Dependence of runout distance on the number of rock blocks in large-scale rock-mass failure experiments

To examine how the number of rock blocks affects the rock-mass runout distance, large-scale outdoor rockfall experiments were physically performed using cubiform granite rock blocks on a slope prepared with granite slabs under both dry and water-saturated conditions. To learn more about the runout mechanism, numerical simulations were also conducted using three-dimensional DEM to reproduce the physical experiments under dry conditions. Longitudinal rock-mass runout distance between the gravity centre in the initial rock block assembly before failure and the apparent gravity centre at final deposition was 10 % larger for experiments under water-saturated conditions than those under dry conditions, with identical numbers of rock blocks in the physical experiments. The physical and numerical experiments revealed that rock blocks at the front and top surfaces had a longer runout distance than those at the rear and bottom surfaces. A rock block scarcely surpassed the rock blocks in front longitudinally and the rock blocks next to it laterally. The equivalent coefficient of friction between gravity centres was positively correlated with the number of rock blocks, which contradicts the findings of a negative correlation between the volume of sturzstroms (rockfall avalanches) and the equivalent coefficient of friction in classic studies on the long runout mechanisms. Our results were likely attributable to the fact that more kinetic energy was dissipated due to repeated inelastic intercollisions with other surrounding rock blocks and granite slabs when the initial rock-mass volume (number of rock blocks) was larger.     

Genetic correlations among fatty acid compositions in different sites of fat tissues, meat production, and meat quality traits in Duroc pigs

This study estimated genetic parameters for fatty acids of different sites of fat tissue, meat production, and meat quality traits of Duroc pigs selected during 7 generations for ADG, LM area, backfat thickness (BF), and intramuscular fat (IMF). For this study, 394 barrows and 153 gilts were slaughtered at 105 kg of BW. High heritabilities for C18:0 of outer and inner subcutaneous fat tissue were estimated, respectively, as 0.54 and 0.51; those of intermuscular and intramuscular fat were 0.40 and 0.51, respectively. Genetic and phenotypic correlations of ADG and BF with saturated fatty acids of outer and inner subcutaneous fat were positive, but those with C16:1 and C18:2 were negative, and those with C18:1 were nearly zero. Genetic and phenotypic correlations between LM area and respective fatty acids showed opposite results. Respective genetic and phenotypic correlations of melting points with C18:0 and C18:1 were positive and high, and negative and high, respectively. Genetic correlations between cooking loss and SFA (C14:0, C16:0, and C18:0) of IMF were positive and moderate: 0.56, 0.47, and 0.47, respectively. On the other hand, monosaturated fatty acid of C18:1 was highly and negatively correlated with cooking loss (-0.61). Moreover, high genetic correlation between meat color (pork color standard and lightness) and fatty acid compositions of IMF suggest that the SFA (C14:0, C16:0, and C18:0) were correlated genetically with meat lightness and that unsaturated fatty acid compositions (C18:1 and C18:2) were correlated with meat darkness. Results of this study suggest that the fatty acid composition of adipose tissue is correlated genetically with meat production and meat quality traits.     

Black tea polyphenols, theaflavins, prevent cellular DNA damage by inhibiting oxidative stress and suppressing cytochrome P450 1A1 in cell cultures.

Tea polyphenols have been demonstrated as chemopreventive agents in a number of experimental models. However, less is known about the mechanism of chemoprevention by black tea compared with that of green tea. Some beneficial properties of theaflavins, the black tea polyphenols, were investigated in the present study. Theaflavins showed inhibitory effects on H(2)O(2)- and tert-butyl hydroperoxide (tBuOOH)-induced cytotoxicity (evaluated by tetrazolium bromide reduction), cellular oxidative stress (detected by oxidation of 2', 7'-dichlorofluorescin), and DNA damage (measured by amount of 8-OHdG and comet assay) in rat normal liver epithelium cell RL-34 cell lines. In addition, theaflavins also exhibited suppression of cytochrome P450 1A1 induced by omeprazole in the human hepatoma HepG2 cell line. Furthermore, when HepG2 cells were pretreated with omeprazole to induce CYP1A1, then exposed to benzo[a]pyrene (B[a]P), DNA damage was observed using the comet assay. However, theaflavins could inhibit this DNA damage. These results indicated that theaflavins could prevent cellular DNA damage by inhibiting oxidative stress and suppressing cytochrome P450 1A1 in cell cultures.     

