3,841 research outputs found
Determination of Boron Diffusion Coefficients in Wood
The unsteady-state diffusion of boron through southern pine (Pinus spp.) was investigated at various moisture contents, temperatures, and treatment conditions. The fastest rates of diffusion were observed in the longitudinal direction, followed by the radial and the tangential directions. The diffusion rate increased with time in all directions. The longitudinal diffusion rate increased rapidly with moisture content (MC), while a slow increase in the radial diffusion rate was observed at MCs above 90%. Moisture conlent did not affect the rate of tangential diffusion within the range of MCs in this study (70-110%). The effect of temperature on boron diffusion rates was more pronounced than the effect of MC. The diffusion rate increased with temperature, although slight direction-dependent differences were observed. A repeated dip-treatment increased the rate of diffusion in the tangential direction, but only small differences were found in the longitudinal and the radial directions. No other data were found in the literature for comparison.Average values of the diffusion coefficients were calculated to predict the concentration profile of boron in wood under various conditions. The longitudinal diffusion coefficients were 10 to 20 times larger than the radial diffusion coefficients, and the radial diffusion coefficients were two to four times larger than the tangential diffusion coefficients. The use of the average boron diffusion coefficients caused some differences between real and predicted values in the early stages of diffusion, but the potential for practical use was demonstrated
Effect of lesimarin against thioacetamide-induced liver cirrhosis in rat
Liver cirrhosis is one of chronic liver diseases with high disability and mortality accompanying fibrosis, hepatocyte damage, and liver dysfunction. In this study, the hepatoprotective and the antifibrotic properties of lesimarin(lecithin - silymarin - Artemisia messerschmitiana Besser(AMB) extract complex at 11:3:6 ratio) on rat hepatic fibrosis induced by thioacetamide (TAA) was investigated. Rats were divided into seven groups: control, lesimarin, TAA, TAA+lesimarin, TAA+lecithin, TAA+silymarin, TAA+AMB. Rats were administered with TAA at a dose of 200 mg/kg body weight intraperitoneally twice a week for three months. Lesimarin, lecithin, silymarin and AMB were administered at a dose of 1.0, 1.0, 0.5, 1.0g/kg body weight orally daily for three months, respectively. TAA administration resulted in hepatic fibrosis, significant decrease in body weight, albumin level and A/G ratio and increase in plasma transaminase, GGT(γ-glutamyltransferase) and ALP(alkaline phosphatase) activities as well as hepatic hydroxyproline content, which were attenuated by lesimarin administration. Lesimarin was found to decrease AST, ALT and GGT, ALP and bilirubin, hydroxyproline levels and increase albumin level and A/G ratio and its effect is more prominent than those of individual constituents. These results suggest this new drug, lesimarin, might be a promising drug to be used for chronic liver diseases
Investigating cortico-subcortical circuits during auditory sensory attenuation: A combined magnetoencephalographic and dynamic causal modeling study
Sensory attenuation refers to the decreased intensity of a sensory percept when a sensation is self‐generated compared with when it is externally triggered. However, the underlying brain regions and network interactions that give rise to this phenomenon remain to be determined. To address this issue, we recorded magnetoencephalographic (MEG) data from 35 healthy controls during an auditory task in which pure tones were either elicited through a button press or passively presented. We analyzed the auditory M100 at sensor‐ and source‐level and identified movement‐related magnetic fields (MRMFs). Regression analyses were used to further identify brain regions that contributed significantly to sensory attenuation, followed by a dynamic causal modeling (DCM) approach to explore network interactions between generators. Attenuation of the M100 was pronounced in right Heschl's gyrus (HES), superior temporal cortex (ST), thalamus, rolandic operculum (ROL), precuneus and inferior parietal cortex (IPL). Regression analyses showed that right postcentral gyrus (PoCG) and left precentral gyrus (PreCG) predicted M100 sensory attenuation. In addition, DCM results indicated that auditory sensory attenuation involved bi‐directional information flow between thalamus, IPL, and auditory cortex. In summary, our data show that sensory attenuation is mediated by bottom‐up and top‐down information flow in a thalamocortical network, providing support for the role of predictive processing in sensory‐motor system
