ayman mohamed - Academia.edu (original) (raw)

Papers by ayman mohamed

Cureus

Immune checkpoint inhibitors are becoming of more use as clinicians are prescribing them for pati... more Immune checkpoint inhibitors are becoming of more use as clinicians are prescribing them for patients with different malignancies. As their use continues to increase, clinicians must be aware of the side effects, which are autoimmune in nature. Autoimmune diabetes has been described in the past while patients were being treated with programmed cell death protein 1 (PD-1) inhibitors, but it usually occurs after the patient's fourth or fifth cycle. In this case presentation, we describe a patient with no history of type 1 or 2 diabetes presenting to the emergency department with severe diabetic ketoacidosis. At the time of presentation, he was on his 22nd cycle of nivolumab for metastatic renal cell carcinoma. The patient was eventually treated successfully, but upon discharge, he was prescribed a large dose of insulin regimen to control his blood sugar levels at home. We attributed his new diagnosis of insulin-dependent diabetes to the PD-1 inhibitor nivolumab.

2020 IEEE International Symposium on Circuits and Systems (ISCAS)

In this paper, we present a mixed-logic dynamical (MLD) system model that allows for an iron-clad... more In this paper, we present a mixed-logic dynamical (MLD) system model that allows for an iron-clad prediction of the stability of Incremental Sigma Delta (I-ΣΔ) modulators. The model extends the mixed logic dynamical description of freely-running Sigma-Delta (ΣΔ) modulators with single-bit quantizers presented in [1] to the multibit case. Moreover, we use the derived model to compare I-ΣΔs with different loop filter orders and different number of quantizer levels concerning their stability.

2020 IEEE SENSORS

In this paper, we propose a low noise CMOS frontend for a Point-of-Care (PoC) biosensing platform... more In this paper, we propose a low noise CMOS frontend for a Point-of-Care (PoC) biosensing platform based on tunnel magnetoresistance (TMR) as sensors. The integration of a low noise and low power integrated circuit (IC) with the TMR sensors reduces power consumption compared to a realization with discrete electronics and, thereby, paves the way towards a portable diagnostic system. The proposed chip uses a DCcoupled fully differential difference amplifier (FDDA) to amplify the minute signals generated by magnetic nanotags (MNTs) that will be used as biomarkers in the target biosensing application. The FDDA features a gain of around 60 dB with a suitable offset calibration scheme to deal with the large DC offsets caused by TMR and/or magnetic field mismatch. The ability to deal with varying DC fields is crucial for a portable setup that is intended to be used in unshielded environments outside the lab. The offset cancellation is achieved by two on-chip current steering DACs that can accommodate TMR resistances between 535 ⌦ and 4.7 k⌦. The presented chip is manufactured in a 180 nm SOI CMOS technology and features a thermal noise floor of 7 nV/ p Hz. It consumes a total of 7.7 mA from a 1.8 V supply.

Perfusion

Objectives We aim at identifying the changes in venous blood saturation values that associates in... more Objectives We aim at identifying the changes in venous blood saturation values that associates intra-aortic balloon pump (IABP) in cardiac surgery patients with reduced left ventricular function (LVF). Methods A retrospective observational study was conducted in a cardiothoracic intensive care unit (CTICU) in a tertiary cardiac center over 5 years in Qatar. A total of 114 patients with at least moderate impairment of LVF with ejection fraction (EF) less than 40% were enrolled. According to the association of IABP, patients were segregated into two groups with and without IABP (groups 1, 40 patients and group 2, 74 patients). Sequential arterial and venous blood gases were analyzed. The primary outcome was to analyze the changes in the central venous saturation (ScvO2) in both groups and the secondary outcome was to analyze whether these changes affect the overall outcome in terms of intensive care unit (ICU) length of stay. Results There was no significant difference between both gr...

Special Issue (specialissue), 2018

Crop that are currently underutilized can play a major role in diversifying food sources and comb... more Crop that are currently underutilized can play a major role in diversifying food sources and combating climate variability. One major obstacle for wider adoption of these species is the lack of information on the geographic areas where these crops are currently grown. These crops are typically grown in marginal lands through subsistence agriculture. At present, there is no global database and no efficient procedure that allows users to acquire cropping patterns of underutilised crops. The proposed solution identifies underutilized cropping patterns using online search engine data. The target is to determine global public interest in underutilised crops over time through search engine data. This identifies possible crop utilisation patterns, trends and interest pertaining to underutilised crops over time. As a proof of concept, we collected a set of keyword synonymous of Bambara groundnut (BG), from local and international databases and research publications. Using the Google AdWords service and 40 different terms for BG, we were able to gather search event data for two years, at the city level. Preliminary analysis done through a software prototype shows that the data provides new insights as to how BG search events are distributed and how this data can be used to delineate current areas where BG grows and what are the characteristics of their value chains. For evaluation purposes, we compared our BG results with the crop's known network of BG growers and researchers, and confirmed that the results not only matched known regions of the network but also proposed several new ones that need to be evaluated. The results suggest that the proposed solution provides significant indicators for possible cropping patterns and/or research interests around the world.

