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https://www.readbyqxmd.com/read/28920978/a-two-photon-fluorescent-probe-for-ratiometric-imaging-of-endogenous-hypochlorous-acid-in-live-cells-and-tissues
#1
Yong Woong Jun, Sourav Sarkar, Subhankar Singha, Ye Jin Reo, Hye Rim Kim, Jong-Jin Kim, Young-Tae Chang, Kyo Han Ahn
A fluorescent probe that enables ratiometric imaging of endogenous hypochlorous acid (HOCl) in cells and tissues by two-photon microscopy is developed based on a red-emitting acetyl-benzocoumarin (AcBC) dye. An oxathiolane group in the probe reacts with HOCl to generate the AcBC dye, which involves a ratiometric fluorescence change only toward HOCl along with high sensitivity.
September 18, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28919043/neocortical-dynamics-during-whisker-based-sensory-discrimination-in-head-restrained-mice
#2
Fritjof Helmchen, Ariel Gilad, Jerry L Chen
A fundamental task frequently encountered by brains is to rapidly and reliably discriminate between sensory stimuli of the same modality, be it distinct auditory sounds, odors, visual patterns, or tactile textures. A key mammalian brain structure involved in discrimination behavior is the neocortex. Sensory processing not only involves the respective primary sensory area, which is crucial for perceptual detection, but additionally relies on cortico-cortical communication among several regions including higher-order sensory areas as well as frontal cortical areas...
September 14, 2017: Neuroscience
https://www.readbyqxmd.com/read/28918081/developmental-alcohol-exposure-impairs-synaptic-plasticity-without-overtly-altering-microglial-function-in-mouse-visual-cortex
#3
Elissa L Wong, Nina M Lutz, Victoria A Hogan, Cassandra E Lamantia, Helene R McMurray, Jason R Myers, John M Ashton, Ania K Majewska
Fetal alcohol spectrum disorder (FASD), caused by gestational ethanol (EtOH) exposure, is one of the most common causes of non-heritable and life-long mental disability worldwide, with no standard treatment or therapy available. While EtOH exposure can alter the function of both neurons and glia, it is still unclear how EtOH influences brain development to cause deficits in sensory and cognitive processing later in life. Microglia play an important role in shaping synaptic function and plasticity during neural circuit development and have been shown to mount an acute immunological response to EtOH exposure in certain brain regions...
September 13, 2017: Brain, Behavior, and Immunity
https://www.readbyqxmd.com/read/28916873/effects-of-methotrexate-on-the-quality-of-oocyte-maturation-in-vitro
#4
N Tian, J Yu, Sh Zhang, W Y Ma, T Wang, Y M Wang
Methotrexate (MTX), an antifolate drug, is widely used for clinical treatment of malignancies and ectopic pregnancy. Many studies have documented that MTX has strong side-effects on rapidly dividing somatic cells. However, its side-effects on female reproductive cells have not been widely reported. Combined with in vitro culture, two-photon fluorescence imaging and three-dimensional reconstruction, this study analyzed the effects of MTX on oocyte maturation time, chromosome arrangement, karyotype, spindle morphology, and the localization of microtubule organizing centers (MTOCs)...
September 15, 2017: European Biophysics Journal: EBJ
https://www.readbyqxmd.com/read/28915944/a-novel-substrate-inspired-fluorescent-probe-to-monitor-native-albumin-in-human-plasma-and-living-cells
#5
Guang-Bo Ge, Lei Feng, Qiang Jin, Yi-Ru Wang, Zhao-Ming Liu, Xin-Yue Zhu, Ping Wang, Jie Hou, Jing-Nan Cui, Ling Yang
Human albumin (HA) displays crucial roles in maintaining health and fighting diseases. Accurate determination of native HA in plasma or non-plasma samples are of immense significance in both basic research and clinical practice. Herein, a novel ratiometric two-photon fluorescent probe (N-butyl-4-(4-phenyl-benzoyloxy) 1,8-naphthalimide, BPBN) has been designed and developed for highly selective and sensitive sensing the enzymatic activities of HA, on the basis of its unique pseudo-esterase feature. BPBN exhibits excellent selectivity, high sensitivity and good reactivity under physiological conditions...
