scholarly journals Luminescent sensors and photonic switches

2001 ◽  
Vol 73 (3) ◽  
pp. 503-511 ◽  
Author(s):  
A. Prasanna de Silva ◽  
David B. Fox ◽  
Thomas S. Moody ◽  
Sheenagh M. Weir
Keyword(s):  
Small Molecules ◽  
Excited States ◽  
Logic Gates ◽  
Xor Gate ◽  
Luminescent Sensors ◽  
Photonic Switches ◽  
Multiple Receptors ◽  
Molecular Scale ◽  
First Time ◽  
Internal Charge Transfer

The principles of photochemistry continue to fuel progress in luminescent sensors and photonic switches. Examples of sensors based on photoinduced electron transfer (PET) are discussed, including those which form the basis of successful systems used in physiology and medicine. More complex formats usually involve multiple receptors. One progression takes us to lanthanide complexes enabled with sensory capabilities. Another path takes us to molecular-scale implementation of logic gates such as AND and INHIBIT. Such luminescent switches can be enriched by combination with nonluminescent cousins. The latter are based on internal charge-transfer excited states (ICT). An example of rudimentary arithmetic at the molecular scale is presented by running a luminescent AND gate in parallel with a nonluminescent XOR gate. Thus, small molecules can process small numbers for the first time outside of our brains.

Frequency Encoded All Optical Tri-state Logic Gates NOT and NAND Using Semiconductor Optical Amplifier Based Interferometric Switches

2020 ◽  
Vol 10 (4) ◽  
pp. 369-380
Author(s):  
K. Maji ◽  
K. Mukherjee ◽  
A. Raja
Keyword(s):  
Semiconductor Optical Amplifier ◽  
Extinction Ratio ◽  
Optical Power ◽  
Logic Gates ◽  
Optical Amplifier ◽  
All Optical ◽  
State Frequency ◽  
Spontaneous Noise ◽  
First Time ◽  
Practical Feasibility

All optical tri-state frequency encoded logic gates NOT and NAND are proposed and numerically investigated using TOAD based interferometric switch for the first time to the best of our knowledge. The optical power spectrum, extinction ratio, contrast ration, and amplified spontaneous noise are calculated to analyze and confirm practical feasibility of the gates. The proposed device works for low switching energy and has high contrast and extinction ratio as indicated in this work.

scholarly journals Structure of the master regulator Rns reveals an inhibitor of enterotoxigenic Escherichia coli virulence regulons

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Charles R. Midgett ◽  
Kacey Marie Talbot ◽  
Jessica L. Day ◽  
George P. Munson ◽  
F. Jon Kull
Keyword(s):  
Escherichia Coli ◽  
Small Molecules ◽  
Family Member ◽  
Shigella Flexneri ◽  
Decanoic Acid ◽  
Enterotoxigenic Escherichia Coli ◽  
Gram Negative Bacteria ◽  
Enteric Infections ◽  
First Time ◽  
Arac Family

AbstractEnteric infections caused by the gram-negative bacteria enterotoxigenic Escherichia coli (ETEC), Vibrio cholerae, Shigella flexneri, and Salmonella enterica are among the most common and affect billions of people each year. These bacteria control expression of virulence factors using a network of transcriptional regulators, some of which are modulated by small molecules as has been shown for ToxT, an AraC family member from V. cholerae. In ETEC the expression of many types of adhesive pili is dependent upon the AraC family member Rns. We present here the 3 Å crystal structure of Rns and show it closely resembles ToxT. Rns crystallized as a dimer via an interface similar to that observed in other dimeric AraC’s. Furthermore, the structure of Rns revealed the presence of a ligand, decanoic acid, that inhibits its activity in a manner similar to the fatty acid mediated inhibition observed for ToxT and the S. enterica homologue HilD. Together, these results support our hypothesis that fatty acids regulate virulence controlling AraC family members in a common manner across a number of enteric pathogens. Furthermore, for the first time this work identifies a small molecule capable of inhibiting the ETEC Rns regulon, providing a basis for development of therapeutics against this deadly human pathogen.

