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https://www.readbyqxmd.com/read/28938466/optogenetic-analysis-of-depolarization-dependent-glucagon-like-peptide-1-release
#1
Catalin Chimerel, Cristian Riccio, Keir Murison, Fiona M Gribble, Frank Reimann
Incretin hormones play an important role in the regulation of food intake and glucose homeostasis. Glucagon-like peptide-1 (GLP-1) secreting cells have been demonstrated to be electrically excitable and to fire action potentials (APs) with increased frequency in response to nutrient exposure. However, nutrients can also be metabolised or activate G-protein-coupled receptors, thus potentially stimulate GLP-1 secretion independent of their effects on the plasma membrane potential. Here we used channelrhodopsins to manipulate the membrane potential of GLUTag cells, a well established model of GLP-1 secreting enteroendocrine L-cells...
July 28, 2017: Endocrinology
https://www.readbyqxmd.com/read/28938168/energy-transfer-and-color-tunable-emission-in-tb-3-eu-3-co-doped-sr3lana-po4-3f-phosphors
#2
Shuo Li, Ning Guo, Qimeng Liang, Yu Ding, Huitao Zhou, Ruizhuo Ouyang, Wei Lü
A group of color tunable Sr3LaNa(PO4)3F:Tb(3+),Eu(3+) phosphors were prepared by conventional high temperature solid state method. The phase structures, luminescence properties, fluorescence lifetimes and energy transfer were investigated in detail. Under 369nm excitation, owing to efficient energy transfer of Tb(3+)→Eu(3+), the emission spectra both have green emission of Tb(3+) and red emission of Eu(3+). An efficient energy transfer occur in Tb(3+), Eu(3+) co-doped Sr3LaNa(PO4)3F phosphors. The most possible mechanism of energy transfer is dipole-dipole interaction by Dexter's theoretical model...
September 18, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28938074/native-electron-capture-dissociation-maps-to-iron-binding-channels-in-horse-spleen-ferritin
#3
Owen S Skinner, Michael O McAnally, Richard P Van Duyne, George C Schatz, Kathrin Breuker, Philip D Compton, Neil L Kelleher
Native electron capture dissociation (NECD) is a process during which proteins undergo fragmentation similar to that from radical dissociation methods, but without the addition of exogenous electrons. However, after three initial reports of NECD from the cytochrome c dimer complex, no further evidence of the effect has been published. Here, we report NECD behavior from horse spleen ferritin, a ~490 kDa protein complex ~20-fold larger than the previously studied cytochrome c dimer. Application of front-end infrared excitation (FIRE) in conjunction with low- and high-m/z quadrupole isolation and collisionally activated dissociation (CAD) provides new insights into the NECD mechanism...
September 22, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28938046/the-value-that-infectious-diseases-physicians-bring-to-the-healthcare-system
#4
Daniel P McQuillen, Ann T MacIntyre
While a career in infectious diseases (ID) has always been challenging and exciting, recognition of the value that ID physicians provide to the healthcare system as a whole, over and above the value they provide to individual patients, has been poor in this system. In response to this disparity, the Infectious Diseases Society of America Clinical Affairs Committee has long endeavored to quantify the value of ID physicians to the system, which is challenging in part because of the many avenues through which they influence healthcare...
September 15, 2017: Journal of Infectious Diseases
https://www.readbyqxmd.com/read/28938044/sunday-in-the-park-with-infectious-disease-workforce-mismatch-in-a-colorful-universe-of-possibilities
#5
Thomas Moore, Louise-Marie Dembry, Michael S Saag
The decline in applications for infectious diseases (ID) fellowships has been an area of active introspection for the leadership of the Infectious Disease Society of America (IDSA). This prompted actions to address the problem, including surveys of current and former fellows. Ironically, the decline in applications to ID programs is occurring at a time when the need for ID providers has never been greater and the excitement and variety in the practice of ID has never been higher. Data regarding the current ID workforce are presented here, along with perspectives about the future of the profession in the decades to come...
