978 research outputs found
Hemodynamic and inotropic effects of endothelin-1 in vivo
Endothelin-1 (ET-1) is known to have strong vasoactive properties. Contradictory results have been reported with regard to its inotropic effects. This study examined the dose-dependent (500, 1000, 2500, 5000 and 10,000 ng ET-1/kg vs. NaCl controls) hemodynamic and inotropic effects of ET-1 in 53 open-chest rats during and after a 7-min infusion. Besides measurements in the intact circulation the myocardial function was examined by isovolumic registrations independent of peripheral vascular effects. A transient ET-1 induced (500, 1000, 2500, 5000 ng ET-1/kg) decrease of the left ventricular systolic pressure (LVSP) and the mean aortic pressure (AoPmean) was followed by a dose-related rise of these pressures (LVSP: -1%, -1%, +8%, +16% vs. preinfusion values; AoPmean: -11%, +9%, +39%, +52%). Heart rate (HR) was not influenced by ET-1. Due to the dose-dependent decrease of the stroke volume (SV) the cardiac output (CO) was reduced (CO: -8%, -23%, -40%, -50%). After an initial vasodilatation ET-1 elevates the total peripheral resistance (TPR: -1%, +49%, +139%, +215%) dose-dependently. 10,000 ng ET-1/kg was a lethal dose resulting in cardiac failure within minutes (low output). Since the maximum of the isovolumic LVSP (peak LVSP) and the corresponding dP/dtmax (peak dP/dtmax) were unchanged under ET-1, the isovolumic measurements do not indicate a positive inotropic effect of ET-1 in vivo in contrast to published results of in vitro experiments. It may be possible that a direct positive inotropic effect of ET-1 observed in in vitro studies is counterbalanced in vivo by an indirect negative inotropic effect due to the coronary-constrictive effect of ET-1
Ectomycorrhizal influence on the dynamics of sesquiterpene release by Tricholoma vaccinum
Tricholoma vaccinum is an ectomycorrhizal basidiomycete with high host specificity. The slow-growing fungus is able to produce twenty sesquiterpenes, including α-barbatene, sativene, isocaryophyllene, α-cuprenene, β-cedrene, ß-copaene, 4-epi-α-acoradiene, and chamigrene in axenic culture. For the three major compounds, Δ(6)-protoilludene, β-barbatene, and an unidentified oxygenated sesquiterpene (m/z 218.18), changed production during co-cultivation with the ectomycorrhizal partner tree, Picea abies, could be shown with distinct dynamics. During the mycorrhizal growth of T. vaccinum–P. abies, Δ(6)-protoilludene and the oxygenated sesquiterpene appeared at similar times, which warranted further studies of potential biosynthesis genes. In silico analyses identified a putative protoilludene synthesis gene, pie1, as being up-regulated in the mycorrhizal stage, in addition to the previously identified, co-regulated geosmin synthase, ges1. We therefore hypothesize that the sesquiterpene synthase pie1 has an important role during mycorrhization, through Δ(6)-protoilludene and/or its accompanied oxygenated sesquiterpene production
Real-time Monitoring of High-speed Spindle Operations Using Infrared Data Transmission
AbstractHigh-performance cutting is carried out with high cutting and feed speeds. Particularly, the use of heavy cutting tools (e.g. in planing machines), it is important to monitor the clamping and balance condition of the mounted tool, as well as the process forces. Therefore, a real-time monitoring system for high-speed operations based on the IrDA protocol was developed. It could be shown that infrared data transmission systems allow shorter reaction times compared to conventional wireless LAN applications. The presented monitoring system provides a reaction time of 7.14 ms at a bandwidth of 42.5 kHz and a data rate of 4.1 MBit/s
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The influence of postpartum PTSD on breastfeeding: A longitudinal population-based study.
BACKGROUND: In most Western countries, breastfeeding rates are lower than what is recommended by the World Health Organization. Depression has been shown to influence breastfeeding outcomes; however, there is very little research on the role of postpartum posttraumatic stress disorder (PTSD). This study examined to what extent maternal postpartum PTSD predicted breastfeeding initiation, exclusive breastfeeding during the first 6 months, and continuation up to 1 and 2 years.
METHODS: The study is part of the large, population-based Akershus Birth Cohort. Data from the hospital's birth record and questionnaire data from 8 weeks and 2 years postpartum were used (n = 1480). All breastfeeding variables significantly correlated with postpartum PTSD were entered into stepwise logistic regression analyses.
RESULTS: Although most mothers (97.1%) initiated breastfeeding, considerably fewer adhered to the World Health Organization's breastfeeding guidelines about exclusive breastfeeding during the first 6 months (13.4%) or continued breastfeeding for 12 or 24 months postpartum (37.7% and 4.2%, respectively). Even after adjustment for important confounding variables, maternal postpartum PTSD was significantly associated with not initiating breastfeeding (aOR 5.98 [95% CI 1.79-19.97]). Postpartum PTSD was also significantly related to not continuing breastfeeding up to 12 months, although this association did not hold after adjusting for confounding variables.
CONCLUSION: Identifying women at risk of not initiating breastfeeding is crucial to prevent a negative influence on infant development and the development of the mother-infant bond. Early screening and treatment of women at risk of developing postpartum PTSD might be a way forward
Star Formation Activity in the Galactic HII Complex S255-S257
We present results on the star-formation activity of an optically obscured
region containing an embedded cluster (S255-IR) and molecular gas between two
evolved HII regions S255 and S257. We have studied the complex using optical,
near-infrared (NIR) imaging, optical spectroscopy and radio continnum mapping
at 15 GHz, along with Spitzer-IRAC results. It is found that the main exciting
sources of the evolved HII regions S255 and S257 and the compact HII regions
associated with S255-IR are of O9.5 - B3 V nature, consistent with previous
observations. Our NIR observations reveal 109 likely young stellar object (YSO)
candidates in an area of ~ 4'.9 x 4'.9 centered on S255-IR, which include 69
new YSO candidates. Our observations increased the number of previously
identified YSOs in this region by 32%. To see the global star formation, we
constructed the V-I/V diagram for 51 optically identified IRAC YSOs in an area
of ~ 13' x 13' centered on S255-IR. We suggest that these YSOs have an
approximate age between 0.1 - 4 Myr, indicating a non-coeval star formation.
