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Guan Xu, Yafang Xue, Zeynep Gürsel Özkurt, Naziha Slimani, Zizhong Hu, Xueding Wang, Kewen Xia, Teng Ma, Qifa Zhou, Hakan Demirci
The purpose of this study is to examine the capability of photoacoustic (PA) imaging (PAI) in assessing the unique molecular and architectural features in ocular tumors. A real-time PA and ultrasonography (US) parallel imaging system based on a research US platform was developed to examine retinoblastoma in mice in vivo and human retinoblastoma and uveal melanoma ex vivo. PA signals were generated by optical illumination at 720, 750, 800, 850, 900 and 950 nm delivered through a fiber optical bundle. The optical absorption spectra of the tumors were derived from the PA images...
2017: PloS One
Fengli Gao, Maozhong Sun, Wei Ma, Xiaoling Wu, Liqiang Liu, Hua Kuang, Chuanlai Xu
Photodynamic therapy (PDT) agent, which generates singlet oxygen ((1) O2 ) under light, has attracted significant attention for its broad biological and medical applications. Here, DNA-driven shell-satellite (SS) gold assemblies as chiral photosensitizers are first fabricated. The chiral plasmonic nanostructure, coupling with cysteine enantiomers on its surface, exhibits intense chiroplasmonic activities (-40.2 ± 2.6 mdeg) in the visible region. These chiral SS nanoassemblies have high reactive oxygen species generating efficiency under circular polarized light illumination, resulting in a (1) O2 quantum yield of 1...
February 23, 2017: Advanced Materials
K Tachibana, K Okada, R Kobayashi, Y Ishihara, K Tachibana, K Okada, R Kobayashi, Y Ishihara, R Kobayashi, Y Ishihara, K Okada, K Tachibana
We describe the possibility of high-sensitivity noninvasive blood glucose measurement based on photoacoustic spectroscopy (PAS). The demand for noninvasive blood glucose-level measurement has increased due to the explosive increase in diabetic patients. We have developed a noninvasive blood glucose-level measurement based on PAS. The conventional method uses a straight-type resonant cell. However, the cell volume is large, which results in a low detection sensitivity and difficult portability. In this paper, a small-sized Helmholtz-type resonant cell is proposed to improve detection sensitivity and portability by reducing the cell dead volume...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
Joo Yong Sim, Chang-Geun Ahn, Eunju Jeong, Bong Kyu Kim, Joo Yong Sim, Chang-Geun Ahn, Eunju Jeong, Bong Kyu Kim, Bong Kyu Kim, Chang-Geun Ahn, Eunju Jeong, Joo Yong Sim
Glucose measurements using photoacoustic spectroscopy have been highlighted to be a modality for non-invasive glucose monitoring. Previous photoacoustic spectroscopy for glucose measurements have used a resonant acoustic cell with a broadband capacitive microphone to increase sensitivity. However, a resonant characteristic of a microphone has not been investigated yet due to the working frequency range much lower than the resonance frequency of the microphone membrane. We, here, present a photoacoustic spectroscopy system that utilizes an ultrasound resonance of a microphone to increase sensitivity...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
Yu-Hang Liu, Lun-De Liao, Su Jing Chan, Aishwarya Bandla, Nitish V Thakor, Yu-Hang Liu, Lun-De Liao, Su Jing Chan, Aishwarya Bandla, Nitish V Thakor, Yu-Hang Liu, Aishwarya Bandla, Nitish V Thakor, Su Jing Chan, Lun De Liao
Brain ischemia is a neurological deficit caused by a reduction in the blood supply to tissue, and one of the leading causes of disability in the world. Currently, the most well-known therapeutic agent for ischemia recovery is recombinant tissue plasminogen activator (rtPA), but it is viable for only a small portion (approximately 3.6%) of ischemic patients and may cause side effects such as tissue damage. Thus, introducing a new therapeutic concept for ischemia, we proposed an integrated intervention combining global and focal stimulations in this article...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
Israr Ul Haq, Ryo Nagoaka, Takahiro Makino, Takuya Tabata, Yoshifumi Saijo, Israr Ul Haq, Ryo Nagoaka, Takahiro Makino, Takuya Tabata, Yoshifumi Saijo, Ryo Nagoaka, Yoshifumi Saijo, Takahiro Makino, Takuya Tabata
Filtering and segmentation of vasculature is an important issue in medical imaging. The visualization of vasculature is crucial for the early diagnosis and therapy in numerous medical applications. This paper investigates the use of Gabor wavelet to enhance the effect of vasculature while eliminating the noise due to size, sensitivity and aperture of the detector in 3D Optical Resolution Photoacoustic Microscopy (OR-PAM). A detailed multi-scale analysis of wavelet filtering and Hessian based method is analyzed for extracting vessels of different sizes since the blood vessels usually vary with in a range of radii...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
