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Biomedical subjects

N A Bhat

Publications and source records attributed to N A Bhat.

14 recordsLinked to original sources
PubMed2001

Optical pulse propagation in nonlinear photonic crystals.

We present a formalism for optical pulse propagation in nonlinear photonic crystals of arbitrary dimensionality. Using a multiple-scale analysis, we derive the dynamical nonlinear Schrödinger equation obeyed by the envelope function modulating an underlying Bloch function. Effective coefficients appear in that equation characterizing the effects of Kerr nonlinearity, linear gain or loss, and material dispersion. They depend on how the underlying Bloch function "samples" these effects in the photonic crystal, and require for their calculation a specification of these effects throughout the photonic crystal, and the calculated bandstructure of the photonic crystals in the linear, nondispersive limit. We show that wave packets from different bands can experience significantly modified effective material properties.

Journal Article↗
PubMed2001

Thoracoabdominal intestinal duplication with absent inferior vena cava.

We report a rare case of thoracoabdominal intestinal duplication with absent inferior vena cava (IVC). The patient was initially explored with a mistaken diagnosis of diaphragmatic hernia on the basis of a chest radiograph and barium meal. However, a subsequent computed tomography scan revealed a mediastinal mass with an air-fluid level, a hugely dilated azygos vein, and an absent IVC. Thoracoabdominal exploration was required to excise the duplication cyst arising from the jejunum. We believe that this is the first report of this association.

Azygos Vein↗
PubMed2000

Retrospective analysis of surgical outcome, symptom changes, and hearing improvement following myringoplasty.

This study examines the surgical and audiologic results of myringoplasty and what factors affect these outcomes. It also examines whether patients experience any improvement in their main symptoms following surgery. This was a retrospective analysis of case notes, patient questionnaires, and audiograms of all patients undergoing myringoplasty between 1990 and 1995 at Walsgrave Hospital, Coventry, UK. Overall success of myringoplasty for consultants was 81% and for trainees was 79%, with an overall success rate of 86% in children. Posterior and inferior perforations had a 90% success rate for repair, compared to only 67% of anterior perforations. There was a statistically significant reduction in air-bone gaps following myringoplasty, and the majority of patients felt that their ears were drier and had improved hearing. Myringoplasty is a successful procedure in the hands of consultants and trainees alike. The results are satisfactory enough to justify surgery purely for deafness and also in symptomatic children. There is a strong correlation between surgical success and resolution of symptoms and generally a satisfactory improvement in hearing.

Adolescent↗
PubMed1998

Kikuchi's disease of the neck (histiocytic necrotizing lymphadenitis).

Histocytic necrotizing lymphadenitis (HNL), also known as Kikuchi's disease is a benign self limiting disease of unknown origin. It effects cervical lymph nodes, predominantly in young females. It is well described in the pathology literature, but little is written about this in the ENT literature, as few clinicians are probably aware of this condition. Five cases of cervical Kikuchi's disease are presented with a brief review of the literature.

Adult↗
PubMed1996

Tuberculous parotitis: a case report.

Tuberculosis of the parotid gland is rare. It cannot be distinguished d form a parotid tumour by clinical examination alone, so surgical exploration has usually been required for diagnosis. We present a case with the same diagnostic dilemma.

Biopsy, Needle↗
PubMed1996

An unusual foreign body in the larynx: a case report.

Inhalation of a foreign body is a serious event. A small proportion of foreign bodies become impacted in the larynx, when urgent recognition is required to prevent disaster. The case of an 18-month-old baby with an impacted artificial finger nail in the larynx is described along with a brief review of the literature.

Foreign Bodies↗
PubMedDate not supplied

Duplications of the alimentary tract in children.

This study was conducted to assess the clinical, diagnostic and therapeutic approach in patients with alimentary tract duplication and review the relevant literature. A retrospective analysis of 28 patients of alimentary tract duplications treated between January 1990-December 1999 was carried out. There was a male preponderance (25:3); 71% of the patients were under 2 years of age. The presenting features were related to the anatomic location. Three patients were diagnosed antenatally. Real time ultrasonography and CT scan was undertaken for preoperative evaluation in the majority of patients. In selected cases a 99m-Tc-pertechnetate scan and barium meal follow through examination were also performed. Majority of duplications were in the jejunum and ileum. Twenty percent of our patients had thoracoabdominal duplication as compared to 2% reported in literature. Four patients required to be operated upon in the emergency for related complications. In the remaining patients complete excision of the cyst was done in 21 and only mucosectomy in 3 patients. Because these lesions are rare and can present with a wide range of clinical manifestations or may even be encountered intraoperatively, the appropriate surgical management requires the surgeon to be familiar with the anatomy and clinical characteristics of these lesions.

Child, Preschool↗
PubMedDate not supplied

Sacrococcygeal teratoma with anorectal malformation.

A 7-month-old child presented with imperforate anus, penoscrotal hypospadias and transposition, and a midline mucosa-lined perineal mass. At surgery the mass was found to be supplied by the median sacral artery. It was excised and the anorectal malformation was repaired by posterior sagittal anorectoplasty. Histologically the mass revealed well-differentiated colonic tissue. The final diagnosis was well-differentiated sacrococcygeal teratoma in association with anorectal malformation.

Abnormalities, Multiple↗
PubMedDate not supplied

Manometric evaluation of postoperative patients with anorectal anomalies.

AIM: To evaluate the outcome of surgical treatment in patients with anorectal malformations and to correlate the clinical, manometric and electromyographic studies in assessment of postoperative continence in these patients. METHODS: Forty-one patients operated on for anorectal malformations were evaluated retrospectively. These included 13 patients with low anomalies, 24 with high anomalies, and 4 with congenital pouch colon. Functional results after surgical correction were assessed on clinical basis using the Kelley's scoring system and by anorectal manometry. In addition, the electrical activity of contraction of the external sphincter muscle was studied using electromyography. RESULTS: There was direct correlation between anal canal pressures and Kelley's score in patients with both high and low anomalies; Kelley's score of 6, 5, 4, 3 and less had pressures ranging between 60-75, 45-59, 30-44, 15-29 and less than 15 cm H2O, respectively. However, the electromyographic activity did not correlate well with Kelley's score. CONCLUSIONS: Anorectal manometry correlates well with Kelley's scoring system and may be a more objective method of analyzing the results of surgery. Poor correlation between Kelley's score and electromyography may be a reflection of poor compliance with instructions to voluntarily contract the muscles of continence.

Adolescent↗