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https://www.readbyqxmd.com/read/28813504/effect-of-co2-induced-seawater-acidification-on-growth-photosynthesis-and-inorganic-carbon-acquisition-of-the-harmful-bloom-forming-marine-microalga-karenia-mikimotoi
#1
Shunxin Hu, Bin Zhou, You Wang, Ying Wang, Xinxin Zhang, Yan Zhao, Xinyu Zhao, Xuexi Tang
Karenia mikimotoi is a widespread, toxic and non-calcifying dinoflagellate, which can release and produce ichthyotoxins and hemolytic toxins affecting the food web within the area of its bloom. Shifts in the physiological characteristics of K. mikimotoi due to CO2-induced seawater acidification could alter the occurrence, severity and impacts of harmful algal blooms (HABs). Here, we investigated the effects of elevated pCO2 on the physiology of K. mikimotoi. Using semi-continuous cultures under controlled laboratory conditions, growth, photosynthesis and inorganic carbon acquisition were determined over 4-6 week incubations at ambient (390ppmv) and elevated pCO2 levels (1000 ppmv and 2000 ppmv)...
2017: PloS One
https://www.readbyqxmd.com/read/28813416/large-turbulent-reservoirs-of-cold-molecular-gas-around-high-redshift-starburst-galaxies
#2
E Falgarone, M A Zwaan, B Godard, E Bergin, R J Ivison, P M Andreani, F Bournaud, R S Bussmann, D Elbaz, A Omont, I Oteo, F Walter
Starburst galaxies at the peak of cosmic star formation are among the most extreme star-forming engines in the Universe, producing stars over about 100 million years (ref. 2). The star-formation rates of these galaxies, which exceed 100 solar masses per year, require large reservoirs of cold molecular gas to be delivered to their cores, despite strong feedback from stars or active galactic nuclei. Consequently, starburst galaxies are ideal for studying the interplay between this feedback and the growth of a galaxy...
August 14, 2017: Nature
https://www.readbyqxmd.com/read/28813066/multivalent-mesoporous-silica-nanoparticles-photo-delivering-nitric-oxide-with-carbon-dots-as-fluorescence-reporters
#3
Damien Afonso, Sabrina Valetti, Aurore Fraix, Claudia Bascetta, Salvatore Petralia, Sabrina Conoci, Adam Feiler, Salvatore Sortino
Amino-terminated mesoporous silica nanoparticles embedding carbon dots (MSCD) formed by calcination were functionalized with a nitric oxide (NO) photodonor (1) to give a robust MSCD-1 conjugate. The intense fluorescence of MSCDs was strongly quenched in MSCD-1 by effective energy transfer. Visible light excitation of MSCD-1 liberates NO, suppresses the energy transfer mechanism and leads to concomitant fluorescence restoration of the MSCD scaffold, which acts as an optical reporter for the released NO. The MSCD-1 hybrid is also able to encapsulate the highly hydrophobic photosensitizer temoporfin, preserving the fluorescence reporting function...
August 16, 2017: Nanoscale
https://www.readbyqxmd.com/read/28813042/the-carotenoid-pathway-what-is-important-for-excitation-quenching-in-plant-antenna-complexes
#4
Kieran F Fox, Vytautas Balevičius, Jevgenij Chmeliov, Leonas Valkunas, Alexander V Ruban, Christopher D P Duffy
Plant light-harvesting is regulated by the Non-Photochemical Quenching (NPQ) mechanism involving the reversible formation of excitation quenching sites in the Photosystem II (PSII) antenna in response to high light. While the major antenna complex, LHCII, is known to be a site of NPQ, the precise mechanism of excitation quenching is not clearly understood. A preliminary model of the quenched crystal structure of LHCII implied that quenching arises from slow energy capture by Car pigments. It predicted a thoroughly quenched system but offered little insight into the defining aspects of this quenching...
August 16, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28812944/binding-forces-between-a-novel-schiff-base-palladium-ii-complex-and-two-carrier-proteins-human-serum-albumi-and%C3%AE-lactoglobulin
#5
Somaye Shahraki, Ali Heydari
Ligand binding studies on carrier proteins are crucial in determining the pharmacological properties of drug candidates. Here, a new palladium(II) complex was synthesized and characterized. The in vitro binding studies of this complexwith two carrier proteins, human serum albumin (HSA) and β-lactoglobulin (βLG) was investigated by employing biophysical techniques as well as computational modeling. The experimental results showed thatthe Pd(II) complex interacted with two carrier proteins with moderate binding affinity (Kb ~̴ 0...
