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Xu DD, Vong AF, Utama MIB, Lebedev D, Ananth R, Hersam MC, Weiss EA, Mirkin CA. Sub-Diffraction Correlation of Quantum Emitters and Local Strain Fields in Strain-Engineered WSe 2 Monolayers. Adv Mater 2024:e2314242. [PMID: 38346232 DOI: 10.1002/adma.202314242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Indexed: 03/27/2024]
Abstract
Strain-engineering in atomically thin metal dichalcogenides is a useful method for realizing single-photon emitters (SPEs) for quantum technologies. Correlating SPE position with local strain topography is challenging due to localization inaccuracies from the diffraction limit. Currently, SPEs are assumed to be positioned at the highest strained location and are typically identified by randomly screening narrow-linewidth emitters, of which only a few are spectrally pure. In this work, hyperspectral quantum emitter localization microscopy is used to locate 33 SPEs in nanoparticle-strained WSe2 monolayers with sub-diffraction-limit resolution (≈30 nm) and correlate their positions with the underlying strain field via image registration. In this system, spectrally pure emitters are not concentrated at the highest strain location due to spectral contamination; instead, isolable SPEs are distributed away from points of peak strain with an average displacement of 240 nm. These observations point toward a need for a change in the design rules for strain-engineered SPEs and constitute a key step toward realizing next-generation quantum optical architectures.
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Affiliation(s)
- David D Xu
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
- International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
| | - Albert F Vong
- International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
- Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, IL, 60208, USA
| | - M Iqbal Bakti Utama
- Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, IL, 60208, USA
| | - Dmitry Lebedev
- Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, IL, 60208, USA
| | - Riddhi Ananth
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
- International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
| | - Mark C Hersam
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
- International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
- Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, IL, 60208, USA
- Department of Electrical and Computer Engineering, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
| | - Emily A Weiss
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
- International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
- Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, IL, 60208, USA
| | - Chad A Mirkin
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
- International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
- Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, IL, 60208, USA
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Rawat A, Clark L, Zhang C, Cavin J, Sangwan VK, Toth PS, Janáky C, Ananth R, Goldfine E, Bedzyk MJ, Weiss EA, Rondinelli JM, Hersam MC, Meletis EI, Rajeshwar K. Solution Combustion Synthesis and Characterization of Magnesium Copper Vanadates. Inorg Chem 2023. [PMID: 37260199 DOI: 10.1021/acs.inorgchem.3c00452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Magnesium vanadate (MgV2O6) and its alloys with copper vanadate were synthesized via the solution combustion technique. Phase purity and solid solution formation were confirmed by a variety of experimental techniques, supported by electronic structure simulations based on density functional theory (DFT). Powder X-ray diffraction combined with Rietveld refinement, laser Raman spectroscopy, diffuse reflectance spectroscopy, and high-resolution transmission electron microscopy showed single-phase alloy formation despite the MgV2O6 and CuV2O6 end members exhibiting monoclinic and triclinic crystal systems, respectively. DFT-calculated optical band gaps showed close agreement in the computed optical bandgaps with experimentally derived values. Surface photovoltage spectroscopy, ambient-pressure photoemission spectroscopy, and Kelvin probe contact potential difference (work function) measurements confirmed a systematic variation in the optical bandgap modification and band alignment as a function of stoichiometry in the alloy composition. These data indicated n-type semiconductor behavior for all the samples which was confirmed by photoelectrochemical measurements.
