Adhesive Substance Research Articles

Morphology and glandular composition of the myzorhynchus and the remnant apical organ in adult cestodes of the order Rhinebothriidea from batoids off Argentina.

The main objective of this study was to analyze the function of the myzorhynchus and remnant apical organ of adult cestodes in the order Rhinebothriidea. Several features of these structures were analyzed in 12 species belonging to six genera and two families. In particular, the glandular composition of the myzorhynchus of four species from Echeneibothriidae (i.e., Notomegarhynchus navonae and three species of Echeneibothrium) was studied using histochemical techniques and/or transmission electron microscopy. In addition, the presence of a remnant apical organ and its glandular composition were analized in six species of Rhinebothriidae and in two species of Semiorbiseptum, whose familial assignment is uncertain. We also evaluated the importance of these characters for diagnosis. The same type of gland cell was found in the myzorhynchus of Echeneibothrium species and in the remnant apical organ of Semiorbiseptum species. These gland cells were Coomassie brilliant blue-positive, periodic acid Schiff-positive and Alcian blue-negative, consistent with a glycoprotein secretion possibly involved in adhesion to the host mucosa and proteolysis. The type of gland cells found in the myzorhynchus of N. navonae were Coomassie brilliant blue-negative, periodic acid Schiff-positive and Alcian blue-positive, consistent with the production of adhesive and protective substances. The type of gland cells in the myzorhynchus and in the remnant apical organ could be a useful character for the generic diagnosis of Echeneibothrium and Semiorbiseptum, respectively. A remnant apical organ was only found in Semiorbiseptum, with its presence/absence being important as a diagnostic character at the generic level for Semiorbiseptum, Scalithrium, and Rhinebothroides. A secondary objective was to characterize the microthrix pattern of the myzorhynchus of N. navonae. An extended distribution of spinitriches was detected, which may allow a better adhesion of this large species to the host mucosa, as the main function of spinitriches is presumably that of adhesion.

Production and use of birch bark tar at the Neolithic pile‐dwelling of Palù di Livenza (North‐Eastern Italy) revealed by X‐ray computed micro‐tomography and synchrotron Fourier‐transform infrared spectroscopy

AbstractRecent excavations at Palù di Livenza (northeastern Italy) revealed a multiphase Neolithic pile dwelling dated between ca. 4,300/4200 and 3,600 cal BC. Three lumps with teeth imprints and a larger amorphous piece from the Late Neolithic layers have been studied by X‐ray computed micro‐tomography (microCT) and synchrotron Fourier‐transform infrared spectroscopy (FTIR). FTIR spectra match well that of birch bark tar and microCT of the larger piece has revealed a rolled‐up structure likely corresponding to bark rolls. The lumps of birch pitch were probably chewed to soften the tar prior to be used as hafting adhesive or therapeutic substance. The rolled‐up inner structure of the larger piece and the remains of birch bark tar and abundant charcoals on its surface suggest it probably corresponds to a rare waste product from allothermic tar production.

Panel Bulu Ayam sebagai Material Dinding Ramah Lingkungan

Chicken meat is one of sources of animal protein that is reliable to support the social and economic life in community. Chickens have feathers, which are waste from the slaughter of poultry. The waste that is generated can cause problems like environmental pollution, unpleasant odour, source of disease, and breathing problem for people that suffer from allergies to chicken feathers. The slaughtering of poultry produces an average feather weight of 4 - 9% of live weight. Thus, technology and disposal methods are needed to reduce threats to the environment. The potential of chicken feathers has been used for pillow filling, duster and accessories. The chicken feathers have attracted the attention of researchers to develop environmentally friendly materials.This study aims to conduct experiments on chicken feather waste, so that can be used for a wall material. The right treatment and composition are needed to form the proper material.The method was experimental engineering, using chicken feather waste as raw material and two alternative adhesive substance (PVAC and white cement). The results indicated that the right composition and treatment in forming chicken feather waste material into wall panels, which are finely chopped chicken feathers and the formation of a 70: 30 and water. The panels formed are expected to meet the needs of building wall materials that have high quality and become realistic materials as the availability of the raw material is abundant. Also, the panels can be a new reference in the architecture field as an alternative environmentally friendly material.

