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Introduction Computed Tomography (CT) scan is a helpful tool to assess the coronary arteries and the great vessels. However, its routine use in the assessment of patients with suspected prosthetic valve dysfunction (PVD) has not been studied thoroughly. Objective To determine the impact of routine cardiac computed tomography angiography (CCTA) on diagnostic and therapeutic decisions in patients with suspected PVD. Methods and results This was a prospective cohort study that was conducted on 50 consecutive patients with suspected PVD who underwent both 64-slice ECG-gated CT and transesophageal echocardiography (TEE). The gold standard was the intraoperative findings. Surgery was performed in forty-six patients. ECG-gated CT showed findings that were not detected by TEE in sixteen patients (32%) namely aortic root abscess, aortic pseudoaneurysm, paravalvular leakage (PVL), sclero-calcific disruption of sutures as cause of PVL, mechanical prosthesis occluder malfunction, an underlying thrombus as cause of malfunction and finally presence of aortic dissection. Furthermore, CTA findings dictated treatment changes in fourteen patients (28%). Conclusion This study demonstrates that ECG-gated CTA has a complementary role to TEE in patients with suspected PVD. CCTA is more accurate in diagnosis of periannular complications (Aortic root abscess and Pseudo-aneurysm) and in delineating their anatomical relation to surrounding cardiac structures. Therefore CCTA can have important role in deciding and planning the method of correction whether surgical or percutaneous and has to be considered after TEE in patients with a high suspicion on PVD.

Introduction and purpose: Computed Tomography (CT) scan has been well addressed to provide a diagnostic information for patients with prosthetic heart valve dysfunction. However, its role in the assessment of patients with prosthetic paravalvular leakage (PVL) has not been studied thoroughly. So, this study was conducted to assess the feasibility, reproducibility, and accuracy of CT for diagnosis of prosthetic PVL using surgical findings as the reference standard. Methods and results: This was a prospective cohort study that was conducted on 26 consecutive patients with suspected prosthetic PVL who underwent both transesophageal echocardiography (TEE) and 64-slice ECG-gated CT. The gold standard was the intraoperative findings. Surgery was performed in twenty-six patients. There was an excellent degree of agreement between CT and intraoperative findings for diagnosis, localization of prosthetic PVL. The perimeter of prosthetic PVL measured by CT was strongly correlated with echocardiographic severity of PVL by TEE (Spearman’s Correlation Coefficient, r = 0.83, P value = 0.0014). Conclusion This study demonstrates that cardiac CT showed comparable diagnostic accuracy to TEE and intraoperative findings for the detection, localization, and assessment of severity of prosthetic PVL. Moreover, CT was shown to be useful in detection of other findings related to prosthetic cardiac valves.

Alpha (B.1.1.7) SARS-COV-2 variant was detected in September 2020 in minks and humans in Denmark and UK. This variant has several mutations in the spike region (S) which could increase the transmissibility of the virus 43-90% over previously circulating variants. The National Center for Disease Control (NCDC) announced on 24th February 2021 a 25% frequency of B.1.1.7 strain in Libya using a reverse-transcriptase quantitative PCR assay. This assay relies on the specific identification of the H69-V70 deletion in S gene which causes its failure of amplification (SGTF). This deletion is not specific for B.1.1.7; but is also characteristic of two other SARS-COV-2 variants. This study aimed to estimate the frequency of B.1.1.7 and identify other variants circulating in Libya in February 2021. We performed whole genome sequencing of 67 positive SARS-COV-2 samples collected on 25th February 2021 in Libya which were also tested by RT-qPCR for SGTF. Our results showed that 55% of samples had mutations specific to B.1.525 strain and only ∼3% of samples belonged to B.1.1.7. These findings suggested that B.1.525 was spreading widely in Libya. The use of such RT-qPCR assay although useful to track some variants, it cannot discriminate between variants with H69-V70 deletion. RT-qPCR assays could be multiplexed to identify multiple variants and screen samples prior to sequencing. We emphasize on the need for providing whole-genome sequencing to the main COVID-19 diagnostic laboratories in Libya as well as establishing international collaboration for building capacity and advancing research in this time of the pandemic.

The current work presents a novel structure of epitaxially grown CuInGaSe2/SiO2 on n-Si substrate using the liquid phase epitaxy (LPE) technique. The electrical and dielectric properties of quaternary alloy CuInGaSe2/SiO2/n-Si were investigated as a Schottky barrier device. The effect of temperature, voltage, and frequency on the electric and dielectric parameters such as dielectric constant ɛ′, dielectric loss ɛ″, dielectric loss tangent tanδ, the real and imaginary part of modulus M′, M″, ac conductivity σac and series resistance Rs were studied by measuring the capacitance–voltage within the temperature range of (303–393 K) and DC voltage range (± 5 V). Both capacitance and conductance were highly affected by varying voltage, frequency, and temperature. Remarkably, capacitance has positive values at high frequencies while it takes negative values at low frequencies. The negative capacitance (NC) was observed for all temperatures. The thickness of the oxide layer was 84 × 10–9 nm. The density of states Nss, Ideality factor, series resistance, shunt resistance, and barrier height were assessed. The impedance spectrum investigation was tailored by suitable equal circuits comprising the contributions of grain and grain boundaries in the conduction mechanism.

