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2. Molecular structure and composition elucidation of an industrial humin and its fractions

Author

Constant, S, Lancefield, CS, Vogelzang, W, Purushothaman, RKP, Frissen, AE, Houben, K, de Peinder, P, Baldus, M, Weckhuysen, BM, van Es, DS, Bruijnincx, PCA, Constant, S, Lancefield, CS, Vogelzang, W, Purushothaman, RKP, Frissen, AE, Houben, K, de Peinder, P, Baldus, M, Weckhuysen, BM, van Es, DS, and Bruijnincx, PCA

Abstract

Humins, (side-)products of the acid-catalysed dehydration of carbohydrates, will be produced in substantial quantities with the development of industrial biorefining processes. Most structural knowledge about such humins is based on synthetic model humins prepared at lab-scale from typical carbohydrate(-derived) compounds. Here, we report the first extensive characterisation study of an industrial humin. The soluble humin was generated from pilot plant-scale methanolic cyclodehydration of D-fructose to 5-methoxymethyl-2-furfural (MMF), as part of the Avantium YXY® process to produce FDCA. Purification of the industrial humin followed by fractionation allowed isolation of a water-insoluble, high molecular weight fraction (WIPIH) and a water-soluble, low-to-middle molecular weight soluble fraction (WES). Characterisation by elemental analysis, thermogravimetry, IR and NMR spectroscopy and size exclusion chromatography provided a detailed picture of the humin structure in both fractions. Aided by a comprehensive NMR spectral library of furanic model compounds, we identified the main furanic building blocks and inter-unit linkages and propose a structure for this industrial humin sample. The WIPIH and WES fractions were found to be composed of furanic rings interconnected by short aliphatic chains containing a wide range of functionalities including alcohols, ethers, carboxylic acids, esters, aldehydes and ketones. The low level of crosslinking and high functional group content of the industrial humin differ from the more extensively studied, (highly over-)condensed synthetic model humins, towards which they can be considered intermediates. The structural and compositional insights into the nature of an actual industrial humin open up a broad spectrum of valorisation opportunities.

Published
2024

3. In vitro safety and performance evaluation of a seawater solution enriched with copper, hyaluronic acid, and eucalyptus for nasal lavage

Author

Huang S, Constant S, De Servi B, Meloni M, Culig J, Bertini M, and Saaid A

Subjects
Common cold, hypertonic seawater, nasal irrigation, pathogens, ATP release, decongestion, Medical technology, R855-855.5
Abstract

Song Huang,1 Samuel Constant,1 Barbara De Servi,2 Marisa Meloni,2 Josip Culig,3 Marco Bertini,4 Amina Saaid5 1Epithelix, Geneva, Switzerland; 2Department of in Vitro Research, VitroScreen, Milan, 20149, Italy; 3Department of Pharmacology, University of Applied Health Sciences, Zagreb, 10000, Croatia; 4R&D Department, Laboratori Baldacci SpA, Pisa, Italy; 5Department of R&D and Innovation, Laboratoire Fumouze, Levallois-Perret, 92686, FranceCorrespondence: Marco BertiniLaboratori Baldacci SpA, Via S. Michele degli Scalzi, 73, 56124 Pisa, ItalyTel +39 5 031 3271Fax +39 5 057 0170Email bertini@baldaccilab.comBackground: The common cold is a viral infectious disease with symptoms such as runny nose, sore throat, and mainly, nasal congestion. State-of-the-art therapeutic approaches focus on alleviating the symptoms of this disease by non-invasive and simple-to-use methods. Nasal irrigation is one of the most accepted approaches to ease nasal congestion which, if left untreated, has a negative impact on the quality of life of patients.Purpose: In this study, the safety and efficacy of a novel hypertonic seawater solution for nasal lavage enriched with hyaluronic acids, eucalyptus oil, copper, and manganese salts (Stérimar Stop & Protect Cold and Flu; SSPCF) have been investigated in vitro.Methods: An in vitro 3D reconstituted human nasal epithelium tissue model, MucilAir™, has been used in this study to investigate the safety of SSPCF on nasal epithelium by measuring transepithelial electrical resistance (TEER), lactate dehydrogenase (LDH), and interleukin-8 (IL-8) secretion. The efficacy of SSPCF was measured by mucociliary clearance (MCC), ATP release, Alcian blue and aquaporin (AQP3) stainings.Results: SSPCF treatment respected nasal epithelium tissue integrity and enhanced barrier function without inducing a cytotoxic response. Secreted LDH and IL-8 levels were similar to untreated controls. MCC rate was increased 2.5-fold and ATP release decreased 87% upon SSPCF treatment, indicating improved decongestion activity. SSPCF treatment after hypotonic stress helped recover cellular organization, as shown by Alcian blue and AQP3 staining assays.Conclusion: SSPCF appears as a safe and effective nasal irrigation formula that may alleviate the symptoms associated with common cold such as nasal congestion.Keywords: common cold, hypertonic seawater, nasal irrigation, pathogens, ATP release, decongestion

