792 research outputs found

    Study of the Impact of LPG Composition on the Blowoff and Flashback Limits of a Premixed Flame in a Swirl Burner

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    Liquefied petroleum gas (LPG) is considered one of the gases widely used in many industrial and residential sectors. Still, due to its different compositions, mainly propane (C3H8) and butane (C4H10), it can have other combustion characteristics. This paper aims to conduct an experimental analysis to study the impact of LPG composition on the stability map (limits of blowoff and flashback) of the premixed flame in a tangential swirl burner. Four LPG mixtures were used with different proportions of ethane (C2H6), propane (C3H8), butane (C4H10), and pentane (C5H12). Three burner nozzles at diameters of 20, 25, and 30 mm have been used, which gave three swirl numbers of 0.918, 1.148, and 1.377, respectively. The results indicate that increasing the swirl number (S) from 0.918 to 1.377 for all LPG mixtures accelerated the flashback propensity (getting worse) while the blowoff resistance improved; thus, a rising S gave a better stability map. As for the effect of the LPG composition, it was found that the maximum flame temperature was for the LPG mixture containing high percentages of butane (C4H10), while the lowest was for the mixture containing fewer percentages of butane. Changing the LPG composition had an apparent effect on the flashback limits and a slight effect on the blowoff limits; it was found that mixtures containing high percentages of butane increased flame speeds and increased the flashback propensity. Compared to LPG mixtures, the flame stability map was widest for LPG mixtures containing lower percentages of butane. Therefore, LPG with propane (C3H8) proportions higher than butane (C4H10) reduces flame temperature, flame speeds, and flashback propensity, thus improving the stability map

    Experimental Study of Breast Cancer Detection Using UWB Imaging

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    Breast cancer detection using UWB imaging is presented in this paper. The study is performed experimentally. Homogeneous breast phantom is constructed using pure petroleum jelly. The tumor is modeled using mixture of water and wheat flour. The breast fatty tissue and tumor tissue are put in breast shaped glass which mimics the skin. The dielectric properties values are comparable to previous study. Neural Network (NN) was trained and tested using feature vector which is prepared by performing discrete cosine transform (DCT) of the received UWB signals. Very encouraging results were obtained. Up to 100 % tumor existence detection was achieved. Tumor size and location detection rate were 91.3% and 95.6% respectively

    The Effect of Solvent-Modification on the Physicochemical Properties of ZnO Nanoparticles Synthesized by Sol-Gel Method

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    This study investigated the solvent effect on the synthesis of Zinc Oxide (ZnO) nanoparticle using sol-gel method. Zinc acetate dihydrate and oxalic acid were used as a chemical precursor for the synthesis of the ZnO nanoparticle considering the effects of various solvents. The effect of using water, propanol, or ethanol as solvent during the synthesis were examined. The resultant gel in the aqueous and organic moderate solvent was thermally cracked into ZnO nanoparticles at 450 °C under atmospheric pressure. The results showed that the solvent type has a significant effect on the morphology and particles size of the ZnO nanoparticles synthesized. Atomic Force Microscopy (AFM) was used to investigate the microstructure of the nanoparticles. The crystalline and chemical structure of the prepared ZnO nanoparticle were studied by X-ray diffraction (XRD) and Fourier Transform Infrared spectroscopy (FTIR). The average diameter of nano-size particles obtained for ethanol, propanol and water are 79.55 nm, 83.86 nm and 85.59 nm, respectively. ZnO particles showed higher degree of crystalline in water compared to other solvents under current investigation. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

    Natural Polysaccharides as Preventive and Therapeutic Horizon for Neurodegenerative Diseases

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    Neurodegenerative diseases are a serious and widespread global public health burden amongst aging populations. The total estimated worldwide global cost of dementia was US818billionin2015andhasbeenprojectedtoriseto2trillionUS818 billion in 2015 and has been projected to rise to 2 trillion US by 2030. While advances have been made to understand different neurodegenerative disease mechanisms, effective therapeutic strategies do not generally exist. Several drugs have been proposed in the last two decades for the treatment of different types of neurodegenerative diseases, with little therapeutic benefit, and often with severe adverse and side effects. Thus, the search for novel drugs with higher efficacy and fewer drawbacks is an ongoing challenge in the treatment of neurodegenerative disease. Several natural compounds including polysaccharides have demonstrated neuroprotective and even therapeutic effects. Natural polysaccharides are widely distributed in plants, animals, algae, bacterial and fungal species, and have received considerable attention for their wide-ranging bioactivity, including their antioxidant, anti-neuroinflammatory, anticholinesterase and anti-amyloidogenic effects. In this review, we summarize different mechanisms involved in neurodegenerative diseases and the neuroprotective effects of natural polysaccharides, highlighting their potential role in the prevention and therapy of neurodegenerative disease

