Clear evidence of fluorescence resonance energy transfer in gas-phase ions

Fluorescence resonance energy transfer (FRET) is a distance-sensitive method that correlates changes in fluorescence intensity with conformational changes, for example, of biomolecules in the cellular environment. Applied to the gas phase in combination with Fourier transform ion cyclotron resonance mass spectrometry, it opens up possibilities to define structural/conformational properties of molecular ions, in the absence of solvent, and without the need for purification of the sample. For successfully observing FRET in the gas phase it is important to find suitable fluorophores. In this study several fluorescent dyes were examined, and the correlation between solution-phase and gas-phase fluorescence data were studied. For the first time, FRET in the gas phase is demonstrated unambiguousl

Integrating microalgae production with anaerobic digestion: a biorefinery approach

This is the peer reviewed version of the following article: [Uggetti, E. , Sialve, B. , Trably, E. and Steyer, J. (2014), Integrating microalgae production with anaerobic digestion: a biorefinery approach. Biofuels, Bioprod. Bioref, 8: 516-529. doi:10.1002/bbb.1469], which has been published in final form at https://doi.org/10.1002/bbb.1469. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-ArchivingIn the energy and chemical sectors, alternative production chains should be considered in order to simultaneously reduce the dependence on oil and mitigate climate change. Biomass is probably the only viable alternative to fossil resources for production of liquid transportation fuels and chemicals since, besides fossils, it is one of the only available sources of carbon-rich material on Earth. Over recent years, interest in microalgae biomass has grown in both fundamental and applied research fields. The biorefinery concept includes different technologies able to convert biomass into added-value chemicals, products (food and feed) and biofuels (biodiesel, bioethanol, biohydrogen). As in oil refinery, a biorefinery aims at producing multiple products, maximizing the value derived from differences in biomass components, including microalgae. This paper provides an overview of the various microalgae-derived products, focusing on anaerobic digestion for conversion of microalgal biomass into methane. Special attention is paid to the range of possible inputs for anaerobic digestion (microalgal biomass and microalgal residue after lipid extraction) and the outputs resulting from the process (e.g. biogas and digestate). The strong interest in microalgae anaerobic digestion lies in its ability to mineralize microalgae containing organic nitrogen and phosphorus, resulting in a flux of ammonium and phosphate that can then be used as substrate for growing microalgae or that can be further processed to produce fertilizers. At present, anaerobic digestion outputs can provide nutrients, CO2 and water to cultivate microalgae, which in turn, are used as substrate for methane and fertilizer generation.Peer ReviewedPostprint (author's final draft

New Perspectives in the Noble Gas Chemistry Opened by Electrophilic Anions

Binding of noble gases (NGs) is commonly considered to be the realm of highly reactive electophiles with cationic or at least non-charged character. Herein, we summarize our latest results evidencing that the incorporation of a strongly electrophilic site within a rigid cage-like anionic structure offers several advantages that facilitate the binding of noble gases and stabilize the formed NG adducts. The anionic superelectrophiles investigated by us are based on the closo-dodecaborate dianion scaffold. The record holder [B12(CN)11]− binds spontaneously almost all members of the NG family, including the very inert argon at room temperature and neon at 50 K in the gas phase of mass spectrometers. In this perspective, we summarize the argumentation for the advantages of anionic electrophiles in binding of noble gases and explain them in detail using several examples. Then we discuss the next steps necessary to obtain a comprehensive understanding of the binding properties of electrophilic anions with NGs. Finally, we discuss the perspective to prepare bulk ionic materials containing NG derivatives of the anionic superelectophiles. In particular, we explore the role of counterions using computational methods and discuss the methodology, which may be used for the actual preparation of such salts. © Copyright © 2020 Rohdenburg, Azov and Warneke

Fixing the conformation of calix[4]arenes: When are three carbons not enough?

Calix[4]arenes are unique macrocycles that through judicious functionalisation at the lower-rim can be either fixed in one of four conformations or remain conformationally flexible. Introduction of propynyl or propenyl groups unexpectedly provides a new possibility; a unidirectional conformational switch, with the 1,3-alternate and 1,2-alternate conformers switching to the partial cone conformation, whilst the cone conformation is unchanged, under standard experimental conditions. Using 1H NMR kinetic studies, rates of switching have been shown to be dependent on the starting conformation, upper-rim substituent, where reduction in bulk enables faster switching, solvent and temperature with 1,2-alternate conformations switching fastest. Ab initio calculations (DFT) confirmed the relative stabilities of the conformations and point towards the partial cone conformer being the most stable of the four. The potential impact on synthesis through the ‘click’ reaction has been investigated and found not to be significant

