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This paper develops a seven-level inverter structure for open-end winding induction motor drives. The inverter supply is realized by cascading four two-level and two three-level neutral-point-clamped inverters. The inverter control is designed in such a way that the common-mode voltage (CMV) is eliminated. DC-link capacitor voltage balancing is also achieved by using only the switching-state redundancies. The proposed power circuit structure is modular and therefore suitable for fault-tolerant applications. By appropriately isolating some of the inverters, the drive can be operated during fault conditions in a five-level or a three-level inverter mode, with preserved CMV elimination and dc-link capacitor voltage balancing, within a reduced modulation range. Index Terms--Capacitor voltage balancing, common-mode voltage (CMV) elimination, multilevel inverter, open-end winding induction motor.

In this paper, a 12-sided polygonal voltage space vector generation with common-mode voltage elimination (CME) is proposed for an induction motor drive. An open-end winding configuration is used for the motor. The proposed multilevel structure is achieved by cascading only the conventional two-level inverters with asymmetrical dc link voltages. By appropriately selecting the voltage vectors with identical common-mode voltage from the opposite ends, a pulsewidth modulation (PWM) strategy with zero common-mode voltage variation can be achieved for the entire modulation range with a common dc link requirement for both the inverter systems. Along with the CME, the proposed 12-sided polygonal space vector based multilevel inverter structure has increased modulation range with the absence of 5th, 7th, 17th, 19th, etc., harmonics up to 12-step operation. The bandwidth problems associated with conventional hexagonal voltage space vector structure current controllers due to the presence of 5th and 7th harmonics in the overmodulation region are absent in the present 12-sided structure. So a simple PWM voltage control with linear voltage control up to 12-step operation is possible from the present 12-sided scheme with less current control complexity. Index Terms--Common-mode voltage elimination (CME), multilevel inverter, polygonal voltage space vector.

The paper presents a five-level inverter scheme with reduced power circuit complexity for an induction motor drive. The scheme is realized by cascading conventional two-level and three-level neutral point clamped inverters in conjunction with an open-end winding three-phase induction motor drive. An inverter control scheme with common-mode voltage (CMV) elimination, along with a simple dc link voltage control, is developed by using only switching states with zero CMV for the entire modulation range. Theoretical considerations are experimentally verified for a variety of operating conditions. Index Terms--Common-mode voltage (CMV) elimination, induction motor drives, multilevel inverter, open-end winding structure.

Introduction: The study of morphometry of menisci of the knee joint will provide data to meniscal anatomy in the native population,which is necessary for various surgical procedures and also for arthroscopy of the knee joint. To study the morphometric parameters of menisci of knee joint including their shape,breadth and thickness of, distance between their anterior and posterior horns and outer and inner circumferential length of each meniscus. Methods & Materials : The study was carried out in the Department of Anatomy of Institute of Post Graduate Medical Education &Research(IPGME&R),Kolkata,in cadavers donated to the department during a period of one year. Subjects having no mcroscopic deformities of their knee joints and ages ranging between 30 years to 60 years were only chosen . 50 knee joints belonging to 25 cadavers matching the above criteria were dissected for the study.Data analysis was done at IPGME&R, Kolkata and NRS Medical College, Kolkata. Observations &Results : Lateral Meniscus(LM) studied were found to be "circular" and all of the Medial meniscus(MM) studied were found to be "oval" in shape., The mean inter horn distance in case of LM was measured as 12.72mm and the same for MM was recorded as 29.02mm..The mean inner circumferential length of the LM of Left side was measured to be 43.49mm and the same for Right side was 43.68mm. Conclusion :This study will enrich the literature regarding the morphometry of the menisci and will also help to understand the mechanisms behind their injury. [ABSTRACT FROM AUTHOR]

Introduction: Placenta maintains a vital connection between the fetus and the mother. Nowadays it is proved that placenta has a remarkable reserve capacity to withstand noxious environment, but some of the detrimental factors, especially maternal anemia may have adverse effects on placenta which might compromise with the fetal well-being. Aims & Objectives: The present study seeks to look for the histological changes of placenta in maternal anemia. Materials & Methods: The study was conducted on pregnancy cases delivered in North Bengal Medical College & Hospital, Darjeeling. Cases of pregnancy with clinical and hematologically diagnosed anemia were taken as 'test-group' whereas those without evidence of anemia were taken as 'control' group. Placentas were procured, processed for microscopy and subjected to examination using light microscopy of relevant sections stained with hematoxylin and eosin. Results : Evidences of fibrinoid necrosis, hyalinized villous spots and villous fibrosis could be detected significantly more obviously in placentas of test-group than in control group. The intervillous spaces were found to be increased in anemic mothers in an attempt to compensate for low oxygen tension. Significantly larger areas of placental slides exhibited intervillous thrombosis in anemic mothers suggesting enhanced thromboplastin activities in the damaged syncytial site. The thrombosis could be associated with elevated maternal alfa-fetoprotein level. Conclusion: We concluded that placenta has considerable functional reserve capacity to repair any damage it suffers; it shows compensatory mechanisms to limit the ill-effects of unfavorable maternal milieu like anemia. Our findings were in accordance with the previous studies in this field. [ABSTRACT FROM AUTHOR]

Patellar height is one of the important parameter in patellar stability. Growth spurt or excessive physical strain can lead to high-riding patella or patella alta. But this is not yet proved. This study was mainly targeted at eliciting the influence of age on Insall-Salvati index, one of the important index to measure patellar height. As the present study is meant for measuring the patellar height separately in male and female, it is also to find out the effect of gender on patellar height if any. The study was been conducted in North Bengal Medical College and Hospital among 93 subjects covering both adult and adolescent age groups. Patellar height of respective subjects was measured radiologically using Insall-Salvati Index; results were extrapolated for statistical analysis. It revealed that value of Insall-Salvati index was higher in adult compared to adolescent group but the difference was not statistically significant. Statistical tests shows no significant difference in Insall-Salvati index according to sex. While screening the athletes patella alta must be kept in mind as this can be associated with patellofemoral pain syndrome, chondromalacia patellae, knees with apophysitis of tibial tubercle (Osgood-Schiatter disease). Not only that, significant cause of recurrent patellar dislocation can be associated with patella alta