Hsr Mohamed - Academia.edu (original) (raw)

Papers by Hsr Mohamed

Metallurgical and Materials Transactions A-physical Metallurgy and Materials Science, 2006

The ductility and creep of bulk ultra-fine-grained (UFG) 5083 Al (grain size ∼440 nm) processed b... more The ductility and creep of bulk ultra-fine-grained (UFG) 5083 Al (grain size ∼440 nm) processed by gas atomization, cryomilling, and consolidation were studied in the temperature range 523 to 648 K. Also, the creep microstructure developed in the alloy was examined by means of transmission electron microscopy (TEM). The ductility as a function of strain rate exhibits a maximum that shifts to higher strain rates with increasing temperature. An analysis of the experimental data indicates that the true stress exponent is about 2, and the true activation energy is close to that anticipated for boundary diffusion in 5083 Al. These creep characteristics along with the ductility behavior of 5083 Al are a reflection of its creep behavior as a superplastic alloy and not as a solid-solution alloy. In addition, the observation of elongations of more than 300 pct at strain rates higher than 0.1 s−1 is indicative of the occurrence of high-strain-rate (HSR) superplasticity. Microstructural evidence for the occurrence of HSR superplasticity includes the retention of equiaxed grains after deformation, the observation of features associated with the occurrence of grain boundary sliding, and the formation of cavity stringers. Grain size stability during the superplastic deformation of the alloy is attributed to the presence of dispersion particles that are introduced during gas spraying and cryomilling. These particles also serve as obstacles for dislocation motion, which may account for the threshold stress estimated from the creep data of the alloy.

ABSTRACT Sporadic inclusion body myositis (IBM), the commonest myopathy acquired by those aged ov... more ABSTRACT Sporadic inclusion body myositis (IBM), the commonest myopathy acquired by those aged over 50 years, remains without proven treatment. We developed an in vitro disease model, using primary satellite cells, in which overexpression of βAmyloid Precursor Protein or exposure to inflammatory mediators IL1β/TNF-α reproduced salient features of the cellular environment in IBM. With a view to screening pharmaceutical agents, we investigated potential outcome measures relevant to IBM pathology, particularly those where inflammatory and degenerative processes may interact. Using fluorescent imaging, elevated basal cytosolic calcium and disturbed ER calcium handling was demonstrated in myogenic cells overexpressing APP or exposed to IL1β/TNF-α. These potentially pathological disturbances were significantly improved by treatment with arimoclomol, a co-inducer of the cytoprotective heat shock response (HSR). Cytoplasmic redistribution of TAR DNA binding protein (TDP43) from the nucleus is a fundamental feature of IBM tissue. Overexpression of APP and exposure to the inflammatory mediators reproduced this effect in vitro. These degenerative and inflammatory stimuli also triggered nuclear translocation of NfkB, reflecting its activation, a potential mechanism by which pathological processes are sustained in IBM. Redistribution of TDP43 and NFkB was significantly attenuated by Arimoclomol treatment. These data support further investigation of HSR augmentation as a therapeutic strategy in IBM.

Philosophical Transactions of The Royal Society B: Biological Sciences, 2002

All organisms examined to date, respond to a sudden change in environmental temperature with a sp... more All organisms examined to date, respond to a sudden change in environmental temperature with a specific cascade of adaptation reactions that, in some cases, have been identified and monitored at the molecular level. According to the type of temperature change, this response has been termed heat shock response (HSR) or cold shock response (CSR). During the HSR, a specialized sigma factor has been shown to play a central regulatory role in controlling expression of genes predominantly required to cope with heat-induced alteration of protein conformation. In contrast, after cold shock, nucleic acid structure and proteins interacting with the biological information molecules DNA and RNA appear to play a major cellular role. Currently, no cold-specific sigma factor has been identified. Therefore, unlike the HSR, the CSR appears to be organized as a complex stimulon rather than resembling a regulon. This review has been designed to draw a refined picture of our current understanding of the CSR in Bacillus subtilis. Important processes such as temperature sensing, membrane adaptation, modification of the translation apparatus, as well as nucleoid reorganization and some metabolic aspects, are discussed in brief. Special emphasis is placed on recent findings concerning the nucleic acid binding cold shock proteins, which play a fundamental role, not only during cold shock adaptation but also under optimal growth conditions.

