99 research outputs found

    On the derivatives of a family of analytic functions

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    For β<1\beta< 1, n = 0, 1, 2, . . ., and −π<α≤π-\pi <\alpha\leq\pi, we let Mn(α,β)M_n(\alpha,\beta) denote the family of functions f(z)=z+…f(z) = z +\ldots that are analytic in the unit disk and satisfy there the condition Re{(Dnf)′+1+eiα2(n+1)z(Dnf)′′}>βRe\{(D^n f)'+\frac{1+e^{i\alpha}}{2(n+1)}z(D^n f)''\}>\beta, where Dnf(z)D^n f(z) is the Hadamard product or convolution of f with z/(1−z)n+1z/(1 − z){n+1}. We prove the inclusion relations Mn+1(α,β)⊂Mn(α,βM_{n+1}(\alpha,\beta) \subset M_n(\alpha,\beta, and Mn(α,β)<Mn(π,β),β<1M_n(\alpha,\beta) < M_n(\pi,\beta), \beta < 1. Extreme points, as well as integral and convolution characterizations, are found. This leads to coefficient bounds and other extremal properties. The special cases M0(α,0)≡LαM_0(\alpha,0)\equiv \mathcal{L}_\alpha, Mn(π,β)≡Mn(β)M_n(\pi,\beta)\equiv M_n(\beta) have previously been studied [16], [1]

    On Some Subclasses of Harmonic Functions Defined by Fractional Calculus

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    The purpose of this paper is to study subclasses of normalized harmonic functions with positive real part using fractional derivative. Sharp estimates for coefficients and distortion theorems are given

    Endobronchial Tuberculosis Simulating Lung Cancer and Healing without Bronchial Stenosis

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    Endobroncheal tuberculosis is defined as tuberculous infection of the tracheobronchial tree with microbial and histopathological evidence. The disease is usually mistaken for other lung diseases including lung cancer. Bronchial stenosis is a common complication of this type of tuberculosis despite the use of effective anti-tuberculous chemotherapy. We are presenting a case of endobronchial tuberculosis that simulated lung cancer and healed without residual bronchial stenosis

    Epidemiology of respiratory infections among adults in Qatar (2012-2017).

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    Limited data is available about the etiology of influenza like illnesses (ILIs) in Qatar. This study aimed at providing preliminary estimates of influenza and other respiratory infections circulating among adults in Qatar. We retrospectively collected data of about 44,000 patients who visited Hamad General Hospital clinics, sentinel sites, and all primary healthcare centers in Qatar between 2012 and 2017. All samples were tested for influenza viruses, whereas about 38,000 samples were tested for influenza and a panel of respiratory viruses using Fast Track Diagnostics (FTD) RT-PCR kit. Among all ILIs cases, 20,278 (46.5%) tested positive for at least one respiratory pathogen. Influenza virus was predominating (22.6%), followed by human rhinoviruses (HRVs) (9.5%), and human coronaviruses (HCoVs) (5%). A detection rate of 2-3% was recorded for mycoplasma pneumonia, adenoviruses, human parainfluenza viruses (HPIVs), respiratory syncytial virus (RSV), and human metapneumovirus (HMPV). ILIs cases were reported throughout the year, however, influenza, RSV, and HMPV exhibited strong seasonal peaks in the winter, while HRVs circulated more during fall and spring. Elderly (>50 years) had the lowest rates of influenza A (13.9%) and B (4.2%), while presenting the highest rates of RSV (3.4%) and HMPV (3.3%). While males had higher rates of HRVs (11.9%), enteroviruses (1.1%) and MERS CoV (0.2%), females had higher proportions of influenza (26.3%), HPIVs (3.2%) and RSV (3.6%) infections. This report provides a comprehensive insight about the epidemiology of ILIs among adults in the Qatar, as a representative of Gulf States. These results would help in improvement and optimization of diagnostic procedures, as well as control and prevention of the respiratory infections.This study was supported by funds from Hamad Medical Corporation (grant # 16335/16) and Qatar University (grant # QUCG-BRC-2018/2019-1)

    Within-Host Diversity of SARS-CoV-2 in COVID-19 Patients With Variable Disease Severities.

