Traversability and connectivity of the middle graph of a graph

AbstractWe define a graph M(G) as an intersection graph Ω(F) on the point set V(G) of any graph G. Let X(G) be the line set of G and F = V′(G) ∪ X(G), where V′(G) indicates the family of all one point subsets of the set V(G). Let M(G) = Ω(F). M(G) is called the middle graph of G. The following theorems result: 1.Theorem 1. Let G be any graph and G+ be a graph constructed from G. Then we have L(G+)≅M(G), where L(G+) is the line graphof G+2.Theorem 2. Let G be a graph. The middle graph M(G) of G is hamiltonian if and only if G contains a closed spanning trail.3.Theorem 3. If a graph G is eulerian, then the middle graph m(G) of G is eulerian and hamiltonian.4.Theorem 4. If M(G) is eulerian, then G is eulerian and M(G) is hamiltonian.5.Theorem 5. Let G be a graph. The middle graph M(G) of G contains a closed spanning trail if and only if G is connected and without points of degree ⩽ 1.6.Theorem 6. If a graph G is n-line connected, then the middle graph M(G) is n-connected

On-line preconcentration using dual mini-columns for the speciation of chromium(III) and chromium(VI) and its application to water samples as studied by inductively coupled plasma-atomic emission spectrometry

On-line preconcentration system for the selective, sensitive and simultaneous determination of chromium species was investigated. Dual minicolumns containing chelating resin were utilized for the speciation and preconcentration of Cr(III) and Cr(VI) in water samples. In this system, Cr(III) was collected on first column packed with iminodiacetate resin. Cr(VI) in the effluent from the first column was reduced to Cr(III), which was collected on the second column packed with iminodiacetate resin. Hydroxyammonium chloride was examined as a potential reducing agent for Cr(VI) to Cr(III). The effects of pH, sample flow rate, column length, and interfering ions on the recoveries of Cr(III) were carefully studied. Five millilitres of a sample solution was introduced into the system. The collected species were then sequentially washed by 1 M ammonium acetate, eluted by 2 M nitric acid and measured by ICP-AES. The detection limit for Cr(III) and Cr(VI) was 0.08 and 0.15 mu g l-1, respectively. The total analysis time was about 9.4 min. The developed method was successfully applied to the speciation of chromium in river, tap water and wastewater samples with satisfied results. </p

Airborne microorganisms in the indoor environment of Syowa Station in Antarctica

Airborne bacterial and fungal numbers in the buildings of Syowa Station in Antarctica were examined for 9 months in 2001. The number of bacteria or fungi was less than 20 or 70/m^3 in the dining room and washroom. The average number of bacteria or fungi was less than 1/50 or 1/5 of those in Japan and Europe, respectively, and remained constant regardless of season. The number of airborne microorganisms appeared to depend on drying of the indoor environment by the use of air-conditioners

Leukemia autopsies in Japan

For the purpose to know whether the annual increase of leukemia incidence in Japan is due to some leukemogenic factors or due to the increased detection rate, the authors made some statistical survey of autopsy cases in which the diagnosis is reliable and not any type of leukemias escape the detection. The results showed that acute leukemias, which are found mostly in younger age, is actually increasing. In addition, it has been deduced that among the suspected factors the increase in ionizing radiation will be one of the most probable factors for the increase in leukemia incidence</p

Effects of Mountain Winds on Air Temperature in an Urban Area during Summer Nights

To clarify the effects of mountain winds on urban temperatures, meteorological observations were conducted in the summers of 2008 and 2009 in Nagano City, central Japan. Hamada et al. (2006) showed that mountain winds blew along the Susobana River, extending into the center of Nagano City. This study selected Nagano Prefectural Office (NPO), which is near the center of Nagano City as a site to observe mountain winds blowing into the city, while Nagano Local Me teorological Observatory (NLMO) at the periphery of the city was selected as an observation site not to mountain winds. Wind conditions at NPO and NLMO were classified as days with (15 cases) and without (37 cases) mountain winds, respectively. Average air temperature, wind direction and speed, and relative humidity at the two points were compared for each case. As a result, at NPO, average wind speed was about 5 m/s, air temperature dropped, and relative humidity increased on days with mountain winds. On these days, air temperature was reduced by up to 2°C, with an average drop of 0.5°C. The drop in temperature with the mountain winds was negatively correlated (r = -0.46,p < 0.001) with wind speed, and the relationship depended on the strength of radiative cooling

Estimating the False Discovery Rate Using Mixed Normal Distribution for Identifying Differentially Expressed Genes in Microarray Data Analysis

The recent development of DNA microarray technology allows us to measure simultaneously the expression levels of thousands of genes and to identify truly correlated genes with anticancer drug response (differentially expressed genes) from many candidate genes. Significance Analysis of Microarray (SAM) is often used to estimate the false discovery rate (FDR), which is an index for optimizing the identifiability of differentially expressed genes, while the accuracy of the estimated FDR by SAM is not necessarily confirmed. We propose a new method for estimating the FDR assuming a mixed normal distribution on the test statistic and examine the performance of the proposed method and SAM using simulated data. The simulation results indicate that the accuracy of the estimated FDR by the proposed method and SAM, varied depending on the experimental conditions. We applied both methods to actual data comprised of expression levels of 12,625 genes of 10 responders and 14 non-responders to docetaxel for breast cancer. The proposed method identified 280 differentially expressed genes correlated with docetaxel response using a cut-off value for achieving FDR <0.01 to prevent false-positive genes, although 92 genes were previously thought to be correlated with docetaxel response ones

Cytotoxic Sesterterpenoids from Bornean Sponge Spongia sp.

Four scalarane sesterterpenoids, scalarolide acetate (1), scalarolide (2), 12-O-deacetyl-12 -epi-19-O-methylscalarin (3) and methyl 18- hydroxy- 19-norscalar-16 -en-20- carboxylate (4) were isolated from the Bornean sponge Spongia sp. The distinction between 12α-OAc and 12β-OAc, and 19-olide and 20-olide in sesterterpenes were revealed as well as previously not assigned relative configuration at 18-OH of 4 is reported herein for the first time. In addition, compounds 1-3 showed strong cytotoxic activities against adult T-cell leukemia (ATL), S1T cells. This is the first record of scalarane sesterterpenes from the Bornean sponge