IEEE Transactions on Power Delivery, 2009

This paper presents a novel dynamic nonlinear model for Pulsed Corona Discharge (PCD) using Back-... more This paper presents a novel dynamic nonlinear model for Pulsed Corona Discharge (PCD) using Back-Propagation Neural Networks (BPNN). Levenberg-Marquardt (LM) training algorithm which is perfectly suitable for fitting functions is employed. The developed model is based on the voltage-current characteristics of an actual Hybrid-Series Reactor (HSR), and taking into account the practical constrains associated with a real system. The validity and accuracy of the model have been tested in Electromagnetic Transients Program (EMTP), using MODELS language and TACS-91 time-variant controlled resistor. The results clearly demonstrate that BPNNbased model is very robust and effective in precisely emulating the chaotic performance of the PCD.

Over the past 2-3 decades, stellarator power plants have been studied in the U.S., Europe, and Ja... more Over the past 2-3 decades, stellarator power plants have been studied in the U.S., Europe, and Japan as an alternate to the mainline magnetic fusion tokamaks, offering steady state operation and eliminating the risk of plasma disruptions. The earlier 1980s studies suggested large stellarators with an average major radius exceeding 20 m. The most recent development of the compact stellarator concept delivered ARIES-CS -a compact stellarator with 7.75 m average major radius, approaching that of tokamaks. For stellarators, the most important engineering parameter that determines the machine size and cost is the minimum distance between the plasma boundary and mid-coil. Accommodating the breeding blanket and necessary shield within this distance to protect the ARIES-CS superconducting magnet represents a challenging task. Selecting the ARIES-CS nuclear and engineering parameters to produce an economic optimum, modeling the complex geometry for 3-D nuclear analysis to confirm the key parameters, and minimizing the radwaste stream received considerable attention during the design process. These engineering design elements combined with advanced physics helped enable the compact stellarator to be a viable concept. This paper provides a brief historical overview of the progress in designing stellarator power plants and a perspective on the successful integration of the nuclear activity into the final ARIES-CS configuration.

Recent models of Spatial Data Infrastructures (SDIs) are overly simplistic and fail to address th... more Recent models of Spatial Data Infrastructures (SDIs) are overly simplistic and fail to address the dynamic nature, complexity, inter-and intra-jurisdictional nature and important role of partnerships. There is a need by governments and administrators to better understand the complex nature of SDIs to facilitate implementation of this form of infrastructure in an information society.

In this paper we study a self organizing network architecture, Party. Party is a new routing prot... more In this paper we study a self organizing network architecture, Party. Party is a new routing protocol intended to be applied in environments with large number of nodes where the scalability of the routing protocol plays an important role. Party's routing is unique and only depends on the current node's neighborhood. Routing tables are created on the basis of the first hop neighborhood only. We will show the protocol performance with a large number of nodes in the network, and compare it to the legacy ad hoc routing protocols. Results show a large improvement in terms of overhead and throughput.

Journal of Gastrointestinal Cancer

Background Bevacizumab is a humanized monoclonal antibody that blocks vascular endothelial factor... more Background Bevacizumab is a humanized monoclonal antibody that blocks vascular endothelial factor. It demonstrated an efficacy in many cancer types. The standard recommendation of administration is the 90-, 60-, and 30-min infusion sequence for all doses. We evaluated in this study the possibility of reducing infusion time to 10 min for bevacizumab given at 5 or 7.5 mg/kg in metastatic colorectal cancer (MCRC). Patients and Methods All patients who received bevacizumab for MCRC were analyzed. Patients were divided into two groups: Group A (bevacizumab was given in the 90-, 60-, and 30-min infusion sequence) and group B (bevacizumab was given over 10 min). Patients’ medical records were used to identify any hypersensitivity reactions (HSR) possibly related to bevacizumab. Results There were 38 patients in group A and 43 in group B. In group A, 459 doses of bevacizumab were given (286 doses at 5 mg/kg and 173 doses at 7.5 mg/kg). No HSR occurred in this group. In group B, 527 doses of bevacizumab were given (335 doses at 5 mg/kg and 192 doses at 7.5 mg/kg). Only two events of HSR grade 2 were reported in the 7.5 mg/kg infusions. Both of them were easily resolved with symptomatic treatment. Conclusions Bevacizumab 5 or 7.5 mg/kg in MCRC can be infused safely over 10 min.

