Showing papers by "Ford Motor Company published in 2002"

Human marrow stromal cell therapy for stroke in rat Neurotrophins and functional recovery

Abstract: Objective: To test the effect of IV-injected human bone marrow stromal cells (hMSC) on neurologic functional deficits after stroke in rats. Methods: Rats were subjected to transient middle cerebral artery occlusion and IV injected with 3 × 10 6 hMSC 1 day after stroke. Functional outcome was measured before and 1, 7, and 14 days after stroke. Mixed lymphocyte reaction and the development of cytotoxic T lymphocytes measured the immune rejection of hMSC. A monoclonal antibody specific to human cellular nuclei (mAb1281) was used to identify hMSC and to measure neural phenotype. ELISA analyzed neurotrophin levels in cerebral tissue from hMSC-treated or nontreated rats. Bromodeoxyuridine injections were used to identify newly formed cells. Results: Significant recovery of function was found in rats treated with hMSC at 14 days compared with control rats with ischemia. Few (1 to 5%) hMSC expressed proteins phenotypic of brain parenchymal cells. Brain-derived neurotrophic factor and nerve growth factor significantly increased, and apoptotic cells significantly decreased in the ischemic boundary zone; significantly more bromodeoxyuridine-reactive cells were detected in the subventricular zone of the ischemic hemisphere of rats treated with hMSC. hMSC induced proliferation of lymphocytes without the induction of cytotoxic T lymphocytes. Conclusion: Neurologic benefit resulting from hMSC treatment of stroke in rats may derive from the increase of growth factors in the ischemic tissue, the reduction of apoptosis in the penumbral zone of the lesion, and the proliferation of endogenous cells in the subventricular zone.

Treatment of neural injury with marrow stromal cells

Abstract: Summary We describe our preclinical studies on the use of bone-marrow stromal cells (MSC; an uncharacterised mixed population of plastic-adherent cells) in the treatment of neural injury. These cells obtained from donor rats or human beings have been directly transplanted into brain or administered intra-arterially or intravenously. MSC selectively target injured tissue and promote functional recovery. Signals that target inflammatory cells to injured tissue probably direct MSC to injury sites. Although some MSC express proteins typical of neural cells, the possibility that benefit is derived by replacement of infarcted tissue with differentiated MSC is highly unlikely. MSC activate endogenous restorative responses in injured brain, which include angiogenesis, neurogenesis, and synaptogenesis. Given the robust therapeutic benefit of these cells in the treatment of experimental neural injury, and the fact that MSC have been used in the treatment of other human disease, there is justification for further preclinical studies leading to clinical trials for the treatment of neural injury such as stroke.

Bone Marrow--Derived Endothelial Progenitor Cells Participate in Cerebral Neovascularization After Focal Cerebral Ischemia in the Adult Mouse

Abstract: We investigated whether circulating endothelial progenitor cells contribute to neovascularization after stroke. Donor bone marrow cells obtained from transgenic mice constitutively expressing beta-galactosidase transcriptionally regulated by an endothelial-specific promoter, Tie2, were injected into adult mice. Focal cerebral ischemia was induced by embolic middle cerebral artery (MCA) occlusion and changes of cerebral blood flow (CBF) were measured by perfusion-weighted magnetic resonance imaging (MRI). Laser scanning confocal microscopy (LSCM), immunohistochemistry and X-gal staining were performed. Perfusion-weighted MRI demonstrated increases in CBF around the boundary of an infarct area 1 month after ischemia. Morphological and 3-dimensional image analyses revealed enlarged and thin-walled blood vessels with sprouting or intussusception at the boundary of the ischemic lesion, which closely corresponded to elevated CBF areas detected on perfusion-weighted MRI, indicating the presence of neovascularization. X-gal and double immunostaining demonstrated that Tie2-lacZ-positive cells incorporated into sites of neovascularization at the border of the infarct, and these cells exhibited an endothelial antigenic marker (von Willebrand factor). In addition, bone marrow recipient mice without ischemia showed incorporation of Tie2-lacZ-expressing cells into vessels of the choroid plexus. These data suggest that formation of new blood vessels in the adult brain after stroke is not restricted to angiogenesis but also involves vasculogenesis and that circulating endothelial progenitor cells from bone marrow contribute to the vascular substructure of the choroid plexus.

