420 research outputs found
Comparative study on the performance of Au/F-TiO2 photocatalyst synthesized from Zamzam water and distilled water under blue light irradiation
Recurring problems of titanium dioxide (TiO2) for needing UV light to be activated and high electron-hole recombination rate limit the application of TiO2 as a prolific photocatalyst. By modifying the morphology and introducing electron trapping species into TiO2, the photocatalytic activity of TiO2 could be improved. Solvents of two different kinds; distilled water and Zamzam water were used in peroxotitanic acid synthesis of TiO2 and the photocatalyst was utilized to degrade Reactive Blue 19 (RB19) dye under blue light irradiation (475 nm) to assess the visible light activity of synthesized TiO2. Fluorine was incorporated to control the morphology while gold nanoparticles (GNP) stabilized by arabic gum were deposited to trap electrons. The morphology of F-TiO2 which appeared to be in ovoid shape was confirmed by Field Emission-Scanning Electron Microscope (FE-SEM) and Transmission Electron Microscope (TEM). Brunauer-Emmett-Teller (BET) surface area and crystallite size estimated from X-ray Diffraction (XRD) data revealed that F-TiO2 modified using HF was smaller in size and exhibited single anatase phase. The band gap of Au-TiO2 synthesized by distilled and Zamzam water was 2.78 eV and 2.89 eV respectively; shifted from 3.08 eV in blank TiO2. Peroxo Au/F-TiO2 synthesized with the incorporation of arabic gum as GNP stabilizer and HF as fluorine modifier degraded up to 49.23% of RB19 within two hours of reaction. The addition of fluorine and gold demonstrated high ability to enhance visible light activity of TiO2 with distilled water used as solvent displayed higher photocatalytic performance compared to Zamzam water
Terrain Mapping From Unmanned Aerial Vehicles
In land surveying, digital terrain model (DTM) and digital
surface model (DSM) have long been benefitted in many applications related to terrain mapping. Conventional methods of generating DTM and DSM have limitations in terms of practicality, time consumption and costing. The problems are much more serious for tropical regions where clouds are
persistence and tend to affect the accuracy of most of these devices. This study aims to propose a novel way of generating DTM and DSM by utilizing unmanned aerial vehicle (UAV) for different land covers including forest, plantation and developed areas in the tropical region of Malaysia. The aerial images obtained from non-matrix digital compact camera payload on UAV were processed photogrammetrically to produce terrain mapping products
including DTM, DSM and orthophoto. A detailed survey is also conducted at these areas to produce contour map as benchmark data in which is less being practiced by UAV mappers. To determine the accuracy, quantitative and qualitative analysis were carried out by means of root mean square error (RMSE) and visual inspection. The results show that the RMSE of DTM for forest, plantation and developed area are ± 1.806m, ± 0.938m and ± 0.549m, respectively while for DSM are ± 3.143m, ± 0.637m and ± 0.276m respectively. This study has determined that, the development area gives the highest accuracy compared to the plantation and forested area in which for developed and plantation area the DSM is better than DTM while vice-versa for forested area. It can be concluded that the complexity if terrain is found to be one of the key factors that influences the accuracy of the generated DSM and DTM
Epidemiology of Stroke in the MENA Region: A Systematic Review.
Introduction: Stroke is a major burden on the health system due to high fatality and major disability in survivors. Whilst Stroke incidence has declined in the developed world, it continues to increase in developing nations, including the MENA (Middle East and North Africa) region. This may reflect different risk factors and strategies to treat and manage patients prior to and after Stroke.
Methods: We have conducted a systematic review of the prevalence, incidence and mortality of Stroke in the 23 countries of MENA region following the PRISMA guidelines.
Results: 8,874 published papers were retrieved through both PubMed and Embase. Of those, 38 studies were found to be eligible for inclusion in this review. Only thirteen countries in the MENA region had data points for the critical stroke parameters. Of these qualified studies, 14 were prospective, population-based studies. In the age-adjusted studies, incidence ranged widely between 16/100,000 in a prospective population-based in Iran to 162/100,000 in Libya. Age-adjusted prevalence was available only from Tunisia at 184/100,000. Mortality for all strokes from the eight countries reporting this measure found the 30 day-case fatality ranged from 9.3% in Qatar to 30% in Pakistan. Most stroke studies in the MENA region were small sized, hospital-based, lacked confidence intervals and did not provide prevalence and mortality figures.
