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The popular genetic model organism Caenorhabditis elegans (C. elegans) encodes 34 globins, whereby the few that are well-characterized show divergent properties besides the typical oxygen carrier function. Here, we present a biophysical characterization and expression analysis of C. elegans globin-3 (GLB-3). GLB-3 is predicted to exist in two isoforms and is expressed in the reproductive and nervous system. Knockout of this globin causes a 99% reduction in fertility and reduced motility. Spectroscopic analysis reveals that GLB-3 exists as a bis-histidyl-ligated low-spin form in both the ferrous and ferric heme form. A function in binding of diatomic gases is excluded on the basis of the slow CO-binding kinetics. Unlike other globins, GLB-3 is also not capable of reacting with H2O2, H2S, and nitrite. Intriguingly, not only does GLB-3 contain a high number of cysteine residues, it is also highly stable under harsh conditions (pH = 2 and high concentrations of H2O2). The resilience diminishes when the N-and C-terminal extensions are removed. Redox potentiometric measurements reveal a slightly positive redox potential (+8 +/- 19 mV vs. SHE), suggesting that the heme iron may be able to oxidize cysteines. Electron paramagnetic resonance shows that formation of an intramolecular disulphide bridge, involving Cys70, affects the heme-pocket region. The results suggest an involvement of the globin in (cysteine) redox chemistry.

Graphical abstract, Globin-coupled sensors (GCS) usually consist of three domains: a sensor/globin, a linker, and a transmitter domain. The globin domain (GD), activated by ligand binding and/or redox change, induces an intramolecular signal transduction resulting in a response of the transmitter domain. Depending on the nature of the transmitter domain, GCSs can have different activities and functions, including adenylate and di-guanylate cyclase, histidine kinase activity, aerotaxis and/or oxygen sensing function. The gram-negative delta-proteobacterium Geobacter sulfurreducens expresses a protein with a GD covalently linked to a four transmembrane domain, classified, by sequence similarity, as GCS (GsGCS). While its GD is fully characterized, not so its transmembrane domain, which is rarely found in the globin superfamily. In the present work, GsGCS was characterized spectroscopically and by native ion mobility-mass spectrometry in combination with cryo-electron microscopy. Although lacking high resolution, the oligomeric state and the electron density map were valuable for further rational modeling of the full-length GsGCS structure. This model demonstrates that GsGCS forms a transmembrane domain-driven tetramer with minimal contact between the GDs and with the heme groups oriented outward. This organization makes an intramolecular signal transduction less likely. Our results, including the auto-oxidation rate and redox potential, suggest a potential role for GsGCS as redox sensor or in a membrane-bound e−/H+ transfer. As such, GsGCS might act as a player in connecting energy production to the oxidation of organic compounds and metal reduction. Database searches indicate that GDs linked to a four or seven helices transmembrane domain occur more frequently than expected.

Identifying the manufacturer of historical wall tiles is often based on visual inspection by an expert. This is a subjective and time-consuming approach, as it can only be performed on sight by few experts. In this work, it is evaluated whether Raman and X-ray fluorescence (XRF) spectroscopy can create a chemical fingerprint to discriminate the tile manufacturers based on their provenance. Using both analytical techniques and combining this with chemometrical analysis, different historical Belgian tile manufacturers are characterized. We were successful in discriminating the brown from the white glazes, as well as for discriminating most Belgian tile manufacturers based on their origin. For the latter, only the results of the white glazes were used. The results show that both Raman and XRF parameters are important markers, which is underlining the significance of their combined use and opens perspectives for their non-destructive use to distinguish the tile manufacturers, in situ.

