visual sensitivities of people treated for high blood pressure (vascular hypertension) differ from the sensitivities of people who have not been diagnosed with high blood pressure and (2) to understand how visual adaptation is related to standard measures of systemic cardiovascular function. Two groups of middle-aged subjects-hypertensive and normotensive-were examined with a series of test/background stimulus combinations. All subjects met rigorous inclusion criteria for excellent ocular health. Although the visual sensitivities of the two subject groups overlapped extensively, the age-related rate of sensitivity loss was, for some measures, greater for the hypertensive subjects, possibly because of adaptation differences between the two groups. Overall, the degree of steady-state sensitivity loss resulting from an increase of background illuminance (for 580-nm backgrounds) was slightly less for the hypertensive subjects. Among normotensive subjects, the ability of a bright (3.8-log-td), long-wavelength (640-nm) adapting background to selectively suppress the flicker response of long-wavelength-sensitive (LWS) cones was related inversely to the ratio of mean arterial blood pressure to heart rate. The degree of selective suppression was also related to heart rate alone, and there was evidence that short-term changes of cardiovascular response were important. The results suggest that (1) vascular hypertension, or possibly its treatment, subtly affects visual function even in the absence of eye disease and (2) changes in blood flow affect retinal light-adaptation processes involved in the selective suppression of the flicker response from LWS cones caused by bright, long-wavelength backgrounds.

A Simple Approach for Obtaining High Resolution, High Sensitivity ¹H NMR Metabolite Spectra of Biofluids with Limited Mass Supply

Energy Technology Data Exchange (ETDEWEB)

Hu, Jian Zhi; Rommereim, Donald N.; Wind, Robert A.; Minard, Kevin R.; Sears, Jesse A.

2006-11-01

A simple approach is reported that yields high resolution, high sensitivity ¹H NMR spectra of biofluids with limited mass supply. This is achieved by spinning a capillary sample tube containing a biofluid at the magic angle at a frequency of about 80Hz. A 2D pulse sequence called ¹H PASS is then used to produce a high-resolution ¹H NMR spectrum that is free from magnetic susceptibility induced line broadening. With this new approach a high resolution ¹H NMR spectrum of biofluids with a volume less than 1.0 µl can be easily achieved at a magnetic field strength as low as 7.05T. Furthermore, the methodology facilitates easy sample handling, i.e., the samples can be directly collected into inexpensive and disposable capillary tubes at the site of collection and subsequently used for NMR measurements. In addition, slow magic angle spinning improves magnetic field shimming and is especially suitable for high throughput investigations. In this paper first results are shown obtained in a magnetic field of 7.05T on urine samples collected from mice using a modified commercial NMR probe.

Early predictors of high school mathematics achievement.

Science.gov (United States)

Siegler, Robert S; Duncan, Greg J; Davis-Kean, Pamela E; Duckworth, Kathryn; Claessens, Amy; Engel, Mimi; Susperreguy, Maria Ines; Chen, Meichu

2012-07-01

Identifying the types of mathematics content knowledge that are most predictive of students' long-term learning is essential for improving both theories of mathematical development and mathematics education. To identify these types of knowledge, we examined long-term predictors of high school students' knowledge of algebra and overall mathematics achievement. Analyses of large, nationally representative, longitudinal data sets from the United States and the United Kingdom revealed that elementary school students' knowledge of fractions and of division uniquely predicts those students' knowledge of algebra and overall mathematics achievement in high school, 5 or 6 years later, even after statistically controlling for other types of mathematical knowledge, general intellectual ability, working memory, and family income and education. Implications of these findings for understanding and improving mathematics learning are discussed.

A High-Sensitivity Potentiometric 65-nm CMOS ISFET Sensor for Rapid E. coli Screening.

Science.gov (United States)

Jiang, Yu; Liu, Xu; Dang, Tran Chien; Huang, Xiwei; Feng, Hao; Zhang, Qing; Yu, Hao

2018-04-01

Foodborne bacteria, inducing outbreaks of infection or poisoning, have posed great threats to food safety. Potentiometric sensors can identify bacteria levels in food by measuring medium's pH changes. However, most of these sensors face the limitation of low sensitivity and high cost. In this paper, we developed a high-sensitivity ion-sensitive field-effect transistor sensor. It is small sized, cost-efficient, and can be massively fabricated in a standard 65-nm complementary metal-oxide-semiconductor process. A subthreshold pH-to-time-to-voltage conversion scheme was proposed to improve the sensitivity. Furthermore, design parameters, such as chemical sensing area, transistor size, and discharging time, were optimized to enhance the performance. The intrinsic sensitivity of passivation membrane was calculated as 33.2 mV/pH. It was amplified to 123.8 mV/pH with a 0.01-pH resolution, which greatly exceeded 6.3 mV/pH observed in a traditional source-follower based readout structure. The sensing system was applied to Escherichia coli (E. coli) detection with densities ranging from 14 to 140 cfu/mL. Compared to the conventional direct plate counting method (24 h), more efficient sixfold smaller screening time (4 h) was achieved to differentiate samples' E. coli levels. The demonstrated portable, time-saving, and low-cost prescreen system has great potential for food safety detection.

Achievement goals and perfectionism of high school students

Directory of Open Access Journals (Sweden)

Milojević Milica

2009-01-01

Full Text Available This research has been investigating one of the most contemporary approaches of achievement motivation - Achievement Goal Theory, which uses the construct of achievement goals. The construct of achievement goals involves three types of achievement goals: mastery goals, performance approach goals and performance avoidance goals. The main goal of the research was to examine correlation between perfectionism and its aspects with particular types of achievement goals. Also, the goal was to investigate the difference concerning gender regarding the achievement goals. The sample consisted of 200 senior year high school participants. The following instruments were used: Multi-dimensional scale of perfectionism (MSP and Test of achievement goals (TCP. The research results indicate that there is significant positive correlation between: perfectionism with performance approach goals and performance avoidance goals, concern over mistakes and parental expectations with performance approach goals and performance avoidance goals, personal standards and organization with mastery goals and performance approach goals, parental criticism and doubts about action with performance avoidance goals. Significant negative correlation was found between parental criticism and mastery goals. The results concerning the second goal indicates the female subjects have higher average scores in mastery goals.

High school achievement as a predictor for university performance

Directory of Open Access Journals (Sweden)

Meshkani Z

2004-07-01

Full Text Available Background: The high-school grade point average ( GPA-H and university entrance examination can predict the university achievement and Purpose. To examine the predictive value of GPA-H for GPA-U Methods: In this cross sectional study, the subjects were 240 medical students at basic science phase of their medical education. Data were collected by a questionnaire, consisting of questions measuring factual background variable and 10 Llikert-type questions measuring attitude. The multiple regression analysis was used. Results: The analysis showed that student GPA were a better predictor for educational achievement of medical students than rank on university entrance exam and students with high GPA have not been on probation at all. Also parent's education and occupation influence the students' attitudes toward their medical study. Conclusion: High-school GPA is a predictor for university GPA .This may warrant further investigation into criteria of medical university entrance exam. Keywords: UNIVERSITY ACHIEVEMENT, HIGH-SCHOOL GPA, UNIVERSITY SUCCESS, PREDICTOR

Design of a charge sensitive preamplifier on high resistivity silicon

International Nuclear Information System (INIS)

Radeka, V.; Rehak, P.; Rescia, S.; Gatti, E.; Longoni, A.; Sampietro, M.; Holl, P.; Strueder, L.; Kemmer, J.

1987-01-01

A low noise, fast charge sensitive preamplifier was designed on high resistivity, detector grade silicon. It is built at the surface of a fully depleted region of n-type silicon. This allows the preamplifier to be placed very close to a detector anode. The preamplifier uses the classical input cascode configuration with a capacitor and a high value resistor in the feedback loop. The output stage of the preamplifier can drive a load up to 20pF. The power dissipation of the preamplifier is 13mW. The amplifying elements are ''Single Sided Gate JFETs'' developed especially for this application. Preamplifiers connected to a low capacitance anode of a drift type detector should achieve a rise time of 20ns and have an equivalent noise charge (ENC), after a suitable shaping, of less than 50 electrons. This performance translates to a position resolution better than 3μm for silicon drift detectors. 6 refs., 9 figs

Chlorine-trapped CVD bilayer graphene for resistive pressure sensor with high detection limit and high sensitivity

Science.gov (United States)

Phuong Pham, Viet; Triet Nguyen, Minh; Park, Jin Woo; Kwak, Sung Soo; Nguyen, Dieu Hien Thi; Kyeom Mun, Mu; Danh Phan, Hoang; San Kim, Doo; Kim, Ki Hyun; Lee, Nae-Eung; Yeom, Geun Young

2017-06-01

Pressure sensing is one of the key functions for smart electronics. Considerably more effort is required to achieve the fabrication of pressure sensors that can imitate and overcome the sophisticated pressure sensing characteristics in nature and industry, especially in the innovation of materials and structures. Almost all of the pressure sensors reported until now have a high sensitivity at a low-pressure detection limit (type chlorine trap doping in the channel graphene with chlorine radicals without damaging the graphene. This work indicates that the ZGClG channel used for the pressure sensing device could also provide a simple and essential sensing platform for chemical-, medical-, and biological-sensing for future smart electronics.

Retinal sensitivity and choroidal thickness in high myopia.

Science.gov (United States)

Zaben, Ahmad; Zapata, Miguel Á; Garcia-Arumi, Jose

2015-03-01

To estimate the association between choroidal thickness in the macular area and retinal sensitivity in eyes with high myopia. This investigation was a transversal study of patients with high myopia, all of whom had their retinal sensitivity measured with macular integrity assessment microperimetry. The choroidal thicknesses in the macular area were then measured by optical coherence tomography, and statistical correlations between their functionality and the anatomical structuralism, as assessed by both types of measurements, were analyzed. Ninety-six eyes from 77 patients with high myopia were studied. The patients had a mean age ± standard deviation of 38.9 ± 13.2 years, with spherical equivalent values ranging from -6.00 diopter to -20.00 diopter (8.74 ± 2.73 diopter). The mean central choroidal thickness was 159.00 ± 50.57. The mean choroidal thickness was directly correlated with sensitivity (r = 0.306; P = 0.004) and visual acuity but indirectly correlated with the spherical equivalent values and patient age. The mean sensitivity was not significantly correlated with the macular foveal thickness (r = -0.174; P = 0.101) or with the overall macular thickness (r = 0.103; P = 0.334); furthermore, the mean sensitivity was significantly correlated with visual acuity (r = 0.431; P < 0.001) and the spherical equivalent values (r = -0.306; P = 0.003). Retinal sensitivity in highly myopic eyes is directly correlated with choroidal thickness and does not seem to be associated with retinal thickness. Thus, in patients with high myopia, accurate measurements of choroidal thickness may provide more accurate information about this pathologic condition because choroidal thickness correlates to a greater degree with the functional parameters, patient age, and spherical equivalent values.

Laser-engraved carbon nanotube paper for instilling high sensitivity, high stretchability, and high linearity in strain sensors

KAUST Repository

Xin, Yangyang

2017-06-29

There is an increasing demand for strain sensors with high sensitivity and high stretchability for new applications such as robotics or wearable electronics. However, for the available technologies, the sensitivity of the sensors varies widely. These sensors are also highly nonlinear, making reliable measurement challenging. Here we introduce a new family of sensors composed of a laser-engraved carbon nanotube paper embedded in an elastomer. A roll-to-roll pressing of these sensors activates a pre-defined fragmentation process, which results in a well-controlled, fragmented microstructure. Such sensors are reproducible and durable and can attain ultrahigh sensitivity and high stretchability (with a gauge factor of over 4.2 × 10(4) at 150% strain). Moreover, they can attain high linearity from 0% to 15% and from 22% to 150% strain. They are good candidates for stretchable electronic applications that require high sensitivity and linearity at large strains.

High sensitive radiation detector for radiology dosimetry

Energy Technology Data Exchange (ETDEWEB)

Valente, M.; Malano, F. [Instituto de Fisica Enrique Gaviola, Oficina 102 FaMAF - UNC, Av. Luis Medina Allende, Ciudad Universitaria, 5000 Cordoba (Argentina); Molina, W.; Vedelago, J., E-mail: valente@famac.unc.edu.ar [Laboratorio de Investigaciones e Instrumentacion en Fisica Aplicada a la Medicina e Imagenes por Rayos X, Laboratorio 448 FaMAF - UNC, Ciudad Universitaria, 5000 Cordoba (Argentina)

2014-08-15

Fricke solution has a wide range of applications as radiation detector and dosimetry. It is particularly appreciated in terms of relevant comparative advantages, like tissue equivalence when prepared in aqueous media like gel matrix, continuous mapping capability, dose rate recorded and incident direction independence as well as linear dose response. This work presents the development and characterization of a novel Fricke gel system, based on modified chemical compositions making possible its application in clinical radiology. Properties of standard Fricke gel dosimeter for high dose levels are used as starting point and suitable chemical modifications are introduced and carefully investigated in order to attain high resolution for low dose ranges, like those corresponding to radiology interventions. The developed Fricke gel radiation dosimeter system achieves the expected typical dose dependency, actually showing linear response in the dose range from 20 up to 4000 mGy. Systematic investigations including several chemical compositions are carried out in order to obtain a good enough dosimeter response for low dose levels. A suitable composition among those studied is selected as a good candidate for low dose level radiation dosimetry consisting on a modified Fricke solution fixed to a gel matrix containing benzoic acid along with sulfuric acid, ferrous sulfate, xylenol orange and ultra-pure reactive grade water. Dosimeter samples are prepared in standard vials for its in phantom irradiation and further characterization by spectrophotometry measuring visible light transmission and absorbance before and after irradiation. Samples are irradiated by typical kV X-ray tubes and calibrated Farmer type ionization chamber is used as reference to measure dose rates inside phantoms in at vials locations. Once sensitive material composition is already optimized, dose-response curves show significant improvement regarding overall sensitivity for low dose levels. According to

High sensitive radiation detector for radiology dosimetry

International Nuclear Information System (INIS)

Valente, M.; Malano, F.; Molina, W.; Vedelago, J.

2014-08-01

Fricke solution has a wide range of applications as radiation detector and dosimetry. It is particularly appreciated in terms of relevant comparative advantages, like tissue equivalence when prepared in aqueous media like gel matrix, continuous mapping capability, dose rate recorded and incident direction independence as well as linear dose response. This work presents the development and characterization of a novel Fricke gel system, based on modified chemical compositions making possible its application in clinical radiology. Properties of standard Fricke gel dosimeter for high dose levels are used as starting point and suitable chemical modifications are introduced and carefully investigated in order to attain high resolution for low dose ranges, like those corresponding to radiology interventions. The developed Fricke gel radiation dosimeter system achieves the expected typical dose dependency, actually showing linear response in the dose range from 20 up to 4000 mGy. Systematic investigations including several chemical compositions are carried out in order to obtain a good enough dosimeter response for low dose levels. A suitable composition among those studied is selected as a good candidate for low dose level radiation dosimetry consisting on a modified Fricke solution fixed to a gel matrix containing benzoic acid along with sulfuric acid, ferrous sulfate, xylenol orange and ultra-pure reactive grade water. Dosimeter samples are prepared in standard vials for its in phantom irradiation and further characterization by spectrophotometry measuring visible light transmission and absorbance before and after irradiation. Samples are irradiated by typical kV X-ray tubes and calibrated Farmer type ionization chamber is used as reference to measure dose rates inside phantoms in at vials locations. Once sensitive material composition is already optimized, dose-response curves show significant improvement regarding overall sensitivity for low dose levels. According to

Portable evanescent wave fiber biosensor for highly sensitive detection of Shigella

Science.gov (United States)

Xiao, Rui; Rong, Zhen; Long, Feng; Liu, Qiqi

2014-11-01

A portable evanescent wave fiber biosensor was developed to achieve the rapid and highly sensitive detection of Shigella. In this study, a DNA probe was covalently immobilized onto fiber-optic biosensors that can hybridize with a fluorescently labeled complementary DNA. The sensitivity of detection for synthesized oligonucleotides can reach 10-10 M. The surface of the sensor can be regenerated with 0.5% sodium dodecyl sulfate solution (pH 1.9) for over 30 times without significant deterioration of performance. The total analysis time for a single sample, including the time for measurement and surface regeneration, was less than 6 min. We employed real-time polymerase chain reaction (PCR) and compared the results of both methods to investigate the actual Shigella DNA detection capability of the fiber-optic biosensor. The fiber-optic biosensor could detect as low as 102 colony-forming unit/mL Shigella. This finding was comparable with that by real-time PCR, which suggests that this method is a potential alternative to existing detection methods.

High Achievement in Mathematics Education in India: A Report from Mumbai

Science.gov (United States)

Raman, Manya

2010-01-01

This paper reports a study aimed at characterizing the conditions that lead to high achievement in mathematics in India. The study involved eight schools in the greater Mumbai region. The main result of the study is that the notion of high achievement itself is problematic, as reflected in the reports about mathematics achievement within and…

High Involvement Mothers of High Achieving Children: Potential Theoretical Explanations

Science.gov (United States)

Hunsaker, Scott L.

2013-01-01

In American society, parents who have high aspirations for the achievements of their children are often viewed by others in a negative light. Various pejoratives such as "pushy parent," "helicopter parent," "stage mother," and "soccer mom" are used in the common vernacular to describe these parents. Multiple…

An Analysis of Java Programming Behaviors, Affect, Perceptions, and Syntax Errors among Low-Achieving, Average, and High-Achieving Novice Programmers

Science.gov (United States)

Rodrigo, Ma. Mercedes T.; Andallaza, Thor Collin S.; Castro, Francisco Enrique Vicente G.; Armenta, Marc Lester V.; Dy, Thomas T.; Jadud, Matthew C.

2013-01-01

In this article we quantitatively and qualitatively analyze a sample of novice programmer compilation log data, exploring whether (or how) low-achieving, average, and high-achieving students vary in their grasp of these introductory concepts. High-achieving students self-reported having the easiest time learning the introductory programming…

Achieving High Reliability with People, Processes, and Technology.

Science.gov (United States)

Saunders, Candice L; Brennan, John A

2017-01-01

High reliability as a corporate value in healthcare can be achieved by meeting the "Quadruple Aim" of improving population health, reducing per capita costs, enhancing the patient experience, and improving provider wellness. This drive starts with the board of trustees, CEO, and other senior leaders who ingrain high reliability throughout the organization. At WellStar Health System, the board developed an ambitious goal to become a top-decile health system in safety and quality metrics. To achieve this goal, WellStar has embarked on a journey toward high reliability and has committed to Lean management practices consistent with the Institute for Healthcare Improvement's definition of a high-reliability organization (HRO): one that is committed to the prevention of failure, early identification and mitigation of failure, and redesign of processes based on identifiable failures. In the end, a successful HRO can provide safe, effective, patient- and family-centered, timely, efficient, and equitable care through a convergence of people, processes, and technology.

A spirooxazine derivative as a highly sensitive cyanide sensor by means of UV-visible difference spectroscopy.

Science.gov (United States)

Zhu, Shaoyin; Li, Minjie; Sheng, Lan; Chen, Peng; Zhang, Yumo; Zhang, Sean Xiao-An

2012-12-07

A spirooxazine derivative 2-nitro-5a-(2-(4-dimethylaminophenyl)-ethylene)-6,6-dimethyl-5a,6-dihydro-12H-indolo[2,1-b][1,3]benzooxazine (P1) was explored as a sensitive cyanide probe. Different from conventional spiropyrans, P1 avoided locating the 3H-indolium cation and the 4-nitrophenolate anion in the same conjugated structure, which enhanced the positive charge of 3H-indolium cation so that the sensitivity and reaction speed were improved highly. UV-visible difference spectroscopy using P1 detection solution as a timely reference improved the measurement accuracy, prevented the error caused by the inherent absorption change of P1 solution with time. This enabled the "positive-negative alternative absorption peaks" in difference spectrum to be used as a finger-print to distinguish whether the spectral change was caused by cyanide. Benefiting from the special design of the molecular structure and the strategy of difference spectroscopy, P1 showed high selectivity and sensitivity for CN(-). A detection limit of 0.4 μM and a rate constant of 1.1 s(-1) were achieved.

Development of High Temperature/High Sensitivity Novel Chemical Resistive Sensor

Energy Technology Data Exchange (ETDEWEB)

Ma, Chunrui [Univ. of Texas, San Antonio, TX (United States); Enriquez, Erik [Univ. of Texas, San Antonio, TX (United States); Wang, Haibing [Univ. of Texas, San Antonio, TX (United States); Xu, Xing [Univ. of Texas, San Antonio, TX (United States); Bao, Shangyong [Univ. of Texas, San Antonio, TX (United States); Collins, Gregory [Univ. of Texas, San Antonio, TX (United States)

2013-08-13

The research has been focused to design, fabricate, and develop high temperature/high sensitivity novel multifunctional chemical sensors for the selective detection of fossil energy gases used in power and fuel systems. By systematically studying the physical properties of the LnBaCo₂O_5+d (LBCO) [Ln=Pr or La] thin-films, a new concept chemical sensor based high temperature chemical resistant change has been developed for the application for the next generation highly efficient and near zero emission power generation technologies. We also discovered that the superfast chemical dynamic behavior and an ultrafast surface exchange kinetics in the highly epitaxial LBCO thin films. Furthermore, our research indicates that hydrogen can superfast diffuse in the ordered oxygen vacancy structures in the highly epitaxial LBCO thin films, which suggest that the LBCO thin film not only can be an excellent candidate for the fabrication of high temperature ultra sensitive chemical sensors and control systems for power and fuel monitoring systems, but also can be an excellent candidate for the low temperature solid oxide fuel cell anode and cathode materials.

Perovskite Nanoparticle-Sensitized Ga2O3 Nanorod Arrays for CO Detection at High Temperature.

Science.gov (United States)

Lin, Hui-Jan; Baltrus, John P; Gao, Haiyong; Ding, Yong; Nam, Chang-Yong; Ohodnicki, Paul; Gao, Pu-Xian

2016-04-13

Noble metal nanoparticles are extensively used for sensitizing metal oxide chemical sensors through the catalytic spillover mechanism. However, due to earth-scarcity and high cost of noble metals, finding replacements presents a great economic benefit. Besides, high temperature and harsh environment sensor applications demand material stability under conditions approaching thermal and chemical stability limits of noble metals. In this study, we employed thermally stable perovskite-type La(0.8)Sr(0.2)FeO3 (LSFO) nanoparticle surface decoration on Ga2O3 nanorod array gas sensors and discovered an order of magnitude enhanced sensitivity to carbon monoxide at 500 °C. The LSFO nanoparticle catalysts was of comparable performance to that achieved by Pt nanoparticles, with a much lower weight loading than Pt. Detailed electron microscopy and X-ray photoelectron spectroscopy studies suggested the LSFO nanoparticle sensitization effect is attributed to a spillover-like effect associated with the gas-LSFO-Ga2O3 triple-interfaces that spread the negatively charged surface oxygen ions from LSFO nanoparticles surfaces over to β-Ga2O3 nanorod surfaces with faster surface CO oxidation reactions.

Position sensitive detection coupled to high-resolution time-of-flight mass spectrometry: Imaging for molecular beam deflection experiments

International Nuclear Information System (INIS)

Abd El Rahim, M.; Antoine, R.; Arnaud, L.; Barbaire, M.; Broyer, M.; Clavier, Ch.; Compagnon, I.; Dugourd, Ph.; Maurelli, J.; Rayane, D.

2004-01-01

We have developed and tested a high-resolution time-of-flight mass spectrometer coupled to a position sensitive detector for molecular beam deflection experiments. The major achievement of this new spectrometer is to provide a three-dimensional imaging (X and Y positions and time-of-flight) of the ion packet on the detector, with a high acquisition rate and a high resolution on both the mass and the position. The calibration of the experimental setup and its application to molecular beam deflection experiments are discussed

CRDS with a VECSEL for broad-band high sensitivity spectroscopy in the 2.3 μm window.

Science.gov (United States)

Čermák, P; Chomet, B; Ferrieres, L; Vasilchenko, S; Mondelain, D; Kassi, S; Campargue, A; Denet, S; Lecocq, V; Myara, M; Cerutti, L; Garnache, A

2016-08-01

The integration of an industry ready packaged Sb-based Vertical-External-Cavity Surface-Emitting-Laser (VECSEL) into a Cavity Ring Down Spectrometer (CRDS) is presented. The instrument operates in the important 2.3 μm atmospheric transparency window and provides a high sensitivity (minimum detectable absorption of 9 × 10(-11) cm(-1)) over a wide spectra range. The VECSEL performances combine a large continuous tunability over 120 cm(-1) around 4300 cm(-1) together with a powerful (∼5 mW) TEM00 diffraction limited beam and linewidth at MHz level (for 1 ms of integration time). The achieved performances are illustrated by high sensitivity recordings of the very weak absorption spectrum of water vapor in the region. The developed method gives potential access to the 2-2.7 μm range for CRDS.

Relationships Between Achievement Emotions, Motivation and Language Learning Strategies of High, Mid and Low English Language Achievers

Institute of Scientific and Technical Information of China (English)

TAN; Jun-ming

2017-01-01

Overseas research has shown that achievement emotions have direct relationships with ＂achievement outcome＂ and＂achievement activities＂. The purpose of the present study aimed to compare the relationships betweenachievement emotions, motivation, and language learning strategies of high, mid and low achievers in Englishlanguage learning at an international university in a southern province in China. Quantitative data were collectedthrough a questionnaire survey of 74 （16 males, 58 females） TESL major students. Results indicated that studentsin general experienced more positive than negative achievement emotions; more intrinsically rather thanextrinsically motivated to learn English; and quite frequently used a variety of learning strategies to overcome theirlearning difficulties. However, Year Four low-achievers experienced more negative achievement emotions. Theyseldom used metacognitive, affective and social learning strategies, and they had lower degrees of intrinsicmotivation. Implications for institutional support for at risk students are discussed.

Cones fabricated by 3D nanoimprint lithography for highly sensitive surface enhanced Raman spectroscopy

International Nuclear Information System (INIS)

Wu Wei; Hu Min; Ou Fungsuong; Li Zhiyong; Williams, R Stanley

2010-01-01

We demonstrated a cost-effective and deterministic method of patterning 3D cone arrays over a large area by using nanoimprint lithography (NIL). Cones with tip radius of less than 10 nm were successfully duplicated onto the UV-curable imprint resist materials from the silicon cone templates. Such cone structures were shown to be a versatile platform for developing reliable, highly sensitive surface enhanced Raman spectroscopy (SERS) substrates. In contrast to the silicon nanocones, the SERS substrates based on the Au coated cones made by the NIL offered significant improvement of the SERS signal. A further improvement of the SERS signal was observed when the polymer cones were imprinted onto a reflective metallic mirror surface. A sub-zeptomole detection sensitivity for a model molecule, trans-1,2-bis(4-pyridyl)-ethylene (BPE), on the Au coated NIL cone surfaces was achieved.

High-field modulated ion-selective field-effect-transistor (FET) sensors with sensitivity higher than the ideal Nernst sensitivity.

Science.gov (United States)

Chen, Yi-Ting; Sarangadharan, Indu; Sukesan, Revathi; Hseih, Ching-Yen; Lee, Geng-Yen; Chyi, Jen-Inn; Wang, Yu-Lin

2018-05-29

Lead ion selective membrane (Pb-ISM) coated AlGaN/GaN high electron mobility transistors (HEMT) was used to demonstrate a whole new methodology for ion-selective FET sensors, which can create ultra-high sensitivity (-36 mV/log [Pb 2+ ]) surpassing the limit of ideal sensitivity (-29.58 mV/log [Pb 2+ ]) in a typical Nernst equation for lead ion. The largely improved sensitivity has tremendously reduced the detection limit (10 -10  M) for several orders of magnitude of lead ion concentration compared to typical ion-selective electrode (ISE) (10 -7  M). The high sensitivity was obtained by creating a strong filed between the gate electrode and the HEMT channel. Systematical investigation was done by measuring different design of the sensor and gate bias, indicating ultra-high sensitivity and ultra-low detection limit obtained only in sufficiently strong field. Theoretical study in the sensitivity consistently agrees with the experimental finding and predicts the maximum and minimum sensitivity. The detection limit of our sensor is comparable to that of Inductively-Coupled-Plasma Mass Spectrum (ICP-MS), which also has detection limit near 10 -10  M.

Silicon nanowire structures as high-sensitive pH-sensors

International Nuclear Information System (INIS)

Belostotskaya, S O; Chuyko, O V; Kuznetsov, A E; Kuznetsov, E V; Rybachek, E N

2012-01-01

Sensitive elements for pH-sensors created on silicon nanostructures were researched. Silicon nanostructures have been used as ion-sensitive field effect transistor (ISFET) for the measurement of solution pH. Silicon nanostructures have been fabricated by 'top-down' approach and have been studied as pH sensitive elements. Nanowires have the higher sensitivity. It was shown, that sensitive element, which is made of 'one-dimensional' silicon nanostructure have bigger pH-sensitivity as compared with 'two-dimensional' structure. Integrated element formed from two p- and n-type nanowire ISFET ('inverter') can be used as high sensitivity sensor for local relative change [H+] concentration in very small volume.

High sensitive photonic crystal multiplexed biosensor array using H0 sandwiched cavities

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Arafa Safia

2017-01-01

Full Text Available We theoretically investigate a high sensitive photonic crystal integrated biosensor array structure which is potentially used for label-free multiplexed sensing. The proposed device consists of an array of three sandwiched H0 cavities patterned above silicon on insulator (SOI substrate; each cavity has been designed for different cavity spacing and different resonant wavelength. Results obtained by performing finite-difference time-domain (FDTD simulations, indicate that the response of each detection unit shifts independently in terms of refractive index variations. The optimized design makes possible the combination of sensing as a function of location, as well as a function of time in the same platform. A refractive index sensitivity of 520nm/RIU and a quality factor over 104 are both achieved with an accompanied crosstalk of less than -26 dB. In addition, the device presents an improved detection limit (DL of 1.24.10-6 RIU and a wide measurement range. These features make the designed device a promising element for performing label-free multiplexed detection in monolithic substrate for medical diagnostics and environmental monitoring.

Guided-Mode-Leaky-Mode-Guided-Mode Fiber Interferometer and Its High Sensitivity Refractive Index Sensing Technology

Directory of Open Access Journals (Sweden)

Qi Wang

2016-06-01

Full Text Available A cascaded symmetrical dual-taper Mach-Zehnder interferometer structure based on guided-mode and leaky-mode interference is proposed in this paper. Firstly, the interference spectrum characteristics of interferometer has been analyzed by the Finite Difference-Beam Propagation Method (FD-BPM. When the diameter of taper waist is 20 μm–30 μm, dual-taper length is 1 mm and taper distance is 4 cm–6 cm, the spectral contrast is higher, which is suitable for sensing. Secondly, experimental research on refractive index sensitivity is carried out. A refractive index sensitivity of 62.78 nm/RIU (refractive index unit can achieved in the RI range of 1.3333–1.3792 (0%~25% NaCl solution, when the sensor structure parameters meet the following conditions: diameter of taper waist is 24 μm, dual-taper length is 837 μm and taper distance is 5.5 cm. The spectrum contrast is 0.8 and measurement resolution is 1.6 × 10−5 RIU. The simulation analysis is highly consistent with experimental results. Research shows that the sensor has promising application in low RI fields where high-precision measurement is required due to its high sensitivity and stability.

Development of a highly sensitive lithium fluoride thermoluminescence dosimeter

International Nuclear Information System (INIS)

Moraes da Silva, Teresinha de; Campos, Leticia Lucente

1995-01-01

In recent times, LiF: Mg, Cu, P thermoluminescent phosphor has been increasingly in use for radiation monitoring due its high sensitivity and ease of preparation. The Dosimetric Materials Production Laboratory of IPEN, (Nuclear Energy Institute) has developed a simple method to obtain high sensitivity LiF. The preparation method is described. (author). 4 refs., 1 fig., 1 tab

Phase sensitive diffraction sensor for high sensitivity refractive index measurement

Science.gov (United States)

Kumawat, Nityanand; Varma, Manoj; Kumar, Sunil

2018-02-01

In this study a diffraction based sensor has been developed for bio molecular sensing applications and performing assays in real time. A diffraction grating fabricated on a glass substrate produced diffraction patterns both in transmission and reflection when illuminated by a laser diode. We used zeroth order I(0,0) as reference and first order I(0,1) as signal channel and conducted ratiometric measurements that reduced noise by more than 50 times. The ratiometric approach resulted in a very simple instrumentation with very high sensitivity. In the past, we have shown refractive index measurements both for bulk and surface adsorption using the diffractive self-referencing approach. In the current work we extend the same concept to higher diffraction orders. We have considered order I(0,1) and I(1,1) and performed ratiometric measurements I(0,1)/I(1,1) to eliminate the common mode fluctuations. Since orders I(0,1) and I(1,1) behaved opposite to each other, the resulting ratio signal amplitude increased more than twice compared to our previous results. As a proof of concept we used different salt concentrations in DI water. Increased signal amplitude and improved fluid injection system resulted in more than 4 times improvement in detection limit, giving limit of detection 1.3×10-7 refractive index unit (RIU) compared to our previous results. The improved refractive index sensitivity will help significantly for high sensitivity label free bio sensing application in a very cost-effective and simple experimental set-up.

Heterogeneous catalysis in highly sensitive microreactors

DEFF Research Database (Denmark)

Olsen, Jakob Lind

This thesis present a highly sensitive silicon microreactor and examples of its use in studying catalysis. The experimental setup built for gas handling and temperature control for the microreactor is described. The implementation of LabVIEW interfacing for all the experimental parts makes...

High-sensitivity β-Ga_2O_3 solar-blind photodetector on high-temperature pretreated c-plane sapphire substrate

KAUST Repository

Qian, Ling-Xuan

2017-09-20

Recently, monoclinic Ga2O3 (beta-Ga2O3) photodetectors (PDs) have been extensively studied for various commercial and military applications due to the merits of intrinsic solar rejection, high gain, and great compactness. In this work, c-plane sapphire substrates were annealed under different temperatures in a vacuum furnace prior to the molecular beam epitaxy (MBE) of beta-Ga2O3 thin film, which yielded a smoother surface and even a terraceand- step-like morphology on the substrate, resulting in improved crystallinity of the epitaxial film. Accordingly, both the dark and photo currents of beta-Ga2O3 metal-semiconductor-metal (MSM) PDs were increased by the enhanced carrier mobility (mu) of the more crystalline film. However, the substrate-annealing temperature must be sufficiently high to offset the rise of the dark current and thus achieve a remarkable improvement in the photodetection properties. As a result, the PD fabricated on the 1050 degrees C-annealed substrate exhibited extremely high sensitivity, for example, high responsivity (R) of 54.9 A/ W and large specific detectivity (D*) of 3.71 x 10(14) Jones. Both parameters were increased by one order of magnitude because of the combined effects of the dramatic increase in mu and the effective reduction in defect-related recombination centers. Nevertheless, the latter also prolonged the recovery time of the PD. These findings suggest another way to develop beta-Ga2O3 PD with extremely high sensitivity. (C) 2017 Optical Society of America

Sensitivity Achieved by the LIGO and Virgo Gravitational Wave Detectors during LIGO's Sixth and Virgo's Second and Third Science Runs

OpenAIRE

Abadie, J.; Abbott, B.; Abbott, R.; Abbott, T.; Abernathy, M.; Accadia, T.; Acernese, F.; Adams, C.; Adhikari, R.; Affeldt, C.; Agathos, M.; Ajith, P.; Allen, B.; Allen, G.; Amador Ceron, E.

2012-01-01

We summarize the sensitivity achieved by the LIGO and Virgo gravitational wave detectors for low-mass compact binary coalescence (CBC) searches during LIGO's sixth science run and Virgo's second and third science runs. We present strain noise power spectral densities (PSDs) which are representative of the typical performance achieved by the detectors in these science runs. The data presented here and in the accompanying web-accessible data files are intended to be released to the public as a ...

The selectively bred high alcohol sensitivity (HAS) and low alcohol sensitivity (LAS) rats differ in sensitivity to nicotine.

Science.gov (United States)

de Fiebre, NancyEllen C; Dawson, Ralph; de Fiebre, Christopher M

2002-06-01

Studies in rodents selectively bred to differ in alcohol sensitivity have suggested that nicotine and ethanol sensitivities may cosegregate during selective breeding. This suggests that ethanol and nicotine sensitivities may in part be genetically correlated. Male and female high alcohol sensitivity (HAS), control alcohol sensitivity, and low alcohol sensitivity (LAS) rats were tested for nicotine-induced alterations in locomotor activity, body temperature, and seizure activity. Plasma and brain levels of nicotine and its primary metabolite, cotinine, were measured in these animals, as was the binding of [3H]cytisine, [3H]epibatidine, and [125I]alpha-bungarotoxin in eight brain regions. Both replicate HAS lines were more sensitive to nicotine-induced locomotor activity depression than the replicate LAS lines. No consistent HAS/LAS differences were seen on other measures of nicotine sensitivity; however, females were more susceptible to nicotine-induced seizures than males. No HAS/LAS differences in nicotine or cotinine levels were seen, nor were differences seen in the binding of nicotinic ligands. Females had higher levels of plasma cotinine and brain nicotine than males but had lower brain cotinine levels than males. Sensitivity to a specific action of nicotine cosegregates during selective breeding for differential sensitivity to a specific action of ethanol. The differential sensitivity of the HAS/LAS rats is due to differences in central nervous system sensitivity and not to pharmacokinetic differences. The differential central nervous system sensitivity cannot be explained by differences in the numbers of nicotinic receptors labeled in ligand-binding experiments. The apparent genetic correlation between ethanol and nicotine sensitivities suggests that common genes modulate, in part, the actions of both ethanol and nicotine and may explain the frequent coabuse of these agents.

GIOVE: a new detector setup for high sensitivity germanium spectroscopy at shallow depth

International Nuclear Information System (INIS)

Heusser, G.; Weber, M.; Hakenmüller, J.; Laubenstein, M.; Lindner, M.; Maneschg, W.; Simgen, H.; Stolzenburg, D.; Strecker, H.

2015-01-01

We report on the development and construction of the high-purity germanium spectrometer setup GIOVE (Germanium Inner Outer VEto), recently built and now operated at the shallow underground laboratory of the Max-Planck-Institut für Kernphysik, Heidelberg. Particular attention was paid to the design of a novel passive and active shield, aiming at efficient rejection of environmental and muon induced radiation backgrounds. The achieved sensitivity level of ≤100 μBq kg -1 for primordial radionuclides from U and Th in typical γ ray sample screening measurements is unique among instruments located at comparably shallow depths and can compete with instruments at far deeper underground sites

GIOVE: a new detector setup for high sensitivity germanium spectroscopy at shallow depth

Energy Technology Data Exchange (ETDEWEB)

Heusser, G., E-mail: gerd.heusser@mpi-hd.mpg.de; Weber, M., E-mail: marc.weber@mpi-hd.mpg.de; Hakenmüller, J. [Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117, Heidelberg (Germany); Laubenstein, M. [Laboratori Nazionali del Gran Sasso, Via G. Acitelli 22, 67100, Assergi, AQ (Italy); Lindner, M.; Maneschg, W.; Simgen, H.; Stolzenburg, D.; Strecker, H. [Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117, Heidelberg (Germany)

2015-11-09

We report on the development and construction of the high-purity germanium spectrometer setup GIOVE (Germanium Inner Outer VEto), recently built and now operated at the shallow underground laboratory of the Max-Planck-Institut für Kernphysik, Heidelberg. Particular attention was paid to the design of a novel passive and active shield, aiming at efficient rejection of environmental and muon induced radiation backgrounds. The achieved sensitivity level of ≤100 μBq kg{sup -1} for primordial radionuclides from U and Th in typical γ ray sample screening measurements is unique among instruments located at comparably shallow depths and can compete with instruments at far deeper underground sites.

GIOVE: a new detector setup for high sensitivity germanium spectroscopy at shallow depth

Energy Technology Data Exchange (ETDEWEB)

Heusser, G.; Weber, M.; Hakenmueller, J.; Lindner, M.; Maneschg, W.; Simgen, H.; Stolzenburg, D.; Strecker, H. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Laubenstein, M. [Laboratori Nazionali del Gran Sasso, Assergi (Italy)

2015-11-15

We report on the development and construction of the high-purity germanium spectrometer setup GIOVE (Germanium Inner Outer VEto), recently built and now operated at the shallow underground laboratory of the Max-Planck-Institut fuer Kernphysik, Heidelberg. Particular attention was paid to the design of a novel passive and active shield, aiming at efficient rejection of environmental and muon induced radiation backgrounds. The achieved sensitivity level of ≤ 100μBq kg{sup -1} for primordial radionuclides from U and Th in typical γ ray sample screening measurements is unique among instruments located at comparably shallow depths and can compete with instruments at far deeper underground sites. (orig.)

Designing Metallic and Insulating Nanocrystal Heterostructures to Fabricate Highly Sensitive and Solution Processed Strain Gauges for Wearable Sensors.

Science.gov (United States)

Lee, Woo Seok; Lee, Seung-Wook; Joh, Hyungmok; Seong, Mingi; Kim, Haneun; Kang, Min Su; Cho, Ki-Hyun; Sung, Yun-Mo; Oh, Soong Ju

2017-12-01

All-solution processed, high-performance wearable strain sensors are demonstrated using heterostructure nanocrystal (NC) solids. By incorporating insulating artificial atoms of CdSe quantum dot NCs into metallic artificial atoms of Au NC thin film matrix, metal-insulator heterostructures are designed. This hybrid structure results in a shift close to the percolation threshold, modifying the charge transport mechanism and enhancing sensitivity in accordance with the site percolation theory. The number of electrical pathways is also manipulated by creating nanocracks to further increase its sensitivity, inspired from the bond percolation theory. The combination of the two strategies achieves gauge factor up to 5045, the highest sensitivity recorded among NC-based strain gauges. These strain sensors show high reliability, durability, frequency stability, and negligible hysteresis. The fundamental charge transport behavior of these NC solids is investigated and the combined site and bond percolation theory is developed to illuminate the origin of their enhanced sensitivity. Finally, all NC-based and solution-processed strain gauge sensor arrays are fabricated, which effectively measure the motion of each finger joint, the pulse of heart rate, and the movement of vocal cords of human. This work provides a pathway for designing low-cost and high-performance electronic skin or wearable devices. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The Role of Principal Leadership in Achievement beyond Test Scores: An Examination of Leadership, Differentiated Curriculum and High-Achieving Students

Science.gov (United States)

Else, Danielle F.

2013-01-01

Though research has validated a link between principal leadership and student achievement, questions remain regarding the specific relationship between the principal and high-achieving learners. This association facilitates understanding about forming curricular decisions for high ability learners. The study was conducted to examine the perceived…

A Study of Impulsivity in Low-Achieving and High-Achieving Boys from Lower Income Homes. Final Report.

Science.gov (United States)

Cohen, Shirley

The purpose of this study was to explore the concept of impulsivity as a stylistic dimension affecting cognitive behavior, and whether impulsivity operates as a comprehensive, inflexible orientation in low achievers more than in high achievers. The Matching Familiar Figures Test, the Porteus Maze Test, and the Stroop Color-Word Test were used to…

A high sensitivity nanomaterial based SAW humidity sensor

Energy Technology Data Exchange (ETDEWEB)

Wu, T-T; Chou, T-H [Institute of Applied Mechanics, National Taiwan University, Taipei 106, Taiwan (China); Chen, Y-Y [Department of Mechanical Engineering, Tatung University, Taipei 104, Taiwan (China)], E-mail: wutt@ndt.iam.ntu.edu.tw

2008-04-21

In this paper, a highly sensitive humidity sensor is reported. The humidity sensor is configured by a 128{sup 0}YX-LiNbO{sub 3} based surface acoustic wave (SAW) resonator whose operating frequency is at 145 MHz. A dual delay line configuration is realized to eliminate external temperature fluctuations. Moreover, for nanostructured materials possessing high surface-to-volume ratio, large penetration depth and fast charge diffusion rate, camphor sulfonic acid doped polyaniline (PANI) nanofibres are synthesized by the interfacial polymerization method and further deposited on the SAW resonator as selective coating to enhance sensitivity. The humidity sensor is used to measure various relative humidities in the range 5-90% at room temperature. Results show that the PANI nanofibre based SAW humidity sensor exhibits excellent sensitivity and short-term repeatability.

Academic achievement of junior high school students with sleep disorders

Directory of Open Access Journals (Sweden)

Fijri Auliyanti

2015-03-01

Full Text Available Background Sleep disorders are prevalent in adolescents and may influence their academic achievement. To date, no study has been done in Indonesia on academic achievement in students with sleep disorders and its related factors. Objective To assess for relationships between academic achievement and related factors, including gender, motivation and learning strategies, IQ level, maternal educational level, socioeconomic status, family structure, after-hours education program, presence of TV/computer in the bedroom, sleep duration during school days, as well as bedtime and wakeup time difference in junior high school students with sleep disorders. Methods This cross-sectional study was performed from January to March 2013. Subjects were students from five junior high schools in Jakarta who fulfilled the criteria for sleep disorders based on the Sleep Disturbance Scale for Children questionnaire. Results There were 111 study subjects. The prevalence of sleep disorders was 39.7%, mostly in difficulties initiating and maintaining sleep (70.2%. Below-average academic achievement was seen in 47.6% of subjects. Factors significantly related to below-average academic achievement were after-hours education program (prevalence ratio 5.6; 95%CI 1.36 to 23.18; P = 0.017, average IQ level (prevalence ratio 3.26; 95%CI 1.38 to 7.71; P = 0.007, and male gender (prevalence ratio 2.68; 95%CI 1.06 to 6.78; P = 0.037. Conclusion Among junior high school students with sleep disorders, factors related to below-average academic achievement are afterhours education program (more than 2 types, the average IQ level, and male gender.

High-Q Fabry–Pérot Micro-Cavities for High-Sensitivity Volume Refractometry

Directory of Open Access Journals (Sweden)

Noha Gaber

2018-01-01

Full Text Available This work reports a novel structure for a Fabry–Pérot micro cavity that combines the highest reported quality factor for an on-chip Fabry–Pérot resonator that exceeds 9800, and a very high sensitivity for an on-chip volume refractometer based on a Fabry–Pérot cavity that is about 1000 nm/refractive index unit (RIU. The structure consists of two cylindrical Bragg micromirrors that achieve confinement of the Gaussian beam in the plan parallel to the chip substrate, while for the perpendicular plan, external fiber rod lenses (FRLs are placed in the optical path of the input and the output of the cavity. This novel structure overcomes number of the drawbacks presented in previous designs. The analyte is passed between the mirrors, enabling its detection from the resonance peak wavelengths of the transmission spectra. Mixtures of ethanol and deionized (DI-water with different ratios are used as analytes with different refractive indices to exploit the device as a micro-opto-fluidic refractometer. The design criteria are detailed and the modeling is based on Gaussian-optics equations, which depicts a scenario closer to reality than the usually used ray-optics modeling.

A highly sensitive and selective aptamer-based colorimetric sensor for the rapid detection of PCB 77.

