Despite efforts to contain and manage the SARS-CoV-2 outbreak which was declared a public health emergency of international concern in January 2020 by the World Health Organization (WHO), the COVID-19 pandemic still remains a major global challenge. Patients who display the classical symptoms of the infection are easily identified, tested, isolated and monitored. However, many cases of infected asymptomatic patients have been documented. These patients are not easily identified even though many evidences suggest that they can spread the virus to others. How and why these COVID-19 asymptomatic presentations occur remain unclear. The many theories and views are conjectural, and supporting evidences are still needed. In this review, we described the trend in SARS-CoV-2 viral shedding and susceptibility, providing perspectives on gender differences and asymptomatic patients. We further discussed how genetics, gender, viral inoculum, and pre-existing immunity may influence asymptomatic presentations in COVID-19 infections. We hope that this article improves our understanding of asymptomatic SAR-CoV-2 infection and it sheds light on some salient areas that should be considered as the search for a potent vaccine continues.
The growing population and the rising standard of living in cities as well as the increased commercial, industrial and agricultural activities around the world led to
massive production of waste containing different materials and one of them is the municipal solid waste (MSW), so there is a major problem facing the cities around the world about the waste, how to collect, transfer it and how to discard it. Because the accumulation of wastes, whether in the city alleys or in its squares and especially in its residential areas affect the health of their populations besides this situation will be a major indication of the deteriorating quality of life in the city, as hygiene considered a fundamental criterion for the city beauty as well
Lipopolysaccharide (LPS) of Campylobacter coli was extracted by using
digestive enzyme and hot phenol method. The effect of LPS on lymphocyte
transform was studies by lymphocyte transformation index for twenty blood samples
were collected from apparently healthy control.
The results were showed significant differences (P< 0.05) between samples which
treatrd with phytohemagglutnin PHA (66.1 ± 0.6) and the samples which treated
with LPS of C. coli (74.2 ± 0.8) when compared with control, this lead to suggest
that the LPS extracted from C. coli may play a role as a mitogen to transformed
lymphocytes.
In this research, we studied the effect of (β-rays) on the optical properties of pure (PMMA) films prepared by using casting technique, and the optical properties for these films was studied before and after irradiation by recording the Absorption and Transmission spectra for a range of wavelength range (190-1100) nm. and then the absorption and Transmission and the reflectivity, extinction coefficient, refractive index, and real and imaginary parts of dielectric constant was studied
Construction joints are stopping places in the process of placing concrete, and they are required because in many structures it is impractical to place concrete in one continuous operation. The amount of concrete that can be placed at one time is governed by the batching and mixing capacity and by the strength of the formwork. A good construction joint should provide adequate flexural and shear continuity through the interface.
In this study, the effect of location of construction joints on the performance of reinforced concrete structural elements is experimentally investigated.
Nineteen beam specimens with dimensions of 200×200×950 mm were tested. The variables investigated are the location of the construction joints
... Show MoreFacial emotion recognition finds many real applications in the daily life like human robot interaction, eLearning, healthcare, customer services etc. The task of facial emotion recognition is not easy due to the difficulty in determining the effective feature set that can recognize the emotion conveyed within the facial expression accurately. Graph mining techniques are exploited in this paper to solve facial emotion recognition problem. After determining positions of facial landmarks in face region, twelve different graphs are constructed using four facial components to serve as a source for sub-graphs mining stage using gSpan algorithm. In each group, the discriminative set of sub-graphs are selected and fed to Deep Belief Network (DBN) f
... Show MoreFifteen blood samples were collected from healthy males and females (6 males &
9 females), average age (21-34 years) in heparinized sterile tubes. The extracellular
protease was extracted from a clinical isolate of Serratia marcescens that was
isolated from a patient suffering from urinary tract infection taken from the Central
Health Laboratory. The extracted protease was purified partial by two steps,
precipitation with 30-55% saturation of ammonium sulfate following with dialysis
and ion exchange chromatography DEAE-cellulose. The protease concentration was
0.15 mg/ml. Two concentration 0.258g/ml and 0.58/ml of protease were prepared
and applied in current study. Lymphocyte transformation test using whole b
Localization is an essential demand in wireless sensor networks (WSNs). It relies on several types of measurements. This paper focuses on positioning in 3-D space using time-of-arrival- (TOA-) based distance measurements between the target node and a number of anchor nodes. Central localization is assumed and either RF, acoustic or UWB signals are used for distance measurements. This problem is treated by using iterative gradient descent (GD), and an iterative GD-based algorithm for localization of moving sensors in a WSN has been proposed. To localize a node in 3-D space, at least four anchors are needed. In this work, however, five anchors are used to get better accuracy. In GD localization of a moving sensor, the algo
... Show MoreTwo hundred fifty mid-stream urine specimens were collected from Baqubah Teaching Hospital and Al-Batool Teaching Hospital from patients with urinary tract infections (UTI). Of these investigated urine specimens, 66 (26.4%) specimens showed positive growth culture of Gram-negative bacteria. From these, Escherichia coli was the most prevalent bacteria of the examined culture (41, 62.12%). Additionally, the cup assay was used to determine colicin producers while the most efficient colicin producers were estimated by the formation of larger inhibition zone. Approximately half of the investigated E. coli isolates (20, 49 %) was colicin producers. Colicins was extracted after induction by mitomycin-C showed a concentration o
... Show MoreNanoparticles are a special group of materials with unique features and extensive applications in diverse fields. The use of nanoparticles of some metals is a viable solution to stop infectious diseases due to the antimicrobial properties of these nanoparticles. The present work demonstrates the effect of silver nanoparticles (AgNPs) on the antibacterial activity of four different antibiotics (amoxicillin, ceftriaxone, chloramphenicol, and penicillin) against eleven Gram-positive and Gram-negative isolates. Disk diffusion method was used to determine the antibacterial activity of various classes of antibiotics in the absence and presence of sub-inhibitory silver nanoparticles of concentration (80 microgram/ml). A synergistic effect was o
... Show MoreThe adsorption of zirconium, on manganese dioxide from nitric
acid solutions has been studied as a function of shaking time, concentration of electrolytes, concentration of adsorbate and temperature effects (25- 90°C).
Four hours of shaking was appropriate to ensure that the
adsorption plateau was reached and the adsorption of zirconium decrease with an increase in nitric acid concentration. The limiting adsorption capacities at 3 molar nitric acid was 0.2 Zr per mole of Mn02. Working at elevated temperature was in favour
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