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https://www.readbyqxmd.com/read/28231498/bone-specific-poly-ethylene-sodium-phosphate-bearing-biodegradable-nanoparticles
#1
Yuya Hirano, Yasuhiko Iwasaki
Chemotherapy is the most reliable treatment for osteoporosis and osseous metastases. To facilitate better drug delivery for bone treatments, a novel preparation of polymeric nanoparticles with high affinity to bone has been prepared. Two-step synthesis of cholesteryl-functionalized poly(ethylene sodium phosphate) (Ch-PEPn·Na) was performed via ring-opening polymerization of cyclic phosphoesters and the demethylation. The molecular weight of Ch-PEPn·Na could be well controlled by changing the ratio of cholesterol and cyclic phosphoesters...
February 16, 2017: Colloids and Surfaces. B, Biointerfaces
https://www.readbyqxmd.com/read/28230965/fluorine-functionalized-graphene-quantum-dots-as-inhibitor-against-hiapp-amyloid-aggregation
#2
Maryam Yousaf, Huan Huang, Ping Li, Chen Wang, Yanlian Yang
Fibrillar deposits of the human islet amyloid polypeptide (hIAPP) is considered as a root of Type II diabetes mellitus. Fluorinated graphene quantum dots (FGQDs) are new carbon nanomaterials with unique physicochemical properties containing highly electronegative F atoms. Herein we report a single step synthesis method of FGQDs with an inhibitory effect on aggregation and cytotoxicity of hIAPP in vitro. Highly fluorescent and water dispersible FGQDs, less than 3 nm in size were synthesized by the microwave-assisted hydrothermal method...
February 23, 2017: ACS Chemical Neuroscience
https://www.readbyqxmd.com/read/28230125/seven-temperate-terrestrial-planets-around-the-nearby-ultracool-dwarf-star-trappist-1
#3
Michaël Gillon, Amaury H M J Triaud, Brice-Olivier Demory, Emmanuël Jehin, Eric Agol, Katherine M Deck, Susan M Lederer, Julien de Wit, Artem Burdanov, James G Ingalls, Emeline Bolmont, Jeremy Leconte, Sean N Raymond, Franck Selsis, Martin Turbet, Khalid Barkaoui, Adam Burgasser, Matthew R Burleigh, Sean J Carey, Aleksander Chaushev, Chris M Copperwheat, Laetitia Delrez, Catarina S Fernandes, Daniel L Holdsworth, Enrico J Kotze, Valérie Van Grootel, Yaseen Almleaky, Zouhair Benkhaldoun, Pierre Magain, Didier Queloz
One aim of modern astronomy is to detect temperate, Earth-like exoplanets that are well suited for atmospheric characterization. Recently, three Earth-sized planets were detected that transit (that is, pass in front of) a star with a mass just eight per cent that of the Sun, located 12 parsecs away. The transiting configuration of these planets, combined with the Jupiter-like size of their host star-named TRAPPIST-1-makes possible in-depth studies of their atmospheric properties with present-day and future astronomical facilities...
February 22, 2017: Nature
https://www.readbyqxmd.com/read/28228777/natural-mineral-waters-chemical-characteristics-and-health-effects
#4
REVIEW
Sara Quattrini, Barbara Pampaloni, Maria Luisa Brandi
Water contributes significantly to health and a daily intake of 1.5 to 2 liters of water should be guaranteed, because a good hydration is essential to maintain the body water equilibrium, although needs may vary among people. However, worldwide population is far from the Recommended Allowance for water intake. Among the waters for human uses, there are 'waters (treated or not), intended for drinking, used for the food and beverages preparation or for other domestic purposes' and natural mineral waters, that are 'originated from an aquifer or underground reservoir, spring from one or more natural or bore sources and have specific hygienic features and, eventually, healthy properties'...
September 2016: Clinical Cases in Mineral and Bone Metabolism
https://www.readbyqxmd.com/read/28228031/partition-dft-on-the-water-dimer
#5
Sara Gómez, Jonathan Nafziger, Albeiro Restrepo, Adam Wasserman
As is well known, the ground-state symmetry group of the water dimer switches from its equilibrium Cs-character to C2h-character as the distance between the two oxygen atoms of the dimer decreases below RO-O∼2.5 Å. For a range of RO-O between 1 and 5 Å, and for both symmetries, we apply Partition Density Functional Theory (PDFT) to find the unique monomer densities that sum to the correct dimer densities while minimizing the sum of the monomer energies. We calculate the work involved in deforming the isolated monomer densities and find that it is slightly larger for the Cs geometry for all RO-O...
