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Infrared Imaging

Anurag Mishra, Yuanyuan Jiang, Sheryl Roberts, Vasilis Ntziachristos, Gil Gregor Westmeyer
Photoacoustic imaging (PAI) is an attractive imaging modality that can volumetrically map the distribution of photoabsorbing molecules with deeper tissue penetration than multiphoton microscopy. To enable dynamic sensing of divalent cations via PAI, we have engineered a new reversible near infrared probe that is more sensitive to calcium as compared to other biologically relevant cations. The metallochromic compound showed a strong reduction of its peak absorbance at 765 nm upon addition of calcium ions that was translated into robust signal changes in photoacoustic images...
October 25, 2016: Analytical Chemistry
Carina Barbosa Pereira, Xinchi Yu, Michael Czaplik, Vladimir Blazek, Boudewijn Venema, Steffen Leonhardt
Diverse studies have demonstrated the importance of monitoring breathing rate (BR). Commonly, changes in BR are one of the earliest and major markers of serious complications/illness. However, it is frequently neglected due to limitations of clinically established measurement techniques, which require attachment of sensors. The employment of adhesive pads or thoracic belts in preterm infants as well as in traumatized or burned patients is an additional paramount issue. The present paper proposes a new robust approach, based on data fusion, to remotely monitor BR using infrared thermography (IRT)...
October 24, 2016: Journal of Clinical Monitoring and Computing
Chrystelle Neaime, Maria Amela-Cortes, Fabien Grasset, Yann Molard, Stéphane Cordier, Benjamin Dierre, Michel Mortier, Toshiaki Takei, Kohsei Takahashi, Hajime Haneda, Marc Verelst, Séverine Lechevallier
Bioimaging and cell labeling using red or near infrared phosphors emitting in the "therapeutic window" of biological tissues have recently become some of the most active research fields in modern medical diagnostics. However, because organic and inorganic autofluorophores are omnipresent in nature, very often the background signal from fluorochromes other than targeted probes has to be eliminated. This discrimination could be available using a time-gated luminescence microscopy (TGLM) technique associated with long lifetime phosphorescent nanocomposites...
October 25, 2016: Physical Chemistry Chemical Physics: PCCP
Bjørn Hagen, Marit Valla, Guro Aune, Merethe Ravlo, Anne Britt Abusland, Elisabeth Araya, Marit Sundset, Solveig Tingulstad
OBJECTIVE: A sentinel lymph node (SLN) strategy may have particular value in endometrial cancer (EC) because a therapeutic effect of lymphadenectomy per se is unproven. The aim was to evaluate indocyanine green (ICG) and near-infrared (NIR) fluorescence mapping using a surgical algorithm. METHODS: From November 2012 through December 2015, women with apparently early stage EC underwent robot-assisted laparoscopic hysterectomy including ICG fluorescence SLN mapping following the Memorial Sloane Kettering Cancer Center (MSKCC) surgical algorithm...
October 21, 2016: Gynecologic Oncology
Tobias Stauber, Heinerich Kohler
The charge susceptibility of twisted bilayer graphene is investigated in the Dirac cone, respectively random-phase approximation. For small enough twist angles Θ≦2(o) we find weakly Landau damped interband plasmons, i.~e., collective excitonic modes which exist in the undoped material, with an almost constant energy dispersion. In this regime, the loss function can be described as a Fano resonance and we argue that these excitations arise from the interaction of quasi-localised states with the incident light field...
October 24, 2016: Nano Letters
Pablo Alonso-González, Alexey Y Nikitin, Yuanda Gao, Achim Woessner, Mark B Lundeberg, Alessandro Principi, Nicolò Forcellini, Wenjing Yan, Saül Vélez, Andreas J Huber, Kenji Watanabe, Takashi Taniguchi, Félix Casanova, Luis E Hueso, Marco Polini, James Hone, Frank H L Koppens, Rainer Hillenbrand
Terahertz (THz) fields are widely used for sensing, communication and quality control. In future applications, they could be efficiently confined, enhanced and manipulated well below the classical diffraction limit through the excitation of graphene plasmons (GPs). These possibilities emerge from the strongly reduced GP wavelength, λp, compared with the photon wavelength, λ0, which can be controlled by modulating the carrier density of graphene via electrical gating. Recently, GPs in a graphene/insulator/metal configuration have been predicted to exhibit a linear dispersion (thus called acoustic plasmons) and a further reduced wavelength, implying an improved field confinement, analogous to plasmons in two-dimensional electron gases (2DEGs) near conductive substrates...
October 24, 2016: Nature Nanotechnology
Rui Zhang, Shiping Zhu, Qin Zhou
Infrared image segmentation is a challenging topic because infrared images are characterized by high noise, low contrast, and weak edges. Active contour models, especially gradient vector flow, have several advantages in terms of infrared image segmentation. However, the GVF (Gradient Vector Flow) model also has some drawbacks including a dilemma between noise smoothing and weak edge protection, which decrease the effect of infrared image segmentation significantly. In order to solve this problem, we propose a novel generalized gradient vector flow snakes model combining GGVF (Generic Gradient Vector Flow) and NBGVF (Normally Biased Gradient Vector Flow) models...
