The Difference in Sensing Properties Towards Anions between Two Pyridinium Amide-Based Receptors with a Subtle Change of H-Bond Position

2020 ◽  
Vol 17 (6) ◽  
pp. 472-478
Author(s):  
Wei-tao Gong ◽  
Wei-dong Qu ◽  
Guiling Ning

Two pyridinium amide-based receptors L1 and L2 with a small difference of H-bond position of the amide have been synthesized and characterized. Interestingly, they exhibited a huge difference in sensing towards AcO- and H2PO4 -, respectively. Receptor L1 was found to be ‘naked-eye’ selective for AcO- anions, while receptor L2 showed clear fluorescence enhancement selective to H2PO4 - anion. The recognition ability has been established by fluorescence emission, UV-vis spectra, and 1HNMR titration.

2021 ◽  
Vol 11 (5) ◽  
pp. 2339
Author(s):  
Joanna Metlerska ◽  
Till Dammaschke ◽  
Mariusz Lipski ◽  
Irini Fagogeni ◽  
Anna Machoy-Mokrzyńska ◽  
...  

The aim of the present in vitro study was to investigate the effects of 10% and 40% citric acid (CA) on the color of calcium silicate–based cements (CSCs) in comparison to the effects of common root canal irrigants. Samples of six CSCs (n = 6)—ProRoot MTA (Dentsply, Tulsa, OK, USA), Biodentine (Septodont, Saint-Maur-des-Fossés, France), MTA Plus (Avalon Biomed Inc, by Prevest Denpro Limited, Jammu, India), MTA Repair HP (Angelus, Londrina, PR, Brazil), Ortho MTA (BioMTA, Seoul, Korea), and Retro MTA (BioMTA, Seoul, Korea)—were immersed in 10% and 40% CA as well as 15% EDTA, 2% NaOCl, 2% CHX, and 0.9% NaCl for 15 min, 1 h, and 24 h. ΔE values, representing the difference between the final and baseline values of the color components, were then determined using a VITA Easyshade Compact 5.0 spectrophotometer. Naked-eye evaluation of the changes in color and structures of the materials was performed using our own scale. Upon immersion of the materials in both 10% and 40% CA, there were statistically significant differences between spectrophotometric color measurement results for all CSCs (P < 0.05). However, CA does not cause dark discoloration, observable with the naked eye, of any of the materials, such as NaOCl and CHX. Significant statistical differences were also found between all CSCs in terms of submersion duration (P < 0.05). CA, which could be an alternative to EDTA use, caused greater CSCs discoloration and changed some of their structures. Unless required by the therapeutic procedure, clinicians should pay attention to the fact that the irrigant may affect the CSCs discoloration and minimize the contact time of irrigant with CSCs.


Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4215
Author(s):  
Hiromi Kimura ◽  
Go Fuseya ◽  
Satoshi Takeya ◽  
Akihiro Hachikubo

Knowledge of carbon isotope fractionation is needed in order to discuss the formation and dissociation of naturally occurring CO2 hydrates. We investigated carbon isotope fractionation during CO2 hydrate formation and measured the three-phase equilibria of 12CO2–H2O and 13CO2–H2O systems. From a crystal structure viewpoint, the difference in the Raman spectra of hydrate-bound 12CO2 and 13CO2 was revealed, although their unit cell size was similar. The δ13C of hydrate-bound CO2 was lower than that of the residual CO2 (1.0–1.5‰) in a formation temperature ranging between 226 K and 278 K. The results show that the small difference between equilibrium pressures of ~0.01 MPa in 12CO2 and 13CO2 hydrates causes carbon isotope fractionation of ~1‰. However, the difference between equilibrium pressures in the 12CO2–H2O and 13CO2–H2O systems was smaller than the standard uncertainties of measurement; more accurate pressure measurement is required for quantitative discussion.