Dual quadratic differentials and entire minimal graphs in Heisenberg space
We define holomorphic quadratic differentials for spacelike surfaces with
constant mean curvature in the Lorentzian homogeneous spaces
with isometry group of dimension 4, which are dual to
the Abresch-Rosenberg differentials in the Riemannian counterparts
, and obtain some consequences. On the one hand, we
give a very short proof of the Bernstein problem in Heisenberg space, and
provide a geometric description of the family of entire graphs sharing the same
differential in terms of a 2-parameter conformal deformation. On the other
hand, we prove that entire minimal graphs in Heisenberg space have negative
Gauss curvature.Comment: 19 page
Full Counting Statistics of Superconductor--Normal-Metal Heterostructures
The article develops a powerful theoretical tool to obtain the full counting
statistics. By a slight extension of the standard Keldysh method we can access
immediately all correlation functions of the current operator. Embedded in a
quantum generalization of the circuit theory of electronic transport, we are
able to study the full counting statistics of a large class of two-terminal
contacts and multi-terminal structures, containing superconductors and normal
metals as elements. The practical use of the method is demonstrated in many
examples.Comment: 35 pages, contribution to "Quantum Noise", ed. by Yu.V. Nazarov and
Ya.M. Blanter, minor changes in text, references adde
Calcium Uptake and Release through Sarcoplasmic Reticulum in the Inferior Oblique Muscles of Patients with Inferior Oblique Overaction
We characterized and compared the characteristics of Ca2+ movements through the sarcoplasmic reticulum of inferior oblique muscles in the various conditions including primary inferior oblique overaction (IOOA), secondary IOOA, and controls, so as to further understand the pathogenesis of primary IOOA. Of 15 specimens obtained through inferior oblique myectomy, six were from primary IOOA, 6 from secondary IOOA, and the remaining 3 were controls from enucleated eyes. Ryanodine binding assays were performed, and Ca2+ uptake rates, calsequestrins and SERCA levels were determined. Ryanodine bindings and sarcoplasmic reticulum Ca2+ uptake rates were significantly decreased in primary IOOA (p<0.05). Western blot analysis conducted to quantify calsequestrins and SERCA, found no significant difference between primary IOOA, secondary IOOA, and the controls. Increased intracellular Ca2+ concentration due to reduced sarcoplasmic reticulum Ca2+ uptake may play a role in primary IOOA
Umbilical Arterial Blood Gas and Perinatal Outcome in the Second Twin according to the Planned Mode of Delivery
Purpose: To compare umbilical arterial gas parameters in the second twin of twin pregnancies according to the mode of deliver
Modeling the Fate and Transport of Malathion in the Pagsanjan-Lumban Basin, Philippines
Exposure to highly toxic pesticides could potentially cause cancer and disrupt the development of vital systems. Monitoring activities were performed to assess the level of contamination; however, these were costly, laborious, and short-term leading to insufficient monitoring data. However, the performance of the existing Soil and Water Assessment Tool (SWAT model) can be restricted by its two-phase partitioning approach, which is inadequate when it comes to simulating pesticides with limited dataset. This study developed a modified SWAT pesticide model to address these challenges. The modified model considered the three-phase partitioning model that classifies the pesticide into three forms: dissolved, particle-bound, and dissolved organic carbon (DOC)-associated pesticide. The addition of DOC-associated pesticide particles increases the scope of the pesticide model by also considering the adherence of pesticides to the organic carbon in the soil. The modified SWAT and original SWAT pesticide model was applied to the Pagsanjan-Lumban (PL) basin, a highly agricultural region. Malathion was chosen as the target pesticide since it is commonly used in the basin. The pesticide models simulated the fate and transport of malathion in the PL basin and showed the temporal pattern of selected subbasins. The sensitivity analyses revealed that application efficiency and settling velocity were the most sensitive parameters for the original and modified SWAT model, respectively. Degradation of particulate-phase malathion were also significant to both models. The rate of determination (R2) and Nash-Sutcliffe efficiency (NSE) values showed that the modified model (R2 = 0.52; NSE = 0.36) gave a slightly better performance compared to the original (R2 = 0.39; NSE = 0.18). Results from this study will be able to aid the government and private agriculture sectors to have an in-depth understanding in managing pesticide usage in agricultural watersheds
- …