Papers by Rajesh Vishwakarma
International Journal of Head and Neck Surgery, 2010
Foreign body impaction in the neck poses life-threatening problems when it is deep and close to v... more Foreign body impaction in the neck poses life-threatening problems when it is deep and close to vital structures. We report two cases of sharp metallic foreign body impaction in the neck -one of them in the prevertebral space and the other in the intervertebral disk space. A neck exploration and surgical removal of these foreign bodies, as is usually practised in most centers, would have been life-threatening and associated with high morbidity. We removed these foreign bodies using rigid endoscope under image intensified television (IITV) guidance. The patients could be discharged the same day. We suggest that endoscopic removal under IITV fluoroscopy system should be the method of choice in the removal of foreign bodies located in these sites. We also propose a classification of neck into vertical segments which would be useful in the management decision of these cases.
Cochlear Implants International, 2009
Delayed facial nerve palsy following cochlear implant surgery is less documented though it poses ... more Delayed facial nerve palsy following cochlear implant surgery is less documented though it poses diagnostic and therapeutic challenges. Apart from the functional, aesthetic and emotional concerns, it can raise important medico legal issues. The objectives of this study were: to report a case of delayed facial palsy following cochlear implant surgery in a patient who had positive viral antibody markers pre operatively; and to review the literature on delayed onset facial paralysis following viral reactivation and its relation to cochlear implant surgery. An extensive literature review was done using internet and medical search engines and library facilities. Important articles on the topic were identified and summarised. Data on delayed facial palsy following cochlear implant surgery were collected, constructed in a coherent way and details discussed. Postulated mechanisms of delayed facial palsy include neural oedema, vasospasm and viral reactivation. Of these, reactivation of previous herpes simplex virus infection has special significance, as many of these patients are positive for viral antibody markers. Manipulation of sensory branches of the facial nerve and chorda tympani can be a mechanism in such cases. Correlation of clinical presentation and pre operative positive viral antibody markers with positive polymerase chain reaction can be strongly suggestive of viral reactivation. It is concluded that patients with positive viral antibody markers are more susceptible to facial palsy from viral reactivation. Corticosteroids, antiviral agents and physiotherapy can be useful in producing a quicker and complete recovery. An experienced cochlear implant surgery team and pre operative radiological evaluations are mandatory to decrease the chances of direct facial nerve trauma. Proper irrigation lowers the risk of neural oedema. Copyright © 2009 John Wiley & Sons, Ltd.
American Journal of Otolaryngology, 2009
Incudostapedial joint dislocation is the most frequently found ossicular chain defect. In these c... more Incudostapedial joint dislocation is the most frequently found ossicular chain defect. In these cases reconstitution of joint capsule is important in maintaining joint integrity. But reconstruction of dislocated incudostapedial joint is a challenging procedure as this joint is devoid of any muscular or soft tissue support. Here we describe a technique designed to reposition the incudostapedial joint in its anatomical position using temporalis fascia or perichondrium. Data have been collected and analyzed from 42 patients with incudostapedial joint discontinuity. The fascial ties used for reconstruction of joint capsule ensure a dynamic union of the repositioned incus with stapes, leading to a significant improvement in conductive hearing loss.
International Journal of Head and Neck Surgery, 2010
Foreign body impaction in the neck poses life-threatening problems when it is deep and close to v... more Foreign body impaction in the neck poses life-threatening problems when it is deep and close to vital structures. We report two cases of sharp metallic foreign body impaction in the neck -one of them in the prevertebral space and the other in the intervertebral disk space. A neck exploration and surgical removal of these foreign bodies, as is usually practised in most centers, would have been life-threatening and associated with high morbidity. We removed these foreign bodies using rigid endoscope under image intensified television (IITV) guidance. The patients could be discharged the same day. We suggest that endoscopic removal under IITV fluoroscopy system should be the method of choice in the removal of foreign bodies located in these sites. We also propose a classification of neck into vertical segments which would be useful in the management decision of these cases.
