218 research outputs found
Learning Bloch Simulations for MR Fingerprinting by Invertible Neural Networks
No full textMagnetic resonance fingerprinting (MRF) enables fast and multiparametric MR imaging. Despite fast acquisition, the state-of-the-art reconstruction of MRF based on dictionary matching is slow and lacks scalability. To overcome these limitations, neural network (NN) approaches estimating MR parameters from fingerprints have been proposed recently. Here, we revisit NN-based MRF reconstruction to jointly learn the forward process from MR parameters to fingerprints and the backward process from fingerprints to MR parameters by leveraging invertible neural networks (INNs). As a proof-of-concept, we perform various experiments showing the benefit of learning the forward process, i.e., the Bloch simulations, for improved MR parameter estimation. The benefit especially accentuates when MR parameter estimation is difficult due to MR physical restrictions. Therefore, INNs might be a feasible alternative to the current solely backward-based NNs for MRF reconstruction
Quantitative modeling of epileptic seizures and interictal events
No full textA quantitative analysis of the dynamics of generalized epileptic seizures is carried out by using a neural field model of the corticothalamic system in the presence of a temporally varying connection strength between the cerebral cortex and thalamus. The temporal and dynamical characteristics of generalized absence seizure and tonic-clonic seizures and the interictal oscillations in between two successive seizures are analyzed and related to the corresponding physiological changes of the connection strength. It is found that the spectral, temporal, and physiological characteristics of seizure oscillations changes with the rate of change and amplitude of the connection strength, including appearance of a saddle-cycle at high ramp rates in the tonic-clonic case. The transitions between different states during seizures are inversely proportional to the square root of the ramp rate. The amplitude and sharpness of the interictal oscillations increase with the maximum connection strength, and the number of oscillations only depends on the duration above the threshold
The assessment, impact and management of psychological reactions to trauma among Bangladeshi children
No full textTheoretical thesis.Includes bibliographical references.Chapter 1. Introduction -- Chapter 2. Psychometric properties of children's revised impact of event scale (cries) with Bangladeshi children and adolescents -- Chapter 3. Psychometric properties of two measures of childhood internalising problems in a Bangladeshi sample -- Chapter 4. Prevalence of traumatic events and risk for psychological symptoms among community and at-risk children and adolescents from Bangladesh -- Chapter 5. Evaluating an innovative intervention for traumatized children in a low resourced country -- Chapter 6. Summary and conclusion.According to theory and empirical research, traumatic experiences early in life can lead to greater impact on an individual than traumas occurring in adulthood. Traumatic events among young people are common with one in every four children living in a developing country being likely to experience a traumatic event by the time they are 18 years old. However, due to a variety of social, economic and environmental disadvantages, children from developing countries are at even greater risk of trauma exposure. The research in this thesis comprised samples of children and adolescents from Bangladesh, a developing world country that differs from the developed world not only on socio-economic grounds but also in cultural factors including language, traditions and religions.Mode of access: World wide web1 online resource (xxi, 294 pages) diagrams, table
A multimodal approach for placenta characterization : towards an objective and effective pregnancy screening system
No full textRecent developments in the understanding of the role of the placenta as the ‘master regulator’ of the intra-uterine environment underline the importance of placental evaluation in pregnancy screening. The placenta plays a major role in the pathogenesis of many pregnancy complications such as preeclampsia (PE) and intrauterine growth restriction (IUGR). These complications are leading causes of maternal and perinatal mortality and morbidity, affecting as many as 34% of all pregnancies. Antenatal monitoring of placentas using non-invasive, real time imaging techniques
could potentially identify sensitive biomarkers of placental health and thereby offer opportunity for early intervention enabling improved perinatal outcomes. The overarching objective of this thesis is to develop an effective and objective pregnancy screening system. To attain this objective, the first part of the thesis focused on the theoretical development of several user- and system-independent
Quantitative Ultrasound (QUS) algorithms. Different approaches were adopted for improved QUS estimation by addressing the fundamental precision-resolution trade-off and effect of tissue heterogeneity. Particularly, we proposed a prior-based regularization technique, the prior being derived from ultrasound physics, and a deep learning based approach, predictUS. In the second part of the thesis, a multimodal placental imaging study, including the ultrasound, MRI, and histopathology data from 47 placentas ex vivo, was designed and conducted in collaboration with a multi-disciplinary team. The dataset from this study was utilized for the validation of the proposed QUS algorithms. Specifically, we analyzed the efficacy of different QUS parameters, including
attenuation coefficient, backscatter coefficient, scatterer diameter, elasticity, and viscosity, to detect placenta-mediated diseases and clinical outcomes.Applied Science, Faculty ofElectrical and Computer Engineering, Department ofGraduat
Islamic Feminism: Gender Equity By Deconstructing Tradition
Get PDFModernity coupled with Industrial Revolution and raising secularism paved way for a new ensemble of social unity. Individualism that penetrated the core of modern society brought many changes to the application of many pre-modern values like justice, equality and liberty. From such passage from pre-modern to modern world we witness the birth of one of the most influential movements in modern world on the level of social dynamics; Feminism. Feminism started its treatment of women under the banner of secular feminism but soon it died out because of Muslim society’s civilizational context, which was unlike Christianity. Secular feminism feed a catalyst to the contemporary Muslim woman thinkers who later on came up with the more intellectual and academic approach to secular feminism called; Islamic Feminism. Islamic Feminism maidenly raised the question on masculine interpretations of Sacred Text. Inclusion of feminine voice in reinterpretation of the Holy Scripture rendered the underlined meanings of gender which launched a potent discourse on gender equity within the Islamic framework in traditional society. The purpose of this paper is to present the contribution of Islamic Feminism in the exploration of lost reality of Islamic egalitarian society by conducting content analysis
The assessment, impact and management of psychological reactions to trauma among Bangladeshi children
No full textAccording to theory and empirical research, traumatic experiences early in life can lead to greater impact on an individual than traumas occurring in adulthood. Traumatic events among young people are common with one in every four children living in a developing country being likely to experience a traumatic event by the time they are 18 years old. However, due to a variety of social, economic and environmental disadvantages, children from developing countries are at even greater risk of trauma exposure. The research in this thesis comprised samples of children and adolescents from Bangladesh, a developing world country that differs from the developed world not only on socio-economic grounds but also in cultural factors including language, traditions and religions
Vibrational spectroscopy to monitor controlled drug release from hydrophilic matrices
Get PDFApproximately 40% of drugs currently marketed and 90% of all drugs under development
show poor and varied aqueous solubility at the different pH values encountered along
the gastrointestinal tract. The pH-dependent release profile exhibited by these drugs
often leads to poor bioavailability and ultimately means that many do not make it to
licence. To mitigate against this and to inform future drug development, it is important to
understand the dissolution behaviour of these types of drugs at a molecular level.
