Surface tension of iron hydride formed by the reaction of iron-silicate-water at 5GPa and high temperature was studied based on the texture observation of the quenched samples. It was found that the surface tension of iron hydride is much larger compared with that of the silicates. Therefore, in a mixture of partially molten silicates and molten iron hydride, the iron hydride tends to accumulate into disconnected pockets and percolation is hard to occur. This result implies that in the proto Earth, the gravitational separation of the molten iron from the partially molten silicates could occur only when the degree of melting of silicates was very high.
The contents in a glass kohl bottle excavated from the stratum of the 14th-15th centuries, al-Tur in South Sinai, Egypt were analyzed to find their characteristics and provenances. The contents of the bottle were found to be mainly phosgenite and laurionite by X-ray diffraction and X-ray fluorescence analysis. As a reference, a black pigment used for a modern kohl in Egypt was also analyzed and the results were discussed.
Biological activities of geometrical isomers of retinoic acid on human acute promyelocytic leukemia cell line HL-60 were analized by strictly excluding the effects of artificial isomerization. Varying from previous reports, 9-cis-retinoic acid showed over tenfold higher activity than all-trans-retinoic acid. Activity of 13-cis-retinoic acid corresponded roughly to that of all-trans-retinoic acid, and activity of 9, 13-di-cis-retinoic acid was approximately 1/10 of the level of all-trans-retinoic acid. Activities of the isomers on HL-60 cells to inhibit growth and to induce differentiation into granulocytes were parallel. all-trans-Retinoic acid and 9-cis-retinoic acid acted synergetically on HL-60 cells. Further, all-trans-retinoic acid acted additively with 13-cis-retinoic acid and with 9, 13-di-cis-retinoic acid. In contrast, 9-cis-retinoic acid acted synergetically with 13-cis-retinoic acid and with 9, 13-di-cis-retinoic acid.
DNA amplification by polymerase chain reaction (PCR) was employed to detect the mycoplasma-like organism (MLO) associated with paulownia witches'-broom (PaWB). A 1.2kb DNA fragment of PaWB MLO was amplified with primer pair R16F2R2. A minimum of only 16pg total nucleic acids from infected paulownia tissue culture maintained at 25-28°C was needed to detect PaWB MLO. An appropriate concentration of total nucleic acids for amplification used for detection of PaWB MLO from the tissue culture was demonstrated to be 240pg/μl to 6.5ng/μl. PaWB MLO DNA content in total nucleic acids from MLO-infected tissue culture was as high as 5 times that from MLO-infected paulownia plant grown at 23-25°C in the greenhouse. Results showed that the amplification by PCR is highly effective in detecting the low concentrations of PaWB MLO known to occur in irregular patterns in diseased paulownia plants.
We investigated the number of tyrosine hydroxylase (TH)-positive neurons in the rat substantia nigra (SN) after unilateral lesion of SN dopamine neurons with intranigral 6-hydroxydopamine (6-OHDA) injection. Non-radioactive in situ hybridization procedure and immunohistochemistry detected much less (<5%) TH-positive neurons in the lesioned SN, compared with the contralateral side. Single administration of a dopamine antagonist haloperidol failed to increase TH labeling on the lesioned side, although it increased that in the contralateral SN pars reticulata (SNr), as in the case of unlesioned animals. These results indicate that 6-OHDA destroyed not only TH-positive SN neurons but also TH-negative but -inducible SNr neurons. It is probable that these “TH inducible” SNr neurons are dopaminergic neurons although they usually do not express TH at detectable levels.
A simple way of understanding the structure of the DNA recognition code of transcription factors is shown taking two DNA binding motifs as examples (the C4 class zinc binding proteins and the C2H2 zinc fingers). Interaction between DNA and factors of the motifs can be understood as that between two lines, a line connecting residue positions on the surface of a recognition helix and a line connecting base positions in the DNA major groove. The base-residue pairing along the two lines are summarised in the stereochemical charts. The DNA recognition table for each of the two motifs, which can be used for prediction and design of recognition helix-DNA interactions, can be created by choosing residue-base partners from the chemical code table according to the stereochemical chart specific to the motif.