Xun Wu, Jean Lunsford Sanders, Douglas N Stephens, Omer Oralkan, Xun Wu, Jean Lunsford Sanders, Douglas N Stephens, Omer Oralkan, Douglas N Stephens, Jean Lunsford Sanders, Omer Oralkan, Xun Wu
Temperature monitoring during high-intensity focused ultrasound (HIFU) application is necessary to ensure effective therapy while minimizing thermal damage to adjacent tissue. In this study, we demonstrate a noninvasive approach for temperature measurement during HIFU therapy based on photoacoustic imaging (PAI). Because of the dependence of photoacoustic (PA) signal amplitude on temperature of the source tissue and the linearity of the PAI system, changes in temperature will cause changes in PA image intensity...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
Naoki Wadamori, Naoki Wadamori, Naoki Wadamori
Endogenous gas analysis is a potentially fast and convenient noninvasive diagnostic method for a variety of diseases. However, sampling and sample preparation are error-prone steps and must be optimized to achieve reliable results. A miniature photoacoustic system was developed to allow gas sampling using a smart endoscope. The photoacoustic system was demonstrated to have a 1% detection limit for CO2, which is too high. Many improvements, including modifying the structure of PA cell, must be considered for further development...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
Nagaiyan Sekar, Ramaiah D, Yogesh Gawale, Adarsh N, Joseph J, M Pramanik, S K Kalva
Four novel N-ethylcarbazole linked aza-BODIPY dyes (8a-b and 9a-b) were synthesized and characterized. The presence of N-ethylcarbazole moiety shifts their absorption and fluorescence spectra to the near-infrared region, ca. 650-730 nm, of electromagnetic spectra. These dyes possess strong molar absorptivity in the range of 3-4 x 104 M-1cm-1 with low fluorescence quantum yields. The triplet excited state as well as singlet oxygen generation of these dyes were enhanced upon iodination at the core position. The core iodinated dyes 9a-b showed excellent triplet quantum yield of ca...
February 22, 2017: Chemistry: a European Journal
Yi Liu, Sheng Wang, Ying Ma, Jing Lin, Hai-Yan Wang, Yueqing Gu, Xiaoyuan Chen, Peng Huang
Photoacoustic molecular imaging is an emerging and promising diagnostic tool for heavy metal ions detection. Methylmercury (MeHg(+) ) is one of the most potent neurotoxins, which damages the brain and nervous system of human beings through fish consumption. The development of a selective and sensitive method for MeHg(+) detection is highly desirable. In this Communication, we develope a chemoselective photoacoustic sensor (LP-hCy7) composed of the liposome (LP) and MeHg(+) -responsive near-infrared (NIR) cyanine dye (hCy7) for MeHg(+) detection within living subjects, such as zebrafish and mouse...
February 22, 2017: Advanced Materials
Assaf A Gilad, Mikhail G Shapiro
Biomedical synthetic biology is an emerging field in which cells are engineered at the genetic level to carry out novel functions with relevance to biomedical and industrial applications. This approach promises new treatments, imaging tools, and diagnostics for diseases ranging from gastrointestinal inflammatory syndromes to cancer, diabetes, and neurodegeneration. As these cellular technologies undergo pre-clinical and clinical development, it is becoming essential to monitor their location and function in vivo, necessitating appropriate molecular imaging strategies, and therefore, we have created an interest group within the World Molecular Imaging Society focusing on synthetic biology and reporter gene technologies...
February 17, 2017: Molecular Imaging and Biology: MIB: the Official Publication of the Academy of Molecular Imaging
Chao Tian, Ting Feng, Cheng Wang, Shengchun Liu, Qian Cheng, David E Oliver, Xueding Wang, Guan Xu
Most current photoacoustic imaging (PAI) systems employ piezoelectric transducers to receive photoacoustic signals, which requires coupling medium to facilitate photoacoustic wave propagation and are not favored in many applications. Here, we report an all-optical non-contact PAI system based on a commercial heterodyne interferometer working at 1550 nm. The interferometer remotely detects ultrasound-induced surface vibration and does not involve any physical contact with the sample. The theoretically predicated and experimentally measured noise equivalent detection limits of the optical sensor are about 4...
