Gold Foil Research Articles

One-step fabrication of the novel electrochemical sensing platform for the ultrasensitive determination of Microcystin-LR

To ensure the safety of the natural ecosystem, it is critical to develop portable, easy-to-operate and environmentally friendly quantitative analytical electrodes for the determination of microcystin-LR (MC-LR) in environmental water. Herein, a simple, mask-free, and one-step method based on laser-induced graphene (LIG) technology is designed for the fabrication of (3D) graphene electrodes integrated with gold nanoparticles (AuNPs). The 3-electrode system with AuNPs-modified graphene was prepared directly by overlaying gold leaf on the polyimide (PI) film followed by patterned CO2 laser irradiation. The reference electrode region was then uniformly coated with Ag/AgCl paste, and the working electrode was functionalized with the aptamer through Au-S self-assembly and bonding to obtain a label-free MC-LR aptasensor. The developed MC-LR aptasensor has a detection limit of 0.053 pM and a linear range from 0.1 pM to 10 nM. Furthermore, the fabricated aptasensor presents good stability, reproducibility, specificity and detection in real samples. These sensors show great promise as a low-cost, simple and portable approve for label-free detection MC-LR in environmental samples.

C&EN talks with Suzie Sheehy, accelerator physicist

In her new book The Matter of Everything: How Curiosity, Physics and Improbable Experiments Changed the World , accelerator physicist and science communicator Suzie Sheehy connects the wonders of modern technology to the fundamental research of the past century that made it possible. Sheehy tells the stories of 12 classic experiments in physics that transformed our understanding of how the world works. Anyone who has taken an introductory chemistry course will be familiar with many of the early chapters’ experiments, such as how J. J. Thomson used cathode ray tubes to discover electrons and how Ernest Rutherford and his students revealed the existence of the atomic nucleus using gold foil. Later sections of the book describe the gargantuan instruments that enabled scientists to detect for the first time elusive particles at the heart of the standard model, such as the neutrino and the Higgs boson. Through each tale, The Matter

Degradation of Fourteenth-century Mordant Gilding Layers: Synchrotron-based Microfocus XRF, XRD, and XANES Analyses of Two Paintings by Pietro Lorenzetti

ABSTRACT Analyses of the degraded mordant gilding on two early fourteenth-century paintings by Pietro Lorenzetti were undertaken at the UK synchrotron facility Diamond Light Source. Previous studies revealed a complex orpiment-tinted mordant and its application for adhering two separate layers of silver and gold leaf and demonstrated degradation of the original materials. A new study involving synchrotron radiation (SR) microfocus X-ray fluorescence (µ-XRF) maps on cross-sections of the discolored mordant allowed imaging of the extent of migration of mobile As-Ag-S bearing species and provided ideal positions from which to collect microfocus X-ray absorption near edge structure (µ-XANES) maps of As, Ag, and S for oxidation state analysis. SR µ-XANES indicates that arsenolite (As2O3) is present throughout the mordant suggesting light-induced photooxidation of orpiment. Both As3+ (as oxide) and As5+ have been detected and these are known signs for orpiment degradation. SR microfocus X-ray diffraction (µ-XRD) was used to reveal the nature of altered phases in the mordant layer and identified the presence of acanthite Ag2S, xanthoconite Ag3AsS3, and arsenolite As2O3. The analysis confirmed that the darkening of the mordant is most probably caused by finely dispersed grey-colored Ag + -bearing acanthite particles (Ag2S). The results are discussed in the context of analysis of contemporary paintings and recent studies on the alteration of orpiment.

Experimental benchmark data for Monte Carlo simulated radiation effects of gold nanoparticles. Part I: Experiment and raw data analysis

Electron emission spectra of gold nanoparticles (AuNPs) after photon interaction were measured over the energy range between 50 eV and 9500 eV to provide reference data for Monte Carlo radiation-transport simulations. Experiments were performed with the HAXPES spectrometer at the PETRA III high-brilliance beamline P22 at DESY (Hamburg, Germany) for photon energies below and above each of the gold L-edges, that is, at 11.9 keV, 12.0 keV, 13.7 keV, 13.8 keV, 14.3 keV, and 14.4 keV. The study focused on a sample with gold nanoparticles with an average diameter of 11.0 nm on a thin carbon foil. Additional measurements were performed on a sample with 5.3 nm gold nanoparticles and on reference samples of gold and carbon foils. Further measurements were made to calibrate the photon flux monitor, to characterize the transmission function of the electron spectrometer, and to determine the size of the photon beam. This allowed the determination of the absolute values of the spectral particle radiance of secondary electrons per incident photon flux. The paper presents the experimental and raw data analysis procedures, reviews the data obtained for the nanoparticle samples, and discusses their limitations.

