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https://www.readbyqxmd.com/read/28817652/metabolomics-reveals-an-entanglement-of-fasting-leptin-concentrations-with-fatty-acid-oxidation-and-gluconeogenesis-in-healthy-children
#1
Franca Fabiana Kirchberg, Stephanie Brandt, Anja Moß, Wolfgang Peissner, Wolfgang Koenig, Dietrich Rothenbacher, Hermann Brenner, Berthold Koletzko, Christian Hellmuth, Martin Wabitsch
BACKGROUND: Leptin and adiponectin communicate with organ systems in order to regulate energetic and metabolic homeostasis. Their different points of action have been well characterized; however, no study has investigated their interrelationship with the metabolism at the molecular level in vivo. OBJECTIVE: To examine the associations of leptin and adiponectin with the metabolic profile reflecting the intercellular and interorgan communication as well as activated metabolic pathways...
2017: PloS One
https://www.readbyqxmd.com/read/28817292/theoretical-analysis-of-the-retro-diels-alder-reactivity-of-oxanorbornadiene-thiol-and-amine-adducts
#2
Jason S Fell, Steven A Lopez, Cody J Higginson, M G Finn, K N Houk
Additions of amines or thiols to 7-oxanorbornadienes promote retro-[4 + 2] reactions to yield furans. Substitution at the bridgehead position also greatly influences the stability of the oxanorbornene adducts. Activation and reaction energies were computed with the M06-2X density functional, the origins of amine and thiol promoted fragmentation, and how substituent effects control fragmentation rates and reaction energetics are reported.
August 17, 2017: Organic Letters
https://www.readbyqxmd.com/read/28817281/linking-solution-structures-and-energetics-thorium-nitrate-complexes
#3
Suntharalingam Skanthakumar, Geng Bang Jin, Jian Lin, Valérie Vallet, Lynda Soderholm
Seeking predictive insights into how metal-ion speciation impacts solution chemistry as well as the composition and structure of solid-precipitates, thorium correlations, with both solvent and other solute ions, were quantitatively probed in a series of acidic, nitrate/perchlorate solutions held at constant ionic strength. Difference pair-distribution functions (dPDF), obtained from high-energy x-ray scattering (HEXS) data, provide unprecedented structural information on the number of Th ligating ions in solution and how they change with increasing nitrate concentration...
August 17, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28816459/observation-and-characterization-of-ch3ch2-mh-ch2-2-mh2-ch2-ch-mh3-and-ch3-c%C3%A2-mh3-produced-by-reactions-of-group-5-metal-atoms-with-ethane
#4
Han-Gook Cho, Lester Andrews
The primary products in reactions of laser-ablated group 5 metal atoms with ethane have been identified in argon matrix IR spectra and characterized via DFT computations. The 2nd and 3rd row transition-metals produced insertion, metallacyclopropane, vinyl trihydrido, and anionic ethylidyne complexes (CH3CH2-MH, (CH2)2-MH2, CH2=CH-MH3, and CH3C≡MH3-) while the 1st row transition-metal yielded only the insertion and metallacyclopropane products. The energetically higher ethylidenes and neutral ethylidynes (CH3CH=MH2 and CH3C≐MH3) were not detected...
August 17, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28816457/a-coupled-cluster-investigation-of-sno-radical-isomers-and-their-reactions-with-hydrogen-atom-insight-into-structures-conformers-barriers-and-energetics
#5
Manoj Kumar, Joseph S Francisco
High-level coupled cluster theory with single and double excitation, and including a perturbative triples correction (CCSD(T)) method and a series of Dunning's augmented correlation consistent basis sets, aug-cc-pVXZ (X=D, T, Q and 5) was applied to examine the conformational landscape of SNO radical system. The basis set has an important effect on the relative stability of SNO radical isomers, and the NSO radical is the most stable member of SNO radical family. This is in contrast to previous density functional theory prediction suggesting SNO radical is the most stable isomer...
