Non-invasive observation of spatiotemporal activity of large neural populations distributed over entire brains is a longstanding goal of neuroscience.We developed a volumetric multispectral optoacoustic tomography pla...Non-invasive observation of spatiotemporal activity of large neural populations distributed over entire brains is a longstanding goal of neuroscience.We developed a volumetric multispectral optoacoustic tomography platform for imaging neural activation deep in scattering brains.It can record 100 volumetric frames per second across scalable fields of view ranging between 50 and 1000 mm^(3) with respective spatial resolution of 35–200μm.Experiments performed in immobilized and freely swimming larvae and in adult zebrafish brains expressing the genetically encoded calcium indicator GCaMP5G demonstrate,for the first time,the fundamental ability to directly track neural dynamics using optoacoustics while overcoming the longstanding penetration barrier of optical imaging in scattering brains.The newly developed platform thus offers unprecedented capabilities for functional whole-brain observations of fast calcium dynamics;in combination with optoacoustics'well-established capacity for resolving vascular hemodynamics,it could open new vistas in the study of neural activity and neurovascular coupling in health and disease.展开更多
A noncontact photoacoustic technique using air transducers in MHz range is presented.Firstly, theoretical simulation and experimental fabrication of ultrasonic transducers in airare considered. An improvement of about...A noncontact photoacoustic technique using air transducers in MHz range is presented.Firstly, theoretical simulation and experimental fabrication of ultrasonic transducers in airare considered. An improvement of about 50 dB in the round-trip insertion loss and a frac-tional bandwidth greater than 15% are obtained by using one or two matching layers. Then,the 1 MHz photoacoustic measurement system is described and different applications are dis-cussed. The phase shifts of the received acoustic waves are extracted to obtain the surfacetopography of samples. The ion implantation dose in semiconductor is measured by detectingthe photoacoustic signal in air. Finally, a photoacoustic method for quantitative determina-tion of thin-film thicknesses is proposed.展开更多
The diagnosis of osteoporosis is eventually converted to the measurement of bone mineral density(BMD)in clinical trials.Since our previous work had proved the ability of using photoacoustic spectral analysis(PASA)to e...The diagnosis of osteoporosis is eventually converted to the measurement of bone mineral density(BMD)in clinical trials.Since our previous work had proved the ability of using photoacoustic spectral analysis(PASA)to efficiently detect osteoporosis,in this contribution,we proposed a fully connected multi-layer deep neural network combined with PASA to semi-quantify BMD values corresponding to varying degrees of bone loss and to further evaluate the degree of osteoporosis.Experiments were carried out on swine femur heads,and the performance of our proposed method is satisfying for future clinical screening.展开更多
Photosynthesis rates in phytoplankton depend on light intensity and its spectral composition, however their relation changes with photoacclimation. During the photoacclimation process algal cells optimize their har-ve...Photosynthesis rates in phytoplankton depend on light intensity and its spectral composition, however their relation changes with photoacclimation. During the photoacclimation process algal cells optimize their har-vesting and utilization of available light through series of related physical, biophysical, biochemical and physiological changes. These changes result in the ability of phytoplankton to survive under dim light when transported to the depth of the water column and avoid photodynamic damage when exposed to the intense radiation at the surface. Any reduction in the efficiency of light utilization results in decreased rates of pho-tosynthesis rate and slow growth. We present here the study of changes in photosynthetic energy storage efficiency of three phytoplankton species upon photoacclimation to low and high light, as measured by photo-acoustics. Our results illustrate the power of photoacoustics as a tool in aquatic ecology and in the physiological research of phytoplankton.展开更多