Using spectral energy distribution models, we constrained physical properties
and evolutionary status of 31 and 16 YSO candidates outside and inside the gas
ridge, respectively. The models suggest that the sources associated within the
gas ridge are of younger population (mean age ~ 1.2 Myr) than the sources
outside the gas ridge (mean age ~ 2.5 Myr). The positions of the young sources
inside the gas ridge at the interface of the HII regions S255 and S257, favor a
site of induced star formation.Comment: 46 pages, 14 figures, 5 tables. Accepted for publication in The
Astrophysical Journa
Orbital and physical parameters of eclipsing binaries from the ASAS catalogue -- I. A sample of systems with components' masses between 1 and 2 M
We derive the absolute physical and orbital parameters for a sample of 18
detached eclipsing binaries from the \emph{All Sky Automated Survey} (ASAS)
database based on the available photometry and our own radial velocity
measurements. The radial velocities (RVs) are computed using spectra we
collected with the 3.9-m Anglo-Australian Telescope and its \emph{University
College London Echelle Spectrograph} and the 1.9-m SAAO Radcliffe telescope and
its \emph{Grating Instrument for Radiation Analysis with a Fibre Fed Echelle}.
In order to obtain as precise RVs as possible, most of the systems were
observed with an iodine cell available at the AAT/UCLES and/or analyzed using
the two-dimensional cross-correlation technique (TODCOR). The RVs were measured
with TODCOR using synthetic template spectra as references. However, for two
objects we used our own approach to the tomographic disentangling of the binary
spectra to provide observed template spectra for the RV measurements and to
improve the RV precision even more. For one of these binaries, AI Phe, we were
able to the obtain an orbital solution with an RV of 62 and 24 m s
for the primary and secondary respectively. For this system, the precision in
is 0.08%. For the analysis, we used the photometry available in
the ASAS database. We combined the RV and light curves using PHOEBE and JKTEBOP
codes to obtain the absolute physical parameters of the systems. Having precise
RVs we were able to reach 0.2 % precision (or better) in masses in
several cases but in radii, due to the limited precision of the ASAS
photometry, we were able to reach a precision of only 1% in one case and 3-5 %
in a few more cases. For the majority of our objects, the orbital and physical
analysis is presented for the first time.Comment: 16 pages, 2 figures, 6 tables in the main text, 1 table in appendix,
to appear in MNRA
Genetic Survey of Psilocybe Natural Products
Psilocybe magic mushrooms are best known for their main natural product, psilocybin, and its dephosphorylated congener, the psychedelic metabolite psilocin. Beyond tryptamines, the secondary metabolome of these fungi is poorly understood. The genomes of five species ( P. azurescens , P. cubensis , P. cyanescens , P. mexicana , and P. serbica ) were browsed to understand more profoundly common and species‐specific metabolic capacities. The genomic analyses revealed a much greater and yet unexplored metabolic diversity than evident from parallel chemical analyses. P. cyanescens and P. mexicana were identified as aeruginascin producers. Lumichrome and verpacamide A were also detected as Psilocybe metabolites. The observations concerning the potential secondary metabolome of this fungal genus support pharmacological and toxicological efforts to find a rational basis for yet elusive phenomena, such as paralytic effects, attributed to consumption of some magic mushrooms
The {\eta}'-carbon potential at low meson momenta
The production of mesons in coincidence with forward-going
protons has been studied in photon-induced reactions on C and on a
liquid hydrogen (LH) target for incoming photon energies of 1.3-2.6 GeV at
the electron accelerator ELSA. The mesons have been identified
via the decay
registered with the CBELSA/TAPS detector system. Coincident protons have been
identified in the MiniTAPS BaF array at polar angles of . Under these kinematic constraints the
mesons are produced with relatively low kinetic energy (
150 MeV) since the coincident protons take over most of the momentum of the
incident-photon beam. For the C-target this allows the determination of the
real part of the -carbon potential at low meson momenta by
comparing with collision model calculations of the kinetic energy
distribution and excitation function. Fitting the latter data for
mesons going backwards in the center-of-mass system yields a potential depth of
V = (44 16(stat)15(syst)) MeV, consistent with earlier
determinations of the potential depth in inclusive measurements for average
momenta of 1.1 GeV/. Within the experimental
uncertainties, there is no indication of a momentum dependence of the
-carbon potential. The LH data, taken as a reference to check
the data analysis and the model calculations, provide differential and integral
cross sections in good agreement with previous results for
photoproduction off the free proton.Comment: 9 pages, 13 figures. arXiv admin note: text overlap with
arXiv:1608.0607
Tips to Advance Business Writing Skills at EFL Classes (Through the Example of "Letter of Complaint")
Writing is a creative communicative skill to express thoughts. It is cognitively complex, requires much practice and is best learned through experience. Writing is one of the most challenging, time-consuming tasks in acquiring a foreign language. To improve students’ writing skills and accuracy, a teacher should encourage writing-thinking, provide instructions and examples of good writing in the target language, and give feedback focusing both on error correction (cohesion) and organization of writing (clarity, idea development, coherence). This paper explores difficulties of the development of business writing skills and gives recommendations on writing a letter of complaint at English as a foreign language classes
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