Nanoscale Probing of the Organic Binder in Artists' Paint Layers: Organic Phases and Chemical Heterogeneity.

Understanding paint structures at the nanoscopic level can address key questions related to artistic techniques, paint formulation, and long-term preservation of artworks. This involves examining spatial chemical complexity, the formation of molecular networks, and interactions between organic and inorganic constituents. Depending on the paint preparation methods, proteins and drying oils, the most common binders in traditional artistic practices, can be integrated to produce paints with diverse structures and nanoscale chemical intricacies.

The role of early synthetic materials degradation in the downfall of the Ansaldo A.1, an Italian World War I biplane fighter.

From the Pioneer Era of the aviation to World War I the evolution of aircraft technology and chemical synthesis enabled a unique coexistence of traditional craftsmanship, artistic decoration practices, and technological advancements. The study of the materials used in these early years of aviation is still an uncharted territory: a vast portion of remaining planes has been partially or completely repaired and restored, usually by total replacement of the fabric. The Italian biplane Ansaldo A.

A versatile method to fingerprint and compare the oxidative behaviour of lipids beyond their oxidative stability.

In this work we propose the use of isothermal thermogravimetry to evaluate the oxidative stability of a lipid and to evaluate how the glyceride composition affects the entire oxidative process, to quantify the oxidation undertaken by the lipid, and numerically compare the oxidative behaviour of different lipids. The innovative aspect of the present method lies in the acquisition of a prolonged "oxygen uptake" curve (4000-10,000 min) of a lipid under oxygen and in the development of a semi-empirical fitting equation for the experimental data. This provides the induction period (oxidative stability), and allows to evaluate the rate of oxidation, the rate and the magnitude of oxidative degradation, the overall mass loss and the mass of oxygen taken by the lipid upon time.

A holistic view on the role of egg yolk in Old Masters' oil paints.

Old Masters like Botticelli used paints containing mixtures of oils and proteins, but "how" and "why" this was done is still not understood. Here, egg yolk is used in combination with two pigments to evaluate how different repartition of proteinaceous binder can be used to control the flow behavior as well as drying kinetics and chemistry of oil paints. Stiff paints enabling pronounced impasto can be achieved, but paint stiffening due to undesired uptake of humidity from the environment can also be suppressed, depending on proteinaceous binder distribution and colloidal paint microstructure.

Proteomic Characterization of Collagen-Based Animal Glues for Restoration.

Animal glues are widely used in restoration as adhesives, binders, and consolidants for organic and inorganic materials. Their variable performances are intrinsically linked to the adhesive properties of collagen, which determine the chemical, physical, and mechanical properties of the glue. We have molecularly characterized the protein components of a range of homemade and commercial glues using mass spectrometry techniques.

Disentangling the chemistry of Australian plant exudates from a unique historical collection.

For thousands of years, the unique physicochemical properties of plant exudates have defined uses in material culture and practical applications. Native Australian plant exudates, including resins, kinos, and gums, have been used and continue to be used by Aboriginal Australians for numerous technical and cultural purposes. A historic collection of well-preserved native Australian plant exudates, assembled a century ago by plant naturalists, gives a rare window into the history and chemical composition of these materials.

The stability of paintings and the molecular structure of the oil paint polymeric network.

A molecular-level understanding of the structure of the polymeric network formed upon the curing of air-drying artists' oil paints still represents a challenge. In this study we used a set of analytical methodologies classically employed for the characterisation of a paint film-based on infrared spectroscopy and mass spectrometry-in combination with solid state NMR (SSNMR), to characterise model paint layers which present different behaviours towards surface cleaning with water, a commonly applied procedure in art conservation. The study demonstrates, with the fundamental contribution of SSNMR, a relationship between the painting stability and the chemical structure of the polymeric network.

Short-term and long term morbidity in robotic pancreatic surgery: a systematic review.

Background: Pancreatic cancer is one of the most aggressive and lethal tumours in Western society. Pancreatic surgery can be considered a challenge for open and laparoscopic surgeons, even if the accuracy of gland dissection, due to the close relationship between pancreas, the portal vein, and mesenteric vessels, besides the reconstructive phase (in pancreaticoduodenectomy), lead to significant difficulties for laparoscopic technique. Minimally invasive pancreatic surgery changed utterly with the development of robotic surgery.

