Varying Vector Pulse Width Modulation for Three Phase Inverter

This paper mainly deals with designing a control scheme to eliminate the OFF STATE (T0 state) present in a Space Vector Pulse-Width Modulation; this has been achieved by redesigning the equations for calculating the reference vector of modulating signal (Vref). In widely used Space Vector Pulse Width Modulation Vmax of carrier signal is greater than Vref of modulating signal (except when Vref = Vmax). Thus during this state the drive goes into the OFF STATE (T0 state). T0 States are similar mirror image states; hence they have no good or bad effect on the system. But there is an amount of switching loss occurring when the switch executes the T0 state. The new equations for reference vector resulted in reducing the switching losses to half the actual value. Also it has various other advantages like. Increase in DC-Link utilization from 15.47 to 21.14 at 2 KHz carrier frequency and Reduction in THD of the system compared to widely used SVPWM

Formulation and Optimization of Floating Drug Delivery System Oflevofloxacin Hemihydrate

AIM AND OBJECTIVES: Levofloxacin is a synthetic flouroquinoline antibacterial agent that inhibits bacterial DNA replication. It is L-isomer of Ofloxacin. It has a half life of 6hrsand the absorption of Levofloxacin is dose dependant, which increases with increase in dose. It is used in treating various infections caused by microorganisms like bacillus anthracis, Chlamydia infection, cystitis, epidydimitys, gonorrhea etc. The dose ranges from 250mg to 750mg.It is first choice drug used for treatment of Helicobacter pylori infections. Floating drug delivery system of Levofloxacin hemihydrates can localize the drug action within the stomach to treat gastric ulcers caused by Helicobacter pylori. In the present study, natural polymers such as gum kondagogu, gum karayaandxanthumgum are selected for the preparation of floating tablets of Levofloxacin hemihydrates. Sodium bicarbonate was used as gas generating agent. Tablets were prepared by wet granulation method using these polymers. The main objectives of this investigation are as follows: 1. To isolate and extract natural polymers from their natural sources. 2. To study the effect of sodium bicarbonate concentration and to optimize the concentration of gas generating agent. 3. To conduct the compatibility studies of Levofloxacin hemihydrates with natural polymers by IR spectral studies. 4. To formulate and evaluate Levofloxacin hemihydrate extended release floating tablets by Wet granulation method. 5. To evaluate the formulated tablets according to the pharmacopeia standards.6. To study the influence of natural polymers on release rate and to select the best release retarding polymer among them. 7. To conduct comparative release studies among the natural polymers. 8. To evaluate the mechanism and release kinetics of drug from the prepared tablets. SUMMARY AND CONCLUSION: Floating tablets of Levofloxacin hemihydrate prepared usinggumkaraya, xanthumgumandgumkondagogu showed controlled release for a prolonged period of time. The natural polymers used showed drug release retarding nature and the release retarding nature was in order of Xanthum gum> gum kondagogu> gum karaya. Compared to other gums used Xanthumgumhashigh viscosity value and good drug release retarding capacity. There is a similarity between the viscosities of the polymers and their release retarding profiles. The floating tablets prepared only with HPMC K 100 M had shown much lesser drug release than the combination of natural polymer (gum kondagogu/ gum karaya) and HPMC K 100 M.Whereas in case of formulations prepared with xanthum gum and HPMC K 100 M shows much lesser drug release than the formulations prepared with HPMC K 100 M alone. The concentration of NaHCO 3 influences the lag time. In this investigation 20-23% NaHCO 3 was selected as optimized concentration. The FT-IR studies clearely indicates that there are no drug and polymer interactions. PreparedLevofloxacin hemihydrate floating tablets complies with the specifications of the Pharmacopoeial standards. From this study it could be concluded that natural polymers can be used in the preparation of floating tablets and in combination with synthetic polymers. Floating tablets of Levofloxacin hemihydrate prepared by employing natural polymers could be used for treatment of gastric ulcers caused by H.pylorii infection by prolonging the gastric residence time and its controlled release in the gastric environment thus completely eradicating the Helicobacter pylorifrom GIT

