Aircraft Hydraulic Systems Dynamic Analysis. Volume II. Transient Analysis (HYTRAN) Computer Program Technical Description

DTIC Science & Technology

1977-02-01

Corporation, under contract F3615-74-C- 2016 . A The effort was sponsored by the Air Force Aero Propulsion Laboratory, Air Force Systems Command, Wright...2100 DT(IVOLO) = D(MIVOLO) D’T(PG) IY DT(PRESIPS) 2100 I)T(KBULK) = BULK( KTEMPI (IND) )*I)T(NDELT)/D(MAVOLO) DT(NVZ) = DT(NZ)+. 0I/DOT (KBULK) 6.71-4

49 CFR 27.71 - Airport facilities.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 1 2011-10-01 2011-10-01 false Airport facilities. 27.71 Section 27.71... Administration Programs: Airports, Railroads, and Highways § 27.71 Airport facilities. (a) This section applies to all terminal facilities and services owned, leased, or operated on any basis by a recipient of DOT...

75 FR 26320 - Fourteenth Plenary Meeting, RTCA Special Committee 205/EUROCAE WG 71: Software Considerations in...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-11

... Special Committee 205/EUROCAE WG 71: Software Considerations in Aeronautical Systems AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of RTCA Special Committee 205/EUROCAE WG 71: Software... meeting of RTCA Special Committee 205/EUROCAE WG 71: Software Considerations in Aeronautical Systems...

75 FR 2924 - Thirteenth Plenary Meeting, RTCA Special Committee 205/EUROCAE WG 71: Software Considerations in...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-19

... Special Committee 205/EUROCAE WG 71: Software Considerations in Aeronautical Systems AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of RTCA Special Committee 205/EUROCAE WG 71: Software... meeting of RTCA Special Committee 205/EUROCAE WG 71: Software Considerations in Aeronautical Systems...

76 FR 50812 - Seventeenth Meeting: RTCA Special Committee 205/EUROCAE WG-71: Software Considerations in...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-16

... Committee 205/EUROCAE WG-71: Software Considerations in Aeronautical Systems AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of RTCA Special Committee 205/EUROCAE WG-71 meeting: Software... of RTCA Special Committee 205/EUROCAE WG-71: Software Considerations in Aeronautical Systems Agenda...

76 FR 16469 - Sixteenth Meeting: RTCA Special Committee 205/EUROCAE WG-71: Software Considerations in...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-23

... Committee 205/EUROCAE WG-71: Software Considerations in Aeronautical Systems AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of RTCA Special Committee 205/EUROCAE WG-71 meeting: Software... of RTCA Special Committee 205/EUROCAE WG-71: Software Considerations in Aeronautical Systems Agenda...

Push-out bond strengths of fiber-reinforced composite posts with various resin cements according to the root level

PubMed Central

Chang, Hoon-Sang; Noh, Young-Sin; Lee, Yoon; Min, Kyung-San

2013-01-01

PURPOSE The aim of this study was to determine whether the push-out bond strengths between the radicular dentin and fiber reinforced-composite (FRC) posts with various resin cements decreased or not, according to the coronal, middle or apical level of the root. MATERIALS AND METHODS FRC posts were cemented with one of five resin cement groups (RelyX Unicem: Uni, Contax with activator & LuxaCore-Dual: LuA, Contax & LuxaCore-Dual: Lu, Panavia F 2.0: PA, Super-Bond C&B: SB) into extracted human mandibular premolars. The roots were sliced into discs at the coronal, middle and apical levels. Push-out bond strength tests were performed with a universal testing machine at a crosshead speed of 0.5 mm/min, and the failure aspect was analyzed. RESULTS There were no significant differences (P>.05) in the bond strengths of the different resin cements at the coronal level, but there were significant differences in the bond strengths at the middle and apical levels (P<.05). Only the Uni and LuA cements did not show any significant decrease in their bond strengths at all the root levels (P>.05); all other groups had a significant decrease in bond strength at the middle or apical level (P<.05). The failure aspect was dominantly cohesive at the coronal level of all resin cements (P<.05), whereas it was dominantly adhesive at the apical level. CONCLUSION All resin cement groups showed decreases in bond strengths at the middle or apical level except LuA and Uni. PMID:24049569

Quick test for percent of deleterious material.

DOT National Transportation Integrated Search

2009-08-28

The Missouri Department of Transportation (MoDOT) is considering the replacement of its deleterious : materials test method (TM-71) with test methods that are more objective. MoDOT contracted with the Missouri : University of Science and Technology (...

Characteristics of Navy Medium-Weight High-Impact Shock Machine

DTIC Science & Technology

1951-09-14

Ar 2-4~ -C 0 ofoL "- oili 0jit -1 b. V’ A . -- c- MC a y - w CmLUA ~ E~8.9. - flb. A 9 Er IL v II - W43 4P " It IIf ~NRL REPORT I CHARACTERISTICS OF...this machine under specification operation. A comnarison of datta is intended to correlate this shock to shipboard shock experienced in actual combat...table reversal are discussed, and it is shown that this secondsry shock can be the largest under certain condition. Theoretical equations of motion are

The effect of polymer dots on bioactivity of mouse sperm in vitro

NASA Astrophysics Data System (ADS)

Feng, Gang; Chen, Qiang; Zhai, Peng; Wang, Xiaomei; Lin, Guimiao; Xu, Gaixia; Chen, Danni

2014-09-01

Objective: In recent years, semiconducting polymer dots (Pdots)have caught considerable attention for their outstanding optical characteristics in biomedical imaging applications. Not as semiconductor quantum dots, Pdots are composed of nonmetallic material and their biological effects remain unclear. In this work, we investigated the effects of a band new polymer dots on bioactivity of mouse sperm using a computer-aided sperm analysis system(CASA) and an in vitro fertilization (IVF) model. Methods: The semiconducting polymer dots used in this study is CN-PPV Pdots, which emits in the orange wavelength range with high brightness. Epididymal mouse sperm were collected from 7-8weeks old Balb/c mouse. Firstly, CN-PPV Pdots was added into the Human Tubal Fluid (HTF) media at various concentrations (0, 1, 10, 100 nmol/L respectively ), then sperm bioactivity and vitality were evaluated every 10 minutes. Secondly, the treated sperm were co-cultured with matured oocytes in HTF media, fertilization rate and oocytes development were recorded after 24 hours co-incubation. Results: Sperm viability in the control group (0 nmol/L) and experimental group (1, 10,100 nmol/L) were 57.20+/-4.51%, 58.17+/-4.81%, 55.50+/-4.52%, 46.26%+/-3.83%, respectively. Fertilization rate in different groups showed no obvious differences, control group (0 nmol/L) and experimental group (1, 10, 100 nmol/L) were 38.75+/-1.71%, 37.01+/-4.69%, 32.75+/-1.71%, 35.24+/-2.37%, respectively. Conclusion: Our data indicated that the CN-PPV Pdots had a very high biocompatibility on sperm in both the activation and the IVF process, even in extreme high Pdots concentration,the sperm bioactivity only got slight restrained. The effect of CN-PPV Pdots seems has no or little toxicity,and the long-term embryonic development has yet to be verified.

Principles of Work Sample Testing. 4. Generalizability

DTIC Science & Technology

1979-04-01

ARI TECHNICAL REPORT TR-79-A11 Principles of Work Sample Testing: IV. Generallzability , by ,lobert M. Guion Gail H. Ironson BOWLING GREEN STATE...UNIVERSITY Bowling Green , Ohio 43403 April 1979 or -Contract DAHC 19-77-C-0007 d CD, LUa.J Prepared for -_J ;=U.S. ARMY RESEARCH INSTITUTE for the...ORGANIZATION NAME AND ADDRESS 10. PROG RAM ELEMENT. PROJECT, TASK A REA & WORK UNIT NUMBERS Bowling Green State University __ Bowling Green , Ohio 43403

GPC: General Polygon Clipper library

NASA Astrophysics Data System (ADS)

Murta, Alan

2015-12-01

The University of Manchester GPC library is a flexible and highly robust polygon set operations library for use with C, C#, Delphi, Java, Perl, Python, Haskell, Lua, VB.Net and other applications. It supports difference, intersection, exclusive-or and union clip operations, and polygons may be comprised of multiple disjoint contours. Contour vertices may be given in any order - clockwise or anticlockwise, and contours may be convex, concave or self-intersecting, and may be nested (i.e. polygons may have holes). Output may take the form of either polygon contours or tristrips, and hole and external contours are differentiated in the result.

Facile synthesis of luminescent carbon dots from mangosteen peel by pyrolysis method

NASA Astrophysics Data System (ADS)

Aji, Mahardika Prasetya; Susanto; Wiguna, Pradita Ajeng; Sulhadi

2017-06-01

Carbon dots (C-Dots) from mangosteen peel has been synthesized by pyrolysis method. Synthesis of C-Dots is done using precursor solution which is prepared from extract of mangosteen peel as carbon source and urea as passivation agent. C-Dots is successfully formed with absorbance spectra at wavelength 350-550 nm. Urea affects to the formed C-Dots, while the absorbance and the luminescent spectra are independent toward urea. C-Dots from extract of mangosteen peel has size in range 2-15 nm. The absorbance peaks of C-Dots shows significant wavelength shift at visible region as the increasing of synthesized temperature. Shift of wavelength absorbance indicates the change of electronic transition of C-Dots. Meanwhile, the luminescent of C-Dots can be controlled by synthesized temperature as well. C-Dots luminescent were increasing as higher synthesized temperature. It was shown by the shift of wavelength emission into shorter wavelength, 465 nm at 200 °C, 450 nm at 250 °C, and 423 nm at 300 °C. Synthesized temperature also affects size of C-Dots. It has size 10-15 nm at 200 °C, 7-11 nm at 250 °C and 2-4 nm at 300 °C. In addition, temperature corresponds to the structure of carbon chains and C-N configuration of formed C-Dots from mangosteen peel extract.

Growth rate and surfactant-assisted enhancements of rare-earth arsenide InGaAs nanocomposites for terahertz generation

NASA Astrophysics Data System (ADS)

Salas, R.; Guchhait, S.; Sifferman, S. D.; McNicholas, K. M.; Dasika, V. D.; Jung, D.; Krivoy, E. M.; Lee, M. L.; Bank, S. R.

2017-09-01

We report the effects of the growth rate on the properties of iii-v nanocomposites containing rare-earth-monopnictide nanoparticles. In particular, the beneficial effects of surfactant-assisted growth of LuAs:In0.53Ga0.47As nanocomposites were found to be most profound at reduced LuAs growth rates. Substantial enhancement in the electrical and optical properties that are beneficial for ultrafast photoconductors was observed and is attributed to the higher structural quality of the InGaAs matrix in this new growth regime. The combined enhancements enabled a >50% increase in the amount of LuAs that could be grown without degrading the quality of the InGaAs overgrowth. Dark resistivity increased by ˜25× while maintaining carrier mobilities over 3000 cm2/V s; carrier lifetimes were reduced by >2×, even at high depositions of LuAs. The combined growth rate and surfactant enhancements offer a previously unexplored regime to enable high-performance fast photoconductors that may be integrated with telecom components for compact, broadly tunable, heterodyne THz source and detectors.

Refractive-Index Tuning of Highly Fluorescent Carbon Dots.

PubMed

Kumar, Vijay Bhooshan; Sahu, Amit Kumar; Mohsin, Abu S M; Li, Xiangping; Gedanken, Aharon

2017-08-30

In this manuscript, we report the refractive-index (RI) modulation of various concentrations of nitrogen-doped carbon dots (N@C-dots) embedded in poly(vinyl alcohol) (PVA) polymer. The dispersion and size distribution of N@C-dots embedded within PVA have been investigated using electron microscopy. The RI of PVA-N@C-dots can be enhanced by increasing the doping concentration of highly fluorescent C-dots (quantum yield 44%). This is demonstrated using ultraviolet-visible (UV-visible), photoluminscence, Raman, and Fourier transform infrared (FTIR) spectroscopy measurements. The Mie scattering of light on N@C-dots was applied for developing the relationship between RI tuning and absorption cross section of N@C-dots. The extinction cross section of N@C-dot thin films can be rapidly enhanced by either tuning the RI or increasing the concentration of N@C-dots. The developed method can be used as effective RI contrast for various applications such as holography creation and bioimaging.

Presence of photoluminescent carbon dots in Nescafe® original instant coffee: applications to bioimaging.

PubMed

Jiang, Chengkun; Wu, Hao; Song, Xiaojie; Ma, Xiaojun; Wang, Jihui; Tan, Mingqian

2014-09-01

The presence of the carbon dots (C-dots) in food is a hotly debated topic and our knowledge about the presence and the use of carbon dots (C-dots) in food is still in its infancy. We report the finding of the presence of photoluminescent (PL) C-dots in commercial Nescafe instant coffee. TEM analysis reveals that the extracted C-dots have an average size of 4.4 nm. They were well-dispersed in water and strongly photoluminescent under the excitation of ultra-violet light with a quantum yield (QY) about 5.5%, which were also found to possess clear upconversion PL properties. X-ray photoelectron spectroscopy characterization demonstrates that the C-dots contain C, O and N three elements with the relative contents ca. 30.1, 62.2 and 7.8%. The X-ray diffraction (XRD) analysis indicates that the C-dots are amorphous. Fourier-transform infrared (FTIR) spectra were employed to characterize the surface groups of the C-dots. The C-dots show a pH independent behavior by varying the pH value from 2 to 11. The cytotoxicity study revealed that the C-dots did not cause any toxicity to cells at a concentration as high as 20 mg/mL. The C-dots have been directly applied in cells and fish imaging, which suggested that the C-dots present in commercial coffee may have more potential biological applications. Copyright © 2014. Published by Elsevier B.V.

Biocompatible yogurt carbon dots: evaluation of utilization for medical applications

NASA Astrophysics Data System (ADS)

Dinç, Saliha; Kara, Meryem; Demirel Kars, Meltem; Aykül, Fatmanur; Çiçekci, Hacer; Akkuş, Mehmet

2017-09-01

In this study, carbon dots (CDs) were produced from yogurt, a fermented milk product, via microwave-assisted process (800 W) in 30 min without using any additional chemical agents. Yogurt CDs had outstanding nitrogen and oxygen ratios. These dots were monodisperse and about 2 nm sized. The toxicological assessments of yogurt carbon dots in human cancer cells and normal epithelial cells and their fluorescence imaging in living cell system were carried out. Yogurt carbon dots had intense fluorescent signal under confocal microscopy and good fluorescence stability in living cell system. The resulting yogurt carbon dots exhibited high biocompatibility up to 7.1 mg/mL CD concentration which may find utilization in medical applications such as cellular tracking, imaging and drug delivery. Yogurt carbon dots have potential to be good diagnostic agents to visualize cancer cells which may be developed as a therapeutic carrier.

Spectroscopic characteristics of carbon dots (C-dots) derived from carbon fibers and conversion to sulfur-bridged C-dots nanosheets.

PubMed

Vinci, John C; Ferrer, Ivonne M; Guterry, Nathan W; Colón, Verónica M; Destino, Joel F; Bright, Frank V; Colón, Luis A

2015-09-01

We synthesized sub-10 nm carbon nanoparticles (CNPs) consistent with photoluminescent carbon dots (C-dots) from carbon fiber starting material. The production of different C-dots fractions was monitored over seven days. During the course of the reaction, one fraction of C-dots species with relatively high photoluminescence was short-lived, emerging during the first hour of reaction but disappearing after one day of reaction. Isolation of this species during the first hour of the reaction was crucial to obtaining higher-luminescent C-dots species. When the reaction proceeded for one week, the appearance of larger nanostructures was observed over time, with lateral dimensions approaching 200 nm. The experimental evidence suggests that these larger species are formed from small C-dot nanoparticles bridged together by sulfur-based moieties between the C-dot edge groups, as if the C-dots polymerized by cross-linking the edge groups through sulfur bridges. Their size can be tailored by controlling the reaction time. Our results highlight the variety of CNP products, from sub-10 nm C-dots to ~200 nm sulfur-containing carbon nanostructures, that can be produced over time during the oxidation reaction of the graphenic starting material. Our work provides a clear understanding of when to stop the oxidation reaction during the top-down production of C-dots to obtain highly photoluminescent species or a target average particle size.

Enhanced photoluminescence and characterization of multicolor carbon dots using plant soot as a carbon source.

PubMed

Tan, Mingqian; Zhang, Lingxin; Tang, Rong; Song, Xiaojie; Li, Yimin; Wu, Hao; Wang, Yanfang; Lv, Guojun; Liu, Wanfa; Ma, Xiaojun

2013-10-15

Carbon dots (C-dots) are a class of novel fluorescent nanomaterials, which have drawn great attention for their potential applications in bio-nanotechnology. Multicolor C-dots have been synthesized by chemical nitric acid oxidation using the reproducible plant soot as raw material. TEM analysis reveals that the prepared C-dots have an average size of 3.1 nm. The C-dots are well dispersed in aqueous solution and are strongly fluorescent under the irradiation of ultra-violet light. X-ray photoelectron spectroscopy characterization demonstrates that the O/C atomic ratio for C-dots change to from 0.207 to 0.436 due to the chemical oxidation process. The photo bleaching experiment reveals that the C-dots show excellent photostability as compared with the conventional organic dyes, fluorescein and rhodamine B. The fluorescence intensity of the C-dots did not change significantly in the pH range of 3-10. To further enhance the fluorescence quantum yield, the C-dots were surface modified with four types of passivation ligands, 4,7,10-trioxa-1,13-tridecanediamine (TTDDA), poly-L-lysine (PLL), cysteine and chitosan and the fluorescence quantum yields of the TTDDA, PLL, cysteine and chitosan passivated C-dots were improved 1.53-, 5.94-, 2.00- and 3.68-fold, respectively. Fourier-transform infrared (FTIR) spectra were employed to characterize the surface groups of the C-dots. The bio-application of the C-dots as fluorescent bio-probes was evaluated in cell imaging and ex vivo fish imaging, which suggests that the C-dots may have potential applications in biolabeling and bioimaging. Copyright © 2013 Elsevier B.V. All rights reserved.

Ga@C-dots as an antibacterial agent for the eradication of Pseudomonas aeruginosa

PubMed Central

Kumar, Vijay Bhooshan; Natan, Michal; Jacobi, Gila; Porat, Ze’ev; Banin, Ehud; Gedanken, Aharon

2017-01-01

The opportunistic pathogen Pseudomonas aeruginosa causes infections that are difficult to treat by antibiotic therapy. This research article reports on the synthesis of gallium (Ga) doped in carbon (C)-dots (Ga@C-dots) and their antimicrobial activity against free-living P. aeruginosa bacteria. The synthesis of Ga@C-dots was carried out by sonicating molten Ga (for 2.5 h) in polyethylene glycol-400, which acts as both a medium and carbon source. The resultant Ga@C-dots, having an average diameter of 9±2 nm, showed remarkably enhanced antibacterial activity compared with undoped C-dots. This was reflected by the much lower concentration of Ga doped within Ga@C-dots which was required for full inhibition of the bacterial growth. These results highlight the possibility of using Ga@C-dots as potential antimicrobial agents. PMID:28176980

Functional surface engineering of C-dots for fluorescent biosensing and in vivo bioimaging.

PubMed

Ding, Changqin; Zhu, Anwei; Tian, Yang

2014-01-21

Nanoparticles are promising scaffolds for applications such as imaging, chemical sensors and biosensors, diagnostics, drug delivery, catalysis, energy, photonics, medicine, and more. Surface functionalization of nanoparticles introduces an additional dimension in controlling nanoparticle interfacial properties and provides an effective bridge to connect nanoparticles to biological systems. With fascinating photoluminescence properties, carbon dots (C-dots), carbon-containing nanoparticles that are attracting considerable attention as a new type of quantum dot, are becoming both an important class of imaging probes and a versatile platform for engineering multifunctional nanosensors. In order to transfer C-dots from proof-of-concept studies toward real world applications such as in vivo bioimaging and biosensing, careful design and engineering of C-dot probes is becoming increasingly important. A comprehensive knowledge of how C-dot surfaces with various properties behave is essential for engineering C-dots with useful imaging properties such as high quantum yield, stability, and low toxicity, and with desirable biosensing properties such as high selectivity, sensitivity, and accuracy. Several reviews in recent years have reported preparation methods and properties of C-dots and described their application in biosensors, catalysis, photovoltatic cells, and more. However, no one has yet systematically summarized the surface engineering of C-dots, nor the use of C-dots as fluorescent nanosensors or probes for in vivo imaging in cells, tissues, and living organisms. In this Account, we discuss the major design principles and criteria for engineering the surface functionality of C-dots for biological applications. These criteria include brightness, long-term stability, and good biocompatibility. We review recent developments in designing C-dot surfaces with various functionalities for use as nanosensors or as fluorescent probes with fascinating analytical performance, and we emphasize applications in bioimaging and biosensing in live cells, tissues, and animals. In addition, we highlight our work on the design and synthesis of a C-dot ratiometric biosensor for intracellular Cu(2+) detection, and a twophoton fluorescent probe for pH measurement in live cells and tissues. We conclude this Account by outlining future directions in engineering the functional surface of C-dots for a variety of in vivo imaging applications, including dots with combined targeting, imaging and therapeutic-delivery capabilities, or high-resolution multiplexed vascular imaging. With each application C-dots should open new horizons of multiplexed quantitative detection, high-resolution fluorescence imaging, and long-term, real-time monitoring of their target.

Photoluminescent carbon dots synthesized by microwave treatment for selective image of cancer cells.

PubMed

Yang, Xudong; Yang, Xue; Li, Zhenyu; Li, Shouying; Han, Yexuan; Chen, Yang; Bu, Xinyuan; Su, Chunyan; Xu, Hong; Jiang, Yingnan; Lin, Quan

2015-10-15

In this work, a simple, low-cost and one-step microwave approach has been demonstrated for the synthesis of water-soluble carbon dots (C-dots). The average size of the resulting C-dots is about 4 nm. From the photoluminescence (PL) measurements, the C-dots exhibit excellent biocompatibility and intense PL with the high quantum yield (QY) at Ca. 25%. Significantly, the C-dots have excellent biocompatibility and the capacity to specifically target the cells overexpressing the folate receptor (FR). These exciting results indicate the as-prepared C-dots are promising biocompatible probe for cancer diagnosis and treatment. Copyright © 2015 Elsevier Inc. All rights reserved.

Definition of Small Gram Quantity Contents for Type B Radioactive Material Transportation Packages: Activity-Based Content Limitations

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

Sitaraman, S; Kim, S; Biswas, D

2010-10-27

Since the 1960's, the Department of Transportation Specification (DOT Spec) 6M packages have been used extensively for transportation of Type B quantities of radioactive materials between Department of Energy (DOE) facilities, laboratories, and productions sites. However, due to the advancement of packaging technology, the aging of the 6M packages, and variability in the quality of the packages, the DOT implemented a phased elimination of the 6M specification packages (and other DOT Spec packages) in favor of packages certified to meet federal performance requirements. DOT issued the final rule in the Federal Register on October 1, 2004 requiring that use ofmore » the DOT Specification 6M be discontinued as of October 1, 2008. A main driver for the change was the fact that the 6M specification packagings were not supported by a Safety Analysis Report for Packaging (SARP) that was compliant with Title 10 of the Code of Federal Regulations part 71 (10 CFR 71). Therefore, materials that would have historically been shipped in 6M packages are being identified as contents in Type B (and sometimes Type A fissile) package applications and addenda that are to be certified under the requirements of 10 CFR 71. The requirements in 10 CFR 71 include that the Safety Analysis Report for Packaging (SARP) must identify the maximum radioactivity of radioactive constituents and maximum quantities of fissile constituents (10 CFR 71.33(b)(1) and 10 CFR 71.33(b)(2)), and that the application (i.e., SARP submittal or SARP addendum) demonstrates that the external dose rate (due to the maximum radioactivity of radioactive constituents and maximum quantities of fissile constituents) on the surface of the packaging (i.e., package and contents) not exceed 200 mrem/hr (10 CFR 71.35(a), 10 CFR 71.47(a)). It has been proposed that a 'Small Gram Quantity' of radioactive material be defined, such that, when loaded in a transportation package, the dose rates at external points of an unshielded packaging not exceed the regulatory limits prescribed by 10 CFR 71 for non-exclusive shipments. The mass of each radioisotope presented in this paper is limited by the radiation dose rate on the external surface of the package, which per the regulatory limit should not exceed 200 mrem/hr. The results presented are a compendium of allowable masses of a variety of different isotopes (with varying impurity levels of beryllium in some of the actinide isotopes) that, when loaded in an unshielded packaging, do not result in an external dose rate on the surface of the package that exceeds 190 mrem/hr (190 mrem/hr was chosen to provide 5% conservatism relative to the regulatory limit). These mass limits define the term 'Small Gram Quantity' (SGQ) contents in the context of radioactive material transportation packages. The term SGQ is isotope-specific and pertains to contents in radioactive material transportation packages that do not require shielding and still satisfy the external dose rate requirements. Since these calculated mass limits are for contents without shielding, they are conservative for packaging materials that provide some limited shielding or if the contents are placed into a shielded package. The isotopes presented in this paper were chosen as the isotopes that Department of Energy (DOE) sites most likely need to ship. Other more rarely shipped isotopes, along with industrial and medical isotopes, are planned to be included in subsequent extensions of this work.« less

Artful and multifaceted applications of carbon dot in biomedicine.

PubMed

Jaleel, Jumana Abdul; Pramod, K

2018-01-10

Carbon dots (C-dots) are luminescent carbon nanomaterial having good biocompatibility and low toxicity. The characteristic fluorescence emission property of C-dots establishes their role in optical imaging. C-dots which are superior to fluorescent dyes and semiconductor quantum dots act as a safer in vivo imaging probe. Apart from their bioimaging application, other applications in biomedicine such as drug delivery, cancer therapy, and gene delivery were studied. In this review, we present multifaceted applications of C-dots along with their synthesis, surface passivation, doping, and toxicity profile. Copyright © 2017 Elsevier B.V. All rights reserved.

Green synthesis of fluorescent carbon dots from spices for in vitro imaging and tumour cell growth inhibition

PubMed Central

Gallo, Juan; Cerqueira, María de Fátima; Menéndez-Miranda, Mario; Costa-Fernández, José Manuel; Diéguez, Lorena; Espiña, Begoña

2018-01-01

Carbon dots have demonstrated great potential as luminescent nanoparticles in bioapplications. Although such nanoparticles appear to exhibit low toxicity compared to other metal luminescent nanomaterials, today we know that the toxicity of carbon dots (C-dots) strongly depends on the protocol of fabrication. In this work, aqueous fluorescent C-dots have been synthesized from cinnamon, red chilli, turmeric and black pepper, by a one-pot green hydrothermal method. The synthesized C-dots were firstly characterized by means of UV–vis, fluorescence, Fourier transform infrared and Raman spectroscopy, dynamic light scattering and transmission electron microscopy. The optical performance showed an outstanding ability for imaging purposes, with quantum yields up to 43.6%. Thus, the cytotoxicity of the above mentioned spice-derived C-dots was evaluated in vitro in human glioblastoma cells (LN-229 cancer cell line) and in human kidney cells (HK-2 non-cancerous cell line). Bioimaging and viability studies were performed with different C-dot concentrations from 0.1 to 2 mg·mL−1, exhibiting a higher uptake of C-dots in the cancer cultures compared to the non-cancerous cells. Results showed that the spice-derived C-dots inhibited cell viability dose-dependently after a 24 h incubation period, displaying a higher toxicity in LN-229, than in HK-2 cells. As a control, C-dots synthesized from citric acid did not show any significant toxicity in either cancerous or non-cancerous cells, implying that the tumour cell growth inhibition properties observed in the spice-derived C-dots can be attributed to the starting material employed for their fabrication. These results evidence that functional groups in the surface of the C-dots might be responsible for the selective cytotoxicity, as suggested by the presence of piperine in the surface of black pepper C-dots analysed by ESI-QTOF-MS. PMID:29527430

Photovoltaic Performance of Inverted Polymer Solar Cells Using Hybrid Carbon Quantum Dots and Absorption Polymer Materials

NASA Astrophysics Data System (ADS)

Lim, Hwain; Lee, Kyu Seung; Liu, Yang; Kim, Hak Yong; Son, Dong Ick

2018-05-01

We report the synthesis and characterization of the carbon quantum dots (C-dots) easily obtained from citric acid and ethanediamine, and also investigated structural, optical and electrical properties. The C-dots have extraordinary optical and electrical features such as absorption of ultraviolet range and effective interface for charge separation and transport in active layer, which make them attractive materials for applications in photovoltaic devices (PV). The C-dots play important roles in charge extraction in the PV structures, they can be synthesized by a simple method and used to insert in active layer of polymer solar cells. In this study, we demonstrate that improve charge transport properties of inverted polymer solar cells (iPSCs) with C-dots and structural, optical and electrical properties of C-dots. As a result, iPSCs with C-dots showed enhancement of more than 30% compared with that of the contrast device in power conversion efficiency.

A multifunctional ribonuclease A-conjugated carbon dot cluster nanosystem for synchronous cancer imaging and therapy

PubMed Central

2014-01-01

Carbon dots exhibit great potential in applications such as molecular imaging and in vivo molecular tracking. However, how to enhance fluorescence intensity of carbon dots has become a great challenge. Herein, we report for the first time a new strategy to synthesize fluorescent carbon dots (C-dots) with high quantum yields by using ribonuclease A (RNase A) as a biomolecular templating agent under microwave irradiation. The synthesized RNase A-conjugated carbon dots (RNase A@C-dots) exhibited quantum yields of 24.20%. The fluorescent color of the RNase A@C-dots can easily be adjusted by varying the microwave reaction time and microwave power. Moreover, the emission wavelength and intensity of RNase A@C-dots displayed a marked excitation wavelength-dependent character. As the excitation wavelength alters from 300 to 500 nm, the photoluminescence (PL) peak exhibits gradually redshifts from 450 to 550 nm, and the intensity reaches its maximum at an excitation wavelength of 380 nm. Its Stokes shift is about 80 nm. Notably, the PL intensity is gradually decreasing as the pH increases, almost linearly dependent, and it reaches the maximum at a pH = 2 condition; the emission peaks also show clearly a redshift, which may be caused by the high activity and perfective dispersion of RNase A in a lower pH solution. In high pH solution, RNase A tends to form RNase A warped carbon dot nanoclusters. Cell imaging confirmed that the RNase A@C-dots could enter into the cytoplasm through cell endocytosis. 3D confocal imaging and transmission electron microscopy observation confirmed partial RNase A@C-dots located inside the nucleus. MTT and real-time cell electronic sensing (RT-CES) analysis showed that the RNase A@C-dots could effectively inhibit the growth of MGC-803 cells. Intra-tumor injection test of RNase A@C-dots showed that RNase A@C-dots could be used for imaging in vivo gastric cancer cells. In conclusion, the as-prepared RNase A@C-dots are suitable for simultaneous therapy and in vivo fluorescence imaging of nude mice loaded with gastric cancer or other tumors. PMID:25177217

A multifunctional ribonuclease A-conjugated carbon dot cluster nanosystem for synchronous cancer imaging and therapy

NASA Astrophysics Data System (ADS)

Liu, Huiyang; Wang, Qin; Shen, Guangxia; Zhang, Chunlei; Li, Chao; Ji, Weihang; Wang, Chun; Cui, Daxiang

2014-08-01

Carbon dots exhibit great potential in applications such as molecular imaging and in vivo molecular tracking. However, how to enhance fluorescence intensity of carbon dots has become a great challenge. Herein, we report for the first time a new strategy to synthesize fluorescent carbon dots (C-dots) with high quantum yields by using ribonuclease A (RNase A) as a biomolecular templating agent under microwave irradiation. The synthesized RNase A-conjugated carbon dots (RNase A@C-dots) exhibited quantum yields of 24.20%. The fluorescent color of the RNase A@C-dots can easily be adjusted by varying the microwave reaction time and microwave power. Moreover, the emission wavelength and intensity of RNase A@C-dots displayed a marked excitation wavelength-dependent character. As the excitation wavelength alters from 300 to 500 nm, the photoluminescence (PL) peak exhibits gradually redshifts from 450 to 550 nm, and the intensity reaches its maximum at an excitation wavelength of 380 nm. Its Stokes shift is about 80 nm. Notably, the PL intensity is gradually decreasing as the pH increases, almost linearly dependent, and it reaches the maximum at a pH = 2 condition; the emission peaks also show clearly a redshift, which may be caused by the high activity and perfective dispersion of RNase A in a lower pH solution. In high pH solution, RNase A tends to form RNase A warped carbon dot nanoclusters. Cell imaging confirmed that the RNase A@C-dots could enter into the cytoplasm through cell endocytosis. 3D confocal imaging and transmission electron microscopy observation confirmed partial RNase A@C-dots located inside the nucleus. MTT and real-time cell electronic sensing (RT-CES) analysis showed that the RNase A@C-dots could effectively inhibit the growth of MGC-803 cells. Intra-tumor injection test of RNase A@C-dots showed that RNase A@C-dots could be used for imaging in vivo gastric cancer cells. In conclusion, the as-prepared RNase A@C-dots are suitable for simultaneous therapy and in vivo fluorescence imaging of nude mice loaded with gastric cancer or other tumors.

Supplementary descriptive notes of the Sinella and Coecobrya (Collembola: Entomobryidae) species from North America, Hawaii and Japan.

PubMed

Wu, Jun; Yan, Qibao; Zhang, Feng

2016-03-04

Many known collembolan species lack sufficient descriptive details so that further taxonomical comparison cannot be achieved. When sorting documents and materials from Prof. Jian-Xiu CHEN, Nanjing University, we found many old but valuable drafts on Sinella and Coecobrya species from North America, Hawaii and Japan. Supplementary descriptions, particularly chaetotaxy, were provided for the following species: S. agna Christiansen & Bellinger, 1980, S. alata Christiansen, 1960, S. baca Christiansen & Bellinger, 1980, S. barri Christiansen, 1960, S. hoffmani Wray, 1952, S. sexoculata (Schött, 1896), S. straminea (Folsom, 1899), S. yosiia Christiansen & Bellinger, 1992, C. akiyoshiana Yosii, 1956, C. borerae Christiansen & Bellinger, 1992, C. ishikawai Yosii, 1956, C. kukae Christiansen & Bellinger, 1992, C. lua Christiansen & Bellinger, 1992, C. nupa Christiansen & Bellinger, 1992, C. tibiotarsalis Yosii, 1964. Sinella cavernarum (Packard, 1888) was redescribed based on topotypes and more additional materials.

Controle orbital de satélites artificiais com propulsão e uso de gravidade lunar

NASA Astrophysics Data System (ADS)

Torres, K. S.; de Almeida Prado, A. F. B.

2003-08-01

A redução do custo de combustível de uma manobra é atualmente a grande prioridade de todos os programas espaciais existentes no mundo. As manobras assistidas pela gravidade são uma ótima forma de se contornar o problema pois proporcionam economias com vasto impacto no custo final da missão. Neste trabalho é feito um estudo particular do controle orbital de um satélite artificial da Terra usando a gravidade da Lua. O objetivo é estudar uma técnica econômica para uma mudança de plano de um satélite que está em órbita em volta da Terra. A idéia principal desta abordagem é enviar primeiramente o veículo espacial em direção à Lua usando uma manobra mono-impulsiva para que assim o campo gravitacional da Lua possa fazer a mudança de plano desejada (sem custo de combustível) e só então retornar o veículo aos valores iniciais de semi-eixo e excentricidade usando uma manobra bi-impulsiva tipo Hohmann. Para tanto, é assumido que a espaçonave inicia em uma órbita circular coplanar à órbita da lua em torno da Terra e a meta é colocá-la em uma órbita similar que difere da órbita inicial somente pela inclinação. São usadas equações analíticas baseadas na abordagem Patched Conics para se calcular a variação na velocidade, momento angular, energia e inclinação do veículo espacial que realiza esta manobra. Várias simulações são feitas para se avaliar as economias de combustível envolvidas.

A Introdução de Astronomia Básica para Estudantes de 5 e 6 Séries do Ensino Fundamental

NASA Astrophysics Data System (ADS)

Gonzaga, E. P.; Voelzke, M. R.

2008-09-01

Com intuito de despertar o interesse pelo estudo da astronomia, desenvolveu-se entre 2003 e 2006 no Centro Educacional do Serviço Social da Indústria situado no município de Mauá, São Paulo, um trabalho com duração de 12 meses para turmas de 11 e 12 anos, sendo três turmas por período (2003 / 2004, 2004 / 2005 e 2005 / 2006). O trabalho realizado, objetivando a introdução da astronomia básica com observações de constelações e das fases da Lua, permitindo estender-se a outros corpos celestes, iniciou-se com visita ao planetário Mundo Estelar, localizado no Ipiranga, São Paulo levantou-se a questão da importância do estudo da astronomia e foi lançado aos estudantes um trabalho de observação, com a proposta de localizar as constelações e compreender as fases da Lua, para o registro de tais observações, foram distribuídos mapas celestes, pastas, planilhas de anotações com lacunas para, constelações, fases da Lua e relatos, onde os estudantes acrescentaram pesquisas e relatórios. Os resultados dos 346 estudantes foram que 86,7% (300) concluíram a etapa de observação, destes 300 estudantes 43,3% (130) pesquisaram sobre as constelações e 19,0% (57) localizaram até quatro constelações. Dos 346 estudantes, 44,2% (153) registraram as fases da Lua equivocadamente e 10,4% (36) anexaram reportagens sobre astronomia. Conclui-se que os estudantes se dividiram em pesquisadores, sendo os estudantes que registraram e anexaram informações e, os observadores que preencheram as planilhas de observações, além de desenvolverem habilidades e competências relacionadas ao estudo da astronomia.

Astronomy at School: Measurements of the Earth-Moon Distance. (Spanish Title: Astronomía en la Escuela: Medición de la Distancia Tierra-Luna.) Astronomia na Escola: Medida da Distância Terra-Lua

NASA Astrophysics Data System (ADS)

Paolantonio, Santiago; Pintado, Olga I.

2006-12-01

The aim of this project is to approach High School students to Science. We propose to measure the Earth-Moon distance using the parallax. The observation and measurements techniques and all the calculations needed are described in this paper. The results obtained in a test experience realized during 2003 are presented. This test shows that this is a feasible project and also shows which things needed to be improved. Se plantea la propuesta de un proyecto educativo dirigido al Nivel Medio de enseñanza, consistente en la determinación de la distancia Tierra - Luna por paralaje. Se describen las técnicas de observación, mediciones y cálculos. Se proporcionan a continuación los resultados obtenidos en la experiencia piloto realizada en el 2003, la que permitió comprobar la factibilidad de llevar a cabo la propuesta, así como perfeccionar los diferentes aspectos involucrados en la misma. Propomos neste trabalho um projeto educativo dirigido ao Ensino Médio que consiste na determinação da distância Terra-Lua pelo efeito da paralaxe. As técnicas de observação, medidas e cálculos auxiliares são descritos, e os resultados obtidos numa experiência-teste realizada no ano de 2003 apresentados. Este último teste permitiu comprovar a viabilidade de execução da proposta e aperfeiçoar diversos aspectos da mesma.

Short communication; Formula for the calculation of ground temperature at 1 M depth in Turkey

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

Tezcan, A.K.

1992-06-01

This paper reports that the formula has been found by using the yearly averages of the temperatures at 1 m depth measured in 193 meteorological stations, distributed all over Turkey. It has thus become possible to determine the regional temperature value at 1 m depth at any point in Turkey, if the latitude, longitude and elevation are known. The values, calculated by the formula, can contribute to geothermal exploration in Turkey by providing values that can be compared with the observed ones, and, by becoming second values for the calculation of geothermal gradients where only single downhole temperatures are available.more » The formula has been evolved by expressing the temperatures as the linear function of latitude (La), longitude (Lo) and elevation (H): T = a + b [center dot] La + c [center dot] Lo + d [center dot] H. The derived four least square equations are a [center dot] n + b [center dot] [Sigma](La) + c [center dot] [Sigma](lo) + d [center dot] [Sigma]H = [Sigma]T a [center dot] [Sigma](La) + b [center dot] [Sigma](La)[sup 2] + c [center dot] [Sigma](La)(Lo) + d [center dot] [Sigma]H(La) =[Sigma]T(La) a [center dot] [Sigma](Lo) + b [center dot] [Sigma](La)(Lo) + c [center dot] [Sigma](Lo)[sup 2] + d [center dot] [Sigma]H(Lo) = [Sigma]T(Lo) a[center dot] [Sigma]H + b [center dot] [Sigma]H(La) + c [center dot] [Sigma](Lo) + d [center dot] [Sigma]H[sup 2] = [Sigma]TH where n is the number of data sets. The calculation of sigma values and the solution of the set of equations have been performed by means of a personal computer. The resulting formula is: T = 57.487 [minus] 1.078 La + 0.102 Lo [minus] 0.00488H where latitude and longitude are expressed in degrees, and elevation in meters. The regional value at Ankara (latitude 39.9[degrees], longitude 32.9[degrees], elevation 894 m) is calculated as 13.5[degrees]C (the measured value at 1 m depth is 14.6[degrees]C) and at Adana.« less

Performance of photocatalyst based carbon nanodots from waste frying oil in water purification

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

Aji, Mahardika Prasetya, E-mail: mahardika190@gmail.com; Wiguna, Pradita Ajeng; Susanto,

Carbon Nanodots (C-Dots) from waste frying oil could be used as a photocatalyst in water purification with solar light irradiation. Performance of C-Dots as a photocatalyst was tested in the process of water purification with a given synthetic sewage methylene blue. The tested was also conducted by comparing the performance C-Dots made from frying oil, waste fryng oil as a photocatalyst and solution of methylene blue without photocatalyst C-Dots. Performance of C-Dots from waste frying oil were estimated by the results of absorbance spectrum. The results of measurement absorbance spectrum from the process of water purification with photocatalyst C-Dots showedmore » that the highest intensity at a wavelength 664 nm of methylene blue decreased. The test results showed that the performance of photocatalyst C-Dots from waste frying oil was better in water purification. This estimated that number of particles C-dots is more in waste frying oil because have experieced repeated the heating process so that the higher particles concentration make the photocatalyst process more effective. The observation of the performance C-Dots from waste frying oil as a photocatalyst in the water purification processes become important invention for solving the problems of waste and water purification.« less

The effect and fate of water-soluble carbon nanodots in maize (Zea mays L.).

PubMed

Chen, Jing; Dou, Runzhi; Yang, Zhongzhou; Wang, Xiaoping; Mao, Chuanbin; Gao, Xiang; Wang, Li

2016-08-01

In this study, the toxicity of water-soluble carbon nanodots (C-dots) to maize (Zea mays L.) and their uptake and transport in plants were investigated. After exposed in sand matrix amended with 0-2000 mg/L C-dots for 4 weeks, we found that the phytotoxicity of C-dots was concentration-dependent. C-dots at 250 and 500 mg/L showed no toxicity to maize. However, 1000 and 2000 mg/L C-dots significantly reduced the fresh weight of root by 57% and 68%, and decreased the shoot fresh weight by 38% and 72%, respectively. Moreover, in maize roots, the exposure of C-dots at 2000 mg/L significantly increased the H2O2 content and lipid peroxidation (6.5 and 1.65 times higher, respectively), as well as, the antioxidant enzymes activities, up to 2, 1.5, 1.9 and 1.9 times higher for catalase, ascorbate peroxidase, guaiacol peroxidase and superoxide dismutase, respectively. On the other hand, C-dots were observed in detached root-cap cells, cortex and vascular bundle of roots and mesophyll cells of leaves through fluorescence microscopy analysis, suggesting that C-dots were absorbed and translocated systemically in maize. Remarkably, a certain amount of C-dots were excreted out from leaf blade. To our knowledge, this is the first study combined phenotypic observation with physiologic responses and bioaccumulation and translocation analysis of C-dots to investigate their effect and fate in maize.

Liquid nitrogen-assisted synthesis of fluorescent carbon dots from Blueberry and their performance in Fe3+ detection

NASA Astrophysics Data System (ADS)

Aslandaş, Ayşe Merve; Balcı, Neslihan; Arık, Mustafa; Şakiroğlu, Halis; Onganer, Yavuz; Meral, Kadem

2015-11-01

Fluorescent carbon dots (C-dots) were synthesized by a facile method containing liquid N2 treatment and centrifuge processes. The photophysical properties of the C-dots in an aqueous solution were examined at various conditions such as concentration, temperature, pH and excitation wavelength by using UV-vis absorption, fluorescence and time-resolved fluorescence spectroscopies. The C-dots emitted a broad fluorescence between approximately 350-550 nm and their fluorescence was tuned by changing excitation wavelength. The as-prepared C-dots were applied to Fe3+ detection from aqueous solution. Spectroscopic data revealed that the as-prepared C-dots were used to detect Fe3+ in the range of 12.5 μM to 100 μM as a fluorescence sensor.

Characterization of Asia 1 sdAb from Camels Bactrianus (C. bactrianus) and Conjugation with Quantum Dots for Imaging FMDV in BHK-21 Cells

PubMed Central

Shang, Youjun; Sun, Shiqi; Zhou, Guangqing; Jin, Ye; Tian, Hong; Wu, Jinyan; Liu, Xiangtao

2013-01-01

Foot-and-mouth disease (FMD), caused by FMD virus (FMDV), is a highly contagious viral disease affecting cloven-hoofed animals. Camelids have a unique immunoglobulin profile, with the smallest functional heavy-chain antibodies (sdAb or VHH) naturally devoid of light chains with antigen-binding capacity. We screened and characterized five sdAbs against FMDV by immunized library from C. bactrianus with Asia 1 virus-like particles (VLPs). Three of five recombinant sdAbs were stably expressed in E.coli, remained highly soluble, and were serotype-specific for VP1 protein of FMDV Asia 1 by ELISA. These failed to completely neutralize the Asia 1 virus. According to the KD value of binding affinity to three sdAbs, which ranged from 0.44 to 0.71 nm by SPR, sdAb-C6 was selected and conjugated with Zn/CdSe quantum dots (QDs) to form a QDs-C6 probe, which was used to trace and image the subcellular location of FMDV in BHK-21 cells. The results show that FMD virions were observed from 3 h.p.i., and most of virions were distributed on one side of the nucleus in the cytoplasm. We demonstrate the utility of sdAbs as functionalized QDs are powerful tools for FMDV research. PMID:23737944

Understanding the Capsanthin Tails in Regulating the Hydrophilic-Lipophilic Balance of Carbon Dots for a Rapid Crossing Cell Membrane.

PubMed

Chen, Jing; Zhang, Xiang; Zhang, Ye; Wang, Wei; Li, Shuya; Wang, Yucai; Hu, Mengyue; Liu, Li; Bi, Hong

2017-10-03

Here we use natural Chinese paprika to prepare a new kind of amphiphilic carbon dot (A-Dot) that exhibits bright, multicolored fluorescence and contains hydrophilic groups as well as lipophilic capsanthin tails on the surface. It is found that the capsanthin tails in a phospholipid-like structure can promote cell internalization of the A-Dots via crossing cell membranes rapidly in an energy-independent fashion. Compared to highly hydrophilic carbon dots (H-Dots), a control sample prepared from the microwave thermolysis of citric acid and ethylenediamine, our synthesized A-Dots can be taken up by CHO, HeLa, and HFF cells more easily. More importantly, we develop a method to calibrate the hydrophilic-lipophilic balance (HLB) values of various kinds of carbon dots (C-Dots). HLB values of A-Dots and H-Dots are determined to be 6.4 and 18.4, respectively. Moreover, we discover that the cellular uptake efficiency of C-Dots is closely related to their HLBs, and the C-Dots with an HLB value of around 6.4 cross the cell membrane easier and faster. As we regulate the HLB value of the A-Dots from 6.4 to 15.3 by removing the capsanthin tails from their surfaces via alkali refluxing, it is found that the refluxed A-Dots can hardly cross HeLa cell membranes. Our work is an essential step toward understanding the importance of regulating the HLB values as well as the surface polarity of the C-Dots for their practical use in bioimaging and also provides a simple but effective way to judge whether the C-Dots in hand are appropriate for cell imaging.

Carbon nanodots prepared from o-phenylenediamine for sensing of Cu2+ ions in cells

NASA Astrophysics Data System (ADS)

Vedamalai, Mani; Periasamy, Arun Prakash; Wang, Chia-Wei; Tseng, Yu-Ting; Ho, Lin-Chen; Shih, Chung-Chien; Chang, Huan-Tsung

2014-10-01

A simple hydrothermal method was applied to prepare carbon nanodots (C dots) from o-phenylenediamine (OPD). The C dots exhibit photoluminescence at 567 nm when excited at 420 nm. In the presence of Cu2+ ions, the colour of C dots changes from yellow to orange, with an increased PL intensity as a result of the formation of Cu(OPD)2 complexes on the surfaces of C dots. The D-band to G-band ratios of C dots in the absence and presence of 80 nM Cu2+ ions are 1.31 and 4.75, respectively. The C dots allow the detection of Cu2+ ions with linearity over a concentration range of 2-80 nM, with a limit of detection of 1.8 nM at a signal-to-noise ratio of 3. The cell viability values of A549, MCF-10A, and MDA-MB-231 cells treated with 3 μg mL-1 of C dots are all greater than 99%, showing their great biocompatibility. Having great water dispersibility, photostability, chemical stability (against NaCl up to 0.5 M), great selectivity, and biocompatibility, the C dots have been employed for the localization of Cu2+ ions in the cancer cells (A549 cells) treated with 10 μM Cu2+ ions.A simple hydrothermal method was applied to prepare carbon nanodots (C dots) from o-phenylenediamine (OPD). The C dots exhibit photoluminescence at 567 nm when excited at 420 nm. In the presence of Cu2+ ions, the colour of C dots changes from yellow to orange, with an increased PL intensity as a result of the formation of Cu(OPD)2 complexes on the surfaces of C dots. The D-band to G-band ratios of C dots in the absence and presence of 80 nM Cu2+ ions are 1.31 and 4.75, respectively. The C dots allow the detection of Cu2+ ions with linearity over a concentration range of 2-80 nM, with a limit of detection of 1.8 nM at a signal-to-noise ratio of 3. The cell viability values of A549, MCF-10A, and MDA-MB-231 cells treated with 3 μg mL-1 of C dots are all greater than 99%, showing their great biocompatibility. Having great water dispersibility, photostability, chemical stability (against NaCl up to 0.5 M), great selectivity, and biocompatibility, the C dots have been employed for the localization of Cu2+ ions in the cancer cells (A549 cells) treated with 10 μM Cu2+ ions. Electronic supplementary information (ESI) available: XRD, FTIR, absorption, Raman scattering, fluorescence spectra, the effect of pH, photostability and cell viability results. See DOI: 10.1039/c4nr03213f

Selective Determination of Trinitrotoluene Based on Energy Transfer between Carbon Dots and Gold Nanoparticles.

PubMed

Oskoei, Yones Mosaei; Fattahi, Hassan; Hassanzadeh, Javad; Azar, Ali Mousavi

2016-01-01

A fluorescence resonance energy transfer (FRET) system between carbon dots (C-dots) and amine-capped gold nanoparticles (AuNPs) was developed for the selective determination of 2,4,6-trinitrotoluene (TNT). C-dots have an intrinsic florescence emission depending on their exciting wavelength. In the presence of AuNPs, C-dots adsorb on the Au surfaces, and NPs treat as energy acceptor, which can receive light emitted by C-dots, leading to decrease the fluorescence intensity of C-dots. Furthermore, it is observed that nitroaromatic compounds, especially TNT, could restore this fluorescence due to selective interaction with AuNPs via amine groups, and so releasing the C-dots. Based on this effect, a sensitive and selective fluorescence turn-on probe was designed for the determination of TNT. Some important factors including AuNPs and C-dot concentrations and media pH, which would affect the efficiency of the probe, were optimized. Under the optimum experimental conditions, good linear relationships in the range of 7 - 250 nmol L(-1) TNT with the detection limit of 2.2 nmol L(-1) were obtained. The proposed method was satisfactorily applied to the determination of TNT in the environmental water samples. Compared with previous reports, the developed method has relatively high sensitivity, short analysis time, low cost and ease of operation.

One-Pot Large-Scale Synthesis of Carbon Quantum Dots: Efficient Cathode Interlayers for Polymer Solar Cells.

PubMed

Yang, Yuzhao; Lin, Xiaofeng; Li, Wenlang; Ou, Jiemei; Yuan, Zhongke; Xie, Fangyan; Hong, Wei; Yu, Dingshan; Ma, Yuguang; Chi, Zhenguo; Chen, Xudong

2017-05-03

Cathode interlayers (CILs) with low-cost, low-toxicity, and excellent cathode modification ability are necessary for the large-scale industrialization of polymer solar cells (PSCs). In this contribution, we demonstrated one-pot synthesized carbon quantum dots (C-dots) with high production to serve as efficient CIL for inverted PSCs. The C-dots were synthesized by a facile, economical microwave pyrolysis in a household microwave oven within 7 min. Ultraviolet photoelectron spectroscopy (UPS) studies showed that the C-dots possessed the ability to form a dipole at the interface, resulting in the decrease of the work function (WF) of cathode. External quantum efficiency (EQE) measurements and 2D excitation-emission topographical maps revealed that the C-dots down-shifted the high energy near-ultraviolet light to low energy visible light to generate more photocurrent. Remarkably improvement of power conversion efficiency (PCE) was attained by incorporation of C-dots as CIL. The PCE was boosted up from 4.14% to 8.13% with C-dots as CIL, which is one of the best efficiency for i-PSCs used carbon based materials as interlayers. These results demonstrated that C-dots can be a potential candidate for future low cost and large area PSCs producing.

Bottom-up electrochemical preparation of solid-state carbon nanodots directly from nitriles/ionic liquids using carbon-free electrodes and the applications in specific ferric ion detection and cell imaging

NASA Astrophysics Data System (ADS)

Niu, Fushuang; Xu, Yuanhong; Liu, Mengli; Sun, Jing; Guo, Pengran; Liu, Jingquan

2016-03-01

Carbon nanodots (C-dots), a new type of potential alternative to conventional semiconductor quantum dots, have attracted numerous attentions in various applications including bio-chemical sensing, cell imaging, etc., due to their chemical inertness, low toxicity and flexible functionalization. Various methods including electrochemical (EC) methods have been reported for the synthesis of C-dots. However, complex procedures and/or carbon source-containing electrodes are often required. Herein, solid-state C-dots were simply prepared by bottom-up EC carbonization of nitriles (e.g. acetonitrile) in the presence of an ionic liquid [e.g. 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6)], using carbon-free electrodes. Due to the positive charges of BMIM+ on the C-dots, the final products presented in a precipitate form on the cathode, and the unreacted nitriles and BMIMPF6 can be easily removed by simple vacuum filtration. The as-prepared solid-state C-dots can be well dispersed in an aqueous medium with excellent photoluminescence properties. The average size of the C-dots was found to be 3.02 +/- 0.12 nm as evidenced by transmission electron microscopy. Other techniques such as UV-vis spectroscopy, fluorescence spectroscopy, X-ray photoelectron spectroscopy and atomic force microscopy were applied for the characterization of the C-dots and to analyze the possible generation mechanism. These C-dots have been successfully applied in efficient cell imaging and specific ferric ion detection.Carbon nanodots (C-dots), a new type of potential alternative to conventional semiconductor quantum dots, have attracted numerous attentions in various applications including bio-chemical sensing, cell imaging, etc., due to their chemical inertness, low toxicity and flexible functionalization. Various methods including electrochemical (EC) methods have been reported for the synthesis of C-dots. However, complex procedures and/or carbon source-containing electrodes are often required. Herein, solid-state C-dots were simply prepared by bottom-up EC carbonization of nitriles (e.g. acetonitrile) in the presence of an ionic liquid [e.g. 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6)], using carbon-free electrodes. Due to the positive charges of BMIM+ on the C-dots, the final products presented in a precipitate form on the cathode, and the unreacted nitriles and BMIMPF6 can be easily removed by simple vacuum filtration. The as-prepared solid-state C-dots can be well dispersed in an aqueous medium with excellent photoluminescence properties. The average size of the C-dots was found to be 3.02 +/- 0.12 nm as evidenced by transmission electron microscopy. Other techniques such as UV-vis spectroscopy, fluorescence spectroscopy, X-ray photoelectron spectroscopy and atomic force microscopy were applied for the characterization of the C-dots and to analyze the possible generation mechanism. These C-dots have been successfully applied in efficient cell imaging and specific ferric ion detection. Electronic supplementary information (ESI) available: Fig. S1. TEM image of the products generated via an electrochemical method using pure BMIMBF4 aqueous solution as the electrolyte; Fig. S2. TEM and HRTEM (inset) images of the water-dispersed solution of C-dots generated from the EC process using electrolytes with a BMIMPF6/3-methylaminopropionitrile volume ratio of 1 : 9 Fig. S3. The effect of pH on the fluorescence intensity (I) of the C-dots; experimental details for detection of Fe3+ in tap water; Fig. S4. Calibration curve for detection of Fe3+ in tap water using the standard addition method. See DOI: 10.1039/c6nr00023a

Electron paramagnetic resonance of natural and gamma-irradiated alunite and kaolin mineral powders

NASA Astrophysics Data System (ADS)

Koksal, F.; Koseoglu, R.; Saka, I.; Basaran, E.; Sener, F.

2004-06-01

Natural alunite and kaolin minerals obtained from West Anatolia were investigated by electron paramagnetic resonance (EPR) in natural and gamma-irradiated states at room temperature and at 113 K. The paramagnetic centres at ambient temperature in natural alunite were attributed to the (C) over dot H 2OH, (C) over dot O-3(-), (S) over dot O-2(-), (C) over dot O-2(-) and [AlO4 ](0) radicals. In natural kaolin, the paramagnetic centres were attributed to the (C) over dot O-3(-), (S) over dot O-2(-) (C) over dot O-2(-) and [AlO4](0) radicals. The gamma-irradiation does not produce any detectable effects on these radicals. At 113 K, the lines for (C) over dot H2OH could not be observed well, probably due to the anisotropic behaviour of the hyperfine interaction of the methylene protons, but the lines for [AlO4](0) centres were found to be perfectly observable at above 20 mW microwave power in both alunite and kaolin powders before and after gamma-irradiation. The EPR parameters of the observed paramagnetic centres were reported.

Carbon-dot-decorated TiO2 nanotube arrays used for photo/voltage-induced organic pollutant degradation and the inactivation of bacteria

NASA Astrophysics Data System (ADS)

Feng, Lingyan; Sun, Hanjun; Ren, Jinsong; Qu, Xiaogang

2016-03-01

Photoluminescent carbon dots (c-dots) have recently attracted growing interest as a new member of the carbon-nanomaterial family. Here, we report for the first time that c-dot-decorated TiO2 nanotube arrays (c-dot/TiNTs) exhibit highly enhanced abilities regarding photo/voltage-induced organic pollutant degradation and bacterial inactivation. By applying UV irradiation (365 nm) or an electrochemical potential over 3 V (versus Ag/AgCl), an organic dye and a herbicide were efficiently degraded. Moreover, the inactivation of Gram-positive S. aureus and Gram-negative E. coli bacteria was realized on a c-dot/TiNT film. The c-dots were able to absorb light efficiently resulting in multiple exciton generation and also a reduction in the recombination of the e-/h+ pair produced in c-dot/TiNT film during photo/voltage-induced degradation. It was also possible to readily regenerate the surface using ultraviolet light irradiation, leaving the whole film structure undamaged and with high reproducibility and stability.

Time to sputum conversion in smear positive pulmonary TB patients on category I DOTS and factors delaying it.

PubMed

Parikh, Raunak; Nataraj, Gita; Kanade, Swapna; Khatri, Vijay; Mehta, Preeti

2012-08-01

Sputum smear positive pulmonary tuberculosis patients expel infectious viable bacilli for a period following commencement of treatment. Patients on Directly Observed Treatment Shortcourse (DOTS) receive intermittent therapy with multidrug regimen. To determine the time to sputum smear and culture conversion following initiation of DOTS treatment and study the factors that influence it. A prospective study was undertaken at a tertiary care teaching hospital in Mumbai over a one year period on a cohort of 71 sputum smear positive patients on Category I DOTS treatment. Patients were followed up weekly for upto 20 weeks or until they underwent smear and culture conversion whichever was earlier. At each follow up, specimens were collected and processed for microscopy and culture using standard protocol. 60/71 [84.55%] patients completed the study. 56/60 [93.3%] patients underwent sputum smear and culture conversion. The median time to smear and culture conversion was end of 5th week [day 35] and 6 1/2 weeks [day 45] respectively. Univariate and stepwise regression analysis showed that patients who had cavitatory disease, high pretreatment smear grade and a past history of tuberculosis were more likely to undergo delayed or nonconversion [P < 0.05]. The time to sputum smear and culture conversion under DOTS is similar to previous antituberculosis regimens. Since viable bacilli continue to be expelled for upto two months, infection control measures should be maintained for such time. Patients with cavitatory disease, high pretreatment smear grade or a past history of tuberculosis need to be monitored more closely.

Quantum Dots

NASA Astrophysics Data System (ADS)

Tartakovskii, Alexander

2012-07-01

Part I. Nanostructure Design and Structural Properties of Epitaxially Grown Quantum Dots and Nanowires: 1. Growth of III/V semiconductor quantum dots C. Schneider, S. Hofling and A. Forchel; 2. Single semiconductor quantum dots in nanowires: growth, optics, and devices M. E. Reimer, N. Akopian, M. Barkelid, G. Bulgarini, R. Heeres, M. Hocevar, B. J. Witek, E. Bakkers and V. Zwiller; 3. Atomic scale analysis of self-assembled quantum dots by cross-sectional scanning tunneling microscopy and atom probe tomography J. G. Keizer and P. M. Koenraad; Part II. Manipulation of Individual Quantum States in Quantum Dots Using Optical Techniques: 4. Studies of the hole spin in self-assembled quantum dots using optical techniques B. D. Gerardot and R. J. Warburton; 5. Resonance fluorescence from a single quantum dot A. N. Vamivakas, C. Matthiesen, Y. Zhao, C.-Y. Lu and M. Atature; 6. Coherent control of quantum dot excitons using ultra-fast optical techniques A. J. Ramsay and A. M. Fox; 7. Optical probing of holes in quantum dot molecules: structure, symmetry, and spin M. F. Doty and J. I. Climente; Part III. Optical Properties of Quantum Dots in Photonic Cavities and Plasmon-Coupled Dots: 8. Deterministic light-matter coupling using single quantum dots P. Senellart; 9. Quantum dots in photonic crystal cavities A. Faraon, D. Englund, I. Fushman, A. Majumdar and J. Vukovic; 10. Photon statistics in quantum dot micropillar emission M. Asmann and M. Bayer; 11. Nanoplasmonics with colloidal quantum dots V. Temnov and U. Woggon; Part IV. Quantum Dot Nano-Laboratory: Magnetic Ions and Nuclear Spins in a Dot: 12. Dynamics and optical control of an individual Mn spin in a quantum dot L. Besombes, C. Le Gall, H. Boukari and H. Mariette; 13. Optical spectroscopy of InAs/GaAs quantum dots doped with a single Mn atom O. Krebs and A. Lemaitre; 14. Nuclear spin effects in quantum dot optics B. Urbaszek, B. Eble, T. Amand and X. Marie; Part V. Electron Transport in Quantum Dots Fabricated by Lithographic Techniques: III-V Semiconductors and Carbon: 15. Electrically controlling single spin coherence in semiconductor nanostructures Y. Dovzhenko, K. Wang, M. D. Schroer and J. R. Petta; 16. Theory of electron and nuclear spins in III-V semiconductor and carbon-based dots H. Ribeiro and G. Burkard; 17. Graphene quantum dots: transport experiments and local imaging S. Schnez, J. Guettinger, F. Molitor, C. Stampfer, M. Huefner, T. Ihn and K. Ensslin; Part VI. Single Dots for Future Telecommunications Applications: 18. Electrically operated entangled light sources based on quantum dots R. M. Stevenson, A. J. Bennett and A. J. Shields; 19. Deterministic single quantum dot cavities at telecommunication wavelengths D. Dalacu, K. Mnaymneh, J. Lapointe, G. C. Aers, P. J. Poole, R. L. Williams and S. Hughes; Index.

Preparation of carbon quantum dots based high photostability luminescent membranes.

PubMed

Zhao, Jinxing; Liu, Cui; Li, Yunchuan; Liang, Jiyuan; Liu, Jiyan; Qian, Tonghui; Ding, Jianjun; Cao, Yuan-Cheng

2017-06-01

Urethane acrylate (UA) was used to prepare carbon quantum dots (C-dots) luminescent membranes and the resultants were examined with FT-IR, mechanical strength, scanning electron microscope (SEM) and quantum yields (QYs). FT-IR results showed the polyurethane acrylate (PUA) prepolymer -C = C-vibration at 1101 cm -1 disappeared but there was strong vibration at1687cm -1 which was contributed from the-C = O groups in cross-linking PUA. Mechanical strength results showed that the different quantity of C-dots loadings and UV-curing time affect the strength. SEM observations on the cross-sections of the membranes are uniform and have no structural defects, which prove that the C-dots are compatible with the water-soluble PUA resin. The C-dot loading was increased from 0 to 1 g, the maximum tensile stress was nearly 2.67 MPa, but the tensile strain was decreased from 23.4% to 15.1% and 7.2% respectively. QYs results showed that the C-dots in the membrane were stable after 120 h continuous irradiation. Therefore, the C-dots photoluminescent film is the promising material for the flexible devices in the future applications. Copyright © 2016 John Wiley & Sons, Ltd.

Co-reductive fabrication of carbon nanodots with high quantum yield for bioimaging of bacteria

PubMed Central

Wang, Jiajun; Liu, Xia; Milcovich, Gesmi; Chen, Tzu-Yu; Durack, Edel; Mallen, Sarah; Ruan, Yongming

2018-01-01

A simple and straightforward synthetic approach for carbon nanodots (C-dots) is proposed. The strategy is based on a one-step hydrothermal chemical reduction with thiourea and urea, leading to high quantum yield C-dots. The obtained C-dots are well-dispersed with a uniform size and a graphite-like structure. A synergistic reduction mechanism was investigated using Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The findings show that using both thiourea and urea during the one-pot synthesis enhances the luminescence of the generated C-dots. Moreover, the prepared C-dots have a high distribution of functional groups on their surface. In this work, C-dots proved to be a suitable nanomaterial for imaging of bacteria and exhibit potential for application in bioimaging thanks to their low cytotoxicity. PMID:29441259

Carbon dots: emerging theranostic nanoarchitectures.

PubMed

Mishra, Vijay; Patil, Akshay; Thakur, Sourav; Kesharwani, Prashant

2018-06-01

Nanotechnology has gained significant interest from biomedical and analytical researchers in recent years. Carbon dots (C-dots), a new member of the carbon nanomaterial family, are spherical, nontoxic, biocompatible, and discrete particles less than 10nm in diameter. Research interest has focused on C-dots because of their ultra-compact nanosize, favorable biocompatibility, outstanding photoluminescence, superior electron transfer ability, and versatile surface engineering properties. C-dots show significant potential for use in cellular imaging, biosensing, targeted drug delivery, and other biomedical applications. Here we discuss C-dots, in terms of their physicochemical properties, fabrication techniques, toxicity issues, surface engineering and biomedical potential in drug delivery, targeting as well as bioimaging. Copyright © 2018 Elsevier Ltd. All rights reserved.

Growth and characterization of single crystal rocksalt LaAs using LuAs barrier layers

NASA Astrophysics Data System (ADS)

Krivoy, E. M.; Rahimi, S.; Nair, H. P.; Salas, R.; Maddox, S. J.; Ironside, D. J.; Jiang, Y.; Dasika, V. D.; Ferrer, D. A.; Kelp, G.; Shvets, G.; Akinwande, D.; Bank, S. R.

2012-11-01

We demonstrate the growth of high-quality, single crystal, rocksalt LaAs on III-V substrates; employing thin well-behaved LuAs barriers layers at the III-V/LaAs interfaces to suppress nucleation of other LaAs phases, interfacial reactions between GaAs and LaAs, and polycrystalline LaAs growth. This method enables growth of single crystal epitaxial rocksalt LaAs with enhanced structural and electrical properties. Temperature-dependent resistivity and optical reflectivity measurements suggest that epitaxial LaAs is semimetallic, consistent with bandstructure calculations in literature. LaAs exhibits distinct electrical and optical properties, as compared with previously reported rare-earth arsenide materials, with a room-temperature resistivity of ˜459 μΩ-cm and an optical transmission window >50% between ˜3-5 μm.

Mode-locked Er-doped fiber laser based on PbS/CdS core/shell quantum dots as saturable absorber.

PubMed

Ming, Na; Tao, Shina; Yang, Wenqing; Chen, Qingyun; Sun, Ruyi; Wang, Chang; Wang, Shuyun; Man, Baoyuan; Zhang, Huanian

2018-04-02

Previously, PbS/CdS core/shell quantum dots with excellent optical properties have been widely used as light-harvesting materials in solar cell and biomarkers in bio-medicine. However, the nonlinear absorption characteristics of PbS/CdS core/shell quantum dots have been rarely investigated. In this work, PbS/CdS core/shell quantum dots were successfully employed as nonlinear saturable absorber (SA) for demonstrating a mode-locked Er-doped fiber laser. Based on a film-type SA, which was prepared by incorporating the quantum dots with the polyvinyl alcohol (PVA), mode-locked Er-doped operation with a pulse width of 54 ps and a maximum average output power of 2.71 mW at the repetition rate of 3.302 MHz was obtained. Our long-time stable results indicate that the CdS shell can effectively protect the PbS core from the effect of photo-oxidation and PbS/CdS core/shell quantum dots were efficient SA candidates for demonstrating pulse fiber lasers due to its tunable absorption peak and excellent saturable absorption properties.

Discovery of a 105-ms X-ray Pulsar in Kesteven-79: On the Nature of Compact Central Objects in Supernova Remnants

NASA Technical Reports Server (NTRS)

Gotthelf, E. V.; Halpern, J. P.; Seward, F. D.

2005-01-01

We report the discovery of 105-ms X-ray pulsations from the compact central object (CCO) in the supernova remnant \\snr\\ using data acquired with the {\\it Newton X-Ray Multi-Mirror Mission). Using two observations of the pulsar taken 6-days apart we derive an upper limit on its spin-down rate of $\\dot P < 9 \\times 10"{-14}$-s-${-l)$,a nd find no evidence for binary orbital motion. The implied energy loss rate is $\\dot E < 3 \\times 10A{36)$-ergs-s$A{-1)$, polar magnetic field strength is $B-{\\rm p) < 3 \\times 10A{12)$-G, and spin-down age is $\\tau > 18.5$-kyr. The latter exceeds the remnant's estimated age, suggesting that the pulsar was born spinning near its current period. The X-ray spectrum of \\psr\\ is best characterized as a blackbody of temperature $kT {BB) =, 0.43\\pm0.02$ keV, radius $R-{BB) \\approx 1.3$-km, and $I{\\rm bol) = 5.2 \\times 10A{33)$ ergs-sSA{-1)$ at $d = 7.1$-kpc. The sinusoidal light curve is modulated with a pulsed fraction of $>45\\%$, suggestive of a small hot spot on the surface of the rotating neutron star. The lack of a discernible pulsar wind nebula is consistent with an interpretation of \\psr\\ as a rotation-powered pulsar whose spin-down luminosity falls below the empirical threshold for generating bright wind nebulae, $\\dot E-{\\rm c) = 4 \\times 10A{36)$-ergs-sSA{-I)$. The age discrepancy suggests that its $\\dot E$ has always been below $\\dot E c$, perhaps a distinguishing property of the CCOs. Alternatively, the X-ray spectrum of \\psr\\ suggests a low-luminosity AXP, but the weak inferred $B-{\\rm p)$ field is incompatible with a magnetar theory of its X-ray luminosity. The ordinary spin parameters discovered from \\psr\\ highlight the inability of existing theories to explain the high luminosities and temperatures of CCO thermal X-ray spectra.

49 CFR Appendix C to Part 40 - DOT Drug Testing Semi-Annual Laboratory Report to DOT

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 1 2013-10-01 2013-10-01 false DOT Drug Testing Semi-Annual Laboratory Report to... TRANSPORTATION WORKPLACE DRUG AND ALCOHOL TESTING PROGRAMS Pt. 40, App. C Appendix C to Part 40—DOT Drug Testing... of Drug and Alcohol Policy and Compliance, W62-300, 1200 New Jersey Avenue, SE., Washington, DC 20590...

49 CFR Appendix C to Part 40 - DOT Drug Testing Semi-Annual Laboratory Report to DOT

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 1 2010-10-01 2010-10-01 false DOT Drug Testing Semi-Annual Laboratory Report to... TRANSPORTATION WORKPLACE DRUG AND ALCOHOL TESTING PROGRAMS Pt. 40, App. C Appendix C to Part 40—DOT Drug Testing... of Drug and Alcohol Policy and Compliance, W62-300, 1200 New Jersey Avenue, SE., Washington, DC 20590...

49 CFR Appendix C to Part 40 - DOT Drug Testing Semi-Annual Laboratory Report to DOT

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 1 2012-10-01 2012-10-01 false DOT Drug Testing Semi-Annual Laboratory Report to... TRANSPORTATION WORKPLACE DRUG AND ALCOHOL TESTING PROGRAMS Pt. 40, App. C Appendix C to Part 40—DOT Drug Testing... of Drug and Alcohol Policy and Compliance, W62-300, 1200 New Jersey Avenue, SE., Washington, DC 20590...

