Light Transmission Analysis Research Articles

Stability and durability assessment of alum-tawed skin by light transmission analysis

Alum-tawed skin has been widely used in the past for the production of bookbindings elements because of its physical–mechanical properties and production process, easier and faster than that required for leather. Nevertheless, unlike for other skin-based materials employed in books production, such as parchment and leather, for alum-tawed skin the manufacturing process appears to be less standardized and rather few data are available in the literature on its durability and sensitivity to deterioration.In this work, a number of commercial samples of alum-tawed skin, from different manufactures and belonging to different animal species, were analysed by Light Transmission Analysis (LTA) to characterize their collagen hydrothermal stability, so as to gather useful information regarding their possible use for restoration works. The samples were then subjected to an artificial ageing process to assess their possible long term stability compared with that of some historical samples coming from 14th, 15th and 16th century bindings.The obtained results show that, as expected, the treatments the investigated alum-tawed skin samples undergo during the manufacture processes does not induce a level of stability of the collagen molecules higher than that of the vegetable and chrome tanning used for the leather treatment, although such treatment, in some cases, makes the alum-tawed skin slightly more stable than parchment. Moreover, accelerated ageing analysis showed that whatever the initial stability of the analysed samples, it decreases with ageing more rapidly and markedly than for parchment and leather, revealing a general lower durability of the alum-tawed skin to hydrothermal deterioration.

Deterioration effects of X-ray irradiation in artificially aged parchment

The effects of X-ray irradiation, a potential disinfection method, produced in parchment samples with different extent of artificial ageing have been investigated to analyse the possible superposition effects of the irradiation-induced damage with the existing ageing associated deterioration. The study was carried out in modern parchment samples in which different degrees of artificial ageing were induced by exposing them to severe hygro-thermal conditions for various durations. The aged samples were subsequently irradiated with increasing X-ray doses (350–4000 Gy). The consequent deterioration effects were analysed using light transmission analysis (LTA), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and fibre optic reflectance spectroscopy (FORS) in order to evaluate possible changes in, respectively, the hydro-thermal stability, the collagen protein structure (hydrolysis/denaturation) and the optical absorption/reflectance properties of the collagen protein. The results show increasing additional deterioration with irradiation dose for non-aged and moderately aged parchment, until damage saturation occurs for more intensively aged samples where no substantial additional deterioration is induced by the irradiation. The combined results indicate that the ageing produces the more substantial deterioration with respect to that induced by the irradiation treatment employed for disinfection purpose.

Evaluation of the Irradiation Treatment Effects on Ancient Parchment Samples

In this work, the effect of X-ray irradiation as a disinfection treatment in original ancient parchment samples, belonging to a discarded book cover of a 16th-century archival register, has been evaluated. Specifically, the bacterial and fungal species isolated from the book cover have been characterized and then irradiated with increasing doses of X-rays with the aim to evaluate the effectiveness of the antimicrobial protocol on the isolated microorganisms. The deterioration effects induced by the X-ray treatment as well as the natural aging on the collagen matrix of the parchment sample have been tested by employing several techniques, namely, Light Transmission Analysis, Fiber Optic Reflectance Spectroscopy, Attenuated Total Reflectance-Fourier Transformed Infrared spectroscopy, UV Resonant Raman spectroscopy and Atomic Force Microscopy. The results reveal that the irradiation treatment applied to our ancient parchment samples deteriorated by biological attack and other naturally occurring phenomena, possibly associated with inappropriate conservation conditions, does not seem to induce further damage factors even when large doses of irradiation are employed. The X-rays-based disinfection treatment effects are limited on the collagen support and this confirms the potential of this method in mass disinfection of library and archival materials.

Determination of the Dielectric Constant of CuSO4.5H2O (%) Solutions using Visible Light

Optical constants such as refractive index, absorption coefficient, extinction coefficient and the real (εr) and imaginary (εi) components of the dielectric constant for CuSO4.5H2O (10-100%) concentrations were determined from the visible light Optical transmission data. Results of visible light transmission analysis in the solutions have shown that in dilute solutions the dielectric constant real and imaginary parts are linear. The addition of dissolved cu+2 and so4-2 ions above (80%) concentrations results in a drop in dielectric constant.

