Numerical modelling of airflow dynamics and particle deposition in human lungs

Research into airflow dynamics and particle transport in human lungs is receiving considerable attention from many researchers because of its significance for human health. Drug delivery through inhalation of air into the human lung is important to prevent/cure respiratory diseases. Many researchers have investigated the process of particle transport and deposition (TD) in the respiratory airway through analytical as well as numerical methods, during the last century. Nowadays, numerical methods are used to model various biomechanical engineering problems, including particle flow in the respiratory system. The greatest challenge in numerical modelling of particle TD is the complexity of human lungs. This thesis mainly focuses on developing numerical models and investigating the effectiveness of aerosol particle inhalation as drug delivery. Particle inhalation and deposition in human lungs is affected by the lung anatomy, breathing pattern and particle properties (Rissler et al. 2017). Therefore, airflow dynamics and inhaled aerosol particle transport in the lung airways are significant for human health; thus it is important to measure both the efficiency of inhaled drug therapy and the health implications of air pollution (Deng et al. 2018). Further, the lung airways become larger as people grow into adults, and the shape of the airway structure and breathing habits change. Therefore, aging is an important factor in respiratory health. Hence, a comprehensive age-specified particle TD study is necessary to better predict drug delivery to the targeted position in a human lung. This study aims to develop an advanced and efficient three-dimensional (3D) numerical model to analyse airflow characteristics and aerosol particle TD in human lungs. The model is used to analyse the contribution of fundamental impaction and diffusion mechanisms for nanoand microscale particle TD in age-specific terminal bronchiole airways. The outcomes of this study will help improve the effectiveness of delivery of drug aerosols into human lungs to treat obstructive lung diseases including asthma, lung cancer and COPD. In addition, the inhalation of different types of pollutant particles into human lungs is investigated further to understand the consequence of the pollution particle on lung health

Novel immunologic cellular mechanisms in atherosclerosis and potential therapeutic implications

Atherosclerosis, an arterial ailment, is a major cause of cardiovascular diseases (CVD), which cause more than 17 million deaths each year and the number is expected to rise. In recent years atherosclerosis has been shown to be an inflammatory condition involving activated immunocompetent cells, including T-cells, macrophages and dendritic cells (DC), but the mechanism by which these cells are activated remains to be elucidated in detail. Treatment of atherosclerosis is still not satisfactory, primarily due to the complex underlying mechanisms, especially with respect to inflammation and immunity. An additional characteristic of atherosclerosis is the accumulation of dead cells in a necrotic core in the plaques, as well as of oxidized forms of low density lipoprotein (Ox-LDL). Interestingly, the prevalence of atherosclerotic plaques and CVD are elevated among individuals with systemic inflammatory diseases, such as systemic lupus erythematosus (SLE). These studies focused on the responses of major immunocompetent cells, such as T-cells, DC and macrophages to potential antigens, including heat shock protein (HSP) 60 and 90, phosphorylcholine (PC) and malondialdehyde (MDA), of which the latter two are components of Ox-LDL. Such investigations are related to potential links between the prototypical autoimmune disease SLE and CVD, as well as the development of novel therapies against atherosclerosis. For these purposes, we examined peripheral blood cells from healthy donors and patients with SLE, as well as cells obtained from human atherosclerotic plaques in connection with operations for CVD. We also studied a well-characterized cohort of SLE-patients, SLEVIC. Overall, we found that antibodies against phosphorylcholine (PC) and MDA were correlated with a lower prevalence of atherosclerosis among patients with SLE. Potential mechanisms involve enhanced uptake of apoptotic cells and a reduction in oxidative stress. Furthermore, anti-PC antibodies promoted polarization of T-reg cells, which may protect against both SLE and atherosclerosis. Surprisingly, production of these antibodies was dependent on T-cells. HSP60 and HSP90 exerted pro-inflammatory effects on DCs and DCs stimulated in this manner induced pro-inflammatory activation of T-cells obtained from human peripheral blood and atherosclerotic plaques. Expression of HSP60 was induced by OxLDL. A conjugate of MDA with human serum albumin (MDA-HSA) promoted pro-inflammatory activation of DCs and, subsequently, of T-cells obtained from human peripheral blood and atherosclerotic plaques via these DCs. Importantly, MDA-HSA also activated such T-cells directly. Both MDA-HSA itself and T-cells exposed to MDA-HSA promoted polarization of pro-inflammatory M1 macrophages. Annexin A5 inhibited the pro-inflammatory effects of HSP60 (in line with our previous identification of this substance as potentially protective against atherosclerosis) and anti-MDA antibodies or an inhibitor of mitochondrial production of reactive oxygen species (ROS) attenuated the activation of T-cells by MDA-HSA. Taken together, immunity plays an important role in connection with atherosclerosis and atherosclerotic plaques. Potential links between autoimmunity and atherosclerosis were identified. In particular, HSP60 and MDA may be important activators of immune cells in connection with atherosclerosis and, importantly, antibodies against PC and MDA, Annexin A5 and inhibitors of ROS could prove to be of value for prevention of and/or therapy against atherosclerosis

