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https://www.readbyqxmd.com/read/28103527/distinct-cortico-striatal-connections-with-subthalamic-nucleus-underlie-facets-of-compulsivity
#1
Laurel S Morris, Kwangyeol Baek, Valerie Voon
The capacity to flexibly respond to contextual changes is crucial to adapting to a dynamic environment. Compulsivity, or behavioural inflexibility, consists of heterogeneous subtypes with overlapping yet discrete neural substrates. The subthalamic nucleus (STN) mediates the switch from automatic to controlled processing to slow, break or stop behaviour when necessary. Rodent STN lesions or inactivation are linked with perseveration or repetitive, compulsive responding. However, there are few studies examining the role of latent STN-centric neural networks and compulsive behaviour in healthy individuals...
December 29, 2016: Cortex; a Journal Devoted to the Study of the Nervous System and Behavior
https://www.readbyqxmd.com/read/28103024/hexacarbonyls-of-mo-w-and-sg-metal-co-bonding-revisited
#2
Miroslav Iliaš, Valeria Pershina
Calculations of the first bond dissociation energies (FBDEs) and other molecular properties of M(CO)6, where M = Mo, W, and Sg, have been performed using a variety of nonrelativistic and relativistic methods, such as ZORA-DFT, X2c+AMFI-CCSD(T), and Dirac-Coulomb density functional theory. The aim of the study is to assist experiments on the measurements of the FBDE of Sg(CO)6. We have found that, different from the results published earlier, the metal-CO bond in Sg(CO)6 should be weaker than that in W(CO)6...
January 19, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28102691/thermodynamic-and-kinetic-stabilities-of-g-quadruplexes-in-apolar-solvents
#3
Elham Fadaei, Miguel Martín-Arroyo, Mohsen Tafazzoli, David González-Rodríguez
In contrast to more polar media, G-quadruplex assembly reveals remarkably high thermodynamic and kinetic stability in toluene solutions. Depending on the substituents installed at the lipophilic guanosine, either a dodecamer or an octamer complex is formed in the presence of K(+) or Na(+) salts that resist conditions of high dilution and elevated temperatures without exhibiting significant dissociation. Moreover, kinetic exchange between complexed and uncomplexed G is slow enough in NMR to monitor G-quadruplex formation along a day time scale...
January 19, 2017: Organic Letters
https://www.readbyqxmd.com/read/28102421/the-nature-of-the-light-absorption-and-emission-transitions-of-4-hydroxybenzophenone-in-different-solvents-a-combined-computational-and-experimental-study
#4
Francesco Barsotti, Giovanni Ghigo, Silvia Berto, Davide Vione
The photophysics and photochemistry of 4-hydroxybenzophenone (4HOBP) are interesting because they can give some insight into the behavior of humic material. Here we show that 4HOBP has a number of fluorescence peaks: (i) an intense one at excitation/emission wavelengths Ex/Em ∼ 200-230/280-370 nm, likely due to an excitation transition from S0 to S5 or S6, followed by S2 → S0 in emission (Sn denotes the singlet states of 4HOBP); (ii) a minor peak at Ex/Em ∼ 270-300/320-360 nm (S0 → S2 in absorption and S2 → S0 in emission), and (iii) very interesting signals in the typical emission region of humic substances, most notably at Ex/Em ∼ 200-220/400-500 nm and Ex/Em ∼ 260-280/400-470 nm (in both cases the emission corresponded to an S1 → S0 transition)...
January 19, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28102391/enhancement-in-catalytic-proton-reduction-by-an-internal-base-in-a-diiron-pentacarbonyl-complex-its-synthesis-characterisation-inter-conversion-and-electrochemical-investigation
#5
Zhimei Li, Zhiyin Xiao, Fenfen Xu, Xianghua Zeng, Xiaoming Liu
The reaction of a tripodal ligand (H2L) with a {S2N} donor-set with tri-iron dodecacarbonyl in toluene leads to the isolation of a diiron pentacarbonyl complex 1 as a model for the sub-site of the [FeFe]-hydrogenase. Protonation of this complex under CO (1 atm.) forms quantitatively the hexacarbonyl complex 2H+ with a pendant pyridinium group. Infrared spectroscopic investigations indicate that its pendant pyridinium group dissociates to give hexacarbonyl complex 2 which forms subsequently the pentacarbonyl complex 1...
