Iron deficiency in Australian-born children of Arabic background in central Sydney

OBJECTIVES

To determine the prevalence of iron depletion and deficiency, and iron-deficiency anaemia, along with risk factors for iron depletion, in Australian-born children aged 12-36 months of Arabic-speaking background.

DESIGN

Community-based survey.

SETTING

Central Sydney Area Health Service (CSAHS), NSW, April to August, 1997.

PARTICIPANTS

All children born at five Sydney hospitals between 1 May 1994 and 30 April 1996, whose mothers gave an Arabic-speaking country of birth and resided in the area served by the CSAHS.

MAIN OUTCOME MEASURES

Full blood count (haemoglobin, mean corpuscular haemoglobin, mean corpuscular volume), plasma ferritin concentration, haemoglobin electrophoresis, potential risk factors for iron depletion.

RESULTS

Families of 641 of the 1,161 eligible children were able to be contacted, and 403 agreed to testing (response rate, 62.9% among those contacted). Overall, 6% of children had iron-deficiency anaemia, another 9% were iron deficient without anaemia, and 23% were iron depleted. Multiple logistic regression analysis showed three significant independent risk factors for iron depletion: <37 weeks' gestation (odds ratio [OR], 5.88, P=0.001); mother resident in Australia for less than the median time of 8.5 years (OR, 1.96, P=0.016); and daily intake of >600 mL cows' milk (OR, 3.89, P=<0.001).

CONCLUSION

Impaired iron status is common among children of Arabic background, and targeted screening is recommended for this group.

Osteochondromas of the hand in hereditary multiple exostosis: report of a case presenting as a blocked proximal interphalangeal joint

Blocking of motion of an interphalangeal joint in the hand by an osteochondroma has not been reported previously. Osteochondromas, which are uncommon in the hand, are encountered most frequently in patients with hereditary multiple exostosis. They can occur away from the epiphyseal plate region at the distal end of the proximal and middle phalanges. Osteochondromas that occur in these locations characteristically cause angular and rotational deformities. Early recognition and prompt surgical treatment in this child resulted in full motion with minimal angular deformity.

Output power stability of GaAlAs laser transmitters using an optical tap for feedback control

Several laser transmitters assembled for 44.736-Mb/sec lightwave field experiments exhibited large, unexpected changes in output power. This problem is now identified with laser front-to-back mirror mistracking and its effect on the back-mirror-monitoring scheme used for feedback control of the laser. To correct this problem, an optical-fiber tap was developed to monitor the actual output power for feedback control. This paper describes the output power stability of five GaAIAs laser transmitters operated using this optical tap for feedback control. Results show that tap-controlled transmitters have output-power stability within +/-2% (+/-0.1 dB) over a 1000-h test period, this being an order of magnitude improvement compared with the earlier scheme of control.

Lightwave fiber tap

This paper describes a device which samples the optical signal in an optical fiber for use in source stabilization via feedback control. This device incorporates a beam splitter formed on the fiber ends to deflect a portion of the light traveling down the fiber into a P-I-N photodetector. Advantages of this device include low insertion loss, an output that is relatively independent of the modal distribution within the fiber, and is a rugged small package.

Effects of beam displacement and front and back mistracking of junction lasers on lightwave transmitter output stability

We have performed experiments to evaluate the sensitivity of the optical output power in lightwave transmitters to possible changes in coupling between the injection laser and the optical fiber. Specifically, coupling changes attributable to beam wander and moding in the laser as well as mechanical motion between the laser and fiber were considered. Since complete transmitters use feedback control circuitry to maintain the output power constant, the effects of beam wander and moding on the feedback sensors (photodiodes, either near the laser or in an optical-fiber tap) were also measured. Based on our results, a comparison of back-mirror monitoring vs fiber-tap monitoring for feedback control is presented. The effects of front/back-mirror mistracking often observed in injection lasers were also considered when comparing these two monitoring schemes. We conclude that fiber-tap monitoring is preferable from a system point of view.

Nd:YAIG Laser Cavity Loss due to an Internal Brewster Polarizer

When an internal Brewster plate is used to polarize a Nd:YAIG laser, its output power generally decreases. This is shown to be largely due to the thermally induced birefringence in the laser rod, which causes a polarization rotation inside the optical cavity and hence a reflection loss at the polarizer. Calculation of this loss for a typical laser has been made and is compared to observed decreases in output power.