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Jiwen Jian, Shu-Xian Hu, Wan-Lu Li, Michael J van Stipdonk, Jonathan Martens, Giel Berden, Jos Oomens, Jun Li, John K Gibson
The following gas-phase uranyl/12-crown-4 (12C4) complexes were synthesized by electrospray ionization: [UO2 (12C4)2 ]2+ and [UO2 (12C4)2 (OH)]+ . Collision-induced dissociation (CID) of the dication resulted in [UO2 (12C4-H)]+ (12C4-H is a 12C4 that has lost one H), which spontaneously adds water to yield [UO2 (12C4-H)(H2 O)]+ . The latter has the same composition as complex [UO2 (12C4)(OH)]+ produced by CID of [UO2 (12C4)2 (OH)]+ but exhibits different reactivity with water. The postulated structures as isomeric [UO2 (12C4-H)(H2 O)]+ and [UO2 (12C4)(OH)]+ were confirmed by comparison of infrared multiphoton dissociation (IRMPD) spectra with computed spectra...
March 20, 2018: Inorganic Chemistry
Samuel D Clark, Rachel Mikofsky, Jacqueline Lawson, David Sulzer
Multiphoton microscopy has been widely adapted for imaging neurons in vivo. Repeated imaging requires implantation of a cranial window or repeated thinning of the skull. Cranial window surgery is typically performed with a high speed rotary drill, and many investigators find it challenging to prevent the drill from damaging the delicate dura and blood vessels. Extensive training and practice is required to remove the bone without damage to underlying tissue and thus cranial window surgery can be difficult, time consuming, and produce tissue damage...
March 2, 2018: Journal of Visualized Experiments: JoVE
Seung Won Jun, Junyoung Kwon, Soo Kyung Chun, Hyun Ah Lee, Jaebeom Lee, Dae Youn Hwang, Chen-Yuan Dong, Chang-Seok Kim
Owing to its near infrared (NIR) absorption, graphene oxide (GO) is promising for both photothermal (PT) therapy and multiphoton (MP) imaging. Novel therapy/imaging modality switching is proposed here based on the selected excitation wavelength of femtosecond (FS) laser. GO-based destruction of cancer cells is demonstrated when the laser power of 800-nm-wavelength FS laser is increased above 7 mW. However, GO-based imaging is mainly monitored without damaging the sample when using 1200-nm wavelength FS laser in the same laser power range...
February 1, 2018: Biomedical Optics Express
Xi Li, Hui Li, Xingzhen He, Tingai Chen, Xianyuan Xia, Chunxia Yang, Wei Zheng
Early identification of premalignant and malignant gastric mucosa is crucial to decrease the incidence and mortality of stomach cancer. Spectrum- and time-resolved multiphoton microscopy are capable of providing not only structural but also biochemical information at the subcellular level. Based on this multidimensional imaging technique, we performed a systematic investigation on fresh human tissue specimens at the typical stages of gastric carcinogenesis, including normal, chronic gastritis with erosion, chronic gastritis with intestinal metaplasia, and intestinal-type adenocarcinoma...
February 1, 2018: Biomedical Optics Express
Alexander Mikhaylov, Sophie de Reguardati, Jüri Pahapill, Patrik R Callis, Bern Kohler, Aleksander Rebane
Fluorescent DNA base analogs and intrinsic fluorophores are gaining importance for multiphoton microscopy and imaging, however, their quantitative nonlinear excitation properties have been poorly documented. Here we present the two-photon absorption (2PA) spectra of 2-aminopurine (2AP), 7-methyl guanosine (7MG), isoxanthopterin (IXP), 6-methyl isoxanthopterin (6MI), as well as L-tryptophan (L-trp) and 3-methylindole (3MI) in aqueous solution and some organic solvents measured in the wavelength range 550 - 810 nm using femtosecond two-photon excited fluorescence (2PEF) and nonlinear transmission (NLT) methods...
February 1, 2018: Biomedical Optics Express
James R Thunes, Julie A Phillippi, Thomas G Gleason, David A Vorp, Spandan Maiti
High lethality of aortic dissection necessitates accurate predictive metrics for dissection risk assessment. The not infrequent incidence of dissection at aortic diameters <5.5 cm, the current threshold guideline for surgical intervention (Nishimura et al., 2014), indicates an unmet need for improved evidence-based risk stratification metrics. Meeting this need requires a fundamental understanding of the structural mechanisms responsible for dissection evolution within the vessel wall. We present a structural model of the repeating lamellar structure of the aortic media comprised of elastic lamellae and collagen fiber networks, the primary load-bearing components of the vessel wall...