February 21, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28226249/micro-milling-of-spent-granular-activated-carbon-for-its-possible-reuse-as-an-adsorbent-remaining-capacity-and-characteristics
#6
Long Pan, Yuichi Takagi, Yoshihiko Matsui, Taku Matsushita, Nobutaka Shirasaki
We milled granular activated carbons (GACs) that had been used for 0-9 years in water treatment plants and produced carbon particles with different sizes and ages: powdered activated carbons (PAC, median diameter 12-42 μm), superfine PAC (SPAC, 0.9-3.5 μm), and submicron-sized SPAC (SSPAC, 220-290 nm). The fact that SPAC produced from 1-year-old GAC and SSPAC from 2-year-old GAC removed 2-methylisoborneol (MIB) from water with an efficiency similar to that of virgin PAC after a carbon contact time of 30 min suggests that spent GAC could be reused for water treatment after being milled...
February 14, 2017: Water Research
https://www.readbyqxmd.com/read/28225102/stability-of-reverse-micelles-in-rare-earth-separation-a-chemical-model-based-on-a-molecular-approach
#7
Yushu Chen, Magali Duvail, Philippe Guilbaud, Jean-François Dufrêche
Molecular complexes formed in the organic phase during solvent extraction may self-assemble as reverse micelles, and therefore induce a supramolecular organization of this phase. In most of the cases, water molecules play an essential role in the organization of this non polar medium. The aim of this work is to investigate the speciation of the aggregates formed in the organic phase during solvent extraction, and especially to assess their stability as a function of the number of water molecules included in their polar core...
February 22, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28222865/simulated-oil-release-from-oil-contaminated-marine-sediment-in-the-bohai-sea-china
#8
Lingling Yuan, Longxi Han, Wenjie Bo, Hua Chen, Wenshen Gao, Bo Chen
There is a high degree of heavy oil partitioning into marine sediments when an oil spill occurs. Contaminated sediment, as an endogenous pollution source, can re-pollute overlying water slowly. In this study, a static oil release process and its effects in marine sediment was investigated through a series of experiments with reproductive heavy oil-contaminated marine sediment. The oil release process was accurately simulated with a Lagergren first-order equation and reached equilibration after 48h. The fitted curve for equilibrium concentration (C0) and first-order rate constant (k1) for sediment pollution levels exhibited a first-order log relationship...
February 17, 2017: Marine Pollution Bulletin
https://www.readbyqxmd.com/read/28220128/effect-of-leaf-water-potential-on-internal-humidity-and-co2-dissolution-reverse-transpiration-and-improved-water-use-efficiency-under-negative-pressure
#9
Timo Vesala, Sanna Sevanto, Tiia Grönholm, Yann Salmon, Eero Nikinmaa, Pertti Hari, Teemu Hölttä
The pull of water from the soil to the leaves causes water in the transpiration stream to be under negative pressure decreasing the water potential below zero. The osmotic concentration also contributes to the decrease in leaf water potential but with much lesser extent. Thus, the surface tension force is approximately balanced by a force induced by negative water potential resulting in concavely curved water-air interfaces in leaves. The lowered water potential causes a reduction in the equilibrium water vapor pressure in internal (sub-stomatal/intercellular) cavities in relation to that over water with the potential of zero, i...
2017: Frontiers in Plant Science
https://www.readbyqxmd.com/read/28214776/the-metabolic-impact-of-extracellular-nitrite-on-aerobic-metabolism-of-paracoccus-denitrificans
#10
K R Hartop, M J Sullivan, G Giannopoulos, A J Gates, P L Bond, Z Yuan, T A Clarke, G Rowley, D J Richardson
Nitrite, in equilibrium with free nitrous acid (FNA), can inhibit both aerobic and anaerobic growth of microbial communities through bactericidal activities that have considerable potential for control of microbial growth in a range of water systems. There has been much focus on the effect of nitrite/FNA on anaerobic metabolism and so, to enhance understanding of the metabolic impact of nitrite/FNA on aerobic metabolism, a study was undertaken with a model denitrifying bacterium Paracoccus denitrificans PD1222...
