A normalization method of the volume and geometry of tooth for X-band in vivo EPR dosimetry.

The accuracy of in vivo EPR tooth dosimetry may be influenced by the volume and geometry variations in teeth, especially when there is considerable non-uniform sensitivity distribution in the active detection area of the cavity. To solve this problem, the present research proposed a normalization method specifically for X-band EPR in vivo tooth dosimetry. The volume and geometry of the measured tooth were reconstructed by digital image processing with images of the tooth impression slices, which were obtained by a custom-made impression module.

Study of new practical ESR dosimeter based on carbonated hydroxyapatite and its dosimetric properties.

The development of new dosimeters with good dosimetric properties is important for quality control in radiation applications. A new practical electron spin resonance (ESR) dosimeter based on carbonated hydroxyapatite that simulated the composition and structure of tooth enamel was specially synthesized. The synthesized material was investigated by transmission electron microscope, X-ray diffraction, fourier transform infrared spectroscopy and X-ray photo electron spectroscopy to confirm to the main composition of carbonated hydroxyapatite with CO32- successfully doped into the crystal lattice through optimizing the synthesis process of C/P molar ratio, pH value dynamical adjustment, annealing temperature and time.

Effect of the tooth surface water on the accuracy of dose reconstructions in the X-band in vivo EPR dosimetry.

The X-band in vivo EPR tooth dosimetry is promising as a tool for the initial triage after a large-scale radiation accident. The dielectric losses caused by water on the tooth surface (WTS) are one of the major sources of inaccuracies in this method. The effect was studied by theoretical simulation calculations and experiments with water films of various thicknesses on teeth.

The Application and Distribution of Magnetic Field Modulation in the Detection Apertures of X-band EPR Cavities for In Vivo Tooth Dosimetry.

In vivo electron paramagnetic resonance tooth dosimetry could be a practical and ideal tool for quick mass triage of victims in the rescue following a disaster event involving irradiation radiation. Magnetic field modulation is an important issue to improve the sensitivity of X-band in vivo tooth dosimetry. We designed a couple of trapezoidal modulation coil sets fixed on the magnet poles that could be used to apply sufficient magnet field modulation into the detection aperture of the resonant cavity.

Calibration ruler for CW-EPR distance measurement using diradical molecule of rigid structure.

Many experimental factors and uncontrollable factors may introduce errors in the distance measurement by continuous wave electron paramagnetic resonance. To deal with this problem, several C60 nitroxide diradical adducts with rigid structure and definite molecular dimension were used as distance calibration rulers. Based on the improvement of distance calculation program via adding simulation programs of experimental spectra and dipolar broadening function, respectively, the distance calibration method was developed under different conditions such as different solvent, solution concentration, measuring temperature, and microwave power.

New developed cylindrical TM010 mode EPR cavity for X-band in vivo tooth dosimetry.

EPR tooth in vivo dosimetry is an attractive approach for initial triage after unexpected nuclear events. An X-band cylindrical TM010 mode resonant cavity was developed for in vivo tooth dosimetry and used in EPR applications for the first time. The cavity had a trapezoidal measuring aperture at the exact position of the cavity's cylindrical wall where strong microwave magnetic field H1 concentrated and weak microwave electric field E1 distributed.

Tat peptide-mediated soluble expression of the membrane protein LSECtin-CRD in Escherichia coli.

The human liver and lymph node sinusoidal endothelial cell C-type lectin (hLSECtin), a type II integral membrane protein, containing a Ca(2+)-dependent carbohydrate recognition domain (CRD), has a well-established biological activity, yet its three-dimensional structure is unknown due to low expression yields and aggregation into inclusion bodies. Previous study has demonstrated that the HIV-1 virus-encoded Tat peptide ('YGRKKRRQRRR') can increase the yields and the solubility of heterologous proteins. However, whether the Tat peptide could promote the high-yield and soluble expression of membrane proteins in Escherichia coli is not known.

Mobility study of individual residue sites in the carbohydrate recognition domain of LSECtin using SDSL-EPR technique.

Conformational changes in proteins profoundly influence their functional profiles. With site-directed spin labeling (SDSL)-electron paramagnetic resonance (EPR) spectroscopy, we investigated the mobility features of individual residue sites in the carbohydrate recognition domain (CRD) of LSECtin, a type II integral membrane protein. The mobility of six different residue sites scatting around the Ca(2+)-1-binding site were investigated by comparing their EPR spectra rotational correlation time τ(c) in order to obtain the information of conformational changes of relevant region.

[Application of ESR imaging technique in studying of skin-penetration properties of nitroxide free radical].

A set of L-band electron spin resonance imaging (ESRI) equipment suitable for biological species was developed and an ESRI experiment model for viable skin samples was established. The mechanic process of nitroxide free radical TEMPO (2,2, 6, 6-tetramethyl-1-piperidinyloxy) penetrating through skin sample and the spin density distribution of TEMPO after it interacted with skin sample were detected by the developed ESRI method. Skin samples were extracted from mice back.

Plate form three-dimensional gradient coils for L-band ESR imaging experiment.

A set of plate form three-dimensional magnetic gradient coils was developed and used in electron spin resonance imaging (ESRI) experiment. The coils were processed with whole copper plates instead of wound with copper wires, which made its structure so compact that it was much thinner and smaller comparing to those traditionally used in ESRI. The coil set had a pie-like appearance of which the total thickness was only 14 mm and the outer diameter was 250 mm.

[The effects of electromagnetic pulse on fluidity and lipid peroxidation of mitochondrial membrane].

Objective: To study the effects of intense electromagnetic pulse(EMP) on the biological effects of mitochondrial membrane.

Method: Rat liver mitochondrial suspension was exposed to EMP at 60 kV/m level. The changes of membrane lipid fluidity and membrane protein mobility were detected by ESR and spin label technique.

[Comparing the Oxygen Free Radicals and Oxygen Consumption of Leukocytes in Leukemia Patients and Healthy Persons].

Using the electron spin resonance (ESR) and probe technique, the species of reactive oxygen free radicals and the oxygen consumption were observed in the metabolic process of oxygen of leukocytes from leukemia patients and healthy persons. Results showed that weak ESR spectrum of hydroxyl radical ((*)OH) signal was detected in the leukemia patient's leukocytes, there was no significant difference in oxygen consumption with or without PMA stimulation; superoxide anion (O(2)) in normal leukocytes was detected, and oxygen consumption increased markedly compared to the normal respiration without PMA stimulation (P < 0.001).