Diaspore traits specialized to animal adhesion and sea current dispersal are positively associated with the naturalization of European plants across the world

Understanding what drives non‐native species naturalization (the establishment of a self‐sustainable population outside its native range) is a central question in invasion science. Plant capacity for long‐distance dispersal (LDD) is likely to influence the spread and naturalization of non‐native species differently according to their introduction pathways. These pathways include intentional introductions (for economic use, e.g. for agriculture), unintentional introductions (e.g. seed contaminants), plant dispersal via human infrastructures (e.g. roads) and plant spread from an adjacent region where the species was previously introduced. We tested the relationship between sets of LDD traits (syndromes) of 10 308 European plant species and their global naturalization incidence (i.e. whether a species has become naturalized or not) and extent (i.e. the number of regions where a species has become naturalized) using the most comprehensive database of naturalized plants worldwide (GloNAF). Diaspore traits allowed the identification of four traditional LDD syndromes, namely those with specializations for dispersal by: wind (anemochorous), animal ingestion (endozoochorous), attached to animals (epizoochorous) and sea currents (thalassochorous). These evolutionary specializations have been historically interpreted by biologists even though actual dispersal is not always related to diaspore syndromes. We found that while epizoochorous and thalassochorous traits are positively associated with global plant naturalization incidence, anemochorous and endozoochorous traits show a negative relationship. Species' residence time outside their native range, their economic use and presence of epizoochorous traits (such as hooks, hairs and adhesive substances) are positively associated with global naturalization extent. Furthermore, we found that plant economic use reduces the influence of LDD syndromes on the naturalization incidence of intentionally introduced plants. While the success of non‐native plants is influenced by a broad array of species‐ and context‐specific factors, LDD syndromes play an important role in this context depending on the economic use of plants.

Multiproxy study of 7500-year-old wooden sickles from the Lakeshore Village of La Marmotta, Italy

The lakeshore site of La Marmotta is one of the most important Early Neolithic sites of Mediterranean Europe. The site is famous for the exceptional preservation of organic materials, including numerous wooden artefacts related to navigation, agriculture, textile production, and basketry. This article presents interdisciplinary research on three of the most complete and well-preserved sickles recovered from the site, yet unpublished. All the components of the tools are analysed: the stone inserts, the wooden haft and the adhesive substances used to fix the stones inside the haft. Our innovative methodology combines use-wear and microtexture analysis of stone tools through confocal microscopy, taxonomical and technological analysis of wood, gas chromatography–mass spectrometry analysis of the adhesive substances, and pollen, non-pollen palynomorphs, and phytolith analysis of the remains incorporated within the adhesive. This multiproxy approach provides a significant insight into the life of these tools, from their production to their use and abandonment, providing evidence of the species of harvested plants and the conditions of the field during the harvesting.

Dynamics of adhesive systems development in dental practice

BACKGROUND: Тhe article presents a review of adhesive systems in terms of their component chemical composition. Seven generations of adhesive systems have been studied. The first generation of adhesive systems emerged in the 1970s. The result of the action was the bond reaction of the adhesive with calcium enamel and dentin. Glycerophosphoric acid dimethacrylate was used. The use of methacrylates in adhesive systems was widespread because polymers with high biological indifference to biological objects are formed when they are polymerized in combination with acrylic resin. The second generation used a lubricated layer to obtain higher adhesion rates. Chloro-substituted phosphate esters of various monomers were used as active groups. The main compound mechanism remained the ionic binding of calcium dentine by chlorophosphate groups. The third generation used a lubricated layer to attach the composite to the dentin in the same way as the second generation. In the chemical composition, aluminosilicates, aluminitrates, hydroxyethylmethacrylate (HEMA), 4-methacryloxyethyltrimethyl anhydride (4-META), and other substances were most often used as active groups. The fourth generation is a multicomponent system that provides a three- and four-step application technique. These systems contain three to four components (conditioner, primer, and adhesive). The technique of their use includes three stages, namely, etching with 37% orthophosphoric acid, priming, and bonding. Adhesive systems of the fifth generation are two-component systems that provide a two-step technique of application. First, acid (etching) is applied to the tooth tissue, and second, the adhesive itself. Adhesive systems of the sixth and seventh generations are one-component self-etching since the adhesive contains acid. From a chemical point of view, these adhesive systems are a mixture of phosphoric esters and adhesive substances. Therefore, analyzing the adhesive composition of seven generations in such way, the mechanism of chemical interaction of adhesive components with hydroxyapatite and dentin has not significantly changed; however, the number of hydrophobic fragments has increased, which significantly increases dentin contact.

