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Biomedical subjects

H S Ranu

Publications and source records attributed to H S Ranu.

At least 19 recordsLinked to original sources
PubMed1998

Bioengineering in the millennium.

This symposium identified the major challenges in biomedical research that will benefit from bioengineering applications. Attention was focused on the important role that bioengineers will play in future advances in biomedical research. There was considerable discussion about how to integrate bioengineering with biological research in meeting the challenges of the twenty-first century. Symposium presenters showcased the accomplishments of NIH-funded bioengineering researches and increased the visibility of bioengineering to NIH leaders, staff, and members of the intramural and extramural research community. Recommendations were also made for future NIH-funded research projects. Attention was also placed on how basic bioengineering research can lead to commercialization of new health care technology and therefore maintain the nation's leadership in this important area. New products, from biotechnology and novel devices for diagnosis and treatment, are marketed through interactions between universities, medical centers, small start-up firms, and larger, more established companies. In the United States the gross revenue of the bioengineering private sector industry involved in the manufacture of health care products already exceeds $40 billion. More then 750 persons attended this bioengineering symposium. Over 110 scientific posters and exhibits relating to biology and medicine were presented. They provided a forum for showcasing NIH-funded bioengineering projects and fostered future collaboration among academic investigators, industry, and members of the small business community. The contributions of Pugwash bioengineer, Maciej Natecz, a member of the Polish Academy of Sciences, was recognized by the Conference Planning Committee. He was honored for his work in nuclear disarmament. Indian medical scientists should note that this symposium provided a framework for the development of technology in biomedical sciences during the Twenty-First Century. Major concentrations in interdisciplinary research should occur at all of the premier research institutions in India.

Animals↗
PubMed1998

Bioengineering in the Millennium, National Institute of Health Symposium, Bioengineering: Building the Future of Biology and Medicine.

This symposium identified the major challenges in biomedical research that will benefit from bioengineering applications. Attention was focused on the important role that bioengineers will play in future advances in biomedical research. There was considerable discussion about how to integrate bioengineering with biological research in meeting the challenges of the twenty-first century. Symposium presenters showcased the accomplishments of NIH-funded bioengineering researches and increased the visibility of bioengineering to NIH leaders, staff and members of the intramural and extramural research community. Recommendations were also made for future NIH-funded research projects. Attention was also placed on how basic bioengineering research can lead to commercialization of new health care technology and therefore maintain the Nation's leadership in this important area. New products, from biotechnology and novel devices for diagnosis and treatment, are marketed through interactions between universities, medical centers, small start-up firms, and larger, more established companies. In the United States the gross revenue of the bioengineering private sector industry involved in the manufacture of health care products already exceeds $40 billion. More than 750 persons attended this bioengineering symposium. Over 110 scientific posters and exhibits relating to biology and medicine were presented. They provided a forum for showcasing NIH-funded bioengineering projects and fostered future collaboration among academic investigators, industry and members of the small business community. The role of bioengineering in the 21st century has already been highlighted by the author as far as research, education and space age technologies are concerned. The contributions of Pugwash bioengineer, Maciej Natecz, a member of the Polish Academy of Sciences, was recognized by the Conference Planning Committee. He was honoured for his work in nuclear disarmament.

Biocompatible Materials↗
PubMed1993

Multipoint determination of pressure-volume curves in human intervertebral discs.

To gain further insight into the biomechanics of the human intervertebral disc and to determine a potential mechanism for causation and relief of symptoms related to a herniated disc, the pressure-volume relation was determined within the nucleus pulposus. Pressure was measured continuously within the nucleus pulposus in 17 intact lumbar discs from human cadavers by means of a miniature strain gauge at the tip of a size 4 French (1.3 mm) catheter inserted into the nucleus pulposus. The volume of the nucleus pulposus was increased at the slow, continuous rate of 0.034 ml/min by the pump regulated infusion of saline coloured with methylene blue. In 12 unloaded discs, nucleus pulposus pressure rose in a linear fashion (linear r = 0.96) from an initial mean pressure of 174 (SD 81) kPa. The mean rate of pressure rise was 327 (SD 109) kPa/ml volume increase. The peak pressure measured was 550 kPa; this was slightly higher than the capability of the transducer. Similar linear relations were obtained during infusion of saline into five vertically loaded discs fixed at the deformation produced by a 9.1 kg weight. The data define the pressure-volume relation within the disc and show that the nucleus pulposus, surrounded by the relatively inelastic annulus and the solid vertebral end plates, has the properties of a tight hydraulic space in which a large pressure rise will regularly result from a small increase in volume. Presumably the opposite is also true. The data may provide a biomechanical basis for the physiological variation in symptoms related to the disc, and for any benefits obtained from interventions designed to remove disc tissue.

Biomechanical Phenomena↗
PubMed1992

Percutaneous laser disc decompression. A new therapeutic modality.

The authors present a new advance in the treatment of herniated disc disease using percutaneous Nd:YAG laser to vaporize a small portion of nucleus pulposus, thereby decompressing the disc. In vitro and in vivo animal data are presented. Three hundred seventy-seven magnetic resonance imaging or computed tomography scan-documented, herniated, nonsequestered lumbar intervertebral discs with corresponding clinical findings in 333 patients were so treated in an outpatient setting. The longest follow-up was 62 months, with a mean of 26 months. According to the Macnab criteria, there was a good to fair response in 261 patients (78.4%), and a poor response in 72 (21.6%); 166 patients experienced relief of pain during the procedure. One-third of repeat magnetic resonance imaging scans at 4-6 months postlaser treatment showed modest to moderate decrease of disc herniation.

