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Biomedical subjects

N C Shah

Publications and source records attributed to N C Shah.

15 recordsLinked to original sources
PubMed2004

Critical configuration analysis of four methods for measuring polymerization shrinkage strain of composites.

OBJECTIVES: To compare four methods for measuring polymerization shrinkage strain of composites and to develop a rational basis for comparing data from different methods and laboratories. METHODS: Dilatometry, modified bonded disk, strain gage, and a new linear transducer method were used to measure polymerization shrinkage strain of a model composite under similar irradiation conditions. The resin consisted of an untinted resin (50:50 BISGMA/TEGDMA, 0.7% CQ, 0.35% DMAEM, 0.05% BHT) filled with 5% fumed silica and 67 wt% untreated hybrid filler. Specimens (n = 10) were exposed for 60 s at 600 mW/cm2 and then monitored for 300 s. Specimen volumes were 8 mm3 for the strain gage method, 25 mm3 for the linear transducer and dilatometer methods and 43 mm3 for the bonded disk method. The degree of constraint applied to the specimens by each method was calculated and compared. Shrinkage strain values at 60 and 300 s were tested for significance at p = 0.05 using one-way ANOVA and Tukey's test. RESULTS: Shrinkage strain magnitudes at 60 and 300 s for the four methods were significantly different (p < 0.01) The modified bonded disk method measured the highest shrinkage value and exhibited the highest degree of specimen constraint. There was a 5 s delay after light activation before strain was detected by the strain gage. SIGNIFICANCE: Specimen constraint differed in all four methods and was linearly correlated with shrinkage strain magnitude when the degree of constraint was less than 42%.

Composite Resins↗
PubMed2002

Research capacity building in general practice. The new Australian scene.

BACKGROUND: Primary care research needs strengthening. The Commonwealth Government Department of Health and Aged Care has recently funded the university departments of general practice and rural health to build research capacity in primary care. OBJECTIVE: To explore issues surrounding building primary care research capacity, as well as looking at barriers to research capacity building and ways of overcoming them. DISCUSSION: New funding provides many opportunities for increasing research capacity in primary health care areas. Different institutions will select those methods that are best suited to their skills and the requirements of their area.

Academic Medical Centers↗
PubMed2001

The acute effects of continuous and conditional neuromodulation on the bladder in spinal cord injury.

STUDY DESIGN: Laboratory investigation using serial slow-fill cystometrograms. OBJECTIVES: To examine the acute effects of different modes of dorsal penile nerve stimulation on detrusor hyperreflexia, bladder capacity and bladder compliance in spinal cord injury (SCI). SETTING: Spinal Injuries Unit, Royal National Orthopaedic Hospital, Stanmore, Middlesex, UK. METHODS: Fourteen SCI patients were examined. Microtip transducer catheters enabled continuous measurement of anal sphincter, urethral sphincter and intravesical pressures. Control cystometrograms were followed by stimulation of the dorsal penile nerve at 15 Hz, 200 micros pulse width and amplitude equal to twice that which produced a pudendo-anal reflex. Stimulation was either continuous or in bursts of one minute triggered by a rise in detrusor pressure of 10 cm water (conditional). Further control cystometrograms were then performed to examine the residual effects of stimulation. RESULTS: Bladder capacity increased significantly during three initial control fills. Continuous stimulation (n=6) significantly increased bladder capacity by a mean of 110% (+/-Standard Deviation 85%) or 173 ml (+/-146 ml), and bladder compliance by a mean of 53% (+/-31%). Conditional stimulation in a different group of patients (n=6) significantly increased bladder capacity, by 144% (+/-127%) or 230 ml (+/-143 ml). In the conditional neuromodulation experiments, the gap between suppressed contractions fell reliably as bladder volume increased, and the time from start of stimulation to peak of intravesical pressure and 50% decline in intravesical pressure rise was 2.8 s (+/-0.9 s) and 7.6 s (+/-1.0s) respectively. The two methods of stimulation were compared in six patients; in four out of six conditional neuromodulation resulted in a higher mean bladder capacity than continuous, but the difference was not significant. CONCLUSIONS: Both conditional and continuous stimulation significantly increase bladder capacity. The conditional mode is probably at least as effective as the continuous, suggesting that it could be used in an implanted device for bladder suppression.

Adult↗
PubMed2000

Rosai-Dorman disease causing cervical myelopathy.

