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https://www.readbyqxmd.com/read/28531116/photoreactions-of-endohedral-metallofullerene-with-siliranes-electronic-properties-of-carbosilylated-lu%C3%A2-n-ih-c80
#1
Masahiro Kako, Kazuya Minami, Taiki Kuroiwa, Shinpei Fukazawa, Yuki Arikawa, Michio Yamada, Yutaka Maeda, Qiao-Zhi Li, Shigeru Nagase, Takeshi Akasaka
Photochemical carbosilylation of Lu₃N@Ih-C80 was performed using siliranes (silacyclopropanes) to afford the corresponding [5,6]- and [6,6]-adducts. Electrochemical studies indicated that the redox potentials of the carbosilylated derivatives were shifted cathodically in comparison with those of the [5,6]-pyrrolidino adducts. The electronic effect of the silirane addends on Lu₃N@Ih-C80 was verified on the basis of density functional theory calculations.
May 20, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28529962/picosecond-sulfur-k-edge-x-ray-absorption-spectroscopy-with-applications-to-excited-state-proton-transfer
#2
Benjamin E Van Kuiken, Matthew R Ross, Matthew L Strader, Amy A Cordones, Hana Cho, Jae Hyuk Lee, Robert W Schoenlein, Munira Khalil
Picosecond X-ray absorption (XA) spectroscopy at the S K-edge (∼2.4 keV) is demonstrated and used to monitor excited state dynamics in a small organosulfur molecule (2-Thiopyridone, 2TP) following optical excitation. Multiple studies have reported that the thione (2TP) is converted into the thiol (2-Mercaptopyridine, 2MP) following photoexcitation. However, the timescale and photochemical pathway of this reaction remain uncertain. In this work, time-resolved XA spectroscopy at the S K-edge is used to monitor the formation and decay of two transient species following 400 nm excitation of 2TP dissolved in acetonitrile...
July 2017: Structural Dynamics (Melville, N.Y.)
https://www.readbyqxmd.com/read/28529515/changes-in-leaf-anatomical-traits-enhanced-photosynthetic-activity-of-soybean-grown-in-hydroponics-with-plant-growth-promoting-microorganisms
#3
Roberta Paradiso, Carmen Arena, Veronica De Micco, Maria Giordano, Giovanna Aronne, Stefania De Pascale
The use of hydroponic systems for cultivation in controlled climatic conditions and the selection of suitable genotypes for the specific environment help improving crop growth and yield. We hypothesized that plant performance in hydroponics could be further maximized by exploiting the action of plant growth-promoting organisms (PGPMs). However, the effects of PGPMs on plant physiology have been scarcely investigated in hydroponics. Within a series of experiments aimed to identify the best protocol for hydroponic cultivation of soybean [Glycine max (L...
2017: Frontiers in Plant Science
https://www.readbyqxmd.com/read/28528145/uv-induced-electron-transfer-between-triethylamine-and-5-bromo-2-deoxyuridine-a-puzzle-concerning-the-photochemical-debromination-of-labeled-dna
#4
Paweł Wityk, Magdalena Zdrowowicz, Justyna Wiczk, Janusz Rak
5-Bromo-2'-deoxyuridine (BrdU) photosensitizes DNA to strand break formation. However, this type of photodamage is completely quenched by the presence of triethylamine (TEA) which originates from RP-HPLC purification commonly employed by oligonucleotide providers. While the presence of TEA in oligonucleotide samples does not interfere with PCR or other molecular biology applications, the mechanism of photochemical reaction proceeding in the labeled DNA is dramatically changed due to the photoinduced electron transfer (PET) between the photoexcited BrdU and the ground state TEA...
May 11, 2017: Journal of Pharmaceutical and Biomedical Analysis
https://www.readbyqxmd.com/read/28527429/coexistence-of-light-driven-na-and-h-transport-in-a-microbial-rhodopsin-from-nonlabens-dokdonensis
#5
Hongshen Zhao, Baofu Ma, Liangliang Ji, Longjie Li, Huanhuan Wang, Deliang Chen
Ion pumping microbial rhodopsins are photochemically active membrane proteins, converting light energy into ion-motive-force for ATP synthesis. Nonlabens dokdonensis rhodopsin 2 (NdR2), was recently identified as a light-driven Na(+) pump. However, few functional studies on NdR2 have been conducted to elucidate its mechanism of ion transport. By reconstituting NdR2 into liposomes, we proved that NdR2 functions as a light-driven Na(+)/H(+) pump. As Na(+) concentration increased, the dominant H(+) pump activity switched to the Na(+) pump activity at neutral pH...