September 15, 2017: Journal of Infectious Diseases
https://www.readbyqxmd.com/read/28938009/altering-neuronal-excitability-to-preserve-network-connectivity-in-a-computational-model-of-alzheimer-s-disease
#6
Willem de Haan, Elisabeth C W van Straaten, Alida A Gouw, Cornelis J Stam
Neuronal hyperactivity and hyperexcitability of the cerebral cortex and hippocampal region is an increasingly observed phenomenon in preclinical Alzheimer's disease (AD). In later stages, oscillatory slowing and loss of functional connectivity are ubiquitous. Recent evidence suggests that neuronal dynamics have a prominent role in AD pathophysiology, making it a potentially interesting therapeutic target. However, although neuronal activity can be manipulated by various (non-)pharmacological means, intervening in a highly integrated system that depends on complex dynamics can produce counterintuitive and adverse effects...
September 22, 2017: PLoS Computational Biology
https://www.readbyqxmd.com/read/28937970/spectroscopy-and-enhanced-frequency-upconversion-in-nd-3-yb-3-codoped-tpo-glasses-energy-transfer-and-nir-to-visible-upconverter
#7
Mohd Azam, Vineet Kumar Rai, Deepak Kumar Mohanty
TeO2-Pb3O4 (TPO) glasses codoped with Nd(3+) and Yb(3+) ions have been fabricated by conventional melting technique. The absorption, emission and excitation spectra of the samples have been recorded. The optical band gap in both the doped/codoped glasses is found to be ∼3.31 eV. Judd-Ofelt analysis has been carried out by using the absorption spectrum of 0.8 mol% Nd(3+) doped glass to determine the radiative properties viz radiative transition probabilities, branching ratios, radiative lifetimes, quality factor and emission cross sections of some emitting levels for Nd(3+) ions...
September 22, 2017: Methods and Applications in Fluorescence
https://www.readbyqxmd.com/read/28937969/layered-double-hydroxide-enhanced-luminescence-in-a-fenton-like-system-for-selective-sensing-of-cobalt-in-hela-cells
#8
Mei Yu, Zhiqin Yuan, Chao Lu
This work presented a facile and eco-friendly method for the determination of cobalt ions (Co(II)) in living cells based on layered double hydroxides (Mg-Al CO3-LDHs) enhanced chemiluminescence (CL) emission of a Co(II)-hydrogen peroxide-sodium hydroxide system. The enhanced CL emission was attributed to the large specific surface area of Mg-Al CO3-LDHs, which facilitates the generation of an excited-stated intermediate. The proposed method displayed high selectivity toward Co(II) over other metal ions. Under the optimal conditions, the increased CL intensity showed a linear response versus Co(II) concentration in the range of 5...
September 22, 2017: Methods and Applications in Fluorescence
https://www.readbyqxmd.com/read/28937772/terahertz-light-matter-interaction-beyond-unity-coupling-strength
#9
Andreas Bayer, Marcel Pozimski, Simon Schambeck, Dieter Schuh, Rupert Huber, Dominique Bougeard, Christoph Lange
Achieving control over light-matter interaction in custom-tailored nanostructures is at the core of modern quantum electrodynamics. In strongly and ultrastrongly coupled systems, the excitation is repeatedly exchanged between a resonator and an electronic transition at a rate known as the vacuum Rabi frequency ΩR. For ΩR approaching the resonance frequency ωc, novel quantum phenomena including squeezed states, Dicke superradiant phase transitions, the collapse of the Purcell effect, and a population of the ground state with virtual photon pairs are predicted...
September 22, 2017: Nano Letters
https://www.readbyqxmd.com/read/28937696/chromophores-of-chromophores-a-bottom-up-h%C3%A3-ckel-picture-of-the-excited-states-of-photoactive-proteins
#10
Cate S Anstöter, Charlie R Dean, Jan R R Verlet
Many photoactive proteins contain chromophores based on para-substituted phenolate anions which are an essential component of their electronic structure. Here, we present a reductionist approach to gain fundamental insight into the evolution of electronic structure as the chromophore increases in complexity from phenolate to that in GFP. Using frequency- and angle-resolved photoelectron spectroscopy, in combination with electronic structure theory, the onset of excited states that are responsible for the characteristic spectroscopic features in biochromophores are determined...
