In-situ 3D Micro-sensor Model using Embedded Plasmonic Island for Biosensors

The design of the microsensor system for biosensors using the plasmonic island is proposed. The sensor head is formed by the stacked layers of silicon-graphene-gold materials. The dual-mode operations of the sensor can be performed using the relationship of the changes between the electron mobility and optical phase, where the exciting environment can be light intensity (phase), electrical transient, heat, pressure, flavour and smoke, The change in light phase (intensity) in silicon and conductivity (mobility) in gold layers cause change in the output measurands. The design and simulation interpretation of the sensor is presented. The sensor manipulation using the MCM arrangement is simulated and interpreted for biosensor applications 3D imaging can also be applied to the MCM function, where the 3D in situ sensor function is possible. The sensor sensitivity of 2.0 × 10−21 cm2 V−1 s−1 (mW)−1 via simulation is obtained

Plasmonic Op-Amp Circuit Model using the Inline Successive Microring Pumping Technique

The electro-optic power pumping system model using the inline successive technique within the modified add-drop filter is proposed. A pumping system consists of a closed loop panda ring resonator, from which the optical power is coupled inline into the system. By controlling the two side phase modulators, the whispering gallery mode (WGM) is generated by the amplitude-squeezed light within the modified add-drop filter. By using the proposed circuits, the low current can be applied into the system via a gold layer connection, from which the amplified output current can be obtained at the throughput port, which can be functioned as the electronic operational amplifier (Op-amp). In application, the WGM output is the amplified signal that can be used for the up (down) link in free space communication network called light fidelity (LiFi). The electro-optic signals conversion can be performed by the stacked layers of silicon-graphene-gold materials. The results obtained have shown that large gain is obtained at the WGM output, which is ~5×10-6cm².(V.sW)-1, when the pumping saturation time is ~2 fs. It concludes the suitability of our proposed model for light fidelity, LiFi up-down link conversion

Impact of direct substitution of arm span length for current standing height in elderly COPD

Chaicharn Pothirat, Warawut Chaiwong, Nittaya Phetsuk Division of Pulmonary, Critical Care and Allergy, Department of Internal Medicine, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand Background: Arm span length is related to standing height and has been studied as a substitute for current standing height for predicting lung function parameters. However, it has never been studied in elderly COPD patients. Purpose: To evaluate the accuracy of substituting arm span length for current standing height in the evaluation of pulmonary function parameters and severity classification in elderly Thai COPD patients. Materials and methods: Current standing height and arm span length were measured in COPD patients aged >60 years. Postbronchodilator spirometric parameters, forced vital capacity (FVC), forced expiratory volume in first second (FEV1), and ratio of FEV1/FVC (FEV1%), were used to classify disease severity according to global initiative for chronic obstructive lung disease criteria. Predicted values for each parameter were also calculated separately utilizing current standing height or arm span length measurements. Student’s t-tests and chi-squared tests were used to compare differences between the groups. Statistical significance was set at P<0.05. Results: A total of 106 COPD patients with a mean age of 72.1±7.8 years, mean body mass index of 20.6±3.8 kg/m2, and mean standing height of 156.4±8.3 cm were enrolled. The mean arm span length exceeded mean standing height by 7.7±4.6 cm (164.0±9.0 vs 156.4±8.3 cm, P<0.001), at a ratio of 1.05±0.03. Percentages of both predicted FVC and FEV1 values based on arm span length were significantly lower than those using current standing height (76.6±25.4 vs 61.6±16.8, P<0.001 and 50.8±25.4 vs 41.1±15.3, P<0.001). Disease severity increased in 39.6% (42/106) of subjects using arm span length over current standing height for predicted lung function. Conclusion: Direct substitution of arm span length for current standing height in elderly Thai COPD patients should not be recommended in cases where arm span length exceeds standing height by more than 4 cm. Keywords: chronic obstructive pulmonary disease, arm span, standing height, spirometry, severity&nbsp

Misidentification of airflow obstruction: prevalence and clinical significance in an epidemiological study