2012 ◽  
Vol 239-240 ◽  
pp. 1000-1003
Author(s):  
Zhao Quan Cai ◽  
Hui Hu ◽  
Tao Xu ◽  
Wei Luo ◽  
Yi Cheng He

It is urgent to study how to effectively identify color of moving objects from the video in the information era. In this paper, we present the color identification methods for moving objects on fixed camera. One kind of the methods is background subtraction that recognizes the foreground objects by compare the difference of pixel luminance between the current image and the background image at the same coordinates. Another kind is based on the statistics of HSV color and color matching which makes the detection more similar to the color identification of the human beings. According to the experiment results, after the completion of the background modelling, our algorithm of background subtraction, statistics of the HSV color and the color matching have strong color recognition ability on the moving objects of video.


2020 ◽  
Vol 8 (44) ◽  
pp. 15622-15625
Author(s):  
Hao Guo ◽  
Xin Yan ◽  
Bing Lu ◽  
Jin Wang ◽  
Xiaolei Yuan ◽  
...  

Two-step sequential fluorescence emission enhanced supramolecular nanoparticles are constructed from pillar[5]arene based host–guest interaction and a linear amphiphile. These supramolecular nanoparticles can be applied in mitochondria-targeted live cell imaging.


2013 ◽  
Vol 634-638 ◽  
pp. 2462-2465
Author(s):  
Wen Xian Li ◽  
Bo Yang Ao ◽  
Jing Zhang

A novel ligand with double sulfinyl groups, bis(benzylsulfinyl)methane L, was synthesized by a new method. Its novel ternary complex, has been synthesized [using L as the first ligand, and dipyridyl L' as the second ligand]. In order to study the effect of the second ligand on the fluorescence properties of rare-earth sulfoxide complex, a novel binary europium complex has been synthesized. Photoluminescent measurement showed that the first ligand L could efficiently transfer the energy to Eu (III) ions in the complex. Furthermore, the detailed luminescence analyses on the rare earth complexes indicated that the ternary Eu (III) complex manifested stronger fluorescence intensities, longer lifetimes, and higher fluorescence quantum efficiencies than the binary Eu (III) materials. The fluorescence emission intensities and fluorescence lifetimes of the ternary complex enhanced more obviously than the binary complex.


2020 ◽  
Vol 27 (1) ◽  
pp. 127-142
Author(s):  
Pedro Meza-López ◽  
◽  
Mayra K. Trujillo-Delgado ◽  
Alan U. Burciaga-Álvarez ◽  
Ricardo de la Cruz-Carrera ◽  
...  

Introduction: The primary wood processing industry releases greenhouse gases (GHGs); their mitigation involves measuring the carbon footprint.Objective: To estimate the carbon footprint of two forestry companies dedicated to the primary transformation of wood.Materials and methods: Companies established as organizational boundaries L1 and L2 have two (Q1 and Q2) and one (D) sawmill, respectively. The operational limits were A1 (direct emissions from fossil fuel consumption), A2 (indirect emissions from electricity consumption) and A3 (emission sources not owned by L1 and L2). GHG emissions were calculated in two annuities with the method of using documented activity data and emission factors level 1. The annuities were compared with the Student’ t-test and Wilcoxon test, and the sawmills with the Kruskal-Wallis test.Results and discussion: The estimated carbon footprint for L1 was 480.06 tCO2e·year-1, where A1, A2 and A3 represented 29.32 %, 14.59 % and 56.09 %, respectively. L2 had a footprint of 230.56 tCO2e·year-1 of which 9.39 %, 11.78 % and 78.83 % corresponded to the categories A1, A2 and A3, respectively. The cumulative uncertainty was within a fair range of accuracy (±25 %). Only the direct GHG emissions between L1 annuities were statistically different (P < 0.05). Mechanical technology made the difference in GHG emissions among sawmills (P < 0.05).Conclusions: The carbon footprint is inherent to the energy used; energy management ensures the mitigation of GHG emissions.


