Improvisation of Power Quality in Power System with the Integration of Renewable Energy using FACTS Devices

The main goal in the power system is to transmit the power in a more economical way with high power quality and power factor, having a smaller possibility of system collapse or failure. Operation of power system network is going complex day by day and insecure with higher power flows without adequate control. Renewable energy when connected to the power grid can invite a lot of new problems and challenges. The output power of the wind generator is greatly affected by the variable nature of the wind speed which can cause power quality issues while integrating it to the grid network. The power quality issues include voltage fluctuation and reduced power factor. One solution is to introduce Flexible AC Transmission System (FACTS) like, Unified Power Flow Controller (UPFC), Static Synchronous Compensator (STATCOM) and Static Synchronous convertors. The main objective of power electronic convertors is to integrate renewable energy or any distributed generation to the standard of grid power factor. However, the troubles like injecting additional harmonics to the system due to the high switching frequency can cause immense power quality issues [1]. Custom power devices (CPD), which includes Shunt controllers like Static Synchronous Compensator or Static Var Compensator (STATCOM or SVC), Series Controllers like Static Synchronous Series Compensator (SSSC or TCSC), Combination of Series and Shunt Controller like Unified Power Flow Controller (UPFC) are used to interface devices between distributed generation and Series Compensator (SSSC) to improve the power factor and regulate the terminal voltage by installing it at the critical locations. MATLAB/PSAT is used to simulate the FACTS devices control scheme connected with the Wind turbine. And the effectiveness of the FACTS devices is tested by connecting the controllers at critical location of the power grid using IEEE 14 bus System. Keywords: Unified Power Flow Controller (UPFC), Static Compensator (STATCOM), Static Synchronous Serie

Beta-lactamase: An ideal reporter system for monitoring gene expression in live eukaryotic cells

To gain insightful information about the mechanisms through which genes are activated and repressed requires gene reporter systems that are sensitive, robust, and cost-effective. Although numerous reporter gene technologies are commercially available, none are as sophisticated and user-friendly as beta-lactamase (BLA) when it comes to studying gene expression in live cells. This article presents an overview of the BLA technology and describes how it can be exploited for studying rare events such as homologous recombination in somatic cells and be used to deliver any DNA sequence of choice anywhere within the genome

Down-regulation of DNMT3b in PC3 cells effects locus-specific DNA methylation, and represses cellular growth and migration

<p>Abstract</p> <p>Background</p> <p>Aberrations in DNA methylation patterns promote changes in gene expression patterns and are invariably associated with neoplasia. DNA methylation is carried out and maintained by several DNA methyltransferases (DNMTs) among which DNMT1 functions as a maintenance methylase while DNMT3a and 3b serve as de novo enzymes. Although DNMT3b has been shown to preferentially target the methylation of DNA sequences residing in pericentric heterochromatin whether it is involved in gene specific methylation remains an open question. To address this issue, we have silenced the expression of DNMT3b in the prostate-derived PC3 cells through RNA interference and subsequently studied the accompanied cellular changes as well as the expression profiles of selected genes.</p> <p>Results</p> <p>Our results demonstrate that DNMT3b depletion results in increased apoptosis and reduced migration of PC3 cells compared to the untransfected control cells. Reduced DNMT3b expression resulted in hypomethylation of retinoblastoma (Rb), retinoic-acid receptor β (RAR-β), and adenomatous polyposis coli (APC) gene promoters, and also culminated in increased expression of <it>CDKN3 </it>and <it>cytochrome b5</it>. Although DNMT3b silenced cells were found to have reduced growth and migratory potential, there was no apparent changes in their invasive ability compared to the parental PC3 cell line.</p> <p>Conclusion</p> <p>Our findings reveal that DNMT3b preferentially targets certain gene promoters in PC3 cells and that its depletion significantly reduces growth and migration of PC3 cells.</p

Promoter hypermethylation of tumor suppressor genes correlates with tumor grade and invasiveness in patients with urothelial bladder cancer