October 9, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/28915047/two-photon-absorption-in-pentacene-dimers-the-importance-of-the-tether-using-upconversion-as-an-indirect-route-to-singlet-fission
#6
Eleonora Garoni, Johannes Zirzlmeier, Bettina S Basel, Constantin Hetzer, Kenji Kamada, Dirk M Guldi, Rik R Tykwinski
In this proof of concept study, we show that intramolecular singlet fission (iSF) can be initiated from a singlet excited state accessed by two-photon absorption, rather than through a tradition route of direct one-photon excitation (OPE). Thus, iSF in pentacene dimers 2 and 3 is enabled through NIR irradiation at 775 nm, a wavelength where neither dimer exhibits linear absorption of light. The meta-phenylene and adamantyl tethers 2 and 3, respectively, are designed to feature superimposable geometry, which establishes that the electronic coupling between the two pentacenes is the significant structural feature that dictates iSF efficiency...
September 15, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28911321/q-a-the-brain-under-a-mesoscope-the-forest-and-the-trees
#7
Nicholas James Sofroniew
Neurons relevant to a particular behavior are often widely dispersed across the brain. To record activity in groups of individual neurons that might be distributed across large distances, neuroscientists and optical engineers have been developing a new type of microscope called a mesoscope. Mesoscopes have high spatial resolution and a large field of view. This Q&A will discuss this exciting new technology, highlighting a particular instrument, the two-photon random access mesoscope (2pRAM).
September 14, 2017: BMC Biology
https://www.readbyqxmd.com/read/28910617/whole-cell-recording-of-neuronal-membrane-potential-during-behavior
#8
REVIEW
Carl C H Petersen
Neuronal membrane potential is of fundamental importance for the mechanistic understanding of brain function. This review discusses progress in whole-cell patch-clamp recordings for low-noise measurement of neuronal membrane potential in awake behaving animals. Whole-cell recordings can be combined with two-photon microscopy to target fluorescently labeled neurons, revealing cell-type-specific membrane potential dynamics of retrogradely or genetically labeled neurons. Dual whole-cell recordings reveal behavioral modulation of membrane potential synchrony and properties of synaptic transmission in vivo...
September 13, 2017: Neuron
https://www.readbyqxmd.com/read/28910360/transgelin-2-is-upregulated-on-activated-b-cells-and-expressed-in-hyperplastic-follicles-in-lupus-erythematosus-patients
#9
Kaori Kiso, Hajime Yoshifuji, Takuma Oku, Masaki Hikida, Koji Kitagori, Yoshitaka Hirayama, Toshiki Nakajima, Hironori Haga, Tatsuaki Tsuruyama, Aya Miyagawa-Hayashino
Transgelin-2 (TAGLN2) is an actin-binding protein that controls actin stability and promotes T cell activation. TAGLN2 is also expressed on B-cells but its function in B-cells is unknown. We found that TAGLN2-expressing B-cells were localized in the germinal center (GC) of secondary lymphoid tissues and TAGLN2 mRNA was significantly upregulated after IgM+IgG stimulation in primary human B-cells, suggesting that TAGLN2 was upregulated upon B-cell activation. In support of this, lymph nodes (LNs) from patients with systemic lupus erythematosus (SLE), in which the intense GC activity have been recognized, showed increased TAGLN2 expression in B-cells compared to control LNs...
2017: PloS One
https://www.readbyqxmd.com/read/28910077/and-there-was-light-prospects-for-the-creation-of-micro-and-nanostructures-through-maskless-photolithography
#10
J Rühe
In photolithographic processes, the light inducing the photochemical reactions is confined to a small volume, which enables direct writing of micro- and nanoscale features onto solid surfaces without the need of a predefined photomask. The direct writing process can be used to generate topographic patterns through photopolymerization or photo-cross-linking or can be employed to use light to generate chemical patterns on the surface with high spatial control, which would make such processes attractive for bioapplications...
