Steady State Voltage Stability Enhancement Using Shunt and Series FACTS Devices

It is specifically important to focus on voltage stability analysis of the power system to avoid worst case scenarios such as voltage collapse. The purpose of this thesis is to identify methods for enhancing the steady-state voltage stability using FACTS devices and determining their impact on real and reactive power losses, improvement of bus voltage magnitude, and transmission line loadability. To achieve this, FACTS devices such as Static VAR Compensator (SVC), Static Synchronous Compensator (STATCOM), and Thyristor Controlled Series Capacitor (TCSC) are used in the test system as three separate test cases. The results obtained assist in drawing conclusions on the effectiveness of each FACTS devices at generator, load and swing buses, on lines between two load buses, and between a load bus and a generator bus, in terms of metrics such as voltage magnitude profile, PV curves, and active and reactive power losses

AV Nodal Reentrant Tachycardia Causing Inappropriate ICD Shocks In A Patient With Arrhythmogenic RV Dysplasia

We report a patient with an implantable cardioverter defibrillator (ICD) for arrhythmogenic right ventricular dysplasia (ARVD) who received inappropriate shocks for atrioventricular node reentry tachycardia (AVRNT). Patient had multiple shocks for tachycardia with EGM characteristics of very short VA interval and CL of 300 msec. An electrophysiologic (EP) study reproducibly induced typical AVNRT with similar features. The slow AV nodal pathway ablation resolved the ICD shocks. Despite increasingly sophisticated discrimination algorithms available in modern ICDs, the ability to differentiate SVT from VT can be challenging. Our patient received inappropriate shocks for AVNRT. When device interrogation alone is not conclusive, an EP study may be necessary to determine the appropriate therapeutic course

Povećana isporuka etopozida u Daltonov limfom u miševa pomoću micela s polisorbatom 20

The study evaluates the possibility of enhancing uptake of etoposide (topoisomerase II inhibitor) by tumor when delivered through Polysorbate 20 micelles. The micelle formation was ascertained by determining the critical micellar concentration (CMC) with a du Nouy ring tensiometer and by size measurement using dynamic light scattering. Addition of 5% ethanol decreased the CMC of Polysorbate 20 (from 5.0 x 10-5 to 4.54 x 10-5 mol L-1). Etoposide (ET) and etoposide loaded Polysorbate 20 micelles (EPM) were radiolabeled with 99mTc by the reduction method using stannous chloride. Labeling parameters were optimized to obtain high labeling efficiency. The diethylenetriamine pentaacetic acid and cysteine challenge tests showed very low transchelation of 99mTc-ET and 99mTc-EPM complexes indicating their in vitro stability. The complexes also exhibited serum stability assessed by ascending thin layer chromatography. Subcutaneous injection of EPM resulted in significantly higher tumor uptake (~ 100 folds compared to ET 6 h post injection) (p < 0.001) and prolonged tumor retention. Tumor uptake was also confirmed by gamma imaging studies. EPM exhibited relatively high brain concentrations (~7 fold 24 h post injection) compared to ET, suggesting the potential use of EPM in the treatment of brain malignancies.U radu je proučavan ulazak etopozida (inhibitora topoizomeraze II) u tumorsko tkivo iz micela s polisorbatom 20. Oblikovanje micela je potvrđeno određivanjem kritične micelarne koncentracije (CMC) pomoću du Nouy kružnog tenziometra i mjerenjem veličine čestica metodom rasapa svjetlosti. Dodatak 5% etanola smanjuje CMC polisorbata 20 (od 5,0 x 10-5 do 4,54 x 10-5 mol L-1). Etoposid (ET) i micele etoposida s polisorbatom 20 (EPM) obilježene su radioizotopom 99mTc redukcijom pomoću kositrova klorida. Parameteri markiranja su optimirani. Testovi s dietilentriamin pentaoctenom kiselinom i cisteinom pokazali su vrlo nisko transkeliranje 99mTc-ET i 99mTc-EPM kompleksa, što ukazuje na njihovu stabilnost u uvjetima in vitro. Uzlaznom tankoslojnom kromatografijom dokazana je i stabilnost kompleksa u serumu. Nakon subkutane primjene EPM isporuka etopozida u tumorsko tkivo bila je značajno veća (~ 100 puta u odnosu na ET 6 h poslije injiciranja) (p < 0,001), a dokazano je i produljeno zadržavanje EPM u tumoru. Ulazak u tumor je potvrđen i gama analizom slike. EPM je postigao relativno visoku koncentraciju u mozgu u usporedbi s ET (~ 7 puta veću 24 h poslije injiciranja), zbog čega bi se potencijalno mogao upotrijebiti u terapiji malignih tumora mozga