Published
2019

11. ColdZyme Maintains Integrity in SARS-CoV-2-Infected Airway Epithelia

Author

Posch, W., Vosper, J., Zaderer, V., Noureen, A., Constant, S., Bellmann-Weiler, R., Lass-Flörl, C., and Wilflingseder, D.

Subjects
SARS-CoV-2, COVID-19, Virus Attachment, Bronchi, Epithelial Cells, Complement C3, Respiratory Mucosa, anaphylatoxins, Antiviral Agents, Microbiology, Immunity, Innate, ColdZyme, QR1-502, antiviral response, Nasal Mucosa, airway epithelia, Humans, Oral Sprays, Research Article
Abstract

Although our understanding of COVID-19 continuously progresses, essential questions regarding prophylaxis and treatment remain open. A hallmark of severe SARS-CoV-2 infection is a hitherto-undescribed mechanism leading to excessive inflammation and tissue destruction associated with enhanced pathogenicity and mortality., SARS-CoV-2 infection causing the COVID-19 pandemic calls for immediate interventions to avoid viral transmission, disease progression, and subsequent excessive inflammation and tissue destruction. Primary normal human bronchial epithelial cells are among the first targets of SARS-CoV-2 infection. Here, we show that ColdZyme medical device mouth spray efficiently protected against virus entry, excessive inflammation, and tissue damage. Applying ColdZyme to fully differentiated, polarized human epithelium cultured at an air-liquid interphase (ALI) completely blocked binding of SARS-CoV-2 and increased local complement activation mediated by the virus as well as productive infection of the tissue model. While SARS-CoV-2 infection resulted in exaggerated intracellular complement activation immediately following infection and a drop in transepithelial resistance, these parameters were bypassed by single pretreatment of the tissues with ColdZyme mouth spray. Crucially, our study highlights the importance of testing already evaluated and safe drugs such as ColdZyme mouth spray for maintaining epithelial integrity and hindering SARS-CoV-2 entry within standardized three-dimensional (3D) in vitro models mimicking the in vivo human airway epithelium.

Published
2021
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13. Towards More Predictive, Physiological and Animal-free In Vitro Models: Advances in Cell and Tissue Culture 2020 Conference Proceedings

Author

Singh, B, Abdelgawad, ME, Ali, Z, Bailey, J, Budyn, E, Civita, P, Clift, MJD, Connelly, JT, Constant, S, Hittinger, M, Kandarova, H, Kearns, VR, Kiuru, T, Kostrzewski, T, Kress, S, Durban, VM, Lehr, C-M, McMillan, H, Metz, JK, Monteban, V, Movia, D, Neto, C, Owen, C, Paasonen, L, Palmer, KA, Pilkington, GJ, Pilkington, K, Prina-Mello, A, Roper, C, Sheard, J, Smith, S, Turner, JE, Roy, I, Tutty, MA, Velliou, E, Wilkinson, JM, Singh, B, Abdelgawad, ME, Ali, Z, Bailey, J, Budyn, E, Civita, P, Clift, MJD, Connelly, JT, Constant, S, Hittinger, M, Kandarova, H, Kearns, VR, Kiuru, T, Kostrzewski, T, Kress, S, Durban, VM, Lehr, C-M, McMillan, H, Metz, JK, Monteban, V, Movia, D, Neto, C, Owen, C, Paasonen, L, Palmer, KA, Pilkington, GJ, Pilkington, K, Prina-Mello, A, Roper, C, Sheard, J, Smith, S, Turner, JE, Roy, I, Tutty, MA, Velliou, E, and Wilkinson, JM

