Optimal relay coordination of an adaptive protection scheme using modified PSO algorithm.

Recently, future smart grids are described by a dominantly fluctuating character due to the power consumption change from peak to off-peak loading conditions, the operation of micro-grids in grid-connected or islanded mode and other possible network topologies resulting in an effective change in network impedances and short circuit current level. Therefore, the situation from protection sensitivity, selectivity and speed may become more and more challenging. In this paper, Adaptive protection scheme is proposed to respond to structural variations occurred in interconnected power systems. A designed software based on Modified Particle Swarm Optimization (MPSO) algorithm is suggested to solve the relay coordination problem in modern distribution networks. In this study, the 14 IEEE bus system is tested via three power system scenarios showing the effect of adding and disconnecting of DG units and the occurrence of sudden line outages on the system. The obtained results show that the proposed algorithm has achieved optimum relay settings for each existing network topology

Developing an adaptive protection scheme towards promoting the deployment of distributed renewable sources in modern distribution networks: operational simulation phase.

The large-scale integration of renewables into the electricity grid as distributed generation sources for providing clean energy supply together with the recent introduction of the smart grid concept, have accelerated the need to modernize the existing protection schemes to accommodate the challenges originated from distributed generation. This paper presents an adaptive protection scheme that has been developed to allow automatic adjustment of optimal relay settings in response to multiple network topologies and unexpected variations arising from renewable energy systems integration towards promoting their deployment in modern distribution networks. A Simulink model is developed to simulate the operation of the adaptive protection scheme, being interlinked to a linear-programming technique to allow optimizing the relay settings in response to dynamic changes of network topology associated with the integration of distributed generation sources. The performance of the developed adaptive protection scheme in accommodating the dynamic changes of network topology has been assessed under two proposed network topologies using a small-scale network that has been built in the lab as part of experimental work for the purpose of implementing the adaptive control unit. Results have demonstrated the effectiveness of the developed approach in optimizing the relay settings in response to the subjected topology changes, achieving minimum relay trip times while ensuring a suitable relay coordination is satisfied in each of the tested network topologies

Towards digitalized and automated substations: implementation of adaptive protection control unit and monitoring system for modern distribution networks under increased hosting capacity of distributed renewable sources.

Maximizing the hosting capacity of modern distribution networks to accommodate more distributed renewable sources is key driver to realise energy system security and Net-Zero carbon goals. Protection systems under increased share of renewable sources became more challenging with diverse topology changes originated from the addition, disconnection, or islanding of distributed generation to secure increasing energy demands. This paper aims to implement an adaptive protection control unit interlinked with an interactive monitoring system to enable the real-world application of smart adaptive protection schemes for modern distribution networks under increased hosting capacity of distributed renewable sources. An adaptive protection control kit is experimentally developed to enable the automatic adjustment of optimal relay settings in response to network topology changes arising from the integration of distributed generation. A set of relay settings are pre-optimized within a small-scale meshed network under possible network topologies and stored offline via a master microcontroller which then uses the online breaker status to identify the corresponding network topology and accordingly adjust the pre-optimized relay settings. A human machine interface is further designed and interlinked with the experimentally developed control kit via a slave microcontroller, providing real-time data of actual current measurements and waveforms together with topological changes and self-adaptation of pre-optimized relay settings. Experimental results showed successful adjustment of pre-optimized relay settings in response to topological changes while achieving coordination time intervals within acceptable limits under the tested network topologies

Adrenal medulla of AS/AGU rats: a histological and immunohistochemical study

Background: The outcome of the autograft therapy for Parkinson’s disease including autologous cells from adrenal medulla was disappointing. This could be attributed to the pathological process in Parkinson’s disease affecting cells of the adrenal medulla. This study was performed to investigate the histopathological changes in the adrenal medulla of AS/AGU rat, a model of Parkinson’s disease, in comparison with Albino Swiss (AS) rats. Materials and methods: A total of 24 male AS rats were divided into four groups, each of 6 animals: AS W1 — AS rats aged 1 week; AS adult — AS adult rats; AS/ /AGU W1 — AS/AGU rats aged 1 week; and AS/AGU adult — AS/AGU adult rats. The rats were sacrificed and the adrenal glands were dissected and processed for histological staining with haematoxylin and eosin and periodic acid Schiff and for immunohistochemical staining for S100 protein, ubiquitin and tyrosine hydroxylase. Results: The histological investigation of the adrenal medulla of AS/AGU rats showed vascular congestion, inflammatory cellular infiltration, pyknotic nuclei, necrotic chromaffin cells and medullary inclusion bodies. The immunohistochemical investigation of AS/AGU rats showed a statistically significant decrease in the expression of S100 protein, ubiquitin and tyrosine hydroxylase compared to AS rats. Conclusions: The histological and immunohistological changes in the adrenal medulla could explain the failure of outcome of adrenal autograft therapy in Parkinson’s disease.

