Stress and its effect on optical properties of AlN nanorods

2009-2010 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Does timing of surgery matter in fragility hip fractures?

The effect of delay of surgery on the geriatric hip fractures has been a subject of interest in the past two decades. While the elderly patients will not tolerate long periods of immobilization, it is still unclear how soon these surgeries need to be performed. A review of existing literature was performed to examine the effect of timing of surgery on the different outcome parameters of these patients. Although there is conflicting evidence that early surgery would improve mortality, there is widespread evidence in the literature that other outcomes including morbidity, the incidence of pressure sores, and the length of hospital stay could be improved by shortening the waiting time of hip fracture surgery. We concluded that it is beneficial to the elderly patients to receive surgical treatment as an urgent procedure as soon as the body meets the basic anesthetic requirements. © 2010 The Author(s).published_or_final_versionSpringer Open Choice, 21 Feb 201

Optically and electrically tunable graphene quantum dot–polyaniline composite films

Graphene quantum dot-polyaniline (PANI-GQD) composite films were synthesized by a chemical oxidation polymerization process. The optical properties of the PANI-GQD composite were studied by varying the mole concentration of PANI and the size of the GQDs. The Au/PANI-GQDs/ITO sandwich device was fabricated in order to investigate the transport properties of the composite. A stable hysteresis loop was observed in response to the applied voltage. By varying the PANI content and size of the GQDs, the area within the hysteresis loop and electrical conductance behavior of the device can be tuned in a controlled manner. Both the tunable luminescence and electrical hysteresis behavior are attributed to surface states of the GQDs. The PANI-GQD composite films are expected to find application in photonic devices.Department of Applied Physic

Awareness of form-sound correspondence in Chinese children with dyslexia: Preliminary results from event-related potentials and time frequency analyses

Developmental dyslexia has usually been characterized as having difficulties learning grapheme-phoneme correspondence and applying the mappings. This study investigates form-sound awareness in Chinese reading-impaired children in terms of regularity, consistency and lexicality effects using event-related potentials (ERP) and time-frequency analysis (TFA). Preliminary data from two Cantonese-speaking male children, one with reading impairment (PR) and one with normal reading performance (CA), performing a character recognition task were collected. ERP results indicated that CA showed a lexicality effect at N400 that was not evident in PR. TFA showed that CA exhibited greater event-related synchronization (ERS) and phase coherence at theta and gamma bands suggesting greater cognitive demand in processing pseudo and irregular characters. An opposite pattern was observed for PR, where greater effort was needed to retrieve information related to real and regular characters whilst failing to respond to pseudo and irregular characters. Greater ERS and phase coherence was also observed for real, pseudo and regular characters at 350-450ms at theta suggesting adequate access to phonological and semantic information for CA compared to PR. Whereas PR showed greater ERS and phase coherence at earlier and later time intervals. These initial findings suggest that PR may have weaker semantic representations and may be less sensitive to the internal structure of characters and its relationship with sounds. © 2011 IEEE.published_or_final_versio

An ERP study of effects of regularity and consistency in delayed naming and lexicality judgment in a logographic writing system

Phonological access is an important component in theories and models of word reading. However, phonological regularity and consistency effects are not clearly separable in alphabetic writing systems. We investigated these effects in Chinese, where the two variables are operationally distinct. In this orthographic system, regularity is defined as the congruence between the pronunciation of a complex character (or phonogram), and that of its phonetic radical, while phonological consistency indexes the proportion of orthographic neighbors that share the same pronunciation as the phonogram. In the current investigation, regularity and consistency were contrasted in an event-related potential (ERP) study using a lexical decision task and a delayed naming task with native Chinese readers. ERP results showed that effects of regularity occurred early after stimulus onset and were long-lasting. Regular characters elicited larger N170, smaller P200, and larger N400 compared to irregular characters. In contrast, significant effects of consistency were only seen at the P200 and consistent characters showed a greater P200 than inconsistent characters. Thus, both the time course and the direction of the effects indicated that regularity and consistency operated under different mechanisms and were distinct constructs. Additionally, both of these phonological effects were only found in the delayed naming task and absent in lexical decision, suggesting that phonological access was non-obligatory for lexical decision. The study demonstrated cross-language variability in how phonological information was accessed from print and how task demands could influence this process.published_or_final_versio

