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Cecconi V, Kumar V, Pasquazi A, Totero Gongora JS, Peccianti M. Nonlinear field-control of terahertz waves in random media for spatiotemporal focusing. OPEN RESEARCH EUROPE 2023; 2:32. [PMID: 37645307 PMCID: PMC10445851 DOI: 10.12688/openreseurope.14508.2] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 01/30/2023] [Indexed: 09/15/2023]
Abstract
Controlling the transmission of broadband optical pulses in scattering media is a critical open challenge in photonics. To date, wavefront shaping techniques at optical frequencies have been successfully applied to control the spatial properties of multiple-scattered light. However, a fundamental restriction in achieving an equivalent degree of control over the temporal properties of a broadband pulse is the limited availability of experimental techniques to detect the coherent properties (i.e., the spectral amplitude and absolute phase) of the transmitted field. Terahertz experimental frameworks, on the contrary, enable measuring the field dynamics of broadband pulses at ultrafast (sub-cycle) time scales directly. In this work, we provide a theoretical/numerical demonstration that, within this context, complex scattering can be used to achieve spatio-temporal control of instantaneous fields and manipulate the temporal properties of single-cycle pulses by solely acting on spatial degrees of freedom of the illuminating field. As direct application scenarios, we demonstrate spatio-temporal focusing, chirp compensation, and control of the carrier-envelope-phase (CEP) of a CP-stable, transform-limited THz pulse.
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Affiliation(s)
- Vittorio Cecconi
- Emergent Photonics (EPic) Lab, Department of Physics and Astronomy, University of Sussex, Brighton, BN19QH, UK
- Emergent Photonics Research Centre and Dept. of Physics, Loughborough University, Loughborough, LE11 3TU, UK
| | - Vivek Kumar
- Emergent Photonics (EPic) Lab, Department of Physics and Astronomy, University of Sussex, Brighton, BN19QH, UK
| | - Alessia Pasquazi
- Emergent Photonics (EPic) Lab, Department of Physics and Astronomy, University of Sussex, Brighton, BN19QH, UK
- Emergent Photonics Research Centre and Dept. of Physics, Loughborough University, Loughborough, LE11 3TU, UK
| | - Juan Sebastian Totero Gongora
- Emergent Photonics (EPic) Lab, Department of Physics and Astronomy, University of Sussex, Brighton, BN19QH, UK
- Emergent Photonics Research Centre and Dept. of Physics, Loughborough University, Loughborough, LE11 3TU, UK
| | - Marco Peccianti
- Emergent Photonics (EPic) Lab, Department of Physics and Astronomy, University of Sussex, Brighton, BN19QH, UK
- Emergent Photonics Research Centre and Dept. of Physics, Loughborough University, Loughborough, LE11 3TU, UK
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Cecconi V, Kumar V, Pasquazi A, Totero Gongora JS, Peccianti M. Nonlinear field-control of terahertz waves in random media for spatiotemporal focusing. OPEN RESEARCH EUROPE 2023; 2:32. [PMID: 37645307 PMCID: PMC10445851 DOI: 10.12688/openreseurope.14508.3] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 01/30/2023] [Indexed: 08/31/2023]
Abstract
Controlling the transmission of broadband optical pulses in scattering media is a critical open challenge in photonics. To date, wavefront shaping techniques at optical frequencies have been successfully applied to control the spatial properties of multiple-scattered light. However, a fundamental restriction in achieving an equivalent degree of control over the temporal properties of a broadband pulse is the limited availability of experimental techniques to detect the coherent properties (i.e., the spectral amplitude and absolute phase) of the transmitted field. Terahertz experimental frameworks, on the contrary, enable measuring the field dynamics of broadband pulses at ultrafast (sub-cycle) time scales directly. In this work, we provide a theoretical/numerical demonstration that, within this context, complex scattering can be used to achieve spatio-temporal control of instantaneous fields and manipulate the temporal properties of single-cycle pulses by solely acting on spatial degrees of freedom of the illuminating field. As direct application scenarios, we demonstrate spatio-temporal focusing, chirp compensation, and control of the carrier-envelope-phase (CEP) of a CP-stable, transform-limited THz pulse.
