Photoacoustic, EPR and electrical conductivity investigations of three synthetic mineral pigments: hematite, goethite and magnetite

Guskos, N.; Papadopoulos, G.; Likodimos, V.; Patapis, S.K.; Yarmis, D.; Przepiera, A.; Przepiera, K.; Majszczyk, J.; Typek, J.; Wabia, M.; Aidinis, Konstantinos; Drążek, Zygmunt

doi:10.1016/s0025-5408(02)00742-0

Cited by 134 publications

(65 citation statements)

References 14 publications

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“…where γ is a coefficient related to thermal properties of a given sample and characteristics of the spectrometer, k the probability of non-radiative transition from the exited state, and A abs the absorbance of sample [15]. Two kinds of relaxation processes should be considered, the radiative and non-radiative ones, which occur after excitation of electrons by the electromagnetic radiation.…”

Section: Resultsmentioning

confidence: 99%

Photoacoustic response of a common starfish tissue

Guskos¹,

Majszczyk²,

Typek³

et al. 2013

Ukr. J. Phys. Opt.

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Abstract.A sample of common starfish (Asterias Rubens) tissue has been prepared in the shape of a film to study its photoacoustic (PA) response. A broad absorption band in the PA spectrum is detected in the visible region (a peak at about 570 nm), while the ultraviolet region is distinguished by the absorption bands originating from π → π* and π → n charge transfer transitions. The visible PA spectrum strongly depends on decomposition of sample in the open air. The PA spectrum measured by us is very similar to those obtained earlier for the other living organisms, e.g. Trunculariopis Trunculus and Sea Urchin. The absorption band near 570 nm is similar to that found for spermidine, which is of importance in the information transfer to DNA. The results obtained in this work confirm experimentally that geologically very old organisms have been absorbing especially intensely in that part of solar spectrum for which the water is transparent.

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Section: Resultsmentioning

confidence: 99%

Photoacoustic response of a common starfish tissue

Guskos¹,

Majszczyk²,

Typek³

et al. 2013

Ukr. J. Phys. Opt.

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“…The most important characteristic of magnetite as a promoter for DIET is its conductivity. The electrical conductivity and resistivity of magnetite are 2.5 × 10 2 Ω•cm −2 and 0.000005 MΩ•cm, respectively (electrical resistivity values of hematite and goethite are 2 and 16 MΩ•cm, respectively) [51].…”

Section: Iron Oxidesmentioning

confidence: 97%

Role and Potential of Direct Interspecies Electron Transfer in Anaerobic Digestion

et al. 2018

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Anaerobic digestion (AD) is an effective biological treatment for stabilizing organic compounds in waste/wastewater and in simultaneously producing biogas. However, it is often limited by the slow reaction rates of different microorganisms' syntrophic biological metabolisms. Stable and fast interspecies electron transfer (IET) between volatile fatty acid-oxidizing bacteria and hydrogenotrophic methanogens is crucial for efficient methanogenesis. In this syntrophic interaction, electrons are exchanged via redox mediators such as hydrogen and formate. Recently, direct IET (DIET) has been revealed as an important IET route for AD. Microorganisms undergoing DIET form interspecies electrical connections via membrane-associated cytochromes and conductive pili; thus, redox mediators are not required for electron exchange. This indicates that DIET is more thermodynamically favorable than indirect IET. Recent studies have shown that conductive materials (e.g., iron oxides, activated carbon, biochar, and carbon fibers) can mediate direct electrical connections for DIET. Microorganisms attach to conductive materials' surfaces or vice versa according to particle size, and form conductive biofilms or aggregates. Different conductive materials promote DIET and improve AD performance in digesters treating different feedstocks, potentially suggesting a new approach to enhancing AD performance. This review discusses the role and potential of DIET in methanogenic systems, especially with conductive materials for promoting DIET.

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“…The second suggestion has been to consider the question whether this radiation could act like a 'spark' and provide energy for different metabolic processes [8]. In particular, the PAS has demonstrated that the absorption band peaked at about 470 nm (similar as in hematite) is peculiar for the living mater [7,8,14,15]. It would be interesting to search for a similar absorption band in plants.…”

Section: Introductionmentioning

confidence: 99%

Photoacoustic spectra of green and red leaves of ficus Benjamina plant

Guskos¹,

Majszczyk²,

Typek³

et al. 2013

Ukr. J. Phys. Opt.

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Abstract. Tissue samples of a ficus Benjamina plant are prepared in the shape of thick film for photoacoustic spectroscopy studies. Two absorption bands in the electromagnetic photoacoustic (PA) spectrum are detected in the visible range. They are peaked at about 398 and 670 nm for a green leaf, and 544 and 570 nm for a red leaf. The absorption bands detected in the ultraviolet range are attributed to π  π* and π  n charge transfer transitions. The visible PA spectra strongly depend on the processes responsible for colouring of leaves. The absorption band at 670 nm could be related to photosynthesis. The absorption band observed at 398 nm for the green leaf disappears for the red one, though a different band located at 544 nm appears. The absorption spectra measured in this work are closely similar to those obtained earlier for the other living organisms. The absorption band near 544 nm is close to that found for spermidine, which is important in the information transfer to DNA. The results obtained in this work confirm experimentally that the red leaves absorb particularly strongly in that spectral region of solar radiation, which is intensely radiated in autumn.

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Photoacoustic, EPR and electrical conductivity investigations of three synthetic mineral pigments: hematite, goethite and magnetite

Cited by 134 publications

References 14 publications

Photoacoustic response of a common starfish tissue

Photoacoustic response of a common starfish tissue

Role and Potential of Direct Interspecies Electron Transfer in Anaerobic Digestion

Photoacoustic spectra of green and red leaves of ficus Benjamina plant

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