Brza i osjetljiva HPLC metoda za određivanje doksorubicina u krvi psa Artifakt srebrovog nitrata

A rapid and sensitive high performance liquid chromatographic (HPLC) assay utilizing fluorimetric detection (excitation at 480 nm, emission at 560 nm) for the determination of doxorubicin in dog blood was developed and validated. Treatment of blood samples containing doxorubicin with AgNO3 (as protein precipitant) resulted in appearance of an additional peak in the chromatogram of doxorubicin at 11.5 min along with the parent peak (tR = 5.5 min). The latter peak was not found when treated with other protein precipitants such as trichloroacetic acid and methanol. Construction of calibration curve based on area of both peaks alone did not result in linearity of the curve. However, summation of areas of both peaks resulted in a curve with good linearity and correlation coefficient (R2 = 0.9985). Appearance of second peak may be due to the interaction of doxorubicin with cellular components of blood in the presence of AgNO3 leading to the formation of complex with reduced polarity. Analysis of the quality control samples showed good accuracy (96.7-100.42) and precision (RSD = 2,6-5,7%). The proposed method could be advantageous in estimation of doxorubicin incorporated into targeted delivery systems that concentrate in blood cells and quantify the absolute blood concentration of doxorubicin.Razvijena je i validirana brza i osjetljiva metoda visokotlačne tekućinske kromatografije (HPLC) s fluorimetrijskom detekcijom za određivanje doksorubicina u krvi psa. Nakon obrade uzoraka krvi koji sadrže doksorubicin s AgNO3 (taložno sredstvo za proteine), uz osnovni signal (tR = 5,5min) pojavljuje se dodatni signal u kromatogramu doksorubicina na 11,5 min. Nikakav dodatni signal se ne pojavljuje ako se za taloženje proteina upotrijebe trikloroctena kiselina ili metanol. Međutim, u hemoliziranim uzorcima plazme kojima je dodan doksorubicin nakon obrade sa srebrovim nitratom pojavljuje se drugi signal. Kalibracijska krivulja s površinom ispod signala za samo prvi pik (tR = 5,5min) nije linearna. Međutim, suma površina ispod prvog (tR = 5.5min) i drugog signala (tR = 11.5min) daje linearnu zavisnost s korelacijskim koeficijentom R2 = 0,9985. Pojava drugog signala mogla bi biti posljedica interakcije doksorubicina sa staničnim komponentama u krvi u prisutnosti AgNO3 te nastajanja kompleksa smanjene polarnosti. Površina ispod signala na kromatogramu određena na temelju fluorescencijske detekcije na 480 nm i 560 nm (valne duljine pobuđivanja, odnosno emisije) upotrebljena je za kvantitativnu analizu doksorubicina. Određivanje doksorubicina u krvi psa je jednostavna, precizna i točna. U svim eksperimentima, relativna standardna devijacija (RSD) najčešće je bila < 10%, a izmjerena i teorijska koncentracija razlikovala se za < 10%. Doksorubicin inkubiran s uzorcima krvi psa bio je stabilan najmanje 3 dana ako je čuvan na 5 °C, odnosno najmanje 8 h ako je čuvan na sobnoj temperaturi (28 °C). Predložena HPLC metoda mogla bi imati prednosti u određivanju doksorubicina u sustavima za isporuku lijekova ciljano u krvne stanice i kvantifikaciji ukupne koncentracije doksorubicina u krvi

Povećana isporuka etopozida u Daltonov limfom u miševa pomoću micela s polisorbatom 20

