Formation of nanometer-scale grooves in silicon with a scanning tunneling microscope

Grooves a few nanometers wide can be formed on a Si(111) surface with a scanning tunneling microscope when the tip is above a critical voltage. This may provide a promising approach to nanodevice fabrication. The dependence of the critical voltage on tunneling current, tip polarity, and tip material was studied with silver, gold, platinum, and tungsten tips. The results are consistent with field emission of positive and negative silicon ions. The variation of critical voltage with current is explained quantitatively by a simple tunneling equation that includes the effect of the contact potential between tip and sample.     

Incidence of Error in Oestrus Detection Based on Secondary Oestrus Signs in a 24-h Tie-Stalled Dairy Herd with Low Fertility

Oestrus detection error and conception rates after AI based only on secondary oestrus signs were evaluated in a high yielding, 24-h tie-stalled dairy herd with low fertility, using milk progesterone profiles. Oestrus detection was based on the secondary oestrus signs such as restlessness, swelling, congestion of vulva and clear mucus discharge. Sixty eight AI conducted after observing the secondary oestrus signs in 44 animals were included in the study. Of the 68 AI, 53 (77.9%) were conducted in the follicular phase, and 13 (19.1%) and 2 (2.9%) were carried out in the luteal phase and during pregnancy, respectively. The overall error in oestrus detection based on milk progesterone profiles was 22.1%. The oestrus detection error did not differ significantly among different secondary oestrus signs. None of the AI conducted in the luteal phase resulted in conception, whereas 20.8% of AI conducted in the follicular phase resulted in conception. No significant difference in the conception rates among the groups of cows with different secondary oestrus signs was shown. The high incidence of oestrus detection error in this study might have been caused by the detection of cows in oestrus based only on secondary oestrus signs due to the confinement of animals. In conclusion, there was a high incidence of heat detection error in the 24-h tie-stalled dairy herd and oestrus detection based only on secondary oestrus signs resulted in low conception rate.     

Interaction of rumen bacteria as assumed by colonization patterns on untreated and alkali‐treated rice straw

Colonization patterns of representative rumen bacteria were compared between untreated rice straw (UTS) and sodium hydroxide‐treated rice straw (SHTS). UTS and SHTS were incubated in the rumen of sheep for 10 min, 1, 2, 6, 12, 24, 48 and 96 h using the nylon bag method. The population sizes of 13 representative bacterial species or groups were quantified by real‐time PCR. The total bacterial population size (abundance) was similar in both UTS and SHTS. Fibrobacter succinogenes showed a higher population size compared to other fibrolytic species and was detected at a higher level in SHTS (3.7%) than in UTS (2.6%). Ruminococcus albus and Ruminococcus flavefaciens were also detected at higher levels in SHTS (0.15% and 0.29%) than in UTS (0.03% and 0.18%). Population sizes of non‐fibrolytic species, such as Selenomonas ruminantium, Anaerovibrio lipolytica and Succinivibrio dextrinosolvens were higher in UTS than in SHTS. Coefficient of determination (r²) on population changes between bacterial species or groups were higher in UTS than in SHTS, suggesting the necessity of stronger bacterial interactions for UTS digestion. Therefore, not only colonization of fibrolytic species, but also synergistic interactions between different bacterial species may be key to the ruminal digestion of rice straw.     

Imatinib elicited a favorable response in a dog with a mast cell tumor carrying a c-kit c.1523A>T mutation via suppression of constitutive KIT activation

Target therapy using the tyrosine kinase inhibitor imatinib is one of the new therapeutic approaches for canine mast cell tumors (MCTs). In the present report, we demonstrate a clinical response to imatinib in a dog with MCT carrying a c-kit c.1523A>T mutation. Moreover, the effect of this mutation on the phosphorylation status of KIT and the inhibitory potency of imatinib on the phosphorylation of the mutant KIT were examined in vitro. A dog with a MCT tumor mass on the right forelimb sole with lymph node metastasis and mastocytemia was treated with imatinib. The MCT mass markedly shrank and mastocytemia became undetectable with 2 weeks of treatment. The lymph node enlarged by metastasis became normal in size with 5 weeks of treatment. From the sequencing analysis of c-kit in tumor cells, a substitution mutation c.1523A>T that alters the amino acid composition (p.Asn508Ile) within the extracellular domain of KIT was identified. The mutant KIT expressed on 293 cells showed ligand-independent phosphorylation and imatinib suppressed this phosphorylation in a dose-dependent manner. From these findings, imatinib was considered to elicit a clinical response in a canine case of MCT via inhibition of the constitutively activated KIT caused by a c-kit c.1523A>T mutation.     

人工林木材高频真空干燥与其他干燥方法的比较(英文)

该文介绍了日本木材工业的产品结构以及木材干燥的现状和发展,并对人工林木材高频真空干燥(RFV)与其他干燥方法进行了比较.在日本80%以上的锯材用于建筑用材.日本目前人工林工业用材林树种主要是日本柳杉(Sugi)和日本扁柏(Hinoki),占全部人工林工业用材林的近80%.该文对日本木材干燥的全部干燥方法进行了介绍,着重介绍了人工林木材高频真空干燥的应用与发展现状、存在的问题、解决方案以及工业化应用前景.     

Profiles of a pathogenic Entamoeba histolytica-like variant with variations in the nucleotide sequence of the small subunit ribosomal RNA isolated from a primate (De Brazza's guenon).

