Changes In Light Scattering Intensity Research Articles

Selective detection of microcracks under the surface of glass substrates by non-contact stress-induced light-scattering method with temperature variations

Demand for flexible electronics is increasing due to recent global movements related to IoT. In particular, the ultra-thin glass substrate can be bent, its use is expanding for various applications such as thin liquid crystal panels. On the other hand, fine-polishing techniques such as chemical mechanical polishing treatments, are important techniques in glass substrate manufacturing. However, these techniques may cause microcracks under the surface of glass substrates because they use mechanical friction. We propose a novel non-contact thermal stress-induced light-scattering method (N-SILSM) using a heating device for inspecting surfaces to detect polishing-induced microcracks. In this report, we carry out the selective detection of microcracks and tiny particles using an N-SILSM with temperature variation. Our results show that microcracks and tiny particles can be distinguished and measured by an N-SILSM utilizing temperature change, and that microcrack size can be estimated based on the change in light-scattering intensity.

Time-Resolved and Label-Free Evanescent Light-Scattering Microscopy for Mass Quantification of Protein Binding to Single Lipid Vesicles.

In-depth understanding of the intricate interactions between biomolecules and nanoparticles is hampered by a lack of analytical methods providing quantitative information about binding kinetics. Herein, we demonstrate how label-free evanescent light-scattering microscopy can be used to temporally resolve specific protein binding to individual surface-bound (∼100 nm) lipid vesicles. A theoretical model is proposed that translates protein-induced changes in light-scattering intensity into bound mass. Since the analysis is centered on individual lipid vesicles, the signal from nonspecific protein binding to the surrounding surface is completely avoided, offering a key advantage over conventional surface-based techniques. Further, by averaging the intensities from less than 2000 lipid vesicles, the sensitivity is shown to increase by orders of magnitude. Taken together, these features provide a new avenue in studies of protein-nanoparticle interaction, in general, and specifically in the context of nanoparticles in medical diagnostics and drug delivery.

Changes in Light Scattering Intensity of Fish Holo-, Apo- and Reconstituted Myoglobins under Thermal Denaturation

Changes in Light Scattering Intensity of Fish Holo-, Apo- and Reconstituted Myoglobins under Thermal Denaturation

Induction of Strand Breaks in Single-Stranded Polyribonucleotides and DNA by Photoionization: One Electron Oxidized Nucleobase Radicals as Precursors

As a model for the direct effect of ionizing radiation, time-resolved changes of light-scattering intensity (LSI) of aqueous, oxic solutions of single-stranded DNA samples (calf thymus, Micrococcus lysodeikticus, Clostridium perfingens), polyC, polyU, and polyA at pH 7.5−8 have been studied following pulse irradiation with 193-nm laser light. A comparison of LSI changes (an index of single-strand break formation) with transient optical absorption changes (an index of nucleic acid base radical chemistry) following pulsed 193-nm irradiation shows that strand breakage occurs at rates similar to those for the decay of the nucleic acid base radical species for DNA, polyC, and polyU but not for polyA. With the exception of polyA, 193-nm light leads to a reduction in the LSI over ∼0.2 s, indicating that strand breakage occurs by a nucleobase radical-mediated process, whereby the nucleobase radical site is transferred to the sugar moiety. With polyU and polyC, significant changes in LSI also occur on a much faste...

Interaction of Two Heads of Myosin with F-Actin: Binding of H-Meromyosin with F-Actin in the Absence of Nucleotide1

The bindings of S-1 and the two heads of HMM with pyrene-labeled F-actin were studied using the change in light-scattering intensity or that in the fluorescence intensity of the pyrenyl group. At low ionic strength (50 mM KCl), both S-1 and HMM became bound tightly with F-actin (Kd less than 0.1 microM) and both heads of HMM became bound to F-actin. The affinities of S-1 and HMM for F-actin decreased with increasing KCl concentration. In 1 M KCl, the Kd values of S-1 and HMM for F-actin were 11 and 0.58 microM, respectively. Thus, HMM was bound to F-actin 19 times more tightly than S-1. We compared the extent of binding of HMM to F-actin measured by a centrifugation method with that measured by the fluorescence change of pyrenyl-group, and found that even in 1 M KCl, HMM became bound to F-actin with a two-headed attachment. We measured the kinetics of binding and dissociation of acto-S-1 and acto-HMM from the time course of the change in light-scattering intensity after mixing S-1 or HMM with F-actin at 1 M KCl and that after mixing 1 M KCl with acto-S-1 or acto-HMM formed at low ionic strength.(ABSTRACT TRUNCATED AT 250 WORDS)

Determination of reflection coefficients for various ions and neutral molecules in sarcoplasmic reticulum vesicles through osmotic volume change studied by stopped flow technique.

Osmotic volume change of sarcoplasmic reticulum vesicles was studied by following the change in light-scattering intensity using a stopped flow apparatus. From the analysis of the initial rate of scattering change, reflection coefficients for various ions and neutral molecules were determined. The following are typical results: K+, 0.72; Tris+, 0.98; choline 1; NO3-, 0.32; Cl-, 0.46; methanesulfonate, 0.62; gluconate, 0.96; glycerol, 0.86; and glucose, 1. When the K+ permeability was increased in the presence of 10(-6) g valinomycin/ml, the reflection coefficient for K+ changed from 0.72 to 0.31. It was found that there was a close relationship between the reflection coefficients and the permeabilities of the solutes. Hydraulic conductivity was also determined from the initial rate of light scattering change and was not different for the different solutes. The water permeability was estimated to be 2.1 x 10(-3) cm/sec at 23 degrees C.

A new technique for the investigation of the low-density lipoproteins in health and disease

There is need for a simpler method of estimating triglyceride-rich lipoprotein concentrations than those at present available. We here describe a new technique in which the concentration of very low density lipoproteins ( S f 20−10 5 is estimated by measurement, in a new micronephelometer, of the intensity of red light scattered from undiluted or diluted serum samples. Lipoprotein separation is carried out by ultra-filtration of diluted serum through cellulose ester membrane fiters, and the relative concentration of the particles of different sizes is estimated by measurement of the changes in light-scattering intensity after each filtration. The measurement of light-scattering intensity (L.S.I.) is found to be highly correlated with the serum triglyceride level in samples from fasting subjects. The influence of age, sex, relative body weight, diet, caloric balance and ischaemic heart dissease on L.S.I, of filtered and unfiltered serum samples from fasting and non-fasting subjects has been studied. These results are discussed and are shown to correlate well with those obtained by more elaborate and complex methods of lipoprotein analysis.