The evolutionary and ontogenetic changes from water-to air-breathing result in major changes in the cardio-respiratory systems. However, the potential changes in hemoglobin's (Hb) oxygen binding properties during ontogenetic transitions to air-breathing remain poorly understood. Here we investigated Hb multiplicity and O(2 )binding in hemolysates and Hb components from juveniles and adults of the obligate air-breathing pirarucu (Arapaima gigas) that starts life as water-breathing hatchlings. Contrasting with previous electrophoresis studies that report one or two isoHbs in adults, isoelectric focusing (IEF) resolved the hemolysates from both stages into four major bands, which exhibited identical O-2 binding properties (i.e. O-2 affinities, cooperativity coefficients, and sensitivities to pH and the major organic phosphate effectors), also as compared to the cofactor-free hemolysates. Of note, the multiplicity pattern recurred upon reanalyses of the most-abundant fractions iso-lated from the juvenile and the adult stages, suggesting possible stabilization of different quaternary states with different isoelectric points during the purification procedure. The study demonstrates unchanged Hb-O-2 binding properties during development, despite the pronounced differences in O-2 availability between the two media, which harmonizes with findings based on a broader spectrum of interspecific comparisons. Taken together, these results disclose that obligate air-breathing in Arapaima is not contingent upon changes in Hb multiplicity and O-2 binding characteristics.

The development of a continuous‐flow protocol for a palladium‐catalyzed methoxycarbonylation of (hetero)aryl chlorides using carbon monoxide gas and methanol is described. (Hetero)aryl chlorides are the least expensive of the aryl halides, but are underutilized in carbonylation reactions due to their very poor reactivity. The described protocol exploits intensified conditions at elevated temperature and pressure, which are readily accessed within a continuous‐flow environment, to provide moderate to excellent product yields (11 examples) in a short 16 min residence time. The continuous‐flow protocol enables the safe and potentially scalable carbonylation of aryl chlorides using CO gas., Continuous‐flow Pd‐catalyzed carbonylation of aryl chlorides with carbon monoxide at elevated temperature and pressure @KappeLab @RCPE @UniGraz @JanssenGlobal

Measuring mass mixing in batch reactors is of great interest to prevent yield losses during scale-up of reactions. In this work, we present a novel tool to accomplish this: the heat pulse method. This is a thermal-based technique consisting of a local heat pulse, applied electrically or by a hot liquid injection, during 10 s at a power of 5-15 W and subsequent measurement of temperature increase at locations of interest. The 95% mixing time from corrected and smoothed temperature profile characterizes heat mixing. A heat mixing model identifies the contributions of thermal conduction and convection and hereby relates local heat and mass mixing in a 800 mL in a 1 L batch reactor with a 45 degrees 4 blade downward pitched turbine. The heat pulse method is applicable on different reactors, solvent independent and non-destructive. Experiments are repeatable and mixing at reactive circumstances can be mimicked. (C) 2020 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

Knowledge and control of mixing in batch processes can prevent yield losses during scale-up. Therefore, in this study, a new heat-mixing model based ono the measurement of the heat distribution after an applied heat pulse, is proposed. The model was developed to predict mesomixing and support scale-up, scale-down, and design and optimisation of batch reactors. The proposed model considers the influences of rotational speed, stirrer type, solvent, stirrer-to-tank diameter, liquid-height-to-tank diameter, injection time, and pumping number. A strong correlation between the mixing time of the heat pulse method and the mass-transfer coefficient of the mixing-sensitive Bechamp reaction was observed.

Microspatially offset Raman spectroscopy (micro-SORS) has been proposed as a valuable approach to sample molecular information from layers that are covered by a turbid (nontransparent) layer. However, when large magnifications are involved, the approach is not straightforward, as spatial constraints exist to position the laser beam and the objective lens with the external beam delivery or, with internal beam delivery, the maximum spatial offset achievable is restricted. To overcome these limitations, we propose here a prototype of a new micro-SORS sensor, which uses bare glass fibers to transfer the laser radiation to the sample and to collect the Raman signal from a spatially offset zone to the Raman spectrometer. The concept also renders itself amenable to remote delivery and to the miniaturization of the probe head which could be beneficial for special applications, e.g., where access to sample areas is restricted. The basic applicability of this approach was demonstrated by studying several layered structure systems. Apart from proving the feasibility of the technique, also, practical aspects of the use of the prototype sensor are discussed.