Experimental benchmark data for Monte Carlo simulated radiation effects of gold nanoparticles. Part II: comparison of measured and simulated electron spectra from gold nanofoils

Electron emission spectra of a thin gold foil after photon interaction were measured over the energy range between 50 eV and 9500 eV to provide reference data for Monte Carlo radiation-transport simulations. Experiments were performed with the HAXPES spectrometer at the PETRA III high-brilliance beamline P22 at DESY (Hamburg, Germany) for photon energies just below and above each of the gold L-edges, that is, at 11.9 keV, 12.0 keV, 13.7 keV, 13.8 keV, 14.3 keV, and 14.4 keV. The data were analyzed to obtain the absolute values of the particle radiance of the emitted electrons per incident photon flux. Simulations of the experiment were performed using the Penelope and Geant4 Monte Carlo radiation-transport codes. Comparison of the measured and simulated results shows good qualitative agreement. On an absolute scale, the experiments tend to produce higher electron radiance values at the lower photon energies studied as well as at the higher photon energies for electron energies below the energy of the Au L3 photoelectron. This is attributed to the linear polarization of the photon beam in the experiments, something which is not considered in the simulation codes.

Raman Investigations on the Frame of the Painting “White Man’s Buffalo” by the Artist Charles M. Russell

The present work was a part of pre conservation treatment investigation. Micro-Raman Spectroscopy has been used for the characterization of a specimen belonging to the frame of the Gilcrease Museum oil painting “White Man’s Buffalo” by the artist Charles M. Russell. The main components of the Van Dyck Brown pigment (VDK) such as hematite (Fe2O3), α-goethite (α-FeOOH), amorphous carbon, and humic substances were identified by using two different excitation sources (514 and 633 nm). Traces of hematite and intercalated barite (BaSO4) were found and could come from the Armenian Bole that is commonly used in the water gilding technique of gold leaf. The use of a protein-organic binding medium such as rabbit-skin glue was indicated.

Color and Light: A Hellenistic Terracotta Figurine of a Maenad from Myrina

During the Hellenistic period and under the growing influence of the art of painting, the polychromy of Greek terracotta figurines focused not only on an elaborate rendering of color, but also on the interplay of light and shadow. Some of the best-preserved examples clearly show the subtlety of such pictorial effects. Among them is a statuette of a standing Maenad, held in the collections of the National Archaeological Museum in Athens (inv. 5000). Dating back to 150–100 BCE, it is a high-quality testament to the sculptural, as well as pictorial, coroplastic production in the workshops of Myrina (Eolide, Turkey). Combining multi-scale examination, multi-spectral imaging and non-invasive spectroscopic investigations (XRF, FTIR, FORS), a scientific study of the artefact was carried out within the framework of the Pilina project, a collaborative research program between the Louvre, the C2RMF, the National Archaeological Museum and the French School in Athens. This article presents the main results of the study by discussing the color scheme, identification of some pigments and colorants (clays of the kaolinite group, ochres, cinnabar, Egyptian blue, an anthraquinone of plant origin, likely madder, gold leaf), and painting techniques aiming at achieving chiaroscuro effects.

Absorption of sulfur dioxide gas in moistened porous material on a suspended gold leaf electrochemical sensor

This work describes an unconventional voltammetric detection in a gas medium using a suspended electrode unit. A paper moistened with the supporting electrolyte is used to absorb the gas. This concept was demonstrated for the in-situ detection of SO2 gas to quantify sulfite residue in samples of frozen shrimp. The gas is generated by the acidification of an aqueous suspension of shrimp tissues. The porosity of facial tissue paper is employed to provide a liquid layer of supporting electrolyte for the operation of the gold leaf electrochemical sensor. The absorbed gas is also dissolved in this liquid layer. The gold leaf sensor is reusable by replacing the tissue disc and rinsing the electrodes with water. The electrochemical sensor does not require refrigeration or pre-conditioning as with commercial biosensors and is thus suitable for point-of-need purposes. Production of the gold leaf sensor is only ca. 0.2 USD per unit and can be used regularly for up to 3 months. The linear calibration range of spiked negative control shrimp samples is from 3 to 240 mg kg−1 SO2 for a 30 mL solution of an extract of 5.0 g homogenized defrosted shrimp. The limit of detection (3 ×SDintercept/slope) for spiked samples is 2 mg kg−1 SO2. This is the first electrochemical sensor in a gas medium exploiting the entrapment of electrolyte solution inside a porous substrate.