January 19, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28102390/reactions-in-silicon-nitrogen-plasma
#6
Goran Kovačević, Branko Pivac
Reaction mechanisms that lead to creation of silicon-nitrogen bonds are studied in detail. These reactions are of fundamental importance for silicon nitride synthesis by plasma enhanced chemical vapour deposition from the gas mixture of silane (SiH4) and ammonia (NH3). All reactions in SiH4-NH3 plasma can be categorised as some of the basic types of reactions: bond dissociation, neutral nucleophilic substitution, radical neutralisation, neutral-radical addition, silylene addition, silylene rearrangement, radical nucleophilic addition or hydrogen abstraction reaction...
January 19, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28102077/boosting-hot-electron-generation-exciton-dissociation-at-the-order-disorder-interfaces-in-polymeric-photocatalysts
#7
Hui Wang, Xianshun Sun, Dandan Li, Xiaodong Zhang, Shichuan Chen, Wei Shao, Yupeng Tian, Yi Xie
Excitonic effects, arising from the Coulomb interactions between photogenerated electrons and holes, dominate the optical excitation properties of semiconductors, whereas their influences on photocatalytic processes have seldom been discussed. In view of the competitive generation of exciton and hot carrier, exciton dissociation herein was proposed as an alternative strategy for hot-carrier harvesting in photocatalysts. Herein, by taking heptazine-based melon as an example, we verified that enhanced hot-carrier generation could be obtained in semicrystalline polymeric photocatalysts that contain abundant order-disorder interfaces, ascribing to the accelerated exciton dissociation...
January 19, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28101575/identification-of-potential-targets-for-differentiation-in-human-leukemia-cells-induced-by-diallyl-disulfide
#8
Hui Ling, Jie He, Hui Tan, Lan Yi, Fang Liu, Xiaoxia Ji, Youhua Wu, Haobin Hu, Xi Zeng, Xiaohong Ai, Hao Jiang, Qi Su
Diallyl disulfide (DADS) is a primary component of garlic, which has chemopreventive potential. We previously found that moderate doses (15-120 µM) of DADS induced apoptosis and G2/M phase cell cycle arrest. In this study, we observed the effect of low doses (8 µM) of DADS on human leukemia HL-60 cells. We found that DADS could inhibit proliferation, migration and invasion in HL-60 cells, and arrested cells at G0/G1 stage. Then, cell differentiation was displayed by morphologic observation, NBT reduction activity and CD11b evaluation of cytometric flow...
February 2017: International Journal of Oncology
https://www.readbyqxmd.com/read/28100785/protein-kinase-c-controls-binding-of-igo-ensa-proteins-to-protein-phosphatase-2a-in-budding-yeast
#9
Vu Thai, Noah Dephoure, Amit Weiss, Jacqueline Ferguson, Ricardo Leitao, Steven P Gygi, Douglas R Kellogg
Protein phosphatase 2A (PP2A) plays important roles in controlling mitosis in all eukaryotic cells. The form of PP2A that controls mitosis is associated with a conserved regulatory subunit that is called B55 in vertebrates and Cdc55 in budding yeast. The activity of this form of PP2A can be inhibited by binding of conserved Igo/ENSA proteins. Although the mechanisms that activate Igo/ENSA to bind to PP2A are well understood, little is known about how they are inactivated. Here, we have analyzed regulation of Igo/ENSA in the context of a checkpoint pathway that links mitotic entry to membrane growth in budding yeast...
January 18, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28100771/janus-kinase-2-jak2-dissociates-hepatosteatosis-from-hepatocellular-carcinoma-in-mice
#10
Sally Yu Shi, Stephanie A Schroer, Cynthia T Luk, Min Jeong Kim, David W Dodington, Lauren Lin, Tharini Sivasubramaniyam, Erica P Cai, Shun-Yan Lu, Kay-Uwe Wagner, Richard P Bazinet, Minna Woo
Hepatocellular carcinoma (HCC) is an end-stage complication of non-alcoholic fatty liver disease (NAFLD). Inflammation plays a critical role in the progression of non-alcoholic fatty liver disease and the development of hepatocellular carcinoma. However, whether steatosis per se promotes liver cancer and the molecular mechanisms that control the progression in this disease spectrum remain largely elusive. The Janus kinase-signal transducers and activators of transcription (JAK-STAT) pathway mediates signal transduction by numerous cytokines that regulate inflammation and may contribute to hepatocarcinogenesis...
