Some notes on Dr. Yang Guo-Fan, M.D., and the forearm free flap.
Explore the source record for details and available documents.
China↗
Biomedical subjects
B C Khoo
Publications and source records attributed to B C Khoo.
A biomechanical model to determine lumbosacral loads during single stance phase in normal gait.
A dynamic biomechanical model to determine loads (joint forces) attained at the lumbosacral joint-centre during the stance phase of normal level walking was developed. The biomechanical model was based on rigid free body-segments; namely, the foot, shank, thigh, pelvis and head, arms and trunk (HAT) segments. In this biomechanical model, the forces and moments acting on the lumbar spine are derived from body-segment mass and movements of the trunk. These external forces and their moments must be equilibrated by internal forces, that is, contributions from the erector spinae or rectus abdominus muscle group, and abdominal pressures from within the trunk together with spine forces. Three-dimensional co-ordinate and ground-reaction force data were captured from five healthy young male subjects performing normal level walking in the motion analysis laboratory of the Department of Orthopaedic Surgery, National University of Singapore. These data were captured using the VICON motion analysis system. Both of these data sets were pre-processed, and together with relevant anthropometric parameters and physical measurements of the subject, were passed into the biomechanical model to compute the resultant loads at the lumbosacral joint-centre. The results of this study showed that the peak resultant loads at the lumbosacral joint-centre were between 1.45 and 2.07 times body-weight.
Adult↗
Differential regulation of RNA polymerases I, II, and III by the TBP-binding repressor Dr1.
RNA polymerases I, II, and III each use the TATA-binding protein (TBP). Regulators that target this shared factor may therefore provide a means to coordinate the activities of the three nuclear RNA polymerases. The repressor Dr1 binds to TBP and blocks the interaction of TBP with polymerase II- and polymerase III-specific factors. This enables Dr1 to coordinately regulate transcription by RNA polymerases II and III. Under the same conditions, Dr1 does not inhibit polymerase I transcription. By selectively repressing polymerases II and III, Dr1 may shift the physiological balance of transcriptional output in favor of polymerase I.
Base Sequence↗
A comparison of lumbosacral loads during static and dynamic activities.
A biomechanical model to determine the loads at the lumbosacral joint was developed. This model was used to determine the lumbosacral loads during two specific activities--a stable standing posture representing a static activity, and a normal level walk representing a dynamic activity. This study involved ten healthy and young male subjects. The results obtained indicated that the lumbosacral loads during a stable standing posture was in the range of 0.82 to 1.18 times body-weight, with a mean of 1.03 (+/- 0.11) times body-weight. In comparison, during a normal level walk the lumbosacral loads were in the range between 1.41 and 2.07 times body-weight, with a mean of 1.61 (+/- 0.24) times body-weight. The walking speed of these subjects varied between 0.96 and 1.48 ms-1, with a mean of 1.25 (+ 0.18) ms-1. Results in this study indicated that there was a significant difference (p < 0.005) between the means of the lumbosacral loads of these two specified activities. An increase of 56.3% between means of the static to the dynamic case was observed.
Abdomen↗
Gait analysis study on patients with varus osteoarthrosis of the knee.
Biomechanical changes that occur after high tibial osteotomy (HTO) was investigated in 30 patients with osteoarthrosis (OA) of the knee and 11 age-matched normal subjects. Of the 37 knees with varus OA evaluated, 21 were analyzed before and after surgery (average follow-up evaluation, two years). The mean age of the patient group was 58.2 years. Clinical assessment was based on the Hospital for Special Surgery (HSS) knee scoring system. Full-length weight-bearing radiograms were taken for the measurement of the mechanical axis of the lower limb. Results from clinical assessment showed that 90% of the patients had good or excellent postoperative clinical results, as opposed to 9.5% before surgery. An overall improvement in the gait parameters was evident in the group evaluated after surgery, although control levels were not attained. Further analysis based on moments about the knee showed that 57% of the surgically treated knees with good or excellent clinical results had abnormal load distribution. This may lead to deterioration in the future, and further surgery may be required. The abnormal loading was also reflected in the ground-reaction force vector diagram. Therefore, the force vector diagram can be used as a quick screening method to detect abnormal joint loading.
Aged↗
Use of texture analysis to discriminate between normal livers and livers with steatosis.
We describe a technique for discriminating between livers that are normal and ones that have fatty infiltrate (livers with steatosis) based upon the application of a suitably defined texture measure to the corresponding digitized ultrasonographs. In brief, this texture measure sums, from some selected optimum spatial frequency to the upper limit set by the digitizing process, the frequency components of the normalized, radial power spectral density function. The analysis was run on six cases (two normal and four with steatosis) obtained from Dunedin Public Hospital, in New Zealand. Texture measure values for these six cases were compared with the corresponding biopsy scores. The results indicate the ability of the texture measure to discriminate between the two conditions; and furthermore, to quantitatively distinguish the severity of histological change.
Diagnosis, Differential↗
Pupillary irradiance distributions for light backscattered in the human eye.
An investigation of linear knife-edge photoscreening devices for detecting focusing errors, refractive defects and other optical artifacts in the human eye is described. Pupillary irradiance distributions calculated for a model eye are shown to agree qualitatively with distributions recorded experimentally using video frame grabbing equipment. The form of the pupillary irradiance distribution from a cyclopleged human eye supports a diffuse-like characterization for the reflection/scattering processes at the retina. The extreme sensitivity of the instruments enables real-time detection of refractive effects from tear films on the cornea and real-time tracking of floaters.
Eye Diseases↗
The proboscis lateralis--a 14-year follow-up.
A short historical review of proboscis lateralis is given and some of the important contributions highlighted. Forster was the first to mention this abnormality. I collected 34 cases from the literature (including one of my own) and have divided them clinically into four groups. The proboscis is most commonly associated with deformities of the ipsilateral half nose, the eye, and its adnexa. The various lines of management of this problem are discussed. I recommend dilating the canal of the proboscis as a useful step when it is used for reconstructing the absent heminose. A case of a left proboscis lateralis associated with an ipsilateral heminasal aplasia, a bilateral cleft of the lip and palate, a congenital cleft ala, and microphthalmia with a coloboma of the lower eyelid is documented.
Abnormalities, Multiple↗
The pixie earlobe: a method of correction.
A simple method for the correction of the pixie earlobe is documented. This technique preserves the natural free border of the earlobe.
Ear, External↗