Object substitution masking: When does mask preview work?

When a target is enclosed by a 4-dot mask that persists after the target disappears, target identification is worse than it is when the mask terminates with the target. This masking effect is attributed to object substitution masking (OSM). Previewing the mask, however, attenuates OSM. This study investigated specific conditions under which mask preview was, or was not, effective in attenuating masking. In Experiment 1, the interstimulus interval (ISI) between previewed mask offset and target presentation was manipulated. The basic preview effect was replicated; neither ISI nor preview duration influenced target identification performance. In Experiment 2, mask configurations were manipulated. When the mask configuration at preview matched that at target presentation, the preview effect was replicated. New evidence of ineffective mask preview was found: When the two configurations did not match, performance declined. Yet, when the ISI between previewed mask offset and target presentation was removed such that the mask underwent apparent motion, preview was effective despite the configuration mismatch. An interpretation based on object representations provides an excellent account of these data. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ozonation of complex industrial park wastewater: effects on the change of wastewater characteristics

BACKGROUND: Ozonation of complex industrial park wastewater was carried out in a semi‐batch reactor. The variation of wastewater characteristics was evaluated based on the analysis of 5‐day biochemical oxygen demand (BOD₅) concentration, BOD₅/chemical oxygen demand (COD) ratio, COD fractionation, and dissolved organic carbon (DOC) molecular size distribution before and after ozonation. RESULTS: The experimental results indicated that low efficiency of COD removal with increasing tendency of BOD₅ concentration generally appeared after ozonation. Also, the BOD₅/COD ratio increased from an initial of 0.27 to a maximum of 0.38. The COD fractionation tests revealed that most of the inert soluble COD was transformed to biodegradable soluble COD at 30 min of reaction time. Additionally, the DOC molecular size distribution tests showed that the fraction larger than 500 kDa was significantly decreased and the fraction smaller than 2 kDa was increased when the reaction time was prolonged to 240 min. CONCLUSION: This study verified that partial oxidation of the complex industrial park wastewater by ozonation could enhance wastewater biodegradability. The biodegradability enhancement was primarily because the inert soluble COD fraction was converted to the biodegradable soluble COD and the high molecular weight fraction of DOC was shifted toward the low molecular weight fraction. Copyright © 2009 Society of Chemical Industry     

Development of a PCR assay for the detection of nifH and nifD genes in indigenous photosynthetic bacteria

Molybdenum (Mo) nitrogenases consist of two components: dinitrogenase reductase (encoded by nifH) and the dinitrogenase or MoFe protein (encoded by nifDK). Nitrogenase enzyme of photosynthetic bacteria is responsible for hydrogen production. Therefore, primers were designed for the nitrogenase gene only. In this study, two primers (ND and NH) were designed after comparative genomic analysis of nifH and nifD gene sequences from public databases. The designed primers were used for the amplification of nifH and nifD genes to detect nitrogenase genes in photosynthetic bacteria. Initial detection was done using a monoplex Polymerase Chain Reactions (PCRs) followed by optimization of the PCR protocols. Subsequently, a duplex PCR was designed for amplification and detection of nifH and nifD genes in indigenous photosynthetic bacteria. Evaluation of the duplex PCR on six samples isolated from Palm Oil Mill Effluent (POME) showed that only four isolates contained both the nifH and nifD genes, indicating that these isolates were potential hydrogen-producing bacteria. PCR detection provides a rapid and efficient pre-identification of potential photosynthetic bacterial hydrogen producers.     

Tone interference in VSAT spectrum

This paper investigates the problem of tone interference within the very small aperture terminal (VSAT) binary phase-shift keying (BPSK) signal spectrum. The degree of performance degradation of a VSAT link in the presence of a tone interference is discussed. A simple theoretical analysis is derived, and its validity is verified by experimental measurements performed using a standard commercial VSAT modem measurement setup     

Forward-link BER analysis of asynchronous cellular DS-CDMA overNakagami-faded channels using combined PDF approach

