Search

In the event of fires, natural disasters, and other events associated with high temperature, bones and teeth are the only source of genetic material for identifying human or animal carcasses. To obtain reliable final results of identification tests, the use of appropriate nucleic acid extraction methods is crucial. Therefore, the main objective of this research was to evaluate the effectiveness of selected methods of DNA isolation from animal burnt bones and teeth. In addition, the effect of the duration of high temperature on the stability of nuclear and mitochondrial DNA in these tissues was determined, as well as the possibility of using the genetic material obtained for species identification of remains of unknown origin. Bones and teeth collected during necropsy of dogs were burnt in a laboratory oven at 400 °C (752 °F; 673.15 K) for 5, 10, 15, 30, 45 and 60 min. DNA was isolated according to four different protocols, using three commercial kits, i.e. the PrepFiler® Forensic DNA Extraction Kit from Applied Biosystems, the QIAamp® DNA Investigator Kit from QIAGEN, and the DNA Mini Kit from Syngen, as well as a classic organic method. The effectiveness of these methods was compared by assessing the amount of isolated DNA using Real-Time PCR and its purity using a NanoDrop™ spectrophotometer. Each isolate was also subjected to PCR with primers designed to amplify fragments of dog mitochondrial DNA. The effectiveness of species identification was assessed for the method showing the best DNA recovery and for the organic method, considered the gold standard for analysis of difficult material. The QIAamp® DNA Investigator Kit showed the highest efficiency of DNA isolation from bones and teeth burnt for 15 min (the longest burning time for which DNA could still be recovered from bones and teeth). The results of the experiment clearly indicate that DNA stability in hard tissues depends on how long they burn. In the case of exposure to 400 °C, reliable genetic testing, including species identification, is possible when the burning time does not exceed 15 min. Among the hard tissues examined, bones proved more suitable than teeth for identification purposes. It was also concluded that identification of bone remains with extreme heat damage should be based on mitochondrial DNA analysis. [ABSTRACT FROM AUTHOR]

Copyright of Pediatric Endocrinology, Diabetes & Metabolism is the property of Termedia Publishing House and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We present a case of a young patient with synchronic tumours of both testicles. There was embryonal cancer found in the right testis, while in atrophic testis benign fibrous tumour was present. During surgery a sample of healthy looking tissue from the left side was collected. Neither signs of spermatogenesis nor carcinoma in situ were found in the specimen. The patient is under ongoing follow-up. Due to the fact that the patient plans to establish a family, his semen was preserved for fertilisation (homologous insemination) prior to the treatment. The atrophic testicle in a sub- or infertile man, who had a history of testicle cancer, increases significantly the risk of carcinoma in situ or invasive cancer in a second testicle. [ABSTRACT FROM AUTHOR]

An experimental analysis of mechanical behaviour for aluminium-based fibre metal laminates under compression after impact was conducted. Damage initiation and propagation were evaluated for critical state and force thresholds. Parametrization of laminates was done to compare their damage tolerance. Relatively low-energy impact had a marginal effect on fibre metal laminates compressive strength. Aluminium-glass laminate was more damage-resistant than one reinforced with carbon fibres (6% vs. 17% of compressive strength loss); however, aluminium-carbon laminate presented greater energy dissipation ability (around 30%). Significant damage propagation before the critical load was found (up to 100 times the initial damaged area). Damage propagation for assumed load thresholds was minor in comparison to the initial damage size. Metal plastic strain and delaminations are dominant failure modes for compression after impact.

The combination of fibre metal laminates (FML) and sandwich structures can significantly increase the performance under impact of FMLs. The goal of this work was to create a material that will combine the superior properties of FMLs and foam sandwich structures in terms of the impact resistance and simultaneously have lower density and fewer disadvantages related to the manufacturing. An extensive impact testing campaign has been done using conventional fibre metal laminates (carbon- and glass-based) and in the proposed fibre foam metal laminates to assess and compare their behaviour. The main difference was observed in the energy absorption mechanisms. The dominant failure mechanism for fibre foam laminates is the formation of delaminations and matrix cracks while in the conventional fibre metal laminate the main failure mode is fibre cracking due to high local stress concentrations. The reduction in the fibre cracking leads to a better after-impact resistance of this type of structure improving the safety of the structures manufactured with these materials.