January 18, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28100739/action-categories-in-lateral-occipitotemporal-cortex-are-organized-along-sociality-and-transitivity
#11
Moritz F Wurm, Alfonso Caramazza, Angelika Lingnau
: How neural specificity for distinct conceptual knowledge categories arises is central for understanding the organization of semantic memory in the human brain. Although there is a large body of research on the neural processing of distinct object categories, the organization of action categories remains largely unknown. In particular, it is unknown whether different action categories follow a specific topographical organization on the cortical surface analogously to the category-specific organization of object knowledge...
January 18, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28100698/cdc45-induced-loading-of-human-rpa-onto-single-stranded-dna
#12
Anna Szambowska, Ingrid Tessmer, Piotr Prus, Bernhard Schlott, Helmut Pospiech, Frank Grosse
Cell division cycle protein 45 (Cdc45) is an essential component of the eukaryotic replicative DNA helicase. We found that human Cdc45 forms a complex with the single-stranded DNA (ssDNA) binding protein RPA. Moreover, it actively loads RPA onto nascent ssDNA. Pull-down assays and surface plasmon resonance studies revealed that Cdc45-bound RPA complexed with ssDNA in the 8-10 nucleotide binding mode, but dissociated when RPA covered a 30-mer. Real-time analysis of RPA-ssDNA binding demonstrated that Cdc45 catalytically loaded RPA onto ssDNA...
January 18, 2017: Nucleic Acids Research
https://www.readbyqxmd.com/read/28100686/noncanonical-function-of-dgcr8-controls-mesc-exit-from-pluripotency
#13
Daniel Cirera-Salinas, Jian Yu, Maxime Bodak, Richard P Ngondo, Kristina M Herbert, Constance Ciaudo
Mouse embryonic stem cells (mESCs) deficient for DGCR8, a key component of the microprocessor complex, present strong differentiation defects. However, the exact reasons impairing their commitment remain elusive. The analysis of newly generated mutant mESCs revealed that DGCR8 is essential for the exit from the pluripotency state. To dissociate canonical versus noncanonical functions of DGCR8, we complemented the mutant mESCs with a phosphomutant DGCR8, which restored microRNA levels but did not rescue the exit from pluripotency defect...
January 18, 2017: Journal of Cell Biology
https://www.readbyqxmd.com/read/28100654/dissociation-between-sustained-single-neuron-spiking-%C3%AE-rhythmicity-and-transient-%C3%AE-lfp-oscillations-in-primate-motor-cortex
#14
Michael Everett Rule, Carlos E Vargas-Irwin, John P Donoghue, Wilson Truccolo
Determining the relationship between single-neuron spiking and transient (~20 Hz) beta local field potential (β-LFP) oscillations is an important step for understanding the role of these oscillations in motor cortex. We show that while motor cortex firing rates and beta spiking rhythmicity remain sustained during steady-state movement preparation periods, β-LFP oscillations emerge, in contrast, as short transient events. Single-neuron mean firing rates within and outside transient β-LFP events showed no differences, and no consistent correlation was found between the beta oscillations' amplitude and firing rates, as was the case for movement and visual-cue related β-LFP suppression...
January 18, 2017: Journal of Neurophysiology
https://www.readbyqxmd.com/read/28099889/evaluation-of-organosolv-pretreatment-on-the-structural-characteristics-of-lignin-polymers-and-follow-up-enzymatic-hydrolysis-of-the-substrates-from-eucalyptus-wood
#15
Bing Wang, Xiao-Jun Shen, Jia-Long Wen, Lin Xiao, Run-Cang Sun
In the present study, Eucalyptus was subjected to organosolv pretreatment processes with aqueous 2-propanol at 200 to 220°C to obtain lignin with benign characters for its valorization and digestible substrates for bioethanol production. Results showed that different delignification ratios (64.00%-81.26%) and molecular weights (Mw=610-2680g/mol) of lignin fractions were dissociated from various pretreatment conditions, and the glucose yields of all the pretreated substrates significantly increased to 54.65-88...
