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71.
Tushar Sharma Kevin Aroom Sahil Naik Brijesh Gill John X. J. Zhang 《Annals of biomedical engineering》2013,41(4):744-751
We demonstrate the design of thin flexible pressure sensors based on piezoelectric PVDF-TrFE (polyvinyledenedifluoride-tetrafluoroethylene) co-polymer film, which can be integrated onto a catheter, where the compact inner lumen space limit the dimensions of the pressure sensors. Previously, we demonstrated that the thin-film sensors of one micrometer thickness were shown to have better performance compared to the thicker film with no additional electrical poling or mechanical stretching due to higher crystallinity. The pressure sensors can be mass producible using standard lithography process, with excellent control of film uniformity and thickness down to one micrometer. The fabricated pressure sensors were easily mountable on external surface of commercial catheters. Elaborate experiments were performed to demonstrate the applicability of PVDF sensors towards catheter based biomedical application. The resonant frequency of the PVDF sensor was found to be 6.34 MHz. The PVDF sensors can operate over a broad pressure range of 0–300 mmHg. The average sensitivity of the PVDF sensor was found to be four times higher (99 μV/mmHg) than commercial pressure sensor while the PVDF sensor (0.26 s) had fivefold shorter response time than commercial pressure sensor (1.30 s), making the PVDF sensors highly suitable for real-time pressure measurements using catheters. 相似文献
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D. Sahoo P. Priyadarshini A. Aparimita D. Alagarasan R. Ganesan S. Varadharajaperumal R. Naik 《RSC advances》2020,10(45):26675
The present work shows the effect of annealing conditions on the linear and nonlinear optical properties of two-year-old thermally evaporated 800 nm As40Se50Ge10 thin films. The aging effect in this film is clearly noticeable as compared with the old observation. The two-year-old films were annealed at different temperatures like 373, 413, 453 and 493 K for 1 h. The optical parameters were calculated from the optical transmittance and reflectance spectra measured at normal incidence of light by spectrometer in the 500–1000 nm range. The linear refractive index (n) and extinction coefficient (k) were decreased with annealing temperature. The observation reveals the increase in optical band gap with increase in annealing temperature while the width of the tail in the gap has an opposite behaviour. The oscillator energy, dispersion energy, dielectric constant, the loss factor, and optical conductivity were discussed in detail. The nonlinear refractive index and optical susceptibility were calculated by using Miller''s formula which decreased with annealing temperature. The changes in both linear and nonlinear optical parameters with annealing temperature showed that annealing temperature can be considered as a useful factor for controlling the optical properties of As40Se50Ge10 chalcogenide films which could be the candidate for numerous photonic applications. The structural study was done by X-ray diffraction and Raman spectroscopy.The present work shows the effect of annealing conditions on the linear and nonlinear optical properties of two-year-old thermally evaporated 800 nm As40Se50Ge10 thin films. 相似文献
74.
Kapil S. Agrawal Manoj V. Bachhav Charudatta S. Naik Shikha Gupta Anup V. Sarda Vyoma Desai 《Indian Journal of Plastic Surgery》2015,48(2):172-177
Augmentation rhinoplasty can be carried out using a wide range of materials including autologous bone and/or cartilage as well as alloplasts. Use of biologic bone and cartilage grafts results in lower infection rates, but they are associated with long-term resorption and donor-site morbidity. Alloplastic materials, in particular silicone, have been associated in literature with extrusion, necrosis of the tip, mobility and deviation or displacement of the implant, immobile nasal tip and infection. However, they have the advantages of being readily available and easy to reshape with no requirement for harvesting autografts.
Aim:
To overcome these problems associated with silicone implants for which the authors have devised a novel technique, the “rideon technique”.Materials and Methods:
The present study was carried out on 11 patients over a period of 4 years. The authors have devised a simple technique to fix the silicone implant and retain it in place. Restricting the implant to only dorsum avoided common complications related to the silicone implant.Results:
The authors have used this technique in 11 patients with encouraging results. Follow-up ranged from 12 months to 36 months during which patients were assessed for implant mobility, implant extrusion and tip necrosis. There was no incidence of above mentioned complications in these patients.Conclusion:
The “rideon technique” provides excellent stability to silicone implants and restricting the implant only to dorsum not only eliminates chances of tip necrosis and thus implant extrusion but also maintains natural shape, feel and mobility of the tip.KEY WORDS: Alloplasts, autografts, rhinoplasty, silicone implants 相似文献75.
76.
Magnetic Resonance Imaging and Localized In Vivo Proton Spectroscopy in Patients with Fulminant Hepatic Failure 总被引:1,自引:0,他引:1
R. K. Gupta M.D. V. A. Saraswat M.D. H. Poptani R. K. Dhiman M.D. A. Kohli M.D. R. B. Gujral S. R. Naik M.D. 《The American journal of gastroenterology》1993,88(5):670-674
Magnetic resonance imaging (MRI) and in vivo proton spectroscopic changes in the brain in three patients with fulminant hepatic failure are described. MRI showed cerebral atrophy in two and changes somewhat similar to what have been described in chronic hepatic encephalopathy. MR spectroscopy showed low myoinositol with high glutamine in grade IV coma, which returned to normal as patient showed clinical recovery. We conclude that these techniques will be useful in understanding the complex pathophysiology of fulminant hepatic failure. 相似文献
77.
S Sarkar P Mookerjee A Roy T N Naik J K Singh A R Sharma Y I Singh P K Singh S P Tripathy S C Pal 《The Journal of infection》1991,23(2):201-207
India is considered to have a low incidence of HIV infection so far. Nevertheless, an epidemic of HIV infection has been reported recently among intra-venous drug users (IVDUs) in Manipur, a north-eastern state of India, bordering Myanmar (Burma). This report describes the epidemiology of intravenous drug abuse in the state of Manipur. Four hundred and fifty IVDUs were interviewed. Their age (median 24 years) and sex patterns (95% male) differ from those reported from western countries. It is estimated that there may be approximately 15,000 such addicts in a population of 1.8 million and 50% of them could be positive for HIV. Knowledge of AIDS and its transmission is significantly higher among the addicts than non-addict controls. Free availability of heroin was found to be the major factor responsible for the high rate of addiction. It is presumed that two other neighbouring States which are well-connected to Manipur and also have a common border with Myanmar (part of the 'Golden Triangle') may have a similar problem with HIV infection. 相似文献
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80.
Shweta Naik Jyoti Sharma Rameshwor Yengkom Vijay Kalrao Atul Mulay 《Indian Journal of Critical Care Medicine》2014,18(3):129-133