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Minh Quân Vũ

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Tanta University

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Botswana International University of Science & Technology

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University of Toronto

Praxis Business School

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Papers by Minh Quân Vũ

Toward Practical Entanglement-Based Satellite FSO/QKD Systems Using Dual-Threshold/ Direct Detection

IEEE Access

We propose a new implementation of the BBM92 protocol for satellite continuous-variable quantum k... more We propose a new implementation of the BBM92 protocol for satellite continuous-variable quantum key distribution (CV-QKD) systems using the dual-threshold/direct detection (DT/DD) scheme. The proposed system is less complex and therefore possibly cheaper than current discrete-variable (DV) and CV-QKD ones using coherent detection receivers. We model and analyze the performance of the proposed system in the context that a satellite distributes secret keys to two legitimate users. The analytical results are derived by considering channel loss, atmospheric turbulence-induced fading, and receiver noises. The Gaussian beam model is considered to evaluate the impact of geometric spread on the signal received by legitimate users and the possibility of being eavesdropped. Based on the design criteria for the system and analytical results, we investigate the feasibility of a case study for the Japan QKD network using the existing low-Earth orbit (LEO) satellite constellation.

Performance Enhancement of HAP-Based Relaying M-PPM FSO System Using Spatial Diversity and Heterodyne Detection Receiver

Journal of Optical Communications, 2018

In this paper, we investigate the performance of a high-altitude platform (HAP)-based relaying fr... more In this paper, we investigate the performance of a high-altitude platform (HAP)-based relaying free-space optical communication (FSO) system, where HAP plays a role as a relay node that employs detect-and-forward relaying scheme to connect between two ground stations (GSs). M $M$ -ary pulse-position modulation (PPM), spatial diversity, and heterodyne detection receiver are used to improve the system’s performance. Instead of using multiple-input multiple-output (MIMO), which makes the HAP complex, multiple-input single-output (MISO) is applied to the uplink while single-input multiple-output (SIMO) is utilized for the downlink. Consequently, the HAP only needs a couple of transmit and receive aperture. The expression for the bit error rate (BER) of the proposed FSO system is derived considering the impact of atmospheric attenuation and turbulence. The achievable BER with low values has proved the feasibility of our proposed system. In addition, the advantages of using M $M$ -PPM, sp...

Analysis of middle ear morphology for design of a transnasal endoscope

Cholesteatomas are benign lesions that form in the middle ear (ME). They can cause debilitating s... more Cholesteatomas are benign lesions that form in the middle ear (ME). They can cause debilitating side effects including hearing loss, recurrent ear infection and drainage, and balance disruption. The current approach for positively identifying cholesteatomas requires intraoperative visualization either by lifting the ear drum or transmitting an endoscope through the ear canal and tympanic membrane – procedures which are typically done in and operating room with the patient under general anesthesia. We are developing a novel endoscope that can be inserted trans-nasally and could potentially be used in an outpatient setting allowing clinicians to easily detect and visualize cholesteatomas and other middle ear conditions. A crucial part of designing this device is determining the degrees of freedom necessary to visualize the regions of interest in the middle ear space. To permit virtual evaluation of scope design, in this work we propose to create a library of models of the most difficu...

Electronic measurement of off-center run-out and reel-hub mismatch

Adaptive impedance control of a haptic teleoperation system for improved transparency

2012 IEEE International Workshop on Haptic Audio Visual Environments and Games (HAVE 2012) Proceedings, 2012

ABSTRACT An adaptive impedance force control model of a haptic device for teleoperation is analyz... more ABSTRACT An adaptive impedance force control model of a haptic device for teleoperation is analyzed. A new force control model of the haptic device is constructed to investigate the dynamic effects of the user hand. Movements of the user hand may work as a force disturbance to the haptic force control system so that it is difficult to realize a good transparency. A model reference adaptive control (MRAC) is proposed to improve the transparency of the haptic device. A third order reference model with relative degree one is selected to satisfy requirements of rise time, settling time and overshoots. Experiments show that the force tracking performances are improved while force disturbances from the user hand are well compensated.

