排序方式: 共有55条查询结果,搜索用时 0 毫秒
1.
Pollen, phytolith, and plant macrofossil analyses were carried out on the cultural layers of Helsinki Old Town excavated by the Helsinki City Museum and dated to the 15–17th centuries. Cultural mineral soil layers, a former ditch, a well, one waste pit, one waste heap and three house areas were investigated. The results show that-within certain limits-pollen in the mineral soil reflects the cultural changes of the local settlement from rural to urban. Among the main anthropogenic indicators, the high NAP (non-arboreal pollen) frequencies, the low pollen concentration values, and especially the high frequencies of Cichoriaceae (Liguliflorae) pollen should be emphasized. The macrofossil data were used to determine the species list of the herb pollen and to make a more detailed reconstruction of the local vegetation at Helsinki Old Town. 相似文献
2.
The effect of a strong electric field generated by molecular dipoles on the ground state electronic structure and the Q and B states as well as the lowest charge transfer (CT) excited state of porphine–2,5-dimethyl-1,4-benzoquinone (PQ) complex has been investigated theoretically. Density functional theory DFT and time-dependent DFT (TDDFT) with the BH&HLYP hybrid functional have been applied in these calculations. The molecular dipole effect was generated by imposing one or two helical homopeptides consisting of eight α-aminoisobutyric acid residues (Aib8) close to the PQ complex. The molecular dipoles in a close proximity to the PQ complex expose it to an electric field of the order of magnitude of 109 V/m. The presence of the ambient molecular dipoles affects mainly the energy of the lowest CT state and barely the energies of the Q and B states. The molecular dipoles affect the energies of the excited states in a similar way as an external electrostatic field. Hence, the electric field induced by the molecular dipoles of the helical peptides could be used analogously to the external electrostatic field to control electron transfer (ET) in the PQ complex. 相似文献
3.
4.
Hung-Chun Yu Jennifer L. Sloan Gunter Scharer Alison Brebner Anita M. Quintana Nathan P. Achilly Irini Manoli Curtis R. Coughlin II Elizabeth A. Geiger Una Schneck David Watkins Terttu Suormala Johan L.K. Van Hove Brian Fowler Matthias R. Baumgartner David S. Rosenblatt Charles P. Venditti Tamim H. Shaikh 《American journal of human genetics》2013
5.
Vuosku J Jaakola L Jokipii S Karppinen K Kämäräinen T Pelkonen VP Jokela A Sarjala T Hohtola A Häggman H 《Molecular biotechnology》2004,27(3):209-215
An automated nucleic acid extraction procedure with magnetic particles originally designed for isolation of deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) from animal tissues was tested for plant material. We isolated genomic DNA and total RNA from taxonomically diverse plant species representing conifers (Scots pine), broad-leaved trees (silver birch and hybrid aspen), dwarf shrubs (bilberry), and both monocotyledonous (regal lily) and dicotyledonous (Saint John's wort, round-leaved sundew, and tobacco) herbaceous plants. Buffers developed for DNA extraction were successfully used in addition to manufacturer's extraction kits. The quality of RNA was appropriate for many applications, but the quality of DNA was not always sufficient for polymerase chain reaction (PCR) amplification. However, we could strikingly improve the quality by eliminating the adherent compounds during the extraction or later in the PCR phase. Our results show that the use of the procedure could be extended to diverse plant species. This procedure is especially suitable for small sample sizes and for simultaneous processing of many samples enabling large-scale plant applications in population genetics, or in the screening of putative transgenic plants. 相似文献
6.
Peippo J Viitala S Virta J Räty M Tammiranta N Lamminen T Aro J Myllymäki H Vilkki J 《Molecular reproduction and development》2007,74(11):1373-1378
We report a method for multiplex genotyping of bovine embryo microblade biopsies. We have tested the reliability of the method and the viability of the embryos in vitro and in vivo. Two polymorphic gene markers (GHR F279Y and PRLR S18N) associated with milk production traits and one marker for sex diagnosis (ZFX/ZFY) were genotyped simultaneously with a method that combines nested PCR and allelic discrimination. To test the accuracy of genotyping, in the first experiment the genotypes of 134 biopsies from in vitro produced embryos were compared to genotypes determined from the corresponding embryos after biopsy. The method proved to be highly accurate as only in three cases (two for PRLR S18N and one for GHR F279Y) out of 395 genotypes the genotype was in disagreement between the two samples. The viability of similarly biopsied embryos was tested in parallel: after 24-hr culture 94.6% of embryos recovered in vitro. In the second experiment, a total of 150 in vivo-produced embryos were biopsied on Day 7 and genotyped. After the genotyping results were obtained on Day 8, female embryos were selected for transfer. From a total of 57 selected embryos 43 were transferred individually and 14 as pairs. After single embryo transfers, 19 recipients became pregnant and after embryo transfers in pairs one became pregnant. The success of genotyping was tested with the genotypes of donors and bulls and also from the hair samples of born calves. All calves were females and of the same genotypes determined from the biopsy. 相似文献
7.
Katila T 《Animal reproduction science》2005,89(1-4):31-38
In this review, effects of the composition of the inseminate on uterine response and pregnancy rates in mares are discussed. The inseminate can differ for volume, sperm concentration, total sperm numbers, presence, absence, or proportion of seminal plasma, and extender composition. Semen can be used as fresh, cooled, or frozen. The site of semen deposition also plays a role; semen is deposited either into the uterine body (standard artificial insemination (AI)) or into the tip of the uterine horn ipsilateral to the preovulatory follicle (deep AI) using the hysterocopical or transrectally guided techniques. In addition to pregnancy rates, some uterine responses to the inseminate are considered including myometrial contractions, transport and elimination of sperm, and uterine inflammation, which is reflected as numbers of polymorphonuclear leukocytes, enzyme levels, and presence of intrauterine fluid. Reproductively normal and abnormal mares are compared. 相似文献
8.
9.
10.