The activity of lecithin: Cholesterol acyltransferase in the serum of cows at parturition or with fatty liver

The activity of lecithin: cholesterol acyltransferase (LCAT), which is responsible for esterification of plasma cholesterol, was evaluated in bovine serum. It was associated with the high-density lipoprotein fraction that contains apolipoprotein A–I, an activator of LCAT. In lactating cows, the activity was around 1000 U (decrease in nmol of free cholesterol per h per ml of serum), slightly higher than in 1-month-old calves. LCAT activity decreased around parturition, at which the time the serum concentrations of cholesteryl esters and free cholesterol were concomitantly decreased. A reduced LCAT activity was also found in cows with fatty livers induced by the administration of ethionine. In the cows with fatty livers, the serum concentration of cholesteryl esters was markedly decreased, whereas that of free cholesterol was only slightly decreased, thereby increasing the free- to esterified-cholesterol ratio. These results suggest that the decrease in LCAT activity may be involved in the reduction in fertility associated with fatty liver because esterification of cholesterol by LCAT is essential for its transport from the liver to peripheral tissues, such as the corpus luteum, and because cholesterol serves as the source of progesterone synthesis in the latter organ.Abbreviations apoA–I apolipoprotein A–I - CE cholesteryl esters - CM chylomicron - FC free cholesterol - HDL high-density lipoprotein - IDL intermediate-density lipoprotein - LCAT lecithin:cholesterol acyltransferase - LDL low-density lipoprotein - VHDL very high-density lipoprotein - VLDL very low-density lipoprotein     

Mg/Ca Thermometry in Coral Skeletons

The magnesium-to-calcium (Mg/Ca) ratio of coral skeletons from Ishigaki Island, Ryukyu Islands, Japan, closely tracked sea surface temperature (SST) over an 8-year period. Measurements were made with the fast technique of inductively coupled plasma-atomic emission spectrometry. The variation of the coral Mg/Ca ratio with SST change is about four times that of the current, widely used coral strontium-to-calcium ratio. The temporal and geographic variation of the seawater Mg2+/Ca2+ ratio probably has little influence on coral Mg/Ca variation. Results indicate that the coral Mg/Ca ratio has the potential to provide fast, precise, high-resolution proxies for past tropical SSTs.     

Pathological features of olfactory neuroblastoma in an axolotl (Ambystoma mexicanum)

A one-year-old, female Mexican axolotl (Ambystoma mexicanum) had a rough-surfaced, polypoid, pink tumor mass of approximately 10 mm in diameter in the oral cavity. Histologically, the tumor extended from the ethmoturbinate region and into the oral cavity and had replaced some of the maxillary bone tissue. The tumor mass was composed of a lobular architecture of small round-shaped tumor cells with occasional Flexner-Wintersteiner-like rosette formation. There were no metastatic lesions in the other organs. Immunohistochemically, the tumor cells were partly positive for several neural markers (class III beta-tubulin, S-100 protein, and doublecortin) and intensely positive for an epithelial marker (cytokeratin AE1/AE3). These results suggest that the present tumor originated from neuroectodermal tissue. Considering the location and histological and immunohistochemical features of the tumor, a diagnosis of olfactory neuroblastoma was made.     

Natural occurrence of neoplastic lesions in young sprague-dawley rats

It is important for the assessment of toxicological effects of chemicals to know what kinds of neoplasms naturally occur in the early life of experimental animals. In the present study, we demonstrated spontaneous neoplasms in Sprague-Dawley rats used in 4-, 13- and 26-week toxicity studies conducted at Bozo Research Center in the last decade. The tumors, which were first observed in 19-week-old animals, included anterior adenoma of the pituitary, follicular cell adenocarcinoma and C cell adenoma of the thyroids, nephroblastoma of the kidneys, basal cell tumor of the skin and malignant lymphoma. Thereafter, hemangiosarcoma of the tongue, adenocarcinoma of the submandibular glands, histiocytic sarcoma of the spleen, oligodendroglioma of the brain and adenocarcinoma and fibroadenoma of the mammary glands were detected in 32-week-old animals. The incidences of mammary adenocarcinoma and pituitary anterior adenoma were higher than those of other tumors. The present results showed that the same tumors as reported in aged rats could also develop in younger rats.     

Immunohistochemical observation of canine degenerative myelopathy in two Pembroke Welsh Corgi dogs

Immunohistochemistry was performed to assess whether oxidative stress and/or denatured proteins play roles in the pathogenesis of canine degenerative myelopathy (DM). Two Pembroke Welsh Corgi (PWC) dogs with a homozygous mutation (c.118G>A) in the canine superoxide dismutase 1 (SOD1) gene were examined. The pathological features of the dogs were consistent with those of previous cases of DM in PWC. In the spinal lesions, diffuse SOD1 expression was observed in the neurons while no inclusion-like aggregates had formed, which disagreed with the findings of a previous study. A unique inducible nitric oxide synthase (iNOS) staining pattern in reactive astrocytes and a significant increase in ubiquitin immunoreactivity in the spinal lesions were also observed. These findings indicate the involvement of oxidative stress and the accumulation of ubiquitinated proteins in the pathogenesis of canine DM, whereas the role of SOD1 remains unclear.