Exhaust gas aftertreatment systems

Abstract: A method is presented for estimating an amount of ammonia stored in a urea-based SCR catalyst based on a dynamic model of the catalyst. The model takes into account chemical and physical properties of the catalyst, such as catalyst volume, the number of available ammonia storage cites, adsorption and desorption dynamics, as well as poisoning, thermal aging, and different catalyst operating temperatures, and generates the estimate based on a measured or estimated amount of NOx in an exhaust gas mixture upstream of the catalyst, an amount of reductant injected into the catalyst to facilitate NOx reduction, and on a measured value of NOx in an exhaust gas mixture downstream of the catalyst. The estimated ammonia storage amount is then used to control the amount of reductant injected into the catalyst to maintain desired ammonia storage amount such that maximum NOx conversion efficiency coupled with minimum ammonia slip are achieved.

Correlation of VEGF and angiopoietin expression with disruption of blood-brain barrier and angiogenesis after focal cerebral ischemia.

Abstract: In an effort to elucidate the molecular mechanisms underlying cerebral vascular alteration after stroke, the authors measured the spatial and temporal profiles of blood–brain barrier (BBB) leakage, angiogenesis, vascular endothelial growth factor (VEGF), associated receptors, and angiopoietins and receptors after embolic stroke in the rat. Two to four hours after onset of ischemia, VEGF mRNA increased, whereas angiopoietin 1 (Ang 1) mRNA decreased. Three-dimensional immunofluorescent analysis revealed spatial coincidence between increases of VEGF immunoreactivity and BBB leakage in the ischemic core. Two to 28 days after the onset of stroke, increased expression of VEGF/VEGF receptors and Ang/Tie2 was detected at the boundary of the ischemic lesion. Concurrently, enlarged and thin-walled vessels were detected at the boundary of the ischemic lesion, and these vessels developed into smaller vessels via sprouting and intussusception. Three-dimensional quantitative analysis of cerebral vessels at the boundary...

Ischemic rat brain extracts induce human marrow stromal cell growth factor production.

Abstract: Intravenous administration of human bone marrow stromal cells (hMSCs) after middle cerebral artery occlusion (MCAo) in rats provides functional benefit. We tested the hypothesis that these functional benefits are derived in part from hMSC production of growth and trophic factors. Quantitative sandwich enzyme-linked immunosorbent assay (ELISA) of hMSCs cultured with normal and MCAo brain extracts were performed. hMSCs cultured in supernatant derived from ischemic brain extracts increased production of brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF). These neurotrophins and angiogenic growth factors increased in a post-ischemia time-dependent manner. The hMSC capacity to increase expression of growth and trophic factors may be the key to the benefit provided by transplanted hMSCs in the ischemic brain.

On Sequential Sampling for Global Metamodeling in Engineering Design

Abstract: Approximation models (also known as metamodels) have been widely used in engineering design to facilitate analysis and optimization of complex systems that involve computationally expensive simulation programs. The accuracy of metamodels is directly related to the sampling strategies used. Our goal in this paper is to investigate the general applicability of sequential sampling for creating global metamodels. Various sequential sampling approaches are reviewed and new approaches are proposed. The performances of these approaches are investigated against that of the one-stage approach using a set of test problems with a variety of features. The potential usages of sequential sampling strategies are also discussed.Copyright © 2002 by ASME

Human bone marrow stromal cell cultures conditioned by traumatic brain tissue extracts: growth factor production.

Abstract: Treatment of traumatic brain injury (TBI) with bone marrow stromal cells (MSCs) improves functional outcome in the rat. However, the specific mechanisms by which introduced MSCs provide benefit remain to be elucidated. Currently, the ability of therapeutically transplanted MSCs to replace injured parenchymal CNS tissue appears limited at best. Tissue replacement, however, is not the only possible compensatory avenue in cell transplantation therapy. Various growth factors have been shown to mediate the repair and replacement of damaged tissue, so trophic support provided by transplanted MSCs may play a role in the treatment of damaged tissue. We therefore investigated the temporal profile of various growth factors, brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), and hepatocyte growth factor (HGF), within cultures of human MSCs (hMSCs) conditioned with cerebral tissue extract from TBI. hMSCs were cultured with TBI extracts of rat brain in vitro and quantitative sandwich enzyme-linked immunosorbent assays (ELISAs) were performed. TBI-conditioned hMSCs cultures demonstrated a time-dependent increase of BDNF, NGF, VEGF, and HGF, indicating a responsive production of these growth factors by the hMSCs. The ELISA data suggest that transplanted hMSCs may provide therapeutic benefit via a responsive secretion of an array of growth factors that can foster neuroprotection and angiogenesis.

