Violin Varnishes: Microstructure and Nanomechanical Analysis.

The aim of the current work is twofold: to demonstrate the application of in situ non-invasive imaging by portable atomic force microscopy (AFM) on the surfaces of a violin and to integrate compositional and mechanical analysis at the nano scale level on model samples of varnished wood. These samples were prepared according to traditional recipes by an Italian lute-maker family well practised in the art. Samples of oil and spirit-based varnishes on maple wood, naturally and accelerated light aged, were studied.

Compromised dental cells viability following teeth-whitening exposure.

This study aimed to assess the viability of dental cells following time-dependent carbamide peroxide teeth-whitening treatments using an in-vitro dentin perfusion assay model. 30 teeth were exposed to 5% or 16% CP gel (4 h daily) for 2-weeks. The enamel organic content was measured with thermogravimetry.

Controlled Environment Neutron Radiography of Moisture Sorption/Desorption in Nanocellulose-Treated Cotton Painting Canvases.

Nanocellulose-based materials have recently been used to consolidate degraded cotton painting canvases. Canvas-supported paintings consist of materials that are sensitive to moisture and especially susceptible to environmental fluctuations in temperature and relative humidity (RH). These environmental fluctuations occur in uncontrolled environments found in historic houses and palaces and can lead to hydrolytic degradation and mechanical damage to canvases.

Influence of root maturity or periodontal involvement on dentinal collagen changes following NaOCl irrigation: an ex vivo study.

Aim: To refine a FTIR protocol for detection of NaOCl-induced dentinal collagen changes using an ex vivo irrigation model, and to apply it to determine the collagen change within 0.5 mm of canal or root surfaces, with or without mature roots or periodontal involvement.

Methodology: The root canals of extracted human roots were irrigated with control saline (n = 3) or 5% NaOCl (n = 3) and sectioned into transverse disks for FTIR analyses, 0.

Evaluation of the Adhesion and Performance of Natural Consolidants for Cotton Canvas Conservation.

Recent developments in paper and canvas conservation have seen the introduction of nanocellulose (NC) as a compatible treatment for the consolidation of historical cellulosic artifacts and manuscripts. However, as part of the assessment of these new materials for canvas consolidation, the adhesion of the consolidation treatment (which takes place between the applied material and the substrate) has not yet been evaluated, and as a result, it is poorly understood by both the scientific and conservation communities. After evaluating the potential of NC treatments for the consolidation of cotton painting canvas, we investigate a route to promote the interaction between the existing canvas and the nanocellulose treatment, which is in our case made of cellulose nanofibrils (CNF).

Proof-of-concept study to establish an in situ method to determine the nature and depth of collagen changes in dentine using Fourier Transform Infra-Red spectroscopy after sodium hypochlorite irrigation.

Aim: To establish a method using Fourier Transform Infra-Red spectroscopy (FTIR) to characterize the nature and depth of changes in dentinal collagen following exposure to sodium hypochlorite (NaOCl) during root canal irrigation in an ex vivo model.

Methodology: Fourier Transform Infra-Red spectroscopy was used to assess the changes in dentinal collagen when the root canal was exposed to NaOCl. The changes in dentinal collagen caused by NaOCl irrigation of root canals in transverse sections of roots, at 0.

On the potential of using nanocellulose for consolidation of painting canvases.

Nanocellulose has been recently proposed as a novel consolidant for historical papers. Its use for painting canvas consolidation, however, remains unexplored. Here, we show for the first time how different nanocelluloses, namely mechanically isolated cellulose nanofibrils (CNF), carboxymethylated cellulose nanofibrils (CCNF) and cellulose nanocrystals (CNC), act as a bio-based alternative to synthetic resins and other conventional canvas consolidants.

Remote assessment of cultural heritage environments with wireless sensor array networks.