Viral molecular characterization of the first congenital rubella syndrome case in Vietnam

Clinical laboratory, 2011

Rubella virus (RV) infection during the first trimester of pregnancy often leads to severe birth ... more Rubella virus (RV) infection during the first trimester of pregnancy often leads to severe birth defects known as congenital rubella syndrome (CRS). A premature newborn male was clinically diagnosed as CRS with cataracts, congenital heart defects, microcephaly, hepatosplenomegaly, and thrombocytopenia. The infection was confirmed serologically and molecularly. The RV was characterized and clustered with the 2B genotype. The integrated description of clinical features, serological and molecular data provide a baseline for diagnosis and control of rubella and CRS in Vietnam. This is the first report of molecular investigation of wildtype RV strain in Vietnam, thus contributing to the documentation of RV's worldwide distribution.

Scaffold hopping towards potent and selective JAK3 inhibitors: discovery of novel C-5 substituted pyrrolopyrazines

Bioorganic & medicinal chemistry letters, 2014

The discovery of a novel series of pyrrolopyrazines as JAK inhibitors with comparable enzyme and ... more The discovery of a novel series of pyrrolopyrazines as JAK inhibitors with comparable enzyme and cellular activity to tofacitinib is described. The series was identified using a scaffold hopping approach aided by structure based drug design using principles of intramolecular hydrogen bonding for conformational restriction and targeting specific pockets for modulating kinase activity.

E2 agent plugin architecture

International Conference on Integration of Knowledge Intensive Multi-Agent Systems, 2005.

E2 is a plugin-based, service-oriented middleware architecture. E2 extends the popular Eclipse pl... more E2 is a plugin-based, service-oriented middleware architecture. E2 extends the popular Eclipse platform's idea of building a software system entirely and dynamically from XML-interfaced plugins, adds the feature to remove and replace plugins on the fly, administers the plugin connection process, and provides a message transport plugin for distributed inter-E2 system communication. E2 introduces a generic user interface plugin that separates user interfaces and application functionality. With these extensions, E2 extends the plugin concept, with its success on the desktop, to the broader areas of distributed middleware and multi-agent systems. E2 retains compatibility with Eclipse so that it can reuse Eclipse plugins but also, via an extensible interpreter capability, adds compatibility with Web Services and WSDL. This paper describes the E2 platform, implemented in Java, being used to develop the Everything is Alive agent system.

Email user ranking based on email networks

AIP Conference Proceedings, 2012

In this paper, four spam-filtering approaches based on the mail networks: Clustering, Extended Cl... more In this paper, four spam-filtering approaches based on the mail networks: Clustering, Extended Clustering Coefficient, PageRank Algorithm and Weighted PageRank Algorithm are analyzed. We also propose a couple of fully worked-out datasets against which the experimental comparisons with the respect to the accuracy of email user ranking and spam filtering are conducted. The results indicate that PageRank algorithm and Extended Clustering Coefficient approaches are better than others. The rate of true detection is over 99.5% while the failed alarm remains below 0.5%.

Restoration of fertility in oophorectomized rats after tubo‐ovarian transplantation

Microsurgery, 2002

Improved microsurgical techniques for en bloc vascularized adnexal isograft in the rat is describ... more Improved microsurgical techniques for en bloc vascularized adnexal isograft in the rat is described. The graft of the right ovary together with its fallopian tube and upper third of uterus was transplanted orthotopically with end‐to‐side anastomoses between the donor aortic segment and recipient aorta and between the donor vena cava segment and recipient inferior vena cava, with end‐to‐end anastomosis of the donor and recipient uterus in a syngeneic, bilaterally oophorectomized rat. All transplantations were successful in terms of immediate vascular patency rate (10/10, 100%). Evidence of resumed ovarian function was obtained in 9 out of 10 rats (9/10, 90.0%) by histological demonstration of the vaginal smear, in which pregnancies were achieved in six rats (6/10, 60.0%) and six litters of healthy offspring were delivered 9 weeks later after transplantation. These results suggest that microsurgical ovarian transplantation provide a new and potential experimental model for the study o...

