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Objective To evaluate the association of urolithiasis with polymorphic microsatellite (encoding cytosine, adenine, and guanine, CAG) repeats in the exon 1 region of the androgen receptor (AR) gene and thymine/adenine (TA) repeats in the oestrogen receptor (ER The results indicate that 21-CAG repeats might be related to a lower risk of stone formation in men (P<0.05). In the ER gene, the peak allelic distribution of TA repeats was 14, showing a significant difference between male stone patients and the normal control subjects (P<0.01). There were no statistical differences between female stone patients and the control subjects in either the AR or the ER gene. Conclusion Urolithiasis among men appears to be associated with AR gene CAG repeat and ER gene TA repeat polymorphisms, whereas there was no significant association among female stone patients. These sex hormone receptors seem to be related to the higher incidence of stone formation among men.

Nitride materials such as TiN and TaN have been used in the integrated circuit industry. These materials serve as the crucial barrier layer between copper and the dielectric layer, and hence should be chemically inert. However, a displacement reaction still occurs between these nitride barriers and some metal ions such as Cu 2ϩ , Ag ϩ , and Pd 2ϩ in the presence of F Ϫ . This spontaneous reaction results in the deposition of metal, and a similar reaction takes place between the metal ions and the underlying silicon substrate. Three possible mechanisms are proposed and discussed in this study. The proposed mechanisms and the details of displacement reaction were elucidated by using Auger electron spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, nuclear magnetic resonance spectroscopy, inductively coupled plasma atomic emission spectrometer, Raman and infrared spectroscopy. TiN was found to oxidize with the formation of TiF 6 2Ϫ . Despite being regarded as a contaminant, the deposited Pd was found to be capable of serving as the platform on nitride barrier for subsequent electrodeposition of Cu.

This study examines the transverse magnetic (TM) waveguide modes, which have long been considered as the unsuitable ones for the operation of the electron cyclotron maser. The beam-wave coupling strength of the TM modes, as expected, is found to be relatively weak as compared with that of the transverse electric (TE) waveguide modes. Unlike TE modes, surprisingly, the linear behavior of the TM modes depends on the sign of the wave number kz. The negative kz has a much stronger linear efficiency than that of the positive kz. The bunching mechanism analysis further exhibits that the azimuthal bunching and axial bunching do not compete but cooperate with each other for the backward-wave operation (negative kz). The current findings are encouraging and imply that TM modes might be advantageous to the gyrotron backward-wave oscillators.

Measurement of plasma density, a key parameter that control the property of processing plasmas and hence the processing results, has been the focus of extensive studies in recent years, not only for characterization of the plasmas but also for development of tools for monitoring of the plasma based processes1.Inthis study, a miniature Plasma Absorption probe (mini-PAP)[2] of outer diameter 0.9 mm, consisting of a monopole antenna formed by a section of the center conductor of a semi-rigid coaxial cable and a glass enclosure has been developed so that the perturbation to the plasma can be minimized. Experimental measurements were carried out in an inductively coupled plasma and the results show that the resonance frequency increase linearly with the source rf power, as expected. The results are also consistent with that from measurements by a Langmuir probe. The mini-PAP was also investigated numerically by employing a full wave electromagnetic simulation using a finite element code, High Frequency Structure Simulation (HFSS, ANSOFT CORP). In the simulation analysis, a coaxial line was attached to the probe head and the "driven mode" was adopted, i.e., the wave was fed into the coaxial line and the absorption spectrum, reflection coefficient vs frequency, was then analyzed. The plasma surrounding the probe was characterized by the collisional electromagnetic plasma permittivity, determined by plasma density, wave frequency and momentum transfer collisional frequency. The simulation results show that the absorption spectrum exhibits a resonance, occurring between the plasma frequency ( p ) and the surface plasma wave resonance frequency p / (1 +  d )^0.5 [2], where  d being the dielectric constant of the dielectric (glass). The effect of plasma sheath was also studied by the numerical simulation where the sheath (floating) was modeled by an air gap ( r = 1) of thickness twice the Debye length. The resonance frequency was also found to be dependent of the probe diameter and antenna length. For example, under the same plasma conditions, the resonance frequency obtained by the mini-PAP is ~30% higher than that from a PAP of conventional size (diameter 6 mm) [2]. These results are consistent with the results obtained by experimental measurements. This indicates that one can use the result from numerical simulation as a calibration for the plasma resonance probe measurement. M. A. Lieberman and A.