August 16, 2017: Journal of Biomolecular Structure & Dynamics
https://www.readbyqxmd.com/read/28812745/hysteresis-and-bonding-reconstruction-in-the-pressure-induced-b3-b1-phase-transition-of-3c-sic
#6
Miguel A Salvadó, R Franco, Pilar Pertierra, T Ouahrani, J M Recio
The determination of kinetic factors affecting phase metastability is crucial for the design of materials out of the ambient conditions. At a given temperature, the kinetic barrier associated with the reconstruction of the bonding network of a pressure-induced phase transition can be only overcome at pressures where the available vibrational energy of the system is equal or higher than the corresponding activation energy. Our work demonstrates that these pressures provide boundaries to hysteresis cycles that can be evaluated following a three-step computational strategy: (i) total energy electronic structure calculations, (ii) determination of vibrational contributions by means of a simple Debye model, and (iii) description of the energetic profile along the transition path in the framework of the martensitic approximation...
August 16, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28811190/how-to-quench-your-thirst-the-effect-of-water-based-products-varying-in-temperature-and-texture-flavour-and-sugar-content-on-thirst
#7
L van Belzen, E M Postma, S Boesveldt
The sensation of thirst plays an important role in the consumption of water or other fluids to rehydrate the body in order to keep bodily functions working properly. An increase in saliva secretion, wetting the mouth by ingestion of liquids, and cooling and sour components in products can alleviate this sensation already before absorption of fluids by the body. This study aimed to investigate the thirst-quenching ability of water-based products differing in temperature and texture (cold solids and cool liquids), flavour (flavoured and non-flavoured) and sugar content in two consecutive experiments...
August 12, 2017: Physiology & Behavior
https://www.readbyqxmd.com/read/28811023/agnps-3d-nanostructure-enhanced-electrochemiluminescence-of-cdse-quantum-dot-coupled-with-strand-displacement-amplification-for-sensitive-biosensing-of-dna
#8
Meng Jiao, Guifen Jie, Lu Tan, Shuyan Niu
A novel strategy using Ag nanoparticles-3D (AgNPs-3D) nanostructure enhanced electrochemiluminescence (ECL) of CdSe quantum dots (QDs) coupled with strand displacement amplification (SDA) for sensitive biosensing of DNA was successfully designed. The prepared CdSe QDs with intense ECL were assembled on the poly (diallyldimethylammonium chloride) (PDDA) graphene oxide (GO) nanocomposites modified electrode, then gold nanoparticles (NPs) as the quenching probe was conjugated to the QDs, ECL signal was efficiently quenched...
August 29, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/28810226/rapid-removal-of-organic-pollutants-by-activation-sulfite-with-ferrate
#9
Jing Zhang, Liang Zhu, Zhenyu Shi, Ying Gao
With the addition of sulfite, almost complete removal of seven out of eight tested contaminants, i.e. benzotriazole, phenol, ciprofloxacin, methyl blue, rhodamine B, methyl orange and sulfamethoxazole, was observed in 30 s except for sulfamethoxazole at pH 9.0, while Fe(VI) alone only resulted in less than 6% removal. In this study, the mechanism of sulfite/Fe(VI) process was explored for the first time. Firstly, sulfite attacks Fe(VI) via a 1-e(-) transfer forming the primary sulfite radical (SO3(-)), then SO3(-) reacts rapidly with oxygen in a diffusion controlled rate to form a much more reactive peroxyl radical SO5(-), which further reacts with HSO3(-) and produces SO4(-)...
July 19, 2017: Chemosphere
https://www.readbyqxmd.com/read/28810178/distance-dependent-fluorescence-quenching-and-enhancement-of-gold-nanoclusters-by-gold-nanoparticles
#10
Haiyan Qin, Diao Ma, Jianxiu Du
The interaction between fluorescent gold nanoclusters (AuNCs) and gold nanoparticles (AuNPs) has been investigated. It was observed that the fluorescence of AuNCs was remarkably quenched when direct contact with AuNPs. The fluorescence quenching of AuNCs by AuNPs was dynamic quenching and exhibited size-dependent property. A larger size of AuNPs displayed a stronger quenching effect and gave a larger quenching constant. When a silica spacer shell was introduced between AuNPs and AuNCs, a fluorescence enhancement of AuNCs by Au@SiO2 NPs was observed...