Cochlear Implants International, 2009
Delayed facial nerve palsy following cochlear implant surgery is less documented though it poses ... more Delayed facial nerve palsy following cochlear implant surgery is less documented though it poses diagnostic and therapeutic challenges. Apart from the functional, aesthetic and emotional concerns, it can raise important medico legal issues. The objectives of this study were: to report a case of delayed facial palsy following cochlear implant surgery in a patient who had positive viral antibody markers pre operatively; and to review the literature on delayed onset facial paralysis following viral reactivation and its relation to cochlear implant surgery. An extensive literature review was done using internet and medical search engines and library facilities. Important articles on the topic were identified and summarised. Data on delayed facial palsy following cochlear implant surgery were collected, constructed in a coherent way and details discussed. Postulated mechanisms of delayed facial palsy include neural oedema, vasospasm and viral reactivation. Of these, reactivation of previous herpes simplex virus infection has special significance, as many of these patients are positive for viral antibody markers. Manipulation of sensory branches of the facial nerve and chorda tympani can be a mechanism in such cases. Correlation of clinical presentation and pre operative positive viral antibody markers with positive polymerase chain reaction can be strongly suggestive of viral reactivation. It is concluded that patients with positive viral antibody markers are more susceptible to facial palsy from viral reactivation. Corticosteroids, antiviral agents and physiotherapy can be useful in producing a quicker and complete recovery. An experienced cochlear implant surgery team and pre operative radiological evaluations are mandatory to decrease the chances of direct facial nerve trauma. Proper irrigation lowers the risk of neural oedema. Copyright © 2009 John Wiley & Sons, Ltd.
American Journal of Otolaryngology, 2009
Incudostapedial joint dislocation is the most frequently found ossicular chain defect. In these c... more Incudostapedial joint dislocation is the most frequently found ossicular chain defect. In these cases reconstitution of joint capsule is important in maintaining joint integrity. But reconstruction of dislocated incudostapedial joint is a challenging procedure as this joint is devoid of any muscular or soft tissue support. Here we describe a technique designed to reposition the incudostapedial joint in its anatomical position using temporalis fascia or perichondrium. Data have been collected and analyzed from 42 patients with incudostapedial joint discontinuity. The fascial ties used for reconstruction of joint capsule ensure a dynamic union of the repositioned incus with stapes, leading to a significant improvement in conductive hearing loss.
International Journal of Food Science and Technology, 2009
In this study, hulling efficiency and hulling losses were optimised for pigeonpea. Effects of hul... more In this study, hulling efficiency and hulling losses were optimised for pigeonpea. Effects of hulling time, moisture content and cottonseed oil as pre-milling agent were studied and optimised using response surface methodology. A quadratic model satisfactorily described the hulling efficiency with an R2 value of 0.93. It predicted maximum dehulling efficiency of 89.98% at 9.82% moisture content (wet basis), 12.05-s time of hulling and 0.28% cottonseed oil treatment. Linear model developed for hulling loss showed significant effect of time of hulling whereas effect of oil treatment and moisture content were non-significant. The model predicted hulling loss of 2.92% on optimum conditions. The results of the model were validated experimentally and were within the range.
Food and Bioprocess Technology, 2010
Pitting is a premilling operation in which pigeon pea grain is passed through a dehulling machine... more Pitting is a premilling operation in which pigeon pea grain is passed through a dehulling machine quickly to crack the hull or partly dehull the grain. A study was conducted to investigate the effect of grain moisture content on pigeon pea hull during pitting. Pitting of the grain was done at 6%, 8%, 10%, 12%, and 14% moisture contents using dhal mill developed by Central Institute of Agricultural Engineering, Bhopal (India). Grains having a cracked hull or partly dehulled during pitting varied from 35.3% to 85.3% with maximum value at 10% moisture content and reduced with an increase in moisture content. Maximum finished product in the form of dehulled whole (gota) and dehulled splits (dhal) was also obtained at 10% moisture content. Pitted grains of pigeon pea were treated with 0.28% cottonseed oil to study the effect of moisture content and pitting on dehulling efficiency, which was maximum (86.7%) at 10% moisture content.