Malaria is one of the leading causes of mortality and morbidity in developing countries. Accurate and complete diagnosis is key for effective treatment of the disease. However, mainstream malaria diagnostic techniques...Malaria is one of the leading causes of mortality and morbidity in developing countries. Accurate and complete diagnosis is key for effective treatment of the disease. However, mainstream malaria diagnostic techniques suffer from a number of shortcomings. There is therefore an urgent need for development of new and more efficient techniques for malaria diagnosis. In vivo Photoacoustic spectroscopy is an emerging technique, which has great potential of delivering a nearly ideal method for early diagnosis of the disease. The technique promises to be highly sensitive and specific. In this paper, a description of photoacoustic malaria sensing is given. This is followed by a review of photoacoustic-based malaria diagnostic techniques and suggestions for future improvements.展开更多
The oxygen evolution, thermal dissipation, and photochemical energy storage of three hybrid poplar clones, namely the triploid clone B342, the diploid clone B11 [(Populus alba×P. glandulosa)×(P.tomentosa...The oxygen evolution, thermal dissipation, and photochemical energy storage of three hybrid poplar clones, namely the triploid clone B342, the diploid clone B11 [(Populus alba×P. glandulosa)×(P.tomentosa×P.bolleana)], and the triploid clone B346 [(P.tomentosa×P. bolleana)×(P. alba×P.glandulosa)], under light stress were studied using photoacoustics. The oxygen evolution signal and photochemical energy storage varied negatively with the pretreatment_PFD (photon flux density), whereas the thermal signal varied positively with the pretreatment_PFD. Photochemical energy storage was reallocated to PSⅡ more than to PSⅠ, while the photochemical energy storage in PSⅠ was more stable than that in PSⅡ when subjected to light stress. The inhibitors streptomycin (SM), dithiothreitol (DTT) and sodium fluoride (NaF) could all affect the oxygen evolution signal. Clones B11 and B342 were more resistant to light stress than clone B346.展开更多
Photoacoustic Doppler flow measurement based on continuous wave laser excitation owns the merit of clearly presenting the Doppler power spectra.Extending this technique to dual wavelengths can gain the spectral inform...Photoacoustic Doppler flow measurement based on continuous wave laser excitation owns the merit of clearly presenting the Doppler power spectra.Extending this technique to dual wavelengths can gain the spectral information of the flow sample extra to the flow speed information.An experimental system with two laser diodes respectively operated at 405 nm and 660 nm wavelengths is built and the flow measurement with black and red dyed polystyrene beads is performed.The measured Doppler power spectra can vividly reflect the flow speed,the flow direction,as well as the bead color.Since it is straightforward to further apply the same principle to multiple wavelengths,we can expect this type of spectroscopic photoacoustic Doppler flow measurement will be developed in the near future which will be very useful for studying the metabolism of the slowly moving red blood cell inside microvessels.展开更多
Whole-body optical imaging of post-embryonic stage model organisms is a challenging and long sought-after goal.It requires a combination of high-resolution performance and high-penetration depth.Optoacoustic(photoacou...Whole-body optical imaging of post-embryonic stage model organisms is a challenging and long sought-after goal.It requires a combination of high-resolution performance and high-penetration depth.Optoacoustic(photoacoustic)mesoscopy holds great promise,as it penetrates deeper than optical and optoacoustic microscopy while providing high-spatial resolution.However,optoacoustic mesoscopic techniques only offer partial visibility of oriented structures,such as blood vessels,due to a limited angular detection aperture or the use of ultrasound frequencies that yield insufficient resolution.We introduce 3601 multi orientation(multi-projection)raster scan optoacoustic mesoscopy(MORSOM)based on detecting an ultra-wide frequency bandwidth(up to 160 MHz)and weighted deconvolution to synthetically enlarge the angular aperture.We report unprecedented isotropic inplane resolution at the 9–17μm range and improved signal to noise ratio in phantoms and opaque 21-day-old Zebrafish.We find that MORSOM performance defines a new operational specification for optoacoustic mesoscopy of adult organisms,with possible applications in the developmental biology of adulthood and aging.展开更多