In the framework of the inter-disciplinary KongoKing project, a set of beads from archaeological excavations in the Democratic Republic of the Congo was analysed by means of a minimally invasive, multi-analytical approach based on micro-Raman spectroscopy. The full characterization of the materials, including glassy network, opacifiers and colorizers, was achieved thanks to the combination of data from handheld X-ray fluorescence, variable pressure scanning electron microscopy coupled with energy-dispersive X-ray spectrometry, micro-Fourier transform infrared spectroscopy and pyrolysis coupled to gas chromatography and mass spectrometry. The obtained chemical information was used to fill the existing gap in the chemical study of beads from Western Central Africa. The cobalt-rich blue beads were found to be of Central European origin, while the copper-rich turquoise beads were manufactured using distinct copper sources. Cadmium yellow and cadmium red are the colourants responsible for the bright colours of bead types 10 and 12, respectively. The type 12 beads were found to be composed of glass covered with a waxy layer tentatively identified as Japan wax. Prosser-moulded bead type 9 was coloured by means of a chrome–tin pigment, while a combination of Mn and Fe is responsible for the black colour of the type 47 beads. Cuprite is most likely responsible for the red hue of glass layers from type 14. The dark palm green exterior of the type 17 bead was produced by using a combination of Cu and Fe compounds; iron was the only chromophore detected in the Indian red decoration. Copyright © 2017 John Wiley & Sons, Ltd.

Portable Raman spectroscopy is applied for the first time on rock art paintings from hunter-gatherers in three different provinces in Patagonia, Argentina (Neuquen, Rio Negro and Chubut). Selected archaeological sites were examined, revealing the local ‘palette’ of the native population and, if possible, the technology used. Moreover, alteration products were investigated to obtain valuable information for a better conservation and preservation of these magnificent rock art paintings. During a single research campaign, 16 shelters and one cave were investigated, which makes this study as one of the most condensed expeditions on measuring rock art paintings. Here, we evaluate the use of our portable Raman instrument to analyse rock art paintings under extreme conditions in Patagonia, Argentina. Several improvements are proposed to maximize the quality of the research output in such condensed expeditions. Copyright © 2017 John Wiley & Sons, Ltd.

Defocusing micro-spatially offset Raman spectroscopy (micro-SORS) is a recently developed technique that was proven to be successful in cultural heritage research to investigate non-destructively the stratigraphy of turbid or semi-transparent paint layers. However, until now this approach has not been applied to obtain imaging information with inhomogeneous real samples. In this work, a defocusing micro-SORS mapping approach is demonstrated with a 19th century porcelain card as a tool to study inhomogeneous painted stratigraphies; the depth information obtained with averaged defocusing sequences was combined with the lateral and spatial distribution achieved by mapping the painted zones. The effectiveness of the technique was verified by analysing an area where a partial overlapping of red (vermilion), blue (Prussian blue), green (chrome yellow and Prussian blue), and brown (vermillion and carbon black) pigmented zones is present, on top of a white (lead white) preparation layer.

The Archaeological Collection of Ghent University Museum hosts one of the most remarkable cork models representing the Pantheon of Rome, made by the master Antonio Chichi (1743-1816). Ghent University started a restoration campaign dedicated to the cork masterpiece, which has great artistic value. Next to macroscopic analysis, an extensive physicochemical campaign was organised in order to study and document the composition and the preservation state of the polychromic layers of Chichi’s masterpiece. Portable and micro-Raman spectroscopy revealed the presence of materials such as carbon-based pigments, lead white, vermilion, chalk, gypsum, bassanite, Prussian blue and haematite on the exterior and interior of the cork model. A tin-containing layer was characterized on the exterior of the model. XRF instruments were employed to better understand the overall elemental composition of the model’s polychromic layers, positively identifying Pb, Sn, Zn, Ca, Hg, Fe at the exterior surface. Stratigraphic analysis was performed, with both analytical techniques, when possible. The detailed information provided by archaeology, art history and applied sciences on the cork model of the Pantheon, will help the conservators to better understand and restore the Pantheon model which will be exhibited in the new museum of Ghent University.