Magnetostrictive phenomena in magnetorheological elastomers

Abstract: A host of fascinating and useful magnetic phenomena are found in composites containing magnetizable particles in viscoelastic solids. Embedding magnetically soft iron particles in natural rubber produces a class of magnetostrictive composites sometimes termed magnetorheological (MR) elastomers. We have previously shown that these materials can exhibit viscoelastic moduli that increase substantially in an applied magnetic field. In this paper, we incorporate MR elastomers in a simple resonant structure called a tuned absorber to measure the complex dynamic shear moduli of these materials at high frequencies. We find that the fluid-induced modulus increase in MR elastomers is substantial even at kilohertz mechanical frequencies. As in previous measurements at low frequencies, the moduli are generally found to decrease with strain amplitude. We also report preliminary measurements of the relatively large elongation of these materials in applied magnetic fields.

Blind-spot warning system for an automotive vehicle

Abstract: A host vehicle system includes a blind-spot warning system providing an indication to the host vehicle a target vehicle entering a blind-spot. The system includes a vehicle bus receiving various vehicle control signals, magneto-resistive sensors receiving proximity information as a function of magnetic field variations, a smart algorithm controller analyzing bus signals and sensor signals, and various vehicle collision systems such as passive restraints, optical light guides, and audible warnings operating in response to a threat from a target vehicle.

MCP-1, MIP-1, IL-8 and Ischemic Cerebral Tissue Enhance Human Bone Marrow Stromal Cell Migration in Interface Culture

Abstract: Bone marrow stromal cells (MSCs) administered intravenously are effective in reducing neurological deficits after stroke in the rodent. These cells appear to selectively migrate and express neural phenotypes in ischemic brain. To elucidate the mechanisms targeting MSC migration into the ischemic brain, we measured, using a microchemotaxis chamber, the effect of select chemotactic factors and cytokines expressed in injured brain, monocyte chemoattractant protein-1 (MCP-1), macrophage inflammatory protein-1α (MIP-1α) and interleukin-8 (IL-8), on migration of human bone marrow stromal cells (hMSCs). In addition, we investigated whether tissue extracts prepared from rat ischemic brain at various times after middle cerebral artery occlusion (MCAo) induce migration of hMSCs. Our data indicate that MCP-1, MIP-1α and IL-8 enhance the migration of hMSCs. Ischemic brain tissue extracts at 24, 48 h and 1 week after ischemia significantly increase hMSC migration across the membrane compared to non-ischemic ti...

An adaptive peer-to-peer collision warning system

Abstract: A cooperative vehicle collision warning system is made possible by the progress in advanced positioning systems and wireless communication technology. We report our work in developing a cooperative intersection collision warning system that is not limited by the requirement of line-of-sight. The novel elements of the system include the use of a dynamic ad hoc wireless network for peer-to-peer data sharing, a new intersection collision warning algorithm, and a flexible and extensible software architecture and system design. The very same system is also capable of collision warning for other scenarios such as frontal and rear-end. Further, the tunable parameters in the algorithm make it possible for the system to adapt to the preference and capability of each individual driver.

On-road vehicle detection using Gabor filters and support vector machines

Abstract: On-road vehicle detection is an important problem with application to driver assistance systems and autonomous, self-guided vehicles. The focus of this paper is on the problem of feature extraction and classification for rear-view vehicle detection. Specifically, we propose using Gabor filters for vehicle feature extraction and support vector machines (SVM) for vehicle detection. Gabor filters provide a mechanism for obtaining some degree of invariance to intensity due to global illumination, selectivity in scale, and selectivity in orientation. Basically, they are orientation and scale tunable edge and line detectors. Vehicles do contain strong edges and lines at different orientation and scales, thus, the statistics of these features (e.g., mean, standard deviation, and skewness) could be very powerful for vehicle detection. To provide robustness, these statistics are not extracted from the whole image but rather are collected from several subimages obtained by subdividing the original image into subwindows. These features are then used to train a SVM classifier. Extensive experimentation and comparisons using real data, different features (e.g., based on principal components analysis (PCA)), and different classifiers (e.g., neural networks (NN)) demonstrate the superiority of the proposed approach which has achieved an average accuracy of 94.81% on completely novel test images.

