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Thomas J Pirtle, Troy L Carr, Tanisha Khurana, Grace Meeker
Daphnia magna heartbeat is myogenic-originating within the animal's heart. However, the mechanism for this myogenic automaticity is unknown. The mechanism underlying the automaticity of vertebrate myogenic hearts involves cells (pacemaker cells), which have a distinct set of ion channels that include hyperpolarization activated cyclic nucleotide-gated (HCN) and T-type calcium ion channels. We hypothesized that these ion channels also underlie the automatic myogenic heartbeat of Daphnia magna. The drugs, ZD7288 and mibefradil dihydrochloride, block HCN and T-type calcium ion channels respectively...
April 20, 2018: Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology
Richard Burkett Dewell, Fabrizio Gabbiani
Collision avoidance is critical for survival, including in humans, and many species possess visual neurons exquisitely sensitive to objects approaching on a collision course. Here, we demonstrate that a collision-detecting neuron can detect the spatial coherence of a simulated impending object, thereby carrying out a computation akin to object segmentation critical for proper escape behavior. At the cellular level, object segmentation relies on a precise selection of the spatiotemporal pattern of synaptic inputs by dendritic membrane potential-activated channels...
April 18, 2018: ELife
Saima Saif, Mohammad Saghir Khan
Considering the heavy metal risk to soil microbiota and agro-ecosystems, the study was designed to determine metal toxicity to bacteria and to find metal tolerant bacteria carrying multifarious plant growth promoting activities and to assess their impact on chickpea cultivated in stressed soils. Metal tolerant strain SFP1 recognized as Pseudomonas aeruginosa employing 16S rRNA gene sequence determination showed maximum tolerance to Cr (400 μg/ml) and Ni (800 μg/ml) and produced variable amounts of indole acetic acid, HCN, NH3 , and ACC deaminase and could solubilize insoluble phosphates even under Cr (VI) and Ni stress...
April 17, 2018: Environmental Monitoring and Assessment
Paul Andrew Christensen, Zeinab T A W Mashhadani, Abd Halim Bin Md Ali, Michael A Carroll, Philip A Martin
This paper reports in-situ Fourier Transform Infra Red (FTIR) spectroscopic studies on the non-thermal plasma reaction of isopropyl alcohol in dinitrogen at Macor (a ceramic containing oxides of Al, Mg and Si) and the analogous thermally-driven process. Whilst isopropyl alcohol did not react at the Macor at temperatures up to 600°C, the study of the non-thermal plasma-driven process at the ceramic led to unexpected chemistry hitherto not observed, primarily the reaction of IPA in dinitrogen at short timescales to produce methane, HCN, acetone and "cold" CO at ca...
April 17, 2018: Journal of Physical Chemistry. A
A Cartoni, A R Casavola, P Bolognesi, M C Castrovilli, D Catone, J Chiarinelli, R Richter, L Avaldi
Nitromidazoles are relevant compounds of multidisciplinary interest, and knowledge of their physical-chemical parameters as well as their decomposition under photon irradiation is needed. Here we report an experimental and theoretical study of the mechanisms of VUV photofragmentation of 2- and 4(5)-nitromidazoles, compounds used as radiosensitizers in conjunction with radiotherapy as well as high-energy density materials. Photoelectron-photoion coincidence experiments, measurements of the appearance energies of the most important ionic fragments, density functional theory, and single-point coupled cluster calculations have been used to provide an overall insight into the energetics and structure of the different ionic/neutral products of the fragmentation processes...
April 13, 2018: Journal of Physical Chemistry. A
Beenu Tanwar, Rajni Modgil, Ankit Goyal
The present investigation was aimed to study the effect of detoxification on the nutrients and antinutrients of wild apricot kernel followed by its hypocholesterolemic effect in male Wistar albino rats. The results revealed a non-significant (p > 0.05) effect of detoxification on the proximate composition except total carbohydrates and protein content. However, detoxification led to a significant (p < 0.05) decrease in l-ascorbic acid (76.82%), β-carotene (25.90%), dietary fiber constituents (10.51-28...
April 12, 2018: Food & Function
Bijyalaxmi Athokpam, Sai G Ramesh
We present a study of the abstraction of alkyl hydrogen atoms from the β and α positions of ethanol by the CN radical in solution using the Empirical Valence Bond (EVB) method. We have built separate 2 × 2 EVB models for the Hβ and Hα reactions, where the atom transfer is parameterized using ab initio calculations. The intra- and intermolecular potentials of the reactant and product molecules were modelled with the General AMBER Force Field, with some modifications. We have carried out the dynamics in water and chloroform, which are solvents of contrasting polarity...
April 7, 2018: Journal of Chemical Physics
Saju Balakrishnan, Sergej L Mironov
Hyperventilation is a known feature of Rett syndrome (RTT). However, how hyperventilation is related to other RTT symptoms such as hyperexcitability is unknown. Intense breathing during hyperventilation induces hypocapnia and culminates in respiratory alkalosis. Alkalinization of extracellular milieu can trigger epilepsy in patients who already have neuronal hyperexcitability. By combining patch-clamp electrophysiology and quantitative glutamate imaging, we compared excitability of CA1 neurons of WT and Mecp2 (-/y) mice, and analyzed the biophysical properties of subthreshold membrane channels...