49 CFR Appendix C to Part 40 - DOT Drug Testing Semi-Annual Laboratory Report to DOT

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 1 2014-10-01 2014-10-01 false DOT Drug Testing Semi-Annual Laboratory Report to... TRANSPORTATION WORKPLACE DRUG AND ALCOHOL TESTING PROGRAMS Pt. 40, App. C Appendix C to Part 40—DOT Drug Testing... of Drug and Alcohol Policy and Compliance, W62-300, 1200 New Jersey Avenue, SE., Washington, DC 20590...

49 CFR Appendix C to Part 40 - DOT Drug Testing Semi-Annual Laboratory Report to DOT

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 1 2011-10-01 2011-10-01 false DOT Drug Testing Semi-Annual Laboratory Report to... TRANSPORTATION WORKPLACE DRUG AND ALCOHOL TESTING PROGRAMS Pt. 40, App. C Appendix C to Part 40—DOT Drug Testing... of Drug and Alcohol Policy and Compliance, W62-300, 1200 New Jersey Avenue, SE., Washington, DC 20590...

Ab Initio Reaction Kinetics of CH 3 O$$\\dot{C}$$(=O) and $$\\dot{C}$$H 2 OC(=O)H Radicals

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

Tan, Ting; Yang, Xueliang; Ju, Yiguang

The dissociation and isomerization kinetics of the methyl ester combustion intermediates methoxycarbonyl radical (CH3Omore » $$\\dot{C}$$(=O)) and (formyloxy)methyl radical ($$\\dot{C}$$H2OC(=O)H) are investigated theoretically using high-level ab initio methods and Rice–Ramsperger–Kassel–Marcus (RRKM)/master equation (ME) theory. Geometries obtained at the hybrid density functional theory (DFT) and coupled cluster singles and doubles with perturbative triples correction (CCSD(T)) levels of theory are found to be similar. We employ high-level ab initio wave function methods to refine the potential energy surface: CCSD(T), multireference singles and doubles configuration interaction (MRSDCI) with the Davidson–Silver (DS) correction, and multireference averaged coupled-pair functional (MRACPF2) theory. MRSDCI+DS and MRACPF2 capture the multiconfigurational character of transition states (TSs) and predict lower barrier heights than CCSD(T). The temperature- and pressure-dependent rate coefficients are computed using RRKM/ME theory in the temperature range 300–2500 K and a pressure range of 0.01 atm to the high-pressure limit, which are then fitted to modified Arrhenius expressions. Dissociation of CH3O$$\\dot{C}$$(=O) to $$\\dot{C}$$H3 and CO2 is predicted to be much faster than dissociating to CH3$$\\dot{O}$$ and CO, consistent with its greater exothermicity. Isomerization between CH3O$$\\dot{C}$$(=O) and $$\\dot{C}$$H2OC(=O)H is predicted to be the slowest among the studied reactions and rarely happens even at high temperature and high pressure, suggesting the decomposition pathways of the two radicals are not strongly coupled. The predicted rate coefficients and branching fractions at finite pressures differ significantly from the corresponding high-pressure-limit results, especially at relatively high temperatures. Finally, because it is one of the most important CH3$$\\dot{O}$$ removal mechanisms under atmospheric conditions, the reaction kinetics of CH3$$\\dot{O}$$ + CO was also studied along the PES of CH3O$$\\dot{C}$$(=O); the resulting kinetics predictions are in remarkable agreement with experiments.« less

Bifunctional Carbon-Dot-WS2 Nanorods for Photothermal Therapy and Cell Imaging.

PubMed

Nandi, Sukhendu; Bhunia, Susanta Kumar; Zeiri, Leila; Pour, Maayan; Nachman, Iftach; Raichman, Daniel; Lellouche, Jean-Paul Moshe; Jelinek, Raz

2017-01-18

Multifunctional nanoparticles have attracted significant interest as biomedical vehicles, combining diagnostic, imaging, and therapeutic properties. We describe herein the construction of new nanoparticle conjugates comprising WS 2 nanorods (NRs) coupled to fluorescent carbon dots (C-dots). We show that the WS 2 -C-dot hybrids integrate the unique physical properties of the two species, specifically the photothermal activity of the WS 2 NRs upon irradiation with near-infrared (NIR) light and the excitation-dependent luminescence emission of the C-dots. The WS 2 -C-dot NRs have been shown to be non-cytotoxic and have been successfully employed for multicolour cell imaging and targeted cell killing under NIR irradiation, pointing to their potential utilization as effective therapeutic vehicles. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Blood Group Antigens on HeLa Cells shown by Mixed Agglutination

PubMed Central

Kelus, A.; Gurner, B. W.; Coombs, R. R. A.

1959-01-01

The mixed agglutination reaction has been used for investigating the presence of blood group antigens on the surface of human cervical carcinoma cells (HeLa) cultured for eight years in vitro. The H antigen was demonstrated in the absence of A and B. The MN-type antigen has been found as well as Tja. Treatment of HeLa cells with ficin greatly enhanced the reaction of anti-H and anti-Tja with the corresponding antigens on HeLa cells. The authors failed to show the following antigens: Rh(D) and Rh(c), S, P, Lea, Leb, Lua and Lub. ImagesFIG. 1FIG. 2 PMID:14405338

An investigation into the role of macromolecules of different polarity as passivating agent on the physical, chemical and structural properties of fluorescent carbon nanodots

NASA Astrophysics Data System (ADS)

Alas, Melis Ozge; Genc, Rukan

2017-05-01

In this study, comparative evaluation of fluorescent carbon nanodots (C-Dots) prepared using carob molasses was reported by screening various biocompatible macromolecules as passivating agent (PA). Incorporation of PAs with different molecular weight, polarity, and chemical structure was examined, and compared with the polyethylene glycol (PEG, Mn = 10 kN) passivated and pristine C-Dots. Not only the fluorescence properties but also many other features including size, crystal structure, colloidal conductivity, resistance to photobleaching, quantum yield, and UV-modulated surface interaction of them with the reactive oxygen species (ROS) as well as ROS production were investigated. Photoluminescence (PL) capacity of C-Dots was found to be associated with the number of surface alkyl groups and polymeric hydrogen bounding present on the C-Dot surface (increased number is associated with decreased PL) while surface conductivity of C-Dots in water was proportional to the PL intensity. More importantly, C-Dots with relatively poorer fluorescent were investigated in various organic solvents (hexane, methanol, acetone, ethanol, dimethylformamide (DMF), and DMSO). As happens with the fluorescent dyes, their PL intensities were significantly enhanced (even for pristine C-Dots) depending on the solvent characteristics. All of the C-Dots synthesized were further evaluated by means of UV-induced generation of ROS and inhibition of ROS by using H2O2 as model. In contrary to other carbonaceous nanomaterials, they did not show any ROS generation, on the contrary, they showed ROS scavenging activity that can be modulated by UV-irradiation ( λ exc = 365 nm). PEG and alginate passivated C-Dots inhibited H2O2 activity at LC50 values below 10 mg/mL.

Viscoelastic wormlike micelles formed by ionic liquid-type surfactant [C16imC8]Br towards template-assisted synthesis of CdS quantum dots.

PubMed

Hu, Yimin; Han, Jie; Ge, Lingling; Guo, Rong

2018-01-31

In this paper, viscoelastic wormlike micelles consisting of cationic liquid-type surfactant, 1-hexadecyl-3-octyl imidazolium bromide ([C 16 imC 8 ]Br), water and different additives were utilized for the synthesis of CdS quantum dots. First, the influence of different additives, such as [Cd(NH 3 ) 6 ]Cl 2 and ethanethioamid (precursors for the synthesis of CdS quantum dots), and temperature on the viscoelasticity of the [C 16 imC 8 ]Br aqueous solution was studied by dynamic and steady rheology. Furthermore, the synthesized CdS quantum dots and their photoluminescence properties were characterized by transmission electron microscopy (TEM), UV-Vis absorption spectroscopy, X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDX). In the end, the mechanism for the synthesis of CdS quantum dots in [C 16 imC 8 ]Br wormlike micelles is proposed.

Superfluid turbulence in a nonuniform circular channel

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

Murphy, P.J.

The excess dissipation due to the presence of quantized vorticity in flowing helium has been studied extensively. The success of the microscopic theory proposed by Schwarz in describing many properties of this dissipation led to a belief that the major aspects of the problem had been understood at the microscopic level. The experiment of Kafkalidis and Tough demonstrated that a weak one dimensional nonuniformity in the flow field led to a dramatic departure between the observed behavior and the predictions of the Schwarz theory using the local uniformity approximation (LUA). The research presented in this thesis was undertaken to measuremore » the dissipative states for thermal counterflow with a weak two dimensional nonuniformity. The experiment of Kafkalidis and Tough used a flow channel with a high aspect ratio. Such channels are known to exhibit only one state of superfluid turbulence. In this research the channel is circular in cross section and shows two distinct turbulent states (T-I and T-II). This experiment demonstrates that there is no difference in the excess dissipation for flows that are either converging or diverging. The T-I state is described by the same parameters as the T-I state in uniform channels. The turbulence exhibits front behavior at the transition between states. These conclusions are consistent with the LUA. The T-II state is at variance with the LUA, but is consistent with the results found in the Kafkalidis and Tough experiment.« less

Photoluminescence response of colloidal quantum dots on VO2 film across metal to insulator transition

PubMed Central

2014-01-01

We have proposed a method to probe metal to insulator transition in VO2 measuring photoluminescence response of colloidal quantum dots deposited on the VO2 film. In addition to linear luminescence intensity decrease with temperature that is well known for quantum dots, temperature ranges with enhanced photoluminescence changes have been found during phase transition in the oxide. Corresponding temperature derived from luminescence dependence on temperature closely correlates with that from resistance measurement during heating. The supporting reflectance data point out that photoluminescence response mimics a reflectance change in VO2 across metal to insulator transition. Time-resolved photoluminescence study did not reveal any significant change of luminescence lifetime of deposited quantum dots under metal to insulator transition. It is a strong argument in favor of the proposed explanation based on the reflectance data. PACS 71.30. + h; 73.21.La; 78.47.jd PMID:25404877

Synthesis of fluorescent carbon dots by a microwave heating process: structural characterization and cell imaging applications

NASA Astrophysics Data System (ADS)

Stefanakis, Dimitrios; Philippidis, Aggelos; Sygellou, Labrini; Filippidis, George; Ghanotakis, Demetrios; Anglos, Demetrios

2014-10-01

Two types of highly fluorescent carbon dots (C-dots) were prepared by a single-step procedure based on microwave heating citric acid and 6-aminocaproic acid or citric acid and urea in an aqueous solution. The small size of the isolated carbon dots along with their strong absorption in the UV and their excitation wavelength-dependent fluorescence render them ideal nanomaterials for biomedical applications (imaging and sensing). The structure and properties of the two types of C-dot materials were studied using a series of spectroscopic techniques. The ability of the C-dots to be internalized by HeLa cells was demonstrated via 3-photon fluorescence microscopy imaging.

Collisional dark matter and the origin of massive black holes

PubMed

Ostriker

2000-06-05

If the cosmological dark matter is primarily in the form of an elementary particle which has mass m(p) and cross section for self-interaction sigma, then seed black holes (formed in stellar collapse) will grow in a Hubble time t(H) due to accretion of the dark matter to a mass, M(H) = sqrt[IC(9)(A)t(H)(sigma/G(3)m(p)c(2))] = 7.1x10(6)(sigma/m(p))(1/2)V(9/2)(c)t(1/2)(H,15) solar masses. Here I is a numerical factor, C(A) the galactic velocity dispersion, and V(c) its rotation velocity. For the same values of ( sigma/m(p)) that are attractive with respect to other cosmological desiderata, this produces massive black holes in the (10(6)-10(9))M( middle dot in circle) range observed, with the same dependence on a V(c) seen, and with a time dependence consistent with observations. Other astrophysical consequences of collisional dark matter and tests of the idea are noted.

Photoluminescent carbon dots based on a rare 3D inorganic-organic hybrid cadmium borate crystal.

PubMed

Zhou, Kang; Zhang, Wen-Jin; Luo, Yuan-Zhang; Pan, Chun-Yang

2018-05-17

A 3D inorganic-organic hybridized skeleton cadmium borate [Cden][B5O8(OH)] (1) (en = ethylenediamine) has been solvothermally synthesized. By calcining it, specific shape carbon dots (C-dots) with abundant free radicals were observed. In addition, C-dots in the ethanol phase exhibited variable photoluminescence and showed rare turn on or off effects to Cr3+ ions and CdSe/ZnS quantum dots, but only a turn on effect to Cs+ ions and a turn off effect to CsPbBr3 quantum dots.

Comparison between DOT EIA IgM and Widal Test as early diagnosis of typhoid fever.

PubMed

Begum, Z; Hossain, M A; Musa, A K; Shamsuzzaman, A K; Mahmud, M C; Ahsan, M M; Sumona, A A; Ahmed, S; Jahan, N A; Alam, M; Begum, A

2009-01-01

A recently developed DOT enzyme immunoassay known as "Typhidot" for detecting IgM antibody against 50 KDa OMP antigen of Salmonella typhi, was evaluated on 100 clinically suspected typhoid fever cases and 40 age-sex matched controls, in the Department of Microbiology, Mymensingh Medical College during, the period from June 2006 to July 2007. Blood culture, Widal test, and DOT EIA for IgM test were performed in all patients. Among 100 clinically suspected typhoid fever cases, 35 were subsequently confirmed on the basis of positive blood culture for S. typhi and/or significant rising titre of Widal test. The DOT EIA IgM test could produce results within 1 hour. The result of the DOT EIA IgM test showed a good diagnostic value for typhoid fever. The sensitivity, specificity, positive and negative predictive value of the test was found as 91.42%, 90.00%, 88.88% and 92.30% respectively. On the other hand corresponding values for Widal test were of 42.85%, 85.00%, 71.42% and 62.96% respectively. Thus, The DOT EIA IgM seems to be a practical alternative to Widal test for early diagnosis of typhoid fever.

49 CFR Appendix C to Part 180 - Eddy Current Examination With Visual Inspection for DOT 3AL Cylinders Manufactured of Aluminum...

Code of Federal Regulations, 2013 CFR

2013-10-01

... for DOT 3AL Cylinders Manufactured of Aluminum Alloy 6351-T6 C Appendix C to Part 180 Transportation... Pt. 180, App. C Appendix C to Part 180—Eddy Current Examination With Visual Inspection for DOT 3AL... with CGA pamphlet C-6.1 (IBR; see § 171.7 of this subchapter). 3. Eddy Current Equipment. A reference...

Fine Structure of Trious and Excitons in Single GaAs Quantum Dots

DTIC Science & Technology

2002-08-30

RAPID COMMUNICATIONS PHYSICAL REVIEW B 66, 081310~R! ~2002!Fine structure of trions and excitons in single GaAs quantum dots J. G. Tischler, A. S ...fine structure of single localized excitons and trions. DOI: 10.1103/PhysRevB.66.081310 PACS number~ s !: 78.67.Hc, 73.21.2b, 71.35.2yAlthough the...AUTHOR( S ) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME( S ) AND ADDRESS(ES) Naval Research Laboratory

Tuneable light-emitting carbon-dot/polymer flexible films prepared through one-pot synthesis

NASA Astrophysics Data System (ADS)

Bhunia, Susanta Kumar; Nandi, Sukhendu; Shikler, Rafi; Jelinek, Raz

2016-02-01

Development of efficient, inexpensive, and environmentally-friendly light emitters, particularly devices that produce white light, have drawn intense interest due to diverse applications in the lighting industry, photonics, solar energy, and others. We present a simple strategy for the fabrication of flexible transparent films exhibiting tuneable light emission through one-pot synthesis of polymer matrixes with embedded carbon dots assembled in situ. Importantly, different luminescence colours were produced simply by preparing C-dot/polymer films using carbon precursors that yielded C-dots exhibiting distinct fluorescence emission profiles. Furthermore, mixtures of C-dot precursors could be also employed for fabricating films exhibiting different colours. In particular, we successfully produced films emitting white light with attractive properties (i.e. ``warm'' white light with a high colour rendering index) - a highly sought after goal in optical technologies.Development of efficient, inexpensive, and environmentally-friendly light emitters, particularly devices that produce white light, have drawn intense interest due to diverse applications in the lighting industry, photonics, solar energy, and others. We present a simple strategy for the fabrication of flexible transparent films exhibiting tuneable light emission through one-pot synthesis of polymer matrixes with embedded carbon dots assembled in situ. Importantly, different luminescence colours were produced simply by preparing C-dot/polymer films using carbon precursors that yielded C-dots exhibiting distinct fluorescence emission profiles. Furthermore, mixtures of C-dot precursors could be also employed for fabricating films exhibiting different colours. In particular, we successfully produced films emitting white light with attractive properties (i.e. ``warm'' white light with a high colour rendering index) - a highly sought after goal in optical technologies. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr08400h

Patients' costs and cost-effectiveness of tuberculosis treatment in DOTS and non-DOTS facilities in Rio de Janeiro, Brazil.

PubMed

Steffen, Ricardo; Menzies, Dick; Oxlade, Olivia; Pinto, Marcia; de Castro, Analia Zuleika; Monteiro, Paula; Trajman, Anete

2010-11-17

Costs of tuberculosis diagnosis and treatment may represent a significant burden for the poor and for the health system in resource-poor countries. The aim of this study was to analyze patients' costs of tuberculosis care and to estimate the incremental cost-effectiveness ratio (ICER) of the directly observed treatment (DOT) strategy per completed treatment in Rio de Janeiro, Brazil. We interviewed 218 adult patients with bacteriologically confirmed pulmonary tuberculosis. Information on direct (out-of-pocket expenses) and indirect (hours lost) costs, loss in income and costs with extra help were gathered through a questionnaire. Healthcare system additional costs due to supervision of pill-intake were calculated considering staff salaries. Effectiveness was measured by treatment completion rate. The ICER of DOT compared to self-administered therapy (SAT) was calculated. DOT increased costs during the treatment phase, while SAT increased costs in the pre-diagnostic phase, for both the patient and the health system. Treatment completion rates were 71% in SAT facilities and 79% in DOT facilities. Costs per completed treatment were US$ 194 for patients and U$ 189 for the health system in SAT facilities, compared to US$ 336 and US$ 726 in DOT facilities. The ICER was US$ 6,616 per completed DOT treatment compared to SAT. Costs incurred by TB patients are high in Rio de Janeiro, especially for those under DOT. The DOT strategy doubles patients' costs and increases by fourfold the health system costs per completed treatment. The additional costs for DOT may be one of the contributing factors to the completion rates below the targeted 85% recommended by WHO.

Adenosine-derived doped carbon dots: From an insight into effect of N/P co-doping on emission to highly sensitive picric acid sensing.

PubMed

Li, Na; Liu, Shi Gang; Fan, Yu Zhu; Ju, Yan Jun; Xiao, Na; Luo, Hong Qun; Li, Nian Bing

2018-07-12

The various synthetic routes of carbon dots (C-dots) feature a considerable step toward their potential use in chemical sensors and biotechnology. Herein, by coupling phosphorus and nitrogen element introduction, the adenosine-derived N/P co-doped C-dots with fluorescence enhancement were achieved. By separately employing adenosine, adenosine monophosphate, adenosine diphosphate, and adenosine-5'-triphosphate as precursors, the effect of N/P co-doping on the fluorescence emission is discussed in detail. The formed C-dots with adenosine monophosphate exhibited strong blue fluorescence with a high quantum yield of 33.81%. Then the C-dots were employed as a fluorescent probe and utilized to develop a fast, sensitive, and selective picric acid sensor. The fluorescence of C-dots can be quenched by picric acid immediately, giving rise to a picric acid determination down to 30 nM. The possible mechanism of fluorescence quenching was discussed, which was proved to be inner filter effect and static quenching. Moreover, this method has the potential to detect picric acid in environmental water samples. Copyright © 2018 Elsevier B.V. All rights reserved.

University Students' Conceptions about the Moon Phases. (Spanish Title: Concepciones de Estudiantes Universitários sobre Las Fases de la Luna.) Concepções de Estudantes Universitários sobre as Fases da Lua

NASA Astrophysics Data System (ADS)

de Fátima Oliveira Saraiva, Maria; da Silveira, Fernando Lang; Steffani, Maria Helena

2011-07-01

In this article we describe the development of a multiple choice test about lunar phases and analyze the results of its application to ten groups of Physics students at the UFRGS. During the improvement of the test, we noticed that the percentage of right answers about some concepts increased significantly when associated with the reformulation of the question, emphasizing the importance of being careful to avoid incorrect answers generated by unclear questions, and not by ignorance on the matter. We confirm the results of other studies that show that students have great difficulty to relate the Moon's phase with its position in the sky at given time. On the other hand, our results suggest that, in general, students of Physics understand the phenomenon of lunar phases better than the average of university students. En estese artículo se describe la elaboración de una prueba de opción múltiple sobre las fases de la Luna y se analizan los resultados de su aplicación en diez grupos de estudiantes de Física de UFRGS. Durante el mejoramiento de la prueba observamos que el porcentaje de aciertos creció considerablemente cuando considerada una nueva redacción de la pregunta, destacando el cuidado que se debe tomar a fin de evitar respuestas incorrectas generadas por preguntas poco claras y no a causa de la ignorancia de los estudiantes sobre el tema. Confirmamos los resultados de otros estudios que las mayores dificultades de los alumnos sobre el tema fases de la Luna están en relacionar la fase de la Luna con su posición en el cielo en determinado momento. Por otra parte, nuestros resultados sugieren que, en general, los estudiantes de la Física comprenden mejor el fenómeno de las fases lunares que el promedio de los estudiantes universitarios. Neste artigo descrevemos a elaboração de um teste de múltipla escolha sobre as fases da Lua e analisamos os resultados de sua aplicação em dez grupos de estudantes de Física da UFRGS. Durante o aprimoramento do teste notamos que a porcentagem de acertos a respeito de alguns conceitos teve um aumento significativo associado à reformulação da pergunta, ressaltando a importância de tomar cuidado para evitar respostas erradas geradas por perguntas pouco claras e não por ignorância do respondente sobre o assunto. Confirmamos os resultados de outros estudos de que as maiores dificuldades dos alunos sobre o tema Fases da Lua dizem respeito a relacionar a fase que a Lua apresenta com a sua posição no céu em determinada hora. Por outro lado, nossos resultados sugerem que, em geral, os estudantes de Física entendem melhor o fenômeno das fases lunares do que a média dos estudantes universitários.

Fog Bank Detector Field Tests : A Technical Summary

DOT National Transportation Integrated Search

1971-12-01

The report summarizes the results of field experiments performed at Pt. Bonita, California. The system under study, a laser LIDAR and a vertical-scanning infrared radiometer, have been discussed in detail in Report No. DOT-TSC-CG-71-3. Measurements o...

Neuromodulatory properties of fluorescent carbon dots: effect on exocytotic release, uptake and ambient level of glutamate and GABA in brain nerve terminals.

PubMed

Borisova, Tatiana; Nazarova, Anastasia; Dekaliuk, Mariia; Krisanova, Natalia; Pozdnyakova, Natalia; Borysov, Arsenii; Sivko, Roman; Demchenko, Alexander P

2015-02-01

Carbon dots (C-dots), a recently discovered class of fluorescent nano-sized particles with pure carbon core, have great bioanalytical potential. Neuroactive properties of fluorescent C-dots obtained from β-alanine by microwave heating were assessed based on the analysis of their effects on the key characteristics of GABA- and glutamatergic neurotransmission in isolated rat brain nerve terminals. It was found that C-dots (40-800 μg/ml) in dose-dependent manner: (1) decreased exocytotic release of [(3)H]GABA and L-[(14)C]glutamate; (2) reduced acidification of synaptic vesicles; (3) attenuated the initial velocity of Na(+)-dependent transporter-mediated uptake of [(3)H]GABA and L-[(14)C]glutamate; (4) increased the ambient level of the neurotransmitters, nevertheless (5) did not change significantly the potential of the plasma membrane of nerve terminals. Almost complete suppression of exocytotic release of the neurotransmitters was caused by C-dots at a concentration of 800 μg/ml. Fluorescent and neuromodulatory features combined in C-dots create base for their potential usage for labeling and visualization of key processes in nerve terminals, and also in theranostics. In addition, natural presence of carbon-containing nanoparticles in the human food chain and in the air may provoke the development of neurologic consequences. Copyright © 2014 Elsevier Ltd. All rights reserved.

SU-F-P-50: Performance Evaluation of Optically Stimulated Luminescence (OSL) NanoDots in Therapy and Imaging In-Vivo Dose Measurement During Patient Treatment

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

Kumar, S; Sarkar, B; Kaur, H

Purpose: This study was designed to evaluate the performance of optically stimulated Luminescence (OSL) nanoDots as in-vivo dosimeter. For the measurements of surface doses as well as scattered plus leakage doses, nanoDots were used during the setup verification as well as during the treatment delivery. Methods: For a total seven patients undergoing radiotherapy by volumetric modulated arc therapy, surface doses from image guidance and scattered plus leakage doses from treatment delivery were measured. Two sets of calibration curves were generated – one for therapy and another for imaging. Two different nanoDots were used for imaging and therapy doses. Imaging nanoDotsmore » were placed at the isocenter only at the time of CBCT and therapy nanoDots were placed at 25 cm away from the isocenter (either in cranial or in caudal direction) only at the time of treatment delivery. During the entire course, nanoDots were placed at the same measurement points. NanoDots were read after 15 minutes of their exposure. For the next fraction, nanoDots were corrected for the residual doses from the previous fractions. Results: Measured surface doses during imaging were 0.14±0.32 cGy, 0.11±0.04 cGy, 0.12±0.53 cGy, 0.04±0.02 cGy, 0.13±0.23 cGy, 0.11±0.43 cGy, 0.10±0.04 cGy with overall mean dose of 0.08±0.1 cGy. Measured doses during treatment delivery, indicative of scattered and leakage dose, were 0.84±0.43 cGy, 1.3±0.4 cGy, 1.4±0.4 cGy, 0.18±0.48 cGy, 0.78±0.29 cGy, 0.27±0.08 cGy, 0.78±0.07 cGy with overall mean dose of 0.61±1.3 cGy. Conclusion: This dosimeter can be used as supplementary unit to verify the doses. No change in the prescription is recommended based on nanoDots measurement. This study is on-going therefore we are presenting only mere number of patients. A large volume data will be presented after completion of the study with proper statistical analysis.« less

Technical Evaluation of Metal Detectors for Concealed Weapons (Supplement 1)

DOT National Transportation Integrated Search

1972-04-01

This document augments the classification and technical evaluation of Commercial Metal Detectors presented in Report No. DOT-TSC-OST-71-15, June 1971. Data based on extensive laboratory tests are presented on two hand-held models and two walk-through...

Algae biomass as a precursor for synthesis of nitrogen-and sulfur-co-doped carbon dots: A better probe in Arabidopsis guard cells and root tissues.

PubMed

Zhang, Che; Xiao, Yumei; Ma, Yongqiang; Li, Baoming; Liu, Zhidan; Lu, Cheng; Liu, Xue; Wei, Yao; Zhu, Zhangbing; Zhang, Yuanhui

2017-09-01

The challenge of controlling algal blooms and reusing algal biomass remain unsolved worldwide. We introduce a facile method to reuse Nannochloropsis biocrude oil (NBO) for the synthesis of nitrogen and sulfur co-doped carbon dots (N-S-C-dots). N-S-C-dots can pass through the heavily thickened wall of mature Arabidopsis thaliana (A. thaliana) guard cells because of high solubility and excellent biocompatibility. N-S-C-dots exhibit multicolor luminescence and could effectively reduce the interference of autofluorescence in plant cells by changing filters. Bioimaging of root tissues reveals that 2 major factors affect the transmission of N-S-C-dots: high osmotic pressure and intensity of cellular metabolism. This study highlights the potential application of CDs for bioimaging in plant cells and demonstrates the significance of investigating the reuse of algal biomass. Copyright © 2017. Published by Elsevier B.V.

Resonant energy transfer and trace-level sensing using branched Ag-rod-supported carbon dots

NASA Astrophysics Data System (ADS)

Nair, Radhika V.; Arya, M.; Vijayan, C.

2018-05-01

We report on the resonant energy transfer in branched Ag rod-supported carbon dots (C-dots) and its applications for the trace-level sensing of highly reactive oxygen species and organic pollutants based on surface plasmon enhanced energy transfer (SPEET) and surface enhanced Raman spectroscopy (SERS). The branched morphology of Ag is found to significantly enhance visible light absorption and thus increases the spectral overlap with C-dot emission. In addition, branched morphology results in the formation of a large number of plasmonic hotspots and efficient propagation of plasmons through the interconnections, as also supported by finite-difference time-domain simulations. Branched Ag-rod—C-dot composite is found to be able to detect 0.02 µM of hydrogen peroxide based on SPEET. The efficient transfer of electrons from C-dots to the Ag rod enhances the SERS efficiency of Ag resulting in an enhancement factor of the order of 108 and enables the composite to detect 10‑10 M of the organic pollutant Rhodamine 6G.

Non-enzymatic-browning-reaction: a versatile route for production of nitrogen-doped carbon dots with tunable multicolor luminescent display.

PubMed

Wei, Weili; Xu, Can; Wu, Li; Wang, Jiasi; Ren, Jinsong; Qu, Xiaogang

2014-01-06

The non-enzymatic browning, namely Maillard reaction is commonly invoked to account for abiotic chemical transformations of organic matter. Here we report a new reaction pathway via the Maillard reaction to systematically synthesize a series of nitrogen-doped carbon dots (C-dots) with superhigh quantum yield (QY) and tunable multicolor luminescent displayment. The starting materials are glucose and the serial amino acid analogues which allow systemically controlling luminescent and physicochemical properties of C-dots at will. Unexpectedly, the as-prepared C-dots possess bright photoluminescence with QY up to 69.1% which is almost the highest ever reported, favorable biocompatibility, excellent aqueous and nonaqueous dispersibility, ultrahigh photostability, and readily functionalization. We have demonstrated that they are particularly suitable for multicolor luminescent display and long-term and real-time cellular imaging. Furthermore, the methodology is readily scalable to large yield, and can provide sufficient amount of C-dots for practical demands.

Non-Enzymatic-Browning-Reaction: A Versatile Route for Production of Nitrogen-Doped Carbon Dots with Tunable Multicolor Luminescent Display

NASA Astrophysics Data System (ADS)

Wei, Weili; Xu, Can; Wu, Li; Wang, Jiasi; Ren, Jinsong; Qu, Xiaogang

2014-01-01

The non-enzymatic browning, namely Maillard reaction is commonly invoked to account for abiotic chemical transformations of organic matter. Here we report a new reaction pathway via the Maillard reaction to systematically synthesize a series of nitrogen-doped carbon dots (C-dots) with superhigh quantum yield (QY) and tunable multicolor luminescent displayment. The starting materials are glucose and the serial amino acid analogues which allow systemically controlling luminescent and physicochemical properties of C-dots at will. Unexpectedly, the as-prepared C-dots possess bright photoluminescence with QY up to 69.1% which is almost the highest ever reported, favorable biocompatibility, excellent aqueous and nonaqueous dispersibility, ultrahigh photostability, and readily functionalization. We have demonstrated that they are particularly suitable for multicolor luminescent display and long-term and real-time cellular imaging. Furthermore, the methodology is readily scalable to large yield, and can provide sufficient amount of C-dots for practical demands.

Sol-Gel Chemistry for Carbon Dots.

PubMed

Malfatti, Luca; Innocenzi, Plinio

2018-03-14

Carbon dots are an emerging class of carbon-based nanostructures produced by low-cost raw materials which exhibit a widely-tunable photoluminescence and a high quantum yield. The potential of these nanomaterials as a substitute of semiconductor quantum dots in optoelectronics and biomedicine is very high, however they need a customized chemistry to be integrated in host-guest systems or functionalized in core-shell structures. This review is focused on recent advances of the sol-gel chemistry applied to the C-dots technology. The surface modification, the fine tailoring of the chemical composition and the embedding into a complex nanostructured material are the main targets of combining sol-gel processing with C-dots chemistry. In addition, the synergistic effect of the sol-gel precursor combined with the C-dots contribute to modify the intrinsic chemo-physical properties of the dots, empowering the emission efficiency or enabling the tuning of the photoluminescence over a wide range of the visible spectrum. © 2018 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

One-step, green, and economic synthesis of water-soluble photoluminescent carbon dots by hydrothermal treatment of wheat straw, and their bio-applications in labeling, imaging, and sensing

NASA Astrophysics Data System (ADS)

Yuan, Ming; Zhong, Ruibo; Gao, Haiyang; Li, Wanrong; Yun, Xiaoling; Liu, Jingran; Zhao, Xinmin; Zhao, Guofen; Zhang, Feng

2015-11-01

The use of biomass as renewable and sustainable energy source has attracted the attention of politics and research and development (R&D) facilities around the world. Agricultural straw acts as a typical biowaste, which still needs highly effective recycling to save the biomass urgently at present. Photoluminescent carbon dots (C-dots) are novel biocompatible nanomaterials that have been proved to be produced from many carbon-abundant materials and hold great promise for the modern nanobiomedicine. In order to realize a "one-stone-two-birds" strategy, we report a green, economic, one-pot method in this article for synthesizing photoluminescent C-dots by hydrothermal treatment of wheat straw. Using X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD), we show that the as-prepared C-dots are amorphous in structure and are mainly composed of carbon. Their tiny size (<2 nm), combined with the characteristic excitation-dependent relatively bright emission, and robust photostability made the C-dots a potential biocompatible nanomaterial for bio-applications. We have experimentally demonstrated their potential applications in biomedical labeling, imaging, and sensing/detecting. The high yield (∼20%) of C-dots from wheat straw may suggest a new economic strategy for recycling biowaste.

49 CFR 571.116 - Standard No. 116; Motor vehicle brake fluids.

Code of Federal Regulations, 2010 CFR

2010-10-01

... following value for the grade indicated: (a) DOT 3: 140 °C. (284 °F.). (b) DOT 4: 155 °C. (311 °F.). (c) DOT... less than 1.5 mm2/s at 100 °C. (212 °F.) nor more than the following maximum value for the grade... according to S6.5.3 the ERBP shall not change by more than 3 °C. (5.4 °F.) plus 0.05° for each degree that...

49 CFR 571.116 - Standard No. 116; Motor vehicle brake fluids.

Code of Federal Regulations, 2011 CFR

2011-10-01

... following value for the grade indicated: (a) DOT 3: 140 °C. (284 °F.). (b) DOT 4: 155 °C. (311 °F.). (c) DOT... less than 1.5 mm2/s at 100 °C. (212 °F.) nor more than the following maximum value for the grade... according to S6.5.3 the ERBP shall not change by more than 3 °C. (5.4 °F.) plus 0.05° for each degree that...

X-ray and extreme ultraviolet spectroscopy on DIII-D

NASA Astrophysics Data System (ADS)

Victor, B. S.; Allen, S. L.; Beiersdorfer, P.; Magee, E. W.

2017-06-01

Two spectrometers were installed to measure tungsten emission in the core of DIII-D plasmas during a metal rings experimental campaign. The spectral range of the high-resolution (1340 spectral channels), variable-ruled grating X-ray and Extreme Ultraviolet Spectrometer (XEUS) extends from 10-71 dot A. The spectral range of the second spectrometer, the Long-Wavelength Extreme Ultraviolet Spectrometer (LoWEUS), measures between 31-174 dot A. Three groups of tungsten lines were identified with XEUS: W38+-W45+ from 47-63 dot A, W27+-W35+ from 45-55 dot A, and W28+-W33+ from 16-30 dot A. Emission lines from tungsten charge states W28+, W43+, W44+, and W45+ are identified and the line amplitude is presented versus time. Peak emission of W43+-W45+ occurs between core Te=2.5-3 keV, and peak emission of W28+ occurs at core Te<=1.3 keV. One group of tungsten lines, W40+-W45+, between 120-140 dot A, was identified with LoWEUS. W43+-W45+ lines measured with LoWEUS track the sawtooth cycle. Sensitivity to the sawtooth cycle and the correlation of the peak emission with core electron temperature show that these spectrometers track the on-axis tungsten emission of DIII-D plasmas.

Crystal structures of Boro-AFm and sBoro-AFt phases

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

Champenois, Jean-Baptiste; Mesbah, Adel; Clermont Universite, ENSCCF, Institut de Chimie de Clermont-Ferrand, BP 10448, F-63000 Clermont-Ferrand

2012-10-15

Crystal structures of boron-containing AFm (B-AFm) and AFt (B-AFt) phases have been solved ab-initio and refined from X-ray powder diffraction. {sup 11}B NMR and Raman spectroscopies confirm the boron local environment in both compounds: three-fold coordinated in B-AFm corresponding to HBO{sub 3}{sup 2-} species, and four-fold coordinated in B-AFt corresponding to B (OH){sub 4}{sup -} species. B-AFm crystallizes in the rhombohedral R3{sup Macron }c space group and has the 3CaO{center_dot}Al{sub 2}O{sub 3}{center_dot}CaHBO{sub 3}{center_dot}12H{sub 2}O (4CaO{center_dot}Al{sub 2}O{sub 3}{center_dot}1/2B{sub 2}O{sub 3}{center_dot}12.5H{sub 2}O, C{sub 4}AB{sub 1/2}H{sub 12.5}) general formulae with planar trigonal HBO{sub 3}{sup 2-} anions weakly bonded at the centre of themore » interlayer region. One HBO{sub 3}{sup 2-} anion is statistically distributed with two weakly bonded water molecules on the same crystallographic site. B-AFt crystallizes in the trigonal P3cl space group and has the 3CaO{center_dot}Al{sub 2}O{sub 3}{center_dot}Ca(OH){sub 2}{center_dot}2Ca(B (OH){sub 4}){sub 2}{center_dot}24H{sub 2}O (6CaO{center_dot}Al{sub 2}O{sub 3}{center_dot}2B{sub 2}O{sub 3}{center_dot}33H{sub 2}O, C{sub 6}AB{sub 2}H{sub 33}) general formulae with tetrahedral B (OH){sub 4}{sup -} anions located in the channel region of the structure. All tetrahedral anions are oriented in a unique direction, leading to a hexagonal c lattice parameter about half that of ettringite.« less

76 FR 42471 - Establishment of Class E Airspace; Brunswick, ME

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-19

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 71 [Docket No. FAA-2011-0116; Airspace Docket No. 11-ANE-1] Establishment of Class E Airspace; Brunswick, ME AGENCY: Federal Aviation Administration (FAA) DOT. ACTION: Final rule; correction. SUMMARY: This action corrects the...

75 FR 12678 - Revision of Class E Airspace; Dillingham, AK

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-17

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 71 [Docket No. FAA-2009-1055; Airspace Docket No. 09-AAL-16] Revision of Class E Airspace; Dillingham, AK AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: This action revises Class E airspace at...

75 FR 30295 - Amendment of Class E Airspace; Hoquiam, WA

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-01

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 71 [Docket No. FAA-2009-1063; Airspace Docket No. 09-ANM-22] Amendment of Class E Airspace; Hoquiam, WA AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: This action will amend existing Class E...

76 FR 14800 - Establishment of Class E Airspace; Wolfeboro, NH

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-18

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 71 [Docket No. FAA-2010-1007; Airspace Docket No. 10-ANE-109] Establishment of Class E Airspace; Wolfeboro, NH AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: This action establishes Class E Airspace...

75 FR 12975 - Establishment of Class E Airspace; Battle Mountain, NV

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-18

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 71 [Docket No. FAA-2009-1057; Airspace Docket No. 09-AWP-9] Establishment of Class E Airspace; Battle Mountain, NV AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: This action will establish Class...

Capacitively Coupled Plasma Discharge of Ionic Liquid Solutions to Synthesize Carbon Dots as Fluorescent Sensors.

PubMed

Ke, Ching-Bin; Lu, Te-Ling; Chen, Jian-Lian

2018-05-26

Oxygen and nitrogen capacitively coupled plasma (CCP) was used to irradiate mixtures of aliphatic acids in high boiling point solvents to synthesize fluorescent carbon dots (C-dots). With a high fluorescence intensity, the C-dots obtained from the O₂/CCP radiation of a 1-ethyl-3-methylimidazolium dicyanamide ionic liquid solution of citric acid were characterized with an average diameter of 8.6 nm (σ = 1.1 nm), nitrogen and oxygen bonding functionalities, excitation-independent emissions, and upconversion fluorescence. Through dialysis of the CCP-treated C-dots, two emissive surface states corresponding to their respective functionalities and emissions were identified. The fluorescence spectrum of the CCP-treated C-dots was different from that of the microwave irradiation and possessed higher intensity than that of hydrothermal pyrolysis. By evaluation of the fluorescence quenching effect on flavonoids and metal ions, the CCP-treated C-dots showed a high selectivity for quercetin and sensitivity to Hg 2+ . Based on the Perrin model, a calibration curve ( R ² = 0.9992) was established for quercetin ranging from 2.4 μM to 119 μM with an LOD (limit of detection) = 0.5 μM. The quercetin in the ethanol extract of the sun-dried peel of Citrus reticulata cv. Chachiensis was determined by a standard addition method to be 4.20 ± 0.15 mg/g with a matrix effect of 8.16%.

Enhanced photocatalytic H2-production activity of C-dots modified g-C3N4/TiO2 nanosheets composites.

PubMed

Li, Yang; Feng, Xionghan; Lu, Zhexue; Yin, Hui; Liu, Fan; Xiang, Quanjun

2018-03-01

As a new carbon-based material, carbon dots (C-dots) have got widely preference because of its excellent electronic transfer capability. In this work, a novel ternary layered C-dots/g-C 3 N 4 /TiO 2 nanosheets (CGT) composite photocatalysts were prepared by impregnation precipitation methods. The optimal ternary CGT composite samples revealed high photocatalytic hydrogen evolution rate in triethanolamine aqueous solutions, which exceeded the rate of the optimal g-C 3 N 4 /TiO 2 composite sample by a factor of 5 times. The improved photocatalytic activity is owed to the positive effects of C-dots and layered heterojunction structure of TiO 2 nanosheets and g-C 3 N 4 sheets. C-dots in the CGT composites can serve as electron reservoirs to capture the photo-induced electrons. The well-defined layered heterojunction structure of CGT provides the intimate contact and the strong interaction of anatase TiO 2 nanosheets and g-C 3 N 4 sheets via face-to-face orientation, which restrains the recombination of photogenerated charge carriers, and thus enhances the photocatalytic H 2 -production activity. Electron paramagnetic resonance and transient photocurrent response proved the strong interaction and improved interfacial charge transfer of TiO 2 nanosheets and g-C 3 N 4 sheets, respectively. The mechanism of improving the photocatalytic H 2 -evolution activity was further confirmed by time-resolved fluorescence, electron paramagnetic resonance, transient photocurrent response and electrochemical impedance spectroscopy. Copyright © 2017 Elsevier Inc. All rights reserved.

Fabrication and characterization of silicon quantum dots in Si-rich silicon carbide films.

PubMed

Chang, Geng-Rong; Ma, Fei; Ma, Dayan; Xu, Kewei

2011-12-01

Amorphous Si-rich silicon carbide films were prepared by magnetron co-sputtering and subsequently annealed at 900-1100 degrees C. After annealing at 1100 degrees C, this configuration of silicon quantum dots embedded in amorphous silicon carbide formed. X-ray photoelectron spectroscopy was used to study the chemical modulation of the films. The formation and orientation of silicon quantum dots were characterized by glancing angle X-ray diffraction, which shows that the ratio of silicon and carbon significantly influences the species of quantum dots. High-resolution transmission electron microscopy investigations directly demonstrated that the formation of silicon quantum dots is heavily dependent on the annealing temperatures and the ratio of silicon and carbide. Only the temperature of about 1100 degrees C is enough for the formation of high-density and small-size silicon quantum dots due to phase separation and thermal crystallization. Deconvolution of the first order Raman spectra shows the existence of a lower frequency peak in the range 500-505 cm(-1) corresponding to silicon quantum dots with different atom ratio of silicon and carbon.

75 FR 51661 - Amendment of the Pacific High and Low Offshore Airspace Areas; California

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-23

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 71 [Docket No. FAA-2010...; telephone: (202) 267-8783. SUPPLEMENTARY INFORMATION: History On Monday, June 7, 2010, the FAA published in...'' under Department of Transportation (DOT) Regulatory Policies and Procedures (44 FR 11034; February 26...

49 CFR 397.71 - Federal standards.

Code of Federal Regulations, 2011 CFR

2011-10-01

... accordance with this section. (vi) Exposure and other risk factors. States and Indian tribes shall define the exposure and risk factors associated with any NRHM routing designations. The distance to sensitive areas...: (i) The factors listed in paragraph (b)(9) of this section; and (ii) The DOT “Guidelines for Applying...

75 FR 24789 - Modification of Jet Route J-3; Spokane, WA

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-06

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 71 [Docket No. FAA-2010-0008; Airspace Docket No. 09-ANM-21] Modification of Jet Route J-3; Spokane, WA AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: This action modifies Jet Route J-3 by...

77 FR 54805 - Revocation of Jet Route J-528; WA

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-06

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 71 [Docket No. FAA-2012-0749; Airspace Docket No. 11-ANM-29] RIN 2120-AA66 Revocation of Jet Route J-528; WA AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: This action removes Jet Route J-528...

75 FR 66344 - Amendment of Jet Route J-93; CA

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-28

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 71 [Docket No. FAA-2010-1022; Airspace Docket No. 10-AWP-4] RIN 2120-AA66 Amendment of Jet Route J-93; CA AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of proposed rulemaking (NPRM). SUMMARY: This action...

75 FR 6320 - Proposed Amendment of Jet Route J-120; Alaska

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-09

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 71 [Docket No. FAA-2010-0007; Airspace Docket No. 09-AAL-20] RIN 2120-AA66 Proposed Amendment of Jet Route J-120; Alaska AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of proposed rulemaking (NPRM). SUMMARY: This...

75 FR 5703 - Proposed Modification of Jet Route J-3; Spokane, WA

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-04

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 71 [Docket No. FAA-2010-0008; Airspace Docket No. 09-ANM-21] Proposed Modification of Jet Route J-3; Spokane, WA AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of proposed rulemaking (NPRM). SUMMARY: This...

X-ray and extreme ultraviolet spectroscopy on DIII-D

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

Victor, Brian S.; Allen, Steve L.; Beiersdorfer, P.

Two spectrometers were installed to measure tungsten emission in the core of DIII-D plasmas during a metal rings experimental campaign. The spectral range of the high-resolution (1340 spectral channels), variable-ruled grating X-ray and Extreme Ultraviolet Spectrometer (XEUS) extends from10–71more » $$\\dot{A}$$ . The spectral range of the second spectrometer, the Long-Wavelength Extreme Ultraviolet Spectrometer (LoWEUS), measures between 31–174$$\\dot{A}$$ . Three groups of tungsten lines were identified with XEUS: W 38+-W 45+ from 47–63$$\\dot{A}$$ , W 27+-W 35+ from 45–55$$\\dot{A}$$ , and W 28+-W 33+ from 16–30$$\\dot{A}$$ . Emission lines from tungsten charge states W 28+, W 43+, W 44+, and W 45+ are identified and the line amplitude is presented versus time. Peak emission of W 43+-W 45+ occurs between core Te=2.5-3 keV, and peak emission of W28+ occurs at core Te 1:3 keV. One group of tungsten lines, W 40+-W 45+, between 120–140$$\\dot{A}$$ , was identified with LoWEUS. W 43+- W 45+ lines measured with LoWEUS track the sawtooth cycle. Furthermore, sensitivity to the sawtooth cycle and the correlation of the peak emission with core electron temperature show that these spectrometers track the on-axis tungsten emission of DIII-D plasmas.« less

X-ray and extreme ultraviolet spectroscopy on DIII-D

DOE PAGES

Victor, Brian S.; Allen, Steve L.; Beiersdorfer, P.; ...

2017-06-14

Two spectrometers were installed to measure tungsten emission in the core of DIII-D plasmas during a metal rings experimental campaign. The spectral range of the high-resolution (1340 spectral channels), variable-ruled grating X-ray and Extreme Ultraviolet Spectrometer (XEUS) extends from10–71more » $$\\dot{A}$$ . The spectral range of the second spectrometer, the Long-Wavelength Extreme Ultraviolet Spectrometer (LoWEUS), measures between 31–174$$\\dot{A}$$ . Three groups of tungsten lines were identified with XEUS: W 38+-W 45+ from 47–63$$\\dot{A}$$ , W 27+-W 35+ from 45–55$$\\dot{A}$$ , and W 28+-W 33+ from 16–30$$\\dot{A}$$ . Emission lines from tungsten charge states W 28+, W 43+, W 44+, and W 45+ are identified and the line amplitude is presented versus time. Peak emission of W 43+-W 45+ occurs between core Te=2.5-3 keV, and peak emission of W28+ occurs at core Te 1:3 keV. One group of tungsten lines, W 40+-W 45+, between 120–140$$\\dot{A}$$ , was identified with LoWEUS. W 43+- W 45+ lines measured with LoWEUS track the sawtooth cycle. Furthermore, sensitivity to the sawtooth cycle and the correlation of the peak emission with core electron temperature show that these spectrometers track the on-axis tungsten emission of DIII-D plasmas.« less

Shear Thinning Near the Critical Point of Xenon

NASA Technical Reports Server (NTRS)

Zimmerli, Gregory A.; Berg, Robert F.; Moldover, Michael R.; Yao, Minwu

2008-01-01

We measured shear thinning, a viscosity decrease ordinarily associated with complex liquids, near the critical point of xenon. The data span a wide range of reduced shear rate: 10(exp -3) < gamma-dot tau < 700, where gamma-dot tau is the shear rate scaled by the relaxation time tau of critical fluctuations. The measurements had a temperature resolution of 0.01 mK and were conducted in microgravity aboard the Space Shuttle Columbia to avoid the density stratification caused by Earth's gravity. The viscometer measured the drag on a delicate nickel screen as it oscillated in the xenon at amplitudes 3 mu,m < chi (sub 0) >430 mu, and frequencies 1 Hz < omega/2 pi < 5 Hz. To separate shear thinning from other nonlinearities, we computed the ratio of the viscous force on the screen at gamma-dot tau to the force at gamma-dot tau approximates 0: C(sub gamma) is identical with F(chi(sub 0), omega tau, gamma-dot tau )/F)(chi(sub 0, omega tau, 0). At low frequencies, (omega tau)(exp 2) < gamma-dot tau, C(sub gamma) depends only on gamma-dot tau, as predicted by dynamic critical scaling. At high frequencies, (omega tau)(exp 2) > gamma-dot tau, C(sub gamma) depends also on both x(sub 0) and omega. The data were compared with numerical calculations based on the Carreau-Yasuda relation for complex fluids: eta(gamma-dot)/eta(0)=[1+A(sub gamma)|gamma-dot tau|](exp - chi(sub eta)/3+chi(sub eta)), where chi(sub eta) =0.069 is the critical exponent for viscosity and mode-coupling theory predicts A(sub gamma) =0.121. For xenon we find A(sub gamma) =0.137 +/- 0.029, in agreement with the mode coupling value. Remarkably, the xenon data close to the critical temperature T(sub c) were independent of the cooling rate (both above and below T(sub c) and these data were symmetric about T(sub c) to within a temperature scale factor. The scale factors for the magnitude of the oscillator s response differed from those for the oscillator's phase; this suggests that the surface tension of the two-phase domains affected the drag on the screen below T(sub c).

A simple turn on fluorescent sensor for the selective detection of thiamine using coconut water derived luminescent carbon dots.

PubMed

Purbia, Rahul; Paria, Santanu

2016-05-15

In this study microwave-assisted hydrothermal method was used to prepare highly luminescent carbon dots (1-6 nm size) within a minute from tender coconut (Cocos nucifera) water. The synthesized carbon dots (C-dots) exhibit emission of blue and green lights while excited at 390 and 450 nm wavelengths, respectively. As an application, these C-dots were tested for a simple "turn on" fluorescent sensor for rapid detection of thiamine (vitamin B1). The detection of thiamine in human body is very important to prevent various diseases such as beriberi, neurological disorders, optic neuropathy, etc. The fluorescence emission intensity of C-dots quenches after addition of Cu(2+) ion and then again increases selectively (turn on) after the addition of thiamine. The fluorescence emission intensity enhancement of Cu(2+) ion modified C-dots in the presence of thiamine exhibits a linear relationship within the thiamine concentration range of 10-50 μM. The limit of detection was found to be 280 nM from this study. The selectivity of the detection was also tested in the presence of different organic molecules and inorganic ions (Ca(2+), Mg(2+), Na(+), K(+), Cl(-), SO4(2-), and NO3(-)) which are present in blood serum and urine and found to be almost no interference in the detection. Finally, to see the applicability in real samples a commercial vitamin capsule was tested and found less than 3% error in the detected concentration. The C-dots were also used for bioimaging of fungus and the results show they are also suitable for this application too. Copyright © 2015 Elsevier B.V. All rights reserved.

Effect of injection routes on the biodistribution, clearance, and tumor uptake of carbon dots.

PubMed

Huang, Xinglu; Zhang, Fan; Zhu, Lei; Choi, Ki Young; Guo, Ning; Guo, Jinxia; Tackett, Kenneth; Anilkumar, Parambath; Liu, Gang; Quan, Qimeng; Choi, Hak Soo; Niu, Gang; Sun, Ya-Ping; Lee, Seulki; Chen, Xiaoyuan

2013-07-23

The emergence of photoluminescent carbon-based nanomaterials has shown exciting potential in the development of benign nanoprobes. However, the in vivo kinetic behaviors of these particles that are necessary for clinical translation are poorly understood to date. In this study, fluorescent carbon dots (C-dots) were synthesized and the effect of three injection routes on their fate in vivo was explored by using both near-infrared fluorescence and positron emission tomography imaging techniques. We found that C-dots are efficiently and rapidly excreted from the body after all three injection routes. The clearance rate of C-dots is ranked as intravenous > intramuscular > subcutaneous. The particles had relatively low retention in the reticuloendothelial system and showed high tumor-to-background contrast. Furthermore, different injection routes also resulted in different blood clearance patterns and tumor uptakes of C-dots. These results satisfy the need for clinical translation and should promote efforts to further investigate the possibility of using carbon-based nanoprobes in a clinical setting. More broadly, we provide a testing blueprint for in vivo behavior of nanoplatforms under various injection routes, an important step forward toward safety and efficacy analysis of nanoparticles.

Carbon dots based fluorescent sensor for sensitive determination of hydroquinone.

PubMed

Ni, Pengjuan; Dai, Haichao; Li, Zhen; Sun, Yujing; Hu, Jingting; Jiang, Shu; Wang, Yilin; Li, Zhuang

2015-11-01

In this paper, a novel biosensor based on Carbon dots (C-dots) for sensitive detection of hydroquinone (H2Q) is reported. It is interesting to find that the fluorescence of the C-dots could be quenched by H2Q directly. The possible quenching mechanism is proposed, which shows that the quenching effect may be caused by the electron transfer from C-dots to oxidized H2Q-quinone. Based on the above principle, a novel C-dots based fluorescent probe has been successfully applied to detect H2Q. Under the optimal condition, detection limit down to 0.1 μM is obtained, which is far below U.S. Environmental Protection Agency estimated wastewater discharge limit of 0.5 mg/L. Moreover, the proposed method shows high selectivity for H2Q over a number of potential interfering species. Finally, several water samples spiked with H2Q are analyzed utilizing the sensing method with satisfactory recovery. The proposed method is simple with high sensitivity and excellent selectivity, which provides a new approach for the detection of various analytes that can be transformed into quinone. Copyright © 2015 Elsevier B.V. All rights reserved.

Fluorescent carbon nanodots for sensitive and selective detection of tannic acid in wines.

PubMed

Ahmed, Gaber Hashem Gaber; Laíño, Rosana Badía; Calzón, Josefa Angela García; García, Marta Elena Díaz

2015-01-01

Herein we describe an easy one step synthesis of carbon nanodots (C-dots) by thermal carbonization of 6-bromohexylboronic acid using two different amine compounds, polyethyleneglycol bis(3-aminopropyl (PEGA) and 1,2-aminopropane (DPA), at 180 °C in atmospheric oxygen. The as-synthesized C-dots were characterized by FTIR, HRTEM, NMR and fluorescence. The C-dots prepared using PEGA showed a strong emission at 440 nm with excitation at 362 nm. These C-dots exhibited analytical potential as sensing probes for tannic acid (TA) determination. pH effect, interferences, and analytical performance of the method were investigated. The method was found effective in the linear concentration range from 0.1 to 10 mg L(-1) TA achieving a limit of detection equal 0.018 mg L(-1) TA. The applicability of the method was demonstrated by direct measurements of TA in red and white wine samples. Validation of the method was achieved by spiking the wine samples with different standard TA concentrations obtaining recoveries in the range (90-112.5%). A probable mechanism by which TA quenched the C-dots fluorescence was proposed. Copyright © 2014 Elsevier B.V. All rights reserved.

Discovery of S···C≡N Intramolecular Bonding in a Thiophenylcyanoacrylate-Based Dye: Realizing Charge Transfer Pathways and Dye···TiO 2 Anchoring Characteristics for Dye-Sensitized Solar Cells

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

Cole, Jacqueline M.; Blood-Forsythe, Martin A.; Lin, Tze-Chia

Donor-pi-acceptor dyes containing thiophenyl pi-conjugated units and cyanoacrylate acceptor groups are among the best-performing organic chromophores used in dye-sensitized solar cell (DSC) applications. Yet, the molecular origins of their high photovoltaic output have remained unclear until now. This synchrotron-based X-ray diffraction study elucidates these origins for the high-performance thiophenylcyanoacrylate-based dye MK-2 (7.7% DSC device efficiency) and its molecular building block, MK-44. The crystal structures of MK-2 and MK-44 are both determined, while a high-resolution charge-density mapping of the smaller molecule was also possible, enabling the nature of its bonding to be detailed. A strong S center dot center dot centermore » dot C equivalent to N intramolecular interaction is discovered, which bears a bond critical point, thus proving that this interaction should be formally classified as a chemical bond. A topological analysis of the pi-conjugated portion of MK-44 shows that this S center dot center dot center dot C equivalent to N bonding underpins the highly efficient intramolecular charge transfer(ICT) in thiophenylcyanoacrylate dyes. This manifests as two bipartite ICT pathways bearing carboxylate and nitrile end points. In turn, these pathways dictate a preferred COO/CN anchoring mode for the dye as it adsorbs onto TiO2 surfaces, to form the dye TiO2 interface that constitutes the DSC working electrode. These results corroborate a recent proposal that all cyanoacrylate groups anchor onto TiO2 in this COO/CN binding configuration. Conformational analysis of the MK-44 and MK-2 crystal structures reveals that this S center dot center dot center dot C equivalent to N bonding will persist in MK-2. Accordingly, this newly discovered bond affords a rational explanation for the attractive photovoltaic properties of,MK-2. More generally, this study provides the first unequivocal evidence for an S center dot center dot center dot C equivalent to N interaction, confirming previous speculative assignments of such interactions in other compounds.« less

Comparação de modelos para o cálculo de perturbações orbitais devidas à maré terrestre

NASA Astrophysics Data System (ADS)

Vieira Pinto, J.; Vilhena de Moraes, R.

2003-08-01

Aplicações recentes de satélites artificiais com finalidades geodinâmicas requerem órbitas determinadas com bastante precisão. Em particular marés terrestres influenciam o potencial terrestre causando perturbações adicionais no movimento de satélites artificiais, as quais tem sido medidas por diversos processos. A atração exercida pela lua e pelo sol sobre a terra produz deslocamentos elásticos em seu interior e uma protuberância em sua superfície. O resultado é uma pequena variação na distribuição da massa na terra, consequentemente no geopotencial. As perturbações nos elementos orbitais de satélites artificiais terrestres devidas a maré terrestre podem ser estudadas a partir das equações de Lagrange, considerando-se um conveniente potencial. Por outro lado, como tem sido feito pelo IERS, as mudanças induzidas pela maré terrestre no geopotencial podem ser convenientemente modeladas como variações nos coeficientes Cnm e Snm do geopotencial. As duas teorias ainda não foram comparados para um mesmo satélite. Neste trabalho são apresentadas e comparadas as variações de longo período e seculares nas perturbações orbitais devidas à maré terrestre, calculadas por um modelo simples, o de Kozai, e pelo modelo do IERS. Resultados preliminares mostram, para os satélites SCD2 e CBERS1, e para a Lua em movimento elíptico e precessionando, as perturbações seculares no argumento do perigeu e na longitude do nodo ascendente.

Direct chemiluminescence of carbon dots induced by potassium ferricyanide and its analytical application

NASA Astrophysics Data System (ADS)

Amjadi, Mohammad; Manzoori, Jamshid L.; Hallaj, Tooba; Sorouraddin, Mohammad H.

2014-03-01

The chemiluminescence (CL) of water-soluble fluorescent carbon dots (C-dots) induced by direct chemical oxidation was investigated. C-dots were prepared by solvothermal method and characterized by fluorescence spectra and transmission electron microscopy. It was found that K3Fe(CN)6 could directly oxidize C-dots to produce a relatively intense CL emission. The mechanism of CL generation was investigated based on the fluorescence and CL emission spectra and the effect of radical scavengers on the CL intensity. The inhibitive effect of some metal ions and biologically important molecules on the CL intensity of the system was examined and the potential of the system for the determination of these species at trace levels was studied. In order to evaluate the capability of method to real sample analysis, it was applied to the determination of Cr(VI) and adrenaline in water and injection samples, respectively.

The Moon Phases in a Paper Box. (Spanish Title: Las Fases de la Luna en Una Caja de Cartón.) As Fases da Lua Numa Caixa de Papelão

NASA Astrophysics Data System (ADS)

de Fátima O. Saraiva, Maria; Amador, Cláudio B.; Kemper, Érico; Goulart, Paulo; Muller, Angela

2007-12-01

We present a very simple concrete model to demonstrate the concept of phases of an illuminated body. The main objective of our model is to help the understanding of the Moon phases as viewed from the perspective of an observer on Earth. The material allows the visualization of two important effects: (1st) even though all the time half Moon is illuminated by the Sun, we see different fractions of the illuminated Moon surface, depending on our angle of sight; (2nd) the orientation of the convex part of the Moon in the crescent and waning phases on the sky also depends on our perspective from Earth. The use of a closed box allows one to see the contrast among the different phases with no need of a dark room. We also present a text on the Moon phases, emphasizing the dependence of the aspect of the bright part on the angle of sight. En este trabajo proponemos la construcción de material didáctico de bajo costo para demostración del concepto de fases de un cuerpo iluminado. El principal objetivo de nuestro material es facilitar la comprensión de las fases de la Luna desde la perspectiva de un observador en la Tierra. El material ayuda la visualización de dos efectos importantes: (1º) a pesar de tener siempre la mitad de la Luna (representada por una bolita de espuma plástica o de ping-pong), iluminada por el Sol ( representado por una fuente de luz natural o artificial), vemos diferentes fracciones de su superficie iluminada, dependiendo del ángulo por el cual la vemos; (2º) la orientación del borde convexo de la Luna en las fases Creciente y Menguante también depende de la perspectiva por la cual la miramos desde la Tierra. El uso de una caja cerrada permite observar el contraste entre las diferentes fases sin necesidad de estar en un recinto oscuro. Presentamos también un texto explicativo sobre las fases de la Luna, enfatizando la dependencia de la apariencia de la parte iluminada con el ángulo de visión. Neste trabalho propomos a construção de material didático de baixo custo para demonstração do conceito de fases de um corpo iluminado. O principal objetivo de nosso material é facilitar a compreensão das fases da Lua da perspectiva de um observador na Terra. O material ajuda na visualização de dois efeitos importantes: (1º) mesmo tendo sempre a metade da "Lua" (representada por uma bolinha de isopor ou de ping-pong) iluminada pelo "Sol" (representado por uma fonte de luz natural ou artificial), nós vemos diferentes frações de sua superfície iluminada, dependendo do ângulo pelo qual a olhamos; (2º) a orientação da borda convexa da Lua nas fases Crescente e Minguante também depende da perspectiva pela qual a olhamos da Terra. O uso de uma caixa fechada permite observar o contraste entre as diferentes fases sem necessidade de estar em uma sala escurecida. Apresentamos também um texto explicativo sobre fases da Lua, enfatizando a dependência da aparência da parte iluminada com o ângulo de visada.

77 FR 23380 - Airworthiness Directives; Turbomeca S.A. Turboshaft Engines

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-19

... Airworthiness Directives; Turbomeca S.A. Turboshaft Engines AGENCY: Federal Aviation Administration (FAA), DOT....A. Arrius 2F turboshaft engines with P3 air pipe (first section) part number (P/N) 0 319 71 918 0... same inspections for installed engines, eliminates readjusting of the P3 air pipe (first section...

77 FR 42428 - Amendment of Jet Routes and VOR Federal Airways; Northeastern United States

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-19

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 71 Docket No. FAA-2012-0622; Airspace Docket No. 12-ANE-11 RIN 2120-AA66 Amendment of Jet Routes and VOR Federal Airways; Northeastern United States AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule; technical...

75 FR 27427 - Amendment of Jet Route J-120; Alaska

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-17

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 71 [Docket No. FAA-2009-0007; Airspace Docket No. 09-AAL-20] Amendment of Jet Route J-120; Alaska AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: This action amends Jet Route J-120, in Alaska. The FAA is...

75 FR 20774 - Modification of Jet Routes J-37 and J-55; Northeast United States

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-21

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 71 [Docket No. FAA-2010-0003; Airspace Docket No. 09-ANE-104] Modification of Jet Routes J-37 and J-55; Northeast United States AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: This action modifies Jet...

76 FR 42609 - Airworthiness Directives; Lycoming Engines Model TIO 540-A Series Reciprocating Engines

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-19

...-0691; Directorate Identifier 2011-NE-26-AD] RIN 2120-AA64 Airworthiness Directives; Lycoming Engines Model TIO 540-A Series Reciprocating Engines AGENCY: Federal Aviation Administration (FAA), DOT. ACTION... directive (AD) for Lycoming Engines model TIO 540-A series reciprocating engines. The existing AD, AD 71-13...

76 FR 28887 - Revocation of Class E Airspace; Ozark, MO

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-19

...-0432; Airspace Docket No. 11-ACE-8] Revocation of Class E Airspace; Ozark, MO AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: This action removes Class E airspace at Ozark, MO... Regulations (14 CFR) Part 71 by removing Class E airspace in the Ozark, MO, area. Abandonment of the former...

77 FR 5733 - Proposed Modification of Area Navigation (RNAV) Route Q-62; Northeast United States

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-06

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 71 Docket No. FAA-2011-1407; Airspace Docket No. 11-AGL-25 RIN 2120-AA66 Proposed Modification of Area Navigation (RNAV) Route Q-62; Northeast United States AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of...

Printer model for dot-on-dot halftone screens

NASA Astrophysics Data System (ADS)

Balasubramanian, Raja

1995-04-01

A printer model is described for dot-on-dot halftone screens. For a given input CMYK signal, the model predicts the resulting spectral reflectance of the printed patch. The model is derived in two steps. First, the C, M, Y, K dot growth functions are determined which relate the input digital value to the actual dot area coverages of the colorants. Next, the reflectance of a patch is predicted as a weighted combination of the reflectances of the four solid C, M, Y, K patches and their various overlays. This approach is analogous to the Neugebauer model, with the random mixing equations being replaced by dot-on-dot mixing equations. A Yule-Neilsen correction factor is incorporated to account for light scattering within the paper. The dot area functions and Yule-Neilsen parameter are chosen to optimize the fit to a set of training data. The model is also extended to a cellular framework, requiring additional measurements. The model is tested with a four color xerographic printer employing a line-on-line halftone screen. CIE L*a*b* errors are obtained between measurements and model predictions. The Yule-Neilsen factor significantly decreases the model error. Accuracy is also increased with the use of a cellular framework.

Paralinear Oxidation of CVD SiC in Simulated Fuel-Rich Combustion

NASA Technical Reports Server (NTRS)

Fox, Dennis S.; Opila, Elizabeth J.; Hann, Raiford E.

2000-01-01

The oxidation kinetics of CVD SiC were measured by thermogravimetric analysis (TGA) in a 4H2 (central dot) 12H2O (central dot) 10CO (central dot) 7CO2 (central dot) 67N2 gas mixture flowing at 0.44 cm/s at temperatures between 1300 and 1450 C in fused quartz furnace tubes at I atm total pressure. The SiC was oxidized to form solid SiO2. At less than or = 1350 C, the SiO2 was in turn volatilized. Volatilization kinetics were consistent with the thermodynamic predictions based on SiO formation. These two simultaneous reactions resulted in overall paralinear kinetics. A curve fitting technique was used to determine the linear and parabolic rate constants from the paralinear kinetic data. Volatilization of the protective SiO2 scale resulted in accelerated consumption of SiC. Recession rates under conditions more representative of actual combustors were estimated from the furnace data.

Heterogeneous assembled nanocomplexes for ratiometric detection of highly reactive oxygen species in vitro and in vivo.

PubMed

Ju, Enguo; Liu, Zhen; Du, Yingda; Tao, Yu; Ren, Jinsong; Qu, Xiaogang

2014-06-24

Probes for detecting highly reactive oxygen species (hROS) are critical to both understanding the etiology of the disease and optimizing therapeutic interventions. However, problems such as low stability due to autoxidation and photobleaching and unsuitability for biological application in vitro and in vivo, as well as the high cost and complex procedure in synthesis and modification, largely limit their application. In this work, binary heterogeneous nanocomplexes (termed as C-dots-AuNC) constructed from gold clusters and carbon dots were reported. The fabrication takes full advantages of the inherent active groups on the surface of the nanoparticles to avoid tedious modification and chemical synthetic processes. Additionally, the assembly endowed C-dots-AuNC with improved performance such as the fluorescence enhancement of AuNCs and stability of C-dots to hROS. Moreover, the dual-emission property allows sensitive imaging and monitoring of the hROS signaling in living cells with high contrast. Importantly, with high physiological stability and excellent biocompatibility, C-dots-AuNC allows for the detection of hROS in the model of local ear inflammation.

Ratiometric Phosphorescent Probe for Thallium in Serum, Water, and Soil Samples Based on Long-Lived, Spectrally Resolved, Mn-Doped ZnSe Quantum Dots and Carbon Dots.

PubMed

Lu, Xiaomei; Zhang, Jinyi; Xie, Ya-Ni; Zhang, Xinfeng; Jiang, Xiaoming; Hou, Xiandeng; Wu, Peng

2018-02-20

Thallium (Tl) is an extremely toxic heavy metal and exists in very low concentrations in the environment, but its sensing is largely underexplored as compared to its neighboring elements in the periodic table (especially mercury and lead). In this work, we developed a ratiometric phosphorescent nanoprobe for thallium detection based on Mn-doped ZnSe quantum dots (QDs) and water-soluble carbon dots (C-dots). Upon excitation with 360 nm, Mn-doped ZnSe QDs and C-dots can emit long-lived and spectrally resolved phosphorescence at 580 and 440 nm, respectively. In the presence of thallium, the phosphorescence emission from Mn-doped ZnSe QDs could be selectively quenched, while that from C-dots retained unchanged. Therefore, a ratiometric phosphorescent probe was thus developed, which can eliminate the potential influence from both background fluorescence and other analyte-independent external environment factors. Several other heavy metal ions caused interferences to thallium detection but could be efficiently masked with EDTA. The proposed method offered a detection limit of 1 μg/L, which is among the most sensitive probes ever reported. Successful application of this method for thallium detection in biological serum as well as in environmental water and soil samples was demonstrated.

Control of Photoluminescence of Carbon Nanodots via Surface Functionalization using Para-substituted Anilines

NASA Astrophysics Data System (ADS)

Kwon, Woosung; Do, Sungan; Kim, Ji-Hee; Seok Jeong, Mun; Rhee, Shi-Woo

2015-07-01

Carbon nanodots (C-dots) are a kind of fluorescent carbon nanomaterials, composed of polyaromatic carbon domains surrounded by amorphous carbon frames, and have attracted a great deal of attention because of their interesting properties. There are still, however, challenges ahead such as blue-biased photoluminescence, spectral broadness, undefined energy gaps and etc. In this report, we chemically modify the surface of C-dots with a series of para-substituted anilines to control their photoluminescence. Our surface functionalization endows our C-dots with new energy levels, exhibiting long-wavelength (up to 650 nm) photoluminescence of very narrow spectral widths. The roles of para-substituted anilines and their substituents in developing such energy levels are thoroughly studied by using transient absorption spectroscopy. We finally demonstrate light-emitting devices exploiting our C-dots as a phosphor, converting UV light to a variety of colors with internal quantum yields of ca. 20%.

Mechanofluorochromic Carbon Nanodots: Controllable Pressure-Triggered Blue- and Red-Shifted Photoluminescence.

