Ahmed Essam - Academia.edu (original) (raw)

Papers by Ahmed Essam

Ground-based and Airborne Instrumentation for Astronomy VIII, 2020

The Kottamia Faint Imaging Spectro-Polarimeter (KFISP) has been recently developed, commissioned ... more The Kottamia Faint Imaging Spectro-Polarimeter (KFISP) has been recently developed, commissioned and mounted to the Cassegrain focus of the 1.88m telescope at Kottamia astronomical observatory, Egypt. The KFISP instrument demagnified the Kottamia 1.88m telescope Cassegrain focus from a f/18 with a plate scale 6.09"/mm to f/6.14 with a plate scale of 17.8"/mm. A liquid Nitrogen cooled CCD camera with a 2048×2048 pixels and 13.5-micron square pixel size is fixed to the KFISP through an integrated camera lens. In this paper we describe the camera system, performance, and its software control. As well, KFISP motion control and its software will be introduced. In addition, detailed description of the instrument performance and the results obtained from its operation will be presented.

Comprehensive genomic databases offer unprecedented opportunities towards effective tailored stra... more Comprehensive genomic databases offer unprecedented opportunities towards effective tailored strategies for the prevention and treatment of disease. The integration of genomic and phenotypic data from diverse ethnic populations is also key to advancements in precision medicine and novel diagnostic technologies. Current reference genomic databases, however, are not representative of the global human population, making variant interpretation challenging and uncertain, especially in underrepresented populations such as the North African population. To address this, a study of 391 Egyptian healthy volunteers (EHVols) was initiated as a milestone towards establishing the 1000 Egyptian Genomes project. Keywords: Egyptian reference genome, Egyptian 1000 Genomes, precision medicine, genetic variation, variant interpretation, cardiovascular phenotype, Africa, inherited cardiac conditions, cardiomyopathy.

European Archives of Oto-Rhino-Laryngology, 2019

Purpose Cochlear implantation (CI) has been extended to involve younger age group with higher inc... more Purpose Cochlear implantation (CI) has been extended to involve younger age group with higher incidence of residual hearing which increases the need of minimizing surgical inner ear trauma. Radiological evaluation for electrode position has been studied yet without assessment of inner ear trauma, our objective is radiological evaluation of post cochlear implantation inner ear trauma Material and methods 20 patients with CI for pre lingual SNHL were included in this study. Cone beam CT (CBCT) was used for evaluation of electrode position and assessment of inner ear trauma. A Neuroradiologist and an implant surgeon analyzed the relation of inserted electrode to the intra-cochlear structures, with introduction of novel radiological grading for inner ear trauma. Results The mean major cochlear diameter was 8.9 mm, the mean angular depth of insertion was 406.9944 (SD = 165.0559). Ten patients were with no cochlear trauma (grade 0), three patients were grade 1, two patients were grade 2 and five patients were grade 3 inner ear trauma. Conclusion Radiological evaluation for electrode position should extend to involve assessment of inner ear trauma using relation of the implant to cochlear internal structures which could be performed by CBCT with high resolution and least metallic artifacts.

BJS Open, 2019

Background: End colostomy rates following colorectal resection vary across institutions in high-i... more Background: End colostomy rates following colorectal resection vary across institutions in high-income settings, being influenced by patient, disease, surgeon and system factors. This study aimed to assess global variation in end colostomy rates after left-sided colorectal resection. Methods: This study comprised an analysis of GlobalSurg-1 and-2 international, prospective, observational cohort studies (2014, 2016), including consecutive adult patients undergoing elective or emergency left-sided colorectal resection within discrete 2-week windows. Countries were grouped into high-, middle-and low-income tertiles according to the United Nations Human Development Index (HDI). Factors associated with colostomy formation versus primary anastomosis were explored using a multilevel, multivariable logistic regression model. Results: In total, 1635 patients from 242 hospitals in 57 countries undergoing left-sided colorectal resection were included: 113 (6⋅9 per cent) from low-HDI, 254 (15⋅5 per cent) from middle-HDI and 1268 (77⋅6 per cent) from high-HDI countries. There was a higher proportion of patients with perforated disease (57⋅5, 40⋅9 and 35⋅4 per cent; P < 0⋅001) and subsequent use of end colostomy (52⋅2, 24⋅8 and 18⋅9 per cent; P < 0⋅001) in low-compared with middle-and high-HDI settings. The association with colostomy use in low-HDI settings persisted (odds ratio (OR) 3⋅20, 95 per cent c.i. 1⋅35 to 7⋅57; P = 0⋅008) after risk adjustment for malignant disease (OR 2⋅34, 1⋅65 to 3⋅32; P < 0⋅001), emergency surgery (OR 4⋅08, 2⋅73 to 6⋅10; P < 0⋅001), time to operation at least 48 h (OR 1⋅99, 1⋅28 to 3⋅09; P = 0⋅002) and disease perforation (OR 4⋅00, 2⋅81 to 5⋅69; P < 0⋅001). Conclusion: Global differences existed in the proportion of patients receiving end stomas after left-sided colorectal resection based on income, which went beyond case mix alone.