February 8, 2018: Journal of Biomechanics
Joshua H Marks, Timothy B Ward, Michael A Duncan
Manganese oxide cluster cations are produced by laser vaporization in a pulsed nozzle source, and detected with time-of-flight mass spectrometry. The mass spectrum contains intense peaks for stoichiometries corresponding to (MnO)n+. Multiphoton photodissociation of these clusters yields smaller ions with the same stoichiometric ratio, either by sequential elimination of MnO units or by various fission processes with roughly equal efficiencies. Fragmentation of clusters containing excess oxygen also yields (MnO)n+ fragments...
March 14, 2018: Journal of Physical Chemistry. A
Hiba Natsheh, Elka Touitou
The goal of this work was to investigate a new nasal carrier for enhanced drug delivery to brain, we call Phospholipid Magnesome. The system contains soft phospholipid vesicles, composed of phospholipid, water, propylene glycol, magnesium salt, and the mucoadhesive polymer, alginate. The carrier was characterized by various methods: electron microscopy, calorimetry, and dynamic light scattering. The ability of the carrier's vesicles to entrap various molecules was studied by CLSM and ultracentrifugation combined with HPLC quantification...
March 9, 2018: Drug Delivery and Translational Research
Claudio Iacobucci, Samantha Reale, Massimiliano Aschi, Jos Oomens, Giel Berden, Francesco De Angelis
Brønsted acids and protic solvents mediate acyl transfer, known as Mumm rearrangement, from imidates to the corresponding acylamides. This represents a key step in several reactions, e.g. the Ugi-four component reaction (U-4CR) and Passerini-three component reaction (P-3CR). Herein we report an unprecedented break of the non-reversibility of the Mumm rearrangement. A combination of electrospray tandem mass spectrometry (ESI-MS/MS), infrared multiphoton dissociation (IRMPD) ion spectroscopy and theoretical calculations demonstrates the occurrence of the retro-Mumm rearrangement of protonated isopeptides in the gas-phase...
March 8, 2018: Chemistry: a European Journal
Andrea Filippi, Eleonora Dal Sasso, Laura Iop, Andrea Armani, Michele Gintoli, Marco Sandri, Gino Gerosa, Filippo Romanato, Giulia Borile
Label-free microscopy is a very powerful technique that can be applied to study samples with no need for exogenous fluorescent probes, keeping the main benefits of multiphoton microscopy, such as longer penetration depths and intrinsic optical sectioning while enabling serial multitechniques examinations on the same specimen. Among the many label-free microscopy methods, harmonic generation (HG) is one of the most intriguing methods due to its generally low photo-toxicity and relative ease of implementation...
March 2018: Journal of Biomedical Optics
Chi Ching Goh, Maximilien Evrard, Shu Zhen Chong, Yingrou Tan, Leonard De Li Tan, Karen Wei Weng Teng, Wolfgang Weninger, David Laurence Becker, Hong Liang Tey, Evan William Newell, Bin Liu, Lai Guan Ng
Pressure ulcers are a chronic problem for patients or the elderly who require extended periods of bed rest. The formation of ulcers is due to repeated cycles of ischemia-reperfusion (IR), which initiates an inflammatory response. Advanced ulcers disrupt the skin barrier, resulting in further complications. To date, the immunological aspect of skin IR has been understudied, partly due to the complexity of the skin immune cells. Through a combination of mass cytometry, confocal imaging and intravital multiphoton imaging, this study establishes a workflow for multidimensionality single cell analysis of skin myeloid responses in the context of IR injury with high spatiotemporal resolution...
March 6, 2018: European Journal of Immunology
Amel Slimani, Delphine Tardivo, Ivan V Panayotov, Bernard Levallois, Csilla Gergely, Frederic Cuisinier, Hervé Tassery, Thierry Cloitre, Elodie Terrer
Dentin carious lesion is a dynamic process that involves demineralization and collagen denaturation. Collagen type I is the major protein in dentin and it has been investigated based on its optical properties. Multiphoton microscopy (MPM) is a nonlinear imaging technique that reveals the caries process using the collagen two-photon excitation fluorescence (2PEF) and its second-harmonic generation (SHG). Combining the histological and the International Caries Detection and Assessment System (ICDAS) classifications with nonlinear optical spectroscopy (NLOS), 2PEF and SHG intensities of enamel and dentin were highly altered during the caries process...
March 6, 2018: Caries Research
Hequn Wang, Thomas Shyr, Michael J Fevola, Gabriela Oana Cula, Georgios N Stamatas
Two-photon fluorescence (TPF) and second harmonic generation (SHG) microscopy provide direct visualization of the skin dermal fibers in vivo. A typical method for analyzing TPF/SHG images involves averaging the image intensity and therefore disregarding the spatial distribution information. The goal of this study is to develop an algorithm to document age-related effects of the dermal matrix. TPF and SHG images were acquired from the upper inner arm, volar forearm, and cheek of female volunteers of two age groups: 20 to 30 and 60 to 80 years of age...