A pathogenic Entamoeba histolytica-like variant (JSK2004) with genetic variations and a novel isoenzyme pattern was isolated from a De Brazza's guenon. A homology of 99.1% was found between the clones of E. histolytica (HM-1:IMSS) and JSK2004 in the 1,893 nucleotide bases of the small subunit rRNA (SSU-rRNA) gene. The DNA of the pathogenic amoeba species was also extracted from two sterile liver abscesses during the autopsies of an Abyssinian colobus and a Geoffroy's spider monkey occurring in the same institution in which JSK2004 was isolated, and the homology of the nucleotide sequences in the SSU-rRNA gene of the DNAs was identical to that of JSK2004.     

Simulation-based estimation of BSE infection in Japan

The first case of bovine spongiform encephalopathy (BSE) in Japan was found in September 2001. As a result, national BSE surveillance systems in slaughterhouses and farms were introduced between October 2001 and April 2004. All cattle, with the exception of those under 24 months of age that die at farms, now undergo compulsory testing when they die or are slaughtered. The removal of specified risk material (SRM) from all slaughtered cattle and a ban on the feeding of meat-and-bone meal to all farm animals were implemented in October 2001. However, infected cattle that died or were slaughtered before these measures were put into practice could have been a source of infection to other cattle through the rendering process. The slaughtered cattle could also have been a source of infection to humans via SRM that entered the food chain. The purpose of this study was to estimate the number of BSE-infected cattle that could have been a source of infection to cattle and humans before October 2001. Since all typical cases were dairy cattle, this study focused on the dairy cattle population. We developed a simulation model to obtain the year of death and the final disposition of infected cows born in each year from 1996 to 2001. In this model, the dairy cattle population was divided into birth cohorts, and parameters regarding its population dynamics were assumed to be constant. Using this model, the total number of infected cattle in each birth year was estimated by maximum likelihood estimation using data on the number of detected cases from 2002 to 2006. Finally, the number of infected cattle that died or were slaughtered each year was estimated by Monte-Carlo simulation using the same model with the total number of infected cattle estimated by maximum likelihood estimation. It was estimated that the majority of infected cattle that could have been sources of infection before 2001 were born in 1996. The total number born in 1996 was estimated to be 155 (95% confidence interval: 90-275). Of these 155 cattle, 56 died or were slaughtered before October 2001, after the accumulation of infectious agent in their bodies. Only 5 of these 56 cattle were estimated to have been slaughtered. Therefore, the number of infected cattle that could have served as a source of human infection would appear to have been a very limited subset of the BSE-infected cattle in Japan.     

A dynamic, optimal disease control model for foot-and-mouth-disease: II. Model results and policy implications

A dynamic optimization model was used to search for optimal strategies to control foot-and-mouth disease (FMD) in the three-county region in the Central Valley of California. The model minimized total regional epidemic cost by choosing the levels of depopulation of diagnosed herds, preemptive depopulation, and vaccination. Impacts of limited carcass disposal capacity and vaccination were also examined, and the shadow value, the implicit value of each capacity, was estimated. The model found that to control FMD in the region, (1) preemptive depopulation was not optimal, (2) vaccination, if allowed, was optimal, reducing total cost by 3–7%, (3) increased vaccination capacity reduced total cost up to US$ 119 per dose, (4) increased carcass disposal capacity reduced total cost by US$ 9000–59,400 per head with and without vaccination, respectively, and (5) dairy operations should be given preferential attention in allocating limited control resources.     

Cytosolic-free calcium transients in cultured vascular smooth muscle cells: microfluorometric measurements

Microfluorometric recordings were made of changes in the concentration of cytosolic-free calcium in cultured rat vascular smooth muscle cells treated with quin 2, an intracellularly trapped dye, under several conditions. Nitroglycerin decreased calcium in both the presence and absence of extracellular calcium and strongly and progressively decreased the extent of transient increases in calcium induced by repeated applications of caffeine in the absence of extracellular calcium. Therefore nitroglycerin probably decreases cytosolic-free calcium by accelerating the extrusion of calcium through the sarcolemmal membrane.     

Greenhouse gas emissions after a prescribed fire in white birch-dwarf bamboo stands in northern Japan,focusing on the role of charcoal

Forest fires affect both carbon (C) and nitrogen (N) cycling in forest ecosystems, and thereby influence the soil–atmosphere exchange of major greenhouse gases (GHGs): carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O). To determine changes in the soil GHG fluxes following a forest fire, we arranged a low-intensity surface fire in a white birch forest in northern Japan. We established three treatments, having four replications each: a control plot (CON), a burned plot (BURN), and a plot burned with removal of the resulting charcoal (BURN-CHA). Soil GHG fluxes and various properties of the soil were determined on four or five occasions during a period that spanned two growing seasons. We observed increased concentrations of ammonium-N (NH₄-N) in BURN and BURN-CHA after the fire, while nitrate–N (NO₃-N) concentration was only increased in BURN-CHA after the fire. The soil CO₂ flux was significantly higher in CON than in BURN or BURN-CHA, but there was no difference in soil CH₄ uptake between the three treatments. Moreover, the N₂O flux from BURN-CHA soil was slightly greater than in CON or BURN. In BURN-CHA, the soil N₂O flux peaked in August, but there was no peak in BURN. We found temporal correlations between soil GHG fluxes and soil variables, e.g. soil temperature or NO₃-N. Our results suggest that environmental changes following fire, including the increased availability of N and the disappearance of the litter layer, have the potential to change soil GHG fluxes. Fire-produced charcoal could be significant in reducing soil N₂O flux in temperate forests.