Synergistic effect of vincristine with tacrolimus or sirolimus in prevention of acute heart allograft rejection in the rat

Microsurgery, 2003

The application of multiple immunosuppressive therapy for organ transplantation could enhance the... more The application of multiple immunosuppressive therapy for organ transplantation could enhance therapeutic efficacy, while minimizing the toxicity of individual drugs used in the regimen. In this study, the effect of the combined therapy of vincristine (VCR) with tacrolimus (FK506) or sirolimus (rapamycin, RAPA) was tested in prevention of acute heart allograft rejection in the rat. A Brown Norway (BN, RT 1n) to Lewis (LEW, RT 11) rat combination was used in a heart allografting model. VCR was administered intraperitoneally once daily, while FK506 and RAPA were given by gavage once daily for 14 days after transplantation. There were dose‐related prolongations of mean survival time (MST) to monotherapy of VCR, FK506, or RAPA. The MST in combination therapy indicated that a synergistic interaction was produced when compared with the respective monotherapies: VCR 0.05 mg/kg/day + FK506 0.5 mg/kg/day (16.00 ± 1.79 days, P = 0.001; combination index (CI) = 0.557); VCR 0.05 mg/kg/day + FK5...

Different Costimulatory and Growth Factor Requirements for CD4+ and CD8+ T Cell-Mediated Rejection

The Journal of Immunology, 2004

Costimulatory signals and growth factor signals play a key role in commanding T cell activation a... more Costimulatory signals and growth factor signals play a key role in commanding T cell activation and T cell effector function. However, how costimulatory signals and growth factor signals interact and integrate into the activation program of CD4+ and CD8+ T cells during the allograft response remains poorly defined. In the present study we found that either CD4- or CD8-deficient mice can vigorously reject the skin allografts. Blocking rapamycin-sensitive growth factor signals produced long term skin allograft survival in CD4-deficient mice (mean survival time, >120 days), but not in CD8-deficient mice (mean survival time, 20 days). Analysis of CFSE-labeled cells proliferating in the allogeneic hosts revealed that clonal expansion of CD4+ T cells in vivo was more resistant to growth factor blockade than that of CD8+ T cells. However, blockade or genetic absence of CD28/CD154 costimulatory molecules rendered CD4+ T cell-mediated rejection sensitive to rapamycin, and long term skin a...

Critical, but Conditional, Role of OX40 in Memory T Cell-Mediated Rejection

The Journal of Immunology, 2006

Memory T cells can be a significant barrier to the induction of transplant tolerance. However, th... more Memory T cells can be a significant barrier to the induction of transplant tolerance. However, the molecular pathways that can regulate memory T cell-mediated rejection are poorly defined. In the present study we tested the hypothesis that the novel alternative costimulatory molecules (i.e., ICOS, 4-1BB, OX40, or CD30) may play a critical role in memory T cell activation and memory T cell-mediated rejection. We found that memory T cells, generated by either homeostatic proliferation or donor Ag priming, induced prompt skin allograft rejection regardless of CD28/CD154 blockade. Phenotypic analysis showed that, in contrast to naive T cells, such memory T cells expressed high levels of OX40, 4-1BB, and ICOS on the cell surface. In a skin transplant model in which rejection was mediated by memory T cells, blocking the OX40/OX40 ligand pathway alone did not prolong the skin allograft survival, but blocking OX40 costimulation in combination with CD28/CD154 blockade induced long-term skin ...