Science.gov (United States)

Cheng, Ruojie; Liu, Siyao; Shi, Huijie; Zhao, Guohua

2018-01-05

A highly sensitive, specific and simple colorimetric sensor based on aptamer was established for the detection of polychlorinated biphenyls (PCB 77). The use of unmodified gold nanoparticles as a colorimetric probe for aptamer sensors enabled the highly sensitive and selective detection of polychlorinated biphenyls (PCB 77). A linear range of 0.5nM to 900nM was obtained for the colorimetric assay with a minimum detection limit of 0.05nM. In addition, by the methods of circular dichroism, UV and naked eyes, we found that the 35 base fragments retained after cutting 5 bases from the 5 'end of aptamer plays the most significant role in the PCB 77 specific recognition process. We found a novel way to truncated nucleotides to optimize the detection of PCB 77, and the selected nucleotides also could achieve high affinity with PCB 77. At the same time, the efficient detection of the PCB 77 by our colorimetric sensor in the complex environmental water samples was realized, which shows a good application prospect. Copyright © 2017 Elsevier B.V. All rights reserved.

COMPARATIVE PERSPECTIVES OF STUDY STRATEGIES AMONG HIGH AND LOW ACHIEVERS DISTANCE LEARNING STUDENTS

Directory of Open Access Journals (Sweden)

Muhammad Imran YOUSUF

2009-07-01

Full Text Available The main aim of this research is to better understand and draw perceptions of low and high achiever distance learners about their study patterns. The study indicates the areas where significant difference is found among low and high achievers of Allama Iqbal Open University, Pakistan through a self developed questionnaire covering their preferred study location, study times, number of hours spent on study, the difficulties affecting their study patterns and the organization of study strategies in comparative perspective. Greater difficulties were being faced by low achievers in their study. Increased difficulties were encountered by low achievers with study material, volume of study, self-motivation and other factors. There was no significant difference between low and high achievers for their study strategies of studying materials without taking notes and reading aloud. Greater low achievers attempted easy portions of their study material first and took notes simultaneously as compared to high achievers.

Highly sensitive microcalorimeters for radiation research

International Nuclear Information System (INIS)

Avaev, V.N.; Demchuk, B.N.; Ioffe, L.A.; Efimov, E.P.

1984-01-01

Calorimetry is used in research at various types of nuclear-physics installations to obtain information on the quantitative and qualitative composition of ionizing radiation in a reactor core and in the surrounding layers of the biological shield. In this paper, the authors examine the characteristics of highly sensitive microcalorimeters with modular semiconductor heat pickups designed for operation in reactor channels. The microcalorimeters have a thin-walled aluminum housing on whose inner surface modular heat pickups are placed radially as shown here. The results of measurements of the temperature dependence of the sensitivity of the microcalorimeters are shown. The results of measuring the sensitivity of a PMK-2 microcalorimeter assembly as a function of integrated neutron flux for three energy intervals and the adsorbed gamma energy are shown. In order to study specimens with different shapes and sizes, microcalorimeters with chambers in the form of cylinders and a parallelepiped were built and tested

Experiences of families with a high-achiever child in sport: Case ...

African Journals Online (AJOL)

The family, not only the coach, plays a major role in the pursuit of children to reach the highest level in sport. Yet, it is mainly the high achiever, and sometimes the coach, who get recognition for success in this regard. This study explored the experiences of families with high-achieving adolescent athletes aspiring to compete ...

Highly sensitive multianalyte immunochromatographic test strip for rapid chemiluminescent detection of ractopamine and salbutamol

International Nuclear Information System (INIS)

Gao, Hongfei; Han, Jing; Yang, Shijia; Wang, Zhenxing; Wang, Lin; Fu, Zhifeng

2014-01-01

Graphical abstract: A multianalyte immunochromatographic test strip was developed for the rapid detection of two β 2 -agonists. Due to the application of chemiluminescent detection, this quantitative method shows much higher sensitivity. - Highlights: • An immunochromatographic test strip was developed for detection of multiple β 2 -agonists. • The whole assay process can be completed within 20 min. • The proposed method shows much higher sensitivity due to the application of CL detection. • It is a portable analytical tool suitable for field analysis and rapid screening. - Abstract: A novel immunochromatographic assay (ICA) was proposed for rapid and multiple assay of β 2 -agonists, by utilizing ractopamine (RAC) and salbutamol (SAL) as the models. Owing to the introduction of chemiluminescent (CL) approach, the proposed protocol shows much higher sensitivity. In this work, the described ICA was based on a competitive format, and horseradish peroxidase-tagged antibodies were used as highly sensitive CL probes. Quantitative analysis of β 2 -agonists was achieved by recording the CL signals of the probes captured on the two test zones of the nitrocellulose membrane. Under the optimum conditions, RAC and SAL could be detected within the linear ranges of 0.50–40 and 0.10–50 ng mL −1 , with the detection limits of 0.20 and 0.040 ng mL −1 (S/N = 3), respectively. The whole process for multianalyte immunoassay of RAC and SAL can be completed within 20 min. Furthermore, the test strip was validated with spiked swine urine samples and the results showed that this method was reliable in measuring β 2 -agonists in swine urine. This CL-based multianalyte test strip shows a series of advantages such as high sensitivity, ideal selectivity, simple manipulation, high assay efficiency and low cost. Thus, it opens up new pathway for rapid screening and field analysis, and shows a promising prospect in food safety

Highly sensitive multianalyte immunochromatographic test strip for rapid chemiluminescent detection of ractopamine and salbutamol

Energy Technology Data Exchange (ETDEWEB)

Gao, Hongfei; Han, Jing; Yang, Shijia; Wang, Zhenxing; Wang, Lin; Fu, Zhifeng, E-mail: fuzf@swu.edu.cn

2014-08-11

Graphical abstract: A multianalyte immunochromatographic test strip was developed for the rapid detection of two β{sub 2}-agonists. Due to the application of chemiluminescent detection, this quantitative method shows much higher sensitivity. - Highlights: • An immunochromatographic test strip was developed for detection of multiple β{sub 2}-agonists. • The whole assay process can be completed within 20 min. • The proposed method shows much higher sensitivity due to the application of CL detection. • It is a portable analytical tool suitable for field analysis and rapid screening. - Abstract: A novel immunochromatographic assay (ICA) was proposed for rapid and multiple assay of β{sub 2}-agonists, by utilizing ractopamine (RAC) and salbutamol (SAL) as the models. Owing to the introduction of chemiluminescent (CL) approach, the proposed protocol shows much higher sensitivity. In this work, the described ICA was based on a competitive format, and horseradish peroxidase-tagged antibodies were used as highly sensitive CL probes. Quantitative analysis of β{sub 2}-agonists was achieved by recording the CL signals of the probes captured on the two test zones of the nitrocellulose membrane. Under the optimum conditions, RAC and SAL could be detected within the linear ranges of 0.50–40 and 0.10–50 ng mL{sup −1}, with the detection limits of 0.20 and 0.040 ng mL{sup −1} (S/N = 3), respectively. The whole process for multianalyte immunoassay of RAC and SAL can be completed within 20 min. Furthermore, the test strip was validated with spiked swine urine samples and the results showed that this method was reliable in measuring β{sub 2}-agonists in swine urine. This CL-based multianalyte test strip shows a series of advantages such as high sensitivity, ideal selectivity, simple manipulation, high assay efficiency and low cost. Thus, it opens up new pathway for rapid screening and field analysis, and shows a promising prospect in food safety.

Parenting Style, Perfectionism, and Creativity in High-Ability and High-Achieving Young Adults

Science.gov (United States)

Miller, Angie L.; Lambert, Amber D.; Speirs Neumeister, Kristie L.

2012-01-01

The current study explores the potential relationships among perceived parenting style, perfectionism, and creativity in a high-ability and high-achieving young adult population. Using data from 323 honors college students at a Midwestern university, bivariate correlations suggested positive relationships between (a) permissive parenting style and…

A highly-sensitive label-free biosensor based on two dimensional photonic crystals with negative refraction

Science.gov (United States)

Malmir, Narges; Fasihi, Kiazand

2017-11-01

In this work, we present a novel high-sensitive optical label-free biosensor based on a two-dimensional photonic crystal (2D PC). The suggested structure is composed of a negative refraction structure in a hexagonal lattice PC, along with a positive refraction structure which is arranged in a square lattice PC. The frequency shift of the transmission peak is measured respect to the changes of refractive indices of the studied materials (the blood plasma, water, dry air and normal air). The studied materials are filled into a W1 line-defect waveguide which is located in the PC structure with positive refraction (the microfluidic nanochannel). Our numerical simulations, which are based on finite-difference time-domain (FDTD) method, show that in the proposed structure, a sensitivity about 1100 nm/RIU and a transmission efficiency more than 75% can be achieved. With this design, to the best of our knowledge, the obtained sensitivity and the transmission efficiency are one of the highest values in the reported PC label-free biosensors.

CRDS with a VECSEL for broad-band high sensitivity spectroscopy in the 2.3 μm window

Energy Technology Data Exchange (ETDEWEB)

Čermák, P., E-mail: cermak@fmph.uniba.sk [University Grenoble Alpes, LIPhy, F-38000 Grenoble (France); CNRS, LIPhy, UMR 5588, F-38000 Grenoble (France); Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University, Mlynská Dolina, 842 48 Bratislava (Slovakia); Chomet, B. [IES, CNRS, UMR5214, University Montpellier, F-34000 Montpellier (France); Innoptics, Institut d’Optique d’Aquitaine Rue François Mitterrand, 33400 Talence (France); Ferrieres, L.; Denet, S.; Lecocq, V. [Innoptics, Institut d’Optique d’Aquitaine Rue François Mitterrand, 33400 Talence (France); Vasilchenko, S. [University Grenoble Alpes, LIPhy, F-38000 Grenoble (France); CNRS, LIPhy, UMR 5588, F-38000 Grenoble (France); Laboratory of Molecular Spectroscopy, V.E. Zuev Institute of Atmospheric Optics, SB Russian Academy of Science, 1 Academician Zuev Square, 634021 Tomsk (Russian Federation); Mondelain, D.; Kassi, S.; Campargue, A. [University Grenoble Alpes, LIPhy, F-38000 Grenoble (France); CNRS, LIPhy, UMR 5588, F-38000 Grenoble (France); Myara, M.; Cerutti, L.; Garnache, A. [IES, CNRS, UMR5214, University Montpellier, F-34000 Montpellier (France)

2016-08-15

The integration of an industry ready packaged Sb-based Vertical-External-Cavity Surface-Emitting-Laser (VECSEL) into a Cavity Ring Down Spectrometer (CRDS) is presented. The instrument operates in the important 2.3 μm atmospheric transparency window and provides a high sensitivity (minimum detectable absorption of 9 × 10{sup −11} cm{sup −1}) over a wide spectra range. The VECSEL performances combine a large continuous tunability over 120 cm{sup −1} around 4300 cm{sup −1} together with a powerful (∼5 mW) TEM{sub 00} diffraction limited beam and linewidth at MHz level (for 1 ms of integration time). The achieved performances are illustrated by high sensitivity recordings of the very weak absorption spectrum of water vapor in the region. The developed method gives potential access to the 2-2.7 μm range for CRDS.

Student Perception of Academic Achievement Factors at High School

OpenAIRE

Bahar, Mustafa

2015-01-01

Measuring the quality of the ‘product’ is elemental in education, and most studies depend on observational data about student achievement factors, focusing overwhelmingly on quantitative data namely achievement scores, school data like attendance, facilities, expenditure class size etc. But there is little evidence of learner perceptions. 553 students from two different universities, who graduated from 3 high school types, were asked to respond to two fundamental questions to reflect on schoo...

Success Despite Socioeconomics: A Case Study of a High-Achieving, High-Poverty School

Science.gov (United States)

Tilley, Thomas Brent; Smith, Samuel J.; Claxton, Russell L.

2012-01-01

This case study of a high-achieving, high-poverty school describes the school's leadership, culture, and programs that contributed to its success. Data were collected from two surveys (the School Culture Survey and the Vanderbilt Assessment of Leadership in Education), observations at the school site, and interviews with school personnel. The…

Academic Self-Efficacy of High Achieving Students in Mexico

Science.gov (United States)

Camelo-Lavadores, Ana Karen; Sánchez-Escobedo, Pedro; Pinto-Sosa, Jesus

2017-01-01

The purpose of this study was to explore for differences in the academic self-efficacy of Mexican high school students. A gird questionnaire was administered to 1,460 students form private and public schools. As expected, high achieving students showed significantly higher academic self-efficacy that their peers. However, interesting gender…

Low Power and High Sensitivity MOSFET-Based Pressure Sensor

International Nuclear Information System (INIS)

Zhang Zhao-Hua; Ren Tian-Ling; Zhang Yan-Hong; Han Rui-Rui; Liu Li-Tian

2012-01-01

Based on the metal-oxide-semiconductor field effect transistor (MOSFET) stress sensitive phenomenon, a low power MOSFET pressure sensor is proposed. Compared with the traditional piezoresistive pressure sensor, the present pressure sensor displays high performances on sensitivity and power consumption. The sensitivity of the MOSFET sensor is raised by 87%, meanwhile the power consumption is decreased by 20%. (cross-disciplinary physics and related areas of science and technology)

Single photon detector with high polarization sensitivity.

Science.gov (United States)

Guo, Qi; Li, Hao; You, LiXing; Zhang, WeiJun; Zhang, Lu; Wang, Zhen; Xie, XiaoMing; Qi, Ming

2015-04-15

Polarization is one of the key parameters of light. Most optical detectors are intensity detectors that are insensitive to the polarization of light. A superconducting nanowire single photon detector (SNSPD) is naturally sensitive to polarization due to its nanowire structure. Previous studies focused on producing a polarization-insensitive SNSPD. In this study, by adjusting the width and pitch of the nanowire, we systematically investigate the preparation of an SNSPD with high polarization sensitivity. Subsequently, an SNSPD with a system detection efficiency of 12% and a polarization extinction ratio of 22 was successfully prepared.

Design Optimization and Fabrication of High-Sensitivity SOI Pressure Sensors with High Signal-to-Noise Ratios Based on Silicon Nanowire Piezoresistors

Directory of Open Access Journals (Sweden)

Jiahong Zhang

2016-10-01

Full Text Available In order to meet the requirement of high sensitivity and signal-to-noise ratios (SNR, this study develops and optimizes a piezoresistive pressure sensor by using double silicon nanowire (SiNW as the piezoresistive sensing element. First of all, ANSYS finite element method and voltage noise models are adopted to optimize the sensor size and the sensor output (such as sensitivity, voltage noise and SNR. As a result, the sensor of the released double SiNW has 1.2 times more sensitivity than that of single SiNW sensor, which is consistent with the experimental result. Our result also displays that both the sensitivity and SNR are closely related to the geometry parameters of SiNW and its doping concentration. To achieve high performance, a p-type implantation of 5 × 1018 cm−3 and geometry of 10 µm long SiNW piezoresistor of 1400 nm × 100 nm cross area and 6 µm thick diaphragm of 200 µm × 200 µm are required. Then, the proposed SiNW pressure sensor is fabricated by using the standard complementary metal-oxide-semiconductor (CMOS lithography process as well as wet-etch release process. This SiNW pressure sensor produces a change in the voltage output when the external pressure is applied. The involved experimental results show that the pressure sensor has a high sensitivity of 495 mV/V·MPa in the range of 0–100 kPa. Nevertheless, the performance of the pressure sensor is influenced by the temperature drift. Finally, for the sake of obtaining accurate and complete information over wide temperature and pressure ranges, the data fusion technique is proposed based on the back-propagation (BP neural network, which is improved by the particle swarm optimization (PSO algorithm. The particle swarm optimization–back-propagation (PSO–BP model is implemented in hardware using a 32-bit STMicroelectronics (STM32 microcontroller. The results of calibration and test experiments clearly prove that the PSO–BP neural network can be effectively applied

Achieving copper sulfide leaf like nanostructure electrode for high performance supercapacitor and quantum-dot sensitized solar cells

Science.gov (United States)

Durga, Ikkurthi Kanaka; Rao, S. Srinivasa; Reddy, Araveeti Eswar; Gopi, Chandu V. V. M.; Kim, Hee-Je

2018-03-01

Copper sulfide is an important multifunctional semiconductor that has attracted considerable attention owing to its outstanding properties and multiple applications, such as energy storage and electrochemical energy conversion. This paper describes a cost-effective and simple low-temperature solution approach to the preparation of copper sulfide for supercapacitors (SCs) and quantum-dot sensitized solar cells (QDSSCs). X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy confirmed that the nickel foam with a coriander leaf like nanostructure had been coated successfully with copper sulfide. As an electrode material for SCs, the CC-3 h showed excellent specific capacitance (5029.28 at 4 A g-1), energy density (169.73 W h kg-1), and superior cycling durability with 107% retention after 2000 cycles. Interestingly, the QDSSCs equipped with CC-2 h and CC-3 h counter electrodes (CEs) exhibited a maximum power conversion efficiency of 2.52% and 3.48%, respectively. The improved performance of the CC-3 h electrode was attributed mainly to the large surface area (which could contribute sufficient electroactive species), good conductivity, and high electrocatalytic activity. Overall, this work delivers novel insights into the use of copper sulfide and offers an important guidelines for the fabrication of next level energy storage and conversion devices.

International note: between-domain relations of Chinese high school students' academic achievements.

Science.gov (United States)

Yangyang, Liu

2012-08-01

The present study examined the between-domain relations of Chinese high school students' academic achievements. In a sample of 1870 Chinese 10th grade students, the results indicated that Chinese high school students' academic achievements were correlated across nine subjects. In line with the previous Western findings, the findings suggested that academic achievement was largely domain-general in nature. Copyright © 2012 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.

Performance of terahertz metamaterials as high-sensitivity sensor

Science.gov (United States)

He, Yanan; Zhang, Bo; Shen, Jingling

2017-09-01

A high-sensitivity sensor based on the resonant transmission characteristics of terahertz (THz) metamaterials was investigated, with the proposal and fabrication of rectangular bar arrays of THz metamaterials exhibiting a period of 180 μm on a 25 μm thick flexible polyimide. Varying the size of the metamaterial structure revealed that the length of the rectangular unit modulated the resonant frequency, which was verified by both experiment and simulation. The sensing characteristics upon varying the surrounding media in the sample were tested by simulation and experiment. Changing the surrounding medium from that of air to that of alcohol or oil produced resonant frequency redshifts of 80 GHz or 150 GHz, respectively, which indicates that the sensor possessed a high sensitivity of 667 GHz per unit of refractive index. Finally, the influence of the sample substrate thickness on the sensor sensitivity was investigated by simulation. It may be a reference for future sensor design.

Social class and academic achievement in college: the interplay of rejection sensitivity and entity beliefs.

Science.gov (United States)

Rheinschmidt, Michelle L; Mendoza-Denton, Rodolfo

2014-07-01

Undergraduates, especially those from lower income backgrounds, may perceive their social class background as different or disadvantaged relative to that of peers and worry about negative social treatment. We hypothesized that concerns about discrimination based on one's social class (i.e., class-based rejection sensitivity or RS-class) would be damaging to undergraduates' achievement outcomes particularly among entity theorists, who perceive their personal characteristics as fixed. We reasoned that a perceived capacity for personal growth and change, characteristic of incremental theorists, would make the pursuit of a college degree and upward mobility seem more worthwhile and attainable. We found evidence across 3 studies that dispositionally held and experimentally primed entity (vs. incremental) beliefs predicted college academic performance as a function of RS-class. Studies 1a and 1b documented that high levels of both entity beliefs and RS-class predicted lower self-reported and official grades, respectively, among undergraduates from socioeconomically diverse backgrounds. In Study 2, high entity beliefs and RS-class at matriculation predicted decreased year-end official grades among lower class Latino students. Study 3 established the causal relationship of entity (vs. incremental) beliefs on academic test performance as a function of RS-class. We observed worse test performance with higher RS-class levels following an entity (vs. incremental) prime, an effect driven by lower income students. Findings from a 4th study suggest that entity theorists with RS-class concerns tend to believe less in upward mobility and, following academic setbacks, are prone to personal attributions of failure, as well as hopelessness. Implications for education and intervention are discussed.

Is 2 Degrees Achievable? The Cold Turkey Experiment

Science.gov (United States)

Schwartz, S. E.

2017-12-01

The 2015 Paris Agreement calls for collective international action to hold the increase in global average temperature to well below 2˚C above preindustrial levels and to pursue efforts to limit the increase to 1.5°C. How much would carbon dioxide emissions have to be reduced to achieve these objectives, or can these objectives even be achieved at all? These questions are examined using a global energy balance model to carry out a "cold turkey" experiment in which emissions from fossil fuel combustion are abruptly halted; this is a limiting case for any practically achievable gradual reduction in emissions. The model study halts emissions not just of CO2 but also of atmospheric aerosols and precursor gases. These aerosols are thought to be offsetting a substantial but highly uncertain fraction of the radiative forcing of anthropogenic CO2 by scattering solar radiation and by increasing cloud reflectivity. In contrast to CO2, which would persist in the atmosphere for decades to centuries, aerosols would be removed almost immediately after cessation of emissions. Consequently, at least in the early decades following abrupt cessation of emissions, net forcing and global temperature would likely increase, not decrease. The magnitude of the temperature increase that would ensue depends on Earth's climate sensitivity and current aerosol forcing. These quantities are quite uncertain but are strongly correlated through observational constraints. Within present uncertainty it cannot be stated with confidence whether the 2˚C target could be achieved even if emissions were abruptly halted. Future global CO2 emissions consistent with achieving the 2˚C target range from as much as 100 years at current emission rates if Earth's climate sensitivity is at the low end of the range estimated by the IPCC 2013 Assessment Report, to zero, the committed temperature increase already exceeding the 2˚C limit, if sensitivity is at the high end of the IPCC range. Figure. Global mean

A High-Sensitivity Current Sensor Utilizing CrNi Wire and Microfiber Coils

Directory of Open Access Journals (Sweden)

Xiaodong Xie

2014-05-01

Full Text Available We obtain an extremely high current sensitivity by wrapping a section of microfiber on a thin-diameter chromium-nickel wire. Our detected current sensitivity is as high as 220.65 nm/A2 for a structure length of only 35 μm. Such sensitivity is two orders of magnitude higher than the counterparts reported in the literature. Analysis shows that a higher resistivity or/and a thinner diameter of the metal wire may produce higher sensitivity. The effects of varying the structure parameters on sensitivity are discussed. The presented structure has potential for low-current sensing or highly electrically-tunable filtering applications.

Integration of a highly ordered gold nanowires array with glucose oxidase for ultra-sensitive glucose detection.

Science.gov (United States)

Cui, Jiewu; Adeloju, Samuel B; Wu, Yucheng

2014-01-27

A highly sensitive amperometric nanobiosensor has been developed by integration of glucose oxidase (GO(x)) with a gold nanowires array (AuNWA) by cross-linking with a mixture of glutaraldehyde (GLA) and bovine serum albumin (BSA). An initial investigation of the morphology of the synthesized AuNWA by field emission scanning electron microscopy (FESEM) and field emission transmission electron microscopy (FETEM) revealed that the nanowires array was highly ordered with rough surface, and the electrochemical features of the AuNWA with/without modification were also investigated. The integrated AuNWA-BSA-GLA-GO(x) nanobiosensor with Nafion membrane gave a very high sensitivity of 298.2 μA cm(-2) mM(-1) for amperometric detection of glucose, while also achieving a low detection limit of 0.1 μM, and a wide linear range of 5-6000 μM. Furthermore, the nanobiosensor exhibited excellent anti-interference ability towards uric acid (UA) and ascorbic acid (AA) with the aid of Nafion membrane, and the results obtained for the analysis of human blood serum indicated that the device is capable of glucose detection in real samples. Copyright © 2013 Elsevier B.V. All rights reserved.

Nanowire-templated microelectrodes for high-sensitivity pH detection

DEFF Research Database (Denmark)

Antohe, V.A.; Radu, Adrian; Mátéfi-Tempfli, Mária

2009-01-01

A highly sensitive pH capacitive sensor has been designed by confined growth of vertically aligned nanowire arrays on interdigited microelectrodes. The active surface of the device has been functionalized with an electrochemical pH transducer (polyaniline). We easily tune the device features...... by combining lithographic techniques with electrochemical synthesis. The reported electrical LC resonance measurements show considerable sensitivity enhancement compared to conventional capacitive pH sensors realized with microfabricated interdigited electrodes. The sensitivity can be easily improved...

Site-specific growth of Au-Pd alloy horns on Au nanorods: A platform for highly sensitive monitoring of catalytic reactions by surface enhancement raman spectroscopy

KAUST Repository

Huang, Jianfeng; Zhu, Yihan; Lin, Ming; Wang, Qingxiao; Zhao, Lan; Yang, Yang; Yao, Kexin; Han, Yu

2013-01-01

Surface-enhanced Raman scattering (SERS) is a highly sensitive probe for molecular detection. The aim of this study was to develop an efficient platform for investigating the kinetics of catalytic reactions with SERS. To achieve this, we synthesized

Aluminum nanocantilevers for high sensitivity mass sensors

DEFF Research Database (Denmark)

Davis, Zachary James; Boisen, Anja

2005-01-01

We have fabricated Al nanocantilevers using a simple, one mask contact UV lithography technique with lateral and vertical dimensions under 500 and 100 nm, respectively. These devices are demonstrated as highly sensitive mass sensors by measuring their dynamic properties. Furthermore, it is shown ...

Relationship of Gender and Academic Achievement to Finnish Students' Intercultural Sensitivity

Science.gov (United States)

Holm, Kristiina; Nokelainen, Petri; Tirri, Kirsi

2009-01-01

This study examined the intercultural sensitivity of Finnish 12-16-year-old secondary school students (N=549) with a 23-item Intercultural Sensitivity Scale Questionnaire (ICSSQ). The ICSSQ is based on Bennett's (1993) Developmental Model of Intercultural Sensitivity (DMIS), which is a conceptual tool to situate certain reactions towards cultural…

Best Practices for Achieving High, Rapid Reading Gains

Science.gov (United States)

Carbo, Marie

2008-01-01

The percentage of students who read at the proficient level on the National Assessment of Educational Progress (NAEP) has not improved, and is appallingly low. In order for students to achieve high reading gains and become life-long readers, reading comprehension and reading enjoyment must be the top two goals. This article presents several…

The Pajarito Monitor: a high-sensitivity monitoring system for highly enriched uranium

International Nuclear Information System (INIS)

Fehlau, P.E.; Coop, K.; Garcia, C.; Martinez, J.

1984-01-01

The Pajarito Monitor for Special Nuclear Material is a high-sensitivity gamma-ray monitoring system for detecting small quantities of highly enriched uranium transported by pedestrians or motor vehicles. The monitor consists of two components: a walk-through personnel monitor and a vehicle monitor. The personnel monitor has a plastic-scintillator detector portal, a microwave occupancy monitor, and a microprocessor control unit that measures the radiation intensity during background and monitoring periods to detect transient diversion signals. The vehicle monitor examines stationary motor vehicles while the vehicle's occupants pass through the personnel portal to exchange their badges. The vehicle monitor has four groups of large plastic scintillators that scan the vehicle from above and below. Its microprocessor control unit measures separate radiation intensities in each detector group. Vehicle occupancy is sensed by a highway traffic detection system. Each monitor's controller is responsible for detecting diversion as well as serving as a calibration and trouble-shooting aid. Diversion signals are detected by a sequential probability ratio hypothesis test that minimizes the monitoring time in the vehicle monitor and adapts itself well to variations in individual passage speed in the personnel monitor. Designed to be highly sensitive to diverted enriched uranium, the monitoring system also exhibits exceptional sensitivity for plutonium

An Underwater Acoustic Vector Sensor with High Sensitivity and Broad Band

Directory of Open Access Journals (Sweden)

Hu Zhang

2014-05-01

Full Text Available Recently, acoustic vector sensor that use accelerators as sensing elements are widely used in underwater acoustic engineering, but the sensitivity of which at low frequency band is usually lower than -220 dB. In this paper, using a piezoelectric trilaminar optimized low frequency sensing element, we designed a high sensitivity internal placed ICP piezoelectric accelerometer as sensing element. Through structure optimization, we made a high sensitivity, broadband, small scale vector sensor. The working band is 10-2000 Hz, sound pressure sensitivity is -185 dB (at 100 Hz, outer diameter is 42 mm, length is 80 mm.

Multi-service highly sensitive rectifier for enhanced RF energy scavenging.

Science.gov (United States)

Shariati, Negin; Rowe, Wayne S T; Scott, James R; Ghorbani, Kamran

2015-05-07

Due to the growing implications of energy costs and carbon footprints, the need to adopt inexpensive, green energy harvesting strategies are of paramount importance for the long-term conservation of the environment and the global economy. To address this, the feasibility of harvesting low power density ambient RF energy simultaneously from multiple sources is examined. A high efficiency multi-resonant rectifier is proposed, which operates at two frequency bands (478-496 and 852-869 MHz) and exhibits favorable impedance matching over a broad input power range (-40 to -10 dBm). Simulation and experimental results of input reflection coefficient and rectified output power are in excellent agreement, demonstrating the usefulness of this innovative low-power rectification technique. Measurement results indicate an effective efficiency of 54.3%, and an output DC voltage of 772.8 mV is achieved for a multi-tone input power of -10 dBm. Furthermore, the measured output DC power from harvesting RF energy from multiple services concurrently exhibits a 3.14 and 7.24 fold increase over single frequency rectification at 490 and 860 MHz respectively. Therefore, the proposed multi-service highly sensitive rectifier is a promising technique for providing a sustainable energy source for low power applications in urban environments.

The Impact of Inclusive STEM High Schools on Student Achievement

Directory of Open Access Journals (Sweden)

Jennifer Gnagey

2016-05-01

Full Text Available This study is one of the first to estimate the impact of “inclusive“ science, technology, engineering, and mathematics (STEM high schools using student-level data. We use multiple statistical strategies to estimate the effect on student achievement from 2 years of attendance at six such high schools in Ohio. The results indicate that two schools had positive effects on science achievement that appear to come at the expense of achievement in social studies. The other schools had negligible or, often, negative effects across both STEM and, particularly, non-STEM subjects. These results are consistent with studies indicating that inclusive STEM schools typically focus on problem-based, personalized learning rather than science and mathematics content. The analysis also reveals the importance of accounting for students’ prior test scores in science, in addition to math and reading, when estimating models that use only 1 year of prior test score data—something that existing studies fail to do.

Achieving high fusion reactivity in high poloidal beta discharges in TFTR

International Nuclear Information System (INIS)

Manuel, M.E.; Navratil, G.A.; Sabbagh, S.A.; Batha, S.; Bell, M.G.; Bell, R.; Budny, R.V.; Bush, C.E.; Cavallo, A.; Chance, M.S.; Cheng, C.Z.; Efthimion, P.C.; Fredrickson, E.D.; Fu, G.Y.; Hawryluk, R.J.; Janos, A.C.; Jassby, D.L.; Levinton, F.; Mikkelsen, D.R.; Manickam, J.; McCune, D.C.; McGuire, K.M.; Medley, S.S.; Mueller, D.; Nagayama, Y.; Owens, D.K.; Park, H.K.; Ramsey, A.T.; Stratton, B.C.; Synakowski, E.J.; Taylor, G.; Wieland, R.M.; Yamada, M.; Zarnstorff, M.C.: Zweben, S.; Kesner, J.; Marmar, E.; Snipes, J.; Terry, J.

1993-04-01

High poloidal beta discharges have been produced in TFTR that achieved high fusion reactivities at low plasma currents. By rapidly decreasing the plasma current just prior to high-power neutral beam injection, relatively peaked current profiles were created having high l i > 2, high Troyon-normalized beta, βN > 3, and high poloidal beta. β p ≥ 0.7 R/a. The global energy confinement time after the current ramp was comparable to supershots, and the combination of improved MHD stability and good confinement produced a new high εβ p high Q DD operating mode for TFTR. Without steady-state current profile control, as the pulse lengths of high βp discharges were extended, l i decreased, and the improved stability produced immediately after by the current ramp deteriorated. In four second, high εβ p discharges, the current profile broadened under the influence of bootstrap and beam-drive currents. When the calculated voltage throughout the plasma nearly vanished, MHD instabilities were observed with β N as low as 1.4. Ideal MHD stability calculations showed this lower beta limit to be consistent with theoretical expectations

2×2 dominant achievement goal profiles in high-level swimmers.

Science.gov (United States)

Fernandez-Rio, Javier; Cecchini Estrada, Jose A; Mendez-Giménez, Antonio; Fernández-Garcia, Benjamín; Saavedra, Pablo

2014-01-01

The goal of this study was to assess achievement goal dominance, self-determined situational motivation and competence in high-level swimmers before and after three training sessions set at different working intensities (medium, sub-maximal and maximal). Nineteen athletes (males, n=9, 18.00±2.32 years; females, n=10, 16.30±2.01 years, range = 14-18) agreed to participate. They completed a questionnaire that included the Dominant Achievement Goal assessment instrument, the 2×2 Achievement Goals Questionnaire for Sport (AGQ-S), The Situational Motivation Scale (SIMS) and the Competence subscale of the Basic Psychological Needs in Exercise questionnaire (BPNES). Results indicated that participants overwhelmingly showed mastery-approach achievement goal dominance, and it remained stable at the conclusion of the different training sessions under all intensity levels. This profile was positively correlated to self-determined situational motivation and competence. However, swimmers' feelings of competence increased only after the medium intensity level training session. After the completion of the maximal intensity training session, swimmers' self-determined motivation was significantly lower compared to the other two training sessions, which could be caused by a temporary period of burnout. Results indicated that high-level swimmers had a distinct mastery-approach dominant achievement goal profile that was not affected by the workload of the different training sessions. They also showed high levels of self-determined situational motivation and competence. However, heavy workloads should be controlled because they can cause transitory burnout.

Ultra-sensitive high performance liquid chromatography-laser-induced fluorescence based proteomics for clinical applications.

Science.gov (United States)

Patil, Ajeetkumar; Bhat, Sujatha; Pai, Keerthilatha M; Rai, Lavanya; Kartha, V B; Chidangil, Santhosh

2015-09-08

An ultra-sensitive high performance liquid chromatography-laser induced fluorescence (HPLC-LIF) based technique has been developed by our group at Manipal, for screening, early detection, and staging for various cancers, using protein profiling of clinical samples like, body fluids, cellular specimens, and biopsy-tissue. More than 300 protein profiles of different clinical samples (serum, saliva, cellular samples and tissue homogenates) from volunteers (normal, and different pre-malignant/malignant conditions) were recorded using this set-up. The protein profiles were analyzed using principal component analysis (PCA) to achieve objective detection and classification of malignant, premalignant and healthy conditions with high sensitivity and specificity. The HPLC-LIF protein profiling combined with PCA, as a routine method for screening, diagnosis, and staging of cervical cancer and oral cancer, is discussed in this paper. In recent years, proteomics techniques have advanced tremendously in life sciences and medical sciences for the detection and identification of proteins in body fluids, tissue homogenates and cellular samples to understand biochemical mechanisms leading to different diseases. Some of the methods include techniques like high performance liquid chromatography, 2D-gel electrophoresis, MALDI-TOF-MS, SELDI-TOF-MS, CE-MS and LC-MS techniques. We have developed an ultra-sensitive high performance liquid chromatography-laser induced fluorescence (HPLC-LIF) based technique, for screening, early detection, and staging for various cancers, using protein profiling of clinical samples like, body fluids, cellular specimens, and biopsy-tissue. More than 300 protein profiles of different clinical samples (serum, saliva, cellular samples and tissue homogenates) from healthy and volunteers with different malignant conditions were recorded by using this set-up. The protein profile data were analyzed using principal component analysis (PCA) for objective

No-core fiber-based highly sensitive optical fiber pH sensor.

Science.gov (United States)

Bhardwaj, Vanita; Pathak, Akhilesh Kumar; Singh, Vinod Kumar

2017-05-01

The present work describes the fabrication and characterization of an optical fiber pH sensor using a sol–gel technique. The sensing head configuration is incorporated using a short section of no-core fiber, coated with tetraethyl orthosilicate and spliced at the end of a single mode fiber with a bulge. Different types of indicators (bromophenol blue, cresol red, and chlorophenol red) were used to achieve a wide pH range from 2 to 13. High sensitivities of the fabricated device were found to be 1.02 and ? 0.93 ?? nm / pH for acidic and alkaline solutions, respectively. From the characterization results, it was noted that there is an impact of ionic strength and an effect of the temperature of liquid on the response characteristic, which is an advantage of the existing device over the other pH sensors. The fabricated sensor exhibited good reflection spectrum, indicating a blueshift in resonance wavelength for alkaline solutions and a redshift for acidic solutions.

High-resolution, high-sensitivity NMR of nano-litre anisotropic samples by coil spinning

Energy Technology Data Exchange (ETDEWEB)

Sakellariou, D [CEA Saclay, DSM, DRECAM, SCM, Lab Struct and Dynam Resonance Magnet, CNRS URA 331, F-91191 Gif Sur Yvette, (France); Le Goff, G; Jacquinot, J F [CEA Saclay, DSM, DRECAM, SPEC: Serv Phys Etat Condense, CNRS URA 2464, F-91191 Gif Sur Yvette, (France)

2007-07-01

Nuclear magnetic resonance (NMR) can probe the local structure and dynamic properties of liquids and solids, making it one of the most powerful and versatile analytical methods available today. However, its intrinsically low sensitivity precludes NMR analysis of very small samples - as frequently used when studying isotopically labelled biological molecules or advanced materials, or as preferred when conducting high-throughput screening of biological samples or 'lab-on-a-chip' studies. The sensitivity of NMR has been improved by using static micro-coils, alternative detection schemes and pre-polarization approaches. But these strategies cannot be easily used in NMR experiments involving the fast sample spinning essential for obtaining well-resolved spectra from non-liquid samples. Here we demonstrate that inductive coupling allows wireless transmission of radio-frequency pulses and the reception of NMR signals under fast spinning of both detector coil and sample. This enables NMR measurements characterized by an optimal filling factor, very high radio-frequency field amplitudes and enhanced sensitivity that increases with decreasing sample volume. Signals obtained for nano-litre-sized samples of organic powders and biological tissue increase by almost one order of magnitude (or, equivalently, are acquired two orders of magnitude faster), compared to standard NMR measurements. Our approach also offers optimal sensitivity when studying samples that need to be confined inside multiple safety barriers, such as radioactive materials. In principle, the co-rotation of a micrometer-sized detector coil with the sample and the use of inductive coupling (techniques that are at the heart of our method) should enable highly sensitive NMR measurements on any mass-limited sample that requires fast mechanical rotation to obtain well-resolved spectra. The method is easy to implement on a commercial NMR set-up and exhibits improved performance with miniaturization, and we

Multimode fiber tip Fabry-Perot cavity for highly sensitive pressure measurement.

Science.gov (United States)

Chen, W P; Wang, D N; Xu, Ben; Zhao, C L; Chen, H F

2017-03-23

We demonstrate an optical Fabry-Perot interferometer fiber tip sensor based on an etched end of multimode fiber filled with ultraviolet adhesive. The fiber device is miniature (with diameter of less than 60 μm), robust and low cost, in a convenient reflection mode of operation, and has a very high gas pressure sensitivity of -40.94 nm/MPa, a large temperature sensitivity of 213 pm/°C within the range from 55 to 85 °C, and a relatively low temperature cross-sensitivity of 5.2 kPa/°C. This device has a high potential in monitoring environment of high pressure.

When high achievers and low achievers work in the same group: the roles of group heterogeneity and processes in project-based learning.

Science.gov (United States)

Cheng, Rebecca Wing-yi; Lam, Shui-fong; Chan, Joanne Chung-yan

2008-06-01

There has been an ongoing debate about the inconsistent effects of heterogeneous ability grouping on students in small group work such as project-based learning. The present research investigated the roles of group heterogeneity and processes in project-based learning. At the student level, we examined the interaction effect between students' within-group achievement and group processes on their self- and collective efficacy. At the group level, we examined how group heterogeneity was associated with the average self- and collective efficacy reported by the groups. The participants were 1,921 Hong Kong secondary students in 367 project-based learning groups. Student achievement was determined by school examination marks. Group processes, self-efficacy and collective efficacy were measured by a student-report questionnaire. Hierarchical linear modelling was used to analyse the nested data. When individual students in each group were taken as the unit of analysis, results indicated an interaction effect of group processes and students' within-group achievement on the discrepancy between collective- and self-efficacy. When compared with low achievers, high achievers reported lower collective efficacy than self-efficacy when group processes were of low quality. However, both low and high achievers reported higher collective efficacy than self-efficacy when group processes were of high quality. With 367 groups taken as the unit of analysis, the results showed that group heterogeneity, group gender composition and group size were not related to the discrepancy between collective- and self-efficacy reported by the students. Group heterogeneity was not a determinant factor in students' learning efficacy. Instead, the quality of group processes played a pivotal role because both high and low achievers were able to benefit when group processes were of high quality.

High mass resolution time of flight mass spectrometer for measuring products in heterogeneous catalysis in highly sensitive microreactors

DEFF Research Database (Denmark)

Andersen, Thomas; Jensen, Robert; Christensen, M. K.

2012-01-01

We demonstrate a combined microreactor and time of flight system for testing and characterization of heterogeneous catalysts with high resolution mass spectrometry and high sensitivity. Catalyst testing is performed in silicon-based microreactors which have high sensitivity and fast thermal...

Sensitive parameters' optimization of the permanent magnet supporting mechanism

Energy Technology Data Exchange (ETDEWEB)

Liu, Yongguang; Gao, Xiaohui; Wang, Yixuan; Yang, Xiaowei [Beihang University, Beijing (China)

2014-07-15

The fast development of the ultra-high speed vertical rotor promotes the study and exploration for the supporting mechanism. It has become the focus of research that how to improve the speed and overcome the vibration when the rotors pass through the low-order critical frequencies. This paper introduces a kind of permanent magnet (PM) supporting mechanism and describes an optimization method of its sensitive parameters, which can make the vertical rotor system reach 80000 r/min smoothly. Firstly we find the sensitive parameters through analyzing the rotor's features in the process of achieving high-speed, then, study these sensitive parameters and summarize the regularities with the method of combining the experiment and the finite element method (FEM), at last, achieve the optimization method of these parameters. That will not only get a stable effect of raising speed and shorten the debugging time greatly, but also promote the extensive application of the PM supporting mechanism in the ultra-high speed vertical rotors.

Highly efficient and stable cyclometalated ruthenium(II) complexes as sensitizers for dye-sensitized solar cells

International Nuclear Information System (INIS)

Huang, Jian-Feng; Liu, Jun-Min; Su, Pei-Yang; Chen, Yi-Fan; Shen, Yong; Xiao, Li-Min; Kuang, Dai-Bin; Su, Cheng-Yong

2015-01-01

Highlights: • Four novel thiocyanate-free cyclometalated ruthenium sensitizer were conveniently synthesized. • The D-CF 3 -sensitized DSSCs show higher efficiency compared to N719 based cells. • The DSSCs based on D-CF 3 and D-bisCF 3 sensitizers exhibit excellent long-term stability. • The diverse cyclometalated Ru complexes can be developed as high-performance sensitizers for use in DSSC. - Abstract: Four novel thiocyanate-free cyclometallted Ru(II) complexes, D-bisCF 3 , D-CF 3 , D-OMe, and D-DPA, with two 4,4′-dicarboxylic acid-2,2′-bipyridine together with a functionalized phenylpyridine ancillary ligand, have been designed and synthesized. The effect of different substituents (R = bisCF 3 , CF 3 , OMe, and DPA) on the ancillary C^N ligand on the photophysical properties and photovoltaic performance is investigated. Under standard global AM 1.5 solar conditions, the device based on D-CF 3 sensitizer gives a higher conversion efficiency of 8.74% than those based on D-bisCF 3 , D-OMe, and D-DPA, which can be ascribed to its broad range of visible light absorption, appropriate localization of the frontier orbitals, weak hydrogen bonds between -CF 3 and -OH groups at the TiO 2 surface, moderate dye loading on TiO 2 , and high charge collection efficiency. Moreover, the D-bisCF 3 and D-CF 3 based DSSCs exhibit good stability under 100 mW cm −2 light soaking at 60 °C for 400 h

Preparation and characterization of AuNPs/CNTs-ErGO electrochemical sensors for highly sensitive detection of hydrazine.

Science.gov (United States)

Zhao, Zhenting; Sun, Yongjiao; Li, Pengwei; Zhang, Wendong; Lian, Kun; Hu, Jie; Chen, Yong

2016-09-01

A highly sensitive electrochemical sensor of hydrazine has been fabricated by Au nanoparticles (AuNPs) coating of carbon nanotubes-electrochemical reduced graphene oxide composite film (CNTs-ErGO) on glassy carbon electrode (GCE). Cyclic voltammetry and potential amperometry have been used to investigate the electrochemical properties of the fabricated sensors for hydrazine detection. The performances of the sensors were optimized by varying the CNTs to ErGO ratio and the quantity of Au nanoparticles. The results show that under optimal conditions, a sensitivity of 9.73μAμM(-1)cm(-2), a short response time of 3s, and a low detection limit of 0.065μM could be achieved with a linear concentration response range from 0.3μM to 319μM. The enhanced electrochemical performances could be attributed to the synergistic effect between AuNPs and CNTs-ErGO film and the outstanding catalytic effect of the Au nanoparticles. Finally, the sensor was successfully used to analyse the tap water, showing high potential for practical applications. Copyright © 2016 Elsevier B.V. All rights reserved.

Achieving high aspect ratio wrinkles by modifying material network stress.

Science.gov (United States)

Chen, Yu-Cheng; Wang, Yan; McCarthy, Thomas J; Crosby, Alfred J

2017-06-07

Wrinkle aspect ratio, or the amplitude divided by the wavelength, is hindered by strain localization transitions when an increasing global compressive stress is applied to synthetic material systems. However, many examples from living organisms show extremely high aspect ratios, such as gut villi and flower petals. We use three experimental approaches to demonstrate that these high aspect ratio structures can be achieved by modifying the network stress in the wrinkle substrate. We modify the wrinkle stress and effectively delay the strain localization transition, such as folding, to larger aspect ratios by using a zero-stress initial wavy substrate, creating a secondary network with post-curing, or using chemical stress relaxation materials. A wrinkle aspect ratio as high as 0.85, almost three times higher than common values of synthetic wrinkles, is achieved, and a quantitative framework is presented to provide understanding the different strategies and predictions for future investigations.

Sensitivity Analysis of the Influence of Structural Parameters on Dynamic Behaviour of Highly Redundant Cable-Stayed Bridges

Directory of Open Access Journals (Sweden)

B. Asgari

2013-01-01

Full Text Available The model tuning through sensitivity analysis is a prominent procedure to assess the structural behavior and dynamic characteristics of cable-stayed bridges. Most of the previous sensitivity-based model tuning methods are automatic iterative processes; however, the results of recent studies show that the most reasonable results are achievable by applying the manual methods to update the analytical model of cable-stayed bridges. This paper presents a model updating algorithm for highly redundant cable-stayed bridges that can be used as an iterative manual procedure. The updating parameters are selected through the sensitivity analysis which helps to better understand the structural behavior of the bridge. The finite element model of Tatara Bridge is considered for the numerical studies. The results of the simulations indicate the efficiency and applicability of the presented manual tuning method for updating the finite element model of cable-stayed bridges. The new aspects regarding effective material and structural parameters and model tuning procedure presented in this paper will be useful for analyzing and model updating of cable-stayed bridges.

