41 research outputs found
Radial distribution network reconfiguration for power losses reduction using a modified particle swarm optimisation
Abstract: Recently, losses reduction gained a great deal of attention in distribution system due to low-voltage level and the high-current passing through the lines, pushing the distribution utilities to improve their profit margins on one hand by reducing the unnecessary operational cost, and improving their delivered power quality on the other hand by maintaining the system reliability, and the continuity of supply for varying load demand. Load balancing, voltage regulation, network reconfiguration and others are different techniques used to reduce the losses. This study addresses the distribution network reconfiguration to minimise the network losses. A new modified form of particle swarm optimisation (PSO) is used to identify the optimal configuration of distribution network effectively. The difference between the modified PSO (MPSO) algorithms and the typical one is the filtered random selective search space for initial position, which is proposed to accelerate the algorithm for reaching the optimum solution. The suggested MPSO is tested via 33 and 69 IEEE networks. A benchmark comparison has been conducted to prove the effectiveness of MPSO compared with previous optimisation techniques
Utilization of Battery Energy Storage Systems (BESS) in Smart Grid: A Review
The uncertainty in fuel cost, the ageing of most existing grid, the lack of utilities’ supply capacity to respond to the increasing load demand, and the lack of automatically power restoration, accelerate the need to modernize the distribution network by introducing new technologies, putting the smart grid (SG) on spot. The aim of this paper is to carry out a detailed survey of the major requirements of (SG) and discuss the operational challenges arising from the integration of distributed generation (DG) in distribution networks (DN). These requirements dictate the necessity to review the energy and communication infrastructure, the automatic control, metering and monitoring systems, and highlight the features of smart protection system for a robust and efficient distribution grid. In addition, the paper aims to classify the energy storage systems (ESS) and explain their role for utilities, consumers and for environment. This includes the pumped hydro systems (PHS) and compressed air systems (CAS), battery energy storage systems (BESSs), double layer and superconductive capacitors, and electric vehicles (EVs). Since BESSs emerged as one of the most promising technology for several power applications, the paper presents an overview of their main features, management and control systems and operational modes. A survey about the utilization of BESSs in power system is presented
Rad5, HLTF, and SHPRH: A fresh view of an old story
Not only have helicase-like transcription factor (HLTF) and SNF2 histone-linker PHD-finger RING-finger helicase (SHPRH) proved to be important players in post-replication repair like their yeast counterpart, Rad5, but they are also involved in multiple biological functions and are associated with several human disorders. We provide here an updated view of their functions, associated diseases, and potential therapeutic approaches
Chemical screening identifies the β-Carboline alkaloid harmine to be synergistically lethal with doxorubicin.
Despite being an invaluable chemotherapeutic agent for several types of cancer, the clinical utility of doxorubicin is hampered by its age-related and dose-dependent cardiotoxicity. Co-administration of dexrazoxane as a cardioprotective agent has been proposed, however recent studies suggest that it attenuates doxorubicin-induced antitumor activity. Since compounds of natural origin present a rich territory for drug discovery, we set out to identify putative natural compounds with the view to mitigate or minimize doxorubicin cardiotoxicity. We identify the DYRK1A kinase inhibitor harmine, which phosphorylates Tau that is deregulated in Alzheimer's disease, as a potentiator of cell death induced by non-toxic doses of doxorubicin. These observations suggest that harmine or other compounds that target the DYRK1A kinase my offer a new therapeutic opportunity to suppress doxorubicin age-related and dose-dependent cardiotoxicity
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
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.
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
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