Adaptation of VSC-HVDC Connected DFIG Based Offshore Wind Farm to Grid Codes: A Comparative Analysis

Lack of synchronism between VSC-HVDC (Voltage Source Converter - High Voltage Direct Current) connected offshore wind farm and onshore grid leads to immunity of wind turbines to grid contingencies. Focusing on DFIG (Doubly Fed Induction Generator) based wind farms; this paper has presented a univalent control structure based on inertial and primary frequency response in which DC link voltage is utilized as synchronization interface. Based on the presented structure, four approaches based on the communication system, frequency, voltage and combined frequency and voltage modulation are utilized and compared to inform the onshore grid status to individual wind turbines. Considering Kondurs two area power system, results have revealed that all four approaches have similar ability (with negligible error) in offering inertial and primary frequency response to improve slow network oscillations. On the other hand, voltage and combined frequency and voltage modulation approaches have the ability to satisfy Fault Ride Through (FRT) requirements thanks to superior dynamics. However, communication and frequency modulation approaches lose that ability as communication and frequency measurement delays increase respectively. It has been concluded that combined frequency and voltage modulation, as the superior approach, has advantages like minimum FRT DC voltage profile increase and deviation from operating point after the fault, the minimum imposition of electrical and mechanical stress on DFIG and preservation of prevalent control structure thanks to appropriate dissociation between slow and fast dynamics. ©2019. CBIORE-IJRED. All rights reserved Article History: Received Dec 8th 2017; Received in revised form July 16th 2018; Accepted December 15th 2018; Available online How to Cite This Article: Yazdi, S.S.H., Milimonfared, J. and Fathi, S.H. (2019). Adaptation of VSC-HVDC Connected DFIG Based Offshore Wind Farm to Grid Codes: A Comparative Analysis. Int. Journal of Renewable Energy Development, 8(1), 91-101. https://doi.org/10.14710/ijred.8.1.91-10

Mummy Prevents IL-1β-Induced Inflammatory Responses and Cartilage Matrix Degradation via Inhibition of NF-қB Subunits Gene Expression in Pellet Culture System

Purpose: In Persian traditional medicine, application of Mummy material has been advised since hundred years ago for treatment of different diseases as bone fracture, cutaneous wounds and joint inflammation. Regarding to the claim of indigenous people for application of this material in the treatment of joint inflammation, the present study was designed to evaluate whether Mummy can revoke the inflammatory responses in chondrocytes stimulated with interleukin 1-β (IL-1β). Methods: Isolated chondrocytes at the second passage were plated in 50 ml conical tubes at density of 1x106 for pellet culture or were plated in T75 culture flasks as monolayer. Cells in both groups were treated as control (receiving serum free culture medium), negative control (receiving IL-1β (10ng/ml for 24 hr)) and IL-1β pre-stimulated cells which treated with Mummy at concentrations of 500 and 1000µg/ml for 72hrs. After 72 hrs, to evaluate whether Mummy can revoke the inflammatory response in chondrocytes, cell in different groups were prepared for investigation of gene expression profile of collagen II, Cox-2, MMP-13, C-Rel and P65 using real-time RT-PCR. Results: Treatment of chondrocytes with IL-1β (10ng/ml) resulted in a significant increase in expression level of Cox-2, MMP-13, C-Rel and P65 in pellet culture system, while treatment of IL-1β-stimulated choncrocytes with Mummy at both concentrations of 500 and 1000µg/ml inhibited the expression level of above mentioned genes. Compared to the pellet culture, Mummy did not affect expression level of genes in monolayer condition. Conclusion: The obtained data from this investigation revealed that Mummy can be used as a potent factor for inhibiting the inflammatory responses induced by IL-1β in chondrocytes probably through inhibition of NF-қB subunits activation

Immuno-biosensor for Detection of CD20-Positive Cells Using Surface Plasmon Resonance