Nanodiamond composites: A new material for the preservation of parchment

AbstractIn this work, the application of nanodiamond (ND)‐composites and dispersions as consolidating agents for parchment substrates has been studied. Different nanocomposites and ND‐based dispersions have been tested showing very promising results and making ND a potential high‐performance additive in the field of restoration. The effect of ND treatment on parchment has been evaluated by analyzing the variations in the parchment denaturation temperature, with respect to the untreated samples, by means of the Light Transmission Analysis (LTA), before and after artificial aging. The hydrolysis/gelatinization degree of the collagen molecule has also been analyzed by means of the Attenuated Total Reflection Fourier Transform IR (FTIR‐ATR) spectroscopy on the same samples investigated by LTA. ND composites, at certain concentrations, seem to improve the structural stability of the collagen networking, contrasting the thermo‐hygrometrically induced aging. Therefore, ND has confirmed to be a promising material to be applied for the restoration and conservation of Cultural Heritage.

Effect of X-ray and artificial aging on parchment

In this study, the employment of the X-ray irradiation as bioremediation method to treat parchment has been deeply investigated. In particular, the effect of the irradiation doses on the structural stability of collagen, the main constituent of parchment, has been evaluated on a series of modern parchment samples by means of different opto-thermal and spectroscopic techniques in order to obtain the dose-dependent effect of irradiation on collagen. Moreover, the long-term behavior of the irradiated parchment has been considered by analyzing the same series of samples after being hygrothermally artificially aged. Characterizations by light transmission analysis, Fourier transform infrared spectroscopy and the ultraviolet–visible–near infrared (UV–Vis–NIR) reflectance one have been performed for the identification of the radio-induced effect on the parchment structure even in a dose range much wider than the need for sterilization. The obtained results have proved the safeness of the method in the short and long term confirming the applicability of this emerging procedure.

The Integration of Metagenomics and Chemical Physical Techniques Biodecoded the Buried Traces of the Biodeteriogens of Parchment Purple Spots.

Ancient parchments record an immense part of our cultural heritage, having been used as the main written support material for centuries. Parchment easily undergoes biodeterioration, whose main signs are the so-called purple spots, which often lead to detachment of the superficial written layer. Up to recent years, several studies have been analyzing damaged parchments from different world’s archives, trying to trace back the culprit of the purple spots. However, standard cultivation and early molecular techniques have been demonstrated to be unsuccessful, leading the parchment damage issue remaining unsolved for many years. Nowadays, some studies have explored the parchment biodeterioration dynamics by adopting a multidisciplinary approach combining standard microbiological methods with high-throughput molecular, chemical and physical techniques. This approach allowed an unprecedented level of knowledge on the complex dynamics of parchment biodeterioration. This mini review discusses the application of the combination of basic and high-throughput techniques to study historical parchments, highlighting the strengths and weaknesses of this approach. In particular, it focuses on how metagenomics has been paramount for the unequivocal identification of the microbial main actors of parchment biodeterioration and their dynamics, but also on how metagenomics may suffer the distortion inflict by the historical perspective on the analysis of ancient specimens. As a whole, this mini review aims to describe the scenario of information on parchment biodeterioration obtained so far by using the integration of metagenomic with recent chemical (Raman spectroscopy) and physical (Light Transmission Analysis) approaches, which might have key implications in the preservation of many ancient documents.

