The mechanical properties of red deer antler bone when used in fighting

We assessed the hydration state of antlers and its effect on antler mechanical properties compared with wet femur. Red deer antlers were removed from the head at various times, from a few days after velvet shedding till late in the season, and weighed weekly until after casting time. Antlers cut just after losing their velvet lost weight rapidly in the first few weeks, then settled down and changed weight very little, the latter changes correlating with air relative humidity. Antlers cut later showed little weight change at any time. The water content of cortical and trabecular parts of the contralateral antler was assessed after cutting. Most of the weight loss was from the cancellous, not the cortical, part of the antler. Wet and dry specimens from the antlers, and wet specimens from deer femora, were tested mechanically. Compared with wet bone, wet antler had a much lower modulus of elasticity and bending strength, but a higher work to fracture. Compared with wet bone, dry antler showed a somewhat lower Young's modulus, but a considerably higher bending strength and a much higher work to fracture. The impact energy absorption of dry antler was much greater than that of wet bone. In red deer, the antler is effectively dry during its use in fights, at least in southern Spain. In addition, dry antler, compared with ordinary bone, shows mechanical properties that suit it admirably for its fighting function.

Cell growth in a pinned soap froth

Experimental kinetic data on soap froth cell growth in a random array of fixed pinning centers is reported. The scaling of our two-dimensional data is analyzed and compared with pinning-free growth. The obtained data agree fairly well with a proposed cell growth law. We also discuss the relationship between the pin concentration and the final cell size.

Identification of peptide sequences specific for serum antibodies from human papillomavirus-infected patients using phage display libraries

Three random phage display peptide libraries were screened with sera from human papillomavirus (HPV)-infected patients to characterize the specificities of antibodies present in patients' sera and to identify molecules that correspond to or mimic natural epitopes; 141 phage clones were randomly selected in three rounds of bioselection and their binding properties were analyzed in ELISA using sera from 36 patients with confirmed HPV 16 infection and 24 healthy control female blood donors. Sixteen of 36 (44%) patients' sera reacted with at least 1 phage clone, and only 2 of 24 female donors' sera showed positive reaction with 1 of the selected clones. We conclude that the combination of various disease-specific epitopes generated by screening of phage display peptide libraries may potentially lead to a multicomponent diagnostic assay for the early detection of HPV infection and precancerous cervical lesions, making possible the prevention of one of the most common cancers in women.

Dowel space preparation in root canals filled with glass ionomer cement

The aim of this study was to evaluate post space preparation difficulties in canals filled with Ketac Endo and with Grossman's sealer. Sixty-three single-rooted teeth were prepared using a step-back technique and were divided into four groups: group 1--canals were irrigated with 25% tannic acid and filled with Ketac Endo and a single-cone technique; group 2--canals were irrigated with 1% sodium hypochlorite and fillings done as in the previous group; group 3--canals were irrigated with 25% tannic acid and filled with Ketac Endo and one gutta-percha cone previously adapted with chloroform; and group 4--canals were irrigated with 1% sodium hypochlorite and filled with Grossman's sealer and a lateral condensation technique. After 72 h, canals post space were prepared using Peeso drills. The time required was measured in seconds and analyzed by Tukey multiple comparison test (level 5%). Post space preparation time for groups 1 to 3 was longer than for group 4 and longer for group 1 than for groups 2 to 4.