Purpose: Surface plasmon resonance (SPR) sensing confers a real-time assessment of molecular interactions between biomolecules and their ligands. This approach is highly sensitive and reproducible and could be employed to confirm the successful binding of drugs to cell surface targets. The specific affinity of monoclonal antibodies (MAb) for their target antigens is being utilized for development of immuno-sensors and therapeutic agents. CD20 is a surface protein of B lymphocytes which has been widely employed for immuno-targeting of B-cell related disorders. In the present study, binding ability of an anti-CD20 MAb to surface antigens of intact target cells was investigated by SPR technique. Methods: Two distinct strategies were used for immobilization of the anti-CD20 MAb onto gold (Au) chips. MUA (11-mercaptoundecanoic acid) and Staphylococcus aureus protein A (SpA) were the two systems used for this purpose. A suspension of CD20-positive Raji cells was injected in the analyte phase and the resulting interactions were analyzed and compared to those of MOLT-4 cell line as CD20-negative control. Results: Efficient binding of anti-CD20 MAb to the surface antigens of Raji cell line was confirmed by both immobilizing methods, whereas this MAb had not a noticeable affinity to the MOLT-4 cells. Conclusion: According to the outcomes, the investigated MAb had acceptable affinity and specificity to the target antigens on the cell surface and could be utilized for immuno-detection of CD20-positive intact cells by SPR method

Biological Effects of Magnetic Resonance Imaging on Testis Histology and Seminiferous Tubules Morphometry.

OBJECTIVES: Spermatogenesis is a regular and lengthy process in which the function of testicular cells may potentially be influenced by several extrinsic and intrinsic stressors, including environmental factors such as magnetic resonance imaging (MRI) waves and radiation. Our study aimed to investigate the effects of MRI waves and fields on the testicular histology and morphometry of seminiferous tubules in mice. METHODS: The experiment was conducted on 40 adult Naval Medical Research Institute mice. The control group was located in the center of the MRI bore while it was turned off, while the exposed group was exposed to the active scanner for 36 minutes once a week for three weeks. Our study included four groups: group I (control group at one hour after last exposure), group II (experimental group at one hour after last exposure), group III (control group at 35 days after last virtual exposure), and group IV (experimental group at 35 days after last exposure). We then assessed the tube and lumen diameters, as well as epithelium thickness of the seminiferous tubules. RESULTS: Our data showed that MRI waves partially reduced testicular weight one hour after the last exposure (group II) compared to group I (p = 0.240). On the other hand, in group II the Johnson's score (score 10, complete spermatogenesis and perfect tubules) was 87.5% which was slightly less than recorded in groups I, III, and IV (91.4%, 92.2%, and 90.5%, respectively). Furthermore, the MRI in group II revealed induces vacuolization in the epithelium, arrest in primary spermatocytes in the pachytene stage as well as disruption in the testicular parenchyma. CONCLUSIONS: Long-term exposure to MRI waves has deleterious effects on the male reproductive system, fertility parameters, and the quantity of germ cells in the seminiferous tubules with the exception of the number of round spermatid cells and epithelial thickness. All these effects were reversible after a new period of spermatogenesis. The OMJ is Published Bimonthly and Copyrighted 2019 by the OMSB. KEYWORDS: Fertility; Magnetic Resonance Imaging; Mice; Seminiferous Tubules; Spermatogenesis; Testi

Mummy Material Can Promote Differentiation of Adipose Derived Stem Cells into Osteoblast through Enhancement of Bone Specific Transcription Factors Expression