The using of sealants in pancreatic surgery: A Systematic Review.

Background: POPF derives from the pancreatic stump, which follows pancreatic resection and the pancreatoenteric anastomosis following pancreaticoduodenectomy. Since 1978 sealants have been used in pancreatic surgery to prevent pancreatic fistula after resection of the pancreatic head and tail or for the management of trauma and the treatment of low-output pancreatic fistula. Different types of fibrin sealants have been evaluated for their potential to reduce the occurrence of POPF.

A new anterior approach to parastomal hernia repair (PHR) with linear stapler suture: A case report.

Introduction: Parastomal hernia is a type of incisional hernia occurring in abdominal integuments in the vicinity of a stoma. The best surgical approach for PSH remains controversial. Most studies report short follow-up time after surgery and a low number of cases to allow conclusions.

Conservation Issues of Modern Oil Paintings: A Molecular Model on Paint Curing.

The 20th and 21st century oil paintings are presenting a range of challenging conservation problems that can be distinctly different from those noted in paintings from previous centuries. These include the formation of vulnerable surface "skins" of medium and exudates on paint surfaces, efflorescence, unpredictable water and solvent sensitivity, and incidence of paint dripping which can occur within a few years after the paintings were completed. Physicochemical studies of modern oil paints and paintings in recent years have identified a range of possible causal factors for the noted sensitivity of painting surfaces to water and protic solvents, including the formation of water-soluble inorganic salts and/or the accumulation of diacids at the paint surface, which are oxidation products of the oil binder.

On the influence of relative humidity on the oxidation and hydrolysis of fresh and aged oil paints.

Modern oil paintings are affected by conservation issues related to the oil paint formulations and to the fact that they are often unvarnished, and in direct contact with the environment. Understanding the evolution of the molecular composition of modern oil paint during ageing, under the influence of environmental factors, is fundamental for a better knowledge of degradation phenomena and risk factors affecting modern art. We investigated for the first time the influence of relative humidity on the chemical composition of modern oil paints during curing and artificial ageing.

The role of the polymeric network in the water sensitivity of modern oil paints.

Spectroscopic and mass spectrometric analytical techniques were used to characterise two naturally aged Winsor & Newton (W&N) Winsor Green (phthalocyanine green, PG7) artists' oil colour paint swatches dating to 1993 and 2003. Infrared and Energy Dispersive X-ray (EDX) analysis indicated that the swatches were of closely similar composition, yet the swatch from 2003 was water-sensitive whilst the swatch from 1993 was not. Water-sensitivity is a conservation challenge associated with significant numbers of modern oil paintings and this study aimed to further develop our understanding of the molecular causes of water sensitivity.

Evolved Gas Analysis-Mass Spectrometry to Identify the Earliest Organic Binder in Aegean Style Wall Paintings.

An organic binder was identified in the painted fragments from the Canaanite palace of Tel Kabri, Israel. Recently dated to the late 18th century B.C.

Characterization of Degraded Proteins in Paintings Using Bottom-Up Proteomic Approaches: New Strategies for Protein Digestion and Analysis of Data.

Chemical hydrolysis assisted by microwave irradiation has been proposed as an alternative method for the analysis of proteins in highly insoluble matrices. In this work, chemical hydrolysis was applied for the first time to detect degraded proteins from paintings and polychromies. To evaluate the performance of this approach, the number of identified peptides, protein sequence coverage (%), and PSMs were compared with those obtained using two trypsin-based proteomics procedures used for the analysis of samples from cultural heritage objects.

Recent Advances in Analytical Pyrolysis to Investigate Organic Materials in Heritage Science.

The molecular characterization of organic materials in samples from artworks and historical objects traditionally entailed qualitative and quantitative analyses by HPLC and GC. Today innovative approaches based on analytical pyrolysis enable samples to be analysed without any chemical pre-treatment. Pyrolysis, which is often considered as a screening technique, shows previously unexplored potential thanks to recent instrumental developments.

A novel HPLC-ESI-Q-ToF approach for the determination of fatty acids and acylglycerols in food samples.

