ALBERT

Description: The effect of metal ions (M n+  = Na + , K + , Mg 2+ , Ca 2+ , Zn 2+ and hydrated Mg 2+ ions) and water molecules on the tautomerism of adenine induced by single intramolecular proton transfer (SPT) have been investigated theoretically. Calculated results show that the single proton transfer process in adenine base is favored and even becomes thermodynamically spontaneous because of the presence of M n+ interacting at the N 3 position of adenine. On the contrary, if M n+ coordinated to N 7 site, the single proton transfer process will become unfavorable than that in the neutral system. The effects of metal ions on the SPT of adenine base are more pronounced if Lewis acidity of metal ion is increased. Water plays a more important role than metal ions during the SPT process. It is found that water can act not only as a solvent but also as a mediator which gives and accepts protons to promote SPT, playing a bridge role. As a result, inclusion of a water molecule drastically reduces the energy barrier for the SPT. Moreover, two water molecules can yield larger assisting effect on the SPTs compared with one water molecule. We can conclude that the tautomerism of DNA adenine base can be modulated by the metal ions and water molecules. Copyright © 2015 John Wiley & Sons, Ltd. Single intramolecular proton transfer (SPT) is favored when M n+ interacting at the N 3 position of adenine. SPT becomes unfavorable if M n+ coordinated with N 7 atom of adenine. Water can act as a mediator to assist the SPT in adenine base.

Description: We investigate PM 2.5 data reliability in five major Chinese cities: Beijing, Shanghai, Guangzhou, Chengdu and Shenyang by cross-validating data from the US diplomatic posts and the nearby Ministry of Environmental Protection sites based on three years' data from January 2013. The investigation focuses on the consistency in air quality assessment derived from the two data sources. It consists of studying (i) the occurrence length and percentage of different PM 2.5 concentration ranges; (ii) the air quality assessment for each city; and (iii) the winter-heating effects in Beijing and Shenyang. Our analysis indicates that the two data sources produced highly consistent air quality assessment in the five cities. This is encouraging as it would inject a much needed confidence on the air pollution measurements from China. We also provide air quality assessments on the severity and trends of the fine particulate matter pollution in the five cities. The assessments are produced by statistically constructing the standard monthly meteorological conditions for each city, which are designed to minimize the effects of confounding factors due to yearly variations of some important meteorological variables. Our studies show that Beijing and Chengdu had the worst air quality, while Guangzhou and Shanghai faired the best among the five cities. Most of the five cities had their PM 2.5 concentration decreased significantly in the last two years. By linking the air quality with the amount of energy consumed, our study suggests that the geographical configuration is a significant factor in a city's air quality management and economic development.

Description: [1]  Based on field investigations, aerial-photos morphological analysis, topographic profiling, and optically stimulated luminescence (OSL) dating of alluvial surfaces, we estimate vertical components of the slip rate along the South Heli Shan thrust Fault, which lies on the northern margin of the Hexi corridor and the northeastern edge of the Tibetan Plateau. The fault consists of three segments with scarp heights ranging from less than 1 m to more than 14 m. OSL dating indicates that most of the alluvial fans cut by fault scarps formed during the transition from last glacial stage to present interglacial stage from ~19 ka to ~9 ka along southern Heli Shan, from ~27 ka to ~22 ka, along its northern margin. In addition, remnants of older alluvial fan have been abandoned after ~67 ka. Scarp heights increase from west to east and reach a maximum of more than 14 m near the eastern end. Using three approaches we calculate late Quaternary slip rates for each of three fault segments along the southern margin, and the fault on the northern flank. These approaches yield maximum vertical slip rates from 0.18 to 0.2 mm/a for western segment, 0.3 to 0.43 mm/a for central segment, 0.36 to 0.53 mm/a for eastern segment, and 0.21 mm/a for the Wutongjing fault, which lies on the north side of the Heli Shan. For a range of likely fault dips, these correspond to 0.1-0.2 mm/a of average horizontal shortening for western segment, and increase to 0.4-0.5 mm/a across the eastern segment of southern Heli Shan fault. Combining the height of eastern parts of the Heli Shan (Daqing Peak) above the Hei He (a major river that incised the western end of the range) and the vertical component of the slip rate of the eastern segment, we suggest that the Heli Shan was uplifted by motion on the south Heili Shan fault beginning sometime between 1 and 4 Ma, most likely since ~2 Ma. This age suggests that the Tibetan Plateau continues to grow northeastward across the Hexi Corridor.

Description: Two new iridoid esters, named valerjatadoids A and B ( 1 and 2 , resp.), together with three known iridoid esters, jatamanin O ( 3 ), jatamanvaltrate P ( 4 ), and jatamanvaltrate Q ( 5 ), have been isolated from the root and rhizome of Valeriana jatamansi Jones . The structures of the two new compounds were elucidated by spectroscopic analyses, including 2D-NMR techniques.