Stress and Health

COVID-19 is a world disaster. In response to COVID-19 quarantine, stress, anxiety, and depression... more COVID-19 is a world disaster. In response to COVID-19 quarantine, stress, anxiety, and depression may easily develop which negatively affect immunity and decrease the patient's response against the COVID-19 virus. This study investigated the effect of an integrated intervention combining Cognitive-Behavioral Stress Management (CBSM) and progressive muscle relaxation (PMRs) on immune biomarkers and disease severity and progression in patients with COVID-19 and the period to which these changes last. Thirty patients with mild or moderate COVID-19 were randomly distributed into intervention and control groups. The intervention group performed an integrated intervention combining CBSM and PMRs. There were three outcome measures including blood immune markers, salivary immunoglobulin A, and Wisconsin scale. Two-week post-intervention, there were significant differences between groups in the Wisconsin scale total score, Leucocytes, Lymphocytes, Interleukin-6, and Immunoglobulin-A. While there were non-significant differences between both groups in Interleukin-10 and TNF-α. The significant differences between groups in the Wisconsin scale total score, Leucocytes, Lymphocytes, Interleukin-6, and Immunoglobulin-A significantly continued 1-week as a follow-up. This study concluded that performing an integrated intervention combining CBSM and PMRs for 2-weeks significantly increases immune biomarkers mainly Leucocytes, Lymphocytes, Interleukin-10, and Interleukin-6 along with S-IgA. Also, this protocol significantly decreases disease severity and associated stress, anxiety, and depression; and enhances the quality of life in patients with COVID-19. The study was retrospectively registered with NCT04998708. This article is protected by copyright. All rights reserved.

Suez Canal University Medical Journal, 2022

Background: The paperless partograph refers to monitoring progress of labor and reaching to an ac... more Background: The paperless partograph refers to monitoring progress of labor and reaching to an accurate decision for intervention to ensure safe delivery. It needs no graph paper, no extra time to do in comparison to routine partograph. Aim: to reevaluate effect of using paperless partograph on the management and outcome of labor at to prevent prolonged labor and its complications and improving quality of labor in Labor ward at women health hospital Assiut university. Subjects and Methods: The study was conducted from 1st March 2018 to last February 2019 on Women Health Hospital, Assiut University, Egypt, at reception (emergency) unit and it was prospective observational analytical study. Sample of 800 women who met the criteria of; gestational age from 37 to 42 weeks, singleton pregnancy and with cephalic presentation. The data were collected by using the paperless partograph model. Results: Mean age of the participants was 25.6 years and mean of gestational age 39.1weeks and 87% were multipara. Mean duration for delivery after Alert ETD was 3.5 ±2.1 hours in primigravida and 3.3 ±2.1 hours in multipara. Mean Apgar score of the newborn after 5 minutes was 9.4. Conclusion: Paperless partograph was found to be effective positively on the management and the outcome of labor.

ESSCIRC 2021 - IEEE 47th European Solid State Circuits Conference (ESSCIRC), 2021

In this paper, we present a widely tunable transimpedance amplifier (TIA) with a dc servo loop an... more In this paper, we present a widely tunable transimpedance amplifier (TIA) with a dc servo loop and an optional bandwidth extension. All resistors are implemented as multielement pseudo-resistors, which feature high linearity, robustness against process and temperature variations, and a very wide tuning range of more than five decades. While state-of-the-art TIAs are mainly implemented with either resistive or capacitive feedback, the proposed TIA uses a capacitive-resistive feedback network to combine the best of both topologies. The TIA features a noise floor of 0.6 fA/✓Hz at its maximum transimpedance of 150 GΩ and a bandwidth of 2.9 MHz at its minimum transimpedance of 440 kΩ. A subsequent inverting amplifier stage provides an optional pole-zero compensation to extend the TIA's overall bandwidth by a factor of up to 180 or with an absolute limit of 2.3 MHz. An additional dc servo loop, which incorporates a tunable integrator and a tunable dc feedback resistor, can be used to prevent large dc currents from flowing through the main signal path. Its dc transimpedance can be adjusted separately from the ac transimpedance, and the crossover frequency is adjustable over a range of more than five decades. The TIA occupies 0.3 mm2 of chip area and has a power consumption of 40 mW from a 1.8-V supply.