August 10, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28809982/coordination-polymer-derived-nano-sized-zinc-ferrite-with-excellent-performance-in-nitro-explosive-detection
#11
Debal Kanti Singha, Partha Mahata
Herein, a mixed metal coordination polymer, {(H2pip)[Zn1/3Fe2/3(pydc-2,5)2(H2O)]·2H2O} 1 {where H2pip = piperazinediium and pydc-2,5 = pyridine-2,5-dicarboxylate}, was successfully synthesized using a hydrothermal technique. To confirm the structure and phase purity of 1, single crystals of an isomorphous pure Fe compound, {(H2pip)[Fe(pydc-2,5)2(H2O)]·2H2O} 1a, were synthesized based on similar synthetic conditions. Single crystal X-ray data of 1a confirmed the one-dimensional anionic metal-organic coordination polymer hydrogen bonded with protonated piprazine (piperazinediium) and lattice water molecules...
August 15, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28809978/phase-separation-dynamics-of-polydisperse-colloids-a-mean-field-lattice-gas-theory
#12
Pablo de Castro, Peter Sollich
New insights into phase separation in colloidal suspensions are provided via a dynamical theory based on the polydisperse lattice-gas model. The model gives a simplified description of polydisperse colloids, incorporating a hard-core repulsion combined with polydispersity in the strength of the attraction between neighbouring particles. Our mean-field equations describe the local concentration evolution for each of an arbitrary number of species, and for an arbitrary overall composition of the system. We focus on the predictions for the dynamics of colloidal gas-liquid phase separation after a quench into the coexistence region...
August 15, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28809962/nonlinear-behavior-and-fluctuation-induced-dynamics-in-the-photosensitive-belousov-zhabotinsky-reaction
#13
Valérie Voorsluijs, Ioannis G Kevrekidis, Yannick De Decker
The photosensitive Belousov-Zhabotinsky (pBZ) reaction has been used extensively to study the properties of chemical oscillators. In particular, recent experiments revealed the existence of complex spatiotemporal dynamics for systems consisting of coupled micelles (V < 10(-21) L) or droplets (V ≈ [10(-8)-10(-11)] L) in which the pBZ reaction takes place. These results have been mostly understood in terms of reaction-diffusion models. However, in view of the small size of the droplets and micelles, large fluctuations of concentrations are to be expected...
August 15, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28809819/tamra-tamra-fluorescence-quenching-systems-for-the-activity-assay-of-alkaline-phosphatase
#14
Akio Shiba, Emiko Kinoshita-Kikuta, Eiji Kinoshita, Tohru Koike
We introduce two types of fluorescence-quenching assay for alkaline phosphatases (APs) by using a carboxytetramethyl-rhodamine (TAMRA)-labeled phosphate-binding tag molecule (TAMRA-Phos-tag). In the first assay, TAMRA-labeled O-phosphorylethanolamine (TAMRA-PEA) was used as an artificial AP-substrate. TAMRA-Phos-tag specifically captured TAMRA-PEA to form a 1:1 complex at pH 7.4; the intensity of the fluorescence peak of the complex at 580 nm (λex = 523 nm) was significantly reduced to 32% of the average value for the two individual components as a result of the mutual approach of the TAMRA moieties...
August 15, 2017: Sensors
https://www.readbyqxmd.com/read/28809466/tuning-phase-composition-of-polymer-nanocomposites-towards-high-energy-density-and-high-discharge-efficiency-by-non-equilibrium-processing
#15
Jianyong Jiang, Xin Zhang, Zhenkang Dan, Jing Ma, Yuanhua Lin, Ming Li, Ce-Wen Nan, Yang Shen
Polymer nanocomposite dielectrics with high energy density and low loss are major enablers for a number of applications in modern electronic and electrical industry. Conventional fabrication of nanocomposites by solution routes involves equilibrium process which is slow and results in structural imperfections, hence high leakage current and compromised reliability of the nanocomposites. We propose and demonstrate that a non-equilibrium process, which synergistically integrates electrospinning, hot-pressing and thermal quenching, is capable of yielding nanocomposites of very high quality...
