This paper presents a methodology to simulate discrete fracture networks for naturally fractured ... more This paper presents a methodology to simulate discrete fracture networks for naturally fractured reservoirs by combining statistical and spatial analyses, object-based modelling and conditional global optimisation. The methodology examines and utilises both continuum and discrete fracture information, such as spatial distribution of fracture density, statistical and geostatistical distributions of fracture size and orientation. The output is a network of discrete fractures, with their corresponding details of location, size and orientation. The methodology is illustrated by a case study on the surface fault system in New York region. The results show that it is able to produce discrete fracture network that match closely to the target fault map, even in the case where data are limited. The results show that it is also able to improve results of several recent fracture models, such as integrated stochastic simulations as well as grid-based simulations.
... its own public/private key pair which will form the basis for the user's or organisa... more ... its own public/private key pair which will form the basis for the user's or organisation's digital identity in the e-commerce ... environment. ... and trustworthiness in an automated and mechanical fashion, but present implementations are based on a very limited trust model making them ...
Both in utero and postnatal hematopoietic stem cell (HSC) transplantation would benefit from the ... more Both in utero and postnatal hematopoietic stem cell (HSC) transplantation would benefit from the development of approaches that produce increased levels of engraftment or a reduction in the period of time required for reconstitution. We used the in utero model of human-sheep HSC transplantation to investigate ways of improving engraftment and differentiation of donor cells after transplantation. We hypothesized that providing a more suitable microenvironment in the form of human stromal cell progenitors simultaneously with the transplanted human HSC would result in higher rates of engraftment or differentiation of the human cells in this xenogeneic model. The results presented here demonstrate that the cotransplantation of both autologous and allogeneic human bone marrow-derived stromal cell progenitors resulted in an enhancement of long-term engraftment of human cells in the bone marrow of the chimeric animals and in earlier and higher levels of donor cells in circulation both during gestation and after birth. By using marked stromal cells, we have also demonstrated that injected stromal cells alone engraft and remain functional within the sheep hematopoietic microenvironment. Application of this method to clinical HSC transplantation could potentially lead to increased levels of long-term engraftment, a reduction in the time for hematopoietic reconstitution, and a means of delivery of foreign genes to the hematopoietic system.
We investigated whether directly injecting retroviral vectors into preimmune fetuses could result... more We investigated whether directly injecting retroviral vectors into preimmune fetuses could result in the transfer and long-term expression of exogenous genes. Twenty-nine preimmune sheep fetuses were injected with helper-free retroviral vector preparations. Twenty-two fetuses survived to term, 4 of which were sacrificed at birth. Of the remaining 18 animals, 3 were controls and 15 had received vector preparations. Twelve of these 15 animals demonstrated transduction of hematopoietic cells when blood and marrow were analyzed by neo(r)-specific PCR. Eight experimental sheep have been followed for 5 years, during which time we have consistently observed proviral DNA and G418-resistant hematopoetic progenitors. The G418-resistant colonies were positive when analyzed by neo(r)-specific PCR. neo(r) gene expression was also demonstrated using several immunological and biochemical methods. The transduction of hematopoietic stem cells was confirmed when lambs transplanted with bone marrow from in utero-transduced sheep exhibited neo(r) activity in marrow and blood. Vector distribution was widespread in primary animals without pathology. PCR analysis indicates that the germ line was not altered. These studies demonstrate that direct injection of an engineered retrovirus is a feasible means of safely delivering a foreign gene to a developing fetus and achieving long-term expression without modifying the germ line of the recipient.
This paper advances the fundamental understanding in mathematical and computational modelling of ... more This paper advances the fundamental understanding in mathematical and computational modelling of discrete fracture networks (Type I). It presents a systematic procedure to solve the most important problem in modelling by global optimization objective function formulation, which ...
A significant number of petroleum and almost all geothermal reservoirs are characterised by high ... more A significant number of petroleum and almost all geothermal reservoirs are characterised by high in‐situ stress and fractures where fractures act as major flow paths for fluids. An integrated tensor model is proposed to solve three tasks: characterisation of ...
The purpose of this in vivo MRI study was to quantify changes in atherosclerotic plaque morpholog... more The purpose of this in vivo MRI study was to quantify changes in atherosclerotic plaque morphology prospectively and to identify factors that may alter the rate of progression in plaque burden. Sixty-eight asymptomatic subjects with ≥50% stenosis, underwent serial carotid MRI examinations over an 18-month period. Clinical risk factors for atherosclerosis, and medications were documented prospectively. The wall and total vessel areas, matched across time-points, were measured from cross-sectional images. The normalized wall index (NWI = wall area/total vessel area), as a marker of disease severity, was documented at baseline and at 18 months. Multiple regression analysis was used to correlate risk factors and morphological features of the plaque with the rate of progression/regression.On average, the wall area increased by 2.2% per year (P = 0.001). Multiple regression analysis demonstrated that statin therapy (P = 0.01) and a normalized wall index >0.64 (P = 0.001) were associated with a significantly reduced rate of progression in mean wall area. All other documented risk factors were not significantly associated with changes in wall area. Findings from this study suggest that increased normalized wall index and the use of statin therapy are associated with reduced rates of plaque progression amongst individuals with advanced, asymptomatic carotid atherosclerosis.
