Separation of long DNA chains using non-uniform electric field: a numerical study

We study migration of DNA molecules through a microchannel with a series of electric traps controlled by an ac electric field. We describe the motion of DNA based on Brownian dynamics simulations of a beads-spring chain. Our simulation demonstrates that the chain captured by an electrode escapes from the binding electric field due to thermal fluctuation. We find that the mobility of chain would depend on the chain length; the mobility sharply increases when the length of a chain exceeds a critical value, which is strongly affected by the amplitude of the applied ac field. Thus we can adjust the length regime, in which this microchannel well separates DNA molecules, without changing the structure of the channel. We also present a theoretical insight into the relation between the critical chain length and the field amplitude.Comment: 12 pages, 9 figure

Inhibitory Effect of Flavonoids on the Efflux of N-Acetyl 5-Aminosalicylic Acid Intracellularly Formed in Caco-2 Cells

N-acetyl 5-aminosalicylic acid (5-AcASA) that was intracellularly formed from 5-aminosalicylic acid (5-ASA) at 200 μM was discharged 5.3, 7.1, and 8.1-fold higher into the apical site than into the basolateral site during 1, 2, and 4-hour incubations, respectively, in Caco-2 cells grown in Transwells. The addition of flavonols (100 μM) such as fisetin and quercetin with 5-ASA remarkably decreased the apically directed efflux of 5-AcASA. When 5-ASA (200 μM) was added to Caco-2 cells grown in tissue culture dishes, the formation of 5-AcASA decreased, and, in addition, the formed 5-AcASA was found to be accumulated within the cells in the presence of such flavonols. Thus, the decrease in 5-AcASA efflux by such flavonols was attributed not only to the inhibition of N-acetyl-conjugation of 5-ASA but to the predominant cellular accumulation of 5-AcASA. Various flavonoids also had both of the effects with potencies that depend on their specific structures. The essential structure of flavonoids was an absence of a hydroxyl substitution at the C5 position on the A-ring of flavone structure for the inhibitory effect on the N-acetyl-conjugation of 5-ASA, and a presence of hydroxyl substitutions at the C3′ or C4′ position on the B-ring of flavone structure for the promoting effect on the cellular accumulation of 5-AcASA. Both the decrease in 5-AcASA apical efflux and the increase in 5-AcASA cellular accumulation were also caused by MK571 and indomethacin, inhibitors of MRPs, but not by quinidine, cyclosporin A, P-glycoprotein inhibitors, and mitoxantrone, a BCRP substrate. These results suggest that certain flavonoids suppress the apical efflux of 5-AcASA possibly by inhibiting MRPs pumps located on apical membranes in Caco-2 cells

NMR analyses on the interactions of the yeast Tim50 C-terminal region with the presequence and Tim50 core domain

AbstractThe mitochondrial targeting signal in the presequence of mitochondrial precursor proteins is recognized by Tom20 and subsequently by Tim50 in mitochondria. Yeast Tim50 contains two presequence binding sites in the conserved core domain and in the fungi-specific C-terminal presequence binding domain (PBD). We report the NMR analyses on interactions of a shorter variant of PBD (sPBD), a shorter variant of PBD, with presequences. The presequence is recognized by sPBD in a similar manner to Tom20. sPBD can also bind to the core domain of Tim50 through the presequence binding region, which could promote transfer of the presequence from sPBD to the core domain in Tim50

A study on refurbishment of multi-family houses in Malaysia - housing developed by Kuala Lumpur City Government in the ’80s -

In Asian countries including Malaysia, a lot of new residential areas (; New towns) are developed because of the rapid population increase in urban areas during mass housing era ;60-80’s. The designs of the residential buildings provided to New Towns have been influenced by Western design based on modernism, which has different origin from Asian traditional architectures. Residents living in New Towns refurbish their dwellings in daily basis, and these refurbishments represent gaps between their diversified living requirements and the provided standards on which dwelling design is based. In this study, we carried out investigations on refurbishments by residents for multi-family houses in Kuala Lumpur. Our focus is providing the right and eligible procedures and methodologies to configure sustainable New Town houses considering Malaysian cultural aspects. We extracted three areas from large-scale residential complexes developed during early mass housing era in Kuala Lumpur as investigation targets. Questionnaires were given to the residents, 102 of whom answered them, and 37 of whom agreed photographing insides of the dwellings, sketching their living plans, and hearing their daily lives. 54 among 102 answered they had conducted some refurbishments. Major refurbishments are categorized as follows; installation/removal of walls/dividers, changes on floor/wall surface finishes, expansion to outside, addition of bay windows and window roofs. In Conclusion, ・ Relationship between residents’ ways of living and refurbishments is clarified. Residents’ living activities spread not only inside of dwellings but also to semi-external spaces such as balconies. ・ Various kinds of refurbishments including additions of window roofs and expansions to outside suggest ways how to adjust dwellings to local climate conditions and ways of living. ・ The ways of living and refurbishments show their living needs in semi-external spaces with appropriate air circulation. ・ The housing design in the future should be based on local climate, environments and cultures