A Highly Sensitive Multicommuted Flow Analysis Procedure for Photometric Determination of Molybdenum in Plant Materials without a Solvent Extraction Step

Directory of Open Access Journals (Sweden)

Felisberto G. Santos

2017-01-01

Full Text Available A highly sensitive analytical procedure for photometric determination of molybdenum in plant materials was developed and validated. This procedure is based on the reaction of Mo(V with thiocyanate ions (SCN− in acidic medium to form a compound that can be monitored at 474 nm and was implemented employing a multicommuted flow analysis setup. Photometric detection was performed using an LED-based photometer coupled to a flow cell with a long optical path length (200 mm to achieve high sensitivity, allowing Mo(V determination at a level of μg L−1 without the use of an organic solvent extraction step. After optimization of operational conditions, samples of digested plant materials were analyzed employing the proposed procedure. The accuracy was assessed by comparing the obtained results with those of a reference method, with an agreement observed at 95% confidence level. In addition, a detection limit of 9.1 μg L−1, a linear response (r=0.9969 over the concentration range of 50–500 μg L−1, generation of only 3.75 mL of waste per determination, and a sampling rate of 51 determinations per hour were achieved.

Student self-esteem and academic achievement

Directory of Open Access Journals (Sweden)

Milošević Nikoleta M.

2005-01-01

Full Text Available There is a growing belief that academic achievement is the product of a complex network of teacher-student relations, where the identity of successful and unsuccessful student is developing with high, moderate or low self-esteem level. Self-esteem is most often defined as a conscious cognitive-affective expression of self-evaluation which is one of the most immediate indicators of self-concept integration degree. A number of authors view high self-esteem level as an important prerequisite for high academic achievement. In contrast, academic achievement and other experiences related to teaching and learning are considered to exert significant influence on self-esteem and a student should be successful at school first so as to develop a positive self-image and his academic abilities. The debate on what comes first - self-esteem or academic achievement - is in its character more academic than practical. This claim is supported by an increasing number of studies indicating the dynamism and reciprocity of correlation between academic achievement and self-esteem. The paper gives recommendations for educational practice to promote self-esteem and development of personal and social responsibility, which contributes to better student academic achievement. It is pointed out that teacher education in the field is necessary and that self-esteem and responsibility must become essential segments of curricula. Teacher is expected to become sensitive to the needs of students who are at risk to be unsuccessful and to largely apply cooperative learning methods. Findings demonstrate that cooperative learning either sustain or increase student self-esteem, whereas traditional teaching methods, in general, lead to its decline. Cooperative relations improve student self-image in respect of academic abilities and social interactions. Positive feedback, peer support, more frequent experience of learning achievement leads mainly to general increase in self-esteem and

Are inflationary predictions sensitive to very high energy physics?

International Nuclear Information System (INIS)

Burgess, C.P.; Lemieux, F.; Holman, R.; Cline, J.M.

2003-01-01

It has been proposed that the successful inflationary description of density perturbations on cosmological scales is sensitive to the details of physics at extremely high (trans-Planckian) energies. We test this proposal by examining how inflationary predictions depend on higher-energy scales within a simple model where the higher-energy physics is well understood. We find the best of all possible worlds: inflationary predictions are robust against the vast majority of high-energy effects, but can be sensitive to some effects in certain circumstances, in a way which does not violate ordinary notions of decoupling. This implies both that the comparison of inflationary predictions with CMB data is meaningful, and that it is also worth searching for small deviations from the standard results in the hopes of learning about very high energies. (author)

Automated microfluidically controlled electrochemical biosensor for the rapid and highly sensitive detection of Francisella tularensis.

Science.gov (United States)

Dulay, Samuel B; Gransee, Rainer; Julich, Sandra; Tomaso, Herbert; O'Sullivan, Ciara K

2014-09-15

Tularemia is a highly infectious zoonotic disease caused by a Gram-negative coccoid rod bacterium, Francisella tularensis. Tularemia is considered as a life-threatening potential biological warfare agent due to its high virulence, transmission, mortality and simplicity of cultivation. In the work reported here, different electrochemical immunosensor formats for the detection of whole F. tularensis bacteria were developed and their performance compared. An anti-Francisella antibody (FB11) was used for the detection that recognises the lipopolysaccharide found in the outer membrane of the bacteria. In the first approach, gold-supported self-assembled monolayers of a carboxyl terminated bipodal alkanethiol were used to covalently cross-link with the FB11 antibody. In an alternative second approach F(ab) fragments of the FB11 antibody were generated and directly chemisorbed onto the gold electrode surface. The second approach resulted in an increased capture efficiency and higher sensitivity. Detection limits of 4.5 ng/mL for the lipopolysaccharide antigen and 31 bacteria/mL for the F. tularensis bacteria were achieved. Having demonstrated the functionality of the immunosensor, an electrode array was functionalised with the antibody fragment and integrated with microfluidics and housed in a tester set-up that facilitated complete automation of the assay. The only end-user intervention is sample addition, requiring less than one-minute hands-on time. The use of the automated microfluidic set-up not only required much lower reagent volumes but also the required incubation time was considerably reduced and a notable increase of 3-fold in assay sensitivity was achieved with a total assay time from sample addition to read-out of less than 20 min. Copyright © 2014 Elsevier B.V. All rights reserved.

Desensitization protocol in highly HLA-sensitized and ABO-incompatible high titer kidney transplantation.

Science.gov (United States)

Uchida, J; Machida, Y; Iwai, T; Naganuma, T; Kitamoto, K; Iguchi, T; Maeda, S; Kamada, Y; Kuwabara, N; Kim, T; Nakatani, T

2010-12-01

A positive crossmatch indicates the presence of donor-specific alloantibodies and is associated with a graft loss rate of >80%; anti-ABO blood group antibodies develop in response to exposure to foreign blood groups, resulting in immediate graft loss. However, a desensitization protocol for highly HLA-sensitized and ABO-incompatible high-titer kidney transplantation has not yet been established. We treated 6 patients with high (≥1:512) anti-A/B antibody titers and 2 highly HLA-sensitized patients. Our immunosuppression protocol was initiated 1 month before surgery and included mycophenolate mofetil (1 g/d) and/or low-dose steroid (methylprednisolone 8 mg/d). Two doses of the anti-CD20 antibody rituximab (150 mg/m(2)) were administered 2 weeks before and on the day of transplantation. We performed antibody removal with 6-12 sessions of plasmapheresis (plasma exchange or double-filtration plasmapheresis) before transplantation. Splenectomy was also performed on the day of transplantation. Postoperative immunosuppression followed the same regimen as ABO-compatible cases, in which calcineurin inhibitors were initiated 3 days before transplantation, combined with 2 doses of basiliximab. Of the 8 patients, 7 subsequently underwent successful living-donor kidney transplantation. Follow-up of our recipients showed that the patient and graft survival rates were 100%. Acute cellular rejection and antibody-mediated rejection episodes occurred in 1 of the 7 recipients. These findings suggest that our immunosuppression regimen consisting of rituximab infusions, splenectomy, plasmapheresis, and pharmacologic immunosuppression may prove to be effective as a desensitization protocol for highly HLA-sensitized and ABO-incompatible high-titer kidney transplantation. Copyright © 2010 Elsevier Inc. All rights reserved.

Multi-Service Highly Sensitive Rectifier for Enhanced RF Energy Scavenging

Science.gov (United States)

Shariati, Negin; Rowe, Wayne S. T.; Scott, James R.; Ghorbani, Kamran

2015-01-01

Due to the growing implications of energy costs and carbon footprints, the need to adopt inexpensive, green energy harvesting strategies are of paramount importance for the long-term conservation of the environment and the global economy. To address this, the feasibility of harvesting low power density ambient RF energy simultaneously from multiple sources is examined. A high efficiency multi-resonant rectifier is proposed, which operates at two frequency bands (478–496 and 852–869 MHz) and exhibits favorable impedance matching over a broad input power range (−40 to −10 dBm). Simulation and experimental results of input reflection coefficient and rectified output power are in excellent agreement, demonstrating the usefulness of this innovative low-power rectification technique. Measurement results indicate an effective efficiency of 54.3%, and an output DC voltage of 772.8 mV is achieved for a multi-tone input power of −10 dBm. Furthermore, the measured output DC power from harvesting RF energy from multiple services concurrently exhibits a 3.14 and 7.24 fold increase over single frequency rectification at 490 and 860 MHz respectively. Therefore, the proposed multi-service highly sensitive rectifier is a promising technique for providing a sustainable energy source for low power applications in urban environments. PMID:25951137

Simultaneous stability and sensitivity in model cortical networks is achieved through anti-correlations between the in- and out-degree of connectivity

Directory of Open Access Journals (Sweden)

Juan Carlos Vasquez

2013-11-01

Full Text Available Neuronal networks in rodent barrel cortex are characterized by stable low baseline firing rates. However, they are sensitive to the action potentials of single neurons as suggested by recent single-cell stimulation experiments that report quantifiable behavioral responses in response to short spike trains elicited in single neurons. Hence, these networks are stable against internally generated fluctuations in firing rate but at the same time remain sensitive to similarly-sized externally induced perturbations. We investigated stability and sensitivity in a simple recurrent network of stochastic binary neurons and determined numerically the effects of correlation between the number of afferent (‘in-degree’ and efferent (‘out-degree’ connections in neurons. The key advance reported in this work is that anti-correlation between in-/out-degree distributions increased the stability of the network in comparison to networks with no correlation or positive correlations, while being able to achieve the same level of sensitivity. The experimental characterization of degree distributions is difficult because all presynaptic and postsynaptic neurons have to be identified and counted. We explored whether the statistics of network motifs, which requires the characterization of connections between small subsets of neurons, could be used to detect evidence for degree anti-correlations. We find that the sample frequency of the 3-neuron ‘ring’ motif (1→2→3→1, can be used to detect degree anti-correlation for sub-networks of size 30 using about 50 samples, which is of significance because the necessary measurements are achievable experimentally in the near future.Taken together, we hypothesize that barrel cortex networks exhibit degree anti-correlations and specific network motif statistics.

Sensitivity Enhancement in Si Nanophotonic Waveguides Used for Refractive Index Sensing

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Yaocheng Shi

2016-03-01

Full Text Available A comparative study is given for the sensitivity of several typical Si nanophotonic waveguides, including SOI (silicon-on-insulator nanowires, nanoslot waveguides, suspended Si nanowires, and nanofibers. The cases for gas sensing (ncl ~ 1.0 and liquid sensing (ncl ~ 1.33 are considered. When using SOI nanowires (with a SiO2 buffer layer, the sensitivity for liquid sensing (S ~ 0.55 is higher than that for gas sensing (S ~ 0.35 due to lower asymmetry in the vertical direction. By using SOI nanoslot waveguides, suspended Si nanowires, and Si nanofibers, one could achieve a higher sensitivity compared to sensing with a free-space beam (S = 1.0. The sensitivity for gas sensing is higher than that for liquid sensing due to the higher index-contrast. The waveguide sensitivity of an optimized suspended Si nanowire for gas sensing is as high as 1.5, which is much higher than that of a SOI nanoslot waveguide. Furthermore, the optimal design has very large tolerance to the core width variation due to the fabrication error (∆w ~ ±50 nm. In contrast, a Si nanofiber could also give a very high sensitivity (e.g., ~1.43 while the fabrication tolerance is very small (i.e., ∆w < ±5 nm. The comparative study shows that suspended Si nanowire is a good choice to achieve ultra-high waveguide sensitivity.

High-Quality GaN Epilayers Achieved by Facet-Controlled Epitaxial Lateral Overgrowth on Sputtered AlN/PSS Templates.

Science.gov (United States)

He, Chenguang; Zhao, Wei; Zhang, Kang; He, Longfei; Wu, Hualong; Liu, Ningyang; Zhang, Shan; Liu, Xiaoyan; Chen, Zhitao

2017-12-13

It is widely believed that the lack of high-quality GaN wafers severely hinders the progress in GaN-based devices, especially for defect-sensitive devices. Here, low-cost AlN buffer layers were sputtered on cone-shaped patterned sapphire substrates (PSSs) to obtain high-quality GaN epilayers. Without any mask or regrowth, facet-controlled epitaxial lateral overgrowth was realized by metal-organic chemical vapor deposition. The uniform coating of the sputtered AlN buffer layer and the optimized multiple modulation guaranteed high growth selectivity and uniformity of the GaN epilayer. As a result, an extremely smooth surface was achieved with an average roughness of 0.17 nm over 3 × 3 μm 2 . It was found that the sputtered AlN buffer layer could significantly suppress dislocations on the cones. Moreover, the optimized three-dimensional growth process could effectively promote dislocation bending. Therefore, the threading dislocation density (TDD) of the GaN epilayer was reduced to 4.6 × 10 7 cm -2 , which is about an order of magnitude lower than the case of two-step GaN on the PSS. In addition, contamination and crack in the light-emitting diode fabricated on the obtained GaN were also effectively suppressed by using the sputtered AlN buffer layer. All of these advantages led to a high output power of 116 mW at 500 mA with an emission wavelength of 375 nm. This simple, yet effective growth technique is believed to have great application prospects in high-performance TDD-sensitive optoelectronic and electronic devices.

Sensitivity-Bandwidth Limit in a Multimode Optoelectromechanical Transducer

Science.gov (United States)

Moaddel Haghighi, I.; Malossi, N.; Natali, R.; Di Giuseppe, G.; Vitali, D.

2018-03-01

An optoelectromechanical system formed by a nanomembrane capacitively coupled to an L C resonator and to an optical interferometer has recently been employed for the highly sensitive optical readout of rf signals [T. Bagci et al., Nature (London) 507, 81 (2013), 10.1038/nature13029]. We propose and experimentally demonstrate how the bandwidth of such a transducer can be increased by controlling the interference between two electromechanical interaction pathways of a two-mode mechanical system. With a proof-of-principle device operating at room temperature, we achieve a sensitivity of 300 nV /√{Hz } over a bandwidth of 15 kHz in the presence of radio-frequency noise, and an optimal shot-noise-limited sensitivity of 10 nV /√{Hz } over a bandwidth of 5 kHz. We discuss strategies for improving the performance of the device, showing that, for the same given sensitivity, a mechanical multimode transducer can achieve a bandwidth significantly larger than that for a single-mode one.

Depleted Nanocrystal-Oxide Heterojunctions for High-Sensitivity Infrared Detection

Science.gov (United States)

2015-08-28

Approved for Public Release; Distribution Unlimited Final Report: 4.3 Electronic Sensing - Depleted Nanocrystal- Oxide Heterojunctions for High...reviewed journals: Final Report: 4.3 Electronic Sensing - Depleted Nanocrystal- Oxide Heterojunctions for High-Sensitivity Infrared Detection Report Title...PERCENT_SUPPORTEDNAME FTE Equivalent: Total Number: 1 1 Final Progress Report Project title: Depleted Nanocrystal- Oxide Heterojunctions for High

N -annulated perylene-based push-pull-type sensitizers

KAUST Repository

Qi, Qingbiao; Wang, Xingzhu; Fan, Li; Zheng, Bin; Zeng, Wangdong; Luo, Jie; Huang, Kuo-Wei; Wang, Qing; Wu, Jishan

2015-01-01

Alkoxy-wrapped N-annulated perylene (NP) was synthesized and used as a rigid and coplanar π-linker for three push-pull type metal-free sensitizers QB1-QB3. Their optical and electrochemical properties were tuned by varying the structure of acceptor. These new dyes were applied in Co(II)/(III) based dye-sensitized solar cells, and power conversion efficiency up to 6.95% was achieved, indicating that NP could be used as a new building block for the design of high-performance sensitizers in the future.

N -annulated perylene-based push-pull-type sensitizers

KAUST Repository

Qi, Qingbiao

2015-02-06

Alkoxy-wrapped N-annulated perylene (NP) was synthesized and used as a rigid and coplanar π-linker for three push-pull type metal-free sensitizers QB1-QB3. Their optical and electrochemical properties were tuned by varying the structure of acceptor. These new dyes were applied in Co(II)/(III) based dye-sensitized solar cells, and power conversion efficiency up to 6.95% was achieved, indicating that NP could be used as a new building block for the design of high-performance sensitizers in the future.

Psychosocial aspects and management of evaluation in secondary high and low achievement

Directory of Open Access Journals (Sweden)

Alicia Rivera Morales

2017-01-01

Full Text Available This article describes a segment of a broader study of mixed cut occurs. In this space only part of the qualitative analysis is recovered around the psychosocial aspects that influence the management of the evaluation results from the application of semi-structured interviews and focus groups with 80 senior secondary schools with high and low achievement located in four states of Mexico: Sonora, Durango, Mexico City and Oaxaca. The findings are presented from categories they consider the meaning, beliefs and expectations about evaluation and how these aspects influence the actions of the directors of the schools studied. Polarized cases allow, in their contrasts, identify processes and factors that mark the differences or similarities between them. Thus it was found that school principals low achievement hope to change the attitude of teachers towards the assessment, expect supervisors to monitor teachers and external support (specialists that indicate how to evaluate them. Moreover, the idea that a school with high achievement is an organization that promotes the participation director, has high expectations of students and teachers, its management system and decision-making can achieve the objectives set, and reasserts Assessment proposes actions that seek continuous improvement.

The relationships between the achievement motivations and temperaments of psychology students with different lateral organization profiles.

Directory of Open Access Journals (Sweden)

Vorobyeva E.V.

2015-03-01

Full Text Available The objective of this research was to assess the motivational potential of psychology students using an egoskopiya method. Heart rate and EEG data were recorded while the participants performed the Mehrabian achievement motivation test. Thirty students of the Faculty of Psychology of Southern Federal University who were aged between 20 and 30 years participated. The psychodiagnostic study involved 136 students from the Faculty of Psychology of Southern Federal University who were aged between 18 and 49 years. To determine the lateral organization profiles of sensory and motor functions, a computer-based testing program termed “Profile” was used. The Compact Russian Structure of Temperament Questionnaire (STQ-77 was used to evaluate the features of temperament. The results revealed that people with a strong motivation to succeed exhibited a predominance of right features in their lateral organization profiles. Their cardiovascular systems were in more activated states than those of the people who were extremely motivated to avoid failure. The observed temperament features of psychology students with different levels of achievement motivation indicated that the level of achievement motivation is related to the properties of temperament such that students with lower levels of achievement motivation (i.e., motivation to avoid failure exhibited the temperament traits of Neuroticism and Impulsivity in addition to low values on the scales for the Sensitivity to Sensations, Intellectual Ergonicity, and Sensitivity to Probabilities. High levels of achievement motivation (i.e., motivation to strive toward success corresponded to the psychology students’ propensities for Sensitivity to Sensations, high levels of Intellectual Ergonicity, high levels of Sensitivity to Probabilities and low values on the scales of Impulsivity and Neuroticism.

A highly sensitive and specific capacitive aptasensor for rapid and label-free trace analysis of Bisphenol A (BPA) in canned foods.

Science.gov (United States)

Mirzajani, Hadi; Cheng, Cheng; Wu, Jayne; Chen, Jiangang; Eda, Shigotoshi; Najafi Aghdam, Esmaeil; Badri Ghavifekr, Habib

2017-03-15

A rapid, highly sensitive, specific and low-cost capacitive affinity biosensor is presented here for label-free and single step detection of Bisphenol A (BPA). The sensor design allows rapid prototyping at low-cost using printed circuit board material by benchtop equipment. High sensitivity detection is achieved through the use of a BPA-specific aptamer as probe molecule and large electrodes to enhance AC-electroelectrothermal effect for long-range transport of BPA molecules toward electrode surface. Capacitive sensing technique is used to determine the bounded BPA level by measuring the sample/electrode interfacial capacitance of the sensor. The developed biosensor can detect BPA level in 20s and exhibits a large linear range from 1 fM to 10 pM, with a limit of detection (LOD) of 152.93 aM. This biosensor was applied to test BPA in canned food samples and could successfully recover the levels of spiked BPA. This sensor technology is demonstrated to be highly promising and reliable for rapid, sensitive and on-site monitoring of BPA in food samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Sensitive detection of nanomechanical motion using piezoresistive signal downmixing

International Nuclear Information System (INIS)

Bargatin, I.; Myers, E.B.; Arlett, J.; Gudlewski, B.; Roukes, M.L.

2005-01-01

We have developed a method of measuring rf-range resonance properties of nanoelectromechanical systems (NEMS) with integrated piezoresistive strain detectors serving as signal downmixers. The technique takes advantage of the high strain sensitivity of semiconductor-based piezoresistors, while overcoming the problem of rf signal attenuation due to a high source impedance. Our technique also greatly reduces the effect of the cross-talk between the detector and actuator circuits. We achieve thermomechanical noise detection of cantilever resonance modes up to 71 MHz at room temperature, demonstrating that downmixed piezoresistive signal detection is a viable high-sensitivity method of displacement detection in high-frequency NEMS

Self-Esteem and Academic Achievement of High School Students

Science.gov (United States)

Moradi Sheykhjan, Tohid; Jabari, Kamran; Rajeswari, K.

2014-01-01

The primary purpose of this study was to determine the influence of self-esteem on academic achievement among high school students in Miandoab City of Iran. The methodology of the research is descriptive and correlation that descriptive and inferential statistics were used to analyze the data. Statistical Society includes male and female high…

Utilizing leadership to achieve high reliability in the delivery of perinatal care

Directory of Open Access Journals (Sweden)

Parrotta C

2012-11-01

Full Text Available Carmen Parrotta,1 William Riley,1 Les Meredith21School of Public Health, University of Minnesota, Minneapolis, MN, 2Premier Insurance Management Services Inc, Charlotte, NC, USAAbstract: Highly reliable care requires standardization of clinical practices and is a prerequisite for patient safety. However, standardization in complex hospital settings is extremely difficult to attain and health care leaders are challenged to create care delivery processes that ensure patient safety. Moreover, once high reliability is achieved in a hospital unit, it must be maintained to avoid process deterioration. This case study examines an intervention to implement care bundles (a collection of evidence-based practices in four hospitals to achieve standardized care in perinatal units. The results show different patterns in the rate and magnitude of change within the hospitals to achieve high reliability. The study is part of a larger nationwide study of 16 hospitals to improve perinatal safety. Based on the findings, we discuss the role of leadership for implementing and sustaining high reliability to ensure freedom from unintended injury.Keywords: care bundles, evidence-based practice, standardized care, process improvement

The effects of modeling instruction on high school physics academic achievement

Science.gov (United States)

Wright, Tiffanie L.

The purpose of this study was to explore whether Modeling Instruction, compared to traditional lecturing, is an effective instructional method to promote academic achievement in selected high school physics classes at a rural middle Tennessee high school. This study used an ex post facto , quasi-experimental research methodology. The independent variables in this study were the instructional methods of teaching. The treatment variable was Modeling Instruction and the control variable was traditional lecture instruction. The Treatment Group consisted of participants in Physical World Concepts who received Modeling Instruction. The Control Group consisted of participants in Physical Science who received traditional lecture instruction. The dependent variable was gains scores on the Force Concepts Inventory (FCI). The participants for this study were 133 students each in both the Treatment and Control Groups (n = 266), who attended a public, high school in rural middle Tennessee. The participants were administered the Force Concepts Inventory (FCI) prior to being taught the mechanics of physics. The FCI data were entered into the computer-based Statistical Package for the Social Science (SPSS). Two independent samples t-tests were conducted to answer the research questions. There was a statistically significant difference between the treatment and control groups concerning the instructional method. Modeling Instructional methods were found to be effective in increasing the academic achievement of students in high school physics. There was no statistically significant difference between FCI gains scores for gender. Gender was found to have no effect on the academic achievement of students in high school physics classes. However, even though there was not a statistically significant difference, female students' gains scores were higher than male students' gains scores when Modeling Instructional methods of teaching were used. Based on these findings, it is recommended

Serine Protease Zymography: Low-Cost, Rapid, and Highly Sensitive RAMA Casein Zymography.

Science.gov (United States)

Yasumitsu, Hidetaro

2017-01-01

To detect serine protease activity by zymography, casein and CBB stain have been used as a substrate and a detection procedure, respectively. Casein zymography has been using substrate concentration at 1 mg/mL and employing conventional CBB stain. Although ordinary casein zymography provides reproducible results, it has several disadvantages including time-consuming and relative low sensitivity. Improved casein zymography, RAMA casein zymography, is rapid and highly sensitive. RAMA casein zymography completes the detection process within 1 h after incubation and increases the sensitivity at least by tenfold. In addition to serine protease, the method also detects metalloprotease 7 (MMP7, Matrilysin) with high sensitivity.

Subnanometer Ga 2 O 3 Tunnelling Layer by Atomic Layer Deposition to Achieve 1.1 V Open-Circuit Potential in Dye-Sensitized Solar Cells

KAUST Repository

Chandiran, Aravind Kumar; Tetreault, Nicolas; Humphry-Baker, Robin; Kessler, Florian; Baranoff, Etienne; Yi, Chenyi; Nazeeruddin, Mohammad Khaja; Grä tzel, Michael

2012-01-01

Herein, we present the first use of a gallium oxide tunnelling layer to significantly reduce electron recombination in dye-sensitized solar cells (DSC). The subnanometer coating is achieved using atomic layer deposition (ALD) and leading to a new

Highly sensitive C-reactive protein (CRP) assay using metal-enhanced fluorescence (MEF)

International Nuclear Information System (INIS)

Zhang, Yi; Keegan, Gemma L.; Stranik, Ondrej; Brennan-Fournet, Margaret E.; McDonagh, Colette

2015-01-01

Fluorescence has been extensively employed in the area of diagnostic immunoassays. A significant enhancement of fluorescence can be achieved when noble metal nanoparticles are placed in close proximity to fluorophores. This effect, referred to as metal-enhanced fluorescence (MEF), has the potential to produce immunoassays with a high sensitivity and a low limit of detection (LOD). In this study, we investigate the fluorescence enhancement effect of two different nanoparticle systems, large spherical silver nanoparticles (AgNPs) and gold edge-coated triangular silver nanoplates, and both systems were evaluated for MEF. The extinction properties and electric field enhancement of both systems were modeled, and the optimum system, spherical AgNPs, was used in a sandwich immunoassay for human C-reactive protein with a red fluorescent dye label. A significant enhancement in the fluorescence was observed, which corresponded to an LOD improvement of ∼19-fold compared to a control assay without AgNPs

Highly sensitive C-reactive protein (CRP) assay using metal-enhanced fluorescence (MEF)

Energy Technology Data Exchange (ETDEWEB)

Zhang, Yi; Keegan, Gemma L., E-mail: gemmakeegan@gmail.com [Dublin City University, School of Physical Sciences, Biomedical Diagnostics Institute (Ireland); Stranik, Ondrej [Leibniz Institute of Photonic Technology, Department of NanoBiophotonics (Germany); Brennan-Fournet, Margaret E. [CMP-EMSE, MOC, Department of Bioelectronics, Ecole Nationale Superieure des Mines (France); McDonagh, Colette [Dublin City University, School of Physical Sciences, Biomedical Diagnostics Institute (Ireland)

2015-07-15

Fluorescence has been extensively employed in the area of diagnostic immunoassays. A significant enhancement of fluorescence can be achieved when noble metal nanoparticles are placed in close proximity to fluorophores. This effect, referred to as metal-enhanced fluorescence (MEF), has the potential to produce immunoassays with a high sensitivity and a low limit of detection (LOD). In this study, we investigate the fluorescence enhancement effect of two different nanoparticle systems, large spherical silver nanoparticles (AgNPs) and gold edge-coated triangular silver nanoplates, and both systems were evaluated for MEF. The extinction properties and electric field enhancement of both systems were modeled, and the optimum system, spherical AgNPs, was used in a sandwich immunoassay for human C-reactive protein with a red fluorescent dye label. A significant enhancement in the fluorescence was observed, which corresponded to an LOD improvement of ∼19-fold compared to a control assay without AgNPs.

Application of MoS{sub 2} modified screen-printed electrodes for highly sensitive detection of bovine serum albumin

Energy Technology Data Exchange (ETDEWEB)

Kukkar, Manil [Central Scientific Instruments Organisation (CSIR-CSIO), Sector 30-C, Chandigarh, 160030 (India); Academy of Scientific and Innovative Research, CSIR-CSIO, Sector 30-C, Chandigarh, 160030 (India); Sharma, Ashish [Central Scientific Instruments Organisation (CSIR-CSIO), Sector 30-C, Chandigarh, 160030 (India); UIET, Panjab University, Sector 14, Chandigarh, 160014 (India); Kumar, Parveen [Department of Biotechnology, Kurukshetra University, Kurukshetra, 136119 (India); Kim, Ki-Hyun, E-mail: kkim61@hanyang.ac.kr [Department of Civil & Environmental Engineering, Hanyang University, 222 Wangsimni-Ro, Seoul 04763 (Korea, Republic of); Deep, Akash, E-mail: dr.akashdeep@csio.res.in [Central Scientific Instruments Organisation (CSIR-CSIO), Sector 30-C, Chandigarh, 160030 (India); Academy of Scientific and Innovative Research, CSIR-CSIO, Sector 30-C, Chandigarh, 160030 (India)

2016-10-05

The present work reports the application of a new molybdenum disulphide (MoS{sub 2})-based electrochemical platform for highly sensitive quantitation of an iron-binding protein, bovine serum albumin (BSA). The gold screen-printed electrodes were modified with MoS{sub 2} nanoflakes, followed by bioconjugation with anti-BSA antibodies. Using the above bioelectrode, cyclic voltammetric analysis was carried out in the presence of a Fe{sup 3+}/Fe{sup 2+} redox probe which exhibited a linear response of peak current with varying concentrations of BSA up to 10 ng/mL (with a detection limit of 0.006 ng/mL). This study is novel in that it shows a considerable enhancement of signal during electrochemical sensing of a protein. - Highlights: • MoS{sub 2} nanoflakes have been used for an electrochemical immunosensor. • The sensor's response was proportional to the antigen concentration. • Highly sensitive and specific detection of iron-binding protein ‘BSA’ is achieved. • A wide linear range of detection of BSA is demonstrated.

Aluminum nano-cantilevers for high sensitivity mass sensors

DEFF Research Database (Denmark)

Davis, Zachary James; Boisen, Anja

2005-01-01

We have fabricated Al nano-cantilevers using a very simple one mask contact UV lithography technique with lateral dimensions under 500 nm and vertical dimensions of approximately 100 nm. These devices are demonstrated as highly sensitive mass sensors by measuring their dynamic properties. Further...

Atomic absorption determination of ultratrace tellurium in rocks utilizing high sensitivity sampling systems

International Nuclear Information System (INIS)

Beaty, R.D.

1973-01-01

The sampling boat and the graphite furnace were shown to possess the required sensitivity to detect tellurium at ultratrace levels, in a variety of sample types, by atomic absorption. In the sampling boat approach, tellurium in sample solutions is chemically separated and concentrated by extraction into methyl isobutyl ketone before measurement. For samples exhibiting extraction interferences or excessively high background absorption, a preliminary separation of tellurium by coprecipitation with selenium is described. Using this technique, tellurium can be quantitatively detected down to 5 nanograms and linear response is observed to 100 nanograms. Relative standard deviations of better than 7 percent are achieved for 50 nanograms of tellurium. For samples that have a tellurium content below the detection limits of the sampling boat, the graphite furnace is used for atomization. By this method, as little as 0.07 nanograms of tellurium can be detected, and a precision of 1 percent relative standard deviation is achievable at the 5 nanogram level. A routinely applicable procedure was developed for determining tellurium in rocks, using the graphite furnace, after a hydrofluoric acid decomposition of the sample. Using this procedure, tellurium data were obtained on 20 different rocks, and the significance of this new information is discussed. (Diss. Abstr. Int., B)

Parent Involvement Practices of High-Achieving Elementary Science Students

Science.gov (United States)

Waller, Samara Susan

This study addressed a prevalence of low achievement in science courses in an urban school district in Georgia. National leaders and educators have identified the improvement of science proficiency as critical to the future of American industry. The purpose of this study was to examine parent involvement in this school district and its contribution to the academic achievement of successful science students. Social capital theory guided this study by suggesting that students achieve best when investments are made into their academic and social development. A collective case study qualitative research design was used to interview 9 parent participants at 2 elementary schools whose children scored in the exceeds category on the Science CRCT. The research questions focused on what these parents did at home to support their children's academic achievement. Data were collected using a semi-structured interview protocol and analyzed through the categorical aggregation of transcribed interviews. Key findings revealed that the parents invested time and resources in 3 practices: communicating high expectations, supporting and developing key skills, and communicating with teachers. These findings contribute to social change at both the local and community level by creating a starting point for teachers, principals, and district leaders to reexamine the value of parent input in the educational process, and by providing data to support the revision of current parent involvement policies. Possibilities for further study building upon the findings of this study may focus on student perceptions of their parents' parenting as it relates to their science achievement.

Prototype of high resolution PET using resistive electrode position sensitive CdTe detectors

International Nuclear Information System (INIS)

Kikuchi, Yohei; Ishii, Keizo; Matsuyama, Shigeo; Yamazaki, Hiromichi

2008-01-01

Downsizing detector elements makes it possible that spatial resolutions of positron emission tomography (PET) cameras are improved very much. From this point of view, semiconductor detectors are preferable. To obtain high resolution, the pixel type or the multi strip type of semiconductor detectors can be used. However, in this case, there is a low packing ratio problem, because a dead area between detector arrays cannot be neglected. Here, we propose the use of position sensitive semiconductor detectors with resistive electrode. The CdTe detector is promising as a detector for PET camera because of its high sensitivity. In this paper, we report development of prototype of high resolution PET using resistive electrode position sensitive CdTe detectors. We made 1-dimensional position sensitive CdTe detectors experimentally by changing the electrode thickness. We obtained 750 A as an appropriate thickness of position sensitive detectors, and evaluated the performance of the detector using a collimated 241 Am source. A good position resolution of 1.2 mm full width half maximum (FWHM) was obtained. On the basis of the fundamental development of resistive electrode position sensitive detectors, we constructed a prototype of high resolution PET which was a dual head type and was consisted of thirty-two 1-dimensional position sensitive detectors. In conclusion, we obtained high resolutions which are 0.75 mm (FWHM) in transaxial, and 1.5 mm (FWHM) in axial. (author)

Low Cost, Low Power, High Sensitivity Magnetometer

Science.gov (United States)

2008-12-01

which are used to measure the small magnetic signals from brain. Other types of vector magnetometers are fluxgate , coil based, and magnetoresistance...concentrator with the magnetometer currently used in Army multimodal sensor systems, the Brown fluxgate . One sees the MEMS fluxgate magnetometer is...Guedes, A.; et al., 2008: Hybrid - LOW COST, LOW POWER, HIGH SENSITIVITY MAGNETOMETER A.S. Edelstein*, James E. Burnette, Greg A. Fischer, M.G

Highly sensitive assay for tyrosine hydroxylase activity by high-performance liquid chromatography.

Science.gov (United States)

Nagatsu, T; Oka, K; Kato, T

1979-07-21

A highly sensitive assay for tyrosine hydroxylase (TH) activity by high-performance liquid chromatography (HPLC) with amperometric detection was devised based on the rapid isolation of enzymatically formed DOPA by a double-column procedure, the columns fitted together sequentially (the top column of Amberlite CG-50 and the bottom column of aluminium oxide). DOPA was adsorbed on the second aluminium oxide column, then eluted with 0.5 M hydrochloric acid, and assayed by HPLC with amperometric detection. D-Tyrosine was used for the control. alpha-Methyldopa was added to the incubation mixture as an internal standard after incubation. This assay was more sensitive than radioassays and 5 pmol of DOPA formed enzymatically could be measured in the presence of saturating concentrations of tyrosine and 6-methyltetrahydropterin. The TH activity in 2 mg of human putamen could be easily measured, and this method was found to be particularly suitable for the assay of TH activity in a small number of nuclei from animal and human brain.

Sensitive high performance liquid chromatographic method for the ...

African Journals Online (AJOL)

A new simple, sensitive, cost-effective and reproducible high performance liquid chromatographic (HPLC) method for the determination of proguanil (PG) and its metabolites, cycloguanil (CG) and 4-chlorophenylbiguanide (4-CPB) in urine and plasma is described. The extraction procedure is a simple three-step process ...

Review of high-sensitivity Radon studies

Science.gov (United States)

Wojcik, M.; Zuzel, G.; Simgen, H.

2017-10-01

A challenge in many present cutting-edge particle physics experiments is the stringent requirements in terms of radioactive background. In peculiar, the prevention of Radon, a radioactive noble gas, which occurs from ambient air and it is also released by emanation from the omnipresent progenitor Radium. In this paper we review various high-sensitivity Radon detection techniques and approaches, applied in the experiments looking for rare nuclear processes happening at low energies. They allow to identify, quantitatively measure and finally suppress the numerous sources of Radon in the detectors’ components and plants.

Recent trends in high spin sensitivity magnetic resonance

Science.gov (United States)

Blank, Aharon; Twig, Ygal; Ishay, Yakir

2017-07-01

new ideas, show how these limiting factors can be mitigated to significantly improve the sensitivity of induction detection. Finally, we outline some directions for the possible applications of high-sensitivity induction detection in the field of electron spin resonance.

CaSO4:DY,Mn: A new and highly sensitive thermoluminescence phosphor for versatile dosimetry

Science.gov (United States)

Bahl, Shaila; Lochab, S. P.; Kumar, Pratik

2016-02-01

With the advent of newer techniques for dose reduction coupled with the development of more sensitive detectors, the radiation doses in radiological medical investigation are decreasing. Nevertheless, keeping the tenet in mind that all radiation doses could entail risk, there is a need to develop more sensitive dosimeters capable of measuring low doses. This paper gives the account of the development of a new and sensitive phosphor CaSO4:Dy,Mn and its characterization. The standard production procedure based on the recrystallization method was used to prepare CaSO4:Dy,Mn. The Thermoluminescence (TL) studies were carried out by exposing it with gamma radiation (Cs-137) from 10 μGy to 100 Gy. The theoretical studies to determine the number of peaks and kinetic parameters related to the TL glow peaks in CaSO4:Dy,Mn was performed using the Computerized Glow Curve Deconvolution (CGCD) method. Experiments were performed to determine optimum concentration of the dopants Dysprosium (Dy) and Mangnese (Mn) in the host CaSO4 so that maximum sensitivity of the phosphor may be achieved. The optimum dopant concentration turned out to be 0.1 mol%. As there were two dopants Dy and Mn their relative ratio were varied in steps of 0.025 keeping the concentration of total dopant (Dy and Mn) 0.1 mol% always. The maximum TL intensity was seen in the CaSO4:Dy(0.025),Mn(0.075) combination. The TL sensitivity of this phosphor was found to be about 2 and 1.8 times higher than that of popular phosphor CaSO4:Dy and LiF:Mg,Cu,P (TLD-700H) respectively. This new phosphor CaSO4:Dy,Mn showed fading of 11% which is similar to that of the standard phosphor CaSO4:Dy. The paper concludes that the new, highly sensitive TL phosphor CaSO4:Dy,Mn has shown higher sensitivity and hence the potential to replace commonly used CaSO4:Dy.

High fat diet promotes achievement of peak bone mass in young rats

Energy Technology Data Exchange (ETDEWEB)

Malvi, Parmanand; Piprode, Vikrant; Chaube, Balkrishna; Pote, Satish T. [National Centre for Cell Science, Savitribai Phule Pune University Campus, Ganeshkhind, Pune 411 007 (India); Mittal, Monika; Chattopadhyay, Naibedya [Division of Endocrinology and Center for Research in Anabolic Skeletal Targets in Health and Illness (ASTHI), CSIR-Central Drug Research Institute, Jankipuram Extension, Sitapur Road, Lucknow 226 031 (India); Wani, Mohan R. [National Centre for Cell Science, Savitribai Phule Pune University Campus, Ganeshkhind, Pune 411 007 (India); Bhat, Manoj Kumar, E-mail: manojkbhat@nccs.res.in [National Centre for Cell Science, Savitribai Phule Pune University Campus, Ganeshkhind, Pune 411 007 (India)

2014-12-05

Highlights: • High fat diet helps in achieving peak bone mass at younger age. • Shifting from high fat to normal diet normalizes obese parameters. • Bone parameters are sustained even after withdrawal of high fat diet. - Abstract: The relationship between obesity and bone is complex. Epidemiological studies demonstrate positive as well as negative correlation between obesity and bone health. In the present study, we investigated the impact of high fat diet-induced obesity on peak bone mass. After 9 months of feeding young rats with high fat diet, we observed obesity phenotype in rats with increased body weight, fat mass, serum triglycerides and cholesterol. There were significant increases in serum total alkaline phosphatase, bone mineral density and bone mineral content. By micro-computed tomography (μ-CT), we observed a trend of better trabecular bones with respect to their microarchitecture and geometry. This indicated that high fat diet helps in achieving peak bone mass and microstructure at younger age. We subsequently shifted rats from high fat diet to normal diet for 6 months and evaluated bone/obesity parameters. It was observed that after shifting rats from high fat diet to normal diet, fat mass, serum triglycerides and cholesterol were significantly decreased. Interestingly, the gain in bone mineral density, bone mineral content and trabecular bone parameters by HFD was retained even after body weight and obesity were normalized. These results suggest that fat rich diet during growth could accelerate achievement of peak bone mass that is sustainable even after withdrawal of high fat diet.

High fat diet promotes achievement of peak bone mass in young rats

International Nuclear Information System (INIS)

Malvi, Parmanand; Piprode, Vikrant; Chaube, Balkrishna; Pote, Satish T.; Mittal, Monika; Chattopadhyay, Naibedya; Wani, Mohan R.; Bhat, Manoj Kumar

2014-01-01

Highlights: • High fat diet helps in achieving peak bone mass at younger age. • Shifting from high fat to normal diet normalizes obese parameters. • Bone parameters are sustained even after withdrawal of high fat diet. - Abstract: The relationship between obesity and bone is complex. Epidemiological studies demonstrate positive as well as negative correlation between obesity and bone health. In the present study, we investigated the impact of high fat diet-induced obesity on peak bone mass. After 9 months of feeding young rats with high fat diet, we observed obesity phenotype in rats with increased body weight, fat mass, serum triglycerides and cholesterol. There were significant increases in serum total alkaline phosphatase, bone mineral density and bone mineral content. By micro-computed tomography (μ-CT), we observed a trend of better trabecular bones with respect to their microarchitecture and geometry. This indicated that high fat diet helps in achieving peak bone mass and microstructure at younger age. We subsequently shifted rats from high fat diet to normal diet for 6 months and evaluated bone/obesity parameters. It was observed that after shifting rats from high fat diet to normal diet, fat mass, serum triglycerides and cholesterol were significantly decreased. Interestingly, the gain in bone mineral density, bone mineral content and trabecular bone parameters by HFD was retained even after body weight and obesity were normalized. These results suggest that fat rich diet during growth could accelerate achievement of peak bone mass that is sustainable even after withdrawal of high fat diet

Novel charge sensitive preamplifier without high-value feedback resistor

International Nuclear Information System (INIS)

Xi Deming

1992-01-01

A novel charge sensitive preamplifier is introduced. The method of removing the high value feedback resistor, the circuit design and analysis are described. A practical circuit and its measured performances are provided

BH3105 type neutron dose equivalent meter of high sensitivity

International Nuclear Information System (INIS)

Ji Changsong; Zhang Enshan; Yang Jianfeng; Zhang Hong; Huang Jiling

1995-10-01

It is noted that to design a neutron dose meter of high sensitivity is almost impossible in the frame of traditional designing principle--'absorption net principle'. Based on a newly proposed principle of obtaining neutron dose equi-biological effect adjustment--' absorption stick principle', a brand-new neutron dose-equivalent meter with high neutron sensitivity BH3105 has been developed. Its sensitivity reaches 10 cps/(μSv·h -1 ), which is 18∼40 times higher than one of foreign products of the same kind and is 10 4 times higher than that of domestic FJ342 neutron rem-meter. BH3105 has a measurement range from 0.1μSv/h to 1 Sv/h which is 1 or 2 orders wider than that of the other's. It has the advanced properties of gamma-resistance, energy response, orientation, etc. (6 tabs., 5 figs.)

Monte carlo calculation of energy-dependent response of high-sensitive neutron monitor, HISENS

International Nuclear Information System (INIS)

Imanaka, Tetsuji; Ebisawa, Tohru; Kobayashi, Keiji; Koide, Hiroaki; Seo, Takeshi; Kawano, Shinji

1988-01-01

A highly sensitive neutron monitor system, HISENS, has been developed to measure leakage neutrons from nuclear facilities. The counter system of HISENS contains a detector bank which consists of ten cylindrical proportional counters filled with 10 atm 3 He gas and a paraffin moderator mounted in an aluminum case. The size of the detector bank is 56 cm high, 66 cm wide and 10 cm thick. It is revealed by a calibration experiment using an 241 Am-Be neutron source that the sensitivity of HISENS is about 2000 times as large as that of a typical commercial rem-counter. Since HISENS is designed to have a high sensitivity in a wide range of neutron energy, the shape of its energy dependent response curve cannot be matched to that of the dose equivalent conversion factor. To estimate dose equivalent values from neutron counts by HISENS, it is necessary to know the energy and angular characteristics of both HISENS and the neutron field. The area of one side of the detector bank is 3700 cm 2 and the detection efficiency in the constant region of the response curve is about 30 %. Thus, the sensitivity of HISENS for this energy range is 740 cps/(n/cm 2 /sec). This value indicates the extremely high sensitivity of HISENS as compared with exsisting highly sensitive neutron monitors. (Nogami, K.)

CONSTRUCTION OF A DIFFERENTIAL ISOTHERMAL CALORIMETER OF HIGH SENSITIVITY AND LOW COST.

OpenAIRE

Trinca, RB; Perles, CE; Volpe, PLO

2009-01-01

CONSTRUCTION OF A DIFFERENTIAL ISOTHERMAL CALORIMETER OF HIGH SENSITIVITY AND LOW COST The high cost of sensitivity commercial calorimeters may represent an obstacle for many calorimetric research groups. This work describes (fie construction and calibration of a batch differential heat conduction calorimeter with sample cells volumes of about 400 mu L. The calorimeter was built using two small high sensibility square Peltier thermoelectric sensors and the total cost was estimated to be about...

Highly sensitive micromachined capacitive pressure sensor with reduced hysteresis and low parasitic capacitance

DEFF Research Database (Denmark)

Pedersen, Thomas; Fragiacomo, Giulio; Hansen, Ole

2009-01-01

This paper describes the design and fabrication of a capacitive pressure sensor that has a large capacitance signal and a high sensitivity of 76 pF/bar in touch mode operation. Due to the large signal, problems with parasitic capacitances are avoided and hence it is possible to integrate the sensor...... bonding to create vacuum cavities. The exposed part of the sensor is perfectly flat such that it can be coated with corrosion resistant thin films. Hysteresis is an inherent problem in touch mode capacitive pressure sensors and a technique to significantly reduce it is presented....... with a discrete components electronics circuit for signal conditioning. Using an AC bridge electronics circuit a resolution of 8 mV/mbar is achieved. The large signal is obtained due to a novel membrane structure utilizing closely packed hexagonal elements. The sensor is fabricated in a process based on fusion...

FEAST: sensitive local alignment with multiple rates of evolution.