PubMed

Liu, Cui; Xiao, Guanjun; Yang, Mengli; Zou, Bo; Zhang, Zhi-Ling; Pang, Dai-Wen

2018-02-12

Mechanofluorochromic materials, which change their photoluminescence (PL) colors in responding to mechanical stimuli, can be used as mechanosensors, security papers, and photoelectronic devices. However, traditional mechanofluorochromic materials can only be adjusted to a monotone direction upon the external stimuli. Controllable pressure-triggered blue- and red-shifted PL is reported for C-dots. The origin of mechanofluorochromism (MFC) in C-dots is interpreted based on structure-property relationships. The carbonyl group and the π-conjugated system play key roles in the PL change of C-dots under high pressure. As the pressure increases, the enhanced π-π stacking of the π-conjugated system causes the red-shift of PL, while the conversion of carbonyl groups eventually induces a blue-shift. Together with their low toxicity, good hydrophilicity, and small size, the tunable MFC property would boost various potential applications of C-dots. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

U.S. EPA, Pesticide Product Label, SBP-1382/ESOBIOTHRIN/P.B.O INSEC. AEROSOL 0.2% + 0.3% + 1.2% FORMULA, 10/14/1988

EPA Pesticide Factsheets

2011-04-14

... 11,.,1., PlllCAm .. uy "Innall lua_" •• 1 ••• _ •••• IIC 111111'" CAIn I III 0S • .,.. ... II..... T... ..I' ••• 1 .... _ ." , ,I •• ,.bl? a • .... 2 ..... __ ~ ... ...

Data-driven approach to human motion modeling with Lua and gesture description language

NASA Astrophysics Data System (ADS)

Hachaj, Tomasz; Koptyra, Katarzyna; Ogiela, Marek R.

2017-03-01

The aim of this paper is to present the novel proposition of the human motion modelling and recognition approach that enables real time MoCap signal evaluation. By motions (actions) recognition we mean classification. The role of this approach is to propose the syntactic description procedure that can be easily understood, learnt and used in various motion modelling and recognition tasks in all MoCap systems no matter if they are vision or wearable sensor based. To do so we have prepared extension of Gesture Description Language (GDL) methodology that enables movements description and real-time recognition so that it can use not only positional coordinates of body joints but virtually any type of discreetly measured output MoCap signals like accelerometer, magnetometer or gyroscope. We have also prepared and evaluated the cross-platform implementation of this approach using Lua scripting language and JAVA technology. This implementation is called Data Driven GDL (DD-GDL). In tested scenarios the average execution speed is above 100 frames per second which is an acquisition time of many popular MoCap solutions.

Avalanches and diffusion in bubble rafts

NASA Astrophysics Data System (ADS)

Maloney, C. E.

2015-07-01

Energy dissipation distributions and particle displacement statistics are studied in the mean-field version of Durian's bubble model. A two-dimensional (2D) bi-disperse mixture is simulated at various strain rates, \\dotγ , and packing ratios, ϕ, above the rigidity onset at φ=φc . Well above φc , and at sufficiently low \\dotγ , the system responds in a highly bursty way, reminiscent of other dynamically critical systems with a power-law distribution of energy dissipation. As one increases \\dotγ at fixed ϕ or tunes φ→ φc at fixed \\dotγ , the bursty behavior vanishes. Displacement distributions are non-Fickian at short times but cross to a Fickian regime at a universal strain, Δγ* , independent of \\dotγ and ϕ. Despite the profound differences in short-time dynamics, at intermediate Δγ the systems exhibit qualitatively similar spatial patterns of deformation with lines of slip extending across large fractions of the simulation cell. These deformation patterns explain the observed diffusion constants and the universal crossover time to Fickian behavior.

Single step hydrothermal synthesis of carbon nanodot decorated V2O5 nanobelts as hybrid conducting material for supercapacitor application

NASA Astrophysics Data System (ADS)

Narayanan, Remya

2017-09-01

Carbon nanodot (C-dot) decorated V2O5 (C-dot@V2O5) nanobelts are synthesized by single step, low cost hydrothermal route at low temperature by using V2O5 and glucose as precursors. We have not added any extra organic solvents or surfactants which are commonly used for the preparation of different nanostructures of V2O5. Electron microscopy analyses demonstrate that C-dot is entrapped inside V2O5 nanobelts which in turn enhance the conductivity and ion propagation property of this composite material. The C-dot@V2O5 nanobelts exhibit an excellent three electrode electrochemical performance in 1 M Na2SO4 and which showed a specific capacitance of 270 F g-1 at 1 A g-1, which is 4.5 times higher than the pristine V2O5 electrode. The electrochemical energy storage capacity of this hybrid is investigated towards solid state supercapacitor application also for the first time by employing electrophoretically deposited C-dot as the counter electrode and Li based gel as the electrolyte. The hybrid material delivers an energy density of 60 W h kg-1 and a reasonably high power density of 4.1 kW kg-1 at 5 A g-1 and good cycling stability and capacitance retention of about 87% was observed even after 5000 cycles. Above mentioned results clearly show that C-dot embedded hybrid, nanostructured transition metal oxides has great potential towards fabrication of electrodes for energy storage devices.

Connecting the Dots: How U.S. Global Health Programs Can Improve International Health Regulation Compliance

DTIC Science & Technology

2014-12-01

50 E. ACTIVITIES , FUNDING, AND ANALYSIS .............................................51 1. Global Emerging Infectious Disease System...Organizational Chart ..............................................................................71 Figure 9. CDC: Global Health Activities Map...of the WHO was roughly $2.2 billion the same year.12 New threats like antibacterial -resistant infections have resulted in at least 23,000 deaths with

75 FR 33164 - Modification of Jet Routes J-32, J-38, and J-538; Minnesota

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-11

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 71 [Docket No. FAA-2009-1080; Airspace Docket No. 09-AGL-13] RIN 2120-AA66 Modification of Jet Routes J-32, J-38, and J-538; Minnesota AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: This action...

75 FR 12674 - Amendment of Jet Routes and VOR Federal Airways in the Vicinity of Gage, OK

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-17

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 71 [Docket No. FAA-2010-0004; Airspace Docket No. 09-ASW-32] RIN 2120-AA66 Amendment of Jet Routes and VOR Federal Airways in the Vicinity of Gage, OK AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule...

75 FR 5704 - Proposed Modification of Jet Routes J-37 and J-55; Northeast United States

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-04

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 71 [Docket No. FAA-2010-0003; Airspace Docket No. 09-ANE-104] RIN 2120-AA66 Proposed Modification of Jet Routes J-37 and J-55; Northeast United States AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of proposed...

Native structure of a type IV secretion system core complex essential for Legionella pathogenesis.

PubMed

Kubori, Tomoko; Koike, Masafumi; Bui, Xuan Thanh; Higaki, Saori; Aizawa, Shin-Ichi; Nagai, Hiroki

2014-08-12

Bacterial type IV secretion systems are evolutionarily related to conjugation systems and play a pivotal role in infection by delivering numerous virulence factors into host cells. Using transmission electron microscopy, we report the native molecular structure of the core complex of the Dot/Icm type IV secretion system encoded by Legionella pneumophila, an intracellular human pathogen. The biochemically isolated core complex, composed of at least five proteins--DotC, DotD, DotF, DotG, and DotH--has a ring-shaped structure. Intriguingly, morphologically distinct premature complexes are formed in the absence of DotG or DotF. Our data suggest that DotG forms a central channel spanning inner and outer membranes. DotF, a component dispensable for type IV secretion, plays a role in efficient embedment of DotG into the functional core complex. These results highlight a common scheme for the biogenesis of transport machinery.

Carnobacterium pleistocenium sp. nov., a novel psychrotolerant, facultative anaerobe isolated from permafrost of the Fox Tunnel in Alaska

NASA Technical Reports Server (NTRS)

Pilkuta, Elena V.; Marsic, Damien; Bej, Asim; Tang, Jane; Krader, Paul; Hoover, Richard B.

2005-01-01

A novel, psychrotolerant, facultative anaerobe, strain FTRl, was isolated from Pleistocene ice from the permafrost tunnel in Fox, Alaska. Gram-positive, motile, rod-shaped cells were observed with sizes 0(raised dot)6-0(raised dot)7 x 0(raised dot)9-1(raised dot)5 microns. Growth occurred within the pH range 6(raised dot)5-9(raised dot)5 with optimum growth at pH 7(raised dot)3-7(raised dot)5. The temperature range for growth of the novel isolate was 0-28 C and optimum growth occurred at 24 C. The novel isolate does not require NaCl; growth was observed between 0 and 5% NaCl with optimum growth at 0(raised dot)5% (w/v). The novel isolate was a catalase-negative chemoorganoheterotroph that used as substrates sugars and some products of proteolysis. The metabolic end products were acetate, ethanol and CO2. Strain FTRl was sensitive to ampicillin, tetracycline, chloramphenicol, rifampicin, kanamycin and gentamicin. 16s rRNA gene sequence analysis showed 99(raised dot)8% similarity between strain FTR1 and Carnobacterium alterfunditum, but DNA-DNA hybridization between them demonstrated 39 plus or minus 1(raised dot)5% relatedness. On the basis of genotypic and phenotypic characteristics, it is proposed that strain FTRl (= ATCC BAA-754T= JCM 12174T=CIP 108033) be assigned to the novel species Carnobacterium pleistocenium sp. nov.

Thermal performance characterization of residential wall systems using a calibrated hot box with airflow induced by differential pressures

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

Jones, D.C.; Ober, D.G.; Goodrow, J.T.

1995-09-01

ASTM E 283 ad ASTM E 1424 in conjunction with ASTM C 976 were used to study the effect of airflow on thermal performance of the wall. A typical residential 2 {times} 4 stud wall was constructed and placed on top of a subfloor, making a 2.44 {times} 2.74 m (8 by 9 ft) test specimen. This base wall assembly was then covered with two types of XPS sheathing, various housewraps, a 15{number_sign} felt, and a polyethylene vapor retarder film in 40 different configurations and tested individually per ASTM E 283 and per ASTM C 976. For 24 of themore » 40 C 976 tests, a differential pressure was induced across the test wall as per and ASTM E 1424. Airflows ranged from undetectable airflow at 0 {center_dot} Pa {Delta}P to 1.63 L/s {center_dot} m{sup 2} for the base wall assembly alone. Difference in airflow resistance performance between the ASTM E 283 and ASTM E 1424 test methods were noted. Thermal testing results incorporating both ASTM C 976 and ASTM E 1424 for tests 1--28 produced apparent thermal conductances (C-values) in the range of 0.40 W/m{sup 2} {center_dot} K for a nondetectable airflow level to 1.81 W/m{sup 2} {center_dot} K for an airflow of 1.53 L/s {center_dot} m{sup 2} for the base wall assembly alone with a 20-Pa {Delta}P. The calculated C-value for this base wall assembly was 0.40 W/m{sup 2} {center_dot} K. Test results reveal that airflow rates as low as 0.2 L/s {center_dot} m{sup 2} could produce a 46% increase in apparent C-value. Similar thermal performance differences were revealed when thicker shiplap XPS sheathing was used. Tests were also conducted using an Air-Tight Drywall configuration showing the effect of wind washing on thermal performance. By sealing the gypsum drywall on the base wall assembly tested, the apparent C-value, when exposed to a 12.5 Pa wind pressure, was found to be equivalent to a base wall assembly configuration which allows 0.15 L/s {center_dot} m{sup 2} airflow to penetrate completely through.« less

Scanning gate imaging of two coupled quantum dots in single-walled carbon nanotubes.

PubMed

Zhou, Xin; Hedberg, James; Miyahara, Yoichi; Grutter, Peter; Ishibashi, Koji

2014-12-12

Two coupled single wall carbon nanotube quantum dots in a multiple quantum dot system were characterized by using a low temperature scanning gate microscopy (SGM) technique, at a temperature of 170 mK. The locations of single wall carbon nanotube quantum dots were identified by taking the conductance images of a single wall carbon nanotube contacted by two metallic electrodes. The single electron transport through single wall carbon nanotube multiple quantum dots has been observed by varying either the position or voltage bias of a conductive atomic force microscopy tip. Clear hexagonal patterns were observed in the region of the conductance images where only two sets of overlapping conductance rings are visible. The values of coupling capacitance over the total capacitance of the two dots, C(m)/C(1(2)) have been extracted to be 0.21 ∼ 0.27 and 0.23 ∼ 0.28, respectively. In addition, the interdot coupling (conductance peak splitting) has also been confirmed in both conductance image measurement and current-voltage curves. The results show that a SGM technique enables spectroscopic investigation of coupled quantum dots even in the presence of unexpected multiple quantum dots.

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

Javahery, G.; Petrie, S.; Wang, J.

Results are reported for the reactions of the fullerene ions C[sub 60[center dot]+], C[sub 70[center dot]+], C[sub 60][sup 2+], C[sub 70][sup 2+], and C[sub 60[center dot]3+] with the nitriles HCN, CH[sub 3]CN, CH[sub 2]CHCN, CH[sub 3]CH[sub 2]CN, CH[sub 2]CHCH[sub 2]CN, CH[sub 3]CH[sub 2]CH[sub 2]CN, (CH[sub 3])[sub 2]CHCN, C[sub 2]N[sub 2], and CH[sub 2](CN)[sub 2]. The reactions were studied using a selected-ion flow tube (SIFT) at 294 [+-] 2 K and a helium buffer gas pressure of 0.35 [+-] 0.01 Torr and exhibited a wide range of chemical behavior. For the monocations C[sub 60][sup [center dot]+] and C[sub 70][sup [center dot]+],more » no detectable reaction occurred with any of the nitriles. For the dications C[sub 60][sup 2+], and C[sub 70][sup 2+], the only primary or secondary product channel evident in all instances was addition: tertiary association was seen to be considerably less efficient than the primary and secondary reactions, and the formation of a quadruple adduct C[sub 60](RCN)[sub 4][sup 2+] was only detected in the reaction with butyronitrile, CH[sub 3]CH[sub 2]CH[sub 2]CN. The observed primary rate coefficients show a very clear dependence upon the molecular complexity of the nitrile: association proceeds more efficiently for nitriles with a higher number of hydrogen atoms. This observation is explained in terms of a model which relates the number of C-H bonds - or, alternatively, the number of internal rotational modes - in the collision complex to the lifetime and probability of stabilization of this complex. 42 refs., 5 figs., 3 tabs.« less

Behavioral and neural stability of attention bias to threat in healthy adolescents

PubMed Central

Britton, Jennifer C.; Sequeira, Stefanie; Ronkin, Emily G.; Chen, Gang; Bar-Haim, Yair; Shechner, Tomer; Ernst, Monique; Fox, Nathan A.; Leibenluft, Ellen; Pine, Daniel S.

2016-01-01

Considerable translational research on anxiety examines attention bias to threat and the efficacy of attention training in reducing symptoms. Imaging research on the stability of brain functions engaged by attention bias tasks could inform such research. Perturbed fronto-amygdala function consistently arises in attention bias research on adolescent anxiety. The current report examines the stability of the activation and functional connectivity of these regions on the dot-probe task. Functional magnetic resonance imaging (fMRI) activation and connectivity data were acquired with the dot-probe task in 39 healthy youth (f =18, Mean Age = 13.71 years, SD = 2.31) at two time points, separated by approximately nine weeks. Intraclass-correlations demonstrate good reliability in both neural activation for the ventrolateral PFC and task-specific connectivity for fronto-amygdala circuitry. Behavioral measures showed generally poor test-retest reliability. These findings suggest potential avenues for future brain imaging work by highlighting brain circuitry manifesting stable functioning on the dot-probe attention bias task. PMID:27129757

STS-52 CANEX-2 Canadian Target Assembly (CTA) held by RMS over OV-102's PLB

NASA Image and Video Library

1992-11-01

STS052-71-057 (22 Oct-1 Nov 1992) --- This 70mm frame, photographed with a handheld Hasselblad camera aimed through Columbia's aft flight deck windows, captures the operation of the Space Vision System (SVS) experiment above the cargo bay. Target dots have been placed on the Canadian Target Assembly (CTA), a small satellite, in the grasp of the Canadian-built remote manipulator system (RMS) arm. SVS utilized a Shuttle TV camera to monitor the dots strategically arranged on the satellite, to be tracked. As the satellite moved via the arm, the SVS computer measured the changing position of the dots and provided real-time television display of the location and orientation of the CTA. This type of displayed information is expected to help an operator guide the RMS or the Mobile Servicing System (MSS) of the future when berthing or deploying satellites. Also visible in the frame is the U.S. Microgravity Payload (USMP-01).

Red Dot Basal Cell Carcinoma: Report of Cases and Review of This Unique Presentation of Basal Cell Carcinoma.

PubMed

Cohen, Philip R

2017-03-22

Red dot basal cell carcinoma is a unique variant of basal cell carcinoma. Including the three patients described in this report, red dot basal cell carcinoma has only been described in seven individuals. This paper describes the features of two males and one female with red dot basal cell carcinoma and reviews the characteristics of other patients with this clinical subtype of basal cell carcinoma. A 70-year-old male developed a pearly-colored papule with a red dot in the center on his nasal tip. A 71-year-old male developed a red dot surrounded by a flesh-colored papule on his left nostril. Lastly, a 74-year-old female developed a red dot within an area of erythema on her left mid back. Biopsy of the lesions all showed nodular and/or superficial basal cell carcinoma. Correlation of the clinical presentation and pathology established the diagnosis of red dot basal cell carcinoma. The tumors were treated by excision using the Mohs surgical technique. Pubmed was searched with the keyword: basal, cell, cancer, carcinoma, dot, red, and skin. The papers generated by the search and their references were reviewed. Red dot basal cell carcinoma has been described in three females and two males; the gender was not reported in two patients. The tumor was located on the nose (five patients), back (one patient) and thigh (one patient). Cancer presented as a solitary small red macule or papule; often, the carcinoma was surrounded by erythema or a flesh-colored papule. Although basal cell carcinomas usually do not blanch after a glass microscope slide is pressed against them, the red dot basal cell carcinoma blanched after diascopy in two of the patients, resulting in a delay of diagnosis in one of these individuals. Dermoscopy may be a useful non-invasive modality for evaluating skin lesions when the diagnosis of red dot basal cell carcinoma is considered. Mohs surgery is the treatment of choice; in some of the patients, the ratio of the area of the postoperative wound to that of the preoperative cancer was greater than 12:1, demonstrating a significant lateral spread of the tumor beyond the observed clinical margins of the neoplasm. In conclusion, in a patient with a personal history of actinic keratosis or nonmelanoma skin cancer, the appearance of a new red dot in a sun-exposed site should prompt additional evaluation of the skin lesion to exclude or establish the diagnosis of red dot basal cell carcinoma.

Red Dot Basal Cell Carcinoma: Report of Cases and Review of This Unique Presentation of Basal Cell Carcinoma

PubMed Central

2017-01-01

Red dot basal cell carcinoma is a unique variant of basal cell carcinoma. Including the three patients described in this report, red dot basal cell carcinoma has only been described in seven individuals. This paper describes the features of two males and one female with red dot basal cell carcinoma and reviews the characteristics of other patients with this clinical subtype of basal cell carcinoma. A 70-year-old male developed a pearly-colored papule with a red dot in the center on his nasal tip. A 71-year-old male developed a red dot surrounded by a flesh-colored papule on his left nostril. Lastly, a 74-year-old female developed a red dot within an area of erythema on her left mid back. Biopsy of the lesions all showed nodular and/or superficial basal cell carcinoma. Correlation of the clinical presentation and pathology established the diagnosis of red dot basal cell carcinoma. The tumors were treated by excision using the Mohs surgical technique. Pubmed was searched with the keyword: basal, cell, cancer, carcinoma, dot, red, and skin. The papers generated by the search and their references were reviewed. Red dot basal cell carcinoma has been described in three females and two males; the gender was not reported in two patients. The tumor was located on the nose (five patients), back (one patient) and thigh (one patient). Cancer presented as a solitary small red macule or papule; often, the carcinoma was surrounded by erythema or a flesh-colored papule. Although basal cell carcinomas usually do not blanch after a glass microscope slide is pressed against them, the red dot basal cell carcinoma blanched after diascopy in two of the patients, resulting in a delay of diagnosis in one of these individuals. Dermoscopy may be a useful non-invasive modality for evaluating skin lesions when the diagnosis of red dot basal cell carcinoma is considered. Mohs surgery is the treatment of choice; in some of the patients, the ratio of the area of the postoperative wound to that of the preoperative cancer was greater than 12:1, demonstrating a significant lateral spread of the tumor beyond the observed clinical margins of the neoplasm. In conclusion, in a patient with a personal history of actinic keratosis or nonmelanoma skin cancer, the appearance of a new red dot in a sun-exposed site should prompt additional evaluation of the skin lesion to exclude or establish the diagnosis of red dot basal cell carcinoma. PMID:28465868

Study of binary and ternary organic hybrid CdSe quantum dot photodetector

NASA Astrophysics Data System (ADS)

Ramar, M.; Kajal, S.; Pal, Prabir; Srivastava, R.; Suman, C. K.

2015-09-01

The hybrid binary and ternary photodetectors (PDs) were fabricated from P3HT-PC71BM with CdSe quantum dot (QD) materials. The absorption spectra of P3HT:PC71BM (named as B1), P3HT:CdSe (B2) and P3HT:CdSe:PC71BM (T) active blended material were analyzed in the wavelength range from 350 to 800 nm. The current density-voltage characteristics of the device were measured in dark and under illumination for study of detector detectivities and the contact with electrode. The ratio at -0.5 V for PDs B1, B2 and T is 1.1 × 102, 1.9 × 102 and 1.8 × 103, respectively. The values of detectivity for B1, B2 and T are 1 × 1010, 2 × 1010 and 7 × 1011 Jones, respectively. The for PD T is ten times in comparison with B1 and B2 PDs. The linear dynamic range (LDR) value for ternary device is more than double to both binary PDs. The absorption by CdSe QD increases the photon efficiency in the ternary detector, and at the same time the ternary detectors have high detectivity in broad spectral range. The responsivity of current to the light intensity exponent θ for detector B1, B2 and T is ~0.55, 0.55 and 0.62, respectively, which represents a complex process of electron hole generation, recombination and trapping within active material.

Controlling Quantum-dot Light Absorption and Emission by a Surface-plasmon Field

DTIC Science & Technology

2014-11-03

as well as photon conversion by a surface-plasmon- polariton near field is explored for a quantum dot located above a metal surface. In contrast to the...2009). 7. D. Dini, R. Köhler, A. Tredicucci, G. Biasiol, and L. Sorba, “Microcavity polariton splitting of intersubband transitions,” Phys. Rev. Lett...S. De Liberato, C. Ciuti, P. Klang, G. Strasser, and C. Sirtori, “Ultrastrong light-matter coupling regime with polariton dots,” Phys. Rev. Lett. 105

Functionalization of Semiconductor Nanomaterials for Optoelectronic Devices And Components

DTIC Science & Technology

2015-03-04

conversion efficiency of InAs quantum dot solar cell by using a single layer anatase TiO2 anti-reflection coating,” R. Vasan, Y. F. Makableh, J. C...dx.doi.org/10.1557//opl.2013.742 9. “The Optimization of InP/ZnS Core/Shell Nanocrystals and TiO2 Nanotubes for Quantum Dot Sensitized Solar Cells ...Quantum Dots Solar Cells Performance,” J. C. Sarker, Y. F. Makableh, R. Vasan, S. Lee, M. O. Manasreh, and M. Benamara, IEEE J. Photovoltaic. (submitted

[Shortages in Swedish tuberculosis care. Good results only in 71 percent of cases after 12-month treatment as shown in a current study].

PubMed

Romanus, V; Julander, I; Blom-Bülow, B; Larsson, L O; Normann, B; Boman, G

2000-11-29

During the period August 1994-December 1995 783 cases of active tuberculos (TB) were notified to the health authorities in Sweden. By means of questionnaires sent to the consulting physicians (92 per cent response rate) the treatment outcome was studied twelve months after the diagnosis. Out of 676 patients only 71 per cent were reported to have completed the treatment and be cured of TB. This indicates that there is room for improvement as regards monitoring patients, if necessary by Directly Observed Therapy (DOT), in order to make sure that prescribed treatment is adhered to.

In sílico identification and characterization of putative Dot/Icm secreted virulence effectors in the fish pathogen Piscirickettsia salmonis.

PubMed

Labra, Álvaro; Arredondo-Zelada, Oscar; Flores-Herrera, Patricio; Marshall, Sergio H; Gómez, Fernando A

2016-03-01

Piscirickettsia salmonis seriously affects the Chilean salmon industry. The bacterium is phylogenetically related to Legionella pneumophila and Coxiella burnetii, sharing a Dot/Icm secretion system with them. Although it is well documented that L. pneumophila and C. burnetii secrete different virulence effectors via this Dot/Icm system in order to attenuate host cell responses, to date there have been no reported virulence effectors secreted by the Dot/Icm system of P. salmonis. Using several annotations of P. salmonis genome, here we report an in silico analyses of 4 putative Dot/Icm effectors. Three of them contain ankyrin repeat domains and the typical conserved 3D structures of this protein family. The fourth one is highly similar to one of the Dot/Icm-dependent effectors of L. pneumophila. Additionally, all the potential P. salmonis effectors contain a classical Dot/Icm secretion signal in their C-terminus, consisting of: an E-Block, a hydrophobic residue in -3 or -4 and an electronegative charge. Finally, qPCR analysis demonstrated that these proteins are overexpressed early in infection, perhaps contributing to the generation of a replicative vacuole, a key step in the neutralizing strategy proposed for the Dot/Icm system. In summary, this report identifies four Dot/Icm-dependent effectors in P. salmonis. Copyright © 2015 Elsevier Ltd. All rights reserved.

Bacteriologic monitoring of multidrug-resistant tuberculosis patients in five DOTS-Plus pilot projects.

PubMed

Gammino, V M; Taylor, A B; Rich, M L; Bayona, J; Becerra, M C; Bonilla, C; Gelmanova, I; Hollo, V; Jaramillo, E; Keshavjee, S; Leimane, V; Mitnick, C D; Quelapio, M I D; Riektsina, V; Tupasi, T E; Wells, C D; Zignol, M; Cegielski, P J

2011-10-01

Multidrug-resistant tuberculosis programs in DOTS-Plus pilot sites in five countries. To calculate sputum conversion time and its relationship to treatment outcome, document the frequency of culture reversions and examine concordance of smear and culture to assess the potential consequences of monitoring by smear microscopy alone. Retrospective cohort analysis of 1926 patients receiving individualized, second-line therapy. Among 1385 sputum culture-positive cases at baseline, 1146 (83%) experienced at least one culture conversion during treatment. Conversion, however, was not sustained in all patients: 201 (15%) experienced initial culture conversion and at least one subsequent culture reversion to positive; 1064 (77%) achieved sustained culture conversion. Median time to culture conversion was 3 months. Among 206 patients whose nal conversion occurred 7-18 months after the initiation of therapy, 71% were cured or had completed treatment. Prolonged treatment for patients with delayed conversion may be beneficial, as 71% of late converters still achieved cure or completed treatment. This has implications for programs with de ned end points for treatment failure. The interval between rst and nal conversion among patients whose initial con- version is not sustained raises concern with respect to the ongoing debate regarding duration of treatment and the definition of cure.

A Facile Photoluminescent Probe for Picric Acid Detection Using Carbon Nanodots Prepared by Sichuan Bergamot.

PubMed

Deng, Xiang; Huang, Xiaomei

2018-03-01

A facile photoluminescent probe for picric acid (PA) detection was developed using photoluminescent carbon nanodots (C-dots), which was obtained from a traditional Chinese medicinal material Sichuan Bergamot via a one-step hydrothermal method for the first time. The as-prepared photoluminescent C-dots show favorable blue color photoluminescence with the maximum emission at 440 nm. It has been successfully applied as a photoluminescent probe for the detection of PA. This photoluminescent probe exhibits excellent sensitivity and selectivity toward PA from 0.4 μM to 80 μM with correlation coefficient (r) of 0.9987. The limit of detection (LOD) for PA is 82 nM. Furthermore, the proposed C-dots for photoluminescent probe detection of PA in real water samples (river water, refinery wastewater and pharmaceutical factory wastewater) by adding 5 μM and 20 μM PA with satisfactory recoveries from 99.5% to 101.5%. These novel photoluminescent C-dots is promising in environmental analysis of PA.

Local Gate Control of a Carbon Nanotube Double Quantum Dot

DTIC Science & Technology

2016-04-04

Nanotube Double Quantum Dot N. Mason,*† M. J. Biercuk,* C. M. Marcus† We have measured carbon nanotube quantum dots with multiple electro- static gates and...computation. Carbon nanotubes have been considered lead- ing candidates for nanoscale electronic applica- tions (1, 2). Previous measurements of nano- tube...electronics have shown electron confine- ment (quantum dot) effects such as single- electron charging and energy-level quantization (3–5). Nanotube

MASH TL-4 evaluation of the TxDOT type C2P bridge rail.

DOT National Transportation Integrated Search

2017-02-01

The objective of this research was to evaluate the impact performance of the Texas Department of Transportation (TxDOT) Type C2P Bridge Rail according to the safety-performance evaluation guidelines included in the American Association of State Highw...

SU-F-T-323: A Post-Mastectomy Radiation Therapy Dose Distribution Study Using Nanodots and Films

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

Qian, X; Vaidya, K; Puckett, L

Purpose: In post-mastectomy radiation therapy (RT), skin dose must be accurately estimated to assess skin reactions such as erythema, desquamation and necrosis. Planning systems cannot always provide accurate dosimetry for target volumes distal to skin. Therefore, in-vivo dosimetry is necessary. A female anthropomorphic phantom was used with optically stimulated luminescence dosimeters (nanoDots) to measure dose to chest wall skin. In addition, EBT2 films was employed to measure dose to left lung and heart in post-mastectomy RT. Methods: Films and nanoDots were calibrated under full buildup conditions at 100cm SAD for 6MV photons. Five pieces of films were placed between slabsmore » of Rando phantom to assess dose to left lung and heart. Two layers of 0.5cm thick bolus were used to cover the whole left chest. Six pairs of nanoDots were placed at medical and lateral aspects on the bolus surface, between the 0.5cm bolus layers, and under the bolus. Three control nanoDots were placed on chest wall to quantify imaging dose. The phantom was CT scanned with all dosimeters in place, and treatment planning was performed with tangential fields (200cGy). All dosimeters were contoured on CT and dose was extracted. NanoDots were read using nanoDot reader and films were scanned using film scanner. The measured and calculated doses were tabulated. Results: Dose to 12 nanoDots were evaluated. Dose variance for surface nanoDots were +3.8%, +2.7%, −5% and −9.8%. Those at lateral positions, with greater beam obliquity had larger variance than the medial positions. A similar trend was observed for other nanoDots (Table1). Point doses from films for heart and the left lung were 112.7cGy and 108.7cGy, with +10.2% and +9.04% deviation from calculated values, respectively. Conclusion: Dosimetry provided by the advanced planning system was verified using NanoDots and films. Both nanoDots and films provided good estimation of dose distribution in post-mastectomy RT.« less

NMR structural studies of the ionizing radiation adduct 7-hydro-8-oxodeoxyguanosine (8-oxo-7H-dG) opposite deoxyadenosine in a DNA duplex. 8-oxo-7H-dG(syn)ter dot dA(anti) alignment at lesion site

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

Kouchakdjian, M.; Patel, D.J.; Bodepudi, V.

1991-02-05

Proton NMR studies are reported on the complementary d(C1-C2-A3-C4-T5-A6-oxo-G7-T8-C9-A10-C11-C12){center dot}d(G13-G14-T15-G16-A17-A18-T19-A20-G21-T22-G23-G24) dodecanucleotide duplex (designated 8-oxo-7H-dG{center dot}dA 12-mer), which contains a centrally located 7-hydro-8-oxodeoxyguanosine (8-oxo-7H-dG) residue, a group commonly found in DNA that has been exposed to ionizing radiation or oxidizing free radicals. From the NMR spectra it can be deduced that this moiety exists as two tautomers, or gives rise to two DNA conformations, that are in equilibrium and that exchange slowly. The present study focuses on the major component of the equilibrium that originates in the 6,8-dioxo tautomer of 8-oxo-7H-dG. The authors have assigned the exchangeable NH1, NH7, and NH{submore » 2}-2 base protons located on the Watson-Crick and Hoogsteen edges of 8-oxo-7H-dG7 in the 8-oxo-7H-dG{center dot}dA 12-mer duplex, using an analysis of one- and two-dimensional nuclear Overhauser enhancement (NOE) data in H{sub 2}O solution. They were able to detect a set of intra- and interstrand NOEs between protons (exchangeable and nonexchangeable) on adjacent residues in the d(A6-oxo-G7-T8){center dot}d(A17-A18-T19) trinucleotide segment centered about the lesion site that establishes stacking of the oxo-dG7(syn){center dot}dA(anti) pair between stable Watson-Crick dA6{center dot}dT19 and dT8{center dot}A17 base pairs with minimal perturbation of the helix. The structural studies demonstrate that 8-oxo-7H-dG(syn){center dot}dA(anti) forms a stable pair in the interior of the helix, providing a basis for the observed incorporation of dA opposite 8-oxo-7H-dG when readthrough occurs past this oxidized nucleoside base.« less

Implication of Proteins Containing Tetratricopeptide Repeats in Conditional Virulence Phenotypes of Legionella pneumophila

PubMed Central

Bandyopadhyay, Purnima; Sumer, Eren U.; Jayakumar, Deepak; Liu, Shuqing; Xiao, Huifang

2012-01-01

Legionella pneumophila, the causative agent of Legionnaires' disease, is a ubiquitous freshwater bacterium whose virulence phenotypes require a type IV secretion system (T4SS). L. pneumophila strain JR32 contains two virulence-associated T4SSs, the Dot/Icm and Lvh T4SSs. Defective entry and phagosome acidification phenotypes of dot/icm mutants are conditional and reversed by incubating broth-grown stationary-phase cultures in water (WS treatment) prior to infection, as a mimic of the aquatic environment of Legionella. Reversal of dot/icm virulence defects requires the Lvh T4SS and is associated with a >10-fold induction of LpnE, a tetratricopeptide repeat (TPR)-containing protein. In the current study, we demonstrated that defective entry and phagosome acidification phenotypes of mutants with changes in LpnE and EnhC, another TPR-containing protein, were similarly reversed by WS treatment. In contrast to dot/icm mutants for which the Lvh T4SS was required, reversal for the ΔlpnE or the ΔenhC mutant required that the other TPR-containing protein be present. The single and double ΔlpnE and ΔenhC mutants showed a hypersensitivity to sodium ion, a phenotype associated with dysfunction of the Dot/Icm T4SS. The ΔlpnE single and the ΔlpnE ΔenhC double mutant showed 3- to 9-fold increases in translocation of Dot/Icm T4SS substrates, LegS2/SplY and LepB. Taken together, these data identify TPR-containing proteins in a second mechanism by which the WS mimic of a Legionella environmental niche can reverse virulence defects of broth-grown cultures and implicate LpnE and EnhC directly or indirectly in translocation of Dot/Icm T4SS protein substrates. PMID:22563053

Preparation, structure, and luminescence of dinuclear lanthanide complexes of a novel imine-amine phenolate macrocycle

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

Matthews, K.D.; Kahwa, I.A.; Williams, D.J.

1994-03-30

Metal-free condensation of 2,6-diformyl-p-cresol with 3,6-dioxa-1,8-octanediamine followed by reduction with sodium tetrahydroborate and addition of lanthanide(III) nitrate salts, in that order, yield (slowly) crystalline dinuclear complexes of a novel imine-amine phenolate macrocycle 2. The decacoordination geometry of the identical Pr[sup 3+] ions in a C[sub 2v] 4A,6B-extended dodecahedron made up of two bidentate NO[sub 3]-ions, two phenolate and two either oxygens, and one imine and one amine nitrogens. Dinuclear lanthanide complexes of 2 appear to be more stable than those of the totally reduced chelate 2 in alcoholic media. The Tb[sub 2]2(NO[sub 3])[sub 4][center dot]1.2CH[sub 3]-OH and (La[sub 0.97]Tb[sub 0.03])[submore » 2]2(NO[sub 3])[sub 4][center dot]1.2CH[sub 3]OH compounds exhibit strong Tb[sup 3+] ([sup 5]D[sub 4] [yields] [sup 7]F[sub J]) emission sensitized by the single state of 2 at both 77 and 295 K. No Tb[sup 3+]-Tb[sup 3+] self-quenching or N-H trapping effects are observed at 77 K (decay rate is 598 s[sup [minus]1]); the coordination cavities of 2 are therefore potentially good hosts for Tb[sup 3+] in luminescent diagnostic agents. At room temperature the complex decay kinetics of Tb[sup 3+] in Tb[sub 2]2(NO[sub 3])[sub 4][center dot]1.2CH[sub 3]OH are similar to those of Tb[sub 2]1(NO[sub 3])[sub 4][center dot]H[sub 2]O. But for the dilute complex, (La[sub 0.97]-Tb[sub 0.03])[sub 2]2(NO[sub 3])[sub 4][center dot]1.35CH[sub 3]OH, unusual thermal equilibration of the ligand triplet and Tb[sup 3+] [sup 5]D[sub 4] states occurs at room temperature; the ligand-to-Tb[sup 3+] energy-transfer rate is [approx]4.36 x 10[sup 4] s[sup [minus]1], while Tb[sup 3+]-to-ligand back-energy-transfer is [approx]7.1 x 10[sup 4] s[sup [minus]1].« less

Self-assembled InN quantum dots on side facets of GaN nanowires

NASA Astrophysics Data System (ADS)

Bi, Zhaoxia; Ek, Martin; Stankevic, Tomas; Colvin, Jovana; Hjort, Martin; Lindgren, David; Lenrick, Filip; Johansson, Jonas; Wallenberg, L. Reine; Timm, Rainer; Feidenhans'l, Robert; Mikkelsen, Anders; Borgström, Magnus T.; Gustafsson, Anders; Ohlsson, B. Jonas; Monemar, Bo; Samuelson, Lars

2018-04-01

Self-assembled, atomic diffusion controlled growth of InN quantum dots was realized on the side facets of dislocation-free and c-oriented GaN nanowires having a hexagonal cross-section. The nanowires were synthesized by selective area metal organic vapor phase epitaxy. A 3 Å thick InN wetting layer was observed after growth, on top of which the InN quantum dots formed, indicating self-assembly in the Stranski-Krastanow growth mode. We found that the InN quantum dots can be tuned to nucleate either preferentially at the edges between GaN nanowire side facets, or directly on the side facets by tuning the adatom migration by controlling the precursor supersaturation and growth temperature. Structural characterization by transmission electron microscopy and reciprocal space mapping show that the InN quantum dots are close to be fully relaxed (residual strain below 1%) and that the c-planes of the InN quantum dots are tilted with respect to the GaN core. The strain relaxes mainly by the formation of misfit dislocations, observed with a periodicity of 3.2 nm at the InN and GaN hetero-interface. The misfit dislocations introduce I1 type stacking faults (…ABABCBC…) in the InN quantum dots. Photoluminescence investigations of the InN quantum dots show that the emissions shift to higher energy with reduced quantum dot size, which we attribute to increased quantum confinement.

49 CFR Appendix C to Part 180 - Eddy Current Examination With Visual Inspection for DOT 3AL Cylinders Manufactured of Aluminum...

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Eddy Current Examination With Visual Inspection... PACKAGINGS Pt. 180, App. C Appendix C to Part 180—Eddy Current Examination With Visual Inspection for DOT 3AL... procedure applicable to the test equipment it uses to perform eddy current examinations. 2. Visual...

Intracellular distribution of nontargeted quantum dots after natural uptake and microinjection

PubMed Central

Damalakiene, Leona; Karabanovas, Vitalijus; Bagdonas, Saulius; Valius, Mindaugas; Rotomskis, Ricardas

2013-01-01

Background: The purpose of this study was to elucidate the mechanism of natural uptake of nonfunctionalized quantum dots in comparison with microinjected quantum dots by focusing on their time-dependent accumulation and intracellular localization in different cell lines. Methods: The accumulation dynamics of nontargeted CdSe/ZnS carboxyl-coated quantum dots (emission peak 625 nm) was analyzed in NIH3T3, MCF-7, and HepG2 cells by applying the methods of confocal and steady-state fluorescence spectroscopy. Intracellular colocalization of the quantum dots was investigated by staining with Lysotracker®. Results: The uptake of quantum dots into cells was dramatically reduced at a low temperature (4°C), indicating that the process is energy-dependent. The uptake kinetics and imaging of intracellular localization of quantum dots revealed three accumulation stages of carboxyl-coated quantum dots at 37°C, ie, a plateau stage, growth stage, and a saturation stage, which comprised four morphological phases: adherence to the cell membrane; formation of granulated clusters spread throughout the cytoplasm; localization of granulated clusters in the perinuclear region; and formation of multivesicular body-like structures and their redistribution in the cytoplasm. Diverse quantum dots containing intracellular vesicles in the range of approximately 0.5–8 μm in diameter were observed in the cytoplasm, but none were found in the nucleus. Vesicles containing quantum dots formed multivesicular body-like structures in NIH3T3 cells after 24 hours of incubation, which were Lysotracker-negative in serum-free medium and Lysotracker-positive in complete medium. The microinjected quantum dots remained uniformly distributed in the cytosol for at least 24 hours. Conclusion: Natural uptake of quantum dots in cells occurs through three accumulation stages via a mechanism requiring energy. The sharp contrast of the intracellular distribution after microinjection of quantum dots in comparison with incubation as well as the limited transfer of quantum dots from vesicles into the cytosol and vice versa support the endocytotic origin of the natural uptake of quantum dots. Quantum dots with proteins adsorbed from the culture medium had a different fate in the final stage of accumulation from that of the protein-free quantum dots, implying different internalization pathways. PMID:23429995

Uncovering the Design Principle of Amino Acid-Derived Photoluminescent Biodots with Tailor-Made Structure-Properties and Applications for Cellular Bioimaging.

PubMed

Xu, Hesheng Victor; Zheng, Xin Ting; Zhao, Yanli; Tan, Yen Nee

2018-06-13

Natural amino acids possess side chains with different functional groups (R groups), which make them excellent precursors for programmable synthesis of biomolecule-derived nanodots (biodots) with desired properties. Herein, we report the first systematic study to uncover the material design rules of biodot synthesis from 20 natural α-amino acids via a green hydrothermal approach. The as-synthesized amino acid biodots (AA dots) are comprehensively characterized to establish a structure-property relationship between the amino acid precursors and the corresponding photoluminescent properties of AA dots. It was found that the amino acids with reactive R groups, including amine, hydroxyl, and carboxyl functional groups form unique C-O-C/C-OH and N-H bonds in the AA dots which stabilize the surface defects, giving rise to brightly luminescent AA dots. Furthermore, the AA dots were found to be amorphous and the length of the R group was observed to affect the final morphology (e.g., disclike nanostructure, nanowire, or nanomesh) of the AA dots, which in turn influence their photoluminescent properties. It is noteworthy to highlight that the hydroxyl-containing amino acids, that is, Ser and Thr, form the brightest AA dots with a quantum yield of 30.44% and 23.07%, respectively, and possess high photostability with negligible photobleaching upon continuous UV exposure for 3 h. Intriguingly, by selective mixing of Ser or Thr with another amino acid precursor, the resulting mixed AA dots could inherit unique properties such as improved photostability and significant red shift in their emission wavelength, producing enhanced green and red fluorescent intensity. Moreover, our cellular studies demonstrate that the as-synthesized AA dots display outstanding biocompatibility and excellent intracellular uptake, which are highly desirable for imaging applications. We envision that the material design rules discovered in this study will be broadly applicable for the rational selection of amino acid precursors in the tailored synthesis of biodots.

Theoretical study of polarization dependence of carrier-induced refractive index change of quantum dot.

PubMed

Miao, Qingyuan; Yang, Ziyi; Dong, Jianji; He, Ping-An; Huang, Dexiu

2018-02-05

The influences of dot material component, barrier material component, aspect ratio and carrier density on the refractive index changes of TE mode and TM mode of columnar quantum dot are analyzed, and a multiparameter adjustment method is proposed to realize low polarization dependence of refractive index change. Then the quantum dots with low polarization dependence of refractive index change (<1.5%) within C-band (1530 nm - 1565 nm) are designed, and it shows that quantum dots with different material parameters are anticipated to have similar characteristics of low polarization dependence.

A simple strategy for synthesizing highly luminescent carbon nanodots and application as effective down-shifting layers.

PubMed

Han, Xugen; Zhong, Sihua; Pan, Wei; Shen, Wenzhong

2015-02-13

We propose a novel strategy to prepare highly luminescent carbon nanodots (C-dots) by employing a hydrothermal method with citric acid as the carbon source and ethylenediamine as the nitrogen source, together with adding moderate ammonia water (AW) to achieve both appropriate inner structure and excellent N passivation. The effect of pH value and AW amount on the luminescence properties has been thoroughly investigated. The photoluminescence quantum yield of the resultant C-dots reaches as high as 84.8%, which is of 10.56% higher than that of the C-dots synthesized in the absence of AW in the reaction precursors. We have further combined the highest luminescent C-dots with polyvinyl alcohol to form luminescent down-shifting layers on silicon nanowire solar cells. An effective enhancement of short-circuit current density has been realized and the contribution of the down-shifting has been extracted quantitatively from the deterioration of surface reflectance and the gain of the optical absorption redistribution by means of a theoretical model on external quantum efficiency analysis.

Microwave-assisted synthesis of C-doped TiO2 and ZnO hybrid nanostructured materials as quantum-dots sensitized solar cells

NASA Astrophysics Data System (ADS)

Rangel-Mendez, Jose R.; Matos, Juan; Cházaro-Ruiz, Luis F.; González-Castillo, Ana C.; Barrios-Yáñez, Guillermo

2018-03-01

The microwave-assisted solvothermal synthesis of C-doped TiO2 and ZnO hybrid materials was performed. Saccharose, titanium isopropoxide and zinc acetate were used as organic and inorganic sources for the synthesis. The influence of temperature and reaction time on the textural and optoelectronic properties of the hybrid materials was verified. Carbon quantum-dots of TiO2 and ZnO nanostructured spheres were obtained in a second pot by controlled calcination steps of the precursor hybrid materials. A carefully characterization by adsorption-desorption N2 isotherms, XRD, XPS, SEM, UV-vis/DR and electro- and photo-electrochemistry properties of the carbon quantum-dots TiO2 and ZnO spheres was performed. The photoelectrochemical activity of TiO2-C and ZnO-C films proved to be dependent on the conditions of synthesis. It was found a red-shift in the energy band gap of the semiconductors with values of 3.02 eV and 3.13 eV for the TiO2-C and ZnO-C, respectively, clearly lower than those on bare semiconductors, which is associated with the C-doping effect. From the photo-electrochemistry characterization of C-doped TiO2 and ZnO films can be concluded that the present materials have potential applications as photoelectrodes for quantum-dots sensitized solar cells.

Acceptability and feasibility of mHealth and community-based directly observed antiretroviral therapy to prevent mother-to-child HIV transmission in South African pregnant women under Option B+: an exploratory study

PubMed Central

Nachega, Jean B; Skinner, Donald; Jennings, Larissa; Magidson, Jessica F; Altice, Frederick L; Burke, Jessica G; Lester, Richard T; Uthman, Olalekan A; Knowlton, Amy R; Cotton, Mark F; Anderson, Jean R; Theron, Gerhard B

2016-01-01

Objective To examine the acceptability and feasibility of mobile health (mHealth)/short message service (SMS) and community-based directly observed antiretroviral therapy (cDOT) as interventions to improve antiretroviral therapy (ART) adherence for preventing mother-to-child human immunodeficiency virus (HIV) transmission (PMTCT). Design and methods A mixed-method approach was used. Two qualitative focus group discussions with HIV-infected pregnant women (n=20) examined the acceptability and feasibility of two ART adherence interventions for PMTCT: 1) SMS text messaging and 2) patient-nominated cDOT supporters. Additionally, 109 HIV-infected, pregnant South African women (18–30 years old) receiving PMTCT services under single-tablet antiretroviral therapy regimen during pregnancy and breastfeeding and continuing for life (“Option B+”) were interviewed about mobile phone access, SMS use, and potential treatment supporters. Setting A community primary care clinic in Cape Town, South Africa. Participants HIV-infected pregnant women. Main outcomes Acceptability and feasibility of mHealth and cDOT interventions. Results Among the 109 women interviewed, individual mobile phone access and SMS use were high (>90%), and 88.1% of women were interested in receiving SMS ART adherence support messages such as reminders, motivation, and medication updates. Nearly all women (95%) identified at least one person close to them to whom they had disclosed their HIV status and would nominate as a cDOT supporter. Focus group discussions revealed that cDOT supporters and adherence text messages were valued, but some concerns regarding supporter time availability and risk of unintended HIV status disclosure were expressed. Conclusion mHealth and/or cDOT supporter as interventions to improve ART adherence are feasible in this setting. However, safe HIV status disclosure to treatment supporters and confidentiality of text messaging content about HIV and ART were deemed crucial. PMID:27175068

Room temperature solid-state synthesis of a conductive polymer for applications in stable I₂-free dye-sensitized solar cells.

PubMed

Kim, Byeonggwan; Koh, Jong Kwan; Kim, Jeonghun; Chi, Won Seok; Kim, Jong Hak; Kim, Eunkyoung

2012-11-01

A solid-state polymerizable monomer, 2,5-dibromo-3,4-propylenedioxythiophene (DBProDOT), was synthesized at 25 °C to produce a conducting polymer, poly(3,4-propylenedioxythiophene) (PProDOT). Crystallographic studies revealed a short interplane distance between DBProDOT molecules, which was responsible for polymerization at low temperature with a lower activation energy and higher exothermic reaction than 2,5-dibromo-3,4-ethylenedioxythiophene (DBEDOT) or its derivatives. Upon solid-state polymerization (SSP) of DBProDOT at 25 °C, PProDOT was obtained in a self-doped state with tribromide ions and an electrical conductivity of 0.05 S cm⁻¹, which is considerably higher than that of chemically-polymerized PProDOT (2×10⁻⁶ S cm⁻¹). Solid-state ¹³C NMR spectroscopy and DFT calculations revealed polarons in PProDOT and a strong perturbation of carbon nuclei in thiophenes as a result of paramagnetic broadening. DBProDOT molecules deeply penetrated and polymerized to fill nanocrystalline TiO₂ pores with PProDOT, which functioned as a hole-transporting material (HTM) for I₂-free solid-state dye-sensitized solar cells (ssDSSCs). With the introduction of an organized mesoporous TiO₂ (OM-TiO₂) layer, the energy conversion efficiency reached 3.5 % at 100 mW cm⁻², which was quite stable up to at least 1500 h. The cell performance and stability was attributed to the high stability of PProDOT, with the high conductivity and improved interfacial contact of the electrode/HTM resulting in reduced interfacial resistance and enhanced electron lifetime. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Crystal chemistry of elpidite from Khan Bogdo (Mongolia) and its K- and Rb-exchanged forms

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

Grigor'eva, A. A.; Zubkova, N. V., E-mail: nata_zubkova@rambler.ru; Pekov, I. V.

2011-09-15

Elpidite Na{sub 2}ZrSi{sub 6}O{sub 15} {center_dot} 3H{sub 2}O [space group Pbcm, a = 7.1312(12), b = 14.6853(12), and c = 14.6349(15) Angstrom-Sign ] from Khan Bogdo (Mongolia) and its K- and Rb-exchanged forms K{sub 1.78}Na{sub 0.16}H{sub 0.06}ZrSi{sub 6}O{sub 15} {center_dot} 0.85H{sub 2}O [Cmce, a = 14.054(3), b = 14.308(3), and c = 14.553(3) Angstrom-Sign ] and Na{sub 1.58}Rb{sub 0.2}H{sub 0.22}ZrSi{sub 6}O{sub 15} {center_dot} 2.69H{sub 2}O [Pbcm, a = 7.1280(10), b = 14.644(3), and c = 14.642(3) Angstrom-Sign ] that were obtained by cation exchange at 90 Degree-Sign C, as well as K{sub 1.84}Na{sub 0.11}H{sub 0.05}ZrSi{sub 6}O{sub 15} {center_dot} 0.91H{sub 2}Omore » [Cmce, a = 14.037(3), b = 14.226(3), and c = 14.552(3) Angstrom-Sign ] and Rb{sub 1.78}Na{sub 0.06}H{sub 0.16}ZrSi{sub 6}O{sub 15} {center_dot} 0.90H{sub 2}O [Cmce, a = 14.2999(12), b = 14.4408(15), and c = 14.7690(12) Angstrom-Sign ], obtained at 150 Degree-Sign C are studied by single-crystal X-ray diffraction and IR spectroscopy. The base of the structures is a heteropolyhedral Zr-Si-O framework whose cavities accommodate Na (K, Rb) cations and H{sub 2}O molecules.« less

DC power limitation of the heterojunction bipolar transistor with dot geometry: Effect of base potential distribution on thermal runaway

NASA Astrophysics Data System (ADS)

Liou, L. L.; Jenkins, T.; Huang, C. I.

1997-06-01

The d.c. power limitation of a conventional HBT with dot geometry was studied theoretically using combined electro-thermal and transmission line models. In most cases, the thermal runaway occurs at a power level lower than that set by the intrinsic electronic property of the device. The dependence of the d.c. thermal runaway threshold power density, Pmax, on the emitter dot radius and emitter ballast resistance was calculated. Increasing emitter dot radius lowers Pmax. Although ballast resistance increases Pmax, the effect reduces as the emitter dot radius increases. This is caused by the non-uniform potential distribution in the base layer. When thermal runaway is considered, the nonuniform base-emitter potential offsets the improvement of the power handling capability by the physical ballast resistance. Conventional HBTs with a large radius (greater than 4 μm) exhibit a small Pmax caused by thermal effect. This threshold power density can be increased drastically by using the thermal shunt technique.

Elimination of Bimodal Size in InAs/GaAs Quantum Dots for Preparation of 1.3-μm Quantum Dot Lasers

NASA Astrophysics Data System (ADS)

Su, Xiang-Bin; Ding, Ying; Ma, Ben; Zhang, Ke-Lu; Chen, Ze-Sheng; Li, Jing-Lun; Cui, Xiao-Ran; Xu, Ying-Qiang; Ni, Hai-Qiao; Niu, Zhi-Chuan

2018-02-01

The device characteristics of semiconductor quantum dot lasers have been improved with progress in active layer structures. Self-assembly formed InAs quantum dots grown on GaAs had been intensively promoted in order to achieve quantum dot lasers with superior device performances. In the process of growing high-density InAs/GaAs quantum dots, bimodal size occurs due to large mismatch and other factors. The bimodal size in the InAs/GaAs quantum dot system is eliminated by the method of high-temperature annealing and optimized the in situ annealing temperature. The annealing temperature is taken as the key optimization parameters, and the optimal annealing temperature of 680 °C was obtained. In this process, quantum dot growth temperature, InAs deposition, and arsenic (As) pressure are optimized to improve quantum dot quality and emission wavelength. A 1.3-μm high-performance F-P quantum dot laser with a threshold current density of 110 A/cm2 was demonstrated.

Elimination of Bimodal Size in InAs/GaAs Quantum Dots for Preparation of 1.3-μm Quantum Dot Lasers.

PubMed

Su, Xiang-Bin; Ding, Ying; Ma, Ben; Zhang, Ke-Lu; Chen, Ze-Sheng; Li, Jing-Lun; Cui, Xiao-Ran; Xu, Ying-Qiang; Ni, Hai-Qiao; Niu, Zhi-Chuan

2018-02-21

The device characteristics of semiconductor quantum dot lasers have been improved with progress in active layer structures. Self-assembly formed InAs quantum dots grown on GaAs had been intensively promoted in order to achieve quantum dot lasers with superior device performances. In the process of growing high-density InAs/GaAs quantum dots, bimodal size occurs due to large mismatch and other factors. The bimodal size in the InAs/GaAs quantum dot system is eliminated by the method of high-temperature annealing and optimized the in situ annealing temperature. The annealing temperature is taken as the key optimization parameters, and the optimal annealing temperature of 680 °C was obtained. In this process, quantum dot growth temperature, InAs deposition, and arsenic (As) pressure are optimized to improve quantum dot quality and emission wavelength. A 1.3-μm high-performance F-P quantum dot laser with a threshold current density of 110 A/cm 2 was demonstrated.

Physiological responses to cold (10° C) in men after six months' practice of yoga exercises

NASA Astrophysics Data System (ADS)

Selvamurthy, W.; Ray, U. S.; Hegde, K. S.; Sharma, R. P.

1988-09-01

A study was conducted on 30 healthy soldiers (age: 40 46 years) to assess the effect of selected yogic exercises (asanas) on some physiological responses to cold exposure. They were randomly divided into two groups of 15 each. One group performed regular physical exercises of physical training (PT), while the other group practised yogic exercises. At the end of 6 months of training, both the groups were exposed together to cold stress at 10°C for 2 h, and the following parameters were periodically monitored during cold exposure: heart rate ( fH), blood pressure ( BP), cardiac output(dot Q_c ), oral temperature (Tor), skin temperature ( T sk), respiratory rate ( fR), minute ventilation(dot V_E ), oxygen consumption(dot V_{O_2 } ), and shivering response by integrated electromyogram (EMG). There were progressive increases in BP, fR,dot V_E ,dot V_{O_2 } , anddot Q_c and decreases in fH, T or and T sk during cold exposure in both the groups. However, the decrease in T or and the increases indot V_{O_2 } anddot V_E were relatively lower ( P<0.01) in the yoga group as compared to the PT group. The shivering response appeared much earlier and was more intense in the PT group. These findings suggest that practice of yoga exercises may improve cold tolerance.

Majorana modes and Kondo effect in a quantum dot attached to a topological superconducting wire (Presentation Recording)

NASA Astrophysics Data System (ADS)

Vernek, Edson; Ruiz-Tijerina, David; da Silva, Luis D.; Egues, José Carlos

2015-09-01

Quantum dot attached to topological wires has become an interesting setup to study Majorana bound state in condensed matter[1]. One of the major advantage of using a quantum dot for this purpose is that it provides a suitable manner to study the interplay between Majorana bound states and the Kondo effect. Recently we have shown that a non-interacting quantum dot side-connected to a 1D topological superconductor and to metallic normal leads can sustain a Majorana mode even when the dot is empty. This is due to the Majorana bound state of the wire leaking into the quantum dot. Now we investigate the system for the case in which the quantum dot is interacting[3]. We explore the signatures of a Majorana zero-mode leaking into the quantum dot, using a recursive Green's function approach. We then study the Kondo regime using numerical renormalization group calculations. In this regime, we show that a "0.5" contribution to the conductance appears in system due to the presence of the Majorana mode, and that it persists for a wide range of the dot parameters. In the particle-hole symmetric point, in which the Kondo effect is more robust, the total conductance reaches 3e^2/2h, clearly indicating the coexistence of a Majorana mode and the Kondo resonance in the dot. However, the Kondo effect is suppressed by a gate voltage that detunes the dot from its particle-hole symmetric point as well as by a Zeeman field. The Majorana mode, on the other hand, is almost insensitive to both of them. We show that the zero-bias conductance as a function of the magnetic field follows a well-known universal curve. This can be observed experimentally, and we propose that this universality followed by a persistent conductance of 0.5,e^2/h are evidence for the presence of Majorana-Kondo physics. This work is supported by the Brazilians agencies FAPESP, CNPq and FAPEMIG. [1] A. Y. Kitaev, Ann.Phys. {bf 303}, 2 (2003). [2] E. Vernek, P.H. Penteado, A. C. Seridonio, J. C. Egues, Phys. Rev. B {bf 89}, 165314 (2014). [3] David A. Ruiz-Tijerina, E. Vernek, Luis G. G. V. Dias da Silva, J. C. Egues, arXiv:1412.1851 [cond-mat.mes-hall].

Transferências orbitais dentro do modelo quase bicircular no sistema Terra-Lua-Sol

NASA Astrophysics Data System (ADS)

Corrêa, A. A.; de Almeida Prado, A. F. B.; Stuchi, T. J.; Beaugé, C.

2003-08-01

O problema quase bicircular planar consiste na determinação da dinâmica de um corpo, de massa desprezível, que se move sob o campo gravitacional de três corpos. No caso estudado, o quarto corpo é considerado um satélite artificial e os demais são a Terra, a Lua e o Sol, formando o sistema de três corpos. Este modelo permite a construção de uma hamiltoniana similar a do problema restrito de três corpos (PRTC), incluindo termos periódicos não autônomos, provenientes da presença do Sol, portanto pode ser entendido como uma perturbação ao PRTC. Suas órbitas periódicas aparecem isoladas e possuem o mesmo período solar. Os pontos de equilíbrio colineares possuem o mesmo caráter de estabilidade linear dos pontos lagrangianos (L1, L2 e L3) do PRTC, sendo do tipo sela x centro x centro, instável na direção x e estáveis nas direções y e z. As órbitas periódicas tridimensionais ao redor do ponto colinear é chamada órbita Halo. O objetivo deste trabalho é determinar órbitas de transferências de baixo consumo de combustível para um veículo espacial partindo de uma órbita de estacionamento ao redor da Terra em direção a uma órbita Halo do ponto L1, situado entre a Terra e Lua. Esta tarefa pode ser transformada no problema de valor de contorno: dado um ponto inicial na órbita de estacionamento, um ponto final na órbita halo e o tempo de transferência, deseja-se obter a trajetória que liga estes dois pontos e que minimize os incrementos de velocidade do veículo. Essas transferências são realizadas baseadas no método de Lambert e analisadas de modo a fornecer um baixo consumo. Posteriormente, é feita uma comparação de consumo com as órbitas de transferência equivalentes do PRTC.

Corrosion and hydrogen pick-up behaviors of cladding and structural components in BWR high burnup 9x9 lead use assemblies

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

Miyashita, Toshiyasu; Nakae, Nobuo; Ogata, Keizo

The high burnup BWR 9x9 lead use fuel assemblies, which have been designed for maximum assembly burnup of 55 GWd/t in Japan, have been examined after irradiations to confirm the reliability of the current safety evaluation methodology, and to accumulate data to judge the adequacy to apply it to the future higher burnup fuel. After 3 and 5 cycle irradiations, post irradiation examinations were performed for both 9x9 Type-A and Type-B fuel assemblies. Both Type LUAs utilize Zry-2 claddings, while there are deviation in the contents of impurity and alloying elements between Type-A and Type-B, especially in Fe and Simore » concentration. Measured oxide thicknesses of fuel rods showed no significant difference between after 3 and 5 cycle irradiation except for some rods at corner position in Type B LUA. The axial profile of hydrogen concentration and oxide thickness for the corner rods in Type B LUA after 5 cycle irradiation had peaks at the second lowest span from the bottom. The maximum oxide thickness is about 50 {mu}m on the surface facing the bundle outside at the second lowest span and dense hydrides layer (Hydride rim) is observed in peripheral region of cladding showing unexpected high hydrogen concentration. The results of calculated thermal-hydraulic conditions show that the thermal neutron flux at the corner position was higher than the other position. On the other hand, the void fraction and the mass flux were relatively lower at the corner position. The oxide thickness on spacer band and spacer cell of Zry-2 increases from 3 to 5 cycle irradiations. Spacer band of Zry-4 showed significantly thick oxide after 5 cycle irradiations but Hydrogen concentration was relatively small in contrast its obviously thick oxide in comparison with Zry-2 spacer bands. The large increase in hydrogen concentration was measured in Zry-2 spacers after 5 cycle irradiations and the evaluated hydrogen pick-up rate also increased remarkably. (authors)« less

Effective Parallel Algorithm Animation

DTIC Science & Technology

1994-03-01

parallel computer. The system incorporates the 14 Parallel Processing System us" r User User UMe PMwuM Progra Propu Plropm ýData Dots Data Daft...that produce meaningful animations. The following sections outline characteristics 146 Animation 0 71 r 40 02 I 5 * *2! 4 Idle Bu~sy Send Recv 7...Event Simulation. Technical Report, Georgia Institute of Technology, 1992. 22. Garey, Michael R . and David S. Johnson. Computers and Intractability: A

78 FR 79058 - Proposed Information Collection Request; Notice of New Requirements and Procedures for Grant...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-27

...The DOT invites the public and other Federal agencies to comment on a revision to a previously approved information collection concerning new requirements and procedures for grant payment request submission. DOT will submit the proposed renewal of information collection request to the Office of Management and Budget (OMB) for review, as required by the Paperwork Reduction Act of 1995 (PRA) (44 U.S.C. 3506 (c)(2)(A)). This notice sets forth new requirements and procedures for grantees that submit and receive payments from DOT Operating Administrations (OAs).\\1\\ DOT is updating systems that support grant payments and there will be changes to the way grantees complete and submit payment requests. Simplifying the DOT grant payment process will save both the grantee and the Federal Government time and expense that come with paper-based grant application and payment administration. Note: At this time, this requirement is not applicable to DOT grant recipients requesting payment electronically through the National Highway Traffic Safety Administration's Grant Tracking System (GTS), the Federal Highway Administration's Rapid Approval State Payment System (RASPS), or Federal Transit Administration (FTA) grant recipients requesting payment through the Electronic Clearing House Operation System (ECHO-Web). ---------------------------------------------------------------------------

Platinum assisted by carbon quantum dots for methanol electro-oxidation

NASA Astrophysics Data System (ADS)

Pan, Dan; Li, Xingwei; Zhang, Aofeng

2018-01-01

Various types of fuel cells as clean and portable power sources show a great attraction, especially direct methanol fuel cell (DMFC) having high energy density, low operating temperature and convenient fuel storage. However, the preparation of low-cost Pt-based catalysts with satisfactory catalytic performance still faces many challenges for its commercialization on large scale. Here, Pt catalysts assisted by carbon quantum dots (CQDs) are reported. The synergistic effect of carbon quantum dots and Pt metals is similar to a bi-component catalyst, such as PtRu. First, carbon quantum dots derived from Vulcan XC-72 carbon black are synthesized by mixed acid etching. Then, carbon black (Vulcan XC-72) is soaked in carbon quantum dots solution for several days to obtain carbon black modified by carbon quantum dots (XC-72-CQDs). Finally, Pt catalysts are supported on XC-72-CQDs (Pt/XC-72-CQDs) through a simple chemical reduction method. For methanol electro-oxidation reaction, the catalytic performance of Pt/XC-72-CQDs is compared with commercial PtRu/C (30% Pt + 15% Ru). Results show that a typical product (Pt/XC-72-CQDs5) exhibits a better catalytic activity than PtRu/C. In cyclic voltammetry test, the specific activity of Pt/XC-72-CQDs5 is 1.06 mA cm-2 Pt and 477.6 mA mg-1 Pt, while that of PtRu/C is 0.77 mA cm-2 Pt and 280.6 mA mg-1 Pt.

A 5-mC Dot Blot Assay Quantifying the DNA Methylation Level of Chondrocyte Dedifferentiation In Vitro.

PubMed

Jia, Zhaofeng; Liang, Yujie; Ma, Bin; Xu, Xiao; Xiong, Jianyi; Duan, Li; Wang, Daping

2017-05-17

The dedifferentiation of hyaline chondrocytes into fibroblastic chondrocytes often accompanies monolayer expansion of chondrocytes in vitro. The global DNA methylation level of chondrocytes is considered to be a suitable biomarker for the loss of the chondrocyte phenotype. However, results based on different experimental methods can be inconsistent. Therefore, it is important to establish a precise, simple, and rapid method to quantify global DNA methylation levels during chondrocyte dedifferentiation. Current genome-wide methylation analysis techniques largely rely on bisulfite genomic sequencing. Due to DNA degradation during bisulfite conversion, these methods typically require a large sample volume. Other methods used to quantify global DNA methylation levels include high-performance liquid chromatography (HPLC). However, HPLC requires complete digestion of genomic DNA. Additionally, the prohibitively high cost of HPLC instruments limits HPLC's wider application. In this study, genomic DNA (gDNA) was extracted from human chondrocytes cultured with varying number of passages. The gDNA methylation level was detected using a methylation-specific dot blot assay. In this dot blot approach, a gDNA mixture containing the methylated DNA to be detected was spotted directly onto an N + membrane as a dot inside a previously drawn circular template pattern. Compared with other gel electrophoresis-based blotting approaches and other complex blotting procedures, the dot blot method saves significant time. In addition, dot blots can detect overall DNA methylation level using a commercially available 5-mC antibody. We found that the DNA methylation level differed between the monolayer subcultures, and therefore could play a key role in chondrocyte dedifferentiation. The 5-mC dot blot is a reliable, simple, and rapid method to detect the general DNA methylation level to evaluate chondrocyte phenotype.

Entanglement of Electron Spins in Two Coupled Quantum Dots

NASA Astrophysics Data System (ADS)

Chen, Yuanzhen; Webb, Richard

2004-03-01

We study the entanglement of electron spins in a coupled quantum dots system at 70 mK. Two quantum dots are fabricated in a GaAs/AlGaAs heterostructure containing a high mobility 2-D electron gas. The two dots can be tuned independently and the electron spins in the dots are coupled through an exchange interaction between them. An exchange gate is used to vary the height and width of a potential barrier between the two dots, thus controlling the strength of the exchange interaction. Electrons are injected to the coupled dots by two independent DC currents and the output of the dots is incident on a beam splitter, which introduces quantum interferences. Cross-correlations of the shot noise of currents from the two output channels are measured and compared with theory (1). *Work supported by LPS and ARDA under MDA90401C0903 and NSF under DMR 0103223. (1) Burkard, Loss, & Sukhorukov, Phys. Rev. B61, R16303 (2000).

Environmental Barrier Coatings Having a YSZ Top Coat

NASA Technical Reports Server (NTRS)

Lee, Kang N.; Gray, Hugh (Technical Monitor)

2002-01-01

Environmental barrier coatings (EBCs) with a Si bond coat, a yttria-stabilized zirconia (YSZ) top coat, and various intermediate coats were investigated. EBCs were processed by atmospheric pressure plasma spraying. The EBC durability was determined by thermal cycling tests in water vapor at 1300 C and 1400 C, and in air at 1400 C and 1500 C. EBCs with a mullite (3Al2O3 (dot) 2SiO2) + BSAS (1 - xBaO (dot) xSrO (dot) Al2O3 (dot) 2SiO2) intermediate coat were more durable than EBCs with a mullite intermediate coat, while EBCs with a mullite/BSAS duplex intermediate coat resulted in inferior durability. The improvement with a mullite + BSAS intermediate coat was attributed to enhanced compliance of the intermediate coat due to the addition of a low modulus BSAS second phase. Mullite + BSAS/YSZ and BSAS/YSZ interfaces produced a low melting (less than 1400 C) reaction product, which is expected to degrade the EBC performance by increasing the thermal conductivity. EBCs with a mullite + BSAS / graded mullite + YSZ intermediate coat showed the best durability among the EBCs investigated in this study. This improvement was attributed to diffused CTE (Coefficient of Thermal Expansion) mismatch stress and improved chemical stability due to the compositionally graded mullite+YSZ layer.

Photovoltaic Ge/Si quantum dot detectors operating in the mid-wave atmospheric window (3 to 5 μm)

PubMed Central

2012-01-01

Ge/Si quantum dots fabricated by molecular-beam epitaxy at 500°C are overgrown with Si at different temperatures Tcap, and effect of boron delta doping of Si barriers on the mid-infrared photoresponse was investigated. The photocurrent maximum shifts from 2.3 to 3.9 μm with increasing Tcapfrom 300°C to 750°C. Within the sample set, we examined devices with different positions of the δ-doping layer with respect to the dot plane, different distances between the δ-doping layer and the dot plane d, and different doping densities pB. All detectors show pronounced photovoltaic behavior implying the presence of an internal inversion asymmetry due to the placing dopants in the barriers. The best performance was achieved for the device with Tcap = 600°C, pB = 12 × 1011cm−2, and d = 5 nm in a photovoltaic regime. At a sample temperature of 90 K and no applied bias, a responsivity of 0.83 mA/W and detectivity of 8 × 1010 cm Hz1/2/W at λ = 3.4 μm were measured under normal incidence infrared radiation. PMID:22938028

Nanostructured Materials Developed for Solar Cells

NASA Technical Reports Server (NTRS)

Bailey, Sheila G.; Castro, Stephanie L.; Raffaelle, Ryne P.; Fahey, Stephen D.; Gennett, Thomas; Tin, Padetha

2004-01-01

There has been considerable investigation recently regarding the potential for the use of nanomaterials and nanostructures to increase the efficiency of photovoltaic devices. Efforts at the NASA Glenn Research Center have involved the development and use of quantum dots and carbon nanotubes to enhance inorganic and organic cell efficiencies. Theoretical results have shown that a photovoltaic device with a single intermediate band of states resulting from the introduction of quantum dots offers a potential efficiency of 63.2 percent. A recent publication extended the intermediate band theory to two intermediate bands and calculated a limiting efficiency of 71.7 percent. The enhanced efficiency results from converting photons of energy less than the band gap of the cell by an intermediate band. The intermediate band provides a mechanism for low-energy photons to excite carriers across the energy gap by a two-step process.