Collagen types I and II distribution: a relevant indicator for the functional properties of articular cartilage in immobilised and remobilised rabbit knee joints

The objective of the present work was to study changes in collagen type I and type II distribution in the articular cartilage of immobilised and remobilised rabbit knee joints. Twenty-four adult male rabbits were divided into three groups. One of the groups was a control group with free movement. The right knee joints of animals of the other two groups were immobilised for 4 weeks, followed by a period of 10 weeks of remobilisation for animals of group 3. Collagen type I and type II in the articular cartilage of tibial medial condyle of the right knee joint were estimated immunohistochemically in all groups. A degenerative process was evident after 4 weeks of immobilisation of rabbit knee joint leading to a partial shift in the density of collagen composition from type II to type I. After a period of 10 weeks of remobilisation, regenerative processes, evidenced by a restoration of collagen type II to normal, proceeded on top of degenerative processes, evidenced by the significantly higher content of collagen type I compared with normal. The present study pointed to the importance of assessment of collagen distribution as a relevant indicator for the functional properties of articular cartilage in immobilised and remobilised joints

Curcumin ameliorates experimental autoimmune acute myocarditis in rats as evidenced by decrease in thioredoxin immunoreactivity

This study was performed to investigate the effect of curcumin on cardiac myosin-induced autoimmune myocarditis in rats and the change in thioredoxin (TRX) immunoreactivity in cardiomyocytes following curcumin treatment. Twenty-four six-week-old male Wistar rats were randomly allocated into 4 groups of 6 rats each. Group I received neither curcumin nor myosin. Group II received an oral solution of 1 g/kg/day of curcumin daily, from day 1 to day 21. To induce myocarditis, animals of both group III and group IV were injected by 1 mg of porcine cardiac myosin on days 1 and 8. In addition, animals of group IV received an oral solution of 1 g/kg/day of curcumin daily, from day 1 to day 21. Serum levels of creatine phosphokinase, troponin-T, tumour necrosis factor-alpha and interleukin-6 were estimated. Hearts were processed for histopathological and immunohistochemical studies. Serum biomarkers levels were significantly increased in myocarditis group as compared to other groups. The intake of curcumin significantly reduced the deviation in these markers. Sections of the wall of the heart from myocarditis group were characterised by inflammatory cell infiltration. Most of cardiomyocytes showed pyknotic nuclei and increased sarcoplasmic eosinophilia with strong immunoreactivity for TRX. Sections from myocarditis-curcumin group showed normal architecture with moderate immunoreactivity for TRX. The present study demonstrated that curcumin ameliorates acute myocarditis in rats and encouraged the estimation of serum level of TRX as a relevant indicator for the evaluation of the progress of acute myocarditis

Role of quercetin and arginine in ameliorating nano zinc oxide-induced nephrotoxicity in rats