September 14, 2017: ACS Nano
https://www.readbyqxmd.com/read/28904390/quantum-interference-in-the-presence-of-a-resonant-medium
#11
Dmitry A Kalashnikov, Elizaveta V Melik-Gaykazyan, Alexey A Kalachev, Ye Feng Yu, Arseniy I Kuznetsov, Leonid A Krivitsky
Interaction of light with media often occurs with a femtosecond response time. Its measurement by conventional techniques requires the use of femtosecond lasers and sophisticated time-gated optical detection. Here we demonstrate that by exploiting quantum interference of entangled photons it is possible to measure the dephasing time of a resonant media on the femtosecond time scale (down to 100 fs) using accessible continuous wave laser and single-photon counting. We insert a sample in the Hong-Ou-Mandel interferometer and observe the modification of the two-photon interference pattern, which is driven by the coherent response of the medium, determined by the dephasing time...
September 13, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28899087/molecular-ion-formation-by-photo-induced-electron-transfer-at-the-tetracyanoquinodimethane-au-111-interface
#12
David Gerbert, Petra Tegeder
Optically-induced processes in organic materials are essential for light harvesting, switching, and sensor technologies. Here we studied the electronic properties of the tetracyanoquinodimethane(TCNQ)/Au(111) interface by using two-photon photoemission spectroscopy. We found a significant increase of the sample work function due to UV light illumination, while the electronic structure of the TCNQ-derived states remain unaffected. Thereby the work function of this interface can be tuned over a wide range via the photon dose...
September 12, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/28898510/multi-photon-absorption-in-metal-organic-frameworks
#13
Raghavender Medishetty, Lydia Nemec, Venkatram Nalla, Sebastian Henke, Marek Samoc, Karsten Reuter, Roland A Fischer
Multi-photon absorption (MPA) is among the most prominent nonlinear optical (NLO) effects and has applications, for example in telecommunications, defense, photonics and bio-medicines. Established MPA materials include dyes, quantum dots, organometallics and conjugated polymers, most often dispersed in solution. We demonstrate how metal-organic frameworks (MOFs), a novel NLO solid-state materials class, can be designed for exceptionally strong MPA behavior. MOFs consisting of zirconium- and hafnium-oxo-clusters and featuring a chromophore linker based on the tetraphenylethene (TPE) molecule exhibit record high two-photon absorption (2PA) cross section values, up to 3600 GM...
September 12, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28898091/directed-two-photon-absorption-in-cdse-nanoplatelets-revealed-by-k-space-spectroscopy
#14
Jan Heckmann, Riccardo Scott, Anatol V Prudnikau, Artsiom Antanovich, Nina Owschimikow, Mikhail Artemyev, Juan I Climente, Ulrike Woggon, Nicolai B Grosse, Alexander W Achtstein
We show that two-photon absorption (TPA) is highly anisotropic in CdSe nanoplatelets, thus promoting them as a new class of directional two-photon absorbers with large cross sections. Comparing two-dimensional k-space spectroscopic measurements of the one-photon and two-photon excitation of an oriented monolayer of platelets, it is revealed that TPA into the continuum is a directional phenomenon. This is in contrast to one-photon absorption. The observed directional TPA is shown to be related to fundamental band anisotropies of zincblende CdSe and the ultrastrong anisotropic confinement...
September 18, 2017: Nano Letters
https://www.readbyqxmd.com/read/28894365/photothermal-ablation-of-inflammatory-breast-cancer-tumor-emboli-using-plasmonic-gold-nanostars
#15
Bridget M Crawford, Ronnie L Shammas, Andrew M Fales, David A Brown, Scott T Hollenbeck, Tuan Vo-Dinh, Gayathri R Devi
Inflammatory breast cancer (IBC) is rare, but it is the most aggressive subtype of breast cancer. IBC has a unique presentation of diffuse tumor cell clusters called tumor emboli in the dermis of the chest wall that block lymph vessels causing a painful, erythematous, and edematous breast. Lack of effective therapeutic treatments has caused mortality rates of this cancer to reach 20%-30% in case of women with stage III-IV disease. Plasmonic nanoparticles, via photothermal ablation, are emerging as lead candidates in next-generation cancer treatment for site-specific cell death...