Development, Research and Validation of Environmental Speciation Methods; and Evaluation by Speciated Isotope Dilution Mass Spectrometry in Mercury and Chromium Speciation Analysis

The toxicity of an element depends upon its chemical forms, which also gives vital information for samples and their relevance. A sequential extraction method for mercury speciation in soil and sediments was established based on the mobility and toxicity of different mercury species and was proposed as a draft US EPA Method 3200. In order to finalize the method, an interlaboratory validation study was performed, and the final results verified the applicability of the method. Some of the widely used mercury speciation methods were evaluated during this study and the results were compared with those obtained from EPA draft Method 3200. The performances of these methods were also tested by using SIDMS technique (EPA Method 6800) as a diagnostic tool. A highly pure isotopically labeled methylmercury (CH3201Hg+) was synthesized from commercially available isotopically enriched inorganic mercury (201HgO) and tetramethyltin with a yield of more than 90% in a synthesis procedure lasting less than 1.5 h at 60 °C; the product was characterized using ICP-MS during this study. A simple and fast closed-vessel microwave-assisted extraction method based on acidic extractant has been developed for mercury speciation from soils and sediments. The optimized sample preparation was achieved in a closed-vessel system by heating 1.0 g of sample in 10.0 mL of 4.0 M HNO3 for 10 min at 100 °C with magnetic stirring. During this study, not only the SIDMS technique was established and validated for the first time for mercury speciation analysis but also a set of generic equations for one, two and three species systems in terms of unidirectional and bidirectional transformations have been developed. The modified SIDMS technique was used for the speciation of chromium from road construction materials, soils and sediments by applying microwave-assisted alkaline extraction instead of hot-plate extraction, and was observed that these matrices contain 30-70 times more Cr(VI) compared to the US EPA threshold limit (5 mg/L). This dissertation investigated and provides solution to some difficulties associated with the analyses of mercury and chromium species. The techniques developed and tested here are being adopted worldwide to assist with species related problems

Risk perception and coping strategy taken by flood victims in Kuching division, Sarawak, Malaysia

Background: Nine per cent of the total areas of Malaysia is subjected to flood. The individual’s risk perception is one of the fundamental values in determining the subsequent behaviour, action, coping mechanism and effective strategy towards possible risk. Thus, this study aims to determine the risk perception and coping strategy among the flood victims in Kuching, Sarawak, and its factors.Methods: The 200 respondents were systematically selected from three districts in Kuching division, Sarawak. Data were collected through face-to-face interviews using interviewer-administered questionnaire.Results: The analysis revealed that about three-fifths (72.5%) of the respondents were inundated last year. The most definite perceptions of risk by the flood victims were a physical health risk, followed by the capacity to mitigate flood and the perception of the social consequences. The respondents had a moderate (score of 4 to 6) to good (score of 7 to 9) level of coping strategy, which was influenced by ethnicity and level of education (p<0.05).Conclusions: Though the flood risk perception was good, it needs to go hand-in-hand with the coping measures to minimise flood impact. The planning for flood-related health programs and activities should be more community-centred by assigning villagers and the vulnerable group as committee members.