May 10, 2017: Journal of Photochemistry and Photobiology. B, Biology
https://www.readbyqxmd.com/read/28527000/fluorescent-coelenteramide-containing-protein-as-a-color-bioindicator-for-low-dose-radiation-effects
#6
Alena S Petrova, Anna A Lukonina, Gennadii A Badun, Nadezhda S Kudryasheva
The study addresses the application of fluorescent coelenteramide-containing proteins as color bioindicators for radiotoxicity evaluation. Biological effects of chronic low-dose radiation are under investigation. Tritiated water (200 MBq/L) was used as a model source of low-intensive ionizing radiation of beta type. 'Discharged obelin,' product of bioluminescent reaction of marine coelenterate Obelia longissimi, was used as a representative of the coelenteramide-containing proteins. Coelenteramide, fluorophore of discharged obelin, is a photochemically active molecule; it produces fluorescence forms of different color...
May 19, 2017: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/28526981/rubisco-mutants-of-chlamydomonas-reinhardtii-display-divergent-photosynthetic-parameters-and-lipid-allocation
#7
M G Esquível, A R Matos, J Marques Silva
Photosynthesis and lipid allocation were investigated in Rubisco small subunit mutants of the microalga Chlamydomonas reinhardtii. Comparative analyses were undertaken with cells grown photoheterotrophically under sulphur-replete or sulphur-depleted conditions. The Y67A Rubisco mutant, which has previously demonstrated a pronounced reduction in Rubisco levels and higher hydrogen production rates than the wild type, also shows the following divergences in photosynthetic phenotype and lipid allocation: (i) low Fv/Fm (maximum photochemical efficiency), (ii) low effective quantum yield of photosystem II (ΦPSII), (iii) low effectiveness at protection against high light intensities, (iv) a higher level of total lipids per pigment and (v) changes in the relative proportions of different fatty acids, with a marked decrease in unsaturated fatty acids (FAs)...
May 19, 2017: Applied Microbiology and Biotechnology
https://www.readbyqxmd.com/read/28526116/allelopathic-interactions-between-the-macroalga-hizikia-fusiformis-harvey-and-the-harmful-blooms-forming-dinoflagellate-karenia-mikimotoi
#8
Zengling Ma, Mingjiang Wu, Lidong Lin, Ronald W Thring, Hengguo Yu, Xu Zhang, Min Zhao
The effects of algal blooms on seaweeds have been rarely studied, although harmful algal blooms (HABs) are now normally regarded as worldwide incidents. In the present study, the effects of dense Karenia mikimotoi cells on the growth and photosynthesis of Hizikia fusiformis, a common and commercially cultivated macroalga in coastal waters of the East China Sea (ECS), were studied to understand the possible consequences when the mariculture encountered a dense harmful algal bloom. Furthermore, the counteraction of the latter on the growth and photosynthetic activities of K...
May 2017: Harmful Algae
https://www.readbyqxmd.com/read/28522461/solar-thermochemical-splitting-of-water-to-generate-hydrogen
#9
C N R Rao, Sunita Dey
Solar photochemical means of splitting water (artificial photosynthesis) to generate hydrogen is emerging as a viable process. The solar thermochemical route also promises to be an attractive means of achieving this objective. In this paper we present different types of thermochemical cycles that one can use for the purpose. These include the low-temperature multistep process as well as the high-temperature two-step process. It is noteworthy that the multistep process based on the Mn(II)/Mn(III) oxide system can be carried out at 700 °C or 750 °C...
May 18, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28518072/in-vivo-investigation-of-antimicrobial-blue-light-therapy-for-multidrug-resistant-acinetobacter-baumannii-burn-infections-using-bioluminescence-imaging
#10
Yucheng Wang, Olivia D Harrington, Ying Wang, Clinton K Murray, Michael R Hamblin, Tianhong Dai
Burn infections continue to be an important cause of morbidity and mortality. The increasing emergence of multidrug-resistant (MDR) bacteria has led to the frequent failure of traditional antibiotic treatments. Alternative therapeutics are urgently needed to tackle MDR bacteria. An innovative non-antibiotic approach, antimicrobial blue light (aBL), has shown promising effectiveness against MDR infections. The mechanism of action of aBL is not yet well understood. It is commonly hypothesized that naturally occurring endogenous photosensitizing chromophores in bacteria (e...
