155 research outputs found
Measurement of the profiles of disorder-induced localized resonances in photonic crystal waveguides by local tuning
Near the band edge of photonic crystal waveguides, localized modes appear due
to disorder. We demonstrate a new method to elucidate spatial profile of the
localized modes in such systems using precise local tuning. Using deconvolution
with the known thermal profile, the spatial profile of a localized mode with
quality factor () is successfully reconstructed with a resolution of
m
Effect of pregnancy and foetal number on diameter of corpus luteum, maternal progesterone concentration and oxidant/antioxidant balance in ewes
The aim of this study was to determine the changes in diameter
of corpus luteum (CL), maternal progesterone (P) concentration,
lipid peroxidation and non-enzymatic antioxidant levels
along with enzymatic antioxidant activities in pregnant ewes
bearing single and twin foetuses. The ewes were selected from
healthy animals that were brought to the abattoir for
slaughtering. The ewes were divided into three groups: Group
1 (non-pregnant, non-oestrous, n = 30), Group 2 (pregnant
bearing a single foetus, n = 30) and Group 3 (pregnant
bearing twin foetuses, n = 12) after they were slaughtered.
Pregnant ewes were in the first half of the pregnancy. The
diameter of CL and P concentration of pregnant ewes bearing
a single foetus or twin foetuses were found higher than that
found in non-pregnant ewes. Similarly, the P concentration of
pregnant ewes bearing twin foetuses was higher than that
found in pregnant ewes bearing a single foetus. Malondialdehyde
(MDA) level in pregnant ewes bearing twin foetuses was
higher than that found in both non-pregnant and pregnant
ewes bearing a single foetus. The serum glutathione (GSH)
level and glutathione-peroxidase (GSH-Px) activity of pregnant
ewes bearing twin foetuses were found lower than that
found in non-pregnant ewes. Additionally, the GSH-Px
activity of pregnant ewes bearing twin foetuses was found
lower than that found in pregnant ewes bearing a single foetus.
No significant difference was found between pregnant ewes
bearing female and male foetus with respect to diameter of CL,
P concentration and oxidative stress parameters. There were
significant positive correlations between foetal number (0, 1, 2)
and diameter of CL, P concentration, MDA level, and between
P concentration and diameter of CL, MDA level. However,
significant negative correlations were found between foetal
number (0, 1, 2) and GSH level, GSH-Px activity, and between
P concentration and GSH-Px activity. In conclusion, the
diameter of CL enlarges, P production increases and
oxidant ⁄ antioxidant balance impairs because of the gestation
stress in ewes during pregnancy
Carbon deficiencies in the primaries of some classical Algols
The equivalent widths of C II 4267 \AA line were measured for the
mass-gaining primary stars of the 18 Algol-type binary systems. The comparison
of the EWs of the gainers with those of the single standard stars having the
same effective temperature and luminosity class clearly indicates that they are
systematically smaller than those of the standard stars. The primary components
of the classical Algols, located in the main-sequence band of the HR diagram,
appear to be C poor stars. We estimate relative to the Sun
as -1.91 for GT Cep, -1.88 for AU Mon and -1.41 for TU Mon, indicating poorer C
abundance. An average differential carbon abundance has been estimated to be
-0.82 dex relative to the Sun and -0.54 dex relative to the main-sequence
standard stars. This result is taken to be an indication of the transferring
material from the evolved less-massive secondary components to the gainers such
that the CNO cycle processed material changed the original abundance of the
gainers. There appear to be relationships between the EWs of C II
4267 \AA line and the rates orbital period increase and mass transfer in some
Algols. As the mass transfer rate increases the EW of the C II line decreases,
which indicates that accreted material has not been completely mixed yet in the
surface layers of the gainers. This result supports the idea of mixing as an
efficient process to remove the abundance anomaly built up by accretion.
