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https://www.readbyqxmd.com/read/28102913/autumn-photosynthetic-decline-and-growth-cessation-in-seedlings-of-white-spruce-are-decoupled-under-warming-and-photoperiod-manipulations
#1
Joseph R Stinziano, Danielle A Way
Climate warming is expected to increase the seasonal duration of photosynthetic carbon fixation and tree growth in high latitude forests. However photoperiod, a crucial cue for seasonality, will remain constant, which may constrain tree responses to warming. We investigated the effects of temperature and photoperiod on weekly changes in photosynthetic capacity, leaf biochemistry and growth in seedlings of a boreal evergreen conifer, white spruce (Picea glauca (Moench) Voss). Warming delayed autumn declines in photosynthetic capacity, extending the period when seedlings had high carbon uptake...
January 19, 2017: Plant, Cell & Environment
https://www.readbyqxmd.com/read/28102767/synthesis-stereochemical-characterization-and-antimicrobial-evaluation-of-a-potentially-nonnephrotoxic-3-c-acethydrazide-puromycin-analog
#2
Josh Carter, Blair A Weaver, Maria A Chiacchio, Amy R Messersmith, Will E Lynch, Brent D Feske, Giuseppe Gumina
Puromycin is a peptidyl nucleoside endowed with significant antibiotic and anticancer properties, but also with an unfortunate nephrotoxic character that has hampered its use as a chemotherapeutic agent. Since hydrolysis of puromycin's amide to puromycin aminonucleoside is the first metabolic step leading to nephrotoxicity, we designed a 3'-C-hydrazide analog where the nitrogen and carbon functionality around the amide carbonyl of puromycin are inverted. The title compound, synthesized in 11 steps from D-xylose, cannot be metabolized to the nephrotoxic aminonucleoside...
January 19, 2017: Nucleosides, Nucleotides & Nucleic Acids
https://www.readbyqxmd.com/read/28102677/intramolecular-construction-of-trifluoromethyl-group-by-the-palladium-catalyzed-alkylation-of-2-3-3-trifluoroallylic-carbonates-with-indoles
#3
Taisyun Hanakawa, Kazuki Isa, Shin-Ichi Isobe, Yuji Hoshino, Biao Zhou, Motoi Kawatsura
The palladium-catalyzed alkylation reaction of 2,3,3-trifluoroallylic carbonates with indoles afforded a trifluoromethyl group possessing 3-substituted indole derivatives. The reaction proceeded via attack of the C-3 carbon of the indoles onto the C-2 position of the allylic moiety and intramolecular construction of the trifluoromethyl group by the intramolecular fluorine atom shift from the C-2 position to the C-3 position of the allyl unit.
January 19, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28102672/coupled-cluster-studies-of-ionization-potentials-and-electron-affinities-of-single-walled-carbon-nanotubes
#4
Bo Peng, Niranjan Govind, Edoardo Aprà, Michael Klemm, Jeff R Hammond, Karol Kowalski
In this paper we apply the equation-of-motion coupled cluster (EOM-CC) methods in the studies of the vertical ionization potentials (IPs) and electron affinities (EAs) for a series of single walled carbon nanotubes (SWCNT). The EOM-CC formulations for IPs and EAs employing excitation manifolds spanned by single and double excitations (IP/EA-EOM-CCSD) are used to study the IPs and EAs of the SWCNTs as a func- tion of the nanotube length. Several armchair nanotubes corresponding to C20nH20 models with n = 2 - 6 have been used in benchmark calculations...
January 19, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28102518/quercetin-glucoside-production-by-engineered-escherichia-coli
#5
REVIEW
Tian Xia, Mark A Eiteman
Escherichia coli strains expressing the O-glucosyltransferases UGT73B3 or UGT84B1 were compared for the production of glucosides from quercetin supplied into a defined medium. The formation of quercetin-3-glucoside (Q3G) by UGT73B3 showed a maximum at 33 °C, while the formation of quercetin-7-glucoside by UGT84B1 increased with increasing temperature to 37 °C. The highest concentrations of Q3G were attained by strains having a deletion in the pgi gene-coding phosphoglucose isomerase, which effectively blocked the entry of glucose-6P into the Embden-Meyerhof-Parnas pathway...
