5,797 research outputs found

    A chromatic transient visual evoked potential based encoding/decoding approach for brain-computer interface

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    This paper presents a new encoding/decoding approach to brain-computer interface (BCI) based on chromatic transient visual evoked potential (CTVEP). The proposed CTVEP-based encoding/decoding approach is designed to provide a safer and more comfortable stimulation method than the conventional VEP-based stimulation methods for BCI without loss of efficiency. For this purpose, low-frequency isoluminant chromatic stimuli are time-encoded to serve as different input commands for BCI control, and the superior comfortableness of the proposed stimulation method is validated by a survey. A combination of diversified signal processing techniques are further employed to decode the information from CTVEP. Based on experimental results, a properly designed configuration of the CTVEP-based stimulation method and a tailored signal processing framework are developed. It is demonstrated that high performance (at information transfer rate: 58.0 bits/min, accuracy: 94.9%, false alarm rate: 1.3%) for BCI can be achieved by means of the CTVEP-based encoding/decoding approach. It turns out that to achieve such good performance, only simple signal processing algorithms with very low computational complexity are required, which makes the method suitable for the development of a practical BCI system. A preliminary prototype of such a system has been implemented with demonstrated applicability. © 2011 IEEE.published_or_final_versio

    Early Bilateral Amniotic Membrane Transplantation in the Management of Severe Ocular Involvement from Acute Toxic Epidermal Necrolysis in a Chinese Pediatric Patient

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    Introduction: Toxic Epidermal Necrolysis (TEN) is a rare but potentially life-threatening muco-cutaneous condition associated with idiosyncratic hypersensitivity to certain drugs. Ophthalmic involvement is common, typically affecting the ocular surface and eyelids. Survivors often suffer from resulting bilateral blindness and ocular dryness or pain. Objective: To report the successful management of severe ocular surface disease during the acute stage of toxic epidermal necrolysis using early amniotic membrane transplantation on both eyes in a Chinese paediatric patient. Design: Interventional case report Case Report: A 15 year-old Chinese girl was transferred to the intensive care unit of Queen Mary Hospital, Hong Kong with TEN after taking oral cefuroxime and diclofenac. She developed bilateral keratoconjunctivitis, diffuse corneal epithelial defects (80-90% of cornea surface) and later bilateral symblephara. After initial treatment with daily rodding, topical lubricants, steroids and antibiotics, there was no improvement in her condition. Bilateral amniotic membrane transplantation (AMT) was performed over the cornea, fornix, tarsal and bulbar conjunctiva on day 10 of illness. On discharge from the hospital (post-operative week 7), the patient had pinhole visual acuity of 6/7.5 in the right eye and 6/6 the left eye. She was eventually weaned off all topical medication. Visual acuity eventually recovered to 6/6 in both eyes by week 20 after surgery. There was mild residual forniceal symblepharon and eyelid margin keratinization. She continues to require regular lubricants for her chronic ocular surface condition.published_or_final_versio

    Roles of N-linked glycosylation and glycan-binding proteins in placentation: trophoblast infiltration, immunomodulation, angiogenesis, and pathophysiology

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    Protein N-linked glycosylation is a structurally diverse post-translational modification that stores biological information in a larger order of magnitude than other post-translational modifications such as phosphorylation, ubiquitination and acetylation. This gives N-glycosylated proteins a diverse range of properties and allows glyco-codes (glycan-related information) to be deciphered by glycan-binding proteins (GBPs). The intervillous space of the placenta is richly populated with membrane-bound and secreted glycoproteins. Evidence exists to suggest that altering the structural nature of their N-glycans can impact several trophoblast functions, which include those related to interactions with decidual cells. This review summarizes trophoblast-related activities influenced by N-glycan-GBP recognition, exploring how different subtypes of trophoblasts actively adapt to characteristics of the decidualized endometrium through cell-specific expression of N-glycosylated proteins, and how these cells receive decidua-derived signals via N-glycan-GBP interactions. We highlight work on how changes in N-glycosylation relates to the success of trophoblast infiltration, interactions of immunomodulators, and uterine angiogenesis. We also discuss studies that suggest aberrant N-glycosylation of trophoblasts may contribute to the pathogenesis of pregnancy complications (e.g. pre-eclampsia, early spontaneous miscarriages and hydatidiform mole). We propose that a more in-depth understanding of how N-glycosylation shapes trophoblast phenotype during early pregnancy has the potential to improve our approach to predicting, diagnosing and alleviating poor maternal/fetal outcomes associated with placental dysfunction
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