Chemical evolution of the classical Algol-type systems may lead to constrains
on the initial masses of the less massive, evolved, mass-losing stars.Comment: 10 pages, 4 figures, accepted in MNRA
Transcription-replication conflicts: How they occur and how they are resolved
The frequent occurrence of transcription and DNA replication in cells results in many encounters, and thus conflicts, between the transcription and replication machineries. These conflicts constitute a major intrinsic source of genome instability, which is a hallmark of cancer cells. How the replication machinery progresses along a DNA molecule occupied by an RNA polymerase is an old question. Here we review recent data on the biological relevance of transcription-replication conflicts, and the factors and mechanisms that are involved in either preventing or resolving them, mainly in eukaryotes. On the basis of these data, we provide our current view of how transcription can generate obstacles to replication, including torsional stress and non-B DNA structures, and of the different cellular processes that have evolved to solve them
XRN2 Links Transcription Termination to DNA Damage and Replication Stress
We thank the Proteomics Core Facility. We thank Dr. Robert J. Crouch for providing us with GFP- and GFP-RNase H expression plasmids. We also thank Dr. Stephen H. Leppla for providing us with antibodies directed against RNA:DNA hybrids (R loops) (S9.6). We thank Novus Biologicals for generously providing XRN2 and Rrp45 antibodies. We also thank the members of the Boothman lab for critical reading of this manuscript.Author Summary Genomic instability is one of the primary causes of disease states, in particular cancer. One major cause of genomic instability is the formation of DNA double strand breaks (DSBs), which are one of the most dangerous types of DNA lesions the cell can encounter. If not repaired in a timely manner, one DSB can lead not only to cell death. If misrepaired, one DSB can lead to a hazardous chromosomal aberration, such as a translocation, that can eventually lead to cancer. The cell encounters and repairs DSBs that arise from naturally occurring cellular processes on a daily basis. A number of studies have demonstrated that aberrant structures that form during transcription under certain circumstances, in particular RNA:DNA hybrids (R loops), can lead to DSB formation and genomic instability, especially during DNA synthesis. Thus, it is important to understand how the cell responds and repairs transcription-mediated DNA damage in general and R loop-related DNA damage in particular. This paper both demonstrates that the XRN transcription termination factor links transcription and DNA damage, but also provides a better understanding of how the cell prevents transcription-related DNA damage.Yeshttp://www.plosgenetics.org/static/editorial#pee
Contributions to the flora of Tunceli (Turkey)
This study was carried out in Tunceli between 2011-2014 years. Research area is located in the IranoTuranian phytogeographic region and, according to Davis’ Grid system, in B7 square. During the
study 400 specimens have been collected. The identification of these samples resulted 55 families, 203
genera and 336 species. The analysis of the phytogeographic regions shows Irano-Turanian elements
85 (25.3 %), Mediterranean elements 23 (6.8 %), Europe-Siberian elements 14 (4.2 %), the ones with
wide or unknown distribution 214 (63.7 %). The number of endemic taxa is 18
Situation of mining/Mineral processing engineering education in Turkey: Statistical data and assessments [TÜRKIYE'DE MADEN/CEVHER HAZIRLAMA MÜHENDISLIGI EGITIMININ DURUMU: ISTATISTIKSEL VERILER ve DEGERLENDIRMELER]
26th International Mining Congress and Exhibition of Turkey, IMCET 2019 -- 16 April 2019 through 19 April 2019 -- -- 151960The history of modern mining engineering education in Turkey starting with Republican constitution has a history of about 100 years. Since the founding of the modern Republic of Turkey until the beginning of the 1980s, while just 5-6 faculty were existed, number increased rapidly and rise up to 25 after that date. In addition to this number, 7-8 faculties have also started second education term and reached up to unfavorable point in terms of registration quotas and number of graduates on yearly bases. Current situation can most clearly be defined as serious un-planning strategies on sectoral basis and in education steps since at least 25 years. Because of the serious low registration numbers, some secondary education departments have already closed down, but the same problem persists in most of the existing departments. The subject will be able to reach even more severe points in the coming years; therefore, urgently needs to produce emergency solutions together with departments and chambers of mining engineers. Within the scope of this paper, some perceptible evaluations will be able to make by compiling the data of the last 3 years of the existing Mining Engineering Departments. Copyright © IMCET 2019 International Mining Congress and Exhibition of Turkey. All rights reserved
Essential Oil Composition of Two Grammosciadium DC. Species, G. platycarpum (Boiss et Hausskn) Schischk and G. macrodon Boiss (Apiaceae), from Turkey
Purpose: To investigate and compare the essential oil composition of two Grammosciadium species
obtained by hydrodistillation
Methods: The essential oil of the aerial parts of two species was obtained by hydrodistillation and
analyzed by gas chromatography (GC) and gas chromatography - mass spectrometry (GC-MS).
Results: In G. platycarpum, twenty-seven compounds were identified representing 99.3 % of the total
oil. The major constituents of the oil were limonene (28.4 %), β-pinene (16.1 %), β-selinene (15.9 %), δ-
3-carene (11.2 %), α-farnesene (6.0 %) and p - cymene (4.7 %). The oil of G. macrodon contained
thirty-seven components representing 94.4 % of the total oil, with caryophyllene oxide (15.9 %),
germacrene - D (12.4 %), β-caryophyllene (11.5 %), δ-3 - carene (10.1 %) and cyclohexane (4.6 %) as
the main constituents.
Conclusion: The essential oil composition of G. macrodon was analysed for the first time, the most
abundant constituents being caryophyllene oxide, and cyclohexane
Gundelia glabra miller (Compositae) - an ignored taxon
When it was realized that Gundelia tournefortii L. (1753) consists of several clearly distinguishable taxa (Vitek et al. 2010) it was the next step to check all species and infra-specific taxa described later and treated as synonyms for their content
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