Sensors, 2022

In the era of the “Industry 4.0” revolution, self-adjusting and unmanned machining systems have g... more In the era of the “Industry 4.0” revolution, self-adjusting and unmanned machining systems have gained considerable interest in high-value manufacturing industries to cope with the growing demand for high productivity, standardized part quality, and reduced cost. Tool condition monitoring (TCM) systems pave the way for automated machining through monitoring the state of the cutting tool, including the occurrences of wear, cracks, chipping, and breakage, with the aim of improving the efficiency and economics of the machining process. This article reviews the state-of-the-art TCM system components, namely, means of sensing, data acquisition, signal conditioning and processing, and monitoring models, found in the recent open literature. Special attention is given to analyzing the advantages and limitations of current practices in developing wireless tool-embedded sensor nodes, which enable seamless implementation and Industrial Internet of Things (IIOT) readiness of TCM systems. Additi...

<sec> <title>BACKGROUND</title> COVID 19 is a self limited disease, in... more <sec> <title>BACKGROUND</title> COVID 19 is a self limited disease, in which the strength of immunity play a key role in its management. Aerobic exercises has been documented to enhance the immunity </sec> <sec> <title>OBJECTIVE</title> This review was conducted to systematically provide aerobic exercises recommendations and specifications for patients with COVID-19. </sec> <sec> <title>METHODS</title> : a systematic search was conducted through MEDLINE (PubMed), Science Direct, Web of Science, Scopus, Bireme, Cochrane Library, and SciELO databases. The search included the following keywords immune, Aerobic training, human and immune cells. </sec> <sec> <title>RESULTS</title> Eleven studies met the inclusion and exclusion criteria of this search. The most used exercise prescriptions included: the mode included walking, cycling or running, the duration ranged from 18 to 60 min, the intensity ranged from 55% to 80% of VO2max or 60%-80% of maximum heart rate, and the frequency ranged from 1 to 3 times /week. The main increased immunological biomarkers were leukocytes, linfocytes, neutrophils, monocytes, eosinophils, IL-6, CD16-56, CD16, CD4, CD3, CD8, and CD19. </sec> <sec> <title>CONCLUSIONS</title> This review demonstrated a regular aerobic exercise consists of cycling ergometer or walking, at intensity, 55% - 80% of VO2max or 60%-80% of maximum heart rate, 2-3 sessions/week, 18-60 min/session can enhance immune functions without producing exhaustion. </sec>

2019 17th IEEE International New Circuits and Systems Conference (NEWCAS), 2019

In this paper, we present a new method to include finite-impulse-response (FIR) feedback digital-... more In this paper, we present a new method to include finite-impulse-response (FIR) feedback digital-to-analog converters (DACs) in continuous-time (CT) Incremental Sigma-Delta (I-ΣΔ) analog-to-digital converters (ADC), which minimizes transient overshoots and thereby maximizes the modulator's stability. More specifically, it can be shown that increasing the number of FIR taps in I-ΣΔ feedback DACs could lead to instability or a reduced maximum stable amplitude (MSA), even when using a proper compensation path. However, by presetting the FIR feedback to a voltage close to the input signal, a larger number of FIR taps can be used, increasing the jitter robustness of the CT I-ΣΔ. This presetting is achieved using a low resolution Nyquist rate ADC to preset the FIR taps. Moreover, presetting the FIR feedback slightly increases the modulator's MSA and signal-to-noise ratio compared to a non-return-to-zero (NRZ) feedback. To validate the proposed presetting approach, a third-order I-ΣΔ-ADC employing a 12-tap FIR DAC with presetting using a 4-bit flash ADC is compared against a conventional NRZ DAC and a conventional FIR DAC without presetting in MATLAB/Simulink.

ABSTRACT Management water usage becomes an important issue in Egypt, as a result of the continuou... more ABSTRACT Management water usage becomes an important issue in Egypt, as a result of the continuous increase in Egypt's population and its Nile waters share stabled. Optimum cultivate water usage will lead to reduce the wasted water. This work aids optimizing crop water usage by developing a generic design for irrigation expert system for trees. The irrigation expert system aims to provide the farmers by the irrigation expertise to determine the exact water needed at exact time according to the crop requirements and the environmental factors which effect factors like the temperature, soil type, source of water, etc. It was experimented on developing irrigation expert system for Mango.