The study evaluates the possibility of enhancing uptake of etoposide (topoisomerase II inhibitor) by tumor when delivered through Polysorbate 20 micelles. The micelle formation was ascertained by determining the critical micellar concentration (CMC) with a du Nouy ring tensiometer and by size measurement using dynamic light scattering. Addition of 5% ethanol decreased the CMC of Polysorbate 20 (from 5.0 x 10-5 to 4.54 x 10-5 mol L-1). Etoposide (ET) and etoposide loaded Polysorbate 20 micelles (EPM) were radiolabeled with 99mTc by the reduction method using stannous chloride. Labeling parameters were optimized to obtain high labeling efficiency. The diethylenetriamine pentaacetic acid and cysteine challenge tests showed very low transchelation of 99mTc-ET and 99mTc-EPM complexes indicating their in vitro stability. The complexes also exhibited serum stability assessed by ascending thin layer chromatography. Subcutaneous injection of EPM resulted in significantly higher tumor uptake (~ 100 folds compared to ET 6 h post injection) (p < 0.001) and prolonged tumor retention. Tumor uptake was also confirmed by gamma imaging studies. EPM exhibited relatively high brain concentrations (~7 fold 24 h post injection) compared to ET, suggesting the potential use of EPM in the treatment of brain malignancies.U radu je proučavan ulazak etopozida (inhibitora topoizomeraze II) u tumorsko tkivo iz micela s polisorbatom 20. Oblikovanje micela je potvrđeno određivanjem kritične micelarne koncentracije (CMC) pomoću du Nouy kružnog tenziometra i mjerenjem veličine čestica metodom rasapa svjetlosti. Dodatak 5% etanola smanjuje CMC polisorbata 20 (od 5,0 x 10-5 do 4,54 x 10-5 mol L-1). Etoposid (ET) i micele etoposida s polisorbatom 20 (EPM) obilježene su radioizotopom 99mTc redukcijom pomoću kositrova klorida. Parameteri markiranja su optimirani. Testovi s dietilentriamin pentaoctenom kiselinom i cisteinom pokazali su vrlo nisko transkeliranje 99mTc-ET i 99mTc-EPM kompleksa, što ukazuje na njihovu stabilnost u uvjetima in vitro. Uzlaznom tankoslojnom kromatografijom dokazana je i stabilnost kompleksa u serumu. Nakon subkutane primjene EPM isporuka etopozida u tumorsko tkivo bila je značajno veća (~ 100 puta u odnosu na ET 6 h poslije injiciranja) (p < 0,001), a dokazano je i produljeno zadržavanje EPM u tumoru. Ulazak u tumor je potvrđen i gama analizom slike. EPM je postigao relativno visoku koncentraciju u mozgu u usporedbi s ET (~ 7 puta veću 24 h poslije injiciranja), zbog čega bi se potencijalno mogao upotrijebiti u terapiji malignih tumora mozga

Brza i osjetljiva HPLC metoda za određivanje doksorubicina u krvi psa Artifakt srebrovog nitrata

A rapid and sensitive high performance liquid chromatographic (HPLC) assay utilizing fluorimetric detection (excitation at 480 nm, emission at 560 nm) for the determination of doxorubicin in dog blood was developed and validated. Treatment of blood samples containing doxorubicin with AgNO3 (as protein precipitant) resulted in appearance of an additional peak in the chromatogram of doxorubicin at 11.5 min along with the parent peak (tR = 5.5 min). The latter peak was not found when treated with other protein precipitants such as trichloroacetic acid and methanol. Construction of calibration curve based on area of both peaks alone did not result in linearity of the curve. However, summation of areas of both peaks resulted in a curve with good linearity and correlation coefficient (R2 = 0.9985). Appearance of second peak may be due to the interaction of doxorubicin with cellular components of blood in the presence of AgNO3 leading to the formation of complex with reduced polarity. Analysis of the quality control samples showed good accuracy (96.7-100.42) and precision (RSD = 2,6-5,7%). The proposed method could be advantageous in estimation of doxorubicin incorporated into targeted delivery systems that concentrate in blood cells and quantify the absolute blood concentration of doxorubicin.Razvijena je i validirana brza i osjetljiva metoda visokotlačne tekućinske kromatografije (HPLC) s fluorimetrijskom detekcijom za određivanje doksorubicina u krvi psa. Nakon obrade uzoraka krvi koji sadrže doksorubicin s AgNO3 (taložno sredstvo za proteine), uz osnovni signal (tR = 5,5min) pojavljuje se dodatni signal u kromatogramu doksorubicina na 11,5 min. Nikakav dodatni signal se ne pojavljuje ako se za taloženje proteina upotrijebe trikloroctena kiselina ili metanol. Međutim, u hemoliziranim uzorcima plazme kojima je dodan doksorubicin nakon obrade sa srebrovim nitratom pojavljuje se drugi signal. Kalibracijska krivulja s površinom ispod signala za samo prvi pik (tR = 5,5min) nije linearna. Međutim, suma površina ispod prvog (tR = 5.5min) i drugog signala (tR = 11.5min) daje linearnu zavisnost s korelacijskim koeficijentom R2 = 0,9985. Pojava drugog signala mogla bi biti posljedica interakcije doksorubicina sa staničnim komponentama u krvi u prisutnosti AgNO3 te nastajanja kompleksa smanjene polarnosti. Površina ispod signala na kromatogramu određena na temelju fluorescencijske detekcije na 480 nm i 560 nm (valne duljine pobuđivanja, odnosno emisije) upotrebljena je za kvantitativnu analizu doksorubicina. Određivanje doksorubicina u krvi psa je jednostavna, precizna i točna. U svim eksperimentima, relativna standardna devijacija (RSD) najčešće je bila < 10%, a izmjerena i teorijska koncentracija razlikovala se za < 10%. Doksorubicin inkubiran s uzorcima krvi psa bio je stabilan najmanje 3 dana ako je čuvan na 5 °C, odnosno najmanje 8 h ako je čuvan na sobnoj temperaturi (28 °C). Predložena HPLC metoda mogla bi imati prednosti u određivanju doksorubicina u sustavima za isporuku lijekova ciljano u krvne stanice i kvantifikaciji ukupne koncentracije doksorubicina u krvi

