Analysis And Removal of Artifacts in Electroencephalographic Recordings using Microstate Analysis and Randomization Statistics

Electroencephalography (EEG) is a popular method to detect brain-neuron activities because of its high temporal resolution. However, very often, various types of biological and non-biological signals contaminate EEG recordings. These non-neural signals create EEG-artifacts, which cause unintentional control in the brain-computer interface related applications and difficulty in the analysis and interpretation of EEG-data. While these artifacts corrupt and mask the underlying neural activity in general, the contaminated EEG data due to the contraction and expansion of the scalp-muscles are called electromyogram (EMG) artifacts. In particular, the frontalis and temporalis scalp-muscles seriously affect the EEG-signals ranging from 0-200 Hz frequency band. This thesis studies the most common EMG artifacts originating from these two brain regions. Its aim is to analyze and remove the EMG artifacts using microstate analysis and randomization statistics. The thesis first presents a brief literature review of the EEG-artifacts, followed by the preprocessing and analysis of the EEG recordings using EEG signal-power analysis. The purpose of this analysis is to detect the EMG contaminated EEG data-segments or epochs due to frontalis and temporalis scalp muscles (EMG-artifacts). The preliminary step in this analysis includes the transformation of the EEG epochs into the frequency domain through discrete-Fourier transform. Then the signal-powers of the EEG epochs are calculated and compared to some threshold values. These threshold values are selected based on the mean signal-power amplitudes of the EEG-epochs of the highly contaminated EEG data channels representing the frontalis and temporalis brain regions. Electric potentials from the frontalis and temporalis region of the brain project a set of spatial patterns on the scalp surface. These spatial patterns can be clustered into a set of representative maps called microstates. Using microstate analysis, the EMG-contaminated and non-contaminated EEG epochs, obtained from signal-power analysis are clustered into an optimal number of microstates. This number best explains the data variance of both groups of EEG epochs. The difference between these microstate features can be used to distinguish artifactual and pure EEG epochs. To find the significant-differences, we have calculated the feature-differences of these microstates after a random group-wise shuffling of the EEG epochs many times to generate a distribution of the feature-differences. The research hypothesis of this distribution is that the differences in features have occurred by chance. To reject this hypothesis, we compare the probability of this distribution to the difference in features obtained before group-wise random shuffling of the EEG epochs. This technique is called multivariate randomization statistics. It has a higher statistical power compared to classical statistics to find a statistically significant difference. In this thesis, we analyze the EEG recordings of four subjects to detect the EMG artifacts by EEG signal-power analysis. We propose a method to remove EMG artifact from EEG recordings in two steps. In the first step, we cluster the EMG contaminated and non-contaminated EEG epochs obtained from signal-power analysis into ten optimal microstates and calculate three temporal features. In the second step, through randomization statistical analysis, we differentiate between the artifactual and pure EEG epochs and reconstruct the EMG-artifact free EEG data. Finally, we validate the proposed method by comparing it with independent component analysis (ICA), a signal processing technique for separating the additive sub-components of a multivariate signal. We have found that our proposed method gives similar results to that of ICA. Our research findings suggest that a combination of microstate analysis with randomization statistics be an effective-method in the removal of EMG-artifacts

A Machine Learning Based Approach to Accelerate Catalyst Discovery

Computational catalysis, in contrast to experimental catalysis, uses approximations such as density functional theory (DFT) to compute properties of reaction intermediates. But DFT calculations for a large number of surface species on variety of active site models are resource intensive. In this work, we are building a machine learning based predictive framework for adsorption energies of intermediate species, which can reduce the computational overhead significantly. Our work includes the study and development of appropriate machine learning models and effective fingerprints or descriptors to predict energies accurately for different scenarios. Furthermore, Bayesian inverse problem, that integrates experimental catalysis with its computational counterpart, uses Markov chain Monte Carlo (MCMC) methods to refine the uncertainties on the quantities-of-interest such as turnover frequency. However, large number of forward simulations required by MCMC can become a bottleneck, especially in computational catalysis, where the evaluation of likelihood functions involves finding the solution to microkinetic models. A novel and faster MCMC method is proposed to reduce the number of expensive target evaluations and to shorten the burn-in period by emulating the target along with using a better informed proposal distribution

Impacts of cyclone and flood on crop and fish production in disaster prone coastal Bhola district of Bangladesh