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Affiliation(s)
- Vittorio Cecconi
- Emergent Photonics (EPic) Lab, Department of Physics and Astronomy, University of Sussex, Brighton, BN19QH, UK
- Emergent Photonics Research Centre and Dept. of Physics, Loughborough University, Loughborough, LE11 3TU, UK
| | - Vivek Kumar
- Emergent Photonics (EPic) Lab, Department of Physics and Astronomy, University of Sussex, Brighton, BN19QH, UK
| | - Alessia Pasquazi
- Emergent Photonics (EPic) Lab, Department of Physics and Astronomy, University of Sussex, Brighton, BN19QH, UK
- Emergent Photonics Research Centre and Dept. of Physics, Loughborough University, Loughborough, LE11 3TU, UK
| | - Juan Sebastian Totero Gongora
- Emergent Photonics (EPic) Lab, Department of Physics and Astronomy, University of Sussex, Brighton, BN19QH, UK
- Emergent Photonics Research Centre and Dept. of Physics, Loughborough University, Loughborough, LE11 3TU, UK
| | - Marco Peccianti
- Emergent Photonics (EPic) Lab, Department of Physics and Astronomy, University of Sussex, Brighton, BN19QH, UK
- Emergent Photonics Research Centre and Dept. of Physics, Loughborough University, Loughborough, LE11 3TU, UK
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Cecconi V, Kumar V, Pasquazi A, Totero Gongora JS, Peccianti M. Nonlinear field-control of terahertz waves in random media for spatiotemporal focusing. OPEN RESEARCH EUROPE 2023; 2:32. [PMID: 37645307 PMCID: PMC10445851 DOI: 10.12688/openreseurope.14508.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 01/30/2023] [Indexed: 09/26/2024]
Abstract
Controlling the transmission of broadband optical pulses in scattering media is a critical open challenge in photonics. To date, wavefront shaping techniques at optical frequencies have been successfully applied to control the spatial properties of multiple-scattered light. However, a fundamental restriction in achieving an equivalent degree of control over the temporal properties of a broadband pulse is the limited availability of experimental techniques to detect the coherent properties (i.e., the spectral amplitude and absolute phase) of the transmitted field. Terahertz experimental frameworks, on the contrary, enable measuring the field dynamics of broadband pulses at ultrafast (sub-cycle) time scales directly. In this work, we provide a theoretical/numerical demonstration that, within this context, complex scattering can be used to achieve spatio-temporal control of instantaneous fields and manipulate the temporal properties of single-cycle pulses by solely acting on spatial degrees of freedom of the illuminating field. As direct application scenarios, we demonstrate spatio-temporal focusing, chirp compensation, and control of the carrier-envelope-phase (CEP) of a CP-stable, transform-limited THz pulse.
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Affiliation(s)
- Vittorio Cecconi
- Emergent Photonics (EPic) Lab, Department of Physics and Astronomy, University of Sussex, Brighton, BN19QH, UK
- Emergent Photonics Research Centre and Dept. of Physics, Loughborough University, Loughborough, LE11 3TU, UK
| | - Vivek Kumar
- Emergent Photonics (EPic) Lab, Department of Physics and Astronomy, University of Sussex, Brighton, BN19QH, UK
| | - Alessia Pasquazi
- Emergent Photonics (EPic) Lab, Department of Physics and Astronomy, University of Sussex, Brighton, BN19QH, UK
- Emergent Photonics Research Centre and Dept. of Physics, Loughborough University, Loughborough, LE11 3TU, UK
| | - Juan Sebastian Totero Gongora
- Emergent Photonics (EPic) Lab, Department of Physics and Astronomy, University of Sussex, Brighton, BN19QH, UK
- Emergent Photonics Research Centre and Dept. of Physics, Loughborough University, Loughborough, LE11 3TU, UK
| | - Marco Peccianti
- Emergent Photonics (EPic) Lab, Department of Physics and Astronomy, University of Sussex, Brighton, BN19QH, UK
- Emergent Photonics Research Centre and Dept. of Physics, Loughborough University, Loughborough, LE11 3TU, UK
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Yanina IY, Nikolaev VV, Zakharova OA, Borisov AV, Dvoretskiy KN, Berezin KV, Kochubey VI, Kistenev YV, Tuchin VV. Measurement and Modeling of the Optical Properties of Adipose Tissue in the Terahertz Range: Aspects of Disease Diagnosis. Diagnostics (Basel) 2022; 12:2395. [PMID: 36292084 PMCID: PMC9600075 DOI: 10.3390/diagnostics12102395] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 09/19/2022] [Accepted: 09/26/2022] [Indexed: 11/16/2022] Open
Abstract
In this paper, the measurement and modeling of optical properties in the terahertz (THz) range of adipose tissue and its components with temperature changes were performed. Spectral measurements were made in the frequency range 0.25-1 THz. The structural models of main triglycerides of fatty acids are constructed using the B3LYP/6-31G(d) method and the Gaussian03, Revision B.03 program. The optical density (OD) of adipose tissue samples decreases as temperature increases, which can be associated mostly with the dehydration of the sample. Some inclusion of THz wave scattering suppression into the OD decrease can also be expected due to refractive index matching provided by free fatty acids released from adipocytes at thermally induced cell lipolysis. It was shown that the difference between the THz absorption spectra of water and fat makes it possible to estimate the water content in adipose tissue. The proposed model was verified on the basis of molecular modeling and a comparison with experimental data for terahertz spectra of adipose tissue during its heating. Knowing the exact percentage of free and bound water in adipose tissue can help diagnose and monitor diseases, such as diabetes, obesity, and cancer.