    CFD Simulations and Experimental Observation for Air-Water Two-phase Flow in a Vertical Pipe

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    Air-water two-phase flow development in a vertical pipe has been investigated through service of experiments and simulations in this research. Differential Pressure Transducers (DPTs) and Wire Mesh sensors (WMSs) are used to monitor the two-phase flow in a vertical pipe of 67 mm inlet diameter and 7000 mm length. Computational Fluid Dynamic (CFD) is used to evaluate the experiments of the air-water flow in the vertical pipe using a volume of fluid (VOF) model. The operating conditions cover a range of inlet air superficial velocities from 0.05 to 5 m/s. The inlet water superficial velocity remains constant at 0.2m/s and 0.4 m/s for all experiments. The results show that the bubbly flow is noted at low superficial velocities of gas, slug flow is observed at the moderate flow rates of gas, while the churn flow pattern is observed at high rates of gas. There is no significant effect when the Usl changed from 0.2 m/s to 0.4 m/s on the vertical flow lines. Pressure drop is recorded and compared with the CFD simulations. The CFD results are over estimation compared with the experimental pressured drop with maximum absolute error of 21% at Usl of 0.2 m/s and 25% at Usl 0.4 m/s

    Knowledge, attitudes, and positions of religious leaders towards female genital cutting: A cross-sectional study from the Kurdistan Region of Iraq

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    Background Understanding the perspectives of the key players in the community regarding female genital cutting (FGC) is very important for directing preventive programs. Religious leaders help shape community behaviors, which is highly pertinent in the case of FGC as it is frequently perceived to be a religious requirement. This study assesses religious leaders’ knowledge, attitudes, and positions towards FGC in the Kurdistan Region of Iraq. Methods This cross-sectional study was conducted in the Kurdistan Region of Iraq. It included a purposive sample of 147 local religious leaders (khateebs) representing the three governorates of Erbil, Sulaimaniyah, and Duhok. A self-administered questionnaire was used to collect data about the religious leaders’ knowledge, attitude, and position towards FGC. Results The participants identified reduction of the sexual desire of women as the main benefit (37%) and risk (24%) of FGC. Cultural tradition and religious requirements were the main reported reasons for practicing FGC. About 59% of the religious leaders stated that people ask for their advice on FGC. Around 14% of the participants supported performing FGC, compared to 39.1% who opposed it. Religious (73.9%) and cultural (26.1%) rationales were the main reasons given for supporting FGC. Being a cultural practice with harmful effects (53.5%) and lack of clear religious evidence (46.6%) were the main reasons for being against FGC. Around 52% of the participants recommended banning FGC by law, while 43.5% did not support banning it. A statistically significant association (P = 0.015) was found between religious leaders’ residence and their position on performing FGC. More than 46% of those residing in Duhok were against performing FGC, compared to lower proportions in Erbil (38.8%) and Sulaimaniyah (30%). Conclusion Religious leaders believed that cultural tradition was the main reason behind practicing FGC and they believed that FGC is not common in KRI, and even that it is decreasing. The religious leaders in our study reported that they could have an influential role in the FGC issue due to their position in the community. There was no statistically significant association between religious leaders’ age, education level, or work experience and their position on performing FGC. However, a statistically significant association was found between religious leaders’ residence and their position on performing FGC. A conclusive decision concerning the prohibition of FGC needs to be made by religious authorities. Health awareness activities incorporating FGC risks should be carried out to inform religious leaders at different levels of religious positions. Further research exploring perspectives of religious authorities concerning religious leaders’ inconclusive judgment about FGC is deemed necessary

    The Effect of Chloroquine, Hydroxychloroquine and Azithromycin on the Corrected QT Interval in Patients with SARS-CoV-2 Infection