This article presents selected aspects of an interlaminar shear strength and failure analysis of hybrid fiber metal laminates (FMLs) consisting of alternating layers of a 2024-T3 aluminium alloy and carbon fiber reinforced polymer. Particular attention is paid to the properties of the hybrid FMLs with an additional interlayer of glass composite at the metal-composite interface. The influence of hygrothermal conditioning, the interlaminar shear strength (short beam shear test), and the failure mode were investigated and discussed. It was found that fiber metal laminates can be classified as a material with significantly less adsorption than in the case of conventional composites. Introducing an additional layer of glass composite at the metal-composite interface and hygrothermal conditioning influence the decrease in the interlaminar shear strength. The major forms of damage to the laminates are delaminations in the layer of the carbon composite, at the metal-composite interface, and delaminations between the layers of glass and carbon composites.

The purpose of the work was the effect of metal volume fraction of fiber metal laminates on damage after dynamic loads based upon the example of innovative hybrid titanium-carbon composite laminates. The subject of the study was metal-fiber hybrid titanium-carbon composite laminates. Four types of hybrid titanium-carbon laminates were designed with various metal volume fraction coefficient but constant thickness. Based on the results, it can be stated that changes in the metal volume fraction coefficient in the range of 0.375-0.6 in constant thickness titanium-carbon composite laminates do not significantly affect their resistance to impacts in the energy range of 5-45 J. It was concluded that there were no significant differences in maximum force values, total contact time, and damage range. Some tendency towards a reduction in the energy accumulation capacity was observed with an increase in thickness of the metal part in relation to the total thickness of the laminate, especially in the lower impact energy range. This can result in the lower bending stiffness of laminates with lower metal content and potential elastic strain of the composite part before the initiation of the fiber damage process.

The aim of the study was to assess the selected properties of a hybrid organic-inorganic silane sol-gel coating (HSG) used in hybrid fiber metal laminates (FML) in a corrosion environment. The HSG coating on the aluminum alloy was produced using 3M™ AC130-2 formulation consisting of 3-glycidoxypropyl-trimethoxysilane (GPTMS) and tetra-n-propoxyzirconium (zirconium(IV) propoxide) (TPOZ). Laminates consisted of aluminum alloy AA2024-T3 sheets, with carbon fiber reinforced polymers (CFRPs) and a glass fiber reinforced metal-composite structure (GFRP). Potentiodynamic and polarization curve and impedance (EIS) tests were carried out on HSG at ambient temperatures after 1 h and 150 h of soaking. Neutral 0.5 M NaCl and 0.8 M NaCl solutions were used for open circuit potential (OCP) and potentiodynamic tests, and 0.5 NaCl was used for the EIS test. A neutral salt spray (NSS) test was applied to laminates with a 12 week exposure period. The results obtained revealed that the HSG coating did not provide sufficient protection against corrosion of the aluminum alloy in direct contact with an aggressive environment but was effective as an interlayer. Local aluminum sheet perforation did not lead to delamination at the metal-composite interface regardless of the type or configuration of the composite. This confirms the durability of HSG used in FMLs.

