Mechanically induced chemiluminescence from polymers incorporating a 1,2-dioxetane unit in the main chain

Nature Chemistry, Год журнала: 2012, Номер 4(7), С. 559 - 562

Опубликована: Июнь 1, 2012

Язык: Английский

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Theory and Calculation of the Phosphorescence Phenomenon

Chemical Reviews, Год журнала: 2017, Номер 117(9), С. 6500 - 6537

Опубликована: Апрель 7, 2017

Phosphorescence is a phenomenon of delayed luminescence that corresponds to the radiative decay molecular triplet state. As general property molecules, phosphorescence represents cornerstone problem chemical physics due spin prohibition underlying triplet-singlet emission and because its analysis embraces deep knowledge electronic structure. simplest physical process which provides an example spin-forbidden transformation with characteristic selectivity magnetic field dependence, being model also for more complicated reactions catalysis applications. The bridging in commonly analyzed by perturbation theory, considers intensity borrowing from spin-allowed transitions. In this review, we highlight basic theoretical principles computational aspects estimation various parameters, like intensity, rate constant, lifetime, polarization, zero-field splitting, sublevel population. Qualitative are discussed terms concepts structure–activity relationships, donor–acceptor interactions, vibronic activity, role spin–orbit coupling under charge-transfer perturbations. We illustrate theory highlighting studies classical examples nitrogen oxygen, benzene, naphthalene their azaderivatives, porphyrins, as well reviewing current research on systems electrophosphorescent transition metal complexes, nucleobases, amino acids. furthermore discuss modern cover topics applied relevance, design novel photofunctional materials organic light-emitting diodes (OLEDs), photovoltaic cells, sensors, bioimaging.

Язык: Английский

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Exoplanet Biosignatures: A Review of Remotely Detectable Signs of Life

Astrobiology, Год журнала: 2018, Номер 18(6), С. 663 - 708

Опубликована: Май 4, 2018

In the coming years and decades, advanced space- ground-based observatories will allow an unprecedented opportunity to probe atmospheres surfaces of potentially habitable exoplanets for signatures life. Life on Earth, through its gaseous products reflectance scattering properties, has left fingerprint spectrum our planet. Aided by universality laws physics chemistry, we turn Earth's biosphere, both in present geologic time, analog that aid search life elsewhere. Considering insights gained from modern ancient broader array hypothetical exoplanet possibilities, have compiled a comprehensive overview current understanding potential biosignatures, including gaseous, surface, temporal biosignatures. We additionally survey biogenic spectral features are well known specialist literature but not yet been robustly vetted context briefly review advances assessing biosignature plausibility, novel methods determining chemical disequilibrium remotely obtainable data assessment tools minimum biomass required maintain short-lived gases as atmospheric signatures. focus particularly made since seminal Des Marais et al. The purpose this work is propose new strategies, goal companion articles series, literature, draw meaningful connections between seemingly disparate areas, clear way path forward. Key Words: Exoplanets—Biosignatures—Habitability markers—Photosynthesis—Planetary surfaces—Atmospheres—Spectroscopy—Cryptic biospheres—False positives. Astrobiology 18, 663–708. 1. Introduction 1.1. Requirements 1.2. Exoplanet definitions 1.3. Biosignature categories 2. Evaluating Planetary Habitability 3. Overview Terrestrial Modeling Studies 3.1. Observations earth 3.2. Spectral models 3.3. Photochemical studies terrestrial 3.4. Earth time 4. Gaseous Biosignatures 4.1. 4.2. Earth-like 4.2.1. Oxygen (O2) 4.2.2. Ozone (O3) 4.2.3. Methane (CH4) 4.2.4. Nitrous oxide (N2O) 4.2.5. Sulfur (DMS, DMDS, CH3SH) relation detectable C2H6 4.2.6. Methyl chloride (CH3Cl) 4.2.7. Haze 4.2.8. Other 4.3. “False positives” biotic O2/O3 possible discriminators 4.4. other types 4.5. Effects host star photochemistry 4.6. Impacts flares particle events 5. Surface 5.1. Photosynthesis 5.1.1. Principles photosynthesis 5.1.1.1. Relationship band gap wavelength reductant generation pigment color 5.1.1.2. Uniqueness OP 5.1.2. Photosynthetic pigments phototrophs 5.1.2.1. Structure 5.1.2.2. Light absorption 5.1.3. vegetation “red edge” 5.1.4. Speculation about 5.2. Retinal 5.3. Alternative surface biosignatures: nonphotosynthetic 5.4. False positive biosignatures 5.5. Chiral polarization 5.6. Fluorescence bioluminescence 6. Temporal 6.1. Oscillations 6.2. 7. Assessing Plausibility 7.1. Chemical 7.2. Biomass estimation 7.3. Applications network theory 8. Cryptic Biospheres: Negatives” Life? 9. Prospects Detecting 10. Summary

Язык: Английский

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Bioluminescence in the Ocean: Origins of Biological, Chemical, and Ecological Diversity

Science, Год журнала: 2010, Номер 328(5979), С. 704 - 708

Опубликована: Май 6, 2010

From bacteria to fish, a remarkable variety of marine life depends on bioluminescence (the chemical generation light) for finding food, attracting mates, and evading predators. Disparate biochemical systems diverse phylogenetic distribution patterns light-emitting organisms highlight the ecological benefits bioluminescence, with genetic analyses providing new insights into mechanisms its evolution. The origins functions some bioluminescent systems, however, remain obscure. Here, I review recent advances in understanding ocean future research efforts that will unite molecular details evolutionary relationships.