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Affiliation(s)
- Irina Y. Yanina
- Institute of Physics, Saratov State University, 410012 Saratov, Russia
- Laboratory of Laser Molecular Imaging and Machine Learning, Tomsk State University, 634050 Tomsk, Russia
| | - Viktor V. Nikolaev
- Laboratory of Laser Molecular Imaging and Machine Learning, Tomsk State University, 634050 Tomsk, Russia
| | - Olga A. Zakharova
- Laboratory of Laser Molecular Imaging and Machine Learning, Tomsk State University, 634050 Tomsk, Russia
| | - Alexei V. Borisov
- Laboratory of Laser Molecular Imaging and Machine Learning, Tomsk State University, 634050 Tomsk, Russia
| | | | - Kirill V. Berezin
- Institute of Physics, Saratov State University, 410012 Saratov, Russia
| | - Vyacheslav I. Kochubey
- Institute of Physics, Saratov State University, 410012 Saratov, Russia
- Laboratory of Laser Molecular Imaging and Machine Learning, Tomsk State University, 634050 Tomsk, Russia
| | - Yuri V. Kistenev
- Laboratory of Laser Molecular Imaging and Machine Learning, Tomsk State University, 634050 Tomsk, Russia
| | - Valery V. Tuchin
- Institute of Physics, Saratov State University, 410012 Saratov, Russia
- Laboratory of Laser Molecular Imaging and Machine Learning, Tomsk State University, 634050 Tomsk, Russia
- Institute of Precision Mechanics and Control, FRC “Saratov Scientific Centre of the Russian Academy of Sciences”, 410028 Saratov, Russia
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Tarabichi S, Al-Raeei M, Solieva O. Improving the accuracy of tumor surgery by THz imaging and making the results of pathological anatomy faster by THz spectroscopy. BENI-SUEF UNIVERSITY JOURNAL OF BASIC AND APPLIED SCIENCES 2022. [DOI: 10.1186/s43088-022-00201-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
The terahertz radiation is a specific part of the electromagnetic radiation spectrum and has multiple significant applications in multiple scientific researches such as the applications in the medicine. An important application of the terahertz is its use in tumor imaging which is very important in the tumor surgery; however, lots of physicians and workers in the medical field have little information or having no information at all, dealing with this significant part of the electromagnetic spectrum.
Results
In this work, we interviewed a number of local surgeons in Syrian Arab Republic, who reported that they visually delineate the contour of tumors to be removed, and in order to reduce the number of future possible interventions, a large margin of healthy tissue is often excised. Furthermore, a number of pathologists who reported that preparing samples of excised tissues for examination takes a long period of time which may extend to several days, and that the results of histopathology indicate in some cases the integrity of removed tissues.
Conclusion
We have found that a significant number of participants in the survey demonstrated that the importance of dealing with terahertz imaging and terahertz spectroscopy, encouraging to implement the technique in the Syrian Arab Republic.
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Zhang T, Nazarov R, Popov AP, Demchenko PS, Bykov AV, Grigorev RO, Kuzikova AV, Soboleva VY, Zykov DV, Meglinski IV, Khodzitskiy MK. Development of oral cancer tissue-mimicking phantom based on polyvinyl chloride plastisol and graphite for terahertz frequencies. JOURNAL OF BIOMEDICAL OPTICS 2020; 25:JBO-200288SSR. [PMID: 33205633 PMCID: PMC7670095 DOI: 10.1117/1.jbo.25.12.123002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Accepted: 10/26/2020] [Indexed: 06/11/2023]
Abstract
SIGNIFICANCE A new concept of a biotissue phantom for terahertz (THz) biomedical applications is needed for reliable and long-term usage. AIM We aimed to develop a new type of biotissue phantom without water content and with controllable THz optical properties by applying graphite powders into a polyvinyl chloride plastisol (PVCP) matrix and to give a numerical description to the THz optical properties of the phantoms using the Bruggeman model (BM) of the effective medium theory (EMT). APPROACH The THz optical properties of graphite and the PVCP matrix were measured using THz time-domain spectroscopy, which works in the frequency range from 0.1 to 1 THz. Two phantoms with 10% and 12.5% graphite were fabricated to evaluate the feasibility of describing phantoms using the EMT. The EMT then was used to determine the concentration of graphite required to mimic the THz optical properties of human cancerous and healthy oral tissue. RESULTS The phantom with 16.7% of graphite has the similar THz optical properties as human cancerous oral tissue in the frequency range of 0.2 to 0.7 THz. The THz optical properties of the phantom with 21.9% of graphite are close to those of human healthy oral tissue in the bandwidth from 0.6 to 0.8 THz. Both the refractive index and absorption coefficient of the samples increase with an increase of graphite concentration. The BM of the EMT was used as the numerical model to describe the THz optical properties of the phantoms. The relative error of the BM for the refractive index estimation and the absorption coefficient is up to 4% and 8%, respectively. CONCLUSIONS A water-free biotissue phantom that mimics the THz optical properties of human cancerous oral tissue was developed. With 21.9% of graphite, the phantom also mimics human healthy oral tissue in a narrow frequency range. The BM proved to be a suitable numerical model of the phantom.