Efficient exciton generation in atomic passivated CdSe/ZnS quantum dots light-emitting devices

PubMed Central

Kang, Byoung-Ho; Lee, Jae-Sung; Lee, Sang-Won; Kim, Sae-Wan; Lee, Jun-Woo; Gopalan, Sai-Anand; Park, Ji-Sub; Kwon, Dae-Hyuk; Bae, Jin-Hyuk; Kim, Hak-Rin; Kang, Shin-Won

2016-01-01

We demonstrate the first-ever surface modification of green CdSe/ZnS quantum dots (QDs) using bromide anions (Br-) in cetyl trimethylammonium bromide (CTAB). The Br- ions reduced the interparticle spacing between the QDs and induced an effective charge balance in QD light-emitting devices (QLEDs). The fabricated QLEDs exhibited efficient charge injection because of the reduced emission quenching effect and their enhanced thin film morphology. As a result, they exhibited a maximum luminance of 71,000 cd/m2 and an external current efficiency of 6.4 cd/A, both significantly better than those of their counterparts with oleic acid surface ligands. In addition, the lifetime of the Br- treated QD based QLEDs is significantly improved due to ionic passivation at the QDs surface. PMID:27686147

Reflective photoluminescence fiber temperature probe based on the CdSe/ZnS quantum dot thin film

NASA Astrophysics Data System (ADS)

Wang, Helin; Yang, Aijun; Chen, Zhongshi; Geng, Yan

2014-08-01

A reflective fiber temperature sensor based on the optical temperature dependent characteristics of a quantum dots (QDs) thin film is developed by depositing the CdSe/ZnS core/shell quantum dots on the SiO2 glass substrates. As the temperature is changed from 30 to 200°C, the peak wavelengths of PL spectra from the sensing head increase linearly with the temperature, while the peak intensity and the full width at half maximum (FWHM) of PL spectra vary exponentially according to the specific physical law. Using the obtained temperature-dependent peak-wavelength shift, the average resolution of the designed fiber temperature sensor can reach 0.12 nm/°C, while it reaches 0.056 nm/°C according to the FWHM of PL spectrum.

Quality Evaluation of Coatings by Automatic Scratch Testing

DTIC Science & Technology

1989-11-01

MTL TR 89-98 IADII QUALITY EVALUATION OF COATINGS BY AUTOMATIC SCRATCH TESTING KIRIT J. BHANSALI LBRTR A1 U.S. ARMY MATERIALS TECHNOLOGY LABORATORY...distribution unlimited. LABORATORY COMMANO U.S. ARMY MATERIALS TECHNOLOGY LABORATORY PMUNKS wcamaauv LUaAMUv Watertown, Massachusetts 02172-0001 .o...Theo 7- Kattamis* 9 PEWNWING ORGANIZATION NAME AMO ADDRESS 1.PORUEEET RJC.TS AREA & WORK UNIT NUMSS U.S. Army Materials Technology Laboratory Watertown

Bacterially produced human B7-1 protein encompassing its complete extracellular domain maintains its costimulatory activity in vitro.

PubMed

Shen, W; Wang, Y; Geng, Y; Si, L

2000-08-01

To investigate which of the two immunoglobulin (Ig)-like domains, immunoglobulin variable region homologous domain IgV (hB7-1 IgV), or immunoglobulin constant region homologous domain IgC (hB7-1 IgC) on human B7-1 molecule contain the receptor binding sites, and to evaluate if the B7-1 molecule expressed in bacteria has biological activity. PCR was used to amplify three fragments of hB7-1 IgV, hB7-1 IgC and complete extracellular region of human B7-1 containing both the IgV and IgC domains (hB7-1 IgV + IgC). Three recombinants, pQE9-hB7-1 IgV, pQE9-hB7-1 IgC and pQE9-Hb7-1 (IgV + IgC) were generated by cloning the PCR products into a prokaryote expression plasmid (pQE-9) and were introduced into the host stain M15. The relevant target hexahistidine-tagged proteins were identified by SDS-PAGE and Western blotting. With the presence of the first signal imitated by anti-CD3 antibody, T cell activation was observed by exposing purified T lymphocytes to each soluble form of the three bacterially-produced human B7-1 proteins and [3H]-TdR incorporation. Three recombinant proteins of human B7-1, hB7-1 IgV, hB7-1 IgC and hB7-1 (IgV + IgC) were produced and detected in both soluble and inclusive body forms from engineered bacterial cells. With the presence of anti-CD3 antibody, T lymphocytes proliferated when co-stimulated by bacterially produced hB7-1 (IgV + IgC), but not by either hB7-1 IgV or hB7-1 IgC. Functional glycoprotein human B7-1 could be produced in bacterial cells. Both extracellular immunoglobulin-like domains are necessary for B7-1 to react with its counter receptors.

PRISM3 DOT1 Atlantic Basin Reconstruction

USGS Publications Warehouse

Dowsett, Harry; Robinson, Marci; Dwyer, Gary S.; Chandler, Mark; Cronin, Thomas

2006-01-01

PRISM3 DOT1 (Pliocene Research, Interpretation and Synoptic Mapping 3, Deep Ocean Temperature 1) provides a three-dimensional temperature reconstruction for the mid-Pliocene Atlantic basin, the first of several regional data sets that will comprise a global mid-Pliocene reconstruction. DOT1 is an alteration of modern temperature values for the Atlantic Ocean in 4 degree x 5 degree cells in 13 depth layers for December 1 based on Mg/Ca-derived BWT estimates from seventeen DSDP and ODP Sites and SST estimates from the PRISM2 reconstruction (Dowsett et al., 1999). DOT1 reflects a vaguely modern circulation system, assuming similar processes of deep-water formation; however, North Atlantic Deep Water (NADW) production is increased, and Antarctic Bottom Water (AABW) production is decreased. Pliocene NADW was approximately 2 degreesC warmer than modern temperatures, and Pliocene AABW was approximately 0.3 degreesC warmer than modern temperatures.

Impact of threading dislocation density on the lifetime of InAs quantum dot lasers on Si

NASA Astrophysics Data System (ADS)

Jung, Daehwan; Herrick, Robert; Norman, Justin; Turnlund, Katherine; Jan, Catherine; Feng, Kaiyin; Gossard, Arthur C.; Bowers, John E.

2018-04-01

We investigate the impact of threading dislocation density on the reliability of 1.3 μm InAs quantum dot lasers epitaxially grown on Si. A reduction in the threading dislocation density from 2.8 × 108 cm-2 to 7.3 × 106 cm-2 has improved the laser lifetime by about five orders of magnitude when aged continuous-wave near room temperature (35 °C). We have achieved extrapolated lifetimes (time to double initial threshold) more than 10 × 106 h. An accelerated laser aging test at an elevated temperature (60 °C) reveals that p-modulation doped quantum dot lasers on Si retain superior reliability over unintentionally doped ones. These results suggest that epitaxially grown quantum dot lasers could be a viable approach to realize a reliable, scalable, and efficient light source on Si.

A Bridging Water Anchors the Tethered 5-(3-Aminopropyl)-2′-deoxyuridine Amine in the DNA Major Groove Proximate to the N+2 C·G Base Pair: Implications for Formation of Interstrand 5′-GNC-3′ Cross-Links by Nitrogen Mustards

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

Wang, Feng; Li, Feng; Ganguly, Manjori

2008-11-14

Site-specific insertion of t-(3-aminopropyl)-2'-deoxyuridine (Z3dU) and 7-deaza-dG into the Dickerson-Drew dodecamers 5'-d(C{sup 1}G{sup 2}C{sup 3}G{sup 4}A{sup 5}A{sup 6}T{sup 7}T{sup 8}C{sup 9}{und Z}{sup 10}C{sup 11}G{sup 12})-3'{center_dot}5'-d (C{sup 13}G{sup 14}C{sup 15}G{sup 16}A{sup 17}A{sup 18}T{sup 19}T{sup 20}C{sup 21}{und Z}{sup 22}C{sup 23}G{sup 24})-3' (named DDD{sup Z10}) and 5'-d(C{sup 1}G{sup 2}C{sup 3}G{sup 4}A{sup 5}A{sup 6}T{sup 7}{und X}{sup 20}C{sup 21}{und Z}{sup 22}C{sup 23}G{sup 24})-3' (named DDD{sup 2+Z10}) (X = 73dU; Z = 7-deaza-dG) suggests a mechanism underlying the formation of interstrand N+2 DNA cross-links by nitrogen mustards, e.g., melphalan and mechlorethamine. Analysis of the DDD{sup 2+Z10} duplex reveals that the tethered cations at base pairs A{supmore » 5}{center_dot}X{sup 20} and X{sup 8}{center_dot}A{sup 17} extend within the major groove in the 3'-direction, toward conserved Mg{sup 2+} binding sites located adjacent to N+2 base pairs C{sup 3}{center_dot}Z{sup 22} and Z{sup 10}{center_dot}C{sup 15}. Bridging waters located between the tethered amines and either Z{sup 10} or Z{sup 22} O{sup 6} stabilize the tethered cations and allow interactions with the N + 2 base pairs without DNA bending. Incorporation of 7-deaza-dG into the DDD{sup 2+Z10} duplex weakens but does not eliminate electrostatic interactions between tethered amines and Z{sup 10} O{sup 6} and Z{sup 22} O{sup 6}. The results suggest a mechanism by which tethered N7-dG aziridinium ions, the active species involved in formation of interstrand 5'-GNC-3' cross-links by nitrogen mustards, modify the electrostatics of the major groove and position the aziridinium ions proximate to the major groove edge of the N+2 C{center_dot}G base pair, facilitating interstrand cross-linking.« less

Ratiometric photoluminescence sensing based on Ti3C2 MXene quantum dots as an intracellular pH sensor.

PubMed

Chen, Xu; Sun, Xueke; Xu, Wen; Pan, Gencai; Zhou, Donglei; Zhu, Jinyang; Wang, He; Bai, Xue; Dong, Biao; Song, Hongwei

2018-01-18

Intracellular pH sensing is of importance and can be used as an indicator for monitoring the evolution of various diseases and the health of cells. Here, we developed a new class of surface-functionalized MXene quantum dots (QDs), Ti 3 C 2 , by the sonication cutting and hydrothermal approach and further explored their intracellular pH sensing. The functionalized Ti 3 C 2 QDs exhibit bright excitation-dependent blue photoluminescence (PL) originating from the size effect and surface defects. Meanwhile, Ti 3 C 2 QDs demonstrate a high PL response induced by the deprotonation of the surface defects. Furthermore, combining the highly pH sensitive Ti 3 C 2 QDs with the pH insensitive [Ru(dpp) 3 ]Cl 2 , we developed a ratiometric pH sensor to quantitatively monitor the intracellular pH values. These novel MXene quantum dots can serve as a promising platform for developing practical fluorescent nanosensors.

One-step synthesis of multi-emission carbon nanodots for ratiometric temperature sensing

NASA Astrophysics Data System (ADS)

Nguyen, Vanthan; Yan, Lihe; Xu, Huanhuan; Yue, Mengmeng

2018-01-01

Measuring temperature with greater precision at localized small length scales or in a nonperturbative manner is a necessity in widespread applications, such as integrated photonic devices, micro/nano electronics, biology, and medical diagnostics. To this context, use of nanoscale fluorescent temperature probes is regarded as the most promising method for temperature sensing because they are noninvasive, accurate, and enable remote micro/nanoscale imaging. Here, we propose a novel ratiometric fluorescent sensor for nanothermometry using carbon nanodots (C-dots). The C-dots were synthesized by one-step method using femtosecond laser ablation and exhibit unique multi-emission property due to emissions from abundant functional groups on its surface. The as-prepared C-dots demonstrate excellent ratiometric temperature sensing under single wavelength excitation that achieves high temperature sensitivity with a 1.48% change per °C ratiometric response over wide-ranging temperature (5-85 °C) in aqueous buffer. The ratiometric sensor shows excellent reversibility and stability, holding great promise for the accurate measurement of temperature in many practical applications.

78 FR 55330 - Policy Regarding Airport Rates and Charges

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-10

... Printing Office's Web page at http://www.access.gpo.gov/su_docs/aces/aces140.html . Authority for This... Transport Ass'n of America v. DOT, 119 F.3d 38, amended by 129 F.3d 625 (D.C. Cir. 1997). In July 2008... of Columbia Circuit, Air Transport Ass'n v. DOT, 613 F.3d 206 (D.C. Cir. 2010). In 2012, Congress...

Stability and Tolerance to Optical Feedback of Quantum Dot Lasers

DTIC Science & Technology

2012-01-01

Libre de Bruxelles Optique Nonlineaire Theorique Campus Plaine, C.P. 213 Bruxelles, Belgium 1050 EOARD GRANT 09-3068 Report Date...Universite Libre de Bruxelles Optique Nonlineaire Theorique Campus Plaine, C.P. 213 Bruxelles, Belgium 1050 8. PERFORMING ORGANIZATION...Universite Libre de Bruxelles as follows: Quantum dot (QD) lasers have attracted a lot of attention because of their low threshold currents, low line

Performance Characteristics of Borate Fatty Acid Formulations as Mold Inhibitors

Treesearch

Robert D. Coleman; Vina Yang; Carol A. Clausen

2013-01-01

The combination of boric acid (BA) or disodium octaborate tetrahydrate (DOT) and a fatty acid (FA) such as heptanoic, octanoic, and nonanoic acids (C7–C9) is an effective treatment solution for protecting wood structures against mold. BA or DOT alone have substantial potency against insects and decay fungi, but have negligible or no mold inhibitor activity. However,...

Angular dependence of dose sensitivity of nanoDot optically stimulated luminescent dosimeters in different radiation geometries

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

Jursinic, Paul A., E-mail: pjursinic@wmcc.org

2015-10-15

Purpose: A type of in vivo dosimeter, an optically stimulated luminescent dosimeter, OSLD, may have dose sensitivity that depends on the angle of incidence of radiation. This work measures how angular dependence of a nanoDot changes with the geometry of the phantom in which irradiation occurs and with the intrinsic structure of the nanoDot. Methods: The OSLDs used in this work were nanoDot dosimeters (Landauer, Inc., Glenwood, IL), which were read with a MicroStar reader (Landauer, Inc., Glenwood, IL). Dose to the OSLDs was delivered by 6 MV x-rays. NanoDots with various intrinsic sensitivities were irradiated in numerous phantoms thatmore » had geometric shapes of cylinders, rectangles, and a cube. Results: No angular dependence was seen in cylindrical phantoms, cubic phantoms, or rectangular phantoms with a thickness to width ratio of 0.3 or 1.5. An angular dependence of 1% was observed in rectangular phantoms with a thickness to width of 0.433–0.633. A group of nanoDots had sensitive layers with mass density of 2.42–2.58 g/cm{sup 3} and relative sensitivity of 0.92–1.09 and no difference in their angular dependence. Within experimental uncertainty, nanoDot measurements agree with a parallel-plate ion chamber at a depth of maximum dose. Conclusions: When irradiated in cylindrical, rectangular, and cubic phantoms, nanoDots show a maximum angular dependence of 1% or less at an incidence angle of 90°. For a sample of 78 new nanoDots, the range of their relative intrinsic sensitivity is 0.92–1.09. For a sample of ten nanoDots, on average, the mass in the sensitive layer is 73.1% Al{sub 2}O{sub 3}:C and 26.9% polyester. The mass density of the sensitive layer of a nanoDot disc is between 2.42 and 2.58 g/cm{sup 3}. The angular dependence is not related to Al{sub 2}O{sub 3}:C loading of the nanoDot disc. The nanoDot at the depth of maximum dose has no more angular dependence than a parallel-plate ion chamber.« less

Quantum dots transparent display (QDs-TPD) using a liquid QDs layer and N2 barrier discharge

NASA Astrophysics Data System (ADS)

Kim, Hong Tak; Lee, Sung-Youp; Sohn, Sang Ho

2017-07-01

Quantum dots transparent display (QDs-TPD) was realized using a liquid QDs layer and N2 barrier discharge panel. In the N2 discharge, the 2nd+ lines of N2 in the range of 300 - 400 nm (C3Πu - B3Πg), and the 1st- lines of N2+ at 391.4 and 427.8 nm (B2Σu+ - X2 Σg+) were mainly observed, while the visible emission lines were rarely observed. This implies the N2 discharge is suitable for the excitation source of the QDs, due to the strong ultra-violet radiations and the weak visible emissions. The emission centers for red, green, and blue color in QDs-TPD were positioned at 452, 540, and 638 nm, respectively, and the N2 emission peaks were seldom observed in the visible region. The transmittance of QDs-TPD was approximately 40% in the visible region and the luminescence was about 70 cd/m2. The CIE (x, y) coordinates of red, green, and blue colors were (0.670, 0.309), (0.378, 0.640), and (0.183, 0.118), respectively, and the color gamut was 71% of a NTSC standard. Thus, the QDs-TPD is expected as a way for realizing the TPD, due to its good transparency, excellent visibility, wide viewing-angle, aesthetical design, low cost production, and good scalability to large sizes.

Notch filtering the nuclear environment of a spin qubit.

PubMed

Malinowski, Filip K; Martins, Frederico; Nissen, Peter D; Barnes, Edwin; Cywiński, Łukasz; Rudner, Mark S; Fallahi, Saeed; Gardner, Geoffrey C; Manfra, Michael J; Marcus, Charles M; Kuemmeth, Ferdinand

2017-01-01

Electron spins in gate-defined quantum dots provide a promising platform for quantum computation. In particular, spin-based quantum computing in gallium arsenide takes advantage of the high quality of semiconducting materials, reliability in fabricating arrays of quantum dots and accurate qubit operations. However, the effective magnetic noise arising from the hyperfine interaction with uncontrolled nuclear spins in the host lattice constitutes a major source of decoherence. Low-frequency nuclear noise, responsible for fast (10 ns) inhomogeneous dephasing, can be removed by echo techniques. High-frequency nuclear noise, recently studied via echo revivals, occurs in narrow-frequency bands related to differences in Larmor precession of the three isotopes 69 Ga, 71 Ga and 75 As (refs 15,16,17). Here, we show that both low- and high-frequency nuclear noise can be filtered by appropriate dynamical decoupling sequences, resulting in a substantial enhancement of spin qubit coherence times. Using nuclear notch filtering, we demonstrate a spin coherence time (T 2 ) of 0.87 ms, five orders of magnitude longer than typical exchange gate times, and exceeding the longest coherence times reported to date in Si/SiGe gate-defined quantum dots.

Effects of annealing on performances of 1.3-μm InAs-InGaAs-GaAs quantum dot electroabsorption modulators

PubMed Central

2013-01-01

In this work, we investigated the effects of quantum dot (QD) annealing (as-grown, 600°C-annealed, and 750°C-annealed) on the preliminary performances of 1.3-μm InAs-InGaAs-GaAs quantum dot electroabsorption modulators (QD-EAMs). Both extinction ratio and insertion loss were found to vary inversely with the annealing temperature. Most importantly, the 3-dB response of the 750°C-annealed lumped-element QD-EAM was found to be 1.6 GHz at zero reverse bias voltage - the lowest reverse bias voltage reported. We believe that this work will be beneficial to researchers working on on-chip integration of QD-EAMs with other devices since energy consumption will be an important consideration. PMID:23388169

Room-temperature phosphorescence logic gates developed from nucleic acid functionalized carbon dots and graphene oxide

NASA Astrophysics Data System (ADS)

Gui, Rijun; Jin, Hui; Wang, Zonghua; Zhang, Feifei; Xia, Jianfei; Yang, Min; Bi, Sai; Xia, Yanzhi

2015-04-01

Room-temperature phosphorescence (RTP) logic gates were developed using capture ssDNA (cDNA) modified carbon dots and graphene oxide (GO). The experimental results suggested the feasibility of these developed RTP-based ``OR'', ``INHIBIT'' and ``OR-INHIBIT'' logic gate operations, using Hg2+, target ssDNA (tDNA) and doxorubicin (DOX) as inputs.Room-temperature phosphorescence (RTP) logic gates were developed using capture ssDNA (cDNA) modified carbon dots and graphene oxide (GO). The experimental results suggested the feasibility of these developed RTP-based ``OR'', ``INHIBIT'' and ``OR-INHIBIT'' logic gate operations, using Hg2+, target ssDNA (tDNA) and doxorubicin (DOX) as inputs. Electronic supplementary information (ESI) available: All experimental details, Part S1-3, Fig. S1-6 and Table S1. See DOI: 10.1039/c4nr07620f

Luminescent Quantum Dots as Ultrasensitive Biological Labels

NASA Astrophysics Data System (ADS)

Nie, Shuming

2000-03-01

Highly luminescent semiconductor quantum dots have been covalently coupled to biological molecules for use in ultrasensitive biological detection. This new class of luminescent labels is considerably brighter and more resistant againt photobleaching in comparison with organic dyes. Quantum dots labeled with the protein transferrin undergo receptor-mediated endocytosis (RME) in cultured HeLa cells, and those dots that were conjugated to immunomolecules recognize specific antibodies or antigens. In addition, we show that DNA functionalized quantum dots can be used to target specific genes by hybridization. We expect that quantum dot bioconjugates will have a broad range of biological applications, such as ligand-receptor interactions, real-time monitoring of molecular trafficking inside living cells, multicolor fluorescence in-situ hybridization (FISH), high-sensitivity detection in miniaturized devices (e.g., DNA chips), and fluorescent tagging of combinatorial chemical libraries. A potential clinical application is the use of quantum dots for ultrasensitive viral RNA detection, in which as low as 100 copies of hepatitis C and HIV viruses per ml blood should be detected.

Anticipatory versus reactive spatial attentional bias to threat.

PubMed

Gladwin, Thomas E; Möbius, Martin; McLoughlin, Shane; Tyndall, Ian

2018-05-10

Dot-probe or visual probe tasks (VPTs) are used extensively to measure attentional biases. A novel variant termed the cued VPT (cVPT) was developed to focus on the anticipatory component of attentional bias. This study aimed to establish an anticipatory attentional bias to threat using the cVPT and compare its split-half reliability with a typical dot-probe task. A total of 120 students performed the cVPT task and dot-probe tasks. Essentially, the cVPT uses cues that predict the location of pictorial threatening stimuli, but on trials on which probe stimuli are presented the pictures do not appear. Hence, actual presentation of emotional stimuli did not affect responses. The reliability of the cVPT was higher at most cue-stimulus intervals and was .56 overall. A clear anticipatory attentional bias was found. In conclusion, the cVPT may be of methodological and theoretical interest. Using visually neutral predictive cues may remove sources of noise that negatively impact reliability. Predictive cues are able to bias response selection, suggesting a role of predicted outcomes in automatic processes. © 2018 The British Psychological Society.

Gamma Radiation Dose Rate in Air due to Terrestrial Radionuclides in Southern Brazil: Synthesis by Geological Units and Lithotypes Covered by the Serra do Mar Sul Aero-Geophysical Project

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

Bastos, Rodrigo O.; Appoloni, Carlos R.; Pinese, Jose P. P.

2008-08-07

The absorbed dose rates in air due to terrestrial radionuclides were estimated from aerial gamma spectrometric data for an area of 48,600 km{sup 2} in Southern Brazil. The source data was the Serra do Mar Sul Aero-Geophysical Project back-calibrated in a cooperative work among the Geological Survey of Brazil, the Geological Survey of Canada, and Paterson, Grant and Watson Ltd. The concentrations of eU (ppm), eTh (ppm) and K (%) were converted to dose rates in air (nGy{center_dot}h{sup -1}) by accounting for the contribution of each element's concentration. Regional variation was interpreted according to lithotypes and a synthesis was performedmore » according to the basic geological units present in the area. Higher values of total dose were estimated for felsic igneous and metamorphic rocks, with average values varying up to 119{+-}24 nGy{center_dot}h{sup -1}, obtained by Anitapolis syenite body. Sedimentary, metasedimentary and metamafic rocks presented the lower dose levels, and some beach deposits reached the lowest average total dose, 18.5{+-}8.2 nGy{center_dot}h{sup -1}. Thorium gives the main average contribution in all geological units, the highest value being reached by the nebulitic gneisses of Atuba Complex, 71{+-}23 nGy{center_dot}h{sup -1}. Potassium presents the lowest average contribution to dose rate in 53 of the 72 units analyzed, the highest contribution being obtained by intrusive alkaline bodies (28{+-}12 nGy{center_dot}h{sup -1}). The general pattern of geographic dose distribution respects well the hypotheses on geo-physicochemical behavior of radioactive elements.« less

Interactions between N-acetyl-L-cysteine protected CdTe quantum dots and doxorubicin through spectroscopic method

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

Yang, Xiupei, E-mail: xiupeiyang@163.com; College of Chemistry and Chemical Engineering, China West Normal University, Nanchong 637000; Lin, Jia

2015-06-15

Highlights: • CdTe quantum dots with the diameter of 3–5 nm were synthesized in aqueous solution. • The modified CdTe quantum dots showed well fluorescence properties. • The interaction between the CdTe quantum dots and doxorubicin (DR) was investigated. - Abstract: N-acetyl-L-cysteine protected cadmium telluride quantum dots with a diameter of 3–5 nm were synthesized in aqueous solution. The interaction between N-acetyl-L-cysteine/cadmium telluride quantum dots and doxorubicin was investigated by ultraviolet–visible absorption and fluorescence spectroscopy at physiological conditions (pH 7.2, 37 °C). The results indicate that electron transfer has occurred between N-acetyl-L-cysteine/cadmium telluride quantum dots and doxorubicin under light illumination.more » The quantum dots react readily with doxorubicin to form a N-acetyl-L-cysteine/cadmium telluride-quantum dots/doxorubicin complex via electrostatic attraction between the −NH{sub 3}{sup +} moiety of doxorubicin and the −COO{sup −} moiety of N-acetyl-L-cysteine/cadmium telluride quantum dots. The interaction of N-acetyl-L-cysteine/cadmium telluride-quantum dots/doxorubicin complex with bovine serum albumin was studied as well, showing that the complex might induce the conformation change of bovine serum due to changes in microenvironment of bovine serum.« less

High-Speed GPU-Based Fully Three-Dimensional Diffuse Optical Tomographic System

PubMed Central

Saikia, Manob Jyoti; Kanhirodan, Rajan; Mohan Vasu, Ram

2014-01-01

We have developed a graphics processor unit (GPU-) based high-speed fully 3D system for diffuse optical tomography (DOT). The reduction in execution time of 3D DOT algorithm, a severely ill-posed problem, is made possible through the use of (1) an algorithmic improvement that uses Broyden approach for updating the Jacobian matrix and thereby updating the parameter matrix and (2) the multinode multithreaded GPU and CUDA (Compute Unified Device Architecture) software architecture. Two different GPU implementations of DOT programs are developed in this study: (1) conventional C language program augmented by GPU CUDA and CULA routines (C GPU), (2) MATLAB program supported by MATLAB parallel computing toolkit for GPU (MATLAB GPU). The computation time of the algorithm on host CPU and the GPU system is presented for C and Matlab implementations. The forward computation uses finite element method (FEM) and the problem domain is discretized into 14610, 30823, and 66514 tetrahedral elements. The reconstruction time, so achieved for one iteration of the DOT reconstruction for 14610 elements, is 0.52 seconds for a C based GPU program for 2-plane measurements. The corresponding MATLAB based GPU program took 0.86 seconds. The maximum number of reconstructed frames so achieved is 2 frames per second. PMID:24891848

High-Speed GPU-Based Fully Three-Dimensional Diffuse Optical Tomographic System.

PubMed

Saikia, Manob Jyoti; Kanhirodan, Rajan; Mohan Vasu, Ram

2014-01-01

We have developed a graphics processor unit (GPU-) based high-speed fully 3D system for diffuse optical tomography (DOT). The reduction in execution time of 3D DOT algorithm, a severely ill-posed problem, is made possible through the use of (1) an algorithmic improvement that uses Broyden approach for updating the Jacobian matrix and thereby updating the parameter matrix and (2) the multinode multithreaded GPU and CUDA (Compute Unified Device Architecture) software architecture. Two different GPU implementations of DOT programs are developed in this study: (1) conventional C language program augmented by GPU CUDA and CULA routines (C GPU), (2) MATLAB program supported by MATLAB parallel computing toolkit for GPU (MATLAB GPU). The computation time of the algorithm on host CPU and the GPU system is presented for C and Matlab implementations. The forward computation uses finite element method (FEM) and the problem domain is discretized into 14610, 30823, and 66514 tetrahedral elements. The reconstruction time, so achieved for one iteration of the DOT reconstruction for 14610 elements, is 0.52 seconds for a C based GPU program for 2-plane measurements. The corresponding MATLAB based GPU program took 0.86 seconds. The maximum number of reconstructed frames so achieved is 2 frames per second.

A Virtual Reality Exposure Therapy Application for Iraq War Post Traumatic Stress Disorder

DTIC Science & Technology

2006-01-01

denial of social problems. Prior to the availability of VR therapy applications, the existing standard of care for PTSD was imaginal exposure...The application is built on ICT’s FlatWorld Simulation Control Architecture (FSCA) [13]. The FSCA enables a network -centric system of client displays...client-side interaction despite potential network delays. FCSA scripting is based on the Lua programming language [14] and provides facilities for real

Temperature Sensitivity of Water-Soluble CdTe and CdSe/ZnS Quantum Dots Incorporated into Biopolymer Submicron Particles

NASA Astrophysics Data System (ADS)

Slyusarenko, N. V.; Gerasimova, M. A.; Slabko, V. V.; Slyusareva, E. A.

2017-07-01

Polymer particles with sizes 0.3-0.4 μm are synthesized based on chitosan and chondroitin sulfate with incorporated CdTe (core) and CdSe/ZnS (core-shell) quantum dots. Their morphological and spectral properties are investigated by the methods of dynamic scattering, electron microscopy, and absorption and luminescence spectroscopy at temperatures from 10 to 80°C. Spectral effects associated with a change in temperature (a red shift and a decrease in the amplitude of the photoluminescence spectrum) can be explained by the temperature expansion of the quantum dots and activation of surface traps. It is shown that the temperature sensitivity of spectra of the quantum dots incorporated into the biopolymer particles is not less than in water. To develop an optical temperature sensor, the core quantum dots are more preferable than the core-shell quantum dots.

Spectral properties of finite two dimensional quantum dot arrays.

NASA Astrophysics Data System (ADS)

Cota, Ernesto; Ramírez, Felipe; Ulloa, Sergio E.

1997-08-01

Motivated by recent proposed geometries in cellular automata, we study arrays of four or five coupled quantum dots located at the corners and at the center of a square. We calculate the addition spectrum for dots with equal or different sizes at each site and compare with the case of linear arrays. We obtain the numerically exact solution for arrays with two electrons and study the properties of this system as a cell or building block of quantum dot cellular automata. We obtain the ``polarization" for each state and discuss its possible use as a two-state system or ``qubit," as proposed recently(C. S. Lent, P. D. Tougaw, and W. Porod, Appl. Phys. Lett. 62) 714, (1993). An extended Hubbard Hamiltonian is used which takes into account quantum confinement, intra- an inter-dot Coulomb interaction as well as tunneling between neighboring dots.

Spectral properties of finite two dimensional quantum dot arrays.

NASA Astrophysics Data System (ADS)

Ramirez, Felipe; Cota, Ernesto; Ulloa, Sergio E.

1997-03-01

Motivated by recent proposed geometries in cellular automata, we study arrays of four or five coupled quantum dots located at the corners and at the center of a square. We calculate the addition spectrum for dots with equal or different sizes at each site and compare with the case of linear arrays. We obtain the numerically exact solution for arrays with two electrons and study the properties of this system as a cell or building block of quantum dot cellular automata. We obtain the ``polarization" for each state and discuss its possible use as a two-state system or ``qubit," as proposed recently(C. S. Lent, P. D. Tougaw, and W. Porod, Appl. Phys. Lett. 62) 714, (1993). An extended Hubbard Hamiltonian is used which takes into account quantum confinement, intra- an inter-dot Coulomb interaction as well as tunneling between neighboring dots.

Malic Acid Carbon Dots: From Super-resolution Live-Cell Imaging to Highly Efficient Separation.

PubMed

Zhi, Bo; Cui, Yi; Wang, Shengyang; Frank, Benjamin P; Williams, Denise N; Brown, Richard P; Melby, Eric S; Hamers, Robert J; Rosenzweig, Zeev; Fairbrother, D Howard; Orr, Galya; Haynes, Christy L

2018-06-15

As-synthesized malic acid carbon dots are found to possess photoblinking properties that are outstanding and superior compared to those of conventional dyes. Considering their excellent biocompatibility, malic acid carbon dots are suitable for super-resolution fluorescence localization microscopy under a variety of conditions, as we demonstrate in fixed and live trout gill epithelial cells. In addition, during imaging experiments, the so-called "excitation wavelength-dependent" emission was not observed for individual as-made malic acid carbon dots, which motivated us to develop a time-saving and high-throughput separation technique to isolate malic acid carbon dots into fractions of different particle size distributions using C 18 reversed-phase silica gel column chromatography. This post-treatment allowed us to determine how particle size distribution influences the optical properties of malic acid carbon dot fractions, that is, optical band gap energies and photoluminescence behaviors.

Atomistic theory of excitonic fine structure in InAs/InP nanowire quantum dot molecules

NASA Astrophysics Data System (ADS)

Świderski, M.; Zieliński, M.

2017-03-01

Nanowire quantum dots have peculiar electronic and optical properties. In this work we use atomistic tight binding to study excitonic spectra of artificial molecules formed by a double nanowire quantum dot. We demonstrate a key role of atomistic symmetry and nanowire substrate orientation rather than cylindrical shape symmetry of a nanowire and a molecule. In particular for [001 ] nanowire orientation we observe a nonvanishing bright exciton splitting for a quasimolecule formed by two cylindrical quantum dots of different heights. This effect is due to interdot coupling that effectively reduces the overall symmetry, whereas single uncoupled [001 ] quantum dots have zero fine structure splitting. We found that the same double quantum dot system grown on [111 ] nanowire reveals no excitonic fine structure for all considered quantum dot distances and individual quantum dot heights. Further we demonstrate a pronounced, by several orders of magnitude, increase of the dark exciton optical activity in a quantum dot molecule as compared to a single quantum dot. For [111 ] systems we also show spontaneous localization of single particle states in one of nominally identical quantum dots forming a molecule, which is mediated by strain and origins from the lack of the vertical inversion symmetry in [111 ] nanostructures of overall C3 v symmetry. Finally, we study lowering of symmetry due to alloy randomness that triggers nonzero excitonic fine structure and the dark exciton optical activity in realistic nanowire quantum dot molecules of intermixed composition.

14 CFR 71.51 - Class C airspace.

Code of Federal Regulations, 2013 CFR

2013-01-01

... DESIGNATION OF CLASS A, B, C, D, AND E AIRSPACE AREAS; AIR TRAFFIC SERVICE ROUTES; AND REPORTING POINTS Class C Airspace § 71.51 Class C airspace. The Class C airspace areas listed in subpart C of FAA Order... 14 Aeronautics and Space 2 2013-01-01 2013-01-01 false Class C airspace. 71.51 Section 71.51...

14 CFR 71.51 - Class C airspace.

Code of Federal Regulations, 2010 CFR

2010-01-01

... DESIGNATION OF CLASS A, B, C, D, AND E AIRSPACE AREAS; AIR TRAFFIC SERVICE ROUTES; AND REPORTING POINTS Class C Airspace § 71.51 Class C airspace. The Class C airspace areas listed in subpart C of FAA Order... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Class C airspace. 71.51 Section 71.51...

Expression of fusion IL2-B7.1(IgV+C) and effects on T lymphocytes.

PubMed

Kong, Linghong; Li, Yaochen; Yang, Ye; Li, Kangsheng

2007-12-01

The search for an effective immunotherapeutic treatment for tumors is an important area of cancer research. To prepare a more effective form of the bifunctional fusion protein IL2-B7.1(IgV+C) and analyze its effect on the stimulation of T lymphocyte proliferation, we used DNAStar 5.03 software to predict the structural diversity and biochemical character of IL2-B7.1(IgV+C). We then prepared fusion protein IL2-B7.1(IgV+C) by establishing its prokaryotic expression system, and tested its effect on the stimulation of T lymphocytes in vitro. The results indicated that IL2-B7.1(IgV+C) correctly formed a secondary structure in which both IL2 and B7.1(IgV+C) maintained their original hydrophilicity and epitopes. Western blot analysis revealed that IL2-B7.1(IgV+C) was efficiently expressed. Our analysis of CTLL-2 and T-cell proliferation showed that recombinant human (rh) IL2-B7.1(IgV+C) exerted the combined stimulating effects of both rhIL2 and rh B7.1(IgV+C) on cell proliferation, and that these effects could be blocked by adding either anti-IL2 or anti-B7.1 monoclonal antibodies. A >2-fold increase in [3H]TdR incorporation compared with that of cells treated with recombinant protein IL2, or B7.1(IgV+C) alone, revealed that rhIL2-B7.1(IgV+C) had dose-dependent synergetic effects on T-cell activation in the presence of anti-CD3 monoclonal antibody. We concluded that the augmented potency of rhIL2-B7.1(IgV+C) resulted in a stronger stimulation of T-cell proliferation than either rhB7.1(IgV+C) or rhIL2 alone.

Photoacoustic contrast imaging of biological tissues with nanodiamonds fabricated for high near-infrared absorbance

PubMed Central

Zhang, Ti; Cui, Huizhong; Fang, Chia-Yi; Su, Long-Jyun; Ren, Shenqiang; Chang, Huan-Cheng; Yang, Xinmai

2013-01-01

Abstract. Radiation-damaged nanodiamonds (DNDs) are potentially ideal optical contrast agents for photoacoustic (PA) imaging in biological tissues due to their low toxicity and high optical absorbance. PA imaging contrast agents have been limited to quantum dots and gold particles, since most existing carbon-based nanoparticles, including fluorescent nanodiamonds, do not have sufficient optical absorption in the near-infrared (NIR) range. A new DND by He+ ion beam irradiation with very high NIR absorption was synthesized. These DNDs produced a 71-fold higher PA signal on a molar basis than similarly dimensioned gold nanorods, and 7.1 fmol of DNDs injected into rodents could be clearly imaged 3 mm below the skin surface with PA signal enhancement of 567% using an 820-nm laser wavelength. PMID:23400417

Synthesis of carbon-based quantum dots from starch extracts: Optical investigations.

PubMed

Al-Douri, Y; Badi, N; Voon, C H

2018-03-01

Carbon-based quantum dots (C-QDs) were synthesized through microwave-assisted carbonization of an aqueous starch suspension mediated by sulphuric and phosphoric acids. The as-prepared C-QDs showed blue, green and yellow luminescence without the addition of any surface-passivating agent. The C-QDs were further analyzed by UV-vis spectroscopy to measure the optical response of the organic compound. The energy gaps revealed narrow sizing of C-QDs in the semiconductor range. The optical refractive index and dielectric constant were investigated. The C-QDs size distribution was characterized. The results suggested an easy route to the large scale production of C-QDs materials. Copyright © 2017 John Wiley & Sons, Ltd.

Pyrite footprinting of RNA

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

Schlatterer, Joerg C., E-mail: joerg.schlatterer@einstein.yu.edu; Wieder, Matthew S.; Jones, Christopher D.

2012-08-24

Highlights: Black-Right-Pointing-Pointer RNA structure is mapped by pyrite mediated {sup {center_dot}}OH footprinting. Black-Right-Pointing-Pointer Repetitive experiments can be done in a powdered pyrite filled cartridge. Black-Right-Pointing-Pointer High {sup {center_dot}}OH reactivity of nucleotides imply dynamic role in Diels-Alderase catalysis. -- Abstract: In RNA, function follows form. Mapping the surface of RNA molecules with chemical and enzymatic probes has revealed invaluable information about structure and folding. Hydroxyl radicals ({sup {center_dot}}OH) map the surface of nucleic acids by cutting the backbone where it is accessible to solvent. Recent studies showed that a microfluidic chip containing pyrite (FeS{sub 2}) can produce sufficient {sup {center_dot}}OH tomore » footprint DNA. The 49-nt Diels-Alder RNA enzyme catalyzes the C-C bond formation between a diene and a dienophile. A crystal structure, molecular dynamics simulation and atomic mutagenesis studies suggest that nucleotides of an asymmetric bulge participate in the dynamic architecture of the ribozyme's active center. Of note is that residue U42 directly interacts with the product in the crystallized RNA/product complex. Here, we use powdered pyrite held in a commercially available cartridge to footprint the Diels-Alderase ribozyme with single nucleotide resolution. Residues C39 to U42 are more reactive to {sup {center_dot}}OH than predicted by the solvent accessibility calculated from the crystal structure suggesting that this loop is dynamic in solution. The loop's flexibility may contribute to substrate recruitment and product release. Our implementation of pyrite-mediated {sup {center_dot}}OH footprinting is a readily accessible approach to gleaning information about the architecture of small RNA molecules.« less

Development of Technologies for Early Detection and Stratification of Breast Cancer

DTIC Science & Technology

2016-12-01

heterogeneous nature of these cells. Figure 17 shows a yellow emitting Pdot (semiconducting polymer dot), which is a new family of ultra-bright fluorescent...Yu, J., Zhang, X., Sun, W., Ye, F., Wu, I., Zhang, Y., Hayden, S., Zhang, Y., Wu, C., Chiu, D.T. "New yellow fluorescent semiconducting polymer dots...fluorescent fluorinated semiconducting polymer dots for cellular imaging and analysis" Chemical Communication, 2013, 49, 8256-8258. • Zhao, M., Wei, B

Quantum dots grown in the InSb/GaSb system by liquid-phase epitaxy

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

Parkhomenko, Ya. A.; Dement’ev, P. A.; Moiseev, K. D., E-mail: mkd@iropt2.ioffe.rssi.ru

2016-07-15

The first results of the liquid-phase epitaxial growth of quantum dots in the InSb/GaSb system and atomic-force microscopy data on the structural characteristics of the quantum dots are reported. It is shown that the surface density, shape, and size of nanoislands depend on the deposition temperature and the chemical properties of the matrix surface. Arrays of InSb quantum dots on GaSb (001) substrates are produced in the temperature range T = 450–465°C. The average dimensions of the quantum dots correspond to a height of h = 3 nm and a base dimension of D = 30 nm; the surface densitymore » is 3 × 10{sup 9} cm{sup –2}.« less

Multifunctional SA-PProDOT Binder for Lithium Ion Batteries.

PubMed

Ling, Min; Qiu, Jingxia; Li, Sheng; Yan, Cheng; Kiefel, Milton J; Liu, Gao; Zhang, Shanqing

2015-07-08

An environmentally benign, highly conductive, and mechanically strong binder system can overcome the dilemma of low conductivity and insufficient mechanical stability of the electrodes to achieve high performance lithium ion batteries (LIBs) at a low cost and in a sustainable way. In this work, the naturally occurring binder sodium alginate (SA) is functionalized with 3,4-propylenedioxythiophene-2,5-dicarboxylic acid (ProDOT) via a one-step esterification reaction in a cyclohexane/dodecyl benzenesulfonic acid (DBSA)/water microemulsion system, resulting in a multifunctional polymer binder, that is, SA-PProDOT. With the synergetic effects of the functional groups (e.g., carboxyl, hydroxyl, and ester groups), the resultant SA-PProDOT polymer not only maintains the outstanding binding capabilities of sodium alginate but also enhances the mechanical integrity and lithium ion diffusion coefficient in the LiFePO4 (LFP) electrode during the operation of the batteries. Because of the conjugated network of the PProDOT and the lithium doping under the battery environment, the SA-PProDOT becomes conductive and matches the conductivity needed for LiFePO4 LIBs. Without the need of conductive additives such as carbon black, the resultant batteries have achieved the theoretical specific capacity of LiFePO4 cathode (ca. 170 mAh/g) at C/10 and ca. 120 mAh/g at 1C for more than 400 cycles.

Tuning electronic properties in graphene quantum dots by chemical functionalization: Density functional theory calculations

NASA Astrophysics Data System (ADS)

Abdelsalam, Hazem; Elhaes, Hanan; Ibrahim, Medhat A.

2018-03-01

The energy gap and dipole moment of chemically functionalized graphene quantum dots are investigated by density functional theory. The energy gap can be tuned through edge passivation by different elements or groups. Edge passivation by oxygen considerably decreases the energy gap in hexagonal nanodots. Edge states in triangular quantum dots can also be manipulated by passivation with fluorine. The dipole moment depends on: (a) shape and edge termination of the quantum dot, (b) attached group, and (c) position to which the groups are attached. Depending on the position of attached groups, the total dipole can be increased, decreased, or eliminated.

Digital SPC Switching Technology--Foreign Technology Assessment

DTIC Science & Technology

1990-12-01

India C DOT MAX C DOT DSS 0 TDX 1 Samsung , Goldstar Korea TDX 10 Daewoo, Otelco (ROK) System X Plessey/GEC U.K. (Siemens) Fetex 150 Fujitsu Japan HDX...x South Korea Alcatel ATT Malaysia Ericsson NEC New Zealand NEC Philippines DAEWOO Siemens Singapore Fujitsu (AU-, NEC Gateway Switches) Taiwan...Yes Israel Northern Telecom DMS 10 Telrad Yes OMS 100 * Malaysia Ericsson AXE Pewira Ericsson Future SDN BHD Mexico Alcatel System 12 Indetel No

Thermal wind from hot accretion flows at large radii

NASA Astrophysics Data System (ADS)

Bu, De-Fu; Yang, Xiao-Hong

2018-06-01

We study slowly rotating accretion flow at parsec and subparsec scales irradiated by low-luminosity active galactic nuclei. We take into account the Compton heating, photoionization heating by the central X-rays. The bremsstrahlung cooling, recombination, and line cooling are also included. We find that due to the Compton heating, wind can be thermally driven. The power of wind is in the range (10-6-10-3) LEdd, with LEdd being the Eddington luminosity. The mass flux of wind is in the range (0.01-1) \\dot{M}_Edd (\\dot{M}_Edd= L_Edd/0.1c^2 is the Eddington accretion rate, c is speed of light). We define the wind generation efficiency as ɛ = P_W/\\dot{M}_BHc^2, with PW being wind power, \\dot{M}_BH being the mass accretion rate on to the black hole. ɛ lies in the range 10-4-1.18. Wind production efficiency decreases with increasing mass accretion rate. The possible role of the thermally driven wind in the active galactic feedback is briefly discussed.

Zero- and two-dimensional hybrid carbon phosphors for high colorimetric purity white light-emission.

PubMed

Ding, Yamei; Chang, Qing; Xiu, Fei; Chen, Yingying; Liu, Zhengdong; Ban, Chaoyi; Cheng, Shuai; Liu, Juqing; Huang, Wei

2018-03-01

Carbon nanomaterials are promising phosphors for white light emission. A facile single-step synthesis method has been developed to prepare zero- and two-dimensional hybrid carbon phosphors for the first time. Zero-dimensional carbon dots (C-dots) emit bright blue luminescence under 365 nm UV light and two-dimensional nanoplates improve the dispersity and film forming ability of C-dots. As a proof-of-concept application, the as-prepared hybrid carbon phosphors emit bright white luminescence in the solid state, and the phosphor-coated blue LEDs exhibit high colorimetric purity white light-emission with a color coordinate of (0.3308, 0.3312), potentially enabling the successful application of white emitting phosphors in the LED field.

Small GSH-Capped CuInS2 Quantum Dots: MPA-Assisted Aqueous Phase Transfer and Bioimaging Applications.

PubMed

Zhao, Chuanzhen; Bai, Zelong; Liu, Xiangyou; Zhang, Yijia; Zou, Bingsuo; Zhong, Haizheng

2015-08-19

An efficient ligand exchange strategy for aqueous phase transfer of hydrophobic CuInS2/ZnS quantum dots was developed by employing glutathione (GSH) and mercaptopropionic acid (MPA) as the ligands. The whole process takes less than 20 min and can be scaled up to gram amount. The material characterizations show that the final aqueous soluble samples are solely capped with GSH on the surface. Importantly, these GSH-capped CuInS2/ZnS quantum dots have small size (hydrodynamic diameter <10 nm), moderate fluorescent properties (up to 34%) as well as high stability in aqueous solutions (stable for more than three months in 4 °C without any significant fluorescence quenching). Moreover, this ligand exchange strategy is also versatile for the aqueous phase transfer of other hydrophobic quantum dots, for instance, CuInSe2 and CdSe/ZnS quantum dots. We further demonstrated that GSH-capped quantum dots could be suitable fluorescence markers to penetrate cell membrane and image the cells. In addition, the GSH-capped CuInS2 quantum dots also have potential use in other fields such as photocatalysis and quantum dots sensitized solar cells.

SU-E-T-87: The Effect of Bleaching Wavelengths on the Regeneration of the Optically Stimulated Luminescence Signal of NanoDot Dosimeters Pre-Exposed to High-Doses.

PubMed

Omotayo, A; Cygler, J; Sawakuchi, G

2012-06-01

To investigate the effect of bleaching wavelengths on the regeneration of optically stimulated luminescence (OSL) signals in Al 2 O 3 :C nanoDot dosimeters pre-exposed to high doses. Regeneration is the increase in the OSL signal during storage of a bleached nanoDot that was previously pre-exposed to a high dose. This phenomenon affects the accuracy of a calibration protocol proposed by Jursinic 2010 (Med. Phys. 37:102) in which pre-exposure of nanoDots to a high-dose was used to minimize changes in the sensitivity of the detector as a function of accumulated dose. Al 2 O 3 :C OSLDs of the type nanoDot were used throughout this study. Readout was performed using the microStar reader. Bleaching of the OSLDs was performed with four 26 W fluorescent light bulbs in two modes: (i) directly under the lamps; and (ii) with the aid of a long-pass optical filter placed over the nanoDots, partially blocking wavelengths below 495 nm. Eighteen nanoDots were pre-exposed to 1 kGy dose. Then the pre-exposed nanoDots were bleached in two sets of 9 to very low residual OSL signals using bleaching modes (i) and (ii) for 12 h and 45 h, respectively. The nanoDots were then stored in dark and readout after various time intervals to monitor the regeneration of the OSL signal. We fitted the regeneration of the OSL signal using a saturation function and obtained rise-time values of 563 h and 630 h, for bleaching modes (i) and (ii), respectively. At the saturation level, the equivalent doses were about 1.18 Gy and 0.38 Gy for modes (i) and (ii), respectively. The regeneration rates of nanoDot OSLDs pre-exposed to high doses depend on the bleaching light wavelength used to reset the detectors. A bleaching source that has a low component of wavelengths below 495 nm can minimize the regeneration of the OSL signal. Natural Sciences and Engineering Research Council of Canada. © 2012 American Association of Physicists in Medicine.

CrossTalk: The Journal of Defense Software Engineering. Volume 20, Number 10, October 2007

DTIC Science & Technology

2007-10-01

ch ...Re vie w Va lua tio n Ar ch ite cti ng De ve lop m en t 1 Ar ch ite cti ng 2 Ex plo ra tio n Op er at ion 1 De ve lop m en t 2 Ar ch ite cti ng 3...engineering systems from MIT. MIT 77 Massachusetts AVE NE20-388 Cambridge, MA 02139 Phone: (617) 324-0473 Fax: (617) 258- 7845 E-mail:

Magneto-exciton transitions in laterally coupled quantum dots

NASA Astrophysics Data System (ADS)

Barticevic, Zdenka; Pacheco, Monica; Duque, Carlos A.; Oliveira, Luiz E.

2008-03-01

We present a study of the electronic and optical properties of laterally coupled quantum dots. The excitonic spectra of this system under the effects of an external magnetic field applied perpendicular to the plane of the dots is obtained, with the potential of every individual dot taken as the superposition of a quantum well potential along the axial direction with a lateral parabolic confinement potential, and the coupled two- dot system then modeled by a superposition of the potentials of each dot, with their minima at different positions and truncated at the intersection plane. The wave functions and eigenvalues are obtained in the effective-mass approximation by using an extended variational approach in which the magneto- exciton states are simultaneously obtained [1]. The allowed magneto-exciton transitions are investigated by using circularly polarized radiation in the plane perpendicular to the magnetic field. We present results on the excitonic absorption coefficient as a function of the photon energy for different geometric quantum-dot confinement and magnetic-field values. Reference: [1] Z. Barticevic, M. Pacheco, C. A. Duque and L. E. Oliveira, Phys. Rev. B 68, 073312 (2003).

Luminescent behavior of cadmium sulfide quantum dots for gallic acid estimation

NASA Astrophysics Data System (ADS)

Singh, Suman; Garg, Sourav; Chahal, Jitender; Raheja, Khushboo; Singh, Deepak; Singla, M. L.

2013-03-01

Thioglycolic acid capped cadmium sulfide (CdS/T) quantum dots have been synthesized using wet chemistry and their optical behavior has been investigated using UV-visible absorption and fluorescence spectroscopy. The role of the capping agent, sulfide source concentration, pH and temperature has been studied and discussed. Studies showed that alkaline pH leads to a decrease in the size of quantum dots and reflux temperature above 70 °C resulted in red-shift of emission spectra which is due to narrowing of the bandgap. Further, to reduce the toxicity and photochemical instability of quantum dots, the quantum dots have been functionalized with polyethylene glycol (PEG), which resulted in a 20% enhancement of the fluorescence intensity. The application potential of CdS/T-PEG quantum dots was further studied using gallic acid as a model compound. The sensing is based on fluorescence quenching of quantum dots in the presence of gallic acid, and this study showed linearity in the range from 1.3 × 10-8 to 46.5 × 10-8 mM, with a detection limit of 3.6 × 10-8 mM.

Adult Competency Education Kit. Basic Skills in Speaking, Math, and Reading for Employment. Part N. ACE Competency Based Job Descriptions: #65--Typist I; #67--Grocery Checker; #68--File Clerk; #69--Receptionist; #70--Bank Teller; #71--Clerk, General Office.

ERIC Educational Resources Information Center

San Mateo County Office of Education, Redwood City, CA. Career Preparation Centers.

This eleventh of fifteen sets of Adult Competency Education (ACE) Competency Based Job Descriptions in the ACE kit contains job descriptions for Typist I, Grocery Checker, File Clerk, Receptionist; Bank Teller; and Clerk, General Office. Each begins with a fact sheet that includes this information: occupational title, D.O.T. code, ACE number,…

Quantum Dots of InAs/GaSb Type II Superlattice for Infrared Sensing

DTIC Science & Technology

2002-01-01

QWIP )[1]. Unfortunately, fast Auger recombination rate in such interband detectors[2] and high thermal generation rate in the Electronic mail: razcghi...detectors operating at different cutoff wavelength[5]. The major noise component at zero bias is the Johnson noise , and hence the detectivity of the...which leads to a Johnson noise limited detectivity of about 3.71xl0..cm’HzŖ /W. Under reverse bias, the I/f noise will show up. However with

Characterization of c-Ki-ras and N-ras oncogenes in aflatoxin B sub 1 -induced rat liver tumors

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

McMahon, G.; Davis, E.F.; Huber, L.J.

c-Ki-ras and N-ras oncogenes have been characterized in aflatoxin B{sub 1}-induced hepatocellular carcinomas. Detection of different protooncogene and oncogene sequences and estimation of their frequency distribution were accomplished by polymerase chain reaction, cloning, and plaque screening methods. Two c-Ki-ras oncogene sequences were identified in DNA from liver tumors that contained nucleotide changes absent in DNA from livers of untreated control rats. Sequence changes involving G{center dot}C to T{center dot}A or G{center dot}C to A{center dot}T nucleotide substitutions in codon 12 were scored in three of eight tumor-bearing animals. Distributions of c-Ki-ras sequences in tumors and normal liver DNA indicated thatmore » the observed nucleotide changes were consistent with those expected to result from direct mutagenesis of the germ-line protooncogene by aflatoxin B{sub 1}. N-ras oncogene sequences were identified in DNA from two of eight tumors. Three N-ras gene regions were identified, one of which was shown to be associated with an oncogene containing a putative activating amino acid residing at codon 13. All three N-ras sequences, including the region detected in N-ras oncogenes, were present at similar frequencies in DNA samples from control livers as well as liver tumors. The presence of a potential germ-line oncogene may be related to the sensitivity of the Fischer rat strain to liver carcinogenesis by aflatoxin B{sub 1} and other chemical carcinogens.« less

75 FR 38862 - Notice and Request for Comments

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-06

...] Notice and Request for Comments AGENCY: Federal Railroad Administration, DOT. ACTION: Notice and request... comments after issuing this 60-day notice. Accordingly, DOT announces that these information collection... reconstruction of sleeping quarters (subpart C of 49 CFR part 228) must obtain approval of the Federal Railroad...

Mike O’Callaghan Federal Medical Center Campus Environmental Assessment

DTIC Science & Technology

2012-03-01

and therefore is protected under the Endangered Species Act (ESA). The western burrowing owl (Athene cunicularia) is a former USFWS C- 2 species and...JVanHavel@dot . state . nv.us> ; keiba.crear@snwa.com; LANGSTON@ClarkCountyNV. gov; ~arry . Tamashiro@ lvvwd. com <mailto : Larry . Tamashi! r o@lvvwd...Wardlaw; JVanHavel @dot .state.nv .us; keiba . c rear@snwa . com; Rodney Langston; Larry . Tamashiro@l vvwd.com; laura. j a cobsen@lvvwd . com

Ultra-broad band, low power, highly efficient coherent wavelength conversion in quantum dot SOA.

PubMed

Contestabile, G; Yoshida, Y; Maruta, A; Kitayama, K

2012-12-03

We report broadband, all-optical wavelength conversion over 100 nm span, in full S- and C-band, with positive conversion efficiency with low optical input power exploiting dual pump Four-Wave-Mixing in a Quantum Dot Semiconductor Optical Amplifier (QD-SOA). We also demonstrate by Error Vector Magnitude analysis the full transparency of the conversion scheme for coherent modulation formats (QPSK, 8-PSK, 16-QAM, OFDM-16QAM) in the whole C-band.

Image Descriptors for Displays

DTIC Science & Technology

1977-02-01

Information available for shape recognition in the dot field . What we do is to open up a nw dimension of the display, a dimension of color variation. The...line in a random location in the field of view (b); this is followed by a line mask and response choices (c). Accuracy feedback (d) follows response...dot field (c) and then gives a :4 /button response to indicate whether or not he thinks the triangle is present. Accuracy feedback (d) follows the

High-Capacitance Hybrid Supercapacitor Based on Multi-Colored Fluorescent Carbon-Dots.

PubMed

Genc, Rukan; Alas, Melis Ozge; Harputlu, Ersan; Repp, Sergej; Kremer, Nora; Castellano, Mike; Colak, Suleyman Gokhan; Ocakoglu, Kasim; Erdem, Emre

2017-09-11

Multi-colored, water soluble fluorescent carbon nanodots (C-Dots) with quantum yield changing from 4.6 to 18.3% were synthesized in multi-gram using dated cola beverage through a simple thermal synthesis method and implemented as conductive and ion donating supercapacitor component. Various properties of C-Dots, including size, crystal structure, morphology and surface properties along with their Raman and electron paramagnetic resonance spectra were analyzed and compared by means of their fluorescence and electronic properties. α-Manganese Oxide-Polypyrrole (PPy) nanorods decorated with C-Dots were further conducted as anode materials in a supercapacitor. Reduced graphene oxide was used as cathode along with the dicationic bis-imidazolium based ionic liquid in order to enhance the charge transfer and wetting capacity of electrode surfaces. For this purpose, we used octyl-bis(3-methylimidazolium)diiodide (C8H16BImI) synthesized by N-alkylation reaction as liquid ionic membrane electrolyte. Paramagnetic resonance and impedance spectroscopy have been undertaken in order to understand the origin of the performance of hybrid capacitor in more depth. In particular, we obtained high capacitance value (C = 17.3 μF/cm 2 ) which is exceptionally related not only the quality of synthesis but also the choice of electrode and electrolyte materials. Moreover, each component used in the construction of the hybrid supercapacitor is also played a key role to achieve high capacitance value.

A novel monodisperse SiO2@C-dot for the rapid and facile identification of latent fingermarks using self-quenching resistant solid-state fluorescence.

PubMed

Peng, Di; Liu, Xiang; Huang, Mengjun; Wang, Dan; Liu, Renlong

2018-04-24

Solid powder fluorescence shows great potential for application in medicine, biology, and engineering, especially in the identification of latent fingermarks in forensic science. However, conventional developing methods suffer from some drawbacks, such as low contrast, low sensitivity, low selectivity, and high toxicity. To conquer these challenges, novel SiO2@C-dot microspheres were prepared via a facile one-pot hydrothermal method by using citric acid as a carbon source and aminosilane as a nitrogen source. Interestingly, the results showed that the resultant powders possess good monodispersity, high fluorescence emission, and resistance to self-quenching. Additionally, the mechanism for the solid-state fluorescence of SiO2@C-dot compounds was also investigated. More importantly, the fingermarks on various surfaces, including transparent glasses, ceramic tiles, transparent plastics, aluminum alloys, plastic cards, painted woods, artificial leathers, and Chinese paper money, developed by the powders have indicated well-defined papillary ridges under a 365 nm UV lamp. The novel strategy of using monodisperse SiO2@C-dot microspheres as a fluorescent label for developing latent fingermarks showed greater advantages compared to conventional methods, which was also demonstrated using the automatic fingerprint identification system. It is simple, rapid, low-cost, nontoxic, and effective, and is expected to be a promising alternative for the development of latent fingerprints in forensic science.

Clinically isolated enterovirus A71 subgenogroup C4 strain with lethal pathogenicity in 14-day-old mice and the application as an EV-A71 mouse infection model.

PubMed

Xu, Yi; Ma, Shuzhi; Zhu, Limeng; Huang, Zhiqiu; Chen, Liyun; Xu, Yuhua; Yin, Haibin; Peng, Tao; Wang, Yi

2017-01-01

The Enterovirus A71 (EV-A71) subgenogroup C4 is prevalent in China. EV-A71 causes hand, foot and mouth disease (HFMD) in children and may lead to severe neurological diseases. The development of antiviral and protective vaccines against EV-A71 is significantly hindered by the lack of suitable animal models to recapitulate human neurological symptoms. In this study, GZ-CII, a highly virulent EV-A71 subgenogroup C4 strain, was isolated from hospitalized children with HFMD. Intraperitoneal infections of GZ-CII resulted in progressive neurological disease in mice as old as 14 days. Administration of an inactivated EV-A71 vaccine or an anti-EV-A71 immune serum protected the mice against the GZ-CII infection. This demonstrated that a mouse model with EV-A71 GZ-CII could be used to evaluate potential vaccine candidates and therapeutics for subgenogroup C4. Comparing the genome sequence of GZ-CII with that of the avirulent EV-A71 subgenogroup C4 strain revealed unique mutations in GZ-CII. When mutation VP2-K149I was introduced into the nonpathogenic EV-A71 subgenogroup C4 strain, the variant similar to GZ-CII significantly increased viral replication and virulence in mice. These results indicated that the VP2-K149I mutation played an important role in enhancing the virulence of the EV-A71 subgenogroup C4 strain in mice, and that mice infected with the GZ-CII strain are a promising model for evaluating vaccines and therapeutics against the EV-A71 subgenogroup C4. Copyright © 2016 Elsevier B.V. All rights reserved.

Genomic region operation kit for flexible processing of deep sequencing data.

PubMed

Ovaska, Kristian; Lyly, Lauri; Sahu, Biswajyoti; Jänne, Olli A; Hautaniemi, Sampsa

2013-01-01

Computational analysis of data produced in deep sequencing (DS) experiments is challenging due to large data volumes and requirements for flexible analysis approaches. Here, we present a mathematical formalism based on set algebra for frequently performed operations in DS data analysis to facilitate translation of biomedical research questions to language amenable for computational analysis. With the help of this formalism, we implemented the Genomic Region Operation Kit (GROK), which supports various DS-related operations such as preprocessing, filtering, file conversion, and sample comparison. GROK provides high-level interfaces for R, Python, Lua, and command line, as well as an extension C++ API. It supports major genomic file formats and allows storing custom genomic regions in efficient data structures such as red-black trees and SQL databases. To demonstrate the utility of GROK, we have characterized the roles of two major transcription factors (TFs) in prostate cancer using data from 10 DS experiments. GROK is freely available with a user guide from >http://csbi.ltdk.helsinki.fi/grok/.

Net carbon dioxide exchange rates and predicted growth patterns in Alstroemeria Jacqueline' at varying irradiances, carbon dioxide concentrations, and air temperatures

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

Leonardos, E.D.; Tsujita, M.J.; Grodzinski, B.

1994-11-01

The influence of irradiance, CO[sub 2] concentration, and air temperature on leaf and whole-plant net C exchange rate (NCER) of Alstroemeria Jacqueline' was studied. At ambient CO[sub 2], leaf net photosynthesis was maximum at irradiances above 600 [mu]mol[center dot]m[sup [minus]2][center dot]s[sup [minus]1] photosynthetically active radiation (PAR), while whole-plant NCER required 1,200 [mu]mol[center dot]m[sup [minus]2][center dot]s[sup [minus]1] PAR to be saturated. Leaf and whole-plant NCERs were doubled under CO[sub 2] enrichment of 1,500 to 2,000 [mu]l CO[sub 2]/liter. Leaf and whole-plant NCERs declined as temperature increased from 20 to 35 C. Whereas the optimum temperature range for leaf net photosynthesis wasmore » 17 to 23 C, whole-plant NCER, even at high light and high CO[sub 2], declined above 12 C. Dark respiration of leaves and whole plants increased with a Q[sub 10] of [approx] 2 at 15 to 35 C. In an analysis of day effects, irradiance, CO[sub 2] concentration, and temperature contributed 58%, 23%, and 14%, respectively, to the total variation in NCER explained by a second-order polynomial model (R[sup 2] = 0.85). Interactions among the factors accounted for 4% of the variation in day C assimilation. The potential whole-plant growth rates during varying greenhouse day and night temperature regimes were predicted for short- and long-day scenarios. The data are discussed with the view of designing experiments to test the importance of C gain in supporting flowering and high yield during routine harvest of Alstroemeria plants under commercial greenhouse conditions.« less

Influencing factors on the size uniformity of self-assembled SiGe quantum rings grown by molecular beam epitaxy.

PubMed

Cui, J; Lv, Y; Yang, X J; Fan, Y L; Zhong, Z; Jiang, Z M

2011-03-25

The size uniformity of self-assembled SiGe quantum rings, which are formed by capping SiGe quantum dots with a thin Si layer, is found to be greatly influenced by the growth temperature and the areal density of SiGe quantum dots. Higher growth temperature benefits the size uniformity of quantum dots, but results in low Ge concentration as well as asymmetric Ge distribution in the dots, which induces the subsequently formed quantum rings to be asymmetric in shape or even broken somewhere in the ridge of rings. Low growth temperature degrades the size uniformity of quantum dots, and thus that of quantum rings. A high areal density results in the expansion and coalescence of neighboring quantum dots to form a chain, rather than quantum rings. Uniform quantum rings with a size dispersion of 4.6% and an areal density of 7.8×10(8) cm(-2) are obtained at the optimized growth temperature of 640°C.

Providing Meaningful Learning for Students of the Sixth Grade of Middle School: a Study on the Moon Phases. (Breton Title: Propiciando Aprendizagem Significativa Para Alunos do Sexto Ano do Ensino Fundamental: um Estudo sobre as Fases da Lua.) Propiciando el Aprendizaje Significativo Para Alumnos del Sexto Nivel de la Educación General Básica: un Estudio sobre Las Fases de la Luna

NASA Astrophysics Data System (ADS)

Darroz, Luiz Marcelo; Samudio Pérez, Carlos Ariel; da Rosa, Cleci Werner; Heineck, Renato

2012-07-01

We relate in this article a didactic experience studying the moon phases with a group of middle school students of a private school of the municipality of Passo Fundo, RS. Based on David Ausubel's Meaningful Learning Theory, we have sought to develop a proposal following a didactic model which simulates the phases of the Moon, as based on the previous conceptions of the students. The signs of learning were evidenced by means of memory registries of the activity. From the obtained results we believe that the proposal achieved its goals, since the students were able to identify, differentiate and transfer the phenomenon of the moon phases to new contexts. Thus, it is concluded that a methodology focused on a meaningful content for the students is fundamental to the construction and genuine grasping of what is being learned. Neste artigo, relata-se uma experiência didática de estudo das fases da Lua com uma turma do 6° ano do Ensino Fundamental, de uma escola privada do município de Passo Fundo, RS. Tendo como fundamentação teórica a Teoria da Aprendizagem Significativa de David Ausubel, buscou-se desenvolver a proposta a partir de um modelo didático que simula as fases da Lua e com base nas concepções prévias dos estudantes. Os indícios da aprendizagem foram constatados através de registros de memórias da atividade. Pelos resultados apresentados, acredita-se que a proposta alcançou seus objetivos, uma vez que os estudantes conseguiram identificar, diferenciar e transferir o fenômeno das fases da Lua para novos contextos. Assim, conclui-se que uma metodologia com enfoque em um conteúdo significativo ao estudante é fundamental para a construção e compreensão genuína do que está sendo aprendido. En este artículo se relata una experiencia didáctica de estudio de las fases de la Luna con una clase de 6º año de la educación general básica de una escuela privada del municipio de Passo Fundo, RS. Teniendo como fundamentación teórica la Teoría del Aprendizaje Significativo de David Ausubel, se buscó desenvolver la propuesta a partir de un modelo didáctico que simula las Fases de la Luna, usando como base las concepciones previas de los estudiantes. Los indicios del aprendizaje fueron verificados a través de registros de memorias de la actividad. Por los resultados obtenidos creemos que la propuesta alcanzó sus objetivos, una vez que los estudiantes consiguieron identificar y transferir el fenómeno de las fases de la Luna para nuevos contextos. Así, se concluye que una metodología con enfoque en un contenido significativo para el estudiante es fundamental para la construcción y comprensión genuina de lo que está siendo aprendido.

49 CFR 40.389 - What factors may the Director consider?

Code of Federal Regulations, 2013 CFR

2013-10-01

... WORKPLACE DRUG AND ALCOHOL TESTING PROGRAMS Public Interest Exclusions § 40.389 What factors may the... duration of the noncompliance; (c) Whether there is a pattern or prior history of noncompliance; (d... DOT agency regulation, the degree to which the noncompliance affects matters common to the DOT drug...

Bridge approach slabs for Missouri DOT field evaluation of alternative and cost efficient bridge approach slabs.

DOT National Transportation Integrated Search

2013-05-01

Based on a recent study on cost efficient alternative bridge approach slab (BAS) designs (Thiagarajan et : al. 2010) has recommended three new BAS designs for possible implementation by MoDOT namely a) 20 feet cast-inplace : slab with sleeper slab (C...

Synthesis and characterization of graphene quantum dots and their size reduction using swift heavy ion beam

NASA Astrophysics Data System (ADS)

Mishra, Praveen; Bhat, Badekai Ramchandra

2018-04-01

Graphene quantum dots (GQDs) are nanosized fragments of graphene displaying quantum confinement effect. They have shown to be prepared from various methods which include ion beam etching of graphene. However, recently the modification of the GQDs has garnered tremendous attention owing to its suitability for various applications. Here, we have studied the effect of swift ion beam irradiation on the properties of GQDs. The ion beam treatment on the GQDs exhibited the change in observed photoluminescence of GQDs as they exhibited a blue luminescence on excitation with longwave UV (≈365 nm) due to the reduction in size and removal of the ethoxy (-C-O-C-) groups present on the quantum dots. This was confirmed by transmission electron microscopy, particle size analysis, and Fourier transform infrared spectroscopy.

Novel multistep BRET-FRET energy transfer using nanoconjugates of firefly proteins, quantum dots, and red fluorescent proteins

NASA Astrophysics Data System (ADS)

Alam, Rabeka; Zylstra, Joshua; Fontaine, Danielle M.; Branchini, Bruce R.; Maye, Mathew M.

2013-05-01

Sequential bioluminescence resonance energy transfer (BRET) and fluorescence resonance energy transfer (FRET) from firefly luciferase to red fluorescent proteins using quantum dot or rod acceptor/donor linkers is described. The effect of morphology and tuned optical properties on the efficiency of this unique BRET-FRET system was evaluated.Sequential bioluminescence resonance energy transfer (BRET) and fluorescence resonance energy transfer (FRET) from firefly luciferase to red fluorescent proteins using quantum dot or rod acceptor/donor linkers is described. The effect of morphology and tuned optical properties on the efficiency of this unique BRET-FRET system was evaluated. Electronic supplementary information (ESI) available: Experimental details, Fig. S1 and Table S1-S4. See DOI: 10.1039/c3nr01842c

Unveiling slim accretion disc in AGN through X-ray and Infrared observations

NASA Astrophysics Data System (ADS)

Castelló-Mor, Núria; Kaspi, Shai; Netzer, Hagai; Du, Pu; Hu, Chen; Ho, Luis C.; Bai, Jin-Ming; Bian, Wei-Hao; Yuan, Ye-Fei; Wang, Jian-Min

2017-05-01

In this work, which is a continuation of Castelló-Mor et al., we present new X-ray and infrared (IR) data for a sample of active galactic nuclei (AGN) covering a wide range in Eddington ratio over a small luminosity range. In particular, we rigorously explore the dependence of the optical-to-X-ray spectral index αOX and the IR-to-optical spectral index on the dimensionless accretion rate, \\dot{M} = \\dot{m}/η, where \\dot{m} = LAGN/LEdd and η is the mass-to-radiation conversion efficiency, in low- and high-accretion rate sources. We find that the spectral energy distribution (SED) of the faster accreting sources is surprisingly similar to those from the comparison sample of sources with lower accretion rate. In particular: (I) The optical-to-UV AGN SED of slow and fast accreting AGN can be fitted with thin accretion disc (AD) models. (II) The value of αOX is very similar in slow and fast accreting systems up to a dimensionless accretion rate \\dot{M}c ˜ 10. We only find a correlation between αOX and \\dot{M} for sources with \\dot{M} > \\dot{M}c. In such cases, the faster accreting sources appear to have systematically larger αOX values. (III) We also find that the torus in the faster accreting systems seems to be less efficient in reprocessing the primary AGN radiation having lower IR-to-optical spectral slopes. These findings, failing to recover the predicted differences between the SEDs of slim and thin ADs within the observed spectral window, suggest that additional physical processes or very special geometry act to reduce the extreme-UV radiation in fast accreting AGN. This may be related to photon trapping, strong winds and perhaps other yet unknown physical processes.