Accident Analysis & Prevention, 2022

In recent years, pedestrian and bicycle safety have emerged to be of major concern to Federal and... more In recent years, pedestrian and bicycle safety have emerged to be of major concern to Federal and selected States in the US. With the transition to the mobility of people, pedestrian and bicycle safety has become more prevalent for governmental agencies to address and prioritize for strategic constructing. It was crucial to address the pedestrian- vehicular conflict within Florida as it was reported in the “Dangerous by Design” report as having the highest four (4) pedestrian incident locations in the country. This paper investigates correlation between pedestrian safety and sidewalk/bicycle-lane gaps within Florida Department of Transportation (FDOT) District 5. A wide array of Geographic Information Systems (GIS) information associated with the sidewalk/bicycle lane gaps and the safety data was secured by FDOT. The data included all the Roadway Characteristics Inventory (RCI) within the district. Crash data combined with other geometric design data, traffic data, and census data were used to develop a statistical model. The results showed that presence of sidewalk along roadway segments is one of the main factors that have significant impact on the expected number of pedestrian crashes at a specific location. Other factors included daily traffic volumes, roadway category, specifically along urban two-way divided and undivided arterials with 4-6 lanes as well as the average population within half-mile radius surrounding the crash location. The analysis also concluded that the likelihood of a pedestrian crash along roadways with no sidewalk is 3 times greater than the likelihood of a crash with the presence of a sidewalk.

Engineering Research Journal, 2020

This paper investigates the residential building energy needs in Egypt. Firstly, the energy needs... more This paper investigates the residential building energy needs in Egypt. Firstly, the energy needs of residential building are evaluated in compliance with Energy Efficiency Residential Building Code as a base case. Then, Energy Efficiency Measures (EEMs) defined as measures that reduce energy consumption whilst maintaining the same or better indoor climate conditions are implemented as a modified case using building simulation technique. The considered EEMs include adding thermal insulation to the exterior walls, adding external shading, using lighting fixture with high efficacy and using window glazing type with high thermal and radiation characteristic. Finally, a comparison between the base and modified cases is made.The reported results showed that the thermal cooling demand, heating demand and total electricity demand of the base case are 130 kWh/m 2 .a, 6.5 kWh/m 2 a and 114 kWh/m 2 .a, respectively. It is found that as the overall heat transfer coefficient of external wall decreases from 1.7 W/m 2 K to 0.58W/m 2 K causes the cooling and heating demands to decrease by 7% and 60%, respectively. Adding shading with a projection factor of 0.9 for all external windows decreases the cooling demands by 13%. Using double glazing decreases the cooling and heating demands by 14% and 30%, respectively. Installing LED lighting type reduces the annual space cooling demand and electricity consumption by 17% and 26%, respectively. The values of each EEM which are the lowest energy needs, combining to get the optimized case in which the cooling demand, total electricity and the heating demand decrease by 34%, 17% and 11% respectively.

Archive of Applied Mechanics, 2021

Most recently, the whole world is struggling against the virulent pandemic COVID-19. Due to the u... more Most recently, the whole world is struggling against the virulent pandemic COVID-19. Due to the unbounded global spread of the disease, having biosensors with high performance such as high sensitivity and accuracy is of utmost importance. In this paper, the effects of various parameters on the behaviors of microbiosensors are investigated in order to enhance their performance. These parameters are related to the geometry and material, and they are assumed to be gradually changing in the longitudinal direction of the biosensor according to a power law. Therefore, they are called functionally graded geometrical and material parameters. Another aspect is when considering microcantilever-based biosensors, the main behavior parameter is the deflection at the free end. In the analyses, the influences of the surface stress and van der Waals intermolecular forces are taken into account. Also, the total energy of the beam, which is the combination of the van der Waals energy and the elastic strain energy, is accomplished. In addition, the equivalent force causing the deflection is also evaluated using Castigliano method for two cases. These cases account for a concentrated force at the free end and a distributed load along the biosensor, respectively. Since the governing equations account for the size dependency and the considered parameters are functions of the position, the solution is too complex to be achieved analytically, and therefore, numerical methods are applied. For uniform biosensors made of homogeneous materials, or in other words when all parameters are not varying with the position, the obtained results are compared with those in the literature, and good agreement is obtained. On the other hand, the performance, which include sensitivity and limit of detection, of functionally graded biosensors can be enhanced by proper choices of the considered parameters and the corresponding exponent of the gradation function.