March 2018: Journal of Biomedical Optics
Roberta Galli, Matthias Meinhardt, Edmund Koch, Gabriele Schackert, Gerald Steiner, Matthias Kirsch, Ortrud Uckermann
Label-free multiphoton imaging constitutes a promising technique for clinical diagnosis and therapeutic monitoring. Corpora amylacea (CoA) are starch-like structures often found in the diseased brain, whose origin and role in nervous pathologies are still a matter of debate. Recently, CoA in the diseased human hippocampus were found to be second harmonic generation (SHG) active. Here, we show that CoA formed in other parts of the diseased brain and in brain neoplasms display a similar SHG activity. The SHG pattern of CoA depended on laser polarization, indicating that a radial structure is responsible for their nonlinear activity...
February 28, 2018: Biomedizinische Technik. Biomedical Engineering
Y X Li, S J Montague, A Brüstle, X F He, C Gillespie, K Gaus, E E Gardiner, W M Lee
In this paper, we introduce two key improvements that overcome limitations of existing polygon scanning microscopes whilst maintaining high spatial and temporal imaging resolution over large fields of view (FOV). First, we proposed a simple and straightforward means to control the scanning angle of the polygon mirror to carry out photomanipulation without resorting to high speed optical modulators. Second, we devised a flexible data sampling method directly leading to higher image contrast by over 2 folds and digital images with 100 megapixels (10240 x 10240) per frame at 0...
February 28, 2018: Journal of Biophotonics
Bostjan Markelc, Elisabeth Bellard, Gregor Sersa, Tanja Jesenko, Sandrine Pelofy, Justin Teissié, Robert Frangez, Marie-Pierre Rols, Maja Cemazar, Muriel Golzio
Delivery of electric field pulses, i.e. electroporation (EP), to tissues has been shown to have a blood flow modifying effect. Indeed, the diameter of blood vessels exposed to EP is immediately reduced resulting in blood flow abrogation, followed by an increase in vascular permeability. The main cause of the increased permeability remains unknown. The aim of this study was to determine whether the in vivo effects of EP on permeability of blood vessels are linked to the permeabilization of endothelial cells' membrane (EC) and/or disruption of cell-to-cell junctions...
February 21, 2018: Journal of Controlled Release: Official Journal of the Controlled Release Society
Wataru Ikeda, Ken Sasai, Tsuyoshi Akagi
Most of preclinical cancer studies use xenograft models established from human cell lines or patient-derived cancer cells subcutaneously implanted into the flank of immunocompromised mice. These models are often assumed to represent the original diseases and are valuable tools, at least to some extent, for understanding both the basic biology of cancer and for proof-of-concept studies of molecularly targeted therapies. However, analyzing the cellular behavior of individual components within xenografts, including tumor cells, stromal cells, immune cells, and blood vessels, is challenging...
2018: Methods in Molecular Biology
Sayaka Matsumoto, Junichi Kikuta, Masaru Ishii
The liver is a vital organ in the body. It has various essential functions, including detoxification, protein synthesis, and control of infection. Because of its medical importance, liver diseases such as hepatitis and cirrhosis can be crucial for an individual. Exploring dynamics of living cells in the liver would provide the clues for understanding the pathology. However, due to its technical difficulty, few studies have used intravital liver imaging. To resolve this, we have established a novel imaging system for visualizing liver cell dynamics in living animals...
2018: Methods in Molecular Biology
Jackson LiangYao Li, Chi Ching Goh, Lai Guan Ng
The skin is one of the most physiologically important organs where the organism comes into contact with the external environment and is often a site where pathogen entry first occurs. Thus, a better understanding of the specialized cellular behavior of the immune system in the skin may be important for the improved treatment of diseases. Here, we describe in detail a procedure to image the dorsal mouse ear skin, using a customized ear stage and its associated coverslip holder, with an upright multiphoton microscope...
2018: Methods in Molecular Biology
Asuka Sakata, Satoshi Nishimura
Bone imaging using multiphoton microscopy enables dynamic observation of platelet formation in living animals. Two-photon excitation microscopy is superior to confocal microscopy as it enables deeper tissue penetration, efficient light detection, and reduced phototoxicity. Using this microscopy approach, thrombopoiesis by megakaryocytes is clearly visualized in the skull at significant depth from the surface. Here we describe our microscopy setup and dye recipe for visualization of bone marrow in the mouse skull...
2018: Methods in Molecular Biology
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