Aims: Structural and functional characterization of the globin coupled sensors (GCS) of Azotobacter vinelandii (AvGReg) and Bordetella pertussis (BpeGReg). Results: UV/Vis and RR spectroscopies confirm the presence in AvGReg and BpeGReg of a globin domain capable of reversible gaseous ligand binding. In AvGReg an influence of the transmitter domain on the heme proximal region of the globin domain can be seen, and k'CO is higher than for other GCSs. The O2 binding kinetics suggest the presence of an open and a closed conformation. As for BpeGReg, the fully oxygenated AvGReg show a very high DGC activity. The CO rebinding to BpeGReg indicates that intra- and intermolecular interactions influence the ligand binding. The globin domains of both proteins (AvGReg-Gb and BpeGreg-Gb*) share the same GCS fold, a similar proximal but a different distal side structure. They homodimerize through a G-H helical bundle as in other GCS. However, BpeGReg-Gb* shows also a second dimerization mode. Innovation: This paper extends our knowledge on the GCS proteins and contributes to a better understanding of the GCSs' role in the formation of bacterial biofilms. Conclusions: AvGReg and BpeGreg conform to the GCS family, share a similar overall structure but they have different properties in terms of the ligand binding. In particular, AvGreg shows an open and closed conformation that in the latter form will very tightly bind oxygen. BpeGReg has only one closed conformation. In both proteins, it is the fully oxygenated GCS form that catalyzes the production of the second messenger.

Raman spectroscopy is a powerful technique for the characterization of materials and is of valuable use in archaeometrical research in general. Green compounds of natural or synthetic origin are found in many research areas, ranging from mineralogy, to pigment identification, to corrosion studies. However, a detailed and comprehensive database of spectra and references is still missing in the literature. This paper provides both, a literature review and downloadable Raman spectra of reference products, to the researcher dealing with green materials in cultural heritage. Moreover, it tackles nomenclature issues. The collected spectra are discussed in relation to the preliminary/commercial identification of the material itself and to the published data. Practical aspects regarding the laser wavelength selection are also discussed with regards to the comparison to published reference spectra. The range of studied green materials is wide and encompasses Cu containing compounds (natural and synthetic, more or less known as pigments or degradation products, including polymorphs of the same formula), Fe based (green earths and synthetic organic pigments), modern Cr and Co green pigments. This approach is illustrated by analysing a cross section of a green zone of the Early Netherlandish panel painting ‘Ghent Altarpiece’ by the Van Eyck brothers. Copyright © 2016 John Wiley & Sons, Ltd.

Only recently it was discovered that haemoglobin (Hb) belongs to the standard gene repertoire of insects, although their tracheal system is used for respiration. A classical oxygen-carrying function of Hb is only obvious for hexapods living in hypoxic environments. In other insect species, including the common fruit fly Drosophila melanogaster, the physiological role of Hb is yet unclear. Here, we study recombinant haemoglobin from the European honeybee Apis mellifera (Ame) and the malaria mosquito Anopheles gambiae (Aga). Spectroscopic evidence shows that both proteins can be classified as hexacoordinate Hbs with a strong affinity for the distal histidine. AgaHb1 is proposed to play a role in oxygen transport or sensing based on its multimeric state, slow autoxidation, and small but significant amount of five-coordinated haem in the deoxy ferrous form. AmeHb appears to behave more like vertebrate neuroglobin with a complex function given its diversified distribution in the genome.