Abstract

Experimental systems that faithfully replicate human physiology at cellular, tissue and organ level are crucial to the development of efficacious and safe therapies with high success rates and low cost. The development of such systems is challenging and requires skills, expertise and inputs from a diverse range of experts, such as biologists, physicists, engineers, clinicians and regulatory bodies. Kirkstall Limited, a biotechnology company based in York, UK, organised the annual conference, Advances in Cell and Tissue Culture (ACTC), which brought together people having a variety of expertise and interests, to present and discuss the latest developments in the field of cell and tissue culture and in vitro modelling. The conference has also been influential in engaging animal welfare organisations in the promotion of research, collaborative projects and funding opportunities. This report describes the proceedings of the latest ACTC conference, which was held virtually on 30th September and 1st October 2020, and included sessions on in vitro models in the following areas: advanced skin and respiratory models, neurological disease, cancer research, advanced models including 3-D, fluid flow and co-cultures, diabetes and other age-related disorders, and animal-free research. The roundtable session on the second day was very interactive and drew huge interest, with intriguing discussion taking place among all participants on the theme of replacement of animal models of disease.

Published
2021

23. Dual-balloon assisted super-selective embolisation of high flow arterial venous fistula within a transplant kidney

Author

Ffrench-Constant, S, Weerakoon, N, Amin, R, Taube, D, and Hamady, MS

Abstract

Background In this case report, we describe a novel application of the technique of ‘dual-balloon assisted’ cannulation and embolisation of a high flow arterial venous fistula (AVF) in transplant kidney, where attempts at standard and previously described embolisation techniques were proving difficult to achieve. Case presentation Seventy year old gentleman with renal transplant presenting with high output cardiac failure and deteriorating renal function. Angiography demonstrated high flow traumatic AV fistula within transplanted kidney, secondary to multiple biopsies. Attempts at guidewire and guiding sheath placement and stability for occlusion plug deployment were failing due to combination of very high back-flow pressures within the AVF and challenging vascular anatomy; with an aneurysmal, tortuous iliac artery as well as intra renal transplanted vessels. A combination of angioplasty and remodeling aortic balloons in the transplant artery and the host external iliac vein respectively, facilitated stabilization of guiding sheath and hence controlled delivery of an occlusion plug from the venous side of the fistula. The fistula was successfully embolised, leading to complete resolution of patient symptoms and improvement of renal function beyond his previous baseline. Conclusions Percutaneous embolisation is an established technique to treat iatrogenic AVF in transplant kidneys. High flow pressure through an AVF, as demonstrated in this case, can cause difficulty and raise safety issues in accessing and embolising the AVF using previously described techniques. This case report describes an effective and novel application of the technique of using a second balloon in the host common iliac vein to; lower flow pressure, stabilise the guidewires during plug deployment and prevent displacement of wires and/or plug into the common iliac vein.

Published
2018

32. Spectroscopic characterization of 1450 nm semiconductor pump laser structures for Raman amplifiers.

Author

Constant, S. B., Tomic, S., Lock, D., Sale, T. E., Sweeney, S. J., and Hosea, T. J. C.

Subjects
*SEMICONDUCTORS, *ELECTRONIC amplifiers, *PHOTOLUMINESCENCE
Abstract

In order to characterize various different epilayer designs for semiconductor Raman amplifier pump lasers, combined electromodulated reflectance (ER) and photoluminescence (PL) studies were performed on wafer samples of InP/InGaAsP/InGaAsP edge-emitter laser structures in the infrared spectral region. Information about the quantum well (QW) transitions is obtained primarily from the ER, with additional corroboration provided by the PL. The ER spectra are fitted with a line shape model to obtain the ground-state and higher-order QW transition energies, which are found to agree well with theoretically calculated values. The ER spectra also provide the waveguide core and barrier compositions and built-in electric fields in the laser structures. The information provided by ER studies on the prefabrication wafers is found to corroborate well with diagnostic spontaneous emission measurements performed on actual laser devices fabricated from the same wafer batches. [ABSTRACT FROM AUTHOR]

Published
2003
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36. Feasibility of a 3D human airway epithelial model to study respiratory absorption

Author

Reus, A.A., Maas, W.J.M., Jansen, H.T., Constant, S., Staal, Y.C.M., Triel, J.J. van, and Kuper, C.F.

