Surfing the High Energy Output Branch of Nonlinear Energy Harvesters.

Hysteresis and multistability are fundamental phenomena of driven nonlinear oscillators, which, however, restrict many applications such as mechanical energy harvesting. We introduce an electrical control mechanism to switch from the low to the high energy output branch of a nonlinear energy harvester by exploiting the strong interplay between its electrical and mechanical degrees of freedom. This method improves the energy conversion efficiency over a wide bandwidth in a frequency-amplitude-varying environment using only a small energy budget. The underlying effect is independent of the device scale and the transduction method and is explained using a modified Duffing oscillator model.

Tubercular breast abscess--a diagnostic dilemma.

Tuberculosis affects many organs, however isolated tubercular breast lesion is rare. Clinically as well as radiologically it may mimic both pyogenic abscess and malignancy. One such case is being reported where a middle aged woman presented with painful, gradually increasing breast lump and was diagnosed clinically, radiologically, cytologically and even histologically as pyogenic abscess. Poor response to antibiotics raised the suspicion of malignancy for which repeat fine needle aspiration cytology was done. Well formed granulomas, necrosis and finally demonstration of acid fast bacilli established the diagnosis of tubercular abscess. No other organs were involved by tuberculosis in this case. Patient responded well to antitubercular drugs. Thus diagnostic challenge lies in the demonstration of acid fast bacilli in cases of equivocal morphology in routine cytology as well as histology. High clinical suspicion, poor response to antibiotics, suggestive radiological findings, cytology, histology and demonstration of acid fast bacilli -all contributes to the diagnosis of breast tuberculosis.

Leiomyoma of broad ligament mimicking ovarian malignancy- report of a unique case.

Tumors of the broad ligament are uncommon. Leiomyoma, which is the commonest female genital neoplasm, is also the most common solid tumor of the broad ligament. Leiomyomas affect 30% of all women of reproductive age but the incidence of broad-ligament leiomyoma is <1%. These benign tumors are usually asymptomatic. A case is being described where a 52 year old presented with gradual abdominal swelling which was clinically and radiologically diagnosed as ovarian malignancy. On abdominal and bimanual palpation a soft cystic mass was noted in the right pelvic region. CA 125 was mildly raised. CEA, CA 19.9 levels were within normal limit. The radiological diagnosis was ovarian cyst with possibility of malignant changes. Staging laparotomy and histopathological examination of the resected specimen revealed a right sided broad ligament leiomyoma with cystic changes. The degenerative changes in the leiomyoma lead to the clinical and radiological diagnostic confusion. Thus, though uncommon, broad ligament leiomyoma should be considered during evaluation of adnexal masses for optimal patient management. The above description of leiomyoma in the broad ligament is a highly unique case and thus deserves appropriate attention.

Waardenburg syndrome associated with laryngomalacia.

Waardenburg syndrome (WS) is a rare autosomal dominant condition characterised by sensorineural hearing loss, in conjunction with pigmentary abnormalities and defects of the neural crest-derived tissues. Depending on the additional phenotypic characteristics, WS is classified into four types, viz. WS1, WS2, WS3 and WS4. We report a 45-day-old male infant with WS1, who presented with inspiratory stridor associated with difficulty in respiration. Direct flexible laryngoscopic examination during evaluation confirmed laryngomalacia as the cause of the symptoms. The baby was managed conservatively and was discharged with appropriate advice to the mother, including the need for evaluation at regular intervals. There was gradual improvement in his symptoms, and by one year of age, he was completely symptom free. To our knowledge, laryngomalacia as a part of WS has not been documented to date in the English literature. We also briefly discussed the probable embryological basis for the observed association.

Studies on commuters' exposure to BTEX in passenger cars in Kolkata, India.

Commuters' exposure to volatile organic compounds (VOCs) especially BTEX travelling in passenger cars in Kolkata, India were quantified in Phase I (2001-2002) and Phase II (2003-2004). Monitoring was made inside and in the immediate outside of passenger cars fitted with and without catalytic converters using different types of fuels, along two congested urban routes. During Phase I of the study, the benzene content in gasoline was 5% and the mean concentration of in-vehicle benzene in cars without catalytic converter was found to be as high as 721.2 microg/m3. In Phase II when the benzene content was reduced to <3% and with modified engine type, the mean in-vehicle benzene concentration was reduced to 112.4 microg/m3. The in-vehicle concentration varied with engine type and age of the vehicle. Roadside ambient mean concentration of benzene was 214.8 microg/m3 and 30.8 microg/m3 in Phase I and Phase II respectively.