Sajjad khan - Academia.edu (original) (raw)

Papers by Sajjad khan

The American Journal of Pathology, 2010

Liver damage is a serious clinical complication of ␥-irradiation. We therefore exposed rats to si... more Liver damage is a serious clinical complication of ␥-irradiation. We therefore exposed rats to singledose ␥-irradiation (25 Gy) that was focused on the liver. Three to six hours after irradiation , an increased number of neutrophils (but not mononuclear phagocytes) was observed by immunohistochemistry to be attached to portal vessels between and around the portal (myo)fibroblasts (smooth muscle actin and Thy-1 ؉ cells). MCP-1/CCL2 staining was also detected in the portal vessel walls , including some cells of the portal area. CC-chemokine (MCP-1/CCL2 and MCP-3/CCL7) and CXC-chemokine (KC/CXCL1 , MIP-2/CXCL2 , and LIX/CXCL5) gene expression was significantly induced in total RNA from irradiated livers. In laser capture microdissected samples , an early (1 to 3 hours) up-regulation of CCL2 , CXCL1 , CXCL8, and CXCR2 gene expression was detected in the portal area but not in the parenchyma; with the exception of CXCL1 gene expression. In addition , treatment with an antibody against MCP-1/CCL2 before irradiation led to an increase in gene expression of interferon-␥ and IP-10/CXCL10 in liver tissue without influencing the recruitment of granulocytes. Indeed, the CCL2, CXCL1, CXCL2, and CXCL5 genes were strongly expressed and further up-regulated in liver (myo)fibroblasts after irradiation (8 Gy). Taken together, these results suggest that ␥-irradiation of the liver induces a transient accumulation of granulocytes within the portal area and that (myo)fibroblasts of the portal vessels may be one of the major sources of the chemokines involved in neutrophil recruitment. Moreover, inhibition of more than one chemokine (eg, CXCL1 and CXCL8) may be necessary to reduce leukocytes recruitment.

2002 IEEE MTT-S International Microwave Symposium Digest (Cat. No.02CH37278)

Page 1. TH4D-2 Flexible Beamformer and Remoting Head for Optically Controlled Phased Array Antenn... more Page 1. TH4D-2 Flexible Beamformer and Remoting Head for Optically Controlled Phased Array Antennas Nabeel A. Riza", Sajjad A. Khan, and Muzammil A. Arain Photonic Information Processing Systems (PIPS) Laboratory ...

SPIE Proceedings, 2005

Wavelength tunable and broadband variable fiber-optic attenuators using liquid crystals. [Proceed... more Wavelength tunable and broadband variable fiber-optic attenuators using liquid crystals. [Proceedings of SPIE 5814, 23 (2005)]. Sajjad A. Khan, Nabeel A. Riza. Abstract. Fiber-Optic Variable Optical Attenuators (VOAs) are demonstrated ...

Free-Space Laser Communication and Active Laser Illumination III, 2004

A versatile high speed 3-D scanner design is proposed and demonstrated for optical beamforming ap... more A versatile high speed 3-D scanner design is proposed and demonstrated for optical beamforming applications such as free-space laser communications, 3-D displays, scanning 3-D optical microscopy, data retrieval, and vision applications. The scanner consists of fast digital-analog control polarization-based optical beamforming cells resulting in complete three-dimensional beamforming programmability. Features include low electrical power consumption and large aperture beamforming optics, digital

SPIE Proceedings, 2004

Design and demonstration of a versatile liquid crystal-based scanner is shown for steering a lase... more Design and demonstration of a versatile liquid crystal-based scanner is shown for steering a laser beam in three dimensions. The scanner consists of a unique combination of digital and analog control polarization-based beamforming optics resulting in both continuous and random fashion beam steering. The scanner features a novel device biasing method, large aperture beamforming optics, low electrical power consumption, and ultra-fine as well as wide angle coarse beam steering. Demonstrations include one, two and three dimensional beam steering with a maximum of 40.92 o continuous scan, all at 1550 nm. The minimum scanner aperture is 1 cm diameter and uses a combination of ferroelectric and nematic liquid crystals in addition to Rutile crystal birefringent prisms.