Adult↗
PubMed1990

Measurement of pressures in the nucleus and within the annulus of the human spinal disc: due to extreme loading.

Specially developed intervertebral and intradiscal pressure transducers are used to map the pressures in the nucleus pulposus and within the annulus fibrosus of the human spinal discs, to the point of fracture of the segmental units. The results show that for normal discs, pressures in the nucleus and in the annulus are linearly related to each other and to the applied compressive loads. Mechanical strains which develop around the periphery of the vertebral body are also linear with the applied compressive loads, when the partial vertebral column is loaded to the point of bony fracture. Failure of the intervertebral discs at the point of fracture occurred through the vertebral body endplates and the annulus fibrosus remained intact.

Adult↗
PubMed1990

A vertebral finite element model and its response to loading.

A finite element model of a complete vertebra has been developed. The response of the loads applied to the model nodes were correlated with the experimentally measured pressures on the vertebral endplate. Model results were also validated against experimental data and were found to have a reasonably good correlation with measured strains. The model confirmed that there were high stresses at the junction of the pedicles with the body, along the anterior aspects of the body and near the pars interarticularis. The model was further used to simulate partial and full laminectomies on the right side of the vertebra. This resulted in high tensile stresses in the pedicles and in the region of the pars interacticularis, especially when the upper portion of the lamina was taken out.

Biomechanical Phenomena↗
PubMed1987

Normal and pathological human gait analysis using miniature triaxial shoe-borne load cells.

Miniature triaxial shoe-borne load cells are used to analyze the normal and a below knee amputee's gait. The gait of an amputee is studied from first step on a temporary pylon to a final "normal" gait on a permanent prosthesis. The amputee's gait is compared to that of the normal subject. The load cells are an effective method of analyzing normal and abnormal gait. For an amputee, it is possible to identify misalignments from the output of the various load cells. This method may also be useful for identifying and correcting problems in the painful below knee stump. These load cells are further used to compute the center of pressure of a normal subject and a below knee amputee. Analysis of the resulting patterns has been found to be extremely useful as a measure of the subject's functional mobility.

Adult↗
PubMed1986

Miniature load cells for the measurement of foot-ground reaction forces and centre of foot pressure during gait.

A knowledge of the function of the foot is essential for an understanding of the mechanics of gait. In particular it is necessary to measure the forces, and their directions, between the foot and the ground. Miniature shoe borne load cells were used to measure the centre of foot pressure of a normal subject, a below knee amputee and a polio patient. An analysis of the resulting force patterns has been found useful as a measure of a subject's functional mobility. This paper describes a system which has been developed to measure and analyse the distribution of the forces acting on the foot of a polio patient, an amputee and group of normal subjects.

Adult↗
PubMed1986

Characterization of bone materials as ultrasonic transducers.

Physical, dielectric, piezoelectric and electromechanical parameters have been reported for bone and its two major constituents i.e. collagen and apatite, for their characterization as ultrasonic transducer materials. Collagen and apatite have been extracted from full bone using well known methods. These materials have been used to prepare simple disc-shaped test pieces (dimensions: diameter 10 mm and thickness 1.0 +/- 0.01 mm). The variation of various electrical parameters with frequency in the region (1-108 MHz) is examined for these materials. These include impedance, phase angle, relative voltage output, quality factor 'Q', dielectric constant and resistivity. The data so obtained are compared with those for ceramic and quartz transducers. The observations on impedance, phase and relative voltage output for bone materials indicate that the first resonance peak falls around 56 MHz followed by second and third harmonics around 112 MHz and 168 MHz respectively. A low 'Q' value suggests a fairly wide band transducer, while other parameters compare favourably with ceramic and quartz materials. Bone material has also been used to obtain a transducer in the standard configuration and velocity dispersion in the frequency range 1-108 MHz is examined.

Animals↗
PubMed1982

Three dimensional surgical simulations of the spine.

A finite element model of a complete vertebra has been formulated. It is used to simulate the laminectomy and Harrington rod procedures. The results indicate that high tensile stresses occurred on the affected side in the region of the pars interarticularis after laminectomy. High tensile stresses near the pars interarticularis and at the posterior junction of lamina and pedicles are predicted due to Harrington rod loading.

Humans↗
PubMed1980

A comparison of different treatment regimes on the visual appearance and mechanical properties of mouse skin.

Four different regimes of radiotherapy employed in the treatment of basal cell epitheliomas were compared in order to assess their effect on the visual appearance and mechanical properties of skin. Three groups of mice received exposures identical to those given in the radiotherapy treatments; three months after completion of the radiation the visual and mechanical properties of the skin and its appendages were examined. The skin scarring, coat condition, greying of hair, skin, thickness, load at rupture, extension at rupture, mechanical stress at rupture and stiffness were used as cirteria for comparing the four treatments. The treatment regime which caused the least damage to normal skin was identified.

Animals↗