This paper presents a methodology to simulate discrete fracture networks for naturally fractured ... more This paper presents a methodology to simulate discrete fracture networks for naturally fractured reservoirs by combining statistical and spatial analyses, object-based modelling and conditional global optimisation. The methodology examines and utilises both continuum and discrete fracture information, such as spatial distribution of fracture density, statistical and geostatistical distributions of fracture size and orientation. The output is a network of discrete fractures, with their corresponding details of location, size and orientation. The methodology is illustrated by a case study on the surface fault system in New York region. The results show that it is able to produce discrete fracture network that match closely to the target fault map, even in the case where data are limited. The results show that it is also able to improve results of several recent fracture models, such as integrated stochastic simulations as well as grid-based simulations.
... its own public/private key pair which will form the basis for the user's or organisa... more ... its own public/private key pair which will form the basis for the user's or organisation's digital identity in the e-commerce ... environment. ... and trustworthiness in an automated and mechanical fashion, but present implementations are based on a very limited trust model making them ...
Both in utero and postnatal hematopoietic stem cell (HSC) transplantation would benefit from the ... more Both in utero and postnatal hematopoietic stem cell (HSC) transplantation would benefit from the development of approaches that produce increased levels of engraftment or a reduction in the period of time required for reconstitution. We used the in utero model of human-sheep HSC transplantation to investigate ways of improving engraftment and differentiation of donor cells after transplantation. We hypothesized that providing a more suitable microenvironment in the form of human stromal cell progenitors simultaneously with the transplanted human HSC would result in higher rates of engraftment or differentiation of the human cells in this xenogeneic model. The results presented here demonstrate that the cotransplantation of both autologous and allogeneic human bone marrow-derived stromal cell progenitors resulted in an enhancement of long-term engraftment of human cells in the bone marrow of the chimeric animals and in earlier and higher levels of donor cells in circulation both during gestation and after birth. By using marked stromal cells, we have also demonstrated that injected stromal cells alone engraft and remain functional within the sheep hematopoietic microenvironment. Application of this method to clinical HSC transplantation could potentially lead to increased levels of long-term engraftment, a reduction in the time for hematopoietic reconstitution, and a means of delivery of foreign genes to the hematopoietic system.
We investigated whether directly injecting retroviral vectors into preimmune fetuses could result... more We investigated whether directly injecting retroviral vectors into preimmune fetuses could result in the transfer and long-term expression of exogenous genes. Twenty-nine preimmune sheep fetuses were injected with helper-free retroviral vector preparations. Twenty-two fetuses survived to term, 4 of which were sacrificed at birth. Of the remaining 18 animals, 3 were controls and 15 had received vector preparations. Twelve of these 15 animals demonstrated transduction of hematopoietic cells when blood and marrow were analyzed by neo(r)-specific PCR. Eight experimental sheep have been followed for 5 years, during which time we have consistently observed proviral DNA and G418-resistant hematopoetic progenitors. The G418-resistant colonies were positive when analyzed by neo(r)-specific PCR. neo(r) gene expression was also demonstrated using several immunological and biochemical methods. The transduction of hematopoietic stem cells was confirmed when lambs transplanted with bone marrow from in utero-transduced sheep exhibited neo(r) activity in marrow and blood. Vector distribution was widespread in primary animals without pathology. PCR analysis indicates that the germ line was not altered. These studies demonstrate that direct injection of an engineered retrovirus is a feasible means of safely delivering a foreign gene to a developing fetus and achieving long-term expression without modifying the germ line of the recipient.
This paper advances the fundamental understanding in mathematical and computational modelling of ... more This paper advances the fundamental understanding in mathematical and computational modelling of discrete fracture networks (Type I). It presents a systematic procedure to solve the most important problem in modelling by global optimization objective function formulation, which ...
A significant number of petroleum and almost all geothermal reservoirs are characterised by high ... more A significant number of petroleum and almost all geothermal reservoirs are characterised by high in‐situ stress and fractures where fractures act as major flow paths for fluids. An integrated tensor model is proposed to solve three tasks: characterisation of ...
The purpose of this in vivo MRI study was to quantify changes in atherosclerotic plaque morpholog... more The purpose of this in vivo MRI study was to quantify changes in atherosclerotic plaque morphology prospectively and to identify factors that may alter the rate of progression in plaque burden. Sixty-eight asymptomatic subjects with ≥50% stenosis, underwent serial carotid MRI examinations over an 18-month period. Clinical risk factors for atherosclerosis, and medications were documented prospectively. The wall and total vessel areas, matched across time-points, were measured from cross-sectional images. The normalized wall index (NWI = wall area/total vessel area), as a marker of disease severity, was documented at baseline and at 18 months. Multiple regression analysis was used to correlate risk factors and morphological features of the plaque with the rate of progression/regression.On average, the wall area increased by 2.2% per year (P = 0.001). Multiple regression analysis demonstrated that statin therapy (P = 0.01) and a normalized wall index >0.64 (P = 0.001) were associated with a significantly reduced rate of progression in mean wall area. All other documented risk factors were not significantly associated with changes in wall area. Findings from this study suggest that increased normalized wall index and the use of statin therapy are associated with reduced rates of plaque progression amongst individuals with advanced, asymptomatic carotid atherosclerosis.
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