Science.gov (United States)

Hudek, Alexander K; Brown, Daniel G

2011-01-01

We present a pairwise local aligner, FEAST, which uses two new techniques: a sensitive extension algorithm for identifying homologous subsequences, and a descriptive probabilistic alignment model. We also present a new procedure for training alignment parameters and apply it to the human and mouse genomes, producing a better parameter set for these sequences. Our extension algorithm identifies homologous subsequences by considering all evolutionary histories. It has higher maximum sensitivity than Viterbi extensions, and better balances specificity. We model alignments with several submodels, each with unique statistical properties, describing strongly similar and weakly similar regions of homologous DNA. Training parameters using two submodels produces superior alignments, even when we align with only the parameters from the weaker submodel. Our extension algorithm combined with our new parameter set achieves sensitivity 0.59 on synthetic tests. In contrast, LASTZ with default settings achieves sensitivity 0.35 with the same false positive rate. Using the weak submodel as parameters for LASTZ increases its sensitivity to 0.59 with high error. FEAST is available at http://monod.uwaterloo.ca/feast/.

Sensitive method for the determination of rare earth elements by radioisotope-excited XRF employing a high purity germanium detector in optimized geometry

International Nuclear Information System (INIS)

Lal, M.; Joseph, D.; Patra, P.K.; Bajpal, H.N.

1993-01-01

A close-coupled side-source geometrical configuration is proposed for obtaining a high detection sensitivity for rare earth elements (57 ≤ Z ≤ 69) by radioisotope-excited energy-dispersive x-ray fluorescence spectrometry. In this configuration a disc source of 241 Am (100 mCi), a high-purity germanium detector and thin samples of rare earth elements on a Mylar backing are employed in an optimized geometry to achieve detection limits in the range 20-50 ng for these elements in a counting time of 1 h. (author)

A high sensitivity process variation sensor utilizing sub-threshold operation

OpenAIRE

Meterelliyoz, Mesut; Song, Peilin; Stellari, Franco; Kulkarni, Jaydeep P.; Roy, Kaushik

2008-01-01

In this paper, we propose a novel low-power, bias-free, high-sensitivity process variation sensor for monitoring random variations in the threshold voltage. The proposed sensor design utilizes the exponential current-voltage relationship of sub-threshold operation thereby improving the sensitivity by 2.3X compared to the above-threshold operation. A test-chip containing 128 PMOS and 128 NMOS devices has been fabri...

Hmong Parental Involvement and Support: A Comparison Between Families of High and Low Achieving High School Seniors

Directory of Open Access Journals (Sweden)

Katherine Green

2009-01-01

Full Text Available The Hmong are some of the newest refugees who have settled in the United States with population estimates around 300,000. Unfortunately research has shown many Hmong children are not as successful in their education as their peers. Parental involvement in education has consistently been shown to impact academic success and attendance in higher education programs. Little is known about Hmong parental involvement in their children’s education process. Therefore, this study was done to compare and contrast the general family characteristics, parenting methods, parental involvement philosophies, parental involvement experiences, and parental education expectations in Hmong families of high school seniors classified as either high academic achievers or low achievers. Students were classified into either higher or lower academic achievement groups based on their high school cumulative GPA. Five students were randomly selected for each group and a qualitative research interview method was used to interview the students and both of their parents (n=30. The findings showed the parents of the higher academic achieving students were younger, had higher levels of education, and had better relationships and trust with the students. Parents from both groups did not have any written rules for their children to follow at home, they mainly became involved in their children’s education during the elementary and middle school years, and they did not have any specific preference of an educational level, career, or school for their children after high school. Recommendations for ways Hmong families can be encouraged to participate more in education are made.

Co3O4 based non-enzymatic glucose sensor with high sensitivity and reliable stability derived from hollow hierarchical architecture

Science.gov (United States)

Tian, Liangliang; He, Gege; Cai, Yanhua; Wu, Shenping; Su, Yongyao; Yan, Hengqing; Yang, Cong; Chen, Yanling; Li, Lu

2018-02-01

Inspired by kinetics, the design of hollow hierarchical electrocatalysts through large-scale integration of building blocks is recognized as an effective approach to the achievement of superior electrocatalytic performance. In this work, a hollow, hierarchical Co3O4 architecture (Co3O4 HHA) was constructed using a coordinated etching and precipitation (CEP) method followed by calcination. The resulting Co3O4 HHA electrode exhibited excellent electrocatalytic activity in terms of high sensitivity (839.3 μA mM-1 cm-2) and reliable stability in glucose detection. The high sensitivity could be attributed to the large specific surface area (SSA), ample unimpeded penetration diffusion paths and high electron transfer rate originating from the unique two-dimensional (2D) sheet-like character and hollow porous architecture. The hollow hierarchical structure also affords sufficient interspace for accommodation of volume change and structural strain, resulting in enhanced stability. The results indicate that Co3O4 HHA could have potential for application in the design of non-enzymatic glucose sensors, and that the construction of hollow hierarchical architecture provides an efficient way to design highly active, stable electrocatalysts.

Sensitivity to apomorphine-induced yawning and hypothermia in rats eating standard or high-fat chow.

Science.gov (United States)

Baladi, Michelle G; Thomas, Yvonne M; France, Charles P

2012-07-01

Feeding conditions modify sensitivity to indirect- and direct-acting dopamine receptor agonists as well as the development of sensitization to these drugs. This study examined whether feeding condition affects acute sensitivity to apomorphine-induced yawning or changes in sensitivity that occur over repeated drug administration. Quinpirole-induced yawning was also evaluated to see whether sensitization to apomorphine confers cross-sensitization to quinpirole. Drug-induced yawning was measured in different groups of male Sprague Dawley rats (n = 6/group) eating high (34.3%) fat or standard (5.7% fat) chow. Five weeks of eating high-fat chow rendered otherwise drug-naïve rats more sensitive to apomorphine- (0.01-1.0 mg/kg, i.p.) and quinpirole- (0.0032-0.32 mg/kg, i.p.) induced yawning, compared with rats eating standard chow. In other rats, tested weekly with apomorphine, sensitivity to apomorphine-induced yawning increased (sensitization) similarly in rats with free access to standard or high-fat chow; conditioning to the testing environment appeared to contribute to increased yawning in both groups of rats. Food restriction decreased sensitivity to apomorphine-induced yawning across five weekly tests. Rats with free access to standard or high-fat chow and sensitized to apomorphine were cross-sensitized to quinpirole-induced yawning. The hypothermic effects of apomorphine and quinpirole were not different regardless of drug history or feeding condition. Eating high-fat chow or restricting access to food alters sensitivity to direct-acting dopamine receptor agonists (apomorphine, quinpirole), although the relative contribution of drug history and dietary conditions to sensitivity changes appears to vary among agonists.

An UPLC-MS/MS method for highly sensitive high-throughput analysis of phytohormones in plant tissues

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Balcke Gerd Ulrich

2012-11-01

Full Text Available Abstract Background Phytohormones are the key metabolites participating in the regulation of multiple functions of plant organism. Among them, jasmonates, as well as abscisic and salicylic acids are responsible for triggering and modulating plant reactions targeted against pathogens and herbivores, as well as resistance to abiotic stress (drought, UV-irradiation and mechanical wounding. These factors induce dramatic changes in phytohormone biosynthesis and transport leading to rapid local and systemic stress responses. Understanding of underlying mechanisms is of principle interest for scientists working in various areas of plant biology. However, highly sensitive, precise and high-throughput methods for quantification of these phytohormones in small samples of plant tissues are still missing. Results Here we present an LC-MS/MS method for fast and highly sensitive determination of jasmonates, abscisic and salicylic acids. A single-step sample preparation procedure based on mixed-mode solid phase extraction was efficiently combined with essential improvements in mobile phase composition yielding higher efficiency of chromatographic separation and MS-sensitivity. This strategy resulted in dramatic increase in overall sensitivity, allowing successful determination of phytohormones in small (less than 50 mg of fresh weight tissue samples. The method was completely validated in terms of analyte recovery, sensitivity, linearity and precision. Additionally, it was cross-validated with a well-established GC-MS-based procedure and its applicability to a variety of plant species and organs was verified. Conclusion The method can be applied for the analyses of target phytohormones in small tissue samples obtained from any plant species and/or plant part relying on any commercially available (even less sensitive tandem mass spectrometry instrumentation.

Eating high-fat chow enhances sensitization to the effects of methamphetamine on locomotion in rats.

Science.gov (United States)

McGuire, Blaine A; Baladi, Michelle G; France, Charles P

2011-05-11

Eating high-fat chow can modify the effects of drugs acting directly or indirectly on dopamine systems and repeated intermittent drug administration can markedly increase sensitivity (i.e., sensitization) to the behavioral effects of indirect-acting dopamine receptor agonists (e.g., methamphetamine). This study examined whether eating high-fat chow alters the sensitivity of male Sprague Dawley rats to the locomotor stimulating effects of acute or repeated administration of methamphetamine. The acute effects of methamphetamine on locomotion were not different between rats (n=6/group) eating high-fat or standard chow for 1 or 4 weeks. Sensitivity to the effects of methamphetamine (0.1-10mg/kg, i.p.) increased progressively across 4 once per week tests; this sensitization developed more rapidly and to a greater extent in rats eating high-fat chow as compared with rats eating standard chow. Thus, while eating high-fat chow does not appear to alter sensitivity of rats to acutely-administered methamphetamine, it significantly increases the sensitization that develops to repeated intermittent administration of methamphetamine. These data suggest that eating certain foods influences the development of sensitization to drugs acting on dopamine systems. Copyright © 2011 Elsevier B.V. All rights reserved.

High sensitivity amplifier/discriminator for PWC's

International Nuclear Information System (INIS)

Hansen, S.

1983-01-01

The facility support group at Fermilab is designing and building a general purpose beam chamber for use in several locations at the laboratory. This pwc has 128 wires per plane spaced 1 mm apart. An initial production of 25 signal planes is anticipated. In proportional chambers, the size of the signal depends exponentially on the charge stored per unit of length along the anode wire. As the wire spacing decreases, the capacitance per unit length decreases, thereby requiring increased applied voltage to restore the necessary charge per unit length. In practical terms, this phenomenon is responsible for difficulties in constructing chambers with less than 2 mm wire spacing. 1 mm chambers, therefore, are frequently operated very near to their breakdown point and/or a high gain gas containing organic compounds such as magic gas is used. This argon/iso-butane mixture has three drawbacks: it is explosive when exposed to the air, it leaves a residue on the wires after extended use and is costly. An amplifier with higher sensitivity would reduce the problems associated with operating chambers with small wire spacings and allow them to be run a safe margin below their breakdown voltage even with an inorganic gas mixture such as argon/CO2, this eliminating the need to use magic gas. Described here is a low cost amplifier with a usable threshold of less than 0.5 μA. Data on the performance of this amplifier/discriminator in operation on a prototype beam chamber are given. This data shows the advantages of the high sensitivity of this design

A highly sensitive and specific assay for vertebrate collagenase

International Nuclear Information System (INIS)

Sodek, J.; Hurum, S.; Feng, J.

1981-01-01

A highly sensitive and specific assay for vertebrate collagenase has been developed using a [ 14 C]-labeled collagen substrate and a combination of SDS-PAGE (sodium dodecyl sulfate-polyacrylamide gel electrophoresis) and fluorography to identify and quantitate the digestion products. The assay was sufficiently sensitive to permit the detection and quantitation of collagenase activity in 0.1 μl of gingival sulcal fluid, and in samples of cell culture medium without prior concentration. The assay has also been used to detect the presence of inhibitors of collagenolytic enzymes in various cell culture fluids. (author)

Association of Pattern of Bacteria Sensitivity During the Empirical Antibiotics Use to the Achievement of Clinical Outcome in Pediatric Patients with Pneumonia

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Vesara A. Gatera

2014-12-01

Full Text Available Pneumonia is one of infectious diseases that require a comprehensive and effective effort in its treatment, including in the use of empirical antibiotics. The use of empirical antibiotics should be based on patterns of sensitivity toward bacteria. The aim of this study was to evaluate the use of antibiotics based on the sensitivity patterns by clinical outcomes as the goal of treatment. This study was conducted in Hasan Sadikin Hospital Bandung in October–December 2013 using a retrospective cross-sectional study design. Secondary data were obtained from medical records during January 2011–December 2012. This study consisted of 24 patients with positive culture test and received antibiotic prescription. The results showed the percentage of the use of cefotaxime-ampicillin (37.5%, cefotaxime (33.3%, ceftriaxone (20.8%, and Ampicillin (8.4%. The most influential antibiotics for achieving clinical outcome using 95% confidence level is combination of cefotaxime-ampiciline (P=0.044 with 77.7% sensitivity level. This study suggested that the pattern of antibiotic sensitivity affected the clinical outcomes of pediatric patients with pneumonia.

Resting serum concentration of high-sensitivity C-reactive protein ...

African Journals Online (AJOL)

Resting serum concentration of high-sensitivity C-reactive protein (hs-CRP) in sportsmen and untrained male adults. F.A. Niyi-Odumosu, O. A. Bello, S.A. Biliaminu, B.V. Owoyele, T.O. Abu, O.L. Dominic ...

Does High School Facility Quality Affect Student Achievement? A Two-Level Hierarchical Linear Model

Science.gov (United States)

Bowers, Alex J.; Urick, Angela

2011-01-01

The purpose of this study is to isolate the independent effects of high school facility quality on student achievement using a large, nationally representative U.S. database of student achievement and school facility quality. Prior research on linking school facility quality to student achievement has been mixed. Studies that relate overall…

ZnO nanorod biosensor for highly sensitive detection of specific protein binding

International Nuclear Information System (INIS)

Kim, Jin Suk; Park, Won Il; Lee, Chul Ho; Yi, Gyu Chul

2006-01-01

We report on the fabrication of electrical biosensors based on functionalized ZnO nanorod surfaces with biotin for highly sensitive detection of biological molecules. Due to the clean interface and easy surface modification, the ZnO nanorod sensors can easily detect streptavidin binding down to a concentration of 25 nM, which is more sensitive than previously reported one-dimensional (1D) nanostructure electrical biosensors. In addition, the unique device structure with a micrometer-scale hole at the center of the ZnO nanorod's conducting channel reduces the leakage current from the aqueous solution, hence enhancing device sensitivity. Moreover, ZnO nanorod field-effect-transistor (FET) sensors may open up opportunities to create many other oxide nanorod electrical sensors for highly sensitive and selective real-time detection of a wide variety of biomolecules.

High Throughput Measurement of Locomotor Sensitization to Volatilized Cocaine in Drosophila melanogaster.

Science.gov (United States)

Filošević, Ana; Al-Samarai, Sabina; Andretić Waldowski, Rozi

2018-01-01

Drosophila melanogaster can be used to identify genes with novel functional roles in neuronal plasticity induced by repeated consumption of addictive drugs. Behavioral sensitization is a relatively simple behavioral output of plastic changes that occur in the brain after repeated exposures to drugs of abuse. The development of screening procedures for genes that control behavioral sensitization has stalled due to a lack of high-throughput behavioral tests that can be used in genetically tractable organism, such as Drosophila . We have developed a new behavioral test, FlyBong, which combines delivery of volatilized cocaine (vCOC) to individually housed flies with objective quantification of their locomotor activity. There are two main advantages of FlyBong: it is high-throughput and it allows for comparisons of locomotor activity of individual flies before and after single or multiple exposures. At the population level, exposure to vCOC leads to transient and concentration-dependent increase in locomotor activity, representing sensitivity to an acute dose. A second exposure leads to further increase in locomotion, representing locomotor sensitization. We validate FlyBong by showing that locomotor sensitization at either the population or individual level is absent in the mutants for circadian genes period (per) , Clock (Clk) , and cycle (cyc) . The locomotor sensitization that is present in timeless (tim) and pigment dispersing factor (pdf) mutant flies is in large part not cocaine specific, but derived from increased sensitivity to warm air. Circadian genes are not only integral part of the neural mechanism that is required for development of locomotor sensitization, but in addition, they modulate the intensity of locomotor sensitization as a function of the time of day. Motor-activating effects of cocaine are sexually dimorphic and require a functional dopaminergic transporter. FlyBong is a new and improved method for inducing and measuring locomotor sensitization

High Throughput Measurement of Locomotor Sensitization to Volatilized Cocaine in Drosophila melanogaster

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Ana Filošević

2018-02-01

Full Text Available Drosophila melanogaster can be used to identify genes with novel functional roles in neuronal plasticity induced by repeated consumption of addictive drugs. Behavioral sensitization is a relatively simple behavioral output of plastic changes that occur in the brain after repeated exposures to drugs of abuse. The development of screening procedures for genes that control behavioral sensitization has stalled due to a lack of high-throughput behavioral tests that can be used in genetically tractable organism, such as Drosophila. We have developed a new behavioral test, FlyBong, which combines delivery of volatilized cocaine (vCOC to individually housed flies with objective quantification of their locomotor activity. There are two main advantages of FlyBong: it is high-throughput and it allows for comparisons of locomotor activity of individual flies before and after single or multiple exposures. At the population level, exposure to vCOC leads to transient and concentration-dependent increase in locomotor activity, representing sensitivity to an acute dose. A second exposure leads to further increase in locomotion, representing locomotor sensitization. We validate FlyBong by showing that locomotor sensitization at either the population or individual level is absent in the mutants for circadian genes period (per, Clock (Clk, and cycle (cyc. The locomotor sensitization that is present in timeless (tim and pigment dispersing factor (pdf mutant flies is in large part not cocaine specific, but derived from increased sensitivity to warm air. Circadian genes are not only integral part of the neural mechanism that is required for development of locomotor sensitization, but in addition, they modulate the intensity of locomotor sensitization as a function of the time of day. Motor-activating effects of cocaine are sexually dimorphic and require a functional dopaminergic transporter. FlyBong is a new and improved method for inducing and measuring locomotor

The Effect of a Diet Moderately High in Protein and Fiber on Insulin Sensitivity Measured Using the Dynamic Insulin Sensitivity and Secretion Test (DISST

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Lisa Te Morenga

2017-11-01

Full Text Available Evidence shows that weight loss improves insulin sensitivity but few studies have examined the effect of macronutrient composition independently of weight loss on direct measures of insulin sensitivity. We randomised 89 overweight or obese women to either a standard diet (StdD, that was intended to be low in fat and relatively high in carbohydrate (n = 42 or to a relatively high protein (up to 30% of energy, relatively high fibre (>30 g/day diet (HPHFib (n = 47 for 10 weeks. Advice regarding strict adherence to energy intake goals was not given. Insulin sensitivity and secretion was assessed by a novel method—the Dynamic Insulin Sensitivity and Secretion Test (DISST. Although there were significant improvements in body composition and most cardiometabolic risk factors on HPHFib, insulin sensitivity was reduced by 19.3% (95% CI: 31.8%, 4.5%; p = 0.013 in comparison with StdD. We conclude that the reduction in insulin sensitivity after a diet relatively high in both protein and fibre, despite cardiometabolic improvements, suggests insulin sensitivity may reflect metabolic adaptations to dietary composition for maintenance of glucose homeostasis, rather than impaired metabolism.

High Sensitivity TSS Prediction: Estimates of Locations Where TSS Cannot Occur

KAUST Repository

Schaefer, Ulf; Kodzius, Rimantas; Kai, Chikatoshi; Kawai, Jun; Carninci, Piero; Hayashizaki, Yoshihide; Bajic, Vladimir B.

2013-01-01

from mouse and human genomes, we developed a methodology that allows us, by performing computational TSS prediction with very high sensitivity, to annotate, with a high accuracy in a strand specific manner, locations of mammalian genomes that are highly

Highly Sensitive Reentrant Cavity-Microstrip Patch Antenna Integrated Wireless Passive Pressure Sensor for High Temperature Applications

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Fei Lu

2017-01-01

Full Text Available A novel reentrant cavity-microstrip patch antenna integrated wireless passive pressure sensor was proposed in this paper for high temperature applications. The reentrant cavity was analyzed from aspects of distributed model and equivalent lumped circuit model, on the basis of which an optimal sensor structure integrated with a rectangular microstrip patch antenna was proposed to better transmit/receive wireless signals. In this paper, the proposed sensor was fabricated with high temperature resistant alumina ceramic and silver metalization with weld sealing, and it was measured in a hermetic metal tank with nitrogen pressure loading. It was verified that the sensor was highly sensitive, keeping stable performance up to 300 kPa with an average sensitivity of 981.8 kHz/kPa at temperature 25°C, while, for high temperature measurement, the sensor can operate properly under pressure of 60–120 kPa in the temperature range of 25–300°C with maximum pressure sensitivity of 179.2 kHz/kPa. In practical application, the proposed sensor is used in a method called table lookup with a maximum error of 5.78%.

High-throughput, Highly Sensitive Analyses of Bacterial Morphogenesis Using Ultra Performance Liquid Chromatography*

Science.gov (United States)

Desmarais, Samantha M.; Tropini, Carolina; Miguel, Amanda; Cava, Felipe; Monds, Russell D.; de Pedro, Miguel A.; Huang, Kerwyn Casey

2015-01-01

The bacterial cell wall is a network of glycan strands cross-linked by short peptides (peptidoglycan); it is responsible for the mechanical integrity of the cell and shape determination. Liquid chromatography can be used to measure the abundance of the muropeptide subunits composing the cell wall. Characteristics such as the degree of cross-linking and average glycan strand length are known to vary across species. However, a systematic comparison among strains of a given species has yet to be undertaken, making it difficult to assess the origins of variability in peptidoglycan composition. We present a protocol for muropeptide analysis using ultra performance liquid chromatography (UPLC) and demonstrate that UPLC achieves resolution comparable with that of HPLC while requiring orders of magnitude less injection volume and a fraction of the elution time. We also developed a software platform to automate the identification and quantification of chromatographic peaks, which we demonstrate has improved accuracy relative to other software. This combined experimental and computational methodology revealed that peptidoglycan composition was approximately maintained across strains from three Gram-negative species despite taxonomical and morphological differences. Peptidoglycan composition and density were maintained after we systematically altered cell size in Escherichia coli using the antibiotic A22, indicating that cell shape is largely decoupled from the biochemistry of peptidoglycan synthesis. High-throughput, sensitive UPLC combined with our automated software for chromatographic analysis will accelerate the discovery of peptidoglycan composition and the molecular mechanisms of cell wall structure determination. PMID:26468288

Sensitivity to contamination of optical coatings

International Nuclear Information System (INIS)

Macleod, A.

1999-01-01

A simple theory is presented of the sensitivity to contamination of optical coatings, which permits prediction of performance degradation in the presence of small deposit s of absorbing material. Although a major objective is the ability to compare the sensitivities of different coating types, absolute values can be made possible by adopting a standard contamination layer consisting of a 1 Angstrom thickness of carbon. Results are quoted for a number of common thin-film coatings and filters and are sometimes surprising. The common high-reflectance coating is the quarterwave stack and, at its reference wavelength, it has very low sensitivity to contamination. Although minor constructional errors have little effect on the reflectance, they can seriously affect the contamination sensitivity. Further, the level of contamination determines the maximum reflectance it is possible to achieve, regardless of the number of layers in the coating. The admittance diagram helps in understanding the reasons for the very large variations in sensitivity between coatings with quite similar reflectance

Highly sensitive electrochemical detection of methyl salicylate using electroactive gold nanoparticles.

Science.gov (United States)

Umasankar, Yogeswaran; Ramasamy, Ramaraja P

2013-11-07

Electrochemical sensing of methyl salicylate, a key plant volatile has been achieved using a gold nanoparticle (AuNP) modified screen printed carbon electrode (SPCE). The electrochemical response of planar gold electrodes, SPCE and AuNP-SPCE in alkaline electrolyte in the presence and absence of methyl salicylate were studied to understand the amperometric response of various electrochemical reactions. The reaction mechanism includes hydrolysis of methyl salicylate and the oxidation of negative species. The electrochemical responses were recorded using cyclic voltammetry and differential pulse voltammetry techniques, where the results showed characteristic signals for methyl salicylate oxidation. Among the examined electrodes, AuNP-SPCE possessed three fold better sensitivity than planar gold and 35 times better sensitivity than SPCE (at 0.5 V). The methyl salicylate sensing by AuNP-SPCE possessed 95% of its methyl salicylate response. The electroanalytical results of soybean extract showed that AuNP-SPCE can be employed for the determination of methyl salicylate in real samples.

Islamic Senior High School Students’ Language Learning Strategies and their English Achievement

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ISTI QOMARIAH

2018-05-01

Full Text Available This study investigated the correlation between language learning strategies and English achievement, and explored the influence of language learning strategies on English achievement of eleventh grade students’ of MAN 3 Palembang. A total of 141 eleventh grade students participated in this study. The questionnaire and test were used to collect the data. For this purpose, the language learning strategies (SILL questionnaire developed by Oxford (1989 measured language learning strategies and TOEFL junior (2015 was used to know students’ English achievement. There were three levels from high to low based on the results of SILL questionnaire and five categories English achievement test. Descriptive stastistic, pearson product moment correlation and regression anlaysis were employed to analyze the data. Based on the data analysis, it was found that r (.665 > rtable (.165 with significant level which was lower than 0.05. Thus, it indicated that there was significant correlation between language learning strategies and English achievement. It was implied that good language learners caused good in English achievement.

Sensitivities in synchrotron radiation TXRF

International Nuclear Information System (INIS)

Pianetta, P.; Baur, K.; Brennan, S.

2000-01-01

This work describes the progress we achieved at the Stanford Synchrotron Radiation Laboratory (SSRL) in improving the sensitivity for both the transition metals and light elements such as Al and Na. The transition metal work has matured to the point where a facility exists at SSRL in which semiconductor companies are able to perform industrially relevant measurements at state of the art detection limits. This facility features clean wafer handling and automated data acquisition making routine analytical measurements possible. The best sensitivity demonstrated so far is 3.4 E7 atoms/cm 2 for a 5000 second count time corresponding to 7.6 E7 atoms/cm 2 for a standard 1000 second count time. This is more than a factor of 100 better than what can be achieved with conventional TXRF systems. The detection of light elements such as Al and Na is challenging due to the presence of the h stronger Si fluorescence peak. For traditional energy-dispersive detection only the tunability of synchrotron radiation to excitation energies below the Si-K absorption edge leads to an acceptable sensitivity for Al detection which is limited by a large background due to inelastic x-ray Raman scattering. An alternative approach to overcome the Raman contribution and the strong Si fluorescence is to use a wavelength-dispersive spectrometer for fluorescence detection. The benefits of such a multilayer spectrometer over a solid state detector are its higher energy resolution and greater dynamic range. This strategy allows primary excitation above the Si K absorption edge, eliminating the background due to Raman scattering, and a gracing emission geometry to guarantee high surface sensitivity. Studies testing this concept in combination with high flux synchrotron radiation are underway and first results will be presented. (author)

High sensitivity troponin and valvular heart disease.

Science.gov (United States)

McCarthy, Cian P; Donnellan, Eoin; Phelan, Dermot; Griffin, Brian P; Enriquez-Sarano, Maurice; McEvoy, John W

2017-07-01

Blood-based biomarkers have been extensively studied in a range of cardiovascular diseases and have established utility in routine clinical care, most notably in the diagnosis of acute coronary syndrome (e.g., troponin) and the management of heart failure (e.g., brain-natriuretic peptide). The role of biomarkers is less well established in the management of valvular heart disease (VHD), in which the optimal timing of surgical intervention is often challenging. One promising biomarker that has been the subject of a number of recent VHD research studies is high sensitivity troponin (hs-cTn). Novel high-sensitivity assays can detect subclinical myocardial damage in asymptomatic individuals. Thus, hs-cTn may have utility in the assessment of asymptomatic patients with severe VHD who do not have a clear traditional indication for surgical intervention. In this state-of-the-art review, we examine the current evidence for hs-cTn as a potential biomarker in the most commonly encountered VHD conditions, aortic stenosis and mitral regurgitation. This review provides a synopsis of early evidence indicating that hs-cTn has promise as a biomarker in VHD. However, the impact of its measurement on clinical practice and VHD outcomes needs to be further assessed in prospective studies before routine clinical use becomes a reality. Copyright © 2017 Elsevier Inc. All rights reserved.

Organic dye for highly efficient solid-state dye-sensitized solar cells

Energy Technology Data Exchange (ETDEWEB)

Schmidt-Mende, L.; Bach, U.; Humphry-Baker, R.; Ito, S.; Graetzel, M. [Institut des Sciences et Ingenierie Chimiques (ISIC), Laboratoire de Photonique et Interfaces (LPI), Ecole Polytechnique Federale de Lausanne (EPFL), CH-1015 Lausanne (Switzerland); Horiuchi, T.; Miura, H. [Technology Research Laboratory, Corporate Research Center, Mitsubishi Paper Mills Limited, 46, Wadai, Tsukuba City, Ibaraki 300-4247 (Japan); Uchida, S. [Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, 1-1 Katahira 2-chome, Aoba-ku, Sendai 980-8577 (Japan)

2005-04-04

The feasibility of solid-state dye-sensitized solar cells as a low-cost alternative to amorphous silicon cells is demonstrated. Such a cell with a record efficiency of over 4 % under simulated sunlight is reported, made possible by using a new organic metal-free indoline dye as the sensitizer with high absorption coefficient. (Abstract Copyright [2005], Wiley Periodicals, Inc.)

Immobilization of Ni-Pd/core-shell nanoparticles through thermal polymerization of acrylamide on glassy carbon electrode for highly stable and sensitive glutamate detection.

Science.gov (United States)

Yu, Huicheng; Ma, Zhenzhen; Wu, Zhaoyang

2015-10-08

The preparation of a persistently stable and sensitive biosensor is highly important for practical applications. To improve the stability and sensitivity of glutamate sensors, an electrode modified with glutamate dehydrogenase (GDH)/Ni-Pd/core-shell nanoparticles was developed using the thermal polymerization of acrylamide (AM) to immobilize the synthesized Ni-Pd/core-shell nanoparticles onto a glassy carbon electrode (GCE). The modified electrode was characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). Electrochemical data showed that the prepared biosensor had remarkably enhanced electrocatalytic activity toward glutamate. Moreover, superior reproducibility and excellent stability were observed (relative average deviation was 2.96% after continuous use of the same sensor for 60 times, and current responses remained at 94.85% of the initial value after 60 d). The sensor also demonstrated highly sensitive amperometric detection of glutamate with a low limit of detection (0.052 μM, S/N = 3), high sensitivity (4.768 μA μM(-1) cm(-2)), and a wide, useful linear range (0.1-500 μM). No interference from potential interfering species such as l-cysteine, ascorbic acid, and l-aspartate were noted. The determination of glutamate levels in actual samples achieved good recovery percentages. Copyright © 2015 Elsevier B.V. All rights reserved.

Differential sensitivity of long-sleep and short-sleep mice to high doses of cocaine.

Science.gov (United States)

de Fiebre, C M; Ruth, J A; Collins, A C

1989-12-01

The cocaine sensitivity of male and female long-sleep (LS) and short-sleep (SS) mice, which have been selectively bred for differential ethanol-induced "sleep-time," was examined in a battery of behavioral and physiological tests. Differences between these two mouse lines were subtle and were seen primarily at high doses. At high doses, SS mice were more sensitive than LS mice, particularly to cocaine-induced hypothermia; however, significant hypothermia was not seen except at doses which were very near to the seizure threshold. During a 60-min test of locomotor activity, LS mice showed greater stimulation of Y-maze activity by 20 mg/kg cocaine than SS mice. Consistent with the finding of subtle differences in sensitivity to low doses of cocaine. LS and SS mice did not differ in sensitivity to cocaine inhibition of synaptosomal uptake of [3H]-dopamine, [3H]-norepinephrine or [3H]-5-hydroxytryptamine. However, consistent with the finding of differential sensitivity to high doses of cocaine, SS mice were more sensitive to the seizure-producing effects of the cocaine and lidocaine, a local anesthetic. It is hypothesized that the differential sensitivity of these mouse lines to high doses of cocaine is due to differential sensitivity to cocaine's actions on systems that regulate local anesthetic effects. Selective breeding for differential duration of alcohol-induced "sleep-time" may have resulted in differential ion channel structure or function in these mice.

Sensitivity analysis for improving nanomechanical photonic transducers biosensors

International Nuclear Information System (INIS)

Fariña, D; Álvarez, M; Márquez, S; Lechuga, L M; Dominguez, C

2015-01-01

The achievement of high sensitivity and highly integrated transducers is one of the main challenges in the development of high-throughput biosensors. The aim of this study is to improve the final sensitivity of an opto-mechanical device to be used as a reliable biosensor. We report the analysis of the mechanical and optical properties of optical waveguide microcantilever transducers, and their dependency on device design and dimensions. The selected layout (geometry) based on two butt-coupled misaligned waveguides displays better sensitivities than an aligned one. With this configuration, we find that an optimal microcantilever thickness range between 150 nm and 400 nm would increase both microcantilever bending during the biorecognition process and increase optical sensitivity to 4.8   ×   10 −2  nm −1 , an order of magnitude higher than other similar opto-mechanical devices. Moreover, the analysis shows that a single mode behaviour of the propagating radiation is required to avoid modal interference that could misinterpret the readout signal. (paper)

Characterization of a high resolution and high sensitivity pre-clinical PET scanner with 3D event reconstruction

CERN Document Server

Rissi, M; Bolle, E; Dorholt, O; Hines, K E; Rohne, O; Skretting, A; Stapnes, S; Volgyes, D

2012-01-01

COMPET is a preclinical PET scanner aiming towards a high sensitivity, a high resolution and MRI compatibility by implementing a novel detector geometry. In this approach, long scintillating LYSO crystals are used to absorb the gamma-rays. To determine the point of interaction (P01) between gamma-ray and crystal, the light exiting the crystals on one of the long sides is collected with wavelength shifters (WLS) perpendicularly arranged to the crystals. This concept has two main advantages: (1) The parallax error is reduced to a minimum and is equal for the whole field of view (FOV). (2) The P01 and its energy deposit is known in all three dimension with a high resolution, allowing for the reconstruction of Compton scattered gamma-rays. Point (1) leads to a uniform point source resolution (PSR) distribution over the whole FOV, and also allows to place the detector close to the object being imaged. Both points (1) and (2) lead to an increased sensitivity and allow for both high resolution and sensitivity at the...

The Relationship between Ethical Sensitivity, High Ability and Gender in Higher Education Students

Science.gov (United States)

Schutte, Ingrid; Wolfensberger, Marca; Tirri, Kirsi

2014-01-01

This study examined the ethical sensitivity of high-ability undergraduate students (n=731) in the Netherlands who completed the 28-item Ethical Sensitivity Scale Questionnaire (ESSQ) developed by Tirri & Nokelainen (2007; 2011). The ESSQ is based on Narvaez' (2001) operationalization of ethical sensitivity in seven dimensions. The following…

Design and synthesis of new fluorescent probe for rapid and highly sensitive detection of proteins via electrophoretic gel stain.

Science.gov (United States)

Suzuki, Yoshio; Takagi, Nobuyuki; Chimuro, Tomoyuki; Shinohara, Atsushi; Sakaguchi, Nao; Hiratsuka, Atsunori; Yokoyama, Kenji

2011-06-01

A new fluorescent molecular probe, 2,2'-(1E,1'E)-2,2'-(4-(dicyanomethylene)-4H-pyrane-2,6-diyl)bis(ethene-2,1-diyl)bis(sodium benzenesulfonate) salt (1), possessing the cyanopyranyl moieties and two benzene sulfonic acid groups was designed and synthesized to detect proteins in solution and for high-throughput SDS-PAGE. Compound 1 exhibited no fluorescence in the absence of proteins; however, it exhibited strong fluorescence on the addition of bovine serum albumin as a result of intramolecular charge transfer. Compared with the conventional protocols for in-gel protein staining, such as SYPRO Ruby and silver staining, 1 achieves higher sensitivity, even though it offers a simplified, higher throughput protocol. In fact, the total time required for protein staining was 60-90 min under optimum conditions much shorter than that required by the less-sensitive silver staining or SYPRO Ruby staining protocols. Moreover, 1 was successfully applied to protein identification by mass spectrometry via in-gel tryptic digestion, Western blotting, and native PAGE together with protein staining by 1, which is a modified protocol of blue native PAGE (BN-PAGE). Thus, 1 may facilitate high-sensitivity protein detection, and it may be widely applicable as a convenient tool in various scientific and medical fields. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Low and High Mathematics Achievement in Japanese, Chinese, and American Elementary-School Children.

Science.gov (United States)

Uttal, David H.; And Others

1988-01-01

First and fifth grade students who scored high or low on a mathematics test were tested for intellectual ability and reading achievement. Students and their mothers were interviewed. Results indicated that factors associated with levels of achievement in mathematics operate in a similar fashion across three cultures that differ greatly in their…

Development of the "Highly Sensitive Dog" questionnaire to evaluate the personality dimension "Sensory Processing Sensitivity" in dogs.

Directory of Open Access Journals (Sweden)

Maya Braem

Full Text Available In humans, the personality dimension 'sensory processing sensitivity (SPS', also referred to as "high sensitivity", involves deeper processing of sensory information, which can be associated with physiological and behavioral overarousal. However, it has not been studied up to now whether this dimension also exists in other species. SPS can influence how people perceive the environment and how this affects them, thus a similar dimension in animals would be highly relevant with respect to animal welfare. We therefore explored whether SPS translates to dogs, one of the primary model species in personality research. A 32-item questionnaire to assess the "highly sensitive dog score" (HSD-s was developed based on the "highly sensitive person" (HSP questionnaire. A large-scale, international online survey was conducted, including the HSD questionnaire, as well as questions on fearfulness, neuroticism, "demographic" (e.g. dog sex, age, weight; age at adoption, etc. and "human" factors (e.g. owner age, sex, profession, communication style, etc., and the HSP questionnaire. Data were analyzed using linear mixed effect models with forward stepwise selection to test prediction of HSD-s by the above-mentioned factors, with country of residence and dog breed treated as random effects. A total of 3647 questionnaires were fully completed. HSD-, fearfulness, neuroticism and HSP-scores showed good internal consistencies, and HSD-s only moderately correlated with fearfulness and neuroticism scores, paralleling previous findings in humans. Intra- (N = 447 and inter-rater (N = 120 reliabilities were good. Demographic and human factors, including HSP score, explained only a small amount of the variance of HSD-s. A PCA analysis identified three subtraits of SPS, comparable to human findings. Overall, the measured personality dimension in dogs showed good internal consistency, partial independence from fearfulness and neuroticism, and good intra- and inter

High-sensitivity Raman spectrometer to study pristine and irradiated interstellar ice analogs.

Science.gov (United States)

Bennett, Chris J; Brotton, Stephen J; Jones, Brant M; Misra, Anupam K; Sharma, Shiv K; Kaiser, Ralf I

2013-06-18

We discuss the novel design of a sensitive, normal-Raman spectrometer interfaced to an ultra-high vacuum chamber (5 × 10(-11) Torr) utilized to investigate the interaction of ionizing radiation with low temperature ices relevant to the solar system and interstellar medium. The design is based on a pulsed Nd:YAG laser which takes advantage of gating techniques to isolate the scattered Raman signal from the competing fluorescence signal. The setup incorporates innovations to achieve maximum sensitivity without detectable heating of the sample. Thin films of carbon dioxide (CO2) ices of 10 to 396 nm thickness were prepared and characterized using both Fourier transform infrared (FT-IR) spectroscopy and HeNe interference techniques. The ν+ and ν- Fermi resonance bands of CO2 ices were observed by Raman spectroscopy at 1385 and 1278 cm(-1), respectively, and the band areas showed a linear dependence on ice thickness. Preliminary irradiation experiments are conducted on a 450 nm thick sample of CO2 ice using energetic electrons. Both carbon monoxide (CO) and the infrared inactive molecular oxygen (O2) products are readily detected from their characteristic Raman bands at 2145 and 1545 cm(-1), respectively. Detection limits of 4 ± 3 and 6 ± 4 monolayers of CO and O2 were derived, demonstrating the unique power to detect newly formed molecules in irradiated ices in situ. The setup is universally applicable to the detection of low-abundance species, since no Raman signal enhancement is required, demonstrating Raman spectroscopy as a reliable alternative, or complement, to FT-IR spectroscopy in space science applications.

High-sensitivity bend angle measurements using optical fiber gratings.

Science.gov (United States)

Rauf, Abdul; Zhao, Jianlin; Jiang, Biqiang

2013-07-20

We present a high-sensitivity and more flexible bend measurement method, which is based on the coupling of core mode to the cladding modes at the bending region in concatenation with optical fiber grating serving as band reflector. The characteristics of a bend sensing arm composed of bending region and optical fiber grating is examined for different configurations including single fiber Bragg grating (FBG), chirped FBG (CFBG), and double FBGs. The bend loss curves for coated, stripped, and etched sections of fiber in the bending region with FBG, CFBG, and double FBG are obtained experimentally. The effect of separation between bending region and optical fiber grating on loss is measured. The loss responses for single FBG and CFBG configurations are compared to discover the effectiveness for practical applications. It is demonstrated that the sensitivity of the double FBG scheme is twice that of the single FBG and CFBG configurations, and hence acts as sensitivity multiplier. The bend loss response for different fiber diameters obtained through etching in 40% hydrofluoric acid, is measured in double FBG scheme that resulted in a significant increase in the sensitivity, and reduction of dead-zone.

High Temperature and High Sensitive NOx Gas Sensor with Hetero-Junction Structure using Laser Ablation Method

Science.gov (United States)

Gao, Wei; Shi, Liqin; Hasegawa, Yuki; Katsube, Teruaki

In order to develop a high temperature (200°C˜400°C) and high sensitive NOx gas sensor, we developed a new structure of SiC-based hetero-junction device Pt/SnO2/SiC/Ni, Pt/In2O3/SiC/Ni and Pt/WO3/SiC/Ni using a laser ablation method for the preparation of both metal (Pt) electrode and metal-oxide film. It was found that Pt/In2O3/SiC/Ni sensor shows higher sensitivity to NO2 gas compared with the Pt/SnO2/SiC/Ni and Pt/WO3/SiC/Ni sensor, whereas the Pt/WO3/SiC/Ni sensor had better sensitivity to NO gas. These results suggest that selective detection of NO and NO2 gases may be obtained by choosing different metal oxide films.

1-(3-aminopropyl)-3-butylimidazolium bromide for carboxyl group derivatization: potential applications in high sensitivity peptide identification by mass spectrometry.

Science.gov (United States)

Qiao, Xiaoqiang; Zhou, Yuan; Hou, Chunyan; Zhang, Xiaodan; Yang, Kaiguang; Zhang, Lihua; Zhang, Yukui

2013-03-01

The cationic reagent 1-(3-aminopropyl)-3-butylimidazolium bromide (BAPI) was exploited for the derivatization of carboxyl groups on peptides. Nearly 100% derivatization efficiency was achieved with the synthetic peptide RVYVHPI (RI-7). Furthermore, the peptide derivative was stable in a 0.1% TFA/water solution or a 0.1% (v/v) TFA/acetonitrile/water solution for at least one week. The effect of BAPI derivatization on the ionization of the peptide RI-7 was further investigated, and the detection sensitivity was improved >42-fold via matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), thus outperforming the commercial piperazine derivatization approach. Moreover, the charge states of the peptide were largely increased via BAPI derivatization by electrospray ionization (ESI) MS. The results indicate the potential merits of BAPI derivatization for high sensitivity peptide analysis by MS.

High pressure-sensitive gene expression in Lactobacillus sanfranciscensis

Directory of Open Access Journals (Sweden)

R.F. Vogel

2005-08-01

Full Text Available Lactobacillus sanfranciscensis is a Gram-positive lactic acid bacterium used in food biotechnology. It is necessary to investigate many aspects of a model organism to elucidate mechanisms of stress response, to facilitate preparation, application and performance in food fermentation, to understand mechanisms of inactivation, and to identify novel tools for high pressure biotechnology. To investigate the mechanisms of the complex bacterial response to high pressure we have analyzed changes in the proteome and transcriptome by 2-D electrophoresis, and by microarrays and real time PCR, respectively. More than 16 proteins were found to be differentially expressed upon high pressure stress and were compared to those sensitive to other stresses. Except for one apparently high pressure-specific stress protein, no pressure-specific stress proteins were found, and the proteome response to pressure was found to differ from that induced by other stresses. Selected pressure-sensitive proteins were partially sequenced and their genes were identified by reverse genetics. In a transcriptome analysis of a redundancy cleared shot gun library, about 7% of the genes investigated were found to be affected. Most of them appeared to be up-regulated 2- to 4-fold and these results were confirmed by real time PCR. Gene induction was shown for some genes up-regulated at the proteome level (clpL/groEL/rbsK, while the response of others to high hydrostatic pressure at the transcriptome level seemed to differ from that observed at the proteome level. The up-regulation of selected genes supports the view that the cell tries to compensate for pressure-induced impairment of translation and membrane transport.

Stimulus Sensitivity of a Spiking Neural Network Model

Science.gov (United States)

Chevallier, Julien

2018-02-01

Some recent papers relate the criticality of complex systems to their maximal capacity of information processing. In the present paper, we consider high dimensional point processes, known as age-dependent Hawkes processes, which have been used to model spiking neural networks. Using mean-field approximation, the response of the network to a stimulus is computed and we provide a notion of stimulus sensitivity. It appears that the maximal sensitivity is achieved in the sub-critical regime, yet almost critical for a range of biologically relevant parameters.

A CMOS In-Pixel CTIA High Sensitivity Fluorescence Imager.

Science.gov (United States)

Murari, Kartikeya; Etienne-Cummings, Ralph; Thakor, Nitish; Cauwenberghs, Gert

2011-10-01

Traditionally, charge coupled device (CCD) based image sensors have held sway over the field of biomedical imaging. Complementary metal oxide semiconductor (CMOS) based imagers so far lack sensitivity leading to poor low-light imaging. Certain applications including our work on animal-mountable systems for imaging in awake and unrestrained rodents require the high sensitivity and image quality of CCDs and the low power consumption, flexibility and compactness of CMOS imagers. We present a 132×124 high sensitivity imager array with a 20.1 μm pixel pitch fabricated in a standard 0.5 μ CMOS process. The chip incorporates n-well/p-sub photodiodes, capacitive transimpedance amplifier (CTIA) based in-pixel amplification, pixel scanners and delta differencing circuits. The 5-transistor all-nMOS pixel interfaces with peripheral pMOS transistors for column-parallel CTIA. At 70 fps, the array has a minimum detectable signal of 4 nW/cm(2) at a wavelength of 450 nm while consuming 718 μA from a 3.3 V supply. Peak signal to noise ratio (SNR) was 44 dB at an incident intensity of 1 μW/cm(2). Implementing 4×4 binning allowed the frame rate to be increased to 675 fps. Alternately, sensitivity could be increased to detect about 0.8 nW/cm(2) while maintaining 70 fps. The chip was used to image single cell fluorescence at 28 fps with an average SNR of 32 dB. For comparison, a cooled CCD camera imaged the same cell at 20 fps with an average SNR of 33.2 dB under the same illumination while consuming over a watt.

High order effects in cross section sensitivity analysis

International Nuclear Information System (INIS)

Greenspan, E.; Karni, Y.; Gilai, D.