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    Background - The novel SARs-CoV-2 coronavirus is responsible for the global COVID-19 pandemic. Small studies have shown a potential benefit of chloroquine/hydroxychloroquine ± azithromycin for the treatment of COVID-19. Use of these medications alone, or in combination, can lead to a prolongation of the QT interval, possibly increasing the risk of Torsade de pointes (TdP) and sudden cardiac death. Methods - Hospitalized patients treated with chloroquine/hydroxychloroquine ± azithromycin from March 1st through the 23rd at three hospitals within the Northwell Health system were included in this prospective, observational study. Serial assessments of the QT interval were performed. The primary outcome was QT prolongation resulting in TdP. Secondary outcomes included QT prolongation, the need to prematurely discontinue any of the medications due to QT prolongation and arrhythmogenic death. Results - Two hundred one patients were treated for COVID-19 with chloroquine/hydroxychloroquine. Ten patients (5.0%) received chloroquine, 191 (95.0%) received hydroxychloroquine and 119 (59.2%) also received azithromycin. The primary outcome of TdP was not observed in the entire population. Baseline QTc intervals did not differ between patients treated with chloroquine/hydroxychloroquine (monotherapy group) vs. those treated with combination group (chloroquine/hydroxychloroquine and azithromycin) (440.6 ± 24.9 ms vs. 439.9 ± 24.7 ms, p =0.834). The maximum QTc during treatment was significantly longer in the combination group vs the monotherapy group (470.4 ± 45.0 ms vs. 453.3 ± 37.0 ms, p = 0.004). Seven patients (3.5%) required discontinuation of these medications due to QTc prolongation. No arrhythmogenic deaths were reported. Conclusions - In the largest reported cohort of COVID-19 patients to date treated with chloroquine/hydroxychloroquine {plus minus} azithromycin, no instances of TdP or arrhythmogenic death were reported. Although use of these medications resulted in QT prolongation, clinicians seldomly needed to discontinue therapy. Further study of the need for QT interval monitoring is needed before final recommendations can be made

    Sengers syndrome: six novel AGK mutations in seven new families and review of the phenotypic and mutational spectrum of 29 patients

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    Background: Sengers syndrome is an autosomal recessive condition characterized by congenital cataract, hypertrophic cardiomyopathy, skeletal myopathy and lactic acidosis. Mutations in the acylglycerol kinase (AGK) gene have been recently described as the cause of Sengers syndrome in nine families. Methods: We investigated the clinical and molecular features of Sengers syndrome in seven new families; five families with the severe and two with the milder form. Results: Sequence analysis of AGK revealed compound heterozygous or homozygous predicted loss-of-function mutations in all affected individuals. A total of eight different disease alleles were identified, of which six were novel, homozygous c.523_524delAT (p.Ile175Tyrfs*2), c.424-1G > A (splice site), c.409C > T (p.Arg137*) and c.877 + 3G > T (splice site), and compound heterozygous c.871C > T (p.Gln291*) and c.1035dup (p.Ile346Tyrfs*39). All patients displayed perinatal or early-onset cardiomyopathy and cataract, clinical features pathognomonic for Sengers syndrome. Other common findings included blood lactic acidosis and tachydyspnoea while nystagmus, eosinophilia and cervical meningocele were documented in only either one or two cases. Deficiency of the adenine nucleotide translocator was found in heart and skeletal muscle biopsies from two patients associated with respiratory chain complex I deficiency. In contrast to previous findings, mitochondrial DNA content was normal in both tissues. Conclusion: We compare our findings to those in 21 previously reported AGK mutation-positive Sengers patients, confirming that Sengers syndrome is a clinically recognisable disorder of mitochondrial energy metabolism

    Development of a new drug candidate for the inhibition of Lassa virus glycoprotein and nucleoprotein by modification of evodiamine as promising therapeutic agents

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    The Lassa virus (LASV), an RNA virus prevalent in West and Central Africa, causes severe hemorrhagic fever with a high fatality rate. However, no FDA-approved treatments or vaccines exist. Two crucial proteins, LASV glycoprotein and nucleoprotein, play vital roles in pathogenesis and are potential therapeutic targets. As effective treatments for many emerging infections remain elusive, cutting-edge drug development approaches are essential, such as identifying molecular targets, screening lead molecules, and repurposing existing drugs. Bioinformatics and computational biology expedite drug discovery pipelines, using data science to identify targets, predict structures, and model interactions. These techniques also facilitate screening leads with optimal drug-like properties, reducing time, cost, and complexities associated with traditional drug development. Researchers have employed advanced computational drug design methods such as molecular docking, pharmacokinetics, drug-likeness, and molecular dynamics simulation to investigate evodiamine derivatives as potential LASV inhibitors. The results revealed remarkable binding affinities, with many outperforming standard compounds. Additionally, molecular active simulation data suggest stability when bound to target receptors. These promising findings indicate that evodiamine derivatives may offer superior pharmacokinetics and drug-likeness properties, serving as a valuable resource for professionals developing synthetic drugs to combat the Lassa virus
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