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Affiliation(s)
- Tianmiao Zhang
- ITMO University, School of Photonics, Terahertz Biomedicine Laboratory, Saint Petersburg, Russia
- Tydex LLC, Saint Petersburg, Russia
| | - Ravshanjon Nazarov
- ITMO University, School of Photonics, Terahertz Biomedicine Laboratory, Saint Petersburg, Russia
| | - Alexey P. Popov
- University of Oulu, Faculty of Information Technology and Electrical Engineering, Optoelectronics and Measurement Techniques Laboratory, Oulu, Finland
| | - Petr S. Demchenko
- ITMO University, School of Photonics, Terahertz Biomedicine Laboratory, Saint Petersburg, Russia
| | - Alexander V. Bykov
- University of Oulu, Faculty of Information Technology and Electrical Engineering, Optoelectronics and Measurement Techniques Laboratory, Oulu, Finland
| | - Roman O. Grigorev
- ITMO University, School of Photonics, Terahertz Biomedicine Laboratory, Saint Petersburg, Russia
| | - Anna V. Kuzikova
- ITMO University, School of Photonics, Terahertz Biomedicine Laboratory, Saint Petersburg, Russia
| | - Victoria Y. Soboleva
- ITMO University, School of Photonics, Terahertz Biomedicine Laboratory, Saint Petersburg, Russia
| | - Dmitry V. Zykov
- ITMO University, School of Photonics, Terahertz Biomedicine Laboratory, Saint Petersburg, Russia
| | - Igor V. Meglinski
- University of Oulu, Faculty of Information Technology and Electrical Engineering, Optoelectronics and Measurement Techniques Laboratory, Oulu, Finland
- Aston University, Aston Institute of Materials Research, School of Engineering and Applied Science, Birmingham, United Kingdom
- Aston University, School of Life and Health Sciences, Birmingham, United Kingdom
| | - Mikhail K. Khodzitskiy
- ITMO University, School of Photonics, Terahertz Biomedicine Laboratory, Saint Petersburg, Russia
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Betzalel N, Ben Ishai P, Feldman Y. The human skin as a sub-THz receiver - Does 5G pose a danger to it or not? ENVIRONMENTAL RESEARCH 2018; 163:208-216. [PMID: 29459303 DOI: 10.1016/j.envres.2018.01.032] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2017] [Revised: 12/18/2017] [Accepted: 01/23/2018] [Indexed: 06/08/2023]
Abstract
In the interaction of microwave radiation and human beings, the skin is traditionally considered as just an absorbing sponge stratum filled with water. In previous works, we showed that this view is flawed when we demonstrated that the coiled portion of the sweat duct in upper skin layer is regarded as a helical antenna in the sub-THz band. Experimentally we showed that the reflectance of the human skin in the sub-THz region depends on the intensity of perspiration, i.e. sweat duct's conductivity, and correlates with levels of human stress (physical, mental and emotional). Later on, we detected circular dichroism in the reflectance from the skin, a signature of the axial mode of a helical antenna. The full ramifications of what these findings represent in the human condition are still unclear. We also revealed correlation of electrocardiography (ECG) parameters to the sub-THz reflection coefficient of human skin. In a recent work, we developed a unique simulation tool of human skin, taking into account the skin multi-layer structure together with the helical segment of the sweat duct embedded in it. The presence of the sweat duct led to a high specific absorption rate (SAR) of the skin in extremely high frequency band. In this paper, we summarize the physical evidence for this phenomenon and consider its implication for the future exploitation of the electromagnetic spectrum by wireless communication. Starting from July 2016 the US Federal Communications Commission (FCC) has adopted new rules for wireless broadband operations above 24 GHz (5 G). This trend of exploitation is predicted to expand to higher frequencies in the sub-THz region. One must consider the implications of human immersion in the electromagnetic noise, caused by devices working at the very same frequencies as those, to which the sweat duct (as a helical antenna) is most attuned. We are raising a warning flag against the unrestricted use of sub-THz technologies for communication, before the possible consequences for public health are explored.
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Affiliation(s)
- Noa Betzalel
- Department of Applied Physics, The Rachel and Selim Benin School of Engineering and Computer Science, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem 91904, Israel
| | - Paul Ben Ishai
- Department of Applied Physics, The Rachel and Selim Benin School of Engineering and Computer Science, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem 91904, Israel; Department of Physics, Ariel University, Ariel 40700, Israel
| | - Yuri Feldman
- Department of Applied Physics, The Rachel and Selim Benin School of Engineering and Computer Science, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem 91904, Israel.
