High affinity hormone binding to the extracellular N-terminal exodomain of the follicle-stimulating hormone receptor is critically modulated by exoloop 3

The human follicle-stimulating hormone receptor (FSH-R) consists of two distinct domains of >330 amino acids, the N-terminal extracellular exodomain and membrane-associated endodomain. The exodomain alone binds hormone with high affinity, whereas the endodomain is the site of receptor activation. Coordination of these two domains is essential for successful hormone action but little is known about their functional and structural relationship. In this communication, we report that exoloop 3 of FSH-R constrains follicle-stimulating hormone binding to the exodomain. When the FSH-R exodomain was prepared by truncating its endodomain, the hormone binding affinity of the exodomain was slightly improved, compared with the wild type receptor. The binding affinity was further improved by >3-fold when the exodomain was attached to the membrane-associated domain of CD8. These results suggest that the FSH-R endodomain attenuates hormone binding at the exodomain. As a first step to test this hypothesis, the 11 amino acids except Ala589 of exoloop 3 were individually substituted with Ala. Ala substitution for Leu583 or Ile584 improved the hormone binding affinity by 4-6-fold while totally abolishing cAMP induction, indicating an inverse relationship. The Ala substitution for Lys580 or Pro582 had a similar trend but to a lesser extent. This significant improvement in the binding affinity suggests that the four residues at the N-terminal region of exoloop 3 interact with the exodomain and constrain the hormone binding in the wild type receptor. This effect is specific since substitutions for other than the 4 residues did not improve the hormone binding affinity. Computer modeling shows that the 4 residues can be positioned on one side of exoloop 3. This result and the apparent inverse relationship of hormone binding and cAMP induction suggest that these two essential functions may work against each other. Therefore, hormone binding might be compromised to preserve cAMP inducibility while maintaining a reasonably high, but below maximum, binding affinity.     

Motion based object tracking with mobile camera

An efficient algorithm which detects and tracks a moving object is proposed. The global motion energy caused by camera movement is eliminated by finding the maximal matching position with the cross-correlation value between two consecutive frames using the spiral scanning technique. The region of a moving object is segmented exactly by combining the results of the temporal derivatives and edge map from one image, and the actual centroid of the moving object is determined as the mid-point of the cumulative distribution of the projection profile of the region     

Perioperative specific management of blood volume loss in craniosynostosis surgery

Accurate assessment and replacement of blood loss and fluid-electrolyte deficit during craniosynostosis repair is difficult owing to patient size and the diversity of surgical technique. Forty-three patients undergoing primary craniosynostosis repair over a 10-year period were studied retrospectively to determine blood loss and fluid deficit and to assess blood transfusion practices during both intraoperative and postoperative periods. Blood loss was calculated on the basis of estimated red cell mass (ERCM) and fluid-electrolyte imbalance was investigated with blood samplings. Blood transfusion was considered appropriate if the postoperative or posttransfusion ERCM was within 12% of the preoperative value. Estimated fluid requirement (EFR) was used in 4 ml kg(-1) h(-1) except for neonates. Intraoperatively, 80% of all patients were appropriately managed with respect to blood transfusion and EFR. Postoperatively only 20% of the patients receiving transfusions were transfused appropriately. In 23.3% of these patients (10/43) unexpected respiratory distress developed immediately after their recovery from the anesthesia. With the measurement of estimated blood volume and allowable blood loss, appropriate transfusion could be achieved for the successful treatment of the primary craniosynostosis.     

High-performance simulations of turbulent boundary layer flow using Intel Xeon Phi many-core processors

The Journal of Supercomputing - Direct numerical simulations (DNS) of turbulent flows have increasing importance because they not only provide fundamental understanding of turbulent flows but also...     

Synthesis of silver/polymer colloidal composites from surface-functional porous polymer microspheres

This study presents a different colloidal silver (Ag)/polymer system where Ag nanoparticles are deposited uniformly onto surface-functional porous poly(ethylene glycol dimethacrylate-co-acrylonitrile) (poly(EGDMA-co-AN)) microspheres. The formation and morphology of the composite microspheres were characterized from electron microscopy and X-ray diffraction analyses. The significance of the present report is that owing to the high affinity between Ag and nitrile group (CN) on the large surface of the microspheres, the Ag nanoparticles having a face-centered cubic phase were incorporated evenly into the deep pores of the microspheres with fine size and size distribution. In the preservation test, the Ag/poly(EGDMA-co-AN) composite microspheres obtained showed an excellent anti-bacterial performance, elucidating a high applicability for a new preservative.     