A Validated Stability-Indicating RP-UPLC Method for Simultaneous Determination of Desloratadine and Sodium Benzoate in Oral Liquid Pharmaceutical Formulations

A novel, sensitive and selective stability-indicating gradient reverse phase ultra performance liquid chromatographic method was developed and validated for the quantitative determination of desloratadine and sodium benzoate in pharmaceutical oral liquid formulation. The chromatographic separation was achieved on Acquity BEH C8 (100 mm × 2.1 mm) 1.7 μm column by using mobile phase containing a gradient mixture of solvent A (0.05 M KH2PO4 and 0.07 M triethylamine, pH 3.0) and B (50:25:25 v/v/v mixture of acetonitrile, methanol and water) at flow rate of 0.4 mL/min. Column temperature was maintained at 40°C and detection was carried out at a wavelength of 272 nm. The described method shows excellent linearity over a range of 0.254 μg/mL to 76.194 μg/mL for desloratadine and 1.006 μg/mL to 301.67 μg/mL for sodium benzoate. The correlation coefficient for desloratadine and sodium benzoate was more than 0.999. To establish stability-indicating capability of the method, drug product was subjected to the stress conditions of acid, base, oxidative, hydrolytic, thermal and photolytic degradation. The degradation products were well resolved from desloratadine and sodium benzoate. The developed method was validated as per international ICH guidelines with respect to specificity, linearity, LOD, LOQ, accuracy, precision and robustness

Analysis of total knee replacements in a South Indian Institute

Background: Total knee replacement (TKR) is the most widely practised elective surgical procedure for advanced osteoarthritic patients globally. There is paucity of data on TKR’s in south Indian population. This study was aimed at analysing the peri-operative data of primary TKR’s to ease in customising the imported implants for our population.Methods: Data on 261 TKR’s performed in our institute over 40 months was collected. Categorical variables like age, gender, size of components used, co-morbidities and type of implants used were analysed.Results: Out of 220 patients with 261 knees, 141 were females (173 knees) and 79 were males (88 knees). The age group of the cohort was 60±11.2 years (Mean±SD). Diabetes and Hypertension (n=152) were the commonest co morbidities. The Cruciate Retaining (CR) type of prosthesis was used to the maximum extent (n=218). Size 3 femoral and tibial component was the commonly used in males and size 2 in females. 143(54.8%) knees had tibio-femoral component mismatch.  Conclusions: This study gives a reasonable insight into various aspects of the total knee replacements in a South Indian Institute. This data would be useful for manufacturing suitable implants customised for our population in the context of imported implants being in vogue. It also helps the operating surgeon to appropriately order for the desirable implants well in advance lest he should struggle intra operatively for want of better clinical outcome