Comparative analysis of the morphology, chemistry and structure of the tibiotarsus, humerus and keel bones in laying hens.

1. Bone properties are adapted to their specific functions in the animal, so various types of bones develop different characteristics depending on their location in the skeleton.2. The aim of this research was to compare the chemical composition, mineral characteristics and structural organisation in tibiotarsus, humerus and keel bones as representatives of hen skeletal mineralisation. Complementary analytical techniques, such as X-ray radiography, optical and electron microscopy, thermogravimetry and 2D X-ray diffraction, were used for characterisation.3. The humerus had a thinner cortex and cortical bone mineral had higher crystallinity and a greater degree of crystal orientation than the tibiotarsus. The humerus generally lacks medullary bone although, when present, it has a higher mineral content than seen in the tibiotarsus. These differences were attributed to the different forces that stimulate bone formation and remodelling.4. The keel cortical bone had a lower degree of mineralisation than the tibiotarsus or humerus. Its degree of mineralisation decreased from the cranial to the distal end of the bone. This gradient may affect keel mechanical properties, making it more prone to deformation and fractures.5. Data from studying different bones in laying hens can help to understand mineralisation as well as finding solutions to prevent osteoporosis-related fractures.

Influence of Spectroscopic Techniques on the Estimation of the Degree of Conversion of Bulk-fill Composites.

OBJECTIVES: To compare the degree of conversion (DC) of different flowable and sculptable bulk-fill composites (BFC), at 0- and 4-mm depths from the surface, by Fourier transform infrared (FTIR), attenuated total reflection FTIR (ATR-FTIR), and FT-Raman spectroscopic techniques. METHODS AND MATERIALS: Six BFC were investigated, including three sculptable composites (Admira Fusion [Voco], Aura Bulk Fill [SDI], and X-tra Fill [Voco]) and three flowable composites (Venus Bulk Fill [Heraeus], Filtek [3M], and X-tra Base [Voco]). Three molds of each composite were light cured as specified by the manufacturer. For each mold, slices corresponding to 0-mm (surface) and 4-mm depth were analyzed by spectroscopic techniques: ATR-FTIR, FTIR, and FT-Raman. The spectra of uncured composite material were used as an analytical control for background subtraction of the treated composite. The area and amplitude of the reference peaks (1607 and 1637 cm-1) were obtained to calculate the DC percentage at 0- and 4-mm depth. A Kruskal-Wallis nonparametric test was used for materials, and paired comparisons were made using Mann-Whitney nonparametric test. Wilcoxon's rank test was used for comparison between spectroscopic methods and between 0- and 4-mm depth in each composite. Significance was accepted at p<0.05. RESULTS: FTIR showed significantly lower DC values, both in areas and amplitudes of the peaks, when compared with the results reported by different BFC. Differences between the surface and 4-mm depth were detected more precisely by FT-Raman. ATR-FTIR obtained DC values significantly higher than those obtained by FTIR. CONCLUSIONS: The vibrational spectroscopy method significantly influenced DC measurements of the flowable and sculptable BFC explored.