Background: Urinary iodine is a good biochemical marker for control of iodine deficiency disorders. Our aim was to develop and validate a simple, rapid, and quantitative method based on the Sandell–Kolthoff reaction, incorporating both the reaction and the digestion process into a microplate format. Methods: Using a specially designed sealing cassette to prevent loss of vapor and cross-contamination among wells, ammonium persulfate digestion was performed in a microplate in an oven at 110 °C for 60 min. After the digestion mixture was transferred to a transparent microplate and the Sandell–Kolthoff reaction was performed at 25 °C for 30 min, urinary iodine was measured by a microplate reader at 405 nm. Results: The mean recovery of iodine added to urine was 98% (range, 89–109%). The theoretical detection limit, defined as 2 SD from the zero calibrator, was 0.11 μmol/L (14 μg/L iodine). The mean intra- and interassay CVs for samples with iodine concentrations of 0.30–3.15 μmol/L were ≤10%. The new method agreed well with the conventional chloric acid digestion method (n = 70; r = 0.991; y = 0.944x + 0.04; Sy|x = 0.10) and with the inductively coupled plasma mass spectrometry method (n = 61; r = 0.979; y = 0.962x + 0.03; Sy|x = 0.20). The agreement was confirmed by difference plots. The distributions of iodine concentrations for samples from endemic areas of iodine deficiency diseases showed similar patterns among the above three methods. Conclusions: Our new method, incorporating the whole process into a microplate format, is readily applicable and allows rapid monitoring of urinary iodine.

We have developed a novel, practical micro-ELISA system for sensitive and rapid allergy diagnosis. The enzymatic reactions occurred under stopped-flow conditions, resulting in both high precision and high sensitivity. A BSA-biotin-avidin linker was introduced for the immobilization of water-soluble allergens on polystyrene microbeads, enabling immobilization of allergens in sufficient density to provide high sensitivity. Evaluation of the system's performance showed a good detection limit (2 ng/mL) for total IgE measurement. In addition, a good correlation with a conventional method (CAP method) was demonstrated using human serum samples from 85 allergy patients. Importantly, sample volumes (5 microL) were 10 times smaller and analysis time (12 min) was >20 times faster than the conventional method. All procedures were automatically regulated with our simple microfluidic system, and all the fluidic, optic and electronic components were integrated for portability. We believe that our system has the potential to become a very powerful tool, particularly for point-of-care diagnosis.

We report a systematic study of the dynamic microwave conductivity near Tc for La2−xSrxCuO4 (LSCO) thin films with x=0.07 to 0.16. The strong frequency dependence of the phase stiffness together with scaling analysis of the ac fluctuating conductivity of superconductivity provide direct evidence for the 2D-XY behavior of nearly decoupled CuO2 planes in underdoped LSCO (x=0.07 and 0.12). On the other hand, the critical exponents for slightly overdoped LSCO (x=0.16) were found to agree with those for the relaxational 3D-XY model, indicating that the universality class in LSCO is changed by hole doping. The implication of these results for the phase diagram of high-Tc cuprates is discussed.One of the hallmarks of the high-T c cuprates is the large thermal fluctuation of the superconducting order enhanced by the short coherence length and the quasi two-dimensionality, which enables the exploration of the fluctuation-dominated critical regime very close to T c 1 . Although numerous measurements, such as the ac conductivity 2 , the dc magnetization 3 , the specific heat 4 , and the I-V curves 5 , have been performed to investigate the critical fluctuation, there has been no consensus among the results. This is surprising because the critical phenomena were considered to be universal, independent of the microscopic details 6 . However, if many assumptions were made implicitly to determine the universality class of the phase transition from the data, the obtained results are not convincing unless the validity of such assumptions is confirmed. Thus, one should develop a more reliable method which does not require any extra assumptions. To our knowledge, the most successful method is dynamic scaling analysis of the ac complex conductivity, σ(ω) = σ 1 (ω) − iσ 2 (ω), as will be discussed later.Another fascinating hallmark of the high-T c cuprates is that the physical properties change with hole doping. In particular, an understanding of the phase diagram as a plot of T c versus the hole concentration has been a central issue in the physics of high-T c cuprates. Interestingly, some recent models, which start from the quantum criticality for competing orders underlying the phase diagram of high-T c cuprates, provide another possible explanation for the critical fluctuations in high-T c cuprates. That is, the critical fluctuations change with hole doping, because of the existence of a quantum critical point (QCP) 7 . These models suggest that the critical dynamics should be investigated as a function of hole doping. Thus, it can be expected that such a systematic study across the phase diagram will not only resolve the disagreements among earlier studies but will also provide important information to understand the phase diagram of high-T c cuprates.In this paper, we report a systematic study of σ(ω) as a function of the swept-frequency (0.1 GHz to 12 GHz) for high-quality La 2−x Sr x CuO 4 (LSCO) thin films with a wide range of hole concentrations (x=0.07 to 0.16). For underdoped (UD) LSCO, we show clear evidence for the 2D-X...

Iodine intake assessed by UIC in Japanese pregnant women is regarded as sufficient and not excessive according to World Health Organization criteria. Although the data are local, our results provide additional information on the reference range for UIC throughout gestation in iodine-sufficient areas.