Journal of Lightwave Technology, 2004

A variable fiber-optic delay line (VFODL) is introduced that, to the best of the authors' knowled... more A variable fiber-optic delay line (VFODL) is introduced that, to the best of the authors' knowledge, is the first time that a hybrid analog-digital VFODL is proposed to solve the dilemma of efficiently enabling many settable and long-duration time delays together with continuous and short time delays. In essence, this VFODL can provide near-continuous high-resolution time generation across an entire long-time-delay band. The VFODL is based on the concept of cascaded wavelength-sensitive and wavelength-insensitive time delays. A proof-of-concept VFODL built demonstrates near-continuous 0.5-ps-resolution time-delay control across an entire 25.6-ns time-delay band generating a total of 51 200 measurable time-delay bins. The experimental VFODL also gives a 4.95-dB total optical loss and a 1-ms time-delay control-setting speed. The proposed VFODL can be used in applications such as radio frequency photonic signal processing and radar testing.

Journal of Lightwave Technology, 2007

For the first time, an optimized optical add-drop filter (OADF) for dense wavelength-division-mul... more For the first time, an optimized optical add-drop filter (OADF) for dense wavelength-division-multiplexing systems is demonstrated using the Texas Instruments microelectromechanical-system Digital Micromirror Device (DMD™). This OADF features a polarization-insensitive fault-tolerant broadband operation, low loss, and the ability to selectively add/drop with high-wavelength-resolution multiple channels in the C telecommunications band. The proof-of-concept OADF designed for the C-band demonstrates low insertion loss, 0.15-dB polarization dependent loss, 3-dB wavelength resolution of 0.4 nm, and an average crosstalk of better than 30 dB. With the use of a reference mirror, the OADF becomes a multiwavelength 2 × 2 routing switch.

Enabling Photonics Technologies for Defense, Security, and Aerospace Applications III, 2007

UCC Library and UCC researchers have made this item openly available. Please let us know how this... more UCC Library and UCC researchers have made this item openly available. Please let us know how this has helped you. Thanks! Title Noncontact no-moving parts surface height measurement sensor using liquid crystal-based axial scanning confocal optical microscopy Author(s) Riza, Nabeel A.; Khan, Sajjad A.; Sheikh, Mumtaz A. Publication date 2007-05-23 Original citation Riza, N. A., Khan, S. A. and and Sheikh, M. A. (2007) 'Noncontact nomoving parts surface height measurement sensor using liquid crystalbased axial scanning confocal optical microscopy', Proceddings of SPIE,

The American Journal of Pathology, 2010

Liver damage is a serious clinical complication of ␥-irradiation. We therefore exposed rats to si... more Liver damage is a serious clinical complication of ␥-irradiation. We therefore exposed rats to singledose ␥-irradiation (25 Gy) that was focused on the liver. Three to six hours after irradiation , an increased number of neutrophils (but not mononuclear phagocytes) was observed by immunohistochemistry to be attached to portal vessels between and around the portal (myo)fibroblasts (smooth muscle actin and Thy-1 ؉ cells). MCP-1/CCL2 staining was also detected in the portal vessel walls , including some cells of the portal area. CC-chemokine (MCP-1/CCL2 and MCP-3/CCL7) and CXC-chemokine (KC/CXCL1 , MIP-2/CXCL2 , and LIX/CXCL5) gene expression was significantly induced in total RNA from irradiated livers. In laser capture microdissected samples , an early (1 to 3 hours) up-regulation of CCL2 , CXCL1 , CXCL8, and CXCR2 gene expression was detected in the portal area but not in the parenchyma; with the exception of CXCL1 gene expression. In addition , treatment with an antibody against MCP-1/CCL2 before irradiation led to an increase in gene expression of interferon-␥ and IP-10/CXCL10 in liver tissue without influencing the recruitment of granulocytes. Indeed, the CCL2, CXCL1, CXCL2, and CXCL5 genes were strongly expressed and further up-regulated in liver (myo)fibroblasts after irradiation (8 Gy). Taken together, these results suggest that ␥-irradiation of the liver induces a transient accumulation of granulocytes within the portal area and that (myo)fibroblasts of the portal vessels may be one of the major sources of the chemokines involved in neutrophil recruitment. Moreover, inhibition of more than one chemokine (eg, CXCL1 and CXCL8) may be necessary to reduce leukocytes recruitment.

2002 IEEE MTT-S International Microwave Symposium Digest (Cat. No.02CH37278)

Page 1. TH4D-2 Flexible Beamformer and Remoting Head for Optically Controlled Phased Array Antenn... more Page 1. TH4D-2 Flexible Beamformer and Remoting Head for Optically Controlled Phased Array Antennas Nabeel A. Riza", Sajjad A. Khan, and Muzammil A. Arain Photonic Information Processing Systems (PIPS) Laboratory ...

