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.
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).
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)
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.