Subjects
TARA - Toxicology and Risk Assessment PHS - Pharmacokinetics & Human Studies (tot 2013 daarna KFP), EELS - Earth, Environmental and Life Sciences TNO Bedrijven, Respiratory absorption, Biomedical Innovation, 3D human airway model, Life Triskelion BV, Biology, Healthy Living
Abstract

The respiratory route is an important portal for human exposure to a large variety of substances. Consequently, there is an urgent need for realistic in vitro strategies for evaluation of the absorption of airborne substances with regard to safety and efficacy assessment. The present study investigated feasibility of a 3D human airway epithelial model to study respiratory absorption, in particular to differentiate between low and high absorption of substances. Bronchial epithelial models (MucilAir™), cultured at the air–liquid interface, were exposed to eight radiolabeled model substances via the apical epithelial surface. Absorption was evaluated by measuring radioactivity in the apical compartment, the epithelial cells and the basolateral culture medium. Antipyrine, caffeine, naproxen and propranolol were highly transported across the epithelial cell layer (>5%), whereas atenolol, mannitol, PEG-400 and insulin were limitedly transported (

Published
2014

39. Inspired Sinewave technique to non-invasive lung function testing an introduction and update of recent developments

Author

Phi Anh Phan, Ffrench-Constant, S., Farmery, A., and Hahn, C. E. W.

Abstract

Inspired Sinewave is a novel technique to measure dead space, alveolar volume, and pulmonary blood flow noninvasively. In this paper, we describe a brief introduction to the principle of the technique, which involves forcing inspired concentrations to oscillate sinusoidally and measuring responding expired concentrations. Then, we give some updates to the recent developments of the device. These include accuracy and robustness studies of the device on bench lungs and volunteers, and study of lung volume change from sitting to supine. The success of these studies is a big step forward to make this novel device a useful clinical tool. The paper concludes with a description of future work.

Published
2013

43. Microbial activity in basaltic glasses from Cayman Trough

Author

Monnier, C., Humler, E., Chavrit, D., Constant, S., Joubert, Y., De Lépinay B., Mercier, Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), and Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU.STU]Sciences of the Universe [physics]/Earth Sciences, ComputingMethodologies_GENERAL
Abstract

Poster

Published
2008

45. Optical Microresonators used for Stabilisation and Miniaturisation of High Spectral Purity Microwave Sources for Space Applications

Author

Constant , S., Merrer , Pierre-Henri, Onillon , Bertrand, Dollat , Xavier, Lacroix , Pierre, Llopis , Olivier, Ghisa , Laura, Dumeige , Yannick, Feron , Patrice, Cibiel , Gilles, Laboratoire d'analyse et d'architecture des systèmes (LAAS), Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées, Fonctions Optiques pour les Technologies de l'informatiON (FOTON), Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-Télécom Bretagne, Centre National d'Études Spatiales [Toulouse] (CNES), Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Laboratoire d'analyse et d'architecture des systèmes [Toulouse] ( LAAS ), Institut National Polytechnique [Toulouse] ( INP ) -Institut National des Sciences Appliquées - Toulouse ( INSA Toulouse ), Institut National des Sciences Appliquées ( INSA ) -Institut National des Sciences Appliquées ( INSA ) -Université Paul Sabatier - Toulouse 3 ( UPS ) -Centre National de la Recherche Scientifique ( CNRS ), Fonctions Optiques pour les Technologies de l'informatiON ( FOTON ), Télécom Bretagne-École Nationale Supérieure des Sciences Appliquées et de Technologie ( ENSSAT ) -Université de Rennes 1 ( UR1 ), Université de Rennes ( UNIV-RENNES ) -Université de Rennes ( UNIV-RENNES ) -Institut National des Sciences Appliquées ( INSA ) -Centre National de la Recherche Scientifique ( CNRS ), Centre National d'Etudes Spatiales ( CNES ), Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-Télécom Bretagne-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], [ PHYS.PHYS.PHYS-OPTICS ] Physics [physics]/Physics [physics]/Optics [physics.optics]
Abstract

