Publications by authors named "Karar A"

Background: This study was conducted to assess serum levels of folate and vitamin B12 in overweight and obese pregnant women.

Methods: A cross-sectional study was conducted at Saad Abualila Hospital, Sudan. Clinical data were collected through questionnaires and body mass index (BMI) was computed from weight and height.

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To combat chromatic dispersion (CD) in intensity modulation and direct detection (IM/DD) systems, three chirp-free demonstrations are experimentally performed with an iterative pre-electronic dispersion compensation (pre-EDC) algorithm at the transmitter end, for 28 GBaud non-return-to-zero on-off keying (NRZ-OOK), 56 GBaud NRZ-OOK and 28 GBaud four-level pulse-amplitude-modulation (PAM-4) signals, over distances of 100 km, 50 km and 40 km of single mode fiber (SMF), respectively. The iterative pre-EDC algorithm is based on the Gerchberg-Saxton (GS) algorithm, which treats the unconstrained phase at the direct detection receiver as a degree of freedom. At the receiver side, only a linear fractionally-spaced (T/2) post-feed-forward equalizer (post-FFE) is employed to combat the residual inter-symbol interference (ISI).

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A finite-difference time-domain method is developed for studying the plasmon enhancement of light absorption from vertically aligned GaAs nanowire arrays decorated with Au nanoparticles. Vertically aligned GaAs nanowires with a length of 1 µm, a diameter of 100 nm and a periodicity of 165-500 nm are functionalized with Au nanoparticles with a diameter between 30 and 60 nm decorated in the sidewall of the nanowires. The results show that the metal nanoparticles can improve the absorption efficiency through their plasmonic resonances, most significantly within the near-bandgap edge of GaAs.

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The design, micro-fabrication, and characterization of a resistance temperature detector (RTD) based micro sensor for minimally invasive breathing analysis and monitoring is presented. Experimental results demonstrate that the change in air temperature while inhaling and exhaling can be transduced into a time varying electrical signal, which is subsequently used to determine the breathing frequency (respiratory rate). The RTD is placed into a Wheatstone bridge to simultaneously reduce the sensor's output noise and improve overall system accuracy.

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In this paper, a customizable wearable 3D-printed bionic arm is designed, fabricated, and optimized for a right arm amputee. An experimental test has been conducted for the user, where control of the artificial bionic hand is accomplished successfully using surface electromyography (sEMG) signals acquired by a multi-channel wearable armband. The 3D-printed bionic arm was designed for the low cost of 295 USD, and was lightweight at 428 g.

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Background: Mobile health technology offers promising means to implement public health strategies for the prevention and management of chronic conditions. However, at the moment, there is a dearth of both; specific mobile health tools tailored for the knowledge and language needs of Indian population; as well as enough systematic and scientific clinical data to analyse their impact in varied Indian socioeconomic and disease populations.

Objective: To develop a smartphone-based bilingual educational mobile application for heart patients and pilot test in an Indian clinical setting.

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We report on the ion-induced anisotropic deformation in nickel oxide nanoparticles prepared by conventional sol-gel technique. Colloidal-like NiO nanoparticles with an average diameter of about 40-50 nm embedded in a SiO layer change their shape dramatically under swift heavy ion irradiation with 32 MeV Cu ions at room temperature and normal incidence. Transmission electron microscopy analysis show irradiation induced shape transformation from nearly spherical nanoparticles into oblate nanorods at a rate that increases with ion fluence.

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Information overload is a significant problem in the digital age of healthcare and plays key a role in diagnostic errors, near misses, and patient safety, especially in critical care settings. Because of this, we propose a new mixed-methods approach for evaluating EHR-related information overload on clinicians in the ICU. We describe a three-part approach to better understand ICU clinicians' information needs and workflow as they relate to the EHR, and to explore the effects of the EHR on provider workload, performance, and satisfaction.

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The formation of calcium carbonate CaCO3 in water has some important implications in geoscience researches, ocean chemistry studies, CO2 emission issues and biology. In industry, the scaling phenomenon may cause technical problems, such as reduction in heat transfer efficiency in cooling systems and obstruction of pipes. This paper focuses on the study of the glutamic acid (GA) for reducing CaCO3 scale formation on metallic surfaces in the water of Bir Aissa region.

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We have fabricated a waveguide integrated monolithic silicon infrared detector. The photodiode consists of a p-i-n junction across a silicon-on-insulator (SOI) rib waveguide. Absorption is due to surface-states at the silicon/air interface of the waveguide.

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Perturbation based nonlinearity pre-compensation has been performed for a 128 Gbit/s single-carrier dual-polarization 16-ary quadrature-amplitude-modulation (DP 16-QAM) signal. Without any performance degradation, a complexity reduction factor of 6.8 has been demonstrated for a transmission distance of 3600 km by combining symmetric electronic dispersion compensation and root-raised-cosine pulse shaping with a roll-off factor of 0.

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We have fabricated monolithic silicon avalanche photodiodes capable of 10 Gbps operation at a wavelength of 1550 nm. The photodiodes are entirely CMOS process compatible and comprise a p-i-n junction integrated with a silicon-on-insulator (SOI) rib waveguide. Photo-generation is initiated via the presence of deep levels in the silicon bandgap, introduced by ion implantation and modified by subsequent annealing.

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We propose and numerically demonstrate a high absorption hybrid-plasmonic-based metal semiconductor metal photodetector (MSM-PD) comprising metal nanogratings, a subwavelength slit and amorphous silicon or germanium embedded metal nanoparticles (NPs). Simulation results show that by optimizing the metal nanograting parameters, the subwavelength slit and the embedded metal NPs, a 1.3 order of magnitude increase in electric field is attained, leading to 28-fold absorption enhancement, in comparison with conventional MSM-PD structures.

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The generation of differential-phase-shift keying (DPSK) signals is demonstrated using a directly modulated passive feedback laser at 10.709-Gb/s, 14-Gb/s and 16-Gb/s. The quality of the DPSK signals is assessed using both noncoherent detection for a bit rate of 10.

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A novel electronic dispersion pre-compensation scheme for a directly modulated laser is described and experimentally demonstrated for transmission distances beyond 200 km using a low-cost laser packaged for 2.5-Gb/s while operated at 10.709-Gb/s.

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The implications of increasing the symbol rate for a given digital-to-analog converter (DAC) sampling rate are investigated by considering the generation of 112 Gbit/s PM 16-QAM signals (14 Gsym/s) using a 21 GSa/s DAC with 6-bit resolution.

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Multiple myeloma (MM) is a systemic malignancy of pathologic plasma cells that is treatable with chemotherapeutic agents and irradiation, but rarely curable. The spectrum of neurological complications of MM is diverse; however, involvement of MM in the cerebrospinal fluid and leptomeningeal infiltration is considered rare. There have been many reviews of central nervous system complications in MM but there are none on intracranial and leptomeningeal infiltration of MM.

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Objective: To study the relationship between postoperative infectious complications and glycemic control for diabetic patients in an orthopedic hospital in Kuwait.

Subjects And Methods: Patients who underwent surgical orthopedic procedures between 2006 and 2007 were identified to provide demographic and clinical informations including age, gender, type of surgery, length of operation, HbA(1c) values, nature of specimens and species of the isolated pathogens. HbA(1c) <7% was used as the breaking point for diabetic control and occurrence of postoperative complications.

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