Purpose: Application of Mummy material for treatment of different diseases such as bone fracture, cutaneous wounds and joint inflammation has been advised since hundred years ago in Persian traditional medicine. Due to the claims of indigenous people and advice of traditional medicine for application of this material in healing of bone fractures, this study has been designed to evaluate whether Mummy material can promote the differentiation of mesenchymal stem cells into osteoblasts and enhance the expression of bone specific genes and proteins. Methods: Adipose derived stem cells (ASCs) at fourth cell passage were divided into control, osteogenesis group (received osteogenic medium), Mummy group (received Mummy at concentration of 500 µg/ml). ASCs in the fourth group were treated with both osteogenic medium and Mummy (500µg/ml). Cells in all groups were harvested on days 7, 14 and 21 days for further evaluation through Real time RT-PCR, Von kossa staining, Immunocytochemistry and flowcytometery. Results: Treatment of ASCs with Mummy at concentration of 500µg/ml promotes the expression level of Osteocalcin, RUNX-2 and β1-integrin genes in different time points but that of the Osterix did not changed. Furthermore the expression of Osteocalcin protein enhanced significantly in ASCs treated with Mummy detected by Immunocytochemistry and flowcytometery technique compared to the control groups. The results of this study also showed that treatment of ASCs with Mummy resulted in formation of mineral deposits which was evaluated by Von Kossa staining method. Conclusion: Obtained data from this study reveals that Mummy is a potent enhancer for differentiation of ASCs into osteoblasts in in vitro system, probably through increasing the level of bone specific genes and proteins

Hydrogen Peroxide Preconditioning Promotes Protective Effects of Umbilical Cord Vein Mesenchymal Stem Cells in Experimental Pulmonary Fibrosis

Purpose Idiopathic pulmonary fibrosis (IPF) is a progressive lung disorder with few available treatments. Mesenchymal stem cell therapy (MSCT), an innovative approach, has high therapeutic potential when used to treat IPF. According to recent data, preconditioning of MSCs can improve their therapeutic effects. Our research focuses on investigating the anti-inflammatory and antifibrotic effects of H2O2-preconditioned MSCs (p-MSCs) on mice with bleomycin-induced pulmonary fibrosis (PF). Methods Eight-week-old male C57BL/6 mice were induced with PF by intratracheal (IT) instillation of bleomycin (4 U/kg). Human umbilical cord vein-derived MSCs (hUCV-MSCs) were isolated and exposed to a sub-lethal concentration (15 pM for 24 h) of H2O2 in vitro. One week following the injection of bleomycin, MSCs or p-MSCs were injected (IT) into the experimental PF. The survival rate and weight of mice were recorded, and 14 days after MSCs injection, all mice were sacrificed. Lung tissue was removed from these mice to examine the myeloperoxidase (MPO) activity, histopathological changes (hematoxylin-eosin and Masson\u27s trichrome) and expression of transforming growth factor beta 1 (TGF-β1) and alpha-smooth muscle actin (α-SMA) through immunohistochemistry (IHC) staining. Results Compared to the PF+MSC group, p-MSCs transplantation results in significantly decreased connective tissue () and collagen deposition. Additionally, it is determined that lung tissue in the PF+pMSC group has increased alveolar space () and diminished expression of TGF-β1 and α-SMA. Conclusion The results demonstrate that MSCT using p-MSCs decreases inflammatory and fibrotic factors in bleomycin-induced PF, while also able to increase the therapeutic potency of MSCT in IPF

Global, regional, and national burden of disorders affecting the nervous system, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021

