22 research outputs found

    KINETIC ANALYSIS OF AROMATIZATION OF N-HEXANEON PLATINUM/ALUMINA CATALYST USING THE TIKHONOV REGULARIZATION TECHNIQUE

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    Tikhonov regularization, which is a new technique for converting time-concentration data into concentration-reaction rate data, was applied to the kinetic analysis of n-hexane aromatization on Platinum/Alumina Catalyst.The technique was used for the conversion of the experimental concentration-time data to rate-concentration data. Due to the ill-posed nature of the problem of obtaining of reaction rates from experimental data, conventional methods will lead to noise amplification of the experimental data. Hence, Tikhonov regularization technique is preferably employed because it is entirely independent of reaction rate models and it also manages to minimize noise amplification, thus, leading to more reliable results. The kinetic parameters obtained by the application of the Nelder-Mead simplex optimization technique to formulated mechanistic models was used to discriminate among rival kinetic models based upon physicochemical criteria and thermodynamic tests to give the rate of conversion of adsorbed hexene-1 to adsorbed methylcyclopentane when hydrogen is adsorbed as a bi-molecular specie as the rate determining ste

    KINETIC ANALYSIS OF AROMATIZATION OF N-HEXANEON PLATINUM/ALUMINA CATALYST USING THE TIKHONOV REGULARIZATION TECHNIQUE

    Get PDF
    Tikhonov regularization, which is a new technique for converting time-concentration data into concentrationreaction rate data, was applied to the kinetic analysis of n-hexane aromatization on Platinum/Alumina Catalyst.The technique was used for the conversion of the experimental concentration-time data to rate-concentration data. Due to the ill-posed nature of the problem of obtaining of reaction rates from experimental data, conventional methods will lead to noise amplification of the experimental data. Hence, Tikhonov regularization technique is preferably employed because it is entirely independent of reaction rate models and it also manages to minimize noise amplification, thus, leading to more reliable results. The kinetic parameters obtained by the application of the Nelder-Mead simplex optimization technique to formulated mechanistic models was used to discriminate among rival kinetic models based upon physicochemical criteria and thermodynamic tests to give the rate of conversion of adsorbed hexene-1 to adsorbed methylcyclopentane when hydrogen is adsorbed as a bi-molecular specie as the rate determining step

    Seroprevalence of camel brucellosis in Qatar

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    Brucellosis is a significant zoonotic disease and one of the most common neglected diseases worldwide. It can infect a wide range of domestic and wild animal species. Infected animals are usually culled, causing substantial economic losses to animal owners and the country’s economy in general. The disease is endemic among cattle, sheep, and goats in many countries around the Middle East and prevalent in most Gulf Cooperation Council countries, comprising a significant public health risk in the region. This study investigated the seroprevalence of brucellosis among camels in Qatar. Two hundred and forty-eight samples were collected from dromedary camels from 28 farms across the entire country. Each sample was tested for Brucella antibodies with both Rose Bengal and competitive enzyme-linked immunosorbent assay. Only samples that tested positive by both tests were considered seropositive for brucellosis. The overall prevalence was (20.6%, 95% CI, 15.7–26.1). The association between sex and seropositivity was slightly significant (Χ2 = 4.32, P = 0.04), with higher seroprevalence in females. Camels below breeding age (i.e., < 4 years old) showed decreased seropositivity (3.4%, 95% CI, 0.1–17.8), compared to (22.8%, 95% CI, 17.4–29.0) seropositivity in camels ≥ 4 years of age, with a significant association between age groups and seropositivity (P = 0.02). Our results indicate that the seroprevalence of brucellosis in Qatar’s camels is alarming, mandating more efforts to control the disease. The findings of this study will aid in selecting better effective measures to control camel brucellosis in Qatar. Further studies need to be conducted on Brucella infection among camels to determine the predisposing risk factors and the steps that should be followed to control brucellosis.Open Access funding provided by the Qatar National Library. This work was supported by Qatar University grant number QUCG-BRC-20/21–2 and high potential projects program QPH3P-BRC-2021–604 to Nahla O. Eltai

    QCovSML: A reliable COVID-19 detection system using CBC biomarkers by a stacking machine learning model