Metallurgical and Materials Transactions A-physical Metallurgy and Materials Science, 2006

The ductility and creep of bulk ultra-fine-grained (UFG) 5083 Al (grain size ∼440 nm) processed b... more The ductility and creep of bulk ultra-fine-grained (UFG) 5083 Al (grain size ∼440 nm) processed by gas atomization, cryomilling, and consolidation were studied in the temperature range 523 to 648 K. Also, the creep microstructure developed in the alloy was examined by means of transmission electron microscopy (TEM). The ductility as a function of strain rate exhibits a maximum that shifts to higher strain rates with increasing temperature. An analysis of the experimental data indicates that the true stress exponent is about 2, and the true activation energy is close to that anticipated for boundary diffusion in 5083 Al. These creep characteristics along with the ductility behavior of 5083 Al are a reflection of its creep behavior as a superplastic alloy and not as a solid-solution alloy. In addition, the observation of elongations of more than 300 pct at strain rates higher than 0.1 s−1 is indicative of the occurrence of high-strain-rate (HSR) superplasticity. Microstructural evidence for the occurrence of HSR superplasticity includes the retention of equiaxed grains after deformation, the observation of features associated with the occurrence of grain boundary sliding, and the formation of cavity stringers. Grain size stability during the superplastic deformation of the alloy is attributed to the presence of dispersion particles that are introduced during gas spraying and cryomilling. These particles also serve as obstacles for dislocation motion, which may account for the threshold stress estimated from the creep data of the alloy.

ABSTRACT Sporadic inclusion body myositis (IBM), the commonest myopathy acquired by those aged ov... more ABSTRACT Sporadic inclusion body myositis (IBM), the commonest myopathy acquired by those aged over 50 years, remains without proven treatment. We developed an in vitro disease model, using primary satellite cells, in which overexpression of βAmyloid Precursor Protein or exposure to inflammatory mediators IL1β/TNF-α reproduced salient features of the cellular environment in IBM. With a view to screening pharmaceutical agents, we investigated potential outcome measures relevant to IBM pathology, particularly those where inflammatory and degenerative processes may interact. Using fluorescent imaging, elevated basal cytosolic calcium and disturbed ER calcium handling was demonstrated in myogenic cells overexpressing APP or exposed to IL1β/TNF-α. These potentially pathological disturbances were significantly improved by treatment with arimoclomol, a co-inducer of the cytoprotective heat shock response (HSR). Cytoplasmic redistribution of TAR DNA binding protein (TDP43) from the nucleus is a fundamental feature of IBM tissue. Overexpression of APP and exposure to the inflammatory mediators reproduced this effect in vitro. These degenerative and inflammatory stimuli also triggered nuclear translocation of NfkB, reflecting its activation, a potential mechanism by which pathological processes are sustained in IBM. Redistribution of TDP43 and NFkB was significantly attenuated by Arimoclomol treatment. These data support further investigation of HSR augmentation as a therapeutic strategy in IBM.

Philosophical Transactions of The Royal Society B: Biological Sciences, 2002

All organisms examined to date, respond to a sudden change in environmental temperature with a sp... more All organisms examined to date, respond to a sudden change in environmental temperature with a specific cascade of adaptation reactions that, in some cases, have been identified and monitored at the molecular level. According to the type of temperature change, this response has been termed heat shock response (HSR) or cold shock response (CSR). During the HSR, a specialized sigma factor has been shown to play a central regulatory role in controlling expression of genes predominantly required to cope with heat-induced alteration of protein conformation. In contrast, after cold shock, nucleic acid structure and proteins interacting with the biological information molecules DNA and RNA appear to play a major cellular role. Currently, no cold-specific sigma factor has been identified. Therefore, unlike the HSR, the CSR appears to be organized as a complex stimulon rather than resembling a regulon. This review has been designed to draw a refined picture of our current understanding of the CSR in Bacillus subtilis. Important processes such as temperature sensing, membrane adaptation, modification of the translation apparatus, as well as nucleoid reorganization and some metabolic aspects, are discussed in brief. Special emphasis is placed on recent findings concerning the nucleic acid binding cold shock proteins, which play a fundamental role, not only during cold shock adaptation but also under optimal growth conditions.