1978-01-01

Two types of high order effects associated with perturbations in the flux shape are considered: Spectral Fine Structure Effects (SFSE) and non-linearity between changes in performance parameters and data uncertainties. SFSE are investigated in Part I using a simple single resonance model. Results obtained for each of the resolved and for representative unresolved resonances of 238 U in a ZPR-6/7 like environment indicate that SFSE can have a significant contribution to the sensitivity of group constants to resonance parameters. Methods to account for SFSE both for the propagation of uncertainties and for the adjustment of nuclear data are discussed. A Second Order Sensitivity Theory (SOST) is presented, and its accuracy relative to that of the first order sensitivity theory and of the direct substitution method is investigated in Part II. The investigation is done for the non-linear problem of the effect of changes in the 297 keV sodium minimum cross section on the transport of neutrons in a deep-penetration problem. It is found that the SOST provides a satisfactory accuracy for cross section uncertainty analysis. For the same degree of accuracy, the SOST can be significantly more efficient than the direct substitution method

High-Sensitivity Temperature-Independent Silicon Photonic Microfluidic Biosensors

Science.gov (United States)

Kim, Kangbaek

Optical biosensors that can precisely quantify the presence of specific molecular species in real time without the need for labeling have seen increased use in the drug discovery industry and molecular biology in general. Of the many possible optical biosensors, the TM mode Si biosensor is shown to be very attractive in the sensing application because of large field amplitude on the surface and cost effective CMOS VLSI fabrication. Noise is the most fundamental factor that limits the performance of sensors in development of high-sensitivity biosensors, and noise reduction techniques require precise studies and analysis. One such example stems from thermal fluctuations. Generally SOI biosensors are vulnerable to ambient temperature fluctuations because of large thermo-optic coefficient of silicon (˜2x10 -4 RIU/K), typically requiring another reference ring and readout sequence to compensate temperature induced noise. To address this problem, we designed sensors with a novel TM-mode shallow-ridge waveguide that provides both large surface amplitude for bulk and surface sensing. With proper design, this also provides large optical confinement in the aqueous cladding that renders the device athermal using the negative thermo-optic coefficient of water (~ --1x10-4RIU/K), demonstrating cancellation of thermo-optic effects for aqueous solution operation near 300K. Additional limitations resulting from mechanical actuator fluctuations, stability of tunable lasers, and large 1/f noise of lasers and sensor electronics can limit biosensor performance. Here we also present a simple harmonic feedback readout technique that obviates the need for spectrometers and tunable lasers. This feedback technique reduces the impact of 1/f noise to enable high-sensitivity, and a DSP lock-in with 256 kHz sampling rate can provide down to micros time scale monitoring for fast transitions in biomolecular concentration with potential for small volume and low cost. In this dissertation, a novel

"It's a Way of Life for Us": High Mobility and High Achievement in Department of Defense Schools.

Science.gov (United States)

Smrekar, Claire E.; Owens, Debra E.

2003-01-01

Examines the academic performance of students in U.S. Department of Defense Education Activity (DoDEA) schools, which have high student mobility. Some observers contend that these students' high achievement is a function of their middle class family and community characteristics. Asserts that DoDEA schools simultaneously "do the right…

Mo' Money, Mo' Problems? High-Achieving Black High School Students' Experiences with Resources, Racial Climate, and Resilience

Science.gov (United States)

Allen, Walter; Griffin, Kimberly

2006-01-01

A multi-site case study analyzed the college preparatory processes of nine African American high achievers attending a well-resourced, suburban high school and eight academically successful African Americans attending a low-resourced urban school. Students at both schools experienced barriers, that is, racial climate and a lack of resources, that…

Teacher Support, Instructional Practices, Student Motivation, and Mathematics Achievement in High School

Science.gov (United States)

Yu, Rongrong; Singh, Kusum

2018-01-01

The authors examined the relationships among teacher classroom practices, student motivation, and mathematics achievement in high school. The data for this study was drawn from the base-year data of High School Longitudinal Study of 2009. Structural equation modeling method was used to estimate the relationships among variables. The results…

The impact of including children with intellectual disability in general education classrooms on the academic achievement of their low-, average-, and high-achieving peers.

Science.gov (United States)

Sermier Dessemontet, Rachel; Bless, Gérard

2013-03-01

This study aimed at assessing the impact of including children with intellectual disability (ID) in general education classrooms with support on the academic achievement of their low-, average-, and high-achieving peers without disability. A quasi-experimental study was conducted with an experimental group of 202 pupils from classrooms with an included child with mild or moderate ID, and a control group of 202 pupils from classrooms with no included children with special educational needs (matched pairs sample). The progress of these 2 groups in their academic achievement was compared over a period of 1 school year. No significant difference was found in the progress of the low-, average-, or high-achieving pupils from classrooms with or without inclusion. The results suggest that including children with ID in primary general education classrooms with support does not have a negative impact on the progress of pupils without disability.

Instructional, Transformational, and Managerial Leadership and Student Achievement: High School Principals Make a Difference

Science.gov (United States)

Valentine, Jerry W.; Prater, Mike

2011-01-01

This statewide study examined the relationships between principal managerial, instructional, and transformational leadership and student achievement in public high schools. Differences in student achievement were found when schools were grouped according to principal leadership factors. Principal leadership behaviors promoting instructional and…

From Molecular Design to Co-sensitization; High performance indole based photosensitizers for dye-sensitized solar cells

International Nuclear Information System (INIS)

Babu, Dickson D.; Su, Rui; El-Shafei, Ahmed; Adhikari, Airody Vasudeva

2016-01-01

displays promising photovoltaic results and exhibited an enhanced efficiency of 8.06%. Further, good agreement between the calculated and experimental results showcase the precision of the energy functional and basis set utilized in this study. All these findings provide a deeper insight and better understanding into the intricacies involved in the design of superior co-sensitizers for development of highly efficient DSSCs.

A comparison of sorptive extraction techniques coupled to a new quantitative, sensitive, high throughput GC-MS/MS method for methoxypyrazine analysis in wine.

Science.gov (United States)

Hjelmeland, Anna K; Wylie, Philip L; Ebeler, Susan E

2016-02-01

Methoxypyrazines are volatile compounds found in plants, microbes, and insects that have potent vegetal and earthy aromas. With sensory detection thresholds in the low ng L(-1) range, modest concentrations of these compounds can profoundly impact the aroma quality of foods and beverages, and high levels can lead to consumer rejection. The wine industry routinely analyzes the most prevalent methoxypyrazine, 2-isobutyl-3-methoxypyrazine (IBMP), to aid in harvest decisions, since concentrations decrease during berry ripening. In addition to IBMP, three other methoxypyrazines IPMP (2-isopropyl-3-methoxypyrazine), SBMP (2-sec-butyl-3-methoxypyrazine), and EMP (2-ethyl-3-methoxypyrazine) have been identified in grapes and/or wine and can impact aroma quality. Despite their routine analysis in the wine industry (mostly IBMP), accurate methoxypyrazine quantitation is hindered by two major challenges: sensitivity and resolution. With extremely low sensory detection thresholds (~8-15 ng L(-1) in wine for IBMP), highly sensitive analytical methods to quantify methoxypyrazines at trace levels are necessary. Here we were able to achieve resolution of IBMP as well as IPMP, EMP, and SBMP from co-eluting compounds using one-dimensional chromatography coupled to positive chemical ionization tandem mass spectrometry. Three extraction techniques HS-SPME (headspace-solid phase microextraction), SBSE (stirbar sorptive extraction), and HSSE (headspace sorptive extraction) were validated and compared. A 30 min extraction time was used for HS-SPME and SBSE extraction techniques, while 120 min was necessary to achieve sufficient sensitivity for HSSE extractions. All extraction methods have limits of quantitation (LOQ) at or below 1 ng L(-1) for all four methoxypyrazines analyzed, i.e., LOQ's at or below reported sensory detection limits in wine. The method is high throughput, with resolution of all compounds possible with a relatively rapid 27 min GC oven program. Copyright © 2015

Sensitivity optimization of Bell-Bloom magnetometers by manipulation of atomic spin synchronization

Science.gov (United States)

Ranjbaran, M.; Tehranchi, M. M.; Hamidi, S. M.; Khalkhali, S. M. H.

2018-05-01

Many efforts have been devoted to the developments of atomic magnetometers for achieving the high sensitivity required in biomagnetic applications. To reach the high sensitivity, many types of atomic magnetometers have been introduced for optimization of the creation and relaxation rates of atomic spin polarization. In this paper, regards to sensitivity optimization techniques in the Mx configuration, we have proposed a novelty approach for synchronization of the spin precession in the Bell-Bloom magnetometers. We have utilized the phenomenological Bloch equations to simulate the spin dynamics when modulation of pumping light and radio frequency magnetic field were both used for atomic spin synchronization. Our results showed that the synchronization process, improved the magnetometer sensitivity respect to the classical configurations.

Engineered porous silicon counter electrodes for high efficiency dye-sensitized solar cells.

Science.gov (United States)

Erwin, William R; Oakes, Landon; Chatterjee, Shahana; Zarick, Holly F; Pint, Cary L; Bardhan, Rizia

2014-06-25

In this work, we demonstrate for the first time, the use of porous silicon (P-Si) as counter electrodes in dye-sensitized solar cells (DSSCs) with efficiencies (5.38%) comparable to that achieved with platinum counter electrodes (5.80%). To activate the P-Si for triiodide reduction, few layer carbon passivation is utilized to enable electrochemical stability of the silicon surface. Our results suggest porous silicon as a promising sustainable and manufacturable alternative to rare metals for electrochemical solar cells, following appropriate surface modification.

High degree gravitational sensitivity from Mars orbiters for the GMM-1 gravity model

Science.gov (United States)

Lerch, F. J.; Smith, D. E.; Chan, J. C.; Patel, G. B.; Chinn, D. S.

1994-01-01

Orbital sensitivity of the gravity field for high degree terms (greater than 30) is analyzed on satellites employed in a Goddard Mars Model GMM-1, complete in spherical harmonics through degree and order 50. The model is obtained from S-band Doppler data on Mariner 9 (M9), Viking Orbiter 1 (VO1), and Viking Orbiter 2 (VO2) spacecraft, which were tracked by the NASA Deep Space Network on seven different highly eccentric orbits. The main sensitivity of the high degree terms is obtained from the VO1 and VO2 low orbits (300 km periapsis altitude), where significant spectral sensitivity is seen for all degrees out through degree 50. The velocity perturbations show a dominant effect at periapsis and significant effects out beyond the semi-latus rectum covering over 180 degrees of the orbital groundtrack for the low altitude orbits. Because of the wideband of periapsis motion covering nearly 180 degrees in w and +39 degrees in latitude coverage, the VO1 300 km periapsis altitude orbit with inclination of 39 degrees gave the dominant sensitivity in the GMM-1 solution for the high degree terms. Although the VO2 low periapsis orbit has a smaller band of periapsis mapping coverage, it strongly complements the VO1 orbit sensitivity for the GMM-1 solution with Doppler tracking coverage over a different inclination of 80 degrees.

Photon Counting System for High-Sensitivity Detection of Bioluminescence at Optical Fiber End.

Science.gov (United States)

Iinuma, Masataka; Kadoya, Yutaka; Kuroda, Akio

2016-01-01

The technique of photon counting is widely used for various fields and also applicable to a high-sensitivity detection of luminescence. Thanks to recent development of single photon detectors with avalanche photodiodes (APDs), the photon counting system with an optical fiber has become powerful for a detection of bioluminescence at an optical fiber end, because it allows us to fully use the merits of compactness, simple operation, highly quantum efficiency of the APD detectors. This optical fiber-based system also has a possibility of improving the sensitivity to a local detection of Adenosine triphosphate (ATP) by high-sensitivity detection of the bioluminescence. In this chapter, we are introducing a basic concept of the optical fiber-based system and explaining how to construct and use this system.

CALDER: High-sensitivity cryogenic light detectors

International Nuclear Information System (INIS)

Casali, N.; Bellini, F.; Cardani, L.

2017-01-01

The current bolometric experiments searching for rare processes such as neutrinoless double-beta decay or dark matter interaction demand for cryogenic light detectors with high sensitivity, large active area and excellent scalability and radio-purity in order to reduce their background budget. The CALDER project aims to develop such kind of light detectors implementing phonon-mediated Kinetic Inductance Detectors (KIDs). The goal for this project is the realization of a 5 × 5 cm"2 light detector working between 10 and 100mK with a baseline resolution RMS below 20 eV. In this work the characteristics and the performances of the prototype detectors developed in the first project phase will be shown.

Nanostructured dye-sensitized solar cells

OpenAIRE

Palma, Giuseppina

2014-01-01

2012/2013 Dye-sensitized solar cells (DSSCs) represent a promising alternative to silicon-based technology. From the first publications about DSSCs in the 90s, they are considered an important breakthrough for achieving high efficiency by using relatively inexpensive and abundant materials. Stability and efficiency are two crucial points in the development of this new class of hybrid photovoltaic devices. Most of the DSSC studies carried out over the past twenty years are based on the o...

Striving for Excellence Sometimes Hinders High Achievers: Performance-Approach Goals Deplete Arithmetical Performance in Students with High Working Memory Capacity

Science.gov (United States)

Crouzevialle, Marie; Smeding, Annique; Butera, Fabrizio

2015-01-01

We tested whether the goal to attain normative superiority over other students, referred to as performance-approach goals, is particularly distractive for high-Working Memory Capacity (WMC) students—that is, those who are used to being high achievers. Indeed, WMC is positively related to high-order cognitive performance and academic success, a record of success that confers benefits on high-WMC as compared to low-WMC students. We tested whether such benefits may turn out to be a burden under performance-approach goal pursuit. Indeed, for high achievers, aiming to rise above others may represent an opportunity to reaffirm their positive status—a stake susceptible to trigger disruptive outcome concerns that interfere with task processing. Results revealed that with performance-approach goals—as compared to goals with no emphasis on social comparison—the higher the students’ WMC, the lower their performance at a complex arithmetic task (Experiment 1). Crucially, this pattern appeared to be driven by uncertainty regarding the chances to outclass others (Experiment 2). Moreover, an accessibility measure suggested the mediational role played by status-related concerns in the observed disruption of performance. We discuss why high-stake situations can paradoxically lead high-achievers to sub-optimally perform when high-order cognitive performance is at play. PMID:26407097

High-performance thermal sensitive W-doped VO{sub 2}(B) thin film and its identification by first-principles calculations

Energy Technology Data Exchange (ETDEWEB)

Wan, Dongyun; Xiong, Ping; Chen, Lanli [School of Materials Science and Engineering, Shanghai University, Shanghai 200444 (China); Shi, Siqi, E-mail: sqshi@shu.edu.cn [School of Materials Science and Engineering, Shanghai University, Shanghai 200444 (China); Materials Genome Institute, Shanghai University, Shanghai 200444 (China); Ishaq, Ahmad [National Center for Physics, Quaid-I-Azam University, Islamabad 44000 (Pakistan); Luo, Hongjie [School of Materials Science and Engineering, Shanghai University, Shanghai 200444 (China); Materials Genome Institute, Shanghai University, Shanghai 200444 (China); Gao, Yanfeng, E-mail: yfgao@shu.edu.cn [School of Materials Science and Engineering, Shanghai University, Shanghai 200444 (China)

2017-03-01

Graphical abstract: VO{sub 2}(B) thin films with high TCR and suitable resistance were first achieved by W doping. The mechanism for performance improvement was studied by first-principles calculations. The two-dimensional octahedral structure of VO{sub 2}(B) favors the strain control with W-doping for achieving a large TCR, which overcomes the contradiction between the high conductivity and large TCR generated by dopants in VO{sub 2}(M). - Highlights: • High performance W-doped VO{sub 2}(B) thin films were first achieved by co-sputtering. • Mechanism for performance improvement was studied by first-principles calculations. • The two-dimensional octahedral structure of VO{sub 2} (B) favors the strain control. • Achieved VO{sub 2} films possess high thermal sensitivity (TCR: −3.9%/K & R{sub 0}: 32.7 kΩ). - Abstract: VO{sub 2}(B) is currently a preferred phase structure for the application as bolometer material, which, however, suffers from low temperature-coefficient-of-resistance (TCR) values and large resistances. Here we present the combined experimental and first-principles calculations study on both doped and undoped VO{sub 2}(B) thin films enabling us to attain high TCR (−3.9%/k) and suitable square-resistance (32.7 kΩ) by controlled W doping employing the widely used magnetron sputtering technique. The TCR value is 50% larger than reported ones at the similar resistance. The underlying microscopic mechanism for the performance improvement was studied and results indicated that the introduction of extra electrons and the variation in the band structure resulting from the incorporation of W{sup 6+} ions in the VO{sub 2}(B) crystal lattice contribute to the enhancement of the electronic conductivity. Moreover, the special two-dimensional octahedral structure of monoclinic (C2/m) B-phase VO{sub 2} favors the strain control with W-doping for achieving a large TCR, which overcomes the analogous predicament between the high conductivity and large TCR

Achieving High Resolution Timer Events in Virtualized Environment.

Science.gov (United States)

Adamczyk, Blazej; Chydzinski, Andrzej

2015-01-01

Virtual Machine Monitors (VMM) have become popular in different application areas. Some applications may require to generate the timer events with high resolution and precision. This however may be challenging due to the complexity of VMMs. In this paper we focus on the timer functionality provided by five different VMMs-Xen, KVM, Qemu, VirtualBox and VMWare. Firstly, we evaluate resolutions and precisions of their timer events. Apparently, provided resolutions and precisions are far too low for some applications (e.g. networking applications with the quality of service). Then, using Xen virtualization we demonstrate the improved timer design that greatly enhances both the resolution and precision of achieved timer events.

Polymer-Particle Pressure-Sensitive Paint with High Photostability

Directory of Open Access Journals (Sweden)

Yu Matsuda

2016-04-01

Full Text Available We propose a novel fast-responding and paintable pressure-sensitive paint (PSP based on polymer particles, i.e. polymer-particle (pp-PSP. As a fast-responding PSP, polymer-ceramic (PC-PSP is widely studied. Since PC-PSP generally consists of titanium (IV oxide (TiO2 particles, a large reduction in the luminescent intensity will occur due to the photocatalytic action of TiO2. We propose the usage of polymer particles instead of TiO2 particles to prevent the reduction in the luminescent intensity. Here, we fabricate pp-PSP based on the polystyrene particle with a diameter of 1 μm, and investigate the pressure- and temperature-sensitives, the response time, and the photostability. The performances of pp-PSP are compared with those of PC-PSP, indicating the high photostability with the other characteristics comparable to PC-PSP.

Instruction manual for ORNL tandem high abundance sensitivity mass spectrometer

International Nuclear Information System (INIS)

Smith, D.H.; McKown, H.S.; Chrisite, W.H.; Walker, R.L.; Carter, J.A.

1976-06-01

This manual describes the physical characteristics of the tandem mass spectrometer built by Oak Ridge National Laboratory for the International Atomic Energy Agency. Specific requirements met include ability to run small samples, high abundance sensitivity, good precision and accuracy, and adequate sample throughput. The instrument is capable of running uranium samples as small as 10 -12 g and has an abundance sensitivity in excess of 10 6 . Precision and accuracy are enhanced by a special sweep control circuit. Sample throughput is 6 to 12 samples per day. Operating instructions are also given

Spectral and Concentration Sensitivity of Multijunction Solar Cells at High Temperature: Preprint

Energy Technology Data Exchange (ETDEWEB)

Friedman, Daniel J.; Steiner, Myles A.; Perl, Emmett E.; Simon, John

2017-06-14

We model the performance of two-junction solar cells at very high temperatures of ~400 degrees C and beyond for applications such as hybrid PV/solar-thermal power production, and identify areas in which the design and performance characteristics behave significantly differently than at more conventional near-room-temperature operating conditions. We show that high-temperature operation reduces the sensitivity of the cell efficiency to spectral content, but increases the sensitivity to concentration, both of which have implications for energy yield in terrestrial PV applications. For other high-temperature applications such as near-sun space missions, our findings indicate that concentration may be a useful tool to enhance cell efficiency.

Introducing wet aerosols into the static high sensitivity ICP (SHIP)

Energy Technology Data Exchange (ETDEWEB)

Scheffer, Andy; Engelhard, Carsten; Sperling, Michael; Buscher, Wolfgang [University of Muenster, Institute of Inorganic and Analytical Chemistry, Muenster (Germany)

2007-08-15

A demountable design of the static high sensitivity ICP (SHIP) for optical emission spectrometry is presented, and its use as an excitation source with the introduction of wet aerosols was investigated. Aerosols were produced by standard pneumatic sample introduction systems, namely a cross flow nebulizer, Meinhard nebulizer and PFA low flow nebulizer, which have been applied in conjunction with a double pass and a cyclonic spray chamber. The analytical capabilities of these sample introduction systems in combination with the SHIP system were evaluated with respect to the achieved sensitivity. It was found that a nebulizer tailored for low argon flow rates (0.3-0.5 L min{sup -1}) is best suited for the low flow plasma (SHIP). An optimization of all gas flow rates of the SHIP system with the PFA low flow nebulizer was carried out in a two-dimensional way with the signal to background ratio (SBR) and the robustness as optimization target parameters. Optimum conditions for a torch model with 1-mm injector tube were 0.25 and 0.36 L min{sup -1} for the plasma gas and the nebulizer gas, respectively. A torch model with a 2-mm injector tube was optimized to 0.4 L min{sup -1} for the plasma gas and 0.44 L min{sup -1} for the nebulizer gas. In both cases the SHIP system saves approximately 95% of the argon consumed by conventional inductively coupled plasma systems. The limits of detection were found to be in the low microgram per litre range and below for many elements, which was quite comparable to those of the conventional setup. Furthermore, the short-term stability and the wash out behaviour of the SHIP were investigated. Direct comparison with the conventional setup indicated that no remarkable memory effects were caused by the closed design of the torch. The analysis of a NIST SRM 1643e (Trace Elements in Water) with the SHIP yielded recoveries of 97-103% for 13 elements, measured simultaneously. (orig.)

Challenges to achievement of metal sustainability in our high-tech society.

Science.gov (United States)

Izatt, Reed M; Izatt, Steven R; Bruening, Ronald L; Izatt, Neil E; Moyer, Bruce A

2014-04-21

Achievement of sustainability in metal life cycles from mining of virgin ore to consumer and industrial devices to end-of-life products requires greatly increased recycling rates and improved processing of metals using conventional and green chemistry technologies. Electronic and other high-tech products containing precious, toxic, and specialty metals usually have short lifetimes and low recycling rates. Products containing these metals generally are incinerated, discarded as waste in landfills, or dismantled in informal recycling using crude and environmentally irresponsible procedures. Low recycling rates of metals coupled with increasing demand for high-tech products containing them necessitate increased mining with attendant environmental, health, energy, water, and carbon-footprint consequences. In this tutorial review, challenges to achieving metal sustainability, including projected use of urban mining, in present high-tech society are presented; health, environmental, and economic incentives for various government, industry, and public stakeholders to improve metal sustainability are discussed; a case for technical improvements, including use of molecular recognition, in selective metal separation technology, especially for metal recovery from dilute feed stocks is given; and global consequences of continuing on the present path are examined.

New and highly sensitive assay for L-5-hydroxytryptophan decarboxylase activity by high-performance liquid chromatography-voltammetry.

Science.gov (United States)

Rahman, M K; Nagatsu, T; Kato, T

1980-12-12

This paper describes a new, inexpensive and highly sensitive assay for aromatic L-amino acid decarboxylase (AADC) activity, using L-5-hydroxytryptophan (L-5-HTP) as substrate, in rat and human brains and serum by high-performance liquid chromatography (HPLC) with voltammetric detection. L-5-HTP was used as substrate and D-5-HTP for the blank. After isolating serotonin (5-HT) formed enzymatically from L-5-HTP on a small Amberlite CG-50 column, the 5-HT was eluted with hydrochloric acid and assayed by HPLC with a voltammetric detector. N-Methyldopamine was added to each incubation mixture as an internal standard. This method is sensitive enough to measure 5-HT, formed by the enzyme, 100 fmol to 140 pmol or more. An advantage of this method is that one can incubate the enzyme for longer time (up to 150 min), as compared with AADC assay using L-DOPA as substrate, resulting in a very high sensitivity. By using this new method, AADC activity was discovered in rat serum.

Effects of full-time and part-time high-ability programs on developments in students’ achievement emotions

NARCIS (Netherlands)

Hornstra, L.; van der Veen, I.; Peetsma, T.

2017-01-01

This study focused on effects of high-ability programs on students’ achievement emotions, i.e. emotions that students experience that are associated with achievement activities. Participants were students in grade 4–6 of primary education: 218 students attended full-time high-ability programs, 245

Resilience influence, goals and social context in the academic achievement of high school students

Directory of Open Access Journals (Sweden)

José Concepción Gaxiola Romero

2012-05-01

Full Text Available The academic achievement in high school students of Mexico, according to national and international evaluations has been insufficient. In spite of this situation, is possible to find excellent students, even in the context of sharing negative contextual and physical conditions. There are few investigations that describe the variables associated to resilient students. The alumni that are beyond the risks are called resilient (Rutter, 2007. The aim of this research was to explore and identify the internal variables: goals and resilience, and the external variables: risky neighborhood and risky friends that predicted the scholar achievement of high school students. To measure those variables, was used a compilation of scales validated in the region. The data were analyzed using structural equation modeling, and show that resilience predicted indirectly the scholar achievement trough the academic goals. The results could be used in programs to improve the academic achievement of this group of students.

Dye-sensitized solar cells for efficient power generation under ambient lighting

Science.gov (United States)

Freitag, Marina; Teuscher, Joël; Saygili, Yasemin; Zhang, Xiaoyu; Giordano, Fabrizio; Liska, Paul; Hua, Jianli; Zakeeruddin, Shaik M.; Moser, Jacques-E.; Grätzel, Michael; Hagfeldt, Anders

2017-06-01

Solar cells that operate efficiently under indoor lighting are of great practical interest as they can serve as electric power sources for portable electronics and devices for wireless sensor networks or the Internet of Things. Here, we demonstrate a dye-sensitized solar cell (DSC) that achieves very high power-conversion efficiencies (PCEs) under ambient light conditions. Our photosystem combines two judiciously designed sensitizers, coded D35 and XY1, with the copper complex Cu(II/I)(tmby) as a redox shuttle (tmby, 4,4‧,6,6‧-tetramethyl-2,2‧-bipyridine), and features a high open-circuit photovoltage of 1.1 V. The DSC achieves an external quantum efficiency for photocurrent generation that exceeds 90% across the whole visible domain from 400 to 650 nm, and achieves power outputs of 15.6 and 88.5 μW cm-2 at 200 and 1,000 lux, respectively, under illumination from a model Osram 930 warm-white fluorescent light tube. This translates into a PCE of 28.9%.

Molecularly Engineered Ru(II) Sensitizers Compatible with Cobalt(II/III) Redox Mediators for Dye-Sensitized Solar Cells.

Science.gov (United States)

Wu, Kuan-Lin; Huckaba, Aron J; Clifford, John N; Yang, Ya-Wen; Yella, Aswani; Palomares, Emilio; Grätzel, Michael; Chi, Yun; Nazeeruddin, Mohammad Khaja

2016-08-01

Thiocyanate-free isoquinazolylpyrazolate Ru(II) complexes were synthesized and applied as sensitizers in dye-sensitized solar cells (DSCs). Unlike most other successful Ru sensitizers, Co-based electrolytes were used, and resulting record efficiency of 9.53% was obtained under simulated sunlight with an intensity of 100 mW cm(-2). Specifically, dye 51-57dht.1 and an electrolyte based on Co(phen)3 led to measurement of a JSC of 13.89 mA cm(-2), VOC of 900 mV, and FF of 0.762 to yield 9.53% efficiency. The improved device performances were achieved by the inclusion of 2-hexylthiophene units onto the isoquinoline subunits, in addition to lengthening the perfluoroalkyl chain on the pyrazolate chelating group, which worked to increase light absorption and decrease recombination effects when using the Co-based electrolyte. As this study shows, Ru(II) sensitizers bearing sterically demanding ligands can allow successful utilization of important Co electrolytes and high performance.

Highly Sensitive Colorimetric Assay for Determining Fe3+ Based on Gold Nanoparticles Conjugated with Glycol Chitosan

Directory of Open Access Journals (Sweden)

Kyungmin Kim

2017-01-01

Full Text Available A highly sensitive and simple colorimetric assay for the detection of Fe3+ ions was developed using gold nanoparticles (AuNPs conjugated with glycol chitosan (GC. The Fe3+ ion coordinates with the oxygen atoms of GC in a hexadentate manner (O-Fe3+-O, decreasing the interparticle distance and inducing aggregation. Time-of-flight secondary ion mass spectrometry showed that the bound Fe3+ was coordinated to the oxygen atoms of the ethylene glycol in GC, which resulted in a significant color change from light red to dark midnight blue due to aggregation. Using this GC-AuNP probe, the quantitative determination of Fe3+ in biological, environmental, and pharmaceutical samples could be achieved by the naked eye and spectrophotometric methods. Sensitive response and pronounced color change of the GC-AuNPs in the presence of Fe3+ were optimized at pH 6, 70°C, and 300 mM NaCl concentration. The absorption intensity ratio (A700/A510 linearly correlated to the Fe3+ concentration in the linear range of 0–180 μM. The limits of detection were 11.3, 29.2, and 46.0 nM for tap water, pond water, and iron supplement tablets, respectively. Owing to its facile and sensitive nature, this assay method for Fe3+ ions can be applied to the analysis of drinking water and pharmaceutical samples.

Nitrogen detected TROSY at high field yields high resolution and sensitivity for protein NMR

International Nuclear Information System (INIS)

Takeuchi, Koh; Arthanari, Haribabu; Shimada, Ichio; Wagner, Gerhard

2015-01-01

Detection of 15 N in multidimensional NMR experiments of proteins has sparsely been utilized because of the low gyromagnetic ratio (γ) of nitrogen and the presumed low sensitivity of such experiments. Here we show that selecting the TROSY components of proton-attached 15 N nuclei (TROSY 15 N H ) yields high quality spectra in high field magnets (>600 MHz) by taking advantage of the slow 15 N transverse relaxation and compensating for the inherently low 15 N sensitivity. The 15 N TROSY transverse relaxation rates increase modestly with molecular weight but the TROSY gain in peak heights depends strongly on the magnetic field strength. Theoretical simulations predict that the narrowest line width for the TROSY 15 N H component can be obtained at 900 MHz, but sensitivity reaches its maximum around 1.2 GHz. Based on these considerations, a 15 N-detected 2D 1 H– 15 N TROSY-HSQC ( 15 N-detected TROSY-HSQC) experiment was developed and high-quality 2D spectra were recorded at 800 MHz in 2 h for 1 mM maltose-binding protein at 278 K (τ c  ∼ 40 ns). Unlike for 1 H detected TROSY, deuteration is not mandatory to benefit 15 N detected TROSY due to reduced dipolar broadening, which facilitates studies of proteins that cannot be deuterated, especially in cases where production requires eukaryotic expression systems. The option of recording 15 N TROSY of proteins expressed in H 2 O media also alleviates the problem of incomplete amide proton back exchange, which often hampers the detection of amide groups in the core of large molecular weight proteins that are expressed in D 2 O culture media and cannot be refolded for amide back exchange. These results illustrate the potential of 15 N H -detected TROSY experiments as a means to exploit the high resolution offered by high field magnets near and above 1 GHz

A highly sensitive RF-to-DC power converter with an extended dynamic range

KAUST Repository

Almansouri, Abdullah Saud Mohammed

2017-10-24

This paper proposes a highly sensitive RF-to-DC power converter with an extended dynamic range that is designed to operate at the medical band 433 MHz and simulated using 0.18 μm CMOS technology. Compared to the conventional fully cross-coupled rectifier, the proposed design offers 3.2× the dynamic range. It is also highly sensitive and requires −18 dBm of input power to produce a 1 V-output voltage when operating with a 100 kΩ load. Furthermore, the proposed design offers an open circuit sensitivity of −23.4 dBm and a peak power conversion efficiency of 67%.

Spatial Experiences of High Academic Achievers: Insights from a Developmental Perspective

Science.gov (United States)

Weckbacher, Lisa Marie; Okamoto, Yukari

2012-01-01

The study explored the relationship between types of spatial experiences and spatial abilities among 13- to 14-year-old high academic achievers. Each participant completed two spatial tasks and a survey assessing favored spatial activities across five categories (computers, toys, sports, music, and art) and three developmental periods (early…

Real-time, single-step bioassay using nanoplasmonic resonator with ultra-high sensitivity

Energy Technology Data Exchange (ETDEWEB)

Zhang, Xiang; Ellman, Jonathan A; Chen, Fanqing Frank; Su, Kai-Hang; Wei, Qi-Huo; Sun, Cheng

2014-04-01

A nanoplasmonic resonator (NPR) comprising a metallic nanodisk with alternating shielding layer(s), having a tagged biomolecule conjugated or tethered to the surface of the nanoplasmonic resonator for highly sensitive measurement of enzymatic activity. NPRs enhance Raman signals in a highly reproducible manner, enabling fast detection of protease and enzyme activity, such as Prostate Specific Antigen (paPSA), in real-time, at picomolar sensitivity levels. Experiments on extracellular fluid (ECF) from paPSA-positive cells demonstrate specific detection in a complex bio-fluid background in real-time single-step detection in very small sample volumes.

Transitioning high sensitivity cardiac troponin I (hs-cTnI) into routine diagnostic use: More than just a sensitivity issue

LENUS (Irish Health Repository)

Lee, Graham R

2016-04-01

High sensitivity cardiac troponin T and I (hs-cTnT and hs-cTnI) assays show analytical, diagnostic and prognostic improvement over contemporary sensitive cTn assays. However, given the importance of troponin in the diagnosis of myocardial infarction, implementing this test requires rigorous analytical and clinical verification across the total testing pathway. This was the aim of this study.

Performance of high-resolution position-sensitive detectors developed for storage-ring decay experiments

International Nuclear Information System (INIS)

Yamaguchi, T.; Suzaki, F.; Izumikawa, T.; Miyazawa, S.; Morimoto, K.; Suzuki, T.; Tokanai, F.; Furuki, H.; Ichihashi, N.; Ichikawa, C.; Kitagawa, A.; Kuboki, T.; Momota, S.; Nagae, D.; Nagashima, M.; Nakamura, Y.; Nishikiori, R.; Niwa, T.; Ohtsubo, T.; Ozawa, A.

2013-01-01

Highlights: • Position-sensitive detectors were developed for storage-ring decay spectroscopy. • Fiber scintillation and silicon strip detectors were tested with heavy ion beams. • A new fiber scintillation detector showed an excellent position resolution. • Position and energy detection by silicon strip detectors enable full identification. -- Abstract: As next generation spectroscopic tools, heavy-ion cooler storage rings will be a unique application of highly charged RI beam experiments. Decay spectroscopy of highly charged rare isotopes provides us important information relevant to the stellar conditions, such as for the s- and r-process nucleosynthesis. In-ring decay products of highly charged RI will be momentum-analyzed and reach a position-sensitive detector set-up located outside of the storage orbit. To realize such in-ring decay experiments, we have developed and tested two types of high-resolution position-sensitive detectors: silicon strips and scintillating fibers. The beam test experiments resulted in excellent position resolutions for both detectors, which will be available for future storage-ring experiments

High hunger state increases olfactory sensitivity to neutral but not food odors.

Science.gov (United States)

Stafford, Lorenzo D; Welbeck, Kimberley

2011-01-01

Understanding how hunger state relates to olfactory sensitivity has become more urgent due to their possible role in obesity. In 2 studies (within-subjects: n = 24, between-subjects: n = 40), participants were provided with lunch before (satiated state) or after (nonsatiated state) testing and completed a standardized olfactory threshold test to a neutral odor (Experiments 1 and 2) and discrimination test to a food odor (Experiment 2). Experiment 1 revealed that olfactory sensitivity was greater in the nonsatiated versus satiated state, with additionally increased sensitivity for the low body mass index (BMI) compared with high BMI group. Experiment 2 replicated this effect for neutral odors, but in the case of food odors, those in a satiated state had greater acuity. Additionally, whereas the high BMI group had higher acuity to food odors in the satiated versus nonsatiated state, no such differences were found for the low BMI group. The research here is the first to demonstrate how olfactory acuity changes as a function of hunger state and relatedness of odor to food and that BMI can predict differences in olfactory sensitivity.

Nitrogen-Doped Graphene/Platinum Counter Electrodes for Dye-Sensitized Solar Cells

KAUST Repository

Lin, Chinan; Lee, Chuanpei; Ho, Shute; Wei, Tzuchiao; Chi, Yuwen; Huang, Kunping; He, Jr-Hau

2014-01-01

Nitrogen-doped graphene (NGR) was utilized in dye-sensitized solar cells for energy harvesting. NGR on a Pt-sputtered fluorine-doped tin oxide substrate (NGR/Pt/FTO) as counter electrodes (CEs) achieves the high efficiency of 9.38% via the nitrogen

The Effect of Technology Integration on High School Students' Literacy Achievement

Science.gov (United States)

Robinson, Kara

2016-01-01

This literature review presents a critical appraisal of current research on the role technology integration plays in high school students' literacy achievement. It identifies the gaps within the research through comprehensive analysis. The review develops an argument that the use of laptops in secondary English classrooms has a significant impact…

Highly Sensitive and Selective Gas Sensor Using Hydrophilic and Hydrophobic Graphenes

Science.gov (United States)

Some, Surajit; Xu, Yang; Kim, Youngmin; Yoon, Yeoheung; Qin, Hongyi; Kulkarni, Atul; Kim, Taesung; Lee, Hyoyoung

2013-01-01

New hydrophilic 2D graphene oxide (GO) nanosheets with various oxygen functional groups were employed to maintain high sensitivity in highly unfavorable environments (extremely high humidity, strong acidic or basic). Novel one-headed polymer optical fiber sensor arrays using hydrophilic GO and hydrophobic reduced graphene oxide (rGO) were carefully designed, leading to the selective sensing of volatile organic gases for the first time. The two physically different surfaces of GO and rGO could provide the sensing ability to distinguish between tetrahydrofuran (THF) and dichloromethane (MC), respectively, which is the most challenging issue in the area of gas sensors. The eco-friendly physical properties of GO allowed for faster sensing and higher sensitivity when compared to previous results for rGO even under extreme environments of over 90% humidity, making it the best choice for an environmentally friendly gas sensor. PMID:23736838

Nuclear Symbiosis - A Means to Achieve Sustainable Nuclear Growth While Limiting the Spread of Sensitive Nuclear Technology

International Nuclear Information System (INIS)

Shropshire, David

2009-01-01

Global growth of nuclear energy in the 21. century is creating new challenges to limit the spread of nuclear technology without hindering adoption in countries now considering nuclear power. Independent nuclear states desire autonomy over energy choices and seek energy independence. However, this independence comes with high costs for development of new indigenous fuel cycle capabilities. Nuclear supplier states and expert groups have proposed fuel supply assurance mechanisms such as fuel take-back services, international enrichment services and fuel banks in exchange for recipient state concessions on the development of sensitive technologies. Recipient states are slow to accept any concessions to their rights under the Non Proliferation Treaty. To date, decisions to not develop indigenous fuel enrichment capabilities have been driven by economics. However, additional incentives may be required in the future to offset the user state's perceived loss of energy independence. In order for a country to forgo development of sensitive nuclear capabilities, the basis for an equitable economic tradeoff must be established. This paper proposes that the nuclear trade-off can be made through a combination of fuel supply assurances, leveraging work by the United Nations and International Atomic Energy Agency on sustainable nuclear development, and use of 'nuclear symbiosis'. The primary focus of this paper is on how nuclear symbiosis could be used to achieve a user-state's desired economic, energy, and infrastructure development end states. The desired result from this 'symbiosis' is a nuclear-centered industrial complex that creates new economic opportunities through infrastructure improvements, human resource skills development and the development of new sustainable industries. This paper also describes the Nuclear Materials Exchange (NME) as a practical tool for performing nuclear symbiosis. The NME can be used to define existing and new international nuclear resources and

Applications of molecules as high-resolution, high-sensitivity threshold electron detectors

International Nuclear Information System (INIS)

Chutjian, A.

1991-01-01

The goal of the work under the contract entitled ''Applications of Molecules as High-Resolution, High-Sensitivity Threshold Electron Detectors'' (DoE IAA No. DE-AI01-83ER13093 Mod. A006) was to explore the electron attachment properties of a variety of molecules at electron energies not accessible by other experimental techniques. As a result of this work, not only was a large body of basic data measured on attachment cross sections and rate constants; but also extensive theoretical calculations were carried out to verify the underlying phenomenon of s-wave attachment. Important outgrowths of this week were also realized in other areas of research. The basic data have applications in fields such as combustion, soot reduction, rocket-exhaust modification, threshold photoelectron spectroscopy, and trace species detection

Phase Sensitive Amplification using Parametric Processes in Optical Fibers

DEFF Research Database (Denmark)

Kang, Ning

. Further, phase sensitive parametric processes in a nano-engineered silicon waveguide have been measured experimentally for the first time. Numerical optimizations show that with reduced waveguide propagation loss and reduced carrier life time, larger signal phase sensitive extinction ratio is achievable......Phase sensitive amplification using the parametric processes in fiber has the potential of delivering high gain and broadband operation with ultralow noise. It is able to regenerate both amplitude and phase modulated signals, simultaneously, with the appropriate design. This thesis concerns...... types. The regeneration capability of PSAs on phase encoded signal in an optical link has been optimized. Flat-top phase sensitive profile has been synthesized. It is able to provide simultaneous amplitude and phase noise squeezing, with enhanced phase noise margin compared to conventional designs...

High resolution, high sensitivity imaging and analysis of minerals and inclusions (fluid and melt) using the new CSIRO-GEMOC nuclear microprobe

International Nuclear Information System (INIS)

Ryan, C.G.; McInnes, B.M.; Van Achterbergh, E.; Williams, P.J.; Dong, G.; Zaw, K.

1999-01-01

Full text: The new CSIRO-GEMOC Nuclear Microprobe (NMP) The instrument was designed specifically for minerals analysis and imaging and to achieve ppm to sub-ppm sensitivity at a spatial resolution of 1-2 μm using X-rays and y-rays induced by MeV energy ion beams. The key feature of the design is a unique magnetic quadrupole quintuplet ion focussing system that combines high current with high spatial resolution (Ryan et al., 1999). These design goals have been achieved or exceeded. On the first day of operation, a spot-size of 1.3 μm was obtained at a beam current of 0.5 nA, suitable for fluid inclusion analysis and imaging. The spot-size grows to just 1.8 μm at 10 nA (3 MeV protons), ideal for mineralogical samples with detection limits down to 0.2 ppm achieved in quantitative, high resolution, trace element images. Applications of the NMP include: research into ore deposit processes through trace element geochemistry, mineralogy and fluid inclusion analysis of ancient deposits and active sea-floor environments, ore characterization, and fundamental studies of mantle processes and extraterrestrial material. Quantitative True Elemental Imaging Dynamic Analysis is a method for projecting quantitative major and trace element images from proton-induced X-ray emission (PIXE) data obtained using the NMP (Ryan et al., 1995). The method un-mixes full elemental spectral signatures to produce quantitative images that can be directly interrogated for the concentrations of all elements in selected areas or line projections, etc. Fluid Inclusion Analysis and Imaging The analysis of fluids trapped as fluid inclusions in minerals holds the key to understanding ore metal pathways and ore formation processes. PIXE analysis using the NMP provides a direct non-destructive method to determine the composition of these trapped fluids with detection limits down to 20 ppm. However, some PIXE results have been controversial, such as the strong partitioning of Cu into the vapour phase (e

Highly sensitive electrochemical determination of 1-naphthol based on high-index facet SnO2 modified electrode

International Nuclear Information System (INIS)

Huang Xiaofeng; Zhao Guohua; Liu Meichuan; Li Fengting; Qiao Junlian; Zhao Sichen

2012-01-01

Highlights: ► It is the first time to employ high-index faceted SnO 2 in electrochemical analysis. ► High-index faceted SnO 2 has excellent electrochemical activity toward 1-naphthol. ► Highly sensitive determination of 1-naphthol is realized on high-index faceted SnO 2 . ► The detection limit of 1-naphthol is as low as 5 nM on high-index faceted SnO 2 . ► Electro-oxidation kinetics for 1-napthol on the novel electrode is discussed. - Abstract: SnO 2 nanooctahedron with {2 2 1} high-index facet (HIF) was synthesized by a simple hydrothermal method, and was firstly employed to sensitive electrochemical sensing of a typical organic pollutant, 1-naphthol (1-NAP). The constructed HIF SnO 2 modified glassy carbon electrode (HIF SnO 2 /GCE) possessed advantages of large effective electrode area, high electron transfer rate, and low charge transfer resistance. These improved electrochemical properties allowed the high electrocatalytic performance, high effective active sites and high adsorption capacity of 1-NAP on HIF SnO 2 /GCE. Cyclic voltammetry (CV) results showed that the electrochemical oxidation of 1-NAP obeyed a two-electron transfer process and the electrode reaction was under diffusion control on HIF SnO 2 /GCE. By adopting differential pulse voltammetry (DPV), electrochemical detection of 1-NAP was conducted on HIF SnO 2 /GCE with a limit of detection as low as 5 nM, which was relatively low compared to the literatures. The electrode also illustrated good stability in comparison with those reported value. Satisfactory results were obtained with average recoveries in the range of 99.7–103.6% in the real water sample detection. A promising device for the electrochemical detection of 1-NAP with high sensitivity has therefore been provided.

Generating high temperature tolerant transgenic plants: Achievements and challenges.

Science.gov (United States)

Grover, Anil; Mittal, Dheeraj; Negi, Manisha; Lavania, Dhruv

2013-05-01

Production of plants tolerant to high temperature stress is of immense significance in the light of global warming and climate change. Plant cells respond to high temperature stress by re-programming their genetic machinery for survival and reproduction. High temperature tolerance in transgenic plants has largely been achieved either by over-expressing heat shock protein genes or by altering levels of heat shock factors that regulate expression of heat shock and non-heat shock genes. Apart from heat shock factors, over-expression of other trans-acting factors like DREB2A, bZIP28 and WRKY proteins has proven useful in imparting high temperature tolerance. Besides these, elevating the genetic levels of proteins involved in osmotic adjustment, reactive oxygen species removal, saturation of membrane-associated lipids, photosynthetic reactions, production of polyamines and protein biosynthesis process have yielded positive results in equipping transgenic plants with high temperature tolerance. Cyclic nucleotide gated calcium channel proteins that regulate calcium influxes across the cell membrane have recently been shown to be the key players in induction of high temperature tolerance. The involvement of calmodulins and kinases in activation of heat shock factors has been implicated as an important event in governing high temperature tolerance. Unfilled gaps limiting the production of high temperature tolerant transgenic plants for field level cultivation are discussed. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Immobilization of Ni–Pd/core–shell nanoparticles through thermal polymerization of acrylamide on glassy carbon electrode for highly stable and sensitive glutamate detection

International Nuclear Information System (INIS)

Yu, Huicheng; Ma, Zhenzhen; Wu, Zhaoyang

2015-01-01

The preparation of a persistently stable and sensitive biosensor is highly important for practical applications. To improve the stability and sensitivity of glutamate sensors, an electrode modified with glutamate dehydrogenase (GDH)/Ni–Pd/core–shell nanoparticles was developed using the thermal polymerization of acrylamide (AM) to immobilize the synthesized Ni–Pd/core–shell nanoparticles onto a glassy carbon electrode (GCE). The modified electrode was characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). Electrochemical data showed that the prepared biosensor had remarkably enhanced electrocatalytic activity toward glutamate. Moreover, superior reproducibility and excellent stability were observed (relative average deviation was 2.96% after continuous use of the same sensor for 60 times, and current responses remained at 94.85% of the initial value after 60 d). The sensor also demonstrated highly sensitive amperometric detection of glutamate with a low limit of detection (0.052 μM, S/N = 3), high sensitivity (4.768 μA μM"−"1 cm"−"2), and a wide, useful linear range (0.1–500 μM). No interference from potential interfering species such as L-cysteine, ascorbic acid, and L-aspartate were noted. The determination of glutamate levels in actual samples achieved good recovery percentages. - Highlights: • Ni–Pd/core–shell nanoparticles were synthesized. • Nanoparticles were immobilized onto electrodes through thermal polymerization. • The modified sensor exhibited excellent stability and sensitivity for glutamate detection. • The biosensor exhibited remarkable electrocatalytic activity toward glutamate. • The sensor successfully detected glutamate in tomato soup samples.