A closed-form conditional probability density function (PDF) of the Nakagami-faded-interference-to-signal power ratio, given the exact location of the tagged mobile, is derived for integer values of Nakagami (1960) fade parameter m. The conditional PDF, whose coefficients can be computed efficiently in a recursive manner, significantly reduces the computational complexity of forward-link bit error rate (BER) evaluation of a direct-sequence code-division multiple-access (DS-CDMA) cellular system over a fading channel, BER curves reveal that the performance improvement of increasing m is not significant for m>4. Performance results for noninteger values of m can be estimated using the linear interpolation technique. With the derived BER expressions, a more realistic cellular model that takes into account the effects of nonidentical m and path-loss exponent is proposed and analyzed. By substituting appropriate values of m, the BER performance for a class of fading distributions such as Rayleigh and Ricean fading can be evaluated or approximated. In particular, the Nakagami approximation may be treated as a tight lower bound to the corresponding mathematically involved Ricean case     

The Marei Ika Daigaku (Syonan Medical College) during the Japanese occupation of Singapore (1942-1945)

During the Japanese Occupation of Singapore (1942-1945), Singapore was renamed Syonan (or Syonanto). The Japanese Military Administration established The Medical College on 27 April 2603 (1943) and it was known as The Marei Ika Daigaku or Syonan Medical College. It was sited at the Tan Tock Seng Hospital (Hakua Byoin). The Ika Daigaku relocated to the General Hospital, Malacca in February 2604 (1944) where it functioned till the end of the Japanese Occupation in September 1945. About 200 students from Singapore, Malaya, Sumatra and Java attended the Syonan Medical College; the students were taught mainly Japanese language and culture.     

Region-Reaching Control of Robots

In conventional setpoint control problem of robots, the desired position is specified as a point. However, it is interesting to observe from most human reaching movements that the desired targets are regions rather than points. In fact, when the desired region is specified arbitrarily small, it reduces to a point. In this paper, we propose a new control concept called region reaching control for robots. In this new control concept, the desired objective can be specified as a region instead of a point. Since the desired region can be specified arbitrarily small, the region control concept is also a generalization of setpoint control problem. Experimental results are presented to illustrate the performance of the proposed controllers.     

Fabrication of Embedded Microstructures Via Lamination of Thick Gel‐Casted Ceramic Layers

This article describes a new approach to fabricate various embedded ceramic microstructures. Design geometries of the microstructures are replicated onto a soft reusable polydimethylsiloxane (PDMS) mold. Rapid consolidation of ceramic suspension on the molds using gel‐casting technique produces structured ceramic layers. 85% aqueous glycerol solution has been identified as suitable adhesive agent to laminate the ceramic layers. Capability of the approach in fabricating embedded microstructures of 3‐dimensional and aspect ratio as high as 20 and 50 has been demonstrated. Ceramic microthruster and Y‐shaped microfluidic reactor are fabricated using this new approach to show its potential to construct various ceramic microdevices.     

Rapid Quantification of Live Cell Receptors Using Bioluminescence in a Flow‐Based Microfluidic Device

The number of receptors expressed by cells plays an important role in controlling cell signaling events, thus determining its behaviour, state and fate. Current methods of quantifying receptors on cells are either laborious or do not maintain the cells in their native form. Here, a method integrating highly sensitive bioluminescence, high precision microfluidics and small footprint of lensfree optics is developed to quantify cell surface receptors. This method is safe to use, less laborious, and faster than the conventional radiolabelling and near field scanning methods. It is also more sensitive than fluorescence based assays and is ideal for high throughput screening. In quantifying β₁ adrenergic receptors expressed on the surface of H9c2 cardiomyocytes, this method yields receptor numbers from 3.12 × 10⁵ to 9.36 × 10⁵ receptors/cell which are comparable with current methods. This can serve as a very good platform for rapid quantification of receptor numbers in ligand/drug binding and receptor characterization studies, which is an important part of pharmaceutical and biological research.     

Performance enhancement in organic photovoltaic devices using plasma-polymerized fluorocarbon-modified Ag nanoparticles

In this work, Ag nanoparticles were modified by an ultra-thin plasma-polymerized fluorocarbon film (CF_X) to form a composite CF_X-modified Ag nanoparticles/indium tin oxide (ITO) anode for application in organic photovoltaic (OPV) devices. A CF_X-modified Ag nanoparticles/ITO anode exhibited a superior surface work function of 5.4 eV suited for application in OPV devices. The performance of zinc phthalocyanine:fullerene-based OPV devices showed a significant improvement when the structural identical cells are made with the CF_X-modified Ag nanoparticles/ITO. This work yielded a promising power conversion efficiency of 3.5 ± 0.1%, notably higher than that with a bare ITO anode (2.7 ± 0.1%).