IEEE Transactions on Power Delivery, 2009

This paper presents a novel dynamic nonlinear model for Pulsed Corona Discharge (PCD) using Back-... more This paper presents a novel dynamic nonlinear model for Pulsed Corona Discharge (PCD) using Back-Propagation Neural Networks (BPNN). Levenberg-Marquardt (LM) training algorithm which is perfectly suitable for fitting functions is employed. The developed model is based on the voltage-current characteristics of an actual Hybrid-Series Reactor (HSR), and taking into account the practical constrains associated with a real system. The validity and accuracy of the model have been tested in Electromagnetic Transients Program (EMTP), using MODELS language and TACS-91 time-variant controlled resistor. The results clearly demonstrate that BPNNbased model is very robust and effective in precisely emulating the chaotic performance of the PCD.

Over the past 2-3 decades, stellarator power plants have been studied in the U.S., Europe, and Ja... more Over the past 2-3 decades, stellarator power plants have been studied in the U.S., Europe, and Japan as an alternate to the mainline magnetic fusion tokamaks, offering steady state operation and eliminating the risk of plasma disruptions. The earlier 1980s studies suggested large stellarators with an average major radius exceeding 20 m. The most recent development of the compact stellarator concept delivered ARIES-CS -a compact stellarator with 7.75 m average major radius, approaching that of tokamaks. For stellarators, the most important engineering parameter that determines the machine size and cost is the minimum distance between the plasma boundary and mid-coil. Accommodating the breeding blanket and necessary shield within this distance to protect the ARIES-CS superconducting magnet represents a challenging task. Selecting the ARIES-CS nuclear and engineering parameters to produce an economic optimum, modeling the complex geometry for 3-D nuclear analysis to confirm the key parameters, and minimizing the radwaste stream received considerable attention during the design process. These engineering design elements combined with advanced physics helped enable the compact stellarator to be a viable concept. This paper provides a brief historical overview of the progress in designing stellarator power plants and a perspective on the successful integration of the nuclear activity into the final ARIES-CS configuration.

Recent models of Spatial Data Infrastructures (SDIs) are overly simplistic and fail to address th... more Recent models of Spatial Data Infrastructures (SDIs) are overly simplistic and fail to address the dynamic nature, complexity, inter-and intra-jurisdictional nature and important role of partnerships. There is a need by governments and administrators to better understand the complex nature of SDIs to facilitate implementation of this form of infrastructure in an information society.

In this paper we study a self organizing network architecture, Party. Party is a new routing prot... more In this paper we study a self organizing network architecture, Party. Party is a new routing protocol intended to be applied in environments with large number of nodes where the scalability of the routing protocol plays an important role. Party's routing is unique and only depends on the current node's neighborhood. Routing tables are created on the basis of the first hop neighborhood only. We will show the protocol performance with a large number of nodes in the network, and compare it to the legacy ad hoc routing protocols. Results show a large improvement in terms of overhead and throughput.

Journal of Gastrointestinal Cancer

Background Bevacizumab is a humanized monoclonal antibody that blocks vascular endothelial factor... more Background Bevacizumab is a humanized monoclonal antibody that blocks vascular endothelial factor. It demonstrated an efficacy in many cancer types. The standard recommendation of administration is the 90-, 60-, and 30-min infusion sequence for all doses. We evaluated in this study the possibility of reducing infusion time to 10 min for bevacizumab given at 5 or 7.5 mg/kg in metastatic colorectal cancer (MCRC). Patients and Methods All patients who received bevacizumab for MCRC were analyzed. Patients were divided into two groups: Group A (bevacizumab was given in the 90-, 60-, and 30-min infusion sequence) and group B (bevacizumab was given over 10 min). Patients’ medical records were used to identify any hypersensitivity reactions (HSR) possibly related to bevacizumab. Results There were 38 patients in group A and 43 in group B. In group A, 459 doses of bevacizumab were given (286 doses at 5 mg/kg and 173 doses at 7.5 mg/kg). No HSR occurred in this group. In group B, 527 doses of bevacizumab were given (335 doses at 5 mg/kg and 192 doses at 7.5 mg/kg). Only two events of HSR grade 2 were reported in the 7.5 mg/kg infusions. Both of them were easily resolved with symptomatic treatment. Conclusions Bevacizumab 5 or 7.5 mg/kg in MCRC can be infused safely over 10 min.