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    The ongoing pandemic of SARS-COV-2 has already infected more than eight million people worldwide. The majority of COVID-19 patients either are asymptomatic or have mild symptoms. Yet, about 15% of the cases experience severe complications and require intensive care. Factors determining disease severity are not yet fully characterized. Here, we investigated the within-host virus diversity in COVID-19 patients with different clinical manifestations. We compared SARS-COV-2 genetic diversity in 19 mild and 27 severe cases. Viral RNA was extracted from nasopharyngeal samples and sequenced using the Illumina MiSeq platform. This was followed by deep-sequencing analyses of SARS-CoV-2 genomes at both consensus and sub-consensus sequence levels. Consensus sequences of all viruses were very similar, showing more than 99.8% sequence identity regardless of the disease severity. However, the sub-consensus analysis revealed significant differences in within-host diversity between mild and severe cases. Patients with severe symptoms exhibited a significantly (-value 0.001) higher number of variants in coding and non-coding regions compared to mild cases. Analysis also revealed higher prevalence of some variants among severe cases. Most importantly, severe cases exhibited significantly higher within-host diversity (mean = 13) compared to mild cases (mean = 6). Further, higher within-host diversity was observed in patients above the age of 60 compared to the younger age group. These observations provided evidence that within-host diversity might play a role in the development of severe disease outcomes in COVID-19 patients; however, further investigations are required to elucidate this association.This work was supported by Qatar University under internal grant (QUCG-BRC-20/21-1) and Qatar National Research Fund grant under grant (RRC-2-039)

    Performance evaluation of five ELISA kits for detecting anti-SARS-COV-2 IgG antibodies

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    Objectives: To evaluate and compare the performances of five commercial ELISA assays (EDI, AnshLabs, Dia.Pro, NovaTec, and Lionex) for detecting anti-SARS-CoV-2 IgG. / Methods: Seventy negative control samples (collected before the COVID-19 pandemic) and samples from 101 RT-PCR-confirmed SARS-CoV-2 patients (collected at different time points from symptom onset: ≤7, 8–14 and >14 days) were used to compare the sensitivity, specificity, agreement, and positive and negative predictive values of each assay with RT-PCR. A concordance assessment between the five assays was also conducted. Cross-reactivity with other HCoV, non-HCoV respiratory viruses, non-respiratory viruses, and nuclear antigens was investigated. / Results: Lionex showed the highest specificity (98.6%; 95% CI 92.3–99.8), followed by EDI and Dia.Pro (97.1%; 95% CI 90.2–99.2), NovaTec (85.7%; 95% CI 75.7–92.1), then AnshLabs (75.7%; 95% CI 64.5–84.2). All ELISA kits cross-reacted with one anti-MERS IgG-positive sample, except Lionex. The sensitivity was low during the early stages of the disease but improved over time. After 14 days from symptom onset, Lionex and NovaTec showed the highest sensitivity at 87.9% (95% CI 72.7–95.2) and 86.4% (95% CI 78.5–91.7), respectively. The agreement with RT-PCR results based on Cohen's kappa was as follows: Lionex (0.89) > NovaTec (0.70) > Dia.Pro (0.69) > AnshLabs (0.63) > EDI (0.55). / Conclusion: The Lionex and NovaLisa IgG ELISA kits, demonstrated the best overall performance

    Molecular epidemiology of influenza, RSV, and other respiratory infections among children in Qatar: A six years report (2012–2017)

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    Background: Studies on the etiology of respiratory infections among children in Qatar and surrounding countries are limited. Objectives: To describe the prevalence and seasonality of RSV, influenza, and other respiratory pathogens among children in Qatar. Methods: We retrospectively collected and analyzed data of 33,404 children (<15 years) presented with influenza-like illness from 2012 to 2017. Results: At least one respiratory pathogen was detected in 26,138 (78%) of patients. Together, human rhinoviruses (HRV), respiratory syncytial virus (RSV), and influenza viruses comprised nearly two-thirds of all cases, affecting 24%, 19.7%, and 18.5%, respectively. A prevalence of 5-10% was recorded for adenovirus, parainfluenza viruses (PIVs), human bocavirus (HboV), and human coronaviruses (HCoVs). Human metapneumovirus (HMPV), enteroviruses, M. pneumonia, and parechovirus had prevalences below 5%. While RSV, influenza, and HMPV exhibited strong seasonal activity in the winter, HRV was active during low RSV and influenza circulation. The burden of RSV exceeds that of influenza among young age groups, whereas influenza correlated positively with age. Further, HRV, adenovirus, influenza, and RSV infection rates varied significantly between male and females. Conclusion: This comprehensive multi-year study provides insights into the etiology of ILI among children in Qatar, which represents the Gulf region. Our results reinforce the significance of active surveillance of respiratory pathogens to improve infection prevention and control strategies, particularly among children