Preparation of silica-epoxy superhydrophobic coating with mechanical stability and multifunctional performance via one-step approach

Functionalized nanoparticles can provide the required rough structures and properties, which are an effective way to construct superhydrophobic surfaces. Yet, these surfaces have problems of complicated fabrication and poor adhesive strength. Based on the above problems, the hydrophilic SiO2 nanoparticles are modified with low-surface-energy 1 H, 1 H, 2 H, 2 H-perfluorodecyltrimethylsilane (FAS-17) to synthesize fluorosilane-modified SiO2 (FS) nanoparticles. Furthermore, epoxy resin (EP) containing stable benzene ring and ether bond was introduced as adhesive and anti-corrosion substance to form the superhydrophobic FSEP coating by a one-step approach. The as-prepared coating exhibits high water repellency and adhesion on various substrates, with water contact angle of 162.0º and rolling angle of 2.6º. The coating can withstand 550 cm sandpaper abrasion and resist water droplets with different pH values, showing good mechanical and chemical stability. Additionally, it possesses good durability after weathering in air for 30 d or immersing in saline for 14 d. Moreover, the coating demonstrates excellent multifunctional performance in anti-corrosion, drag reduction and self-cleaning, and its mechanisms of multifunctional applications are analyzed and revealed in detail. It is noteworthy that the corrosion current is decreased by 3 orders of magnitude and the drag reduction rate is enhanced by 28.06 %, after spraying the FSEP coating on the aluminum alloy. This work establishes multifunctional superhydrophobic coating through a simple and effective one-step approach, which will further expand the production scale of superhydrophobic coatings and facilitate their practical applications.

Comparative Evaluation of Intrapulpal Thermal Changes during the Polymerization of Different Adhesive Resin Materials: An In Vitro Study

Aim of this study was to assess the thermal changes within the pulp at the time of polymerization of three different adhesive resin materials. Sixty human premolar teeth that had been recently extracted for orthodontic reasons and were devoid of dental caries/flaws were included in this research. Following preparation of the cavities, all 60 samples consisting of 20 premolars in every group, depending on the adhesive resins that were positioned as were assigned at random to one of the following three groups: Group I: RelyX self-adhesive resin cement; Group II: Breeze self-adhesive resin cement; Group III: Pan F self-etch adhesive resin cement. The temperature changes were calculated using a thermocouple wire attached to a digital thermometer. The dissimilarities amid the baseline temperature as well as the temperatures at different time intervals (1, 5, 10, and 15 minutes) were established. The thermal value was higher at first minute (1.84 ± 0.34) and gradually reduced at 5 minutes (1.36 ± 0.29), 10 minutes (0.62 ± 0.11), and 15 minutes (0.06 ± 0.03) in RelyX self-adhesive resin cement. The maximum thermal value was found at the first minute (2.66 ± 0.21) and gradually reduced at 5 minutes (1.42 ± 0.13), 10 minutes (0.86 ± 0.09), and 15 minutes (0.28 ± 0.01) in Breeze self-adhesive resin cement. The higher thermal value was found at the first minute (1.98 ± 0.19) and gradually reduced at 5 minutes (1.49 ± 0.14), 10 minutes (0.76 ± 0.10), and 15 minutes (0.16 ± 0.09) in Pan F self-etch adhesive resin cement and there was a statistically significant difference found between various time points and with all three adhesive resin material groups (p <0.001). This current research arrived at a conclusion that each of the three adhesive resin substances showed a safe temperature change within the pulp. However, the lowest heat scores within the pulp were depicted by RelyX self-adhesive resin in pursuit by Pan F self-etch adhesive resin cement as well as the Breeze self-adhesive resin cement in that order. The clinical triumph of a restoration is dependent partially on the method of cementation, which is utilized to establish a connection amid the restoration and the tooth. Temporary and permanent pulp inflammation can be avoided by the decreased temperature changes in the adhesive resin cement at the time of polymerization.