Author(s):  
Ben McFarland

Let’s move to a vantage point a little quieter: the surface of the moon. It is so still that Neil Armstrong’s footprints remain undisturbed. The only reason the US flag there appears to “fly” is that a wire holds it up. The moon and Mercury stayed still as Mars, Venus, and Earth moved on down the road of geological development. The moon is a “steady” environment, a word whose Middle English roots are appropriately tangled with the word for “sterile.” Nothing moves on the moon, but in its sky Mars, Venus, and Earth move in their orbits, just as they moved on in complexity 4 billion years ago. Out of the whole solar system, Mars and Venus are the most like Earth in size, position, and composition. Mars is smaller, but Venus could be Earth’s twin in size. If Earth and Venus were separated at birth, then something happened to obscure the family resemblance: liquid water brought life. To chemists, liquid is the third phase of matter, between solid and gas, and its presence made all the difference. Mars gleams a bright blood red even to the naked eye, while Venus is choked with thick yellow bands of clouds. Mars is cold enough to have carbon dioxide snow, while Venus is hot enough to melt tin and boil water. Earth’s blue oceans and green continents provide a bright, primary contrast. These three siblings have drastically different fortunes. At first, they looked the same, colored with black mafic basalt and glowing red magma. The original planets were all so hot that their atmospheres were driven off into space. The oceans and the air came from within. Steam condensed into oceans on each planet’s cool basalt surface. Oceans changed the planet. Water is a transformative chemical, small yet highly charged, seeping into the smallest cracks, dissolving what it can and carrying those things long distances. Venus, Earth, and Mars do not look like the moon because they have been washed in water. Mars is dry now, but the Curiosity rover left no doubt that the red planet was first blue with water.


Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3678
Author(s):  
Yaohui Xu ◽  
Chi Deng ◽  
Zhigang Xiao ◽  
Chang Chen ◽  
Xufeng Luo ◽  
...  

Fe3O4@SiO2 nanospheres with a core–shell structure were synthesized and functionalized with bis(2-pyridylmethyl)amine (BPMA). The photoresponses of the as-obtained Fe3O4@SiO2-BPMA for Cr3+, Cd2+, Hg2+ and Pb2+ ions were evaluated through irradiation with a 352 nm ultraviolet lamp, and Fe3O4@SiO2-BPMA exhibited remarkable fluorescence enhancement toward the Cd2+ ion. The adsorption experiments revealed that Fe3O4@SiO2-BPMA had rapid and effective adsorption toward the Cd2+ ion. The adsorption reaction was mostly complete within 30 min, the adsorption efficiency reached 99.3%, and the saturated adsorption amount was 342.5 mg/g based on Langmuir linear fitting. Moreover, Fe3O4@SiO2-BPMA displayed superparamagnetic properties with the saturated magnetization of 20.1 emu/g, and its strong magnetic sensitivity made separation simple and feasible. Our efforts in this work provide a potential magnetic functionalized nanosensor for naked-eye identification and adsorption toward the Cd2+ ion.


The Analyst ◽  
2019 ◽  
Vol 144 (10) ◽  
pp. 3357-3363 ◽  
Author(s):  
Marina A. Dominguez ◽  
Matías Insausti ◽  
Romina Ilari ◽  
Graciela P. Zanini

Fluorescence emission enhancement by adsorption as a promising tool for the development of future green sensors.


2018 ◽  
Vol 14 ◽  
pp. 2236-2241 ◽  
Author(s):  
Xiayang Huang ◽  
Xinghua Zhang ◽  
Tianxin Qian ◽  
Junwei Ma ◽  
Lei Cui ◽  
...  

A water-soluble 2,2′-biphen[4]arene (2,2’-CBP4) containing eight carboxylato moieties was synthesized and characterized. Its complexation behavior towards two alkaloids, palmatine (P) and berberine (B), was investigated by means of fluorescence and 1H NMR spectroscopy in aqueous phosphate buffer solution (pH 7.4). In the presence of 2,2’-CBP4, 1H NMR signals of P and B displayed very large upfield shifts, indicating the formation of inclusion complexes with strong binding affinities. Fluorescence titration experiments showed that P and B exhibited dramatic fluorescence enhancement of more than 600 times upon complexation with 2,2’-CBP4. Particularly, the fluorescence intensity is strong enough to be readily distinguished by the naked eye. Although the two guests have similar structures, the association constant of B with 2,2’-CBP4 (K a = (2.29 ± 0.27) × 106 M−1) is 3.9 times larger than that of P (K a = (5.87 ± 0.24) × 105 M−1).


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