DRY EYE (SHUSHKAKSHIPAKA) AND MENOPAUSE – A SURVEY STUDY

Dry eye occurs when there is inadequate tear volume or function resulting in an unstable tear film and ocular surface disease. It is extremely common condition, particularly in postmenopausal women and the elderly. Although epidemiological studies investigating the prevalence of dry eye disease are rare, published studies indicate that up to 20% of adults aged 45 years or more experience dry eye symptoms. Menopause is permanent cessation of menstruation at the end of reproductive life which is the natural biological process. During this period there is gradual progressive loss of ovarian follicular activity. The increase incidence of dry eye in males than in females shows a positive impact stating there is hormonal impact on the disease. Androgens are the prime hormones responsible for regulation of lipid production. Oestrogen and progesterone receptors in the conjunctiva and lacrimal glands are essential for the normal function of these tissues. In Ayurveda, the disease comes under Sarvagata Roga and is named as Shushkakshipaka where in there will be depletion of Ashru leading to Shushka netra, which afflicts whole eye in the later stages. In menopausal women there will be Rasakshaya leading to Vata vriddhi. This impairs the normal functioning of the Netra where in the Shushkata will increase leading to many other symptomatology. To elucidate the relationship between menopause and dry eye, a survey study has been conducted in OPD and IPD of Sri Kalabyraweshwaraswamy Ayurvedic medical college, hospital and research centre, Bangalore which is affirmed

Dent-O-Myths Amid Young Community: A Cross-Sectional Study

INTRODUCTION: The word ‘Myth’ is derived from the Greek word “Mythos”, meaning the stories passed by a group of certain population having a strong impact on seeking general and dental treatment even during illness. AIM: The aim of this study was to access the prevalence of dental myths among the young population and to interpret their level of knowledge, awareness and perception. MATERIALS AND METHOD: A cross-sectional questionnaire survey was conducted amongst 500 young population of age between 18-28 years between May to August 2020, COVID-19 pandemic period. A pretested validated questionnaire was formatted on Google forms and circulated in various social media platforms. The collected data was subjected to statistical analysis. RESULTS: The mean age of the study population was 22.66±2.38 years, and 59% were females and 41% were males. About 65% (325) and 56% (280) of the study subjects believed correctly that mouthwash alone will not maintain oral health and chewing gum will not clean their teeth, respectively. When asked about their responses in case of pain in oral cavity, most people 46% (230) reported they would visit a dentist and major segment of study subjects 56% (281) believed that there can be more methods for treating oral pain other than the extraction of the tooth itself.CONCLUSION: The result of this study revealed that the younger population are more aware and didn’t believe much regarding various dental myths

ENERGY EFFICIENT ADAPTIVE BROADCASTING SCHEME FOR WIRELESS SENSOR NETWORKS

ABSTRACT Energy-efficiency is a critical issue in wireless sensor networks (WSNs), since sensors are battery operated with limited life time. Energy efficient broadcasting will have a direct impact on network lifetime. Since the minimum energy broadcasting schemes are affected by broadcast storm problem, it has to be addressed to improve the energy efficiency. To overcome the broadcast storm problem, probabilistic schemes have been proposed in the literature to make a rebroadcast decision. However, the random assessment delay (RAD) in probabilistic broadcasting schemes results in poor reachability and increased end to end delay in the congested networks. In the proposed work, the probabilistic scheme adapts its RAD based on network congestion level. The simulation results reveals that the new scheme outperforms the existing schemes in term of saved-rebroadcast, packet delivery and routing overhead

PRELIMINARY PHYTOCHEMICAL SCREENING AND ANTIBACTERIAL EFFICACY STUDIES OF ANNONA SQUAMOSA FRUIT

Objective: The present study was designed to evaluate the antimicrobial activity of lyophilized powder of Annona squamosa fruit. Phytochemical screening was carried out to detect the presence of major phytoconstituents. Methods: Annona squamosa fruit pulps were lyophilized and made into powder, which was diluted with 0.1% DMF. This extract was tested against gram positive and gram negative bacteria employing Agar well diffusion method. Results: The results showed that fruit extract possess antimicrobial activity against microbial isolates. The antibacterial activity increased with increase in mass of fruit extract, which was evidenced through zone of inhibition. The fruit extract showed significant activity when compared with standard positive antibiotic viz. Chloramphenicol (10 µg /disc). The preliminary phytochemical screening tests confirmed the presence of compounds such as alkaloids, terpenoids, flavonoids, steroids, saponins and glycosides as major constituents. Conclusion: Based on the results it is concluded that Annona squamosa has good antimicrobial activity against human pathogens and is also rich in phytochemical constituents