August 15, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28808713/a-smart-organic-gel-template-as-metal-cation-and-inorganic-anion-sensor
#16
Novina Malviya, Mriganka Das, Poulami Mandal, Suman Mukhopadhyay
A carboxamide based molecule has shown unique gelation property in an aqueous mixture of DMF or DMSO. The gel itself has shown aggregation-induced fluorescence enhanced emission (AIEE), which can be utilized effectively in sensing ferrous and ferric ions as both of them switch off the fluorescence completely. An investigation by IR spectroscopy reveals an enhanced π interaction of nitrile group with the iron center and this could be the possible reason behind the complete quenching of AIEE. This molecule was further investigated for the formation of metallogels for a wide array of cations, which in turn can act in tandem to behave as a dynamic array to detect several anions by either switching off or switching on the emission property of the metallogels...
August 15, 2017: Soft Matter
https://www.readbyqxmd.com/read/28808388/caesalpinia-crista-linn-induces-protection-against-dna-and-membrane-damage
#17
R Sunil Kumar, Ramesh Balenahalli Narasingappa, Chandrashekhar G Joshi, Talakatta K Girish, Ananda Danagoudar
BACKGROUND: Caesalpinia crista is a medicinal herb used to cure various ailments in subtropical and tropical regions of Southeast Asia. OBJECTIVE: The objective of this evaluation of C. crista against free radical induced DNA and erythrocyte damage. MATERIALS AND METHODS: The profiles of polyphenol and flavonoid were quantified through reversed-phase high-performance liquid chromatography. Free radical induced DNA and membrane damage were performed using H2O2 as oxidative agent...
July 2017: Pharmacognosy Magazine
https://www.readbyqxmd.com/read/28808106/quantifying-the-efficiency-of-photoprotection
#18
REVIEW
Alexander V Ruban
A novel emerging technology for the assessment of the photoprotective 'power' of non-photochemical fluorescence quenching (NPQ) has been reviewed and its insightful outcomes are explained using several examples. The principles of the method are described in detail as well as the work undertaken for its justification. This pulse amplitude modulated chlorophyll fluorescence approach has been applied for the past 5 years to quantify the photoprotective effectiveness of the NPQ and the light tolerance in Arabidopsis plants grown under various light conditions, during ontogenetic development as well as in a range of mutants impaired in carotenoid and protein biosynthesis...
September 26, 2017: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
https://www.readbyqxmd.com/read/28808100/hacking-the-thylakoid-proton-motive-force-for-improved-photosynthesis-modulating-ion-flux-rates-that-control-proton-motive-force-partitioning-into-%C3%AE-%C3%AF-and-%C3%AE-ph
#19
REVIEW
Geoffry A Davis, A William Rutherford, David M Kramer
There is considerable interest in improving plant productivity by altering the dynamic responses of photosynthesis in tune with natural conditions. This is exemplified by the 'energy-dependent' form of non-photochemical quenching (qE), the formation and decay of which can be considerably slower than natural light fluctuations, limiting photochemical yield. In addition, we recently reported that rapidly fluctuating light can produce field recombination-induced photodamage (FRIP), where large spikes in electric field across the thylakoid membrane (Δψ) induce photosystem II recombination reactions that produce damaging singlet oxygen ((1)O2)...
September 26, 2017: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
https://www.readbyqxmd.com/read/28808031/changes-in-aggregation-states-of-light-harvesting-complexes-as-a-mechanism-for-modulating-energy-transfer-in-desert-crust-cyanobacteria
#20
Leeat Bar Eyal, Reza Ranjbar Choubeh, Eyal Cohen, Ido Eisenberg, Carmen Tamburu, Márta Dorogi, Renata Ünnep, Marie-Sousai Appavou, Reinat Nevo, Uri Raviv, Ziv Reich, Győző Garab, Herbert van Amerongen, Yossi Paltiel, Nir Keren
In this paper we propose an energy dissipation mechanism that is completely reliant on changes in the aggregation state of the phycobilisome light-harvesting antenna components. All photosynthetic organisms regulate the efficiency of excitation energy transfer (EET) to fit light energy supply to biochemical demands. Not many do this to the extent required of desert crust cyanobacteria. Following predawn dew deposition, they harvest light energy with maximum efficiency until desiccating in the early morning hours...
August 14, 2017: Proceedings of the National Academy of Sciences of the United States of America
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