The photoacoustic effect was employed to generate short-duration quasi-unipolar acoustic pressure pulses in both planar and spherically focused geometries.In the focal region,the temporal profile of a pressure pulse c...The photoacoustic effect was employed to generate short-duration quasi-unipolar acoustic pressure pulses in both planar and spherically focused geometries.In the focal region,the temporal profile of a pressure pulse can be approximated by the first derivative of the temporal profile near the front transducer surface,with a time-averaged value equal to zero.This approximation agreed with experimental results acquired from photoacoustic transducers with both rigid and free boundaries.For a free boundary,the acoustic pressure in the focal region is equal to the sum of a positive pressure that follows the spatial profile of the optical energy deposition in the medium and a negative pressure that follows the temporal profile of the laser pulse.展开更多
基金support from the European Research Council ERC-2010-StG-260991(DR)and ERC-2012-StG_20111109(AL and GGW)the National Institute of Health R21-EY026382-01(DR and SS)+1 种基金the German-Israeli Foundation(GIF)for Scientific Research and Development 1142-46.10/2011(DR and SS)the Helmholtz Association of German Research Centers and the Technische Universität München(DR and GGW)。
文摘Non-invasive observation of spatiotemporal activity of large neural populations distributed over entire brains is a longstanding goal of neuroscience.We developed a volumetric multispectral optoacoustic tomography platform for imaging neural activation deep in scattering brains.It can record 100 volumetric frames per second across scalable fields of view ranging between 50 and 1000 mm^(3) with respective spatial resolution of 35–200μm.Experiments performed in immobilized and freely swimming larvae and in adult zebrafish brains expressing the genetically encoded calcium indicator GCaMP5G demonstrate,for the first time,the fundamental ability to directly track neural dynamics using optoacoustics while overcoming the longstanding penetration barrier of optical imaging in scattering brains.The newly developed platform thus offers unprecedented capabilities for functional whole-brain observations of fast calcium dynamics;in combination with optoacoustics'well-established capacity for resolving vascular hemodynamics,it could open new vistas in the study of neural activity and neurovascular coupling in health and disease.
基金Project supported by the National Foundation of China for post-doctoral researches.
文摘A noncontact photoacoustic technique using air transducers in MHz range is presented.Firstly, theoretical simulation and experimental fabrication of ultrasonic transducers in airare considered. An improvement of about 50 dB in the round-trip insertion loss and a frac-tional bandwidth greater than 15% are obtained by using one or two matching layers. Then,the 1 MHz photoacoustic measurement system is described and different applications are dis-cussed. The phase shifts of the received acoustic waves are extracted to obtain the surfacetopography of samples. The ion implantation dose in semiconductor is measured by detectingthe photoacoustic signal in air. Finally, a photoacoustic method for quantitative determina-tion of thin-film thicknesses is proposed.
基金supported by the National Key Research and Development Program of China(No.2017YFC0111402)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(No.19KJB510031)the Natural Science Foundation of Jiangsu Province(No.BK20181256)。
文摘The diagnosis of osteoporosis is eventually converted to the measurement of bone mineral density(BMD)in clinical trials.Since our previous work had proved the ability of using photoacoustic spectral analysis(PASA)to efficiently detect osteoporosis,in this contribution,we proposed a fully connected multi-layer deep neural network combined with PASA to semi-quantify BMD values corresponding to varying degrees of bone loss and to further evaluate the degree of osteoporosis.Experiments were carried out on swine femur heads,and the performance of our proposed method is satisfying for future clinical screening.
文摘Photosynthesis rates in phytoplankton depend on light intensity and its spectral composition, however their relation changes with photoacclimation. During the photoacclimation process algal cells optimize their har-vesting and utilization of available light through series of related physical, biophysical, biochemical and physiological changes. These changes result in the ability of phytoplankton to survive under dim light when transported to the depth of the water column and avoid photodynamic damage when exposed to the intense radiation at the surface. Any reduction in the efficiency of light utilization results in decreased rates of pho-tosynthesis rate and slow growth. We present here the study of changes in photosynthetic energy storage efficiency of three phytoplankton species upon photoacclimation to low and high light, as measured by photo-acoustics. Our results illustrate the power of photoacoustics as a tool in aquatic ecology and in the physiological research of phytoplankton.