Immobilization of Ni–Pd/core–shell nanoparticles through thermal polymerization of acrylamide on glassy carbon electrode for highly stable and sensitive glutamate detection

Energy Technology Data Exchange (ETDEWEB)

Yu, Huicheng, E-mail: doyhc@126.com [State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082 (China); School of Chemistry and Chemical Engineering, Guangxi University for Nationalities, Nanning, 530008 (China); School of Chemistry and Chemical Engineering, Guangxi University for Nationalities, Nanning, 530008 (China); Key Laboratory of Chemistry and Engineering of Forest Products, Guangxi University for Nationalities, Nanning, 530008 (China); Key Laboratory of Guangxi Colleges and Universities for Food Safety and Pharmaceutical Analytical Chemistry, Guangxi University for Nationalities, Nanning, 530008 (China); Ma, Zhenzhen [State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082 (China); Wu, Zhaoyang, E-mail: zywu@hnu.edu.cn [State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082 (China)

2015-10-08

The preparation of a persistently stable and sensitive biosensor is highly important for practical applications. To improve the stability and sensitivity of glutamate sensors, an electrode modified with glutamate dehydrogenase (GDH)/Ni–Pd/core–shell nanoparticles was developed using the thermal polymerization of acrylamide (AM) to immobilize the synthesized Ni–Pd/core–shell nanoparticles onto a glassy carbon electrode (GCE). The modified electrode was characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). Electrochemical data showed that the prepared biosensor had remarkably enhanced electrocatalytic activity toward glutamate. Moreover, superior reproducibility and excellent stability were observed (relative average deviation was 2.96% after continuous use of the same sensor for 60 times, and current responses remained at 94.85% of the initial value after 60 d). The sensor also demonstrated highly sensitive amperometric detection of glutamate with a low limit of detection (0.052 μM, S/N = 3), high sensitivity (4.768 μA μM{sup −1} cm{sup −2}), and a wide, useful linear range (0.1–500 μM). No interference from potential interfering species such as L-cysteine, ascorbic acid, and L-aspartate were noted. The determination of glutamate levels in actual samples achieved good recovery percentages. - Highlights: • Ni–Pd/core–shell nanoparticles were synthesized. • Nanoparticles were immobilized onto electrodes through thermal polymerization. • The modified sensor exhibited excellent stability and sensitivity for glutamate detection. • The biosensor exhibited remarkable electrocatalytic activity toward glutamate. • The sensor successfully detected glutamate in tomato soup samples.

Inkjet-assisted layer-by-layer printing of quantum dot/enzyme microarrays for highly sensitive detection of organophosphorous pesticides

Energy Technology Data Exchange (ETDEWEB)

Luan, Enxiao; Zheng, Zhaozhu; Li, Xinyu; Gu, Hongxi [State Key Laboratory of Urban Water Resource and Environment, School of Life Science and Technology, Harbin Institute of Technology, Harbin 150080 (China); Micro- and Nanotechnology Research Center, Harbin Institute of Technology, Harbin 150080 (China); Liu, Shaoqin, E-mail: shaoqinliu@hit.edu.cn [Micro- and Nanotechnology Research Center, Harbin Institute of Technology, Harbin 150080 (China)

2016-04-15

We present a facile fabrication of layer-by-layer (LbL) microarrays of quantum dots (QDs) and acetylcholinesterase enzyme (AChE). The resulting arrays had several unique properties, such as low cost, high integration and excellent flexibility and time–saving. The presence of organophosphorous pesticides (OPs) can inhibit the AChE activity and thus changes the fluorescent intensity of QDs/AChE microscopic dot arrays. Therefore, the QDs/AChE microscopic dot arrays were used for the sensitive visual detection of OPs. Linear calibration for parathion and paraoxon was obtained in the range of 5–100 μg L{sup −1} under the optimized conditions with the limit of detection (LOD) of 10 μg L{sup −1}. The arrays have been successfully used for detection of OPs in fruits and water real samples. The new array was validated by comparison with conventional high performance liquid chromatography-mass spectrometry (HPLC-MS). - Graphical abstract: A fluorimetric assay for high-throughput screening of organophosphorous pesticides was developed based on the CdTe QDs/AChE microarrays via inkjet-assisted LbL printing techniques. - Highlights: • The large scale microarrays of CdTe QDs and AChE were fabricated by facile inkjet-assisted LbL printing technique. • The QDs/AChE microscopic dot arrays could be used quantitatively and rapidly for the sensitively visual detection of OPs. • A detection limit of 10 μg L{sup −1} was achieved, much lower than levels specified by standard tests and other colorimetric detection methods. • The low cost, short processing time, sufficient sensitivity, good stability and ease of use make it for a facile platform for on-site screening.

Moving to higher ground: Closing the high school science achievement gap

Science.gov (United States)

Mebane, Joyce Graham

The purpose of this study was to examine the perceptions of West High School constituents (students, parents, teachers, administrators, and guidance counselors) about the readiness and interest of African American students at West High School to take Advanced Placement (AP) and International Baccalaureate (IB) science courses as a strategy for closing the achievement gap. This case study utilized individual interviews and questionnaires for data collection. The participants were selected biology students and their parents, teachers, administrators, and guidance counselors at West High School. The results of the study indicated that just over half the students and teachers, most parents, and all guidance counselors thought African American students were prepared to take AP science courses. Only one of the three administrators thought the students were prepared to take AP science courses. Between one-half and two-thirds of the students, parents, teachers, and administrators thought students were interested in taking an AP science course. Only two of the guidance counselors thought there was interest among the African American students in taking AP science courses. The general consensus among the constituents about the readiness and interest of African American students at West High School to take IB science courses was that it is too early in the process to really make definitive statements. West is a prospective IB school and the program is new and not yet in place. Educators at the West High School community must find reasons to expect each student to succeed. Lower expectations often translate into lower academic demands and less rigor in courses. Lower academic demands and less rigor in courses translate into less than adequate performance by students. When teachers and administrators maintain high expectations, they encourage students to aim high rather than slide by with mediocre effort (Lumsden, 1997). As a result of the study, the following suggestions should

Eating high fat chow increases the sensitivity of rats to 8-OH-DPAT-induced lower lip retraction.

Science.gov (United States)

Li, Jun-Xu; Ju, Shutian; Baladi, Michelle G; Koek, Wouter; France, Charles P

2011-12-01

Eating high fat food can alter sensitivity to drugs acting on dopamine systems; this study examined whether eating high fat food alters sensitivity to a drug acting on serotonin (5-HT) systems. Sensitivity to (+)-8-hydroxy-2-(dipropylamino) tetralin hydrobromide (8-OH-DPAT; 5-HT1A receptor agonist)-induced lower lip retraction was examined in separate groups (n=8-9) of rats with free access to standard (5.7% fat) or high fat (34.3% fat) chow; sensitivity to quinpirole (dopamine D3/D2 receptor agonist)-induced yawning was also examined. Rats eating high fat chow gained more body weight than rats eating standard chow and, after 6 weeks of eating high fat chow, they were more sensitive to 8-OH-DPAT (0.01-0.1 mg/kg)-induced lower lip retraction and quinpirole (0.0032-0.32 mg/kg)-induced yawning. These changes were not reversed when rats that previously ate high fat chow were switched to eating standard chow and sensitivity to 8-OH-DPAT and quinpirole increased when rats that previously ate standard chow ate high fat chow. These data extend previous results showing changes in sensitivity to drugs acting on dopamine systems in animals eating high fat chow to a drug acting at 5-HT1A receptors and they provide support for the notion that eating certain foods impacts sensitivity to drugs acting on monoamine systems.

Mass Spectrometry-based Assay for High Throughput and High Sensitivity Biomarker Verification

Energy Technology Data Exchange (ETDEWEB)

Guo, Xuejiang; Tang, Keqi

2017-06-14

Searching for disease specific biomarkers has become a major undertaking in the biomedical research field as the effective diagnosis, prognosis and treatment of many complex human diseases are largely determined by the availability and the quality of the biomarkers. A successful biomarker as an indicator to a specific biological or pathological process is usually selected from a large group of candidates by a strict verification and validation process. To be clinically useful, the validated biomarkers must be detectable and quantifiable by the selected testing techniques in their related tissues or body fluids. Due to its easy accessibility, protein biomarkers would ideally be identified in blood plasma or serum. However, most disease related protein biomarkers in blood exist at very low concentrations (<1ng/mL) and are “masked” by many none significant species at orders of magnitude higher concentrations. The extreme requirements of measurement sensitivity, dynamic range and specificity make the method development extremely challenging. The current clinical protein biomarker measurement primarily relies on antibody based immunoassays, such as ELISA. Although the technique is sensitive and highly specific, the development of high quality protein antibody is both expensive and time consuming. The limited capability of assay multiplexing also makes the measurement an extremely low throughput one rendering it impractical when hundreds to thousands potential biomarkers need to be quantitatively measured across multiple samples. Mass spectrometry (MS)-based assays have recently shown to be a viable alternative for high throughput and quantitative candidate protein biomarker verification. Among them, the triple quadrupole MS based assay is the most promising one. When it is coupled with liquid chromatography (LC) separation and electrospray ionization (ESI) source, a triple quadrupole mass spectrometer operating in a special selected reaction monitoring (SRM) mode

High-resolution and high sensitivity mesoscopic fluorescence tomography based on de-scanning EMCCD: System design and thick tissue imaging applications

Science.gov (United States)

Ozturk, Mehmet Saadeddin

Optical microscopy has been one of the essential tools for biological studies for decades, however, its application areas was limited to superficial investigation due to strong scattering in live tissues. Even though advanced techniques such as confocal or multiphoton methods have been recently developed to penetrate beyond a few hundreds of microns deep in tissues, they still cannot perform in the mesoscopic regime (millimeter scale) without using destructive sample preparation protocols such as clearing techniques. They provide rich cellular information; however, they cannot be readily employed to investigate the biological processes at larger scales. Herein, we will present our effort to establish a novel imaging approach that can quantify molecular expression in intact tissues, well beyond the current microscopy depth limits. Mesoscopic Fluorescence Molecular Tomography (MFMT) is an emerging imaging modality that offers unique potential for the non-invasive molecular assessment of thick in-vitro and in-vivo live tissues. This novel imaging modality is based on an optical inverse problem that allows for retrieval of the quantitative spatial distribution of fluorescent tagged bio-markers at millimeter depth. MFMT is well-suited for in-vivo subsurface tissue imaging and thick bio-printed specimens due to its high sensitivity and fast acquisition times, as well as relatively large fields of view. Herein, we will first demonstrate the potential of this technique using our first generation MFMT system applied to multiplexed reporter gene imaging (in-vitro) and determination of Photodynamic Therapy (PDT) agent bio-distribution in a mouse model (in-vivo). Second, we will present the design rationale, in silico benchmarking, and experimental validation of a second generation MFMT (2GMFMT) system. We will demonstrate the gain in resolution and sensitivity achieved due to the de-scanned dense detector configuration implemented. The potential of this novel platform will be

High-Sensitivity Measurement of Density by Magnetic Levitation.

Science.gov (United States)

Nemiroski, Alex; Kumar, A A; Soh, Siowling; Harburg, Daniel V; Yu, Hai-Dong; Whitesides, George M

2016-03-01

This paper presents methods that use Magnetic Levitation (MagLev) to measure very small differences in density of solid diamagnetic objects suspended in a paramagnetic medium. Previous work in this field has shown that, while it is a convenient method, standard MagLev (i.e., where the direction of magnetization and gravitational force are parallel) cannot resolve differences in density mm) because (i) objects close in density prevent each other from reaching an equilibrium height due to hard contact and excluded volume, and (ii) using weaker magnets or reducing the magnetic susceptibility of the medium destabilizes the magnetic trap. The present work investigates the use of weak magnetic gradients parallel to the faces of the magnets as a means of increasing the sensitivity of MagLev without destabilization. Configuring the MagLev device in a rotated state (i.e., where the direction of magnetization and gravitational force are perpendicular) relative to the standard configuration enables simple measurements along the axes with the highest sensitivity to changes in density. Manipulating the distance of separation between the magnets or the lengths of the magnets (along the axis of measurement) enables the sensitivity to be tuned. These modifications enable an improvement in the resolution up to 100-fold over the standard configuration, and measurements with resolution down to 10(-6) g/cm(3). Three examples of characterizing the small differences in density among samples of materials having ostensibly indistinguishable densities-Nylon spheres, PMMA spheres, and drug spheres-demonstrate the applicability of rotated Maglev to measuring the density of small (0.1-1 mm) objects with high sensitivity. This capability will be useful in materials science, separations, and quality control of manufactured objects.

High School Success: An Effective Intervention for Achievement and Dropout Prevention

Science.gov (United States)

Lowder, Christopher Michael

2012-01-01

The purpose of this mixed-design study was to use quantitative and qualitative research to explore the effects of High School Success (a course for at-risk ninth graders) and its effectiveness on student achievement, attendance, and dropout prevention. The research questions address whether there is a significant difference between at-risk ninth…

Effects of Part-Time Work on School Achievement During High School

Science.gov (United States)

Singh, Kusum; Chang, Mido; Dika, Sandra

2007-01-01

The authors explored the effects of part-time work on school achievement during high school. To estimate the true effects of part-time work on school grades, the authors included family background, students' educational aspirations, and school engagement as controls. Although a substantial literature exists on the relationship of part-time work…

Hyperbranched quasi-1D nanostructures for solid-state dye-sensitized solar cells.

Science.gov (United States)

Passoni, Luca; Ghods, Farbod; Docampo, Pablo; Abrusci, Agnese; Martí-Rujas, Javier; Ghidelli, Matteo; Divitini, Giorgio; Ducati, Caterina; Binda, Maddalena; Guarnera, Simone; Li Bassi, Andrea; Casari, Carlo Spartaco; Snaith, Henry J; Petrozza, Annamaria; Di Fonzo, Fabio

2013-11-26

In this work we demonstrate hyperbranched nanostructures, grown by pulsed laser deposition, composed of one-dimensional anatase single crystals assembled in arrays of high aspect ratio hierarchical mesostructures. The proposed growth mechanism relies on a two-step process: self-assembly from the gas phase of amorphous TiO2 clusters in a forest of tree-shaped hierarchical mesostructures with high aspect ratio; oriented crystallization of the branches upon thermal treatment. Structural and morphological characteristics can be optimized to achieve both high specific surface area for optimal dye uptake and broadband light scattering thanks to the microscopic feature size. Solid-state dye sensitized solar cells fabricated with arrays of hyperbranched TiO2 nanostructures on FTO-glass sensitized with D102 dye showed a significant 66% increase in efficiency with respect to a reference mesoporous photoanode and reached a maximum efficiency of 3.96% (among the highest reported for this system). This result was achieved mainly thanks to an increase in photogenerated current directly resulting from improved light harvesting efficiency of the hierarchical photoanode. The proposed photoanode overcomes typical limitations of 1D TiO2 nanostructures applied to ss-DSC and emerges as a promising foundation for next-generation high-efficiency solid-state devices comprosed of dyes, polymers, or quantum dots as sensitizers.

Working Memory Load and Reminder Effect on Event-Based Prospective Memory of High- and Low-Achieving Students in Math.

Science.gov (United States)

Chen, Youzhen; Lian, Rong; Yang, Lixian; Liu, Jianrong; Meng, Yingfang

The effects of working memory (WM) demand and reminders on an event-based prospective memory (PM) task were compared between students with low and high achievement in math. WM load (1- and 2-back tasks) was manipulated as a within-subject factor and reminder (with or without reminder) as a between-subject factor. Results showed that high-achieving students outperformed low-achieving students on all PM and n-back tasks. Use of a reminder improved PM performance and thus reduced prospective interference; the performance of ongoing tasks also improved for all students. Both PM and n-back performances in low WM load were better than in high WM load. High WM load had more influence on low-achieving students than on high-achieving students. Results suggest that low-achieving students in math were weak at PM and influenced more by high WM load. Thus, it is important to train these students to set up an obvious reminder for their PM and improve their WM.

MicroRNA-triggered, cascaded and catalytic self-assembly of functional ``DNAzyme ferris wheel'' nanostructures for highly sensitive colorimetric detection of cancer cells

Science.gov (United States)

Zhou, Wenjiao; Liang, Wenbin; Li, Xin; Chai, Yaqin; Yuan, Ruo; Xiang, Yun

2015-05-01

The construction of DNA nanostructures with various sizes and shapes has significantly advanced during the past three decades, yet the application of these DNA nanostructures for solving real problems is still in the early stage. On the basis of microRNA-triggered, catalytic self-assembly formation of the functional ``DNAzyme ferris wheel'' nanostructures, we show here a new signal amplification platform for highly sensitive, label-free and non-enzyme colorimetric detection of a small number of human prostate cancer cells. The microRNA (miR-141), which is catalytically recycled and reused, triggers isothermal self-assembly of a pre-designed, G-quadruplex sequence containing hairpin DNAs into ``DNAzyme ferris wheel''-like nanostructures (in association with hemin) with horseradish peroxidase mimicking activity. These DNAzyme nanostructures catalyze an intensified color transition of the probe solution for highly sensitive detection of miR-141 down to 0.5 pM with the naked eye, and the monitoring of as low as 283 human prostate cancer cells can also, theoretically, be achieved in a colorimetric approach. The work demonstrated here thus offers new opportunities for the construction of functional DNA nanostructures and for the application of these DNA nanostructures as an effective signal amplification means in the sensitive detection of nucleic acid biomarkers.

Scintillating fibre detectors using position-sensitive photomultipliers

International Nuclear Information System (INIS)

Agoritsas, V.; Bergdolt, A.M.; Bing, O.; Bravar, A.; Ditta, J.; Drevenak, R.

1995-01-01

Scintillating fibre technology has made substantial progress, and has demonstrated great potential for fast tracking and triggering in high luminosity experiments in Particle Physics. Some recent issues of the RD-17 project at CERN are presented for fast and precise readout of scintillating fibre arrays, as well as for upgrade of position-sensitive photomultipliers. Excellent matching of the scintillating fibre and the position-sensitive photomultiplier, in particular in time characteristics, allowed to achieve excellent detector performances, typically a spatial resolution of ∼ 125 μm with time resolution better than 1 ns and detection efficiency greater than 95%. (author)10 refs.; 25 figs.; 1 tab

High sensitivity phase retrieval method in grating-based x-ray phase contrast imaging

Energy Technology Data Exchange (ETDEWEB)

Wu, Zhao; Gao, Kun; Chen, Jian; Wang, Dajiang; Wang, Shenghao; Chen, Heng; Bao, Yuan; Shao, Qigang; Wang, Zhili, E-mail: wangnsrl@ustc.edu.cn [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029 (China); Zhang, Kai [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Zhu, Peiping; Wu, Ziyu, E-mail: wuzy@ustc.edu.cn [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, China and Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)

2015-02-15

Purpose: Grating-based x-ray phase contrast imaging is considered as one of the most promising techniques for future medical imaging. Many different methods have been developed to retrieve phase signal, among which the phase stepping (PS) method is widely used. However, further practical implementations are hindered, due to its complex scanning mode and high radiation dose. In contrast, the reverse projection (RP) method is a novel fast and low dose extraction approach. In this contribution, the authors present a quantitative analysis of the noise properties of the refraction signals retrieved by the two methods and compare their sensitivities. Methods: Using the error propagation formula, the authors analyze theoretically the signal-to-noise ratios (SNRs) of the refraction images retrieved by the two methods. Then, the sensitivities of the two extraction methods are compared under an identical exposure dose. Numerical experiments are performed to validate the theoretical results and provide some quantitative insight. Results: The SNRs of the two methods are both dependent on the system parameters, but in different ways. Comparison between their sensitivities reveals that for the refraction signal, the RP method possesses a higher sensitivity, especially in the case of high visibility and/or at the edge of the object. Conclusions: Compared with the PS method, the RP method has a superior sensitivity and provides refraction images with a higher SNR. Therefore, one can obtain highly sensitive refraction images in grating-based phase contrast imaging. This is very important for future preclinical and clinical implementations.

High sensitivity phase retrieval method in grating-based x-ray phase contrast imaging

International Nuclear Information System (INIS)

Wu, Zhao; Gao, Kun; Chen, Jian; Wang, Dajiang; Wang, Shenghao; Chen, Heng; Bao, Yuan; Shao, Qigang; Wang, Zhili; Zhang, Kai; Zhu, Peiping; Wu, Ziyu

2015-01-01

Purpose: Grating-based x-ray phase contrast imaging is considered as one of the most promising techniques for future medical imaging. Many different methods have been developed to retrieve phase signal, among which the phase stepping (PS) method is widely used. However, further practical implementations are hindered, due to its complex scanning mode and high radiation dose. In contrast, the reverse projection (RP) method is a novel fast and low dose extraction approach. In this contribution, the authors present a quantitative analysis of the noise properties of the refraction signals retrieved by the two methods and compare their sensitivities. Methods: Using the error propagation formula, the authors analyze theoretically the signal-to-noise ratios (SNRs) of the refraction images retrieved by the two methods. Then, the sensitivities of the two extraction methods are compared under an identical exposure dose. Numerical experiments are performed to validate the theoretical results and provide some quantitative insight. Results: The SNRs of the two methods are both dependent on the system parameters, but in different ways. Comparison between their sensitivities reveals that for the refraction signal, the RP method possesses a higher sensitivity, especially in the case of high visibility and/or at the edge of the object. Conclusions: Compared with the PS method, the RP method has a superior sensitivity and provides refraction images with a higher SNR. Therefore, one can obtain highly sensitive refraction images in grating-based phase contrast imaging. This is very important for future preclinical and clinical implementations

Gold nanoparticles embedded electropolymerized thin film of pyrimidine derivative on glassy carbon electrode for highly sensitive detection of l-cysteine.

Science.gov (United States)

Kannan, Ayyadurai; Sevvel, Ranganathan

2017-09-01

This paper demonstrates the fabrication of novel gold nanoparticles incorporated poly (4-amino-6-hydroxy-2-mercaptopyrimidine) (Nano-Au/Poly-AHMP) film modified glassy carbon electrode and it is employed for highly sensitive detection of l-cysteine (CYS). The modified electrode was characterized by scanning electron microscope (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). SEM images of modified electrode revealed the homogeneous distribution of gold nanoparticles on poly (4-amino-6-hydroxy-2-mercaptopyrimidine) thin film modified glassy carbon electrode. The modified electrode was successfully utilized for highly selective and sensitive determination of l-cysteine at physiological pH7.0. The present electrochemical sensor successfully resolved the voltammetric signals of ascorbic acid (AA) and l-cysteine with peak separation of 0.510V. To the best of our knowledge, this is the first report of larger peak separation between AA and CYS. Wide linear concentration ranges (2μM-500μM), low detection limit (0.020μM), an excellent reproducibility and stability are achieved for cysteine sensing with this Nano-Au/Poly-AHMP/GCE. Copyright © 2017 Elsevier B.V. All rights reserved.

Mindmapping: Its effects on student achievement in high school biology

Science.gov (United States)

Cunningham, Glennis Edge

The primary goal of schools is to promote the highest degree of learning possible. Yet teachers spend the majority of their time engaged in lecturing while students spend the majority of their time passively present (Cawelti, 1997, Grinder, 1991; Jackson & Davis, 2000; Jenkins, 1996). Helping students develop proficiency in learning, which translates into using that expertise to construct knowledge in subject domains, is a crucial goal of education. Students need exposure to teaching and learning practices that prepare them for both the classroom and their places in the future workforce (Ettinger, 1998; Longley, Goodchild, Maguire, & Rhind, 2001; NRC, 1996; Texley & Wild, 1996). The purpose of this study was to determine if achievement in high school science courses could be enhanced utilizing mindmapping. The subjects were primarily 9th and 10th graders (n = 147) at a suburban South Texas high school. A pretest-posttest control group design was selected to determine the effects of mindmapping on student achievement as measured by a teacher-developed, panel-validated instrument. Follow-up interviews were conducted with the teacher and a purposive sample of students (n = 7) to determine their perceptions of mindmapping and its effects on teaching and learning. Mindmapping is a strategy for visually displaying large amounts of conceptual, hierarchical information in a concise, organized, and accessible format. Mindmaps arrange information similar to that found on the traditional topic outline into colorful spatial displays that offer the user a view of the "forest" as well as the "trees" (Hyerle, 1996; Wandersee, 1990b). An independent samples t-test and a one-way analysis of covariance (ANCOVA) determined no significant difference in achievement between the groups. The experimental group improved in achievement at least as much as the control group. Several factors may have played a role in the lack of statistically significant results. These factors include the

A highly sensitive and durable electrical sensor for liquid ethanol using thermally-oxidized mesoporous silicon

Science.gov (United States)

Harraz, Farid A.; Ismail, Adel A.; Al-Sayari, S. A.; Al-Hajry, A.; Al-Assiri, M. S.

2016-12-01

A capacitive detection of liquid ethanol using reactive, thermally oxidized films constructed from electrochemically synthesized porous silicon (PSi) is demonstrated. The sensor elements are fabricated as meso-PSi (pore sizes hydrophobic PSi surface exhibited almost a half sensitivity of the thermal oxide sensor. The response to water is achieved only at the oxidized surface and found to be ∼one quarter of the ethanol sensitivity, dependent on parameters such as vapor pressure and surface tension. The capacitance response retains ∼92% of its initial value after continuous nine cyclic runs and the sensors presumably keep long-term stability after three weeks storage, demonstrating excellent durability and storage stability. The observed behavior in current system is likely explained by the interface interaction due to dipole moment effect. The results suggest that the current sensor structure and design can be easily made to produce notably higher sensitivities for reversible detection of various analytes.

High-sensitivity C-reactive protein predicts target organ damage in Chinese patients with metabolic syndrome

DEFF Research Database (Denmark)

Zhao, Zhigang; Nie, Hai; He, Hongbo

2007-01-01

with metabolic syndrome. A total of 1082 consecutive patients of Chinese origin were screened for the presence of metabolic syndrome according to the National Cholesterol Education Program's Adult Treatment Panel III. High-sensitivity C-reactive protein and target organ damage, including cardiac hypertrophy......Observational studies established high-sensitivity C-reactive protein as a risk factor for cardiovascular events in the general population. The goal of this study was to determine the relationship between target organ damage and high-sensitivity C-reactive protein in a cohort of Chinese patients......, carotid intima-media thickness, and renal impairment, were investigated. The median (25th and 75th percentiles) of high-sensitivity C-reactive protein in 619 patients with metabolic syndrome was 2.42 mg/L (0.75 and 3.66 mg/L) compared with 1.13 mg/L (0.51 and 2.46 mg/L) among 463 control subjects (P

Effects of Full-Time and Part-Time High-Ability Programs on Developments in Students' Achievement Emotions

Science.gov (United States)

Hornstra, Lisette; van der Veen, Ineke; Peetsma, Thea

2017-01-01

This study focused on effects of high-ability programs on students' achievement emotions, i.e. emotions that students experience that are associated with achievement activities. Participants were students in grade 4-6 of primary education: 218 students attended full-time high-ability programs, 245 attended part-time high-ability programs (i.e.…

Highly sensitive wearable strain sensor based on silver nanowires and nanoparticles

Science.gov (United States)

Shengbo, Sang; Lihua, Liu; Aoqun, Jian; Qianqian, Duan; Jianlong, Ji; Qiang, Zhang; Wendong, Zhang

2018-06-01

Here, we propose a highly sensitive and stretchable strain sensor based on silver nanoparticles and nanowires (Ag NPs and NWs), advancing the rapid development of electronic skin. To improve the sensitivity of strain sensors based on silver nanowires (Ag NWs), Ag NPs and NWs were added to polydimethylsiloxane (PDMS) as an aid filler. Silver nanoparticles (Ag NPs) increase the conductive paths for electrons, leading to the low resistance of the resulting sensor (14.9 Ω). The strain sensor based on Ag NPs and NWs showed strong piezoresistivity with a tunable gauge factor (GF) at 3766, and a change in resistance as the strain linearly increased from 0% to 28.1%. The high GF demonstrates the irreplaceable role of Ag NPs in the sensor. Moreover, the applicability of our high-performance strain sensor has been demonstrated by its ability to sense movements caused by human talking, finger bending, wrist raising and walking.

Achieving high data throughput in research networks

International Nuclear Information System (INIS)

Matthews, W.; Cottrell, L.

2001-01-01

After less than a year of operation, the BaBar experiment at SLAC has collected almost 100 million particle collision events in a database approaching 165TB. Around 20 TB of data has been exported via the Internet to the BaBar regional center at IN2P3 in Lyon, France, and around 40TB of simulated data has been imported from the Lawrence Livermore National Laboratory (LLNL). BaBar collaborators plan to double data collection each year and export a third of the data to IN2P3. So within a few years the SLAC OC3 (155 Mbps) connection will be fully utilized by file transfer to France alone. Upgrades to infrastructure is essential and detailed understanding of performance issues and the requirements for reliable high throughput transfers is critical. In this talk results from active and passive monitoring and direct measurements of throughput will be reviewed. Methods for achieving the ambitious requirements will be discussed

Achieving High Data Throughput in Research Networks

International Nuclear Information System (INIS)

Matthews, W

2004-01-01

After less than a year of operation, the BaBar experiment at SLAC has collected almost 100 million particle collision events in a database approaching 165TB. Around 20 TB of data has been exported via the Internet to the BaBar regional center at IN2P3 in Lyon, France, and around 40TB of simulated data has been imported from the Lawrence Livermore National Laboratory (LLNL). BaBar collaborators plan to double data collection each year and export a third of the data to IN2P3. So within a few years the SLAC OC3 (155Mbps) connection will be fully utilized by file transfer to France alone. Upgrades to infrastructure is essential and detailed understanding of performance issues and the requirements for reliable high throughput transfers is critical. In this talk results from active and passive monitoring and direct measurements of throughput will be reviewed. Methods for achieving the ambitious requirements will be discussed

Design of a high-sensitivity classifier based on a genetic algorithm: application to computer-aided diagnosis

International Nuclear Information System (INIS)

Sahiner, Berkman; Chan, Heang-Ping; Petrick, Nicholas; Helvie, Mark A.; Goodsitt, Mitchell M.

1998-01-01

A genetic algorithm (GA) based feature selection method was developed for the design of high-sensitivity classifiers, which were tailored to yield high sensitivity with high specificity. The fitness function of the GA was based on the receiver operating characteristic (ROC) partial area index, which is defined as the average specificity above a given sensitivity threshold. The designed GA evolved towards the selection of feature combinations which yielded high specificity in the high-sensitivity region of the ROC curve, regardless of the performance at low sensitivity. This is a desirable quality of a classifier used for breast lesion characterization, since the focus in breast lesion characterization is to diagnose correctly as many benign lesions as possible without missing malignancies. The high-sensitivity classifier, formulated as the Fisher's linear discriminant using GA-selected feature variables, was employed to classify 255 biopsy-proven mammographic masses as malignant or benign. The mammograms were digitized at a pixel size of 0.1mmx0.1mm, and regions of interest (ROIs) containing the biopsied masses were extracted by an experienced radiologist. A recently developed image transformation technique, referred to as the rubber-band straightening transform, was applied to the ROIs. Texture features extracted from the spatial grey-level dependence and run-length statistics matrices of the transformed ROIs were used to distinguish malignant and benign masses. The classification accuracy of the high-sensitivity classifier was compared with that of linear discriminant analysis with stepwise feature selection (LDA sfs ). With proper GA training, the ROC partial area of the high-sensitivity classifier above a true-positive fraction of 0.95 was significantly larger than that of LDA sfs , although the latter provided a higher total area (A z ) under the ROC curve. By setting an appropriate decision threshold, the high-sensitivity classifier and LDA sfs correctly

Giant magnetoimpedance intrinsic impedance and voltage sensitivity of rapidly solidified Co{sub 66}Fe{sub 2}Cr{sub 4}Si{sub 13}B{sub 15} amorphous wire for highly sensitive sensors applications

Energy Technology Data Exchange (ETDEWEB)

Das, Tarun K.; Mandal, Sushil K. [CSIR - National Metallurgical Laboratory, NDE and Magnetic Materials Group, MST Division, Jamshedpur (India); Banerji, Pallab [Indian Institute of Technology, Kharagpur, Materials Science Centre, Kharagpur (India)

2016-11-15

We report a systematic study of the influence of wire length, L, dependence of giant magneto-impedance (GMI) sensitivity of Co{sub 66}Fe{sub 2}Cr{sub 4}Si{sub 13}B{sub 15} soft magnetic amorphous wire of diameter ∝ 100 μm developed by in-water quenching technique. The magnetization behaviour (hysteresis loops) of the wire with different length (L = 1, 2, 3, 5, 8 and 10 cm) has been evaluated by fuxmetric induction method. It was observed that the behaviour of the hysteresis loops change drastically with the wire length, being attributed to the existence of a critical length, L{sub C}, found to be around 3 cm. GMI measurements have been taken using automated GMI measurement system and the GMI sensitivities in terms of intrinsic impedance sensitivity (S{sub Ω/Am}{sup -1}) and voltage sensitivity (S{sub V/Am}{sup -1}) of the wire have been evaluated under optimal bias field and excitation current. It was found that the maximum (S{sub Ω/Am}{sup -1}){sub max} ∼ 0.63 Ω/kAm{sup -1}/cm and (S{sub V/Am}{sup -1}){sub max} ∼ 3.10 V/kAm{sup -1}/cm were achieved at a critical length L{sub C} ∝ 3 cm of the wire for an AC current of 5 mA and a frequency of 5 MHz. These findings provide crucial insights for optimization of the geometrical dimensions of magnetic sensing elements and important practical guidance for designing high sensitive GMI sensors. The relevant combinations of magnetic material parameters and operating conditions that optimize the sensitivity are highlighted. (orig.)

Radiation sensitive solid state devices

International Nuclear Information System (INIS)

Shannon, J.M.; Ralph, J.E.

1975-01-01

A solid state radiation sensitive device is described employing JFETs as the sensitive elements. Two terminal construction is achieved by using a common conductor to capacitively couple to the JFET gate and to one of the source and drain connections. (auth)

The High-Potential Fast-Flying Achiever: Themes from the English Language Literature 1976-1995.

Science.gov (United States)

Altman, Yochanan

1997-01-01

Review of business management literature from the United States, United Kingdom, and Canada identified the following: the images of high flyer, fast track, and high achiever; the meaning of success; emphasis on performance; corporate rites of passage; and opportunities for women to be high flyers. (SK)

The Effect of the Time Management Art on Academic Achievement among High School Students in Jordan

Science.gov (United States)

Al-Zoubi, Maysoon

2016-01-01

This study aimed at recognizing the effect of the Time Management Art on academic achievement among high school students in the Hashemite Kingdom of Jordan. The researcher employed the descriptive-analytic research to achieve the purpose of the study where he chose a sample of (2000) high school female and male students as respondents to the…

A novel immunochromatographic electrochemical biosensor for highly sensitive and selective detection of trichloropyridinol, a biomarker of exposure to chlorpyrifos.

Science.gov (United States)

Wang, Limin; Lu, Donglai; Wang, Jun; Du, Dan; Zou, Zhexiang; Wang, Hua; Smith, Jordan N; Timchalk, Charles; Liu, Fengquan; Lin, Yuehe

2011-02-15

We present a novel portable immunochromatographic electrochemical biosensor (IEB) for simple, rapid, and sensitive biomonitoring of trichloropyridinol (TCP), a metabolite biomarker of exposure to organophosphorus insecticides. Our new approach takes the advantage of immunochromatographic test strip for a rapid competitive immunoreaction and a disposable screen-printed carbon electrode for a rapid and sensitive electrochemical analysis of captured HRP labeling. Several key experimental parameters (e.g. immunoreaction time, the amount of HRP labeled TCP, concentration of the substrate for electrochemical measurements, and the blocking agents for the nitrocellulose membrane) were optimized to achieve a high sensitivity, selectivity and stability. Under optimal conditions, the IEB has demonstrated a wide linear range (0.1-100 ng/ml) with a detection limit as low as 0.1 ng/ml TCP. Furthermore, the IEB has been successfully applied for biomonitoring of TCP in the rat plasma samples with in vivo exposure to organophosphorus insecticides like Chlorpyrifos-oxon (CPF-oxon). The IEB thus opens up new pathways for designing a simple, rapid, clinically accurate, and quantitative tool for TCP detection, as well as holds a great promise for in-field screening of metabolite biomarkers, e.g., TCP, for humans exposed to organophosphorus insecticides. Copyright © 2010 Elsevier B.V. All rights reserved.

One-to-One Computing and Student Achievement in Ohio High Schools

Science.gov (United States)

Williams, Nancy L.; Larwin, Karen H.

2016-01-01

This study explores the impact of one-to-one computing on student achievement in Ohio high schools as measured by performance on the Ohio Graduation Test (OGT). The sample included 24 treatment schools that were individually paired with a similar control school. An interrupted time series methodology was deployed to examine OGT data over a period…

Highly sensitive detection of urinary cadmium to assess personal exposure

Energy Technology Data Exchange (ETDEWEB)

Argun, Avni A.; Banks, Ashley M.; Merlen, Gwendolynne; Tempelman, Linda A. [Giner, Inc., 89 Rumford Ave., Newton 02466, MA United States (United States); Becker, Michael F.; Schuelke, Thomas [Fraunhofer USA – CCL, 1449 Engineering Research Ct., East Lansing 48824, MI (United States); Dweik, Badawi M., E-mail: bdweik@ginerinc.com [Giner, Inc., 89 Rumford Ave., Newton 02466, MA United States (United States)

2013-04-22

Highlights: ► An electrochemical sensor capable of detecting cadmium at parts-per-billion levels in urine. ► A novel fabrication method for Boron-Doped Diamond (BDD) ultramicroelectrode (UME) arrays. ► Unique combination of BDD UME arrays and a differential pulse voltammetry algorithm. ► High sensitivity, high reproducibility, and very low noise levels. ► Opportunity for portable operation to assess on-site personal exposure. -- Abstract: A series of Boron-Doped Diamond (BDD) ultramicroelectrode arrays were fabricated and investigated for their performance as electrochemical sensors to detect trace level metals such as cadmium. The steady-state diffusion behavior of these sensors was validated using cyclic voltammetry followed by electrochemical detection of cadmium in water and in human urine to demonstrate high sensitivity (>200 μA ppb{sup −1} cm{sup −2}) and low background current (<4 nA). When an array of ultramicroelectrodes was positioned with optimal spacing, these BDD sensors showed a sigmoidal diffusion behavior. They also demonstrated high accuracy with linear dose dependence for quantification of cadmium in a certified reference river water sample from the U.S. National Institute of Standards and Technology (NIST) as well as in a human urine sample spiked with 0.25–1 ppb cadmium.

Incremental Theory of Intelligence Moderated the Relationship between Prior Achievement and School Engagement in Chinese High School Students.

Science.gov (United States)

Li, Ping; Zhou, Nan; Zhang, Yuchi; Xiong, Qing; Nie, Ruihong; Fang, Xiaoyi

2017-01-01

School engagement plays a prominent role in promoting academic accomplishments. In contrast to the relative wealth of research that examined the impact of students' school engagement on their academic achievement, considerably less research has investigated the effect of high school students' prior achievement on their school engagement. The present study examined the relationship between prior achievement and school engagement among Chinese high school students. Based on the Dweck's social-cognitive theory of motivation, we further examined the moderating effect of students' theories of intelligence (TOIs) on this relationship. A total of 4036 (2066 girls) students from five public high school enrolled in grades 10 reported their high school entrance exam achievement in Chinese, Math and English, school engagement, and TOIs. Results showed that (a) students' prior achievement predicted their behavioral, emotional, and cognitive engagement, respectively, and (b) the association between prior achievement and behavioral, emotional, and cognitive engagement is strong for students with an incremental theory but not for those with an entity theory in the emotional and cognitive engagement. These findings suggest that prior achievement and incremental theory were implicated in relation to adolescents' school engagement. Implications and future research directions were discussed.

Incremental Theory of Intelligence Moderated the Relationship between Prior Achievement and School Engagement in Chinese High School Students

Directory of Open Access Journals (Sweden)

Ping Li

2017-09-01

Full Text Available School engagement plays a prominent role in promoting academic accomplishments. In contrast to the relative wealth of research that examined the impact of students’ school engagement on their academic achievement, considerably less research has investigated the effect of high school students’ prior achievement on their school engagement. The present study examined the relationship between prior achievement and school engagement among Chinese high school students. Based on the Dweck’s social-cognitive theory of motivation, we further examined the moderating effect of students’ theories of intelligence (TOIs on this relationship. A total of 4036 (2066 girls students from five public high school enrolled in grades 10 reported their high school entrance exam achievement in Chinese, Math and English, school engagement, and TOIs. Results showed that (a students’ prior achievement predicted their behavioral, emotional, and cognitive engagement, respectively, and (b the association between prior achievement and behavioral, emotional, and cognitive engagement is strong for students with an incremental theory but not for those with an entity theory in the emotional and cognitive engagement. These findings suggest that prior achievement and incremental theory were implicated in relation to adolescents’ school engagement. Implications and future research directions were discussed.

The effects of chronic achievement motivation and achievement primes on the activation of achievement and fun goals.

Science.gov (United States)

Hart, William; Albarracín, Dolores

2009-12-01

This research examined the hypothesis that situational achievement cues can elicit achievement or fun goals depending on chronic differences in achievement motivation. In 4 studies, chronic differences in achievement motivation were measured, and achievement-denoting words were used to influence behavior. The effects of these variables were assessed on self-report inventories, task performance, task resumption following an interruption, and the pursuit of means relevant to achieving or having fun. Findings indicated that achievement priming (vs. control priming) activated a goal to achieve and inhibited a goal to have fun in individuals with chronically high-achievement motivation but activated a goal to have fun and inhibited a goal to achieve in individuals with chronically low-achievement motivation.

Enhanced fluorescence sensitivity by coupling yttrium-analyte complexes and three-way fast high-performance liquid chromatography data modeling

Energy Technology Data Exchange (ETDEWEB)

Alcaraz, Mirta R.; Culzoni, María J., E-mail: mculzoni@fbcb.unl.edu.ar; Goicoechea, Héctor C., E-mail: hgoico@fbcb.unl.edu.ar

2016-01-01

The present study reports a sensitive chromatographic method for the analysis of seven fluoroquinolones (FQs) in environmental water samples, by coupling yttrium-analyte complex and three-way chromatographic data modeling. This method based on the use of HPLC-FSFD does not require complex or tedious sample treatments or enrichment processes before the analysis, due to the significant fluorescence increments of the analytes reached by the presence of Y{sup 3+}. Enhancement achieved for the FQs signals obtained after Y{sup 3+} addition reaches 103- to 1743-fold. Prediction results corresponding to the application of MCR-ALS to the validation set showed relative error of prediction (REP%) values below 10% in all cases. A recovery study that includes the simultaneous determination of the seven FQs in three different environmental aqueous matrices was conducted. The recovery studies assert the efficiency and the accuracy of the proposed method. The LOD values calculated are in the order of part per trillion (below 0.5 ng mL{sup −1} for all the FQs, except for enoxacin). It is noteworthy to mention that the method herein proposed, which does not include pre-concentration steps, allows reaching LOD values in the same order of magnitude than those achieved by more sophisticated methods based on SPE and UHPLC-MS/MS. - Highlights: • Highly sensitive method for the analysis of seven fluoroquinolones. • Coupling of yttrium-analyte complex and three-way modeling. • Complex or tedious sample treatments or enrichment processes are nor required. • Accuracy on the quantitation of fluoroquinolones in real water river samples.

Online high sensitivity measurement system for transuranic aerosols

International Nuclear Information System (INIS)

Kordas, J.F.; Phelps, P.L.

1976-01-01

A measurement system for transuranic aerosols has been designed that will be able to withstand the corrosive nature of stack effluents and yet have extremely high sensitivity. It will be capable of measuring 1 maximum permissible concentration (MPC) of plutonium or americium in 30 minutes with a fractional standard deviation of less than 0.33. Background resulting from 218 Po is eliminated by alpha energy discrimination and a decay scheme analysis. A microprocessor controls all data acquisition, data reduction, and instrument calibration

High Excitation Transfer Efficiency from Energy Relay Dyes in Dye-Sensitized Solar Cells

KAUST Repository

Hardin, Brian E.

2010-08-11

The energy relay dye, 4-(Dicyanomethylene)-2-methyl-6-(4- dimethylaminostyryl)-4H-pyran (DCM), was used with a near-infrared sensitizing dye, TT1, to increase the overall power conversion efficiency of a dye-sensitized solar cell (DSC) from 3.5% to 4.5%. The unattached DCM dyes exhibit an average excitation transfer efficiency (EÌ?TE) of 96% inside TT1-covered, mesostructured TiO2 films. Further performance increases were limited by the solubility of DCM in an acetonitrile based electrolyte. This demonstration shows that energy relay dyes can be efficiently implemented in optimized dye-sensitized solar cells, but also highlights the need to design highly soluble energy relay dyes with high molar extinction coefficients. © 2010 American Chemical Society.

Highly Sensitive Liquid Core Temperature Sensor Based on Multimode Interference Effects

Directory of Open Access Journals (Sweden)

Miguel A. Fuentes-Fuentes

2015-10-01

Full Text Available A novel fiber optic temperature sensor based on a liquid-core multimode interference device is demonstrated. The advantage of such structure is that the thermo-optic coefficient (TOC of the liquid is at least one order of magnitude larger than that of silica and this, combined with the fact that the TOC of silica and the liquid have opposite signs, provides a liquid-core multimode fiber (MMF highly sensitive to temperature. Since the refractive index of the liquid can be easily modified, this allows us to control the modal properties of the liquid-core MMF at will and the sensor sensitivity can be easily tuned by selecting the refractive index of the liquid in the core of the device. The maximum sensitivity measured in our experiments is 20 nm/°C in the low-temperature regime up to 60 °C. To the best of our knowledge, to date, this is the largest sensitivity reported for fiber-based MMI temperature sensors.