2017: International Journal of Nanomedicine
https://www.readbyqxmd.com/read/28891466/thalamic-input-to-auditory-cortex-is-locally-heterogeneous-but-globally-tonotopic
#16
Sebastian A Vasquez-Lopez, Yves Weissenberger, Michael Lohse, Peter Keating, Andrew J King, Johannes C Dahmen
Topographic representation of the receptor surface is a fundamental feature of sensory cortical organization. This is imparted by the thalamus, which relays information from the periphery to the cortex. To better understand the rules governing thalamocortical connectivity and the origin of cortical maps, we used in vivo two-photon calcium imaging to characterize the properties of thalamic axons innervating different layers of mouse auditory cortex. Although tonotopically organized at a global level, we found that the frequency selectivity of individual thalamocortical axons is surprisingly heterogeneous, even in layers 3b/4 of the primary cortical areas, where the thalamic input is dominated by the lemniscal projection...
September 11, 2017: ELife
https://www.readbyqxmd.com/read/28890417/the-impact-of-vessel-size-orientation-and-intravascular-contribution-on-the-neurovascular-fingerprint-of-bold-bssfp-fmri
#17
Mario Gilberto Báez-Yánez, Philipp Ehses, Christian Mirkes, Philbert S Tsai, David Kleinfeld, Klaus Scheffler
Monte Carlo simulations have been used to analyze oxygenation-related signal changes in pass-band balanced steady state free precession (bSSFP) as well as in gradient echo (GE) and spin echo (SE) sequences. Signal changes were calculated for artificial cylinders and neurovascular networks acquired from the mouse parietal cortex by two-photon laser scanning microscopy at 1 μm isotropic resolution. Signal changes as a function of vessel size, blood volume, vessel orientation to the main magnetic field B0 as well as relations of intra- and extravascular and of micro- and macrovascular contributions have been analyzed...
September 7, 2017: NeuroImage
https://www.readbyqxmd.com/read/28889737/selective-and-rapid-detection-of-nitric-oxide-by-a-two-photon-fluorescent-probe-in-live-cells-and-tissue-slices
#18
Chun-Guang Dai, Ji-Long Wang, Ying-Long Fu, Hongping Zhou, Qin-Hua Song
Nitric oxide (NO) is important signaling molecule implicated in numerous physiological and pathological processes. Although numerous NO fluorescent probes have been successfully developed in the past decade, it still remains limitations such as slow response, low selectivity, and short excitation wavelength (< 600 nm). In this Article, a two-photon fluorescent probe, NO-QA5, has been developed with 3-dimethylaminophenyl linking at 6-position of 5-aminoquinoline as both the active site and pre-fluorophore for detection of NO...
September 11, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28888430/vacuum-facilitated-infusion-of-bioactives-into-yeast-microcarriers-evaluation-of-a-novel-encapsulation-approach
#19
Stephen Young, Sharleen Dea, Nitin Nitin
Encapsulation into yeast microcarriers provides an appealing alternative to biomimetic systems by employing natural, pre-formed vehicles for the stabilization and delivery of bioactives compounds. However, current (diffusion-limited) methods of encapsulation using yeast require long time scales and heating which lead to poor encapsulation efficiencies and yields. This study evaluates the usage of vacuum infusion to encapsulate two model bioactives, curcumin and fisetin, into yeast and yeast cell wall particles and the physical parameters, e...
October 2017: Food Research International
https://www.readbyqxmd.com/read/28880900/phase-separation-of-the-plasma-membrane-in-human-red-blood-cells-as-a-potential-tool-for-diagnosis-and-progression-monitoring-of-type-1-diabetes-mellitus
#20
Giuseppe Maulucci, Ermanno Cordelli, Alessandro Rizzi, Francesca De Leva, Massimiliano Papi, Gabriele Ciasca, Daniela Samengo, Giovambattista Pani, Dario Pitocco, Paolo Soda, Giovanni Ghirlanda, Giulio Iannello, Marco De Spirito
Glycosylation, oxidation and other post-translational modifications of membrane and transmembrane proteins can alter lipid density, packing and interactions, and are considered an important factor that affects fluidity variation in membranes. Red blood cells (RBC) membrane physical state, showing pronounced alterations in Type 1 diabetes mellitus (T1DM), could be the ideal candidate for monitoring the disease progression and the effects of therapies. On these grounds, the measurement of RBC membrane fluidity alterations can furnish a more sensitive index in T1DM diagnosis and disease progression than Glycosylated hemoglobin (HbA1c), which reflects only the information related to glycosylation processes...
2017: PloS One
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