2018: PloS One
K R Anila, Nileena Nayak, Preethi Sara George, K Jayasree
INTRODUCTION: Lesions of the thyroid gland composed of Hurthle cells constitute a wide spectrum of pathological entities ranging from benign hyperplastic nodules with Hurthle cell metaplasia at one end to malignancies like Hurthle cell carcinomas. The cytological distinction of these entities is not only diagnostically challenging but are also critical since they influence treatment decisions. AIM: To critically analyze the cytomorphology of cases of Hurthle cell lesions in FNACs and to characterize cytological features shown to be statistically signific ant in predicting Hurthle cell neoplasm (HCN)...
January 2018: Gulf Journal of Oncology
Marta Mon, Miguel A Rivero-Crespo, Jesús Ferrando-Soria, Alejandro Vidal-Moya, Mercedes Boronat, Antonio Leyva-Pérez, Avelino Corma, Juan C Hernandez-Garrido, Miguel López-Haro, José J Calvino, Giulio Ragazzon, Alberto Credi, Donatella Armentano, Emilio Pardo
The gram-scale synthesis, stabilization and characterization of well-defined ultrasmall subnanometric catalytic clusters on solids represent a challenge. Here, we report the chemical synthesis and X-ray snapshots of Pt20 clusters, homogenously distributed and densely-packaged within the channels of a metal-organic framework. This novel hybrid material catalyzes efficiently, and even most important from an economic and environmental viewpoint, at low temperature (25 to 140 ºC), energetically-costly industrial reactions in the gas phase such as hydrogen cyanide (HCN) production, carbon dioxide (CO2) methanation and alkene hydrogenations...
March 30, 2018: Angewandte Chemie
Konstantin Pokhodnya, Kenneth J Anderson, Svetlana V Kilina, Naveen Kumar Dandu, Philip Boudjouk
We report the detailed computational study of the perchlorinated cyclohexasilane (Si6 Cl12 ) based inverse sandwich compounds (ISCs). It was found that regardless of the donor ligand size and charge, e.g., Cl- and CN- anions or neutral HCN and NCPh nitriles, their coordination to Si6 Cl12 puckered Si6 ring results in its flattening. The NBO and CDA studies of the complexes have shown that coordination occurs due to hybridization of low lying antibonding σ*(Si-Cl) and σ*(Si-Si) unoccupied molecular orbitals (UMOs) of Si6Cl 12 and occupied molecular orbitals (OMOs) of donor molecules (predominantly lone pair related) resulting in donor-to-ring charge transfer accompanied by complex stabilization and ring flattening...
March 28, 2018: Journal of Physical Chemistry. A
Felicitas Becker, Christopher A Reid, Kerstin Hallmann, Han-Shen Tae, A Marie Phillips, Georgeta Teodorescu, Yvonne G Weber, Ailing Kleefuss-Lie, Christian Elger, Edward Perez-Reyes, Steven Petrou, Wolfram S Kunz, Holger Lerche, Snezana Maljevic
Objective: Genetic generalized epilepsy (GGE) encompasses seizure disorders characterized by spike-and-wave discharges (SWD) originating within thalamo-cortical circuits. Hyperpolarization-activated (HCN) and T-type Ca2+ channels are key modulators of rhythmic activity in these brain regions. Here, we screened HCN4 and CACNA1H genes for potentially contributory variants and provide their functional analysis. Methods: Targeted gene sequencing was performed in 20 unrelated familial cases with different subtypes of GGE, and the results confirmed in 230 ethnically matching controls...
September 2017: Epilepsia Open
Paul M Riegelhaupt, Gareth R Tibbs, Peter A Goldstein
The ability of a diverse group of agents to produce general anesthesia has long been an area of intense speculation and investigation. Over the past century, we have seen a paradigm shift from proposing that the anesthetized state arises from nonspecific interaction of anesthetics with the lipid membrane to the recognition that the function of distinct, and identifiable, membrane-embedded proteins is dramatically altered in the presence of intravenous and inhaled agents. Among proteinaceous targets, metabotropic and ionotropic receptors garnered much of the attention over the last 30 years, and it is only relatively recently that voltage-gated ion channels have clearly and rigorously been shown to be important molecular targets...
2018: Methods in Enzymology
Laiche Djouhri, Trevor Smith, Ahmad Ahmeda, Mohammad Alotaibi, Xiechuan Weng
Peripheral neuropathic pain (PNP) associated with partial nerve injury is believed to be driven partly by aberrant spontaneous activity (SA) in both injured and uninjured dorsal root ganglion (DRG) neurons. The underlying ionic mechanisms are not fully understood, but hyperpolarization-activated cyclic nucleotide gated (HCN) channels which underlie the excitatory Ih current have been implicated in SA generation in axotomized A-fiber neurons following L5-spinal nerve ligation/axotomy (SNL/SNA). Here, using a modified model of SNA (mSNA) which involves, in addition to L5-SNA, loose ligation of the L4-spinal nerve with neuroinflammation-inducing chromic-gut, we examined whether HCN channels also contribute to SA in the adjacent L4-neurons...