September 22, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28937675/coherent-singlet-fission-activated-by-symmetry-breaking
#11
Kiyoshi Miyata, Yuki Kurashige, Kazuya Watanabe, Toshiki Sugimoto, Shota Takahashi, Shunsuke Tanaka, Jun Takeya, Takeshi Yanai, Yoshiyasu Matsumoto
Singlet fission, in which a singlet exciton is converted to two triplet excitons, is a process that could be beneficial in photovoltaic applications. A full understanding of the dynamics of singlet fission in molecular systems requires detailed knowledge of the relevant potential energy surfaces and their (conical) intersections. However, obtaining such information is a nontrivial task, particularly for molecular aggregates. Here we investigate singlet fission in rubrene crystals using transient absorption spectroscopy and state-of-the-art quantum chemical calculations...
October 2017: Nature Chemistry
https://www.readbyqxmd.com/read/28937587/%C3%A2%C2%B5-conotoxins-modulating-sodium-currents-in-pain-perception-and-transmission-a-therapeutic-potential
#12
REVIEW
Elisabetta Tosti, Raffaele Boni, Alessandra Gallo
The Conus genus includes around 500 species of marine mollusks with a peculiar production of venomous peptides known as conotoxins (CTX). Each species is able to produce up to 200 different biological active peptides. Common structure of CTX is the low number of amino acids stabilized by disulfide bridges and post-translational modifications that give rise to different isoforms. µ and µO-CTX are two isoforms that specifically target voltage-gated sodium channels. These, by inducing the entrance of sodium ions in the cell, modulate the neuronal excitability by depolarizing plasma membrane and propagating the action potential...
September 22, 2017: Marine Drugs
https://www.readbyqxmd.com/read/28937579/pyrethroids-inhibit-k2p-channels-and-activate-sensory-neurons-basis-of-insecticide-induced-paraesthesias
#13
Aida Castellanos, Alba Andres, Laura Bernal, Gerard Callejo, Nuria Comes, Arcadi Gual, Jonathan P Giblin, Carolina Roza, Xavier Gasull
Pyrethroid insecticides are widely used for pest control, in agriculture or in human public health commonly as a topical treatment for scabies and head lice. Exposure to pyrethroids such as permethrin or tetramethrin (TM) causes sensory alterations such as transient pain, burning, stinging sensations and paraesthesias. Despite the well-known effects of pyrethroids on sodium channels, actions on other channels that control sensory neuron excitability are less studied. Given the role of two-pore domain potassium (K2P) channels in modulating sensory neuron excitability and firing, both in physiological and pathological conditions, we examined the effect of pyrethroids on K2P channels mainly expressed in sensory neurons...
September 19, 2017: Pain
https://www.readbyqxmd.com/read/28937215/infrared-spectroscopy-of-the-entrance-channel-complex-formed-between-the-hydroxyl-radical-and-methane-in-helium-nanodroplets
#14
Paul L Raston, Emmanuel I Obi, Gary E Douberly
The entrance channel complex in the exothermic OH + CH4 → H2O + CH3 reaction has been isolated in helium nanodroplets following the sequential pick-up of the hydroxyl radical and methane. The a-type OH stretching band was probed with infrared depletion spectroscopy, revealing a qualitatively similar spectrum to that previously reported in the gas phase, but with additional substructure that is due to the different internal rotation states of methane (jCH4 = 0, 1, or 2) in the complex. We fit the spectra by assuming the rotational constants of the complex are the same for all internal rotation states; however, subband origins are found to decrease with increasing jCH4...
September 22, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28937122/an-exciting-time-ahead
#15
(no author information available yet)
No abstract text is available yet for this article.