British Journal of Surgery, 2019

Background The World Health Organization (WHO) Surgical Safety Checklist has fostered safe practi... more Background The World Health Organization (WHO) Surgical Safety Checklist has fostered safe practice for 10 years, yet its place in emergency surgery has not been assessed on a global scale. The aim of this study was to evaluate reported checklist use in emergency settings and examine the relationship with perioperative mortality in patients who had emergency laparotomy. Methods In two multinational cohort studies, adults undergoing emergency laparotomy were compared with those having elective gastrointestinal surgery. Relationships between reported checklist use and mortality were determined using multivariable logistic regression and bootstrapped simulation. Results Of 12 296 patients included from 76 countries, 4843 underwent emergency laparotomy. After adjusting for patient and disease factors, checklist use before emergency laparotomy was more common in countries with a high Human Development Index (HDI) (2455 of 2741, 89·6 per cent) compared with that in countries with a middle...

The Astronomical Journal, 2018

We observed the post-common-envelope eclipsing binary with a white dwarf component, QS Vir, using... more We observed the post-common-envelope eclipsing binary with a white dwarf component, QS Vir, using the 1.88 m telescope of Kotammia Observatory in Egypt. The new observations were analyzed together with all multicolor light curves available online (sampling a period of 25 years), using a full-feature binary system modeling software based on Roche geometry. This is the first time complete photometric modeling was done with most of these data. QS Vir is a detached system, with the red dwarf component underfilling its Roche lobe by a small margin. All light curves feature out-of-eclipse variability that is associated with ellipsoidal variation, mutual irradiation and irregularities in surface brightness of the tidally distorted and magnetically active red dwarf. We tested models with one, two and three dark spots and found that one spot is sufficient to account for the light curve asymmetry in all datasets, although this does not rule out the presence of multiple spots. We also found that a single spotted model cannot fit light curves observed simultaneously in different filters. Instead, each filter requires a different spot configuration. To thoroughly explore the parameter space of spot locations, we devised a grid-search procedure and used it to find consistent solutions. Based on this, we conclude that the dark spot responsible for light curve distortions has been stable for the past 15 years, after a major migration that happened between 1993 and 2002, possibly due to a flip-flop event.

EAS Publications Series, 2013

New BVRI light curves of the eclipsing binary system 1SWASP J160156.04+202821.6 have been obtaine... more New BVRI light curves of the eclipsing binary system 1SWASP J160156.04+202821.6 have been obtained with the 1.88 meter telescope of Kottamia Astronomical Observatory (KAO), Egypt on June, 2013. New twenty times of minima of the system J1601 and new ephemeris have been reduced and derived from the present photometry. A preliminary determination of the geometric and photometric element parameters of the system J1601 has been derived.