Chaicharn Pothirat, Warawut Chaiwong, Nittaya Phetsuk, Chalerm Liwsrisakun Division of Pulmonary, Critical Care and Allergy, Department of Internal Medicine, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand Background: The fixed threshold criterion for the ratio of forced expiratory volume in the first second to forced vital capacity (FEV1/FVC) <0.7 is widely applied for diagnosis of airflow obstruction (AO). However, this fixed threshold criterion may misidentify AO, because thresholds below the fifth percentile of normal FEV1/FVC (lower limit of normal; LLN) vary with age. This study aims to identify the prevalence of AO misidentification and its clinical significance.Materials and methods: A cross-sectional population-based study was conducted to identify the prevalence of chronic respiratory diseases in adults older than 40 years of age who live in municipal areas of Chiang Mai province, Thailand. All randomly selected subjects underwent face-to-face interviews and examinations by pulmonologists, and received chest radiographs and post-bronchodilator spirometry. AO misidentification was classified into under- or overestimated AO subgroups. Underestimated AO was defined as ratio of FEV1/FVC greater than the fixed threshold, but below the LLN criteria. Overestimated AO was defined as the ratio of FEV1/FVC below the fixed threshold but greater than the LLN criteria. The clinical significance of each misidentified subject was then explored.Results: There were 554 subjects with a mean age of 52.9±10.1 years and a percent predicted FEV1 of 85.5%±15.4%. The prevalence of AO misidentification was 5.6% (31/554), and all subjects belonged to the underestimated subgroup. Clinical significance of underestimated subjects included clinical AO disease of 22.6% (7/31) (three subjects with chronic obstructive pulmonary disease [COPD] and four subjects with asthma); chronic respiratory symptoms of 54.8% (17/31) (mostly associated with chronic rhinitis, 70.6% [12/17]); and only 12.9% (4/31) were identified as non-ill subjects.Conclusion: The prevalence of AO misidentification in this population was significant, and all were underestimated subjects. Most underestimated subjects had clinical significance as related to obstructive airway diseases and chronic respiratory symptoms, mostly associated with rhinitis. Keywords: spirometry, airflow obstruction, chronic obstructive pulmonary disease, asthm

Evaluating inhaler use technique in COPD patients

Chaicharn Pothirat, Warawut Chaiwong, Nittaya Phetsuk, Sangnual Pisalthanapuna, Nonglak Chetsadaphan, Woranoot Choomuang Division of Pulmonary, Critical Care and Allergy, Department of Internal Medicine, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand Background: Poor inhalation techniques are associated with decreased medication delivery and poor disease control in chronic obstructive pulmonary disease (COPD). The purpose of this study was to evaluate techniques for using inhaler devices in COPD patients.Methods: A prospective cross-sectional study was conducted to assess patient compliance with correct techniques for using inhaler devices across four regimens, ie, the pressurized metered-dose inhaler (pMDI), the pMDI with a spacer, the Accuhaler®, and the Handihaler®. The percentage of compliance with essential steps of correct device usage for each regimen was recorded without prior notification when COPD patients presented for a routine visit, and 1 month after receiving face-to-face training. We compared the percentage of compliance between the devices and risk factors related to incorrect techniques using logistic regression analysis. Percentage of patient compliance with correct techniques was compared between the two visits using the chi-square test. Statistical significance was set at P<0.05.Results: A total of 103 COPD patients (mean age 71.2±9.2 years, males 64.1%, low education level 82.5%, and percent predicted forced expiratory volume in 1 second 51.9±22.5) were evaluated. Seventy-seven patients (74.8%) performed at least one step incorrectly. Patients using the Handihaler had the lowest compliance failure (42.5%), and the odds ratio for failure with the other devices compared with the Handihaler were 4.6 (95% confidence interval [CI] 1.8–11.8) for the pMDI, 3.1 (95% CI 1.2–8.2) for the pMDI with a spacer, and 2.4 (95% CI 1.1–5.2) for the Accuhaler. Low education level was the single most important factor related to incorrect technique (adjusted odds ratio 4.1, 95% CI 1.2–13.4, P=0.022). Formal training resulted in a statistically significant decrease in percentage of incorrect techniques for all devices and for the pMDI (59.4% vs 48.6%, P<0.001; 72.4% vs 48.3%, P=0.039, respectively).Conclusion: Inhalation technique in COPD patients without face-to-face training was mostly unsatisfactory, especially in patients with low education levels. The Handihaler was the inhaler device associated with the lowest technique failure. Face-to-face inhalation technique training significantly increased technique compliance for the pMDI. Keywords: chronic obstructive pulmonary disease, inhalation, technique, complianc