Nitrogen detected TROSY at high field yields high resolution and sensitivity for protein NMR

Energy Technology Data Exchange (ETDEWEB)

Takeuchi, Koh [National Institute for Advanced Industrial Science and Technology, Molecular Profiling Research Center for Drug Discovery (Japan); Arthanari, Haribabu [Harvard Medical School, Department of Biochemistry and Molecular Pharmacology (United States); Shimada, Ichio, E-mail: shimada@iw-nmr.f.u-tokyo.ac.jp [National Institute for Advanced Industrial Science and Technology, Molecular Profiling Research Center for Drug Discovery (Japan); Wagner, Gerhard, E-mail: gerhard-wagner@hms.harvard.edu [Harvard Medical School, Department of Biochemistry and Molecular Pharmacology (United States)

2015-12-15

Detection of {sup 15}N in multidimensional NMR experiments of proteins has sparsely been utilized because of the low gyromagnetic ratio (γ) of nitrogen and the presumed low sensitivity of such experiments. Here we show that selecting the TROSY components of proton-attached {sup 15}N nuclei (TROSY {sup 15}N{sub H}) yields high quality spectra in high field magnets (>600 MHz) by taking advantage of the slow {sup 15}N transverse relaxation and compensating for the inherently low {sup 15}N sensitivity. The {sup 15}N TROSY transverse relaxation rates increase modestly with molecular weight but the TROSY gain in peak heights depends strongly on the magnetic field strength. Theoretical simulations predict that the narrowest line width for the TROSY {sup 15}N{sub H} component can be obtained at 900 MHz, but sensitivity reaches its maximum around 1.2 GHz. Based on these considerations, a {sup 15}N-detected 2D {sup 1}H–{sup 15}N TROSY-HSQC ({sup 15}N-detected TROSY-HSQC) experiment was developed and high-quality 2D spectra were recorded at 800 MHz in 2 h for 1 mM maltose-binding protein at 278 K (τ{sub c} ∼ 40 ns). Unlike for {sup 1}H detected TROSY, deuteration is not mandatory to benefit {sup 15}N detected TROSY due to reduced dipolar broadening, which facilitates studies of proteins that cannot be deuterated, especially in cases where production requires eukaryotic expression systems. The option of recording {sup 15}N TROSY of proteins expressed in H{sub 2}O media also alleviates the problem of incomplete amide proton back exchange, which often hampers the detection of amide groups in the core of large molecular weight proteins that are expressed in D{sub 2}O culture media and cannot be refolded for amide back exchange. These results illustrate the potential of {sup 15}N{sub H}-detected TROSY experiments as a means to exploit the high resolution offered by high field magnets near and above 1 GHz.

A novel and highly sensitive real-time nested RT-PCR assay in a single closed tube for detection of enterovirus.

Science.gov (United States)

Shen, Xin-Xin; Qiu, Fang-Zhou; Zhao, Huai-Long; Yang, Meng-Jie; Hong, Liu; Xu, Song-Tao; Zhou, Shuai-Feng; Li, Gui-Xia; Feng, Zhi-Shan; Ma, Xue-Jun

2018-03-01

The sensitivity of qRT-PCR assay is not adequate for the detection of the samples with lower viral load, particularly in the cerebrospinal fluid (CSF) of patients. Here, we present the development of a highly sensitive real-time nested RT-PCR (RTN RT-PCR) assay in a single closed tube for detection of human enterovirus (HEV). The clinical performance of both RTN RT-PCR and qRT-PCR was also tested and compared using 140 CSF and fecal specimens. The sensitivities of RTN RT-PCR assay for EV71, Coxsackievirus A (CVA)16, CVA6 and CVA10 achieved 10 -8 dilution with a corresponding Ct value of 38.20, 36.45, 36.75, and 36.45, respectively, which is equal to traditional two-step nested RT-PCR assay and approximately 2-10-fold lower than that of qRT-PCR assay. The specificity of RTN RT-PCR assay was extensively analyzed insilico and subsequently verified using the reference isolates and clinical samples. Sixteen qRT-PCR-negative samples were detected by RTN RT-PCR and a variety of enterovirus serotypes was identified by sequencing of inner PCR products. We conclude RTN RT-PCR is more sensitive than qRT-PCR for the detection of HEV in clinical samples. Copyright © 2017 Elsevier Inc. All rights reserved.

High resolution and high sensitivity methods for oligosaccharide mapping and characterization by normal phase high performance liquid chromatography following derivatization with highly fluorescent anthranilic acid.

Science.gov (United States)

Anumula, K R; Dhume, S T

1998-07-01

Facile labeling of oligosaccharides (acidic and neutral) in a nonselective manner was achieved with highly fluorescent anthranilic acid (AA, 2-aminobenzoic acid) (more than twice the intensity of 2-aminobenzamide, AB) for specific detection at very high sensitivity. Quantitative labeling in acetate-borate buffered methanol (approximately pH 5.0) at 80 degreesC for 60 min resulted in negligible or no desialylation of the oligosaccharides. A high resolution high performance liquid chromatographic method was developed for quantitative oligosaccharide mapping on a polymeric-NH2bonded (Astec) column operating under normal phase and anion exchange (NP-HPAEC) conditions. For isolation of oligosaccharides from the map by simple evaporation, the chromatographic conditions developed use volatile acetic acid-triethylamine buffer (approximately pH 4.0) systems. The mapping and characterization technology was developed using well characterized standard glycoproteins. The fluorescent oligosaccharide maps were similar to the maps obtained by the high pH anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD), except that the fluorescent maps contained more defined peaks. In the map, the oligosaccharides separated into groups based on charge, size, linkage, and overall structure in a manner similar to HPAEC-PAD with contribution of -COOH function from the label, anthranilic acid. However, selectivity of the column for sialic acid linkages was different. A second dimension normal phase HPLC (NP-HPLC) method was developed on an amide column (TSK Gel amide-80) for separation of the AA labeled neutral complex type and isomeric structures of high mannose type oligosaccharides. The oligosaccharides labeled with AA are compatible with biochemical and biophysical techniques, and use of matrix assisted laser desorption mass spectrometry for rapid determination of oligosaccharide mass map of glycoproteins is demonstrated. High resolution of NP-HPAEC and NP-HPLC methods

High spatial precision nano-imaging of polarization-sensitive plasmonic particles

Science.gov (United States)

Liu, Yunbo; Wang, Yipei; Lee, Somin Eunice

2018-02-01

Precise polarimetric imaging of polarization-sensitive nanoparticles is essential for resolving their accurate spatial positions beyond the diffraction limit. However, conventional technologies currently suffer from beam deviation errors which cannot be corrected beyond the diffraction limit. To overcome this issue, we experimentally demonstrate a spatially stable nano-imaging system for polarization-sensitive nanoparticles. In this study, we show that by integrating a voltage-tunable imaging variable polarizer with optical microscopy, we are able to suppress beam deviation errors. We expect that this nano-imaging system should allow for acquisition of accurate positional and polarization information from individual nanoparticles in applications where real-time, high precision spatial information is required.

Raising the stakes: How students' motivation for mathematics associates with high- and low-stakes test achievement.

Science.gov (United States)

Simzar, Rahila M; Martinez, Marcela; Rutherford, Teomara; Domina, Thurston; Conley, AnneMarie M

2015-04-01

This study uses data from an urban school district to examine the relation between students' motivational beliefs about mathematics and high- versus low-stakes math test performance. We use ordinary least squares and quantile regression analyses and find that the association between students' motivation and test performance differs based on the stakes of the exam. Students' math self-efficacy and performance avoidance goal orientation were the strongest predictors for both exams; however, students' math self-efficacy was more strongly related to achievement on the low-stakes exam. Students' motivational beliefs had a stronger association at the low-stakes exam proficiency cutoff than they did at the high-stakes passing cutoff. Lastly, the negative association between performance avoidance goals and high-stakes performance showed a decreasing trend across the achievement distribution, suggesting that performance avoidance goals are more detrimental for lower achieving students. These findings help parse out the ways motivation influences achievement under different stakes.

Peace of Mind, Academic Motivation, and Academic Achievement in Filipino High School Students.

Science.gov (United States)

Datu, Jesus Alfonso D

2017-04-09

Recent literature has recognized the advantageous role of low-arousal positive affect such as feelings of peacefulness and internal harmony in collectivist cultures. However, limited research has explored the benefits of low-arousal affective states in the educational setting. The current study examined the link of peace of mind (PoM) to academic motivation (i.e., amotivation, controlled motivation, and autonomous motivation) and academic achievement among 525 Filipino high school students. Findings revealed that PoM was positively associated with academic achievement β = .16, p amotivation β = -.19, p < .05, and autonomous motivation was positively associated with academic achievement β = .52, p < .01. Furthermore, the results of bias-corrected bootstrap analyses at 95% confidence interval based on 5,000 bootstrapped resamples demonstrated that peace of mind had an indirect influence on academic achievement through the mediating effects of autonomous motivation. In terms of the effect sizes, the findings showed that PoM explained about 1% to 18% of the variance in academic achievement and motivation. The theoretical and practical implications of the results are elucidated.

Flexible hemispheric microarrays of highly pressure-sensitive sensors based on breath figure method.

Science.gov (United States)

Wang, Zhihui; Zhang, Ling; Liu, Jin; Jiang, Hao; Li, Chunzhong

2018-05-30

Recently, flexible pressure sensors featuring high sensitivity, broad sensing range and real-time detection have aroused great attention owing to their crucial role in the development of artificial intelligent devices and healthcare systems. Herein, highly sensitive pressure sensors based on hemisphere-microarray flexible substrates are fabricated via inversely templating honeycomb structures deriving from a facile and static breath figure process. The interlocked and subtle microstructures greatly improve the sensing characteristics and compressibility of the as-prepared pressure sensor, endowing it a sensitivity as high as 196 kPa-1 and a wide pressure sensing range (0-100 kPa), as well as other superior performance, including a lower detection limit of 0.5 Pa, fast response time (10 000 cycles). Based on the outstanding sensing performance, the potential capability of our pressure sensor in capturing physiological information and recognizing speech signals has been demonstrated, indicating promising application in wearable and intelligent electronics.

pH- and ion-sensitive polymers for drug delivery

Science.gov (United States)

Yoshida, Takayuki; Lai, Tsz Chung; Kwon, Glen S; Sako, Kazuhiro

2013-01-01

Introduction Drug delivery systems (DDSs) are important for effective, safe, and convenient administration of drugs. pH- and ion-responsive polymers have been widely employed in DDS for site-specific drug release due to their abilities to exploit specific pH- or ion-gradients in the human body. Areas covered Having pH-sensitivity, cationic polymers can mask the taste of drugs and release drugs in the stomach by responding to gastric low pH. Anionic polymers responsive to intestinal high pH are used for preventing gastric degradation of drug, colon drug delivery and achieving high bioavailability of weak basic drugs. Tumor-targeted DDSs have been developed based on polymers with imidazole groups or poly(β-amino ester) responsive to tumoral low pH. Polymers with pH-sensitive chemical linkages, such as hydrazone, acetal, ortho ester and vinyl ester, pH-sensitive cell-penetrating peptides and cationic polymers undergoing pH-dependent protonation have been studied to utilize the pH gradient along the endocytic pathway for intracellular drug delivery. As ion-sensitive polymers, ion-exchange resins are frequently used for taste-masking, counterion-responsive drug release and sustained drug release. Polymers responding to ions in the saliva and gastrointestinal fluids are also used for controlled drug release in oral drug formulations. Expert opinion Stimuli-responsive DDSs are important for achieving site-specific and controlled drug release; however, intraindividual, interindividual and intercellular variations of pH should be considered when designing DDSs or drug products. Combination of polymers and other components, and deeper understanding of human physiology are important for development of pH- and ion-sensitive polymeric DDS products for patients. PMID:23930949

pH- and ion-sensitive polymers for drug delivery.

Science.gov (United States)

Yoshida, Takayuki; Lai, Tsz Chung; Kwon, Glen S; Sako, Kazuhiro

2013-11-01

Drug delivery systems (DDSs) are important for effective, safe, and convenient administration of drugs. pH- and ion-responsive polymers have been widely employed in DDS for site-specific drug release due to their abilities to exploit specific pH- or ion-gradients in the human body. Having pH-sensitivity, cationic polymers can mask the taste of drugs and release drugs in the stomach by responding to gastric low pH. Anionic polymers responsive to intestinal high pH are used for preventing gastric degradation of drug, colon drug delivery and achieving high bioavailability of weak basic drugs. Tumor-targeted DDSs have been developed based on polymers with imidazole groups or poly(β-amino ester) responsive to tumoral low pH. Polymers with pH-sensitive chemical linkages, such as hydrazone, acetal, ortho ester and vinyl ester, pH-sensitive cell-penetrating peptides and cationic polymers undergoing pH-dependent protonation have been studied to utilize the pH gradient along the endocytic pathway for intracellular drug delivery. As ion-sensitive polymers, ion-exchange resins are frequently used for taste-masking, counterion-responsive drug release and sustained drug release. Polymers responding to ions in the saliva and gastrointestinal fluids are also used for controlled drug release in oral drug formulations. Stimuli-responsive DDSs are important for achieving site-specific and controlled drug release; however, intraindividual, interindividual and intercellular variations of pH should be considered when designing DDSs or drug products. Combination of polymers and other components, and deeper understanding of human physiology are important for development of pH- and ion-sensitive polymeric DDS products for patients.

Optical Sensitivity of a Monolithic Integrated InP PIN-HEMT-HBT Transimpedance Amplifier

OpenAIRE

Matiss, A.; Janssen, G.; Bertenburg, R. M.; Brockerhoff, W.; Tegude, F.J.

2004-01-01

To improve sensitivity of optical receivers, a special integration concept is chosen that includes a pinphotodiode, high-electron mobility transistors (HEMT) and heterostructure bipolar transistors (HBT) on a single substrate. This work focuses on the optimization of the amplifier design to achieve lowest input noise currents of a transimpedance amplifier, and thus highest receiver sensitivity. The respective advantages of the components used are investigated with respect...

A sensitive zinc-activated 129Xe MRI probe

International Nuclear Information System (INIS)

Kotera, N.; Delacour, L.; Traore, T.; Buisson, D.A.; Taran, F.; Coudert, S.; Rousseau, B.; Tassali, N.; Leonce, E.; Boutin, C.; Berthault, P.; Brotin, T.; Dutasta, J.P.

2012-01-01

Herein we propose the use of hyper-polarized 129 Xe nuclear magnetic resonance (NMR) spectroscopy for the sensitive detection of Zn 2+ ions. To achieve this goal, the noble gas is encapsulated in dedicated host systems bearing a ligand that chelates the Zn 2+ ions. Cryptophanes, aromatic cage molecules made of cyclotriveratrylene groups, are perfectly suited to this purpose as 1) they can easily be rendered water-soluble, 2) the noble gas has a high affinity for their cavity, 3) when xenon is encapsulated, it takes a specific NMR frequency, and 4) xenon exchange in and out of the cavity insures a continuous refreshment of the Xe-cryptophane environment in hyper-polarization. We constructed a powerful 129 Xe NMR-based sensor of Zn 2+ ions, which enables for the first time measurement of Zn 2+ concentrations as low as 100 nm. This high sensitivity was achieved thanks to a smart 129 Xe MRI sensor, where the binding of the ion to the target is accompanied by a change in NMR parameters. We have also demonstrated the importance of working with enantiopure cryptophane derivatives. (O.M.)

Family socioeconomic status, family health, and changes in students' math achievement across high school: A mediational model.

Science.gov (United States)

Barr, Ashley Brooke

2015-09-01

In response to recent calls to integrate understandings of socioeconomic disparities in health with understandings of socioeconomic disparities in academic achievement, this study tested a mediational model whereby family socioeconomic status predicted gains in academic achievement across high school through its impact on both student and parent health. Data on over 8000 high school students in the U.S. were obtained from wave 1 (2009-2010) and wave 2 (2012) of the High School Longitudinal Study of 2009 (HSLS:09), and structural equation modeling with latent difference scores was used to determine the role of family health problems in mediating the well-established link between family SES and gains in academic achievement. Using both static and dynamic indicators of family SES, support was found for this mediational model. Higher family SES in 9th grade reduced the probability of students and their parents experiencing a serious health problem in high school, thereby promoting growth in academic achievement. In addition, parent and student health problems mediated the effect of changes in family SES across high school on math achievement gains. Results emphasize the importance of considering the dynamic nature of SES and that both student and parent health should be considered in understanding SES-related disparities in academic achievement. This relational process provides new mechanisms for understanding the intergenerational transmission of socioeconomic status and the status attainment process more broadly. Copyright © 2015 Elsevier Ltd. All rights reserved.

Plasmodium falciparum transfected with ultra bright NanoLuc luciferase offers high sensitivity detection for the screening of growth and cellular trafficking inhibitors.

Directory of Open Access Journals (Sweden)

Mauro F Azevedo

Full Text Available Drug discovery is a key part of malaria control and eradication strategies, and could benefit from sensitive and affordable assays to quantify parasite growth and to help identify the targets of potential anti-malarial compounds. Bioluminescence, achieved through expression of exogenous luciferases, is a powerful tool that has been applied in studies of several aspects of parasite biology and high throughput growth assays. We have expressed the new reporter NanoLuc (Nluc luciferase in Plasmodium falciparum and showed it is at least 100 times brighter than the commonly used firefly luciferase. Nluc brightness was explored as a means to achieve a growth assay with higher sensitivity and lower cost. In addition we attempted to develop other screening assays that may help interrogate libraries of inhibitory compounds for their mechanism of action. To this end parasites were engineered to express Nluc in the cytoplasm, the parasitophorous vacuole that surrounds the intraerythrocytic parasite or exported to the red blood cell cytosol. As proof-of-concept, these parasites were used to develop functional screening assays for quantifying the effects of Brefeldin A, an inhibitor of protein secretion, and Furosemide, an inhibitor of new permeation pathways used by parasites to acquire plasma nutrients.

Heterogeneity in High Math Achievement across Schools: Evidence from the American Mathematics Competitions. NBER Working Paper No. 18277

Science.gov (United States)

Ellison, Glenn; Swanson, Ashley

2012-01-01

This paper explores differences in the frequency with which students from different schools reach high levels of math achievement. Data from the American Mathematics Competitions is used to produce counts of high-scoring students from more than two thousand public, coeducational, non-magnet, non-charter U.S. high schools. High-achieving students…

A novel nanoprobe for the sensitive detection of Francisella tularensis

Energy Technology Data Exchange (ETDEWEB)

Kim, Ji-eun; Seo, Youngmin; Jeong, Yoon [Department of Bionano Technology, Graduate School, Hanyang University, Seoul 133-791 (Korea, Republic of); Hwang, Mintai P. [Center for Biomaterials, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Hwang, Jangsun [Department of Bionano Technology, Graduate School, Hanyang University, Seoul 133-791 (Korea, Republic of); Choo, Jaebum; Hong, Jong Wook [Department of Bionano Technology, Graduate School, Hanyang University, Seoul 133-791 (Korea, Republic of); Department of Bionano Engineering, Hanyang University ERICA, Ansan 426-791 (Korea, Republic of); Jeon, Jun Ho; Rhie, Gi-eun [Division of High-risk Pathogen Research, Center for Infectious Disease, Korea National Institute of Health, Cheongju 363-951 (Korea, Republic of); Choi, Jonghoon, E-mail: jonghchoi@hanyang.ac.kr [Department of Bionano Technology, Graduate School, Hanyang University, Seoul 133-791 (Korea, Republic of); Department of Bionano Engineering, Hanyang University ERICA, Ansan 426-791 (Korea, Republic of)

2015-11-15

Highlights: • We prepare apoferritin nanoprobes decorated with antibodies and nanoparticles. • We examine nanoprobes for the sensitive detection of Francisella tularensis. • 10-fold decrease of minimum concentration of pathogen was achieved. • Simultaneous detection of multiple high-risk pathogens was obtained. - Abstract: Francisella tularensis is a human zoonotic pathogen and the causative agent of tularemia, a severe infectious disease. Given the extreme infectivity of F. tularensis and its potential to be used as a biological warfare agent, a fast and sensitive detection method is highly desirable. Herein, we construct a novel detection platform composed of two units: (1) Magnetic beads conjugated with multiple capturing antibodies against F. tularensis for its simple and rapid separation and (2) Genetically-engineered apoferritin protein constructs conjugated with multiple quantum dots and a detection antibody against F. tularensis for the amplification of signal. We demonstrate a 10-fold increase in the sensitivity relative to traditional lateral flow devices that utilize enzyme-based detection methods. We ultimately envision the use of our novel nanoprobe detection platform in future applications that require the highly-sensitive on-site detection of high-risk pathogens.

A novel nanoprobe for the sensitive detection of Francisella tularensis

International Nuclear Information System (INIS)

Kim, Ji-eun; Seo, Youngmin; Jeong, Yoon; Hwang, Mintai P.; Hwang, Jangsun; Choo, Jaebum; Hong, Jong Wook; Jeon, Jun Ho; Rhie, Gi-eun; Choi, Jonghoon

2015-01-01

Highlights: • We prepare apoferritin nanoprobes decorated with antibodies and nanoparticles. • We examine nanoprobes for the sensitive detection of Francisella tularensis. • 10-fold decrease of minimum concentration of pathogen was achieved. • Simultaneous detection of multiple high-risk pathogens was obtained. - Abstract: Francisella tularensis is a human zoonotic pathogen and the causative agent of tularemia, a severe infectious disease. Given the extreme infectivity of F. tularensis and its potential to be used as a biological warfare agent, a fast and sensitive detection method is highly desirable. Herein, we construct a novel detection platform composed of two units: (1) Magnetic beads conjugated with multiple capturing antibodies against F. tularensis for its simple and rapid separation and (2) Genetically-engineered apoferritin protein constructs conjugated with multiple quantum dots and a detection antibody against F. tularensis for the amplification of signal. We demonstrate a 10-fold increase in the sensitivity relative to traditional lateral flow devices that utilize enzyme-based detection methods. We ultimately envision the use of our novel nanoprobe detection platform in future applications that require the highly-sensitive on-site detection of high-risk pathogens

The Exploration of the Associations between Locus of Control and High School Students’ Language Achievement

Directory of Open Access Journals (Sweden)

Abbas Eslami-Rasekh

2012-07-01

Full Text Available The purpose of the study is to determine the relationships between locus of control (LOC orientation and high school students’ language achievement. The popular categorization of internals and externals was taken into account. The participants of this study were 121 high school students in the second, third and pre-university grades in two public high schools of Isfahan, Iran. One of the instruments used in the study was an adopted version of Julian Rotters’ locus of control (1966 which identified internal and external orientations. The participants’ English scores were regarded as the measure of their achievement. Besides, a questionnaire consisting of 29 items was administered to all 121 students. Responses were put into one way and two-way ANOVA, the regression analysis, the independent t-test, chi-square and linear regression analysis to compare the means of two sets of scores. The findings of this study show a significant relationship between locus control and achievement of high school students. The findings can be used by EFL teachers and syllabus designers.

Highly sensitive optical chemosensor for the detection of Cu using a ...

Indian Academy of Sciences (India)

Administrator

Highly sensitive colorimetric chemosensor molecule RHN for selective detection of Cu. 2+ in ... colour development against the colourless blank during the sensing event, a feature that would facilitate ... ever reported, much attention has been.

Mesoporous structured MIPs@CDs fluorescence sensor for highly sensitive detection of TNT.

Science.gov (United States)

Xu, Shoufang; Lu, Hongzhi

2016-11-15

A facile strategy was developed to prepare mesoporous structured molecularly imprinted polymers capped carbon dots (M-MIPs@CDs) fluorescence sensor for highly sensitive and selective determination of TNT. The strategy using amino-CDs directly as "functional monomer" for imprinting simplify the imprinting process and provide well recognition sites accessibility. The as-prepared M-MIPs@CDs sensor, using periodic mesoporous silica as imprinting matrix, and amino-CDs directly as "functional monomer", exhibited excellent selectivity and sensitivity toward TNT with detection limit of 17nM. The recycling process was sustainable for 10 times without obvious efficiency decrease. The feasibility of the developed method in real samples was successfully evaluated through the analysis of TNT in soil and water samples with satisfactory recoveries of 88.6-95.7%. The method proposed in this work was proved to be a convenient and practical way to prepare high sensitive and selective fluorescence MIPs@CDs sensors. Copyright © 2016 Elsevier B.V. All rights reserved.

Mathematics Achievement with Digital Game-Based Learning in High School Algebra 1 Classes

Science.gov (United States)

Ferguson, Terri Lynn Kurley

2014-01-01

This study examined the impact of digital game-based learning (DGBL) on mathematics achievement in a rural high school setting in North Carolina. A causal comparative research design was used in this study to collect data to determine the effectiveness of DGBL in high school Algebra 1 classes. Data were collected from the North Carolina…

Subnanometer Ga2O3 tunnelling layer by atomic layer deposition to achieve 1.1 V open-circuit potential in dye-sensitized solar cells.

Science.gov (United States)

Chandiran, Aravind Kumar; Tetreault, Nicolas; Humphry-Baker, Robin; Kessler, Florian; Baranoff, Etienne; Yi, Chenyi; Nazeeruddin, Mohammad Khaja; Grätzel, Michael

2012-08-08

Herein, we present the first use of a gallium oxide tunnelling layer to significantly reduce electron recombination in dye-sensitized solar cells (DSC). The subnanometer coating is achieved using atomic layer deposition (ALD) and leading to a new DSC record open-circuit potential of 1.1 V with state-of-the-art organic D-π-A sensitizer and cobalt redox mediator. After ALD of only a few angstroms of Ga(2)O(3), the electron back reaction is reduced by more than an order of magnitude, while charge collection efficiency and fill factor are increased by 30% and 15%, respectively. The photogenerated exciton separation processes of electron injection into the TiO(2) conduction band and the hole injection into the electrolyte are characterized in detail.

Achieving High-Energy-High-Power Density in a Flexible Quasi-Solid-State Sodium Ion Capacitor.

Science.gov (United States)

Li, Hongsen; Peng, Lele; Zhu, Yue; Zhang, Xiaogang; Yu, Guihua

2016-09-14

Simultaneous integration of high-energy output with high-power delivery is a major challenge for electrochemical energy storage systems, limiting dual fine attributes on a device. We introduce a quasi-solid-state sodium ion capacitor (NIC) based on a battery type urchin-like Na2Ti3O7 anode and a capacitor type peanut shell derived carbon cathode, using a sodium ion conducting gel polymer as electrolyte, achieving high-energy-high-power characteristics in solid state. Energy densities can reach 111.2 Wh kg(-1) at power density of 800 W kg(-1), and 33.2 Wh kg(-1) at power density of 11200 W kg(-1), which are among the best reported state-of-the-art NICs. The designed device also exhibits long-term cycling stability over 3000 cycles with capacity retention ∼86%. Furthermore, we demonstrate the assembly of a highly flexible quasi-solid-state NIC and it shows no obvious capacity loss under different bending conditions.

A wide range and highly sensitive optical fiber pH sensor using polyacrylamide hydrogel

Science.gov (United States)

Pathak, Akhilesh Kumar; Singh, Vinod Kumar

2017-12-01

In the present study we report the fabrication and characterization of no-core fiber sensor (NCFS) using smart hydrogel coating for pH measurement. The no-core fiber (NCF) is stubbed between two single-mode fibers with SMA connector before immobilizing of smart hydrogel. The wavelength interrogation technique is used to calculate the sensitivity of the proposed sensor. The result shows a high sensitivity of 1.94 nm/pH for a wide range of pH values varied from 3 to 10 with a good linear response. In addition to high sensitivity, the fabricated sensor provides a fast response time with a good stability, repeatability and reproducibility.

Analysis of Cyberbullying Sensitivity Levels of High School Students and Their Perceived Social Support Levels

Science.gov (United States)

Akturk, Ahmet Oguz

2015-01-01

Purpose: The purpose of this paper is to determine the cyberbullying sensitivity levels of high school students and their perceived social supports levels, and analyze the variables that predict cyberbullying sensitivity. In addition, whether cyberbullying sensitivity levels and social support levels differed according to gender was also…

High fat diet-fed obese rats are highly sensitive to doxorubicin-induced cardiotoxicity

International Nuclear Information System (INIS)

Mitra, Mayurranjan S.; Donthamsetty, Shashikiran; White, Brent; Mehendale, Harihara M.

2008-01-01

Often, chemotherapy by doxorubicin (Adriamycin) is limited due to life threatening cardiotoxicity in patients during and posttherapy. Recently, we have shown that moderate diet restriction remarkably protects against doxorubicin-induced cardiotoxicity. This cardioprotection is accompanied by decreased cardiac oxidative stress and triglycerides and increased cardiac fatty-acid oxidation, ATP synthesis, and upregulated JAK/STAT3 pathway. In the current study, we investigated whether a physiological intervention by feeding 40% high fat diet (HFD), which induces obesity in male Sprague-Dawley rats (250-275 g), sensitizes to doxorubicin-induced cardiotoxicity. A LD 10 dose (8 mg doxorubicin/kg, ip) administered on day 43 of the HFD feeding regimen led to higher cardiotoxicity, cardiac dysfunction, lipid peroxidation, and 80% mortality in the obese (OB) rats in the absence of any significant renal or hepatic toxicity. Doxorubicin toxicokinetics studies revealed no change in accumulation of doxorubicin and doxorubicinol (toxic metabolite) in the normal diet-fed (ND) and OB hearts. Mechanistic studies revealed that OB rats are sensitized due to: (1) higher oxyradical stress leading to upregulation of uncoupling proteins 2 and 3, (2) downregulation of cardiac peroxisome proliferators activated receptor-α, (3) decreased plasma adiponectin levels, (4) decreased cardiac fatty-acid oxidation (666.9 ± 14.0 nmol/min/g heart in ND versus 400.2 ± 11.8 nmol/min/g heart in OB), (5) decreased mitochondrial AMP-α2 protein kinase, and (6) 86% drop in cardiac ATP levels accompanied by decreased ATP/ADP ratio after doxorubicin administration. Decreased cardiac erythropoietin and increased SOCS3 further downregulated the cardioprotective JAK/STAT3 pathway. In conclusion, HFD-induced obese rats are highly sensitized to doxorubicin-induced cardiotoxicity by substantially downregulating cardiac mitochondrial ATP generation, increasing oxidative stress and downregulating the JAK/STAT3

Environmental Sensitivity in Children: Development of the Highly Sensitive Child Scale and Identification of Sensitivity Groups

Science.gov (United States)

Pluess, Michael; Assary, Elham; Lionetti, Francesca; Lester, Kathryn J.; Krapohl, Eva; Aron, Elaine N.; Aron, Arthur

2018-01-01

A large number of studies document that children differ in the degree they are shaped by their developmental context with some being more sensitive to environmental influences than others. Multiple theories suggest that "Environmental Sensitivity" is a common trait predicting the response to negative as well as positive exposures.…

Capillary Isotachophoresis-Nanoelectrospray Ionization-Selected Reaction Monitoring MS via a Novel Sheathless Interface for High Sensitivity Sample Quantification

Energy Technology Data Exchange (ETDEWEB)

Wang, Chenchen (Chloe); Lee, Cheng S.; Smith, Richard D.; Tang, Keqi

2013-06-21

A novel sheathless CITP/CZE-MS interface featuring a large i.d. separation capillary and a detachable small i.d. ESI emitter was developed in this study to simultaneously achieve large sample loading capacity and stable nanoESI operation. Crucial operating parameters, including sample loading volume, flow rate, and separation window, were systematically investigated to attain optimum CITP/CZE separation efficiency and MS detection sensitivity. The performance of CITP/CZE-nanoESI-MS using the new sheathless interface was evaluated for its achievable low limit of quantitation (LOQ) by analyzing targeted peptides, leu-enkephalin and angiotensin II, spiked in a BSA tryptic digest matrix at different concentrations. A linear dynamic range spanning 4.5 orders of magnitude and a 10 pM LOQ with excellent measurement reproducibility were obtained experimentally for both targeted peptides, representing a 5-fold sensitivity improvement as compared to using the sheath liquid interface developed previously.

Highly vibrationally excited O2 molecules in low-pressure inductively-coupled plasmas detected by high sensitivity ultra-broad-band optical absorption spectroscopy

Science.gov (United States)

Foucher, Mickaël; Marinov, Daniil; Carbone, Emile; Chabert, Pascal; Booth, Jean-Paul

2015-08-01

Inductively-coupled plasmas in pure O2 (at pressures of 5-80 mTorr and radiofrequency power up to 500 W) were studied by optical absorption spectroscopy over the spectral range 200-450 nm, showing the presence of highly vibrationally excited O2 molecules (up to vʺ = 18) by Schumann-Runge band absorption. Analysis of the relative band intensities indicates a vibrational temperature up to 10,000 K, but these hot molecules only represent a fraction of the total O2 density. By analysing the (11-0) band at higher spectral resolution the O2 rotational temperature was also determined, and was found to increase with both pressure and power, reaching 900 K at 80 mTorr 500 W. These measurements were achieved using a new high-sensitivity ultra-broad-band absorption spectroscopy setup, based on a laser-plasma light source, achromatic optics and an aberration-corrected spectrograph. This setup allows the measurement of weak broadband absorbances due to a baseline variability lower than 2   ×   10-5 across a spectral range of 250 nm.

Unforgiving Confucian Culture: A Breeding Ground for High Academic Achievement, Test Anxiety and Self-Doubt?

Science.gov (United States)

Stankov, Lazar

2010-01-01

This paper reviews findings from several studies that contribute to our understanding of cross-cultural differences in academic achievement, anxiety and self-doubt. The focus is on comparisons between Confucian Asian and European regions. Recent studies indicate that high academic achievement of students from Confucian Asian countries is…

High sensitivity tracer imaging of iron oxides using magnetic particle imaging

International Nuclear Information System (INIS)

Goodwill, Patrick; Konkle, Justin; Lu, Kuan; Zheng, Bo; Conolly, Steven

2014-01-01

Full text: Magnetic Particle Imaging (MPI) is a new tracer imaging modality that is gaining significant interest from NMR and MRI researchers. While the physics of MPI differ substantially from MRI, it employs hardware and imaging concepts that are familiar to MRI researchers, such as magnetic excitation and detection, pulse sequences, and relaxation effects. Furthermore, MPI employs the same superparamagnetic iron oxide (SPIO) contrast agents that are sometimes used for MR angiography and are often used for MRI cell tracking studies. These SPIOs are much safer for humans than iodine or gadolinium, especially for Chronic Kidney Disease (CKD) patients. The weak kidneys of CKD patients cannot safely excrete iodine or gadolinium, leading to increased morbidity and mortality after iodinated X-ray or CT angiograms, or after gadolinium-MRA studies. Iron oxides, on the other hand, are processed in the liver, and have been shown to be safe even for CKD patients. Unlike the 'black blood' contrast generated by SPIOs in MRI due to increased T2 dephasing, SPIOs in MPI generate positive, 'bright blood' contrast. With this ideal contrast, even prototype MPI scanners can already achieve fast, high-sensitivity, and high-contrast angiograms with millimeter-scale resolutions in phantoms and in animals. Moreover, MPI shows great potential for an exciting array of applications, including stem cell tracking in vivo, first-pass contrast studies to diagnose or stage cancer, and inflammation imaging in vivo. So far, only a handful of prototype small-animal MPI scanners have been constructed worldwide. Hence, MPI is open to great advances, especially in hardware, pulse sequence, and nanoparticle improvements, with the potential to revolutionize the biomedical imaging field. (author)

High sensitivity tracer imaging of iron oxides using magnetic particle imaging

Energy Technology Data Exchange (ETDEWEB)

Goodwill, Patrick [University of California, Dept. of Bioengineering, Berkeley, CA (United States); Konkle, Justin; Lu, Kuan; Zheng, Bo [UC Berkeley (UCSF), Joint Graduate Group in Bioengineering, CA (United States); Conolly, Steven [University of California, Berkeley Bioengineering, Electrical Engineering, and Computer Science, CA (United States)

2014-07-01

Full text: Magnetic Particle Imaging (MPI) is a new tracer imaging modality that is gaining significant interest from NMR and MRI researchers. While the physics of MPI differ substantially from MRI, it employs hardware and imaging concepts that are familiar to MRI researchers, such as magnetic excitation and detection, pulse sequences, and relaxation effects. Furthermore, MPI employs the same superparamagnetic iron oxide (SPIO) contrast agents that are sometimes used for MR angiography and are often used for MRI cell tracking studies. These SPIOs are much safer for humans than iodine or gadolinium, especially for Chronic Kidney Disease (CKD) patients. The weak kidneys of CKD patients cannot safely excrete iodine or gadolinium, leading to increased morbidity and mortality after iodinated X-ray or CT angiograms, or after gadolinium-MRA studies. Iron oxides, on the other hand, are processed in the liver, and have been shown to be safe even for CKD patients. Unlike the 'black blood' contrast generated by SPIOs in MRI due to increased T2 dephasing, SPIOs in MPI generate positive, 'bright blood' contrast. With this ideal contrast, even prototype MPI scanners can already achieve fast, high-sensitivity, and high-contrast angiograms with millimeter-scale resolutions in phantoms and in animals. Moreover, MPI shows great potential for an exciting array of applications, including stem cell tracking in vivo, first-pass contrast studies to diagnose or stage cancer, and inflammation imaging in vivo. So far, only a handful of prototype small-animal MPI scanners have been constructed worldwide. Hence, MPI is open to great advances, especially in hardware, pulse sequence, and nanoparticle improvements, with the potential to revolutionize the biomedical imaging field. (author)

Closing the Mathematics Achievement Gap in High-Poverty Middle Schools: Enablers and Constraints

Science.gov (United States)

Balfanz, Robert; Byrnes, Vaughan

2006-01-01

The mathematics achievement levels of U.S. students fall far behind those of other developed nations; within the United States itself, the students who are falling behind come predominantly from high-poverty and high-minority areas. This article reports on a series of analyses that followed 4 cohorts of students from 3 such schools through the 5th…

An efficient method of reducing glass dispersion tolerance sensitivity

Science.gov (United States)

Sparrold, Scott W.; Shepard, R. Hamilton

2014-12-01

Constraining the Seidel aberrations of optical surfaces is a common technique for relaxing tolerance sensitivities in the optimization process. We offer an observation that a lens's Abbe number tolerance is directly related to the magnitude by which its longitudinal and transverse color are permitted to vary in production. Based on this observation, we propose a computationally efficient and easy-to-use merit function constraint for relaxing dispersion tolerance sensitivity. Using the relationship between an element's chromatic aberration and dispersion sensitivity, we derive a fundamental limit for lens scale and power that is capable of achieving high production yield for a given performance specification, which provides insight on the point at which lens splitting or melt fitting becomes necessary. The theory is validated by comparing its predictions to a formal tolerance analysis of a Cooke Triplet, and then applied to the design of a 1.5x visible linescan lens to illustrate optimization for reduced dispersion sensitivity. A selection of lenses in high volume production is then used to corroborate the proposed method of dispersion tolerance allocation.

Approaches to achieve high grain yield and high resource use efficiency in rice

Directory of Open Access Journals (Sweden)

Jianchang YANG

2015-06-01

Full Text Available This article discusses approaches to simultaneously increase grain yield and resource use efficiency in rice. Breeding nitrogen efficient cultivars without sacrificing rice yield potential, improving grain fill in later-flowering inferior spikelets and enhancing harvest index are three important approaches to achieving the dual goal of high grain yield and high resource use efficiency. Deeper root distribution and higher leaf photosynthetic N use efficiency at lower N rates could be used as selection criteria to develop N-efficient cultivars. Enhancing sink activity through increasing sugar-spikelet ratio at the heading time and enhancing the conversion efficiency from sucrose to starch though increasing the ratio of abscisic acid to ethylene in grains during grain fill could effectively improve grain fill in inferior spikelets. Several practices, such as post-anthesis controlled soil drying, an alternate wetting and moderate soil drying regime during the whole growing season, and non-flooded straw mulching cultivation, could substantially increase grain yield and water use efficiency, mainly via enhanced remobilization of stored carbon from vegetative tissues to grains and improved harvest index. Further research is needed to understand synergistic interaction between water and N on crop and soil and the mechanism underlying high resource use efficiency in high-yielding rice.

High sensitivity tests of the standard model for electroweak interactions

International Nuclear Information System (INIS)

Koetke, D.D.

1992-01-01

The work done on this project was focussed mainly on LAMPF experiment E969 known as the MEGA experiment, a high sensitivity search for the lepton family number violating decay μ → eγ to a sensitivity which, measured in terms of the branching ratio, BR = [μ→eγ]/[μ→e ν μ ν e ] ∼10 -13 is over two orders of magnitude better than previously reported values. The work done on MEGA during this period was divided between that done at Valparaiso University and that done at LAMPF. In addition, some contributions were made to a proposal to the LAMPF PAC to perform a precision measurement of the Michel ρ parameter, described below

High sensitive quench detection method using an integrated test wire

International Nuclear Information System (INIS)

Fevrier, A.; Tavergnier, J.P.; Nithart, H.; Kiblaire, M.; Duchateau, J.L.

1981-01-01

A high sensitive quench detection method which works even in the presence of an external perturbing magnetic field is reported. The quench signal is obtained from the difference in voltages at the superconducting winding terminals and at the terminals at a secondary winding strongly coupled to the primary. The secondary winding could consist of a ''zero-current strand'' of the superconducting cable not connected to one of the winding terminals or an integrated normal test wire inside the superconducting cable. Experimental results on quench detection obtained by this method are described. It is shown that the integrated test wire method leads to efficient and sensitive quench detection, especially in the presence of an external perturbing magnetic field

A novel detection platform for parallel monitoring of DNA hybridization with high sensitivity and specificity

DEFF Research Database (Denmark)

Yi, Sun; Perch-Nielsen, Ivan R.; Wang, Zhenyu

We developed a high-sensitive platform to monior multiple hybridization events in real time. By creating a microoptical array in a polymeric chip, the system combine the excellent discriminative power of supercritical angle fluorescence (SAF) microscopy with high-throughput capabilities of microa......We developed a high-sensitive platform to monior multiple hybridization events in real time. By creating a microoptical array in a polymeric chip, the system combine the excellent discriminative power of supercritical angle fluorescence (SAF) microscopy with high-throughput capabilities...

Rats bred for high alcohol drinking are more sensitive to delayed and probabilistic outcomes.

Science.gov (United States)

Wilhelm, C J; Mitchell, S H

2008-10-01

Alcoholics and heavy drinkers score higher on measures of impulsivity than nonalcoholics and light drinkers. This may be because of factors that predate drug exposure (e.g. genetics). This study examined the role of genetics by comparing impulsivity measures in ethanol-naive rats selectively bred based on their high [high alcohol drinking (HAD)] or low [low alcohol drinking (LAD)] consumption of ethanol. Replicates 1 and 2 of the HAD and LAD rats, developed by the University of Indiana Alcohol Research Center, completed two different discounting tasks. Delay discounting examines sensitivity to rewards that are delayed in time and is commonly used to assess 'choice' impulsivity. Probability discounting examines sensitivity to the uncertain delivery of rewards and has been used to assess risk taking and risk assessment. High alcohol drinking rats discounted delayed and probabilistic rewards more steeply than LAD rats. Discount rates associated with probabilistic and delayed rewards were weakly correlated, while bias was strongly correlated with discount rate in both delay and probability discounting. The results suggest that selective breeding for high alcohol consumption selects for animals that are more sensitive to delayed and probabilistic outcomes. Sensitivity to delayed or probabilistic outcomes may be predictive of future drinking in genetically predisposed individuals.

Network single-walled carbon nanotube biosensors for fast and highly sensitive detection of proteins

International Nuclear Information System (INIS)

Hu Pingan; Zhang Jia; Wen Zhenzhong; Zhang Can

2011-01-01

Detection of proteins is powerfully assayed in the diagnosis of diseases. A strategy for the development of an ultrahigh sensitivity biosensor based on a network single-walled carbon nanotube (SWNT) field-effect transistor (FET) has been demonstrated. Metallic SWNTs (m-SWNTs) in the network nanotube FET were selectively removed or cut via a carefully controlled procedure of electrical break-down (BD), and left non-conducting m-SWNTs which magnified the Schottky barrier (SB) area. This nanotube FET exhibited ultrahigh sensitivity and fast response to biomolecules. The lowest detection limit of 0.5 pM was achieved by exploiting streptavidin (SA) or a biotin/SA pair as the research model, and BD-treated nanotube biosensors had a 2 x 10 4 -fold lower minimum detectable concentration than the device without BD treatment. The response time is in the range of 0.3-3 min.

Development of a high sensitivity pinhole type gamma camera using semiconductors for low dose rate fields

Science.gov (United States)

Ueno, Yuichiro; Takahashi, Isao; Ishitsu, Takafumi; Tadokoro, Takahiro; Okada, Koichi; Nagumo, Yasushi; Fujishima, Yasutake; Yoshida, Akira; Umegaki, Kikuo

2018-06-01

We developed a pinhole type gamma camera, using a compact detector module of a pixelated CdTe semiconductor, which has suitable sensitivity and quantitative accuracy for low dose rate fields. In order to improve the sensitivity of the pinhole type semiconductor gamma camera, we adopted three methods: a signal processing method to set the discriminating level lower, a high sensitivity pinhole collimator and a smoothing image filter that improves the efficiency of the source identification. We tested basic performances of the developed gamma camera and carefully examined effects of the three methods. From the sensitivity test, we found that the effective sensitivity was about 21 times higher than that of the gamma camera for high dose rate fields which we had previously developed. We confirmed that the gamma camera had sufficient sensitivity and high quantitative accuracy; for example, a weak hot spot (0.9 μSv/h) around a tree root could be detected within 45 min in a low dose rate field test, and errors of measured dose rates with point sources were less than 7% in a dose rate accuracy test.

High-Efficiency Dye-Sensitized Solar Cell with Three-Dimensional Photoanode

KAUST Repository

Tétreault, Nicolas

2011-11-09

Herein, we present a straightforward bottom-up synthesis of a high electron mobility and highly light scattering macroporous photoanode for dye-sensitized solar cells. The dense three-dimensional Al/ZnO, SnO2, or TiO 2 host integrates a conformal passivation thin film to reduce recombination and a large surface-area mesoporous anatase guest for high dye loading. This novel photoanode is designed to improve the charge extraction resulting in higher fill factor and photovoltage for DSCs. An increase in photovoltage of up to 110 mV over state-of-the-art DSC is demonstrated. © 2011 American Chemical Society.

High-Efficiency Dye-Sensitized Solar Cell with Three-Dimensional Photoanode

KAUST Repository

Té treault, Nicolas; Arsenault, É ric; Heiniger, Leo-Philipp; Soheilnia, Navid; Brillet, Jé ré mie; Moehl, Thomas; Zakeeruddin, Shaik; Ozin, Geoffrey A.; Grä tzel, Michael

2011-01-01

Herein, we present a straightforward bottom-up synthesis of a high electron mobility and highly light scattering macroporous photoanode for dye-sensitized solar cells. The dense three-dimensional Al/ZnO, SnO2, or TiO 2 host integrates a conformal passivation thin film to reduce recombination and a large surface-area mesoporous anatase guest for high dye loading. This novel photoanode is designed to improve the charge extraction resulting in higher fill factor and photovoltage for DSCs. An increase in photovoltage of up to 110 mV over state-of-the-art DSC is demonstrated. © 2011 American Chemical Society.