Язык: Английский

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Dye-containing polymers: methods for preparation of mechanochromic materials

Chemical Society Reviews, Год журнала: 2012, Номер 42(3), С. 857 - 870

Опубликована: Ноя. 27, 2012

The detection of mechanical stress in polymeric materials through optical variations has attracted considerable interest over the past ten years. In this tutorial review, current state knowledge concerning preparation polymers with mechanochromic features is summarized. Two types procedures are illustrated and thoroughly discussed along their respective structure-property relationships: first resides physical dispersion dye form supramolecular aggregates a preformed polymer matrix; second involves covalent insertion chromophoric units into macromolecule backbone or side chains. Herein we review simplicity preparative routes available, influence properties resulting dye-polymer systems, by focussing on most illustrative examples described literature. Special reference made to stimuli-responsiveness as means towards innovative smart intelligent materials.

Язык: Английский

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Chemi- and Bioluminescence of Cyclic Peroxides

Chemical Reviews, Год журнала: 2018, Номер 118(15), С. 6927 - 6974

Опубликована: Март 1, 2018

Bioluminescence is a phenomenon that has fascinated mankind for centuries. Today the and its sibling, chemiluminescence, have impacted society with number of useful applications in fields like analytical chemistry medicine, just to mention two. In this review, molecular-orbital perspective adopted explain behind chemiexcitation both chemi- bioluminescence. First, uncatalyzed thermal dissociation 1,2-dioxetane presented analyzed explain, example, preference triplet excited product states increased yield larger nonreactive substituents. The catalyzed fragmentation reaction related details are then exemplified substituted 1,2-dioxetanone species. particular, singlet case explained. review also examines diversity specific solutions Nature artificial systems difficulties identifying emitting species unraveling color modulation process. subject excited-state without light absorption finally discussed. content should be an inspiration human design new molecular expressing unique light-emitting properties. An appendix describing state-of-the-art experimental theoretical methods used study phenomena serves as complement.

Язык: Английский

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The nature, extent, and ecological implications of marine light pollution

Frontiers in Ecology and the Environment, Год журнала: 2014, Номер 12(6), С. 347 - 355

Опубликована: Авг. 1, 2014

Despite centuries of use, artificial light at night has only recently been recognized as a cause for environmental concern. Its global extent and ongoing encroachment into naturally lit ecosystems sparked scientific interest the many ways in which it may negatively affect human health, societal attitudes, endeavors, biological processes. Yet, perhaps because sources are largely land based, potential pollution to interfere with biology ocean not explored any detail. There is little information on how affects those species, behaviors, interactions that informed by intensity, spectra, periodicity natural nighttime marine ecosystems. Here, we provide an overview pollution, discuss changes physical environment, explore its role shaping

Язык: Английский

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Why artificial light at night should be a focus for global change research in the 21st century

Global Change Biology, Год журнала: 2017, Номер 24(3), С. 872 - 882

Опубликована: Ноя. 10, 2017

The environmental impacts of artificial light at night have been a rapidly growing field global change science in recent years. Yet, pollution has not achieved parity with other phenomena the level concern and interest it receives from scientific community, government nongovernmental organizations. This is despite globally widespread, expanding changing nature night-time lighting immediacy, severity phylogenetic breath its impacts. In this opinion piece, we evidence 10 reasons why should be focus for research 21st century. Our extend beyond those concerned principally environment, to also include on human health, culture biodiversity conservation more generally. We conclude that use will continue raise numerous ecological, health cultural issues, but opportunities exist mitigate by combining novel technologies sound evidence. potential gains appropriate management far indeed may play key role transitioning towards sustainable society.

Язык: Английский

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Not all animals need a microbiome

FEMS Microbiology Letters, Год журнала: 2019, Номер 366(10)

Опубликована: Май 1, 2019

ABSTRACT It is often taken for granted that all animals host and depend upon a microbiome, yet this has only been shown small proportion of species. We propose span continuum reliance on microbial symbionts. At one end are the famously symbiont-dependent species such as aphids, humans, corals cows, in which microbes abundant important to fitness. In middle may tolerate some colonization but minimally or facultatively dependent. other lack beneficial symbionts altogether. While their existence seem improbable, capable limiting growth bodies, microbially independent lifestyle be favored by selection under circumstances. There already evidence several ‘microbiome-free’ lineages represent distantly related branches animal phylogeny. discuss why these have received little attention, highlighting potential contaminants, transients, parasites masquerade also suggest ways explore microbiomes address limitations DNA sequencing. call further research microbiome-free taxa provide more complete understanding ecology evolution macrobe-microbe interactions.

Язык: Английский

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Photoinduced Chemistry in Fluorescent Proteins: Curse or Blessing?

Chemical Reviews, Год журнала: 2016, Номер 117(2), С. 758 - 795

Опубликована: Окт. 18, 2016

Photoinduced reactions play an important role in the photocycle of fluorescent proteins from green protein (GFP) family. Among such processes are photoisomerization, photooxidation/photoreduction, breaking and making covalent bonds, excited-state proton transfer (ESPT). Many these transformations initiated by electron (ET). The quantum yields vary significantly, nearly 1 for ESPT to 10-4-10-6 ET. Importantly, even when relatively small, at conditions repeated illumination overall effect is significant. Depending on task hand, photochemistry regarded either as asset facilitating new applications or a nuisance leading loss optical output. phenomena arising due phototransformations include (i) large Stokes shifts, (ii) photoconversions, photoactivation, photoswitching, (iii) phototoxicity, (iv) blinking, (v) permanent bleaching, (vi) formation long-lived intermediates. focus this review most recent experimental theoretical work photoinduced proteins. We also provide overview photophysics proteins, highlighting interplay between other channels (fluorescence, radiationless relaxation, intersystem crossing). similarities differences with photochemical biological systems dyes discussed.

Язык: Английский

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