Dynamics of the wet-end section in paper mills

A model representing the wet-end section of a paper mill has been developed to characterize its dynamic behavior during the grade change. The model is based on the mass balance relationships written for the simplified wetend white water network. From the linearization of the dynamic model, higher-order Laplace transfer functions were obtained followed by the reduction procedure to give simple lower-order models in the form of 1^st-order or 2^nd-order plus dead times. The dynamic response of the wet-end is influenced both by the white water volume and by the level of wire retention. Effects of key manipulated variables such as the thick stock flow rate, the ash flow rate and the retention aid flow rate on the major controlled variables were analyzed by numerical simulations. The simple dynamic model developed in the present study can be effectively used in the operation and control. This paper is dedicated to Professor Se Ki Moon on the occasion of his retirement from Hanyang University.     

The Effect of Aluminum Ions on the DC Etching of Aluminum Foil

A study has been made of the electrochemical etching of 99.99% aluminum foils at a current density of 50 mA cm^–2in AlCl₃–HCl solutions (1 m Cl^–) at 80 °C. The solutions were made by dissolving metallic aluminum into 1m HCl solution, to give a Cl^– concentration of 1 m. The number density of etch tunnels and the homogeneity of tunnel length decreased, and the mean pit size and its standard deviation increased with increasing Al³⁺ concentration. The results were discussed based on potential transients at a current density of 50 mA cm^–2, current–potential curves at a scan rate of 10 m Vs^–1 and electrochemical impedance spectra.     

Rheological characteristics of mesophase pitch

Rheological characteristics of two pretreated petroleum pitches, during their transformation to mesophase, have been studied by using rotalional viscometer. Simultaneously, the formation, growth, coalescence of mesuphase spheres, and the alignment of coalesced mesophase were observed by Hot-Stage-Cinema-Microscope, discussed with the results of viscosity change and the Q.I. content. It is found that both pretreated pitches were Newtonian fluids at low temperature, but behaved pseudoplastics as increase of mesophase content above 390C. Shear thinning behaviour was also apparent in the shear rate range of 1.9–20 sec⁻¹ at temperature above 390C. The apparent viscosity-temperature curves of this pyrolysed pitches were much affected by the pretreatment conditions.     

Effect of water pretreatment on CO<Subscript>2</Subscript> capture using a potassium-based solid sorbent in a bubbling fluidized bed reactor

A bubbling fluidized bed reactor was used to study CO₂ capture from flue gas by using a potassium-based solid sorbent, sorbKX35 which was manufactured by the Korea Electric Power Research Institute. A dry sorbent, sorbKX35, consists of K₂CO₃ for absorption and supporters for mechanical strength. To increase initial CO₂ removal, some amount of H₂O was absorbed in the sorbent before injecting simulated flue gas. It was possible to achieve 100% CO₂ removal for more than 10 minutes at 60°C and a residence time of 2 s with H₂O pretreatment. When H₂O pretreatment time was long enough to convert K₂CO₃ of sorbKX35 into K₂CO₃ · 1.5H₂O, CO₂ removal was excellent. The results obtained in this study can be used as basic data for designing and operating a large scale CO₂ capture process with two fluidized bed reactors. This work was presented at the 6 ^th Korea-China Workshop on Clean Energy Technology held at Busan, Korea, July 4–7, 2006.     

Catalytic characteristics of various rubber-reinforcing carbon blacks in decomposition of methane for hydrogen production

Carbon black has recently been reported to act as an effective catalyst for methane decomposition and to exhibit stable catalytic behavior despite carbon deposition, and thus it can be used for CO₂-free production of hydrogen from natural gas. In this work, various carbon blacks with different primary particle size were investigated with respect to methane decomposition under atmospheric pressure from 1123 to 1223 K. Catalytic characteristics, such as activity, activation energy and reaction order, were investigated and compared. It was observed that with decreasing primary particle size (or increasing specific surface area), the specific activity increased and the activation energy decreased. The reaction orders for various pelletized, rubber-reinforcing carbon blacks were 0.6–0.7, about the same regardless of the primary particle size, while they were near 1 for fluffy carbon blacks. Fluffy carbon black showed higher activity and activation energy than the pelletized carbon black of the same primary particle size. Changes of the surface morphology during carbon deposition were observed by TEM. Variations of the number of active sites were discussed in regard of the primary particle size, carbon deposition and binder. The presence of different types of active sites was also suggested.