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Biomedical subjects

B L Tan

Publications and source records attributed to B L Tan.

10 recordsLinked to original sources
PubMed2006

Factors influencing post-operative hyperglycaemia in type 2 diabetes mellitus patients managed without intra-operative insulin.

Surgery induces a 'stress' state leading to post-operative hyperglycaemia. To investigate this effect on patients with Type 2 Diabetes Mellitus, we reviewed the records of 50 diabetic patients who underwent surgery without intraoperative insulin. Demographic features together with pre-operative and post-operative blood glucose readings were noted. 27.3% of patients with well controlled pre-operative blood glucose levels developed post-operative hyperglycaemia. In contrast, 84.6% of patients with poorly controlled levels developed the same. Poor control of blood glucose and duration of operation were the only significant predictors of post-operative hyperglycaemia.

Diabetes Mellitus, Type 2↗
PubMed2005

Localization and movement of mineral oil in plants by fluorescence and confocal microscopy.

Fluorescence and confocal laser scanning microscopy were explored to investigate the movement and localization of mineral oils in citrus. In a laboratory experiment, fluorescence microscopy observation indicated that when a 'narrow' distillation fraction of an nC23 horticultural mineral oil was applied to adaxial and opposing abaxial leaf surfaces of potted orange [Citrus x aurantium L. (Sapindales: Rutaceae)] trees, oil penetrated steadily into treated leaves and, subsequently, moved to untreated petioles of the leaves and adjacent untreated stems. In another experiment, confocal laser scanning microscopy was used to visualize the penetration into, and the subsequent cellular distribution of, an nC24 agricultural mineral oil in C. trifoliata L. seedlings. Oil droplets penetrated or diffused into plants via both stomata and the cuticle of leaves and stems, and then moved within intercellular spaces and into various cells including phloem and xylem. Oil accumulated in droplets in intercellular spaces and within cells near the cell membrane. Oil entered cells without visibly damaging membranes or causing cell death. In a field experiment with mature orange trees, droplets of an nC23 horticultural mineral oil were observed, by fluorescence microscopy, in phloem sieve elements in spring flush growth produced 4-5 months and 16-17 months after the trees were sprayed with oil. These results suggest that movement of mineral oil in plants is both apoplastic via intercellular spaces and symplastic via plasmodesmata. The putative pattern of the translocation of mineral oil in plants and its relevance to oil-induced chronic phytotoxicity are discussed.

Biological Transport↗
PubMed2003

FT-IR study of a chemically amplified resist for X-ray lithography.

Microelectronic devices for future applications demand lithographic performance that falls within the 0.10 microm region and below. Chemically amplified resists (CARs), such as the positive tone commercial UVIII resist, offer a substantial gain in sensitivity, resolution, and process efficiency in deep ultraviolet, e-beam, and X-ray lithographies. In this work, the UVIII resist is characterized for X-ray lithographic applications by studying the "deprotection" or acid generation-diffusion process of the resist under different conditions of post-exposure bake (PEB) temperature and time, and of X-ray exposure dose. The X-ray irradiation from a copper anode at a wavelength of 1.33 nm was at an intensity of 30 microW/cm2 on the resist surface. The deprotection process of the resist during PEB was accurately monitored by using Fourier transform infrared (FT-IR) spectroscopy. The infrared absorption peaks at 1151, 1369, and 2977 cm(-1) in the spectrum of the UVIII resist were found to be useful indicators for the completion of deprotection. Results of the experiments showed that the performance of UVIII could be optimized at the PEB temperature of 140 degrees C, a time of 2 min, and X-ray exposure dose of 12 mJ/cm2. The change in resist thickness after PEB was also measured. The results were confirmed by scanning electron microscopy (SEM) in which a test structure as small as 0.12 microm was obtained in a 1-microm-thick UVIII resist layer.

Acrylates↗
PubMed1999

Relating in vitro/in vivo data of two controlled-release metformin formulations.

This study was conducted to compare the bioavailability of two controlled-release metformin preparations (Diabetmin Retard and Glucophage Retard) and also to correlate the in vitro and in vivo data obtained with the two preparations. Twelve healthy volunteers participated in the study, conducted according to a completely randomized, two-way crossover design. The preparations were compared using area under the plasma concentration-time curve AUC0-infinity, time to reach peak plasma concentration Tmax, and peak plasma concentration Cmax, while correlation was determined between in vitro release and in vivo absorption. Diabetmin Retard demonstrated a slower rate of in vitro release, but a faster rate of in vivo absorption than Glucophage Retard. However, the in vivo absorption of both products was found to be slower than that of drug released in vitro. A satisfactory relationship could be established between the in vitro and in vivo results, but there was no rank order correlation. No statistically significant difference was observed between the two preparations in the parameters AUC0-infinity and Cmax. However, a slight but statistically significant difference was observed between the Tmax values, but it may not be therapeutically significant. Moreover, the 90% confidence interval for the ratio of the logarithmic transformed AUC0-infinity values, as well as the logarithmic transformed Cmax values, of Diabetmin Retard over those of Glucophage Retard was within the acceptance criteria of 0.80-1.25.

Adult↗
PubMed1993

Trivalent metal ions in the prevention of calcification in glutaraldehyde treated biological tissues. Is there a chemical correlation?

The influence of chemical factors on trivalent metal ions in the prevention of calcification of glutaraldehyde treated biological tissue has been explored. The results indicate that the chemical link lies in the hard character of the trivalent metal ions. Metal ions with the hardest character appear to have the best chance of reacting with oxygen atoms of the phosphate groups at nucleation sites of hydroxyapatite. This disrupts the nucleation and thus prevents calcification in glutaraldehyde treated biological tissue.

Animals↗