January 15, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28099529/a-possible-role-of-the-full-length-nascent-protein-in-post-translational-ribosome-recycling
#16
Debasis Das, Dibyendu Samanta, Arpita Bhattacharya, Arunima Basu, Anindita Das, Jaydip Ghosh, Abhijit Chakrabarti, Chanchal Das Gupta
Each cycle of translation initiation in bacterial cell requires free 50S and 30S ribosomal subunits originating from the post-translational dissociation of 70S ribosome from the previous cycle. Literature shows stable dissociation of 70S from model post-termination complexes by the concerted action of Ribosome Recycling Factor (RRF) and Elongation Factor G (EF-G) that interact with the rRNA bridge B2a/B2b joining 50S to 30S. In such experimental models, the role of full-length nascent protein was never considered seriously...
2017: PloS One
https://www.readbyqxmd.com/read/28099028/chemical%C3%A2-insights%C3%A2-into%C3%A2-the%C3%A2-design%C3%A2-and%C3%A2-development%C3%A2-of%C3%A2-face-centered-cubic%C3%A2-ruthenium%C3%A2-catalysts%C3%A2-for%C3%A2-fischer-tropsch%C3%A2-synthesis
#17
Wei-Zhen Li, Jin-Xun Liu, Jun Gu, Wu Zhou, Siyu Yao, Rui Si, Yu Guo, Hai-Yan Su, Chun-Hua Yan, Wei-Xue Li, Ya-Wen Zhang, Ding Ma
Ruthenium is a promising low temperature catalyst for Fischer-Tropsch synthesis (FTS). However, its scarcity and modest specific activity limits its widespread industrialization. We demonstrate here a strategy of tuning the crystal phase of catalysts to expose denser active sites for a higher mass-specific activity. Density functional theory calculations show that upon CO dissociation, there are a number of open facets with modest barrier available on the face-centered cubic (fcc) Ru, but only few step edges with a lower barrier on conventional hexagonal-closest packed (hcp) Ru...
January 18, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28099008/critical-analysis-of-rate-constants-and-turnover-frequency-in-nucleic-acid-templated-reactions-reaching-terminal-velocity
#18
Dalu Chang, Eric Lindberg, Nicolas Winssinger
Nucleic acid-templated reactions have attracted significant attention for nucleic acid sensing and imaging. The level of signal amplification obtained from templated reactions is a function of the template turnover, wherein the template acts as the catalyst. Herein, we report the application of a pyridinium linker that immolates upon photocatalytic reduction with a ru-thenium complex to yield the fastest nucleic acid tem-plated reaction reported to date. We show that the tem-plated reaction turnover is limited by the duplex dissoci-ation kinetics beyond probes longer than a 6-mer and proceeded fastest for a 5-mer PNA probe...
January 18, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28098959/influence-of-electronic-and-molecular-structure-on-the-fragmentation-dynamic-of-even-electron-carbocationic-triangulenes-and-helicenes-in-the-gas-phase
#19
Jakob Felix Hitzenberger, Agnes Uhl, Jürgen Schatz, Thomas Drewello
Stable, long-lived organic cations are directly transferred by electrospray ionization (ESI) from solution into the gas phase where their collision-induced dissociations (CID) are studied by tandem mass spectrometry. Three related types of triphenyl carbenium ions are investigated, in which the meta positions are either substituted by methoxy groups or tertiary nitrogen bridges, including Tetramethoxyphenylacridinium (TMPA(+) ), dimethoxyquinacridinium (DMQA(+) ) and triazatriangulenium (TATA(+) ) cations. These ions are triangular in shape with increasing degrees of planarity...
January 18, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/28098324/ionic-screening-and-dissociation-are-crucial-for-understanding-chemical-self-propulsion-in-polar-solvents
#20
Aidan T Brown, Wilson C K Poon, Christian Holm, Joost de Graaf
Polar solvents like water support the bulk dissociation of themselves and their solutes into ions, and the re-association of these ions into neutral molecules in a dynamic equilibrium, e.g., H2O2 ⇌ H(+) + HO2(-). Using continuum theory, we study the influence of these association-dissociation reactions on the self-propulsion of colloids driven by surface chemical reactions (chemical swimmers). We find that association-dissociation reactions should have a strong influence on swimmers' behaviour, and therefore should be included in future modelling...
January 18, 2017: Soft Matter
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