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24 results on '"Pham, Tuan M."'

1. Optical frequency analysis on dark state of a single trapped ion

Author

Lešundák, Adam, Pham, Tuan M., Čížek, Martin, Obšil, Petr, Slodička, Lukáš, and Číp, Ondřej

Subjects
Physics - Optics, Quantum Physics
Abstract

We demonstrate an optical frequency analysis method using the Fourier transform of detection times of fluorescence photons emitted from a single trapped 40Ca+ ion. The response of the detected photon rate to the relative laser frequency deviations is recorded within the slope of a dark resonance formed in the lambda-type energy level scheme corresponding to two optical dipole transitions. This approach enhances the sensitivity to the small frequency deviations and does so with reciprocal dependence on the fluorescence rate. The employed lasers are phase locked to an optical frequency comb, which allows for precise calibration of optical frequency analysis by deterministic modulation of the analyzed laser beam with respect to the reference beam. The attainable high signal-to-noise ratios of up to a MHz range of modulation deviations and up to a hundred kHz modulation frequencies promise the applicability of the presented results in a broad range of optical spectroscopic applications.

Published
2020
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2. Laser source for dimensional metrology: investigation of an iodine stabilized system based on narrow linewidth 633 nm DBR diode

Author

Rerucha, Simon, Yacoot, Andrew, Pham, Tuan M, Cizek, Martin, Hucl, Vaclav, Lazar, Josef, and Cip, Ondrej

Subjects
Physics - Optics, Physics - Instrumentation and Detectors
Abstract

We demonstrated that an iodine stabilized Distributed Bragg Reflector (DBR) diode based laser system lasing at a wavelength in close proximity to $\lambda = 633\,$nm could be used as an alternative laser source to the He-Ne lasers in both scientific and industrial metrology. This yields additional advantages besides the optical frequency stability and coherence: inherent traceability, wider optical frequency tuning range, higher output power and high frequency modulation capability. We experimentally investigated the characteristics of the laser source in two major steps: first using a wavelength meter referenced to a frequency comb controlled with a hydrogen maser and then on a interferometric optical bench testbed where we compared the performance of the laser system with that of a traditional frequency stabilized He-Ne laser. The results indicate that DBR diode laser system provides a good laser source for applications in dimensional (nano)metrology, especially in conjunction with novel interferometric detection methods exploiting high frequency modulation or multiaxis measurement systems., Comment: Published 16 February 2017 copyright 2017 IOP Publishing Ltd

Published
2019
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5. DNA Structure Design Is Improved Using an Artificially Expanded Alphabet of Base Pairs Including Loop and Mismatch Thermodynamic Parameters

Author

Pham, Tuan M., primary, Miffin, Terrel, additional, Sun, Hongying, additional, Sharp, Kenneth K., additional, Wang, Xiaoyu, additional, Zhu, Mingyi, additional, Hoshika, Shuichi, additional, Peterson, Raymond J., additional, Benner, Steven A., additional, Kahn, Jason D., additional, and Mathews, David H., additional

Published
2023
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9. Parameters of anger as related to sensory-affective components of pain.

Author

Fernandez, Ephrem, Pham, Tuan M., Kolaparthi, Krishna, Sun, Renhao, Perez, Brandon S., Iwuala, Emmanuel C., Wu, Wenbo, and Shattuck, Eric C.

Abstract

Comorbid with chronic pain are negative emotions, anger being particularly salient. To evaluate specific relationships between pain and anger, the present study deconstructed anger into five parameters and dichotomized pain into sensory vs. affective components. Hypotheses were (i) anger parameters would be significantly and positively correlated with affective pain more so than with sensory pain, and (ii) individual parameters would be differentially related to pain components. The Anger Parameters Scale (APS) was used to rate five parameters of anger: frequency, duration, intensity, latency, and threshold. Also rated was the physical sensation of pain and the degree of distress from pain. The volunteer sample comprised n=51 chronic pain patients, varying in ethnicity/race and educational level. Descriptive statistics revealed: APS total M=71.52, SD=16.68, Sensory pain M=6.27, SD=2.15, Affective pain M=5.76, SD=2.28. Sensory and affective pain were highly correlated, r=0.70. APS total was significantly associated with affective pain (r=+0.28) but hardly with sensory pain (r=0.12). Two anger parameters significantly correlated with affective pain: anger frequency (r=+0.30, p<0.05) and anger threshold (r=+0.33, p<0.05). Secondarily, certain educational levels (but not gender and ethnicity/race) were associated with significantly higher APS total scores. Scores for all variables were in the mid-range. As hypothesized, anger was more strongly correlated with distress/suffering of pain than with physical sensation of pain, though both pain components were closely coupled. Specific findings regarding frequency and threshold imply that being angry often and being oversensitive to provocation are associated with greater distress in this context. In deconstructing anger and dichotomizing pain, the present study extends previous research by elaborating on what aspects of anger are most related to which components of pain. Moreover, certain educational levels with higher levels of anger may need special attention. Further research could examine if treatment of anger might lead to corresponding changes in chronic pain. [ABSTRACT FROM AUTHOR]

Published
2023
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10. Sharing Best Practice: Establishing a National Vietnamese Pediatric Hematopoietic Stem Cell Transplant and Cellular Therapy Consortium