Spherically shaped active transducer based on proton-irradiated vinylidene fluoride-trifluoroethylene 70/30 mol% copolymer

2006-2007 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Distinctive effects of regularity and consistency in orthography-phonology mapping in a logographic writing system: an ERP study

Poster Session E - Motor Control, Speech Production, Sensorimotor Integration: no. E23In alphabetic scripts, phonological regularity and consistency of print-to-sound mapping are not clearly separable. In contrast, these variables are operationally distinct in Chinese. About 80% of Chinese characters are phonograms, containing a semantic radical that provides a clue to the meaning of the character and a phonetic radical providing a clue to the pronunciation (e.g. 趾 zi2 ‘toe’ has a semantic radical 足meaning ‘foot’ and a phonetic radical 止 zi2). The orthographyphonology mapping in Chinese can be characterized in terms of regularity defined as the congruence between the pronunciation of a phonogram and that of its phonetic radical, and ...postprin

Training negative connectivity patterns between the dorsolateral prefrontal cortex and amygdala through fMRI-based neurofeedback to target adolescent socially-avoidant behaviour

Social anxiety is prevalent in adolescence. Given its role in maintaining fears, reducing social avoidance through cognitive reappraisal may help attenuate social anxiety. We used fMRI-based neurofeedback (NF) to increase 'adaptive' patterns of negative connectivity between the dorsolateral prefrontal cortex (DLPFC) and the amygdala to change reappraisal ability, and alter social avoidance and approach behaviours in adolescents. Twenty-seven female participants aged 13-17 years with varying social anxiety levels completed a fMRI-based NF training task where they practiced cognitive reappraisal strategies, whilst receiving real-time feedback of DLPFC-amygdala connectivity. All participants completed measures of cognitive reappraisal and social approach-avoidance behaviour before and after NF training. Avoidance of happy faces was associated with greater social anxiety pre-training. Participants who were unable to acquire a more negative pattern of connectivity through NF training displayed significantly greater avoidance of happy faces at post-training compared to pre-training. These 'maladaptive' participants also reported significant decreases in re-appraisal ability from pre to post-training. In contrast, those who were able to acquire a more 'adaptive' connectivity pattern did not show these changes in social avoidance and re-appraisal. Future research could consider using strategies to improve the capacity of NF training to boost youth social-approach behaviour

Short circuit current improvement in planar heterojunction organic solar cells by multijunction charge transfer

A multijunction structure was applied on an organic photovoltaic (OPV) device for broadening the absorption spectrum and enhancing the power conversion efficiency through charge transfer process. By inserting the tris[4-(2-thienyl)]amine (TTPA) into a boron subphthalocyanine chloride (SubPc)/C 60 OPV device, the short circuit current density (J sc) showed a 47.5% increases from 3.05 to 4.50 mA/cm 2 in the bilayer planar heterojunction device, while the open circuit voltage (V oc) remained constant. Based on the single junction (TTPA/SubPc) device and photoluminescence absorption results, we confirmed both TTPA/SubPc and SubPc/C 60 junctions are contributing to the exciton dissociation process hence the efficiency enhancement. © 2012 American Institute of Physics.published_or_final_versio

Learning to read a logographic writing system as a second language: an ERP study of L2 Chinese proficient readers

Poster Session E - Language Development, Plasticity, Multilingualism: no. E33For native readers of alphabetic scripts, learning to read a logographic system such as Chinese is challenging. This is not only because Chinese characters look drastically unlike from words in alphabetic scripts, but also because mappings between orthographic and phonological units in the two systems are different. In this study, we investigated two measures of orthography-phonology mapping-- phonological regularity and consistency--in relatively proficient late-acquired second language (L2) readers of Chinese in lexical decision (LD) and delayed naming (DN) tasks. Most Chinese characters are phonograms, which have a phonetic radical that carries phonological ...postprin