August 17, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28816323/indirect-dynamics-in-sn2-n-insight-into-the-influence-of-central-atoms
#6
Xu Liu, Chenyang Zhao, Li Yang, Jiaxu Zhang, Rui Sun
Central atoms have a significant influence on the reaction kinetics and dynamics of nucleophilic substitution (SN2). Herein, atomistic dynamics of a prototype SN2@N reaction F(-) + NH2Cl is uncovered employing direct dynamics simulations that show strikingly distinct features from those determined for a SN2@C congener F(-) + CH3Cl. Indirect scattering is found to prevail, which proceeds predominantly through a hydrogen-bonded F(-)-HNHCl complex in the reactant entrance channel. This unexpected finding of a pronounced contribution of indirect reaction dynamics, even at a high collision energy, is in strong contrast to a general evolution from indirect to direct dynamics with enhanced energy that characterizes SN2@C...
August 17, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28816245/ram-pressure-feeding-of-supermassive-black-holes
#7
Bianca M Poggianti, Yara L Jaffé, Alessia Moretti, Marco Gullieuszik, Mario Radovich, Stephanie Tonnesen, Jacopo Fritz, Daniela Bettoni, Benedetta Vulcani, Giovanni Fasano, Callum Bellhouse, George Hau, Alessandro Omizzolo
When a supermassive black hole at the centre of a galaxy accretes matter, it gives rise to a highly energetic phenomenon: an active galactic nucleus. Numerous physical processes have been proposed to account for the funnelling of gas towards the galactic centre to feed the black hole. There are also several physical processes that can remove gas from a galaxy, one of which is ram-pressure stripping by the hot gas that fills the space between galaxies in galaxy clusters. Here we report that six out of a sample of seven 'jellyfish' galaxies-galaxies with long 'tentacles' of material that extend for dozens of kiloparsecs beyond the galactic disks-host an active nucleus, and two of them also have galactic-scale ionization cones...
August 16, 2017: Nature
https://www.readbyqxmd.com/read/28815951/physics-based-all-atom-modeling-of-rna-energetics-and-structure
#8
REVIEW
Louis G Smith, Jianbo Zhao, David H Mathews, Douglas H Turner
The database of RNA sequences is exploding, but knowledge of energetics, structures, and dynamics lags behind. All-atom computational methods, such as molecular dynamics, hold promise for closing this gap. New algorithms and faster computers have accelerated progress in improving the reliability and accuracy of predictions. Currently, the methods can facilitate refinement of experimentally determined nuclear magnetic resonance and x-ray structures, but are 'unreliable' for predictions based only on sequence...
September 2017: Wiley Interdisciplinary Reviews. RNA
https://www.readbyqxmd.com/read/28815872/a-multimethod-computational-simulation-approach-for-investigating-mitochondrial-dynamics-and-dysfunction-in-degenerative-aging
#9
Timothy E Hoffman, Katherine J Barnett, Lyle Wallis, William H Hanneman
Research in biogerontology has largely focused on the complex relationship between mitochondrial dysfunction and biological aging. In particular, the mitochondrial free radical theory of aging (MFRTA) has been well accepted. However, this theory has been challenged by recent studies showing minimal increases in reactive oxygen species (ROS) as not entirely deleterious in nature, and even beneficial under the appropriate cellular circumstances. To assess these significant and nonintuitive observations in the context of a functional system, we have taken an in silico approach to expand the focus of the MFRTA by including other key mitochondrial stress response pathways, as they have been observed in the nematode Caenorhabditis elegans...
August 16, 2017: Aging Cell
https://www.readbyqxmd.com/read/28815815/synthesis-optical-properties-and-dna-interaction-of-new-diquats-based-on-triazolopyridines-and-triazoloquinolines
#10
Pedro J Llabres-Campaner, Lluís Guijarro, Claudia Giarratano, Rafael Ballesteros-Garrido, Ramón J Zaragozá, M José Aurell, Enrique García-España, Rafael Ballesteros, Belén Abarca
New diquat derivatives based on [1,2,3]triazolo[1,5-a]pyridine and [1,2,3]triazolo[1,5-a]quinoline have been synthesized in excellent yields. To evaluate the effect of the alkyl bridge length, ethane and propane dibromo alkane substrates were used for their synthesis. Theoretical calculations predicted a very small energetic barrier between the two possible enantiomers P (Ra ) and M (Sa ), which makes them very difficult to resolve. Thermal denaturation studies, UV/Visible spectroscopy, and fluorescence titrations with ct-DNA evidenced the intercalation of the quinoline derivatives in DNA...
