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  1. Leung R, Ho P, Lam CW, Lai CK
    J. Allergy Clin. Immunol., 1997 May;99(5):594-9.
    PMID: 9155823
    BACKGROUND: Allergen sensitization is associated with asthma and allergic disease in children, but such a relationship has not been confirmed in Chinese populations.

    OBJECTIVES: The objective of this study was to evaluate the effects of allergen sensitization and family history of atopy on asthma and allergic disease in Chinese schoolchildren from three southeast Asian populations.

    METHODS: Written questionnaires on respiratory and allergic symptoms were completed by parents of children of secondary-school age (age range 12 to 18 years) in Hong Kong (n = 1062), Kota Kinabalu in eastern Malaysia (n = 409), and San Bu in southern China (n = 737). A subsample of school-children underwent skin prick testing to common inhalant allergens (Hong Kong 471 children, Kota Kinabalu 321, San Bu 647).

    RESULTS: The prevalence of asthma and allergic disease in schoolchildren was highest in Hong Kong, intermediate in Kota Kinabalu, and lowest in San Bu. However, the overall rate of atopic sensitization was similar in the three populations (49% to 63%). House dust mite and cockroach were the two most common allergens causing sensitization and these gave rise to more than 95% of the positive skin test results in all three populations. By regression analysis, mite allergy was associated with rhinitis and asthma in all three populations, and a family history of asthma, rhinitis, or eczema was strongly associated with respective symptoms in the subjects. After adjusting for age, sex, atopic status, and family history of allergic disease, the place of residence remained a significant independent factor for asthma (odds ratio [OR] = 1.0 for Hong Kong, 0.57 for Kota Kinabalu, 0.15 for San Bu, p < 0.001), rhinitis (OR = 1.0 for Hong Kong, 0.59 for Kota Kinabalu, 0.15 for San Bu, p < 0.001), or eczema (OR = 1.0 for Hong Kong, 0.35 for Kota Kinabalu, 1.01 for San Bu, p < 0.001).

    CONCLUSION: Sensitization to indoor allergens was a significant risk factor for asthma and allergic disease, and familial clustering of disease was common in the region. However, the marked difference in disease prevalence in the three southeast Asian populations of Chinese schoolchildren cannot be explained by atopic sensitization and family history alone, and the place of residence was an independent risk factor for asthma and allergies, which suggests an important environmental role in disease pathogenesis.