Author

Nguyen, Sang M., primary, Huynh, Phu D.V., additional, Abramovitz, Linda, additional, Agrawal, Anu, additional, Assanasen, Chatchawin, additional, Blair, Sally, additional, Chu, Minh H., additional, Faulkner, Lawrence, additional, Hoang, Tram T.A., additional, Ho, Hang T.K., additional, Horn, Biljana, additional, Huynh, Chau T.B., additional, Le, Anh H., additional, Le, Phuong B., additional, Le, Son T., additional, Noonan, Nancy, additional, Nguyen, Dinh V., additional, Nguyen, Hang T.T., additional, Nguyen, Hoa T.K., additional, Nguyen, Nam H., additional, Nguyen, Nhai T., additional, Nguyen, Tho T., additional, Oh, Jess, additional, Palma, Julia, additional, Phan, Trang T.T., additional, Pham, Anh T.N., additional, Pham, Tuan M., additional, Rees, Hannah, additional, Tan, Poh-Lin, additional, Tran, My, additional, Vo, Binh T.T., additional, Watanabe, Kazuyo, additional, Yi, Hyeon Gyu, additional, Bui, Lan N., additional, and Hermiston, Michelle, additional

Published
2022
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12. Sensing fields with ion in a dark state

Author

Lešundák, Adam, primary, Pham, Tuan M., additional, Čížek, Martin, additional, Grim, Jakub, additional, Jedlička, Petr, additional, Podhora, Lukáš, additional, Slodička, Lukáš, additional, and Číp, Ondřej, additional

Published
2021
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14. Optical frequency analysis on dark state of a single trapped ion

Author

Le��und��k, Adam, Pham, Tuan M., ������ek, Martin, Ob��il, Petr, Slodi��ka, Luk����, and ����p, Ond��ej

Subjects
Physics::Optics, FOS: Physical sciences, Quantum Physics (quant-ph), Optics (physics.optics)
Abstract

We demonstrate an optical frequency analysis method using the Fourier transform of detection times of fluorescence photons emitted from a single trapped 40Ca+ ion. The response of the detected photon rate to the relative laser frequency deviations is recorded within the slope of a dark resonance formed in the lambda-type energy level scheme corresponding to two optical dipole transitions. This approach enhances the sensitivity to the small frequency deviations and does so with reciprocal dependence on the fluorescence rate. The employed lasers are phase locked to an optical frequency comb, which allows for precise calibration of optical frequency analysis by deterministic modulation of the analyzed laser beam with respect to the reference beam. The attainable high signal-to-noise ratios of up to a MHz range of modulation deviations and up to a hundred kHz modulation frequencies promise the applicability of the presented results in a broad range of optical spectroscopic applications.

Published
2020
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17. 444 - Sharing Best Practice: Establishing a National Vietnamese Pediatric Hematopoietic Stem Cell Transplant and Cellular Therapy Consortium

Author

Nguyen, Sang M., Huynh, Phu D.V., Abramovitz, Linda, Agrawal, Anu, Assanasen, Chatchawin, Blair, Sally, Chu, Minh H., Faulkner, Lawrence, Hoang, Tram T.A., Ho, Hang T.K., Horn, Biljana, Huynh, Chau T.B., Le, Anh H., Le, Phuong B., Le, Son T., Noonan, Nancy, Nguyen, Dinh V., Nguyen, Hang T.T., Nguyen, Hoa T.K., Nguyen, Nam H., Nguyen, Nhai T., Nguyen, Tho T., Oh, Jess, Palma, Julia, Phan, Trang T.T., Pham, Anh T.N., Pham, Tuan M., Rees, Hannah, Tan, Poh-Lin, Tran, My, Vo, Binh T.T., Watanabe, Kazuyo, Yi, Hyeon Gyu, Bui, Lan N., and Hermiston, Michelle

Published
2022
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24. DNA Structure Design Is Improved Using an Artificially Expanded Alphabet of Base Pairs Including Loop and Mismatch Thermodynamic Parameters.

Author

Pham TM, Miffin T, Sun H, Sharp KK, Wang X, Zhu M, Hoshika S, Peterson RJ, Benner SA, Kahn JD, and Mathews DH

Abstract

We show that in silico design of DNA secondary structures is improved by extending the base pairing alphabet beyond A-T and G-C to include the pair between 2-amino-8-(1'-β-D-2'-deoxyribofuranosyl)-imidazo-[1,2- a ]-1,3,5-triazin-(8 H )-4-one and 6-amino-3-(1'-β-D-2'-deoxyribofuranosyl)-5-nitro-(1 H )-pyridin-2-one, simply P and Z. To obtain the thermodynamic parameters needed to include P-Z pairs in the designs, we performed 47 optical melting experiments and combined the results with previous work to fit a new set of free energy and enthalpy nearest neighbor folding parameters for P-Z pairs and G-Z wobble pairs. We find that G-Z pairs have stability comparable to A-T pairs and therefore should be considered quantitatively by structure prediction and design algorithms. Additionally, we extrapolated the set of loop, terminal mismatch, and dangling end parameters to include P and Z nucleotides. These parameters were incorporated into the RNAstructure software package for secondary structure prediction and analysis. Using the RNAstructure Design program, we solved 99 of the 100 design problems posed by Eterna using the ACGT alphabet or supplementing with P-Z pairs. Extending the alphabet reduced the propensity of sequences to fold into off-target structures, as evaluated by the normalized ensemble defect (NED). The NED values were improved relative to those from the Eterna example solutions in 91 of 99 cases where Eterna-player solutions were provided. P-Z-containing designs had average NED values of 0.040, significantly below the 0.074 of standard-DNA-only designs, and inclusion of the P-Z pairs decreased the time needed to converge on a design. This work provides a sample pipeline for inclusion of any expanded alphabet nucleotides into prediction and design workflows.

Published
2023
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