Major affective disorders in chronic obstructive pulmonary disease compared with other chronic respiratory diseases

Chaicharn Pothirat, Warawut Chaiwong, Nittaya Phetsuk, Sangnual Pisalthanapuna, Nonglak Chetsadaphan, Juthamas InchaiDivision of Pulmonary, Critical Care and Allergy, Department of Internal Medicine, Faculty of Medicine, Chiang Mai University, Chiang Mai, ThailanBackground: Chronic obstructive pulmonary disease (COPD) and other chronic respiratory diseases (CRDs) have significant impacts on quality of life including psychomotor domain.Purpose: To evaluate three major affective disorders in subjects with COPD compared with other CRDs and nonill population.Materials and methods: The Thai version of Mini International Neuropsychiatric Interview (MINI) was used as a diagnostic instrument for three major affective disorders (generalized anxiety disorder, major depressive disorder, and panic disorder) by face-to-face interview in assessing patients with CRDs [COPD, asthma, rhinasthma, all asthma (asthma and rhinasthma), and chronic rhinitis], and nonill subjects. Logistic regression analyses were used to determine the relation between major affective disorders and CRDs adjusting for age, sex, and disease severity.Results: Major affective disorders were more prevalent in CRDs than nonill groups (adjusted OR =2.6 [95% CI, 1.8-3.9], P<0.001). COPD patients had significantly more generalized anxiety and panic disorder (adjusted OR =4.0 [95% CI, 1.4-11.9], P=0.011, and 4.4 [95% CI, 1.1-18.1], P=0.038, respectively) but not major depressive disorder (adjusted OR =2.7 [95% CI, 0.8-9.0, P=0.105]) than nonill group. Comparing with all asthma, COPD patients had lower occurrence of major depressive and panic disorders (adjusted OR =0.1 [95% CI, 0.0-0.4], P=0.002, and 0.1 [95% CI, 0.0-0.9], P=0.043, respectively). There was no difference in major mood disorders in COPD, rhinasthma, and chronic rhinitis patients. Major affective disorders were not increased by disease severity in COPD.Conclusion: Major affective disorders were significantly higher in CRDs than nonill population. Generalized anxiety and panic disorders were significantly high in COPD patients. Moreover, major depressive and panic disorders in COPD were significantly lower than all asthma. The prevalence of major affective disorders may not be related to severity of COPD.Keywords: respiration disorders, asthma, airway obstruction, rhinitis, mood disorder

A comparative study of COPD burden between urban vs rural communities in northern Thailand

Chaicharn Pothirat, Warawut Chaiwong, Nittaya Phetsuk, Sangnual Pisalthanapuna, Nonglak Chetsadaphan, Juthamas Inchai Division of Pulmonary, Critical Care and Allergy, Department of Internal Medicine, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand Background: COPD prevalence and consequent burden are expected to rapidly increase worldwide. Until now, there has been no community-based study of COPD in Thailand.Purpose: We aimed to compare the prevalence, clinical characteristics, disease severity, previous diagnosis, and management of COPD between urban and rural communities.Materials and methods: A population-based cross-sectional study was designed to compare COPD prevalence and burden in rural and urban communities in Chiang Mai Province, Thailand. The COPD subjects were diagnosed and severity categories assigned using Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria. The prevalence between the groups was compared using risk regression analysis. Unpaired t-test and chi-square were used to compare differences between the groups.Results: There were 574 and 293 enrolled subjects with acceptable spirometry, in rural and urban communities respectively. The prevalence of COPD in general and COPD in females was higher in the rural group (6.8% vs 3.7% and 4.4% vs 0.9%, respectively) across all independent variables. However, after adjustment for age, sex, and smoking status, no significant differences were demonstrated. Although the pulmonary function and disease severity between the two groups were not significantly different, the tendency was more pronounced in the rural group (COPD stage III-IV: 65.0% vs 33.3%). Most of the COPD patients in both groups were underdiagnosed (80.0% vs 77.2%) and undertreated (85.0% vs 81.9%). None of the patients in the study had participated in exercise training programs.Conclusion: The prevalence of COPD in general and particularly COPD in females tended to be higher, with more severe disease in the rural community. However, both groups were similarly underdiagnosed and undertreated. Keywords: chronic obstructive pulmonary disease, spirometry, prevalenc

