Phase Diagram Characterization Using Magnetic Beads as Liquid Carriers

Magnetic beads with ~1.9 µm average diameter were used to transport microliter volumes of liquids between contiguous liquid segments with a tube for the purpose of investigating phase change of those liquid segments. The magnetic beads were externally controlled using a magnet, allowing for the beads to bridge the air valve between the adjacent liquid segments. A hydrophobic coating was applied to the inner surface of the tube to enhance the separation between two liquid segments. The applied magnetic field formed an aggregate cluster of magnetic beads, capturing a certain liquid amount within the cluster that is referred to as carry-over volume. A fluorescent dye was added to one liquid segment, followed by a series of liquid transfers, which then changed the fluorescence intensity in the neighboring liquid segment. Based on the numerical analysis of the measured fluorescence intensity change, the carry-over volume per mass of magnetic beads has been found to be ~2 to 3 µl/mg. This small amount of liquid allowed for the use of comparatively small liquid segments of a couple hundred microliters, enhancing the feasibility of the device for a lab-in-tube approach. This technique of applying small compositional variation in a liquid volume was applied to analyzing the binary phase diagram between water and the surfactant C12E5 (pentaethylene glycol monododecyl ether), leading to quicker analysis with smaller sample volumes than conventional methods.     

TLD characteristic of glass,feldspathic and lithium disilicate ceramics

Thermoluminescence (TL) emission of dental ceramics could be potentially used for retrospective dosimetry purposes as this allows a quick and reliable dose assessment in case of nuclear accident or bad use of a nuclear attack. This paper reports on the chemical and luminescence characterization of glass, feldspathic and lithium disilicate glass ceramic (LS₂). Swedish and Turkish dental ceramics supplied by Vivadent Ivoclar considering: (i) the dose response in the range 10 Gy to 6.9 kGy which displays a linear dose?response at low dose values up to 36 Gy (glass and feldspathic ceramics) and shows sublinear behavior from 12 Gy to 6 kGy (lithium disilicate glass ceramics), (ii) a reproducibility of the TL signal in which the area under the glow curve increased about 25% after 10 cycles for glass and lithium disilicate ceramics and increased about 30% after seven cycles for feldspathic ceramics, (iii) stability of the luminescence emission with the elapsed time and (iv) effect of the heating rate. Glass, lithium disilicate and feldspathic ceramics display a complex UV‐blue glow emission that can be respectively fitted to five and four groups of components assuming first‐order kinetics behavior.     

Material Flows and Energy Analysis of Glass Containers Discarded in New Jersey,USA

The use of glass cullet (crushed recycled glass containers) as aggregate in construction projects and landfills has increased rapidly even though the use of cullet as feedstock in new glass container and fiberglass production is energetically more sound. The effect of increased use of cullet as aggregate has not yet been thoroughly assessed. The objectives of this study were to model and quantify glass container flows across New Jersey and the associated life cycle energy consumption, and then compare life cycle energy consumption for two different recycling scenarios and three different end‐use/disposal scenarios. The results of a material flow analysis showed that in 2008 only about 11% of the glass containers consumed in New Jersey were used as glass container or fiberglass feedstock, while five times more were used as construction aggregate. However, a lower system energy requirement can be achieved by increased use of cullet as container feedstock compared to construction aggregate, even when the cullet is transported 1,600 miles to a glass container manufacturer. Based on the uncertainty analysis, there is about an 80% probability for the scenario with increased use as container feedstock to have a lower system energy requirement when compared with all other scenarios. To achieve increased use of cullet as glass container feedstock in New Jersey, the quality of the cullet must be improved.     

A simple method of DNA extraction from whole tissues and blood using glass powder for detection of transgenic animals by PCR

A very simple and reliable method to extract DNA directly from mouse tail, rabbit ear and blood is described. Tissue was homogenized in a solution of NaI and the DNA was extracted using glass powder. The extracted DNA was obtained in sufficient quantity and purity to allow direct detection of transgene by PCR.     