SPIE Proceedings, 2005

Wavelength tunable and broadband variable fiber-optic attenuators using liquid crystals. [Proceed... more Wavelength tunable and broadband variable fiber-optic attenuators using liquid crystals. [Proceedings of SPIE 5814, 23 (2005)]. Sajjad A. Khan, Nabeel A. Riza. Abstract. Fiber-Optic Variable Optical Attenuators (VOAs) are demonstrated ...

Free-Space Laser Communication and Active Laser Illumination III, 2004

A versatile high speed 3-D scanner design is proposed and demonstrated for optical beamforming ap... more A versatile high speed 3-D scanner design is proposed and demonstrated for optical beamforming applications such as free-space laser communications, 3-D displays, scanning 3-D optical microscopy, data retrieval, and vision applications. The scanner consists of fast digital-analog control polarization-based optical beamforming cells resulting in complete three-dimensional beamforming programmability. Features include low electrical power consumption and large aperture beamforming optics, digital

SPIE Proceedings, 2004

Design and demonstration of a versatile liquid crystal-based scanner is shown for steering a lase... more Design and demonstration of a versatile liquid crystal-based scanner is shown for steering a laser beam in three dimensions. The scanner consists of a unique combination of digital and analog control polarization-based beamforming optics resulting in both continuous and random fashion beam steering. The scanner features a novel device biasing method, large aperture beamforming optics, low electrical power consumption, and ultra-fine as well as wide angle coarse beam steering. Demonstrations include one, two and three dimensional beam steering with a maximum of 40.92 o continuous scan, all at 1550 nm. The minimum scanner aperture is 1 cm diameter and uses a combination of ferroelectric and nematic liquid crystals in addition to Rutile crystal birefringent prisms.

Journal of Lightwave Technology, 2004

A variable fiber-optic delay line (VFODL) is introduced that, to the best of the authors' knowled... more A variable fiber-optic delay line (VFODL) is introduced that, to the best of the authors' knowledge, is the first time that a hybrid analog-digital VFODL is proposed to solve the dilemma of efficiently enabling many settable and long-duration time delays together with continuous and short time delays. In essence, this VFODL can provide near-continuous high-resolution time generation across an entire long-time-delay band. The VFODL is based on the concept of cascaded wavelength-sensitive and wavelength-insensitive time delays. A proof-of-concept VFODL built demonstrates near-continuous 0.5-ps-resolution time-delay control across an entire 25.6-ns time-delay band generating a total of 51 200 measurable time-delay bins. The experimental VFODL also gives a 4.95-dB total optical loss and a 1-ms time-delay control-setting speed. The proposed VFODL can be used in applications such as radio frequency photonic signal processing and radar testing.

Journal of Lightwave Technology, 2007

For the first time, an optimized optical add-drop filter (OADF) for dense wavelength-division-mul... more For the first time, an optimized optical add-drop filter (OADF) for dense wavelength-division-multiplexing systems is demonstrated using the Texas Instruments microelectromechanical-system Digital Micromirror Device (DMD™). This OADF features a polarization-insensitive fault-tolerant broadband operation, low loss, and the ability to selectively add/drop with high-wavelength-resolution multiple channels in the C telecommunications band. The proof-of-concept OADF designed for the C-band demonstrates low insertion loss, 0.15-dB polarization dependent loss, 3-dB wavelength resolution of 0.4 nm, and an average crosstalk of better than 30 dB. With the use of a reference mirror, the OADF becomes a multiwavelength 2 × 2 routing switch.

Enabling Photonics Technologies for Defense, Security, and Aerospace Applications III, 2007

UCC Library and UCC researchers have made this item openly available. Please let us know how this... more UCC Library and UCC researchers have made this item openly available. Please let us know how this has helped you. Thanks! Title Noncontact no-moving parts surface height measurement sensor using liquid crystal-based axial scanning confocal optical microscopy Author(s) Riza, Nabeel A.; Khan, Sajjad A.; Sheikh, Mumtaz A. Publication date 2007-05-23 Original citation Riza, N. A., Khan, S. A. and and Sheikh, M. A. (2007) 'Noncontact nomoving parts surface height measurement sensor using liquid crystalbased axial scanning confocal optical microscopy', Proceddings of SPIE,