Perspective: The future of quantum dot photonic integrated circuits

NASA Astrophysics Data System (ADS)

Norman, Justin C.; Jung, Daehwan; Wan, Yating; Bowers, John E.

2018-03-01

Direct epitaxial integration of III-V materials on Si offers substantial manufacturing cost and scalability advantages over heterogeneous integration. The challenge is that epitaxial growth introduces high densities of crystalline defects that limit device performance and lifetime. Quantum dot lasers, amplifiers, modulators, and photodetectors epitaxially grown on Si are showing promise for achieving low-cost, scalable integration with silicon photonics. The unique electrical confinement properties of quantum dots provide reduced sensitivity to the crystalline defects that result from III-V/Si growth, while their unique gain dynamics show promise for improved performance and new functionalities relative to their quantum well counterparts in many devices. Clear advantages for using quantum dot active layers for lasers and amplifiers on and off Si have already been demonstrated, and results for quantum dot based photodetectors and modulators look promising. Laser performance on Si is improving rapidly with continuous-wave threshold currents below 1 mA, injection efficiencies of 87%, and output powers of 175 mW at 20 °C. 1500-h reliability tests at 35 °C showed an extrapolated mean-time-to-failure of more than ten million hours. This represents a significant stride toward efficient, scalable, and reliable III-V lasers on on-axis Si substrates for photonic integrate circuits that are fully compatible with complementary metal-oxide-semiconductor (CMOS) foundries.

Loading Cd0.5Zn0.5S Quantum Dots onto Onion-Like Carbon Nanoparticles to Boost Photocatalytic Hydrogen Generation.

PubMed

Zhou, Xiaolong; Wang, Xina; Feng, Xi; Zhang, Kun; Peng, Xiaoniu; Wang, Hanbin; Liu, Chunlei; Han, Yibo; Wang, Hao; Li, Quan

2017-07-12

Carbon dots (C dots, size < 10 nm) have been conventionally decorated onto semiconductor matrixes for photocatalytic H 2 evolution, but the efficiency is largely limited by the low loading ratio of the C dots on the photocatalyst. Here, we propose an inverse structure of Cd 0.5 Zn 0.5 S quantum dots (QDs) loaded onto the onionlike carbon (OLC) matrix for noble metal-free photocatalytic H 2 evolution. Cd 0.5 Zn 0.5 S QDs (6.9 nm) were uniformly distributed on an OLC (30 nm) matrix with both upconverted and downconverted photoluminescence property. Such an inverse structure allows the full optimization of the QD/OLC interfaces for effective energy transfer and charge separation, both of which contribute to efficient H 2 generation. An optimized H 2 generation rate of 2018 μmol/h/g (under the irradiation of visible light) and 58.6 μmol/h/g (under the irradiation of 550-900 nm light) was achieved in the Cd 0.5 Zn 0.5 S/OLC composite samples. The present work shows that using the OLC matrix in such a reverse construction is a promising strategy for noble metal-free solar hydrogen production.

Specific detection of Vibrio parahaemolyticus by fluorescence quenching immunoassay based on quantum dots.

PubMed

Wang, Ling; Zhang, Junxian; Bai, Haili; Li, Xuan; Lv, Pintian; Guo, Ailing

2014-07-01

In this study, anti-Vibrio parahaemolyticus polyclonal and monoclonal antibodies were prepared through intradermal injection immune and lymphocyte hybridoma technique respectively. CdTe quantum dots (QDs) were synthesized at pH 9.3, 98 °C for 1 h with stabilizer of 2.7:1. The fluorescence intensity was 586.499, and the yield was 62.43%. QD probes were successfully prepared under the optimized conditions of pH 7.4, 37 °C for 1 h, 250 μL of 50 mg/mL EDC · HCl, 150 μL of 4 mg/mL NHS, buffer system of Na2HPO4-citric acid, and 8 μL of 2.48 mg/mL polyclonal antibodies. As gold nanoparticles could quench fluorescence of quantum dots, the concentration of V. parahaemolyticus could be detected through measuring the reduction of fluorescence intensity in immune sandwich reaction composed of quantum dot probe, gold-labeled antibody, and the sample. For pure culture, fluorescence intensity of the system was proportional with logarithm concentration of antigen, and the correlation coefficient was 99.764%. The fluorescence quenching immunoassay based on quantum dots is established for the first time to detect Vibrio parahaemolyticus. This method may be used as rapid testing procedure due to its high simplicity and sensitivity.

Enhanced spin figure of merit in an Aharonov-Bohm ring with a double quantum dot

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

Zhou, Xingfei; Qi, Fenghua; Jin, Guojun, E-mail: gjin@nju.edu.cn

2014-04-21

We theoretically investigate the thermoelectric effects in an Aharonov-Bohm ring with a serially coupled double quantum dot embedded in one arm. An external magnetic field is perpendicularly applied to the two dots. Using the nonequilibrium Green's function method in the linear-response regime, we calculate the charge and spin figures of merit. When the energy levels of the two quantum dots are equal and the system is connected to two normal leads, a large spin figure of merit (Z{sub s}T ≈ 4.5) accompanying with a small charge figure of merit (Z{sub c}T ≈ 0) can be generated due to the remarkable bipolar effect. Further, whenmore » the system is connected to two ferromagnetic leads, the spin figure of merit can reach even a higher value about 9. Afterwards, we find that Z{sub s}T is enhanced while Z{sub c}T is reduced in the coaction of the Aharonov-Bohm flux and Rashba spin-orbit coupling. It is argued that the bipolar effect is positive (negative) to spin (charge) figure of merit in the presence of level detuning of the two quantum dots and intradot Coulomb interactions, respectively. Also, we propose a possible experiment to verify our results.« less

26 CFR 1.501(c)(7)-1 - Social clubs.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 26 Internal Revenue 7 2011-04-01 2009-04-01 true Social clubs. 1.501(c)(7)-1 Section 1.501(c)(7)-1...) INCOME TAXES (CONTINUED) Exempt Organizations § 1.501(c)(7)-1 Social clubs. (a) The exemption provided by... general, this exemption extends to social and recreation clubs which are supported solely by membership...

26 CFR 1.501(c)(7)-1 - Social clubs.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 26 Internal Revenue 7 2014-04-01 2013-04-01 true Social clubs. 1.501(c)(7)-1 Section 1.501(c)(7)-1...) INCOME TAXES (CONTINUED) Exempt Organizations § 1.501(c)(7)-1 Social clubs. (a) The exemption provided by... general, this exemption extends to social and recreation clubs which are supported solely by membership...

26 CFR 1.501(c)(7)-1 - Social clubs.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 26 Internal Revenue 7 2010-04-01 2010-04-01 true Social clubs. 1.501(c)(7)-1 Section 1.501(c)(7)-1...) INCOME TAXES (CONTINUED) Exempt Organizations § 1.501(c)(7)-1 Social clubs. (a) The exemption provided by... general, this exemption extends to social and recreation clubs which are supported solely by membership...

Anionic Gallium-Based Metal;#8722;Organic Framework and Its Sorption and Ion-Exchange Properties

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

Banerjee, Debasis; Kim, Sun Jin; Wu, Haohan

2012-04-30

A gallium-based metal-organic framework Ga{sub 6}(C{sub 9}H{sub 3}O{sub 6}){sub 8} {center_dot} (C{sub 2}H{sub 8}N){sub 6}(C{sub 3}H{sub 7}NO){sub 3}(H{sub 2}O){sub 26} [1, Ga{sub 6}(1,3,5-BTC){sub 8} {center_dot} 6DMA {center_dot} 3DMF {center_dot} 26H{sub 2}O], GaMOF-1; BTC = benzenetricarboxylate/trimesic acid and DMA = dimethylamine, with space group I{bar 4}3d, a = 19.611(1) {angstrom}, and V = 7953.4(6) {angstrom}{sup 3}, was synthesized using solvothermal techniques and characterized by synchrotron-based X-ray microcrystal diffraction. Compound 1 contains isolated gallium tetrahedra connected by the organic linker (BTC) forming a 3,4-connected anionic porous network. Disordered positively charged ions and solvent molecules are present in the pore, compensating for themore » negative charge of the framework. These positively charged molecules could be exchanged with alkali-metal ions, as is evident by an ICP-MS study. The H{sub 2} storage capacity of the parent framework is moderate with a H{sub 2} storage capacity of {approx}0.5 wt % at 77 K and 1 atm.« less

Physical and electrical characteristics of Si/SiC quantum dot superlattice solar cells with passivation layer of aluminum oxide

NASA Astrophysics Data System (ADS)

Tsai, Yi-Chia; Li, Yiming; Samukawa, Seiji

2017-12-01

In this work, we numerically simulate the silicon (Si)/silicon carbide (SiC) quantum dot superlattice solar cell (SiC-QDSL) with aluminum oxide (Al2O3-QDSL) passivation. By exploiting the passivation layer of Al2O3, the high photocurrent and the conversion efficiency can be achieved without losing the effective bandgap. Based on the two-photon transition mechanism in an AM1.5 and a one sun illumination, the simulated short-circuit current (J sc) of 4.77 mA cm-2 is very close to the experimentally measured 4.75 mA cm-2, which is higher than those of conventional SiC-QDSLs. Moreover, the efficiency fluctuation caused by the structural variation is less sensitive by using the passivation layer. A high conversion efficiency of 17.4% is thus estimated by adopting the QD’s geometry used in the experiment; and, it can be further boosted by applying a hexagonal QD formation with an inter-dot spacing of 0.3 nm.

Physical and electrical characteristics of Si/SiC quantum dot superlattice solar cells with passivation layer of aluminum oxide.

PubMed

Tsai, Yi-Chia; Li, Yiming; Samukawa, Seiji

2017-12-01

In this work, we numerically simulate the silicon (Si)/silicon carbide (SiC) quantum dot superlattice solar cell (SiC-QDSL) with aluminum oxide (Al 2 O 3 -QDSL) passivation. By exploiting the passivation layer of Al 2 O 3 , the high photocurrent and the conversion efficiency can be achieved without losing the effective bandgap. Based on the two-photon transition mechanism in an AM1.5 and a one sun illumination, the simulated short-circuit current (J sc ) of 4.77 mA cm -2 is very close to the experimentally measured 4.75 mA cm -2 , which is higher than those of conventional SiC-QDSLs. Moreover, the efficiency fluctuation caused by the structural variation is less sensitive by using the passivation layer. A high conversion efficiency of 17.4% is thus estimated by adopting the QD's geometry used in the experiment; and, it can be further boosted by applying a hexagonal QD formation with an inter-dot spacing of 0.3 nm.

High-performance cobalt carbonate hydroxide nano-dot/NiCo(CO3)(OH)2 electrode for asymmetric supercapacitors

NASA Astrophysics Data System (ADS)

Lee, Damin; Xia, Qi Xun; Yun, Je Moon; Kim, Kwang Ho

2018-03-01

Binder-free mesoporous NiCo(CO3)(OH)2 nanowire arrays were grown using a facile hydrothermal technique. The Co2(CO3)(OH)2 in NiCo(CO3)(OH)2 nanowire arrays was well-decorated as nano-dot scale (a few nanometer). In addition, increasing cobalt content in nickel compound matrix, NiCo(CO3)(OH)2 nanowire arrays were separately uniformly grown without agglomeration on Ni foam, providing a high specific surface area to help electrolyte access and ion transfer. The enticing composition and morphology of the NiCo(CO3)(OH)2 nanowire exhibit a superior specific capacity of 1288.2 mAh g-1 at a current density of 3 A g-1 and excellent cycling stability with the capacity retention of 80.7% after 10,000 cycles. Furthermore, an asymmetric supercapacitor composed of the NiCo(CO3)(OH)2 composite as a positive electrode and the graphene as a negative electrode presented a high energy density of 35.5 W h kg-1 at a power density of 2555.6 W kg-1 and satisfactory cycling stability with 71.3% capacity retention after 10,000 cycles. The great combination of the active nano-dot Co2(CO3)(OH)2 and the individually grown NiCo(CO3)(OH)2 nanowires made it a promising electrode material for asymmetric supercapacitors. A well-developed nanoarchitecture of the nano-dot Co2(CO3)(OH)2 decorated NiCo(CO3)(OH)2 composite could pave the way for an excellent electrode design for high-performance supercapacitors.

A sulphonated carbon dot-chitosan hybrid hydrogel nanocomposite as an efficient ion-exchange film for Ca2+ and Mg2+ removal

NASA Astrophysics Data System (ADS)

Baruah, Upama; Konwar, Achyut; Chowdhury, Devasish

2016-04-01

We have developed a hybrid hydrogel nanocomposite film via conjugation of oxidised carbon dots synthesized from 11-mercaptoundecanoic acid with chitosan. The potential applicability of the film was then successfully tested for the removal of Ca2+ and Mg2+ ions from solution.We have developed a hybrid hydrogel nanocomposite film via conjugation of oxidised carbon dots synthesized from 11-mercaptoundecanoic acid with chitosan. The potential applicability of the film was then successfully tested for the removal of Ca2+ and Mg2+ ions from solution. Electronic supplementary information (ESI) available: The ESI includes the detailed synthesis and characterization of carbon dots both before and after oxidation and of the carbon dot-chitosan nanocomposite films viz. DLS, SEM, UV-visible, FTIR, PL spectroscopy and TGA. See DOI: 10.1039/c6nr01129b

C8-structured carbon quantum dots: Synthesis, blue and green double luminescence, and origins of surface defects

NASA Astrophysics Data System (ADS)

Xifang, Chen; Wenxia, Zhang; Qianjin, Wang; Jiyang, Fan

Carbon quantum dots (CQDs) have attracted great attention in the past few years due to their low cytotoxicity, exploited various synthesis methods, unexampled abundance of raw materials on earth, and robust near-infrared to near-UV luminescence. Carbon nanoparticles have applications in biological labeling, delivery of drugs and biological molecules into cells, and light emitting diodes and lasing. CQDs generally exist as nanodiamonds or graphite quantum dots according to previous research reports. In this study, we report the first synthesis of the third-allotrope CQDs through carbonization of sucrose and study their luminescence properties. These CQDs have a body-centered cubic structure and each lattice point is composed of eight atoms which form a sub-cube (so called C8 crystal structure). High-resolution transmission electron microscopy and X-ray diffraction confirm the C8 structure of the synthesized carbon nanocrystallites with an average size of 2 nm. The C8 CQDs exhibit double-band luminescence with two peaks centered at around 432 and 520 nm. The study based on the photoluminescence, UV-Vis absorption, Fourier-transform infrared, and X-ray photoelectron spectroscopies reveals that the green emission originates from the C=O related surface defect.

New Introductions of Enterovirus 71 Subgenogroup C4 Strains, France, 2012

PubMed Central

Henquell, Cécile; Mirand, Audrey; Coste-Burel, Marianne; Marque-Juillet, Stéphanie; Desbois, Delphine; Lagathu, Gisèle; Bornebusch, Laure; Bailly, Jean-Luc; Lina, Bruno

2014-01-01

In France during 2012, human enterovirus 71 (EV-A71) subgenogroup C4 strains were detected in 4 children hospitalized for neonatal fever or meningitis. Phylogenetic analysis showed novel and independent EV-A71 introductions, presumably from China, and suggested circulation of C4 strains throughout France. This observation emphasizes the need for monitoring EV-A71 infections in Europe. PMID:25061698

77 FR 7230 - Agency Requests for Renewal of a Previously Approved Information Collection(s): Exemption From...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-10

... Transportation (OST), Pricing & Multilateral Affairs Division, DOT. ACTION: Notice and request for comments. SUMMARY: The Department of Transportation (DOT), OST, Pricing & Multilateral Affairs Division invites... CONTACT: John Kiser, 202-366-2435 or Bernice C. Gray, 202-366-2418, Office of the Secretary, Pricing and...

49 CFR 385.203 - What are the requirements to obtain and maintain certification?

Code of Federal Regulations, 2013 CFR

2013-10-01

... the FMCSRs and HMRs as described in detail on the FMCSA website (www.fmcsa.dot.gov). These employees...-control and periodic re-training requirements adopted by the FMCSA to ensure the maintenance of high.../qualification requirements are described in detail on the FMCSA website (www.fmcsa.dot.gov). (c) The...

49 CFR 385.203 - What are the requirements to obtain and maintain certification?

Code of Federal Regulations, 2014 CFR

2014-10-01

... the FMCSRs and HMRs as described in detail on the FMCSA website (www.fmcsa.dot.gov). These employees...-control and periodic re-training requirements adopted by the FMCSA to ensure the maintenance of high.../qualification requirements are described in detail on the FMCSA website (www.fmcsa.dot.gov). (c) The...

49 CFR 385.203 - What are the requirements to obtain and maintain certification?

Code of Federal Regulations, 2010 CFR

2010-10-01

... the FMCSRs and HMRs as described in detail on the FMCSA website (www.fmcsa.dot.gov). These employees...-control and periodic re-training requirements adopted by the FMCSA to ensure the maintenance of high.../qualification requirements are described in detail on the FMCSA website (www.fmcsa.dot.gov). (c) The...

49 CFR 385.203 - What are the requirements to obtain and maintain certification?

Code of Federal Regulations, 2012 CFR

2012-10-01

... the FMCSRs and HMRs as described in detail on the FMCSA website (www.fmcsa.dot.gov). These employees...-control and periodic re-training requirements adopted by the FMCSA to ensure the maintenance of high.../qualification requirements are described in detail on the FMCSA website (www.fmcsa.dot.gov). (c) The...

49 CFR 385.203 - What are the requirements to obtain and maintain certification?

Code of Federal Regulations, 2011 CFR

2011-10-01

... the FMCSRs and HMRs as described in detail on the FMCSA website (www.fmcsa.dot.gov). These employees...-control and periodic re-training requirements adopted by the FMCSA to ensure the maintenance of high.../qualification requirements are described in detail on the FMCSA website (www.fmcsa.dot.gov). (c) The...

Selection of a Clostridium perfringens type D epsilon toxin producer via dot-blot test.

PubMed

Gonçalves, Luciana A; Lobato, Zélia I P; Silva, Rodrigo O S; Salvarani, Felipe M; Pires, Prhiscylla S; Assis, Ronnie A; Lobato, Francisco C F

2009-11-01

Clostridium perfringens type D produces enterotoxemia, an enteric disease in ruminants, also known as pulpy kidney disease. Caused by epsilon toxin, enterotoxemia is a major exotoxin produced by this microorganism. Epsilon toxin is also the main component of vaccines against this enteric disorder. In this study, a standardized dot-blot was used to choose strains of C. perfringens type D that are producers of epsilon toxin. Clones producing epsilon toxin were chosen by limiting dilution; after three passages, lethal minimum dose titers were determined by soroneutralization test in mice. These clones produced epsilon toxin 240 times more concentrated than the original strain. The presence of the epsilon toxin gene (etx) was verified by polymerase chain reaction. All clones were positive, including those determined to be negative by dot-blot tests, suggesting that mechanisms in addition to the presence of the etx gene can influence toxin production. The dot-blot test was efficient for the selection of toxigenic colonies of C. perfringens type D and demonstrated that homogeneous populations selected from toxigenic cultures produce higher titers of epsilon toxin.

Temperature dependence of the size distribution function of InAs quantum dots on GaAs(001)

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

Arciprete, F.; Fanfoni, M.; Patella, F.

2010-04-15

We present a detailed atomic-force-microscopy study of the effect of annealing on InAs/GaAs(001) quantum dots grown by molecular-beam epitaxy. Samples were grown at a low growth rate at 500 deg. C with an InAs coverage slightly greater than critical thickness and subsequently annealed at several temperatures. We find that immediately quenched samples exhibit a bimodal size distribution with a high density of small dots (<50 nm{sup 3}) while annealing at temperatures greater than 420 deg. C leads to a unimodal size distribution. This result indicates a coarsening process governing the evolution of the island size distribution function which is limitedmore » by the attachment-detachment of the adatoms at the island boundary. At higher temperatures one cannot ascribe a single rate-determining step for coarsening because of the increased role of adatom diffusion. However, for long annealing times at 500 deg. C the island size distribution is strongly affected by In desorption.« less

Controlling circular polarization of light emitted by quantum dots using chiral photonic crystal slabs

NASA Astrophysics Data System (ADS)

Lobanov, S. V.; Tikhodeev, S. G.; Gippius, N. A.; Maksimov, A. A.; Filatov, E. V.; Tartakovskii, I. I.; Kulakovskii, V. D.; Weiss, T.; Schneider, C.; Geßler, J.; Kamp, M.; Höfling, S.

2015-11-01

We study the polarization properties of light emitted by quantum dots that are embedded in chiral photonic crystal structures made of achiral planar GaAs waveguides. A modification of the electromagnetic mode structure due to the chiral grating fabricated by partial etching of the waveguide layer has been shown to result in a high circular polarization degree ρc of the quantum dot emission in the absence of external magnetic field. The physical nature of the phenomenon can be understood in terms of the reciprocity principle taking into account the structural symmetry. At the resonance wavelength, the magnitude of | ρc| is predicted to exceed 98%. The experimentally achieved value of | ρc|=81 % is smaller, which is due to the contribution of unpolarized light scattered by grating defects, thus breaking its periodicity. The achieved polarization degree estimated removing the unpolarized nonresonant background from the emission spectra can be estimated to be as high as 96%, close to the theoretical prediction.

Solid-state thermal behavior and stability studies of theophylline-citric acid cocrystals prepared by neat cogrinding or thermal treatment

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

Hsu, Po-Chun; Lin, Hong-Liang; Wang, Shun-Li, E-mail: wangshunli@mail.ncyu.edu.tw

To investigate the thermal behavior of cocrystal formed between anhydrous theophylline (TP) and anhydrous citric acid (CA) by neat manual cogrinding or thermal treatment, DSC and FTIR microspectroscopy with curve-fitting analysis were applied. The physical mixture and 60-min ground mixture were stored at 55{+-}0.5 Degree-Sign C/40{+-}2% RH condition to determine their stability behavior. Typical TP-CA cocrystals were prepared by slow solvent evaporation method. Results indicate that the cogrinding process could gradually induce the cocrystal formation between TP and CA. The IR spectral peak shift from 3495 to 3512 cm{sup -1} and the stepwise appearance of several new IR peaks atmore » 1731, 1712, 1676, 1651, 1557 and 1265 cm{sup -1} with cogrinding time suggest that the mechanism of TP-CA cocrystal formation was evidenced by interacting TP with CA through the intermolecular O-H{center_dot}{center_dot}{center_dot}O hydrogen bonding. The stability of 60-min ground mixture of TP-CA was confirmed at 55{+-}0.5 Degree-Sign C/40{+-}2% RH condition over a storage time of 60 days. - Garphical abstract: Cogrinding, thermal and solvent-evaporation methods might easily induce the theophylline-citric acid cocrystal formation. Highlights: Black-Right-Pointing-Pointer Cogrinding process could gradually induce the cocrystal formation between TP and CA. Black-Right-Pointing-Pointer The TP-CA cocrystal was formed through the intermolecular O-H{center_dot}{center_dot}{center_dot}O hydrogen bonding. Black-Right-Pointing-Pointer The 60-min TP-CA ground mixture was similar to the solvent-evaporated cocrystal. Black-Right-Pointing-Pointer The thermal-induced TP-CA cocrystal formation was confirmed by pre-heating the physical mixture to 152 Degree-Sign C. Black-Right-Pointing-Pointer The 60-min TP-CA ground mixture was stable at accelerated condition over a storage time of 60 days.« less

Aqp5 Is a New Transcriptional Target of Dot1a and a Regulator of Aqp2

PubMed Central

Zhang, Xi; Zhou, Qiaoling; Li, Ju-Mei; Berger, Stefan; Borok, Zea; Zhou, Beiyun; Xiao, Zhou; Yin, Hongling; Liu, Mingyao; Wang, Ying; Jin, Jianping; Blackburn, Michael R.; Xia, Yang; Zhang, Wenzheng

2013-01-01

Dot1l encodes histone H3 K79 methyltransferase Dot1a. Mice with Dot1l deficiency in renal Aqp2-expressing cells (Dot1lAC) develop polyuria by unknown mechanisms. Here, we report that Aqp5 links Dot1l deletion to polyuria through Aqp2. cDNA array analysis revealed and real-time RT-qPCR validated Aqp5 as the most upregulated gene in Dot1lAC vs. control mice. Aqp5 protein is barely detectable in controls, but robustly expressed in the Dot1lAC kidneys, where it colocalizes with Aqp2. The upregulation of Aqp5 is coupled with reduced association of Dot1a and H3 dimethyl K79 with specific subregions in Aqp5 5′ flanking region in Dot1lAC vs. control mice. In vitro studies in IMCD3, MLE-15 and 293Tcells using multiple approaches including real-time RT-qPCR, luciferase reporter assay, cell surface biotinylation assay, colocalization, and co-immunoprecipitation uncovered that Dot1a represses Aqp5. Human AQP5 interacts with AQP2 and impairs its cell surface localization. The AQP5/AQP2 complex partially resides in the ER/Golgi. Consistently, AQP5 is expressed in none of 15 normal controls, but in all of 17 kidney biopsies from patients with diabetic nephropathy. In the patients with diabetic nephropathy, AQP5 colocalizes with AQP2 in the perinuclear region and AQP5 expression is associated with impaired cellular H3 dimethyl K79. Taken together, these data for the first time identify Aqp5 as a Dot1a potential transcriptional target, and an Aqp2 binding partner and regulator, and suggest that the upregulated Aqp5 may contribute to polyuria, possibly by impairing Aqp2 membrane localization, in Dot1lAC mice and in patients with diabetic nephropathy. PMID:23326416

Activation Energy of Tantalum-Tungsten Oxide Thermite Reaction

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

Cervantes, O; Kuntz, J; Gash, A

2010-02-25

The activation energy of a high melting temperature sol-gel (SG) derived tantalum-tungsten oxide thermite composite was determined using the Kissinger isoconversion method. The SG derived powder was consolidated using the High Pressure Spark Plasma Sintering (HPSPS) technique to 300 and 400 C to produce pellets with dimensions of 5 mm diameter by 1.5 mm height. A custom built ignition setup was developed to measure ignition temperatures at high heating rates (500-2000 C {center_dot} min{sup -1}). Such heating rates were required in order to ignite the thermite composite. Unlike the 400 C samples, results show that the samples consolidated to 300more » C undergo an abrupt change in temperature response prior to ignition. This change in temperature response has been attributed to the crystallization of the amorphous WO{sub 3} in the SG derived Ta-WO{sub 3} thermite composite and not to a pre-ignition reaction between the constituents. Ignition temperatures for the Ta-WO{sub 3} thermite ranged from approximately 465-670 C. The activation energy of the SG derived Ta-WO{sup 3} thermite composite consolidated to 300 and 400 C were determined to be 37.787 {+-} 1.58 kJ {center_dot} mol{sup -1} and 57.381 {+-} 2.26 kJ {center_dot} mol{sup -1}, respectively.« less

Multiphoton luminescent graphene quantum dots for in vivo tracking of human adipose-derived stem cells

NASA Astrophysics Data System (ADS)

Kim, Jin; Song, Sung Ho; Jin, Yoonhee; Park, Hyun-Ji; Yoon, Hyewon; Jeon, Seokwoo; Cho, Seung-Woo

2016-04-01

The applicability of graphene quantum dots (GQDs) for the in vitro and in vivo live imaging and tracking of different types of human stem cells is investigated. GQDs synthesized by the modified graphite intercalated compound method show efficient cellular uptake with improved biocompatibility and highly sensitive optical properties, indicating their feasibility as a bio-imaging probe for stem cell therapy.The applicability of graphene quantum dots (GQDs) for the in vitro and in vivo live imaging and tracking of different types of human stem cells is investigated. GQDs synthesized by the modified graphite intercalated compound method show efficient cellular uptake with improved biocompatibility and highly sensitive optical properties, indicating their feasibility as a bio-imaging probe for stem cell therapy. Electronic supplementary information (ESI) available: Additional results. See DOI: 10.1039/c6nr02143c

Growth of MPS-capped ZnS quantum dots in self-assembled thin films: Influence of heat treatment

NASA Astrophysics Data System (ADS)

Koç, Kenan; Tepehan, Fatma Zehra; Tepehan, Galip Gültekin

2015-12-01

The colloidal ZnS quantum dots (QDs) were prepared using 3-mercaptopropyltrimethoxysilane (MPS) molecules. Sol-gel spin coating method was used to deposit the colloidal nanoparticles on a glass substrate. Several features of the MPS were made use to produce self assembled thin films of ZnS quantum dots in a SiO2 network. Produced films were heat treated in between 225 °C and 325 °C to investigate their growth kinetics. The result showed that their size changed approximately from 3 nm to 4 nm and the first excitation peak position changed from 4.6 eV to 4.1 eV in this temperature interval. The activation energy of the nanoparticles for the Ostwald ripening process was found to be 59 kJ/mol.

Enzyme-linked immunosorbent assays for Z-DNA.

PubMed

Thomas, M J; Strobl, J S

1988-10-01

Dot blot and transblot enzyme-linked immunosorbent assays (e.l.i.s.a.) are described which provide sensitive non-radioactive methods for screening Z-DNA-specific antisera and for detecting Z-DNA in polydeoxyribonucleotides and supercoiled plasmids. In the alkaline phosphatase dot blot e.l.i.s.a., Z-DNA, Br-poly(dG-dC).poly(dG-dC), or B-DNA, poly(dG-dC).poly(dG-dC), poly(dA-dT).poly(dA-dT), Br-poly(dI-dC).poly(dI-dC), or salmon sperm DNA were spotted onto nitrocellulose discs and baked. The e.l.i.s.a. was conducted in 48-well culture dishes at 37 degrees C using a rabbit polyclonal antiserum developed against Br-poly(dG-dC).poly(dG-dC), an alkaline phosphatase-conjugated second antibody, and p-nitrophenol as the substrate. Under conditions where antibody concentrations were not limiting, alkaline phosphatase activity was linear for 2 h. Dot blot e.l.i.s.a. conditions are described which allow quantification of Z-DNA [Br-poly(dG-dC).poly(dG-dC)] within the range 5-250 ng. Dot blot and transblot horseradish peroxidase e.l.i.s.a. are described that detect Z-DNA within supercoiled plasmid DNAs immobilized on diazophenylthioether (DPT) paper. In the transblot e.l.i.s.a., plasmid pUC8 derivatives containing 16, 24, or 32 residues of Z-DNA were electrophoresed in agarose gels and electrophoretically transferred to DPT paper. Z-DNA-antibody complexes were detected by the horseradish peroxidase-catalysed conversion of 4-chloro-1-naphthol to a coloured product that was covalently bound to the DPT paper. Z-DNA antibody reactivity was specific for supercoiled Z-DNA containing plasmids after removal of the antibodies cross-reactive with B-DNA by absorption onto native DNA-cellulose. The transblot e.l.i.s.a. was sensitive enough to detect 16 base pairs of alternating G-C residues in 100 ng of pUC8 DNA.

Generic Space Science Visualization in 2D/3D using SDDAS

NASA Astrophysics Data System (ADS)

Mukherjee, J.; Murphy, Z. B.; Gonzalez, C. A.; Muller, M.; Ybarra, S.

2017-12-01

The Southwest Data Display and Analysis System (SDDAS) is a flexible multi-mission / multi-instrument software system intended to support space physics data analysis, and has been in active development for over 20 years. For the Magnetospheric Multi-Scale (MMS), Juno, Cluster, and Mars Express missions, we have modified these generic tools for visualizing data in two and three dimensions. The SDDAS software is open source and makes use of various other open source packages, including VTK and Qwt. The software offers interactive plotting as well as a Python and Lua module to modify the data before plotting. In theory, by writing a Lua or Python module to read the data, any data could be used. Currently, the software can natively read data in IDFS, CEF, CDF, FITS, SEG-Y, ASCII, and XLS formats. We have integrated the software with other Python packages such as SPICE and SpacePy. Included with the visualization software is a database application and other utilities for managing data that can retrieve data from the Cluster Active Archive and Space Physics Data Facility at Goddard, as well as other local archives. Line plots, spectrograms, geographic, volume plots, strip charts, etc. are just some of the types of plots one can generate with SDDAS. Furthermore, due to the design, output is not limited to strictly visualization as SDDAS can also be used to generate stand-alone IDL or Python visualization code.. Lastly, SDDAS has been successfully used as a backend for several web based analysis systems as well.

Study of the Spectral Properties of Nanocomposites with CdSe Quantum Dots in a Wide Range of Low Temperatures

NASA Astrophysics Data System (ADS)

Magaryan, K. A.; Eremchev, I. Y.; Karimullin, K. R.; Knyazev, M. V.; Mikhailov, M. A.; Vasilieva, I. A.; Klimusheva, G. V.

2015-09-01

Luminescence spectra of the colloidal solution of CdSe quantum dots (in toluene) were studied in a wide range of low temperatures. Samples were synthesized in the liquid crystal matrix of cadmium octanoate (CdC8). A comparative analysis of the obtained data with previous results was performed.

Customer Satisfaction: Fiscal Year 2007, Survey of Missouri Adults : Tracker Measures : 5a, 12j, 13c, 17d and 18b.

DOT National Transportation Integrated Search

2007-06-01

Using the 2006 survey as a baseline, the investigators collaborated with MoDOT to finalize the survey questions to be asked. A professional calling center was contracted to obtain a representative sample of each of the 10 MoDOT Districts, with a mini...

Development of Extinction Imagers for the Determination of Atmospheric Optical Extinction

DTIC Science & Technology

2014-08-01

system resulting from the effects of both the optics and the camera system (including the electronics). The MSI sensor includes a fiber optic taper...small dots in Fig. 7-1 are due to the fiber optic taper in the system. The brighter region near the center is due to the lens optics. To apply the...a black target wliich was a hollow black box. Clearly it would be a major advantage if we could use "targets of opportunity" from a ship, and in

Effects of lightweight outdoor clothing on the prevention of hypothermia during low-intensity exercise in the cold.

PubMed

Burtscher, Martin; Kofler, Philipp; Gatterer, Hannes; Faulhaber, Martin; Philippe, Marc; Fischer, Kathrin; Walther, Rebekka; Herten, Anne

2012-11-01

To study protective effects of windbreaker jacket and pants during exercise in the cold. Randomized pilot study. Climate chamber. Nine well-trained (V[Combining Dot Above]O2max 61.7 ± 6.6 mL/min/kg) sport students (6 male and 3 female participants). Subjects started walking for 1 hour in a climate chamber (0°C ambient temperature and wind speed of 10 km/h) at 70% V[Combining Dot Above]O2max wearing gloves, a T-shirt, and shorts. Then, the walking speed was reduced to 30% V[Combining Dot Above]O2max for an additional 60 minutes or until core temperature dropped below 35.5°C. Subsequently, 3 groups of 3 participants continued walking without change of clothing or obtaining additionally a cap and a windbreaker jacket or windbreaker jacket and pants. Core and skin temperature, thermal comfort. The main findings of this study were that exercising at 70% V[Combining Dot Above]O2max in the cold was sufficient to prevent hypothermia and that during low-intensity exercise (30% V[Combining Dot Above]O2max), the combined use of a polyester cap, lightweight windbreaker jacket, and pants was necessary to increase a prehypothermic core temperature. We strongly recommend taking a cap, windbreaker jacket, and pants for the prevention of hypothermia during exhaustive walking or running in cold weather conditions.

Technology Transition and Adoption: A Study in Search of Metrics for Evaluating Transition

DTIC Science & Technology

2010-12-01

Coalitions and Agents Project (Fast C2AP) 3 Direct Thermal to Electric Conversion (DTEC) 3 High-Frequency Active Auroral Project ( HAARP ) Instrument...which the technology is disruptive: 40 RAID TEAM SDS M&DC2 LCCMD DTEC AT3 WASP DOTS LASER Boomerang Virtual Autopsy  Program HAARP PCES Ultralog Sticky...RAID SDS Fast C2AP DTEC AT3 WASP Radar Scope DOTS SPEYES LASER Boomerang MAV ACTD HAARP TEAM PCES Ultralog Sticky Flare Active Templates LCCMD VIVID

Direct Detection of Time-Resolved Rabi Oscillationsin a Single Quantum Dot via Resonance Fluorescence

DTIC Science & Technology

2013-03-19

Ware, E. A. Stinaff, D. Gammon, M. F. Doty, A. S . Bracker, D. Gershoni, V. L. Korenev , S . C. Bădescu, Y. Lyanda-Geller, and T. L. Reinecke, Phys. Rev...A SINGLE QUANTUM DOT VIA RESONANCE FLUORESCENCE 5a. CONTRACT NUMBER FA8750-12-2-0333 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR( S ) J...NUMBER CH 7. PERFORMING ORGANIZATION NAME( S ) AND ADDRESS(ES) University of Michigan 450 Church Street Ann Arbor MI 48109-1040 8. PERFORMING

Multimodality Imaging with Silica-Based Targeted Nanoparticle Platforms

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

Jason S. Lewis

2012-04-09

Objectives: To synthesize and characterize a C-Dot silica-based nanoparticle containing 'clickable' groups for the subsequent attachment of targeting moieties (e.g., peptides) and multiple contrast agents (e.g., radionuclides with high specific activity) [1,2]. These new constructs will be tested in suitable tumor models in vitro and in vivo to ensure maintenance of target-specificity and high specific activity. Methods: Cy5 dye molecules are cross-linked to a silica precursor which is reacted to form a dye-rich core particle. This core is then encapsulated in a layer of pure silica to create the core-shell C-Dot (Figure 1) [2]. A 'click' chemistry approach has beenmore » used to functionalize the silica shell with radionuclides conferring high contrast and specific activity (e.g. 64Cu and 89Zr) and peptides for tumor targeting (e.g. cRGD and octreotate) [3]. Based on the selective Diels-Alder reaction between tetrazine and norbornene, the reaction is bioorthogonal, highyielding, rapid, and water-compatible. This radiolabeling approach has already been employed successfully with both short peptides (e.g. octreotate) and antibodies (e.g. trastuzumab) as model systems for the ultimate labeling of the nanoparticles [1]. Results: PEGylated C-Dots with a Cy5 core and labeled with tetrazine have been synthesized (d = 55 nm, zeta potential = -3 mV) reliably and reproducibly and have been shown to be stable under physiological conditions for up to 1 month. Characterization of the nanoparticles revealed that the immobilized Cy5 dye within the C-Dots exhibited fluorescence intensities over twice that of the fluorophore alone. The nanoparticles were successfully radiolabeled with Cu-64. Efforts toward the conjugation of targeting peptides (e.g. cRGD) are underway. In vitro stability, specificity, and uptake studies as well as in vivo imaging and biodistribution investigations will be presented. Conclusions: C-Dot silica-based nanoparticles offer a robust, versatile, and multi-functional platform to enhance in vivo detection sensitivity and non-invasively assay receptor expression/status of tumor cellular targets, including those of low abundance, using nuclear-NIR fluorescence imaging approaches [2]. Improvements in molecular diagnostics, refined by the availability of nanotechnology platforms, will be a key determinant in driving early-stage disease detection and prevention, ultimately leading to decreases in mortality.« less

In search of laterally heterogeneous viscosity models of Glacial Isostatic Adjustment with the ICE-6G_C global ice history model

NASA Astrophysics Data System (ADS)

Li, Tanghua; Wu, Patrick; Steffen, Holger; Wang, Hansheng

2018-05-01

Most models of Glacial Isostatic Adjustment (GIA) assume that the Earth is laterally homogeneous. However, seismic and geological observations clearly show that the Earth's mantle is laterally heterogeneous. Previous studies of GIA with lateral heterogeneity mostly focused on its effect or sensitivity on GIA predictions, and it is not clear to what extent can lateral heterogeneity solve the misfits between GIA predictions and observations. Our aim is to search for the best 3D viscosity models that can simultaneously fit the global relative sea-level (RSL) data, the peak uplift rates (u-dot from GNSS) and peak gravity-rate-of-change (g-dot from the GRACE satellite mission) in Laurentia and Fennoscandia. However, the search is dependent on the ice and viscosity model inputs - the latter depends on the background viscosity and the seismic tomography models used. In this paper, the ICE-6G_C ice model, with Bunge & Grand's seismic tomography model and background viscosity models close to VM5 will be assumed. A Coupled Laplace-Finite Element Method is used to compute gravitationally self-consistent sea level change with time dependent coastlines and rotational feedback in addition to changes in deformation, gravity and the state of stress. Several laterally heterogeneous models are found to fit the global sea level data better than laterally homogeneous models. Two of these laterally heterogeneous models also fit the ICE-6G_C peak g-dot and u-dot rates observed in Laurentia simultaneously. However, even with the introduction of lateral heterogeneity, no model that is able to fit the present-day g-dot and uplift rate data in Fennoscandia has been found. Therefore, either the ice history of ICE-6G_C in Fennoscandia and Barent Sea needs some modifications, or the sub-lithospheric property/non-thermal effect underneath northern Europe must be different from that underneath Laurentia.

Illusory displacement of equiluminous kinetic edges.

PubMed

Ramachandran, V S; Anstis, S M

1990-01-01

A stationary window was cut out of a stationary random-dot pattern. When a field of dots was moved continuously behind the window (a) the window appeared to move in the same direction even though it was stationary, (b) the position of the 'kinetic edges' defining the window was also displaced along the direction of dot motion, and (c) the edges of the window tended to fade on steady fixation even though the dots were still clearly visible. The illusory displacement was enhanced considerably if the kinetic edge was equiluminous and if the 'window' region was seen as 'figure' rather than 'ground'. Since the extraction of kinetic edges probably involves the use of direction-selective cells, the illusion may provide insights into how the visual system uses the output of these cells to localize the kinetic edges.

Carbon Nanomaterials in Biological Studies and Biomedicine.

PubMed

Teradal, Nagappa L; Jelinek, Raz

2017-09-01

The "carbon nano-world" has made over the past few decades huge contributions in diverse scientific disciplines and technological advances. While dramatic advances have been widely publicized in using carbon nanomaterials such as fullerenes, carbon nanotubes, and graphene in materials sciences, nano-electronics, and photonics, their contributions to biology and biomedicine have been noteworthy as well. This Review focuses on the use of carbon nanotubes (CNTs), graphene, and carbon quantum dots [encompassing graphene quantum dots (GQDs) and carbon dots (C-dots)] in biologically oriented materials and applications. Examples of these remarkable nanomaterials in bio-sensing, cell- and tissue-imaging, regenerative medicine, and other applications are presented and discussed, emphasizing the significance of their unique properties and their future potential. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Proving the Orbits of the Galilean Moons Through Astrophotography. (Spanish Title: Comprobando Las Órbitas de Las Lunas Galileanas a Través de la Astrofotografía.) Evidenciando as Órbitas das Luas Galileanas Atravéd da Astrofotografia

NASA Astrophysics Data System (ADS)

Iachel, Gustavo

2009-12-01

An activity related to the observation of the Galilean moons and to amateur astrophotography is presented in this work. Through the reading of excerpts of the book Sidereus Nuncius (Sidereal Messenger), by Galileo, it is possible to trace a methodology to observe the planet and its natural satellites and, with the aid of the astrophotography, to analyze the field recordings. Moreover, it is possible to compare the images obtained after plotting the relative positions of these moons to prove their orbits. This activity can be conducted by teachers, students and amateur astronomers, in order to develop their capabilities of observation of astronomical phenomena. Se presenta en este trabajo una actividad relacionada a la observación de las lunas Galileanas y a la astrofotografía amateur. A través de la lectura de tramos de la obra Sidereus Nuncius (El Mensajero Sideral) de Galileo, es posible trazar una metodología para la observación del planeta y de sus satélites naturales y, con el auxilio de la astrofotografía, analizar las anotaciones de campo. Además, es posible comparar las imágenes obtenidas con el gráfico de las posiciones relativas de estas lunas para comprobar sus órbitas. Esa actividad puede ser realizada por maestros, estudiantes y astrónomos amateurs, de forma a desarrollar sus capacidades de observación de los fenómenos astronómicos. Uma atividade relacionada à observação das luas Galileanas e à astrofotografia amadora é apresentada neste trabalho. Através da leitura de trechos da obra Sidereus Nuncius (Mensageiro Sideral), de Galileu, é possível traçar uma metodologia para a observação do planeta e de seus satélites naturais e, com o auxílio da astrofotografia, analisar as anotações de campo. Além disso, é possível comparar as imagens obtidas com o gráfico das posições relativas destas luas para evidenciar suas órbitas. Essa atividade pode ser realizada por professores, estudantes e astrônomos amadores, de forma a desenvolverem suas capacidades de observar fenômenos astronômicos.

High School Student's Alternative Conceptions About the Phenomenon of the Formation of the Moon Phases. (Spanish Title: Concepciones Alternativas de Alumnos de Educación Media Sobre el Fenómeno de Formación de las Fases de La Luna.) Concepções Alternativas de Alunos do Ensino Médio Sobre o Fenômeno de Formação das Fases da Lua

NASA Astrophysics Data System (ADS)

Iachel, Gustavo; Langhi, Rodolfo; Fernandes Scalvi, Rosa Maria

2008-07-01

Forty students, at ages between 14 and 18 years old, from three schools in Bauru city, were questioned about their alternative conceptions concerning the phenomenon of formation of the Moon Phases. It was observed that some of the pupils confound the phenomenon of the formation of the Moon Phases with the phenomenon of the formation of the lunar eclipses, others are unaware of the reason of the phenomenon, they present incoherent alternative conceptions of the reality or incomplete conceptions. The results found here are aimed at the teachers of Elementary Education and can be used as a subsidy for future development of new pedagogical methods. Cuarenta estudiantes, con edad entre 14 y 18 años, pertenecientes a tres escuelas de la ciudad de Bauru, fueron cuestionados sobre sus concepciones alternativas acerca del fenómeno de la formación de las fases de la Luna. Fue observado que algunos alumnos confunden el fenómeno de formación de las fases de la Luna con el fenómeno de formación de los eclipses lunares, otros desconocen el motivo delfenómeno, presentan concepciones alternativas incoherentes con la realidad o bien presentan concepciones incompletas. Los resultados aquí encontrados son destinados a los profesores de la Enseñanza Básica y podrán ser usados como ayuda para el futuro desarrollo de nuevos métodos pedagógicos. Quarenta estudantes, com idades entre 14 e 18 anos, pertencentes a três escolas da cidade de Bauru, foram questionados sobre suas concepções alternativas acerca do fenômeno de formação das fases da Lua. Foi observado que alguns dos alunos confundem o fenômeno da formação das fases da Lua com o fenômeno da formação dos eclipses lunares, outros desconhecem o motivo do fenômeno, apresentam concepções alternativas incoerentes com a realidade ou então concepções incompletas. Os resultados aqui encontrados são destinados aos professores do Ensino Básico e poderão ser usados como subsídio parafuturo desenvolvimento de novos métodos pedagógicos.

Development of GaN/AIN Self Assembled Quantum Dots for Room Temperature Operation of Quantum Dot Devices

DTIC Science & Technology

2003-01-01

Kramer Fabrication of hcp-Co nanocrystals via rapid pyrolysis in inverse PS - b - P2VP micelles and thermal annealing Nano Letters In Press ...the figure) and different pump photon energies. a) hν=1.684eV, b ) hν= 1.536eV and c) hν= 1.433eV. All spectra are normalized to the maximum value of...correlation functions of two consecutively emitted photons from a single excited semiconductor quantum dot. We have shown that a 6 a) b ) 0.10 [ML/s] 250 nm 3.0

Electrically pumped continuous wave quantum dot lasers epitaxially grown on patterned, on-axis (001) Si

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

Norman, Justin; Kennedy, M. J.; Selvidge, Jennifer

High performance III-V lasers at datacom and telecom wavelengths on on-axis (001) Si are needed for scalable datacenter interconnect technologies. We demonstrate electrically injected quantum dot lasers grown on on-axis (001) Si patterned with {111} v-grooves lying in the [110] direction. No additional Ge buffers or substrate miscut was used. The active region consists of five InAs/InGaAs dot-in-a-well layers. Here, we achieve continuous wave lasing with thresholds as low as 36 mA and operation up to 80°C.

Ultrafast electric phase control of a single exciton qubit

NASA Astrophysics Data System (ADS)

Widhalm, Alex; Mukherjee, Amlan; Krehs, Sebastian; Sharma, Nandlal; Kölling, Peter; Thiede, Andreas; Reuter, Dirk; Förstner, Jens; Zrenner, Artur

2018-03-01

We report on the coherent phase manipulation of quantum dot excitons by electric means. For our experiments, we use a low capacitance single quantum dot photodiode which is electrically controlled by a custom designed SiGe:C BiCMOS chip. The phase manipulation is performed and quantified in a Ramsey experiment, where ultrafast transient detuning of the exciton energy is performed synchronous to double pulse π/2 ps laser excitation. We are able to demonstrate electrically controlled phase manipulations with magnitudes up to 3π within 100 ps which is below the dephasing time of the quantum dot exciton.

Electrically pumped continuous wave quantum dot lasers epitaxially grown on patterned, on-axis (001) Si

DOE PAGES

Norman, Justin; Kennedy, M. J.; Selvidge, Jennifer; ...

2017-02-14

High performance III-V lasers at datacom and telecom wavelengths on on-axis (001) Si are needed for scalable datacenter interconnect technologies. We demonstrate electrically injected quantum dot lasers grown on on-axis (001) Si patterned with {111} v-grooves lying in the [110] direction. No additional Ge buffers or substrate miscut was used. The active region consists of five InAs/InGaAs dot-in-a-well layers. Here, we achieve continuous wave lasing with thresholds as low as 36 mA and operation up to 80°C.

Coulomb versus spin-orbit interaction in few-electron carbon-nanotube quantum dots

NASA Astrophysics Data System (ADS)

Secchi, Andrea; Rontani, Massimo

2009-07-01

Few-electron states in carbon-nanotube quantum dots are studied by means of the configuration-interaction method. The peculiar noninteracting feature of the tunneling spectrum for two electrons, recently measured by F. Kuemmeth, S. Ilani, D. C. Ralph, and P. L. McEuen [Nature (London) 452, 448 (2008)], is explained by the splitting of a low-lying isospin multiplet due to spin-orbit interaction. Nevertheless, the strongly interacting ground state forms a “Wigner molecule” made of electrons localized in space. Signatures of the electron molecule may be seen in tunneling spectra by varying the tunable dot confinement potential.

Study on the fluorescence characteristics of carbon dots.

PubMed

Mao, Xiao-Jiao; Zheng, Hu-Zhi; Long, Yi-Juan; Du, Juan; Hao, Jian-Yu; Wang, Ling-Ling; Zhou, Dong-Bo

2010-02-01

Herein, we prepared water-soluble fluorescent carbon dots with diameter about 1.5 nm from cheap commercial lampblack. These fluorescent carbon nanoparticles are stable toward photobleaching and stable in water for more than half a year without fluorescence decrease. In order to improve its fluorescence properties, we passivated these nanoparticles with bisamino-terminated polyethylene glycol (PEG(1500 N)). Therefore, both fluorescence quantum yield and lifetime increased after this progress. In addition, the passivated carbon dots were more inert to solvent than the bare one and showed different responses to pH change. Copyright (c) 2009 Elsevier B.V. All rights reserved.

Structural Characterization of the Binding of Myosin*ADP*Pi to Actin in Permeabilized Rabbit Psoas Muscle

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

Xu,S.; Gu, J.; Belknap, B.

2006-01-01

When myosin is attached to actin in a muscle cell, various structures in the filaments are formed. The two strongly bound states (A{center_dot}M{center_dot}ADP and A{center_dot}M) and the weakly bound A{center_dot}M{center_dot}ATP states are reasonably well understood. The orientation of the strongly bound myosin heads is uniform ('stereospecific' attachment), and the attached heads exhibit little spatial fluctuation. In the prehydrolysis weakly bound A{center_dot}M{center_dot}ATP state, the orientations of the attached myosin heads assume a wide range of azimuthal and axial angles, indicating considerable flexibility in the myosin head. The structure of the other weakly bound state, A{center_dot}M{center_dot}ADP{center_dot}P{sub i}, however, is poorly understood. Thismore » state is thought to be the critical pre-power-stroke state, poised to make the transition to the strongly binding, force-generating states, and hence it is of particular interest for understanding the mechanism of contraction. However, because of the low affinity between myosin and actin in the A{center_dot}M{center_dot}ADP{center_dot}P{sub i} state, the structure of this state has eluded determination both in isolated form and in muscle cells. With the knowledge recently gained in the structures of the weakly binding M{center_dot}ATP, M{center_dot}ADP{center_dot}P{sub i} states and the weakly attached A{center_dot}M{center_dot}ATP state in muscle fibers, it is now feasible to delineate the in vivo structure of the attached state of A{center_dot}M{center_dot}ADP{center_dot}P{sub i}. The series of experiments presented in this article were carried out under relaxing conditions at 25{sup o}C, where {approx}95% of the myosin heads in the skinned rabbit psoas muscle contain the hydrolysis products. The affinity for actin is enhanced by adding polyethylene glycol (PEG) or by lowering the ionic strength in the bathing solution. Solution kinetics and binding constants were determined in the presence and in the absence of PEG. When the binding between actin and myosin was increased, both the myosin layer lines and the actin layer lines increased in intensity, but the intensity profiles did not change. The configuration (mode) of attachment in the A{center_dot}M{center_dot}ADP{center_dot}P{sub i} state is thus unique among the intermediate attached states of the cross-bridge ATP hydrolysis cycle. One of the simplest explanations is that both myosin filaments and actin filaments are stabilized (e.g., undergo reduced spatial fluctuations) by the attachment. The alignment of the myosin heads in the thick filaments and the alignment of the actin monomers in the thin filaments are improved as a result. The compact atomic structure of M{center_dot}ADP{center_dot}P{sub i} with strongly coupled domains may contribute to the unique attachment configuration: the 'primed' myosin heads may function as 'transient struts' when attached to the thin filaments.« less

Biochemical characterization of recombinant Enterovirus 71 3C protease with fluorogenic model peptide substrates and development of a biochemical assay.

PubMed

Shang, Luqing; Zhang, Shumei; Yang, Xi; Sun, Jixue; Li, Linfeng; Cui, Zhengjie; He, Qiuhong; Guo, Yu; Sun, Yuna; Yin, Zheng

2015-04-01

Enterovirus 71 (EV71), a primary pathogen of hand, foot, and mouth disease (HFMD), affects primarily infants and children. Currently, there are no effective drugs against HFMD. EV71 3C protease performs multiple tasks in the viral replication, which makes it an ideal antiviral target. We synthesized a small set of fluorogenic model peptides derived from cleavage sites of EV71 polyprotein and examined their efficiencies of cleavage by EV71 3C protease. The novel peptide P08 [(2-(N-methylamino)benzoyl) (NMA)-IEALFQGPPK(DNP)FR] was determined to be the most efficiently cleaved by EV71 3C protease, with a kinetic constant kcat/Km of 11.8 ± 0.82 mM(-1) min(-1). Compared with literature reports, P08 gave significant improvement in the signal/background ratio, which makes it an attractive substrate for assay development. A Molecular dynamics simulation study elaborated the interactions between substrate P08 and EV71 3C protease. Arg39, which is located at the bottom of the S2 pocket of EV71 3C protease, may participate in the proteolysis process of substrates. With an aim to evaluate EV71 3C protease inhibitors, a reliable and robust biochemical assay with a Z' factor of 0.87 ± 0.05 was developed. A novel compound (compound 3) (50% inhibitory concentration [IC50] = 1.89 ± 0.25 μM) was discovered using this assay, which effectively suppressed the proliferation of EV 71 (strain Fuyang) in rhabdomyosarcoma (RD) cells with a highly selective index (50% effective concentration [EC50] = 4.54 ± 0.51 μM; 50% cytotoxic concentration [CC50] > 100 μM). This fast and efficient assay for lead discovery and optimization provides an ideal platform for anti-EV71 drug development targeting 3C protease. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Constructing three-dimensional porous graphene-carbon quantum dots/g-C3N4 nanosheet aerogel metal-free photocatalyst with enhanced photocatalytic activity

NASA Astrophysics Data System (ADS)

He, Huijuan; Huang, Langhuan; Zhong, Zijun; Tan, Shaozao

2018-05-01

Photocatalysis has been widely considered to be an effective way for solving the worldwide environmental pollution issues. Herein, a new type of three-dimensional (3D) ternary graphene-carbon quantum dots/g-C3N4 nanosheet (GA-CQDs/CNN) aerogel visible-light-driven photocatalyst was synthesized via a two-step hydrothermal method. In this unique ternary photocatalyst, both carbon quantum dots (CQDs) and reduced graphene oxide (rGO) could improve the visible light absorption and promote the charge separation. Furthermore, reduced graphene oxide (rGO) could act as a supportor for the 3D framework. Such a ternary system overcame the drawbacks of bulk g-C3N4 (BCN) and achieved the enhanced photocatalytic activity and long-term stability. As a result, the methyl orange (MO) removal ratio of GA-CQDs/CNN-24% was up to 91.1%, which was about 7.6 times higher than that of bulk g-C3N4 (BCN) under the identical conditions. Moreover that GA-CQDs/CNN-24% exhibited inappreciable loss of photocatalytic activity after four-cycle degradation processes. Finally, the photocatalytic mechanism of GA-CQDs/CNN-24% was interpreted both theoretically and experimentally.

Annealing effect of the InAs dot-in-well structure grown by MBE

NASA Astrophysics Data System (ADS)

Zhao, Xuyi; Wang, Peng; Cao, Chunfang; Yan, Jinyi; Zha, Fangxing; Wang, Hailong; Gong, Qian

2017-12-01

We have demonstrated that in situ annealing effect has to be taken into account in order to realize the 1.31 μm InAs quantum dot (QD) lasers with the dot-in-well (DWELL) structure. The photoluminescence (PL) properties have been investigated for the InAs DWELL samples annealed at different temperatures in situ, simulating the annealing process during the growth of the top cladding AlGaAs layer in the laser structure. The QDs with large size in the DWELL structure are vulnerable to the annealing process at temperatures above 550 °C, revealed by the drastic change in the PL spectra. However, the DWELL structure is stable during the annealing process at 540 °C for three hours. The thermal stability of the QDs in the DWELL structure has to be considered in the growth of QD lasers for long wavelength operation.

Hi-C Observations of Penumbral Bright Dots

NASA Astrophysics Data System (ADS)

Alpert, S.; Tiwari, S. K.; Moore, R. L.; Savage, S. L.; Winebarger, A. R.

2014-12-01

We use high-quality data obtained by the High Resolution Coronal Imager (Hi-C) to examine bright dots (BDs) in a sunspot's penumbra. The sizes of these BDs are on the order of 1 arcsecond (1") and are therefore hard to identify using the Atmospheric Imaging Assembly's (AIA) 0.6" pixel-1 resolution. These BDs become readily apparent with Hi-C's 0.1" pixel-1 resolution. Tian et al. (2014) found penumbral BDs in the transition region (TR) by using the Interface Region Imaging Spectrograph (IRIS). However, only a few of their dots could be associated with any enhanced brightness in AIA channels. In this work, we examine the characteristics of the penumbral BDs observed by Hi-C in a sunspot penumbra, including their sizes, lifetimes, speeds, and intensity. We also attempt to relate these BDs to the IRIS BDs. There are fewer Hi-C BDs in the penumbra than seen by IRIS, though different sunspots were studied. We use 193Å Hi-C data from July 11, 2012 which observed from ~18:52:00 UT--18:56:00 UT and supplement it with data from AIA's 193Å passband to see the complete lifetime of the dots that were born before and/or lasted longer than Hi-C's 5-minute observation period. We use additional AIA passbands and compare the light curves of the BDs at different temperatures to test whether the Hi-C BDs are TR BDs. We find that most Hi-C BDs show clear movement, and of those that do, they move in a radial direction, toward or away from the sunspot umbra. Single BDs interact with other BDs, combining to fade away or brighten. The BDs that do not interact with other BDs tend to move less. Our BDs are similar to the exceptional IRIS BDs: they move slower on average and their sizes and lifetimes are on the high end of the distribution of IRIS BDs. We infer that our penumbral BDs are some of the larger BDs observed by IRIS, those that are bright enough in TR emission to be seen in the 193Å band of Hi-C.

Effects of Exercise Induced Dehydration and Glycerol Rehydration on Anaerobic Power in Male Collegiate Wrestlers.

PubMed

McKenna, Zachary J; Gillum, Trevor L

2017-11-01

McKenna, ZJ and Gillum, TL. Effects of exercise induced dehydration and glycerol rehydration on anaerobic power in male collegiate wrestlers. J Strength Cond Res 31(11): 2965-2968, 2017-Wrestlers attempting to reach a specific weight class often use rapid weight loss (RWL). Rapid weight loss is associated with high levels of dehydration, which may hinder athletic performance. Thus, there is a need for wrestlers to optimize rehydration after achieving a specific weight. We sought to observe the effects of RWL on anaerobic power and the impact of glycerol on rehydration and power in male collegiate wrestlers (n = 7, 19.75 ± 1.67 years, 76.8 ± 4.32 kg, 11.6 ± 4.32% body fat, 59.9 ± 6.42 ml·kg·min). Subjects were assessed for body mass (BM), hydration, and mean power output (Wmean) before exercise (pre), immediately after exercise (3% dehydrated), and 60 minutes after exercise (rehydrated). Participants ran at 70% of V[Combining Dot Above]O2max in a heated room (30° C) until 3% BM loss (BML). Subjects rehydrated drinking either 26 ml·kg of water (control) or a 3% glycerol (treatment) solution containing 26 ml·kg of water and 1 g·kg of glycerol. Participants lost 3.00 ± 0.31% (control) and 2.89 ± 0.26% (treatment) of their BM from the pre- to dehydrated conditions. Wmean (control: 659.29 ± 79.12, 651.43 ± 70.71, 659.71 ± 82.78; treatment: 647.71 ± 110.64, 644.57 ± 118.15, 638.14 ± 100.71) did not differ across time (p = 0.87) nor condition (p = 0.80). In addition, glycerol had no significant impact on acute hydration (control: urine-specific gravity [SG] = 1.019 ± 0.010; treatment: SG = 1.017 ± 0.017). These data show that 3% BML did not impair anaerobic performance, and furthermore that glycerol proved ineffective for rehydration in a match like scenario for the competing wrestler.

The effect of different exercise protocols and regression-based algorithms on the assessment of the anaerobic threshold.

PubMed

Zuniga, Jorge M; Housh, Terry J; Camic, Clayton L; Bergstrom, Haley C; Schmidt, Richard J; Johnson, Glen O

2014-09-01

The purpose of this study was to examine the effect of ramp and step incremental cycle ergometer tests on the assessment of the anaerobic threshold (AT) using 3 different computerized regression-based algorithms. Thirteen healthy adults (mean age and body mass [SD] = 23.4 [3.3] years and body mass = 71.7 [11.1] kg) visited the laboratory on separate occasions. Two-way repeated measures analyses of variance with appropriate follow-up procedures were used to analyze the data. The step protocol resulted in greater mean values across algorithms than the ramp protocol for the V[Combining Dot Above]O2 (step = 1.7 [0.6] L·min and ramp = 1.5 [0.4] L·min) and heart rate (HR) (step = 133 [21] b·min and ramp = 124 [15] b·min) at the AT. There were no significant mean differences, however, in power outputs at the AT between the step (115.2 [44.3] W) and the ramp (112.2 [31.2] W) protocols. Furthermore, there were no significant mean differences for V[Combining Dot Above]O2, HR, or power output across protocols among the 3 computerized regression-based algorithms used to estimate the AT. The current findings suggested that the protocol selection, but not the regression-based algorithms can affect the assessment of the V[Combining Dot Above]O2 and HR at the AT.

Development of a high-voltage waveguide photodetector comprised of Schottky diodes and based on the Ge-Si structure with Ge quantum dots for portable thermophotovoltaic converters

NASA Astrophysics Data System (ADS)

Pakhanov, N. A.; Pchelyakov, O. P.; Yakimov, A. I.; Voitsekhovskii, A. V.

2017-03-01

This paper demontstrates the possibility of developing a high-voltage waveguide photodetector comprised of Schottky diodes and based on a Au/Ge — Si structure with Ge quantum dots pseudomorphic to a silicon matrix, which ensures an increase in the external quantum yield and open-circuit voltage. It is shown on this photodetector that there is a great increase and broadening in sensitivity up to λ = 2.1 μm, which coincides with the main radiation range of a black (gray) body at the emitter temperatures from 1200 to 1700 °C, practically used in thermophotovoltaic converters. This state of the ensemble of Ge quantum dots by means of molecular beam epitaxy can be obtained only under the condition of low growth temperature (250-300 °C). It is established that, below the Si absorption edge, photoresponse on the photodetectors under consideration is determined by two main mechanisms: absorption on the ensemble of Ge quantum dots and Fowler emission. It is shown by the analysis of the Raman scattering spectra on the optical photons of Ge-Si structures that the quantum efficiency of photodetectors based on them in the first case is due to the degree of nonuniform stress relaxation in the array of Ge quantum dots. The photoresponse directly associated with the Ge quantum dots is manifested on Schottky diodes with a superthin intermediate oxide layer SiO2, which eliminates the second mechanism. In further development, the proposed photodetector architecture with pseudomorphic Ge quantum dots can be used both for portable thermophotovoltaic converters and fiber-optic data transmission systems at wavelengths corresponding to basic telecommunication standards (λ = 0.85, 1.3 and 1.55, 1.3, and 1.55 μm) on the basis of silicon technologies.

Efficient analytical implementation of the DOT Riemann solver for the de Saint Venant-Exner morphodynamic model

NASA Astrophysics Data System (ADS)

Carraro, F.; Valiani, A.; Caleffi, V.

2018-03-01

Within the framework of the de Saint Venant equations coupled with the Exner equation for morphodynamic evolution, this work presents a new efficient implementation of the Dumbser-Osher-Toro (DOT) scheme for non-conservative problems. The DOT path-conservative scheme is a robust upwind method based on a complete Riemann solver, but it has the drawback of requiring expensive numerical computations. Indeed, to compute the non-linear time evolution in each time step, the DOT scheme requires numerical computation of the flux matrix eigenstructure (the totality of eigenvalues and eigenvectors) several times at each cell edge. In this work, an analytical and compact formulation of the eigenstructure for the de Saint Venant-Exner (dSVE) model is introduced and tested in terms of numerical efficiency and stability. Using the original DOT and PRICE-C (a very efficient FORCE-type method) as reference methods, we present a convergence analysis (error against CPU time) to study the performance of the DOT method with our new analytical implementation of eigenstructure calculations (A-DOT). In particular, the numerical performance of the three methods is tested in three test cases: a movable bed Riemann problem with analytical solution; a problem with smooth analytical solution; a test in which the water flow is characterised by subcritical and supercritical regions. For a given target error, the A-DOT method is always the most efficient choice. Finally, two experimental data sets and different transport formulae are considered to test the A-DOT model in more practical case studies.

49 CFR 32.230 - How and when must I identify workplaces?

Code of Federal Regulations, 2010 CFR

2010-10-01

... workplaces_ (1) To the DOT official that is making the award, either at the time of application or upon award...). (c) If you identified workplaces to the DOT awarding official at the time of application or award, as... 49 Transportation 1 2010-10-01 2010-10-01 false How and when must I identify workplaces? 32.230...

Exploration of the Memory Effect on the Photon-Assisted Tunneling via a Single Quantum Dot:. a Generalized Floquet Theoretical Approach

NASA Astrophysics Data System (ADS)

Chen, Hsing-Ta; Ho, Tak-San; Chu, Shih-I.

The generalized Floquet approach is developed to study memory effect on electron transport phenomena through a periodically driven single quantum dot in an electrode-multi-level dot-electrode nanoscale quantum device. The memory effect is treated using a multi-function Lorentzian spectral density (LSD) model that mimics the spectral density of each electrode in terms of multiple Lorentzian functions. For the symmetric single-function LSD model involving a single-level dot, the underlying single-particle propagator is shown to be related to a 2×2 effective time-dependent Hamiltonian that includes both the periodic external field and the electrode memory effect. By invoking the generalized Van Vleck (GVV) nearly degenerate perturbation theory, an analytical Tien-Gordon-like expression is derived for arbitrary order multi-photon resonance d.c. tunneling current. Numerically converged simulations and the GVV analytical results are in good agreement, revealing the origin of multi-photon coherent destruction of tunneling and accounting for the suppression of the staircase jumps of d.c. current due to the memory effect. Specially, a novel blockade phenomenon is observed, showing distinctive oscillations in the field-induced current in the large bias voltage limit.

A stable wavelength-tunable triggered source of single photons and cascaded photon pairs at the telecom C-band

NASA Astrophysics Data System (ADS)

Zeuner, Katharina D.; Paul, Matthias; Lettner, Thomas; Reuterskiöld Hedlund, Carl; Schweickert, Lucas; Steinhauer, Stephan; Yang, Lily; Zichi, Julien; Hammar, Mattias; Jöns, Klaus D.; Zwiller, Val

2018-04-01

The implementation of fiber-based long-range quantum communication requires tunable sources of single photons at the telecom C-band. Stable and easy-to-implement wavelength-tunability of individual sources is crucial to (i) bring remote sources into resonance, (ii) define a wavelength standard, and (iii) ensure scalability to operate a quantum repeater. So far, the most promising sources for true, telecom single photons are semiconductor quantum dots, due to their ability to deterministically and reliably emit single and entangled photons. However, the required wavelength-tunability is hard to attain. Here, we show a stable wavelength-tunable quantum light source by integrating strain-released InAs quantum dots on piezoelectric substrates. We present triggered single-photon emission at 1.55 μm with a multi-photon emission probability as low as 0.097, as well as photon pair emission from the radiative biexciton-exciton cascade. We achieve a tuning range of 0.25 nm which will allow us to spectrally overlap remote quantum dots or tuning distant quantum dots into resonance with quantum memories. This opens up realistic avenues for the implementation of photonic quantum information processing applications at telecom wavelengths.

The Validity and Contributing Physiological Factors to 30-15 Intermittent Fitness Test Performance in Rugby League.

PubMed

Scott, Tannath J; Duthie, Grant M; Delaney, Jace A; Sanctuary, Colin E; Ballard, David A; Hickmans, Jeremy A; Dascombe, Ben J

2017-09-01

Scott, TJ, Duthie, GM, Delaney, JA, Sanctuary, CE, Ballard, DA, Hickmans, JA, and Dascombe, BJ. The validity and contributing physiological factors to 30-15 intermittent fitness test performance in rugby league. J Strength Cond Res 31(9): 2409-2416, 2017-This study examined the validity of the 30-15 Intermittent Fitness Test (30-15IFT) within rugby league. Sixty-three Australian elite and junior-elite rugby league players (22.5 ± 4.5 years, 96.1 ± 9.5 kg, Σ7 skinfolds: 71.0 ± 18.7 mm) from a professional club participated in this study. Players were assessed for anthropometry (body mass, Σ7 skinfolds, lean mass index), prolonged high-intensity intermittent running (PHIR; measured by 30-15IFT), predicted aerobic capacity (MSFT) and power (AAS), speed (40 m sprint), repeated sprint, and change of direction (COD-505 agility test) ability before and after an 11-week preseason training period. Validity of the 30-15IFT was established using Pearson's coefficient correlations. Forward stepwise regression model identified the fewest variables that could predict individual final velocity (VIFT) and change within 30-15IFT performance. Significant correlations between VIFT and Σ7 skinfolds, repeated sprint decrement, V[Combining Dot Above]O2maxMSFT, and average aerobic speed were observed. A total of 71.8% of the adjusted variance in 30-15IFT performance was explained using a 4-step best fit model (V[Combining Dot Above]O2maxMSFT, 61.4%; average aerobic speed, 4.7%; maximal velocity, 4.1%; lean mass index, 1.6%). Across the training period, 25% of the variance was accounted by ΔV[Combining Dot Above]O2maxMSFT (R = 0.25). These relationships suggest that the 30-15IFT is a valid test of PHIR within rugby league. Poor correlations were observed with measures of acceleration, speed, and COD. These findings demonstrate that although the 30-15IFT is a valid measure of PHIR, it also simultaneously examines various physiological capacities that differ between sporting cohorts.

Molecular basis of the fructose-2,6-bisphosphatase reaction of PFKFB3: Transition state and the C-terminal function

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

Cavalier, Michael C.; Kim, Song-Gun; Neau, David

2012-03-22

The molecular basis of fructose-2,6-bisphosphatase (F-2,6-P{sub 2}ase) of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase (PFKFB) was investigated using the crystal structures of the human inducible form (PFKFB3) in a phospho-enzyme intermediate state (PFKFB3-P {center_dot} F-6-P), in a transition state-analogous complex (PFKFB3 {center_dot} AlF{sub 4}), and in a complex with pyrophosphate (PFKFB3 {center_dot} PP{sub i}) at resolutions of 2.45, 2.2, and 2.3 {angstrom}, respectively. Trapping the PFKFB3-P {center_dot} F-6-P intermediate was achieved by flash cooling the crystal during the reaction, and the PFKFB3 {center_dot} AlF{sub 4} and PFKFB3 {center_dot} PP{sub i} complexes were obtained by soaking. The PFKFB3 {center_dot} AlF{sub 4} and PFKFB3 {center_dot} PP{sub i}more » complexes resulted in removing F-6-P from the catalytic pocket. With these structures, the structures of the Michaelis complex and the transition state were extrapolated. For both the PFKFB3-P formation and break down, the phosphoryl donor and the acceptor are located within {approx}5.1 {angstrom}, and the pivotal point 2-P is on the same line, suggesting an 'in-line' transfer with a direct inversion of phosphate configuration. The geometry suggests that NE2 of His253 undergoes a nucleophilic attack to form a covalent N-P bond, breaking the 2O-P bond in the substrate. The resulting high reactivity of the leaving group, 2O of F-6-P, is neutralized by a proton donated by Glu322. Negative charges on the equatorial oxygen of the transient bipyramidal phosphorane formed during the transfer are stabilized by Arg252, His387, and Asn259. The C-terminal domain (residues 440-446) was rearranged in PFKFB3 {center_dot} PP{sub i}, implying that this domain plays a critical role in binding of substrate to and release of product from the F-2,6-P{sub 2}ase catalytic pocket. These findings provide a new insight into the understanding of the phosphoryl transfer reaction.« less

Oxygen uptake and local Po2 profiles in submerged larvae of phaeoxantha klugii (Coleoptera: Cicindelidae), as well as their metabolic rate in air.