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Affiliation(s)
- Abhishek Rawat
- Department of Chemistry & Biochemistry, The University of Texas at Arlington, Arlington, Texas 76019, United States
| | - Laura Clark
- Department of Mechanical and Aerospace Engineering, The University of Texas at Arlington, Arlington, Texas 76019, United States
| | - Chuzhong Zhang
- Department of Materials Science and Engineering, The University of Texas at Arlington, Arlington, Texas 76019, United States
| | - John Cavin
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Vinod K Sangwan
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Peter S Toth
- Department of Physical Chemistry and Materials Science, University of Szeged, Rerrich Square 1, Szeged H-6720, Hungary
| | - Csaba Janáky
- Department of Physical Chemistry and Materials Science, University of Szeged, Rerrich Square 1, Szeged H-6720, Hungary
| | - Riddhi Ananth
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Elise Goldfine
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Michael J Bedzyk
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Emily A Weiss
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - James M Rondinelli
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Mark C Hersam
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Efstathios I Meletis
- Department of Materials Science and Engineering, The University of Texas at Arlington, Arlington, Texas 76019, United States
| | - Krishnan Rajeshwar
- Department of Chemistry & Biochemistry, The University of Texas at Arlington, Arlington, Texas 76019, United States
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Utama MIB, Zeng H, Sadhukhan T, Dasgupta A, Gavin SC, Ananth R, Lebedev D, Wang W, Chen JS, Watanabe K, Taniguchi T, Marks TJ, Ma X, Weiss EA, Schatz GC, Stern NP, Hersam MC. Chemomechanical modification of quantum emission in monolayer WSe 2. Nat Commun 2023; 14:2193. [PMID: 37069140 PMCID: PMC10110606 DOI: 10.1038/s41467-023-37892-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2023] [Accepted: 04/04/2023] [Indexed: 04/19/2023] Open
Abstract
Two-dimensional (2D) materials have attracted attention for quantum information science due to their ability to host single-photon emitters (SPEs). Although the properties of atomically thin materials are highly sensitive to surface modification, chemical functionalization remains unexplored in the design and control of 2D material SPEs. Here, we report a chemomechanical approach to modify SPEs in monolayer WSe2 through the synergistic combination of localized mechanical strain and noncovalent surface functionalization with aryl diazonium chemistry. Following the deposition of an aryl oligomer adlayer, the spectrally complex defect-related emission of strained monolayer WSe2 is simplified into spectrally isolated SPEs with high single-photon purity. Density functional theory calculations reveal energetic alignment between WSe2 defect states and adsorbed aryl oligomer energy levels, thus providing insight into the observed chemomechanically modified quantum emission. By revealing conditions under which chemical functionalization tunes SPEs, this work broadens the parameter space for controlling quantum emission in 2D materials.
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Affiliation(s)
- M Iqbal Bakti Utama
- Department of Materials Science and Engineering and the Materials Research Center, Northwestern University, Evanston, IL, 60208, USA
| | - Hongfei Zeng
- Department of Physics and Astronomy, Northwestern University, Evanston, IL, 60208, USA
| | - Tumpa Sadhukhan
- Department of Chemistry and the Materials Research Center, Northwestern University, Evanston, IL, 60208, USA
- Department of Chemistry, SRM Institute of Science and Technology, Kattankulathur, Tamil Nadu, 603203, India
| | - Anushka Dasgupta
- Department of Materials Science and Engineering and the Materials Research Center, Northwestern University, Evanston, IL, 60208, USA
| | - S Carin Gavin
- Department of Physics and Astronomy, Northwestern University, Evanston, IL, 60208, USA
| | - Riddhi Ananth
- Department of Chemistry and the Materials Research Center, Northwestern University, Evanston, IL, 60208, USA
| | - Dmitry Lebedev
- Department of Materials Science and Engineering and the Materials Research Center, Northwestern University, Evanston, IL, 60208, USA
| | - Wei Wang
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Jia-Shiang Chen
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, IL, 60439, USA
- Northwestern-Argonne Institute of Science and Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - Tobin J Marks
- Department of Materials Science and Engineering and the Materials Research Center, Northwestern University, Evanston, IL, 60208, USA
- Department of Chemistry and the Materials Research Center, Northwestern University, Evanston, IL, 60208, USA
| | - Xuedan Ma
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, IL, 60439, USA
- Northwestern-Argonne Institute of Science and Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Emily A Weiss
- Department of Chemistry and the Materials Research Center, Northwestern University, Evanston, IL, 60208, USA
| | - George C Schatz
- Department of Chemistry and the Materials Research Center, Northwestern University, Evanston, IL, 60208, USA.
| | - Nathaniel P Stern
- Department of Physics and Astronomy, Northwestern University, Evanston, IL, 60208, USA.
| | - Mark C Hersam
- Department of Materials Science and Engineering and the Materials Research Center, Northwestern University, Evanston, IL, 60208, USA.
- Department of Chemistry and the Materials Research Center, Northwestern University, Evanston, IL, 60208, USA.
- Department of Electrical and Computer Engineering, Northwestern University, Evanston, IL, 60208, USA.