August 16, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28815648/direct-uptake-of-hco3-in-the-marine-angiosperm-posidonia-oceanica-l-delile-driven-by-a-plasma-membrane-h-economy
#11
Lourdes Rubio, Delia García, María J García-Sánchez, F Xavier Niell, Hubert H Felle, José A Fernández
Seagrasses access HCO3(-) for photosynthesis by two mechanisms, apoplastic carbonic anhydrase-mediated dehydration of HCO3(-) to CO2 , and direct HCO3(-) uptake. Here we have studied plasma membrane energization and the mechanism for HCO3(-) import in Posidonia oceanica. Classical electrophysiology and ion selective microelectrodes were used to measure the membrane potential, cytosolic pH and the cytosolic concentrations of Na(+) and Cl(-) upon the addition of HCO3(-) . The photosynthetic response to HCO3(-) and to inhibitors was also measured...
August 16, 2017: Plant, Cell & Environment
https://www.readbyqxmd.com/read/28815462/a-new-erice-report-considering-the-safety-of-medicines-in-the-21st-century
#12
Ivor Ralph Edwards
Pharmacovogilance policy, methods and practice require transformation at all levels to create an integrated, comprehensive, continuously improving system, fulfilling the broader remit of overall healthcare vigilance. In pursuit of this vision, energetic measures, including active engagement with patients, are needed to reduce our ignorance about many aspects of patients' experience of medical therapies and their outcomes, including the benefits, but especially the extensive harm known to be caused by medical interventions...
August 17, 2017: Drug Safety: An International Journal of Medical Toxicology and Drug Experience
https://www.readbyqxmd.com/read/28814762/down-regulation-of-pdk4-is-critical-for-the-switch-of-carbohydrate-catabolism-during-syncytialization-of-human-placental-trophoblasts
#13
Xiaohui Liu, Rujuan Zuo, Yirong Bao, Xiaoxian Qu, Kang Sun, Hao Ying
Pyruvate dehydrogenase kinase (PDK) is known as a gatekeeper directing the carbon flux into glycolysis via inhibition of the pyruvate dehydrogenase complex. During syncytialization of placental trophoblasts, both ATP production and oxygen consumption are increased to meet enhanced energetic demands by syntiotrophoblasts. We hypothesized that down-regulation of PDK expression may play a central role in the switch from glycolysis to oxidative phosphorylation (OXPHOS) during syncytialization. By using primary human trophoblasts, we demonstrated that PDK4 was the dominating PDK isoform in human cytotrophoblasts, and its abundance was substantially decreased upon syncytialization, which was accompanied by decreases in lactate production and increases in ATP production...
August 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28814714/evaluation-of-thermodynamics-formation-energetics-and-electronic-properties-of-vacancy-defects-in-cazro3
#14
Syed Muhammad Alay-E-Abbas, Safdar Nazir, Stefaan Cottenier, Ali Shaukat
Using first-principles total energy calculations we have evaluated the thermodynamics and the electronic properties of intrinsic vacancy defects in orthorhombic CaZrO3. Charge density calculations and the atoms-in-molecules concept are used to elucidate the changes in electronic properties of CaZrO3 upon the introduction of vacancy defects. We explore the chemical stability and defect formation energies of charge-neutral as well as of charged intrinsic vacancies under various synthesis conditions and also present full and partial Schottky reaction energies...
August 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28814658/sperm-competition-games-when-males-invest-in-paternal-care
#15
Gustavo S Requena, Suzanne H Alonzo
Sperm competition games investigate how males partition limited resources between pre- and post-copulatory competition. Although extensive research has explored how various aspects of mating systems affect this allocation, male allocation between mating, fertilization and parental effort has not previously been considered. Yet, paternal care can be energetically expensive and males are generally predicted to adjust their parental effort in response to expected paternity. Here, we incorporate parental effort into sperm competition games, particularly exploring how the relationship between paternal care and offspring survival affects sperm competition and the relationship between paternity and paternal care...