Treated wastewater irrigation effects on aggregate stability of Sandy loam soils in Semi-arid Tropical Zone of Nigeria

Irrigation with treated wastewater (TWW) for agricultural production is gradually becoming very important recycling option that substitutes fresh water (FW) particularly in water stressed regions like the Semi-arid Tropical zone of Nigeria. However, owing to high salt concentrations, dissolved organic matter and organic compounds found in the TWW occasionally, its application can have potential adversative impacts such as reduction of soil aggregate stability (SAS), which in turn affects soil quality. To assess the impact of TWW irrigation in comparison to FW irrigation on soils aggregation and SAS, wet sieving technique and the relationship of coefficient of variation (KV) and Mean Weight Diameter (MWD) were applied, while normal standard procedure was used for determination of some selected soil chemical and physical characteristics. The results indicated that the application of TWW increased the soil aggregate stability, and significantly highest (P&lt;0.05) in phase III soils compared to other phases and control treated soils possibly due to relatively high organic matter content in the TWW sites compared to FW sites. Furthermore, the TWW is characterized by low concentration of salinity and sodicity parameters such as EC and Na, and comparatively high microbial glue like adhesive substances from the OC of the TWW soils. This in turn improve the aggregation, structural stability of the topsoil on one hand, and reduce the soils vulnerability to erosion on the other hand by binding micro-aggregates together to form macro-aggregates and larger pore spaces between micro-aggregates. Consequently, leading to improved water infiltration and permeability. Overall, the results indicated that the use of TWW for irrigation is a viable option, but care should be taken on the type and composition of the TWW particularly with regards to soluble salts concentration, organic and inorganic substances, as they can influence soils aggregate stability with other soil physical and chemical properties. This will consequently affect general soil quality and crop yield.

COMPARATIVE EVALUATION OF THE SHEAR BOND STRENGTH OF TWO RESIN CEMENTS WITH THAT OF ZIRCON-BASED CROWNS – AN IN-VITRO STUDY

Introduction: Because of ceramics' exceptional esthetical qualities, the range of materials for implicitly rebuilding missing tooth structures has already grown substantially in recent years. One of the earliest ceramics, silica-based ceramics, needs an adhesive attachment to the tooth structures to keep them from breaking. Previous studies looked at the relationship between the properties of human dentine and the shear bond strength of adhesive on a polished, flat tooth structure surface. For the cementation of inlays, Onlays, crowns, posts, and veneers, resin-based adhesive luting substances are often utilized. the self-adhesive qualities are based on phosphoric-acid methacrylates, which demineralize and penetrate the tooth substrate to provide micromechanical retention.&#x0D; Methodology: This study was undertaken to investigate the shear bond strength between zirconia and two resin-luting types of cement. One is a conventionally used dual-cure resin cement and the other is a new universal self-adhesive self-cure resin cement. Methods: The two self-adhesive self-cured resin cement utilized in the current study, Panavia-F 2.0 and Rely X U 100 were two of these relatively novel products.&#x0D; Result: The number of adhesive and cohesive fractures was calculated for both groups .chi-square test was applied to compare the two parameters in both groups. it was found that 60% of Group RelyX–U100 showed cohesive fractures and 13.33% of group Panavia–F2.0 showed cohesive fractures. There was a highly significant difference found in the type of fractures shown by each group.&#x0D; Conclusion: It is thus concluded from the above study that to bond the zirconia restorations to dentin a better shear bond strength can be observed with respect to self-adhesive self-cure cement rather than the conventional dual resin cement where the application of primer &amp; etchants is required for the bonding process.