A collection of glass beads found in Lumbu (Mbanza Kongo, Angola) were analyzed by means of a multi-analytical minimally invasive methodology, which included handheld X-ray fluorescence (hXRF), variable pressure scanning electron microscope coupled with energy dispersive X-ray spectrometry (VP-SEM-EDS), micro-Raman spectroscopy and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Trace element analysis, and rare earth element pattern analysis in particular, was found to be essential to establish the provenance of the European trade beads in this study. The glass beads from types 30, 31, 32, 36, 38, 39, 40, 41, 42, 43 and 45 were found to have been produced in Venice, and the glass beads from types 26 and 28 have been assigned to the Bohemian glass industry. While determining the provenance of each glass artefact was a major goal of this study, the process of glass coloring and opacification was also studied in an attempt to establish the technology employed in the production of these artefacts. Chemical data indicate that cobalt and copper were used to produce blue hues, while a combination of copper and iron ions was used to produce green glass. Black colored glass was obtained by the combined use of iron and manganese ions, whereas the iron-sulfur chromophore was used to impart a distinct amber hue to the glass. Red was produced using trace amounts of metallic gold particles (ruby red glass) and metallic copper nano-particles or cuprous oxide (brownish-red glass). Lead arsenates, calcium phosphate, and cassiterite were used as opacifying agents. The use of both morphological and chemical analysis enabled the identification of distinct European production centers, allowing a glimpse into the consumption patterns and economic interactions in place between Europe and West-Central Africa throughout the 17th-19th centuries.

An extensive in situ Raman spectroscopic campaign was performed on archaeological sites in three different provinces in Patagonia, Argentina (Neuquén, Río Negro and Chubut). 16 open air shelters located in different environments (forests, ecotones, steppes) were investigated and interpreted in terms of pigments used and the identification of substrata. Special attention was given to the alteration products and accretions that were found on the rock art paintings of the shelters and on the surface of the rock walls, as they can affect and damage this magnificent works of art. Haematite (α-Fe2O3) was the main chromophore that was found on the red paintings of the most of the shelters studied. The green earth glauconite, was identified only in one case, by using a red (785 nm) and a green laser (532 nm). Other minerals and silicates were found on the coloured areas but also on the rock support. Calcite (CaCO3) and gypsum (CaSO4 • 2H2O) crystallization was identified on the paintings, crusts and rock surfaces, in combination or alone, and are associated with weathering. In some cases the shelters were so severely degraded that no Raman signal of pigments and/or other components could be retrieved. Calcium oxalates were also detected in several figures and motifs in different shelters. Fil: Rousaki, Anastasia. University of Ghent; Bélgica Fil: Vargas, Fernando Emmanuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Diversidad Cultural y Procesos de Cambio. Universidad Nacional de Río Negro. Instituto de Investigaciones en Diversidad Cultural y Procesos de Cambio; Argentina Fil: Vázquez, Cristina. Comisión Nacional de Energía Atómica; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería; Argentina Fil: Aldazabal, Veronica Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Multidisciplinario de Historia y Ciencias Humanas; Argentina Fil: Bellelli, Cristina Teresa. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Secretaría de Cultura de la Nación. Dirección Nacional de Cultura y Museos. Instituto Nacional de Antropología y Pensamiento Latinoamericano; Argentina Fil: Carballido Calatayud, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Secretaría de Cultura de la Nación. Dirección Nacional de Cultura y Museos. Instituto Nacional de Antropología y Pensamiento Latinoamericano; Argentina. Universidad de Buenos Aires; Argentina Fil: Hajduk, Adam. Administración de Parques Nacionales. Museo de la Patagonia "Francisco Perito Moreno"; Argentina Fil: Palacios, Oscar Martín. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería; Argentina Fil: Moens, Luc. University of Ghent; Bélgica Fil: Vandenabeele, Peter. University of Ghent; Bélgica