Biosystems Engineering, 2008
Dehulling efficiency and loss were optimised for pigeon pea. The effects of dehulling time, moist... more Dehulling efficiency and loss were optimised for pigeon pea. The effects of dehulling time, moisture content and the use of mustard oil as a pre-milling treatment agent were studied and optimised using response surface methodology. A quadratic model satisfactorily described the dehulling efficiency with high value for the coefficient of determination R 2 (0.95) values. It predicted a maximum dehulling efficiency of 83.2% at 10.1% moisture content, 12.3 s. dehulling time and 0.3% mustard oil treatment. Moisture content and dehulling time affected dehulling loss significantly whereas the effect of mustard oil treatment was non-significant. A dehulling loss of 2.5% was predicted at optimum conditions. The results of the predicted optimum conditions were validated experimentally. Dehulling efficiency and loss at optimum conditions were observed to be 82.470.8% and 3.170.4%, respectively, and were close to the predicted values.
Microstrip antenna consists of a radiating patch on one side of dielectric substrate which has a ... more Microstrip antenna consists of a radiating patch on one side of dielectric substrate which has a ground plane on the other side. The antenna element it self may be square, rectangular, circular, triangular etc and may have more than one feed. An experimental study of dual band characteristics of single layer rectangular microstrip antenna is presented. For feeding of the antenna direct microstrip coupling with proper matching transformer has been used. The optimized notch dimension has been taken for two resonant frequencies. The resonance frequency changes with the variation in the length and width of the notch. The VSWR is measured with the help of network analyzer.
The analysis of single patch microstrip antenna based on impedance model, emphasizing mainly on t... more The analysis of single patch microstrip antenna based on impedance model, emphasizing mainly on the design considerations for dual-band and dual-polarization, is presented here. A length compensation technique is proposed to achieve the exact dual mode resonance with desired accuracy. The proposed method provides serval alternative dimensions (lengths) of the patch which could be utilized to develop the dual-band, dualpolarization antenna.
A dual-band characteristic of single layer stacked rectangular microstrip antenna is experimental... more A dual-band characteristic of single layer stacked rectangular microstrip antenna is experimentally studied. The variations of the length and width of the stacked rectangular patch antenna has been done and found dual resonance with increasing lower resonance frequency and almost constant upper resonance frequency with increases of the length & width of rectangular microstrip antenna. The VSWR has been measured with the help of Network analyzer
The series and shunt inductivity introduced by the probe and shorting pin respectively in a singl... more The series and shunt inductivity introduced by the probe and shorting pin respectively in a single-feed shorted rectangular microstrip antenna has been evaluated theoretically using transmission line method. The proposed structure provides compact dual band operation using single feed mechanism. The input impedance, VSWR, and return loss are calculated theoretically. It is found that the ratio of the resonant frequencies highly depends on the position of shorting pin.
A dual-band characteristic of stacked rectangular microstrip antenna is experimentally studied. I... more A dual-band characteristic of stacked rectangular microstrip antenna is experimentally studied. It is a probe fed antenna for impedance matching with 50Ω coaxial cable. This antenna works well in the frequency range 2.86-4.63 GHz. It is basically a low cost, light weight medium gain antenna which is used for mobile communication. The variations of the length and width (1 mm) of the stacked rectangular patch antenna have been done. It is found to have dual resonance with increasing lower resonance frequency and almost constant upper resonance frequency with increases of the length and width of rectangular microstrip antenna. The input impedance and voltage standing wave ratio (VSWR) return loss have been measured with the help of network analyzer.
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Papers by Rajesh Vishwakarma