Effect of seed inoculation method with Rhizobium species on the germination of alfalfa seeds (Medicago sativa L.)

Inoculation alfalfa seeds with the right Rhizobium strain (nitrogen-fixing bacteria) can stimulate root nodulation and improve plant growth and yield. Different inoculation methods are used to inoculate alfalfa seeds; however, the effect of these methods on the germination of seeds is not well documented. In the present study, the germination of alfalfa seeds was evaluated after using different inoculation methods, i.e. Arabic gum solution and glucose solution as adhesive substances on the surface of the seeds, and charcoal powder and sawdust as seeds coating materials. The adhesive solutions and coating materials were tested separately and in combination. Three concentrations of Arabic gum solution and glucose solution were used (i.e., 5, 12.5, and 25%), alongside untreated seeds as control. Germination counts were started on days 3, 4, 6, 8, 10, and 12. On day 12, the experiment ended and the final germination percentage (FGP) and germination index (GI) were calculated. Application of sole Arabic gum and glucose solution of 5 and 12.5% on the surface of the seeds was beneficial to the germination of the inoculated seeds. The application of sole sawdust in the seedbed enhances germination significantly (p &lt; 0.05) compared with coal powder. Moreover, using sawdust as a coating material in combination with Arabic gum (12.5%) gave significantly (p &lt; 0.05) higher germination. The results demonstrate that using 12.5% of adhesive solution either with sawdust or charcoal powder as coating material did not harm the germination of alfalfa seeds.

The choice of adhesive for the production of yarn glue method

It is proposed to use sericin, a component of silkworm cocoons, as an adhesive compound for the production of yarn by the adhesive method. An experiment was conducted to study the dependence of the adhesion forces of the binder to cellulose on the concentration of the adhesive substance on the example of solutions of PVA, PVA and sericin. A comparative analysis of this dependence is carried out. Mathematical models are constructed to predict the strength of the adhesive joint depending on the concentration of the adhesive composition. The calculation of the adhesion forces per one elementary fiber is carried out.

Using CaCO3-doped package to improve correlated color temperature uniformity of white light-emitting diodes

&lt;span&gt;The white light-emitting diode (WLED) has been the most advance lighting method currently, however, the fabrication process of this configuration still has drawbacks which negatively affect its color quality. This research was conducted to provide a method for WLED’s lighting output enhancement. Since CaCO&lt;sub&gt;3&lt;/sub&gt; particles are excellent for thermal stability enhancement, especially when being combined with an adhesive substance, we decided to integrate CO&lt;sub&gt;3&lt;/sub&gt; particles into resin matrix such as melamine formaldehyde (MF) and investigate their influences on the optical properties, including color uniformity and lumen output, of the WLED. The results showed that CaCO3 and MF resin are beneficial to the light scattering efficiency, which results in higher luminous flux and chromatic quality for WLED packages. In addition to that, the appropriate amounts of MF resin and CaCO&lt;sub&gt;3&lt;/sub&gt; for reaching the best lumen efficiency and color quality are figured out at 1% and 10%, respectively. Moreover, another advantage of using MF resin and CaCO&lt;sub&gt;3&lt;/sub&gt; for fabricating WLEDs is cost effectiveness. Hence, it has turned out that CaCO&lt;sub&gt;3&lt;/sub&gt; and MF resins can be potential materials for next high-quality WLED generations.&lt;/span&gt;

Much more than hooked: Setal adaptations for camouflage in Macrocoeloma trispinosum (Latreille, 1825) (Crustacea: Decapoda: Brachyura)

