Pierre Garcia - Academia.edu (original) (raw)

Papers by Pierre Garcia

Tonatiuh is an Open Source, Monte-Carlo ray tracer, object-oriented computer program for the desi... more Tonatiuh is an Open Source, Monte-Carlo ray tracer, object-oriented computer program for the design, simulation, and analysis of the optical and energy behavior of solar concentrating systems, which is being developed by the National Renewable Energy Centre of Spain (CENER) in collaboration with the University of Texas at Brownsville (UTB), with the support of the National Renewable Energy Laboratory (NREL). This paper presents the results of a preliminary comparison among Tonatiuh and another state-of-the-art computer code: SolTrace, developed by NREL. These results provide solid evidence that the current release of Tonatiuh does a good job in simulating the optical behavior of single and multi-reflections solar concentrating systems.

This paper presents a validation of DinaCET using experimental data from more than one year opera... more This paper presents a validation of DinaCET using experimental data from more than one year operation of the Nevada Solar One power plant. DinaCET is a computational scheme for the generation of stand-alone dynamic computer programs that simulate the transient behavior of parabolic trough solar thermal power plants. The programs generated by DinaCET are able to simulate a defined power plant, with a given collector field and power block configuration and layout. DinaCET allows the user to define a large range of parameters relevant for detailed simulations, from collector’s geometry and materials to temperature and control system characteristics.

Journal of Neuroscience, 2010

The development of novel therapeutic strategies for Alzheimer&amp... more The development of novel therapeutic strategies for Alzheimer's disease (AD) represents one of the biggest unmet medical needs today. Application of neurotrophic factors able to modulate neuronal survival and synaptic connectivity is a promising therapeutic approach for AD. We aimed to determine whether the loco-regional delivery of ciliary neurotrophic factor (CNTF) could prevent amyloid-beta (Abeta) oligomer-induced synaptic damages and associated cognitive impairments that typify AD. To ensure long-term administration of CNTF in the brain, we used recombinant cells secreting CNTF encapsulated in alginate polymers. The implantation of these bioreactors in the brain of Abeta oligomer-infused mice led to a continuous secretion of recombinant CNTF and was associated with the robust improvement of cognitive performances. Most importantly, CNTF led to full recovery of cognitive functions associated with the stabilization of synaptic protein levels in the Tg2576 AD mouse model. In vitro as well as in vivo, CNTF activated a Janus kinase/signal transducer and activator of transcription-mediated survival pathway that prevented synaptic and neuronal degeneration. These preclinical studies suggest that CNTF and/or CNTF receptor-associated pathways may have AD-modifying activity through protection against progressive Abeta-related memory deficits. Our data also encourage additional exploration of ex vivo gene transfer for the prevention and/or treatment of AD.

Solar Energy, 2012

Abstract This paper analyzes the influence of operational strategies on the performance of parabo... more Abstract This paper analyzes the influence of operational strategies on the performance of parabolic trough (PT) solar power plants with the aid of SimulCET a computer program for the simulation of the energy behavior of PT plants developed by the National Renewable ...

Neurobiology of Aging, 2012

Soluble beta-amyloid (Aβ) oligomers are considered to putatively play a critical role in the earl... more Soluble beta-amyloid (Aβ) oligomers are considered to putatively play a critical role in the early synapse loss and cognitive impairment observed in Alzheimer's disease. We previously demonstrated that Aβ oligomers activate cytosolic phospholipase A(2) (cPLA(2)), which specifically releases arachidonic acid from membrane phospholipids. We here observed that cPLA(2) gene inactivation prevented the alterations of cognitive abilities and the reduction of hippocampal synaptic markers levels noticed upon a single intracerebroventricular injection of Aβ oligomers in wild type mice. We further demonstrated that the Aβ oligomer-induced sphingomyelinase activation was suppressed and that phosphorylation of Akt/protein kinase B (PKB) was preserved in neuronal cells isolated from cPLA(2)(-/-) mice. Interestingly, expression of the Aβ precursor protein (APP) was reduced in hippocampus homogenates and neuronal cells from cPLA(2)(-/-) mice, but the relationship with the resistance of these mice to the Aβ oligomer toxicity requires further investigation. These results therefore show that cPLA(2) plays a key role in the Aβ oligomer-associated neurodegeneration, and as such represents a potential therapeutic target for the treatment of Alzheimer's disease.