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Bowman T, Walter A, Shenderova O, Nunn N, McGuire G, El-Shenawee M. A Phantom Study of Terahertz Spectroscopy and Imaging of Micro- and Nano-diamonds and Nano-onions as Contrast Agents for Breast Cancer. Biomed Phys Eng Express 2017; 3:055001. [PMID: 29527326 PMCID: PMC5839518 DOI: 10.1088/2057-1976/aa87c2] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
THz imaging is effective in distinguishing between cancerous, healthy, and fatty tissues in breast tumors, but a challenge remains in the contrast between cancerous and fibroglandular (healthy) tissues. This work investigates carbon-based nanoparticles as potential contrast agents for terahertz imaging of breast cancer. Microdiamonds, nanodiamonds, and nanometer-scale onion-like carbon are characterized with terahertz transmission spectroscopy in low-absorption backgrounds of polydimethylsiloxane or polyethylene. The refractive index and absorption coefficients are calculated based on the measured electric fields. Nanodiamonds show little effect on the terahertz signal, microdiamonds express resonance-like, size-dependent absorption peaks, and onion-like carbon provides a uniform increase in the optical properties even at low concentration. Due to its strong interaction with terahertz frequencies and ability to be activated for selective binding to cancer cells, onion-like carbon is implemented into engineered three-dimensional breast tumor models composed of phantom tissue mimicking infiltrating ductal carcinoma surrounded by a phantom mimicking healthy fibroglandular tissue. This model is imaged using the terahertz reflection mode to examine the effectiveness of contrast agents for differentiation between the two tissue types. In both spectroscopy and imaging, a 10% concentration of onion-like carbon shows the strongest impact on the terahertz signal and holds promise as a terahertz contrast agent.
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Affiliation(s)
- Tyler Bowman
- University of Arkansas, Department of Electrical Engineering, 3217 Bell Engineering Center, Fayetteville, AR, USA 72701
| | - Alec Walter
- University of Arkansas, Department of Electrical Engineering, 3217 Bell Engineering Center, Fayetteville, AR, USA 72701
| | - Olga Shenderova
- Adámas Nanotechnologies, Inc., 8100 Brownleigh Dr Suite 120, Raleigh, NC 27617
| | - Nicholas Nunn
- Adámas Nanotechnologies, Inc., 8100 Brownleigh Dr Suite 120, Raleigh, NC 27617
| | - Gary McGuire
- Adámas Nanotechnologies, Inc., 8100 Brownleigh Dr Suite 120, Raleigh, NC 27617
| | - Magda El-Shenawee
- University of Arkansas, Department of Electrical Engineering, 3217 Bell Engineering Center, Fayetteville, AR, USA 72701
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Tang M, Huang Q, Wei D, Zhao G, Chang T, Kou K, Wang M, Du C, Fu WL, Cui HL. Terahertz spectroscopy of oligonucleotides in aqueous solutions. JOURNAL OF BIOMEDICAL OPTICS 2015; 20:095009. [PMID: 26385423 DOI: 10.1117/1.jbo.20.9.095009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 08/17/2015] [Indexed: 06/05/2023]
Abstract
A terahertz (THz) spectroscopic study is carried out to analyze DNA mutations in a label-free manner. Three newly designed liquid sample cells are considered and the best is selected as the sample carrier for THz transmission spectroscopic analyses. Discrimination based on spectral signatures of single-base mutations on single-stranded 20 nt oligonucleotides has been shown possible experimentally. The results clearly attest the ability of this promising approach for label-free analyses of single-base mutations of DNA molecules. This study has demonstrated that the THz spectroscopic technology can be considered as a potential diagnostic tool for investigating molecular reactions, such as DNA mutations.
