ABSTRACT
The split of surface plasmon resonance of self-assembled gold nanoparticles on Si substrate is observed from the dielectric functions of the nanoparticles. The split plasmon resonances are modeled with two Lorentz oscillators: one oscillator at ~1 eV models the polarization parallel to the substrate while the other at ~2 eV represents the polarization perpendicular to the substrate. Both parallel and perpendicular resonances are red-shifted when the nanoparticle size increases. The red shifts in both resonances are explained by the image charge effect of the Si substrate.
Subject(s)
Gold/chemistry , Metal Nanoparticles/chemistry , Optics and Photonics , Oscillometry/methods , Silicon/chemistry , Surface Plasmon Resonance/methods , Absorption , Metals/chemistry , Models, Statistical , Nanoparticles/chemistry , Particle SizeABSTRACT
AIM OF STUDY: To analyze the common technical problems encountered in ThinPrep preparations. METHOD: A prospective and retrospective study of eight hundred and fifty (n = 850) conventional cervical smears with its corresponding paired ThinPrep specimens from July 1998 to December 1998. RESULTS: 139 ThinPreps were found to be technically suboptimal. Of these, 81 showed "patchy cells lost"; 18 showed "thick preparations"; 24 demonstrated "halo effect'" where the cellular material collected at the periphery of the cell circle, and 16 had "obscuring blood and amorphous debris", rendering the preparations "satisfactory for evaluation but limited" by the presence of the above artifacts. CONCLUSION: Despite its many advantages in providing standardization of specimen preparation, superb cellular presentation, reduction in the number of unsatisfactory reports and increased lesion detection rate, ThinPrep has its own limitations in terms of technical problems, ease of operation and cost effectiveness.
Subject(s)
Vaginal Smears/methods , Culture Techniques , Female , Humans , Prospective Studies , Retrospective Studies , Sensitivity and Specificity , SingaporeABSTRACT
In a case-control study carried out in the Kuala Lumpur Maternity Hospital between 1st July 1995 and 31st January 1996 the objectives were (1) to determine the rate of breastfeeding in surviving very low birthweight (VLBW, < or = 1500 g) Malaysian infants following the introduction of the Baby Friendly Hospital Concept, and (2) to identify significant predictors associated with successful breastfeeding in these infants. During the study period, 201 (1.24 per cent) of live-born infants were VLBW infants, 192 (95.5 per cent) were Malaysians, and 141 (73.4 per cent) of them survived to go home. The breastfeeding rate among all surviving VLBW Malaysian infants at the time of discharge was 40.2 per cent (57/141). The mothers of 126 (89.4 per cent) VLBW Malaysian infants were interviewed before discharge. Logistic regression analysis showed that, after controlling for various confounders, the significant predictors associated with successful breastfeeding were: (a) Malay mothers (odds ratio: 6.0; 95 per cent CI: 1.9, 19.4), (b) mothers with educational levels of between 7 and 9 years (odds ratio: 3.6; 95 per cent CI: 1.0, 12.2), and (c) earlier age of commencement of enteral feeds in the VLBW infants (for each additional day delay in commencement of feeding, odds ratio of breastfeeding was 0.5; 95 per cent CI: 0.4, 0.8).