Self-Improving Customer Review Response Generation Based on LLMs

Previous studies have demonstrated that proactive interaction with user reviews has a positive impact on the perception of app users and encourages them to submit revised ratings. Nevertheless, developers encounter challenges in managing a high volume of reviews, particularly in the case of popular apps with a substantial influx of daily reviews. Consequently, there is a demand for automated solutions aimed at streamlining the process of responding to user reviews. To address this, we have developed a new system for generating automatic responses by leveraging user-contributed documents with the help of retrieval-augmented generation (RAG) and advanced Large Language Models (LLMs). Our solution, named SCRABLE, represents an adaptive customer review response automation that enhances itself with self-optimizing prompts and a judging mechanism based on LLMs. Additionally, we introduce an automatic scoring mechanism that mimics the role of a human evaluator to assess the quality of responses generated in customer review domains. Extensive experiments and analyses conducted on real-world datasets reveal that our method is effective in producing high-quality responses, yielding improvement of more than 8.5% compared to the baseline. Further validation through manual examination of the generated responses underscores the efficacy our proposed system.Comment: 18 pages, 4 figure, 8 figures in Appendix, accepted to LREC-COLING 2024 worksho

5,11,17,23-Tetra­kis(chloro­meth­yl)-25,26,27,28-tetra­propoxycalix[4]arene

The title calix[4]arene, C44H52Cl4O4, displays the 1,3-alternate conformation with crystallographically imposed twofold symmetry. Four phenolic rings of the calixarene backbone are tilted into the calix cavity, making dihedral angles of 77.42 (2) and 77.71 (2)° with the plane of the four bridging methyl­ene C atoms. Pairs of opposite aromatic rings make dihedral angles of 25.16 (3) and 24.58 (4)° with each other. In the crystal, the calixarene mol­ecules pack with the formation of infinite columns along the b axis. The crystal packing shows a network of C—H⋯Cl contacts, which can be considered as non-classical hydrogen bonds

A family of unsymmetrical hydroxyl-substituted BEDT-TTF donors: syntheses, structures and preliminary thin film studies

Three new unsymmetrical hydroxyl-functionalized donors H1–H3 closely related to hydroxymethyl-BEDT-TTF have been synthesised and characterised. Cyclic voltammetry studies showed that the compounds exhibit reversible two one-electron redox processes typical for BEDT-TTF derivatives. X-ray diffraction studies of H1 and H2 reveal π-stacking interactions between pairs of donors that are organized into distinct H-bonded square motifs and DFT calculations indicate that the HOMO is located on the central 1,3-dithiole rings. Protection of the hydroxyl group with acetyl in 13 eliminates co-facial S...S interactions between the dimers to accommodate the bulkier side chains, but short edge-to-edge S...S contacts offer an alternative pathway for electron mobility. Chemical oxidation of H1 and HMET 2 with I2 afforded single crystals of two 1 : 1 charge transfer salts, 18 and 19. The molecules pack as dimers with close π-stacking interactions between pairs of radical cations whose crystal structures are further stabilized via an interplay of S...S and S...I contacts. Iodine-doped surface conducting polystyrene blend films of H3 deposited on a silica substrate exhibit quasiconducting properties, but afford no OFET response when fabricated into devices. Visible-NIR studies of a doped polystyrene blend film of H3 cast on a glass substrate show absorption bands at λ =9 50 and 3000 nm, consistent with mixed valence states due to the presence of charge-transfer species on the surface of the films

Tratamiento de aguas residuales urbanas mediante lagunas de alta carga: evaluación experimental