Furil based ionic small molecules for green emitting non-doped LECs with improved color purity

2021 ◽  
Author(s):  
Jino C John ◽  
Kanagaraj Shanmugasundaram ◽  
Archana Puthanveedu ◽  
Hariventhan Ragupathi ◽  
Gopakumar Gopinadhanpillai ◽  
...  
Keyword(s):  
Small Molecules ◽  
Color Purity ◽  
First Time

Two novel furil based small molecules FlBzPy and FlThPy were designed and synthesized with simple synthetic procedures for the first time for the LEC application. The optical, thermal, electronic, electroluminescent,...

Direct emission from quartet excited states triggered by upconversion phenomena in solid-phase synthesized fluorescent lead-free organic–inorganic hybrid compounds

2019 ◽  
Vol 7 (46) ◽  
pp. 26504-26512 ◽  
Author(s):  
Atanu Jana ◽  
Shynggys Zhumagali ◽  
Qiankai Ba ◽  
Arun S. Nissimagoudar ◽  
Kwang S. Kim
Keyword(s):  
Excited States ◽  
Solid Phase ◽  
Lead Free ◽  
Inorganic Hybrid ◽  
Hybrid Compounds ◽  
Direct Emission ◽  
First Time

We report, for the first time, the solid-phase gram-scale synthesis of two lead-free, zero-dimensional (0D) fluorescent organic–inorganic hybrid compounds, [Bu4N]2[MnBr4] (1) and [Ph4P]2[MnBr4] (2).

Ln3+ post-functionalized metal–organic frameworks for color tunable emission and highly sensitive sensing of toxic anions and small molecules

2016 ◽  
Vol 40 (5) ◽  
pp. 4654-4661 ◽  
Author(s):  
Ji-Na Hao ◽  
Bing Yan
Keyword(s):  
Small Molecules ◽  
White Light ◽  
Light Emission ◽  
Metal Organic Frameworks ◽  
White Light Emission ◽  
Luminescent Sensors ◽  
Highly Sensitive ◽  
Color Tunable ◽  
Metal Organic ◽  
Tunable Emission

Ln3+-functionalized MOFs with tunable color and white-light emission were fabricated and developed as luminescent sensors for anions and small molecules.

Quintet States 1s2s2p2 5P and 1s2p3 5So for Be-Like Systems

2019 ◽  
Vol 74 (9) ◽  
pp. 743-749
Author(s):  
Kai Kai Li ◽  
Lin Zhuo ◽  
Yan Sun ◽  
Bing Cong Gou
Keyword(s):  
Variational Method ◽  
Excited States ◽  
Relativistic Effect ◽  
Oscillator Strengths ◽  
Isoelectronic Sequence ◽  
The Core ◽  
Transition Wavelength ◽  
Computational Data ◽  
First Time ◽  
Hyperfine Structures

AbstractBy systematic Rayleigh–Ritz variation calculations, the energies are reported for the core-excited states 1s2s2p2 5P and 1s2p3 5So in the Be-like isoelectronic sequence (Z = 11–20). Energy corrections, including the restricted variational method, mass polarisation, and relativistic effect, are considered to improve the accuracy of energy. The oscillator strengths and transition wavelength between these states are also reported. Computational data on hyperfine structures presented in this paper are calculated for the first time.

scholarly journals An Architecture of 2-Dimensional 4-Dot 2-Electron QCA Full Adder and Subtractor with Energy Dissipation Study

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Md. Abdullah-Al-Shafi ◽  
Ali Newaz Bahar
Keyword(s):  
Energy Dissipation ◽  
Cellular Automata ◽  
Single Layer ◽  
Full Adder ◽  
Energy Depletion ◽  
Xor Gate ◽  
Quantum Dot Cellular Automata ◽  
Novel Technology ◽  
Computational Procedures ◽  
First Time