January 19, 2017: Applied Biochemistry and Biotechnology
https://www.readbyqxmd.com/read/28102497/regulated-partitioning-of-fixed-carbon-14-c-sodium-na-potassium-k-and-glycine-betaine-determined-salinity-stress-tolerance-of-gamma-irradiated-pigeonpea-cajanus-cajan-l-millsp
#6
Pankaj Kumar, Vasundhara Sharma, Chobhe Kapil Atmaram, Bhupinder Singh
Soil salinity is a major constraint that limits legume productivity. Pigeonpea is a salt sensitive crop. Seed gamma irradiation at a very low dose (2.5 Gy) is known to enhance seedling establishment, plant growth and yield of cereals and other crops. The present study conducted using two genetically diverse varieties of pigeonpea viz., Pusa-991 and Pusa-992 aimed at establishing the role of pre-sowing seed gamma irradiation at 0, 0.0025, 0.005, 0.01, 0.02, 0.05 and 0.1 kGy on plant growth, seed yield and seed quality under salt stress at 0, 80 and 100 mM NaCl (soil solution EC equivalent 1...
January 19, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28102408/bottom-up-synthesis-of-nitrogen-doped-porous-carbon-scaffolds-for-lithium-and-sodium-storage
#7
Hongling Lu, Renpeng Chen, Yi Hu, Xiaoqi Wang, Yanrong Wang, Lianbo Ma, Guoyin Zhu, Tao Chen, Zuoxiu Tie, Zhong Jin, Jie Liu
Here we report an effective bottom-up solution-phase process for the preparation of nitrogen-doped porous carbon scaffolds (NPCSs), which can be employed as high-performance anode materials for both lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs). The as-obtained NPCSs show favorable features for electrochemical energy storage such as high specific surface area, appropriate pore size distribution (3.9 nm in average), large pore volume (1.36 cm(3) g(-1)), nanosheet-like morphology, a certain degree of graphitization, enlarged interlayer distance (0...
January 19, 2017: Nanoscale
https://www.readbyqxmd.com/read/28102407/introducing-tetramethylurea-as-a-new-methylene-precursor-a-microwave-assisted-rucl3-catalyzed-cross-dehydrogenative-coupling-approach-to-bis-indolyl-methanes
#8
Mohit L Deb, Paran J Borpatra, Prakash J Saikia, Pranjal K Baruah
Herein we report a microwave assisted Ru(iii)/TBHP-mediated reaction of indoles with tetramethylurea (TMU) synthesizing symmetrical as well as unsymmetrical bis(indolyl)methanes, where TMU acts as a methylenating agent. This is the first report where TMU is used as a methylene source. Moreover, the synthesis of unsymmetrical bis(indolyl)methanes by using a carbon precursor is also reported herein for the first time. Various substituted indoles are used for the reaction. The reaction is high yielding and takes a much shorter time to accomplish compared to the existing methods...
January 19, 2017: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/28102397/highly-exposed-fe-n4-active-sites-in-porous-poly-iron-phthalocyanine-based-oxygen-reduction-electrocatalyst-with-ultrahigh-performance-for-air-cathode
#9
Ganesan Anandhababu, Syed Comail Abbas, Jiangquan Lv, Kui Ding, Qin Liu, Dickson D Babu, Yiyin Huang, Jiafang Xie, Maoxiang Wu, Yaobing Wang
Progress in the development of efficient electrocatalysts for oxygen reduction reactions is imperative for various energy systems such as metal-air batteries and fuel cells. In this paper, an innovative porous two-dimensional (2D) poly-iron-phthalocyanine (PFe-Pc) based oxygen reduction electrocatalyst created with a simple solid-state chemical reaction without pyrolysis is reported. In this strategy, silicon dioxide nanoparticles play a pivotal role in preserving the Fe-N4 structure during the polymerization process and thereby assist in the development of a porous structure...
January 19, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28102394/markedly-enhanced-visible-light-photocatalytic-h2-generation-over-g-c3n4-nanosheets-decorated-by-robust-nickel-phosphide-ni12p5-cocatalysts
#10
Jiuqing Wen, Jun Xie, Rongchen Shen, Xin Li, XingYi Luo, Hongdan Zhang, Aiping Zhang, Guican Bi
In the present work, nickel phosphide (Ni12P5) modified graphitic carbon nitride (g-C3N4) nanosheets were synthesized by a simple grinding method. The structural characterization clearly proved that Ni12P5 nanoparticles were well loaded on the surface of g-C3N4 nanosheets. The photocatalytic activity of the composites was tested by catalyzing the reduction of water to hydrogen under visible light irradiation. The results demonstrate that Ni12P5 is an efficient co-catalyst for photocatalytic H2 production of g-C3N4 nanosheets...