[ES] El objetivo del presente estudio es determinar las condiciones de explotación de dos lagunas experimentales que permiten obtener un mayor rendimento de eliminación de la materia orgánica y los nutrientes del agua residual urbana. También se pretende establecer el rendimiento de los decantadores secundarios experimentales utilizados para la separación de la biomasa del fitoplancton que crece en las lagunas. Se han estudiado durante un año dos lagunas de alta carga provistas cada una de un decantador secundario en serie. La eliminación de la materia orgánica y los nutrientes se ha evaluado mediante estrategias operacionales diferenciadas definidas a través del control del tiempo de retención hidraulico. La evolución de la concentración de la biomasa del fitoplancton del líquido de mezcla de las lagunas está controlada por la radiación solar y la temperatura, y no resulta afectada por las diferentes estrategias de explotación adoptadas. El rendimiento anual medio de eliminación de la biomasa del fitoplancton observado en los decantadores secundarios es de 70-80% y no es afectado por las diferentes condiciones operacionales. La concentración media de la materia en suspensión en los efluentes es de 50-60 mg/l. El rendimiento de eliminación de la materia orgánica (DQO) es muy similar en las dos lagunas y no depende de las estrategias operacionales adoptadas. Para que las lagunas de alta carga produzcan un agua equivalente a un efluente secundario es suficiente adoptar un tiempo de retención de 4 dias en primavera y verano, y 8 dias en otoño e invierno. Se puede alcanzar un buen rendimiento de eliminación de nitrógeno aumentando el tiempo de retención durante el otoño y el invierno a 10 dias. Para alcanzar concentraciones de fósforo en el efluente iguales o inferiores a 1 mg/l es necesario dotar al sistema de instalaciones complementarias para su tratamiento.García, J.; Hernández-Mariné, M.; Mujeriego Sahuquillo, R. (1998). Tratamiento de aguas residuales urbanas mediante lagunas de alta carga: evaluación experimental. Ingeniería del Agua. 5(2):35-50. https://doi.org/10.4995/ia.1998.2748SWORD355052Abeliovich, A., (1986) Algae in wastewater oxidation ponas. In: Handbook of Microalgal Mass Culture (Richmond, A. ed.). CRC Press. Boca Ratón, pp. 331-338.APHA-AWWA-WPCF., (1995) Standard Methods for the Examination of Water & Wastewater. 19th edition. American Public Health Association. Washington D.C.Azov, Y. & Shelef, G., (1982) Operation of high-rate oxidation ponds: theory and experiments. Wat. Res.16: 1153-1160.Cromar, N.J., Martin, N.J., Christofi, N., Read, P.A. & Fallowfield H.J. (1991) Determination of nitrogen and phosphorous partitioning within com-ponents ofthe biomass in a high rate algalpond: significance for the coastal environment ofthe treatedeffluent discharge. Wat. Sci. Tech. 23 (6): 251-258.De Pauw, N. & Salomoni, C. (1990) The use of microalgae in wastewater treatment: achievements and constraints. In: Biológical Approach to Sewage Treatment Process: Current Status and Perspectives (Madoni, P. ed.). Perugia. pp. 329-352.El Halouani, H. (1990) Lagunage a Haut Rendement: Caractérisation Physicochimique de l'Ecosystéme. Etude de son Aptitude à l'Elimination de l'Azote et du Phosphore dans l'Epuration des Eaux Usées. Thése de Doctoral. Université de Montpellier I. 154pp.El Halouani, H., Picot, B., Casellas, C., Pena, G. & Bontoux, J. (1993) Elimination de l'azote et du phosphore dans un lagunage à haut rendement. Revue des Sciences de l'Eau 6: 47-61.Fallowfield, H.J. & Garret, M.K. (1985) The treatment of wastes by algal culture. Journal of Applied Bacteriology. 53rd Symposium Supplement. pp. 187-205.García, J. (1996) Eliminació de Matèria Orgànica i Nutients en Llacunes d'Alt Rendiment. Tesi Doctoral. Universitat de Barcelona. 301 pp.Lavoie, A. & De la Noüe, J. (1987) Harvesting of Scenedesmus obliquus in wastewaters: auto- or bioflocculation? Biotech. Bioeng. 30: 852-859.Lincoln, E.P. & Koopman, B. (1986) Bioflocculation of microalgae in mass cultures. In: Algal Biomass Technologies (Barclay, W.R. & Macintosh, R.P. eds.). Nova Hedwigia Beiheft83. pp. 207-211.Nurdogan, Y. & Oswald, W. (1995) Enhanced nutrient removal in high-rate ponds. Wat. Sci. Tech. 31(12): 33-44.Oswald. W.J. (1986) A Syllabus on Waste Pond Fundamentals (Oswald, W.J. ed.).1401 University of California. Berkeley. 187 pp.Oswald, W.J. (1991) Introduction to advanced integrated wastewater ponding systems. Wat. Sci. Tech. 24: 1-7.Oswald, W.J. (1995) Ponds in the twenty-first century. Wat. Sci. Tech. 31 (12): 1-8.Pearson, H.W. (1996) Expanding the horizons of pond technology and application in an environmentally conscious world. Wat. Sci. Tech. 33 (7): 1-10.Picot, B., El Halouani, H., Casellas, C., Moersidik, S. & Bontoux, J. (1991) Nutrient removal by high rate pond system in a Mediterranean climate. Wat. Sci. Tech. 23: 1535-1541Shelef, G. & Azov, Y. (1987) High-rate oxidation onds: the israeli experience. Wat. Sci. Tech. 19: 249-255.Shelef, G., Moraine, R. & Oron, G. (1980) Algal mass production as an integral part of waste treatment & reclamation system. In: Algae Biomass (Shelef, G. & Soeder, C.J. eds.). Elsevier/North Holland Biomedical Press. Amsterdam. pp. 163-190.Sukenik, A. & Shelef, G. (1984) Algal autoflocculation-verification and proposed Mechanism. Biotech. Bioeng. 16: 142-147.WPCF. (1990) Natural Systems for Wastewater Treatment. Manual of practice FD-16. WPCF. Alexandria. 270 pp.Zadorojny, C, Saxton, S. & Finger, R. (1973) Spectrophotometric determination of ammonia. Journal WPCF 45: 905-912

2,3,6,7-Tetra­kis(bromo­meth­yl)naphthalene

The title compound, C14H12Br4, crystallizes with imposed inversion symmetry. In the crystal, the mol­ecules pack in layers parallel to (10). The layers involve two Br⋯Br and one H⋯Br contact. Between the layers, one contact each of types Br⋯Br, H⋯Br and Br⋯π is observed