Controlling and probing molecular motion with optical lattices

This thesis describes the further improvement of an already developed by our group laser system capable of delivering high energy, frequency agile, flat-top pulses and its uses in non-resonant molecular scattering diagnostics in the form of coherent Rayleigh-Brillouin scattering, as well as for optical Stark deceleration of neutral H2 molecules. This laser system is capable of delivering two computer controlled flat-top pulses of variable duration (20~1000 ns) with energies up to 700 mJ per pulse and with linearly chirped frequencies up to 1.5 GHz. With the use of constant velocity lattices driven by this system we were able to accurately obtain coherent Brillouin scattering spectra of purified air in the hydrodynamic regime where, for the first time, we observed additional spectral peaks to the main Brillouin peak, as well as up to 40% reduction of the peak due to the interaction of the laser driven electrostrictive grating with the acoustic which was launched in the gas due to its thermalisation by the optical field. Furthermore, by utilising chirped frequency optical lattices, we were able to obtain accurate coherent Rayleigh-Brillouin spectra with signal-to-noise ratios in excess of 100, in a single laser shot ( 140ns) thus reducing the acquisition times needed for such spectra by ten orders of magnitude, rendering the technique ideal for combustion and transient flow diagnostics. Finally, we report on the use of this laser system as a tool for optical Stark deceleration of neutral H2 molecules, where through a Raman tagging scheme of the interacting molecules we are proposing an efficient way to monitor the interactions occurring within the decelerating optical lattice. We hope that this technique will pave the way for the production of narrow velocity spread molecular ensembles to be used in cold collisional studies as well as sympathetic cooling

Factors associated with low bone mass in the hemodialysis patients – a cross-sectional correlation study

<p>Abstract</p> <p>Background</p> <p>Low bone mass is common in end-stage renal disease patients, especially those undergoing hemodialysis. It can lead to serious bone health problems such as fragility fractures. The purpose of this study is to investigate the risk factors of low bone mass in the hemodialysis patients.</p> <p>Methods</p> <p>Sixty-three subjects on hemodialysis for at least 6 months were recruited from a single center for this cross-sectional study. We collected data by questionnaire survey and medical records review. All subjects underwent a bone mineral density (BMD) assay with dual-energy x-ray absorptiometry at the lumbar spine and right hip. Data were statistically analyzed by means of descriptive analysis, independent t test and one way analysis of variance for continuous variables, Pearson product-moment correlation to explore the correlated factors of BMD, and stepwise multiple linear regression to identify the predictors of low bone mass.</p> <p>Results</p> <p>Using WHO criteria as a cutoff point, fifty-one subjects (81%) had a T-score lower than -1, of them 8 subjects (13%) had osteoporosis with the femoral neck most commonly affected. Regarding risk factors, age, serum alkaline phosphatase (ALP) level, and intact parathyroid hormone (iPTH) level had significant negative correlations with the femoral neck and lumbar spine BMD. On the other hand, serum albumin level, effective exercise time, and body weight (BW) had significant positive correlations with the femoral neck and lumbar spine BMD. Age, effective exercise time, and serum albumin level significantly predicted the femoral neck BMD (R²× 0.25), whereas BW and the ALP level significantly predicted the lumbar spine BMD (R²× 0.20).</p> <p>Conclusion</p> <p>This study showed that advanced age, low BW, low serum albumin level, and high ALP and iPTH levels were associated with a low bone mass in the hemodialysis patients. We suggest that regular monitoring of the femoral neck BMD, maintaining an adequate serum albumin level and BW, and undertaking an exercise program are important to improve bone health in the patients undergoing hemodialysis.</p

QTL Analysis of Shading Sensitive Related Traits in Maize under Two Shading Treatments

During maize development and reproduction, shading stress is an important abiotic factor influencing grain yield. To elucidate the genetic basis of shading stress in maize, an F2:3 population derived from two inbred lines, Zhong72 and 502, was used to evaluate the performance of six traits under shading treatment and full-light treatment at two locations. The results showed that shading treatment significantly decreased plant height and ear height, reduced stem diameter, delayed day-to-tassel (DTT) and day-to-silk (DTS), and increased anthesis-silking interval (ASI). Forty-three different QTLs were identified for the six measured traits under shading and full light treatment at two locations, including seven QTL for plant height, nine QTL for ear height, six QTL for stem diameter, seven QTL for day-to-tassel, six QTL for day-to-silk, and eight QTL for ASI. Interestingly, three QTLs, qPH4, qEH4a, and qDTT1b were detected under full sunlight and shading treatment at two locations simultaneously, these QTL could be used for selecting elite hybrids with high tolerance to shading and high plant density. And the two QTL, qPH10 and qDTS1a, were only detected under shading treatment at two locations, should be quit for selecting insensitive inbred line in maize breeding procedure by using MAS method

Interconnections coupling through substrate for frequencies up to 100 GHz

This work presents a study on the substrate noise coupling between two interconnects. A highly, a lightly and a uniformly doped substrate, approximating most modern technologies, are described. The three different doping profiles are simulated for various interconnect distances and different metal layers assuming a 65 nm bulk CMOS technology. A proper data analysis methodology is presented, including z and s parameters extraction and de-embedding procedure