PubMed

Zerm, M; Zinkler, D; Adis, J

2004-01-01

We studied whether oxygen uptake from the surrounding water might enhance survival in submerged third instar larvae of Phaeoxantha klugii, a tiger beetle from the central Amazonian floodplains. Local oxygen partial pressures (Po(2)) were measured with microcoaxial needle electrodes close to larvae submerged in initially air-saturated still water. The Po(2) profiles showed that the larvae exploit oxygen from the aquatic medium. Metabolism in the air of more or less resting larvae was determined by measuring the rate of CO(2) production (sV dot co2) with an infrared gas analyzer at 29 degrees C. The sV dot co2 was around 1.8 mu L g(-1) min(-1), equivalent to an oxygen consumption rate (sV dot o2) of 1.8-2.6 mu L g(-1) min(-1). Oxygen consumption (V dot o2) of individually submerged larvae measured in closed respiration chambers at 19-10.3 kPa Po(2) (initially air saturated, 29 degrees C) ranged between 0.05 and 0.2 mu L min(-1) and was not correlated with body mass. The sV dot o2 ranged between 0.1 and 0.4 mu L min(-1), that is, 4%-22% of the metabolic rate measured in air. Mean V dot o2 decreased with declining Po(2); however, some individuals showed contrary patterns. V dot o2 was additionally measured in dormant larvae, in larvae submerged for 1-2 d in open water or for 30-49 d within sediment, as well as in larvae exposed to anoxia before the measurements. The range of V dot o2 was similar in all groups, indicating that the larvae exploit oxygen from the water whenever available. Similar V dot o2 across the whole range of body mass investigated (0.31-0.76 g) suggests that oxygen uptake occurs by spiracular uptake. Assuming that larvae survive for some time at rates comparable to depressed metabolic rates reported for other insect species, it can be concluded that oxygen uptake from water can sustain aerobic metabolism even under quite severe hypoxia. It might therefore play an important role for survival during inundation periods.

Competitive fragmentation pathways of acetic acid dimer explored by synchrotron VUV photoionization mass spectrometry and electronic structure calculations

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

Guan Jiwen; Hu Yongjun; Zou Hao

2012-09-28

In present study, photoionization and dissociation of acetic acid dimers have been studied with the synchrotron vacuum ultraviolet photoionization mass spectrometry and theoretical calculations. Besides the intense signal corresponding to protonated cluster ions (CH{sub 3}COOH){sub n}{center_dot}H{sup +}, the feature related to the fragment ions (CH{sub 3}COOH)H{sup +}{center_dot}COO (105 amu) via {beta}-carbon-carbon bond cleavage is observed. By scanning photoionization efficiency spectra, appearance energies of the fragments (CH{sub 3}COOH){center_dot}H{sup +} and (CH{sub 3}COOH)H{sup +}{center_dot}COO are obtained. With the aid of theoretical calculations, seven fragmentation channels of acetic acid dimer cations were discussed, where five cation isomers of acetic acid dimer are involved.more » While four of them are found to generate the protonated species, only one of them can dissociate into a C-C bond cleavage product (CH{sub 3}COOH)H{sup +}{center_dot}COO. After surmounting the methyl hydrogen-transfer barrier 10.84 {+-} 0.05 eV, the opening of dissociative channel to produce ions (CH{sub 3}COOH){sup +} becomes the most competitive path. When photon energy increases to 12.4 eV, we also found dimer cations can be fragmented and generate new cations (CH{sub 3}COOH){center_dot}CH{sub 3}CO{sup +}. Kinetics, thermodynamics, and entropy factors for these competitive dissociation pathways are discussed. The present report provides a clear picture of the photoionization and dissociation processes of the acetic acid dimer in the range of the photon energy 9-15 eV.« less

Impact of second-order piezoelectricity on electronic and optical properties of c-plane InxGa1-xN quantum dots: Consequences for long wavelength emitters

NASA Astrophysics Data System (ADS)

Patra, Saroj Kanta; Schulz, Stefan

2017-09-01

In this work, we present a detailed analysis of the second-order piezoelectric effect in c-plane InxGa1-xN/GaN quantum dots and its consequences for electronic and optical properties of these systems. Special attention is paid to the impact of increasing In content x on the results. We find that in general the second-order piezoelectric effect leads to an increase in the electrostatic built-in field. Furthermore, our results show that for an In content ≥30%, this increase in the built-in field has a significant effect on the emission wavelength and the radiative lifetimes. For instance, at 40% In, the radiative lifetime is more than doubled when taking second-order piezoelectricity into account. Overall, our calculations reveal that when designing and describing the electronic and optical properties of c-plane InxGa1-xN/GaN quantum dot based light emitters with high In contents, second-order piezoelectric effects cannot be neglected.

Raman scattering and X-ray powder diffraction studies of hydrate layered perovskites: dirubidium aquapentafluoromanganate(III) and dipotassium aquapentafluoroferrate(III)

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

Galicka, Karolina; Slodczyk, Aneta; Ratuszna, Alicja

2004-06-08

The structural and vibrational properties of above mentioned crystals were determined using X-ray powder diffraction and Raman scattering experiments. At room temperature hydrate layered perovskites: Rb{sub 2}MnF{sub 5}{center_dot}H{sub 2}O and K{sub 2}FeF{sub 5}{center_dot}H{sub 2}O exhibit orthorhombic--Cmcm (D{sub 2h}{sup 17}) and monoclinic--C2/c (C{sub 2h}{sup 6}) symmetry. Their structure is built up of MnF{sub 6} or FeF{sub 5}{center_dot}H{sub 2}O octahedra forming trans-linked zig-zag chains or hydrogen bonded zig-zag chains along the major crystallographic direction [0 0 1], respectively. To confirm crystal structures and to describe lattice dynamics of these compounds the vibrational normal modes (in {gamma} point of first Brillouin zone) weremore » calculated on the base of the group theory analysis and compared with the spectra obtained from Raman scattering experiments. A relatively good reliability was obtained for both X-ray powder diffraction and Raman scattering.« less

Effects of air annealing on CdS quantum dots thin film grown at room temperature by CBD technique intended for photosensor applications

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

Shaikh, Shaheed U.; Desale, Dipalee J.; Siddiqui, Farha Y.

2012-11-15

Graphical abstract: The effect of different intensities (40, 60 100 and 200 W) of light on CdS quantum dots thin film annealed at 350 °C indicating enhancement in (a) photo-current and (b) photosensitivity. Highlights: ► The preparation of CdS nanodot thin film at room temperature by M-CBD technique. ► Study of air annealing on prepared CdS nanodots thin film. ► The optimized annealing temperature for CdS nanodot thin film is 350 °C. ► Modified CdS thin films can be used in photosensor application. -- Abstract: CdS quantum dots thin-films have been deposited onto the glass substrate at room temperature usingmore » modified chemical bath deposition technique. The prepared thin films were further annealed in air atmosphere at 150, 250 and 350 °C for 1 h and subsequently characterized by scanning electron microscopy, ultraviolet–visible spectroscopy, electrical resistivity and I–V system. The modifications observed in morphology and opto-electrical properties of the thin films are presented.« less

Dosimetric characterization of a new directional low-dose rate brachytherapy source.

PubMed

Aima, Manik; DeWerd, Larry A; Mitch, Michael G; Hammer, Clifford G; Culberson, Wesley S

2018-05-24

CivaTech Oncology Inc. (Durham, NC) has developed a novel low-dose rate (LDR) brachytherapy source called the CivaSheet. TM The source is a planar array of discrete elements ("CivaDots") which are directional in nature. The CivaDot geometry and design are considerably different than conventional LDR cylindrically symmetric sources. Thus, a thorough investigation is required to ascertain the dosimetric characteristics of the source. This work investigates the repeatability and reproducibility of a primary source strength standard for the CivaDot and characterizes the CivaDot dose distribution by performing in-phantom measurements and Monte Carlo (MC) simulations. Existing dosimetric formalisms were adapted to accommodate a directional source, and other distinguishing characteristics including the presence of gold shield x-ray fluorescence were addressed in this investigation. Primary air-kerma strength (S K ) measurements of the CivaDots were performed using two free-air chambers namely, the Variable-Aperture Free-Air Chamber (VAFAC) at the University of Wisconsin Medical Radiation Research Center (UWMRRC) and the National Institute of Standards and Technology (NIST) Wide-Angle Free-Air Chamber (WAFAC). An intercomparison of the two free-air chamber measurements was performed along with a comparison of the different assumed CivaDot energy spectra and associated correction factors. Dose distribution measurements of the source were performed in a custom polymethylmethacrylate (PMMA) phantom using Gafchromic TM EBT3 film and thermoluminescent dosimeter (TLD) microcubes. Monte Carlo simulations of the source and the measurement setup were performed using MCNP6 radiation transport code. The CivaDot S K was determined using the two free-air chambers for eight sources with an agreement of better than 1.1% for all sources. The NIST measured CivaDot energy spectrum intensity peaks were within 1.8% of the MC-predicted spectrum intensity peaks. The difference in the net source-specific correction factor determined for the CivaDot free-air chamber measurements for the NIST WAFAC and UW VAFAC was 0.7%. The dose-rate constant analog was determined to be 0.555 cGy h -1 U -1 . The average difference observed in the estimated CivaDot dose-rate constant analog using measurements and MCNP6-predicted value (0.558 cGy h -1 U -1 ) was 0.6% ± 2.3% for eight CivaDot sources using EBT3 film, and -2.6% ± 1.7% using TLD microcube measurements. The CivaDot two-dimensional dose-to-water distribution measured in phantom was compared to the corresponding MC predictions at six depths. The observed difference using a pixel-by-pixel subtraction map of the measured and the predicted dose-to-water distribution was generally within 2-3%, with maximum differences up to 5% of the dose prescribed at the depth of 1 cm. Primary S K measurements of the CivaDot demonstrated good repeatability and reproducibility of the free-air chamber measurements. Measurements of the CivaDot dose distribution using the EBT3 film stack phantom and its subsequent comparison to Monte Carlo-predicted dose distributions were encouraging, given the overall uncertainties. This work will aid in the eventual realization of a clinically viable dosimetric framework for the CivaSheet based on the CivaDot dose distribution. © 2018 American Association of Physicists in Medicine.

Hi-C Observations of Penumbral Bright Dots

NASA Technical Reports Server (NTRS)

Alpert, S. E.; Tiwari, S. K.; Moore, R. L.; Savage, S. L.; Winebarger, A. R.

2014-01-01

We use high-quality data obtained by the High Resolution Coronal Imager (Hi-C) to examine bright dots (BDs) in a sunspot's penumbra. The sizes of these BDs are on the order of 1 arcsecond (1") and are therefore hard to identify using the Atmospheric Imaging Assembly's (AIA) 0.6" pixel(exp -1) resolution. These BD become readily apparent with Hi-C's 0.1" pixel(exp -1) resolution. Tian et al. (2014) found penumbral BDs in the transition region (TR) by using the Interface Region Imaging Spectrograph (IRIS). However, only a few of their dots could be associated with any enhanced brightness in AIA channels. In this work, we examine the characteristics of the penumbral BDs observed by Hi-C in a sunspot penumbra, including their sizes, lifetimes, speeds, and intensity. We also attempt to find any association of these BDs to the IRIS BDs. There are fewer Hi-C BDs in the penumbra than seen by IRIS, though different sunspots were studied. We use 193 Angstroms Hi-C data from July 11, 2012 which observed from approximately 18:52:00 UT- 18:56:00 UT and supplement it with data from AIA's 193 Angstrom passband to see the complete lifetime of the dots that were born before and/or lasted longer than Hi- C's 5-minute observation period. We use additional AIA passbands and compare the light curves of the BDs at different temperatures to test whether the Hi-C BDs are TR BDs. We find that most Hi-C BDs show clear movement, and of those that do, they move in a radial direction, toward or away from the sunspot umbra. Single BDs interact with other BDs, combining to fade away or brighten. The BDs that do not interact with other BDs tend to move less. Many of the properties of our BDs are similar to the extreme values of the IRIS BDs, e.g., they move slower on average and their sizes and lifetimes are on the higher end of the IRIS BDs. We infer that our penumbral BDs are the large-scale end of the distribution of BDs observed by IRIS.

Camp Laguardia, Korea. Limited Surface Observations Climatic Summary (LISOCS). Parts A-F.

DTIC Science & Technology

1988-03-01

OBSERVATIONS" CLIMATIC SUMMARY "LISOCS" CAMP LAGUARDIA KOREA MSC #471060 N 37 44 E 127 03 ELEV 174 FT PKSB PARTS A - F HOURS SUMMARIZED: 0600 - 1800 PERIOD OF...8217.p " .? TOAL C 4 ." TV.’ 0.5 1._ 2. I CTAL N Um’ L’ OF 0 ’ SF ATI ONS ,7 lp i: r L 06 L UC l’±11LOGY YPRtNCH PLPLFA-lbrE FRECUENCY OF OCCUQRCNCE OF...7 uC 1606 25.7 68.3 72 .C 71.b 70.6 72.6 73.9 72.9 7,.9 7’.9 70.9 73.9 7).9 72.9 70.9 GE 14% ’I t5.9 685 %_ 737 7C.7 73.7 71.1 71.1 7.1 71.1 71.1 71.1

Enhanced photoluminescence of multilayer Ge quantum dots on Si(001) substrates by increased overgrowth temperature.

PubMed

Liu, Zhi; Cheng, Buwen; Hu, Weixuan; Su, Shaojian; Li, Chuanbo; Wang, Qiming

2012-07-11

Four-bilayer Ge quantum dots (QDs) with Si spacers were grown on Si(001) substrates by ultrahigh vacuum chemical vapor deposition. In three samples, all Ge QDs were grown at 520 °C, while Si spacers were grown at various temperatures (520 °C, 550 °C, and 580 °C). Enhancement and redshift of room temperature photoluminescence (PL) were observed from the samples in which Si spacers were grown at a higher temperature. The enhancement of PL is explained by higher effective electrons capturing in the larger size Ge QDs. Quantum confinement of the Ge QDs is responsible for the redshift of PL spectra. The Ge QDs' size and content were investigated by atomic force microscopy and Raman scattering measurements.

CONUS (Continental United States) Omega/VLF Data Collection: Flight Test.

DTIC Science & Technology

1983-12-01

ET AL. DEC 83 UNCLASSIFIED DOT/ FR /P-83/35 DOT-FRI-S-C-i80 F/G 17/7 ? mEEEEEEEEEoiE mEEEEEmongooEE EEEEEEEEEEmhEE EhhhEEEEEEEEEE EEEEEEEEEomhhEE...Florida 33406 M T p fR p r e ei dC w 12. Sp..-.; e Hom e and Address FI A R..EPOR Department of Transportation Federal Aviation Administration 1 . 800...PDocssory Unit .413 9.MIIIU L . .N-iply et rRgt M IFISI/WL E IIE WTWAT/o) Eastor ost or e bankd dgendnt ponthe llos fr atmatc squetialselctin o 1 F

Electron and Nuclear Spin Interactions in the Optical Spectra of Single GaAs Quantum Dots

DTIC Science & Technology

2001-05-28

VOLUME 86, NUMBER 22 P H Y S I C A L R E V I E W L E T T E R S 28 MAY 2001 5 Electron and Nuclear Spin Interactions in the Optical Spectra of Single...GaAs Quantum Dots D. Gammon, Al. L. Efros, T. A. Kennedy, M. Rosen, D. S . Katzer, and D. Park Naval Research Laboratory, Washington, D.C. 20375 S . W...Brown NIST, Gaithersburg, Maryland V. L. Korenev and I. A. Merkulov A. F. Ioffe Institute, St. Petersburg, Russia (Received 18 December 2000) Fine and

Electrically Tunable g Factors in Quantum Dot Molecular Spin States

DTIC Science & Technology

2006-11-10

Electrically Tunable g Factors in Quantum Dot Molecular Spin States M. F. Doty,1,* M. Scheibner,1 I. V. Ponomarev,1 E. A. Stinaff,1 A. S . Bracker,1 V...L. Korenev ,2 T. L. Reinecke,1 and D. Gammon1 1Naval Research Laboratory, Washington, D.C. 20375, USA 2A.F. Ioffe Physical Technical Institute, St...on the applied electric field (F). PRL 97, 197202 (2006) P H Y S I C A L R E V I E W L E T T E R S week ending 10 NOVEMBER 2006 0031-9007=06=97(19

Meson production in relativistic heavy-ion collisions at AGS energies

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

Steadman, S.G.; E802 Collaboration

1993-07-01

Single particle inclusive spectra are presented for pion and kaon production in Si+Au reactions at an incident momentum of 14.6 A {center_dot} GeV/c and Au+Au reactions at an incident momentum of 11.6 A {center_dot} GeV/c. A simple geometric scaling of the pion production for central collisions as A{sub proj}{sup 1/3} and A{sub targ}{sup 2/3} results from the observed production of about one pion per participant. Kaon yields are shown to be proportional to the number of excited participants and consistent with RQMD and ARC calculations.

Meson production in relativistic heavy-ion collisions at AGS energies

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

Steadman, S.G.

1993-01-01

Single particle inclusive spectra are presented for pion and kaon production in Si + Au reactions at an incident momentum of 14.6 A [center dot] GeV/c and Au + Au reactions at an incident momentum of 11.6 A [center dot] GeV/c. A simple geometric scaling of the pion production for central collisions as A[sub proj][sup 1/3] and A[sub targ][sup 2/3] results from the observed production of about one pion per participant. Kaon yields are shown to be proportional to the number of excited participants and consistent with RQMD and ARC calculations.

The effects of combined application of inorganic Martian dust simulant and carbon dots on glutamate transport rat brain nerve terminals

NASA Astrophysics Data System (ADS)

Borisova, Tatiana; Krisanova, Natalia; Nazarova, Anastasiya; Borysov, Arseniy; Pastukhov, Artem; Pozdnyakova, Natalia; Dudarenko, Marina

2016-07-01

During inhalation, nano-/microsized particles are efficiently deposited in nasal, tracheobronchial, and alveolar regions and can be transported to the central nervous system (Oberdorster et al., 2004). Recently, the research team of this study found the minor fractions of nanoparticles with the size ~ 50 -60 nm in Lunar and Martian dust stimulants (JSC-1a and JSC, ORBITEC Orbital Technologies Corporation, Madison, Wisconsin), whereas the average size of the simulants was 1 mm and 4mm, respectively (Krisanova et al., 2013). Also, the research team of this study discovered new phenomenon - the neuromodulating and neurotoxic effect of carbon nano-sized particles - Carbon dots (C-dots), originated from ash of burned carbon-containing product (Borisova et al, 2015). The aims of this study was to analyse acute effects of upgraded stimulant of inorganic Martian dust derived from volcanic ash (JSC-1a/JSC, ORBITEC Orbital Technologies Corporation, Madison, Wisconsin) by the addition of carbon components, that is, carbon dots, on the key characteristic of synaptic neurotransmission. Acute administration of carbon-containing Martian dust analogue resulted in a significant decrease in transporter-mediated uptake of L-[14C]glutamate (the major excitatory neurotransmitter) by isolated rat brain nerve terminals. The ambient level of the neurotransmitter in the preparation of nerve terminals increased in the presence of carbon dot-contained Martian dust analogue. These effects were associated with action of carbon component of the upgraded Martian dust stimulant but not with its inorganic constituent.

Novel cookie-with-chocolate carbon dots displaying extremely acidophilic high luminescence

NASA Astrophysics Data System (ADS)

Lu, Siyu; Zhao, Xiaohuan; Zhu, Shoujun; Song, Yubin; Yang, Bai

2014-10-01

A fluorescent carbon dot with a cookie-with-chocolate film structure (about 5 × 5 μm2) showed a high fluorescence quantum yield (61.12%) at low pH. It was hydrothermally synthesized from l-serine and l-tryptophan. The formation mechanism of the film with carbon dots (CDs) was investigated. The film structure was formed by hydrogen bonding and π-π stacking interactions between aromatic rings. The strong blue fluorescence of the CDs increased under strong acidic conditions owing to the changes in the N-groups. These cookie-like CDs are attractive for their potential use as effective fluorescent probes for the sensitive detection of aqueous H+ and Fe3+.A fluorescent carbon dot with a cookie-with-chocolate film structure (about 5 × 5 μm2) showed a high fluorescence quantum yield (61.12%) at low pH. It was hydrothermally synthesized from l-serine and l-tryptophan. The formation mechanism of the film with carbon dots (CDs) was investigated. The film structure was formed by hydrogen bonding and π-π stacking interactions between aromatic rings. The strong blue fluorescence of the CDs increased under strong acidic conditions owing to the changes in the N-groups. These cookie-like CDs are attractive for their potential use as effective fluorescent probes for the sensitive detection of aqueous H+ and Fe3+. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr03965c

26 CFR 1.501(c)(7)-1 - Social clubs.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 26 Internal Revenue 7 2013-04-01 2013-04-01 false Social clubs. 1.501(c)(7)-1 Section 1.501(c)(7... (CONTINUED) INCOME TAXES (CONTINUED) Exempt Organizations § 1.501(c)(7)-1 Social clubs. (a) The exemption... general, this exemption extends to social and recreation clubs which are supported solely by membership...

26 CFR 1.501(c)(7)-1 - Social clubs.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 26 Internal Revenue 7 2012-04-01 2012-04-01 false Social clubs. 1.501(c)(7)-1 Section 1.501(c)(7... (CONTINUED) INCOME TAXES (CONTINUED) Exempt Organizations § 1.501(c)(7)-1 Social clubs. (a) The exemption... general, this exemption extends to social and recreation clubs which are supported solely by membership...

NASA's Space Launch System: Progress Toward the Proving Ground

NASA Technical Reports Server (NTRS)

Jackman, Angie

2017-01-01

Space Launch System will be able to offer payload accommodations with five times more volume than any contemporary launch vehicle. center dot Payload fairings of up to 10-meter diameter are planned. Space Launch System will offer an initial capability of greater than 70 metric tons to low Earth orbit; current U.S. launch vehicle maximum is 28 t. center dot Evolved version of SLS will offer greatest-ever capability of greater than 130 t to LEO. SLS offers reduced transit times to the outer solar system by half or greater. center dot Higher characteristic energy (C3) also enables larger payloads to destination.

Reemergence of enterovirus 71 epidemic in northern Taiwan, 2012.

PubMed

Luo, Shu-Ting; Chiang, Pai-Shan; Chung, Wan-Yu; Chia, Min-Yuan; Tsao, Kuo-Chien; Wang, Ying-Hsiang; Lin, Tzou-Yien; Lee, Min-Shi

2015-01-01

Enterovirus 71 (EV71) belongs to picornavirus family and could be classified phylogenetically into three major genogroups (A, B and C) including 11 genotypes (A, B1-B5 and C1-C5). Since 1997, EV71 has caused large-scale of epidemics with neurological complications in Asian children. In Taiwan, nationwide EV71 epidemics with different predominant genotypes have occurred cyclically since 1998. A nationwide EV71 epidemic occurred again in 2012. We conducted genetic and antigenic characterizations of the 2012 epidemic. Chang Gung Memorial Hospital (CGMH) is a medical center in northern Taiwan. In CGMH, specimens were collected from pediatric inpatients with suspected enterovirus infections for virus isolation. Enterovirus isolates were serotyped and genotyped and sera from EV71 inpatients were collected for measuring neutralizing antibody titers. There were 10, 16 and 99 EV71 inpatients identified in 2010, 2011 and 2012, respectively. There were 82 EV71 isolates genotyped, which identified 17 genotype C4a viruses and 65 genotype B5 viruses. The genotype B5 viruses were not detected until November 2011 and caused epidemics in 2012. Interestingly, the B5-2011 viruses were genetically distinguishable from the B5 viruses causing the 2008 epidemic and are likely introduced from China or Southeastern Asia. Based on antigenic analysis, minor antigenic variations were detected among the B5-2008, B5-2011, C4a-2008 and C4a-2012 viruses but these viruses antigenically differed from genotype A. Genotype B5 and C4a viruses antigenically differ from genotype A viruses which have disappeared globally for 30 years but have been detected in China since 2008. Enterovirus surveillance should monitor genetic and antigenic variations of EV71.

Workshop II: Nanotechnology and Advanced Cell Concepts

NASA Technical Reports Server (NTRS)

2007-01-01

Workshop focused on few emerging concepts(beyond tandem cells): 1. Engineering incident sun spectrum and transparency losses a) Nano emitters (dot concentrator); b) Surface plasmonics; c) Up converters; d) Down converter. 2. Intermediate band solar cells a) Efficiency projections (detail energy balance projections); b) Inserting 0,1 and 2D semiconductor structures in solar cells 3. Polymer and hybrid cells a) Nanotubes/dot polymers; b) Exciton dissociation.

49 CFR 7.43 - When are fees waived or reduced for records requested under subpart C of this part?

Code of Federal Regulations, 2014 CFR

2014-10-01

... first two hours of search time, unless the records are requested for commercial use. (3) Duplication of... of an immediate family member who was, at the time of death, a DOT employee. (e) DOT furnishes... processing of the request or appeal: (1) Search fees otherwise chargeable under § 7.42(h) and (j); and (2...

Nanoscale science and engineering forum (706c) design of solid lipid particles with iron oxide quantum dots for the delivery of therapeutic agents

USDA-ARS?s Scientific Manuscript database

Solid lipid particles provide a method to encapsulate and control the release of drugs in vivo but lack the imaging capability provided by CdS quantum dots. This shortcoming was addressed by combining these two technologies into a model system that uses iron oxide as a non-toxic imaging component in...

75 FR 20387 - Amended Certification Regarding Eligibility To Apply for Worker Adjustment Assistance

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-19

..., Meadville, Pennsylvania. TA-W-71,272C, Crucible Materials Corporation, Crucible Service Center, Troy..., Pennsylvania; Troy, Michigan; Butler, Wisconsin; Miamisburg, Ohio; Chicago, Illinois; Minneapolis, Minnesota...); Troy, Michigan (TA-W-71,272C); Butler, Wisconsin (TA-W-71,272D); Miamisburg, Ohio (TA-W-71,272E...

Highly efficient green up-conversion luminescence of Nd3+-Yb3+-Ho3+ codoped fluorite-type nanocrystals in transparent glass ceramics

NASA Astrophysics Data System (ADS)

Qiu, Jianbei; Kawamoto, Yoji; Zhang, Junjie

2002-11-01

Oxyfluoride glasses were developed with composition 30SiO2[middle dot]15AlO1.5[middle dot]28PbF2[middle dot]22CdF2[middle dot](4.8-x)GdF3[middle dot]0.1NdF3[middle dot]0.1HoF3[middle dot]xYbF3 (x=0, 0.1, 0.2, 0.5, 1, 2, 3, 4, and 4.8) in mole percent. Powder x-ray diffraction analysis revealed that the heat treatments of the oxyfluoride glasses at 450 degC for 0.5 h cause the precipitation of Nd3+-Yb3+-Ho3+ codoped fluorite-type nanocrystals of about 16.3 nm in diameter in the glass matrix. These transparent glass ceramics exhibited very strong green up-conversion luminescence due to the Ho3+: (5F4, 5S2)[right arrow]5I8 transition under 800 nm excitation. The intensity of the green up-conversion luminescence in a 1 mol % YbF3-containing glass ceramic was found to be about 120 times stronger than that in the precursor oxyfluoride glass. The reason for the highly efficient Ho3+ up-conversion luminescence in the oxyfluoride glass ceramics is discussed. An up-conversion mechanism is also proposed.

Combination of short-length TiO2 nanorod arrays and compact PbS quantum-dot thin films for efficient solid-state quantum-dot-sensitized solar cells

NASA Astrophysics Data System (ADS)

Zhang, Zhengguo; Shi, Chengwu; Chen, Junjun; Xiao, Guannan; Li, Long

2017-07-01

Considering the balance of the hole diffusion length and the loading quantity of quantum-dots, the rutile TiO2 nanorod array with the length of 600 nm, the diameter of 20 nm, and the areal density of 500 μm-2 is successfully prepared by the hydrothermal method using the aqueous grown solution of 38 mM titanium isopropoxide and 6 M hydrochloric acid at 170 °C for 105 min. The compact PbS quantum-dot thin film on the TiO2 nanorod array is firstly obtained by the spin-coating-assisted successive ionic layer absorption and reaction with using 1,2-ethanedithiol (EDT). The result reveals that the strong interaction between lead and EDT is very important to control the crystallite size of PbS quantum-dots and obtain the compact PbS quantum-dot thin film on the TiO2 nanorod array. The all solid-state sensitized solar cell with the combination of the short-length, high-density TiO2 nanorod array and the compact PbS quantum-dot thin film achieves the photoelectric conversion efficiency of 4.10%, along with an open-circuit voltage of 0.52 V, a short-circuit photocurrent density of 13.56 mA cm-2 and a fill factor of 0.58.

N-doped carbon dots derived from bovine serum albumin and formic acid with one- and two-photon fluorescence for live cell nuclear imaging.

PubMed

Tan, Mingqian; Li, Xintong; Wu, Hao; Wang, Beibei; Wu, Jing

2015-12-01

Carbon dots with both one- and two-photon fluorescence have drawn great attention for biomedical imaging. Herein, nitrogen-doped carbon dots were facilely developed by one-pot hydrothermal method using bovine serum albumin and formic acid as carbon sources. They are highly water-soluble with strong fluorescence when excited with ultraviolet or near infrared light. The carbon dots have a diameter of ~8.32 nm and can emit strong two-photon induced fluorescence upon excitation at 750 nm with a femtosecond laser. X-ray photoelectron spectrometer analysis revealed that the carbon dots contained three components, C, N and O, corresponding to the peak at 285, 398 and 532 eV, respectively. The Fourier-transform infrared spectroscopy analysis revealed that there are carboxyl and carboxylic groups on the surface, which allowed further linking of functional molecules. pH stability study demonstrated that the carbon dots are able to be used in a wide range of pH values. The fluorescence mechanism is also discussed in this study. Importantly, these carbon dots are biocompatible and highly photostable, which can be directly applied for both one- and two-photon living cell imaging. After proper surface functionalization with TAT peptide, they can be used as fluorescent probes for live cell nuclear-targeted imaging. Copyright © 2015 Elsevier B.V. All rights reserved.

Long-range spin coherence in a strongly coupled all-electronic dot-cavity system

NASA Astrophysics Data System (ADS)

Ferguson, Michael Sven; Oehri, David; Rössler, Clemens; Ihn, Thomas; Ensslin, Klaus; Blatter, Gianni; Zilberberg, Oded

2017-12-01

We present a theoretical analysis of spin-coherent electronic transport across a mesoscopic dot-cavity system. Such spin-coherent transport has been recently demonstrated in an experiment with a dot-cavity hybrid implemented in a high-mobility two-dimensional electron gas [C. Rössler et al., Phys. Rev. Lett. 115, 166603 (2015), 10.1103/PhysRevLett.115.166603] and its spectroscopic signatures have been interpreted in terms of a competition between Kondo-type dot-lead and molecular-type dot-cavity singlet formation. Our analysis brings forward all the transport features observed in the experiments and supports the claim that a spin-coherent molecular singlet forms across the full extent of the dot-cavity device. Our model analysis includes (i) a single-particle numerical investigation of the two-dimensional geometry, its quantum-coral-type eigenstates, and associated spectroscopic transport features, (ii) the derivation of an effective interacting model based on the observations of the numerical and experimental studies, and (iii) the prediction of transport characteristics through the device using a combination of a master-equation approach on top of exact eigenstates of the dot-cavity system, and an equation-of-motion analysis that includes Kondo physics. The latter provides additional temperature scaling predictions for the many-body phase transition between molecular- and Kondo-singlet formation and its associated transport signatures.

Co-Circulation and Genomic Recombination of Coxsackievirus A16 and Enterovirus 71 during a Large Outbreak of Hand, Foot, and Mouth Disease in Central China

PubMed Central

Liu, Weiyong; Wu, Shimin; Xiong, Ying; Li, Tongya; Wen, Zhou; Yan, Mingzhe; Qin, Kai; Liu, Yingle; Wu, Jianguo

2014-01-01

A total of 1844 patients with hand, foot, and mouth disease (HFMD), most of them were children of age 1–3-year-old, in Central China were hospitalized from 2011 to 2012. Among them, 422 were infected with coxsackievirus A16 (CVA16), 334 were infected with enterovirus 71 (EV71), 38 were co-infected with EV71 and CVA16, and 35 were infected with other enteroviruses. Molecular epidemiology analysis revealed that EV71 and CVA16 were detected year-round, but EV71 circulated mainly in July and CVA16 circulated predominantly in November, and incidence of HFMD was reduced in January and February and increased in March. Clinical data showed that hyperglycemia and neurologic complications were significantly higher in EV71-infected patients, while upper respiratory tract infection and C-reactive protein were significantly higher in CVA16-associated patients. 124 EV71 and 80 CVA16 strains were isolated, among them 56 and 68 EV71 strains were C4a and C4b, while 25 and 55 CVA16 strains were B1a and B1b, respectively. Similarity plots and bootscan analyses based on entire genomic sequences revealed that the three C4a sub-genotype EV71 strains were recombinant with C4b sub-genotype EV71 in 2B–2C region, and the three CVA16 strains were recombinant with EV71 in 2A–2B region. Thus, CVA16 and EV71 were the major causative agents in a large HFMD outbreak in Central China. HFMD incidence was high for children among household contact and was detected year-round, but outbreak was seasonal dependent. CVA16 B1b and EV71 C4b reemerged and caused a large epidemic in China after a quiet period of many years. Moreover, EV71 and CVA16 were co-circulated during the outbreak, which may have contributed to the genomic recombination between the pathogens. It should gain more attention as there may be an upward trend in co-circulation of the two pathogens globally and the new role recombination plays in the emergence of new enterovirus variants. PMID:24776922

Evidence for the formation of a novel nitrosothiol from the gaseous mediators nitric oxide and hydrogen sulphide

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

Whiteman, Matthew; Li Ling; Kostetski, Iouri

The gaseous mediators hydrogen sulphide (H{sub 2}S) and nitric oxide ( {sup {center_dot}}NO) are synthesised in the body from L-cysteine and L-arginine, respectively. In the cardiovascular system, {sup {center_dot}}NO is an important regulator of vascular tone and its over- or under-production has been linked to a variety of diseases. The physiological significance of H{sub 2}S is not yet clear but, like {sup {center_dot}}NO, it exhibits vasodilator activity and may play a part in septic and haemorrhagic shock, hypertension, regulation of cardiac contractility, and in inflammation. To date, there have been no reports of a chemical interaction between H{sub 2}S andmore » {sup {center_dot}}NO. Here we show that incubation of the H{sub 2}S donor, sodium hydrosulphide, with a range of {sup {center_dot}}NO donors and {sup {center_dot}}NO gas in vitro leads to the formation of a nitrosothiol molecule as determined by a combination of techniques; electron paramagnetic resonance, amperometry, and measurement of nitrite. We further show that this nitrosothiol did not induce cGMP accumulation in cultured RAW264.7 cells unless {sup {center_dot}}NO was released with Cu{sup 2+}. Finally, using liver homogenates from LPS treated rats we present evidence for the endogenous formation of this nitrosothiol. These findings provide First evidence for the formation of a novel nitrosothiol generated by reaction between H{sub 2}S and {sup {center_dot}}NO. We propose that generation of this nitrosothiol in the body may regulate the physiological effects of both {sup {center_dot}}NO and H{sub 2}S.« less

Quantum-Dot Cellular Automata

NASA Astrophysics Data System (ADS)

Snider, Gregory

2000-03-01

Quantum-dot Cellular Automata (QCA) [1] is a promising architecture which employs quantum dots for digital computation. It is a revolutionary approach that holds the promise of high device density and low power dissipation. A basic QCA cell consists of four quantum dots coupled capacitively and by tunnel barriers. The cell is biased to contain two excess electrons within the four dots, which are forced to opposite "corners" of the four-dot cell by mutual Coulomb repulsion. These two possible polarization states of the cell will represent logic "0" and "1". Properly arranged, arrays of these basic cells can implement Boolean logic functions. Experimental results from functional QCA devices built of nanoscale metal dots defined by tunnel barriers will be presented. The experimental devices to be presented consist of Al islands, which we will call quantum dots, interconnected by tunnel junctions and lithographically defined capacitors. Aluminum/ aluminum-oxide/aluminum tunnel junctions were fabricated using a standard e-beam lithography and shadow evaporation technique. The experiments were performed in a dilution refrigerator at a temperature of 70 mK. The operation of a cell is evaluated by direct measurements of the charge state of dots within a cell as the input voltage is changed. The experimental demonstration of a functioning cell will be presented. A line of three cells demonstrates that there are no metastable switching states in a line of cells. A QCA majority gate will also be presented, which is a programmable AND/OR gate and represents the basic building block of QCA systems. The results of recent experiments will be presented. 1. C.S. Lent, P.D. Tougaw, W. Porod, and G.H. Bernstein, Nanotechnology, 4, 49 (1993).

75 FR 42819 - Airborne Area Navigation Equipment Using Loran-C Inputs

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-22

... Using Loran-C Inputs AGENCY: Federal Aviation Administration (FAA), DOT ACTION: Notice of cancellation of: (1) Loran-C navigation system Technical Standard Orders (TSO); and (2) the revocation of Loran-C... the cancellation of Technical Standard Order (TSO) C-60, Airborne Area Navigation Equipment Using...

75 FR 22674 - Airborne Area Navigation Equipment Using Loran-C Inputs

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-29

... Using Loran-C Inputs AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of cancellation of: (1) Loran-C navigation system Technical Standard Orders (TSO); and (2) the revocation of Loran-C... the cancellation of Technical Standard Order (TSO) C-60, Airborne Area Navigation Equipment Using...

Spiribacter curvatus sp. nov., a moderately halophilic bacterium isolated from a saltern.

PubMed

León, María José; Rodríguez-Olmos, Angel; Sánchez-Porro, Cristina; López-Pérez, Mario; Rodríguez-Valera, Francisco; Soliveri, Juan; Ventosa, Antonio; Copa-Patiño, José Luis

2015-12-01

A novel pink-pigmented bacterial strain, UAH-SP71T, was isolated from a saltern located in Santa Pola, Alicante (Spain) and the complete genome sequence was analysed and compared with that of Spiribacter salinus M19-40T, suggesting that the two strains constituted two separate species, with a 77.3% ANI value. In this paper, strain UAH-SP71T was investigated in a taxonomic study using a polyphasic approach. Strain UAH-SP71T was a Gram-stain-negative, strictly aerobic, non-motile curved rod that grew in media containing 5-20% (w/v) NaCl (optimum 10% NaCl), at 5-40 °C (optimum 37 °C) and at pH 5-10 (optimum pH 8). Phylogenetic analysis based on the comparison of 16S rRNA gene sequences revealed thatstrain UAH-SP71T is a member of the genus Spiribacter, showing a sequence similarity of 96.5% with Spiribacter salinus M19-40T. Other related species are also members of the family Ectothiorhodospiraceae, including Arhodomonas recens RS91T (95.5% 16S rRNA gene sequence similarity), Arhodomonas aquaeolei ATCC 49307T (95.4 %) and Alkalilimnicola ehrlichii MLHE-1T (94.9 %). DNA-DNA hybridization between strain UAH-SP71T and Spiribacter salinus M19-40T was 39 %. The major cellular fatty acids of strain UAH-SP71T were C18 : 1ω6c and/or C18 : 1ω7c, C16 : 0, C16 : 1ω6c and/or C16 : 1ω7c, C10 : 0 3-OH and C12 : 0, a pattern similar to that of Spiribacter salinus M19-40T. Phylogenetic, phenotypic and genotypic differences between strain UAH-SP71T and Spiribacter salinus M19-40T indicate that strainUAH-SP71T represents a novel species of the genus Spiribacter, for which the name Spiribacter curvatus sp. nov. is proposed. The type strain is UAH-SP71T (5CECT8396T5DSM 28542T).

Disorder in KHCO3 as studied by EPR and DTA in Cu2+ doped and gamma-irradiated single crystals

NASA Astrophysics Data System (ADS)

Koksal, F.; Karabulut, B.; Demir, D.; Icbudak, H.; Koseoglu, R.

2005-08-01

Kalicinite (KHCO3) single crystals were investigated by the electron paramagnetric resonance (EPR) technique in their Cu2+ doped and gamma- irradiated states. It is observed that the behavior of the spectrum is the same at ambient and low temperatures down to 113 K in consistence with the monoclinic symmetry of the crystal. However, when the temperature is increased to 313 K, only one site signals were observed at all orientations of the magnetic field for the Cu2+ doped samples as the site splitted signals overlap at this temperature. Furthermore, for the gamma-irradiated crystals, two sites were observed for the induced H(C)over dot O-3 and (C)over dot O-2(-) radicals at ambient temperature for an arbitrary orientation of the magnetic field. However, when the temperature is increased to 348 K, the signals due to the H(C)over dot O-3 radical overlap indicating only one site, but the signals due to (C)over dot O-2(-) the radical do not and continue to indicate the presence of the two sites. Therefore, we conclude that this one site transition at 313 K is due to the disordering of the proton vacancies, as the charge compensation of Cu2+ is fulfilled by K+ and proton holes. This indicates that the proton vacancies come to disorder at 313 K and the protons get disordered at 348 K. The differential thermal analysis results show two small endothermic peaks for the Cu2+ doped and gamma-irradiated samples at 313 and 348 K that were attributed to the disorder of the proton vacancies and protons, in consistency with the EPR results.

Temperature stability of static and dynamic properties of 1.55 µm quantum dot lasers.

PubMed

Abdollahinia, A; Banyoudeh, S; Rippien, A; Schnabel, F; Eyal, O; Cestier, I; Kalifa, I; Mentovich, E; Eisenstein, G; Reithmaier, J P

2018-03-05

Static and dynamic properties of InP-based 1.55 µm quantum dot (QD) lasers were investigated. Due to the reduced size inhomogeneity and a high dot density of the newest generation of 1.55 µm QD gain materials, ridge waveguide lasers (RWG) exhibit improved temperature stability and record-high modulation characteristics. Detailed results are shown for the temperature dependence of static properties including threshold current, voltage-current characteristics, external differential efficiency and emission wavelength. Similarly, small and large signal modulations were found to have only minor dependences on temperature. Moreover, we show the impact of the active region design and the cavity length on the temperature stability. Measurements were performed in pulsed and continuous wave operation. High characteristic temperatures for the threshold current were obtained with T 0 values of 144 K (15 - 60 °C), 101 K (60 - 110 °C) and 70 K up to 180 °C for a 900-µm-long RWG laser comprising 8 QD layers. The slope efficiency in these lasers is nearly independent of temperature showing a T 1 value of more than 900 K up to 110 °C. Due to the high modal gain, lasers with a cavity length of 340 µm reached new record modulation bandwidths of 17.5 GHz at 20 °C and 9 GHz at 80 °C, respectively. These lasers were modulated at 26 GBit/s in the non-return to zero format at 80 °C and at 25 GBaud using a four-level pulse amplitude format at 21 °C.

Hi-C Observations of Penumbral Bright Dots: Comparison with the IRIS Results

NASA Technical Reports Server (NTRS)

Alpert, S. E.; Tiwari, S. K.; Moore, R. L.; Savage, S. L.; Winebarger, A. R.

2014-01-01

We observed bright dots (BDs) in a sunspot penumbra by using data acquired by the High Resolution Coronal Imager (Hi-C). The sizes of these BDs are on the order of 1 arcsecond (1') and are therefore hard to identify using the Atmospheric Imaging Assembly's (AIA) 0.6' pixel -1 resolution. These BDs become readily apparent with Hi-C's 0.1' pixel -1 resolution. Tian et al. (2014) found penumbral BDs in the transition region (TR) by using the Interface Region Imaging Spectrograph (IRIS). However, only a few of their dots could be associated with any enhanced brightness in AIA channels. In this work, we examine the characteristics of the penumbral BDs observed by Hi-C in a sunspot penumbra, including their sizes, lifetimes, speeds, and intensity. We also attempt to relate these BDs to the IRIS BDs. There are fewer Hi-C BDs in the penumbra than seen by IRIS, though different sunspots were studied and Hi-C had a short observation time. We use 193 A Hi-C data from July 11, 2012 which observed from 18:52:00 UT{18:56:00 UT and supplement it with data from AIA's 193 A passband to see the complete lifetime of the dots that were born before and/or lasted longer than Hi-C's 5-minute observation period. We use additional AIA passbands and compare the light curves of the BDs at different temperatures to test whether the Hi-C BDs are TR BDs. We find that most Hi-C BDs show clear movement, and of those that do, they move in a radial direction, toward or away from the sunspot umbra, sometimes doing both. BDs interact with other BDs, combining to fade away or brighten. The BDs that do not interact with other BDs tend to move less and last longer. We examine the properties of the Hi-C BDs and compare them with the IRIS BDs. Our BDs are similar to the exceptional values of the IRIS BDs: they move slower on average and their sizes and lifetimes are on the higher end of the distributions of IRIS BDs. We infer that our penumbral BDs are some of the larger BDs observed by IRIS.

Optimization of soil stabilization with class C fly ash.

DOT National Transportation Integrated Search

1987-01-01

Previous Iowa DOT sponsored research has shown that some Class : C fly ashes are cementitious (because calcium is combined as calcium : aluminates) while other Class C ashes containing similar amounts of : elemental calcium are not (1). Fly ashes fro...

Enterovirus-71 genotype C isolated in Peru between 2006 and 2009.

PubMed

Huaman, Jose L; Carrion, Gladys; Ampuero, Julia S; Ocaña, Victor; Laguna-Torres, V Alberto; Hontz, Robert D

2016-12-01

Enterovirus-71 (EV71) was first isolated in California, United States in 1969, belongs to the genus Enterovirus, family Picornaviridae. Although infection normally causes mild, often undiagnosed illness, it can cause central nervous system infections that could turn fatal. Based on VP1 gene analysis, EV71 has been classified into six separate genotypes. Although the molecular epidemiology of EV71 has been well described via studies originating from Asia and Europe, it is mostly unknown in South America. From our study, four EV71 isolates from Peru were characterized using phylogenetic methods to determine their relationship with known reference strains. These four Peruvian EV71 isolates from between 2006 and 2009 were analyzed by RT-PCR using primers capable of amplifying the entire VP1 gene. Reference strains representing all six known genotypes were used to determine any recognizable phylogenetic relationships. In fact, all of our isolates clustered together within the genotype C1 lineage- separate from Asian, European, North American, and Australian strains. We present evidence that EV71 genotype C1 exists in Peru, and this is the first such report documenting EV71 genotype C1 circulating in South America. Gathering additional isolates will help elucidate a more complete global epidemiological picture of EV71 infections. Published by Elsevier B.V.

InN/InGaN dot-in-a-wire nanostructures emitting at 1.55 µm

NASA Astrophysics Data System (ADS)

Chen, Qiming; Yan, Changling; Qu, Yi

2017-03-01

The room temperature photoluminescence emission at 1.55 µm from InN/In0.7Ga0.3N dot-in-nanowire heterostructures, which was grown on self-assembled GaN nanowires on Si (1 1 1) under N-rich condition by plasma assisted molecular beam epitaxy, has been clarified in this paper. The morphology of the nanowires was uniform along the c-axis as proved by scanning electron microscope, each of the nanowires was grown individually and homogeneously without any coalescence phenomenon respectively. The nanowires dispersed on a silicon substrate showed very clear InN dot-in-nanowire structure by high resolution transmission electron microscopy. The structural properties of the individual InGaN nanocolumn were further investigated by high-angle annular dark field image analysis and energy dispersive x-ray spectrum, which confirmed the successful growth of InN quantum dot embedded in InGaN nanowire.

Beyond attentional bias: a perceptual bias in a dot-probe task.

PubMed

Bocanegra, Bruno R; Huijding, Jorg; Zeelenberg, René

2012-12-01

Previous dot-probe studies indicate that threat-related face cues induce a bias in spatial attention. Independently of spatial attention, a recent psychophysical study suggests that a bilateral fearful face cue improves low spatial-frequency perception (LSF) and impairs high spatial-frequency perception (HSF). Here, we combine these separate lines of research within a single dot-probe paradigm. We found that a bilateral fearful face cue, compared with a bilateral neutral face cue, speeded up responses to LSF targets and slowed down responses to HSF targets. This finding is important, as it shows that emotional cues in dot-probe tasks not only bias where information is preferentially processed (i.e., an attentional bias in spatial location), but also bias what type of information is preferentially processed (i.e., a perceptual bias in spatial frequency). PsycINFO Database Record (c) 2012 APA, all rights reserved.

Electrically driven polarized single-photon emission from an InGaN quantum dot in a GaN nanowire.

PubMed

Deshpande, Saniya; Heo, Junseok; Das, Ayan; Bhattacharya, Pallab

2013-01-01

In a classical light source, such as a laser, the photon number follows a Poissonian distribution. For quantum information processing and metrology applications, a non-classical emitter of single photons is required. A single quantum dot is an ideal source of single photons and such single-photon sources in the visible spectral range have been demonstrated with III-nitride and II-VI-based single quantum dots. It has been suggested that short-wavelength blue single-photon emitters would be useful for free-space quantum cryptography, with the availability of high-speed single-photon detectors in this spectral region. Here we demonstrate blue single-photon emission with electrical injection from an In0.25Ga0.75N quantum dot in a single nanowire. The emitted single photons are linearly polarized along the c axis of the nanowire with a degree of linear polarization of ~70%.

Electrical Characteristics of the Contour-Vibration-Mode Piezoelectric Transformer with Ring/Dot Electrode Area Ratio

NASA Astrophysics Data System (ADS)

Yoo, Juhyun; Yoon, Kwanghee; Lee, Yongwoo; Suh, Sungjae; Kim, Jongsun; Yoo, Chungsik

2000-05-01

Contour-vibration-mode Pb(Sb1/2Nb1/2)O3-Pb(Zr, Ti)O3 [PSN-PZT] piezoelectric transformers with different ring/dot electrode area ratios were fabricated to the size of 27.5× 27.5× 2.5 mm3 by cold isostatic pressing. The electrical properties and characteristic temperature rises caused by the vibration were measured at various load resistances. Efficiencies above 90% with load resistance were obtained from all the transformers. The voltage step-up ratio appeared to be proportional to the dot electrode area. A 14 W fluorescent lamp, T5, was successfully driven by all of the fabricated transformers. The transformer with ring/dot electrode area ratio of 4.85 exhibited the best properties in terms of output power, efficiency and characteristic temperature rise, 14.88 W, 98% and 5°C, respectively.

Self-assembled Metallic Dots and Antidots: Epitaxial Co on Ru(0001)

NASA Astrophysics Data System (ADS)

Yu, Chengtao; Li, Dongqi; Pearson, J.; Bader, S. D.

2001-03-01

We have grown 1-420 nm thick epitaxial Co wedge on Ru(0001) with molecular beam epitaxy at 350^oC to investigate self-assembly in metals utilizing ex-situ atomic force microscopy. A novel growth mode was observed whereby three-dimensional islands (dots) or a flat film network with deep holes (antidots) in truncated pyramidal shapes exist below or above 20 nm, respectively. The tops of the islands and the rims of the holes are flat with a root mean square roughness values of 0.3 nm. The lateral sizes of these dots/antidots, 10^2 nm, tend to be uniform. We postulate that this growth mode, similar to that of self-assembled quantum dots in semiconductors, is mainly driven by strain as a result of an 8% lateral mismatch between the basil plane lattice constants of bulk Co and Ru.

Patterned growth of individual and multiple vertically aligned carbon nanofibers

NASA Astrophysics Data System (ADS)

Merkulov, V. I.; Lowndes, D. H.; Wei, Y. Y.; Eres, G.; Voelkl, E.

2000-06-01

The results of studies of patterned growth of vertically aligned carbon nanofibers (VACNFs) prepared by plasma-enhanced chemical vapor deposition are reported. Nickel (Ni) dots of various diameters and Ni lines with variable widths and shapes were fabricated using electron beam lithography and evaporation, and served for catalytic growth of VACNFs whose structure was determined by high resolution transmission electron microscopy. It is found that upon plasma pre-etching and heating up to 600-700 °C, thin films of Ni break into droplets which initiate the growth of VACNFs. Above a critical dot size multiple droplets are formed, and consequently multiple VACNFs grow from a single evaporated dot. For dot sizes smaller than the critical size only one droplet is formed, resulting in a single VACNF. In the case of a patterned line, the growth mechanism is similar to that from a dot. VACNFs grow along the line, and above a critical linewidth multiple VACNFs are produced across the line. The mechanism of the formation of single and multiple catalyst droplets and subsequently of VACNFs is discussed.

Synthesis of solution-processable poly(3,4 propylenedioxythiophene) nanobelts for electrochromic device applications

NASA Astrophysics Data System (ADS)

Raghavan, Siju Cherikkattil; Shivaprakash, N. Channegowda; Sindhu, Sukumaran Nair

2017-11-01

A new derivative of di-4-isopropyl benzyl substituted propylenedioxythiophene (ProDOT-IPBz2) monomer was synthesized and its resultant polymer was prepared by chemical and electrochemical methods. The chemical polymerization was carried out in a hexane/water reverse microemulsion system using sodium bis(2-ethylhexyl) sulfosuccinate (AOT) as self-assembling template. Chemically synthesized PProDOT-IPBz2 was formed as thin nanobelts with high aspect ratio (3:100), and it was found to be soluble in common organic solvents. The electrochemical and electrochromic (EC) properties of PProDOT-IPBz2 films were studied and it was found that PProDOT-IPBz2 films showed high transparency at oxidized state (+1.0 V) and dark purple color formed at reduced state (-1.0 V). The color contrast of solution cast film was calculated to be 37% T at 550 nm, however electropolymerized PProDOT-IPBz2 film exhibited a color contrast of 48% at 550 nm with switching speed of ∼1 s, and the coloration efficiency was calculated to be 305 cm2C-1.

Location memory for dots in polygons versus cities in regions: evaluating the category adjustment model.

PubMed

Friedman, Alinda; Montello, Daniel R; Burte, Heather

2012-09-01

We conducted 3 experiments to examine the category adjustment model (Huttenlocher, Hedges, & Duncan, 1991) in circumstances in which the category boundaries were irregular schematized polygons made from outlines of maps. For the first time, accuracy was tested when only perceptual and/or existing long-term memory information about identical locations was cued. Participants from Alberta, Canada and California received 1 of 3 conditions: dots-only, in which a dot appeared within the polygon, and after a 4-s dynamic mask the empty polygon appeared and the participant indicated where the dot had been; dots-and-names, in which participants were told that the first polygon represented Alberta/California and that each dot was in the correct location for the city whose name appeared outside the polygon; and names-only, in which there was no first polygon, and participants clicked on the city locations from extant memory alone. Location recall in the dots-only and dots-and-names conditions did not differ from each other and had small but significant directional errors that pointed away from the centroids of the polygons. In contrast, the names-only condition had large and significant directional errors that pointed toward the centroids. Experiments 2 and 3 eliminated the distribution of stimuli and overall screen position as causal factors. The data suggest that in the "classic" category adjustment paradigm, it is difficult to determine a priori when Bayesian cue combination is applicable, making Bayesian analysis less useful as a theoretical approach to location estimation. PsycINFO Database Record (c) 2012 APA, all rights reserved.

The Legionella pneumophila Dot/Icm-secreted Effector PlcC/CegC1 Together with PlcA and PlcB Promotes Virulence and Belongs to a Novel Zinc Metallophospholipase C Family Present in Bacteria and Fungi*

PubMed Central

Aurass, Philipp; Schlegel, Maren; Metwally, Omar; Harding, Clare R.; Schroeder, Gunnar N.; Frankel, Gad; Flieger, Antje

2013-01-01

Legionella pneumophila is a water-borne bacterium that causes pneumonia in humans. PlcA and PlcB are two previously defined L. pneumophila proteins with homology to the phosphatidylcholine-specific phospholipase C (PC-PLC) of Pseudomonas fluorescens. Additionally, we found that Lpg0012 shows similarity to PLCs and has been shown to be a Dot/Icm-injected effector, CegC1, which is designated here as PlcC. It remained unclear, however, whether these L. pneumophila proteins exhibit PLC activity. PlcC expressed in Escherichia coli hydrolyzed a broad phospholipid spectrum, including PC, phosphatidylglycerol (PG), and phosphatidylinositol. The addition of Zn2+ ions activated, whereas EDTA inhibited, PlcC-derived PLC activity. Protein homology search revealed that the three Legionella enzymes and P. fluorescens PC-PLC share conserved domains also present in uncharacterized fungal proteins. Fifteen conserved amino acids were essential for enzyme activity as identified via PlcC mutagenesis. Analysis of defined L. pneumophila knock-out mutants indicated Lsp-dependent export of PG-hydrolyzing PLC activity. PlcA and PlcB exhibited PG-specific activity and contain a predicted Sec signal sequence. In line with the reported requirement of host cell contact for Dot/Icm-dependent effector translocation, PlcC showed cell-associated PC-specific PLC activity after bacterial growth in broth. A PLC triple mutant, but not single or double mutants, exhibited reduced host killing in a Galleria mellonella infection model, highlighting the importance of the three PLCs in pathogenesis. In summary, we describe here a novel Zn2+-dependent PLC family present in Legionella, Pseudomonas, and fungi with broad substrate preference and function in virulence. PMID:23457299

The Legionella pneumophila Dot/Icm-secreted effector PlcC/CegC1 together with PlcA and PlcB promotes virulence and belongs to a novel zinc metallophospholipase C family present in bacteria and fungi.

PubMed

Aurass, Philipp; Schlegel, Maren; Metwally, Omar; Harding, Clare R; Schroeder, Gunnar N; Frankel, Gad; Flieger, Antje

2013-04-19

Legionella pneumophila is a water-borne bacterium that causes pneumonia in humans. PlcA and PlcB are two previously defined L. pneumophila proteins with homology to the phosphatidylcholine-specific phospholipase C (PC-PLC) of Pseudomonas fluorescens. Additionally, we found that Lpg0012 shows similarity to PLCs and has been shown to be a Dot/Icm-injected effector, CegC1, which is designated here as PlcC. It remained unclear, however, whether these L. pneumophila proteins exhibit PLC activity. PlcC expressed in Escherichia coli hydrolyzed a broad phospholipid spectrum, including PC, phosphatidylglycerol (PG), and phosphatidylinositol. The addition of Zn(2+) ions activated, whereas EDTA inhibited, PlcC-derived PLC activity. Protein homology search revealed that the three Legionella enzymes and P. fluorescens PC-PLC share conserved domains also present in uncharacterized fungal proteins. Fifteen conserved amino acids were essential for enzyme activity as identified via PlcC mutagenesis. Analysis of defined L. pneumophila knock-out mutants indicated Lsp-dependent export of PG-hydrolyzing PLC activity. PlcA and PlcB exhibited PG-specific activity and contain a predicted Sec signal sequence. In line with the reported requirement of host cell contact for Dot/Icm-dependent effector translocation, PlcC showed cell-associated PC-specific PLC activity after bacterial growth in broth. A PLC triple mutant, but not single or double mutants, exhibited reduced host killing in a Galleria mellonella infection model, highlighting the importance of the three PLCs in pathogenesis. In summary, we describe here a novel Zn(2+)-dependent PLC family present in Legionella, Pseudomonas, and fungi with broad substrate preference and function in virulence.

Enhanced photovoltaic property by forming p-i-n structures containing Si quantum dots/SiC multilayers

PubMed Central

2014-01-01

Si quantum dots (Si QDs)/SiC multilayers were fabricated by annealing hydrogenated amorphous Si/SiC multilayers prepared in a plasma-enhanced chemical vapor deposition system. The thickness of amorphous Si layer was designed to be 4 nm, and the thickness of amorphous SiC layer was kept at 2 nm. Transmission electron microscopy observation revealed the formation of Si QDs after 900°C annealing. The optical properties of the Si QDs/SiC multilayers were studied, and the optical band gap deduced from the optical absorption coefficient result is 1.48 eV. Moreover, the p-i-n structure with n-a-Si/i-(Si QDs/SiC multilayers)/p-Si was fabricated, and the carrier transportation mechanism was investigated. The p-i-n structure was used in a solar cell device. The cell had the open circuit voltage of 532 mV and the power conversion efficiency (PCE) of 6.28%. PACS 81.07.Ta; 78.67.Pt; 88.40.jj PMID:25489285

Tetragonal zirconia quantum dots in silica matrix prepared by a modified sol-gel protocol

NASA Astrophysics Data System (ADS)

Verma, Surbhi; Rani, Saruchi; Kumar, Sushil

2018-05-01

Tetragonal zirconia quantum dots (t-ZrO2 QDs) in silica matrix with different compositions ( x)ZrO2-(100 - x)SiO2 were fabricated by a modified sol-gel protocol. Acetylacetone was added as a chelating agent to zirconium propoxide to avoid precipitation. The powders as well as thin films were given thermal treatment at 650, 875 and 1100 °C for 4 h. The silica matrix remained amorphous after thermal treatment and acted as an inert support for zirconia quantum dots. The tetragonal zirconia embedded in silica matrix transformed into monoclinic form due to thermal treatment ≥ 1100 °C. The stability of tetragonal phase of zirconia is found to enhance with increase in silica content. A homogenous dispersion of t-ZrO2 QDs in silica matrix was indicated by the mapping of Zr, Si and O elements obtained from scanning electron microscope with energy dispersive X-ray analyser. The transmission electron images confirmed the formation of tetragonal zirconia quantum dots embedded in silica. The optical band gap of zirconia QDs (3.65-5.58 eV) was found to increase with increase in zirconia content in silica. The red shift of PL emission has been exhibited with increase in zirconia content in silica.

Tuning Optoelectronic Properties of the Graphene-Based Quantum Dots C16- xSi xH10 Family.

PubMed

Ramadan, F-Z; Ouarrad, H; Drissi, L B

2018-06-07

The electronic and optical properties of graphene-based quantum dots (QDs) are investigated using DFT and many-body perturbation theory. Formation energy, hardeness and electrophilicity show that all structures, from pyrene to silicene QD passing through 15 CSi QD configurations, are energetically and chemically stable. It is also found that they are reactive which implies their favorable character for the possible electronic transport and conductivity. The electronic and optical properties are very sensitive to the number and position of the substituted silicon atoms as well as the directions of the light polarization. Moreover, quantum confinement effects make the exciton binding energy of CSi quantum dots larger than those of their higher dimensional allotropes such as silicene, graphene, and SiC sheet and nanotube. It is also higher those of other shapes of quantum dots like hexagonal graphene QDs and can be tailored from the ultraviolet region to the visible one. The values of the singlet-triplet splitting determined for the X- and Y-light polarized indicate that all configurations have a high fluorescence quantum yield compared to the yield of typical semiconductors, which makes them very promising for various applications such as the light-emitting diode material and nanomedicine.

Quantum-Dot-Based Lateral Flow Immunoassay for Detection of Neonicotinoid Residues in Tea Leaves.

PubMed

Wang, Shuangjie; Liu, Ying; Jiao, Shasha; Zhao, Ying; Guo, Yirong; Wang, Mengcen; Zhu, Guonian

2017-11-22

Neonicotinoid insecticides are commonly used for pest control on tea plantations as a result of their broad-spectrum activity. However, neonicotinoid residues released from tea leaves into tea infusions pose a dietary risk to consumers. Therefore, a rapid, sensitive, and reliable on-site detection method for neonicotinoids is needed. We developed a quantum-dot-based fluorescent lateral flow immunochromatographic strip (LFICS) combined with a broad-specific antibody for detection of typical neonicotinoids (imidacloprid, imidaclothiz, and clothianidin), with sensitivities [50% inhibitory concentration (IC 50 )] of 0.104-0.33 ng/mL and visual detection limits of 0.5-1 ng/mL. The strip assay could be completed in less than 30 min. Using the LFICS to analyze spiked tea samples (green tea, black tea, and oolong tea), the average recovery of the three neonicotinoids ranged between 71 and 111%, with the coefficient of variation below 12%. The results from the LFICS tests for field samples were consistent with results from ultraperformance liquid chromatography-tandem mass spectrometry. The newly developed strip is a useful tool for the on-site detection of neonicotinoid residues in tea.

Cost-effectiveness of meglumine antimoniate versus miltefosine caregiver DOT for the treatment of pediatric cutaneous leishmaniasis

PubMed Central

Cossio, Alexandra; Saravia, Nancy Gore; Castro, Maria del Mar; Prada, Sergio; Bartlett, Allison H.; Pho, Mai T.

2017-01-01

Background Oral miltefosine has been shown to be non-inferior to first-line, injectable meglumine antimoniate (MA) for the treatment of cutaneous leishmaniasis (CL) in children. Miltefosine may be administered via in-home caregiver Directly Observed Therapy (cDOT), while patients must travel to clinics to receive MA. We performed a cost-effectiveness analysis comparing miltefosine by cDOT versus MA for pediatric CL in southwest Colombia. Methodology/Principle findings We developed a Monte Carlo model comparing the cost-per-cure of miltefosine by cDOT compared to MA from patient, government payer, and societal perspectives (societal = sum of patient and government payer perspective costs). Drug effectiveness and adverse events were estimated from clinical trials. Healthcare utilization and costs of travel were obtained from surveys of providers and published sources. The primary outcome was cost-per-cure reported in 2015 USD. Treatment efficacy, costs, and adherence were varied in sensitivity analysis to assess robustness of results. Treatment with miltefosine resulted in substantially lower cost-per-cure from a societal and patient perspective, and slightly higher cost-per-cure from a government payer perspective compared to MA. Mean societal cost-per-cure were $531 (SD±$239) for MA and $188 (SD±$100) for miltefosine, a mean cost-per-cure difference of +$343. Mean cost-per-cure from a patient perspective were $442 (SD ±$233) for MA and $30 (SD±$16) for miltefosine, a mean difference of +$412. Mean cost-per-cure from a government perspective were $89 (SD±$55) for MA and $158 (SD±$98) for miltefosine, with a mean difference of -$69. Results were robust across a variety of assumptions in univariate and multi-way analysis. Conclusions/Significance Treatment of pediatric cutaneous leishmaniasis with miltefosine via cDOT is cost saving from patient and societal perspectives, and moderately more costly from the government payer perspective compared to treatment with MA. Results were robust over a range of sensitivity analyses. Lower drug price for miltefosine could result in cost saving from a government perspective. PMID:28384261

Enterovirus 71 2C Protein Inhibits NF-κB Activation by Binding to RelA(p65)

PubMed Central

Du, Haiwei; Yin, Peiqi; Yang, Xiaojie; Zhang, Leiliang; Jin, Qi; Zhu, Guofeng

2015-01-01

Viruses evolve multiple ways to interfere with NF-κB signaling, a key regulator of innate and adaptive immunity. Enterovirus 71 (EV71) is one of primary pathogens that cause hand-foot-mouth disease. Here, we identify RelA(p65) as a novel binding partner for EV71 2C protein from yeast two-hybrid screen. By interaction with IPT domain of p65, 2C reduces the formation of heterodimer p65/p50, the predominant form of NF-κB. We also show that picornavirus 2C family proteins inhibit NF-κB activation and associate with p65 and IKKβ. Our findings provide a novel mechanism how EV71 antagonizes innate immunity. PMID:26394554

Transport properties of coupled quantum dots in the presence of phonons

NASA Astrophysics Data System (ADS)

Martins, G.; Al-Hassanieh, K.

2005-03-01

Here is presented the numerical study of the effect of Holstein phonons in the transport properties of two coupled quantum dots (QDs) in the Kondo regime. For the QDs we use the Anderson impurity model and each QD is coupled to a different Holstein mode. At T=0, in the absence of phonons, and with 1 electron per dot, the usual splitting of the Kondo resonance is observed.^1 When the QDs are coupled to the phonons, there is a reduction of the effective Coulomb repulsion, which is explained through a canonical transformation. In addition, the conductance at the electron-hole symmetric gate potential is not affected by the phonons. This is caused by the modulation of the coupling factors.^2 The difference between the effects of phonons in lithographic QDs and in molecular conductors is also discussed. 1- C.A. Büsser et al, Phys. Rev. B 62, 9907 (2000). 2- K.A. Al-Hassanieh, C.A. Büsser, G.B. Martins, Adriana Moreo and Elbio Dagotto (preprint)

A real-time spectrum acquisition system design based on quantum dots-quantum well detector

NASA Astrophysics Data System (ADS)

Zhang, S. H.; Guo, F. M.

2016-01-01

In this paper, we studied the structure characteristics of quantum dots-quantum well photodetector with response wavelength range from 400 nm to 1000 nm. It has the characteristics of high sensitivity, low dark current and the high conductance gain. According to the properties of the quantum dots-quantum well photodetectors, we designed a new type of capacitive transimpedence amplifier (CTIA) readout circuit structure with the advantages of adjustable gain, wide bandwidth and high driving ability. We have implemented the chip packaging between CTIA-CDS structure readout circuit and quantum dots detector and tested the readout response characteristics. According to the timing signals requirements of our readout circuit, we designed a real-time spectral data acquisition system based on FPGA and ARM. Parallel processing mode of programmable devices makes the system has high sensitivity and high transmission rate. In addition, we realized blind pixel compensation and smoothing filter algorithm processing to the real time spectrum data by using C++. Through the fluorescence spectrum measurement of carbon quantum dots and the signal acquisition system and computer software system to realize the collection of the spectrum signal processing and analysis, we verified the excellent characteristics of detector. It meets the design requirements of quantum dot spectrum acquisition system with the characteristics of short integration time, real-time and portability.

Properties of strong-coupling magneto-bipolaron qubit in quantum dot under magnetic field

NASA Astrophysics Data System (ADS)

Xu-Fang, Bai; Ying, Zhang; Wuyunqimuge; Eerdunchaolu

2016-07-01

Based on the variational method of Pekar type, we study the energies and the wave-functions of the ground and the first-excited states of magneto-bipolaron, which is strongly coupled to the LO phonon in a parabolic potential quantum dot under an applied magnetic field, thus built up a quantum dot magneto-bipolaron qubit. The results show that the oscillation period of the probability density of the two electrons in the qubit decreases with increasing electron-phonon coupling strength α, resonant frequency of the magnetic field ω c, confinement strength of the quantum dot ω 0, and dielectric constant ratio of the medium η the probability density of the two electrons in the qubit oscillates periodically with increasing time t, angular coordinate φ 2, and dielectric constant ratio of the medium η the probability of electron appearing near the center of the quantum dot is larger, and the probability of electron appearing away from the center of the quantum dot is much smaller. Project supported by the Natural Science Foundation of Hebei Province, China (Grant No. E2013407119) and the Items of Institution of Higher Education Scientific Research of Hebei Province and Inner Mongolia, China (Grant Nos. ZD20131008, Z2015149, Z2015219, and NJZY14189).

Response of optically stimulated luminescence dosimeters subjected to X-rays in diagnostic energy range

NASA Astrophysics Data System (ADS)

Musa, Y.; Hashim, S.; Karim, M. K. A.; Bakar, K. A.; Ang, W. C.; Salehhon, N.

2017-05-01

The use of optically stimulated luminescence (OSL) for dosimetry applications has recently increased considerably due to availability of commercial OSL dosimeters (nanoDots) for clinical use. The OSL dosimeter has a great potential to be used in clinical dosimetry because of its prevailing advantages in both handling and application. However, utilising nanoDot OSLDs for dose measurement in diagnostic radiology can only be guaranteed when the performance and characteristics of the dosimeters are apposite. In the present work, we examined the response of commercially available nanoDot OSLD (Al2O3:C) subjected to X-rays in general radiography. The nanoDots response with respect to reproducibility, dose linearity and signal depletion were analysed using microStar reader (Landauer, Inc., Glenwood, IL). Irradiations were performed free-in-air using 70, 80 and 120 kV tube voltages and tube currents ranging from 10 - 100 mAs. The results showed that the nanoDots exhibit good linearity and reproducibility when subjected to diagnostic X-rays, with coefficient of variations (CV) ranging between 2.3% to 3.5% representing a good reproducibility. The results also indicated average of 1% signal reduction per readout. Hence, the nanoDots showed a promising potential for dose measurement in general X-ray procedure.

Highly Conserved Keratin-Associated Protein 7-1 Gene in Yak, Taurine and Zebu Cattle.