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Xu DD, Vong AF, Lebedev D, Ananth R, Wong AM, Brown PT, Hersam MC, Mirkin CA, Weiss EA. Conversion of Classical Light Emission from a Nanoparticle-Strained WSe 2 Monolayer into Quantum Light Emission via Electron Beam Irradiation. Adv Mater 2023; 35:e2208066. [PMID: 36373540 DOI: 10.1002/adma.202208066] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 10/19/2022] [Indexed: 06/16/2023]
Abstract
Solid-state single photon emitters (SPEs) within atomically thin transition metal dichalcogenides (TMDs) have recently attracted interest as scalable quantum light sources for quantum photonic technologies. Among TMDs, WSe2 monolayers (MLs) are promising for the deterministic fabrication and engineering of SPEs using local strain fields. The ability to reliably produce isolatable SPEs in WSe2 is currently impeded by the presence of numerous spectrally overlapping states that occur at strained locations. Here nanoparticle (NP) arrays with precisely defined positions and sizes are employed to deterministically create strain fields in WSe2 MLs, thus enabling the systematic investigation and control of SPE formation. Using this platform, electron beam irradiation at NP-strained locations transforms spectrally overlapped sub-bandgap emission states into isolatable, anti-bunched quantum emitters. The dependence of the emission spectra of WSe2 MLs as a function of strain magnitude and exposure time to electron beam irradiation is quantified and provides insight into the mechanism for SPE production. Excitons selectively funnel through strongly coupled sub-bandgap states introduced by electron beam irradiation, which suppresses spectrally overlapping emission pathways and leads to measurable anti-bunched behavior. The findings provide a strategy to generate isolatable SPEs in 2D materials with a well-defined energy range.
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Affiliation(s)
- David D Xu
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
- International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
| | - Albert F Vong
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
| | - Dmitry Lebedev
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
| | - Riddhi Ananth
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
| | - Alexa M Wong
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
- International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
| | - Paul T Brown
- Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, IL, 60208, USA
| | - Mark C Hersam
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
- Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, IL, 60208, USA
| | - Chad A Mirkin
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
- International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
- Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, IL, 60208, USA
| | - Emily A Weiss
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
- Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, IL, 60208, USA
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Hinnant K, Giles S, Ananth R, Miller J. Exploring Synergistic Fire Suppression of Siloxane-Glycoside Firefighting Foam using Sulfonated Hydrotrope Additives to Alter Surfactant Aggregation in Solution. Colloids Surf A Physicochem Eng Asp 2022. [DOI: 10.1016/j.colsurfa.2022.130219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Zeng Y, Ananth R, Dill TJ, Rodarte A, Rozin MJ, Bradshaw N, Brown ER, Tao AR. Metasurface-Enhanced Raman Spectroscopy (mSERS) for Oriented Molecular Sensing. ACS Appl Mater Interfaces 2022; 14:32598-32607. [PMID: 35816614 DOI: 10.1021/acsami.2c01656] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Surface-enhanced Raman spectroscopy (SERS) is a widely used sensing technique for ultrasensitivity chemical sensing, biomedical detection, and environmental analysis. Because SERS signal is proportional to the fourth power of the local electric field, several SERS applications have focused on the design of plasmonic nanogaps to take advantage of the extremely strong near-field enhancement that results from plasmonic coupling, but few designs have focused on how SERS detection is affected by molecular orientation within these nanogaps. Here, we demonstrate a nanoparticle-on-metal metasurface designed for near-perfect optical absorption as a platform for Raman detection of highly oriented molecular analytes, including two-dimensional materials and aromatic molecules. This metasurface platform overcomes challenges in nanoparticle aggregation, which commonly leads to low or fluctuating Raman signals in other colloidal nanoparticle platforms. Our metasurface-enhanced Raman spectroscopy (mSERS) platform is based on a colloidal Langmuir-Schaefer deposition, with up to 32% surface coverage density of nanogaps across an entire sensor chip. In this work, we perform both simulations of the local electric field and experimental characterization of the mSERS signal obtained for oriented molecular layers. We then demonstrate this mSERS platform for the quantitative detection of the drinking-water toxin polybrominated diphenyl ether (BDE-15), with a limit of detection of 0.25 μM under 530 μW excitation. This detection limit is comparable to other SERS-based sensors operating at laser powers over 3 orders of magnitude higher, indicating the promise of our mSERS platform for nondestructive and low-level analyte detection.