OX40 Controls Functionally Different T Cell Subsets and Their Resistance to Depletion Therapy

The Journal of Immunology, 2007

T cell depletion is a widely used approach in clinical transplantation. However, not all T cells ... more T cell depletion is a widely used approach in clinical transplantation. However, not all T cells are equally sensitive to depletion therapies and a significant fraction of T cells persists even after aggressive treatment. The functional attributes of such T cells and the mechanisms responsible for their resistance to depletion are poorly studied. In the present study, we showed that CD4+ T cells that are resistant to polyclonal anti-lymphocyte serum (ALS) mediated depletion exhibit phenotypic features of memory cells and uniformly express OX40 on the cell surface. Studies using the foxp3gfp knockin mice revealed that the remaining CD4+OX40+ cells consist of Foxp3+ Tregs and Foxp3− T effector/memory cells. The ALS-resistant CD4+OX40+ cells failed to mediate skin allograft rejection upon adoptive transferring into congenic Rag−/− mice, but removal of Foxp3+ Tregs from the OX40+ cells resulted in prompt skin allograft rejection. Importantly, OX40 is critical to survival of both Foxp3+ ...

NK cells promote transplant tolerance by killing donor antigen-presenting cells

The Journal of Experimental Medicine, 2006

Natural killer (NK) cells are programmed to kill target cells without prior antigen priming. Beca... more Natural killer (NK) cells are programmed to kill target cells without prior antigen priming. Because of their potent cytolytic activities, NK cells are one of the key cell types involved in dismantling allografts. However, in certain transplant models, NK cells also express potent immunoregulatory properties that promote tolerance induction. The precise mechanism for such striking dichotomy remains unknown. In the present study, we showed in a skin transplant model that the skin allografts contain a subset of antigen-presenting cells (APCs) that can home to the recipient mice. We also showed that such graft-derived APCs are usually destroyed by the host NK cells. But in the absence of NK cells, donor APCs can survive and then migrate to the host lymphoid and extralymphoid sites where they directly stimulate the activation of alloreactive T cells. T cells activated in the absence of NK cells are more resistant to costimulatory blockade treatment, and under such conditions stable skin...

Artificial neural network for tsunami forecasting

Journal of Asian Earth Sciences, 2009

This paper presents a data-driven approach for effective and efficient forecasting of tsunami gen... more

A New 6-DOF Haptic Device for Teleoperation of 6-DOF Serial Robots

IEEE Transactions on Instrumentation and Measurement, 2011

Use of nurse-observed symptoms of delirium in long-term care: effects on prevalence and outcomes of delirium

International psychogeriatrics / IPA, 2011

Previous studies have reported that nurse detection of delirium has low sensitivity compared to a... more Previous studies have reported that nurse detection of delirium has low sensitivity compared to a research diagnosis. As yet, no study has examined the use of nurse-observed delirium symptoms combined with research-observed delirium symptoms to diagnose delirium. Our specific aims were: (1) to describe the effect of using nurse-observed symptoms on the prevalence of delirium symptoms and diagnoses in long-term care (LTC) facilities, and (2) to compare the predictive validity of delirium diagnoses based on the use of research-observed symptoms alone with those based on research-observed and nurse-observed symptoms.

Prevalence and incidence of delirium in long-term care

International journal of geriatric psychiatry, 2011

OBJECTIVES: (1) To describe the prevalence and 6-month incidence of delirium in long-term care fa... more OBJECTIVES: (1) To describe the prevalence and 6-month incidence of delirium in long-term care facility (LTCF) residents age 65 and over; (2) To describe differences in these measures by resident baseline characteristics. METHODS: A multisite, prospective observational study was conducted in seven LTCFs in the province of Quebec, Canada. Residents of age 65 and over were recruited into two cohorts: Cohort A with a Mini-Mental State Examination (MMSE) score of 10 or more and Cohort B with an MMSE score of less than 10. Baseline resident measurements were obtained from research resident assessments, nurse interviews, and chart review. Weekly resident assessments for up to 24 weeks included the Confusion Assessment Method (CAM). RESULTS: Two hundred seventy-nine residents were recruited and completed baseline delirium assessments: 204 in Cohort A and 75 in Cohort B. The prevalence of delirium at baseline was 3.4% in Cohort A and 33.3% in Cohort B. The incidence of delirium among those ...