Several majoid crabs are known to adhere exogenous materials to their bodies, a behaviour called decoration. Until now, the adhesion of exogenous materials to the body is most attributed to the well-known hooked setae. Here, we analysed the carapace of Macrocoeloma trispinosum (Latreille, 1825) under light and electron microscopy to study the different mechanisms allowing majoid crabs to decorate themselves. Five setal types are described here, of which four for the first time: velvet type I, velvet type II, depressa and cattail seta. These setae are morphologically and histologically detailed, and new hypotheses about the fixation of exogenous material on the carapace are explored. M. trispinosum has a complex setal apparatus for the adhesion of the decoration, with tegumental ducts along the shaft of most setae. These tegumental ducts are connected to glands formed by large cells arranged radially (rosette or acini) at the base of the setae, in the connective tissue, just below the epithelium. We could observe these glands in different stages of maturation, and no valve-like structure was observed, which may indicate a continuous flow of protein secretion that could serve as an adhesive substance found in the apex of most setae. This is the first record indicating a potential chemical adhesion mechanism aiding the masking process in decorator crabs.

Superhydrophobic modification of nanocellulose based on an octadecylamine/dopamine system

We prepared super-hydrophobic nanocellulose films using a non-toxic octadecylamine/polydopamine system. Octadecylamine, a low surface energy material, was used to provide hydrophobic alkyl long chains. Polydopamine was produced by dopamine under alkaline conditions, creating an adhesive substance, which reinforced the hydrophobic long chains and increased the surface roughness of nanocellulose. The effects of reagent concentration, reaction temperature, and reaction time on hydrophobicity were then investigated. The results showed that with a 1:1 mass ratio of nanocellulose to octadecylamine, and reacting at 60 °C for 4 h, the contact angle of the obtained composite membrane reached 168.2°. Scanning electron microscope images revealed that the modified nanocellulose had a smaller particle size and more uniform distribution, which effectively improved the hydrophobicity of the nanocellulose. Thus, the green preparation of superhydrophobic films with high-temperature resistance and wear resistance was realized, which contributed to the high-value utilization of nanocellulose.

Nuisance mucilage produced by Lindavia intermedia (Bacillariophyceae) in New Zealand lakes

ABSTRACT The invasive centric diatom Lindavia intermedia arrived in New Zealand in recent decades. It produces a pelagic mucilage, which forms an adhesive substance known as lake snow. While determining cell concentrations of L. intermedia is relatively straightforward, methods to estimate mucilage concentration in lake water have not yet been developed. Two methods for lake snow quantification are reported here: a dragged line, or “snow tow,” and in situ filtration. A chemical assay for hexosamine, as an estimate of chitin content, and an atomic absorption method, which measures silicon, were used to measure these components of lake snow. Samples from 4 lakes revealed a correlation between snow tow and filtration data; in principle, the snow tow method (used by municipal authorities) could be calibrated and made quantifiable using the filtration method. Expression of the chitin synthase gene in summer/autumn (but not in winter/spring) correlated with abundance of the chitin component of lake snow, aligning with anecdotal evidence for the timing of its development in lakes. By contrast, cell densities correlated poorly with lake snow abundance. Cell concentrations relative to chitin concentrations were also higher in winter/spring than in summer/autumn across lakes. Dry weight and silicate in lake snow relative to chitin varied by lake and season. The quantification of lake snow and its adhesiveness are important parameters for assessing its nuisance value and fouling characteristics and for developing measures to prevent and remediate its incursion in lakes.

How to Wear a Sandy Coat: Secretory Cells in the Dorsal Epidermis in the Sea Cucumber Holothuria atra (Echinodermata: Holothuroidea).

Holothuria atra is a black sea cucumber commonly found on the sandy bottom of Okinawan coral reefs. The body surface of H. atra is usually covered with sand; however, sand never covers the body of another black congener, Holothuria leucospilota, which is sympatrically distributed with H. atra. The epidermal structures were examined in these two species by means of transmission electron microscopy to determine how sand adheres to the surface of H. atra. While the epidermis was basically composed of support cells bearing microvilli and vacuolated cells probably corresponding to mucus cells, two types of granular cells, type 1 and 2, were also found at the tip of the tube feet. These granular cells were closely similar in structure to secretory cells that have been supposed to secrete adhesive substances in other holothurians. Type 1 granular cells were also found in the dorsal epidermis of H. atra but not in H. leucospilota. Therefore, adhesive secretion by type 1 granular cells probably enables the attachment of sand to the H. atra body.