PubMed

Arlud, S; He, N; Sari, E M; Ma, Z-J; Zhang, H; An, T-W; Han, J-L

2017-01-01

Keratin-associated proteins (KRTAPs) play a critical role in cross-linking the keratin intermediate filaments to build a hair shaft. The genetic polymorphisms of the bovine KRTAP7-1 gene were investigated for the first time in this study. The complete coding sequence of the KRTAP7-1 gene in 108 domestic yak, taurine and zebu cattle from China and Indonesia were successfully amplified using polymerase chain reaction and then directly sequenced. Only two single-nucleotide polymorphisms (one nonsynonymous at c.7C/G and another synonymous at c.21C/T) and three haplotypes (BOVIN-KRTAP7-1*A, B and C) were identified in the complete coding sequence of the bovine KRTAP7-1 gene among all animals. There was no polymorphism across three Chinese indigenous yak breeds and one Indonesian zebu cattle population, all sharing the BOVINKRTAP71*A haplotype. The four taurine cattle populations also had BOVIN-KRTAP7-1*A as the most common haplotype with a frequency of 0.80. The frequency of novel haplotype BOVIN-KRTAP7-1*B was only 0.07 present in one heterozygous animal in each of the four taurine cattle populations, while BOVINKRTAP7- 1*C was only found in a Simmental and a local Chinese Yellow cattle population with frequencies of 0.17 and 0.36, respectively. The monomorphic yak KRTAP7-1 gene in particular, and highly conserved bovine, sheep and goat KRTAP7-1 genes in general, demonstrated its unique intrinsic structural property (e.g., > 21% high glycine content) and primary functional importance in supporting the mechanical strength and shape of hair.

Space Radar Image of Boston, Massachusetts

NASA Technical Reports Server (NTRS)

1994-01-01

This radar image of the area surrounding Boston, Mass., shows how a spaceborne radar system distinguishes between densely populated urban areas and nearby areas that are relatively unsettled. The bright white area at the right center of the image is downtown Boston. The wide river below and to the left of the city is the Charles River in Boston's Back Bay neighborhood. The dark green patch to the right of the Back Bay is Boston Common. A bridge across the north end of Back Bay connects the cities of Boston and Cambridge. The light green areas that dominate most of the image are the suburban communities surrounding Boston. The many ponds that dot the region appear as dark irregular spots. Many densely populated urban areas show up as red in the image due to the alignment of streets and buildings to the incoming radar beam. North is toward the upper left. The image was acquired on October 9, 1994, by the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) as it flew aboard the space shuttle Endeavour. This area is centered at 42.4 degrees north latitude, 71.2 degrees west longitude. The area shown is approximately 37 km by 18 km (23 miles by 11 miles). Colors are assigned to different radar frequencies and polarizations as follows: red is L-band horizontally transmitted, horizontally received; green is L-band horizontally transmitted, vertically received; blue is C-band horizontally transmitted, vertically received. SIR-C/X-SAR, a cooperative mission of the German, Italian and United States space agencies, is part of NASA's Mission to Planet Earth program.

75 FR 27973 - Airworthiness Directives; Rolls-Royce plc RB211-524C2 Series Turbofan Engines

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-19

... RB211-524C2 Series Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice... Rolls-Royce plc (RR) model RB211-524C2-19 and RB211-524C2-B-19 turbofan engines. These engines are...

Optical Pumping of the Electronic and Nuclear Spin of Single Charge-Tunable Quantum Dots

DTIC Science & Technology

2005-02-02

Optical Pumping of the Electronic and Nuclear Spin of Single Charge-Tunable Quantum Dots A. S . Bracker,1 E. A. Stinaff,1 D. Gammon,1 M. E. Ware,1 J...G. Tischler,1 A. Shabaev,1 Al. L. Efros,1 D. Park,1 D. Gershoni,2 V. L. Korenev ,3 and I. A. Merkulov3 1Naval Research Laboratory, Washington, D.C...intensity (open circles), the PRL 94, 047402 (2005) P H Y S I C A L R E V I E W L E T T E R S week ending 4 FEBRUARY 2005 0031-9007=05=94(4)=047402(4

In vivo toxicity assessment of non-cadmium quantum dots in BALB/c mice.

PubMed

Lin, Guimiao; Ouyang, Qingling; Hu, Rui; Ding, Zhangchi; Tian, Jinglin; Yin, Feng; Xu, Gaixia; Chen, Qiang; Wang, Xiaomei; Yong, Ken-Tye

2015-02-01

Along with widespread usage of QDs in electronic and biomedical industries, the likelihood of QDs exposure to the environment and humans is deemed to occur when the QD products are degraded or handled as waste for processing. To date, there are very few toxicological reports available in the literature for non-cadmium QDs in animal models. In this work, we studied the long term in vivo toxicity of InP/ZnS QDs in BALB/c mice. The biodistribution, body weight, hematology, blood biochemistry, and organ histology were determined at a very high dosage (25 mg/kg) of InP/ZnS QDs over 84 days period. Our results manifested that the QDs formulation did not result in observable toxicity in vivo within the evaluation period, thereby suggesting that the InP/ZnS QDs can be utilized as optical probes or nanocarrier for selected in vivo biological applications when an optimized dosage is employed. This study investigated the toxicity of quantum dots in BALB/c mice, and concluded that no organotoxicity was detectable despite of using high concentration of InP/ZnS quantum dots with prolonged exposure of 3 months. Copyright © 2015 Elsevier Inc. All rights reserved.

Electrically pumped 1.3 microm room-temperature InAs/GaAs quantum dot lasers on Si substrates by metal-mediated wafer bonding and layer transfer.

PubMed

Tanabe, Katsuaki; Guimard, Denis; Bordel, Damien; Iwamoto, Satoshi; Arakawa, Yasuhiko

2010-05-10

An electrically pumped InAs/GaAs quantum dot laser on a Si substrate has been demonstrated. The double-hetero laser structure was grown on a GaAs substrate by metal-organic chemical vapor deposition and layer-transferred onto a Si substrate by GaAs/Si wafer bonding mediated by a 380-nm-thick Au-Ge-Ni alloy layer. This broad-area Fabry-Perot laser exhibits InAs quantum dot ground state lasing at 1.31 microm at room temperature with a threshold current density of 600 A/cm(2). (c) 2010 Optical Society of America.

Ensemble and single particle photophysical properties (two-photon excitation, anisotropy, FRET, lifetime, spectral conversion) of commercial quantum dots in solution and in live cells.

PubMed

Grecco, H E; Lidke, K A; Heintzmann, R; Lidke, D S; Spagnuolo, C; Martinez, O E; Jares-Erijman, E A; Jovin, T M

2004-11-01

In this work, we characterized streptavidin-conjugated quantum dots (QDs) manufactured by Quantum Dot Corporation. We present data on: (1) two-photon excitation; (2) fluorescence lifetimes; (3) ensemble and single QD emission anisotropy; (4) QDs as donors for Forster resonance energy transfer (FRET); and (5) spectral conversion of QDs exposed to high-intensity illumination. We also demonstrate the utility of QDs for (1) imaging the binding and uptake of biotinylated transferrin on living cells, and (2) resolving by fluorescence lifetime imaging microscopy (FLIM) signals originating from QDs from those of spatially and spectrally overlapping visible fluorescent proteins (VFPs). (c) 2005 Wiley-Liss, Inc.

Thiolated graphene - a new platform for anchoring CdSe quantum dots for hybrid heterostructures

NASA Astrophysics Data System (ADS)

Debgupta, Joyashish; Pillai, Vijayamohanan K.

2013-04-01

Effective organization of small CdSe quantum dots on graphene sheets has been achieved by a simple solution exchange with thiol terminated graphene prepared by diazonium salt chemistry. This generic methodology of CdSe QD attachment to any graphene surface has remarkable implications in designing hybrid heterostructures.Effective organization of small CdSe quantum dots on graphene sheets has been achieved by a simple solution exchange with thiol terminated graphene prepared by diazonium salt chemistry. This generic methodology of CdSe QD attachment to any graphene surface has remarkable implications in designing hybrid heterostructures. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr00363a

Nitrogen and sulfur co-doped carbon dots with strong blue luminescence

NASA Astrophysics Data System (ADS)

Ding, Hui; Wei, Ji-Shi; Xiong, Huan-Ming

2014-10-01

Sulfur-doped carbon dots (S-CDs) with a quantum yield (QY) of 5.5% and nitrogen, sulfur co-doped carbon dots (N,S-CDs) with a QY of 54.4% were synthesized, respectively, via the same hydrothermal route using α-lipoic acid as the carbon source. The obtained S-CDs and N,S-CDs had similar sizes but different optical features. The QY of N,S-CDs was gradually enhanced when extending the reaction time to increase the nitrogen content. After careful characterization of these CDs, the doped nitrogen element was believed to be in the form of C&z.dbd;N and C-N bonds which enhanced the fluorescence efficiency significantly. Meanwhile, the co-doped sulfur element was found to be synergistic for nitrogen doping in N,S-CDs. The optimal N,S-CDs were successfully employed as good multicolor cell imaging probes due to their fine dispersion in water, excitation-dependent emission, excellent fluorescence stability and low toxicity. Besides, such N,S-CDs showed a wide detection range and excellent accuracy as fluorescent sensors for Fe3+ ions.Sulfur-doped carbon dots (S-CDs) with a quantum yield (QY) of 5.5% and nitrogen, sulfur co-doped carbon dots (N,S-CDs) with a QY of 54.4% were synthesized, respectively, via the same hydrothermal route using α-lipoic acid as the carbon source. The obtained S-CDs and N,S-CDs had similar sizes but different optical features. The QY of N,S-CDs was gradually enhanced when extending the reaction time to increase the nitrogen content. After careful characterization of these CDs, the doped nitrogen element was believed to be in the form of C&z.dbd;N and C-N bonds which enhanced the fluorescence efficiency significantly. Meanwhile, the co-doped sulfur element was found to be synergistic for nitrogen doping in N,S-CDs. The optimal N,S-CDs were successfully employed as good multicolor cell imaging probes due to their fine dispersion in water, excitation-dependent emission, excellent fluorescence stability and low toxicity. Besides, such N,S-CDs showed a wide detection range and excellent accuracy as fluorescent sensors for Fe3+ ions. Electronic supplementary information (ESI) available: Experimental details and comparable characterization of three kinds of CDs. See DOI: 10.1039/c4nr04267k

In vitro detection of canine distemper virus nucleic acid with a virus-specific cDNA probe by dot-blot and in situ hybridization.

PubMed

Oglesbee, M; Jackwood, D; Perrine, K; Axthelm, M; Krakowka, S; Rice, J

1986-11-01

A cDNA library was prepared from canine distemper viral (CDV) messenger RNA (mRNA) derived from Vero cells lytically infected with the Onderstepoort strain (Ond) of CDV. A 300 base pair insert was identified which, by Northern blot analysis and Sanger sequence data, was shown to be specific to the nucleocapsid gene. The nucleocapsid (NC) clone was radiolabelled with 32P using nick translation and used to detect viral RNA in both dot-blot and in situ preparations of Vero cells lytically infected with Onderstepoort CDV (Ond-CDV) and immortalized mink lung cells persistently infected with racoon origin CDV (CCL64-RCDV). Dot-blot hybridization results paralleled immunofluorescent results in the lytically infected cells. In 18 persistently infected cell lines from the RCDV-CCL64 parental stock, 13 lines were positive and two were negative on both immunofluorescence and dot-blot hybridization analysis for CDV antigen and RNA, respectively. Viral nucleic acid was detected in these persistently infected cells, where as few as 1.9% of the members of a line were positive on immunofluorescence. A dot-blot autoradiographic signal was obtained in three lines which were negative for CDV antigen. CDV RNA was detected in both lytically and persistently infected cell lines by in situ hybridization, where decreasing probe length was important in increasing the sensitivity of this assay. Viral RNA was detected in over 90% of the lytically infected cells, where only 70% were positive for viral antigen by immunofluorescence.

Coxiella burnetii Employs the Dot/Icm Type IV Secretion System to Modulate Host NF-κB/RelA Activation

PubMed Central

Mahapatra, Saugata; Gallaher, Brandi; Smith, Sydni Caet; Graham, Joseph G.; Voth, Daniel E.; Shaw, Edward I.

2016-01-01

Coxiella burnetii is the causative agent of Q fever and an obligate intracellular pathogen in nature that survives and grows in a parasitophorous vacuole (PV) within eukaryotic host cells. C. burnetii promotes intracellular survival by subverting apoptotic and pro-inflammatory signaling pathways that are typically regulated by nuclear transcription factor-κB (NF-κB). We and others have demonstrated that C. burnetii NMII proteins inhibit expression of pro-inflammatory cytokines and induce expression of anti-apoptotic genes during infection. Here, we demonstrate that C. burnetii promotes intracellular survival by modulating NF-κB subunit p65 (RelA) phosphorylation, and thus activation, in a Type Four B Secretion System (T4BSS)-dependent manner. Immunoblot analysis of RelA phosphorylated at serine-536 demonstrated that C. burnetii increases NF-κB activation via the canonical pathway. However, RelA phosphorylation levels were even higher in infected cells where bacterial protein or mRNA synthesis was inhibited. Importantly, we demonstrate that inhibition of RelA phosphorylation impairs PV formation and C. burnetii growth. We found that a T4BSS-defective mutant (CbΔdotA) elicited phosphorylated RelA levels similar to those of wild type C. burnetii infection treated with Chloramphenicol. Moreover, cells infected with CbΔdotA or wild type C. burnetii treated with Chloramphenicol showed similar levels of GFP-RelA nuclear localization, and significantly increased localization compared to wild type C. burnetii infection. These data indicate that without de novo protein synthesis and a functional T4BSS, C. burnetii is unable to modulate NF-κB activation, which is crucial for optimal intracellular growth. PMID:28066723

Assessment of professional baseball players aerobic exercise performance depending on their positions.

PubMed

Yang, Seung-Won

2014-11-01

This study reports the average and SD of professional baseball players' cardiorespiratory endurance, maximum oxygen consumption, oxygen consumption during anaerobic threshold, maximum oxygen consumption of anaerobic threshold %, maximum heart rate, and heart rate of anaerobic threshold. We also report the comparison between pitchers and fielders. Considering the total number of results, percentile was used and results were classified into 5 grades. One professional baseball players' organization with more than 14 years of experience participated in this study. First, we observed that the average pitchers' V[Combining Dot Above]O2max was 53.64 ml·kg·min, whereas the average fielders' was 52.30 ml·kg·min. These values were lower than other sports players. Second, in case of the V[Combining Dot Above]O2AT, pitchers showed 39.35 ml·kg·min and fielders showed 39.96 ml·kg·min. %V[Combining Dot Above]O2AT showed a significant difference of 71.13% between pitchers and fielders-pitchers, whereas fielders showed 73.89% (p < 0.01). Third, maximal heart rates were measured at 188.69 b·min (pitchers) and 187.79 b·min (fielders). These were lower than college baseball players and higher than other sports players. In conclusion, both professional baseball pitchers and fielders should be aware of the necessity of systematic cardiorespiratory endurance data analysis. Moreover, baseball teams, athletic trainers, and coaches should also be aware of the importance of cardiorespiratory endurance.

Near-identical star formation rate densities from Hα and FUV at redshift zero

NASA Astrophysics Data System (ADS)

Audcent-Ross, Fiona M.; Meurer, Gerhardt R.; Wong, O. I.; Zheng, Z.; Hanish, D.; Zwaan, M. A.; Bland-Hawthorn, J.; Elagali, A.; Meyer, M.; Putman, M. E.; Ryan-Weber, E. V.; Sweet, S. M.; Thilker, D. A.; Seibert, M.; Allen, R.; Dopita, M. A.; Doyle-Pegg, M. T.; Drinkwater, M.; Ferguson, H. C.; Freeman, K. C.; Heckman, T. M.; Kennicutt, R. C.; Kilborn, V. A.; Kim, J. H.; Knezek, P. M.; Koribalski, B.; Smith, R. C.; Staveley-Smith, L.; Webster, R. L.; Werk, J. K.

2018-06-01

For the first time both Hα and far-ultraviolet (FUV) observations from an H I-selected sample are used to determine the dust-corrected star formation rate density (SFRD: \\dot{ρ }) in the local Universe. Applying the two star formation rate indicators on 294 local galaxies we determine log(\\dot{ρ } _{Hα }) = -1.68 ^{+0.13}_{-0.05} [M⊙ yr-1 Mpc-3] and log(\\dot{ρ }_{FUV}) = -1.71 ^{+0.12}_{-0.13} [M⊙ yr-1 Mpc-3]. These values are derived from scaling Hα and FUV observations to the H I mass function. Galaxies were selected to uniformly sample the full H I mass (M_{H I}) range of the H I Parkes All-Sky Survey (M_{H I} ˜ 107 to ˜1010.7 M⊙). The approach leads to relatively larger sampling of dwarf galaxies compared to optically-selected surveys. The low H I mass, low luminosity and low surface brightness galaxy populations have, on average, lower Hα/FUV flux ratios than the remaining galaxy populations, consistent with the earlier results of Meurer. The near-identical Hα- and FUV-derived SFRD values arise with the low Hα/FUV flux ratios of some galaxies being offset by enhanced Hα from the brightest and high mass galaxy populations. Our findings confirm the necessity to fully sample the H I mass range for a complete census of local star formation to include lower stellar mass galaxies which dominate the local Universe.

Role of cold isostatic pressing in the formation of the properties of ZrO{sub 2}-base ceramics obtained from ultradisperse powders

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

Akimov, G.Y.; Prokhorov, I.Y.; Gorelik, I.V.

1995-09-01

The physicomechanical properties of ceramics obtained from plasmachemical and sol-gel powders of partially stabilized (3% Y{sub 2}O{sub 3}) zirconia (PSZ) and its compositions with 20% Al{sub 2}O{sub 3} by cold isostatic pressing (CIP) at a pressure of at most 2 GPa and sintering at 1300-1650{degrees}C are investigated. It is established that plasmachemical PSZ exhibits its best properties (K{sub 1c} = 7.8 MPa {center_dot} m{sup 1/2}, a strength of 650 MPa) only after complete disintegration at a CIP of 0.1 GPa and a sintering temperature of 1650{degrees}C, when the material is sintered to a density of 5.5 g/cm{sup 3}. After partialmore » stabilization and CIP at 0.1 GPa the plasmachemical composition of PSZ + 20% Al{sub 2}O{sub 3} is sintered at 1650{degrees}C to a density of 4.7 g/cm{sup 3}, but has K{sub 1c} = 8.5 MPa {center_dot} m{sup 1/2} and a strength of 700 MPa. The deagglomerated sol-gel powder exhibits properties at a level of K{sub 1c} = 12.4 MPa {center_dot} m{sup 1/2} and a strength of 950 MPa at a density above 6.0 g/cm{sup 3} after CIP at 0.3 GPa and sintering at 1450{degrees}C. The latter obviously has the best mechanical properties of all the investigated materials.« less

Tuning the Formations of Metal-Organic Frameworks by Modification of Ratio of Reactant, Acidity of Reaction System, and Use of a Secondary Ligand

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

Gao, Q; Xie, YB; Li, JR

2012-01-01

Four porous coordination networks (PCNs), {[Zn3O(H2O)(3)(adc)(3)]center dot 2(C2H6NH2)center dot 2(DMF)center dot 3(H2O)}(n) (PCN-131), Zn-2(DMA)(2)(adc)(2)]center dot 2(DMA)}(n) (PCN-132), {[Zn3O(DMF)(adc)(3)(4,4'-bpy)]center dot 2(C2H6NH2)center dot S}(n) (PCN-131'), and {[Zn(adc)(4,4'-bpy)(0.5)]center dot S}(n) (PCN-132'), have been synthesized by the assembly of anthrancene-9,10-dicarboxylic acid (H(2)adc) with Zn(II) under different reaction conditions, including modifications of reactant ratio, acidity variations, and the use of a secondary ligand. Single-crystal X-ray diffraction studies reveal that PCN-131, obtained from the dimethylformamide (DMF) solution under acid condition, has a three-dimentional (3D) framework structure with one-dimensional (1D) honeycomb channels. PCN-132 isolated from dimethylacetamide (DMA) solution without adding acid in synthesis is a two-dimensional (2D)more » layer compound. By employing 4,4'-bipyridyl (4,4'-bpy) as a secondary ligand, PCN-131' and PCN-132' were synchronously synthesized as a mixture outcome with more PCN-131' than PCN-132'. In PCN-131', 4,4'-bpy acting as a secondary ligand is arranged inside the honeycomb channel of the 3D PCN-131, resulting in an effective improvement of thermal stability of the network, while in PCN-132', 4,4'-bpy ligands link 2D layers of PCN-132 to form a pillared-layer 3D framework Gas adsorption has been performed for selected materials. The results show that the framework of PCN-131 is thermally unstable after removing the solvent molecules coordinated to their metal sites. While PCN-131' is stable for gas uptake, with an evaluated Langmuir surface area of 199.04 m(2) g(-1), it shows a selective adsorption of CO2 over CH4.« less

Enhancing the Predictive Power of Mutations in the C-Terminus of the KCNQ1-Encoded Kv7.1 Voltage-Gated Potassium Channel.

PubMed

Kapplinger, Jamie D; Tseng, Andrew S; Salisbury, Benjamin A; Tester, David J; Callis, Thomas E; Alders, Marielle; Wilde, Arthur A M; Ackerman, Michael J

2015-04-01

Despite the overrepresentation of Kv7.1 mutations among patients with a robust diagnosis of long QT syndrome (LQTS), a background rate of innocuous Kv7.1 missense variants observed in healthy controls creates ambiguity in the interpretation of LQTS genetic test results. A recent study showed that the probability of pathogenicity for rare missense mutations depends in part on the topological location of the variant in Kv7.1's various structure-function domains. Since the Kv7.1's C-terminus accounts for nearly 50 % of the overall protein and nearly 50 % of the overall background rate of rare variants falls within the C-terminus, further enhancement in mutation calling may provide guidance in distinguishing pathogenic long QT syndrome type 1 (LQT1)-causing mutations from rare non-disease-causing variants in the Kv7.1's C-terminus. Therefore, we have used conservation analysis and a large case-control study to generate topology-based estimative predictive values to aid in interpretation, identifying three regions of high conservation within the Kv7.1's C-terminus which have a high probability of LQT1 pathogenicity.

Hexon-modified recombinant E1-deleted adenoviral vectors as bivalent vaccine carriers for Coxsackievirus A16 and Enterovirus 71.

PubMed

Zhang, Chao; Yang, Yong; Chi, Yudan; Yin, Jieyun; Yan, Lijun; Ku, Zhiqiang; Liu, Qingwei; Huang, Zhong; Zhou, Dongming

2015-09-22

Hand, foot and mouth disease (HFMD) is a major public health concern in Asia; more efficient vaccines against HFMD are urgently required. Adenoviral (Ad) capsids have been used widely for the presentation of foreign antigens to induce specific immune responses in the host. Here, we describe a novel bivalent vaccine for HFMD based on the hexon-modified, E1-deleted chimpanzee adenovirus serotype 68 (AdC68). The novel vaccine candidate was generated by incorporating the neutralising epitope of Coxsackievirus A16 (CA16), PEP71, into hypervariable region 1 (HVR1), and a shortened neutralising epitope of Enterovirus 71 (EV71), sSP70, into HVR2 of the AdC68 hexon. In order to enhance the immunogenicity of EV71, VP1 of EV71 was cloned into the E1-region of the AdC68 vectors. The results demonstrated that these two epitopes were well presented on the virion surface and had high affinity towards specific antibodies, and VP1 of EV71 was also significantly expressed. In pre-clinical mouse models, the hexon-modified AdC68 elicited neutralising antibodies against both CA16 and EV71, which conferred protection to suckling mice against a lethal challenge of CA16 and EV71. In summary, this study demonstrates that the hexon-modified AdC68 may represent a promising bivalent vaccine carrier against EV71 and CA16 and an epitope-display platform for other pathogens. Copyright © 2015 Elsevier Ltd. All rights reserved.

RDTC [Restricted Data Transmission Controller] global variable definitions

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

Grambihler, A.J.; O`Callaghan, P.B.

The purpose of the Restricted Data Transmission Controller (RDTC) is to demonstrate a methodology for transmitting data between computers which have different levels of classification. The RDTC does this by logically filtering the data being transmitted between the two computers. This prototype is set up to filter data from the classified computer so that only numeric data is passed to the unclassified computer. The RDTC allows all data from the unclassified computer to be sent to the classified computer. The classified system is referred to as LUA and the unclassified system is referred to as LUB. 9 tabs.

Quantum confinement effect in 6H-SiC quantum dots observed via plasmon-exciton coupling-induced defect-luminescence quenching

NASA Astrophysics Data System (ADS)

Guo, Xiaoxiao; Zhang, Yumeng; Fan, Baolu; Fan, Jiyang

2017-03-01

The quantum confinement effect is one of the crucial physical effects that discriminate a quantum material from its bulk material. It remains a mystery why the 6H-SiC quantum dots (QDs) do not exhibit an obvious quantum confinement effect. We study the photoluminescence of the coupled colloidal system of SiC QDs and Ag nanoparticles. The experimental result in conjunction with the theoretical calculation reveals that there is strong coupling between the localized electron-hole pair in the SiC QD and the localized surface plasmon in the Ag nanoparticle. It results in resonance energy transfer between them and resultant quenching of the blue surface-defect luminescence of the SiC QDs, leading to uncovering of a hidden near-UV emission band. This study shows that this emission band originates from the interband transition of the 6H-SiC QDs and it exhibits a remarkable quantum confinement effect.

The Coxiella Burnetii type IVB secretion system (T4BSS) component DotA is released/secreted during infection of host cells and during in vitro growth in a T4BSS-dependent manner.

PubMed

Luedtke, Brandon E; Mahapatra, Saugata; Lutter, Erika I; Shaw, Edward I

2017-06-01

Coxiella burnetii is a Gram-negative intracellular pathogen and is the causative agent of the zoonotic disease Q fever. To cause disease, C. burnetii requires a functional type IVB secretion system (T4BSS) to transfer effector proteins required for the establishment and maintenance of a membrane-bound parasitophorous vacuole (PV) and further modulation of host cell process. However, it is not clear how the T4BSS interacts with the PV membrane since neither a secretion pilus nor an extracellular pore forming apparatus has not been described. To address this, we used the acidified citrate cysteine medium (ACCM) along with cell culture infection and immunological techniques to identify the cellular and extracellular localization of T4BSS components. Interestingly, we found that DotA and IcmX were secreted/released in a T4BSS-dependent manner into the ACCM. Analysis of C. burnetii-infected cell lines revealed that DotA colocalized with the host cell marker CD63 (LAMP3) at the PV membrane. In the absence of bacterial protein synthesis, DotA also became depleted from the PV membrane. These data are the first to identify the release/secretion of C. burnetii T4BSS components during axenic growth and the interaction of a T4BSS component with the PV membrane during infection of host cells. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Luminescent high temperature sensor based on the CdSe/ZnS quantum dot thin film

NASA Astrophysics Data System (ADS)

Wang, He-lin; Yang, Ai-jun; Sui, Cheng-hua

2013-11-01

A high temperature sensor based on the multi-parameter temperature dependent characteristic of photoluminescence (PL) of quantum dot (QD) thin film is demonstrated by depositing the CdSe/ZnS core/shell QDs on the SiO2 glass substrates. The variations of the intensity, the peak wavelength and the full width at half maximum (FWHM) of PL spectra with temperature are studied experimentally and theoretically. The results indicate that the peak wavelength of the PL spectra changes linearly with temperature, while the PL intensity and FWHM vary exponentially for the temperature range from 30 °C to 180 °C. Using the obtained temperature dependent optical parameters, the resolution of the designed sensor can reach 0.1 nm/°C.

Structural insights into the roles of the IcmS-IcmW complex in the type IVb secretion system of Legionella pneumophila.

PubMed

Xu, Jianpo; Xu, Dandan; Wan, Muyang; Yin, Li; Wang, Xiaofei; Wu, Lijie; Liu, Yanhua; Liu, Xiaoyun; Zhou, Yan; Zhu, Yongqun

2017-12-19

The type IVb secretion system (T4BSS) of Legionella pneumophila is a multiple-component apparatus that delivers ∼300 virulent effector proteins into host cells. The injected effectors modulate host cellular processes to promote bacterial infection and proliferation. IcmS and IcmW are two conserved small, acidic adaptor proteins that form a binary complex to interact with many effectors and facilitate their translocation. IcmS and IcmW can also interact with DotL, an ATPase of the type IV coupling protein complex (T4CP). However, how IcmS-IcmW recognizes effectors, and what the roles of IcmS-IcmW are in T4BSSs are unclear. In this study, we found that IcmS and IcmW form a 1:1 heterodimeric complex to bind effector substrates. Both IcmS and IcmW adopt new structural folds and have no structural similarities with known effector chaperones. IcmS has a compact global structure with an α/β fold, while IcmW adopts a fully α-folded, relatively loose architecture. IcmS stabilizes IcmW by binding to its two C-terminal α-helices. Photocrosslinking assays revealed that the IcmS-IcmW complex binds its cognate effectors via an extended hydrophobic surface, which can also interact with the C terminus of DotL. A crystal structure of the DotL-IcmS-IcmW complex reveals extensive and highly stable interactions between DotL and IcmS-IcmW. Moreover, IcmS-IcmW recruits LvgA to DotL and assembles a unique T4CP. These data suggest that IcmS-IcmW also functions as an inseparable integral component of the DotL-T4CP complex in the bacterial inner membrane. This study provides molecular insights into the dual roles of the IcmS-IcmW complex in T4BSSs.

Minimization of material inter-diffusion for thermally stable quaternary-capped InAs quantum dot via strain modification

NASA Astrophysics Data System (ADS)

Ghadi, Hemant; Sehara, Navneet; Murkute, Punam; Chakrabarti, Subhananda

2017-05-01

In this study, a theoretical model is developed for investigating the effect of thermal annealing on a single-layer quaternary-capped (In0.21Al0.21Ga0.58As) InAs quantum dot heterostructure (sample A) and compared to a conventional GaAs-capped sample (sample B). Strain, an interfacial property, aids in dot formation; however, it hinders interdiffusion (up to 650 °C), rendering thermal stability to heterostructures. Three diffusing species In/Al/Ga intermix because of the concentration gradient and temperature variation, which is modeled by Fick's law of diffusion. Ground-state energy for both carriers (electron and holes) is calculated by the Schrodinger equation at different annealing temperatures, incorporating strain computed by the concentration-dependent model. Change in activation energy due to strain decreases particle movement, thereby resulting in thermally stable structures at low annealing temperatures. At low temperature, the conduction band near the dot edge slightly decreases, attributed to the comparatively high strain. Calculated results are consistent with the experimental blue-shift i.e. towards lower wavelength of photoluminescence peak on the same sample with increasing annealing temperatures. Cross-sectional transmission microscopy (TEM) images substantiate the existence of dot till 800 °C for sample (A). With increasing annealing temperature, interdiffusion and dot sublimation are observed in XTEM images of samples A and B. Strain calculated from high-resolution X-ray diffraction (HRXRD) peaks and its decline with increasing temperature are in agreement with that calculated by the model. For highlighting the benefits of quaternary capping, InAlGaAs capping is theoretically and experimentally compared to GaAs capping. Concentration-dependent strain energy is calculated at every point and is further used for computing material interdiffusion, band profiles, and photoluminescence peak wavelength, which can provide better insights into strain energy behavior with temperature and help in the better understanding of thermal annealing.

Global Well-Posedness and Temporal Decay Estimates for the 3D Nematic Liquid Crystal Flows

NASA Astrophysics Data System (ADS)

Liu, Qiao

2018-03-01

In this paper, we investigate global well-posedness and large time behavior of the Cauchy problem for the 3D incompressible nematic liquid crystal flows. By using the advantage of suitable weighted function, we show that for any initial data (u0,d0-\\overline{d}0) in critical Besov spaces \\dot{B}^{3/p-1}_{p,1}(R3)× \\dot{B}^{3/q}_{q,1}(R3) with 1< p, q<∞ and -\\inf {1/3,1/2p}≤1/q-1/p≤1/3 , if the initial orientation d0-\\overline{d}0 and a certain nonlinear function of initial velocity u0 are small enough, then there exists a global-in-time solution to the nematic liquid crystal flows. We also give an example of initial velocity satisfying that nonlinear smallness condition, but each component of its norm may be arbitrarily large. Moreover, if we further assume that (u0,d0-\\overline{d}0)\\in \\dot{B}^{-s}_{r,∞}(R3)× \\dot{B}^{-s+1}_{r,∞}(R3) with 1

X-ray Crystal Structures of the Type IVb Secretion System DotB ATPases.

PubMed

Prevost, Marie S; Waksman, Gabriel

2018-05-17

Human infections by the intracellular bacterial pathogen Legionella pneumophila result in a severe form of pneumonia, the Legionnaire's disease. L. pneumophila utilises a type IVb secretion (T4bS) system termed "dot/icm" to secrete protein effectors to the host cytoplasm. The dot/icm system is powered at least in part by a functionally critical AAA+ ATPase, a protein called DotB, thought to belong to the VirB11 family of proteins. Here we present the crystal structure of DotB at 3.19 Å resolution, in its hexameric form. We observe that DotB is in fact a structural intermediate between VirB11 and PilT family proteins, with a PAS-like N-terminal domain coupled to a RecA-like C-terminal domain. It also shares critical structural elements only found in PilT. The structure also reveals two conformers, termed α and β, with an αβαβαβ configuration. The existence of α and β conformers in this class of proteins was confirmed by solving the structure of DotB from another bacterial pathogen, Yersinia, where, intriguingly, we observed an ααβααβ configuration. The two conformers co-exist regardless of the nucleotide-bound states of the proteins. Our investigation therefore reveals that these ATPases can adopt a wider range of conformational states than was known before, shedding new light on the extraordinary spectrum of conformations these ATPases can access to carry out their function. Overall, the structure of DotB provides a template for further rational drug-design to develop more specific antibiotics to tackle Legionnaire's disease. This article is protected by copyright. All rights reserved. © 2018 The Protein Society.

Pre-discovery Observations and Orbit of Comet C/2017 K2 (PANSTARRS)

NASA Astrophysics Data System (ADS)

Hui, Man-To; Jewitt, David; Clark, David

2018-01-01

We present a study of comet C/2017 K2 (PANSTARRS) using pre-discovery archival data taken from 2013 to 2017. Our measurements show that the comet has been marginally increasing in activity since at least 2013 May (heliocentric distance of {r}{{H}}=23.7 {au} pre-perihelion). We estimate the mass-loss rate during the period 2013–2017 as \\overline{\\dot{M}}≈ (2.4+/- 1.1)× {10}2 kg s‑1, which requires a minimum active surface area of ∼10–102 km2 for sublimation of supervolatiles such as CO and CO2, by assuming a nominal cometary albedo {p}V=0.04+/- 0.02. The corresponding lower limit to the nucleus radius is a few kilometers. Our Monte Carlo dust simulations show that dust grains in the coma are ≳ 0.5 {mm} in radius, with ejection speeds from ∼1 to 3 m s‑1, and have been emitted in a protracted manner since 2013, confirming estimates by Jewitt et al. The current heliocentric orbit is hyperbolic. Our N-body backward dynamical integration of the orbit suggests that the comet is most likely (with a probability of ∼98%) from the Oort spike. The calculated median reciprocal of the semimajor axis 1 Myr ago was {a}med}-1=(3.61+/- 1.71)× {10}-5 au‑1 (in a reference system centered on the solar-system barycenter).

Transverse momentum dependent two-pion Bose-Einstein correlations in Au + Au collisions at 11.6 A (center-dot) GeV/c

NASA Technical Reports Server (NTRS)

Lee, J. H.

1998-01-01

Bose-Einstein correlations of (pi)(sup +)(pi)(sup +) and (pi)(sup -) (pi)(sup -) pairs collected by the BNL-E866 Forward Spectrometer in 11.6 A(center-dot)GeV/c Au + Au collisions have been measured. The data were analyzed using three-dimensional correlation functions parameterized by the Yano-Koonin-Potgoretskii and Bertsch-Pratt formalism to study transverse momentum dependent source parameters. Rapid decreases of longitudinal source radii and slower decreases in the transverse parameters with increasing transverse momentum were observed, which suggests a strong longitudinal and some transverse expansion. A freeze-out time (tau)(sub 0) was derived as 4.5--5 fm/c, under the assumption of the freeze-out temperature T = 130 MeV, and the duration of emission was found to be (delta)(tau) (approx) 2--4 fm/c.

Preparation of nitrogen-doped carbon using graphene Quantum dots-chitosan as the precursor and its supercapacitive behaviors.

PubMed

Tan, Wensheng; Fu, Renjun; Ji, Hong; Kong, Yong; Xu, Yueguo; Qin, Yong

2018-06-01

Nitrogen-doped carbon (N-C) is pyrolytically prepared by using the nanocomposites of graphene Quantum dots (GQDs) and chitosan (CS) as the precursor. Due to the existence of GQDs nanofiller, the three-dimensional (3D) interconnected frameworks of CS are well preserved after the pyrolysis treatment; meanwhile, CS in the nanocomposites functions as nitrogen source for the N-C. The obtained N-C exhibits a considerable specific capacitance (545Fg -1 at 1Ag -1 ), high rate capability and excellent cyclic stability (88.9% capacitance retention after 5000cycles at 10Ag -1 ) when it is used as the electrode materials in supercapacitors. The well-preserved 3D frameworks and N-doping are believed to be responsible for the excellent supercapacitive behaviors of the N-C. Copyright © 2018 Elsevier B.V. All rights reserved.

Photovoltaic Conversion Enhancement of a Carbon Quantum Dots/p-Type CuAlO2/n-Type ZnO Photoelectric Device.

PubMed

Pan, Jiaqi; Sheng, Yingzhuo; Zhang, Jingxiang; Huang, Peng; Zhang, Xin; Feng, Boxue

2015-04-22

Carbon quantum dots (C QDs)/p-type CuAlO2/n-type ZnO photoelectric bilayer film composites were prepared by a simple route, through which ZnO films were sputtered on crystal quartz substrates and CuAlO2 films were prepared by sol-gel on ZnO films and then these bilayer films were composited with C QDs on their surface. The characterization results indicated that C QDs were well combined with the surface of the CuAlO2 films. The photovoltage and photocurrent of these bilayer film composites were investigated under illumination and darkness switching, which demonstrated to be significantly enhanced compared with those of the CuAlO2/ZnO bilayer films. Through analysis, this enhancement of the photoconductivity was mainly attributed to C QDs with unique up-converted photoluminescence behavior.

Colossal photo-conductive gain in low temperature processed TiO2 films and their application in quantum dot solar cells

NASA Astrophysics Data System (ADS)

Mandal, Debranjan; Goswami, Prasenjit N.; Rath, Arup K.

2017-03-01

Colloidal quantum dot (QD) solar cells have seen remarkable progress in recent past to reach the certified efficiency of 10.6%. Anatase titanium oxide (TiO2) is a widely studied n-type widow layer for the collection of photogenerated electrons in QD solar cells. Requirement of high temperature (˜500 °C) processing steps proved to be disadvantageous for its applications in flexible solar cells and roll to roll processing, and it also has adverse commercial implications. Here, we report that solar light exposure to low temperature processed (80 °C-150 °C) TiO2 and niobium doped TiO2 films leads to unprecedented enhancement in their electron densities and electron mobilities, which enables them to be used as efficient n-type layers in quantum dot solar cells. Such photoinduced high conducting states in these films show gradual decay over hours after the light bias is taken off and can be retrieved under solar illumination. On the contrary, TiO2 films processed at 500 °C show marginal photo induced enhancements in their characteristics. In bilayer configuration with PbS QDs, photovoltaic devices based on low temperature processed TiO2 films show improved performance over high temperature processed TiO2 films. The stability of photovoltaic devices also improved in low temperature processed TiO2 films under ambient working conditions.

Amine templating effect absent in uranyl sulfates synthesized with 1,4-n-butyldiamine

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

Jouffret, Laurent J., E-mail: ljouffret@nd.edu; Wylie, Ernest M.; Burns, Peter C.

2013-01-15

Two new uranyl sulfates, (C{sub 4}H{sub 14}N{sub 2})[(UO{sub 2}){sub 2}(SO{sub 4}){sub 3}(H{sub 2}O)]{center_dot}2H{sub 2}O (NDUS2) and (C{sub 4}H{sub 14}N{sub 2})[(UO{sub 2})(SO{sub 4}){sub 2}(H{sub 2}O)]{center_dot}2H{sub 2}O (NDUS3), were synthesized and their crystal structures determined. NDUS2 was obtained in highly acidic media heat-treated at 373 K and subsequently maintained at 278 K until crystals formed after two months. NDUS3 results from the degradation of NDUS2 over the course of a few days. NDUS2 and NDUS3 crystallize in the monoclinic space group P2{sub 1}/n, a=10.9075(4) A, b=10.4513(4) A, c=17.7881(7) A, {beta}=97.908(2) Degree-Sign , V=2008.52(13) A{sup 3}, Z=4, at 140 K and a=8.8570(4) A,more » b=7.3299(3) A, c=20.4260(9) A, {beta}=95.140(2) Degree-Sign , V=1320.74(10) A{sup 3}, Z=4, at 140 K, respectively. The compounds contain interlayer 1,4-n-butyldiammonium cations that charge-balance the anionic structural units. - Graphical abstract: Amine templating effect absent in uranyl sulfates synthesized with 1,4-diaminobutane, as shown by the synthesis of two new uranyl sulfates, (C{sub 4}H{sub 14}N{sub 2})[(UO{sub 2}){sub 2}(SO{sub 4}){sub 3}(H{sub 2}O)]{center_dot}2H{sub 2}O (NDUS2) and (C{sub 4}H{sub 14}N{sub 2})[(UO{sub 2})(SO{sub 4}){sub 2}(H{sub 2}O)]{center_dot}2H{sub 2}O (NDUS3). Highlights: Black-Right-Pointing-Pointer Two layered uranyl sulfates were synthesized. Black-Right-Pointing-Pointer Amine molecules are located in the interlayers of the compounds. Black-Right-Pointing-Pointer No templating effect of the amine was observed. Black-Right-Pointing-Pointer Amine molecules are only charge balancing cations in the structures.« less

Lifting of Spin Blockade by Charged Impurities in Si-MOS Double Quantum Dot Devices

NASA Astrophysics Data System (ADS)

King, Cameron; Schoenfield, Joshua; Calderón, M. J.; Koiller, Belita; Saraiva, André; Hu, Xuedong; Jiang, Hong-Wen; Friesen, Mark; Coppersmith, S. N.

Fabricating quantum dots in silicon metal-oxide-semiconductor (MOS) for quantum information processing applications is attractive because of the long spin coherence times in silicon and the potential for leveraging the massive investments that have been made for scaling of the technology for classical electronics. One obstacle that has impeded the development of electrically gated MOS singlet-triplet qubits is the lack of observed spin blockade, where the tunneling of a second electron into a dot is fast when the two-electron state is a singlet and slow when the two-electron state is a triplet, even in samples with large singlet-triplet energy splittings. We show that this is a commonly exhibited problem in MOS double quantum dots, and present evidence that the cause is stray positive charges in the oxide layer inducing accidental dots near the device's active region that allow spin blockade lifting. This work was supported by ARO (W911NF-12-1-0607), NSF (IIA-1132804), the Department of Defense under Contract No. H98230-15-C 0453, ARO (W911NF-14-1-0346), NSF (OISE-1132804), ONR (N00014-15-1-0029), and ARO (W911NF-12-R-0012).

Simple Identification of Human Taenia Species by Multiplex Loop-Mediated Isothermal Amplification in Combination with Dot Enzyme-Linked Immunosorbent Assay

PubMed Central

Nkouawa, Agathe; Sako, Yasuhito; Okamoto, Munehiro; Ito, Akira

2016-01-01

For differential detection of Taenia solium, Taenia saginata, and Taenia asiatica, loop-mediated isothermal amplification (LAMP) assay targeting the cytochrome c oxidase subunit 1 gene has been recently developed and shown to be sensitive, specific, and effective. However, to achieve differential identification, one specimen requires three reaction mixtures containing a primer set of each Taenia species separately, which is complex and time consuming and increases the risk of cross-contamination. In this study, we developed a simple differential identification of human Taenia species using multiplex LAMP (mLAMP) in combination with dot enzyme-linked immunosorbent assay (dot-ELISA). Forward inner primers of T. solium, T. saginata, and T. asiatica labeled with fluorescein isothiocyanate (FITC), digoxigenin (DIG), and tetramethylrhodamine (TAMRA), respectively, and biotin-labeled backward inner primers were used in mLAMP. The mLAMP assay succeeded in specific amplification of each respective target gene in a single tube. Furthermore, the mLAMP product from each species was easily distinguished by dot-ELISA with an antibody specific for FITC, DIG, or TAMRA. The mLAMP assay in combination with dot-ELISA will make identification of human Taenia species simpler, easier, and more practical. PMID:27044566

TERRA and the histone methyltransferase Dot1 cooperate to regulate senescence in budding yeast

PubMed Central

Wanat, Jennifer J.; Logsdon, Glennis A.; Driskill, Jordan H.; Deng, Zhong; Lieberman, Paul M.

2018-01-01

The events underlying senescence induced by critical telomere shortening are not fully understood. Here we provide evidence that TERRA, a non-coding RNA transcribed from subtelomeres, contributes to senescence in yeast lacking telomerase (tlc1Δ). Levels of TERRA expressed from multiple telomere ends appear elevated at senescence, and expression of an artificial RNA complementary to TERRA (anti-TERRA) binds TERRA in vivo and delays senescence. Anti-TERRA acts independently from several other mechanisms known to delay senescence, including those elicited by deletions of EXO1, TEL1, SAS2, and genes encoding RNase H enzymes. Further, it acts independently of the senescence delay provided by RAD52-dependent recombination. However, anti-TERRA delays senescence in a fashion epistatic to inactivation of the conserved histone methyltransferase Dot1. Dot1 associates with TERRA, and anti-TERRA disrupts this interaction in vitro and in vivo. Surprisingly, the anti-TERRA delay is independent of the C-terminal methyltransferase domain of Dot1 and instead requires only its N-terminus, which was previously found to facilitate release of telomeres from the nuclear periphery. Together, these data suggest that TERRA and Dot1 cooperate to drive senescence. PMID:29649255

The relation between disparity and velocity signals of rigidly moving objects constrains depth order perception.

PubMed

Di Luca, Massimiliano; Domini, Fulvio; Caudek, Corrado

2007-05-01

In two experiments, observers were asked to judge the relative depth of a probe and one or two flanker dots. In Experiment 1, we found that such judgments were influenced by the properties of adjacent image regions, that is, by the amount of angular rotation of a surrounding cloud of dots. In Experiment 2, we found that the properties of the adjacent image regions affected the precision of the observers' judgments. With only the probe and the flanker dots presented in isolation, the precision of observers' judgments was much lower than when probe and the flanker dots were surrounded by a rigidly-connected cloud of dots. Conversely, a non-rigid rotation of the surrounding dots was detrimental to the precision of visual performance. These data can be accounted for by the Intrinsic Constraint model [Domini, F., Caudek, C., & Tassinari, H. (2006). Stereo and motion information are not independently processed by the visual system. Vision Research, 46, 1707-1723], which incorporates the mutual constraints relating disparity and motion signals. The present investigation does not show that the rigidity constraint affects the visual interpretation of motion information alone. Rather, our results show that perceptual performance is affected by the linear relation between disparity and velocity signals, when both depth-cues are present and the distal object is, in fact, rigid.

Optically Generated 2-Dimensional Photonic Cluster State from Coupled Quantum Dots

DTIC Science & Technology

2010-03-12

coupled quantum dots 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR( S ) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT...NUMBER 7. PERFORMING ORGANIZATION NAME( S ) AND ADDRESS(ES) Naval Research Laboratory,,Washington,DC,20375 8. PERFORMING ORGANIZATION REPORT NUMBER...9. SPONSORING/MONITORING AGENCY NAME( S ) AND ADDRESS(ES) 10. SPONSOR/MONITOR’S ACRONYM( S ) 11. SPONSOR/MONITOR’S REPORT NUMBER( S ) 12. DISTRIBUTION

Leveraging Crystal Anisotropy for Deterministic Growth of InAs Quantum Dots with Narrow Optical Linewidths

DTIC Science & Technology

2013-08-29

similar layer thicknesses. This offset indicates that the electric field profile of our Schottky diode is different than for unpatterned samples, implying...sacrificing uniformity by further optimizing the substrate Figure 3. (a) Schematic of the Schottky diode heterostructure, indicating the patterned substrate...and negative (X−) trions are indicated . (c) Distribution of linewidths for 80 PL lines from dots grown in high density arrays such as those in Figure 2b

Inhalation Toxicology. 11. The Effect of Elevated Temperature on Carbon Monoxide Toxicity

DTIC Science & Technology

1990-12-01

DOT/FAA/AM-90/16 Inhalation Toxicology : XI. The Effect of Elevated Temperature on Carbon Office of Aviation Medicine Washington, D.C. 20591 M onoxide...Accession No. 3. Recipient’s Catalog No. DOT/FAA/AM-90/16 4. Title and Subtitie S. Report Date INHALATION TOXICOLOGY : XI. THE EFFECT OF ELEVATED December...Statement Combustion toxicology , carbon monoxide, This document is available to the public heat, thermal effects, time-to- through the National Technical

Aircraft Wake Vortices: An Assessment of the Current Situation

DTIC Science & Technology

1991-01-01

1979 , DOT/TSC, Cambridge, MA. 36. Burnham, D.C., "Chicago Monostatic Acoustic Vortex Sensing System, Vol. I : Data Collection and Reduction," FAA-RD-79...April 1979 , DOT/TSC, Cambridge, MA. 45. Hallock, J.N., "Vortex Advisory System Safety Analysis; Vol. I : Analytical Model," FAA-RD-78-68. I , September...Industry Representatives," March 1979 , Economics & Science Planning Inc., Washington, DC. 106. Hallock, J.N., "Vortex Advisory System, Vol. I : Effectiveness

Microwave-Driven Coherent Operation of a Semiconductor Quantum Dot Charge Qubit

DTIC Science & Technology

2015-02-16

indicating that understanding high frequency charge noise as well as charge relaxation at the sweet spot will be important for further development. The...Microwave-driven coherent operation of a semiconductor quantum dot charge qubit Dohun Kim,1 D. R. Ward,1 C. B. Simmons,1 John King Gamble,2 Robin...University of Wisconsin-Madison, Madison, WI 53706, USA A most intuitive realization of a qubit is a sin- gle electron charge sitting at two well -defined

Characterization of the R162W Kir7.1 mutation associated with snowflake vitreoretinopathy

PubMed Central

Zhang, Wei; Zhang, Xiaoming; Wang, Hui; Sharma, Anil K.; Edwards, Albert O.

2013-01-01

KCNJ13 encodes Kir7.1, an inwardly rectifying K+ channel that is expressed in multiple ion-transporting epithelia. A mutation in KCNJ13 resulting in an arginine-to-tryptophan change at residue 162 (R162W) of Kir7.1 was associated with snowflake vitreoretinal degeneration, an inherited autosomal-dominant disease characterized by vitreous degeneration and mild retinal degeneration. We used the Xenopus laevis oocyte expression system to assess the functional properties of the R162W (mutant) Kir7.1 channel and determine how wild-type (WT) Kir7.1 is affected by the presence of the mutant subunit. Recordings obtained via the two-electrode voltage-clamp technique revealed that injection of oocytes with mutant Kir7.1 cRNA resulted in currents and cation selectivity that were indistinguishable from those in water-injected oocytes, suggesting that the mutant protein does not form functional channels in the plasma membrane. Coinjection of oocytes with equal amounts of mutant and WT Kir7.1 cRNAs resulted in inward K+ and Rb+ currents with amplitudes that were ∼17% of those in oocytes injected with WT Kir7.1 cRNA alone, demonstrating a dominant-negative effect of the mutant subunit. Similar to oocytes injected with WT Kir7.1 cRNA alone, coinjected oocytes exhibited inwardly rectifying Rb+ currents that were more than seven times larger than K+ currents, indicating that mutant subunits did not alter Kir7.1 channel selectivity. Immunostaining of Xenopus oocytes or Madin-Darby canine kidney cells expressing mutant or WT Kir7.1 demonstrated distribution of both proteins primarily in the plasma membrane. Our data suggest that the R162W mutation suppresses Kir7.1 channel activity, possibly by negatively impacting gating by membrane phosphadidylinositol 4,5-bisphosphate. PMID:23255580

Biocide immobilized OMMT-carbon dot reduced Cu2O nanohybrid/hyperbranched epoxy nanocomposites: Mechanical, thermal, antimicrobial and optical properties.

PubMed

De, Bibekananda; Gupta, Kuldeep; Mandal, Manabendra; Karak, Niranjan

2015-11-01

The present work demonstrated a transparent thermosetting nanocomposite with antimicrobial and photoluminescence attributes. The nanocomposites are fabricated by incorporation of different wt.% (1, 2 and 3) of a biocide immobilized OMMT-carbon dot reduced Cu2O nanohybrid (MITH-NH) in the hyperbranched epoxy matrix. MITH-NH is obtained by immobilization of 2-methyl-4-isothiazolin-3-one hydrochloride (MITH) at room temperature using sonication on OMMT-carbon dot reduced Cu2O nanohybid. The nanohybrid is prepared by reduction of cupric acetate using carbon dot as the reducing agent in the presence of OMMT at 70°C. The significant improvements in tensile strength (~2 fold), elongation at break (3 fold), toughness (4 fold) and initial thermal degradation temperature (30°C) of the pristine hyperbranched epoxy system are achieved by incorporation of 3wt.% of MITH-NH in it. The nanocomposites exhibit strong antimicrobial activity against Staphylococcus aureus, Bacillus subtilis, Klebsiella pneumoniae and Pseudomonas aeruginosa bacteria and Candida albicans, a fungus. The nanocomposite also shows significant activity against biofilm formation compared to the pristine thermoset. Further, the nanocomposite films emit different colors on exposure of different wavelengths of UV light. The properties of these nanocomposites are also compared with the same nanohybrid without OMMT. Copyright © 2015. Published by Elsevier B.V.

Microwave formation and photoluminescence mechanisms of multi-states nitrogen doped carbon dots

NASA Astrophysics Data System (ADS)

He, Guili; Shu, Mengjun; Yang, Zhi; Ma, Yujie; Huang, Da; Xu, Shusheng; Wang, Yanfang; Hu, Nantao; Zhang, Yafei; Xu, Lin

2017-11-01

In recent years, carbon dots (CDs) have attracted much attention in the material field because of their remarkable performance in various aspects. Therefore, the exploration of complex and variable photoluminescence mechanisms shows great significance. Herein, we present a systematic study on the correlation between the formation process and photoluminescence mechanisms through the characterization and analysis of three states of nitrogen doped carbon dots (N-CDs) obtained by microwave irradiation. At low temperature of 160 °C, the small organic molecule polymer nanodots whose photoluminescence center is molecule state are obtained with superior quantum yield of about 51.61%. Increasing the reaction temperature up to 200 °C, the intermediate transition products named carbon nanodots begin to appear. Prolonging the holding time, the typical carbon quantum dots with a special stable optical properties are finally generated, and their most photoluminescence arises from the carbon cores which are gained through the polymerization, dehydration, carbonation of organic fluorescent molecules. Furthermore, N-CDs have been applied in metal ions detection as well as animal and plant cell fluorescence imaging owing to their excellent water solubility and low cytotoxicity. Our exploration provides the theoretical basis for synthesis of CDs with different properties and purposes. In the near future, more high-quality CDs will be developed in order to better benefit the various fields of mankind.

Lithium Batteries and Supercapacitors Capable of Operating at Low Temperatures for Planetary Exploration

NASA Technical Reports Server (NTRS)

Smart, M. C.; Ratnakumar, B. V.; West, W. C.; Brandon, E. J.

2012-01-01

Demonstrated improved performance with wide operating temperature electrolytes containing ester co - solvents (i.e., methyl propionate and ethyl butyrate) in a number of prototype cells: center dot Successfully scaled up low temperature technology to 12 Ah size prismatic Li - ion cells (Quallion, LCC), and demonstrated good performance down to - 60 o C. center dot Demonstrated wide operating temperature range performance ( - 60 o to +60 o C) in A123 Systems LiFePO 4 - based lithium - ion cells containing methyl butyrate - based low temperature electrolytes. These systems were also demonstrated to have excellent cycle life performance at ambient temperatures, as well as the ability to be cycled up to high temperatures.

Statistics on Aircraft Gas Turbine Engine Rotor Failures that Occurred in U.S. Commercial Aviation During 1981.

DTIC Science & Technology

1987-03-01

1 0 0 1 1.7 0 0 1.7 TFE731 4 0.001 0 0 0 0 0 0 0 0 ENG. TYPE TOTAL 6974 17.772 53 12 37 102 2.9 0.7 2.1 5.7 TURBOPROP PT6A 682 1.27 3 1 3 7 2.4 0.8...AGL- 60 (2) ANM- 60 (2) C-I FAA, Chief, Civil Aviation Assistance Group (1) Al Astorga (1) Madrid, Spain Federal Aviation c/o American Embassy...60201 Washington, DC 20591 DOT/Federal Aviation Administration (5) DOT/FAA Northwest Mountain Region (2) AEU-500 ANM- 60 American Embassy 17900 Pacific

Nucleosynthesis inside Supernova-Driven Supercritical Accretion Disks

NASA Astrophysics Data System (ADS)

Fujimoto, Shin-Ichirou; Arai, Kenzo; Matsuba, Ryuichi; Hashimoto, Masa-Aki; Koike, Osamu; Mineshige, Shin

2001-06-01

We have investigated nucleosynthesis in a supercritical accretion disk around a compact object of 1.4Msolar, using the self-similar solution of an optically thick advection dominated flow. Supercritical accretion is expected to occur in a supernova with fallback material accreting onto a new-born compact object. It has been found that appreciable nuclear reactions take place even for a reasonable value of the viscosity parameter, αvissimeq 0.01, when the accretion rate dot{m}=dot{M}c2/(16LEdd) > 105, where LEdd is the Eddington luminosity. If dot{m} ge 4 × 106, all heavy elements are destroyed to 4He through photodisintegrations at the inner part of the disk. Even 4He is also disintegrated to protons and neutrons near the inner edge when dot{m} ge 2 × 107. If the fallback matter of the supernova explosion has the composition of a helium-rich layer of the progenitor, a considerable amount of 44Ti could be ejected via a jet from the disk.

Superoxide scavenging activity of pirfenidone-iron complex

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

Mitani, Yoshihiro; Sato, Keizo; Muramoto, Yosuke

Pirfenidone (PFD) is focused on a new anti-fibrotic drug, which can minimize lung fibrosis etc. We evaluated the superoxide (O{sub 2}{sup {center_dot}}{sup -}) scavenging activities of PFD and the PFD-iron complex by electron spin resonance (ESR) spectroscopy, luminol-dependent chemiluminescence assay, and cytochrome c reduction assay. Firstly, we confirmed that the PFD-iron complex was formed by mixing iron chloride with threefold molar PFD, and the complex was stable in distillated water and ethanol. Secondary, the PFD-iron complex reduced the amount of O{sub 2}{sup {center_dot}}{sup -} produced by xanthine oxidase/hypoxanthine without inhibiting the enzyme activity. Thirdly, it also reduced the amount ofmore » O{sub 2}{sup {center_dot}}{sup -} released from phorbor ester-stimulated human neutrophils. PFD alone showed few such effects. These results suggest the possibility that the O{sub 2}{sup {center_dot}}{sup -} scavenging effect of the PFD-iron complex contributes to the anti-fibrotic action of PFD used for treating idiopathic pulmonary fibrosis.« less

Experimental Studies of Quasi-Adiabatic Quantum-dot Cellular Automata

NASA Astrophysics Data System (ADS)

Orlov, Alexei; Amlani, Islamshah; Kummamuru, Ravi; Toth, Geza; Bernstein, Gary; Lent, Craig; Snider, Gregory

2000-03-01

The computational approach known as Quantum-dot Cellular Automata (QCA) uses interacting quantum dots to encode and process binary information. The first realization of a functioning QCA cell has already been reported. Recently, quasi-adiabatic switching of QCA in a metal dot system near the instantaneous ground state was proposed [1]. The advantage if this approach is that it allows both logic and addressable memory to be implemented within the QCA framework. We report on the fabrication and measurement of such a device in the Al-AlOx tunnel junction system. This basic building block consists of three metal islands connected in series by tunnel junctions, where an electron can be moved between islands by means of electrostatic perturbation on either control electrodes or adjacent cells. The cell can have three operational modes, i.e. active, locked and null, which provide a solution for ground state computing that is not susceptible to metastable states. [1] G. Toth and C. S. Lent, J. appl. Phys. 85 5, 2977-2984, 1999.

Investigation of structural, morphological and opto-electronic properties of CdS quantum dot thin film

NASA Astrophysics Data System (ADS)

Ibrahim Mohammed S., M.; Gubari, Ghamdan M. M.; Huse, Nanasaheb P.; Dive, Avinash S.; Sharma, Ramphal

2018-05-01

We have successfully deposited CdS quantum dot thin film on the glass substrate by simple and economic chemical bath deposition method at ˜50 ˚C. The X-ray diffraction study confirms the formation of CdS when compared with standard JCPDS data with average crystallite size ˜3 nm. The morphology of the film was studied by FE-SEM, which suggests the homogeneous and uniform deposition of the CdS material over the entire glass substrate with a porous structure. From UV absorption spectra we observed that the sample exhibited a band edge near ˜400 nm with a slight deviation with the presence of excitonic peak for the sample. The presence of excitonic peak may be attributed to the formation of quantum dots. The calculated band gap energy of CdS quantum dot thin film was found to be ˜3.136 eV. The thin film further characterized to study electrical parameters and the sample show a drastic increase in current after light illumination.

Fluorescent Nanoparticles from Several Commercial Beverages: Their Properties and Potential Application for Bioimaging.

PubMed

Liao, Han; Jiang, Chengkun; Liu, Wenqiang; Vera, Juan Manuel; Seni, Oscar David; Demera, Kevin; Yu, Chenxu; Tan, Mingqian

2015-09-30

The presence of nanoparticles in beverages has raised great concern in terms of potential impacts to consumer health. Herein, carbon dots in beverages kvass, pony malta, pilsner beer, Vivant Storm, and Profit were identified. They were shown to have a strong fluorescence under the excitation of ultraviolet light. The emission peaks shift to longer wavelengths accompanied by a remarkable fluorescence intensity decrease. The carbon dots are in the nanosized range and roughly spherical in appearance. Elemental analysis by X-ray photoelectron spectroscopy demonstrated the composition of Kvass carbon dots to be C 83.17%, O 13.83%, and N 3.00%. No cytotoxicity was found at concentrations up to 20 mg/mL for human tongue squamous carcinoma cells, and they can be directly applied in both carcinoma and onion epidermal cell imaging. This work represents the first report of the carbon dots present in beverages, providing valuable insights into these nanoparticles for future biological imaging.

Numerical Simulation of Hot Accretion Flows. III. Revisiting Wind Properties Using the Trajectory Approach

NASA Astrophysics Data System (ADS)

Yuan, Feng; Gan, Zhaoming; Narayan, Ramesh; Sadowski, Aleksander; Bu, Defu; Bai, Xue-Ning

2015-05-01

Previous MHD simulations have shown that wind must exist in black hole hot accretion flows. In this paper, we continue our study by investigating the detailed properties of wind and the mechanism of wind production. For this aim, we make use of a 3D general relativistic MHD simulation of hot accretion flows around a Schwarzschild black hole. To distinguish real wind from turbulent outflows, we track the trajectories of the virtual Lagrangian particles from simulation data. We find two types of real outflows, i.e., a jet and a wind. The mass flux of wind is very significant, and its radial profile can be described by {{\\dot{M}}wind}≈ {{\\dot{M}}BH}≤ft( r/20 {{r}s} \\right), with {{\\dot{M}}BH} being the mass accretion rate at the black hole horizon and rs being the Schwarzschild radius. The poloidal wind speed almost remains constant once they are produced, but the flux-weighted wind speed roughly follows {{v}p,wind}(r)≈ 0.25{{v}k}(r), with vk(r) being the Keplerian speed at radius r. The mass flux of the jet is much lower, but the speed is much higher, {{v}p,jet} ˜ (0.3-0.4)c. Consequently, both the energy and momentum fluxes of the wind are much larger than those of the jet. The wind is produced and accelerated primarily by the combination of centrifugal force and magnetic pressure gradient, while the jet is mainly accelerated by the magnetic pressure gradient. Finally, we find that the wind production efficiency {{ɛ }wind}\\equiv {{\\dot{E}}wind}/{{\\dot{M}}BH}{{c}2}˜ 1/1000 is in good agreement with the value required from large-scale galaxy simulations with active galactic nucleus feedback.

Highly sensitive serological methods for detecting tomato yellow leaf curl virus in tomato plants and whiteflies.

PubMed

Xie, Yan; Jiao, Xiaoyang; Zhou, Xueping; Liu, Huan; Ni, Yuequn; Wu, Jianxiang

2013-05-06

Tomato yellow leaf curl virus (TYLCV) is a member of the genus Begomovirus in the family Geminiviridae, which causes severe losses in tomato production in tropic and subtropic regions. The purified TYLCV virions were used as the immunogen to produce monoclonal antibodies (MAbs) using the hybridoma technology. MAb-based dot enzyme-linked immunosorbent assay (dot-ELISA) and direct tissue blot immunoassay (DTBIA) were developed for sensitive, simple, and rapid detection of TYLCV in field tomato and whitefly (Bemisia tabaci) samples collected from TYLCV prevalent provinces in China. Using the hybridoma technology, six murine MAbs (1C4, 8D10, 6E3, 2F2, 3F4 and 4G3) against TYLCV were prepared. Using the MAb 1C4, dot-ELISA and DTBIA were then established for detecting TYLCV in field tomato and whitefly samples collected from TYLCV prevalent provinces in China. The dot-ELISA could detect TYLCV in infected tissue crude extract diluted at 1:5,120 (w/v, g mL-1), and in viruliferous whitefly homogenate diluted at 1:128 (individual whitefly/μL), respectively. Field tomato samples (n=487) and whitefly samples (n=110) from TYLCV prevalent districts in China were screened for the presence of TYLCV using the two developed methods, and the results were further confirmed by PCR and nucleotide sequencing. The survey revealed that TYLCV is widespread on tomato plants in Zhejiang, Shandong and Henan provinces in China. The developed dot-ELISA is very suitable for the routine detection of TYLCV in field tomato and whitefly samples, and the DTBIA is more suitable for the routine detection of TYLCV in large-scale tomato plant samples collected from TYLCV prevalent areas.

Long-Term Outcomes of an Antimicrobial Stewardship Program Implemented in a Hospital with Low Baseline Antibiotic Use

PubMed Central

Jenkins, Timothy C.; Knepper, Bryan C.; Shihadeh, Katherine; Haas, Michelle K.; Sabel, Allison L.; Steele, Andrew W.; Wilson, Michael L.; Price, Connie S.; Burman, William J.; Mehler, Philip S.

2016-01-01

Objective To evaluate the long-term outcomes of an antimicrobial stewardship program (ASP) implemented in a hospital with low baseline antibiotic use Design Quasi-experimental, interrupted-time series study Setting 525-bed public safety-net hospital Intervention Implementation of a formal ASP in July 2008 Methods We conducted a time-series analysis to evaluate the impact of the ASP over a 6.25-year period (July 1, 2008 – September 30, 2014) while controlling for trends during a 3-year preintervention period (July 1, 2005 – June 30, 2008). The primary outcome measures were total antibacterial and antipseudomonal use in days of therapy (DOT) per 1000 patient-days (PD). Secondary outcomes included antimicrobial costs and resistance, hospital-onset C. difficile infection, and other patient-centered measures. Results During the preintervention period, total antibacterial and antipseudomonal use were declining (−9.2 and −5.5 DOT/1000 PD per quarter, respectively). During the stewardship period, both continued to decline, although at lower rates (−3.7 and −2.2 DOT/1000 PD, respectively), resulting in a slope change of 5.5 DOT/1000 PD per quarter for total antibacterial use (P = .10) and 3.3 DOT/100 PD per quarter for antipseudomonal use (P = .01). Antibiotic expenditures declined markedly during the stewardship period (−$295.42/1000PD per quarter, p=.002). There were variable changes in antimicrobial resistance and few apparent changes in C. difficile infection and other patient-centered outcomes. Conclusion In a hospital with low baseline antibiotic use, implementation of an ASP was associated with sustained reductions in total antibacterial and antipseudomonal use and declining antibiotic expenditures; however, this study highlights limitations of commonly used stewardship outcome measures. PMID:25740560

Development of a Quantum Dot, 0.6 eV InGaAs Thermophotovoltaic (TPV) Converter

NASA Technical Reports Server (NTRS)

Forbes, David; Sinharoy, Samar; Raffalle, Ryne; Weizer, Victor; Homann, Natalie; Valko, Thomas; Bartos,Nichole; Scheiman, David; Bailey, Sheila

2007-01-01

Thermophotovoltaic (TPV) power conversion has to date demonstrated conversion efficiencies exceeding 20% when coupled to a heat source. Current III-V semiconductor TPV technology makes use of planar devices with bandgaps tailored to the heat source. The efficiency can be improved further by increasing the collection efficiency through the incorporation of InAs quantum dots. The use of these dots can provide sub-gap absorption and thus improve the cell short circuit current without the normal increase in dark current associated with lowering the bandgap. We have developed self-assembled InAs quantum dots using the Stranski-Krastanov growth mode on 0.74 eV In0.53GaAs lattice-matched to InP and also on lattice-mismatched 0.6 eV In0.69GaAs grown on InP through the use of a compositionally graded InPAsx buffer structure, by metalorganic vapor phase epitaxy (MOVPE). Atomic force microscopy (AFM) measurements showed that the most reproducible dot pattern was obtained with 5 monolayers of InAs grown at 450 C. The lattice mismatch between InAs and In0.69GaAs is only 2.1%, compared to 3.2% between InAs and In0.53GaAs. The smaller mismatch results in lower strain, making dot formation somewhat more complicated, resulting in quantum dashes, rather than well defined quantum dots in the lattice-mismatched case. We have fabricated 0.6 eV InGaAs planer TPV cells with and without the quantum dashes

Relationship Between Skating Economy and Performance During a Repeated-Shift Test in Elite and Subelite Ice Hockey Players.

PubMed

Lamoureux, Nicholas R; Tomkinson, Grant R; Peterson, Benjamin J; Fitzgerald, John S

2018-04-01

Lamoureux, NR, Tomkinson, GR, Peterson, BJ, and Fitzgerald, JS. Relationship between skating economy and performance during a repeated-shift test in elite and subelite ice hockey players. J Strength Cond Res 32(4): 1109-1113, 2018-The purpose of this study was to determine the importance of skating economy to fatigue during repeated high-intensity efforts of a simulated ice hockey shift. Forty-five collegiate and Junior A male ice hockey players (aged 18-24 years) performed a continuous graded exercise test using a skate treadmill. Breath-by-breath data for oxygen consumption (V[Combining Dot Above]O2) and respiratory exchange ratio were collected and used to derive energy expenditure (EE) averaged over the final 10 seconds of each stage. Economy was determined as the slope of the regression line relating V[Combining Dot Above]O2 and EE against skating speed separately. Participants also completed 8 bouts of maximal ice skating through a course designed to simulate typical shift, with timing gates determining first half, second half, and total fatigue decrement, calculated by a percent decrement score. Partial correlation was used to determine the association between economy measures and decrement during the repeated-shift test. Twenty-six participants met inclusion criteria and were included in data analysis. Skating economy measures (both relative V[Combining Dot Above]O2 and EE) were very likely moderate positive correlates of total fatigue decrement (r [95% confidence interval]: V[Combining Dot Above]O2, 0.46 [0.09, 0.72] and EE, 0.44, [0.06, 0.71]) but not with first or second gate decrement. Our results indicate that skating economy plays an important role in fatigue resistance over repeated on-ice sprints designed to simulate a typical shift. This supports the use of technical skating coaching and training techniques to enhance skating economy as a means of improving ice hockey performance.

Effects of Energy Drinks on Economy and Cardiovascular Measures.

PubMed

Peveler, Willard W; Sanders, Gabe J; Marczinski, Cecile A; Holmer, Brady

2017-04-01

Peveler, WW, Sanders, GJ, Marczinski, CA, and Holmer, B. Effects of energy drinks on economy and cardiovascular measures. J Strength Cond Res 31(4): 882-887, 2017-The use of energy drinks among athletes has risen greatly. Caffeine and taurine are the 2 primary performance enhancing ingredients found in energy drinks. The number of emergency department visits involving energy drinks doubled over the past 5 years. Reviews of the health complications have highlighted adverse cardiovascular events. The literature reveals that caffeine is known to moderately increase blood pressure (BP) and heart rate (HR). The purpose of this study was to determine the effect of 3 different energy drinks on cardiovascular and performance measures. Fifteen recreational runners completed 5 trials. The first trial consisted of a graded exercise protocol. The 4 remaining trials consisted of 15-minute economy trials at a treadmill speed consistent with 70% of subject's V[Combining Dot Above]O2max. An hour before subjects ingested 1 of the 3 energy drinks or a placebo. HR, BP, V[Combining Dot Above]O2, and rating of perceived exertion (RPE) were recorded during the 15-minute trial. Mean values for dependent measures were compared using repeated-measures analysis of variance. Fifteen-minute systolic BP readings were significantly lower in the placebo trials (156.93 ± 15.50) in relation to the 3 energy drink trials (163.87 ± 13.30, 166.47 ± 13.71, and 165.00 ± 15.23). There were no significant differences in diastolic BP and HR. There were no significant differences found in V[Combining Dot Above]O2 or RPE measures. Ingestion of energy drinks demonstrated no change in V[Combining Dot Above]O2 or RPE during the economy trials. The findings show no performance benefits under the conditions of this study. However, there does appear to be a significant increase in systolic BP.