BackgroundDisorders affecting the nervous system are diverse and include neurodevelopmental disorders, late-life neurodegeneration, and newly emergent conditions, such as cognitive impairment following COVID-19. Previous publications from the Global Burden of Disease, Injuries, and Risk Factor Study estimated the burden of 15 neurological conditions in 2015 and 2016, but these analyses did not include neurodevelopmental disorders, as defined by the International Classification of Diseases (ICD)-11, or a subset of cases of congenital, neonatal, and infectious conditions that cause neurological damage. Here, we estimate nervous system health loss caused by 37 unique conditions and their associated risk factors globally, regionally, and nationally from 1990 to 2021.MethodsWe estimated mortality, prevalence, years lived with disability (YLDs), years of life lost (YLLs), and disability-adjusted life-years (DALYs), with corresponding 95% uncertainty intervals (UIs), by age and sex in 204 countries and territories, from 1990 to 2021. We included morbidity and deaths due to neurological conditions, for which health loss is directly due to damage to the CNS or peripheral nervous system. We also isolated neurological health loss from conditions for which nervous system morbidity is a consequence, but not the primary feature, including a subset of congenital conditions (ie, chromosomal anomalies and congenital birth defects), neonatal conditions (ie, jaundice, preterm birth, and sepsis), infectious diseases (ie, COVID-19, cystic echinococcosis, malaria, syphilis, and Zika virus disease), and diabetic neuropathy. By conducting a sequela-level analysis of the health outcomes for these conditions, only cases where nervous system damage occurred were included, and YLDs were recalculated to isolate the non-fatal burden directly attributable to nervous system health loss. A comorbidity correction was used to calculate total prevalence of all conditions that affect the nervous system combined.FindingsGlobally, the 37 conditions affecting the nervous system were collectively ranked as the leading group cause of DALYs in 2021 (443 million, 95% UI 378–521), affecting 3·40 billion (3·20–3·62) individuals (43·1%, 40·5–45·9 of the global population); global DALY counts attributed to these conditions increased by 18·2% (8·7–26·7) between 1990 and 2021. Age-standardised rates of deaths per 100 000 people attributed to these conditions decreased from 1990 to 2021 by 33·6% (27·6–38·8), and age-standardised rates of DALYs attributed to these conditions decreased by 27·0% (21·5–32·4). Age-standardised prevalence was almost stable, with a change of 1·5% (0·7–2·4). The ten conditions with the highest age-standardised DALYs in 2021 were stroke, neonatal encephalopathy, migraine, Alzheimer's disease and other dementias, diabetic neuropathy, meningitis, epilepsy, neurological complications due to preterm birth, autism spectrum disorder, and nervous system cancer.InterpretationAs the leading cause of overall disease burden in the world, with increasing global DALY counts, effective prevention, treatment, and rehabilitation strategies for disorders affecting the nervous system are needed

“Smart water” as a wettability modifier in chalk: The effect of salinity and ionic composition

"Reprinted (adapted) with permission from Fathi, S J., Austad, T., Strand S. (2010) “Smart water” as a wettability modifier in chalk: The effect of salinity and ionic composition. Energy & Fuels 24(4), pp. 2514–2519. Copyright 2010 American Chemical Society. The article forms part of Jafar Fathi's PhD thesis: Water-based enhanced oil recovery (EOR) in carbonate reservoirs : initial wetting condition and wettability alteration by "Smart Water", Stavanger : University of StavangerSeawater can improve the water wetness of chalk at high temperatures, which improves the oil displacement by spontaneous imbibition of water. It is experimentally verified that the interaction between Ca2+, Mg2+, and SO42− at the chalk surface will displace adsorbed carboxylic acids and increase the water wetness. In this work, the effect of salinity and ionic composition of smart water on oil recovery was studied at different temperatures, 100, 110, and 120 °C. The ultimate oil recovery was compared using seawater as the base fluid. When NaCl was removed from seawater, both the imbibition rate and oil recovery increased in comparison to seawater at the temperatures tested. At 110 and 120 °C, the oil recovery from seawater depleted in NaCl increased by about 10% of original oil in place (OOIP) compared to seawater. A decrease in oil recovery of about 5% of OOIP was observed when increasing the amount of NaCl in seawater 4 times. A systematic decrease in oil recovery was observed when using seawater diluted with distilled water as imbibing fluid. Imbibition tests at 110 °C showed that the water-wet fraction increased 29% for seawater depleted in NaCl compared to 11% for ordinary seawater. Diluted seawater to 10 000 ppm did not change wetting conditions at 110 °C. The results confirmed that not only is the concentration of the active ions Ca2+, Mg2+, and SO42− important for wettability alteration to take place but also the amount of non-active salt, such as NaCl, has an impact on the wettability alteration process, which is discussed as a double-layer effect at the chalk surface. No significant improvement in the ultimate oil recovery was observed during forced displacement by modified seawater