October 21, 2016: Sensors
Mauro Zaninelli, Veronica Redaelli, Erica Tirloni, Cristian Bernardi, Vittorio Dell'Orto, Giovanni Savoini
The development of a monitoring system to identify the presence of laying hens, in a closed room of a free-range commercial organic egg production farm, was the aim of this study. This monitoring system was based on the infrared (IR) technology and had, as final target, a possible reduction of atmospheric ammonia levels and bacterial load. Tests were carried out for three weeks and involved 7 ISA (Institut de Sélection Animale) brown laying hens. The first 5 days was used to set up the detection sensor, while the other 15 days were used to evaluate the accuracy of the resulting monitoring system, in terms of sensitivity and specificity...
October 21, 2016: Sensors
Eugenio Ivorra, Samuel Verdu, Antonio J Sánchez, Raúl Grau, José M Barat
A technique that combines the spatial resolution of a 3D structured-light (SL) imaging system with the spectral analysis of a hyperspectral short-wave near infrared system was developed for freshness predictions of gilthead sea bream on the first storage days (Days 0-6). This novel approach allows the hyperspectral analysis of very specific fish areas, which provides more information for freshness estimations. The SL system obtains a 3D reconstruction of fish, and an automatic method locates gilthead's pupils and irises...
October 19, 2016: Sensors
Akio Hayashi, Hiromi Ota, Xavier López, Norihito Hiyoshi, Nao Tsunoji, Tsuneji Sano, Masahiro Sadakane
Dipotassium cation (K(+))-encapsulated Preyssler-type phosphotungstate, [P5W30O110K2](13-), was prepared by heating monobismuth (Bi(3+))-encapsulated Preyssler-type phosphotungstate, [P5W30O110Bi(H2O)](12-), in acetate buffer in the presence of an excess amount of potassium cations. Characterization of the isolated potassium salt, K13[P5W30O110K2] (1a), and its acid form, H13[P5W30O110K2] (1b), by single crystal X-ray structure analysis, (31)P and (183)W nuclear magnetic resonance (NMR), Fourier transform infrared (FT-IR) spectroscopy, cyclic voltammetry (CV), high-resolution electrospray ionization mass spectroscopy (HR-ESI-MS), and elemental analysis revealed that two potassium cations are encapsulated in the Preyssler-type phosphotungstate molecule with formal D5h symmetry, which is the first example of a Preyssler-type compound with two encapsulated cations...
October 24, 2016: Inorganic Chemistry
Xiaofeng Wu, Lihong Li, Wen Shi, Qiuyu Gong, Huimin Ma
Fluorescence imaging of tyrosinase (a cancer biomarker) in living organisms is of great importance for biological studies. However, selective detection of tyrosinase remains a great challenge because current fluorescent probes that contain the 4-hydroxyphenyl moiety show similar fluorescence responses to both tyrosinase and some reactive oxygen species (ROS), thereby suffering from ROS interference. Herein, a new tyrosinase-recognition 3-hydroxybenzyloxy moiety, which exhibits distinct fluorescence responses for tyrosinase and ROS, is proposed...
October 24, 2016: Angewandte Chemie
Shuai Yu, Bingbing Cheng, Tingfeng Yao, Cancan Xu, Kytai T Nguyen, Yi Hong, Baohong Yuan
Recently, we developed a new technology, ultrasound-switchable fluorescence (USF), for high-resolution imaging in centimeter-deep tissues via fluorescence contrast. The success of USF imaging highly relies on excellent contrast agents. ICG-encapsulated poly(N-isopropylacrylamide) nanoparticles (ICG-NPs) are one of the families of the most successful near-infrared (NIR) USF contrast agents. However, the first-generation ICG-NPs have a short shelf life (<1 month). This work significantly increases the shelf life of the new-generation ICG-NPs (>6 months)...
October 24, 2016: Scientific Reports
Nivethaa E A K, Dhanavel S, Narayanan V, Stephen A
Fluorescent CS/Ag-Au (chitosan/silver-gold) nanocomposite containing different weight percentage of Ag and Au was synthesized using the chemical reduction method. 5-Fluorouracil (5-FU) encapsulated nanocomposite was also synthesized and its cytotoxicity towards breast cancer cell lines (MCF-7) studied. The XRD pattern of the nanocomposite shows peaks of chitosan, silver and gold. The peaks corresponding to gold and silver indicate the face centered cubic structure of silver and gold nanoparticles. The polymer matrix nanocomposite structure with chitosan as the matrix and silver-gold as the filler phase is evident from the high resolution transmission electron microscopy (HRTEM) images and an increase in particle size from∼5nm to about 12nm is noticeable on encapsulation of 5-Fluorouracil (5-FU)...