The logistics and cost of environmental monitoring can represent challenges for heritage managers, partly because of the sheer number of environmental parameters to consider. There is a need for a system, capable of monitoring the holistic impact of the environment on cultural materials while remaining relatively easy to use and providing remote access. This paper describes a dosimetric system based on piezoelectric quartz crystal technology.

Effects of photochemical riboflavin-mediated crosslinks on the physical properties of collagen constructs and fibrils.

The use of collagen scaffold in tissue engineering is on the rise, as modifications to mechanical properties are becoming more effective in strengthening constructs whilst preserving the natural biocompatibility. The combined technique of plastic compression and cross-linking is known to increase the mechanical strength of the collagen construct. Here, a modified protocol for engineering these collagen constructs is used to bring together a plastic compression method, combined with controlled photochemical crosslinking using riboflavin as a photoinitiator.

The role of organic and inorganic indoor pollutants in museum environments in the degradation of dammar varnish.

This paper investigates the effects of inorganic (NO(2) and O(3)) and volatile organic acid (acetic acid) pollutants on the degradation of dammar varnish in museum environments. Model paint varnish samples based on dammar resin were investigated by Gas Chromatography Mass Spectrometry (GC-MS), Dynamic Mechanical Analysis (DMA) and Atomic Force Microscopy (AFM). Dammar is a natural triterpenoid resin, commonly used as a paint varnish.

A sutureless aortic stent-graft based on a nitinol scaffold bonded to a compliant nanocomposite polymer is durable for 10 years in a simulated in vitro model.

Purpose: To physiologically test the durability of a sutureless aortic stent-graft based on nitinol bonded to polyhedral oligomeric silsesquioxane (POSS) and poly(carbonate-urea) urethane (PCU) for 10 years according to Food and Drug Administration guidelines.

Methods: Aortic stent-grafts (n = 4) were tested in 37°C distilled water using simulated in vivo hydrodynamic pulse loading. After 400 million cycles, surface topography was assessed by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy.

Thermal denaturation studies of collagen by microthermal analysis and atomic force microscopy.

The structural properties of collagen have been the subject of numerous studies over past decades, but with the arrival of new technologies, such as the atomic force microscope and related techniques, a new era of research has emerged. Using microthermal analysis, it is now possible to image samples as well as performing localized thermal measurements without damaging or destroying the sample itself. This technique was successfully applied to characterize the thermal response between native collagen fibrils and their denatured form, gelatin.

Characterisation of temperature-dependent phase transitions in 2,2-trimethylenedioxy-4,4,6,6-tetrachlorocyclotriphosphazene, N3P3Cl4[O(CH2)3O].

Background: The crystal structure of 2,2-trimethylenedioxy-4,4,6,6-tetrachlorocyclo triphosphazene has been determined at 120, 274 and 293 K. The result at 293 K confirms the room temperature Cmc2(1) structure, but at the lower temperatures the space group is Pna2(1). Nevertheless the basic structure remains the same, with only small displacements of the atoms, amounting to an average of 25 pm between 120 and 293 K.

Silsesquioxane nanocomposites as tissue implants.

Background: Silicone implants are being used increasingly worldwide, especially in breast augmentation procedures. The most common morbidity observed is capsular contracture, which occurs in 15 percent of cases. To overcome this problem, the authors have developed a novel nanocomposite based on polyhedral oligomeric silsesquioxane-poly(carbonate-urea)urethane (POSS-PCU) for use as tissue implants.

Analysis and optimization of the cationic lipid component of a lipid/peptide vector formulation for enhanced transfection in vitro and in vivo.

We have previously described a lipopolyplex formulation comprising a mixture of a cationic peptide with an integrin-targeting motif (K16GACRRETAWACG) and Lipofectin, a liposome consisting of DOTMA and DOPE in a 1:1 ratio. The high transfection efficiency of the mixture involved a synergistic interaction between the lipid/peptide components. The aim of this study was to substitute the lipid component of the lipopolyplex to optimize transfection further and to seek information on the structure-activity relationship of the lipids in the lipopolyplex.