February 7, 2017: Water Research
https://www.readbyqxmd.com/read/28214583/remediation-of-fluoride-from-drinking-water-using-magnetic-iron-oxide-coated-hydrotalcite-chitosan-composite
#11
Kalimuthu Pandi, Soodamani Periyasamy, Natrayasamy Viswanathan
The present study was performed to examine the probability of magnetic iron oxide fabricated hydrotalcite/chitosan (Fe3O4@HTCS) composite for the removal of excess fluoride content from drinking water. The developed Fe3O4@HTCS composite not only demonstrate the good separation ability but also display an extreme enhanced defluoridation capacity (DC) when compared to other base components and composite. The DCs of Fe3O4@HTCS composite, Fe3O4@HT composite, Fe3O4, HT and CS was found to be 5032, 3041, 1050, 1030 and 52 mgF(-)/kg respectively...
February 15, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28213708/removal-mechanisms-for-extremely-high-level-fluoroquinolone-antibiotics-in-pharmaceutical-wastewater-treatment-plants
#12
Xinyan Guo, Zheng Yan, Yi Zhang, Xiangji Kong, Deyang Kong, Zhengjun Shan, Na Wang
Pharmaceutical wastewater treatment plants (PWWTPs) receive industrial effluents from the plant that contain extremely high levels of antibiotics and are regarded as one of the major sources of antibiotics in the environment. Two PWWTPs have been selected in Zhejiang Province, China, to assess the removal mechanisms of fluoroquinolone antibiotics (FQs). PWWTP A uses activated sludge with biocarriers in a moving bed biofilm reactor in anoxic and aerobic units, and PWWTP B uses biological units under anaerobic, aerobic, and anoxic conditions...
February 17, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28208083/biodegradation-testing-of-chemicals-with-high-henry-s-constants-separating-mass-and-effective-concentration-reveals-higher-rate-constants
#13
Heidi Birch, Henrik R Andersen, Mike Comber, Philipp Mayer
During simulation-type biodegradation tests, volatile chemicals will continuously partition between water phase and headspace. This study addressed how (1) this partitioning affects test results and (2) can be accounted for by combining equilibrium partition and dynamic biodegradation models. An aqueous mixture of 9 (semi)volatile chemicals was first generated using passive dosing and then diluted with environmental surface water producing concentrations in the ng/L to μg/L range. After incubation for 2 h to 4 weeks, automated Headspace Solid Phase Microextraction (HS-SPME) was applied directly on the test systems to measure substrate depletion by biodegradation relatively to abiotic controls...
February 3, 2017: Chemosphere
https://www.readbyqxmd.com/read/28207546/effects-of-postexercise-ice-water-and-room-temperature-water-immersion-on-the-sensory-organization-of-balance-control-and-lower-limb-proprioception-in-amateur-rugby-players-a-randomized-controlled-trial
#14
Gary C C Chow, Timothy T T Yam, Joanne W Y Chung, Shirley S M Fong
BACKGROUND: This single-blinded, three-armed randomized controlled trial aimed to compare the effects of postexercise ice-water immersion (IWI), room-temperature water immersion (RWI), and no water immersion on the balance performance and knee joint proprioception of amateur rugby players. METHODS: Fifty-three eligible amateur rugby players (mean age ± standard deviation: 21.6 ± 2.9 years) were randomly assigned to the IWI group (5.3 °C), RWI group (25...
February 2017: Medicine (Baltimore)
https://www.readbyqxmd.com/read/28204943/effect-of-methyl-groups-on-conformational-properties-of-small-ionized-comb-like-polyelectrolytes-at-the-atomic-level
#15
Hongxia Zhao, Jiaping Liu, Qianping Ran, Yong Yang, Xin Shu
Comb-like polycarboxylate ether (PCE) molecules with different content of methyl groups substituted on backbone and different location of methyl groups substituted on the side chains, respectively, were designed and were studied in explicit salt solutions by all-atom molecular dynamics simulations. Methyl groups substituted on the backbone of PCE have a great effect on the conformation of PCE. Stiffness of charged backbone was not only affected by the rotational freedom but also the electrostatic repulsion between the charged COO(-) groups...