STUDY DESIGN: A case report of a rare disease entity and review of the literature. OBJECTIVES: To illustrate the occurrence of an unusual disease affecting the spine and spinal canal. SUMMARY OF BACKGROUND DATA: Rosai-Dorman disease is considered an idiopathic benign lymphoproliferative disease that typically occurs in the earlier decades of life. The usual manifestation is painless massive cervical lymphadenopathy, although involvement of many extra nodal sites is common. This case illustrates Rosai-Dorman disease occurring in an elderly man with myelopathy and mass lesions of the cervical, thoracic, and lumbar spinal canal without typical lymphadenopathy.- METHODS: Case report illustrating clinical presentation as well as radiographic and pathologic findings, including comparisons to cases previously reported. RESULTS: Surgical decompression with incomplete resection of the lesion was performed, providing diagnosis and treatment guidance. The patient experienced significant neurologic improvement of myelopathy. CONCLUSIONS: Recognizing clinical and laboratory features of this disease may permit earlier diagnosis and limit or avoid surgical intervention in some cases.

Aged↗
PubMed2000

Magnetic resonance imaging (MRI) of Saccharum officinarum L. (sugarcane) during its growth for sucrose content.

Magnetic Resonance Imaging (MRI) was employed to monitor changes in image intensities in stems of sugarcane which reflect on the increase in sucrose concentration. Contrast in images originates in the increase of sucrose concentration in the aqueous phase of the predominant parenchyma cells and physiological changes. In matured stems mixed MR intensity patterns were observed in transverse planes. We associate this due to the reflection of vascular bundles in ground parenchyma cells which constitute 80% sucrose storage.

Magnetic Resonance Imaging↗
PubMed1997

Use of Memokath temporary urethral stent in treatment of detrusor-sphincter dyssynergia.

In spinal-injured patients, detrusor-sphincter dyssynergia (DSD) can lead to high intravesical pressures, upper tract dilation, and recurrent infections. The standard treatment for DSD is sphincterotomy and, more recently, permanent sphincter stenting. Many spinal-injury patients would prefer a reversible treatment because of concern about fertility or because they are awaiting a "miracle cure." There is also concern over the theoretical long-term risk of squamous carcinoma after permanent stenting. In view of this, the Memokath, a thermosensitive temporary stent, has been undergoing trials at our center to determine which patients could benefit. Fourteen Memokath stents have been inserted in spinal-injured patients with DSD at our center, and they have been followed up for as long as 2 years. Stents were placed under cystoscopic guidance as a day case procedure. The stents were inserted either through the sphincter alone (short [4-cm] stents; 3 patients) or through the sphincter and bladder neck (long [5-7-cm] stents; 11 patients). There were no complications during surgery in either placement or removal of these stents. There was a significant (p < 0.001) reduction in the residual urine volume after stenting. Preoperative hydronephrosis and attacks of autonomic dysreflexia noted in some patients also resolved after stenting. Short stents that bridge the external urethral sphincter were ineffective in emptying the neuropathic bladder. Therefore, we advise that only long stents that lie across both the bladder neck and the external sphincter be used. Because of its easily reversible nature, the Memokath should be adopted for use in patients who are unsure about their preferred option of bladder management and those involved in a fertility program.

Adult↗
PubMed1982

Herbal folk medicines in Northern India.

The herbal folk medicine in North India is commonly made available through the herbalists, elderly persons, sadhus (hermits), ojhas (village physicians practising witchcraft) and the traditional street vendors whether in the alpine region near the snows or in the arid region near the deserts. The Northern part of India constitutes four main broad regions: the Montane region; the sub-Montane region; the Northern plains; and the arid region. The very important herbal folk medicines which have been in vogue from ancient times in these regions, are discussed.

Humans↗
PubMedDate not supplied

A comparative study of a few tests of dynamic lung function.

A variety of tests like FEV0-76, FEV1, PFR, MEFR is in use for assessment of ventilatory function of the lungs. Each of them has some marginal advantage over the other. It is, therefore, necessary to find out their relative merits and choose the one which can provide the maximum information in a reasonably short time. In this project, a norm of all the above tests for the people of Gujarat of age group 18-20 years has been found, the relative merit of the tests has been discussed and the velocity of air flow at 0.3 sec of expiration has been suggested as the single measurement which may conveniently replace all the other above.

Adolescent↗