Journal of Stroke and Cerebrovascular Diseases, 2013

Background: Frequencies of cognitive impairment and dementia have not been assessed in spontaneou... more Background: Frequencies of cognitive impairment and dementia have not been assessed in spontaneous intracerebral hemorrhage (ICH). The objective of this study was to determine the frequencies and patterns of cognitive impairment and dementia in a cross-sectional study of consecutive patients hospitalized in a single university medical center. Methods: Of 183 consecutive patients hospitalized

Journal of Solar Energy Engineering, 2008

Journal of Neurology, Neurosurgery & Psychiatry, 2006

... User Name. Password. Remember me. Forgot your sign in details? Email Alert Signup. BMJ Career... more ... User Name. Password. Remember me. Forgot your sign in details? Email Alert Signup. BMJ Careers - Latest Neurology and Neurosurgery jobs. Latest neurology and neurosurgery jobs. Show me all Neurology jobs >>. Online ISSN 1468-330X. ...

IEEE Transactions on Nuclear Science, 2000

... Y. Calzavara is with the Valduc CEA Research Center, DRMN/SRNC, 21120 Is sur Tille, France (e... more ... Y. Calzavara is with the Valduc CEA Research Center, DRMN/SRNC, 21120 Is sur Tille, France (e-mail: yoann.calzavara@cea.fr). ... Sci., vol. 43, no. 6, pp. 2742–2750, Dec. 1996. [4] EL Petersen, “Nuclear reactions in semiconductors,” IEEE Trans. Nucl. Sci., vol. 27, no. 6, pp. ...

IEEE Transactions on Nuclear Science, 2000

The possibility to monitor pulsed dose-rate facilities by means of real-time fibered dosimetry is... more The possibility to monitor pulsed dose-rate facilities by means of real-time fibered dosimetry is investigated. A system based on the luminescence of the SrS:Ce,Sm is used to monitor pulses from a medical accelerator with four different dose-rates. The RL signal is characterized using a dedicated acquisition system. The RL recorded is linear with dose-rate and dose. The stem effect due to both Cerenkov emission and photoluminescence in the fiber was also investigated with 18 MV photons and 12 MeV electrons.

IEEE Transactions on Nuclear Science, 2000

A novel real-time optical fibered dosimetry system based on optically stimulated luminescence (OS... more A novel real-time optical fibered dosimetry system based on optically stimulated luminescence (OSL) of SrS:Ce,Sm phosphor was developed and is presented. The advantages of this system are the combination of OSL and optical fibers, immediate readout, simplicity of use, low cost, reliability, flexibility, and robustness. Experimental results show an excellent linearity with the dose (0.01 to 6 Gy), repeatability better than 2%, radiation sensitivity up to 80 mV.cGy -1 and accuracy since error on dose is less than 5%. The applications targeted are the measurement of the dose delivered during a treatment in radiation therapy and the monitoring of the dose or dose-rate around or in nuclear reactor and accelerator facilities in high energy physics. Further experiments are still to be conducted in order to fully characterize the system and evaluate the feasibility of each application mentioned.

IEEE Transactions on Nuclear Science, 2000

The possibility to evaluate simultaneously the total ionizing dose and the displacement damage do... more The possibility to evaluate simultaneously the total ionizing dose and the displacement damage dose using a single OSL integrated sensor is demonstrated. Results obtained during the real time monitoring of both proton and electron beams are presented

Biochimie, 2009

In the absence of efficient diagnostic and therapeutic tools, Alzheimer's disease (AD) is a major... more In the absence of efficient diagnostic and therapeutic tools, Alzheimer's disease (AD) is a major public health concern due to longer life expectancy in the Western countries. Although the precise cause of AD is still unknown, soluble b-amyloid (Ab) oligomers are considered the proximate effectors of the synaptic injury and neuronal death occurring in the early stages of AD. Ab oligomers may directly interact with the synaptic membrane, leading to impairment of synaptic functions and subsequent signalling pathways triggering neurodegeneration. Therefore, membrane structure and lipid status should be considered determinant factors in Ab-oligomer-induced synaptic and cell injuries, and therefore AD progression. Numerous epidemiological studies have highlighted close relationships between AD incidence and dietary patterns. Among the nutritional factors involved, lipids significantly influence AD pathogenesis. It is likely that maintenance of adequate membrane lipid content could prevent the production of Ab peptide as well as its deleterious effects upon its interaction with synaptic membrane, thereby protecting neurons from Ab-induced neurodegeneration. As major constituents of neuronal lipids, n-3 polyunsaturated fatty acids are of particular interest in the prevention of AD valuable diet ingredients whose neuroprotective properties could be essential for designing preventive nutritionbased strategies. In this review, we discuss the functional relevance of neuronal membrane features with respect to susceptibility to Ab oligomers and AD pathogenesis, as well as the prospective capacities of lipids to prevent or to delay the disease.