Parchment, Gilding, and God: Gold Leaf and Divine Connection in a Camaldolese Choir Book

Previous article No AccessParchment, Gilding, and God: Gold Leaf and Divine Connection in a Camaldolese Choir BookStephanie AzzarelloStephanie AzzarelloKunsthistorisches Institut in Florenz, Italy Search for more articles by this author PDFPDF PLUSFull Text Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmailPrint SectionsMoreDetailsFiguresReferencesCited by I Tatti Studies in the Italian Renaissance Volume 26, Number 1Spring 2023 Published for Villa I Tatti: The Harvard University Center for Italian Renaissance Studies Article DOIhttps://doi.org/10.1086/724251 © 2023 Villa I Tatti: The Harvard University Center for Italian Renaissance Studies. All rights reserved.PDF download Crossref reports no articles citing this article.

Simultaneous quantitative analysis of Escherichia coli, Staphylococcus aureus and Salmonella typhimurium using surface-enhanced Raman spectroscopy coupled with partial least squares regression and artificial neural networks

Simultaneous detection of mixed bacteria accurately and sensitively is a major challenge in microbial quality control field. In this study, we proposed a label-free SERS technique coupled with partial least squares regression (PLSR) and artificial neural networks (ANNs) for quantitative analysis of Escherichia coli, Staphylococcus aureus and Salmonella typhimurium simultaneously. SERS-active and reproducible Raman spectra can be acquired directly upon the bacteria and Au@Ag@SiO2 nanoparticle composites on the surface of gold foil substrates. After applying different preprocessing models, SERS-PLSR and SERS-ANNs quantitative analysis models were developed to map SERS spectra of concentrations of the Escherichia coli, Staphylococcus aureus and Salmonella typhimurium, respectively. Both models achieved high prediction accuracy and low prediction error, while the performance of SERS-ANNs model in both quality of fit (R2 > 0.95) and accuracy of predictions (RMSE < 0.06) was superior to SERS-PLSR model. Therefore, it is feasible to develop simultaneous quantitative analysis of mixed pathogenic bacteria by proposed SERS methodology.

Gold leaf tesserae: tracing the origins of gold using synchrotron-based techniques

Gold leaf tesserae: tracing the origins of gold using synchrotron-based techniques

Evaluating the stability of Ir single atom and Ru atomic cluster oxygen evolution reaction electrocatalysts

Single-atom catalysts (SACs) have recently emerged in electrocatalysis due to their improved electrocatalytic performance in many industrially relevant reactions. The potential application of SACs also includes oxygen evolution reaction (OER), where high anodic potentials and corrosive acidic environments narrow the choice of classical nanoparticulated electrocatalysts to scarce iridium (Ir) and ruthenium (Ru) noble metals. To date, published literature mainly focused on improving SACs activity or selectivity, while stability was rarely assessed using electrochemical methods and post-mortem characterizations. To fill this knowledge gap, we utilize an online inductively coupled plasma mass spectrometry setup (online ICP-MS) to evaluate the stability of Ir SAC and highly dispersed Ru catalysts supported by indium doped tin oxide (ITO) prepared via surface organometallic chemistry. After benchmarking with commercial IrO2 and RuO2 nanoparticulated catalysts, we validate their high activity and determine their lower stability, confirming the previously reported inverse activity-stability relationship. The observed lower stability is proposed to originate from a change in the OER mechanism from the adsorbate evolution mechanism (AEM) driven by the catalysts to the lattice oxygen mechanism (LOM) with participation of the support. This is confirmed by the increase in Tafel slope, coinciding with the dissolution onset of the ITO support. Additionally, we show that there is no effect of the commonly used backing electrodes (glassy carbon, gold foil, and boron-doped diamond) on the activity and stability. This work provides guidelines for evaluating highly dispersed atomic catalysts in future research and fundamental insights into the role of the support in their stability.