International audience; The use of optical resonators for microwave oscillator stabilization is discussed in this paper. This recently proposed approach could be a disruptive technology, in a near future, giving access to high performance in a small volume thanks to the extremely high optical Q factor and to the small dimensions of the optical resonator. Many topologies can be chosen for the electrical-optical oscillator (OEO), and many different approaches can be investigated for the resonator itself, and the coupling techniques. This paper gives an overview of all these techniques, together with some preliminary results on a dedicated resonator measurement bench.

Published
2006

46. A characterization bench to analyse various types of optical WGM resonators for high spectral purity microwave sources applications

Author

Constant , S., Merrer , Pierre-Henri, Onillon , Bertrand, Lacroix , Pierre, Dollat , Xavier, Llopis , Olivier, Ghisa , Laura, Dumeige , Yannick, Feron , Patrice, Cibiel , Gilles, Laboratoire d'analyse et d'architecture des systèmes [Toulouse] ( LAAS ), Institut National Polytechnique [Toulouse] ( INP ) -Institut National des Sciences Appliquées - Toulouse ( INSA Toulouse ), Institut National des Sciences Appliquées ( INSA ) -Institut National des Sciences Appliquées ( INSA ) -Université Paul Sabatier - Toulouse 3 ( UPS ) -Centre National de la Recherche Scientifique ( CNRS ), Fonctions Optiques pour les Technologies de l'informatiON ( FOTON ), Télécom Bretagne-École Nationale Supérieure des Sciences Appliquées et de Technologie ( ENSSAT ) -Université de Rennes 1 ( UR1 ), Université de Rennes ( UNIV-RENNES ) -Université de Rennes ( UNIV-RENNES ) -Institut National des Sciences Appliquées ( INSA ) -Centre National de la Recherche Scientifique ( CNRS ), Centre National d'Etudes Spatiales ( CNES ), Laboratoire d'analyse et d'architecture des systèmes (LAAS), Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées, Fonctions Optiques pour les Technologies de l'informatiON (FOTON), Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-Télécom Bretagne, Centre National d'Études Spatiales [Toulouse] (CNES), Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-Télécom Bretagne-Centre National de la Recherche Scientifique (CNRS), Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse III - Paul Sabatier (UT3), and Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP)

Subjects
[PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], Materials science, [ PHYS.PHYS.PHYS-OPTICS ] Physics [physics]/Physics [physics]/Optics [physics.optics], business.industry, Physics::Optics, 02 engineering and technology, Laser, 01 natural sciences, law.invention, 010309 optics, Resonator, 020210 optoelectronics & photonics, Optics, law, Optical cavity, 0103 physical sciences, Spectral width, 0202 electrical engineering, electronic engineering, information engineering, Optoelectronics, Whispering-gallery wave, business, Optical filter, Microwave, Spectral purity
Abstract

International audience; We have set up a characterization bench to test the optical and microwave properties of high Q optical whispering gallery mode resonators. The bench comprises nanometer scale precision 3D displacement stages mounted on an anti-vibration table in order to get a very fine coupling between the optical resonator and the tapered fibers used for coupling. This bench can be adapted to different types of resonators: μ- and mmspheres of SiO2 or monocrystalline disks. In this paper we present several approaches which have been investigatedin order to test these resonators. Different types of optical sources have been used: a broadband 'white light' source around 1550 nm, a T-control free-running laser emitting at ~1550 nm, an external cavity laser with a narrow spectral width. We have also performed a temperature control of the sphere. Finally, we are trying to lock the laser on a sphere optical mode in order to get a stable system.