Long-term efficacy of intensive cycle ergometer exercise training program for advanced COPD patients

Chaicharn Pothirat, Warawut Chaiwong, Nittaya Phetsuk, Chalerm Liwsrisakun, Chaiwat Bumroongkit, Athavudh Deesomchok, Theerakorn Theerakittikul, Atikun Limsukon Division of Pulmonary, Critical Care and Allergy, Department of Internal Medicine, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand Background: Exercise training has been incorporated into the international guidelines for the treatment of chronic obstructive pulmonary disease (COPD). However, the long-term efficacy of the training program for patients with advanced COPD has never been evaluated in Thailand. Purpose: To determine the long-term efficacy of intensive cycle ergometer exercise program on various clinical parameters of patients with advanced COPD. Materials and methods: The patients with advanced COPD were separated into two groups: the intensive ergometer exercise program group and the control group. The clinical parameters of all the patients were assessed at baseline, every month for the first 3 months, and then every 3 months until they had completed the 24-month follow-up. Mann–Whitney U test was used to compare baseline mean differences between the groups. Repeated measure analysis was applied to determine the progress in all parameters during the entire follow-up period. Mean incase imputation method was applied to estimate the parameters of dropout cases. Results: A total of 41 patients were enrolled: 27 in the intensive ergometer exercise program group and 14 in the control group. The intensive cycle ergometer exercise program group showed statistically significant improvements in muscle strength (from month 1 till the end of the study, month 24), endurance time (from month 1 till the end of measurement, month 12) and clinically significant improvements in 6-minute walk distance (from month 2 until month 9), dyspnea severity by transitional dyspnea index (from month 1 till the end of the study, month 24), and quality of life (from month 1 till the end of the study, month 24). There was no significant difference in survival rates between the groups. Conclusion: The intensive ergometer exercise training program revealed meaningful long-term improvements in various clinical parameters for up to 2 years. These promising results should encourage health care professionals to promote exercise training for patients with advanced COPD who have limited daily activities despite optimal medication control. Keywords: chronic obstructive pulmonary disease, pulmonary rehabilitation, ergometer training, physical endurance, strength trainin

Dialectal influence on chronic pulmonary disease assessment test: the reliability and validity study

Chaicharn Pothirat, Warawut Chaiwong, Nittaya Phetsuk, Chalerm Liwsrisakun, Chaiwat Bumroongkit, Athavudh Deesomchok, Theerakorn Theerakittikul, Atikun Limsukon Division of Pulmonary, Critical Care and Allergy, Department of Internal Medicine, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand Background: Chronic obstructive pulmonary disease (COPD) patients living in many countries are familiar with local dialects rather than the official language. We, therefore, compare the reliability and validity of the COPD assessment test (CAT) in Thai and northern Thai dialect versions, in stable COPD patients living in the northern part of Thailand.Methods: A total of 160 COPD patients were randomly selected for the evaluation of each dialect version of CAT (n=80). The internal consistency of all eight items and test–retest reliability were investigated by using Cronbach’s alpha coefficient and intraclass correlation coefficient (ICCC), respectively. The validity was evaluated by the degree of correlation with St George’s Respiratory Questionnaire (SGRQ) using Pearson’s correlation. The correlations of CAT with clinical parameters such as forced expiratory volume in the first second (FEV1), modified Medical Research Council scale (mMRC) dyspnea score, and 6-minute walk distance (6-MWD) were also evaluated.Results: The two versions of CAT showed high internal consistency reliability (Cronbach’s alpha coefficient of 0.82 and 0.76) as well as a high test–retest reliability (ICCC of 0.82 and 0.84) for Thai and northern Thai dialect versions, respectively. The test results revealed that the northern Thai dialect version had good correlation with SGRQ whereas the Thai version correlated only moderately.Conclusion: The two Thai versions of CAT were proven to be good clinical tools with high reliability and acceptable validity for assessing the quality of life of Thai COPD patients. However, the northern Thai dialect version is more suitable for evaluating COPD patients living in the northern part of Thailand. Keywords: chronic obstructive pulmonary disease, COPD assessment test, quality of life, validation, reliabilit