3,354 research outputs found
Detection and Identification of Arcobacter species in Poultry in Assiut Governorate, Upper Egypt
This work aimed to detect, identify and study the epidemiology of Arcobacter species in avian species in Upper Egypt. A total 600 samples, including cloacal swabs and intestinal samples were collected from chickens, turkeys and ducks in Assiut Governorate in Upper Egypt. Using conventional phenotypic methods for isolation and identification, Arcobacter species could be isolated and identified with percentage 25.5% in chickens, 9.5% in turkeys and 14% in ducks. Sixteen randomly selected phenotypically identified Arcobacter species isolates were confirmed using one step multiplex PCR assay. In conclusion, Arcobacter species could be detected and identified from various avian species with variable incidence. Conventional phenotypic methods for detection and differentiation of Arcobacter species are often hampered by many limitations, while molecular methods, and PCR, in particular can provide a sensitive and rapid alternative method for detection and identification of Arcobacter species in different domestic poultry species
Is Low Alveolar Type II Cell SOD3 in the Lungs of Elderly Linked to the Observed Severity of COVID-19?
Human lungs single cell RNA sequencing data from healthy donors (elderly and young; GEO accession number GSE122960) were analyzed to isolate and specifically study gene expression in alveolar type II cells. Co-localization of ACE2 and TMPRSS2 enables SARS-CoV 2 to enter the cells. Expression of these genes in the alveolar type II cells of elderly and young patients were comparable and therefore do not seem to be responsible for worse outcomes observed in COVID-19 affected elderly. In cells from the elderly, 263 genes were downregulated and 95 upregulated. SOD3 was identified as the top-ranked gene that was most down-regulated in the elderly. Other redox-active genes that were also downregulated in cells from the elderly included ATF4 and M2TA. ATF4, an ER stress sensor that defends lungs via induction of heme oxygenase 1. The study of downstream factors known to be induced by ATF4, according to Ingenuity Pathway AnalysisTM, identified 24 candidates. Twenty-one of these were significantly downregulated in the cells from the elderly. These downregulated candidates were subjected to enrichment using the Reactome Database identifying that in the elderly, the ability to respond to heme deficiency and the ATF4-dependent ability to respond to endoplasmic reticulum stress is significantly compromised. SOD3-based therapeutic strategies have provided beneficial results in treating lung disorders including fibrosis. The findings of this work propose the hypotheses that lung-specific delivery of SOD3/ATF4 related antioxidants may work in synergy with promising anti-viral drugs such as remdesivir to further improve COVID-19 outcomes in the elderly
Design and Simulation of Modular Multilevel Converter Fed Induction Motor Drive
Traditional modular multilevel converter (MMC) applications in medium voltage induction motor drive are difficult, particularly at low speeds because of the higher magnitude of the voltage ripple of the sub-module capacitor. This paper uses a hybrid MMC, particularly at low frequencies, to achieve a lower peak-to-peak voltage ripple of the sub-module capacitor. The vector control strategy with the closed-loop speed control indicates an accurate and wide-speed range. MATLAB / Simulink is used to simulate and obtain the simulation results of hybrid and traditional MMC with induction motor drive and compare from the standpoint of capacitor voltage ripple. The results are shown the reduction of peak-to-peak voltage ripple of the sub-module capacitor as the hybrid MMC is operated
Design of GCSC Stabilizing Controller for Damping Low Frequency Oscillations