BACKGROUND: Nanoparticles are small-scale substances (<100 nm) with unique properties. Therefore, nanoparticles pose complex health risk implications. The objective of this study was to detect whether treatment with quercetin (Qur) and/or arginine (Arg) ameliorated nephrotoxicity induced by two different doses of nano zinc oxide (n-ZnO) particles. METHOD: ZnO nanoparticles were administered orally in two doses (either 600 mg or 1 g/Kg body weight/day for 5 conscutive days) to Wister albino rats. In order to detect the protective effects of the studied antioxidants against n-ZnO induced nepherotoxicity, different biochemical parameters were investigated. Moreover, histopathological examination of kidney tissue was performed. RESULTS: Nano zinc oxide-induced nephrotoxicity was confirmed by the elevation in serum inflammatory markers including: tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6); and C-reactive protein (CRP). Moreover, immunoglobulin (IGg), vascular endothelium growth factor (VEGF), and nitric oxide (NO) were significantly increased in rat serum. Serum urea and creatinine levels were also significantly increased in rats intoxicated with n-ZnO particles compared with the control group. Additionally, a significant decrease in the non-enzymatic antioxidant reduced glutathione (GSH) was shown in kidney tissues and serum glucose levels were increased. These biochemical findings were supported by a histopathological examination of kidney tissues, which showed that in the animals that received a high dose of n-ZnO, numerous kidney glomeruli underwent atrophy and fragmentation. Moreover, the renal tubules showed epithelial desquamation, degeneration and necrosis. Some renal tubules showed casts in their lumina. Severe congestion was also observed in renal interstitium. These effects were dose dependent. Cotreatment of rats with Qur and/or Arg along with n-ZnO significantly improved most of the deviated tested parameters. CONCLUSIONS: The data show that Qur has a beneficial effect against n-ZnO oxidative stress and related vascular complications. Also, its combination with Arg proved to be even more effective in ameliorating nano zinc oxide nephrotoxicity

Anoctamin1 and c-Kit immunohistochemical study of interstitial cells of Cajal in the muscularis externa of human gastrointestinal tract

Background: Interstitial cells of Cajal )ICC) are widely distributed in human gastrointestinal (GI) tract  specially in the layer of muscularis externa between neurons and smooth muscles. They play a very important role of coordination of GI tract motility. The aims of this research were to study the morphology and distribution of ICC in the muscularis externa of the GI tract, using immunohistochemistry staining methods, to determine the distribution of immune reactivity of Anoctamin1 (Ano1) compared with c-Kit, and to determine if Ano1 is a reliable marker for ICC in human GI tract. Materials and methods: Specimens from the wall of stomach, small intestine, and colon were taken from human cadavers and processed for histological and immunohistochemical study using c-Kit and Ano1 primary antibodies. Results: ICC appeared as bipolar cells, not forming network, in both the circular and longitudinal muscle layers, while in the myenteric area they appeared as multipolar interconnected cells. They were unevenly distributed in and between the muscle layers of the muscularis externa of human GI tract. They were more numerous in the stomach followed by the colon then the small intestine, and more numerous in the myenteric area followed by the circular muscle layer then the longitudinal muscle layer, in the three organs. Our results also showed that Ano1 is a more reliable marker for human ICC than c-kit. Conclusions: ICC differed in morphology and were unevenly distributed between muscle layers of muscularis externa and between different parts of human GI tract

Thymoquinone and curcumin modify inducible nitric oxide synthase, caspase 3, and thioredoxin immunohistochemical expression in acetaminophen hepatotoxicity

Background: Acetaminophen (APAP) hepatotoxicity is characterised by an extensive oxidative stress due to depletion of glutathione (GSH), which results in massive lipid peroxidation and subsequent liver injury. The current paradigm suggests that mitochondria are the main source of reactive oxygen species (ROS), which impair mitochondrial function and are responsible for cell signalling resulting in cell death. This study was designed to compare the potential impact of thymoquinone (THQ), and/or curcumin (CURC) on liver injury induced by APAP toxicity in rats. Materials and methods: Serum levels of alanine transaminase, aspartate transaminase, total bilirubin, and total protein were measured. In addition, liver nitric oxide (NO), malondialdehyde, reduced glutathione (GSH), and superoxide dismutase (SOD) were estimated. Moreover, these biochemical parameters were confirmed by histopathological and immunohistochemical investigations for the expression of thioredoxin, iNOS and caspase 3. Results: Acetaminophen toxicity elevated most of the above-mentioned parameters but decreased GSH, SOD, and total protein levels. Histologically, liver sections demonstrated liver injury characterised by hepatocellular necrosis with nuclear pyknosis, karyorrhexis and karyolysis. Immunohistochemical study revealed increased expression of iNOS and caspase 3 proteins, while the thioredoxin protein expression was decreased. Conclusions: Treatment with the THQ and CURC regulated the biochemical and histopathological alterations induced by APAP toxicity. It was concluded that the combination strategy of THQ and CURC might be considered as a potential antidote in combating liver injury induced by APAP with minimal side effects