Publications of the Astronomical Society of Japan, 2017

We present monitoring campaign observations at optical and near-infrared (NIR) wavelengths for a ... more We present monitoring campaign observations at optical and near-infrared (NIR) wavelengths for a radio-loud active galactic nucleus (AGN) at z = 0.840, SDSS J110006.07+442144.3 (hereafter, J1100+4421), which was identified during a flare phase in late 2014 February. The campaigns consist of three intensive observing runs from the discovery to March, mostly within the scheme of the OISTER collaboration. Optical-NIR light curves and simultaneous spectral energy distributions (SEDs) are obtained. Our measurements show the strongest brightening in 2015 March. We found that the optical-NIR SEDs of J1100+4421 show an almost steady shape despite the large and rapid intranight variability. This constant SED shape is confirmed to extend to ∼5 μm in the observed frame using the archival WISE data. Given the lack of absorption lines and the steep power-law spectrum of α ν ∼ −1.4, where f ν ∝ ν α ν , synchrotron radiation by a relativistic jet with no or small contributions from the host galaxy and the accretion disk seems most plausible as an optical-NIR emission mechanism. The steep optical-NIR spectral shape and the large amplitude of variability are consistent with this object being a low ν peak jet-dominated AGN. In addition, sub-arcsecond resolution optical imaging data taken with Subaru Hyper Suprime-Cam does not show a clear extended component and the spatial scales are significantly smaller than the large extensions detected at radio wavelengths. The optical spectrum of a possible faint companion galaxy does not show any emission lines at the same redshift, and hence a merging hypothesis for this AGN-related activity is not supported by our observations.

Information Bulletin on Variable Stars, 2017

Remark: UCAC4 506-065333 is a DSCT type pulsating variable star in the field of view of V452 Oph.... more Remark: UCAC4 506-065333 is a DSCT type pulsating variable star in the field of view of V452 Oph. It was observed with a 0.25 m Schmidt-Cassegrain telescope (f/10) of the Stazione Astronomica Betelgeuse in Magnago, Italy equipped with a 512×512 pixels Kodak KAF261E CCD cooled to (typ.) −20 • C; 1.6 arcsec per pixel (1×1 binning); 14 ′ ×14 ′ field of view, with V and R C photometric filters. As comparison and check stars were used UCAC4 506-065387 and UCAC4 506-065389. A total of 119 measurements in V band and 94 in R C band were collected; reduction to the standard photometric system was not performed.

Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering, 2016

Energy saving is a major aspect of smart cities, so optimizing highway lighting is essential, as ... more Energy saving is a major aspect of smart cities, so optimizing highway lighting is essential, as it consumes considerable amounts of energy. However, there is a remarkable potential for reducing this consumption through smart lighting techniques. This paper introduces preliminary design and simulation for a smart highway lighting management system based on road occupancy. Wireless Sensors Network (WSN) detects the presence of vehicles along the road, and controls lamps accordingly. The system is simulated and optimized using a realistic probabilistic model for vehicles traffic, taking the advantage of simulation to provide estimation for expected energy saving rates; in contrary to previous works depending only on rough calculations or real-time results after implementation. According to simulation results, the proposed system can save up to 57.4% of power consumption compared to conventional lighting systems.

CNS & Neurological Disorders - Drug Targets, 2017

Parkinson&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp... more Parkinson&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s disease (PD) is the second most common neurological disorder characterized by loss of dopaminergic fibers in the basal ganglia and presence of Lewy bodies. The literature suggests that caffeine play multiple roles in PD. Epidemiological studies showed that caffeine intake was associated with less risk of developing PD, especially in genetically susceptible patients. On the level of Lewy bodies&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#039; formation, caffeine binds to α-synuclein protein inducing conformational changes and preventing their aggregation. On the level of mitochondrial stress, caffeine acts as an antioxidant that reduces oxidative stress in PD and therefore, slows the progression of the disease. On the level of dopamine release, the literature suggests that caffeine increase dopamine release and the number of dopamine receptors in the striatum via A2a receptor antagonism. As an adjuvant treatment, caffeine interacts with antiparkinsonian medications and can alter levodopa pharmacokinetics, reduce dyskinesia, and improve gait in patients with freezing of gait. In this review, we discussed the potential of caffeine as a possible neuroprotective agent and as an add-on therapy for PD.