August 16, 2017: Proceedings. Biological Sciences
https://www.readbyqxmd.com/read/28814630/inverted-region-electron-transfer-as-a-mechanism-for-enhancing-photosynthetic-solar-energy-conversion-efficiency
#16
Hiroki Makita, Gary Hastings
In all photosynthetic organisms, light energy is used to drive electrons from a donor chlorophyll species via a series of acceptors across a biological membrane. These light-induced electron-transfer processes display a remarkably high quantum efficiency, indicating a near-complete inhibition of unproductive charge recombination reactions. It has been suggested that unproductive charge recombination could be inhibited if the reaction occurs in the so-called inverted region. However, inverted-region electron transfer has never been demonstrated in any native photosynthetic system...
August 16, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28814001/design-of-an-energy-efficient-transfemoral-prosthesis-using-lockable-parallel-springs-and-electrical-energy-transfer
#17
Francois Heremans, Renaud Ronsse
Over the last decade, active lower-limb prostheses demonstrated their ability to restore a normal gait for transfemoral amputees by supplying the required positive energy balance [1]. However, the added-value of such devices is significantly impacted by their limited energetic autonomy preventing their full appropriation by the patients. There is thus a strong incentive to reduce the overall power consumption of active prostheses. Addressing this need requires to revisit the electromechanical design. For both the ankle and the knee, the present paper demonstrates that both the use of a lockable parallel spring and the transfer of electrical energy between joints can significantly improve the energetic performance for overground walking...
July 2017: IEEE ... International Conference on Rehabilitation Robotics: [proceedings]
https://www.readbyqxmd.com/read/28813975/a-lightweight-robotic-ankle-prosthesis-with-non-backdrivable-cam-based-transmission
#18
Tommaso Lenzi, Marco Cempini, Jeremy Newkirk, Levi J Hargrove, Todd A Kuiken
Below-knee level amputation significantly impacts the ability of an individual to ambulate. Transtibial amputees are typically prescribed energetically passive ankle-foot prostheses that behave as a spring or controlled damper, and therefore cannot fully replace the function of the missing limb. More recently, fully-powered devices have been proposed to more closely match the power generation ability of intact limbs. However, these fully-powered devices are significantly heavier than passive devices, thus increasing the stress on the socket-residual limb interface...
July 2017: IEEE ... International Conference on Rehabilitation Robotics: [proceedings]
https://www.readbyqxmd.com/read/28812983/a-microfluidic-platform-for-modeling-metastatic-cancer-cell-matrix-invasion
#19
Laura Blaha, Chentian Zhang, Mario Cabodi, Joyce Y Wong
Invasion of the extracellular matrix is a critical step in the colonization of metastatic tumors. The invasion process is thought to be driven by both chemokine signaling and interactions between invading cancer cells and physical components of the metastatic niche, including endothelial cells that line capillary walls and serve as a barrier to both diffusion and invasion of the underlying tissue. Transwell chambers, a tool for generating artificial chemokine gradients to induce cell migration, have facilitated recent work to investigate the chemokine contributions to matrix invasion...
August 16, 2017: Biofabrication
https://www.readbyqxmd.com/read/28812878/nanomechanical-imaging-of-the-diffusion-of-fullerene-into-conjugated-polymer
#20
Dong Wang, Ken Nakajima, Feng Liu, Shaowei Shi, Thomas P Russell
The large Young's modulus difference between chemically modified fullerene (PCBM) and a conjugated polymer was used to nanomechanically map the diffusion of PCBM into PTB7, a high efficiency low band gap conjugated polymer. The sharp tip in nanomechanical atomic force microscopy (AFM) ensures a high-resolution nanomechanical characterization of the diffusion front, with the intrinsic benefits of revealing the mechanical properties of the mixtures. Localized structure changes induced by diffusion were investigated by grazing incidence x-ray diffraction methods...
August 16, 2017: ACS Nano
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