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Affiliation(s)
- Mingjie Tang
- Chinese Academy of Sciences, Chongqing Institute of Green and Intelligent Technology, Chongqing Key Laboratory of Multi-Scale Manufacturing Technology, No. 266 Fangzheng Avenue, Shuitu Hi-tech Industrial Park, Shuitu Town, Beibei District, Chongqing 40071
| | - Qing Huang
- Third Military Medical University, Southwest Hospital, Department of Laboratory Medicine, Chongqing 400038, China
| | - Dongshan Wei
- Chinese Academy of Sciences, Chongqing Institute of Green and Intelligent Technology, Chongqing Key Laboratory of Multi-Scale Manufacturing Technology, No. 266 Fangzheng Avenue, Shuitu Hi-tech Industrial Park, Shuitu Town, Beibei District, Chongqing 40071
| | - Guozhong Zhao
- Capital Normal University, Department of Physics, Beijing 100048, China
| | - Tianying Chang
- Chinese Academy of Sciences, Chongqing Institute of Green and Intelligent Technology, Chongqing Key Laboratory of Multi-Scale Manufacturing Technology, No. 266 Fangzheng Avenue, Shuitu Hi-tech Industrial Park, Shuitu Town, Beibei District, Chongqing 40071
| | - Kuan Kou
- Capital Normal University, Department of Physics, Beijing 100048, China
| | - Min Wang
- Jilin University, College of Instrumentation Science and Electrical Engineering, Changchun, Jilin 130061, China
| | - Chunlei Du
- Chinese Academy of Sciences, Chongqing Institute of Green and Intelligent Technology, Chongqing Key Laboratory of Multi-Scale Manufacturing Technology, No. 266 Fangzheng Avenue, Shuitu Hi-tech Industrial Park, Shuitu Town, Beibei District, Chongqing 40071
| | - Wei-ling Fu
- Third Military Medical University, Southwest Hospital, Department of Laboratory Medicine, Chongqing 400038, China
| | - Hong-Liang Cui
- Chinese Academy of Sciences, Chongqing Institute of Green and Intelligent Technology, Chongqing Key Laboratory of Multi-Scale Manufacturing Technology, No. 266 Fangzheng Avenue, Shuitu Hi-tech Industrial Park, Shuitu Town, Beibei District, Chongqing 40071
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Pogson EM, McNamara J, Metcalfe P, Lewis RA. Comparing and evaluating the efficacy of the TOR18FG Leeds test X-ray phantom for T-rays. Quant Imaging Med Surg 2013; 3:18-27. [PMID: 23483115 PMCID: PMC3591503 DOI: 10.3978/j.issn.2223-4292.2013.02.05] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2013] [Accepted: 02/27/2013] [Indexed: 11/14/2022]
Abstract
The commercially available X-ray fluoroscopy quality assurance phantom, the Leeds test object TOR18FG, was found to be suitable to assess T-ray image quality in the range (0.1-0.4) THz at a depth of 0.5 cm. Previous to this only custom made phantoms, made especially for the T-ray region, assessed T-ray spatial resolution. However, if sub-wavelength techniques are used, the Leeds test phantom may be implemented to measure the T-ray systems spatial resolution, allowing us to directly compare X-ray and T-ray spatial resolution. The systems compared include a Gulmay Orthovoltage machine (X-ray), the On Board Imager (OBI) of a Varian linear accelerator (X-ray), a two-colour system (T-ray) and Terahertz Time Domain Spectroscopy (THz-TDS) system. X-rays were found to have a spatial resolution of 1.25 lp/mm using the On Board Imager of a Varian Linear Accelerator whilst T-rays imaged using a broadband source imaged through a spatial pinhole had a spatial resolution of 0.56 lp/mm. The TOR18FG background material was found to block, 90% and 99% of the broadband T-rays emitted from a THz-TDS photo-conductive emitter, at 0.4 THz and 0.53 THz respectively. Contrast sensitivity was found to be 3% for 25 cm × 25 cm X-ray field at 65 kV, whilst this value could not be established for T-rays using the TOR18FG. All contrast circles were found to be the same for T-rays i.e. all 40% at 0.1 THz. Images of the same leaf were taken with diagnostic X-rays and both broadband and continuous wave (CW) T-ray systems. T-rays proved superior in providing image contrast, for a hydrated leaf, over X-rays.
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Affiliation(s)
- Elise Maree Pogson
- Institute for Superconducting and Electronic Materials, University of Wollongong, Wollongong, NSW 2522, Australia
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Joanne McNamara
- Department of Medical Physics, Illawarra Cancer Care Centre, Locked Bag 8808, South Coast Mail Centre, Wollongong, NSW 2521, Australia
| | - Peter Metcalfe
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Roger A Lewis
- Institute for Superconducting and Electronic Materials, University of Wollongong, Wollongong, NSW 2522, Australia
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Bennett D, Taylor Z, Tewari P, Sung S, Maccabi A, Singh R, Culjat M, Grundfest W, Hubschman JP, Brown E. Assessment of corneal hydration sensing in the terahertz band: in vivo results at 100 GHz. JOURNAL OF BIOMEDICAL OPTICS 2012; 17:97008-1. [PMID: 23085925 PMCID: PMC3449294 DOI: 10.1117/1.jbo.17.9.097008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Revised: 07/22/2012] [Accepted: 08/14/2012] [Indexed: 05/24/2023]
Abstract
Terahertz corneal hydration sensing has shown promise in ophthalmology applications and was recently shown to be capable of detecting water concentration changes of about two parts in a thousand in ex vivo corneal tissues. This technology may be effective in patient monitoring during refractive surgery and for early diagnosis and treatment monitoring in diseases of the cornea. In this work, Fuchs dystrophy, cornea transplant rejection, and keratoconus are discussed, and a hydration sensitivity of about one part in a hundred is predicted to be needed to successfully distinguish between diseased and healthy tissues in these applications. Stratified models of corneal tissue reflectivity are developed and validated using ex vivo spectroscopy of harvested porcine corneas that are hydrated using polyethylene glycol solutions. Simulation of the cornea's depth-dependent hydration profile, from 0.01 to 100 THz, identifies a peak in intrinsic reflectivity contrast for sensing at 100 GHz. A 100 GHz hydration sensing system is evaluated alongside the current standard ultrasound pachymetry technique to measure corneal hydration in vivo in four rabbits. A hydration sensitivity, of three parts per thousand or better, was measured in all four rabbits under study. This work presents the first in vivo demonstration of remote corneal hydration sensing.