March 2017: Journal of Molecular Modeling
https://www.readbyqxmd.com/read/28202131/how-irreversible-adsorption-affects-interfacial-properties-of-polymers
#16
REVIEW
Simone Napolitano, Michele Sferrazza
Growing experimental evidence shows that the behavior of polymer chains confined at the nanoscale level strongly depends on the degree of adsorption correlated to the number density of monomers pinned onto the supporting substrate. In this contribution, after introducing the physics behind the mechanisms of irreversible adsorption, we review recent experimental observations on how adsorption affects properties of polymer melts confined in 1D, focusing on those related to the thermal glass transition, maximum water uptake, viscosity and crystallization...
February 9, 2017: Advances in Colloid and Interface Science
https://www.readbyqxmd.com/read/28201887/a-corresponding-states-analysis-of-the-liquid-vapor-equilibrium-properties-of-common-water-models
#17
Malte Fugel, Volker C Weiss
Many atomistic potential models have been proposed to reproduce the properties of real water and to capture as many of its anomalies as possible. The large number of different models indicates that this task is by no means an easy one. Some models are reasonably successful for various properties, while others are designed to account for only a very few specific features of water accurately. Among the most popular models are SPC/E, TIP4P, TIP4P/2005, TIP4P/Ice, and TIP5P-E. Here, we report the equilibrium properties of the liquid-vapor coexistence, such as the densities of the liquid phase and the vapor phase, the interfacial tension between them, and the vapor pressure at saturation...
February 14, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28193468/using-the-fundamentals-of-adsorption-to-understand-peak-distortion-due-to-strong-solvent-effect-in-hydrophilic-interaction-chromatography
#18
Fabrice Gritti, Jyotsna Sehajpal, Jacob Fairchild
The peak distortion observed in hydrophilic interaction chromatography (HILIC) may be caused by the sample diluent to mobile phase mismatch. The United States Pharmacopeia (USP) method for organic impurities in cetirizine HCl tablets calls for such a mismatch, having a higher concentration of strong solvent in the sample diluent than in the mobile phase. A significant peak deformation is reported for cetirizine (a second-generation antihistamine) when it is purified on a Ethylene Bridged Hybrid (BEH) HILIC column (4...
February 6, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28187260/mp4-study-of-the-anharmonic-coupling-of-the-shared-proton-stretching-vibration-of-the-protonated-water-dimer-in-equilibrium-and-transition-states
#19
George Pitsevich, Alexander Malevich, Ekaterina Kozlovskaya, Ekaterina Mahnach, Iryna Doroshenko, Valeriy Pogorelov, Lars G M Pettersson, Valdas Sablinskas, Vytautas Balevicius
The structure and harmonic- and anharmonic IR spectra of the protonated water dimer (PWD) were calculated in C1, C2 and CS symmetry at the MP4/acc-pVTZ level of theory. We found that structure and IR spectra are practically identical in C2 and C1 symmetry demonstrating that an equilibrium С1 configuration of the PWD is not realized. Anharmonic coupling of the shared proton stretching vibration with all other modes in the PWD in C2 and CS symmetry was the focus of this investigation. For this purpose 28 two-dimensional potential energy surfaces (2D PES) were built at the MP4/acc-pVTZ level of theory and the corresponding vibrational Schrödinger equations were solved using the DVR method...
February 10, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28186752/deconstructing-free-energies-in-the-law-of-matching-water-affinities
#20
Yu Shi, Thomas L Beck
The law of matching water affinities (LMWA) is explored in classical molecular dynamics simulations of several alkali halide ion pairs spanning the size range from small kosmotropes to large chaotropes. The ion-ion potentials of mean force (PMFs) are computed using three methods: the local molecular field theory (LMFT), the weighted histogram analysis method (WHAM), and integration of the average force (IAF). All three methods produce the same total PMF for a given ion pair. In addition, LMFT-based partitioning into van der Waals and local and far-field electrostatic free energies, and assessment of the enthalpic, entropic, and ion-water components, yield insights into the origins of the observed free energy profiles in water...
February 10, 2017: Journal of Physical Chemistry. B
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