Background The aorta is the largest and strongest artery in the body that plays an important role in the control of systemic vascular resistance and heart rate. Aortic diseases contribute to the wide spectrum of arterial diseases that may be diagnosed after a long period of subclinical development. Multidetector computed tomographic scanners (≥ 64 detector rows) for aortic imaging remain one of the most preferred imaging techniques for diagnosis and follow-up of aortic conditions in acute as well as chronic presentations. The aim of this study is to establish a normal reference values for aortic diameters among Egyptian population and to find which of the cardiovascular risk factors could be an independent determinant of the aortic diameters. Results Five hundred and sixteen Egyptian individuals were enrolled in our study, the mean age was 53.5 ± 10.9, and males comprised 61.4% of the study population. Aortic root diameters measured at the annulus, sinus and STJ were 23.09 ± 2.55 mm, 33.75 ± 3.93 mm and 26.13 ± 3.05 mm, respectively. The BSA-indexed diameters were 11.70 ± 1.39, 17.10 ± 2.10 and 13.25 ± 1.65, respectively. The diameter of the tubular part of ascending aorta was 30.97 ± 4.16 mm, and the BSA-indexed diameter was 15.71 ± 2.28. The aortic diameters measured at the level of the pulmonary bifurcation were 24.56 ± 2.95 mm and 23.79 ± 2.96 mm at systolic and diastolic phases, respectively. The BSA-indexed diameters were 12.44 ± 1.52 and 12.05 ± 1.52 at systolic and diastolic phases, respectively. At the diaphragmatic level, the mean diameters were 22.39 ± 2.72 mm and 21.49 ± 2.79 mm at systolic and diastolic phases, respectively. The BSA-indexed diameters were 11.34 ± 1.43 and 10.98 ± 1.48 at systolic and diastolic phases, respectively. Age, gender, BSA, BMI and hypertension were statistically significant independent predictors of ascending and descending aortic diameters. Conclusions Our study established a normal reference value for thoracic aortic diameters among Egyptians using contrast enhanced MSCT aortography. Age, Gender, BSA, BMI and hypertension are the major determinants of aortic diameters.

A total number of 16 Escherichia coli serovars were recovered from different colibacillosis diseased chicken organs. Characterization of the isolates was performed by biochemical and serological tests, biofilm formation, antimicrobial susceptibility assays, detection of virulence and antibiotic resistance genes by PCR. The biofilm formation (at OD595) of all E. coli isolates showed a similar trend. eaeA gene was detected in 3 serovars O2:H6, O26:H11 and O44:H18 while, hly gene was detected in 2 serovars O2:H6 and O144:H21. The gene encoding for stx2 was detected in 2 serovars (O55:H7 and O146:H21) while the gene encoding stx1 was not detected in any serovars. Furthermore, all serovars were carrying the encoding blaTEM. blaSHV and blaCTX were detected in 75% and 18.75% of isolates respectively, while blaOXA-1 was not detected in all serovars. Although all isolates were multi-resistant against most of B-lactams antibiotics, they were susceptible to 20 to 80 mg ml-1 of garlic extract. Finally, we demonstrated that a five-oral administration of garlic extract to baby chicks colonized with E. coli reduces the mortalities and significantly increase the body weight. The efficacy of garlic extract as the antibacterial natural product was sufficient as a bactericidal alternative against the multidrug- resistant E. coli isolates.

Deoxyribonucleic acid (DNA)-templated growth of Bi/Bi2O3 nanowires attached to the Si surface was obtained by electrochemical reduction of Bi(III) at an n-type Si electrode in aqueous Bi(NO3)3/HNO3 at pH 2.5 with calf thymus DNA. The nanowires had a mean diameter of 5 nm and a range of lengths from 1.4 μm to 6.1 μm. The composition and structure of the wires were determined by atomic force microscopy, Fourier transform infrared spectroscopy, Raman spectroscopy and X-ray photoemission spectroscopy. The dominant component of the material is Bi2O3 owing to the rapid re-oxidation of nanoscale Bi in the presence of air and water. Our method has the potential to construct complex architectures of Bi/Bi2O3 nanostrucures on high quality Si substrates.

Toxoplasmosis is one of the most common diseases prevalent in the world, caused by a coccidian parasite Toxoplasma gondii which infects humans, animals and birds. Poultry consider reliable human source of food in addition it is considered an intermediate host in transmission of the disease to humans. Trails of isolation of local T. gondii chicken strain through bioassay of the suspected infected chicken tissues in mice was carried out and the isolated strain was confirmed as being T. gondii using Polymerase Chain Reaction (PCR). Seroprevalence of antibodies against T. gondii in chicken sera in six Egyptian governorates were conducted by enzyme linked immune-sorbent assay (ELISA) using the isolated chicken strain antigen. Moreover, comparison between the prevalence rates in different regions of the Egyptian governorates were been estimated. Isolation of local T. gondii chicken strain was accomplished from chicken tissues and confirmed by PCR technique. The total prevalence rate was 68.8% comprised of 59.5, 82.3, 67.1, 62.2, 75 and 50% in El Sharkia, El Gharbia, Kafr El sheikh, Cairo, Quena and Sohag governorates, respectively. The prevalence rates were higher among Free Range (FR) (69.5%) than commercial farm Chickens (C) (68.5%); while, the prevalence rate was less in Upper Egypt than Lower Egypt governorates and Cairo. This study is the first was used antigen from locally isolated T. gondii chicken strain for the diagnosis of chicken toxoplasmosis. The higher seroprevalence particularly in free range chickens (house-reared) refers to the public health importance of chickens as source of zoonotic toxoplasmosis to human.