Review paper: principles and applications of surface analytical techniques at the vascular interface.

Surface properties have been found to be one of the key parameters which cause degradation and of thrombogenicity in all polymers used in biomedical devices, thus signifying the importance and the necessity for quantitative and accurate characterization of the polymer surface itself as used in the construction of the device. The characterization techniques employed generally involve thermal and spectroscopic measurements, in which class the electrochemical investigations and scanning probe microscopies can also be included. Current hypotheses on the correlations that exist between surface parameters and hemocompatibility and degradation of polymers are examined herein, but concentrating on the field of clinically utilized polymeric materials as used within medical devices themselves.

Mineralised tissues as nanomaterials: analysis by atomic force microscopy.

Mineralised tissues, such as bone, consist of two material phases: collagen protein fibrils that form the structural models upon which the mineral, calcium hydroxyapatite, is subsequently deposited. Collagen and mineral are removed in a three-dimensional manner by osteoclasts during bone turnover in skeletal growth or repair, and matrix proteins are replaced by the synthetic activity of osteoblasts and then calcify. The resolution of atomic force microscopy and use of unmodified, fully calcified samples has enabled the imaging of the overall bone and dentine structure, including collagen and mineral phases.

The degradative resistance of polyhedral oligomeric silsesquioxane nanocore integrated polyurethanes: an in vitro study.

Polymer biostability is one of the critical parameters by which these materials are selected for use as biomedical devices. This is the major rationale for the use of polymers which are highly crystalline and stiff namely expanded polytetrafluoroethylene (ePTFE) and Dacron in particular, as arterial bypass grafts. While this is immaterial in high-flow states, it becomes critically important at lower flows with a greater need for more compliant vessels.

Evidence of a distinct lipid fraction in historical parchments: a potential role in degradation?

Parchment, a biologically based material obtained from the processed hides of animals such as cattle and sheep, has been used for millennia as a writing medium. Although numerous studies have concentrated on the structure and degradation of collagen within parchment, little attention has been paid to noncollagenous components, such as lipids. In this study, we present the results of biochemical and structural analyses of historical and newly manufactured parchment to examine the potential role that lipid plays in parchment stability.

Atomic force microscopy of collagen structure in bone and dentine revealed by osteoclastic resorption.

Mineralised tissues such as bone consist of two material phases: collagen protein fibrils, secreted by osteoblasts, form model structures for subsequent deposition of mineral, calcium hydroxyapatite. Collagen and mineral are removed in a three-dimensional manner by osteoclasts during bone turnover in skeletal growth or repair. Bone active drugs have recently been developed for skeletal diseases, and there is revived interest in changes in the structure of mineralised tissues seen in disease and upon treatment.

Thermo-mechanical analysis of a compliant poly(carbonate-urea)urethane after exposure to hydrolytic, oxidative, peroxidative and biological solutions.

Aims: To date, there is still a great need for a fully viable small diameter (< 6 mm) polymeric vascular graft. Currently in such low flow locations, non-elastic expanded polytetrafluoroethylene (ePTFE) is the best available but it is quite inferior to autologous saphenous vein since it fails due to intimal hyperplasia caused by compliance mismatch between the graft and elastic host artery. Recently, a novel compliant poly(carbonate-urea)urethane vascular graft whose trade name is MyoLink has been developed.

Microclimate monitoring of indoor environments using piezoelectric quartz crystal humidity sensors.

The aim of this paper is to describe indoor microclimate monitoring at two different locations, Sandham Memorial Chapel, in Hampshire, England, and the castle El Alcázar, in Segovia, Spain. Piezoelectric quartz crystal sensors with novel humidity sensitive poly(ethyleneimine) coatings and Pt resistance thermometers were used to measure the relative humidity (RH) and temperature gradients across one of the paintings of the British artist, Stanley Spencer, housed in Sandham Memorial Chapel. The measurement period extended from December 1997 to September 1998.