This study assessed the impact of climate change induced disaster on crops and fisheries production at Bhola Sadar and Monpura upazila of Bhola district, Bangladesh during January to June 2018. The study was gathered primary data from primary observation (PO), questionnaire survey (QS), focus group discussion (FGD), and key informant interview (KII). Secondary data were collected from Upazila Agricultural Office and Upazila Fisheries Office of Bhola Sadar and Manpura upazila and moreover, climatic data were collected from Bangladesh Meteorological Department. Results of the study found that trend analysis indicates overall annual maximum temperature increased for Kharif-I, Kharif-II and Rabi season. Average annual minimum temperature also increased for Kharif-I season but decreased for Kharif-II and Rabi season. Study also found that for all cropping season average relative humidity was increased. Annual average rainfall exhibited decreasing trend for Kharif-I and Rabi season but increased for Kharif-II season in (1990-2019) time period. The Aus, T. Aman, Boro and Mung bean was dominant cropping pattern in Kharif-I, Kharif- II and Rabi season in Bhola district. Overall, Aus rice production in Kharif-I season increased but in 2009, 2013 production was decreased because of cyclone Aila (2009) and Cyclone Mahasen (2013). T. Aman production hampered due to Cyclone Sidr (2007) and flood (2014) in Kharif-II season. In Rabi season Boro rice production lessen because of low rainfall and salinity intrusion. Overall, Mung bean production increase but in 2008 and 2009 production become hampered due to late cultivation because of Cyclone Sidr (2007). Fish production rate increase in Bhola specially Hilsha fish because of non-climatic factor like raid in non-fishing time, banned current net but fish production in pond become diminished due to infrequent natural disaster. Practicing of salt and flood tolerant varieties, floating bed vegetable cultivation, and mixed cropping system (mainly for Rabi season), enhanced expedition activities against catching mother Ilish in prohibition period, dredging in the heart of the river which can eventually reduce vulnerabilities and increase crop and fish production in the Bhola region. Int. J. Agril. Res. Innov. Tech. 10(1): 40-55, June 202

Pragmatism for Biomedical Laws of Bangladesh

Pragmatism is a school of moral philosophy, and of contemporary in origin, comparing to the other schools of moral philosophy. It evaluates the action based on the practical applicability and relevance. Pragmatism can, therefore, be useful to make a law that govern the society contemporary and relevant for the constantly changing world. Biomedical laws in particular are needed to correspond to the changing standards and good practices in tandem with their advancements. This paper will assess from a pragmatic point of view, the efficacy of the biomedical laws of Bangladesh

Fluorogenic properties of 4-dimethylaminocinnamaldehyde (DMACA) enable high resolution imaging of cell-wall-bound proanthocyanidins in plant root tissues

Proanthocyanidins (PAs) are polymeric phenolic compounds found in plants and used in many industrial applications. Despite strong evidence of herbivore and pathogen resistance-related properties of PAs, their in planta function is not fully understood. Determining the location and dynamics of PAs in plant tissues and cellular compartments is crucial to understand their mode of action. Such an approach requires microscopic localization with fluorescent dyes that specifically bind to PAs. Such dyes have hitherto been lacking. Here, we show that 4-dimethylaminocinnamaldehyde (DMACA) can be used as a PA-specific fluorescent dye that allows localization of PAs at high resolution in cell walls and inside cells using confocal microscopy, revealing features of previously unreported wall-bound PAs. We demonstrate several novel usages of DMACA as a fluorophore by taking advantage of its double staining compatibility with other fluorescent dyes. We illustrate the use of the dye alone and its co-localization with cell wall polymers in different Populus root tissues. The easy-to-use fluorescent staining method, together with its high photostability and compatibility with other fluorogenic dyes, makes DMACA a valuable tool for uncovering the biological function of PAs at a cellular level in plant tissues. DMACA can also be used in other plant tissues than roots, however care needs to be taken when tissues contain compounds that autofluoresce in the red spectral region which can be confounded with the PA-specific DMACA signal