Published
2006
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47. Impact of nitrate supply in C and N assimilation in the parasitic plant Striga hermonthica (Del.) Benth (Scrophulariaceae) and its host Sorghum bicolor L

Author

Philippe SIMIER, Constant, S., Degrande, D., Moreau, C., Robins, R. J., Fer, A., Thalouarn, P., Chimie Et Interdisciplinarité : Synthèse, Analyse, Modélisation (CEISAM), Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), and Université de Nantes (UN)-Université de Nantes (UN)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)

Abstract

0140-7791

Published
2006

49. A Wireless Internet-Based Observatory: The Real-time Coastal Observation Network (ReCON)

Author

NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION ANN ARBOR MI GREAT LAKES ENVIRONMENTAL RESEARCH LAB, Ruberg, S. A., Muzzi, R. W., Brandt, S. B., Lane, J. C., Miller, T. C., Gray, J. J., Constant, S. A., Downing, E. J., NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION ANN ARBOR MI GREAT LAKES ENVIRONMENTAL RESEARCH LAB, Ruberg, S. A., Muzzi, R. W., Brandt, S. B., Lane, J. C., Miller, T. C., Gray, J. J., Constant, S. A., and Downing, E. J.

Abstract

ReCON, a coastal observation network with nodes on Lakes Michigan, Huron, and Erie, has been designed to allow flexible deployment of coastal access points and simplified integration of sensor packages. The system provides continuous observations of chemical, biological, and physical parameters, facilitates modification of sampling parameters in anticipation of episodic events, facilitates collection of field samples in response to episodic events, supports long term research and contributes to sensor and system development. The system currently supports projects addressing harmful algal bloom (HAB) detection, human health observations related to beach closures and drinking water processing concerns, rip current warnings, integrated ecosystem assessment, and public access to historic shipwrecks at the Thunder Bay National Marine Sanctuary. ReCON system development relies on wireless broadband technology and a network-based underwater hub designed to allow expansion via satellite nodes. The system architecture allows simplified integration of sensors from various institutions through guest ports. Access to and control of instrumentation is made available to the scientific community and educational institutions through the internet. A real-time database management system provides data and information for forecast model initial conditions, forecast verification, public information, and educational outreach. The technology demonstrated on the ReCON project represents an important contribution to the success of regional coastal ocean observing systems. The pervasiveness of wireless internet technology in coastal regions represents an opportunity to significantly expand high bandwidth coastal observation capabilities., See also ADM002047. Presented at the MTS/IEEE Oceans 2007 Conference held in Vancouver, Canada on Sep 29-Oct 4, 2007. U.S. Government or Federal Purpose Rights License.. The original document contains color images.

Published
2007

50. Expression of the psbA gene during photoinhibition and recovery in Synechocystis PCC 6714: inhibition and damage of transcriptional and translational machinery prevent the restoration of photosystem II activity

Author

Constant, S., Perewoska, I., Alfonso Lozano, Miguel, and Kirilovsky, D.

Subjects
photoinhibition, psbA gene, Synechocystis, D1 protein, photosystem II
Abstract

13 Pags.- 8 Figs., The D1 reaction center protein of the photosystem II complex is very sensitive to light. It is continuously being damaged, degraded and resynthesized. Under high light, photosystem II inactivation is observed. This is because the rate of D1 damage is faster than that of its replacement. This process can be reversed if exposure to high light is not too long. In this work we study the changes that occur in the transcriptional and translational machinery that could lead to irreversible photoinhibition in Synechocystis PCC 6714. In the first minutes of photoinhibition, high light induced an accumulation of psbA mRNA due to an increase in psbA transcription initiation. Although the transcription rate of other photosynthetic genes (e.g. psaE and cpcB-cpcA) declined, the high turnover of the psbA transcript was maintained for a long time. When the light stress was too long, the stability of psbA mRNA increased and the psbA transcription rate appeared to decrease. A high level of psbA mRNA was maintained even though translation no longer occurred and the cells were unable to recover. Experiments to measure newly synthesized D1 incorporation into the thylakoid membranes during recovery in the presence of rifampicin showed that the initiation of transcription was not required for translation of psbA mRNA when photoinhibition was still reversible. Since psbA translation did not depend on the level of psbA transcript or on the initiation of psbA transcription, we propose that damage to the translational machinery also occurred during light stress, leading to the inhibition of D1 synthesis and to irreversible photoinhibition.

Published
1997

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