September 22, 2017: British Dental Journal
https://www.readbyqxmd.com/read/28936654/imaging-ca-2-dynamics-in-wild-type-and-nadph-oxidase-deficient-mutant-pollen-tubes-with-yellow-cameleon-and-confocal-laser-scanning-microscopy
#16
Christina Maria Franck, Jens Westermann, Aurélien Boisson-Dernier
While cytosolic calcium (Ca(2+)) plays a central role in a myriad of signaling pathways as a secondary messenger, how dynamic changes of cytosolic calcium relate to cell growth control remains poorly understood. The engineering and continuous improvements of genetically encoded calcium sensors such as the Yellow Cameleon (YC) sensors combined with advances in microscopy have allowed imaging with great resolution of the spatiotemporal characteristics of cytosolic [Ca(2+)]cyt in individual cells. An exciting new step consists therefore in cautiously studying calcium dynamics in mutant backgrounds that display disturbed cellular growth behavior to further enhance our understanding on growth-related processes...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/28936518/microscopic-time-resolved-imaging-of-singlet-oxygen-by-delayed-fluorescence-in-living-cells
#17
Marek Scholz, Roman Dědic, Jan Hála
Singlet oxygen is a highly reactive species which is involved in a number of processes, including photodynamic therapy of cancer. Its very weak near-infrared emission makes imaging of singlet oxygen in biological systems a long-term challenge. We address this challenge by introducing Singlet Oxygen Feedback Delayed Fluorescence (SOFDF) as a novel modality for semi-direct microscopic time-resolved wide-field imaging of singlet oxygen in biological systems. SOFDF has been investigated in individual fibroblast cells incubated with a well-known photosensitizer aluminium phthalocyanine tetrasulfonate...
September 22, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28935962/excitation-of-coupled-spin-orbit-dynamics-in-cobalt-oxide-by-femtosecond-laser-pulses
#18
Takuya Satoh, Ryugo Iida, Takuya Higuchi, Yasuhiro Fujii, Akitoshi Koreeda, Hiroaki Ueda, Tsutomu Shimura, Kazuo Kuroda, V I Butrim, B A Ivanov
Ultrafast control of magnets using femtosecond light pulses attracts interest regarding applications and fundamental physics of magnetism. Antiferromagnets are promising materials with magnon frequencies extending into the terahertz range. Visible or near-infrared light interacts mainly with the electronic orbital angular momentum. In many magnets, however, in particular with iron-group ions, the orbital momentum is almost quenched by the crystal field. Thus, the interaction of magnons with light is hampered, because it is only mediated by weak unquenching of the orbital momentum by spin-orbit interactions...
September 21, 2017: Nature Communications
https://www.readbyqxmd.com/read/28935842/the-paralogs-to-the-c-terminal-domain-of-the-cyanobacterial-ocp-are-carotenoid-donors-to-hcps
#19
Fernando Muzzopappa, Adjélé Wilson, Vinosa Yogarajah, Sandrine Cot, François Perreau, Cédric Montigny, Céline Bourcier de Carbon, Diana Kirilovsky
The photoactive Orange Carotenoid Protein photoprotects cyanobacteria cells by quenching singlet oxygen and excess excitation energy. Its N-terminal domain (NTD) is the active part of the protein and the C-terminal domain (CTD) regulates the activity. Recently, the characteristics of a family of soluble carotenoid-binding proteins (Helical Carotenoid Proteins or HCPs), paralogs of NTD-OCP, were described. Bioinformatics studies also revealed the existence of genes coding for homologs of CTD. Here, we show that the latter genes encode carotenoid proteins (CTDHs)...
September 21, 2017: Plant Physiology
https://www.readbyqxmd.com/read/28935776/liquid-phase-condensation-in-cell-physiology-and-disease
#20
REVIEW
Yongdae Shin, Clifford P Brangwynne
Phase transitions are ubiquitous in nonliving matter, and recent discoveries have shown that they also play a key role within living cells. Intracellular liquid-liquid phase separation is thought to drive the formation of condensed liquid-like droplets of protein, RNA, and other biomolecules, which form in the absence of a delimiting membrane. Recent studies have elucidated many aspects of the molecular interactions underlying the formation of these remarkable and ubiquitous droplets and the way in which such interactions dictate their material properties, composition, and phase behavior...
September 22, 2017: Science
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