Alzheimer's & Dementia, 2009

No abstract is available. To read the body of this article, please view the Full Text online. ...... more No abstract is available. To read the body of this article, please view the Full Text online. ... © 2009 The Alzheimer's Association. Published by Elsevier Inc. All rights reserved. ... Visit SciVerse ScienceDirect to see if you have access via your institution. ... Advertisements on this site ...

Alzheimer's & Dementia, 2009

Alzheimer's & Dementia, 2009

No abstract is available. To read the body of this article, please view the Full Text online. ...... more No abstract is available. To read the body of this article, please view the Full Text online. ... © 2009 The Alzheimer's Association. Published by Elsevier Inc. All rights reserved. ... Visit SciVerse ScienceDirect to see if you have access via your institution. ... Advertisements on this site ...

Advances in Science and Technology, 2010

... Marcelino Sanchez 1 , Enric Mateu 1 , David Perez 1 , Pierre García 1 , ... Future growth wil... more ... Marcelino Sanchez 1 , Enric Mateu 1 , David Perez 1 , Pierre García 1 , ... Future growth will depend on a successful cost reduction and on a strong effort in R&D to optimize the potential for technical improvement [1]. Testing of new materials, components and systems is still of key ...

The thickness of propellant is an important experimental parameter under T-mode, which has a dire... more The thickness of propellant is an important experimental parameter under T-mode, which has a direct impact on the performance of the laser Micro propulsion. In this paper, the prolusion performance of four propellants with different thickness is measured respectively, the experimental results show that the momentum coupling coefficient Cm rises with the increase of thickness, while the specific impulse Isp

Tonatiuh is an Open Source, Monte-Carlo ray tracer, object-oriented computer program for the desi... more Tonatiuh is an Open Source, Monte-Carlo ray tracer, object-oriented computer program for the design, simulation, and analysis of the optical and energy behavior of solar concentrating systems, which is being developed by the National Renewable Energy Centre of Spain (CENER) in collaboration with the University of Texas at Brownsville (UTB), with the support of the National Renewable Energy Laboratory (NREL). This paper presents the results of a preliminary comparison among Tonatiuh and another state-of-the-art computer code: SolTrace, developed by NREL. These results provide solid evidence that the current release of Tonatiuh does a good job in simulating the optical behavior of single and multi-reflections solar concentrating systems.

This paper presents a validation of DinaCET using experimental data from more than one year opera... more This paper presents a validation of DinaCET using experimental data from more than one year operation of the Nevada Solar One power plant. DinaCET is a computational scheme for the generation of stand-alone dynamic computer programs that simulate the transient behavior of parabolic trough solar thermal power plants. The programs generated by DinaCET are able to simulate a defined power plant, with a given collector field and power block configuration and layout. DinaCET allows the user to define a large range of parameters relevant for detailed simulations, from collector’s geometry and materials to temperature and control system characteristics.

Journal of Neuroscience, 2010

The development of novel therapeutic strategies for Alzheimer&amp... more The development of novel therapeutic strategies for Alzheimer's disease (AD) represents one of the biggest unmet medical needs today. Application of neurotrophic factors able to modulate neuronal survival and synaptic connectivity is a promising therapeutic approach for AD. We aimed to determine whether the loco-regional delivery of ciliary neurotrophic factor (CNTF) could prevent amyloid-beta (Abeta) oligomer-induced synaptic damages and associated cognitive impairments that typify AD. To ensure long-term administration of CNTF in the brain, we used recombinant cells secreting CNTF encapsulated in alginate polymers. The implantation of these bioreactors in the brain of Abeta oligomer-infused mice led to a continuous secretion of recombinant CNTF and was associated with the robust improvement of cognitive performances. Most importantly, CNTF led to full recovery of cognitive functions associated with the stabilization of synaptic protein levels in the Tg2576 AD mouse model. In vitro as well as in vivo, CNTF activated a Janus kinase/signal transducer and activator of transcription-mediated survival pathway that prevented synaptic and neuronal degeneration. These preclinical studies suggest that CNTF and/or CNTF receptor-associated pathways may have AD-modifying activity through protection against progressive Abeta-related memory deficits. Our data also encourage additional exploration of ex vivo gene transfer for the prevention and/or treatment of AD.