This paper presents a systematic procedure for modeling and simulation of a power system equipped with FACTS type Gate Controlled Series Compensator (GCSC) based stabilizer controller. Single Machine Infinite Bus (SMIB) power system was investigated for evaluation of GCSC stabilizing controller for enhancing the overall dynamic system performance. PSO algorithm is employed to compute the optimal parameters of damping controller. Eigenvalues of system under various operating condition and nonlinear time domain simulation is employed to verify the effectiveness and robustness of GCSC stabilizing controller in damping low frequency oscillations (LFO) modes
A Green Synthesis of Iron/Copper Nanoparticles as a Catalytic of Fenton-like Reactions for Removal of Orange G Dye
تدرس هذه الورقة البحثية استخدام طريقة صديقة للبيئة وغير مكلفة لإزالة الصبغة البرتقالية G (OG) من المحلول المائي، حيث تم استخدام مستخلص أوراق شجرة الفيكس لغرض التخليق الأخضر لجسيمات الحديد/نحاس ثنائية الفلز النانوية (G-Fe/Cu-NPs). بعد أن تم تحضير G-Fe/Cu-NPs تم تشخيصها باستخدام مجهر الماسح الالكتروني، BET، مجهر القوة الذرية، مطياف الطاقة المشتتة، مطيافية الأشعة تحت الحمراء، و مقياس زيتا. أظهرت نتائج التشخيص بأن شكل G-Fe/Cu-NPs كان مستدير شبه كروي ويتراوح الحجم بين 32-59 نانومتر بينما كانت مساحتها السطحية 4.452 م2/غم. فيما بعد اُستخدمت الجسيمات النانوية الناتجة كعامل مساعد في تفاعلات الأكسدة الشبيهة بالفنتون. حيث أن كفاءة تحلل صبغة OG اعتمدت بشكل كبير على تركيز الهيدروجين بيروكسايد (1.7-5.28 ملي مولاري)، كمية العامل المساعد (0.4-1.6 غم/لتر)، درجة الحامضية (2-7)، تركيز OG الابتدائي (25-75 ملغم/لتر) ودرجة الحرارة (20-50 درجة مئوية). أظهرت التجارب الدفعية أن 94.8% لتركيز 50 ملغم/لتر من صبغة OG تمت ازالته عند الظروف المثلى للهيديروجين بيروكسايد، كمية العامل المساعد، درجة الحامضية، ودرجة الحرارة والتي كانت 3.52 ملي مولاري،1غم/لتر، 3، و 40 درجة مئوية على التوالي خلال زمن مقداره 30 دقيقة. أيضاً أظهرت نتائج دراسة النماذج الحركية بأن ازالة صبغة OG تتبع نموذج حركي من الدرجة الثانية. أخيراً، تم دراسة الديناميكية الحرارية للتفاعل وخلُصت إلى ان التفاعل ماصاً للحرارة وله طاقة تنشيط مقدارها 29.725 كيلوجول/مول.This research paper studies the use of an environmentally and not expensive method to degrade Orange G dye (OG) from the aqueous solution, where the extract of ficus leaves has been used to fabricate the green bimetallic iron/copper nanoparticles (G-Fe/Cu-NPs). The fabricated G‑Fe/Cu-NPs were characterized utilizing scanning electron microscopy, BET, atomic force microscopy, energy dispersive spectroscopy, Fourier-transform infrared spectroscopy and zeta potential. The rounded and shaped as like spherical nanoparticles were found for G-Fe/Cu‑NPs with the size ranged 32-59 nm and the surface area was 4.452 m2/g. Then the resultant nanoparticles were utilized as a Fenton-like oxidation catalyst. The degradation efficiency of OG dye highly depends on H2O2 concentration (1.7-5.28 mM), catalyst dose (0.4-1.6 g/L), pH (2-7), initial OG concentration (25-75 mg/L), and temperature (20-50 ℃). Batch experiments showed that 94.8 % of 50 mg/L of OG dye was removed within the optimum peroxide concentration, dose, pH and temperature which were 3.52 mM, 1 g/L, 3, and 40℃ respectively along with 30 min contact time. The results of kinetic models showed that OG removal followed the second-order model. Finally, the thermodynamic study of reaction was also examined and concluded to endothermic reaction with 29.725 kJ/mol activation energy
Optimizing the Dynamic Performance of a Wind Driven Standalone DFIG Using an Advanced Control Algorithm
The article seeks to improve the dynamic performance of a standalone doubly fed induction generator (DFIG) which driven by a wind turbine, with the help of an effective control approach. The superiority of the designed predictive controller can be confirmed through evaluating the performance of the DFIG under other control algorithm, which is the model predictive direct torque control (MPDTC), model predictive current control (MPCC) as classic types of control. Firstly, the operating principles of the two controllers are described in details. After that, a comprehensive comparison is performed among the dynamic performances of the designed MPDTC, MPCC techniques and the