March 22, 2018: Pain
Junling Wang, Chao Ma, Xiaowei Mu, Wei Cai, Longxiang Liu, Xia Zhou, Weizhao Hu, Yuan Hu
Organic modification of MoSe2 sheets is firstly achieved by Atherton-Todd reaction, aiming at the acquisition of multifunctional MoSe2 hybrid. Simultaneous enhancements in fire safety and mechanical property of thermalplastic polyurethane (TPU) are obtained with the presence of this hybrid. Strong interfacial interactions between the functionalized MoSe2 sheets and TPU can be obtained, making more efficient load transfer from the weak polymer chains to the robust sheets. Besides, more coherent barrier network may be formed in polymer matrix, restraining the diffusion of decomposed fragments and reducing the supply for combustion fuel...
March 8, 2018: Journal of Hazardous Materials
Bushra Uzair, Rehana Kausar, Syeda Asma Bano, Sammer Fatima, Malik Badshah, Ume Habiba, Fehmida Fasim
The use of microbial technologies in agriculture is currently expanding quite rapidly with the identification of new bacterial strains, which are more effective in promoting plant growth. In the present study 18 strains of Pseudomonas were isolated from soil sample of Balochistan coastline. Among isolated Pseudomonas strains four designated as SP19, SP22, PS24, and SP25 exhibited biocontrol activities against phytopathogenic fungi, that is, Rhizopus microsporus, Fusarium oxysporum, Aspergillus niger, Alternaria alternata, and Penicillium digitatum ; PS24 identified as Pseudomonas aeruginosa by 16srRNA gene bank accession number EU081518 was selected on the basis of its antifungal activity to explore its potential as plant growth promotion...
2018: BioMed Research International
Steffan K Kristensen, Espen Z Eikeland, Esben Taarning, Anders T Lindhardt, Troels Skrydstrup
A protocol for the Pd-catalysed cyanation of aryl bromides using near stoichiometric and gaseous hydrogen cyanide is reported for the first time. A two-chamber reactor was adopted for the safe liberation of ex situ generated HCN in a closed environment, which proved highly efficient in the Ni-catalysed hydrocyanation as the test reaction. Subsequently, this setup was exploited for converting a range of aryl and heteroaryl bromides (28 examples) directly into the corresponding benzonitriles in high yields, without the need for cyanide salts...
December 1, 2017: Chemical Science
Sabine Hummert, Susanne Thon, Thomas Eick, Ralf Schmauder, Eckhard Schulz, Klaus Benndorf
Hyperpolarization-activated cyclic nucleotide-modulated (HCN) channels control electrical rhythmicity in specialized brain and heart cells. We quantitatively analysed voltage-dependent activation of homotetrameric HCN2 channels and its modulation by the second messenger cAMP using global fits of hidden Markovian models to complex experimental data. We show that voltage-dependent activation is essentially governed by two separable voltage-dependent steps followed by voltage-independent opening of the pore. According to this model analysis, the binding of cAMP to the channels exerts multiple effects on the voltage-dependent gating: It stabilizes the open pore, reduces the total gating charge from ~8 to ~5, makes an additional closed state outside the activation pathway accessible and strongly accelerates the ON-gating but not the OFF-gating...
March 2018: PLoS Computational Biology
Ji Liu, Qiang Lu, Xiao-Yan Jiang, Bin Hu, Xiao-Lei Zhang, Chang-Qing Dong, Yong-Ping Yang
Coal is a major contributor to the global emission of nitrogen oxides (NOx ). The NOx formation during coal utilization typically derives from the thermal decomposition of N-containing compounds (e.g., pyrrolic groups). NH₃ and HCN are common precursors of NOx from the decomposition of N-containing compounds. The existence of H₂O has significant influences on the pyrrole decomposition and NOx formation. In this study, the effects of H₂O on pyrrole pyrolysis to form NOx precursors HCN and NH₃ are investigated using the density functional theory (DFT) method...
March 21, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Marie-Christine Bacchus-Montabonel
The formation of the building blocks of life and how they could survive under harsh astrophysical environments remains an open question of prebiotic chemistry. Effectively, ion bombardments or intense UV radiation may drive the destruction of prebiotic compounds. The possible role of sulfur in such processes is addressed here for the first time, by comparing directly proton-induced charge transfer for sulfur containing molecules and that for related COMs. The proton collision on mercaptoacetonitrile HSCH2C[triple bond, length as m-dash]N conformers has thus been investigated theoretically in a wide impact energy range modelling various astrophysical environments and compared to related COMs, namely HCN oligomers, in order to exhibit qualitative tendencies...
March 21, 2018: Physical Chemistry Chemical Physics: PCCP
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