BH5047 type depth sand moisture-meter of high sensitivity

International Nuclear Information System (INIS)

Ji Changsong; Xie Liangnian; Zhang Shulan; Zhang Shuheng

2000-01-01

A new depth neutron moisture meter BH5047 has been developed. BH5047 neutron moisture meter is characterised by it is high sensitivity and used for sand water content measurement at concrete mixer. Calibration function is obtained by the Method of Least Squares. Linear correlation efficiency is as good as 0.9977

Intra-Cavity Total Reflection For High Sensitivity Measurement Of Optical Properties

Science.gov (United States)

Pipino, Andrew Charles Rule

1999-11-16

An optical cavity resonator device is provided for conducting sensitive murement of optical absorption by matter in any state with diffraction-limited spatial resolution through utilization of total internal reflection within a high-Q (high quality, low loss) optical cavity. Intracavity total reflection generates an evanescent wave that decays exponentially in space at a point external to the cavity, thereby providing a localized region where absorbing materials can be sensitively probed through alteration of the Q-factor of the otherwise isolated cavity. When a laser pulse is injected into the cavity and passes through the evanescent state, an amplitude loss resulting from absorption is incurred that reduces the lifetime of the pulse in the cavity. By monitoring the decay of the injected pulse, the absorption coefficient of manner within the evanescent wave region is accurately obtained from the decay time measurement.

Charge Transfer Dynamics of Highly Efficient Cyanidin-3-O- Glucoside Sensitizer for Dye-Sensitized Solar Cells

International Nuclear Information System (INIS)

Prima, E C; Yuliarto, B; Suyatman; Dipojono, H K

2016-01-01

This paper reports the novel efficiency achievement of black rice-based natural dye- sensitized solar cells. The higher dye concentration, the longer dye extraction as well as dye immersion onto a TiO 2 film, and the co-adsorption addition are key strategies for improved-cell performance compared to the highest previous achievement. The black rice dye containing 1.38 mM cyanidin-3-O-glucoside has been extracted without purification for 3 weeks at dark condition and room temperature. The anatase TiO 2 photoanode was dipped into dye solution within 4 days. Its electrode was firmly sealed to be a cell and was filled by I - /I 3 - electrolyte using vacuum technique. As a result, the overall solar-to-energy conversion efficiency was 1.49% at AM 1.5 illumination (100 mW.cm -2 ). The voltametric analysis has reported the interfacial electronic band edges of TiO 2 -Dye-Electrolyte. Furthermore, electrochemical impedance spectroscopy has shown the kinetic of interfacial electron transfer dynamics among TiO 2 -dye-electrolyte. The cell has the transfer resistance (Rt) of 12.5 ω, the recombination resistance (Rr) of 266.8 ω, effective electron diffusion coefficients (Dn) of 1.4 × 10 -3 cm 2 /s, Dye-TiO 2 effective electron transfer (τ d ) of 26.6 μs, effective diffusion length (L n )of 33.78 μm, chemical capacitance (C μ ) of 12.43 μF, and electron lifetime (τ n ) of 3.32 ms. (paper)

Spin-torque diode with tunable sensitivity and bandwidth by out-of-plane magnetic field

Energy Technology Data Exchange (ETDEWEB)

Li, X.; Zheng, C.; Pong, Philip W. T. [Department of Electrical and Electronic Engineering, The University of Hong Kong (Hong Kong); Zhou, Y., E-mail: yanzhou@hku.hk [School of Electronics Science and Engineering, Nanjing University, Nanjing 210093 (China); Department of Physics, The University of Hong Kong (Hong Kong); Kubota, H.; Yuasa, S. [Spintronics Research Center, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8568 (Japan)

2016-06-06

Spin-torque diodes based on nanosized magnetic tunnel junctions are novel microwave detectors with high sensitivity and wide frequency bandwidth. While previous reports mainly focus on improving the sensitivity, the approaches to extend the bandwidth are limited. This work experimentally demonstrates that through optimizing the orientation of the external magnetic field, wide bandwidth can be achieved while maintaining high sensitivity. The mechanism of the frequency- and sensitivity-tuning is investigated through analyzing the dependence of resonant frequency and DC voltage on the magnitude and the tilt angle of hard-plane magnetic field. The frequency dependence is qualitatively explicated by Kittel's ferromagnetic resonance model. The asymmetric resonant frequency at positive and negative magnetic field is verified by the numerical simulation considering the in-plane anisotropy. The DC voltage dependence is interpreted through evaluating the misalignment angle between the magnetization of the free layer and the reference layer. The tunability of the detector performance by the magnetic field angle is evaluated through characterizing the sensitivity and bandwidth under 3D magnetic field. The frequency bandwidth up to 9.8 GHz or maximum sensitivity up to 154 mV/mW (after impedance mismatch correction) can be achieved by tuning the angle of the applied magnetic field. The results show that the bandwidth and sensitivity can be controlled and adjusted through optimizing the orientation of the magnetic field for various applications and requirements.

Waterproof Electronic-Bandage with Tunable Sensitivity for Wearable Strain Sensors.

Science.gov (United States)

Jeon, Jun-Young; Ha, Tae-Jun

2016-02-03

We demonstrate high-performance wearable electronic-bandage (E-bandage) based on carbon nanotube (CNT)/silver nanoparticle (AgNP) composites covered with flexible media of fluoropolymer-coated polydimethylsiloxane (PDMS) films. The E-bandage can be used for motion-related sensors by directly attaching them to human skin, which achieves a fast and accurate electric response with high sensitivity according to the bending and stretching movements that induce changes in the conductivity. This advance in the E-bandage is realized as a result of the sensitivity that can be achieved by controlling the concentration of AgNPs in CNT pastes and by modifying the device architecture. The fluoropolymer encapsulation with hydrophobic surface characteristics allows for the E-bandage to operate in water and protects it from physical and chemical contact with the daily life conditions of the human skin. The reliability and scalability of the E-bandage as well as the compatibility with conventional microfabrication allow new possibilities to integrate flexible human-interactive nanoelectronics into mobile health-care monitoring systems combined with Internet of things (IoTs).

Sensitive determination of D-lactic acid and L-lactic acid in urine by high-performance liquid chromatography-tandem mass spectrometry.

Science.gov (United States)

Henry, H; Marmy Conus, N; Steenhout, P; Béguin, A; Boulat, O

2012-04-01

D-lactic acid in urine originates mainly from bacterial production in the intestinal tract. Increased D-lactate excretion as observed in patients affected by short bowel syndrome or necrotizing enterocolitis reflects D-lactic overproduction. Therefore, there is a need for a reliable and sensitive method able to detect D-lactic acid even at subclinical elevation levels. A new and highly sensitive method for the simultaneous determination of L- and D-lactic acid by a two-step procedure has been developed. This method is based on the concentration of lactic acid enantiomers from urine by supported liquid extraction followed by high-performance liquid chromatography-tandem mass spectrometry. The separation was achieved by the use of an Astec Chirobiotic™ R chiral column under isocratic conditions. The calibration curves were linear over the ranges of 2-400 and 0.5-100 µmol/L respectively for L- and D-lactic acid. The limit of detection of D-lactic acid was 0.125 µmol/L and its limit of quantification was 0.5 µmol/L. The overall accuracy and precision were well within 10% of the nominal values. The developed method is suitable for production of reference values in children and could be applied for accurate routine analysis. Copyright © 2011 John Wiley & Sons, Ltd.

Sensitivity of MENA Tropical Rainbelt to Dust Shortwave Absorption: A High Resolution AGCM Experiment

KAUST Repository

Bangalath, Hamza Kunhu; Stenchikov, Georgiy L.

2016-01-01

Shortwave absorption is one of the most important, but the most uncertain, components of direct radiative effect by mineral dust. It has a broad range of estimates from different observational and modeling studies and there is no consensus on the strength of absorption. To elucidate the sensitivity of the Middle East and North Africa (MENA) tropical summer rainbelt to a plausible range of uncertainty in dust shortwave absorption, AMIP-style global high resolution (25 km) simulations are conducted with and without dust, using the High-Resolution Atmospheric Model (HiRAM). Simulations with dust comprise three different cases by assuming dust as a very efficient, standard and inefficient absorber. Inter-comparison of these simulations shows that the response of the MENA tropical rainbelt is extremely sensitive to the strength of shortwave absorption. Further analyses reveal that the sensitivity of the rainbelt stems from the sensitivity of the multi-scale circulations that define the rainbelt. The maximum response and sensitivity are predicted over the northern edge of the rainbelt, geographically over Sahel. The sensitivity of the responses over the Sahel, especially that of precipitation, is comparable to the mean state. Locally, the response in precipitation reaches up to 50% of the mean, while dust is assumed to be a very efficient absorber. Taking into account that Sahel has a very high climate variability and is extremely vulnerable to changes in precipitation, the present study suggests the importance of reducing uncertainty in dust shortwave absorption for a better simulation and interpretation of the Sahel climate.

Sensitivity of MENA Tropical Rainbelt to Dust Shortwave Absorption: A High Resolution AGCM Experiment

KAUST Repository

Bangalath, Hamza Kunhu

2016-06-13

Shortwave absorption is one of the most important, but the most uncertain, components of direct radiative effect by mineral dust. It has a broad range of estimates from different observational and modeling studies and there is no consensus on the strength of absorption. To elucidate the sensitivity of the Middle East and North Africa (MENA) tropical summer rainbelt to a plausible range of uncertainty in dust shortwave absorption, AMIP-style global high resolution (25 km) simulations are conducted with and without dust, using the High-Resolution Atmospheric Model (HiRAM). Simulations with dust comprise three different cases by assuming dust as a very efficient, standard and inefficient absorber. Inter-comparison of these simulations shows that the response of the MENA tropical rainbelt is extremely sensitive to the strength of shortwave absorption. Further analyses reveal that the sensitivity of the rainbelt stems from the sensitivity of the multi-scale circulations that define the rainbelt. The maximum response and sensitivity are predicted over the northern edge of the rainbelt, geographically over Sahel. The sensitivity of the responses over the Sahel, especially that of precipitation, is comparable to the mean state. Locally, the response in precipitation reaches up to 50% of the mean, while dust is assumed to be a very efficient absorber. Taking into account that Sahel has a very high climate variability and is extremely vulnerable to changes in precipitation, the present study suggests the importance of reducing uncertainty in dust shortwave absorption for a better simulation and interpretation of the Sahel climate.

Subnanometer Ga 2 O 3 Tunnelling Layer by Atomic Layer Deposition to Achieve 1.1 V Open-Circuit Potential in Dye-Sensitized Solar Cells

KAUST Repository

Chandiran, Aravind Kumar

2012-08-08

Herein, we present the first use of a gallium oxide tunnelling layer to significantly reduce electron recombination in dye-sensitized solar cells (DSC). The subnanometer coating is achieved using atomic layer deposition (ALD) and leading to a new DSC record open-circuit potential of 1.1 V with state-of-the-art organic D-π-A sensitizer and cobalt redox mediator. After ALD of only a few angstroms of Ga 2O 3, the electron back reaction is reduced by more than an order of magnitude, while charge collection efficiency and fill factor are increased by 30% and 15%, respectively. The photogenerated exciton separation processes of electron injection into the TiO 2 conduction band and the hole injection into the electrolyte are characterized in detail. © 2012 American Chemical Society.

Development of an ozone high sensitive sensor working at ambient temperature

International Nuclear Information System (INIS)

Berger, F; Ghaddab, B; Sanchez, J B; Mavon, C

2011-01-01

Hybrid SnO 2 /SWNTs thin layer were deposited by using sol-gel process. Such sensitive layers showed very high performances for O 3 flow detection at ambient temperature. Limit sensitivity, lower than 21,5 ppb of O 3 in air has been reached by using these hybrid layers. Compared to usefull metal oxide sensors, the main advantage of the use of such hybrid layers, is that these devices enable the detection of O 3 traces at room temperature. The influence of sensor's working temperature is discussed and finally a reactional mechanism for the detection of O 3 is proposed.

Means of achieving high load factors at Olkiluoto 1 and 2

International Nuclear Information System (INIS)

Patrakka, E.

2001-01-01

Teollisuuden Voima Oy operates two BWR units Olkiluoto 1 and 2 that have achieved load factors typically higher than 90%. The operating experiences gained in the 1990s is summarised and the factors contributing to the high capacity factors are addressed. These include the general objectives for operation and maintenance, plant modernisation programme, maintenance principles, and outage policy and experiences. Finally, the international evaluations performed at Olkiluoto are mentioned. (author)

Perfectionism in High-Ability Students: Relational Precursors and Influences on Achievement Motivation

Science.gov (United States)

Speirs Neumeister, Kristie L.; Finch, Holmes

2006-01-01

The purpose of the present study was to create and test a model that (a) illustrated variables influencing the development of perfectionism, and (b) demonstrated how different types of perfectionism may influence the achievement goals of high-ability students. Using a multiple groups path analysis, the researchers found that parenting style was…

Academic Identity Status, Goal Orientation, and Academic Achievement among High School Students

Science.gov (United States)

Hejazi, Elaheh; Lavasani, Masoud Gholamali; Amani, Habib; Was, Christopher A.

2012-01-01

The aim of the present study was to determine the relationship between academic identity status, goal orientations and academic achievement. 301 first year high school students completed the Academic Identity Measure and Goal Orientation Questionnaire. The average of 10 exam scores in the final semester was used as an index of academic…

Highly sensitive detection of the PIK3CAH1047R mutation in colorectal cancer using a novel PCR-RFLP method

International Nuclear Information System (INIS)

Li, Wan-Ming; Hu, Ting-Ting; Zhou, Lin-Lin; Feng, Yi-Ming; Wang, Yun-Yi; Fang, Jin

2016-01-01

The PIK3CA H1047R mutation is considered to be a potential predictive biomarker for EGFR-targeted therapies. In this study, we developed a novel PCR-PFLP approach to detect the PIK3CA H1047R mutation in high effectiveness. A 126-bp fragment of PIK3CA exon-20 was amplified by PCR, digested with FspI restriction endonuclease and separated by 3 % agarose gel electrophoresis for the PCR-RFLP analysis. The mutant sequence of the PIK3CA H1047R was spiked into the corresponding wild-type sequence in decreasing ratios for sensitivity analysis. Eight-six cases of formalin-fixed paraffin-embedded colorectal cancer (CRC) specimens were subjected to PCR-RFLP to evaluate the applicability of the method. The PCR-RFLP method had a capability to detect as litter as 0.4 % of mutation, and revealed 16.3 % of the PIK3CA H1047R mutation in 86 CRC tissues, which was significantly higher than that discovered by DNA sequencing (9.3 %). A positive association between the PIK3CA H1047R mutation and the patients’ age was first found, except for the negative relationship with the degree of tumor differentiation. In addition, the highly sensitive detection of a combinatorial mutation of PIK3CA, KRAS and BRAF was achieved using individual PCR-RFLP methods. We developed a sensitive, simple and rapid approach to detect the low-abundance PIK3CA H1047R mutation in real CRC specimens, providing an effective tool for guiding cancer targeted therapy

Achievement Emotions as Predictors of High School Science Success Among African-American and European American Students

Science.gov (United States)

Bowe, Marilyn Louise Simmons

The literature includes few studies of the interrelations of achievement goals and achievement emotions with respect to minority students and science achievement. The objective of this study was to test the control-value theory (CVT) of achievement emotions to determine if the eight discrete achievement emotions would be predictive of test scores on the High School Graduation Test (GHSGT)-Science for African-American compared to European-American science students. Convenience cluster sampling was employed to select 160 students who were all juniors in the same public high school at the time that they took the GHSGT-Science. The central research question for this study aimed to uncover whether any of the eight achievement emotions identified in CVT would contribute significantly to the predictability of science achievement as measured by GHSGT-Science scores. Data were collected using a nonexperimental, cross sectional design survey. Data were analyzed using a hierarchal, forced entry, multiple regression analysis. Key results indicated that the eight achievement emotions were predictive of GHSGT-Science score outcomes. Positive social change at the individual level could reflect a boost in confidence for African American science students and help decrease the achievement gap in science, technology, engineering, and mathematics (STEM) endeavors between European Americans and African-American students. Educators may consider the importance of achievement emotions in science outcomes by including social emotional learning (SEL) as a part of the regular science curriculum. Future researchers should repeat the study in a school district where the population is available to support the desired cluster sample of equal parts European Americans to African Americans and male to female students.

High sensitivity tests of the standard model for electroweak interactions

International Nuclear Information System (INIS)

Koetke, D.D.; Manweiler, R.W.; Shirvel Stanislaus, T.D.

1993-01-01

The work done on this project was focused on two LAMPF experiments. The MEGA experiment, a high-sensitivity search for the lepton-family-number-violating decay μ → e γ to a sensitivity which, measured in terms of the branching ratio, BR = [μ → e γ]/[μ → ev μ v e ] ∼ 10 -13 , is over two orders of magnitude better than previously reported values. The second is a precision measurement of the Michel ρ parameter from the positron energy spectrum of μ → ev μ v e to test the V-A theory of weak interactions. The uncertainty in the measurement of the Michel ρ parameter is expected to be a factor of three lower than the present reported value

Ad-Me: A Context-Sensitive Advertising System

OpenAIRE

Hristova, Nataliya; O'Hare, G. M. P. (Greg M. P.)

2001-01-01

The mobile commerce sector and in particular the context sensitive advertising will represent a high yield revenue stream. This paper introduces the Ad-me (Advertising for the Mobile E-commerce user) system. The Ad-me is a mobile tourist guide that proactively delivers advertisements to users based upon perceived individual user needs together with their location. A Multi-Agent Systems (MAS) design philosophy is adopted. In order to achieve maximum content diffusion a range of presentation...

Highly sensitive chemiluminescent point mutation detection by circular strand-displacement amplification reaction.

Science.gov (United States)

Shi, Chao; Ge, Yujie; Gu, Hongxi; Ma, Cuiping

2011-08-15

Single nucleotide polymorphism (SNP) genotyping is attracting extensive attentions owing to its direct connections with human diseases including cancers. Here, we have developed a highly sensitive chemiluminescence biosensor based on circular strand-displacement amplification and the separation by magnetic beads reducing the background signal for point mutation detection at room temperature. This method took advantage of both the T4 DNA ligase recognizing single-base mismatch with high selectivity and the strand-displacement reaction of polymerase to perform signal amplification. The detection limit of this method was 1.3 × 10(-16)M, which showed better sensitivity than that of most of those reported detection methods of SNP. Additionally, the magnetic beads as carrier of immobility was not only to reduce the background signal, but also may have potential apply in high through-put screening of SNP detection in human genome. Copyright © 2011 Elsevier B.V. All rights reserved.

A highly sensitive pressure sensor using a Au-patterned polydimethylsiloxane membrane for biosensing applications

International Nuclear Information System (INIS)

Liu, Xinchuan; Zhu, Yihao; Nomani, Md W; Koley, Goutam; Wen, Xuejun; Hsia, Tain-Yen

2013-01-01

We report on the fabrication and characterization of a highly sensitive pressure sensor using a Au film patterned on a polydimethylsiloxane (PDMS) membrane. The strain-induced change in the film resistance was utilized to perform the quantitative measurement of absolute pressure. The highest sensitivity obtained for a 200 µm thick PDMS film sensor was 0.23/KPa with a range of 50 mm Hg, which is the best result reported so far, over that range, for any pressure sensor on a flexible membrane. The noise-limited pressure resolution was found to be 0.9 Pa (0.007 mm Hg), and a response time of ∼200 ms, are the best reported results for these sensors. The ultrahigh sensitivity is attributed to the strain-induced formation of microcracks, the effect of which on the resistance change was found to be highly reversible within a certain pressure range. A physical model correlating the sensitivity with the sensor parameters and crack geometry has been proposed. (paper)

High-sensitivity visualization of localized electric fields using low-energy electron beam deflection

Science.gov (United States)

Jeong, Samuel; Ito, Yoshikazu; Edwards, Gary; Fujita, Jun-ichi

2018-06-01

The visualization of localized electronic charges on nanocatalysts is expected to yield fundamental information about catalytic reaction mechanisms. We have developed a high-sensitivity detection technique for the visualization of localized charges on a catalyst and their corresponding electric field distribution, using a low-energy beam of 1 to 5 keV electrons and a high-sensitivity scanning transmission electron microscope (STEM) detector. The highest sensitivity for visualizing a localized electric field was ∼0.08 V/µm at a distance of ∼17 µm from a localized charge at 1 keV of the primary electron energy, and a weak local electric field produced by 200 electrons accumulated on the carbon nanotube (CNT) apex can be visualized. We also observed that Au nanoparticles distributed on a CNT forest tended to accumulate a certain amount of charges, about 150 electrons, at a ‑2 V bias.

Resistance risk assessment within herbicide authorisation--a call for sensitivity data.

Science.gov (United States)

Ulber, Lena; Nordmeyer, Henning; Zwerger, Peter

2013-02-01

In most European countries, the risk of herbicide resistance is assessed as part of the authorisation of herbicides in accordance with EPPO Standard PP 1/213(2). Because the susceptibility of weed populations to a certain herbicide may vary greatly, one part of resistance risk assessment is the testing for sensitivity variation among different populations of target weed species with a high resistance risk. This paper emphasises the importance of sensitivity data provision with regard to the recent EU Regulation (EC) 1107/2009 concerning the placing of plant protection products on the market and outlines the main technical requirements for sensitivity data. A useful principle is that sensitivity data should be provided for all herbicides with a high resistance risk regardless of whether resistance has already evolved against the herbicidal substance. Methodical details regarding the generation of sensitivity data are discussed, together with remaining questions that will need to be addressed if a harmonised assessment of herbicide resistance risk is to be achieved. Copyright © 2012 Society of Chemical Industry.

Transportable high sensitivity small sample radiometric calorimeter

International Nuclear Information System (INIS)

Wetzel, J.R.; Biddle, R.S.; Cordova, B.S.; Sampson, T.E.; Dye, H.R.; McDow, J.G.

1998-01-01

A new small-sample, high-sensitivity transportable radiometric calorimeter, which can be operated in different modes, contains an electrical calibration method, and can be used to develop secondary standards, will be described in this presentation. The data taken from preliminary tests will be presented to indicate the precision and accuracy of the instrument. The calorimeter and temperature-controlled bath, at present, require only a 30-in. by 20-in. tabletop area. The calorimeter is operated from a laptop computer system using unique measurement module capable of monitoring all necessary calorimeter signals. The calorimeter can be operated in the normal calorimeter equilibration mode, as a comparison instrument, using twin chambers and an external electrical calibration method. The sample chamber is 0.75 in (1.9 cm) in diameter by 2.5 in. (6.35 cm) long. This size will accommodate most 238 Pu heat standards manufactured in the past. The power range runs from 0.001 W to <20 W. The high end is only limited by sample size

A highly uniform ZnO/NaTaO3 nanocomposite: Enhanced self-sensitized degradation of colored pollutants under visible light

International Nuclear Information System (INIS)

Xing, Guanjie; Tang, Changhe; Zhang, Bo; Zhao, Lanxiao; Su, Yiguo; Wang, Xiaojing

2015-01-01

In this study, a highly uniform ZnO/NaTaO 3 composite was prepared via simple hydrothermal synthesis. XRD confirmed the composite was constructed by pure cubic phase of NaTaO 3 and hexagonal phase of ZnO. SEM analysis showed that as-prepared ZnO/NaTaO 3 shaped as an irregular ginger with an obviously smaller size than that of pure ZnO without obvious agglomeration. EDS mapping demonstrated that the four elements (Na, Ta, O, Zn) in the composite were very uniformly distributed. The photocatalytic behaviors of as-prepared composites were studied in the degradation of methylene blue both under UV and visible irradiation. The bare ZnO showed the highest activity with 99.8% methylene blue (MB) photodegraded in 70 min under UV light irradiation whereas 94% photodegraded rate was achieved for ZnO/NaTaO 3 . More importantly, the uniform composite of ZnO/NaTaO 3 exhibited effective degradation of methylene blue under visible light which can be attributed to the well dyes adsorption abilities and the high efficiency of electron separation, induced by the synergistic effect between ZnO and NaTaO 3 . It is confirmed the dye rather than a semiconductor is excited under visible light irradiation and a self-sensitized photocatalytic mechanism was then proposed based on the experimental results. - Graphical abstract: Visible light photocatalytic activity of ZnO/NaTaO 3 and proposed schematic of self-sensitization directed photogradation of MB. - Highlights: • Highly uniform ZnO/NaTaO 3 photocatalysts were fabricated by hydrothermal method. • ZnO/NaTaO 3 composite exhibited effective degradation of MB under visible light. • ZnO/NaTaO 3 composite effectively promoted dye adsorption and electrons separation. • A self-sensitized photocatalytic mechanism was proposed for the degradation of dye

High sensitivity on-line monitor for radioactive effluent

Energy Technology Data Exchange (ETDEWEB)

Sasaki, Toshimi [Tohoku Electric Power Co. Ltd., Sendai (Japan); Ishizuka, Akira; Abe, Eisuke; Inoue, Yasuhiko; Fujii, Masaaki; Kitaguchi, Hiroshi; Doi, Akira

1983-04-01

A new approach for a highly sensitive effluent monitor is presented. The free flow type monitor, which consists of a straightener, nozzle, monitoring section and ..gamma..-ray detector, is demonstrated to be effective in providing long term stability. The 160 start-and-stop cycles of effluent discharge were repeated in a 120-h testing period. Results showed a background increase was not observed for the free flow type monitor. The background count rate was calibrated to the lowest detection limit to be 2.2 x 10/sup -2/ Bq/ml for a 300 s measurement time.

Addressing Curse of Dimensionality in Sensitivity Analysis: How Can We Handle High-Dimensional Problems?

Science.gov (United States)

Safaei, S.; Haghnegahdar, A.; Razavi, S.

2016-12-01

Complex environmental models are now the primary tool to inform decision makers for the current or future management of environmental resources under the climate and environmental changes. These complex models often contain a large number of parameters that need to be determined by a computationally intensive calibration procedure. Sensitivity analysis (SA) is a very useful tool that not only allows for understanding the model behavior, but also helps in reducing the number of calibration parameters by identifying unimportant ones. The issue is that most global sensitivity techniques are highly computationally demanding themselves for generating robust and stable sensitivity metrics over the entire model response surface. Recently, a novel global sensitivity analysis method, Variogram Analysis of Response Surfaces (VARS), is introduced that can efficiently provide a comprehensive assessment of global sensitivity using the Variogram concept. In this work, we aim to evaluate the effectiveness of this highly efficient GSA method in saving computational burden, when applied to systems with extra-large number of input factors ( 100). We use a test function and a hydrological modelling case study to demonstrate the capability of VARS method in reducing problem dimensionality by identifying important vs unimportant input factors.

A highly sensitive multiplasmonic sensor using hyperbolic chiral sculptured thin films

Science.gov (United States)

Abbas, Farhat; Faryad, Muhammad

2017-11-01

Surface plasmon-polariton (SPP) waves guided by an interface of a metal and a hyperbolic chiral sculptured thin film (STF) were theoretically investigated for optical sensing of an analyte. The chiral STF was infiltrated with the analyte to be sensed, and the resulting change in the incidence angle of excitation of the SPP waves in the prism-coupled configuration was computed. The results indicated the potential of this configuration for a plasmonic sensor with sensitivity up to 6000 degrees per refractive index units of the infiltrating fluid in the angular investigation scheme, with multiple SPP waves of the same frequency but different phase speeds, spatial profiles, and sensitivities. The enhancement in the sensitivity is attributed to the high field strength of the SPP waves near the interface. A multiplasmonic sensor is advantageous because of its potential for higher confidence in the measurement of the same analyte.

The Impact of High School Exit Exams on Graduation Rates and Achievement

Science.gov (United States)

Caves, Katherine; Balestra, Simone

2018-01-01

The authors examined the short- and long-term effects of high school exit exams (HSEEs) on graduation rates and achievement using an interrupted time series approach. There is a positive overall effect of HSEE introduction for graduation rate trends, which is heterogeneous over time. HSEEs have a negative impact on graduation rates in the year of…

Family Processes Affect Students' Motivation, and Science and Math Achievement in Cypriot High Schools.

Science.gov (United States)

Koutsoulis, Michalis K.; Campbell, James Reed

2001-01-01

Studied the influence of home environment on male and female high school students' motivation and achievement. Results for 737 Cypriot high school students and their parents show the importance of student self-concept and negative effects for parental pressure. Results suggest the need for closer lines of communication between home and school.…

Highly sensitive determination of atropine using cobalt oxide nanostructures: Influence of functional groups on the signal sensitivity

Energy Technology Data Exchange (ETDEWEB)

Soomro, Razium Ali, E-mail: raziumsoomro@gmail.com [Interface Analysis Centre, School of Physics, University of Bristol, Bristol, BS8 1TL (United Kingdom); National Centre of Excellence in Analytical Chemistry, University of Sindh, Jamshoro, 76080 (Pakistan); Nafady, Ayman [Department of Chemistry, College of Science, King Saud University, Riyadh (Saudi Arabia); Department of Chemistry, Faculty of Science, Sohag University, Sohag (Egypt); Hallam, Keith Richard [Interface Analysis Centre, School of Physics, University of Bristol, Bristol, BS8 1TL (United Kingdom); Jawaid, Sana [National Centre of Excellence in Analytical Chemistry, University of Sindh, Jamshoro, 76080 (Pakistan); Al Enizi, Abdullah [Department of Chemistry, College of Science, King Saud University, Riyadh (Saudi Arabia); Sherazi, Syed Tufail Hussain; Sirajuddin [National Centre of Excellence in Analytical Chemistry, University of Sindh, Jamshoro, 76080 (Pakistan); Ibupoto, Zafar Hussain [Dr M.A. Kazi Institute of Chemistry, University of Sindh, Jamshoro, 76080 (Pakistan); Willander, Magnus [Department of Science and Technology, Campus Norrkoping, Linkoping University, SE-60174, Norrkoping (Sweden)

2016-12-15

This study describes sensitive determination of atropine using glassy carbon electrodes (GCE) modified with Co{sub 3}O{sub 4} nanostructures. The as-synthesised nanostructures were grown using cysteine (CYS), glutathione (GSH) and histidine (HYS) as effective templates under hydrothermal action. The obtained morphologies revealed interesting structural features, including both cavity-based and flower-shaped structures. The as-synthesised morphologies were noted to actively participate in electro-catalysis of atropine (AT) drug where GSH-assisted structures exhibited the best signal response in terms of current density and over-potential value. The study also discusses the influence of functional groups on the signal sensitivity of atropine electro-oxidation. The functionalisation was carried with the amino acids originally used as effective templates for the growth of Co{sub 3}O{sub 4} nanostructures. The highest increment was obtained when GSH was used as the surface functionalising agent. The GSH-functionalised Co{sub 3}O{sub 4}-modified electrode was utilised for the electro-chemical sensing of AT in a concentration range of 0.01–0.46 μM. The developed sensor exhibited excellent working linearity (R{sup 2} = 0.999) and signal sensitivity up to 0.001 μM of AT. The noted high sensitivity of the sensor is associated with the synergy of superb surface architectures and favourable interaction facilitating the electron transfer kinetics for the electro-catalytic oxidation of AT. Significantly, the developed sensor demonstrated excellent working capability when used for AT detection in human urine samples with strong anti-interference potential against common co-existing species, such as glucose, fructose, cysteine, uric acid, dopamine and ascorbic acid. - Highlights: • Template-assisted growth of Co{sub 3}O{sub 4} nanostructures. • Shape-dependent electro-catalysis of atropine. • Effect of functionalisation of signal sensitivity.

Vertically aligned single-walled carbon nanotubes as low-cost and high electrocatalytic counter electrode for dye-sensitized solar cells.

Science.gov (United States)

Dong, Pei; Pint, Cary L; Hainey, Mel; Mirri, Francesca; Zhan, Yongjie; Zhang, Jing; Pasquali, Matteo; Hauge, Robert H; Verduzco, Rafael; Jiang, Mian; Lin, Hong; Lou, Jun

2011-08-01

A novel dye-sensitized solar cell (DSSC) structure using vertically aligned single-walled carbon nanotubes (VASWCNTs) as the counter electrode has been developed. In this design, the VASWCNTs serve as a stable high surface area and highly active electrocatalytic counter-electrode that could be a promising alternative to the conventional Pt analogue. Utilizing a scalable dry transfer approach to form a VASWCNTs conductive electrode, the DSSCs with various lengths of VASWCNTs were studied. VASWCNTs-DSSC with 34 μm original length was found to be the optimal choice in the present study. The highest conversion efficiencies of VASWCNTs-DSSC achieved 5.5%, which rivals that of the reference Pt DSSC. From the electrochemical impedance spectroscopy analysis, it shows that the new DSSC offers lower interface resistance between the electrolyte and the counter electrode. This reproducible work emphasizes the promise of VASWCNTs as efficient and stable counter electrode materials in DSSC device design, especially taking into account the low-cost merit of this promising material.

Achievement Motivation of the High School Students: A Case Study among Different Communities of Goalpara District of Assam

Science.gov (United States)

Sarangi, C.

2015-01-01

Achievement motivation is a consistent striving force of an individual to achieve success to a certain standard of excellence in competing situation. In this study an attempt was made to study the effect of achievement motivation on the academic achievement of the high school students of tribal and non tribal communities in relation to their sex…

Possibilities and limits of digital industrial radiology: the new high contrast sensitivity technique - Examples and system theoretical analysis

International Nuclear Information System (INIS)

Zscherpel, U.; Ewert, U.; Bavendiek, K.

2007-01-01

During the last years more and more reports about film replacement techniques are published using different ways to prove the required and obtained image quality. The motivation is usually cost reduction due to shorter exposure times and lower storage costs, smaller space requirements and elimination of chemical processing inclusive associated waste handling and disposal. There are no other publications known, which explore the upper limits of image quality achievable by the new digital techniques. This is important for inspection of safety relevant and high risk parts, as e.g. in nuclear or aerospace industries. A new calibration and measurement procedure for digital detector arrays (DDA) was explored to obtain the maximum signal/noise ratio achievable with DDAs. This procedure yields a contrast sensitivity which allows distinguishing wall thickness changes of up to 1/1000 of the penetrated material thickness. Standard film radiography using NDT film systems (with and without lead screens) achieves a wall thickness contrast which is not better than 1/100 even with the best film system class (class 'C1' according to EN 584-1 or 'special' according to ASTM E 1815). Computed Radiography (CR) using phosphor imaging plates is a true film replacement technique without enhancement of the image quality compared to NDT film systems. The comparison is based on parameter studies which measure signal/noise ratios and determine the basic spatial resolution as well as a comparison of radiological images with fine flaws. (authors)

The nature and nurture of high IQ: an extended sensitive period for intellectual development.

Science.gov (United States)

Brant, Angela M; Munakata, Yuko; Boomsma, Dorret I; Defries, John C; Haworth, Claire M A; Keller, Matthew C; Martin, Nicholas G; McGue, Matthew; Petrill, Stephen A; Plomin, Robert; Wadsworth, Sally J; Wright, Margaret J; Hewitt, John K

2013-08-01

IQ predicts many measures of life success, as well as trajectories of brain development. Prolonged cortical thickening observed in individuals with high IQ might reflect an extended period of synaptogenesis and high environmental sensitivity or plasticity. We tested this hypothesis by examining the timing of changes in the magnitude of genetic and environmental influences on IQ as a function of IQ score. We found that individuals with high IQ show high environmental influence on IQ into adolescence (resembling younger children), whereas individuals with low IQ show high heritability of IQ in adolescence (resembling adults), a pattern consistent with an extended sensitive period for intellectual development in more-intelligent individuals. The pattern held across a cross-sectional sample of almost 11,000 twin pairs and a longitudinal sample of twins, biological siblings, and adoptive siblings.

Robust and Fragile Mathematical Identities: A Framework for Exploring Racialized Experiences and High Achievement among Black College Students

Science.gov (United States)

McGee, Ebony O.

2015-01-01

I introduce the construct of fragile and robust identities for the purpose of exploring the experiences that influenced the mathematical and racial identities of high-achieving Black college students in mathematics and engineering. These students maintained high levels of academic achievement in these fields while enduring marginalization,…

High-sensitivity β-Ga_2O_3 solar-blind photodetector on high-temperature pretreated c-plane sapphire substrate

KAUST Repository

Qian, Ling-Xuan; Zhang, Hua-Fan; Lai, P. T.; Wu, Ze-Han; Liu, Xing-Zhao

2017-01-01

-annealing temperature must be sufficiently high to offset the rise of the dark current and thus achieve a remarkable improvement in the photodetection properties. As a result, the PD fabricated on the 1050 degrees C-annealed substrate exhibited extremely high

Fabrication of an SPR Sensor Surface with Antifouling Properties for Highly Sensitive Detection of 2,4,6-Trinitrotoluene Using Surface-Initiated Atom Transfer Polymerization

Directory of Open Access Journals (Sweden)

Kiyoshi Toko

2013-07-01

Full Text Available In this study, we modified a surface plasmon resonance immunosensor chip with a polymer using surface-initiated atom transfer polymerization (SI-ATRP for the highly sensitive detection of 2,4,6-trinitrotoluene (TNT. To immobilize a TNT analogue on the polymer, mono-2-(methacryloyloxyethylsuccinate (MES, which has a carboxyl group, was used in this study. However, the anti-TNT antibody may adsorb non-specifically on the polymer surface by an electrostatic interaction because MES is negatively charged. Therefore, a mixed monomer with MES and diethylaminoethylmethacrylate (DEAEM, which has a tertiary amino group and is positively charged, was prepared to obtain electroneutrality for suppressing the nonspecific adsorption. The detection of TNT was performed by inhibition assay using the polymer surface. To ensure high sensitivity to TNT, the affinity between the surface and the antibody was optimized by controlling the density of the initiator for ATRP by mixing two types of self-assembled monolayer reagents. As a result, a limit of detection of 5.7 pg/mL (ppt for TNT was achieved using the optimized surface.

Highly sensitive uric acid biosensor based on individual zinc oxide micro/nanowires

International Nuclear Information System (INIS)

Zhao, Yanguang; Yan, Xiaoqin; Kang, Zhuo; Lin, Pei; Fang, Xiaofei; Lei, Yang; Ma, Siwei; Zhang, Yue

2013-01-01

We describe the use of individual zinc oxide (ZnO) micro/nanowires in an electrochemical biosensor for uric acid. The wires were synthesized by chemical vapor deposition and possess uniform morphology and high crystallinity as revealed by scanning electron microscopy, X-ray diffraction, and photoluminescence studies. The enzyme uricase was then immobilized on the surface of the ZnO micro/nanowires by physical adsorption, and this was proven by Raman spectroscopy and fluorescence microscopy. The resulting uric acid biosensor undergoes fast electron transfer between the active site of the enzyme and the surface of the electrode. It displays high sensitivity (89.74 μA cm −2 mM −1 ) and a wide linear analytical range (between 0.1 mM and 0.59 mM concentrations of uric acid). This study also demonstrates the potential of the use of individual ZnO micro/nanowires for the construction of highly sensitive nano-sized biosensors. (author)

Development of miniature γ dose rate monitor with high sensitivity

International Nuclear Information System (INIS)

Shi Huilu; Tuo Xianguo; Xi Dashun; Tang Rong; Mu Keliang; Yang Jianbo

2009-01-01

This paper introduces a miniature γ dose rate monitor with high sensitivity which design based on single chip microcomputer, it can continue monitoring γ dose rate and then choose wire or wireless communications to sent the monitoring data to host according to the actual conditions. It has two kinds of power supply system, AC power supply system and battery which can be chose by concrete circumstances. The design idea and implementation technology of hardware and software and the system structure of the monitor are detailed illustrated in this paper. The experimental results show that measurable range is 0.1 mR/h-200 mR/h, the sensitivity of γ is 90 cps/mR/h, dead time below 200 us, error of stability below ±10%. (authors)

RAMA casein zymography: Time-saving and highly sensitive casein zymography for MMP7 and trypsin.

Science.gov (United States)

Yasumitsu, Hidetaro; Ozeki, Yasuhiro; Kanaly, Robert A

2016-11-01

To detect metalloproteinase-7 (MMP7), zymography is conducted using a casein substrate and conventional CBB stain. It has disadvantages because it is time consuming and has low sensitivity. Previously, a sensitive method to detect MMP7 up to 30 pg was reported, however it required special substrates and complicated handlings. RAMA casein zymography described herein is rapid, sensitive, and reproducible. By applying high-sensitivity staining with low substrate conditions, the staining process is completed within 1 h and sensitivity was increased 100-fold. The method can detect 10 pg MMP7 by using commercially available casein without complicated handlings. Moreover, it increases detection sensitivity for trypsin. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Palladium Gate All Around - Hetero Dielectric -Tunnel FET based highly sensitive Hydrogen Gas Sensor

Science.gov (United States)

Madan, Jaya; Chaujar, Rishu

2016-12-01

The paper presents a novel highly sensitive Hetero-Dielectric-Gate All Around Tunneling FET (HD-GAA-TFET) based Hydrogen Gas Sensor, incorporating the advantages of band to band tunneling (BTBT) mechanism. Here, the Palladium supported silicon dioxide is used as a sensing media and sensing relies on the interaction of hydrogen with Palladium-SiO2-Si. The high surface to volume ratio in the case of cylindrical GAA structure enhances the fortuities for surface reactions between H2 gas and Pd, and thus improves the sensitivity and stability of the sensor. Behaviour of the sensor in presence of hydrogen and at elevated temperatures is discussed. The conduction path of the sensor which is dependent on sensors radius has also been varied for the optimized sensitivity and static performance analysis of the sensor where the proposed design exhibits a superior performance in terms of threshold voltage, subthreshold swing, and band to band tunneling rate. Stability of the sensor with respect to temperature affectability has also been studied, and it is found that the device is reasonably stable and highly sensitive over the bearable temperature range. The successful utilization of HD-GAA-TFET in gas sensors may open a new door for the development of novel nanostructure gas sensing devices.

Determination of Chlorinated Hydrocarbons in Water Using Highly Sensitive Mid-Infrared Sensor Technology

Science.gov (United States)

Lu, Rui; Mizaikoff, Boris; Li, Wen-Wei; Qian, Chen; Katzir, Abraham; Raichlin, Yosef; Sheng, Guo-Ping; Yu, Han-Qing

2013-08-01

Chlorinated aliphatic hydrocarbons and chlorinated aromatic hydrocarbons (CHCs) are toxic and carcinogenic contaminants commonly found in environmental samples, and efficient online detection of these contaminants is still challenging at the present stage. Here, we report an advanced Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR) sensor for in-situ and simultaneous detection of multiple CHCs, including monochlorobenzene, 1,2-dichlorobenzene, 1,3-dichlorobenzene, trichloroethylene, perchloroethylene, and chloroform. The polycrystalline silver halide sensor fiber had a unique integrated planar-cylindric geometry, and was coated with an ethylene/propylene copolymer membrane to act as a solid phase extractor, which greatly amplified the analytical signal and contributed to a higher detection sensitivity compared to the previously reported sensors. This system exhibited a high detection sensitivity towards the CHCs mixture at a wide concentration range of 5~700 ppb. The FTIR-ATR sensor described in this study has a high potential to be utilized as a trace-sensitive on-line device for water contamination monitoring.

Feedback-enhanced sensitivity in optomechanics

DEFF Research Database (Denmark)

Harris, Glen I.; Andersen, Ulrik L.; Knittel, Joachim

2012-01-01

The intracavity power, and hence sensitivity, of optomechanical sensors is commonly limited by parametric instability. Here we characterize the degradation of sensitivity induced by parametric instability in a micron-scale cavity optomechanical system. Feedback via optomechanical transduction...... and electrical gradient force actuation is applied to suppress the parametric instability. As a result a 5.4-fold increase in mechanical motion transduction sensitivity is achieved to a final value of 1.9×10-18 mHz-1/2....

The CO_2 absorption spectrum in the 2.3 µm transparency window by high sensitivity CRDS: (I) Rovibrational lines

International Nuclear Information System (INIS)

Vasilchenko, S.; Konefal, M.; Mondelain, D.; Kassi, S.; Čermák, P.; Tashkun, S.A.; Perevalov, V.I.; Campargue, A.

2016-01-01

The absorption of carbon dioxide is very weak near 2.3 µm which makes this transparency window of particular interest for the study of Venus’ lower atmosphere. As a consequence of the weakness of the transitions located in this region, previous experimental data are very scarce and spectroscopic databases provide calculated line lists which should be tested and validated by experiment. In this work, we use the Cavity Ring Down Spectroscopy (CRDS) technique for a high sensitivity characterization of the CO_2 absorption spectrum in two spectral intervals of the 2.3 µm window: 4248–4257 and 4295–4380 cm"−"1 which were accessed using a Distributed Feed Back (DFB) diode laser and a Vertical External Cavity Surface Emitting Laser (VECSEL) as light sources, respectively. The achieved sensitivity (noise equivalent absorption, α_m_i_n, on the order of 5×10"−"1"0 cm"−"1) allowed detecting numerous new transitions with intensity values down to 5×10"−"3"0 cm/molecule. The rovibrational assignments were performed by comparison with available theoretical line lists in particular those obtained at IAO Tomsk using the global effective operator approach. Hot bands of the main isotopologue and "1"6O"1"2C"1"8O bands were found to be missing in the HITRAN database while they contribute importantly to the absorption in the region. Additional CRDS spectra of a CO_2 sample highly enriched in "1"8O were recorded in order to improve the spectroscopy of this isotopologue. As a result about 700 lines of "1"6O"1"2C"1"8O, "1"6O"1"2C"1"7O, "1"7O"1"2C"1"8O, "1"2C"1"8O_2 and "1"3C"1"8O_2 were newly measured. The status of the different databases (HITRAN, CDSD, variational calculations) in the important 2.3 µm transparency window is discussed. Possible improvements to correct evidenced deficiencies are suggested. - Highlights: • High sensitivity CRDS with a VECSEL in the 2.3 µm transparency window of CO_2. • Natural and "1"8O enriched CO_2 spectra recorded with

Heap: a highly sensitive and accurate SNP detection tool for low-coverage high-throughput sequencing data

KAUST Repository

Kobayashi, Masaaki

2017-04-20

Recent availability of large-scale genomic resources enables us to conduct so called genome-wide association studies (GWAS) and genomic prediction (GP) studies, particularly with next-generation sequencing (NGS) data. The effectiveness of GWAS and GP depends on not only their mathematical models, but the quality and quantity of variants employed in the analysis. In NGS single nucleotide polymorphism (SNP) calling, conventional tools ideally require more reads for higher SNP sensitivity and accuracy. In this study, we aimed to develop a tool, Heap, that enables robustly sensitive and accurate calling of SNPs, particularly with a low coverage NGS data, which must be aligned to the reference genome sequences in advance. To reduce false positive SNPs, Heap determines genotypes and calls SNPs at each site except for sites at the both ends of reads or containing a minor allele supported by only one read. Performance comparison with existing tools showed that Heap achieved the highest F-scores with low coverage (7X) restriction-site associated DNA sequencing reads of sorghum and rice individuals. This will facilitate cost-effective GWAS and GP studies in this NGS era. Code and documentation of Heap are freely available from https://github.com/meiji-bioinf/heap (29 March 2017, date last accessed) and our web site (http://bioinf.mind.meiji.ac.jp/lab/en/tools.html (29 March 2017, date last accessed)).