Functional MRI-BOLD of brainstem structures during visually triggered migraine

Abstract: Background: Previously, hyperoxia and blood volume increase were reported in the red nucleus and substantia nigra during spontaneous migraine with aura. Objective: To further understand the pathophysiologic role of these centers, activation of brainstem structures was investigated in patients with visually triggered migraine. Methods: Twenty-six patients with migraine (23 with aura and 3 without aura), and 10 normal control subjects were studied with blood oxygen level–dependent (BOLD) fMRI during repeated checkerboard visual stimulation. Three axial image sections, which covered the occipital cortex and brainstem, were acquired 224 times with a temporal resolution of 3.5 seconds. Results: Repetitive visual stimulation triggered symptoms in 12 patients; four who had migraine with aura developed both visual symptoms and headaches, and six who had migraine with aura and two who had migraine without aura had headaches only. Four patients who had migraine with aura experienced the onset of their usual aura or onset of their typical headache either during the experiment or immediately after. In the remaining 10 patients with migraine, and all control subjects, visual stimulation failed to trigger symptoms at any time. In 75% of the patients who developed symptoms during stimulation, baseline T2*-weighted MR signal intensities increased in the red nucleus and substantia nigra before occipital cortex signal elevation or the onset of visually triggered symptoms. Conclusion: Activation (hyperoxia and blood volume increase) of the red nucleus and substantia nigra in association with visually triggered symptoms of migraine suggest that these brainstem structures are a part of a neuronal network activated during an attack.

The effects of the catalytic converter and fuel sulfur level on motor vehicle particulate matter emissions: light duty diesel vehicles.

Abstract: Wind tunnel measurements and direct tailpipe particulate matter (PM) sampling are utilized to examine how the combination of oxidation catalyst and fuel sulfur content affects the nature and quantity of PM emissions from the exhaust of a light duty diesel truck. When low sulfur fuel (4 ppm) is used, or when high sulfur (350 ppm) fuel is employed without an active catalyst present, a single log-normal distribution of exhaust particles is observed with a number mean diameter in the range of 70−83 nm. In the absence of the oxidation catalyst, the high sulfur level has at most a modest effect on particle emissions (<50%) and a minor effect on particle size (<5%). In combination with the active oxidation catalyst tested, high sulfur fuel can lead to a second, nanoparticle, mode, which appears at ∼20 nm during high speed operation (70 mph), but is not present at low speed (40 mph). A thermodenuder significantly reduces the nanoparticle mode when set to temperatures above ∼200 °C, suggesting that these particles...

Regenerative braking system for a hybrid electric vehicle

Abstract: This paper discusses a regenerative braking system (RBS) for a parallel hybrid electric vehicle (PHEV) that performs regenerative energy recovery based on vehicle attributes, thereby providing improved performance, efficiency and reliability at minimal additional cost. A detailed description of the regenerative braking algorithm is presented along with simulation results from a dynamic model of the PHEV exhibiting the regenerative braking performance.

Collision warning and safety countermeasure system

Abstract: A collision warning and safety countermeasure system ( 10 ) for an automotive vehicle ( 12 ) having a vehicle sensor complex ( 18 ) and generating a vehicle sensor complex signal is provided. The system ( 10 ) includes a sensor fusion ( 14 ) that generates an object status signal. A threat assessor ( 16 ) generates a vehicle status signal in response to the vehicle sensor complex signal. The threat assessor ( 16 ) also in response to the vehicle status signal and the object status signal generates a collision assessment signal. An active countermeasure controller ( 20 ) generates an active countermeasure signal in response to the collision assessment signal and the vehicle sensor complex signal. A passive countermeasure controller ( 22 ) generates a passive countermeasure signal in response to the collision assessment signal and the vehicle sensor complex signal. An indicator ( 30 ) generates a collision-warning signal in response to the collision assessment signal. A method for performing the same is also provided.