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Affiliation(s)
- Yuan Zeng
- Department of NanoEngineering, University of California, San Diego, 9500 Gilman Drive MC 0448, La Jolla, California 92093-0448, United States
- Materials Science and Engineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Riddhi Ananth
- Department of Chemistry & Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Tyler J Dill
- Department of NanoEngineering, University of California, San Diego, 9500 Gilman Drive MC 0448, La Jolla, California 92093-0448, United States
| | - Andrea Rodarte
- Department of NanoEngineering, University of California, San Diego, 9500 Gilman Drive MC 0448, La Jolla, California 92093-0448, United States
| | - Matthew J Rozin
- Department of NanoEngineering, University of California, San Diego, 9500 Gilman Drive MC 0448, La Jolla, California 92093-0448, United States
- Materials Science and Engineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Nathan Bradshaw
- Department of NanoEngineering, University of California, San Diego, 9500 Gilman Drive MC 0448, La Jolla, California 92093-0448, United States
| | - Eric R Brown
- Department of NanoEngineering, University of California, San Diego, 9500 Gilman Drive MC 0448, La Jolla, California 92093-0448, United States
| | - Andrea R Tao
- Department of NanoEngineering, University of California, San Diego, 9500 Gilman Drive MC 0448, La Jolla, California 92093-0448, United States
- Materials Science and Engineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
- Department of Chemistry & Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
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Gallagher RS, Ananth R, Granger K, Bradley B, Anderson JV, Fuerst EP. Phenolic and short-chained aliphatic organic acid constituents of wild oat (Avena fatua L.) seeds. J Agric Food Chem 2010; 58:218-225. [PMID: 20017486 DOI: 10.1021/jf9038106] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The objective of this research was to identify and quantify the phenolic and short-chained aliphatic organic acids present in the seeds of three wild-type populations of wild oat and compare these results to the chemical composition of seeds from two commonly utilized wild oat isolines (M73 and SH430). Phenolic acids have been shown to serve as germination inhibitors, as well as protection for seeds from biotic and abiotic stress factors in other species, whereas aliphatic organic acids have been linked to germination traits and protection against pathogens. Wild oat populations were grown under a "common garden" environment to remove maternal variation, and the resulting seeds were extracted to remove the readily soluble and chemically bound phenolic and aliphatic organic acid components. Compounds were identified and quantified using gas chromatography-mass spectrometry. Ferulic and p-coumaric acid comprised 99% of the total phenolic acids present in the seeds, of which 91% were contained in the hulls and 98% were in the chemically bound forms. Smaller quantities of OH benzoic and vanillic acid were also detected. Soluble organic acids concentrations were higher in the M73 isoline compared to SH430, suggesting that these chemical constituents could be related to seed dormancy. Malic, succinic, fumaric and azelaic acid were the dominant aliphatic organic acids detected in all seed and chemical fractions.
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Affiliation(s)
- R S Gallagher
- Department of Crop and Soil Sciences, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
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Ananth R, John Kirub J, Priyadarsh M, Albert A. Isolation of Newcastle Disease Viruses of High Virulence in Unvaccinated Healthy Village Chickens in South India. ACTA ACUST UNITED AC 2008. [DOI: 10.3923/ijps.2008.368.373] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Schulman JH, Mobley JP, Wolfe J, Regev E, Perron CY, Ananth R, Matei E, Glukhovsky A, Davis R. Battery powered BION FES network. Conf Proc IEEE Eng Med Biol Soc 2007; 2004:4283-6. [PMID: 17271251 DOI: 10.1109/iembs.2004.1404193] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The Alfred Mann Foundation is completing development of a coordinated network of BION microstimulator/sensor (hereinafter implant) that has broad stimulating, sensing and communication capabilities. The network consists of a master control unit (MCU) in communication with a group of BION implants. Each implant is powered by a custom lithium-ion rechargeable 10 mW-hr battery. The charging, discharging, safety, stimulating, sensing, and communication circuits are designed to be highly efficient to minimize energy use and maximize battery life and time between charges. The stimulator can be programmed to deliver pulses in any value in the following range: 5 microA to 20 mA in 3.3% constant current steps, 7 micros to 2000 micros in 7 micros pulse width steps, and 1 to 4000 Hz in frequency. The preamp voltage sensor covers the range 10 microV to 1.0 V with bandpass filtering and several forms of data analysis. The implant also contains sensors that can read out pressure, temperature, DC magnetic field, and distance (via a low frequency magnetic field) up to 20 cm between any two BION implants. The MCU contains a microprocessor, user interface, two-way communication system, and a rechargeable battery. The MCU can command and interrogate in excess of 800 BlON implants every 10 ms, i.e., 100 times a second.