Subsyndromal delirium in older long-term care residents: incidence, risk factors, and outcomes

Journal of the American Geriatrics Society, 2011

To determine the incidence of, risk factors for, and outcomes of subsyndromal delirium (SSD) in o... more

Toward Practical Entanglement-Based Satellite FSO/QKD Systems Using Dual-Threshold/ Direct Detection

IEEE Access

We propose a new implementation of the BBM92 protocol for satellite continuous-variable quantum k... more We propose a new implementation of the BBM92 protocol for satellite continuous-variable quantum key distribution (CV-QKD) systems using the dual-threshold/direct detection (DT/DD) scheme. The proposed system is less complex and therefore possibly cheaper than current discrete-variable (DV) and CV-QKD ones using coherent detection receivers. We model and analyze the performance of the proposed system in the context that a satellite distributes secret keys to two legitimate users. The analytical results are derived by considering channel loss, atmospheric turbulence-induced fading, and receiver noises. The Gaussian beam model is considered to evaluate the impact of geometric spread on the signal received by legitimate users and the possibility of being eavesdropped. Based on the design criteria for the system and analytical results, we investigate the feasibility of a case study for the Japan QKD network using the existing low-Earth orbit (LEO) satellite constellation.

Performance Enhancement of HAP-Based Relaying M-PPM FSO System Using Spatial Diversity and Heterodyne Detection Receiver

Journal of Optical Communications, 2018

In this paper, we investigate the performance of a high-altitude platform (HAP)-based relaying fr... more In this paper, we investigate the performance of a high-altitude platform (HAP)-based relaying free-space optical communication (FSO) system, where HAP plays a role as a relay node that employs detect-and-forward relaying scheme to connect between two ground stations (GSs). M $M$ -ary pulse-position modulation (PPM), spatial diversity, and heterodyne detection receiver are used to improve the system’s performance. Instead of using multiple-input multiple-output (MIMO), which makes the HAP complex, multiple-input single-output (MISO) is applied to the uplink while single-input multiple-output (SIMO) is utilized for the downlink. Consequently, the HAP only needs a couple of transmit and receive aperture. The expression for the bit error rate (BER) of the proposed FSO system is derived considering the impact of atmospheric attenuation and turbulence. The achievable BER with low values has proved the feasibility of our proposed system. In addition, the advantages of using M $M$ -PPM, sp...

Analysis of middle ear morphology for design of a transnasal endoscope

Cholesteatomas are benign lesions that form in the middle ear (ME). They can cause debilitating s... more Cholesteatomas are benign lesions that form in the middle ear (ME). They can cause debilitating side effects including hearing loss, recurrent ear infection and drainage, and balance disruption. The current approach for positively identifying cholesteatomas requires intraoperative visualization either by lifting the ear drum or transmitting an endoscope through the ear canal and tympanic membrane – procedures which are typically done in and operating room with the patient under general anesthesia. We are developing a novel endoscope that can be inserted trans-nasally and could potentially be used in an outpatient setting allowing clinicians to easily detect and visualize cholesteatomas and other middle ear conditions. A crucial part of designing this device is determining the degrees of freedom necessary to visualize the regions of interest in the middle ear space. To permit virtual evaluation of scope design, in this work we propose to create a library of models of the most difficu...

Electronic measurement of off-center run-out and reel-hub mismatch

Adaptive impedance control of a haptic teleoperation system for improved transparency

2012 IEEE International Workshop on Haptic Audio Visual Environments and Games (HAVE 2012) Proceedings, 2012

ABSTRACT An adaptive impedance force control model of a haptic device for teleoperation is analyz... more ABSTRACT An adaptive impedance force control model of a haptic device for teleoperation is analyzed. A new force control model of the haptic device is constructed to investigate the dynamic effects of the user hand. Movements of the user hand may work as a force disturbance to the haptic force control system so that it is difficult to realize a good transparency. A model reference adaptive control (MRAC) is proposed to improve the transparency of the haptic device. A third order reference model with relative degree one is selected to satisfy requirements of rise time, settling time and overshoots. Experiments show that the force tracking performances are improved while force disturbances from the user hand are well compensated.