October 20, 2016: International Journal of Biological Macromolecules
Tao Li, Xiufen Chen, Yajun Liu, Lulu Fan, Liqing Lin, Yu Xu, Sijia Chen, Jingwei Shao
Ursolic acid (UA) as a nature product exhibits good anti-cancer activity, low toxicity, and good liver protection features. However, the low-solubility and poor bioavailability restrict its further clinical application. To overcome this problem, a pH-sensitive prodrug delivery system (UA@MSN-UA) that incorporated acid-sensitive linkage between drug and silica-based mesoporous nanosphere (MSN) was successfully designed and synthesized. The physicochemical properties of the UA@MSN-UA nanoparticles were investigated for shape, particle size, zeta potential, nitrogen adsorption-desorption and infrared (IR) spectroscopy...
October 19, 2016: European Journal of Pharmaceutical Sciences
Kayla Presley, Jinwoo Hwang, Soshan Cheong, Richard Tilley, Josh Collins, Mariano Viapiano, John Lannutti
Optical oxygen sensors have many promising qualities but rely on excitation by violet or blue wavelengths that suffer from high levels of scattering and absorption in biological tissues. Here we demonstrate an alternative method using 980nm near-infrared light to initially stimulate ceramic upconverting nanoparticles (UCNPs) contained within a novel form, electrospun core-shell fibers. The emission of the UCNPs excites a molecular optical oxygen sensor, the subsequent phosphorescent emission being dynamically quenched by the presence of molecular oxygen...
January 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
Claure N Lunardi, Anderson J Gomes, Sandeep Palepu, P Thilanka Galwaduge, Elizabeth M C Hillman
Here we present the production, characterization and in-vivo assessment of cresyl violet-loaded biodegradable PLGA nano/microparticles (CV-NP and CV-MP). We demonstrate that the beneficial spectral characteristics of cresyl violet make it suitable as a tracer for particle-based drug delivery using both hyperspectral wide field and two-photon excited fluorescence microscopy. Particles were prepared using a cosolvent method, after which the physicochemical properties such as morphology, particle size, drug entrapment efficiency, drug loading and in vitro drug release behavior were measured in addition to spectroscopic properties, such as absorption, fluorescence and infrared spectra...
January 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
Yang Sheng, Lun-De Liao, Aishwarya Bandla, Yu-Hang Liu, Jun Yuan, Nitish Thakor, Mei Chee Tan
Near-infrared photoacoustic (PA) imaging is an emerging diagnostic technology that utilizes the tissue transparent window to achieve improved contrast and spatial resolution for deep tissue imaging. In this study, we investigated the enhancement effect of the SiO2 shell on the PA property of our core/shell rare-earth nanoparticles (REs) consisting of an active rare-earth doped core of NaYF4:Yb,Er (REDNPs) and an undoped NaYF4 shell. We observed that the PA signal amplitude increased with SiO2 shell thickness...
January 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
Fu-Yan Xing, Lin-Lin Guan, Yan-Long Li, Chun-Juan Jia
This work reports a one-step simple synthesis method for functionalized reduced graphene oxide (RGO) nanosheets by a Platanus orientalis leaf extract polyphenol-mediated deoxygenation of graphene oxide (GO). Microscopic and spectroscopic characterization revealed the successful deoxygenation of GO and subsequent stabilization by oxidized polyphenols of plant extract. X-ray photoelectron spectroscopy, Raman spectroscopy, and X-ray diffraction analyses were used to examine the reduction of GO. Fourier-transform infrared spectroscopy results revealed capping of RGO with oxidized polyphenols of Platanus orientalis extract, which prevented aggregation of graphene sheets...
October 3, 2016: Environmental Toxicology and Pharmacology
Xiuli Chen, Hao Chen, Chunyan Lu, Chao Yang, Xiaoqi Yu, Kun Li, Yongmei Xie
In this report, the design of two novel nitrogen mustard-based DNA cross-linking agents with fluorophores incorporated into the structure (TN-A and TN-B) is disclosed. The results indicate that TN-A and TN-B can serve directly as both reporting and imaging agents for flow cytometry and gel electrophoresis without the necessity of another fluorescent tagging agents. TN-A and TN-B both selectively locate in the mitochondria and exhibit good antitumor activity. Notably, TN-A is the first DNA crosslinking agent with near infrared fluorescence emission properties...
December 1, 2016: Talanta
Ang Li, Xiang Li, Xujiang Yu, Wei Li, Ruyi Zhao, Xiao An, Daxiang Cui, Xiaoyuan Chen, Wanwan Li
In this work, we report a successful synthesis of copper bismuth sulfide nanorods (NRs) with broad and strong photoabsorption ranging from ultraviolet (UV) to near-infrared (NIR) wavelengths, which can be used as a 1064 nm-laser-driven photothermal agent with the photothermal conversion efficiency of 40.7%, noticeably higher than most of the reported PTT agents working in NIR-II window. The as-prepared PEGylated Cu3BiS3 NRs were used as photoacoustic imaging (PAI) and CT imaging agents due to their strong NIR absorption and large X-ray attenuation coefficient of bismuth...
October 12, 2016: Biomaterials
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