Properties of pullulan-based blend films as affected by alginate content and relative humidity

Pullulan-sodium alginate blend films were prepared and characterized as a function of water activity (a_w). At low a_w, the incorporation of alginate into pullulan film increased the tensile strength and elastic modulus, but decreased the elongation at break of the composite films; the opposite trends were observed at elevated a_w. Above 0.43 a_w, water exerted a typical plasticization effect upon the biopolymer blends. As a_w increased from 0.23 to 0.43, an anti-plasticization effect was observed as tensile strength and elastic modulus increased. The glass transition temperature of all samples decreased substantially as aw increased from 0.23 to 0.84 due to the plasticization effect of water. Within this a_w range, one transition temperature was observed for all film specimens. The stretching vibration band of O-H was investigated using attenuated total reflection Fourier transform infrared spectroscopy to identify the various species of water interacting with the polysaccharide films.     

Thermoluminescence characteristics of lithium borosilicate glass doped with Sm2O3

Lithium borosilicate glass composite (SiO₂–Li₂CO₃–H₃BO₃) doped with various concentrations of Sm₂O₃ (0–0.7 mole %) was prepared using the melt quenching method. The investigated thermoluminescence (TL) characteristics of the prepared system revealed that the highest TL response was obtained for this glass composite at 0.05 mol% Sm₂O₃. In this study, the 0.05 mol% Sm₂O₃‐doped lithium borosilicate glass composite was subjected to detailed dosimetric investigation in terms of its annealing condition, dose–response, and minimum detectable dose. The reproducibility of the response, thermal characteristics, and optical fading were also studied. The obtained results showed that the prepared glass composite had a linear dose–response over the wide gamma dose range 2Gy to 2 kGy, as well as reasonable thermal fading and excellent reproducibility. These attributes render the composite under investigation promising for utilization in radiation detection.     

Novel heterobifunctionalized polystyrene-polyethylene glycol resin for simultaneous preparation of free and immobilized peptides and biological activity detected by confocal microscopy

Summary Fast and convenient binding assays using synthetic peptides are of utmost and increasing importance, especially in the search for lead structures or in the field of diagnostics. A polymeric support suitable for solid-phase peptide synthesis was functionalized with two different anchor groups. The interior part of the aminomethylated polystyrene-1%-divinylbenzene resin beads, comprising about 98% of the total loading capacity, was modified by the acid-labile ADPV anchor whereas the 2% outer surface of the polymer was covalently coated with a PEG 10 000 derivative which renders the resin surface hydrophilic and biocompatible. The novel resin was characterized by introducing marker amino acids and by infrared spectroscopy. Employing this bifunctionalized resin for peptide synthesis, free as well as polymer-bound peptides were obtained which were tested for recognition by antibody. The resin-bound peptides proved to be suitable for ELISA and fluorescence assays, as shown by confocal laser microscopic investigations. Peptides from the interior part were obtained in high yield and purity as analyzed by HPLC, electrospray mass spectrometry and Edman degradation.     

海底玄武岩玻璃中蚀变微结构:探索海洋深地生物圈的新材料

玄武岩玻璃中的生物蚀变微结构为微生物摄取玄武岩玻璃中营养成分,通过新陈代谢产生有机酸溶解玄武岩玻璃而形成的微米级孔洞或钻穴.生物蚀变微结构在现代海洋洋壳及代表古老洋壳残片的蛇绿岩和绿岩带中广泛存在.研究玄武岩玻璃中蚀变微结构的形态特征、形成机制及其时空分布,不仅对探索地球早期生命起源和演化具有重要启示意义,也为研究海洋...     

Detecting,Visualizing and Quantitating the Generation of Reactive Oxygen Species in an Amoeba Model System

Reactive oxygen species (ROS) comprise a range of reactive and short-lived, oxygen-containing molecules, which are dynamically interconverted or eliminated either catalytically or spontaneously. Due to the short life spans of most ROS and the diversity of their sources and subcellular localizations, a complete picture can be obtained only by careful measurements using a combination of protocols. Here, we present a set of three different protocols using OxyBurst Green (OBG)-coated beads, or dihydroethidium (DHE) and Amplex UltraRed (AUR), to monitor qualitatively and quantitatively various ROS in professional phagocytes such as Dictyostelium. We optimised the beads coating procedures and used OBG-coated beads and live microscopy to dynamically visualize intraphagosomal ROS generation at the single cell level. We identified lipopolysaccharide (LPS) from E. coli as a potent stimulator for ROS generation in Dictyostelium. In addition, we developed real time, medium-throughput assays using DHE and AUR to quantitatively measure intracellular superoxide and extracellular H₂O₂ production, respectively.