Traditional family planning in Bangladesh

“Traditional” methods of family planning (FP) generally are methods such as withdrawal and periodic abstinence that do not require contraceptive substances or devices, or clinical procedures. In 1991, approximately 38 million couples worldwide relied on withdrawal to prevent pregnancy, and 30-35 million relied on periodic abstinence. Together, these constituted one-quarter of all users of temporary methods of FP worldwide. In Bangladesh, the proportion using periodic abstinence or withdrawal was more than 20 percent of users of temporary methods. The reasons for use of traditional methods have not been investigated in Bangladesh, because of overriding attention to modern methods. Given that the use of traditional methods is widespread, what is the level of knowledge among Bangladeshi users about the safe periods of the monthly cycle for the most effective use of periodic abstinence? What factors cause higher socioeconomic groups to be the main users of traditional methods? Why do some people switch between traditional and modern methods? This report investigates these questions, and others, but is aimed at determining the main policy issues and the policy implications of findings

Laccaria bicolor pectin methylesterases are involved in ectomycorrhiza development with Populus tremula x Populus tremuloides

The development of ectomycorrhizal (ECM) symbioses between soil fungi and tree roots requires modification of root cell walls. The pectin-mediated adhesion between adjacent root cells loosens to accommodate fungal hyphae in the Hartig net, facilitating nutrient exchange between partners. We investigated the role of fungal pectin modifying enzymes in Laccaria bicolor for ECM formation with Populus tremula x Populus tremuloides. We combine transcriptomics of cell-wall-related enzymes in both partners during ECM formation, immunolocalisation of pectin (Homogalacturonan, HG) epitopes in different methylesterification states, pectin methylesterase (PME) activity assays and functional analyses of transgenic L. bicolor to uncover pectin modification mechanisms and the requirement of fungal pectin methylesterases (LbPMEs) for ECM formation. Immunolocalisation identified remodelling of pectin towards de-esterified HG during ECM formation, which was accompanied by increased LbPME1 expression and PME activity. Overexpression or RNAi of the ECM-induced LbPME1 in transgenic L. bicolor lines led to reduced ECM formation. Hartig Nets formed with LbPME1 RNAi lines were shallower, whereas those formed with LbPME1 overexpressors were deeper. This suggests that LbPME1 plays a role in ECM formation potentially through HG de-esterification, which initiates loosening of adjacent root cells to facilitate Hartig net formation

Gene Modification in Non-Human Animal for Developing Human Compatible Organs: Ethical, Legal, Clinical and Societal Issues

CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) as a gene editing tool is a precise and promising technology. By CRISPR technology, human gene can be introduced into the animal gene pool to develop chimera for human like cells/tissue. However, the long term effects of gene editing in human is unknown. After revisiting the state-of-the-art publications in this discipline, it appears that the possibility of development to full-term chimeric/non-human animal by CRISPR technic for xenotransplantation is a future reality. Concern over the safety and ethical issues of gene modification remain for the xenotransplant recipient and the regulators. Countries like UK and the USA might find a leeway within which they would legally practice the research of development of the “non-human animal” to extract organs genetically compatible with the human body by hovering around the legal terminology. This article highlights the clinical, ethical, legal, and social issues of chimeric non-human animals for developing human-compatible organs. We have predicted how real and near the future is for gene modification and animal-human chimera formation for the purpose of xenotransplantation

Micronutrients and Anaemia

Micronutrient deficiencies and anaemia remain as major health concerns for children in Bangladesh. Among the micronutrient interventions, supplementation with vitamin A to children aged less than five years has been the most successful, especially after distribution of vitamin A was combined with National Immunization Days. Although salt sold in Bangladesh is intended to contain iodine, much of the salt does not contain iodine, and iodine deficiency continues to be common. Anaemia similarly is common among all population groups and has shown no sign of improvement even when iron-supplementation programmes have been attempted. It appears that many other causes contribute to anaemia in addition to iron deficiency. Zinc deficiency is a key micronutrient deficiency and is covered in a separate paper because of its importance among new child-health interventions

Accretion Processes for General Spherically Symmetric Compact Objects

We investigate the accretion process for different spherically symmetric space-time geometries for a static fluid. We analyse this procedure using the most general black hole metric ansatz. After that, we examine the accretion process for specific spherically symmetric metrics obtaining the velocity of the sound during the process and the critical speed of the flow of the fluid around the black hole. In addition, we study the behaviour of the rate of change of the mass for each chosen metric for a barotropic fluid.Comment: 10 pages, 15 figures, v2 accepted for publication in 'European Physical Journal C