    Association between waterpipe smoking and obesity: Population-based study in Qatar

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    Introduction: Over the past decade obesity prevalence has been increasing rapidly in the Gulf region (GR) including Qatar, becoming one of the major health issues in the region. Concomitantly, waterpipe (WP) smoking is increasing worldwide especially in the GR, and although the effect of cigarette smoking on body weight is well-established, studies indicating an association between WP smoking and obesity are scarce. Thus, we explored the association between WP smoking and obesity in comparison with cigarette smokers and healthy population in Qatar. Methods: We performed a cross-sectional study using data from Qatar Biobank and analyzed anthropometric measurements among 879 adults (aged 18–65 years) that included WP smokers, cigarette smokers, dual smokers and never smokers. Body composition was measured using bioelectrical impedance analysis and reported as lean mass, fat mass, and body fat percentage. Results: Overall, 12% (n=108) were WP smokers, 22% (n=196) were cigarette smokers, 9% (n=77) smoked both WP and cigarettes and 57% (n=498) were never smokers. Age, sex, history of diabetes, and hypertension, in addition to nationality were considered as confounding factors. Our analysis revealed that WP smokers had a significantly higher BMI (kg/m2) and fat mass when compared with cigarette smokers (p<0.05). Moreover, compared to cigarette smoking, WP smoking had a higher significant effect on BMI (β=3.8, SE=0.38; and β=5.5, SE=0.46; respectively), and fat mass (β=5.1, SE=0.79; and β=9.0, SE=0.97; respectively). However, WP users were similar to never-smokers in terms of body fat percent. Conclusions: Our data indicate that compared to never smokers, daily WP users have higher BMI and fat mass, and are likely to be obese.This work is supported by the College of Medicine and Health Cluster of Qatar University. The funder had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.Scopu

    Middle East respiratory syndrome coronavirus in dromedary camels: An outbreak investigation

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    Background: Middle East respiratory syndrome coronavirus (MERS-CoV) causes severe lower respiratory tract infection in people. Previous studies suggested dromedary camels were a reservoir for this virus. We tested for the presence of MERS-CoV in dromedary camels from a farm in Qatar linked to two human cases of the infection in October, 2013. Methods: We took nose swabs, rectal swabs, and blood samples from all camels on the Qatari farm. We tested swabs with RT-PCR, with amplification targeting the E gene (upE), nucleocapsid (N) gene, and open reading frame (ORF) 1a. PCR positive samples were tested by different MERS-CoV specific PCRs and obtained sequences were used for phylogentic analysis together with sequences from the linked human cases and other human cases. We tested serum samples from the camels for IgG immunofluorescence assay, protein microarray, and virus neutralisation assay. Findings: We obtained samples from 14 camels on Oct 17, 2013. We detected MERS-CoV in nose swabs from three camels by three independent RT-PCRs and sequencing. The nucleotide sequence of an ORF1a fragment (940 nucleotides) and a 4·2 kb concatenated fragment were very similar to the MERS-CoV from two human cases on the same farm and a MERS-CoV isolate from Hafr-Al-Batin. Eight additional camel nose swabs were positive on one or more RT-PCRs, but could not be confirmed by sequencing. All camels had MERS-CoV spike-binding antibodies that correlated well with the presence of neutralising antibodies to MERS-CoV. Interpretation: Our study provides virological confirmation of MERS-CoV in camels and suggests a recent outbreak affecting both human beings and camels. We cannot conclude whether the people on the farm were infected by the camels or vice versa, or if a third source was responsible. Funding: European Union projects EMPERIE (contract number 223498), ANTIGONE (contract number 278976), and the VIRGO consortium
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