April 28, 2017: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/28513677/regular-and-red-shifted-fluorescence-of-the-donor-acceptor-compound-5-1h-pyrrole-1-yl-thiophenecarbonitrile-tcn-is-efficiently-quenched-by-internal-modes-of-thiophene
#11
Mercedes V Bohnwagner, Irene Burghardt, Andreas Dreuw
The photochemical properties of thiophene analogs of N-pyrrolobenzonitrile (PBN), notably the two isomers 5-(1H-pyrrole-1-yl)thiophene-2-carbonitrile (2-TCN) and 5-(1H-pyrrole-1-yl)thiophene-3-carbonitrile (3-TCN) have been investigated. The aim of this study is to reveal whether the donor-acceptor compound TCN shows a fluorescence behavior similar to other benzonitrile derivatives like PBN and N,N-dimethylaminobenzonitrile (DMABN). For this purpose high-level ab initio methods have been employed comprising approximate coupled cluster (CC2) methods, the algebraic-diagramatic construction scheme for the polarization propagator (ADC(2) and ADC(3)) as well as time-dependent density functional theory (TDDFT)...
May 17, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28513637/the-synergy-between-atomically-dispersed-pd-and-cerium-oxide-for-enhanced-catalytic-properties
#12
Xue Wang, Jiayu Chen, Jianxin Zeng, Qiuxiang Wang, Zejun Li, Ruixuan Qin, Changzheng Wu, Zhaoxiong Xie, Lansun Zheng
We report a photochemical synthesis of Pd/CeO2 catalysts with atomically dispersed Pd. Compared to atomically dispersed Pd/CeO2 with a cubic CeO2 support (Pd/CeO2-CP), atomically dispersed Pd/CeO2 with a truncated octahedral CeO2 support (Pd/CeO2-TOP) exhibited higher activity and selectivity, owing to the synergy between Pd atoms and the (111) surface of CeO2. When compared to Pd/CeO2 with Pd clusters and nanoparticles via chemical reduction, Pd/CeO2-TOP showed excellent activity with an enhancement factor of 324 in CO oxidation, as well as an activity enhancement by a factor of 344 in selective oxidation of benzyl alcohol...
May 17, 2017: Nanoscale
https://www.readbyqxmd.com/read/28513156/quantum-chemical-investigation-on-photochemical-reactions-of-nonanoic-acids-at-air-water-interface
#13
Pin Xiao, Qian Wang, Wei-Hai Fang, Ganglong Cui
Photoinduced chemical reactions of organic compounds at the marine boundary layer have recently attracted significant experimental attention because this kind of photoreactions have been proposed to have substantial impact on local new particle formation (NPF) and their photoproducts could be as a source of secondary organic aerosols (SOA). In this work, we have employed first-principles density functional theory (DFT) method combined with cluster models to systematically explore photochemical reaction pathways of nonanoic acids (NAs) to form volatile saturated and unsaturated C9 and C8 aldehydes at air-water interfaces...
May 17, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28513152/a-molecular-mechanism-for-non-photochemical-quenching-in-cyanobacteria
#14
Yue Lu, Haijun Liu, Rafael Saer, Veronica Lynn Li, Hao Zhang, Liuqing Shi, Carrie Goodson, Michael L Gross, Robert E Blankenship
The cyanobacterial Orange Carotenoid Protein (OCP) protects photosynthetic cyanobacteria from photodamage by dissipating excess excitation energy collected by phycobilisomes (PBS) as heat. Dissociation of the PBS-OCP complex in vivo is facilitated by another protein known as the Fluorescence Recovery Protein (FRP), which primarily exists as a dimeric complex. We used various mass spectrometry(MS)-based techniques to investigate the molecular mechanism of this FRP-mediated process. FRP in the dimeric state (dFRP) retains its high affinity to the C-terminal domain (CTD) of OCP in the red state (OCP(r))...