December 1, 2016: IEEE Sensors Journal
Mohesh Moothanchery, Manojit Pramanik
Photoacoustic microscopy (PAM) is a scalable bioimaging modality; one can choose low acoustic resolution with deep penetration depth or high optical resolution with shallow imaging depth. High spatial resolution and deep penetration depth is rather difficult to achieve using a single system. Here we report a switchable acoustic resolution and optical resolution photoacoustic microscopy (AR-OR-PAM) system in a single imaging system capable of both high resolution and low resolution on the same sample. Lateral resolution of 4...
February 12, 2017: Sensors
Fabio A Schaberle, Artur R Abreu, Nuno P F Gonçalves, Gonçalo F F Sá, Mariette M Pereira, Luís G Arnaut
Manganese(III) and manganese(II) complexes of halogenated sulfonamide tetraphenylbacteriochlorins were prepared for the first time via a transmetalation reaction and shown to be stable at room temperature. The behavior of the electronic states of the paramagnetic complexes is remarkably different from those of the metal-free bacteriochlorins or diamagnetic metallobacteriochlorins. The Mn(3+) complex exhibits eight electronic transitions between different states from 300 to 1100 nm, with a very prominent band (molar absorption coefficient of ca...
February 16, 2017: Inorganic Chemistry
Z Su, Y H Bai, X M Hou
OBJECTIVE: To compare the effect of four different techniques on removal of vapor lock in the apical region of curved root canals. METHODS: Forty simulated resin root canals with 45° curvature were prepared using WaveOne Primary, then the apical foramen were sealed with soft wax. The teeth were divided randomly into 4 groups thereafter (n=10). Contract solution was injected into the canals using a 30 G side-vented needle and scanned with cone-beam CT (CBCT) to identify the volume of the vapor lock...
February 18, 2017: Beijing da Xue Xue Bao. Yi Xue Ban, Journal of Peking University. Health Sciences
Dongyel Kang, Bahman Lashkari, Andreas Mandelis
The effect of a spherically focused ultrasound (US) transducer (TD) on photoacoustic (PA) measurements is analytically investigated using the concept of a virtual point detector. The derived analytical results indicate that the limited numerical aperture (NA) of the PA detector takes on the role of spatial filtering of the induced PA waves, which leads to the occurrence of a peak frequency in the PA spectrum. The mathematical description of this phenomenon is similar to the result of resonance peaks of light propagation in dielectrics...
February 15, 2017: Optics Letters
Baptiste Jayet, Jean-Pierre Huignard, Francois Ramaz
Probing local displacements on a scattering surface can be achieved using an adaptive interferometer. The photorefractive-crystal-based interferometer is popular, but alternatives exist such as an adaptive gain interferometer. Such setups take advantage of the nonlinear phenomena in laser media. Because of the gain saturation, it is possible to write a gain hologram and a refractive index hologram to achieve an adaptive interferometer with a linear response. In addition, laser-media-based setups have a fast response time (≤100  μs), which makes them interesting for applications such as detection of photoacoustic waves in living biological samples...
February 15, 2017: Optics Letters
Kenneth J Furdella, Russell S Witte, Jonathan P Vande Geest
No abstract text is available yet for this article.
April 1, 2017: Journal of Biomedical Optics
Mehmet Burak Guneser, Asiye Nur Dincer, Dilara Arslan
OBJECTIVE: The aim of this in vitro study was to compare the various techniques for removing precipitate formed after irrigation with sodium hypochlorite (NaOCl) and chlorhexidine (CHX). BACKGROUND DATA: It is still unclear whether different irrigant activation systems can effectively remove precipitate that is firmly attached to the root canal walls. METHODS: Eighty-two extracted single-rooted human teeth were instrumented by using the ProTaper rotary system...
February 10, 2017: Photomedicine and Laser Surgery
Houjuan Zhu, Zhuangchai Lai, Yuan Fang, Xu Zhen, Chaoliang Tan, Xiaoying Qi, Dan Ding, Peng Chen, Hua Zhang, Kanyi Pu
2D materials (TDMs) have been explored for photonic theranostics. To achieve deep-tissue penetration, near-infrared (NIR) light is essential for photoacoustic (PA) theranostics. However, because the absorption profiles of existing TDMs are generally featureless with no obvious NIR absorption peaks, their PA signals and therapeutic efficacies are limited. This paper herein reports the synthesis and application of ternary chalcogenide nanosheets (Ta2 NiS5 -P) for PA theranostics. In contrast to the current TDMs for such application, Ta2 NiS5 -P has a ternary instead of binary composition...
February 10, 2017: Small
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