Egyptian Journal of Anaesthesia, 2016

Objectives: Evaluation of fluid responsiveness of septic shock patients admitted to surgical ICU ... more Objectives: Evaluation of fluid responsiveness of septic shock patients admitted to surgical ICU and the predictability of non-invasive monitoring and estimated lactate/pyruvate (L/P) ratio for survival of these patients. Patients and methods: The study included 58 septic shocked patients admitted and managed at surgical ICU. After non-invasive determination of baseline hemodynamic data and calculation of shock index (SI-0) and Pleth variability index (PVI-0), all patients received intravenous colloid infusion followed 15-min later by non-invasive re-evaluation for SI-15 and PVI-15. Blood samples were obtained for estimation of blood lactate and pyruvate levels at admission (BLL-0 and BPL-0) and 12-h after fluid resuscitation (BLL-12 and BPL-12) and L/P ratio was calculated. All patients were managed according to the Surviving Sepsis Campaign guidelines and followed up for ICU mortality rate (MR). Results: ICU stay MR was 20.7%. Survival showed negative significant correlation with PVI, L/P ratio and BLL, while it showed positive significant correlation with BPL. Receiver Operating Characteristic (ROC) curve analysis defined baseline and persistently low PVI, high BLL and L/P ratio as significant sensitive predictors for MR, while elevated BPL-12 as significant specific predictor for survival. Regression analysis defined persistently elevated L/P ratio as the highly significant specific predictor, while persistently disturbed SI and PVI could predict mortality as screening tests. Odds ratio for mortality at BLL-0 of >2 mmol/L was 0.0321 (95% CI: 0.0037-0.2755), while it was 4.1111 (95% CI: 1.0702-15.792) at BLL-0 >4 mmol/L. Conclusion: After fluid resuscitation and hemodynamic stability, persistently elevated BLL could predict mortality, while elevated BPL could predict survival of septic shock patients. Continuous non-invasive evaluation of fluid responsiveness judged by PVI and SI could provide sensitive

NRIAG Journal of Astronomy and Geophysics, 2013

The CCD observations for the W UMa type binary systems GSC 2362-2866 and GSC 107-596 have been an... more The CCD observations for the W UMa type binary systems GSC 2362-2866 and GSC 107-596 have been analyzed using the Wilson-Devinney Code to determine their photometric orbital and physical parameters. The results show that both systems may be classified as A-subtype of W-UMa eclipsing binary. The mass ratio of GSC 2362-2866 is found to be q = 0.73, with an over-contact degree of f = 0.122%. While the mass ratio of the system GSC 107-596 is found to be q = 0.70 with an over-contact degree of f = 0.166% in V_band and q = 0.69 and f = 0.

Two sets of photometric observations of the system AH Tauri have been analyzed using the latest v... more Two sets of photometric observations of the system AH Tauri have been analyzed using the latest version of the Wilson-Devinney code. The results show that AH Tauri may classified as A-type of W-UMa eclipsing binary. The mass ratio of q = 0.81, an over-contact degree of f = 0.095, and a slightly temperature difference between the two components have been obtained. The asymmetry of its light curve explained by the presence of a dark spot on the massive component. The physical, geometrical, and absolute parameters have been derived and compared with previous work.

Blue and Visual photoelectric light curves have been achieved for the eclipsing binary SW Lac in ... more Blue and Visual photoelectric light curves have been achieved for the eclipsing binary SW Lac in 1995. Nine moments of minimum light were derived. Period of 0.320854 days have been determined as the mean of those derived from blue and visual observations. B and V light curves have been analyzed using W-D code where the system has been viewed through the ellipsoidal model. The system geometrical and physical parameters were determined and compared with those published recently.

A total of 431 photoelectric B and V observations are presented for the short period W UMa system... more A total of 431 photoelectric B and V observations are presented for the short period W UMa system VW Cep. The measurements have been obtained in two successive nights, 27/28 and 28/29 of September 1995, and represent the whole light curve phases. Four times of minimum light, for each filter, were deduced and new periods have been derived as 0.277892 (0.00013) day from the present photometric observations. New light curves have been constructed, investigated and analyzed by using the recent version of W-D code. Table 1: Observational Data of the System VW Cep. Star Name BD No. R. A. 2000 h m s Dec. 2000    V. Mag. Spec. Type No. of obs. B V VW Cep. Comp. Check 75 º 752 75 º 726 73 º 900 20 37 21.5