Quantum-dot cellular automata (QCA) is the beginning of novel technology and is capable of an appropriate substitute for orthodox semiconductor transistor technology in the nanoscale extent. A competent adder and subtractor circuit can perform a substantial function in devising arithmetic circuits. The future age of digital techniques will exercise QCA as preferred nanotechnology. The QCA computational procedures will be simplified with an effective full adder and subtractor circuit. The deficiencies of variations and assembly still endure as a setback in QCA based outlines, and being capricious and inclined to error is the limitation of these circuits. In this study, a new full adder and subtractor design using unique 3-input XOR gate with cells redundancy is proposed. This designs can be utilized to form different expedient QCA layouts. The structures are formed in a single layer deprived of cross-wiring. Besides, this study is directed to the analysis of the functionality and energy depletion possessions of the outlined full adder and subtractor circuits. For the first time, QCADesigner-Energy (QD-E) version 2.0.3 tool is utilized to find the overall depleted energy. The attained effects with QCADesigner have verified that the outlined design has enhanced functioning in terms of intricacy, extent, and latency in contrast to the earlier designs. Moreover, the redundant form of full adder and subtractor has uncomplicated and robust arrangement competing typical styles.

scholarly journals Confinement and Diffusion of Small Molecules in a Molecular-Scale Tunnel

2020 ◽  
Vol 167 (2) ◽  
pp. 023505
Author(s):  
Kanchan Suklal Chavan ◽  
Scott Calabrese Barton
Keyword(s):  
Small Molecules ◽  
Molecular Scale ◽  
And Diffusion

THE HYDROGEN–CHLORINE SYSTEM IN THE MM PRESSURE RANGE: I. ENERGY DISTRIBUTION AMONG VIBRATIONALLY EXCITED STATES

1964 ◽  
Vol 42 (10) ◽  
pp. 2176-2192 ◽  
Author(s):  
F. D. Findlay ◽  
J. C. Polanyi
Keyword(s):  
Excited States ◽  
Rotational Temperature ◽  
Relative Rate ◽  
Infrared Emission ◽  
Vibrational States ◽  
Vibrationally Excited ◽  
Experimental Conditions ◽  
Reduced Pressure ◽  
A Chain ◽  
First Time

When atomic plus molecular hydrogen coming from a Wood's discharge tube are mixed with molecular chlorine, infrared emission is observed (1). At low reagent pressures, ~10−2 mm Hg, this emission can be related to the relative rate of the reaction H + Cl2 → HCl†ν + Cl proceeding to form HCl in vibrationally excited states ν = 1–6, of the ground electronic state. In the present work this system has been investigated for the first time at ~100 × the reagent pressure (~1 mm Hg). The reaction was shown to proceed by a chain mechanism. The translational–rotational temperature was 1300 ± 100 °K under the experimental conditions normally used. The vibrational distribution was notable for the presence of vibrators in levels ν = 7 and 8, which are respectively 4 and 10 kcal higher in energy than the exothermicity of the H + Cl2 reaction. The population in these levels appeared to be related to that in the levels with [Formula: see text]; it was proposed that vibrational–vibrational exchange among these lower levels was responsible for populating the higher ones. A simple model yielded a collision efficiency for HCl†ν=1 + HCl†ν=6 → HCl†ν=7 + HCl†ν=0, of Z1,6t = 6 × 103 collisions per transfer. Addition of HCl to the reaction mixture brought about a redistribution among vibrationally excited states indicative of a fast vibrational transfer, HClν=0 + HCl†ν=2 → 2 HCl†ν=1.At reduced pressure of HCl† the stationary-state distribution among higher vibrational states approximated closely to that observed at 10−2 mm Hg total pressure (where collisional deactivation is insignificant), suggesting that collisional deactivation was not of major importance even at the pressure used in the present work. In order to account for the high translational–rotational temperature, in the absence of substantial vibrational deactivation, it was necessary to suppose that the greater part of the energy liberated by the reaction H + Cl2 went directly into translational and rotational motion of the products.

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