Archaeometry is the research area on the edge between humanities and natural sciences: it uses and optimises methods from chemistry, spectroscopy, physics, biology, etc. to help answering research questions from humanities. In general, these objects are investigated for several reasons. Besides the fundamental interest to know about the materials that were used in the past, the study of artefacts can support their preservation, either by helping to select optimal storage or display conditions, either by investigating decay pathways and suggesting solutions. Other reasons for art analysis include provenance studies, dating the artefact or identifying forgeries. Since several years, Raman spectroscopy is increasingly applied for the investigation of objects of art or archaeology. The technique is well-appreciated for the limited (or even absent) sample preparation, the relative straightforward interpretation of the spectra (by fingerprinting - comparing them against a database of reference pigments) and its speed of analysis. Moreover, the small spectral footprint – allowing to record a molecular spectrum of particles down to 1 µm, the typical size of pigment grains – is certainly a positive property of the technique. Raman spectroscopy can be considered as rather versatile, as inorganic as well as organic materials can be studied, and as the technique can gather information on crystalline as well as on non-crystalline phases. As a consequence, Raman spectroscopy can be used to study antique objects and twentieth-century synthetic (organic) materials – illustrating the wide range of applications. Finally, the technique is as non-destructive, provided the laser power is kept sufficiently low not to damage the artwork. In literature, the terms “non-invasive” and “non-destructive” are used, where the first term means that no sampling is involved, and the latter term indicates that no sample is taken or that during analysis the sample is not consumed (destroyed) and remains available for further analysis.

Pigments and colourants are materials that have an enormous impact on how artworks are appreciated. Therefore, it is no surprise that since the first applications of Raman spectroscopy in art analysis, the study of this group of materials has gained special attention. Whereas the first applications often involved the identification of (mostly inorganic) pigments, the field has broadened towards the analysis of organic materials, such as synthetic pigments. Moreover, the study of dyes has gained from the developments in surface-enhanced Raman spectroscopy (SERS). Moreover, recently micro-spatially offset Raman spectroscopy (micro-SORS) was developed as a promising technique to study layered structures, such as paint layers.

Using the case of the Ghent University and its Technology Park, we will illustrate how changing policies and practices at the level of the university concerning research valorization have an impact on our science park. We will also demonstrate how the evolving nature of our science park has a clear impact on the university, as the science park becomes more and more an integral part of the university knowledge eco-system. We will also highlight the involvement of Ghent University in the Korea Songdo Global University Campus Project.

In Northwestern Patagonia, many archaeological sites can be found that testify human occupation by hunter–gatherer groups during the Holocene period. The general purpose of archaeological research in this area is to obtain information on the movements of these groups between the dry steppe and the different sectors in the forests. This paper reports on the results of the first spectroscopic analysis of samples from the archaeological excavation of two hunter–gatherer regions in Northern Patagonia (Traful Lake and Manso River areas). Thirty samples of rock art fragments, grinding tools, shell, raw pigment material, as well as painted ceramics and beads were examined with micro-Raman spectroscopy, complemented with X-ray fluorescence (XRF) analysis. Micro-Raman analysis revealed mostly the use of haematite (Fe2O3) as the red chromophore. The presence of associated minerals and silicates indicated that clay-like material (ochre) was used, instead of pure haematite. Although not fully conclusive, Raman spectroscopic results tend to indicate that in some samples haematite might be formed by heating iron-containing ochres. Copyright © 2015 John Wiley & Sons, Ltd.

Raman spectroscopic studies of carbonaceous materials are, until now, mainly devoted to geological and industrial materials. On the other hand, it is known from artistic literature that many varieties of carbon-based black pigments were produced and used in different places and times, and according to the artist’s preferences. The ability of Raman spectroscopy to analyse particles down to 1 μm and its non-destructiveness make it an ideal tool for pigments investigation. Anyway, the discrimination among different types of carbon-based black pigments is affected by various aspects, one of which is the lack of reference spectra as well as of specific nomenclature. In this paper, reference materials have been studied by means of Raman spectroscopy to provide reference spectra. All the pigments showed two broad bands of carbon, but sometimes specific excitation conditions were required to record a good quality Raman spectrum. The obtained Raman signatures are discussed, on the basis of the specificities of the pigment (natural or artificial origin; structural implications related to the raw materials used or to production processes; etc.). Therefore, on the basis of the Raman spectra of painting materials, further knowledge can be obtained on the type of carbon-based black pigments in works of art. Copyright © 2015 John Wiley &S ons, Ltd.