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Ananth R. Downstaging of cervical cancer. J Indian Med Assoc 2000; 98:41-4. [PMID: 11016148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Globally cervical cancer is the fifth most common cancer and of estimated 460,000 new cases each year three quarters occur in developing countries. In India annually 16% of the world's total cases occur and only 5% are reported in the early stages. Downstaging is defined as a process of screening for cancer using clinical approaches for early detection of this disease. This is distinct from screening test and results in detection of the disease at a less advanced stage in the absence of screening. This experimental approach is applicable in developing countries where cytological screening is not possible in the near future. In this method paramedical staff trained for minimum period will be able to identify any abnormality including suspicious cervix and refer the case early to centres where facilities exist for treatment of premalignant and malignant lesions, including educating the women regarding risk factors, symptoms of the disease and prophylaxis. This experimental methodology recommended by WHO for developing countries like India has to be evaluated by monitoring various ongoing projects where visual inspection screening method is used. The results are collected which include feasibility, compliance, costing, referral methodology, difficulties in implementation, specificity, sensitivity, positive predictive value and drawbacks. The methodology of visual inspection and modified aided visual inspection, frequency and results of various studies in the Indian scenario is for recommendation of downstaging in MCH care. This is to be implemented in rural areas taking into consideration their cultural background and available infrastructure since cytology screening is not possible to cover even 20% of the existing cases in the near future.
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Gajalakshmi CK, Krishnamurthi S, Ananth R, Shanta V. Cervical cancer screening in Tamilnadu, India: a feasibility study of training the village health nurse. Cancer Causes Control 1996; 7:520-4. [PMID: 8877049 DOI: 10.1007/bf00051884] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Uterine cervical cancer is the most common malignancy among females in developing countries, including India. The success of cervical cancer screening programs in North America and Western Europe has been the result of centralized cervical-cytology screening. This is not possible in the villages (n = 17,000) of Tamilnadu where 58 percent of females in rural areas are illiterate, health infrastructure is mediocre, and cervical cytology is unknown. The present study was undertaken to examine if the village health nurse (VHN) could be trained quickly to identify a cervical abnormality by visual inspection so that we could 'down stage' the cancer to earlier stages, more amenable to treatment. VHNs also would be trained to take an adequate Pap smear. A total of 101 VHNs were trained in batches and returned to their villages. Within two years, 6,459 eligible women in the study area were screened. The agreement between the gynecologists and the VHNs in identifying cancer among those with abnormal cervix was 95 percent, and 80 percent of the Pap smears taken by VHNs were adequate by WHO criteria, making the feasibility study highly successful.
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Ananth R, Koo KK, Gill WN. Comment on "Surface-tension-anisotropy measurements of succinonitrile and pivalic acid: Comparison with microscopic solvability theory". Phys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics 1993; 48:2319-2320. [PMID: 9960857 DOI: 10.1103/physreve.48.2319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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13
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Appelbaum KL, Bazemore PH, Tonkonogy J, Ananth R, Shull S. Privilege and discharge decisions for psychiatric inpatients with dysphagia. Hosp Community Psychiatry 1992; 43:1023-5. [PMID: 1398566 DOI: 10.1176/ps.43.10.1023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Psychiatric patients have an increased risk for choking compared with the general population because of risk factors such as medication side effects and food gorging. A state hospital program for managing patients with dysphagia, or difficulty swallowing, includes interventions such as modified diets, mealtime monitoring, and adjusting psychotropic medications. Clinicians may find it difficult to make decisions about privileges and placement for dysphagic patients who do not comply with dietary modifications in unsupervised settings. For many such patients, close supervision and even placement on a locked ward may seem necessary. The authors recommend a risk-benefit approach: clinicians must balance the safety afforded by restrictions against the benefits of increased privileges or placement in a less restrictive setting. Quality of life and patients' preferences must also be considered.
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Affiliation(s)
- K L Appelbaum
- University of Massachusetts Medical School, Worcester 01655
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Abstract
Deaths due to airway obstruction are more common in psychiatric inpatients than in the normal population. A dysphagia program was started in a 400 bed Massachusetts psychiatric hospital after 4 patients in 1 year died from asphyxia. In the year after the program was started, there were no deaths; however, 28 patients experienced 32 choking incidents. The 28 patients received clinical evaluations by speech pathologists, neurologists, psychiatrists, and internists. Of the incidents, 55% required use of the Heimlich maneuver to open the airway. Choking incidents could be classified into five types based on results of clinical examination: bradykinetic, dyskinetic, fast eating syndrome, paralytic, and medical. Twenty-one of the 28 patients were studied by videofluoroscopy and 86% of the videos were abnormal, showing aspiration in eight, webs in five, and delay in the oral phase in five. Patients with bradykinetic dysphagia (secondary to neuroleptic-induced extra-pyramidal syndrome [EPS]) and paralytic dysphagia appeared to experience a more severe form of choking.
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Affiliation(s)
- P H Bazemore
- University of Massachusetts Medical Center, Worcester
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