This thesis explores the use of ATR-FTIR imaging to gain an insight into the within-tablet
dynamics of a sparingly soluble, weakly basic drug that has been incorporated into a
hydrophilic matrix. This approach provides a chemical insight into the nature of drug,
polymer matrix, excipients and water in a formulation undergoing dynamic changes
including ionisation, dissolution, hydration, swelling and particle dislocation. Specifically,
this work uses tablets manufactured using an HPMC polymer matrix incorporating 20%
w/w itraconazole as the model drug which has a pKa of 3.7 and is practically insoluble
at pH 7, both with and without the addition of the organic acid modifiers (citric acid,
betaine HCl, cysteine HCl and glycine HCl) to control the local pH.
In placebo HPMC tablets, ATR-FTIR imaging, supplemented by optical imaging, showed
that hydration and swelling was independent of the pH of the media. However, when the
ionic strength of the hydrating medium was adjusted, rapid formation of the gel layer was
observed at low ionic strength, while increased ionic strength was shown to interfere with
HPMC hydration, resulting in the suppression of the expansion of the gel layer.
Hydration and dissolution studies conducted on HPMC tablets loaded with 20% w/w IT
were limited to the use of low ionic strength media only. From the dissolution studies, the
release of IT from these tablets was shown to be significantly greater at pH 1.5 when
compared with that at pH 7. Optical measurements showed that the swelling of 20% w/w
IT loaded HPMC tablets was greater at pH 1.5 over the period of the hydration in
comparison to the pH 7 environment. ATR-FTIR imaging data revealed that at pH 1.5
the IT was ionised, becoming soluble and there was evidence of IT particle translocation
into the diffusion front and eventually out into the surrounding medium. However, at pH
7, the IT remained in the free base form, largely within the tablet core and the swelling
front, with less evidence of IT particle translocation. From both the optical measurements
and ATR-FTIR imaging studies, it was shown that the swelling capacity of the gel layer
in IT loaded tablets was reduced at pH 7 in comparison to pH 1.5 indicating that the poor
solubility of IT retarded hydration.
Exploring the impact of organic pH modifiers on the release of IT from the HPMC matrix
at a 10% w/w and 30% w/w loading, enhanced dissolution at pH 7 of the IT was observed
in comparison to tablets without any modifier. From both the optical imaging and ATRFTIR
imaging data, the gel layer expansion was shown to be greater at higher pH
modifier loading for all systems. However, the magnitude of swelling differed between
the modifier systems over the hydration period and a greater amount of swelling was
observed with the betaine HCl and citric acid in comparison to the cysteine HCl and
glycine HCl. The results indicated that, of the organic acid modifiers selected, tablets
containing cysteine HCl provided the greatest enhancement of release of IT. These
findings were consistent with the ATR-FTIR imaging results, where the greatest
reduction in the intensity of the spectral band assigned to the free base form of IT, was
also observed in tablets containing the cysteine HCl modifier
Preliminary adaptation of cognitive behavioral therapy for major depression in the Bangladeshi context: a pilot study
No full textAbstract Cultural values and standard social rules of communities strongly influence any psychological therapy. Being developed and modified in the Western world, cognitive behavior therapy (CBT) is not anyway different from such influences. In this study, CBT was adapted in Bengali to determine the functional feasibility of the psychological intervention for people with depression in Bangladesh. This is the first pilot study of an adapted CBT manual for psychological intervention for working with depressive clients in Bangladesh. There were three phases of the study. In the first two phases, the standard protocols of CBT were adapted for the Bangladeshi community, as practiced by mainstream practitioners and mental health professionals around the world. The information gathered during the first phase of the standard protocols of CBT was written in Bengali as the first draft. In the second phase, the CBT manual was judged by seven senior clinical psychologists in Bangladesh who were trained in CBT by British clinical psychologists and later provided training to fellow mental health professionals. After the judges’ evaluation, their comments and suggestions were synthesized and the first draft of the adapted intervention was finalized. In the third phase, to evaluate the functional feasibility of the Bengali CBT-based manual, five patients diagnosed with major depression by psychiatrists were tested. Four valid and reliable psychometric measurements were used to measure symptoms of depression and comorbid symptoms of anxiety, psychological distress, and suicidal risk. Assessments were completed at 2 time points (pretest and posttest) via scales. The intervention was delivered within 6 to 10 sessions, and improvements were monitored over the scores of all the questionnaires. The possibilities of Bengali CBTs to reduce depression and appear to be promising treatment options for depression are discussed in this paper
- …