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Affiliation(s)
- David Bennett
- Center for Advanced Surgical and Interventional Technology, Los Angeles, California 90095, USA.
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12
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A robust current pattern for the detection of intraventricular hemorrhage in neonates using electrical impedance tomography. Ann Biomed Eng 2010; 38:2733-47. [PMID: 20238166 DOI: 10.1007/s10439-010-0003-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2009] [Accepted: 03/04/2010] [Indexed: 10/19/2022]
Abstract
We compared two 16-electrode electrical impedance tomography (EIT) current patterns on their ability to reconstruct and quantify small amounts of bleeding inside a neonatal human head using both simulated and phantom data. The current patterns used were an adjacent injection RING pattern (with electrodes located equidistantly on the equator of a sphere) and an EEG current pattern based on the 10-20 EEG electrode layout. Structures mimicking electrically important structures in the infant skull were included in a spherical numerical forward model and their effects on reconstructions were determined. The EEG pattern was found to be a better topology to localize and quantify anomalies within lateral ventricular regions. The RING electrode pattern could not reconstruct anomaly location well, as it could not distinguish different axial positions. The quantification accuracy of the RING pattern was as good as the EEG pattern in noise-free environments. However, the EEG pattern showed better quantification ability than the RING pattern when noise was added. The performance of the EEG pattern improved further with respect to the RING pattern when a fontanel was included in forward models. Significantly better resolution and contrast of reconstructed anomalies was achieved when generated from a model containing such an opening and 50 dB added noise. The EEG method was further applied to reconstruct data from a realistic neonatal head model. Overall, acceptable reconstructions and quantification results were obtained using this model and the homogeneous spherical forward model.
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13
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Sadleir RJ, Neralwala F, Te T, Tucker A. A controllably anisotropic conductivity or diffusion phantom constructed from isotropic layers. Ann Biomed Eng 2009; 37:2522-31. [PMID: 19760146 DOI: 10.1007/s10439-009-9799-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2009] [Accepted: 09/09/2009] [Indexed: 11/30/2022]
Abstract
Phantoms with controllable and well-defined anisotropy are needed to test methods for imaging electrical anisotropy. We developed and tested a phantom that had properties similar to a homogeneous anisotropic conductive medium. The phantom was constructed with alternate slices of isotropic gel having different conductivities. The degree of anisotropy in the phantom could be varied easily by changing the relative conductivity of the two gels. We tested the stability of several phantoms and found their properties were maintained for approximately 8 h following construction. The phantom has application to electrical impedance tomography, magnetic resonance electrical impedance tomography, EEG and ECG source imaging and diffusion tensor imaging.
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Affiliation(s)
- Rosalind J Sadleir
- J. Crayton Pruitt Department of Biomedical Engineering, University of Florida, Gainesville, USA.
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14
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Abstract
Skin cancer is the most common form of cancer types. It is generally divided into two categories: melanoma (∼ 5%) and nonmelanoma (∼ 95%), which can be further categorized into basal cell carcinoma, squamous cell carcinoma, and some rare skin cancer types. Biopsy is still the gold standard for skin cancer evaluation in the clinic. Various anatomical imaging techniques have been used to evaluate different types of skin cancer lesions, including laser scanning confocal microscopy, optical coherence tomography, high-frequency ultrasound, terahertz pulsed imaging, magnetic resonance imaging, and some other recently developed techniques such as photoacoustic microscopy. However, anatomical imaging alone may not be sufficient in guiding skin cancer diagnosis and therapy. Over the last decade, various molecular imaging techniques (in particular single photon emission computed tomography and positron emission tomography) have been investigated for skin cancer imaging. The pathways or molecular targets that have been studied include glucose metabolism, integrin αvβ3, melanocortin-1 receptor, high molecular weight melanoma-associated antigen, and several other molecular markers. Preclinical molecular imaging is thriving all over the world, while clinical molecular imaging has not lived up to the expectations because of slow bench-to-bedside translation. It is likely that this situation will change in the near future and molecular imaging will truly play an important role in personalized medicine of melanoma patients.
