Influence of HEMA content on the mechanical and bonding properties of experimental HEMA-added glass ionomer cements

The purpose of this study was to determine the influence of incrementally added uncured HEMA in experimental HEMA-added glass ionomer cement (HAGICs) on the mechanical and shear bond strength (SBS) of these materials. Increasing contents of uncured HEMA (10-50 wt.%) were added to a commercial glass ionomer cement liquid (Fuji II, GC, Japan), and the compressive and diametral tensile strengths of the resulting HAGICs were measured. The SBS to non-precious alloy, precious alloy, enamel and dentin was also determined after these surfaces were subjected to either airborne-particle abrasion (Aa) or SiC abrasive paper grinding (Sp). Both strength properties of the HAGICs first increased and then decreased as the HEMA content increased, with a maximum value obtained when the HEMA content was 20% for the compressive strength and 40% for the tensile strength. The SBS was influenced by the HEMA content, the surface treatment, and the type of bonding surface (

Supreme Court Rulings on Determining the Cartel End Date

Since the very nature of cartels is to operate in ways that are undisclosed and difficult to track, it is often a matter of heated dispute in courts as to when a cartel has ended or been abandoned. Moreover, the cartel duration is a critical issue because it affects not only the level of sanctions imposed, but also the damages amount sought against the cartelists. The Korean Supreme Court has issued several important rulings regarding this matter, but there still remain areas where further guidance and clarification would be beneficial. Thus, this article explores the relevant Korean Supreme Court rulings and concludes that it is time for the highest court to further articulate the legal test for determining the ending date of a cartel in an effort to eliminate legal uncertainty and establish clearer guidance for market participants

Burst Packet Loss Concealment Using Multiple Codebooks and Comfort Noise for CELP-Type Speech Coders in Wireless Sensor Networks

In this paper, a packet loss concealment (PLC) algorithm for CELP-type speech coders is proposed in order to improve the quality of decoded speech under burst packet loss conditions in a wireless sensor network. Conventional receiver-based PLC algorithms in the G.729 speech codec are usually based on speech correlation to reconstruct the decoded speech of lost frames by using parameter information obtained from the previous correctly received frames. However, this approach has difficulty in reconstructing voice onset signals since the parameters such as pitch, linear predictive coding coefficient, and adaptive/fixed codebooks of the previous frames are mostly related to silence frames. Thus, in order to reconstruct speech signals in the voice onset intervals, we propose a multiple codebook-based approach that includes a traditional adaptive codebook and a new random codebook composed of comfort noise. The proposed PLC algorithm is designed as a PLC algorithm for G.729 and its performance is then compared with that of the PLC algorithm currently employed in G.729 via a perceptual evaluation of speech quality, a waveform comparison, and a preference test under different random and burst packet loss conditions. It is shown from the experiments that the proposed PLC algorithm provides significantly better speech quality than the PLC algorithm employed in G.729 under all the test conditions

Effects of OH radicals on formation of Cu oxide and polishing performance in Cu Chemical Mechanical Polishing

The amount of OH radicals generated varied according to the complexing agent or Cu ion, and the accelerating effect of OH radicals on the rate of Cu oxide formation was found in acidic pH. When Cu I ions and oxalic acid were added to H2O2-based slurry, the decreases in etch and removal rates of Cu were observed because more generation of OH radicals resulted in the formation of thicker Cu oxide compared to additive-free slurry. Therefore, proper control of the formation and dissolution of Cu oxide led to an increase in etch and removal rates.This work was supported by the KOSEF through the Research Center for Energy Conversion and Storage (RCECS), Hanhwa Chemical, Ltd., and by the Institute of Chemical Processes (ICP) in Seoul National University

Astrocytoma in the Third Ventricle and Hypothalamus Presenting with Parkinsonism

Parkinsonism secondary to intracranial mass lesions usually results from compression or distortion of the basal ganglia. Secondary parkinsonism due to midbrain infiltration or compression is rare and generally associated with other neurologic signs caused by pyramidal tract and/or cranial nerve involvement. We report a case of 30-year-old woman in whom mild parkinsonism was the major clinical manifestation of an astrocytoma in the anterior third ventricle and hypothalamus. She underwent surgical resection, ventriculoperitoneal shunt and radiation therapy. All symptoms of parkinsonism were completely recovered 3 months after the treatment. Brain tumors can be manifested only by the symptoms of parkinsonism. This case emphasizes the significance of neuroimaging in the evaluation of parkinsonism

Coordinated Beamforming with Limited BS Cooperation for Multicell Multiuser MIMO Broadcast Channel

The capacity of downlink multi-input multi-output (MIMO) systems is significantly limited by inter-cell co-channel interference (CCI). Improving the erformance of cell edge users who suffers strong inter-cell CCI is still a crucial issue. In this paper, coordinated beamforming (CBF)lgorithm for multicell multiuser MIMO system is proposed to cope with the presence of intel-cell CCI. In multicell environment with MIMO channel, limited base station (BS) cooperation is considered to design optimal transmit and receive beamformers which make interference-free at the receiver. Simulation results show that the proposed algorithms can improve the capacity of cell edge user effectively as well as the overall system capacity for multiuser multicell MIMO system