Effects of the Ionizing Radiation Disinfection Treatment on Historical Leather

Microorganisms often cause significant damage on historical objects. The archive or library materials 24 as well as textile or leather artifacts suffer serious attacks that need appropriate care treatments. 25 Several biocide processes have been implemented but often their application does not preserve the 26 material of the good. The objective of this work is the disinfection through ionizing radiation of 27 leather wallpaper from the museum building Palazzo Chigi in Ariccia (Rome, Italy). The controlled 28 sterilization treatments were carried out using X-ray beams to eliminate the microorganisms present 29 on the leather and maintaining unchanged the properties of the constituent material. Some fragments 30 of decorated leather wallpaper, dating back to the 1700s, were irradiated with X-rays up to 5000 Gy. 31 The amount of microorganisms was evaluated by microbiological analysis before and after X-ray 32 irradiation treatments to identify the dose that inhibits the bacterial load. It will be shown how the 33 results obtained by the application of different chemical-physical techniques (Scanning Electron 34 Microscopy, Fourier Transform Infrared spectroscopy and Light Transmission Analysis) have helped 35 in the evaluation of the impact of the X-rays on leather chemical and physical integrity.

Dispersion of different carbon-based nanofillers in aqueous suspension by polycarboxylate comb-type copolymers and their influence on the early age properties of cementitious matrices

The dispersion behaviour of different carbon-based nanofillers in deionized (DI) water was investigated in the study at hand by using polycarboxylates as surfactants. Carbon nanotubes (CNTs), carbon black (CB) and expanded graphite (EG) were firstly characterized in respect of their morphology. Subsequently, they were dispersed in DI water using two polycarboxylate (PCE) comb-type copolymers which differed in length of their chemical backbones. Optical microscopy and light transmission analysis during centrifugation disclosed a clear difference in the dispersibility among the nanofillers under investigation. Small CB particles showed excellent dispersion in DI water even with no surfactant. CNT was dispersed significantly better than EG, whereby the PCE with the longer backbone yielded better filler dispersion in both cases. After incorporating the carbon nanofillers into a cementitious matrix, interestingly, the highest compressive and flexural strengths at an early age were measured for the CNT samples with worse filler dispersion. This effect is explained by the role of the PCE and the aspect ratio of the carbon nanofiller, both of which determine the microstructure in the hardened cement-based matrix collaboratively.

Integrated adiabatic scanning calorimetry, light transmission and imaging analysis of collagen deterioration in parchment

The collagen denaturation process in several artificially aged modern parchment samples were studied by combining Adiabatic Scanning Calorimetry and Light Transmission Analysis investigations. It was found that the calorimetric evaluations enabled not only to confirm the previously reported specific heat results concerning the collagen denaturation peaks, but also to identify a novel broad feature most likely associated with additional transformations occurring once denaturation takes place. Moreover, the combination of the investigations by the two adopted techniques allowed to validate the Light Transmission Analysis as a novel simple method capable of recording the entire collagen denaturation temperature path of the analyzed samples. Finally, the polarization microscopy imaging, performed simultaneously with the optical transmission characterization, enabled to perform a direct correlation of the morphology changes of the parchment with the different stages of the collagen denaturation.

A wheat grain quantitative evaluation of vitreousness by light transmission analysis

Light transmission through wheat (T. aestivum L.) grain longitudinal cross sections of different thickness was used to study the endosperm microstructure and was shown to strictly follow a Beer-Lambert law allowing a non ambiguous quantification of the endosperm vitreousness. Therefore similar samples obtained from near-isogenic lines differing by hardness and grown in two distinct environments affecting their vitreousness were analyzed and confirmed the relationship between light transmission and the endosperm microstructure. In each sample, moreover analysis of light transmission within the different grain parts highlighted the greater compactness of the central endosperm cheeks in comparison with the distal and the proximal regions. These results helps a better understanding of the endosperm microstructure.

Light transmission analysis of laser scattering imaging and Monte Carlo simulation in apple issue

The light transmission characteristics in apple tissue were studied by using laser scattering imaging and Monte Carlo (MC) simulation methods. The optical parameters of apple tissue were analyzed by laser scattering visual inspection system, and the scattering coefficient and absorption coefficient were obtained by least-square fitting method. MC method was used to simulate the light transmission of intact apple tissue. The results of MC simulation and laser scattering imaging experiments showed that the maximum error of diffuse reflectance at different locations did not exceed 3%. The internal quality of fruit is closely related to the absorption coefficient and scattering coefficient of light. The studying of the apple issue light transmission characteristics and MC simulation can help design the more effective and nondestructive detection system for fruit internal quality.