We propose a new analytical method using reverse phase High performance liquid chromatography (HPLC) coupled through an electrospray source with a tandem quadrupole-time-of-flight (ESI-Q-ToF) mass spectrometric detector for the full characterization and quantitation of the different classes of fatty acids and acylglycerols in lipid samples in a single chromatographic run. In this work, we optimized the derivatization reaction for free fatty acids with 2-hydrazinoquinoline, which is a low-cost approach, using a full factorial design. This reaction does not involve transesterification, thus enabling the free fatty acids to be separated and successfully quantified in the presence of mono-, di- and triacylglycerols without altering the whole glyceride profile.

A molecular study of modern oil paintings: investigating the role of dicarboxylic acids in the water sensitivity of modern oil paints.

The 20th century has seen a significant evolution in artists' paint formulation and technology which is likely to relate to the new conservation challenges frequently presented by modern oil paintings, including unpredictable water- and solvent-sensitivity. This study examined the molecular causes and mechanisms behind these types of modern oil paint vulnerability. Research performed up to now has suggested a correlation between the occurrence of water sensitivity and the presence of relatively high amounts of extractable free dicarboxylic acids.

Development of a GC/MS method for the qualitative and quantitative analysis of mixtures of free fatty acids and metal soaps in paint samples.

In this paper we present a new analytical GC/MS method for the analysis of mixtures of free fatty acids and metal soaps in paint samples. This approach is based on the use of two different silylating agents: N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) and 1,1,1,3,3,3-hexamethyldisilazane (HMDS). Our experimentation demonstrated that HMDS does not silylate fatty acid carboxylates, so it can be used for the selective derivatization and GC/MS quantitative analysis of free fatty acids.

The characterisation of shellac resin by flow injection and liquid chromatography coupled with electrospray ionisation and mass spectrometry.

A strategy based on electrospray ionisation (ESI) in negative mode coupled with quadrupole-time of flight (Q-ToF) detection techniques was adopted to characterise some samples of shellac resin. Flow injection analysis (FIA) was used to investigate the distribution of the components of the resin. Eight groups of compounds with increasing masses were detected and assigned to free acids, esters and polyesters with up to eight units.

GC/MS and proteomics to unravel the painting history of the lost Giant Buddhas of Bāmiyān (Afghanistan).

A chemical investigation of the organic paint binders of the Giant Buddhas of Bāmiyān was performed using an analytical approach based on mass spectrometry, combining traditional gas chromatography/mass spectrometry protocols with advanced proteomics methodologies. The research was carried out on a selection of rescued fragments. The data revealed the use of egg proteins as the paint binders of the original layers, in accordance with the traditional use of this proteinaceous medium in antiquity, spanning from the Mediterranean basin to the Far East, and already in the Bronze Age.

Analytical Approaches Based on Gas Chromatography Mass Spectrometry (GC/MS) to Study Organic Materials in Artworks and Archaeological Objects.

Gas chromatography/mass spectrometry (GC/MS), after appropriate wet chemical sample pre-treatments or pyrolysis, is one of the most commonly adopted analytical techniques in the study of organic materials from cultural heritage objects. Organic materials in archaeological contexts, in classical art objects, or in modern and contemporary works of art may be the same or belong to the same classes, but can also vary considerably, often presenting different ageing pathways and chemical environments. This paper provides an overview of the literature published in the last 10 years on the research based on the use of GC/MS for the analysis of organic materials in artworks and archaeological objects.

Terpenoid Oligomers of Dammar Resin.

Dammar is a triterpenoid resin containing a volatile fraction, a monomeric fraction, and a high-molecular weight fraction. Although the low-molecular-weight components comprising sesquiterpenoids and triterpenoids have been extensively studied, the nature of the macromolecular components is still not fully understood, and different and sometimes contradictory theories have been proposed. The aim of this paper is to clarify the nature of the macromolecular components of dammar resin.

Deglycosylation Step to Improve the Identification of Egg Proteins in Art Samples.

A deglycosylation step using Peptide-N-Glycosidase F (PNGaseF) has been introduced in a standard proteomic protocol to more confidently identify egg based binders. The ingenuity of introducing a PNGaseF digestion was aimed at removing the molecular hindrance, made up by the heavily glycosylated egg proteins, before the protease(s) hydrolysis. This novelty in the protocol resulted in obtaining a significant increase of proteolytic egg peptides thus improving the quality and reliability of egg identification in artwork samples.