Energies, 2021

This article describes the development and testing of a modified, semi-empirical ONERA dynamic st... more This article describes the development and testing of a modified, semi-empirical ONERA dynamic stall model for an airfoil with a trailing edge flap—a “smart airfoil”—pitching at reduced frequencies up to 0.1. The Reynolds number is 105. The model reconstructs the load fluctuations associated with the shedding of multiple dynamic stall vortices (DSVs) in a time-marching solution, which makes it suitable for real-time control of a trailing edge flap (TEF). No other model captures the effect of the DSVs on the aerodynamic loads on smart airfoils. The model was refined and tuned for force measurements on a smart NACA 643-618 airfoil model that was pitching with an inactive TEF and was validated against the measurements when the TEF was activated. A substantial laminar separation bubble can develop on this airfoil, which is challenging for modelers of the unsteady response. A closed-loop controller was designed offline in SIMULINK, and the output of the controller was applied to the TEF ...

2020 IEEE International Symposium on Circuits and Systems (ISCAS), 2020

In this paper, we present a CMOS-based miniaturized magnetic resonance (MR) system for magnetic f... more In this paper, we present a CMOS-based miniaturized magnetic resonance (MR) system for magnetic field and trajectory mapping incorporating an electromagnetic interference (EMI) robust optical link. The system consists of a custom-designed, CMOS-based active NMR field probe, a custom-designed, single-bit ΣΔ modulator and a commercial optical link. The low-IF architecture of the transceiver ASIC, reduces the required bandwidth in the digitizer to a few hundred kilohertz, enabling the use of a single-bit ΣΔ modulator, whose high frequency, one bit data stream is ideally suited for feeding the following optical link. The custom ΣΔ modulator uses a third order loop filter and employs a 12-tap FIR DAC to increase its robustness against clock jitter. It is manufactured in a 0.18 μm CMOS technology and achieves an SNDR of 72.19 dB over a Nyquist bandwidth of 800 kHz. In the proposed setup, the 1-bit output stream of the ΣΔ modulator directly feeds the driver of a commercial optical fiber link to transmit the NMR data from inside the NMR magnet to the remotely located digital signal processing unit with a very high robustness against EMI. In-situ NMR experiments with a 1.45 T benchtop magnet using a silicone sample demonstrate the very good performance of the overall system, achieving a frequency resolution of 12.6 Hz or 200 ppb in the estimation of the sample's NMR resonance frequency. This corresponds to an effective magnetic field resolution of 290 nT.

To date there are no clear or uniform standards for a method to measure pedestrian crash rates an... more To date there are no clear or uniform standards for a method to measure pedestrian crash rates and compare it against a statewide average. In this paper, a novel methodology to measure pedestrian c ...

Engineering Research Journal, 2020

According to sustainable development strategy, the Egyptian government objective is reducing the ... more According to sustainable development strategy, the Egyptian government objective is reducing the energy consumption and greenhouse gas emissions by 14% and 10% respectively by 2030. So, the national trend and the target of this phase is reducing the energy consumption in the buildings sector by applying the Net Zero Energy Building (NZEB) strategies to the new buildings and refurbishment the existing buildings to reduce the demand and apply on-site generation to reach NZEB target. This study starts with the analysis of the current situation of an exemplary existing administrative building in Cairo, Egypt. Consequently, the economic feasibility of converting exemplary existing administrative to be nearly and Net ZEB is analyzed. Generally speaking, the guideline to achieve this has three steps; (1) reducing the energy consumption by suggesting retrofitting strategies, (2) implementing energy efficiency technologies, (3) installing energy generation systems. OpenStudio as a cross-platform collection of software tools used to build the model where it is simulated by EnergyPlus as an energy modeling engine. The energy consumption is validated by comparing it with the real energy consumption of the existing building.

Cureus

2020 IEEE International Symposium on Circuits and Systems (ISCAS)

2020 IEEE SENSORS

Perfusion

Special Issue (specialissue), 2018

Stress and Health

Suez Canal University Medical Journal, 2022

ESSCIRC 2021 - IEEE 47th European Solid State Circuits Conference (ESSCIRC), 2021

Sensors, 2022

2019 17th IEEE International New Circuits and Systems Conference (NEWCAS), 2019

Accident Analysis & Prevention, 2022

Engineering Research Journal, 2020

Archive of Applied Mechanics, 2021

Energies, 2021

2020 IEEE International Symposium on Circuits and Systems (ISCAS), 2020

Engineering Research Journal, 2020