Viral molecular characterization of the first congenital rubella syndrome case in Vietnam

Clinical laboratory, 2011

Rubella virus (RV) infection during the first trimester of pregnancy often leads to severe birth ... more Rubella virus (RV) infection during the first trimester of pregnancy often leads to severe birth defects known as congenital rubella syndrome (CRS). A premature newborn male was clinically diagnosed as CRS with cataracts, congenital heart defects, microcephaly, hepatosplenomegaly, and thrombocytopenia. The infection was confirmed serologically and molecularly. The RV was characterized and clustered with the 2B genotype. The integrated description of clinical features, serological and molecular data provide a baseline for diagnosis and control of rubella and CRS in Vietnam. This is the first report of molecular investigation of wildtype RV strain in Vietnam, thus contributing to the documentation of RV's worldwide distribution.

Scaffold hopping towards potent and selective JAK3 inhibitors: discovery of novel C-5 substituted pyrrolopyrazines

Bioorganic & medicinal chemistry letters, 2014

The discovery of a novel series of pyrrolopyrazines as JAK inhibitors with comparable enzyme and ... more The discovery of a novel series of pyrrolopyrazines as JAK inhibitors with comparable enzyme and cellular activity to tofacitinib is described. The series was identified using a scaffold hopping approach aided by structure based drug design using principles of intramolecular hydrogen bonding for conformational restriction and targeting specific pockets for modulating kinase activity.

E2 agent plugin architecture

International Conference on Integration of Knowledge Intensive Multi-Agent Systems, 2005.

E2 is a plugin-based, service-oriented middleware architecture. E2 extends the popular Eclipse pl... more E2 is a plugin-based, service-oriented middleware architecture. E2 extends the popular Eclipse platform's idea of building a software system entirely and dynamically from XML-interfaced plugins, adds the feature to remove and replace plugins on the fly, administers the plugin connection process, and provides a message transport plugin for distributed inter-E2 system communication. E2 introduces a generic user interface plugin that separates user interfaces and application functionality. With these extensions, E2 extends the plugin concept, with its success on the desktop, to the broader areas of distributed middleware and multi-agent systems. E2 retains compatibility with Eclipse so that it can reuse Eclipse plugins but also, via an extensible interpreter capability, adds compatibility with Web Services and WSDL. This paper describes the E2 platform, implemented in Java, being used to develop the Everything is Alive agent system.

Email user ranking based on email networks

AIP Conference Proceedings, 2012

In this paper, four spam-filtering approaches based on the mail networks: Clustering, Extended Cl... more In this paper, four spam-filtering approaches based on the mail networks: Clustering, Extended Clustering Coefficient, PageRank Algorithm and Weighted PageRank Algorithm are analyzed. We also propose a couple of fully worked-out datasets against which the experimental comparisons with the respect to the accuracy of email user ranking and spam filtering are conducted. The results indicate that PageRank algorithm and Extended Clustering Coefficient approaches are better than others. The rate of true detection is over 99.5% while the failed alarm remains below 0.5%.

Restoration of fertility in oophorectomized rats after tubo‐ovarian transplantation

Microsurgery, 2002

Improved microsurgical techniques for en bloc vascularized adnexal isograft in the rat is describ... more Improved microsurgical techniques for en bloc vascularized adnexal isograft in the rat is described. The graft of the right ovary together with its fallopian tube and upper third of uterus was transplanted orthotopically with end‐to‐side anastomoses between the donor aortic segment and recipient aorta and between the donor vena cava segment and recipient inferior vena cava, with end‐to‐end anastomosis of the donor and recipient uterus in a syngeneic, bilaterally oophorectomized rat. All transplantations were successful in terms of immediate vascular patency rate (10/10, 100%). Evidence of resumed ovarian function was obtained in 9 out of 10 rats (9/10, 90.0%) by histological demonstration of the vaginal smear, in which pregnancies were achieved in six rats (6/10, 60.0%) and six litters of healthy offspring were delivered 9 weeks later after transplantation. These results suggest that microsurgical ovarian transplantation provide a new and potential experimental model for the study o...