January 19, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28102382/three-component-carboarylation-of-unactivated-imines-with-arynes-and-carbon-nucleophiles
#11
Jing-Kun Xu, Sheng-Jun Li, Hai-Yang Wang, Wen-Cong Xu, Shi-Kai Tian
With 2-(trimethylsilyl)aryl triflates as aryne precursors, an unprecedented three-component carboarylation reaction of unactivated imines with arynes and carbon nucleophiles has been developed to access a variety of functionalized tertiary amines under transition metal-free conditions. Suitable carbon nucleophiles include chloroform, acetonitrile, and methyl propiolate.
January 19, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28102373/unprecedented-photochemical-rearrangement-of-an-open-cage-c60-derivative
#12
Tsukasa Futagoishi, Michihisa Murata, Atsushi Wakamiya, Yasujiro Murata
Upon irradiation of a sulfoxide C60 derivative with a 17-membered-ring opening, rearrangement of the carbon framework took place to give an unprecedented lactone C60 derivative with a 14-membered-ring opening, whose structure was unambiguously determined by single crystal X-ray analysis. This reaction is completely different from that of the previously reported sulfoxide C60 and C70 derivatives with a 13-membered-ring opening.
January 19, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28102329/leads-in-arctic-pack-ice-enable-early-phytoplankton-blooms-below-snow-covered-sea-ice
#13
Philipp Assmy, Mar Fernández-Méndez, Pedro Duarte, Amelie Meyer, Achim Randelhoff, Christopher J Mundy, Lasse M Olsen, Hanna M Kauko, Allison Bailey, Melissa Chierici, Lana Cohen, Anthony P Doulgeris, Jens K Ehn, Agneta Fransson, Sebastian Gerland, Haakon Hop, Stephen R Hudson, Nick Hughes, Polona Itkin, Geir Johnsen, Jennifer A King, Boris P Koch, Zoe Koenig, Slawomir Kwasniewski, Samuel R Laney, Marcel Nicolaus, Alexey K Pavlov, Christopher M Polashenski, Christine Provost, Anja Rösel, Marthe Sandbu, Gunnar Spreen, Lars H Smedsrud, Arild Sundfjord, Torbjørn Taskjelle, Agnieszka Tatarek, Jozef Wiktor, Penelope M Wagner, Anette Wold, Harald Steen, Mats A Granskog
The Arctic icescape is rapidly transforming from a thicker multiyear ice cover to a thinner and largely seasonal first-year ice cover with significant consequences for Arctic primary production. One critical challenge is to understand how productivity will change within the next decades. Recent studies have reported extensive phytoplankton blooms beneath ponded sea ice during summer, indicating that satellite-based Arctic annual primary production estimates may be significantly underestimated. Here we present a unique time-series of a phytoplankton spring bloom observed beneath snow-covered Arctic pack ice...
January 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28102293/ocean-warming-and-acidification-synergistically-increase-coral-mortality
#14
F Prada, E Caroselli, S Mengoli, L Brizi, P Fantazzini, B Capaccioni, L Pasquini, K E Fabricius, Z Dubinsky, G Falini, S Goffredo
Organisms that accumulate calcium carbonate structures are particularly vulnerable to ocean warming (OW) and ocean acidification (OA), potentially reducing the socioeconomic benefits of ecosystems reliant on these taxa. Since rising atmospheric CO2 is responsible for global warming and increasing ocean acidity, to correctly predict how OW and OA will affect marine organisms, their possible interactive effects must be assessed. Here we investigate, in the field, the combined temperature (range: 16-26 °C) and acidification (range: pHTS 8...
January 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28102274/base-the-social-cost-of-carbon-on-the-science
#15
EDITORIAL
(no author information available yet)
No abstract text is available yet for this article.