Solar Energy, 2012

Abstract This paper analyzes the influence of operational strategies on the performance of parabo... more Abstract This paper analyzes the influence of operational strategies on the performance of parabolic trough (PT) solar power plants with the aid of SimulCET a computer program for the simulation of the energy behavior of PT plants developed by the National Renewable ...

Neurobiology of Aging, 2012

Soluble beta-amyloid (Aβ) oligomers are considered to putatively play a critical role in the earl... more Soluble beta-amyloid (Aβ) oligomers are considered to putatively play a critical role in the early synapse loss and cognitive impairment observed in Alzheimer's disease. We previously demonstrated that Aβ oligomers activate cytosolic phospholipase A(2) (cPLA(2)), which specifically releases arachidonic acid from membrane phospholipids. We here observed that cPLA(2) gene inactivation prevented the alterations of cognitive abilities and the reduction of hippocampal synaptic markers levels noticed upon a single intracerebroventricular injection of Aβ oligomers in wild type mice. We further demonstrated that the Aβ oligomer-induced sphingomyelinase activation was suppressed and that phosphorylation of Akt/protein kinase B (PKB) was preserved in neuronal cells isolated from cPLA(2)(-/-) mice. Interestingly, expression of the Aβ precursor protein (APP) was reduced in hippocampus homogenates and neuronal cells from cPLA(2)(-/-) mice, but the relationship with the resistance of these mice to the Aβ oligomer toxicity requires further investigation. These results therefore show that cPLA(2) plays a key role in the Aβ oligomer-associated neurodegeneration, and as such represents a potential therapeutic target for the treatment of Alzheimer's disease.

Journal of Stroke and Cerebrovascular Diseases, 2013

Background: Frequencies of cognitive impairment and dementia have not been assessed in spontaneou... more Background: Frequencies of cognitive impairment and dementia have not been assessed in spontaneous intracerebral hemorrhage (ICH). The objective of this study was to determine the frequencies and patterns of cognitive impairment and dementia in a cross-sectional study of consecutive patients hospitalized in a single university medical center. Methods: Of 183 consecutive patients hospitalized

Journal of Solar Energy Engineering, 2008

Journal of Neurology, Neurosurgery & Psychiatry, 2006

... User Name. Password. Remember me. Forgot your sign in details? Email Alert Signup. BMJ Career... more ... User Name. Password. Remember me. Forgot your sign in details? Email Alert Signup. BMJ Careers - Latest Neurology and Neurosurgery jobs. Latest neurology and neurosurgery jobs. Show me all Neurology jobs >>. Online ISSN 1468-330X. ...

IEEE Transactions on Nuclear Science, 2000

... Y. Calzavara is with the Valduc CEA Research Center, DRMN/SRNC, 21120 Is sur Tille, France (e... more ... Y. Calzavara is with the Valduc CEA Research Center, DRMN/SRNC, 21120 Is sur Tille, France (e-mail: yoann.calzavara@cea.fr). ... Sci., vol. 43, no. 6, pp. 2742–2750, Dec. 1996. [4] EL Petersen, “Nuclear reactions in semiconductors,” IEEE Trans. Nucl. Sci., vol. 27, no. 6, pp. ...

IEEE Transactions on Nuclear Science, 2000

The possibility to monitor pulsed dose-rate facilities by means of real-time fibered dosimetry is... more The possibility to monitor pulsed dose-rate facilities by means of real-time fibered dosimetry is investigated. A system based on the luminescence of the SrS:Ce,Sm is used to monitor pulses from a medical accelerator with four different dose-rates. The RL signal is characterized using a dedicated acquisition system. The RL recorded is linear with dose-rate and dose. The stem effect due to both Cerenkov emission and photoluminescence in the fiber was also investigated with 18 MV photons and 12 MeV electrons.