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    The reverse transcription-polymerase chain reaction (RT-PCR) test is considered the current gold standard for the detection of coronavirus disease (COVID-19), although it suffers from some shortcomings, namely comparatively longer turnaround time, higher false-negative rates around 20–25%, and higher cost equipment. Therefore, finding an efficient, robust, accurate, and widely available, and accessible alternative to RT-PCR for COVID-19 diagnosis is a matter of utmost importance. This study proposes a complete blood count (CBC) biomarkers-based COVID-19 detection system using a stacking machine learning (SML) model, which could be a fast and less expensive alternative. This study used seven different publicly available datasets, where the largest one consisting of fifteen CBC biomarkers collected from 1624 patients (52% COVID-19 positive) admitted at San Raphael Hospital, Italy from February to May 2020 was used to train and validate the proposed model. White blood cell count, monocytes (%), lymphocyte (%), and age parameters collected from the patients during hospital admission were found to be important biomarkers for COVID-19 disease prediction using five different feature selection techniques. Our stacking model produced the best performance with weighted precision, sensitivity, specificity, overall accuracy, and F1-score of 91.44%, 91.44%, 91.44%, 91.45%, and 91.45%, respectively. The stacking machine learning model improved the performance in comparison to other state-of-the-art machine learning classifiers. Finally, a nomogram-based scoring system (QCovSML) was constructed using this stacking approach to predict the COVID-19 patients. The cut-off value of the QCovSML system for classifying COVID-19 and Non-COVID patients was 4.8. Six datasets from three different countries were used to externally validate the proposed model to evaluate its generalizability and robustness. The nomogram demonstrated good calibration and discrimination with the area under the curve (AUC) of 0.961 for the internal cohort and average AUC of 0.967 for all external validation cohort, respectively. The external validation shows an average weighted precision, sensitivity, F1-score, specificity, and overall accuracy of 92.02%, 95.59%, 93.73%, 90.54%, and 93.34%, respectively

    Finishing the euchromatic sequence of the human genome

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    The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

    Assessment of the role of serum 25-hydroxy vitamin D level on coronary heart disease risk with stratification among patients with type 2 diabetes mellitus

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    We investigated the role of vitamin D on glycemic regulation and cardiac complications in patients with type 2 diabetes mellitus (T2DM). A total of 1139 patients (49.3% males vs 50.7% females) were included. Information on sociodemographic lifestyle, family history, blood pressure (BP), and coronary heart disease (CHD) complications was collected. Significant differences were found between males and females regarding age-groups (P= .002), body mass index (BMI;P= .008), physical activity (P= .010), sheesha smoking (P= .016), cigarette smoking (P= .002), hypertension (P= .050), metabolic syndrome (P= .026), and CHD (P= .020). There were significant differences between vitamin D deficiency, insufficiency, and sufficiency in relation to age-group (P= .002), income (P= .002), waist circumference (P= .002), hip circumference (P= .028), waist-hip ratio (P= .002), and BMI (P= .002). Further, mean values of hemoglobin, magnesium, creatinine, hemoglobin A(1c)(HbA(1c)), total cholesterol, uric acid, and diastolic BP were significantly higher among patients with vitamin D deficiency compared with those with insufficiency and sufficiency. Multiple logistic regression analysis revealed that 25-hydroxy vitamin D, 25(OH)D, HbA(1c), waist circumference, uric acid, duration of T2DM, total cholesterol, systolic and diastolic BP, and BMI were strong predictor risk factors for CHD among patients with T2DM. The present study supports that 25(OH)D may have a direct effect on CHD and on its risk factors.Qatar Diabetes AssociationIstanbul Medipol UniversityQatar Foundatio

    Seroprevalence of small ruminant brucellosis in the state of Qatar

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    Background: Brucellosis is one of the most important zoonotic diseases worldwide, with a significant economic and health burden. The disease is endemic in many regions around the world. Data regarding the disease in the Arabic Gulf region is scarce, and a limited number of studies have been conducted in Qatar. This study is the first to investigate the seroprevalence of small ruminant brucellosis in the state of Qatar. Methods: The country was divided into three zones based on animal population (high, medium and low). A total of 494 blood samples from 57 small ruminant flocks were randomly collected from the three zones. Rose Bengal and competitive enzyme-linked immunosorbent assay were used to investigate the apparent and true seroprevalence at both the animal and flock levels. A regression model was used to investigate the potential risk factors, including geographic zone, sex and age. Results: At the animal level, the overall (sheep and goat) apparent and true seroprevalence were 9.6% (95% confidence interval [95% CI]: 7.3–12.5) and 8.4% (95% CI: 5.9–11.5), respectively. In sheep, the apparent seroprevalence was 16.7% (95% CI: 12.5–21.8), and the true seroprevalence was 16.1% (95% CI: 11.6–21.7), whereas in goats, the apparent seroprevalence was 2.4% (95% CI: 1.1–5.2), and the true seroprevalence was 0.7% (95% CI: −0.7 to 3.7). At the flock level, overall, apparent sheep and goat seroprevalence were 19.3% (95% CI: 11.1–31.3), 30.0% (95% CI: 16.1–49.8) and 7.4% (95% CI: 2.1–23.4) and true seroprevalence was 18.9% (95% CI: 10.1–31.9), 30.5% (95% CI: 16.1–49.8) and 6.1% (95% CI: 0.3–23.3) respectively. Univariable regression analysis revealed age as the only significant risk factor in the sampled population. Conclusions: Brucella appears to be endemic to small ruminants in Qatar. The findings of this study provide baseline data regarding small ruminant brucellosis in Qatar and will aid in plans to control and eradicate the disease.This work was supported by the Qatar University, Grant Number: QUCG‐BRC‐20/21‐2. Open access funding was provided by the Qatar National Library
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