Synergistic effect of vincristine with tacrolimus or sirolimus in prevention of acute heart allograft rejection in the rat

Microsurgery, 2003

The application of multiple immunosuppressive therapy for organ transplantation could enhance the... more The application of multiple immunosuppressive therapy for organ transplantation could enhance therapeutic efficacy, while minimizing the toxicity of individual drugs used in the regimen. In this study, the effect of the combined therapy of vincristine (VCR) with tacrolimus (FK506) or sirolimus (rapamycin, RAPA) was tested in prevention of acute heart allograft rejection in the rat. A Brown Norway (BN, RT 1n) to Lewis (LEW, RT 11) rat combination was used in a heart allografting model. VCR was administered intraperitoneally once daily, while FK506 and RAPA were given by gavage once daily for 14 days after transplantation. There were dose‐related prolongations of mean survival time (MST) to monotherapy of VCR, FK506, or RAPA. The MST in combination therapy indicated that a synergistic interaction was produced when compared with the respective monotherapies: VCR 0.05 mg/kg/day + FK506 0.5 mg/kg/day (16.00 ± 1.79 days, P = 0.001; combination index (CI) = 0.557); VCR 0.05 mg/kg/day + FK5...

Different Costimulatory and Growth Factor Requirements for CD4+ and CD8+ T Cell-Mediated Rejection

The Journal of Immunology, 2004

Costimulatory signals and growth factor signals play a key role in commanding T cell activation a... more Costimulatory signals and growth factor signals play a key role in commanding T cell activation and T cell effector function. However, how costimulatory signals and growth factor signals interact and integrate into the activation program of CD4+ and CD8+ T cells during the allograft response remains poorly defined. In the present study we found that either CD4- or CD8-deficient mice can vigorously reject the skin allografts. Blocking rapamycin-sensitive growth factor signals produced long term skin allograft survival in CD4-deficient mice (mean survival time, >120 days), but not in CD8-deficient mice (mean survival time, 20 days). Analysis of CFSE-labeled cells proliferating in the allogeneic hosts revealed that clonal expansion of CD4+ T cells in vivo was more resistant to growth factor blockade than that of CD8+ T cells. However, blockade or genetic absence of CD28/CD154 costimulatory molecules rendered CD4+ T cell-mediated rejection sensitive to rapamycin, and long term skin a...

Critical, but Conditional, Role of OX40 in Memory T Cell-Mediated Rejection

The Journal of Immunology, 2006

Memory T cells can be a significant barrier to the induction of transplant tolerance. However, th... more Memory T cells can be a significant barrier to the induction of transplant tolerance. However, the molecular pathways that can regulate memory T cell-mediated rejection are poorly defined. In the present study we tested the hypothesis that the novel alternative costimulatory molecules (i.e., ICOS, 4-1BB, OX40, or CD30) may play a critical role in memory T cell activation and memory T cell-mediated rejection. We found that memory T cells, generated by either homeostatic proliferation or donor Ag priming, induced prompt skin allograft rejection regardless of CD28/CD154 blockade. Phenotypic analysis showed that, in contrast to naive T cells, such memory T cells expressed high levels of OX40, 4-1BB, and ICOS on the cell surface. In a skin transplant model in which rejection was mediated by memory T cells, blocking the OX40/OX40 ligand pathway alone did not prolong the skin allograft survival, but blocking OX40 costimulation in combination with CD28/CD154 blockade induced long-term skin ...