  2. Ghadiry M, Gholami M, Lai CK, Ahmad H, Chong WY
    PLoS ONE, 2016;11(4):e0153949.
    PMID: 27101247 DOI: 10.1371/journal.pone.0153949
    Generally, in a waveguide-based humidity sensors, increasing the relative humidity (RH) causes the cladding refractive index (RI) to increase due to cladding water absorption. However, if graphene oxide (GO) is used, a reverse phenomenon is seen due to a gap increase in graphene layers. In this paper, this interesting property is applied in order to fabricate differential humidity sensor using the difference between RI of reduced GO (rGO) and nano-anatase TiO2 in a chip. First, a new approach is proposed to prepare high quality nano-anatase TiO2 in solution form making the fabrication process simple and straightforward. Then, the resulted solutions (TiO2 and GO) are effortlessly drop casted and reduced on SU8 two channels waveguide and extensively examined against several humid conditions. Investigating the sensitivity and performance (response time) of the device, reveals a great linearity in a wide range of RH (35% to 98%) and a variation of more than 30 dB in transmitted optical power with a response time of only ~0.7 sec. The effect of coating concentration and UV treatment are studied on the performance and repeatability of the sensor and the attributed mechanisms explained. In addition, we report that using the current approach, devices with high sensitivity and very low response time of only 0.3 sec can be fabricated. Also, the proposed device was comprehensively compared with other state of the art proposed sensors in the literature and the results were promising. Since high sensitivity ~0.47dB/%RH and high dynamic performances were demonstrated, this sensor is a proper choice for biomedical applications.
  3. Chong WY, Lim WH, Yap YK, Lai CK, De La Rue RM, Ahmad H
    Sci Rep, 2016 Apr 01;6:23813.
    PMID: 27034015 DOI: 10.1038/srep23813
    Increased absorption of transverse-magnetic (TM)-polarised light by a graphene-oxide (GO) coated polymer waveguide has been observed in the presence of transverse-electric (TE)-polarised light. The GO-coated waveguide exhibits very strong photo-absorption of TE-polarised light--and acts as a TM-pass waveguide polariser. The absorbed TE-polarised light causes a significant temperature increase in the GO film and induces thermal reduction of the GO, resulting in an increase in optical-frequency conductivity and consequently increased optical propagation loss. This behaviour in a GO-coated waveguide gives the action of an inverted optical switch/modulator. By varying the incident TE-polarised light power, a maximum modulation efficiency of 72% was measured, with application of an incident optical power level of 57 mW. The GO-coated waveguide was able to respond clearly to modulated TE-polarised light with a pulse duration of as little as 100 μs. In addition, no wavelength dependence was observed in the response of either the modulation (TE-polarised light) or the signal (TM-polarised light).
  4. Zainudin BM, Lai CK, Soriano JB, Jia-Horng W, De Guia TS, Asthma Insights and Reality in Asia-Pacific (AIRIAP) Steering Committee
    Respirology, 2005 Nov;10(5):579-86.
    PMID: 16268910
    OBJECTIVE: The Asthma Insights and Reality in Asia-Pacific (AIRIAP) survey collected detailed information on asthma severity and management in the urban centres of eight areas of the Asia-Pacific region. This study compared asthma morbidity and management practices in these areas.
    METHODOLOGY: Following recruitment, face-to-face interviews were completed with 2323 adults with diagnosed asthma, who had current symptoms or were using asthma medication. Comparisons between areas were made for asthma severity, asthma burden and management practices.
    RESULTS Asthma severity varied significantly between areas (P < 0.01), with Vietnam and mainland China reporting the most cases with severe, persistent symptoms. Severity of asthma was significantly associated with advancing age and a lower level of education in a multivariate analysis (P < 0.001). The total use of acute healthcare for asthma was significantly associated with increased asthma severity. Work absence due to asthma was highest in the Philippines (46.6%) and lowest in South Korea (7.5%). The use of inhaled corticosteroids was associated with age in a non-linear manner. There was significant variation among countries in usage of inhaled corticosteroids, from 1.3% in South Korea to 29.0% in Taiwan (P < 0.00001). A peak flow meter was owned by a total of 7.7% of respondents, and overall, 17.9% of adults had a written action plan for asthma management.
    CONCLUSIONS: Within the Asia-Pacific region, asthma in adults differs significantly in disease severity, management and treatment according to area of residence. International recommendations on the management of asthma are generally not being followed.
    Study site: urban areas in several countries in Asia-Pacific region (via random street interception, random door-to-door recruitment, or telephone recruitment)
  5. Lai CK, De Guia TS, Kim YY, Kuo SH, Mukhopadhyay A, Soriano JB, et al.
    J. Allergy Clin. Immunol., 2003 Feb;111(2):263-8.
    PMID: 12589343
    Few data on asthma management are available for the Asia-Pacific region.
  6. Katelaris CH, Lai CK, Rhee CS, Lee SH, Yun WD, Lim-Varona L, et al.
    Am J Rhinol Allergy, 2011 Sep-Oct;25 Suppl 1:S3-15.
    PMID: 22185687 DOI: 10.2500/ajra.2011.25.3674
    The Allergies in Asia-Pacific Survey describes the symptoms, impact, and treatment of allergic rhinitis (AR) across Australia, China, Hong Kong, Malaysia, Singapore, Taiwan, Vietnam, and the Philippines. The Allergies in Asia-Pacific Survey was undertaken to further clarify the prevalence of physician-diagnosed nasal allergies (NAs), impact on quality-of-life (QOL), existing treatment paradigms and gaps, and NA medications currently used in treatment.
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