[show abstract][hide abstract] ABSTRACT: We study properties of the line at 3.33 eV observed in photoluminescence (PL) emission spectra of various ZnO films prepared using pulsed laser deposition method. The influence of deposition parameters, such as oxygen pressure, laser fluence, post-annealing, and electric field exposure on intensity of this luminescence band has been investigated. The recombination characteristics are probed by temperature and excitation dependent PL spectroscopy. The obtained experimental data suggest that the 3.33 eV luminescence line in ZnO depends strongly on surface band bending and originates from recombination of bound excitons (BEs) complex located near the surface and grain boundaries. The anomalously small thermal activation energy of BE in comparison with the localization energy is explained by decreasing of the interface barrier. Possible nature of defects that bind free excitons and cause the 3.33 eV emission line in ZnO is proposed.
Journal of Applied Physics 07/2012; 112(1). · 2.21 Impact Factor
[show abstract][hide abstract] ABSTRACT: Systemic inflammation has been suggested to be involved in the pathogenesis of chronic obstructive pulmonary disease (COPD) and metabolic syndrome. However, the association between these two conditions is not fully understood.
To evaluate the relationship between COPD and metabolic syndrome.
Among subjects aged ≥40 years from the 2001 Korean National Health and Nutrition Examination Survey, 1215 subjects with two or more acceptable spirometry measurements and complete anthropometric/laboratory examinations were analysed.
A total of 133 subjects (11%, 100 men and 33 women) were newly diagnosed with COPD (forced expiratory volume in 1 second/forced vital capacity ≤ 70%). The prevalence of metabolic syndrome, based on the National Cholesterol Education Program Adult Treatment Panel III, was significantly higher in COPD subjects compared with non-COPD subjects in both sexes (33.0% vs. 22.2% in men and 48.5% vs. 29.6% in women). In men, the risk of COPD was higher in subjects with metabolic syndrome than in those without (OR 2.03, 95%CI 1.08-3.80), after adjusting for potential confounders. There was a borderline significant association between COPD and abdominal obesity among the individual component of metabolic syndrome (OR 1.95, 95%CI 0.93-4.11).
In the Republic of Korea, metabolic syndrome was associated with COPD in men.
The international journal of tuberculosis and lung disease: the official journal of the International Union against Tuberculosis and Lung Disease 03/2012; 16(5):694-700. · 2.61 Impact Factor
[show abstract][hide abstract] ABSTRACT: The numbers of nationwide epidemiological surveys about chronic obstructive pulmonary disease (COPD) prevalence and prospective cohort studies for health care utilisation are limited. We investigated COPD-related health care utilisation in adults with obstructive lung disease in the second Korean National Health and Nutritional Survey (KNHANES II) in 2001 using Korean national medical insurance claim data.
Among people aged >40 years, obstructive lung disease (OLD) is defined according to Global Initiative for Chronic Obstructive Lung Disease criteria. Data from a total of 1942 subjects were linked with Korean national medical insurance claims data, and we investigated their COPD-related out-patient visits from 2002 to 2005.
Among the 1942 subjects, 256 (13.2%) had airflow obstruction. COPD-related out-patient visits were reported for 8.2% of patients without airway obstruction, 18.1% of those with mild airway obstruction, and 33.9% of those with moderate to very severe airway obstruction. Multivariate analysis revealed that previous COPD diagnosis by a physician (OR 2.54; P = 0.02) and lower socio-economic status (OR 0.45; P = 0.02) were independent predictors of COPD-related out-patient visits in subjects with OLD.
Of the subjects with airway obstruction, those with poor financial status utilised COPD-related health care services less frequently, and those previously diagnosed as having COPD by a physician utilised the services more frequently.
The international journal of tuberculosis and lung disease: the official journal of the International Union against Tuberculosis and Lung Disease 06/2011; 15(6):824-9. · 2.61 Impact Factor
[show abstract][hide abstract] ABSTRACT: To describe disease management, health behaviour, psychological health and quality of life (QOL) in people with chronic respiratory disease (CRD).
We analysed data from 798 adults with CRD drawn from the Korean National Health and Nutrition Examination Survey (KNHANES) 2005: 514 subjects with asthma alone, 258 with chronic obstructive pulmonary disease (COPD) alone, and 56 with asthma and COPD.
Disease management and health behaviour in this cohort were poor. One third of the cohort was not seeking any medical treatment, although many were currently experiencing respiratory symptoms. Twenty-six per cent of the subjects were current smokers who averaged 0.8 packs/day. More than half of the subjects did not exercise, only half of the subjects had regular health examinations and one third of the subjects did not get enough sleep. The study population exhibited poor psychological indices, functional health status and QOL. The combined asthma and COPD group was characterised by an increased frequency of problems related to functional status and QOL.
People with CRD are at high risk for functional limitations, unhealthy behaviour, poor mental status and poor QOL. A comprehensive disease management programme for people with CRD should be developed using collaborative team efforts.
The international journal of tuberculosis and lung disease: the official journal of the International Union against Tuberculosis and Lung Disease 06/2010; 14(6):772-8. · 2.61 Impact Factor