OX40 Controls Functionally Different T Cell Subsets and Their Resistance to Depletion Therapy

The Journal of Immunology, 2007

T cell depletion is a widely used approach in clinical transplantation. However, not all T cells ... more T cell depletion is a widely used approach in clinical transplantation. However, not all T cells are equally sensitive to depletion therapies and a significant fraction of T cells persists even after aggressive treatment. The functional attributes of such T cells and the mechanisms responsible for their resistance to depletion are poorly studied. In the present study, we showed that CD4+ T cells that are resistant to polyclonal anti-lymphocyte serum (ALS) mediated depletion exhibit phenotypic features of memory cells and uniformly express OX40 on the cell surface. Studies using the foxp3gfp knockin mice revealed that the remaining CD4+OX40+ cells consist of Foxp3+ Tregs and Foxp3− T effector/memory cells. The ALS-resistant CD4+OX40+ cells failed to mediate skin allograft rejection upon adoptive transferring into congenic Rag−/− mice, but removal of Foxp3+ Tregs from the OX40+ cells resulted in prompt skin allograft rejection. Importantly, OX40 is critical to survival of both Foxp3+ ...

NK cells promote transplant tolerance by killing donor antigen-presenting cells

The Journal of Experimental Medicine, 2006

Natural killer (NK) cells are programmed to kill target cells without prior antigen priming. Beca... more Natural killer (NK) cells are programmed to kill target cells without prior antigen priming. Because of their potent cytolytic activities, NK cells are one of the key cell types involved in dismantling allografts. However, in certain transplant models, NK cells also express potent immunoregulatory properties that promote tolerance induction. The precise mechanism for such striking dichotomy remains unknown. In the present study, we showed in a skin transplant model that the skin allografts contain a subset of antigen-presenting cells (APCs) that can home to the recipient mice. We also showed that such graft-derived APCs are usually destroyed by the host NK cells. But in the absence of NK cells, donor APCs can survive and then migrate to the host lymphoid and extralymphoid sites where they directly stimulate the activation of alloreactive T cells. T cells activated in the absence of NK cells are more resistant to costimulatory blockade treatment, and under such conditions stable skin...

Artificial neural network for tsunami forecasting

Journal of Asian Earth Sciences, 2009

This paper presents a data-driven approach for effective and efficient forecasting of tsunami gen... more

A New 6-DOF Haptic Device for Teleoperation of 6-DOF Serial Robots

IEEE Transactions on Instrumentation and Measurement, 2011

Use of nurse-observed symptoms of delirium in long-term care: effects on prevalence and outcomes of delirium

International psychogeriatrics / IPA, 2011

Previous studies have reported that nurse detection of delirium has low sensitivity compared to a... more Previous studies have reported that nurse detection of delirium has low sensitivity compared to a research diagnosis. As yet, no study has examined the use of nurse-observed delirium symptoms combined with research-observed delirium symptoms to diagnose delirium. Our specific aims were: (1) to describe the effect of using nurse-observed symptoms on the prevalence of delirium symptoms and diagnoses in long-term care (LTC) facilities, and (2) to compare the predictive validity of delirium diagnoses based on the use of research-observed symptoms alone with those based on research-observed and nurse-observed symptoms.

Prevalence and incidence of delirium in long-term care

International journal of geriatric psychiatry, 2011

OBJECTIVES: (1) To describe the prevalence and 6-month incidence of delirium in long-term care fa... more OBJECTIVES: (1) To describe the prevalence and 6-month incidence of delirium in long-term care facility (LTCF) residents age 65 and over; (2) To describe differences in these measures by resident baseline characteristics. METHODS: A multisite, prospective observational study was conducted in seven LTCFs in the province of Quebec, Canada. Residents of age 65 and over were recruited into two cohorts: Cohort A with a Mini-Mental State Examination (MMSE) score of 10 or more and Cohort B with an MMSE score of less than 10. Baseline resident measurements were obtained from research resident assessments, nurse interviews, and chart review. Weekly resident assessments for up to 24 weeks included the Confusion Assessment Method (CAM). RESULTS: Two hundred seventy-nine residents were recruited and completed baseline delirium assessments: 204 in Cohort A and 75 in Cohort B. The prevalence of delirium at baseline was 3.4% in Cohort A and 33.3% in Cohort B. The incidence of delirium among those ...

Subsyndromal delirium in older long-term care residents: incidence, risk factors, and outcomes

Journal of the American Geriatrics Society, 2011

To determine the incidence of, risk factors for, and outcomes of subsyndromal delirium (SSD) in o... more