January 18, 2017: Nature
https://www.readbyqxmd.com/read/28102229/the-neurosteroidogenic-enzyme-5%C3%AE-reductase-mediates-psychotic-like-complications-of-sleep-deprivation
#16
Roberto Frau, Valentina Bini, Alessio Soggiu, Simona Scheggi, Alessandra Pardu, Silvia Fanni, Paola Roncada, Monica Puligheddu, Francesco Marrosu, Donatella Caruso, Paola Devoto, Marco Bortolato
Acute sleep deprivation (SD) can trigger or exacerbate psychosis- and mania-related symptoms; the neurobiological basis of these complications, however, remains elusive. Given the extensive involvement of neuroactive steroids in psychopathology, we hypothesized that the behavioral complications of SD may be contributed by 5α-reductase (5αR), the rate-limiting enzyme in the conversion of progesterone into the neurosteroid allopregnanolone. We first tested whether rats exposed to SD may exhibit brain-regional alterations in 5αR isoenzymes and neuroactive steroid levels; then, we assessed whether the behavioral and neuroendocrine alterations induced by SD may be differentially modulated by the administration of the 5αR inhibitor finasteride, as well as progesterone and allopregnanolone...
January 19, 2017: Neuropsychopharmacology: Official Publication of the American College of Neuropsychopharmacology
https://www.readbyqxmd.com/read/28102224/optimality-and-sub-optimality-in-a-bacterial-growth-law
#17
Benjamin D Towbin, Yael Korem, Anat Bren, Shany Doron, Rotem Sorek, Uri Alon
Organisms adjust their gene expression to improve fitness in diverse environments. But finding the optimal expression in each environment presents a challenge. We ask how good cells are at finding such optima by studying the control of carbon catabolism genes in Escherichia coli. Bacteria show a growth law: growth rate on different carbon sources declines linearly with the steady-state expression of carbon catabolic genes. We experimentally modulate gene expression to ask if this growth law always maximizes growth rate, as has been suggested by theory...
January 19, 2017: Nature Communications
https://www.readbyqxmd.com/read/28102079/medium-sized-cyclic-ethers-via-stevens-1-2-shift-of-mixed-monothioacetal-derived-sulfonium-ylides-application-to-formal-synthesis-of-laurencin
#18
Rongrong Lin, Liya Cao, F G West
A novel approach to medium-sized cyclic ethers was devised using a Stevens [1,2]-shift of a sulfonium ylide derived from a readily accessible six-membered mixed-monothioacetal precursor. The concise and efficient transformation offers a surprising degree of chirality transfer with observed retention of stereochemical configuration on the anomeric migrating carbon and has been applied as the key step in an enantioselective formal synthesis of (+)-laurencin.
January 19, 2017: Organic Letters
https://www.readbyqxmd.com/read/28102074/growth-of-a-large-area-free-standing-highly-conductive-and-fully-foldable-silver-film-with-inverted-pyramids-for-wearable-electronics-applications
#19
Xiao Yu, Zihua Li, Yong Liu, Wen-Xia Zhao, Ruimei Xu, Donghai Wang, Hui Shen
A promising new concept is the application of flexible and foldable conductive film or paper for wearable electronics, in which silver nanowires, carbon nanotubes and graphene are primarily used as conductive materials. However, their insufficient nanostructure contacts lead to poor electrical conductivity and mechanical fracture. Here, we demonstrate a simple and innovative strategy for fabricating a free-standing silver film with inverted pyramids by replicating pyramids on a textured silicon wafer under a hydrothermal reaction...
January 19, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28102018/microwave-assisted-rapid-synthesis-of-self-assembled-t-nb2o5-nanowires-for-high-energy-hybrid-supercapacitors
#20
Huiling Yang, Henghui Xu, Libin Wang, Lei Zhang, Yunhui Huang, Xianluo Hu
Recently ion-intercalation hybrid supercapacitors with high energy density at high power density have been widely investigated to meet the ever-increasing practical applications. Here a unique hybrid supercapacitor is designed and fabricated using self-assembled orthorhombic-phase niobium oxide@carbon (T-Nb2O5@C) nanowires as an anode and commercially available activated carbon as a cathode. The 3D-interconnected T-Nb2O5@C nanowires have been synthesized via a highly efficient microwave-solvothermal method combined with subsequent thermal treatment...
January 19, 2017: Chemistry: a European Journal
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