Properties of corrugated roofing sheet material from sugarcane bagasse fibers

This research was aimed to study the properties of corrugated roofing sheet material from sugarcane bagasse fibers by using 10% adhesive substances comprising Phenol formaldehyde (PF) and polymeric diphenylmethane diisocyanate (PMDI) resins. The corrugated roofing sheet had a density of 500, 700 and 900 kg m−3 and a thickness of 6 mm. Physical, mechanical and thermal properties tests were performed according to industry standards. The results revealed that sheets with high density had low moisture content, low water absorption and low thickness swelling. PMDI resin provided the best adhesive quality. As for the mechanical property investigation, modulus of rupture, modulus of elasticity, the impact strength. Regarding the thermal property investigation, were thermal conductivity and resistance covered. It was also found that the higher density they had, the better mechanical properties they owned. The PMDI-based corrugated roofing sheet with 900 kg m−3 density achieved the best mechanical properties. They can be highly possible to be used as a substitute material for asbestos roofing tiles.

Influence of UVA radiation on growth, biofilm formation and bioleaching capacity of Leptospirillum ferrooxidans

Ultraviolet-A (UVA) radiation is one of the most stressful oxidative agents that bacteria have to face in natural environments. The effect of this radiation on growth, survival, biofilm formation, and bioleaching activity of two Leptospirillum ferrooxidans strains was studied, comparing the collection strain DSM2705 with FAM-RA2, a strain recently isolated from Famatina (La Rioja, Argentina), at 3869 m above sea level (ma.s.l.). We demonstrated that the isolate FAM-RA2 was more UVA resistant than the collection strain DSM2705 in kinetic growth and biofilm formation assays. However, both strains presented a similar behavior in their bioleaching capacity. Higher levels of intracellular reactive oxygen species (ROS) after UVA exposure were detected in DSM2705 strain, suggesting the presence of stronger defensive mechanisms against oxidative stress in FAM-RA2 strain. Assays of biofilm formation showed that UVA radiation induced cell adhesion and extracellular polymeric substance (EPS) production in the collection strain DSM2705, but not in the FAM-RA2 strain. The ability of UVA radiation to increase biofilm formation in DSM2705 led us to suppose that this agent could promote its bioleaching activity; however, under these studied conditions, this stress agent did not enhance metal sulfide dissolution. This study provides first insights into the effects of UVA radiation on the physiological features of acidophilic microorganisms.

The use of gelling agents to preserve burnt teeth within the dental alveoli for dental human identification - a study utilising sheep mandibles.

Dental comparison is one of the primary methods of scientific identification of severely incinerated human remains. However, due to the fragile nature of the remains dental structures may be lost or damaged during recovery and transportation, limiting the amount of evidence available for examination. In addition to protecting the head, stabilization of the oral structures with an adhesive substance that will not interfere with the dental examination is ideal. A number of materials have been described in previous studies, however, no optimal method has yet to be indicated. Many of these materials contain petrochemicals, which have been shown to be a contamination risk. Wheatpaste solution has been demonstrated to be a viable alternative but has demonstrated handling issues and is not optimal in some environments. This study explores the stabilization of burnt teeth utilizing gelatin and agar solutions as alternatives to wheatpaste. Like wheatpaste solution, these materials are inexpensive, simple to use and are free from petrochemicals. Anterior sections of sheep mandibles were incinerated and subsequently solutions of agar, gelatin or wheatpaste were applied. The jaw fragments were then subjected to vibration and the number of teeth retained within the bone was recorded and compared to untreated incinerated jaw fragments.Although agar solution demonstrated serious handling issues, gelatin solution provided stabilization equivalent to that of wheatpaste.Gelatin also performed well at lower temperature conditions under which wheatpaste has been shown to perform poorly.