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Affiliation(s)
- Hao Hong
- Departments of Radiology and Medical Physics, School of Medicine and Public Health, University of Wisconsin - Madison, Madison, Wisconsin, USA
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15
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Sadleir RJ, Zhang SU, Tucker AS, Oh S. Imaging and quantification of anomaly volume using an eight-electrode 'hemiarray' EIT reconstruction method. Physiol Meas 2008; 29:913-27. [PMID: 18603671 DOI: 10.1088/0967-3334/29/8/005] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Electrical impedance tomography (EIT) is particularly well-suited to applications where its portability, rapid acquisition speed and sensitivity give it a practical advantage over other monitoring or imaging systems. An EIT system's patient interface can potentially be adapted to match the target environment, and thereby increase its utility. It may thus be appropriate to use different electrode positions from those conventionally used in EIT in these cases. One application that may require this is the use of EIT on emergency medicine patients; in particular those who have suffered blunt abdominal trauma. In patients who have suffered major trauma, it is desirable to minimize the risk of spinal cord injury by avoiding lifting them. To adapt EIT to this requirement, we devised and evaluated a new electrode topology (the 'hemiarray') which comprises a set of eight electrodes placed only on the subject's anterior surface. Images were obtained using a two-dimensional sensitivity matrix and weighted singular value decomposition reconstruction. The hemiarray method's ability to quantify bleeding was evaluated by comparing its performance with conventional 2D reconstruction methods using data gathered from a saline phantom. We found that without applying corrections to reconstructed images it was possible to estimate blood volume in a two-dimensional hemiarray case with an uncertainty of around 27 ml. In an approximately 3D hemiarray case, volume prediction was possible with a maximum uncertainty of around 38 ml in the centre of the electrode plane. After application of a QI normalizing filter, average uncertainties in a two-dimensional hemiarray case were reduced to about 15 ml. Uncertainties in the approximate 3D case were reduced to about 30 ml.
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Affiliation(s)
- R J Sadleir
- J Crayton Pruitt Department of Biomedical Engineering, University of Florida, Box 116131, Gainesville, FL, USA.
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16
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Xu J, Plaxco KW, Allen SJ. Collective Dynamics of Lysozyme in Water: Terahertz Absorption Spectroscopy and Comparison with Theory. J Phys Chem B 2006; 110:24255-9. [PMID: 17125398 DOI: 10.1021/jp064830w] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
To directly measure the low-frequency vibrational modes of proteins in biologically relevant water environment rather than previously explored dry or slightly hydrated phase, we have developed a broadband terahertz spectrometer suitable for strongly attenuating protein solutions. Radiation is provided by harmonic multipliers (up to 0.21 THz), a Gunn oscillator (at 0.139 THz), and the UCSB free-electron lasers (up to 4.8 THz). Our spectrometer combines these intense sources with a sensitive cryogenic detector and a variable path length sample cell to detect radiation after it is attenuated by more than 7 orders of magnitudes by the aqueous sample. Using this spectrometer, we have measured the molar extinction of solvated lysozyme between 0.075 and 3.72 THz (2.5-124 cm(-1)), and we made direct comparison to several published theoretical models based on molecular dynamics simulations and normal-mode analysis. We confirm the existence of dense, overlapping normal modes in the terahertz frequency range. Our observed spectrum, while in rough qualitative agreement with these models, differs in detail. Further, we observe a low-frequency cutoff in terahertz dynamics between 0.2 and 0.3 THz, and we see no evidence of a predicted normal mode at approximately 0.09 THz for the protein.
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Affiliation(s)
- Jing Xu
- Department of Physics and Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, USA.
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17
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Xu J, Plaxco KW, Allen SJ. Probing the collective vibrational dynamics of a protein in liquid water by terahertz absorption spectroscopy. Protein Sci 2006; 15:1175-81. [PMID: 16641490 PMCID: PMC2242499 DOI: 10.1110/ps.062073506] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Biological polymers are expected to exhibit functionally relevant, global, and subglobal collective modes in the terahertz (THz) frequency range (i.e., picosecond timescale). In an effort to monitor these collective motions, we have experimentally determined the absorption spectrum of solvated bovine serum albumin (BSA) from 0.3 to 3.72 THz (10-124 cm(-1)). We successfully extract the terahertz molar absorption of the solvated BSA from the much stronger attenuation of water and observe in the solvated protein a dense, overlapping spectrum of vibrational modes that increases monotonically with increasing frequency. We see no evidence of distinct, strong, spectral features, suggesting that no specific collective vibrations dominate the protein's spectrum of motions, consistent with the predictions of molecular dynamics simulations and normal mode analyses of a range of small proteins. The shape of the observed spectrum resembles the ideal quadratic spectral density expected for a disordered ionic solid, indicating that the terahertz normal mode density of the solvated BSA may be modeled, to first order, as that of a three-dimensional elastic nanoparticle with an aperiodic charge distribution. Nevertheless, there are important detailed departures from that of a disordered inorganic solid or the normal mode densities predicted for several smaller proteins. These departures are presumably the spectral features arising from the unique molecular details of the solvated BSA. The techniques used here and measurements have the potential to experimentally confront theoretical calculations on a frequency scale that is important for macromolecular motions in a biologically relevant water environment.
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Affiliation(s)
- Jing Xu
- Department of Physics, University of California, Santa Barbara, California 93106, USA.
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