Determinants of tuberculosis transmission and treatment abandonment in Fortaleza, Brazil.

PubMed

Harling, Guy; Lima Neto, Antonio S; Sousa, Geziel S; Machado, Marcia M T; Castro, Marcia C

2017-05-25

Tuberculosis (TB) remains a public health problem, despite recent achievements in reducing incidence and mortality rates. In Brazil, these achievements were above the worldwide average, but marked by large regional heterogeneities. In Fortaleza (5th largest city in Brazil), the tuberculosis cure rate has been declining and treatment abandonment has been increasing in the past decade, despite a reduction in incidence and an increase in directly observed therapy (DOT). These trends put efforts to eliminate tuberculosis at risk. We therefore sought to determine social and programmatic determinants of tuberculosis incidence and treatment abandonment in Fortaleza. We analyzed sociodemographic and clinical data for all new tuberculosis cases notified in the Notifiable Diseases Information System (SINAN) from Fortaleza between 2007 and 2014. We calculated incidence rates for 117 neighborhoods in Fortaleza, assessed their spatial clustering, and used spatial regression models to quantify associations between neighborhood-level covariates and incidence rates. We used hierarchical logistic regression models to evaluate how individual- and neighborhood-level covariates predicted tuberculosis treatment abandonment. There were 12,338 new cases reported during the study period. Case rates across neighborhoods were significantly positively clustered in two low-income areas close to the city center. In an adjusted model, tuberculosis rates were significantly higher in neighborhoods with lower literacy, higher sewerage access and homicide rates, and a greater proportion of self-reported black residents. Treatment was abandoned in 1901 cases (15.4%), a rate that rose by 71% between 2007 and 2014. Abandonment was significantly associated with many individual sociodemographic and clinical factors. Notably, being recommended for DOT was protective for those who completed DOT, but associated with abandonment for those who did not. Low socioeconomic status areas have higher tuberculosis rates, and low socioeconomic individuals have higher risk of treatment abandonment, in Fortaleza. Treatment abandonment rates are growing despite the advent of universal DOT recommendations in Brazil. Proactive social policies, and active contact tracing to find missed cases, may help reduce the tuberculosis burden in this setting.

Covalent Linking Greatly Enhances Photoinduced Electron Transfer in Fullerene-Quantum Dot Nanocomposites: Time-Domain Ab Initio Study.

PubMed

Chaban, Vitaly V; Prezhdo, Victor V; Prezhdo, Oleg V

2013-01-03

Nonadiabatic molecular dynamics combined with time-domain density functional theory are used to study electron transfer (ET) from a CdSe quantum dot (QD) to the C60 fullerene, occurring in several types of hybrid organic/inorganic nanocomposites. By unveiling the time dependence of the ET process, we show that covalent bonding between the QD and C60 is particularly important to ensure ultrafast transmission of the excited electron from the QD photon-harvester to the C60 electron acceptor. Despite the close proximity of the donor and acceptor species provided by direct van der Waals contact, it leads to a notably weaker QD-C60 interaction than a lengthy molecular bridge. We show that the ET rate in a nonbonded mixture of QDs and C60 can be enhanced by doping. The photoinduced ET is promoted primarily by mid- and low-frequency vibrations. The study establishes the basic design principles for enhancing photoinduced charge separation in nanoscale light harvesting materials.

The new high-pressure borate Co{sub 7}B{sub 24}O{sub 42}(OH){sub 2}{center_dot}2 H{sub 2}O-Formation of edge-sharing BO{sub 4} tetrahedra in a hydrated borate

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

Neumair, Stephanie C.; Kaindl, Reinhard; Huppertz, Hubert, E-mail: hubert.huppertz@uibk.ac.at

2012-01-15

The new borate hydrate Co{sub 7}B{sub 24}O{sub 42}(OH){sub 2}{center_dot}2 H{sub 2}O was synthesized under high-pressure/high-temperature conditions of 6 GPa and 880 Degree-Sign C in a Walker-type multianvil apparatus. The compound crystallizes in the orthorhombic space group Pbam (Z=2) with the lattice parameters a=819.0(2), b=2016.9(4), c=769.9(2) pm, V=1.2717(4) nm{sup 3}, R{sub 1}=0.0758, wR{sub 2}=0.0836 (all data). The new structure type of Co{sub 7}B{sub 24}O{sub 42}(OH){sub 2}{center_dot}2 H{sub 2}O is built up from corner-sharing BO{sub 4} tetrahedra forming corrugated layers, that are interconnected among each other by two edge-sharing BO{sub 4} tetrahedra (B{sub 2}O{sub 6} units) forming Z-shaped channels. Interestingly, the heremore » presented structure of Co{sub 7}B{sub 24}O{sub 42}(OH){sub 2}{center_dot}2 H{sub 2}O is closely related to the structures of M{sub 6}B{sub 22}O{sub 39}{center_dot}H{sub 2}O (M=Fe, Co), which exhibit BO{sub 4} tetrahedra in an intermediate state on the way to edge-sharing BO{sub 4} tetrahedra. - Graphical Abstract: The new high-pressure borate hydrate Co{sub 7}B{sub 24}O{sub 42}(OH){sub 2}{center_dot}2 H{sub 2}O is built up from corner-sharing BO{sub 4} tetrahedra forming corrugated layers, that are interconnected among each other by two edge-sharing BO{sub 4} tetrahedra (B{sub 2}O{sub 6} units). In this paper we report on synthesis, structural details, and properties of the new compound Co{sub 7}B{sub 24}O{sub 42}(OH){sub 2}{center_dot}2 H{sub 2}O. Highlights: Black-Right-Pointing-Pointer High-pressure/high-temperature synthesis of the new borate hydrate Co{sub 7}B{sub 24}O{sub 42}(OH){sub 2}{center_dot}2 H{sub 2}O. Black-Right-Pointing-Pointer In the structure of Co{sub 7}B{sub 24}O{sub 42}(OH){sub 2}{center_dot}2 H{sub 2}O, two B{sub 2}O{sub 6} units are connected to 'vierer' rings. Black-Right-Pointing-Pointer Pressure favours the formation of edge-sharing BO{sub 4} tetrahedra in the chemistry of borates.« less

Geometrical behavior of hydrogen bonding patterns in the alpha-dodecyl-omega-hydroxy-tris(oxyethylene)-water system monitored by near infrared spectroscopy.

PubMed

Ohno, Keiichi; Takao, Hiroshi; Katsumoto, Yukiteru

2006-03-01

Changes in the geometry of hydrogen bonding patterns in the alpha-dodecyl-omega-hydroxy-tris(oxyethylene) (C(12)E(3))-water system have been investigated by near infrared (NIR) spectroscopy. In the 5,300-4,600 cm(-1) region, the characteristic bands for C(12)E(3) and water can be separately investigated, since the combination bands of the OH stretching and its COH bending of alcohols are observed at 5,000-4,650 cm(-1), whereas the combination bands of the OH stretching and its HOH bending of water, at 5,300-5,000 cm(-1). The NIR result has revealed that the addition of water to C(12)E(3) promotes the formation of the OHcdots, three dots, centeredOHcdots, three dots, centeredO hydrogen bonds.

Excitation power dependence of photoluminescence spectra of GaSb type-II quantum dots in GaAs grown by droplet epitaxy

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

Kawazu, T., E-mail: KAWAZU.Takuya@nims.go.jp; Noda, T.; Sakuma, Y.

2016-04-15

We investigated the excitation power P dependence of photoluminescence (PL) spectra of GaSb type-II quantum dots (QDs) in GaAs grown by droplet epitaxy. We prepared two QD samples annealed at slightly different temperatures (380 {sup o}C and 400 {sup o}C) and carried out PL measurements. The 20 {sup o}C increase of the annealing temperature leads to (1) about 140 and 60 times stronger wetting layer (WL) luminescence at low and high P, (2) about 45% large energy shift of QD luminescence with P, and (3) the different P dependence of the PL intensity ratio between the QD and the WL. These differences ofmore » the PL characteristics are explained by the effects of the WL.« less

Prediction of the optimum hybridization conditions of dot-blot-SNP analysis using estimated melting temperature of oligonucleotide probes.

PubMed

Shiokai, Sachiko; Kitashiba, Hiroyasu; Nishio, Takeshi

2010-08-01

Although the dot-blot-SNP technique is a simple cost-saving technique suitable for genotyping of many plant individuals, optimization of hybridization and washing conditions for each SNP marker requires much time and labor. For prediction of the optimum hybridization conditions for each probe, we compared T (m) values estimated from nucleotide sequences using the DINAMelt web server, measured T (m) values, and hybridization conditions yielding allele-specific signals. The estimated T (m) values were comparable to the measured T (m) values with small differences of less than 3 degrees C for most of the probes. There were differences of approximately 14 degrees C between the specific signal detection conditions and estimated T (m) values. Change of one level of SSC concentrations of 0.1, 0.2, 0.5, and 1.0x SSC corresponded to a difference of approximately 5 degrees C in optimum signal detection temperature. Increasing the sensitivity of signal detection by shortening the exposure time to X-ray film changed the optimum hybridization condition for specific signal detection. Addition of competitive oligonucleotides to the hybridization mixture increased the suitable hybridization conditions by 1.8. Based on these results, optimum hybridization conditions for newly produced dot-blot-SNP markers will become predictable.

Circuit quantum electrodynamics with a spin qubit.

PubMed

Petersson, K D; McFaul, L W; Schroer, M D; Jung, M; Taylor, J M; Houck, A A; Petta, J R

2012-10-18

Electron spins trapped in quantum dots have been proposed as basic building blocks of a future quantum processor. Although fast, 180-picosecond, two-quantum-bit (two-qubit) operations can be realized using nearest-neighbour exchange coupling, a scalable, spin-based quantum computing architecture will almost certainly require long-range qubit interactions. Circuit quantum electrodynamics (cQED) allows spatially separated superconducting qubits to interact via a superconducting microwave cavity that acts as a 'quantum bus', making possible two-qubit entanglement and the implementation of simple quantum algorithms. Here we combine the cQED architecture with spin qubits by coupling an indium arsenide nanowire double quantum dot to a superconducting cavity. The architecture allows us to achieve a charge-cavity coupling rate of about 30 megahertz, consistent with coupling rates obtained in gallium arsenide quantum dots. Furthermore, the strong spin-orbit interaction of indium arsenide allows us to drive spin rotations electrically with a local gate electrode, and the charge-cavity interaction provides a measurement of the resulting spin dynamics. Our results demonstrate how the cQED architecture can be used as a sensitive probe of single-spin physics and that a spin-cavity coupling rate of about one megahertz is feasible, presenting the possibility of long-range spin coupling via superconducting microwave cavities.

Space Exploration

NASA Technical Reports Server (NTRS)

Gallagher, Dennis

2017-01-01

New range Passage Tomb may be the first structure with known astronomical significance. It was built around 3,200 B.C. in Ireland. It's central passage allows light end-to-end for about 2 weeks around winter solstice. The Sun, Moon, Planets, and Stars held significance in early times due to the seasons, significance for food crops, and mythology. Citation: Corel Photography and Windows to the Universe The Greek may be among the first to pursue analytical interpretations of what they saw in the sky. In about 280 B.C. Aristarchus suggested Earth revolves around the Sun and estimated the distance between. Around 130 B.C. Hipparchus developed the first accurate star map. Today still seek to understand how the universe formed and how we came to be and are we alone. Understanding the causes and consequences of climate change using advanced space missions with major Earth science and applications research. center dotFire the public imagination and inspire students to pursue STEM fields. Train college and graduate students to create a U.S. technical workforce with employees that embody the values of competence, innovation, and service. center dotDrive the technical innovations that enable exploration and become the engine of National economic growth. center dotPartner domestically and internationally to leverage resources to extend the reach of research.

An advanced dual labeled gold nanoparticles probe to detect Cryptosporidium parvum using rapid immuno-dot blot assay.

PubMed

Thiruppathiraja, Chinnasamy; Kamatchiammal, Senthilkumar; Adaikkappan, Periyakaruppan; Alagar, Muthukaruppan

2011-07-15

The zoonotic protozoan parasite Cryptosporidium parvum poses a significant risk to public health. Due to the low infectious dose of C. parvum, remarkably sensitive detection methods are required for water and food industries analysis. However PCR affirmed sensing method of the causative nucleic acid has numerous advantages, still criterion demands for simple techniques and expertise understanding to extinguish its routine use. In contrast, protein based immuno detecting techniques are simpler to perform by a commoner, but lack of sensitivity due to inadequate signal amplification. In this paper, we focused on the development of a mere sensitive immuno detection method by coupling anti-cyst antibody and alkaline phosphatase on gold nanoparticle for C. parvum is described. Outcome of the sensitivity in an immuno-dot blot assay detection is enhanced by 500 fold (using conventional method) and visually be able to detect up to 10 oocysts/mL with minimal processing period. Techniques reported in this paper substantiate the convenience of immuno-dot blot assay for the routine screening of C. parvum in water/environmental examines and most importantly, demonstrates the potential of a prototype development of simple and inexpensive diagnostic technique. Copyright © 2011 Elsevier B.V. All rights reserved.

The Erdős-Rothschild problem on edge-colourings with forbidden monochromatic cliques

NASA Astrophysics Data System (ADS)

Pikhurko, Oleg; Staden, Katherine; Yilma, Zelealem B.

2017-09-01

Let $\\mathbf{k} := (k_1,\\dots,k_s)$ be a sequence of natural numbers. For a graph $G$, let $F(G;\\mathbf{k})$ denote the number of colourings of the edges of $G$ with colours $1,\\dots,s$ such that, for every $c \\in \\{1,\\dots,s\\}$, the edges of colour $c$ contain no clique of order $k_c$. Write $F(n;\\mathbf{k})$ to denote the maximum of $F(G;\\mathbf{k})$ over all graphs $G$ on $n$ vertices. This problem was first considered by Erd\\H{o}s and Rothschild in 1974, but it has been solved only for a very small number of non-trivial cases. We prove that, for every $\\mathbf{k}$ and $n$, there is a complete multipartite graph $G$ on $n$ vertices with $F(G;\\mathbf{k}) = F(n;\\mathbf{k})$. Also, for every $\\mathbf{k}$ we construct a finite optimisation problem whose maximum is equal to the limit of $\\log_2 F(n;\\mathbf{k})/{n\\choose 2}$ as $n$ tends to infinity. Our final result is a stability theorem for complete multipartite graphs $G$, describing the asymptotic structure of such $G$ with $F(G;\\mathbf{k}) = F(n;\\mathbf{k}) \\cdot 2^{o(n^2)}$ in terms of solutions to the optimisation problem.

Nitrogen and sulfur co-doped carbon dots with strong blue luminescence.

PubMed

Ding, Hui; Wei, Ji-Shi; Xiong, Huan-Ming

2014-11-21

Sulfur-doped carbon dots (S-CDs) with a quantum yield (QY) of 5.5% and nitrogen, sulfur co-doped carbon dots (N,S-CDs) with a QY of 54.4% were synthesized, respectively, via the same hydrothermal route using α-lipoic acid as the carbon source. The obtained S-CDs and N,S-CDs had similar sizes but different optical features. The QY of N,S-CDs was gradually enhanced when extending the reaction time to increase the nitrogen content. After careful characterization of these CDs, the doped nitrogen element was believed to be in the form of C=N and C-N bonds which enhanced the fluorescence efficiency significantly. Meanwhile, the co-doped sulfur element was found to be synergistic for nitrogen doping in N,S-CDs. The optimal N,S-CDs were successfully employed as good multicolor cell imaging probes due to their fine dispersion in water, excitation-dependent emission, excellent fluorescence stability and low toxicity. Besides, such N,S-CDs showed a wide detection range and excellent accuracy as fluorescent sensors for Fe(3+) ions.

Novel Synthesis of Slightly Fluorinated Graphene Quantum Dots with Luminescent and Paramagnetic Properties through Thermal Cutting of Fluorinated Graphene

PubMed Central

Feng, Qian; Xiao, Wenqing; Zheng, Yongping; Lin, Yuda; Li, Jiaxin; Ye, Qingying; Huang, Zhigao

2018-01-01

A novel approach has been developed to synthesize slightly fluorinated graphene quantum dots (GQDs-F) through thermal cutting of highly fluorinated graphene. The fluorinated graphene with substantial structure defects is fragile and is readily attacked. The direct evaporation of abundant CFn (n = 2, 3) groups near structure defects lead to the loss of adjacent skelton C atoms, and the fluorinated graphene can be thermally cut into GQDs-F with a relatively uniform nanosize in pyrolysis at 810 K. The GQDs-F with a low F/C atomic ratio of ca. 0.03 exhibit excitation wavelength-dependent properties with multicolor photoluminescence (PL) from blue to green. At the same time, F adatoms that are most likely located at the edges of GQDs-F have a high efficiency of introducing paramagnetic centres, and GQDs-F show a strong paramagnetism because of sp3-type defects and magnetic zigzag edges. The graphene quantum dots with such multimodal capabilities should have great applied value in material science. PMID:29316730

77 FR 35617 - Amendment of Class C Airspace; Colorado Springs, CO

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-14

... 44 U.S.C. 1510. #0; #0;The Code of Federal Regulations is sold by the Superintendent of Documents. #0...; Airspace Docket No. 12-AWA-4] Amendment of Class C Airspace; Colorado Springs, CO AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: This action modifies the Colorado Springs, CO, Class C...

77 FR 50954 - Airworthiness Directives; Cessna Aircraft Company

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-23

... Company (Cessna) Model 402C airplanes modified by Sierra Industries, Ltd. Supplemental Type Certificate... Airworthiness Directives; Cessna Aircraft Company AGENCY: Federal Aviation Administration (FAA), DOT. ACTION... earlier proposed airworthiness directive (AD) for all Cessna Aircraft Company (Cessna) Model 402C...

Spatial and temporal compact equations for water waves

NASA Astrophysics Data System (ADS)

Dyachenko, Alexander; Kachulin, Dmitriy; Zakharov, Vladimir

2016-04-01

A one-dimensional potential flow of an ideal incompressible fluid with a free surface in a gravity field is the Hamiltonian system with the Hamiltonian: H = 1/2intdxint-∞^η |nablaφ|^2dz + g/2ont η^2dxŗφ(x,z,t) - is the potential of the fluid, g - gravity acceleration, η(x,t) - surface profile Hamiltonian can be expanded as infinite series of steepness: {Ham4} H &=& H2 + H3 + H4 + dotsŗH2 &=& 1/2int (gη2 + ψ hat kψ) dx, ŗH3 &=& -1/2int \\{(hat kψ)2 -(ψ_x)^2}η dx,ŗH4 &=&1/2int {ψxx η2 hat kψ + ψ hat k(η hat k(η hat kψ))} dx. where hat k corresponds to the multiplication by |k| in Fourier space, ψ(x,t)= φ(x,η(x,t),t). This truncated Hamiltonian is enough for gravity waves of moderate amplitudes and can not be reduced. We have derived self-consistent compact equations, both spatial and temporal, for unidirectional water waves. Equations are written for normal complex variable c(x,t), not for ψ(x,t) and η(x,t). Hamiltonian for temporal compact equation can be written in x-space as following: {SPACE_C} H = intc^*hat V c dx + 1/2int [ i/4(c2 partial/partial x {c^*}2 - {c^*}2 partial/partial x c2)- |c|2 hat K(|c|^2) ]dx Here operator hat V in K-space is so that Vk = ω_k/k. If along with this to introduce Gardner-Zakharov-Faddeev bracket (for the analytic in the upper half-plane function) {GZF} partial^+x Leftrightarrow ikθk Hamiltonian for spatial compact equation is the following: {H24} &&H=1/gint1/ω|cω|2 dω +ŗ&+&1/2g^3int|c|^2(ddot c^*c + ddot c c^*)dt + i/g^2int |c|^2hatω(dot c c* - cdot c^*)dt. equation of motion is: {t-space} &&partial /partial xc +i/g partial^2/partial t^2c =ŗ&=& 1/2g^3partial^3/partial t3 [ partial^2/partial t^2(|c|^2c) +2 |c|^2ddot c +ddot c^*c2 ]+ŗ&+&i/g3 partial^3/partial t3 [ partial /partial t( chatω |c|^2) + dot c hatω |c|2 + c hatω(dot c c* - cdot c^*) ]. It solves the spatial Cauchy problem for surface gravity wave on the deep water. Main features of the equations are: Equations are written for complex normal variable c(x,t) which is analytic function in the upper half-planeHamiltonians both for temporal and spatial equations are very simple It can be easily implemented for numerical simulation The equations can be generalized for "almost" 2-D waves like KdV is generalized to KP. This work was supported by was Grant "Wave turbulence: theory, numerical simulation, experiment" #14-22-00174 of Russian Science Foundation.

Control of Emission Color of High Quantum Yield CH3NH3PbBr3 Perovskite Quantum Dots by Precipitation Temperature.

PubMed

Huang, He; Susha, Andrei S; Kershaw, Stephen V; Hung, Tak Fu; Rogach, Andrey L

2015-09-01

Emission color controlled, high quantum yield CH 3 NH 3 PbBr 3 perovskite quantum dots are obtained by changing the temperature of a bad solvent during synthesis. The products for temperatures between 0 and 60 °C have good spectral purity with narrow emission line widths of 28-36 nm, high absolute emission quantum yields of 74% to 93%, and short radiative lifetimes of 13-27 ns.

The Current Status of the Disease Caused by Enterovirus 71 Infections: Epidemiology, Pathogenesis, Molecular Epidemiology, and Vaccine Development.

PubMed

Chang, Ping-Chin; Chen, Shou-Chien; Chen, Kow-Tong

2016-09-09

Enterovirus 71 (EV71) infections have a major public health impact in the Asia-Pacific region. We reviewed the epidemiology, pathogenesis, and molecular epidemiology of EV71 infection as well as EV71 vaccine development. Previous studies were found using the search terms "enterovirus 71" and "epidemiology" or "pathogenesis" or "molecular epidemiology" or "vaccine" in Medline and PubMed. Articles that were not published in the English language, manuscripts without an abstract, and opinion articles were excluded from the review. The reported epidemiology of cases caused by EV71 infection varied from country to country; seasonal variations in incidence were observed. Most cases of EV71 infection that resulted in hospitalization for complications occurred in children less than five years old. The brainstem was the most likely major target of EV71 infection. The emergence of the EV71 epidemic in the Asia-Pacific region has been associated with the circulation of different genetic lineages (genotypes B3, B4, C1, C2, and C4) that appear to be undergoing rapid evolutionary changes. The relationship between the gene structure of the EV71 virus and the factors that ensure its survival, circulation, and evasion of immunity is still unknown. EV71 infection has emerged as an important global public health problem. Vaccine development, including the development of inactivated whole-virus live attenuated, subviral particles, and DNA vaccines, has been progressing.

The Current Status of the Disease Caused by Enterovirus 71 Infections: Epidemiology, Pathogenesis, Molecular Epidemiology, and Vaccine Development

PubMed Central

Chang, Ping-Chin; Chen, Shou-Chien; Chen, Kow-Tong

2016-01-01

Enterovirus 71 (EV71) infections have a major public health impact in the Asia-Pacific region. We reviewed the epidemiology, pathogenesis, and molecular epidemiology of EV71 infection as well as EV71 vaccine development. Previous studies were found using the search terms “enterovirus 71” and “epidemiology” or “pathogenesis” or “molecular epidemiology” or “vaccine” in Medline and PubMed. Articles that were not published in the English language, manuscripts without an abstract, and opinion articles were excluded from the review. The reported epidemiology of cases caused by EV71 infection varied from country to country; seasonal variations in incidence were observed. Most cases of EV71 infection that resulted in hospitalization for complications occurred in children less than five years old. The brainstem was the most likely major target of EV71 infection. The emergence of the EV71 epidemic in the Asia-Pacific region has been associated with the circulation of different genetic lineages (genotypes B3, B4, C1, C2, and C4) that appear to be undergoing rapid evolutionary changes. The relationship between the gene structure of the EV71 virus and the factors that ensure its survival, circulation, and evasion of immunity is still unknown. EV71 infection has emerged as an important global public health problem. Vaccine development, including the development of inactivated whole-virus live attenuated, subviral particles, and DNA vaccines, has been progressing. PMID:27618078

Online attention modification for social anxiety disorder: replication of a randomized controlled trial.

PubMed

Carleton, R Nicholas; Teale Sapach, Michelle J N; Oriet, Chris; LeBouthillier, Daniel M

2017-01-01

Social anxiety disorder (SAD) models posit vigilance for external social threat cues and exacerbated self-focused attention as key in disorder development and maintenance. Evidence indicates a modified dot-probe protocol may reduce symptoms of SAD; however, the efficacy when compared to a standard protocol and long-term maintenance of treatment gains remains unclear. Furthermore, the efficacy of such protocols on SAD-related constructs remains relatively unknown. The current investigation clarified these associations using a randomized control trial replicating and extending previous research. Participants with SAD (n = 113; 71% women) were randomized to complete a standard (i.e. control) or modified (i.e. active) dot-probe protocol consisting of 15-min sessions twice weekly for four weeks. Self-reported symptoms were measured at baseline, post-treatment, and 4-month and 8-month follow-ups. Hierarchical linear modeling indicated significant self-reported reductions in symptoms of social anxiety, fear of negative evaluation, trait anxiety, and depression, but no such reductions in fear of positive evaluation. Symptom changes did not differ based on condition and were maintained at 8-month follow-up. Attentional biases during the dot-probe task were not related to symptom change. Overall, our results replicate support for the efficacy of both protocols in reducing symptoms of SAD and specific related constructs, and suggest a role of exposure, expectancy, or practice effects, rather than attention modification, in effecting such reductions. The current results also support distinct relationships between fears of negative and positive evaluation and social anxiety. Further research focused on identifying the mechanisms of change in attention modification protocols appears warranted.

Tuberculosis Costs in Spain and Related Factors.

PubMed

Gullón, José Antonio; García-García, José María; Villanueva, Manuel Ángel; Álvarez-Navascues, Fernando; Rodrigo, Teresa; Casals, Martí; Anibarro, Luis; García-Clemente, Marta María; Jiménez, María Ángeles; Bustamante, Ana; Penas, Antón; Caminero, José Antonio; Caylà, Joan

2016-12-01

To analyze the direct and indirect costs of diagnosis and management of tuberculosis (TB) and associated factors. Prospective study of patients diagnosed with TB between September 2014 and September 2015. We calculated direct (hospital stays, visits, diagnostic tests, and treatment) and indirect (sick leave and loss of productivity, contact tracing, and rehabilitation) costs. The following cost-related variables were compared: age, gender, country of origin, hospital stays, diagnostic testing, sensitivity testing, treatment, resistance, directed observed therapy (DOT), and days of sick leave. Proportions were compared using the chi-squared test and significant variables were included in a logistic regression analysis to calculate odds ratio (OR) and corresponding 95% confidence intervals. 319 patients were included with a mean age of 56.72±20.79 years. The average cost was €10,262.62±14,961.66, which increased significantly when associated with hospital admission, polymerase chain reaction, sputum smears and cultures, sensitvity testing, chest computed tomography, pleural biopsy, drug treatment longer than nine months, DOT and sick leave. In the multivariate analysis, hospitalization (OR=96.8; CI 29-472), sensitivity testing (OR=4.34; CI 1.71-12.1), chest CT (OR= 2.25; CI 1.08-4.77), DOT (OR=20.76; CI 4.11-148) and sick leave (OR=26,9; CI 8,51-122) showed an independent association with cost. Tuberculosis gives rise to significant health spending. In order to reduce these costs, more control of transmission, and fewer hospital admissions would be required. Copyright © 2016 SEPAR. Publicado por Elsevier España, S.L.U. All rights reserved.

Economic evaluation of public-private mix for tuberculosis care and control, India. Part II. Cost and cost-effectiveness.

PubMed

Pantoja, A; Lönnroth, K; Lal, S S; Chauhan, L S; Uplekar, M; Padma, M R; Unnikrishnan, K P; Rajesh, J; Kumar, P; Sahu, S; Wares, F; Floyd, K

2009-06-01

Bangalore City, India. To assess the cost and cost-effectiveness of public-private mix (PPM) for tuberculosis (TB) care and control when implemented on a large scale. DOTS implementation under the Revised National TB Control Programme (RNTCP) began in 1999, PPM was introduced in mid-2001 and a second phase of intensified PPM began in 2003. Data on the costs and effects of TB treatment from 1999 to 2005 were collected and used to compare the two distinct phases of PPM with a scenario of no PPM. Costs were assessed in 2005 $US for public and private providers, patients and patient attendants. Sources of data included expenditure records, medical records, interviews with staff and patient surveys. Effectiveness was measured as the number of cases successfully treated. When PPM was implemented, total provider costs increased in proportion to the number of successfully treated TB cases. The average cost per patient treated from the provider perspective when PPM was implemented was stable, at US$69, in the intensified phase compared with US$71 pre-PPM. PPM resulted in the shift of an estimated 7200 patients from non-DOTS to DOTS treatment over 5 years. PPM implementation substantially reduced costs to patients, such that the average societal cost per patient successfully treated fell from US$154 to US$132 in the 4 years following the initiation of PPM. Implementation of PPM on a large scale in an urban setting can be cost-effective, and considerably reduces the financial burden of TB for patients.

Prediction of Protection against Asian Enterovirus 71 Outbreak Strains by Cross-neutralizing Capacity of Serum from Dutch Donors, The Netherlands

PubMed Central

Koen, Gerrit; van Eijk, Hetty; Koekkoek, Sylvie M.; de Jong, Menno D.; Wolthers, Katja C.

2016-01-01

Outbreaks of human enterovirus 71 (EV-71) in Asia are related to high illness and death rates among children. To gain insight into the potential threat for the population of Europe, we determined the neutralizing activity in intravenous immunoglobulin (IVIg) batches and individual serum samples from donors in the Netherlands against EV-71 strains isolated in Europe and in Asia. All IVIg batches and 41%, 79%, and 65% of serum samples from children ≤5 years of age, women of childbearing age, and HIV-positive men, respectively, showed high neutralizing activity against a Dutch C1 strain, confirming widespread circulation of EV-71 in the Netherlands. Asian B3–4 and C4 strains were efficiently cross-neutralized, predicting possible protection against extensive circulation and associated outbreaks of those types in Europe. However, C2 and C5 strains that had few mutations in the capsid region consistently escaped neutralization, emphasizing the importance of monitoring antigenic diversity among circulating EV-71 strains. PMID:27533024

Synthesis and Structural Characterization of Magnesium Based Coordination Networks in Different Solvents

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

D Banerjee; J Finkelstein; A Smirnov

2011-12-31

Three magnesium based metal-organic frameworks, Mg{sub 3}(3,5-PDC){sub 3}(DMF){sub 3} {center_dot} DMF [1], Mg(3,5-PDC)(H{sub 2}O) {center_dot} (H{sub 2}O) [3], and Mg{sub 4}(3,5-PDC){sub 4}(DMF){sub 2}(H{sub 2}O){sub 2} {center_dot} 2DMF {center_dot} 4.5H{sub 2}O [4], and a 2-D coordination polymer, [Mg(3,5-PDC)(H{sub 2}O){sub 2}] [2] [PDC = pyridinedicarboxylate], were synthesized using a combination of DMF, methanol, ethanol, and water. Compound 1 [space group P2{sub 1}/n, a = 12.3475(5) {angstrom}, b = 11.1929(5) {angstrom}, c = 28.6734(12) {angstrom}, {beta} = 98.8160(10){sup o}, V = 3916.0(3) {angstrom}{sup 3}] consists of a combination of isolated and corner-sharing magnesium octahedra connected by the organic linkers to form a 3-Dmore » network with a 12.2 {angstrom} x 4.6 {angstrom} 1-D channel. The channel contains coordinated and free DMF molecules. In compound 2 [space group C2/c, a = 9.964(5) {angstrom}, b = 12.0694(6) {angstrom}, c = 7.2763(4) {angstrom}, {beta} = 106.4970(6){sup o}, V = 836.70(6) {angstrom}{sup 3}], PDC connects isolated seven coordinated magnesium polyhedra into a layered structure. Compound 3 [space group P6{sub 1}22, a = 11.479(1) {angstrom}, c = 14.735(3) {angstrom}, V = 1681.7(4) {angstrom}{sup 3}] (previously reported) contains isolated magnesium octahedra connected by the organic linker with each other forming a 3D network. Compound 4 [space group P2{sub 1}/c, a = 13.7442(14) {angstrom}, b = 14.2887(15) {angstrom}, c = 14.1178(14) {angstrom}, {beta} = 104.912(2){sup o}, V = 2679.2(5) {angstrom}{sup 3}] also exhibits a 3D network based on isolated magnesium octahedra with square cavities containing both disordered DMF and water molecules. The structural topologies originate due to the variable coordination ability of solvent molecules with the metal center. Water molecules coordinate with the magnesium metal centers preferably over other polar solvents (DMF, methanol, ethanol) used to synthesize the coordination networks. Despite testing multiple desolvation routes, we were unable to measure BET surface areas greater than 51.9 m{sup 2}/g for compound 1.« less

Synthesis and Structural Characterization of Magnesium Based Coordination Networks in Different Solvents

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

Banerjee, Debasis; Finkelstein, Jeffrey; Smirnov, A.

2015-10-15

Three magnesium based metal-organic frameworks, Mg{sub 3}(3,5-PDC){sub 3}(DMF){sub 3} {center_dot} DMF [1], Mg(3,5-PDC)(H{sub 2}O) {center_dot} (H{sub 2}O) [3], and Mg4(3,5-PDC)4(DMF){sub 2}(H{sub 2}O){sub 2} {center_dot} 2DMF {center_dot} 4.5H{sub 2}O [4], and a 2-D coordination polymer, [Mg(3,5-PDC)(H{sub 2}O){sub 2}] [2] [PDC = pyridinedicarboxylate], were synthesized using a combination of DMF, methanol, ethanol, and water. Compound 1 [space group P2{sub 1}/n, a = 12.3475(5) {angstrom}, b = 11.1929(5) {angstrom}, c = 28.6734(12) {angstrom}, {beta} = 98.8160(10){sup o}, V = 3916.0(3) {angstrom}{sup 3}] consists of a combination of isolated and corner-sharing magnesium octahedra connected by the organic linkers to form a 3-D network withmore » a 12.2 {angstrom} x 4.6 {angstrom} 1-D channel. The channel contains coordinated and free DMF molecules. In compound 2 [space group C2/c, a = 9.964(5) {angstrom}, b = 12.0694(6) {angstrom}, c = 7.2763(4) {angstrom}, {beta} = 106.4970(6){sup o}, V = 836.70(6) {angstrom}{sup 3}], PDC connects isolated seven coordinated magnesium polyhedra into a layered structure. Compound 3 [space group P6{sub 1}22, a = 11.479(1) {angstrom}, c = 14.735(3) {angstrom}, V = 1681.7(4) {angstrom}{sup 3}] (previously reported) contains isolated magnesium octahedra connected by the organic linker with each other forming a 3D network. Compound 4 [space group P2{sub 1}/c, a = 13.7442(14) {angstrom}, b = 14.2887(15) {angstrom}, c = 14.1178(14) {angstrom}, {beta} = 104.912(2){sup o}, V = 2679.2(5) {angstrom}{sup 3}] also exhibits a 3D network based on isolated magnesium octahedra with square cavities containing both disordered DMF and water molecules. The structural topologies originate due to the variable coordination ability of solvent molecules with the metal center. Water molecules coordinate with the magnesium metal centers preferably over other polar solvents (DMF, methanol, ethanol) used to synthesize the coordination networks. Despite testing multiple desolvation routes, we were unable to measure BET surface areas greater than 51.9 m{sup 2}/g for compound 1.« less

76 FR 63714 - Technical Standard Order (TSO)-C129a, Airborne Supplemental Navigation Equipment Using the Global...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-13

..., Airborne Supplemental Navigation Equipment Using the Global Positioning System (GPS) AGENCY: Federal Aviation Administration (FAA), DOT ACTION: Notice of cancellation of TSO-C129a, Airborne Supplemental... cancellation of TSO-C129a, Airborne Supplemental Navigation Equipment Using the Global Positioning System (GPS...

14C/C measurements support Andreev's internode method to determine lichen growth rates in Cladina stygia (Fr.) Ahti

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

Holt, E; Bench, G

2007-12-05

Growth rates and the ability to date an organism can greatly contribute to understanding its population biology and community dynamics. 1n 1954, Andreev proposed a method to date Cladina, a fruticose lichen, using total thallus length and number of internodes. No research, however, has demonstrated the reliability of this technique or compared its estimates to those derived by other means. In this study, we demonstrate the utility of {sup 14}C/C ratios to determine lichen age and growth rate in Cladina stygia (Fr.) Ahti collected from northwestern Alaska, USA. The average growth rate using {sup 14}C/C ratios was 6.5 mm {center_dot}more » yr{sup -1}, which was not significantly different from growth rates derived by Andreev's internode method (average = 6.2 mm {center_dot} yr{sup -1}); thus, suggesting the reliability of Andreev's simple field method for dating lichens. In addition, we found lichen growth rates appeared to differ with geographic location, yet did not seem related to ambient temperature and total precipitation.« less

Mono- and bis-tolylterpyridine iridium(III) complexes

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

Hinkle, Lindsay M.; Young, Jr., Victor G.; Mann, Kent R.

The first structure report of trichlorido[4'-(p-tolyl)-2,2':6',2{double_prime}-terpyridine]iridium(III) dimethyl sulfoxide solvate, [IrCl{sub 3}(C{sub 22}H{sub 17}N{sub 3})] {center_dot} C{sub 2}H{sub 6}OS, (I), is presented, along with a higher-symmetry setting of previously reported bis[4'-(p-tolyl)-2,2':6',2{double_prime}-terpyridine]iridium(III) tris(hexafluoridophosphate) acetonitrile disolvate, [Ir(C{sub 22}H{sub 17}N{sub 3})2](PF{sub 6}){sub 3} {center_dot} 2C{sub 2}H{sub 3}N, (II) [Yoshikawa, Yamabe, Kanehisa, Kai, Takashima & Tsukahara (2007). Eur. J. Inorg. Chem. pp. 1911-1919]. For (I), the data were collected with synchrotron radiation and the dimethyl sulfoxide solvent molecule is disordered over three positions, one of which is an inversion center. The previously reported structure of (II) is presented in the more appropriate C2/c space group.more » The iridium complex and one PF{sub 6}{sup -} anion lie on twofold axes in this structure, making half of the molecule unique.« less

Quality factor of luminescent solar concentrators and practical concentration limits attainable with semiconductor quantum dots

DOE PAGES

Klimov, Victor I.; Baker, Thomas A.; Lim, Jaehoon; ...

2016-05-09

In this study, luminescent solar concentrators (LSCs) can be utilized as both large-area collectors of solar radiation supplementing traditional photovoltaic cells as well as semitransparent “solar windows” that provide a desired degree of shading and simultaneously serve as power-generation units. An important characteristic of an LSC is a concentration factor (C) that can be thought of as a coefficient of effective enlargement (or contraction) of the area of a solar cell when it is coupled to the LSC. Here we use analytical and numerical Monte Carlo modeling in addition to experimental studies of quantum-dot-based LSCs to analyze the factors thatmore » influence optical concentration in practical devices. Our theoretical model indicates that the maximum value of C achievable with a given fluorophore is directly linked to the LSC quality factor (Q LSC) defined as the ratio of absorption coefficients at the wavelengths of incident and reemitted light. In fact, we demonstrate that the ultimate concentration limit (C 0) realized in large-area devices scales linearly with the LSC quality factor and in the case of perfect emitters and devices without back reflectors is approximately equal to Q LSC. To test the predictions of this model, we conduct experimental studies of LSCs based on visible-light emitting II–VI core/shell quantum dots with two distinct LSC quality factors. We also investigate devices based on near-infrared emitting CuInSe xS 2–x quantum dots for which the large emission bandwidth allows us to assess the impact of varied Q LSC on the concentration factor by simply varying the detection wavelength. In all cases, we find an excellent agreement between the model and the experimental observations, suggesting that the developed formalism can be utilized for express evaluation of prospective LSC performance based on the optical spectra of LSC fluorophores, which should facilitate future efforts on the development of high-performance devices based on quantum dots as well as other types of emitters.« less

Quality factor of luminescent solar concentrators and practical concentration limits attainable with semiconductor quantum dots

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

Klimov, Victor I.; Baker, Thomas A.; Lim, Jaehoon

In this study, luminescent solar concentrators (LSCs) can be utilized as both large-area collectors of solar radiation supplementing traditional photovoltaic cells as well as semitransparent “solar windows” that provide a desired degree of shading and simultaneously serve as power-generation units. An important characteristic of an LSC is a concentration factor (C) that can be thought of as a coefficient of effective enlargement (or contraction) of the area of a solar cell when it is coupled to the LSC. Here we use analytical and numerical Monte Carlo modeling in addition to experimental studies of quantum-dot-based LSCs to analyze the factors thatmore » influence optical concentration in practical devices. Our theoretical model indicates that the maximum value of C achievable with a given fluorophore is directly linked to the LSC quality factor (Q LSC) defined as the ratio of absorption coefficients at the wavelengths of incident and reemitted light. In fact, we demonstrate that the ultimate concentration limit (C 0) realized in large-area devices scales linearly with the LSC quality factor and in the case of perfect emitters and devices without back reflectors is approximately equal to Q LSC. To test the predictions of this model, we conduct experimental studies of LSCs based on visible-light emitting II–VI core/shell quantum dots with two distinct LSC quality factors. We also investigate devices based on near-infrared emitting CuInSe xS 2–x quantum dots for which the large emission bandwidth allows us to assess the impact of varied Q LSC on the concentration factor by simply varying the detection wavelength. In all cases, we find an excellent agreement between the model and the experimental observations, suggesting that the developed formalism can be utilized for express evaluation of prospective LSC performance based on the optical spectra of LSC fluorophores, which should facilitate future efforts on the development of high-performance devices based on quantum dots as well as other types of emitters.« less

Overcoming the errors of in-house PCR used in the clinical laboratory for the diagnosis of extrapulmonary tuberculosis.

PubMed

Kunakorn, M; Raksakai, K; Pracharktam, R; Sattaudom, C

1999-03-01

Our experiences from 1993 to 1997 in the development and use of IS6110 base PCR for the diagnosis of extrapulmonary tuberculosis in a routine clinical setting revealed that error-correcting processes can improve existing diagnostic methodology. The reamplification method initially used had a sensitivity of 90.91% and a specificity of 93.75%. The concern was focused on the false positive results of this method caused by product-carryover contamination. This method was changed to single round PCR with carryover prevention by uracil DNA glycosylase (UDG), resulting in a 100% specificity but only 63% sensitivity. Dot blot hybridization was added after the single round PCR, increasing the sensitivity to 87.50%. However, false positivity resulted from the nonspecific dot blot hybridization signal, reducing the specificity to 89.47%. The hybridization of PCR was changed to a Southern blot with a new oligonucleotide probe giving the sensitivity of 85.71% and raising the specificity to 99.52%. We conclude that the PCR protocol for routine clinical use should include UDG for carryover prevention and hybridization with specific probes to optimize diagnostic sensitivity and specificity in extrapulmonary tuberculosis testing.

Highly Efficient Carbon Dots with Reversibly Switchable Green-Red Emissions for Trichromatic White Light-Emitting Diodes.

PubMed

Yuan, Biao; Guan, Shanyue; Sun, Xingming; Li, Xiaoming; Zeng, Haibo; Xie, Zheng; Chen, Ping; Zhou, Shuyun

2018-05-09

Carbon dots (CDs) have potentials to be utilized in optoelectronic devices, bioimaging, and photocatalysis. The majority of the current CDs with high quantum yield to date were limited in the blue light emission region. Herein, on the basis of surface electron-state engineering, we report a kind of CDs with reversible switching ability between green and red photoluminescence with a quantum yield (QY) of both up to 80%. Highly efficient green and red solid-state luminescence is realized by doping CDs into a highly transparent matrix of methyltriethoxysilane and 3-triethoxysilylpropylamine to form CDs/gel glasses composites with QYs of 80 and 78%. The CDs/gel glasses show better transmittance in visible light bands and excellent thermal stability. A blue-pumped CDs/gel glasses phosphor-based trichromatic white light-emitting diode (WLED) is realized, whose color rendering index is 92.9. The WLED gets the highest luminous efficiency of 71.75 lm W -1 in CDs-based trichromatic WLEDs. This work opens a door for developing highly efficient green- and red-emissive switching CDs which were used as phosphors for WLEDs and have the tendency for applications in other fields, such as sensing, bioimaging, and photocatalysis.

Use of Cdse/ZnS quantum dots for sensitive detection and quantification of paraquat in water samples.

PubMed

Durán, Gema M; Contento, Ana M; Ríos, Ángel

2013-11-01

Based on the highly sensitive fluorescence change of water-soluble CdSe/ZnS core-shell quantum dots (QD) by paraquat herbicide, a simple, rapid and reproducible methodology was developed to selectively determine paraquat (PQ) in water samples. The methodology enabled the use of simple pretreatment procedure based on the simple water solubilization of CdSe/ZnS QDs with hydrophilic heterobifunctional thiol ligands, such as 3-mercaptopropionic acid (3-MPA), using microwave irradiation. The resulting water-soluble QDs exhibit a strong fluorescence emission at 596 nm with a high and reproducible photostability. The proposed analytical method thus satisfies the need for a simple, sensible and rapid methodology to determine residues of paraquat in water samples, as required by the increasingly strict regulations for health protection introduced in recent years. The sensitivity of the method, expressed as detection limits, was as low as 3.0 ng L(-1). The lineal range was between 10-5×10(3) ng L(-1). RSD values in the range of 71-102% were obtained. The analytical applicability of proposed method was demonstrated by analyzing water samples from different procedence. Copyright © 2013 Elsevier B.V. All rights reserved.

21 CFR 201.71 - Magnesium labeling.

Code of Federal Regulations, 2014 CFR

2014-04-01

... disease [bullet] a magnesium-restricted diet”. The warnings in §§ 201.64(c), 201.70(c), 201.71(c), and 201...., a magnesium or potassium-restricted diet. 1 See § 201.66(b)(4) of this chapter for definition of...

21 CFR 201.71 - Magnesium labeling.

Code of Federal Regulations, 2012 CFR

2012-04-01

... disease [bullet] a magnesium-restricted diet”. The warnings in §§ 201.64(c), 201.70(c), 201.71(c), and 201...., a magnesium or potassium-restricted diet. 1 See § 201.66(b)(4) of this chapter for definition of...

21 CFR 201.71 - Magnesium labeling.

Code of Federal Regulations, 2013 CFR

2013-04-01

... disease [bullet] a magnesium-restricted diet”. The warnings in §§ 201.64(c), 201.70(c), 201.71(c), and 201...., a magnesium or potassium-restricted diet. 1 See § 201.66(b)(4) of this chapter for definition of...

Do you see what I see? A comparative investigation of the Delboeuf illusion in humans (Homo sapiens), rhesus monkeys (Macaca mulatta), and capuchin monkeys (Cebus apella).

PubMed

Parrish, Audrey E; Brosnan, Sarah F; Beran, Michael J

2015-10-01

Studying visual illusions is critical to understanding typical visual perception. We investigated whether rhesus monkeys (Macaca mulatta) and capuchin monkeys (Cebus apella) perceived the Delboeuf illusion in a similar manner as human adults (Homo sapiens). To test this, in Experiment 1, we presented monkeys and humans with a relative discrimination task that required subjects to choose the larger of 2 central dots that were sometimes encircled by concentric rings. As predicted, humans demonstrated evidence of the Delboeuf illusion, overestimating central dots when small rings surrounded them and underestimating the size of central dots when large rings surrounded them. However, monkeys did not show evidence of the illusion. To rule out an alternate explanation, in Experiment 2, we presented all species with an absolute classification task that required them to classify a central dot as "small" or "large." We presented a range of ring sizes to determine whether the Delboeuf illusion would occur for any dot-to-ring ratios. Here, we found evidence of the Delboeuf illusion in all 3 species. Humans and monkeys underestimated central dot size to a progressively greater degree with progressively larger rings. The Delboeuf illusion now has been extended to include capuchin monkeys and rhesus monkeys, and through such comparative investigations we can better evaluate hypotheses regarding illusion perception among nonhuman animals. (c) 2015 APA, all rights reserved).

SnO2 quantum dots with rapid butane detection at lower ppm-level

NASA Astrophysics Data System (ADS)

Cai, Pan; Dong, Chengjun; Jiang, Ming; Shen, Yuanyuan; Tao, You; Wang, Yude

2018-04-01

SnO2 quantum dots (QDs) were successfully synthesized by a facile approach employing benzyl alcohol and ammonium hydroxide at lower temperature of 130 °C. It is revealed that the SnO2 QDs is about 3 nm in size to form clusters. The gas sensor based on SnO2 QDs shows a high potential for detecting low-ppm-level butane at 400 °C, exhibiting a high sensitivity, short response and rapid recovery time, and effective selectivity. The sensing mechanism is understood in terms of adsorbed oxygen species. Significantly, the excellent sensing performance is attributed to the smaller size of SnO2 and larger surface area (204.85 m2/g).

Composite materials with metal oxide attached to lead chalcogenide nanocrystal quantum dots with linkers

DOEpatents

Fuke, Nobuhiro; Koposov, Alexey Y; Sykora, Milan; Hoch, Laura

2014-12-16

Composite materials useful for devices such as photoelectrochemical solar cells include a substrate, a metal oxide film on the substrate, nanocrystalline quantum dots (NQDs) of lead sulfide, lead selenide, and lead telluride, and linkers that attach the NQDs to the metal oxide film. Suitable linkers preserve the 1s absorption peak of the NQDs. A suitable linker has a general structure A-B-C where A is a chemical group adapted for binding to a MO.sub.x and C is a chemical group adapted for binding to a NQD and B is a divalent, rigid, or semi-rigid organic spacer moiety. Other linkers that preserve the 1s absorption peak may also be used.

Report of the Aircraft Systems/Flight Test Workshop (1979) Aircraft Engineering Division, Systems and Flight Test Branches, held October 2 - 10, 1979, NASA/AMES Research Center, Moffett Field, CA

DTIC Science & Technology

1979-10-10

intercept the ILS at Allegheny County. The outside air temperature was +60 at 3000 feet. It was possible to perform the ILS approach within one dot...stMatr wW lrve of the Aru paca roferomd -L Zt* AMU taliax. JAM4 0. E8DLMSM cc: P-13Ol/13iA/1O/203/200/g-21-O/23/C-E’Ifl-4 no 0Ai3 ..c /2 .89 AGENDA ITEM...to intercept the ILS at Allegheny County. The outside air temperature was +60 at 3000 feet. It was possible to perform the ILS approach within one dot

Thermal management of microwave power heterojunction bipolar transistors

NASA Astrophysics Data System (ADS)

Bozada, C.; Cerny, C.; De Salvo, G.; Dettmer, R.; Ebel, J.; Gillespie, J.; Havasy, C.; Jenkins, T.; Ito, C.; Nakano, K.; Pettiford, C.; Quach, T.; Sewell, J.; Via, G. D.; Anholt, R.

1997-10-01

A comprehensive study of the device layout effects on thermal resistance in thermally-shunted heterojunction bipolar transistors (HBTs) was completed. The thermal resistance scales linearly with emitter dot diameter for single element HBTs. For multiple emitter element devices, the thermal resistance scales with area. HBTs with dot geometrics have lower thermal impedance than bar HBTs with equivalent emitter area. The thermal resistance of a 200 μm 2 emitter area device was reduced from 266°C/W to 146°C/W by increasing the shunt thickness from 3 μm to 20 μm and placing a thermal shunt landing between the fingers. Also, power-added efficiencies at 10 GHz were improved from 30% to 68% by this thermal resistance reduction.

Synthesis of Nitrogen and Sulfur Co-doped Carbon Dots from Garlic for Selective Detection of Fe3+

NASA Astrophysics Data System (ADS)

Sun, Chun; Zhang, Yu; Wang, Peng; Yang, Yue; Wang, Yu; Xu, Jian; Wang, Yiding; Yu, William W.

2016-02-01

Garlic was used as a green source to synthesize carbon dots (CDs) with a systematic study of the optical and structure properties. Ethylenediamine was added into the synthesis to improve the photoluminescence quantum yield (PL QY) of the CDs. Detailed structural and composition studies demonstrated that the content of N and the formation of C-N and C=N were critical to improve the PL QY. The as-synthesized CDs exhibited excellent stability in a wide pH range and high NaCl concentrations, rendering them applicable in complicated and harsh conditions. Quenching the fluorescence of the CDs in the presence of Fe3+ ion made these CDs a luminescent probe for selective detection of Fe3+ ion.

Synthesis of Nitrogen and Sulfur Co-doped Carbon Dots from Garlic for Selective Detection of Fe(3.).

PubMed

Sun, Chun; Zhang, Yu; Wang, Peng; Yang, Yue; Wang, Yu; Xu, Jian; Wang, Yiding; Yu, William W

2016-12-01

Garlic was used as a green source to synthesize carbon dots (CDs) with a systematic study of the optical and structure properties. Ethylenediamine was added into the synthesis to improve the photoluminescence quantum yield (PL QY) of the CDs. Detailed structural and composition studies demonstrated that the content of N and the formation of C-N and C=N were critical to improve the PL QY. The as-synthesized CDs exhibited excellent stability in a wide pH range and high NaCl concentrations, rendering them applicable in complicated and harsh conditions. Quenching the fluorescence of the CDs in the presence of Fe(3+) ion made these CDs a luminescent probe for selective detection of Fe(3+) ion.

Investigation of the optical characteristics of a combination of InP/ZnS-quantum dots with MWCNTs in a PMMA matrix

NASA Astrophysics Data System (ADS)

Landi, G.; Henninger, M.; De Girolamo del Mauro, A.; Borriello, C.; Di Luccio, T.; Neitzert, H. C.

2013-10-01

In the present study we investigated a combination of quantum dots with multi-walled carbon nanotubes as a possible future additive to the active layer of polymer solar cells. In this case the quantum dots should serve to enhance the long wavelength response of the solar cell, while the nanotubes enhance the charge carrier collection efficiency by favoring charge carrier separation and enhancement of the lateral conduction of the films. In order to clarify the interplay of the nanoparticles only, we deposited them into a non-conducting and transparent polymethyl-methalacrylate (PMMA) matrix. InP/ZnS quantum dots with an emission peak wavelength of 660 nm have been chosen in this study, because their addition can enhance the long wavelength response of conventional poly(3-hexylthiophene) (P3HT): phenyl-C61-butyric acid methyl ester (PCBM) bulk heterostructure polymer solar cells. In our study we kept the quantum dot concentration constant and varied the concentration of the carbon nanotubes (CNTs) in the deposited films. The characterization of the film morphology by scanning electron microscopy (SEM) imaging and of the optical properties by photoluminescence and transmittance revealed a rather complex interplay between nanotubes and quantum dots. In particular we found a strong quenching of the photoluminescence and an inhomogeneous CNT distribution for carbon nanotube concentrations exceeding 1%. The decrease in optical transmittance of the films with increasing CNT concentration is less pronounced, when quantum dots (QDs) are added. The optical transmittance in a wavelength range between 380 nm and 800 nm of the composites could be expressed empirically as a simple second order polynomial function.

Fluorescent carbon quantum dots synthesized by chemical vapor deposition: An alternative candidate for electron acceptor in polymer solar cells

NASA Astrophysics Data System (ADS)

Cui, Bo; Yan, Lingpeng; Gu, Huimin; Yang, Yongzhen; Liu, Xuguang; Ma, Chang-Qi; Chen, Yongkang; Jia, Husheng

2018-01-01

Excitation-wavelength-dependent blue-greenish fluorescent carbon quantum dots (CQDs) with graphite structure were synthesized by chemical vapor deposition (CVD) method. In comparison with those synthesized by hydrothermal method (named H-CQDs), C-CQDs have less hydrophilic terminal groups, showing good solubility in common organic solvents. Furthermore, these synthesized C-CQDs show a low LUMO energy level (LUMO = -3.84 eV), which is close to that of phenyl-C61-butyric acid methyl ester (PC61BM, LUMO = -4.01 eV), the most widely used electron acceptor in polymer solar cells. Photoluminescence quenching of the poly(3-hexylthiophene-2,5-diyl):C-CQDs blended film (P3HT:C-CQDs) indicated that a photo-induced charge transfer between P3HT and C-CQDs occurs in such a composite film. Bulk heterojunction solar cells using C-CQDs as electron acceptors or doping materials were fabricated and tested. High fill factors were achieved for these C-CQDs based polymer solar cells, demonstrating that CQDs synthesized by CVD could be alternative to the fullerene derivatives for applying in polymer solar cells.

Attachment of Quantum Dots on Zinc Oxide Nanorods

NASA Astrophysics Data System (ADS)

Seay, Jared; Liang, Huan; Harikumar, Parameswar

2011-03-01

ZnO nanorods grown by hydrothermal technique are of great interest for potential applications in photovoltaic and optoelectronic devices. In this study we investigate the optimization of the optical absorption properties by a low temperature, chemical bath deposition technique. Our group fabricated nanorods on indium tin oxide (ITO) substrate with precursor solution of zinc nitrate hexahydrate and hexamethylenetramine (1:1 molar ratio) at 95C for 9 hours. In order to optimize the light absorption characteristics of ZnO nanorods, CdSe/ZnS core-shell quantum dots (QDs) of various diameters were attached to the surface of ZnO nanostructures grown on ITO and gold-coated silicon substrates. Density of quantum dots was varied by controlling the number drops on the surface of the ZnO nanorods. For a 0.1 M concentration of QDs of 10 nm diameter, the PL intensity at 385 nm increased as the density of the quantum dots on ZnO nanostructures was increased. For quantum dots at 1 M concentration, the PL intensity at 385 nm increased at the beginning and then decreased at higher density. We will discuss the observed changes in PL intensity with QD concentration with ZnO-QD band structure and recombination-diffusion processes taking place at the interface.

Voltage-controlled quantum light from an atomically thin semiconductor

NASA Astrophysics Data System (ADS)

Chakraborty, Chitraleema; Kinnischtzke, Laura; Goodfellow, Kenneth M.; Beams, Ryan; Vamivakas, A. Nick

2015-06-01

Although semiconductor defects can often be detrimental to device performance, they are also responsible for the breadth of functionality exhibited by modern optoelectronic devices. Artificially engineered defects (so-called quantum dots) or naturally occurring defects in solids are currently being investigated for applications ranging from quantum information science and optoelectronics to high-resolution metrology. In parallel, the quantum confinement exhibited by atomically thin materials (semi-metals, semiconductors and insulators) has ushered in an era of flatland optoelectronics whose full potential is still being articulated. In this Letter we demonstrate the possibility of leveraging the atomically thin semiconductor tungsten diselenide (WSe2) as a host for quantum dot-like defects. We report that this previously unexplored solid-state quantum emitter in WSe2 generates single photons with emission properties that can be controlled via the application of external d.c. electric and magnetic fields. These new optically active quantum dots exhibit excited-state lifetimes on the order of 1 ns and remarkably large excitonic g-factors of 10. It is anticipated that WSe2 quantum dots will provide a novel platform for integrated solid-state quantum photonics and quantum information processing, as well as a rich condensed-matter physics playground with which to explore the coupling of quantum dots and atomically thin semiconductors.

Black Hole Disk Accretion in Supernovae

NASA Astrophysics Data System (ADS)

Nomura, H.; Mineshige, S.; Hirose, M.; Nomoto, K.; Suzuki, T.

Hydrodynamical disk accretion flow onto a new-born black hole in a supernova is studied using the SPH (Smoothed Particle Hydrodynamics) method. It has been suggested that a mass of ~0.1Modot falls back to a black hole by a reverse shock. If the progenitor was rotating before the explosion, the accreting material should have a certain amount of angular momentum, thus forming an accretion disk. Disk material will eventually accrete towards the central object via viscosity with a supercritical accretion rate, dotM / dotMc > 106, for first several tens of days. (Here, dotMc is the Eddington luminosity divided by c2.) We then expect that such an accretion disk is optically thick and advection-dominated; that is, the disk is so hot that produced energy and photons are advected inward rather than being radiated away. Thus, the disk luminosity is much less than the Eddington luminosity (~1038erg s-1). The disk becomes hot and dense; for dotM / dotMc ~106 and the viscosity parameter alphavis ~0.01, for example, T ~109K and rho ~103gcm-3 in the vicinity of the central object. Efficient nucleosynthesis is hence expected even for reasonable viscosity magnitudes, although produced elements may be swallowed by the black hole.

Measurement of the spin temperature of optically cooled nuclei and GaAs hyperfine constants in GaAs/AlGaAs quantum dots

NASA Astrophysics Data System (ADS)

Chekhovich, E. A.; Ulhaq, A.; Zallo, E.; Ding, F.; Schmidt, O. G.; Skolnick, M. S.

2017-10-01

Deep cooling of electron and nuclear spins is equivalent to achieving polarization degrees close to 100% and is a key requirement in solid-state quantum information technologies. While polarization of individual nuclear spins in diamond and SiC (ref. ) reaches 99% and beyond, it has been limited to 50-65% for the nuclei in quantum dots. Theoretical models have attributed this limit to formation of coherent `dark' nuclear spin states but experimental verification is lacking, especially due to the poor accuracy of polarization degree measurements. Here we measure the nuclear polarization in GaAs/AlGaAs quantum dots with high accuracy using a new approach enabled by manipulation of the nuclear spin states with radiofrequency pulses. Polarizations up to 80% are observed--the highest reported so far for optical cooling in quantum dots. This value is still not limited by nuclear coherence effects. Instead we find that optically cooled nuclei are well described within a classical spin temperature framework. Our findings unlock a route for further progress towards quantum dot electron spin qubits where deep cooling of the mesoscopic nuclear spin ensemble is used to achieve long qubit coherence. Moreover, GaAs hyperfine material constants are measured here experimentally for the first time.

Simple Identification of Human Taenia Species by Multiplex Loop-Mediated Isothermal Amplification in Combination with Dot Enzyme-Linked Immunosorbent Assay.

PubMed

Nkouawa, Agathe; Sako, Yasuhito; Okamoto, Munehiro; Ito, Akira

2016-06-01

For differential detection of Taenia solium, Taenia saginata, and Taenia asiatica, loop-mediated isothermal amplification (LAMP) assay targeting the cytochrome c oxidase subunit 1 gene has been recently developed and shown to be sensitive, specific, and effective. However, to achieve differential identification, one specimen requires three reaction mixtures containing a primer set of each Taenia species separately, which is complex and time consuming and increases the risk of cross-contamination. In this study, we developed a simple differential identification of human Taenia species using multiplex LAMP (mLAMP) in combination with dot enzyme-linked immunosorbent assay (dot-ELISA). Forward inner primers of T. solium, T. saginata, and T. asiatica labeled with fluorescein isothiocyanate (FITC), digoxigenin (DIG), and tetramethylrhodamine (TAMRA), respectively, and biotin-labeled backward inner primers were used in mLAMP. The mLAMP assay succeeded in specific amplification of each respective target gene in a single tube. Furthermore, the mLAMP product from each species was easily distinguished by dot-ELISA with an antibody specific for FITC, DIG, or TAMRA. The mLAMP assay in combination with dot-ELISA will make identification of human Taenia species simpler, easier, and more practical. © The American Society of Tropical Medicine and Hygiene.

ISO(4,1) symmetry in the EFT of inflation

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

Creminelli, Paolo; Emami, Razieh; Simonović, Marko

In DBI inflation the cubic action is a particular linear combination of the two, otherwise independent, cubic operators π-dot {sup 3} and π-dot (∂{sub i}π){sup 2}. We show that in the Effective Field Theory (EFT) of inflation this is a consequence of an approximate 5D Poincar and apos;e symmetry, ISO(4,1), non-linearly realized by the Goldstone π. This symmetry uniquely fixes, at lowest order in derivatives, all correlation functions in terms of the speed of sound c{sub s}. In the limit c{sub s} → 1, the ISO(4,1) symmetry reduces to the Galilean symmetry acting on π. On the other hand, wemore » point out that the non-linear realization of SO(4,2), the isometry group of 5D AdS space, does not fix the cubic action in terms of c{sub s}.« less

Synthesis and Characterization of Chalcopyrite (CuInS2 and CuhInSe2) Colloidal Nanoparticles for Optoelectronic Applications via Low-Temperature Pyrolysis of Single-Source Precursors

NASA Technical Reports Server (NTRS)

Castro, S. L.; Bailey, S. G.; Raffaelle, R. P.; Banger, K. K.; Fahey, Stephen; Hepp, A. F.

2003-01-01

Nanocrystalline (or quantum dot) materials hold potential as components of next-generation photovoltaic (PV) devices. The inclusion of quantum dots in PV devices has been proposed as a means to improve the efficiency of photon conversion (quantum dot solar cell), enable low-cost deposition of thin-films, provide sites for exciton dissociation, and pathways for electron transport. Quantum dots are also expected to be more resistant to degradation from electron, proton, and alpha particle radiation than the corresponding bulk material, a requirement for use in space solar sells. Chalcopyrite nanocrystals can be produced by low-temperature thermal decomposition of single-source precursors such as (PR3)2CuIn(ER')4 (R = Ph, R' = Et, E = S; R = R' = Ph, E = Se). Single-source precursors are molecules which contain all the necessary elements for synthesis of a desired material. Thermal decomposition of the precursor results in the formation of material with the correct stoichiometry as a nanocrystalline powder or a thin film, often at significantly lower temperatures than those typically employed for thin-film deposition by multi-source evaporation techniques, typically less than 500 C. We show that CuInSz and CuInSe2 nanocrystals can be synthesized from the precursors at temperatures as low as 250 C. The nanocrystals are characterized by optical spectroscopy, X-ray diffraction, and electron microscopy.

PCR colorimetric dot-blot assay and clinical pretest probability for diagnosis of Pulmonary Tuberculosis in Smear-Negative patients

PubMed Central

Scherer, Luciene Cardoso; Sperhacke, Rosa Dea; Jarczewski, Carla; Cafrune, Patrícia I; Minghelli, Simone; Ribeiro, Marta Osório; Mello, Fernanda CQ; Ruffino-Netto, Antonio; Rossetti, Maria LR; Kritski, Afrânio L

2007-01-01

Background Smear-negative pulmonary tuberculosis (SNPTB) accounts for 30% of Pulmonary Tuberculosis (PTB) cases reported annually in developing nations. Polymerase chain reaction (PCR) may provide an alternative for the rapid detection of Mycobacterium tuberculosis (MTB); however little data are available regarding the clinical utility of PCR in SNPTB, in a setting with a high burden of TB/HIV co-infection. Methods To evaluate the performance of the PCR dot-blot in parallel with pretest probability (Clinical Suspicion) in patients suspected of having SNPTB, a prospective study of 213 individuals with clinical and radiological suspicion of SNPTB was carried out from May 2003 to May 2004, in a TB/HIV reference hospital. Respiratory specialists estimated the pretest probability of active disease into high, intermediate, low categories. Expectorated sputum was examined by direct microscopy (Ziehl-Neelsen staining), culture (Lowenstein Jensen) and PCR dot-blot. Gold standard was based on culture positivity combined with the clinical definition of PTB. Results In smear-negative and HIV subjects, active PTB was diagnosed in 28.4% (43/151) and 42.2% (19/45), respectively. In the high, intermediate and low pretest probability categories active PTB was diagnosed in 67.4% (31/46), 24% (6/25), 7.5% (6/80), respectively. PCR had sensitivity of 65% (CI 95%: 50%–78%) and specificity of 83% (CI 95%: 75%–89%). There was no difference in the sensitivity of PCR in relation to HIV status. PCR sensitivity and specificity among non-previously TB treated and those treated in the past were, respectively: 69%, 43%, 85% and 80%. The high pretest probability, when used as a diagnostic test, had sensitivity of 72% (CI 95%:57%–84%) and specificity of 86% (CI 95%:78%–92%). Using the PCR dot-blot in parallel with high pretest probability as a diagnostic test, sensitivity, specificity, positive and negative predictive values were: 90%, 71%, 75%, and 88%, respectively. Among non-previously TB treated and HIV subjects, this approach had sensitivity, specificity, positive and negative predictive values of 91%, 79%, 81%, 90%, and 90%, 65%, 72%, 88%, respectively. Conclusion PCR dot-blot associated with a high clinical suspicion may provide an important contribution to the diagnosis of SNPTB mainly in patients that have not been previously treated attended at a TB/HIV reference hospital. PMID:18096069

A Pt-Co3O4-CD electrocatalyst with enhanced electrocatalytic performance and resistance to CO poisoning achieved by carbon dots and Co3O4 for direct methanol fuel cells.

PubMed

Sun, Yue; Zhou, Yunjie; Zhu, Cheng; Hu, Lulu; Han, Mumei; Wang, Aoqi; Huang, Hui; Liu, Yang; Kang, Zhenhui

2017-05-04

Highly efficient electrocatalysts remain huge challenges in direct methanol fuel cells (DMFCs). Here, a Pt-Co 3 O 4 -CDs/C composite was fabricated as an anode electrocatalyst with low Pt content (12 wt%) by using carbon dots (CDs) and Co 3 O 4 nanoparticles as building blocks. The Pt-Co 3 O 4 -CDs/C composite catalyst shows a significantly enhanced electrocatalytic activity (1393.3 mA mg -1 Pt), durability (over 4000 s) and CO-poisoning tolerance. The superior catalytic activity should be attributed to the synergistic effect of CDs, Pt and Co 3 O 4 . Furthermore, the Pt-Co 3 O 4 -CDs/C catalyst was integrated into a single cell, which exhibits a maximum power density of 45.6 mW cm -2 , 1.7 times the cell based on the commercial 20 wt% Pt/C catalyst.

Synthesis of a Neutral Mixed-Valence Diferrocenyl Carborane for Molecular Quantum-Dot Cellular Automata Applications.

PubMed

Christie, John A; Forrest, Ryan P; Corcelli, Steven A; Wasio, Natalie A; Quardokus, Rebecca C; Brown, Ryan; Kandel, S Alex; Lu, Yuhui; Lent, Craig S; Henderson, Kenneth W

2015-12-14

The preparation of 7-Fc(+) -8-Fc-7,8-nido-[C2 B9 H10 ](-) (Fc(+) FcC2 B9 (-) ) demonstrates the successful incorporation of a carborane cage as an internal counteranion bridging between ferrocene and ferrocenium units. This neutral mixed-valence Fe(II) /Fe(III) complex overcomes the proximal electronic bias imposed by external counterions, a practical limitation in the use of molecular switches. A combination of UV/Vis-NIR spectroscopic and TD-DFT computational studies indicate that electron transfer within Fc(+) FcC2 B9 (-) is achieved through a bridge-mediated mechanism. This electronic framework therefore provides the possibility of an all-neutral null state, a key requirement for the implementation of quantum-dot cellular automata (QCA) molecular computing. The adhesion, ordering, and characterization of Fc(+) FcC2 B9 (-) on Au(111) has been observed by scanning tunneling microscopy. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Transcriptional and metabolic response of recombinant Escherichia coli to spatial dissolved oxygen tension gradients simulated in a scale-down system.

PubMed

Lara, Alvaro R; Leal, Lidia; Flores, Noemí; Gosset, Guillermo; Bolívar, Francisco; Ramírez, Octavio T

2006-02-05

Escherichia coli, expressing recombinant green fluorescent protein (GFP), was subjected to dissolved oxygen tension (DOT) oscillations in a two-compartment system for simulating gradients that can occur in large-scale bioreactors. Cells were continuously circulated between the anaerobic (0% DOT) and aerobic (10% DOT) vessels of the scale-down system to mimic an overall circulation time of 50 s, and a mean residence time in the anaerobic and aerobic compartments of 33 and 17 s, respectively. Transcription levels of mixed acid fermentation genes (ldhA, poxB, frdD, ackA, adhE, pflD, and fdhF), measured by quantitative RT-PCR, increased between 1.5- to over 6-fold under oscillatory DOT compared to aerobic cultures (constant 10% DOT). In addition, the transcription level of fumB increased whereas it decreased for sucA and sucB, suggesting that the tricarboxylic acid cycle was functioning as two open branches. Gene transcription levels revealed that cytrochrome bd, which has higher affinity to oxygen but lower energy efficiency, was preferred over cytochrome bO3 in oscillatory DOT cultures. Post-transcriptional processing limited heterologous protein production in the scale-down system, as inferred from similar gfp transcription but 19% lower GFP concentration compared to aerobic cultures. Simulated DOT gradients also affected the transcription of genes of the glyoxylate shunt (aceA), of global regulators of aerobic and anaerobic metabolism (fnr, arcA, and arcB), and other relevant genes (luxS, sodA, fumA, and sdhB). Transcriptional changes explained the observed alterations in overall stoichiometric and kinetic parameters, and production of ethanol and organic acids. Differences in transcription levels between aerobic and anaerobic compartments were also observed, indicating that E. coli can respond very fast to intermittent DOT conditions. The transcriptional responses of E. coli to DOT gradients reported here are useful for establishing rational scale-up criteria and strain design strategies for improved culture performance at large scales. (c) 2005 Wiley Periodicals, Inc.