An Integrated Approach to Developing Japanese Students' English Presentation and Discussion Skills

We examined the types of difficulties that Japanese high school students have in English presentation and discussion activities. We conducted factor analysis (principal factor method with promax rotation) on the survey data, which was divided into four stages: (1) the presentation preparation stage; (2) the presentation stage; (3) the listening stage; and (4) the discussion stage. The results showed that students had difficulty with the following skills during each of the four stages: (1) "effective ways of providing information," "revision," and "collaborative work" during the presentation preparation stage; (2) "basic presentation skills," "handling questions," and "audience management" during the presentation stage ; (3) "active interaction" and "active understanding" during the listening stage; and (4) "overcoming communication anxiety," "adaptation to classroom activities," "problem solving approach," and "self-relativization" during the discussion stage

An Integrated Approach to Developing Japanese Students' English Presentation and Discussion Skills

We examined the types of difficulties that Japanese high school students have in English presentation and discussion activities. We conducted factor analysis (principal factor method with promax rotation) on the survey data, which was divided into four stages: (1) the presentation preparation stage; (2) the presentation stage; (3) the listening stage; and (4) the discussion stage. The results showed that students had difficulty with the following skills during each of the four stages: (1) "effective ways of providing information," "revision," and "collaborative work" during the presentation preparation stage; (2) "basic presentation skills," "handling questions," and "audience management" during the presentation stage ; (3) "active interaction" and "active understanding' during the listening stage; and (4) "overcoming communication anxiety," "adaptation to classroom activities," "problem solving approach," and "self-relativization" during the discussion stage

Inhibitory Effect of Flavonoids on the Efflux of N-Acetyl 5-Aminosalicylic Acid Intracellularly Formed in Caco-2 Cells

Recommended by Mostafa Z. Badr N-acetyl 5-aminosalicylic acid (5-AcASA) that was intracellularly formed from 5-aminosalicylic acid (5-ASA) at 200 μM was discharged 5.3, 7.1, and 8.1-fold higher into the apical site than into the basolateral site during 1, 2, and 4-hour incubations, respectively, in Caco-2 cells grown in Transwells. The addition of flavonols (100 μM) such as fisetin and quercetin with 5-ASA remarkably decreased the apically directed efflux of 5-AcASA. When 5-ASA (200 μM) was added to Caco-2 cells grown in tissue culture dishes, the formation of 5-AcASA decreased, and, in addition, the formed 5-AcASA was found to be accumulated within the cells in the presence of such flavonols. Thus, the decrease in 5-AcASA efflux by such flavonols was attributed not only to the inhibition of N-acetyl-conjugation of 5-ASA but to the predominant cellular accumulation of 5-AcASA. Various flavonoids also had both of the effects with potencies that depend on their specific structures. The essential structure of flavonoids was an absence of a hydroxyl substitution at the C5 position on the A-ring of flavone structure for the inhibitory effect on the N-acetylconjugation of 5-ASA, and a presence of hydroxyl substitutions at the C3 or C4 position on the B-ring of flavone structure for the promoting effect on the cellular accumulation of 5-AcASA. Both the decrease in 5-AcASA apical efflux and the increase in 5-AcASA cellular accumulation were also caused by MK571 and indomethacin, inhibitors of MRPs, but not by quinidine, cyclosporin A, P-glycoprotein inhibitors, and mitoxantrone, a BCRP substrate. These results suggest that certain flavonoids suppress the apical efflux of 5-AcASA possibly by inhibiting MRPs pumps located on apical membranes in Caco-2 cells