IEEE Transactions on Nuclear Science, 2000

A novel real-time optical fibered dosimetry system based on optically stimulated luminescence (OS... more A novel real-time optical fibered dosimetry system based on optically stimulated luminescence (OSL) of SrS:Ce,Sm phosphor was developed and is presented. The advantages of this system are the combination of OSL and optical fibers, immediate readout, simplicity of use, low cost, reliability, flexibility, and robustness. Experimental results show an excellent linearity with the dose (0.01 to 6 Gy), repeatability better than 2%, radiation sensitivity up to 80 mV.cGy -1 and accuracy since error on dose is less than 5%. The applications targeted are the measurement of the dose delivered during a treatment in radiation therapy and the monitoring of the dose or dose-rate around or in nuclear reactor and accelerator facilities in high energy physics. Further experiments are still to be conducted in order to fully characterize the system and evaluate the feasibility of each application mentioned.

IEEE Transactions on Nuclear Science, 2000

The possibility to evaluate simultaneously the total ionizing dose and the displacement damage do... more The possibility to evaluate simultaneously the total ionizing dose and the displacement damage dose using a single OSL integrated sensor is demonstrated. Results obtained during the real time monitoring of both proton and electron beams are presented

Biochimie, 2009

In the absence of efficient diagnostic and therapeutic tools, Alzheimer's disease (AD) is a major... more In the absence of efficient diagnostic and therapeutic tools, Alzheimer's disease (AD) is a major public health concern due to longer life expectancy in the Western countries. Although the precise cause of AD is still unknown, soluble b-amyloid (Ab) oligomers are considered the proximate effectors of the synaptic injury and neuronal death occurring in the early stages of AD. Ab oligomers may directly interact with the synaptic membrane, leading to impairment of synaptic functions and subsequent signalling pathways triggering neurodegeneration. Therefore, membrane structure and lipid status should be considered determinant factors in Ab-oligomer-induced synaptic and cell injuries, and therefore AD progression. Numerous epidemiological studies have highlighted close relationships between AD incidence and dietary patterns. Among the nutritional factors involved, lipids significantly influence AD pathogenesis. It is likely that maintenance of adequate membrane lipid content could prevent the production of Ab peptide as well as its deleterious effects upon its interaction with synaptic membrane, thereby protecting neurons from Ab-induced neurodegeneration. As major constituents of neuronal lipids, n-3 polyunsaturated fatty acids are of particular interest in the prevention of AD valuable diet ingredients whose neuroprotective properties could be essential for designing preventive nutritionbased strategies. In this review, we discuss the functional relevance of neuronal membrane features with respect to susceptibility to Ab oligomers and AD pathogenesis, as well as the prospective capacities of lipids to prevent or to delay the disease.

Alzheimer's & Dementia, 2009

No abstract is available. To read the body of this article, please view the Full Text online. ...... more No abstract is available. To read the body of this article, please view the Full Text online. ... © 2009 The Alzheimer's Association. Published by Elsevier Inc. All rights reserved. ... Visit SciVerse ScienceDirect to see if you have access via your institution. ... Advertisements on this site ...

Alzheimer's & Dementia, 2009

Alzheimer's & Dementia, 2009

No abstract is available. To read the body of this article, please view the Full Text online. ...... more No abstract is available. To read the body of this article, please view the Full Text online. ... © 2009 The Alzheimer's Association. Published by Elsevier Inc. All rights reserved. ... Visit SciVerse ScienceDirect to see if you have access via your institution. ... Advertisements on this site ...

Advances in Science and Technology, 2010

... Marcelino Sanchez 1 , Enric Mateu 1 , David Perez 1 , Pierre García 1 , ... Future growth wil... more ... Marcelino Sanchez 1 , Enric Mateu 1 , David Perez 1 , Pierre García 1 , ... Future growth will depend on a successful cost reduction and on a strong effort in R&D to optimize the potential for technical improvement [1]. Testing of new materials, components and systems is still of key ...

The thickness of propellant is an important experimental parameter under T-mode, which has a dire... more The thickness of propellant is an important experimental parameter under T-mode, which has a direct impact on the performance of the laser Micro propulsion. In this paper, the prolusion performance of four propellants with different thickness is measured respectively, the experimental results show that the momentum coupling coefficient Cm rises with the increase of thickness, while the specific impulse Isp