predictive control strategy, so we can easily present the merits and deficiencies of each control scheme to be able to easily select the most appropriate algorithm to be utilized with the DFIG. The comparison is carried out in terms of system simplicity, dynamic response, ripples’ content, number of performed commutations and total harmonic distortion (THD). The results of the comparison prove the effectiveness and validation of our proposed predictive controller; as it achieves the system simplicity, its dynamic response is faster than that of MPDTC and MPCC, it presents a lower content of ripples compared to MPDTC and MPCC. Moreover, it can minimize the computational burden, remarkably. Furthermore, the numerical results are showing a marked reduction in the THD with a percentage of 2.23 % compared to MPDTC and 1.8 % compared to MPCC. For these reasons, it can be said that the formulated controller is the most convenient to be used with the DFIG to achieve the best dynamic performance
PVA/Chitosan/Silver Nanoparticles Electrospun Nanocomposites: Molecular Relaxations Investigated by Modern Broadband Dielectric Spectroscopy
In this study, we used broadband dielectric spectroscopy to analyze polymer nanofibers of poly(vinyl alcohol)/chitosan/silver nanoparticles. We also studied the effect of incorporating silver nanoparticles in the polymeric mat, on the chain motion dynamics and their interactions with chitosan nanofibers, and we calculated the activation energies of the sub-Tg relaxation processes. Results revealed the existence of two sub-Tg relaxations, the first gets activated at very low temperature (−90 °C) and accounts for motions of the side groups within the repeating unit such as –NH2, –OH, and –CH2OH in chitosan and poly(vinyl alcohol). The second process gets activated around −10 °C and it is thought to be related to the local main chain segments’ motions that are facilitated by fluctuations within the glycosidic bonds of chitosan. The activation energy for the chitosan/PVA/AgNPs nanocomposite nanofibers is much higher than that of the chitosan control film due to the presence of strong interactions between the amine groups and the silver nanoparticles. Kramers–Krönig integral transformation of the ε′′ vs. f spectra in the region of the chitosan Tg helped resolve this relaxation and displayed the progress of its maxima with increasing temperature in the regular manner
Effect of sorbitol in callus induction and plant regeneration in wheat
Six wheat genotypes were evaluated for their response to callus induction and regeneration on MS medium modified with different concentrations of sorbitol, that is, 0, 10, 20, 30 gL-1 along with optimum (3 mgL-1) concentration of 2,4-D. Variability was observed among different genotypes for callus induction. Highest callus induction frequency was shown by Wafaq- 2001, which was about 85.62% followed by Inqalab-91 which showed 71.94% callus induction. While minimum callus induction frequency was shown by Saleem-2000 which was about 51.21%. Regarding sorbitol concentration highest average callus induction frequency (79.20%) was obtained at 20 gL-1 and lowest average callus induction frequency (59.20%) was observed at 30 gL-1. In Wafaq-2001 and Inqalab-91 plant regeneration increased gradually by increasing the sorbitol concentration from 0 to 20 gL-1 but then it decreased. Similarly Auqab-2002 had no regeneration al all on non-sorbitol medium but showed regeneration on addition of sorbitol. Similarly time duration required for plant regeneration also decreased by increasing the concentration of sorbitol. It was also observed that sorbitol has given more strength to regenerated plant
Case studies of six CBFM-2 water bodies
The case studies report on how CBFM-2 interventions have affected aquatic productivity, income, employment and livelihoods in six case study sites, Beelbhora beel cluster (Kishoreganj), Sholuar beel (Narail), Chapundaha beel (Rangpur), Hamil beel (Tangail), Kutir beel (Kishoreganj) and Dikshi beel (Pabna).
- …