A universal approach for sensitive and rapid detection of different pathogenic bacteria based on aptasensor-assisted SERS technique.

An assembled-aptasensor based on Fe3O4@Au@Ag nanocomposites grafting onto the gold foil was prepared, which can be developed into a universal approach for sensitive and rapid detection of various pathogenic bacteria, such as Escherichia coli (E. coli), Salmonella typhimurium (S. typhimurium), Staphylococcus aureus (S. aureus), Listeria monocytogenes (L. monocytogenes), Pseudomonas aeruginosa (P. aeruginosa), and Shigella flexneri (S. flexneri). Firstly, the gold foil paper was modified with thiolated capture probe and SERS tag in proportion, and at the same time, the specific thiolated aptamer probe for corresponding pathogenic bacteria was fixed with Fe3O4@Au@Ag nanocomposites. An obvious Raman signal can be subsequently increased about 106 times by the external electromagnetic field enhancement at the "hot spots" caused by the hybridization of aptamer and capture probe. But in the presence of target pathogenic bacteria, Raman intensity will decrease as Fe3O4@Au@Ag nanocomposites are dissociated from gold foil. Thus, all of the concentrations of the six kinds of pathogenic bacteria both in PBS and liquorice extract showed an obvious negative linear correlation with the Raman intensity of SERS tag in the range of 10-107CFU/mL with detection limits were all lower than 10CFU/mL. And there was no significant difference between our method and the plate counting method. Besides, the assembled-aptasensor had superior specific recognition ability even in the mixed interfering bacteria. Our study showed that this assembled-aptasensor had good specific detection ability to a variety of foodborne pathogens based on magnetic field-assisted SERS technique, which can be used for rapid and sensitive detection of a variety of pathogens in complex substrates.

Research on Packaging Design of Cultural and Creative Products Derived from the Intangible Cultural Heritage of Gold Foil

With a focus on the development dilemma faced by the industry of gold foil as the intangible cultural heritage in China, the innovative packaging design is blended into the gold foil technology and the product design based on the cultural creation of the intangible cultural heritage to form a new model of packaging design of cultural and creative products. In light of the status quo and problems of packaging of cultural and creative products derived from gold foil in Nanjing, this study is to analyze the outstanding packaging design of cultural and creative products at home and abroad so as to extract the design methods that are locally applicable. Furthermore, this study aims to explore the innovation path of packaging design of cultural and creative products derived from gold foil in Nanjing through practice, and then to provide valuable reference for the establishment of national brands and the inheritance of skills.

Manufacture of Tl targets by electrodeposition for the study of excitation functions of 203Pb

Natural Tl targets were manufactured by electrochemical deposition on a foil gold backing. The electrochemical parameters were defined after several experiments and reverse pulse potential was chosen to avoid the formation of filaments and dendrites. Once these parameters were established, enriched 205Tl targets were manufactured on a gold foil backing to be used to measure the cross sections for 203Pb production by deuteron induced reactions. The production yield was calculated from our excitation functions and was found to be 54 MBq/µAh in the energy interval 32.5 MeV – 30 MeV.

History of gold filling in dentistry

Gold does not oxidize, it is difficult to transform it into a chemical compound, but its compounds can be reduced to colored gold extremely easily. It is the only metal that does not react with oxygen and sulfur even at high temperatures. Gold is the most popular metal in dentistry, for decorating, in fixed prosthodontics, for crowns, and inlays or gold foil restorations.

An Artificial Intelligence System for Automatic Recognition of Punches in Fourteenth-Century Panel Painting

In Late-Medieval panel paintings from the Tuscan area, mechanical tools called punches were used to impress repeated motifs on gold foils to create decorative patterns. Such patterns can be used as clues to objectively support the attribution of the paintings, as proposed by art historian Erling S. Skaug in his decades-long study on punches. We investigate the feasibility of employing automatic pattern recognition techniques for accelerating the process of classification of punches by experts working in the field. We propose a system composed of (a) a Convolutional Neural Network for categorizing a punch contained in a frame, and (b) an additional component for uncertainty estimation, aimed at recognizing possible Out-of-Distribution (OOD) samples. After collecting a set of 14th century panel paintings from Tuscany, we train a Convolutional Neural Network which achieves very high test-set accuracy. As far as the uncertainty estimation is concerned, we experiment with two techniques, OpenGAN and II-loss, both exhibiting very positive results. The former seems to work better on specific data extracted from images of panel paintings, while the latter showcases a more consistent behavior when considering additional OOD data obtained randomly. These outcomes indicate that an application of our system in support of experts is feasible, although we subsequently show that additional experiments on larger datasets might be required.