Protein aggregation studied by forward light scattering and light transmission analysis

The aggregation of the circadian blue-light photo-receptor cryptochrome from Drosophila melanogaster (dCry) is studied by transmission and forward light scattering measurement in the protein transparent wavelength region. The light scattering in forward direction is caused by Rayleigh scattering which is proportional to the degree of aggregation. The light transmission through the samples in the transparent region is reduced by Mie light scattering in all directions. It depends on the degree of aggregation and the monomer volume fill factor of the aggregates (less total scattering with decreasing monomer volume fill factor of protein globule) allowing a distinction between tightly packed protein aggregation (monomer volume fill factor 1) and loosely packed protein aggregation (monomer volume fill factor less than 1). An increase in aggregation with temperature, concentration, and blue-light exposure is observed. At a temperature of 4 °C and a protein concentration of less than 0.135 mM no dCry aggregation was observed, while at 24 °C and 0.327 mM gelation occurred (loosely packed aggregates occupying the whole solution volume).

Techniques for defining clarinet reed quality via computerized light transmission analysis.

A basic and well‐recognized problem in clarinet and saxophone (single‐reed) performance is maintaining consistency in high‐quality generation and manipulation of tones. This generative process, involving reed, mouthpiece, and the player’s embouchure, produces the instrumental ‘‘voice’’ of the performer and is fundamental to artistic communication. Playing skill and a well‐designed mouthpiece cannot overcome the liability of poorly vibrating arundo donax, the natural material used in reed manufacture. Inconsis‐ tency in quality leads professionals to spend as much as $2500 per year on reeds and to perform on relatively few of those purchased. Highly skilled performers agree that the identification of fine performance reeds cannot be accomplished by visual inspection. Trial by playing is the customary means of determining quality and one must purchase reeds before these trials can be made. Even these carefully selected reeds degrade and become unplayable after approximately 10–20 h of performance. Computerized light transmission analysis (TRACOR) has proven to be of value in determining performance characteristics of clarinet reeds.

Decreased adhesion of oxidized LDL-stimulated platelets caused by cytochalasin D

The adhesion of human blood platelets is studied with an in vitro model using reflection contrast microscopy and an image analysis system. The adhesive feature is promoted by oxidatively modified low density lipoprotein, which also induces functional morphological changes of platelets. However, when washed platelets are pretreated with 0.05 mM cytochalasin D, oxidized low density lipoprotein (100 micrograms/ml) causes a slower increase of the adhesion area (11.6 microns 2/min) compared to untreated platelets (15.7 microns 2/min) or platelets treated by oxidized low density lipoprotein alone (20.5 microns 2/min, P < 0.01). These results are supported by light transmission analysis and by transmission electron microscopy. Our experiments suggest that cytochalasin D inhibits the change of platelets in shape induced by oxidized low density lipoprotein, hinders the adhesion, but does not prevent the adhesion entirely.

Light transmission analysis of lymphocyte activation by mitogens: A new technique

In vitro lymphocyte transformation was evaluated by laser light transmission cytometry. Criteria are given for optimal application of this system to assessment of total cells and proportion of lymphoblasts in cultures. The light transmission studies revealed that cell numbers in mitogen stimulated cultures increase steadily, reaching a plateau. The percentage of lymphoblasts reached a peak after 4 days culture. The kinetics of [ 3H]-thymidine incorporation are similar. The increase in total cell number concomitant with decrease in [ 3H]thymidine incorporation at the fifth and sixth days indicates discordance between the cell proliferation and utilization of exogenous thymidine. The kinetics of total cell numbers and percentage of lymphoblasts suggest that in vitro reversion of lymphoblasts to small lymphocytes occurred. In addition to examining directly the cellular events during blastogenesis with ease, the current method appeared to be more reproducible than the [ 3H]thymidine incorporation assay.