May 17, 2017: Biochemistry
https://www.readbyqxmd.com/read/28510489/urban-heat-island-uhi-influence-on-secondary-pollutant-formation-at-a-tropical-humid-environment
#15
Gsnvksn Swamy, S M Shiva Nagendra, Uwe Shlink
The combined action of urbanization (change in land use) and increase in vehicular emissions intensify the urban heat island (UHI) effect in many cities in the developed countries. The urban warming (UHI) enhances heat stress related diseases and ozone (O3) levels due to a photochemical reaction. Even though UHI intensity depends on wind speed, wind direction and solar flux, the thermodynamic properties of surface materials can accelerate the temperature profiles at the local scale. This mechanism modifies the atmospheric boundary layer (ABL) structure and mixing height in urban regions...
May 16, 2017: Journal of the Air & Waste Management Association
https://www.readbyqxmd.com/read/28510443/light-controlled-switching-of-a-non-photoresponsive-molecular-shuttle
#16
Liu-Pan Yang, Fei Jia, Jie-Shun Cui, Song-Bo Lu, Wei Jiang
In this research, we report that the acid/base-switchable molecular shuttle without any photoresponsive group can be controlled photochemically by coupling to the indazole-based photoacid via an intermolecular proton-transfer process. The photocontrolled shuttling of the wheel can be conveniently monitored by following the fluorescent evolution during the photoirradiation.
May 16, 2017: Organic Letters
https://www.readbyqxmd.com/read/28510434/mechanistic-description-of-photochemical-oligomer-formation-from-aqueous-pyruvic-acid
#17
Rebecca J Rapf, Russell J Perkins, Barry K Carpenter, Veronica Vaida
The aqueous phase photochemistry of pyruvic acid, an important oxidation product of isoprene, is known to generate larger oligomeric species that may contribute to the formation of secondary organic aerosol in the atmosphere. Using high resolution negative mode electrospray ionization mass spectrometry, the aqueous photochemistry of dilute solutions of pyruvic acid (10, 1, and 0.5 mM) under anaerobic conditions was investigated. Even at the lowest concentration, covalently-bonded dimers and trimers of pyruvic acid were observed as photochemical products...
May 16, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28510424/structure-dependent-binding-of-hnrnp-a1-to-telomere-rna
#18
Xiao Liu, Takumi Ishizuka, Hong-Liang Bao, Kei Wada, Yuuma Takada, Keisuke Iida, Kazuo Nagasawa, Danzhou Yang, Yan Xu
Telomeric repeat-containing RNA is a new non-coding RNA molecule that performs various bio-functions. Heterogeneous nuclear ribonucleoprotein (hnRNP) A1 is an RNA-binding protein involved in the telomere maintenance machinery. To date, little is known about how hnRNPA1 binds to telomeric RNA. In this study, we investigated the binding affinity and recognition mechanism of telomere RNA with the RNA recognition motif (RRM) of hnRNPA1. Using the photochemical crosslinking method, we showed that the telomere RNA G-quadruplex with loops is important in the interaction of telomere RNA with hnRNPA1...
May 16, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28510419/sunlight-promotes-fast-release-of-hazardous-cadmium-from-widely-used-commercial-cadmium-pigment
#19
Huiting Liu, Han Gao, Mingce Long, Heyun Fu, Pedro J J Alvarez, Qilin Li, Shourong Zheng, Xiaolei Qu, Dongqiang Zhu
Cadmium pigments are widely used in the polymer and ceramic industry. Their potential environmental risk is under debate, being the major barrier for appropriate regulation. We show that 83.0 ± 0.2 % of hazardous cadmium ion (Cd2+) was released from the commercial cadmium sulfoselenide pigment (i.e., cadmium red) in aqueous suspension within 24 h under simulated sunlit conditions. This photo-dissolution process also generated sub-20 nm pigment nanoparticles. Cd2+ release is attributed to the reactions between photogenerated holes and the pigment lattices...
May 16, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28510190/chilling-susceptibility-in-mungbean-varieties-is-associated-with-their-differentially-expressed-genes
#20
Li-Ru Chen, Chia-Yun Ko, William R Folk, Tsai-Yun Lin
BACKGROUND: Mungbean (Vigna radiata L. Wilczek) is an economically important legume of high nutritional value, however, its cultivation is limited by susceptibility to chilling. Varieties NM94 and VC1973A, with differential susceptibility to stress, serve as good materials for uncovering how they differ in chilling tolerance. This study aimed to identify the ultrastructural, physiological and molecular changes to provide new insights on the differential susceptibility to chilling between varieties VC1973A and NM94...
December 2017: Botanical Studies (Taipei, Taiwan)
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