Conclusion: National policymakers, public health and medical care stakeholders need more reliable epidemiologic studies on Stroke from the MENA region to plan more effective preventive and therapeutic strategies
Temperature and Humidity Dependence of Air Fluorescence Yield measured by AIRFLY
The fluorescence detection of ultra high energy cosmic rays requires a
detailed knowledge of the fluorescence light emission from nitrogen molecules
over a wide range of atmospheric parameters, corresponding to altitudes typical
of the cosmic ray shower development in the atmosphere. We have studied the
temperature and humidity dependence of the fluorescence light spectrum excited
by MeV electrons in air. Results for the 313.6 nm, 337.1 nm, 353.7 nm and 391.4
nm bands are reported in this paper. We found that the temperature and humidity
dependence of the quenching process changes the fluorescence yield by a
sizeable amount (up to 20%) and its effect must be included for a precise
estimation of the energy of ultra high energy cosmic rays.Comment: presented at the 5th Fluorescence Workshop, El Escorial - Madrid,
Spain, 16 - 20 September 2007, to appear in Nuclear Instruments and Methods
Impact of soy milk consumption on cardiometabolic risk factors: A systematic review and meta-analysis of randomized controlled trials
Background: Soy milk contains some beneficial components such as isoflavones which can exert favorable effects on the cardiovascular health. The current study aimed to comprehensively evaluate the potential effects of soy milk consumption on cardiometabolic risk factors in adults. Methods: Relevant articles published up to June 2020 were systematically retrieved from SCOPUS, PubMed/MEDLINE, EMBASE, and Web of Science databases. In our study, we included all the randomized controlled trials (RCTs) investigating the impact of soy milk consumption on various cardiometabolic risk factors in adults (age � 18 years). A meta-analysis of the eligible studies was performed using the random-effects model. Results: The quantitative meta-analysis of 18 eligible RCTs (665 participants, age range 18�65 years) demonstrated that the consumption of soy milk significantly reduced systolic (P < 0.001) and diastolic (P = 0.002) blood pressure, total (P = 0.001) and low-density lipoprotein (P = 0.041) cholesterol, waist circumference (P = 0.005), C-reactive protein (P < 0.001), and tumor necrosis factor-alpha (P = 0.016). Significant between-study heterogeneity was found for the pooled effect sizes of blood pressure and low-density lipoprotein cholesterol. In addition, the subgroup analyses indicated that the decrease in systolic blood pressure (SBP) was more pronounced when soy milk was consumed for � 4 weeks. However, there were no significant differences between soy milk and control groups for the other factors, namely body weight, body mass index (BMI), high-density lipoprotein cholesterol, triglycerides, fasting blood glucose (FBG), and fasting insulin, interleukin-6, and fibrinogen. Conclusions: The current systematic review and meta-analysis revealed that incorporating soy milk into the diet might favorably affect several cardiometabolic risk factors in both healthy and unhealthy individuals. © 2021 The Author
The Fluorescence Detector of the Pierre Auger Observatory
The Pierre Auger Observatory is a hybrid detector for ultra-high energy
cosmic rays. It combines a surface array to measure secondary particles at
ground level together with a fluorescence detector to measure the development
of air showers in the atmosphere above the array. The fluorescence detector
comprises 24 large telescopes specialized for measuring the nitrogen
fluorescence caused by charged particles of cosmic ray air showers. In this
paper we describe the components of the fluorescence detector including its
optical system, the design of the camera, the electronics, and the systems for
relative and absolute calibration. We also discuss the operation and the
monitoring of the detector. Finally, we evaluate the detector performance and
precision of shower reconstructions.Comment: 53 pages. Submitted to Nuclear Instruments and Methods in Physics
Research Section
K-hindered decay of a six-quasiparticle isomer in Hf176
The structure and decay properties of high-K isomers in Hf176 have been studied using beam sweeping techniques and the Gammasphere multidetector array. A new ΔK=8 decay branch, from a Kπ=22⊃-, six-quasiparticle, isomeric (t1/2=43μs) state at 4864 keV to the 20⊃- state of a Kπ=14⊃- band, has been identified. The reduced hindrance factor per degree of K forbiddenness for this decay is measured to be unusually low (fν=3.2), which suggests K mixing in the states involved. The deduced interaction matrix elements are discussed within the context of relevant K-mixing scenarios. The 3266-keV state, previously interpreted as a Kπ=16⊃+ intrinsic state, is reassigned as the Jπ=16⊃+ member of the band based on the Kπ=15⊃+ state at 3080 keV. The systematics of fν values as a function of the degree of forbiddenness is discussed in light of this change
Interplay between octupole and quasiparticle excitations in 178Hg and 180Hg
Excited structures in the Z = 80, 178Hg (N = 98), and 180Hg (N = 100) isotopes have been investigated with the Gammasphere spectrometer in conjunction with the recoil-decay tagging technique. The present data extend the previously known ground-state bands to higher spin and excitation energy. Negative parity bands with a complex decay towards the low spin states arising from both the prolate-deformed and the nearly spherical coexisting minima have been observed for the first time in both nuclei. It is shown that these sequences have characteristics in common with negative-parity bands in the heavier even-even Hg isotopes as well as in the Os and Pt isotones. These structures are interpreted as being associated at low spin with an octupole vibration which is crossed at moderate frequency by a shape driving, two-quasiproton excitation
Safety and efficacy of transarterial embolization of hepatocellular adenomas
Background: Hepatocellular adenoma (HCA) larger than 5 cm in diameter has an increased risk of haemorrhage and malignant transformation, and is considered an indication for resection. As an alternative to resection, transarterial embolization (TAE) may play a role in prevention of complications of HCA, but its safety and efficacy are largely unknown. The aim of this study was to assess outcomes and postembolization effects of selective TAE in the management of HCA. Methods: This retrospective, multicentre cohort study included patients aged at least 18 years, diagnosed with HCA and treated with TAE. Patient characteristics, 30-day complications, tumour size before and after TAE, symptoms before and after TAE, and need for secondary interventions were analysed. Results: Overall, 59 patients with a median age of 33.5 years were included from six centres; 57 of the 59 patients were women. Median tumour size at time of TAE was 76 mm. Six of 59 patients (10 per cent) had a major complication (cyst formation or sepsis)
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