236 research outputs found
Uncommon branching pattern of the hepatic arteries in a living donor: a case report and brief literature review
Numerous variations of the hepatic arteries are common in surgical patients. We present a 35-year-old woman who was admitted to our department in order to assess possibility of becoming living donor. Preoperative computed tomography scan revealed anomalous branching pattern of the hepatic arteries. In this case right posterior sectoral artery has been given off by the greater pancreatic artery, left hepatic artery has been replaced by the artery arising from the left gastric artery and double segment 4 branches have been observed. To the best of our knowledge, this pattern has not been described in the literature, yet
Quantification of Biodiversity Related to the Active Protection of Grassland Habitats in the Eastern Lublin Region of Poland Based on the Activity of Soil Enzymes
This study focused on the impact of extensive sheep grazing on soil enzymatic activity in the grassland habitats of the Eastern Lublin region of Poland, situated within the ecological Natura 2000 network of: Kąty (PLH060010), Stawska Góra (PLH060018), and Zachodniowołyńska Dolina Bugu (PLH060035). This study involved soils under sheep grazing and soils in uncultivated areas (wasteland). Two-year study was conducted in 2 periods of each year: spring (before the start of sheep grazing) and autumn (after grazing). Beneficial effects were found for extensive grazing by sheep on soil enzymatic activity within each tested habitat. It is worth underlining that a clear stimulation of enzyme activity was detected already in the first year of observation. In the second year, the enzyme activity in the soils of habitats under sheep grazing was approximately 1.5 times higher than in the soils without grazing. The observed higher activity of the tested enzymes in soils under sheep grazing indicated the usefulness of studies on the enzymatic activity of soils as a sensitive indicator of soil response, such as observed here with the applied active system of biodiversity protection in the valuable natural grassland habitats of Natura 2000
Unusual features of long-range density fluctuations in glass-forming organic liquids : a Rayleigh and Rayleigh-Brillouin light scattering in study
A new feature of glass-forming liquids, i.e., long-range density fluctuations of the order of 100 nm, has been extensively characterized by means of static light scattering, photon correlation spectroscopy and Rayleigh-Brillouin spectroscopy in orthoterphenyl (OTP) and 1,1-di(4'-methoxy-5' methyl-phenyl)-cyclohexane (BMMPC). These long-range density fluctuations result in the following unusual features observed in a light scattering experiment. which are not described by the existing theories: (i) strong q-dependent isotropic excess Rayleigh intensity, (ii) additional slow component in the polarized photon correlation function, and (iii) high Landau-Placzek ratio. These unusual features are equilibrium properties of the glass-forming liquids and depend only on temperature, provided that the sample has been equilibrated long enough. The temperature-dependent equilibration times were measured for BMMPC and are about 11 orders of magnitude longer than the a process. It was found that the glass-forming liquid OTP may occur in two states: with and without long-range density fluctuations (''clusters"). We have characterized the two states by static and dynamic light scattering in the temperature range from T-g to T-g + 200 K. The relaxation times of the a process as well as the parameters of the Brillouin line are identical in both OTP with and without clusters. The a process (density fluctuations) in OTP was characterized by measuring either the polarized (VV) or depolarized (VH) correlation function, which are practically identical and a-independent. This feature, which is commonly observed in glass-forming liquids, is not fully explained by the existing theories
Sheep and Horse Grazing in a Large-Scale Protection Area and its Positive Impact on Chemical and Biological Soil Properties
This paper looks into the impact of free grazing by sheep and horses on the chemical and biological properties of soils in the partial protection zone of the Roztocze National Park. The study sampled three different types of pastureland in the area: pastures for sheep, horses and for combined grazing by sheep and horses. Compared to an ungrazed reference pasture, free grazing significantly stimulated the activity of enzymes which catalyze the transformation of organic matter (dehydrogenases, phosphatases and ureases) and it also positively influenced other chemical properties of the soils. Among the soils under free-grazing management, the pasture grazed to horses underwent the most advantageous changes in terms of the eco-chemical status of the soil
Experimental evidence of high pressure decoupling between charge transport and structural dynamics in a protic ionic glass-former
In this paper the relaxation dynamics of ionic glass-former acebutolol hydrochloride (ACB-HCl) is studied as a function of temperature and pressure by using dynamic light scattering and broadband dielectric spectroscopy. These unique experimental data provide the first direct evidence that the decoupling between the charge transport and structural relaxation exists in proton conductors over a wide T-P thermodynamic space, with the time scale of structural relaxation being constant at the liquid-glass transition (τα = 1000 s). We demonstrate that the enhanced proton transport, being a combination of intermolecular H+ hopping between cation and anion as well as tautomerization process within amide moiety of ACB molecule, results in a breakdown of the Stokes-Einstein relation at ambient and elevated pressure with the fractional exponent k being pressure dependent. The dT g /dP coefficient, stretching exponent βKWW and dynamic modulus E a /ΔV # were found to be the same regardless of the relaxation processes studied. This is in contrast to the apparent activation volume parameter that is different when charge transport and structural dynamics are considered. These experimental results together with theoretical considerations create new ideas to design efficient proton conductors for potential electrochemical applications
Acoustic and relaxation processes in supercooled o-ter-phenyl by optical-heterodyne transient grating experiment
The dynamics of the fragile glass-forming o-ter-phenyl is investigated by
time-resolved transient grating experiment with an heterodyne detection
technique in a wide temperature range. We investigated the dynamics processes
of this glass-former over more then 6 decades in time with an excellent
signal/noise. Acoustic, structural and thermal relaxations have been clearly
identify and measured in a time-frequency window not covered by previous
spectroscopic investigations. A detailed comparison with the density response
function, calculated on the basis of generalized hydrodynamics model, has been
worked out
Hydrodynamic Properties of Micelles of Dihydroxy Bile Salts: Sodium Taurodeoxycholate and Sodium Glycodeoxycholate
The dependence of the mutual translational diffusion coefficient
and the sedimentation coefficient on concentration of sodium
taurodeoxycholate in aqueous 0.15 m NaCl solutions at 25 °c indicates
a pronounced increase of the micelle size in the region
between the critical micelle concentration, equal to 0.00082 gcm-3,
and approximately ten times higher concentration. These results
were substantiated by the variation of the Rayleigh ratio of scattered
light. At concentrations of bile salt higher than about 0.008
gcm-3 the hydrodynamic and the thermodynamic interactions dominate
the measured quantities. The quasielastic light scattering
measurements provided the estimates of the polydispersity of the
micelles. The diffusion coefficient of sodium glycodeoxycholate
varied with concentration in a manner similar to that for the
taurine conjugate
Molecular excitation in the Interstellar Medium: recent advances in collisional, radiative and chemical processes
We review the different excitation processes in the interstellar mediumComment: Accepted in Chem. Re
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