Metal-organic frameworks with unsaturated metal centers in their crystal structures, such as Ni/DOBDC and Mg/DOBDC, are promising adsorbents for carbon dioxide capture from flue gas due to their high CO(2) capacities at subatmospheric pressures. However, stability is a critical issue for their application. In this paper, the stabilities of Ni/DOBDC and Mg/DOBDC are investigated. Effects of steam conditioning, simulated flue gas conditioning, and long-term storage on CO(2) adsorption capacities are considered. Results show that Ni/DOBDC can maintain its CO(2) capacity after steam conditioning and long-term storage, whereas Mg/DOBDC does not. Nitrogen isotherms for Mg/DOBDC show a drop in surface area after steaming, corresponding to the decrease in CO(2) adsorption, which may be caused by a reduction of unsaturated metal centers in its structure. Conditioning with dry simulated flue gas at room temperature only slightly affects CO(2) adsorption in Ni/DOBDC. However, introducing water vapor into the simulated flue gas further reduces the CO(2) capacity of Ni/DOBDC., (© 2011 American Chemical Society)

Metal-organic frameworks (MOFs) have recently attracted intense research interest because of their permanent porous structures, huge surface areas, and potential applications as novel adsorbents and catalysts. In order to provide a basis for consideration of MOFs for removal of carbon dioxide from gases containing water vapor, such as flue gas, we have studied adsorption equilibrium of CO(2), H(2)O vapor, and their mixtures and also rates of CO(2) adsorption in two MOFs: HKUST-1 (CuBTC) and Ni/DOBDC (CPO-27-Ni or Ni/MOF-74). The MOFs were synthesized via solvothermal methods, and the as-synthesized products were solvent exchanged and regenerated before experiments. Pure component adsorption equilibria and CO(2)/H(2)O binary adsorption equilibria were studied using a volumetric system. The effects of H(2)O adsorption on CO(2) adsorption for both MOF samples were determined, and the results for 5A and NaX zeolites were included for comparison. The hydrothermal stabilities for the two MOFs over the course of repetitive measurements of H(2)O and CO(2)/H(2)O mixture equilibria were also studied. CO(2) adsorption rates from helium for the MOF samples were investigated by using a unique concentration-swing frequency response (CSFR) system. Mass transfer into the MOFs is rapid with the controlling resistance found to be macropore diffusion, and rate parameters were established for the mechanism.

A diverse collection of 14 metal-organic frameworks (MOFs) was screened for CO(2) capture from flue gas using a combined experimental and modeling approach. Adsorption measurements are reported for the screened MOFs at room temperature up to 1 bar. These data are used to validate a generalized strategy for molecular modeling of CO(2) and other small molecules in MOFs. MOFs possessing a high density of open metal sites are found to adsorb significant amounts of CO(2) even at low pressure. An excellent correlation is found between the heat of adsorption and the amount of CO(2) adsorbed below 1 bar. Molecular modeling can aid in selection of adsorbents for CO(2) capture from flue gas by screening a large number of MOFs.

Hydrothermal stability is a pertinent issue to address for many industrial applications where percent levels of water can be present at temperatures ranging from subambient to several hundred degrees. Our objective is to understand relative stabilities of MOF materials through experimental testing combined with molecular modeling. This will enable the ultimate design of materials with improved hydrothermal stability, while maintaining the properties of interest. The tools that we have employed for these studies include quantum mechanical calculations based upon cluster models and combinatorial steaming methods whereby a steam stability map was formulated according to the relative stability of different materials. The experimental steaming method allows for high throughput screening of materials stability over a broad range of steam levels as well as in-depth investigation of structural transformations under more highly resolved conditions, while the cluster model presented here yields the correct trends in hydrothermal stability. Good agreement was observed between predicted relative stabilities of materials by molecular modeling and experimental results. Fundamental information from these studies has provided insight into how metal composition and coordination, chemical functionality of organic linker, framework dimensionality, and interpenetration affect the relative stabilities of PCP materials. This work suggests that the strength of the bond between the metal oxide cluster and the bridging linker is important in determining the hydrothermal stability of the PCP. Although the flexibility of the framework plays a role, it is not as important as the metal-linker bond strength. This demonstration of alignment between experimental and calculated observations has proven the validity of the method, and the insight derived herein insight facilitates direction in designing ideal MOF materials with improved hydrothermal stability for desired applications.