Purpose: To investigate the promoter methylation status at selected loci which encode for key proteins involved in apoptosis, DNA repair, cell cycle control and progression in urothelial cell carcinoma of bladder and compare the findings from tissue samples with that of plasma. Methods: Total genomic DNA was isolated from 43 non-muscle invasive (low grade) and 33 muscle invasive (high grade) urothelial bladder cancer samples along with 10 control cases of normal bladder mucosa. Promoter methylation status was investigated for RASSF1A, APC, MGMT, CDKN2A and CDKN2B genes using real-time methylation-specific PCR with SYBR® green. Plasma samples from 16 patients with muscle invasive high grade bladder cancer were also subjected to similar analyses. Results: Promoter hypermethylation was frequently observed in RASSF1A, APC and MGMT gene promoters (p-value \u3c 0.001). The methylation was more prominent in the muscle invasive high grade bladder cancer when compared to non-muscle invasive low grade group (p-value \u3c 0.001) and normal bladder mucosa (p-value \u3c 0.05). The RNA expression of RASSF1A, APC and MGMT was also found to be decreased in the muscle-invasive high grade bladder cancer when compared to the non muscle invasive low grade group (p-value \u3c 0.05). RASSF1A, MGMT and CDKN2A showed comparable results when data from 16 plasma samples was compared to the corresponding tissue samples. Conclusion: Our results suggest that epigenetic silencing of RASSF1A, APC and MGMT genes is strongly associated with invasive high grade urothelial bladder cancer. Thus, status of promoter methylation has the potential to serve as valuable tool for assessing aggressiveness of urothelial cell carcinoma of bladder

Effectiveness of plain X-ray in detection of fish and chicken bone foreign body in upper aerodigestive tract

Abstract OBJECTIVE: To assess the use of plain film radiology in the detection of fish and chicken bones in the upper aerodigestive tract. METHODS: This retrospective chart review was conducted at the Aga Khan University Hospital, Karachi, and comprised medical charts of patients who had undergone oesophagoscopy for removal of fish and chicken bone from 1990 to 2015.SPSS 19 was used for data analysis. RESULTS: Of the 24 patients, foreign body was detected on X-ray in 7(29.2%) and through fibre optic laryngoscopy in 13(54.2%).All the patients underwent surgical intervention for removal of the foreign body. Also, 19(79.2%) patients underwent direct laryngoscopy and 5(16.7%) required oesophagoscopy. The sensitivity with X-ray was 15% and specificity was zero. The sensitivity of fibre optic laryngoscopy in comparison to intra-operative findings was 65% and the specificity was 100%. CONCLUSIONS: X-ray was not found to be an ideal modality to diagnose fish or chicken bone impaction in the upper aerodigestive tract

Perceptions on bioethics among general practitioners in Karachi, Pakistan

Objective: To study the perceptions on bioethics among general practitioners in Karachi, Pakistan. Design: A questionnaire based cross sectional survey. Settings: 85 general practitioners in Karachi were surveyed at their clinic premises. Main outcome measures: Perceptions on the broad principles of bioethics. Results: The majority of general practitioners were males, with mean age of 36.3 years, had minimal postgraduate qualifications and continuing medical education. They reported the top five moral duties of a physician and their reaction in the event of the death of a close relative due to a doctor\u27s negligence. A significant number of respondents agreed that a doctor is next to God . Other issues studied include discontinuation of artificial life support, giving of gifts by pharmaceutical companies to doctors, sickness certification, organ donation, human cloning, disclosure of information to cancer patient and patient confidentiality. Conclusion: We have documented the perceptions of general practitioners on broad principles of bioethics. These views have significant implications for medical practice

Perceptions on bioethics among patients presenting to family physicians at a teaching hospital in Karachi

Objective: To study the perceptions on bioethics among patients presenting to family physicians at a teaching hospital in Karachi, Pakistan Study design: Questionnaire based cross sectional survey Settings: The study was carried out at the family practice center, the Aga Khan University Hospital, Karachi Main outcome measures: Perceptions on the broad principles of bioethics Results: Majority of the respondents were young and well educated and better placed socioeconomically. Respondents reported the moral duties of a physician and their reaction in the event of the death of a close relative due to a doctor`s negligence. The majority agreed that a doctor is next to god . Other issues studied include discontinuation of artificial life support, giving of gifts by pharmaceutical companies to doctors, sickness certification, organ donation, human cloning, disclosure of information to cancer patient and patient confidentiality. Conclusion: We have found interesting patient`s perceptions on Bioethics with important implications for clinical practic