Description: Ribosomal protein S6 (rpS6) has long been regarded as one of the primary r-proteins that functions in the early stage of 40S subunit assembly, but its actual role is still obscure. The correct forming of 18S rRNA is a key step in the nuclear synthesis of 40S subunit. In this study, we demonstrate that rpS6 participates in the processing of 30S pre-rRNA to 18S rRNA only when its C-terminal five serines are phosphorylated, however, the process of entering the nucleus and then targeting the nucleolus does not dependent its phosphorylation. Remarkably, we also find that the aggregation of rpS6 at the nucleolus correlates to the phasing of cell cycle, beginning to concentrate in the nucleolus at later S phase and disaggregate at M phase. This article is protected by copyright. All rights reserved

Description: Many experimental studies have found that flavonoids including luteolin can inhibit the activities of matrix metalloproteinases (MMPs), but the related theoretical studies are rather lacking. In this paper, we perform PM6 quantum chemistry calculations together with modeling of ligand-water exchange reactions to investigate the mechanisms of interaction between luteolin and catalytic zinc ion in MMPs. The calculations show that the electron transfer from the luteolin molecule to the catalytic zinc ion in MMPs occurs when the catalytic zinc ion coordinates with the O atoms of substituent groups at various positions of A, B, and C rings of luteolin molecule. It is found that the more the number of the electron transfer from one coordinating O atom of substituent groups of luteolin molecule to the catalytic zinc ion, the stronger the coordinating ability between them. We further find that comparing with the O atoms of hydroxy groups at 5-, 7-, 3′-, and 4′-positions of luteolin molecule, the coordinating ability for the O atom of carbonyl group at its 4-position with the catalytic zinc ion is the strongest, which indicates that when luteolin inhibits MMPs activity, the catalytic zinc ion should coordinate with the carbonyl group at 4-position of luteolin molecule, rather than the hydroxy groups at its other positions, in agreement with the relevant experimental results reported in previous literature. This paper may be helpful for designing the new MMPs inhibitors having higher biological activities by carrying out the structural modifications of luteolin molecule. Copyright © 2012 John Wiley & Sons, Ltd. PM6 calculations show that electron transfer from luteolin to catalytic Zn 2+ in MMPs occurs when the catalytic Zn 2+ coordinates with the O atoms of substituent groups of luteolin. The more the number of electron transfer from one coordinating O atom of substituent groups of luteolin to catalytic Zn 2+ , the stronger the coordinating ability between them. It is found that the coordinating ability for O atom of carbonyl group at 4-position of luteolin with catalytic Zn 2+ is the strongest.

Description: Measurements of ambient formaldehyde (HCHO), related gases and particulate matter were carried out from the SUNY Albany mobile platform at the Queens College site in New York City (NYC) from 15 July to 3 August 2009. Ambient HCHO was measured using a quantum cascade laser (QCL) trace gas detector. HCHO concentrations ranged from 0.4 to 7.5 ppb with a mean value of 2.2 ± 1.1 ppb. Daily HCHO peaks were nearly always found between 1100 EST (Eastern Standard Time) and noontime throughout the sampling period. HCHO correlated strongly with NOx and black carbon during the traffic rush hours, but around noontime HCHO correlated much better with total oxidants (Ox = O3 + NO2). Using the diurnal pattern of HCHO/BC ratios, we estimated that 70% of HCHO present between 1200 EST to 1500 EST was produced by photochemical reactions. Sources of photochemically produced HCHO were calculated using measured concentrations of hydrocarbons, their reaction kinetics with OH radicals, and HCHO yields. These calculations indicated that isoprene oxidation was the dominant source of HCHO for this period at this site, responsible for 44%, followed by methane (25%) and propene (18%). To assess the impact of HCHO as a radical source, the HOx production rates from HCHO, HONO, O3 photolysis, and alkenes +O3 were calculated as well. Daily averaged HOx production rates from HONO, HCHO, O3 photolysis and alkenes +O3 were 8.6 × 106, 2.3 × 106, 1.7 × 106, 2.1 × 105 molecules cm−3 s−1, respectively, contributing 67, 18, 13 and 2% to the overall daily HOx radical budget from these precursors.

Description: [1]  This study provides estimates of the human contribution to the observed widespread intensification of precipitation extremes. We consider the annual maxima of daily (RX1day) and five-day consecutive (RX5day) precipitation amounts over the Northern Hemisphere land area for 1951-2005 and compare observed changes with expected responses to external forcings as simulated by multiple coupled climate models participating in CMIP5. The effect of anthropogenic forcings can be detected in extreme precipitation observations, both individually and when simultaneously estimating anthropogenic and naturally forced changes. The effect of natural forcings is not detectable. We estimate that human influence has intensified annual maximum one-day precipitation in sampled Northern Hemisphere locations by 3.3% [1.1% to 5.8%, 〉90% confidence interval] on average. This corresponds to an average intensification in RX1day of 5.2% [1.3%, 9.3%] per degree increase in observed global mean surface temperature consistent with the Clausius-Clapeyron relationship.

Description: Three new neolignans, (7 S ,8 S ,7′ E )-4,9-dihydroxy-3,7,3′,9′-tetramethoxy-8,4′-oxyneolign-7′-ene ( 1 ), (7 R ,8 S ,7′ E )-4, 9-dihydroxy-3,7,3′,9′-tetramethoxy-8,4′-oxyneolign-7′-ene ( 2 ), (7 S ,8 S ,7′ E )-5, 9-dihydroxy-3,7,3′,5′,9′-pentamethoxy-8,4′-oxyneolign-7′-ene ( 3 ), and one new phenylpropanoid, threo -5-hydroxy-3,7-dimethoxyphenylpropane-8,9-diol ( 4 ), were isolated from the leaves and stems of Toona ciliata var. pubescens. Their structures were determined on the basis of spectroscopic analysis, especially 2D-NMR, HR-ESI-MS, and CD data. The antiproliferative activities of these compounds against four tumor cell lines (A549, Colo 205, QGY-7703, and LOVO) were also evaluated by MTT (=(3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2 H -tetrazolium bromide) method.