文摘Malaria is one of the leading causes of mortality and morbidity in developing countries. Accurate and complete diagnosis is key for effective treatment of the disease. However, mainstream malaria diagnostic techniques suffer from a number of shortcomings. There is therefore an urgent need for development of new and more efficient techniques for malaria diagnosis. In vivo Photoacoustic spectroscopy is an emerging technique, which has great potential of delivering a nearly ideal method for early diagnosis of the disease. The technique promises to be highly sensitive and specific. In this paper, a description of photoacoustic malaria sensing is given. This is followed by a review of photoacoustic-based malaria diagnostic techniques and suggestions for future improvements.
文摘The oxygen evolution, thermal dissipation, and photochemical energy storage of three hybrid poplar clones, namely the triploid clone B342, the diploid clone B11 [(Populus alba×P. glandulosa)×(P.tomentosa×P.bolleana)], and the triploid clone B346 [(P.tomentosa×P. bolleana)×(P. alba×P.glandulosa)], under light stress were studied using photoacoustics. The oxygen evolution signal and photochemical energy storage varied negatively with the pretreatment_PFD (photon flux density), whereas the thermal signal varied positively with the pretreatment_PFD. Photochemical energy storage was reallocated to PSⅡ more than to PSⅠ, while the photochemical energy storage in PSⅠ was more stable than that in PSⅡ when subjected to light stress. The inhibitors streptomycin (SM), dithiothreitol (DTT) and sodium fluoride (NaF) could all affect the oxygen evolution signal. Clones B11 and B342 were more resistant to light stress than clone B346.
基金This work is supported by the National Natural Science Foundation of China(Grant No.11774256)the Natural Science Foundation of Guangdong Province(Grant No.2018B03031104).
文摘Photoacoustic Doppler flow measurement based on continuous wave laser excitation owns the merit of clearly presenting the Doppler power spectra.Extending this technique to dual wavelengths can gain the spectral information of the flow sample extra to the flow speed information.An experimental system with two laser diodes respectively operated at 405 nm and 660 nm wavelengths is built and the flow measurement with black and red dyed polystyrene beads is performed.The measured Doppler power spectra can vividly reflect the flow speed,the flow direction,as well as the bead color.Since it is straightforward to further apply the same principle to multiple wavelengths,we can expect this type of spectroscopic photoacoustic Doppler flow measurement will be developed in the near future which will be very useful for studying the metabolism of the slowly moving red blood cell inside microvessels.
基金sponsored by the Federal Ministry of Education and Research,Photonic Science Germany,Tech2See-13N12624.
文摘Whole-body optical imaging of post-embryonic stage model organisms is a challenging and long sought-after goal.It requires a combination of high-resolution performance and high-penetration depth.Optoacoustic(photoacoustic)mesoscopy holds great promise,as it penetrates deeper than optical and optoacoustic microscopy while providing high-spatial resolution.However,optoacoustic mesoscopic techniques only offer partial visibility of oriented structures,such as blood vessels,due to a limited angular detection aperture or the use of ultrasound frequencies that yield insufficient resolution.We introduce 3601 multi orientation(multi-projection)raster scan optoacoustic mesoscopy(MORSOM)based on detecting an ultra-wide frequency bandwidth(up to 160 MHz)and weighted deconvolution to synthetically enlarge the angular aperture.We report unprecedented isotropic inplane resolution at the 9–17μm range and improved signal to noise ratio in phantoms and opaque 21-day-old Zebrafish.We find that MORSOM performance defines a new operational specification for optoacoustic mesoscopy of adult organisms,with possible applications in the developmental biology of adulthood and aging.
基金sponsored in part by National Institutes of Health Grant Nos.R01 EB000712 and R01 NS46214(BRP).
文摘The photoacoustic effect was employed to generate short-duration quasi-unipolar acoustic pressure pulses in both planar and spherically focused geometries.In the focal region,the temporal profile of a pressure pulse can be approximated by the first derivative of the temporal profile near the front transducer surface,with a time-averaged value equal to zero.This approximation agreed with experimental results acquired from photoacoustic transducers with both rigid and free boundaries.For a free boundary,the acoustic pressure in the focal region is equal to the sum of a positive pressure that follows the spatial profile of the optical energy deposition in the medium and a negative pressure that follows the temporal profile of the laser pulse.