English Language Competency and Outsourced Call Centers in Bangladesh

This paper attempts to investigate whether or not the English competency of Customer Service Representatives (CSRs) is hindering the growth and development of outsourced call centers in Bangladesh. It also looks into the problems being faced by call centers in hiring English competent CSRs. A limited appraisal of the English communication training of the CSRs offered by Call Centre Training Institutes is also within the purview of the paper. With this purpose 33 supervisors of different call centers, who are in charge of monitoring the CSRs, have been interviewed with a questionnaire comprised of both close and open ended questions. The result shows there is scarcity of skilled English communicators which is one of the major barriers in the growth and development of the call centers. However, factors like product knowledge, intercultural communication skills, service personality are also crucial as they are integral for successful transaction and addressing them will pave the way for the progress of the industry. The result also implicitly indicates that mainstream education system in Bangladesh is still unable to produce competent English communicators. The findings of the study reveal that the current shortage of skilled manpower can further become more acute when call center industry grows in line with the expectation of the government. It is also revealed that the call center training institutes are incapable of delivering the kind of training required for the aspirant CSRs. This study pinpoints the necessity of future research in several directions to ensure a balance between the demand and supply of native like fluent English communicators for call center Industry in Bangladesh

The Mayer Hashi Large-Scale Program to Increase Use of Long-Acting Reversible Contraceptives and Permanent Methods in Bangladesh: Explaining the Disappointing Results. An Outcome and Process Evaluation

Background: Bangladesh has achieved a low total fertility rate of 2.3. Two-thirds of currently married women of reproductive age (CMWRA) want to limit fertility, and many women achieve their desired fertility before age 30. The incidence of unintended pregnancy and pregnancy termination is high, however. Long-acting reversible contraceptives (LARCs), consisting of the intrauterine device and implant, and permanent methods (PM), including female sterilization and vasectomy, offer several advantages in this situation, but only 8% of CMWRA or 13% of method users use these methods. Program: The Mayer Hashi (MH) program (2009–2013) aimed to improve access to and the quality of LARC/PM services in 21 of the 64 districts in Bangladesh. It was grounded in the SEED (supply–enabling environment–demand) Programming Model. Supply improvements addressed provider knowledge and skills, system strengthening, and logistics. Creating an enabling environment involved holding workshops with local and community leaders, including religious leaders, to encourage them to help promote demand for LARCs and PMs and overcome cultural barriers. Demand promotion encompassed training of providers in counseling, distribution of behavior change communication materials in the community and in facilities, and community mobilization. Methods: We selected 6 MH program districts and 3 nonprogram districts to evaluate the program. We used a before– after and intervention–comparison design to measure the changes in key contraceptive behavior outcomes, and we used a difference-in-differences (DID) specification with comparison to the nonprogram districts to capture the impact of the program. In addition to the outcome evaluation, we considered intermediate indicators that measured the processes through which the interventions were expected to affect the use of LARCs and PMs. Results: The use of LARCs/PMs among CMWRA increased between 2010 and 2013 in both program (from 5.3% to 7.5%) and nonprogram (from 5.0% to 8.9%) districts, but the rate of change was higher in the nonprogram districts. Client–provider interaction and exposure to LARCs/PMs were lower in the program than nonprogram districts, and the MH program districts had higher vacancies of key providers than the nonprogram areas, both indications of a more difficult health system environment. Conclusion: The weaknesses in the health system in the MH districts apparently undermined the effectiveness of the program. More attention to system weaknesses, such as additional supportive supervision for providers, might have improved the outcome

The Impact of Cluster Farming Approach in Simplification of Shrimp (Penaeus monodon) Marketing Channel of Paikgachha Upazila

A research study has been undertaken on shrimp marketing channel of Paikgachha upazila and its simplification process by cluster farming approach of WorldFish Center. The objectives of the study were to investigate the stakeholders involved in both existing shrimp marketing and simplified marketing channel and also determine the efficacy of cluster farming on good price and better raw materials quality. Study area possessed a complex marketing channel having at least eight stakeholders from production to processor namely, shrimp farmer; foria; local depots; large depots; aratdar, paikar; sub-agent; commission agents and exporter/processor thus flow of shrimps from gher to processors take about 20-30 hours that ultimately deteriorates the shrimp quality. This beset has been solved rather simplified through managing local depot works as partner NGO (PNGO) of WorldFish Center. The findings of the study revealed that the cluster farming approach simplified the marketing channel considerably than before. The farmers in the clusters received better price from their harvested shrimp without involvement of middlemen which resulted high quality of raw-materials with better price. Keywords: WorldFish Center, PNGO, cluster farming, foria, aratdar, paika