Recent advances in gold electrode fabrication for low-resource setting biosensing.

Gold electrodes are some of the most prevalent electrochemical biosensor substrate materials because they are readily functionalized with thiolated biomolecules. Yet, conventional methods to fabricate gold electrodes are costly and require onerous equipment, precluding them from implementation in low-resource settings (LRS). Recently, a number of alternative gold electrode fabrication methods have been developed to simplify and lower the cost of manufacturing. These methods include screen and inkjet printing as well as physical fabrication with common materials such as wire or gold leaf. All electrodes generated with these methods have successfully been functionalized with thiolated molecules, demonstrating their suitability for use in biosensors. Here, we detail recent advances in the fabrication, characterization and functionalization of these next-generation gold electrodes, with an emphasis on comparisons between cost and complexity with traditional cleanroom fabrication. We highlight gold leaf electrodes for their potential in LRS. This class of electrodes is anticipated to be broadly applicable beyond LRS due to their numerous inherent advantages.

Body-Worldings of Later Scandinavian Prehistory: Making Oddkin with Two Body-Objects

In the last two decades, the body has emerged as a rich field of theorization and scholarly exploration in archaeology. This paper is an excursion into a consideration of two bodyobjects of prehistoric Denmark: an anthropomorphic bronze figurine from the Fårdal assemblage dating to the late Bronze Age, and a figural gold foil with an anthropomorphic stamp from Sorte Muld, created perhaps as much as 1 500 years later, in the Merovingian period (550–750 CE). The two images are made in very different materials, in distinctly different forms, and belong to different historical situations. Nevertheless, the two artefacts render what are likely women’s bodies with clear differences, but also some uncanny similarities.This article explores these artefacts from a more-than-representational perspective. Moving beyond a taxonomic approach, it focuses on aspects of these images beyond what or who they ‘represent’. What can such an approach tell us about the capacities of bodies, as well as the capacities of the artefacts themselves? This entails, following the work of Donna Haraway, worlding them in two vastly different social, material and political worlds; drawing out their making from two very different technological processes; engaging with the similarities and differences of their biographies; and, crucially, thereby contemplating their kinship.

Pottery vessels from a collective burial in the mound of the Pazyryk Culture (Northern Altai)

In one of the barrows examined in 2007 at the site of Choburak-II (the territory of the Northern Altai), an in-trusive, and not quite ordinary, a collective burial of people was found. Accompanying burials of two horses were also recorded there and a variety of artefacts was found (a fragment of a stone grain grinder, elements of horse harness, miniature knives made of non-ferrous metal, a dagger, a chisel, a quiver hook, fragments of gold foil from clothing decoration and other items). The recovered materials made it possible to attribute the excavated burial site to the Pazyryk Culture and to carry out its dating, including the radiocarbon method. In this publication, a special attention is given to the pottery finds. Two vessels appeared to be severely damaged, and to determine their parameters it was necessary to use the bespoke technique of computer-aided restoration based on photo-grammetry and aimed at obtaining the most probable shape of these ancient containers. In this respect, an algo-rithm, being tested by the authors, of modern demonstration in publications of the category of products in question was implemented. Based on the reconstructions performed in the paper, the restored dimensions of the pottery vessels are given, as well as their closest analogies. The third pot (of a closed jar shape with well-marked han-dles) was found intact. It reflects a different cultural tradition. Such products are very rare in the Altai Mountains. However, they are found in the neighboring and somewhat remote territories. This circumstance influenced the in-terpretation of the recorded situation. Pottery ware is an important archaeological source. Unfortunately, it has not yet become a separate research area in the study of the Pazyryk Culture. It is hoped that the developments of the authors of the paper will contribute to the research. The specific nature of this additional burial of the deceased person is noted. The investigated archaeological site to a certain extent may reflect the processes of interaction of the Pazyryk popula-tion with their northern neighbors. The body of the considered data complements the content and features of the culture of the Altai population of the Scythian-Saka period.