89 research outputs found
Polarization Spectroscopy and Collisions in NaK
We report current work to study transfer of population and orientation in collisions of NaK molecules with argon and potassium atoms using polarization labeling (PL) and laser-induced fluorescence (LIF) spectroscopy. In the PL experiment, a circularly polarized pump laser excites a specific NaK A1Ξ£ +(v=16, J) β X1Ξ£ +(v=0, J Β± 1) transition, creating an orientation (non-uniform MJ level distribution) in both levels. The linear polarized probe laser is scanned over various 3 1Ξ (v=8, J 0 Β± 1) β A1Ξ£ +(v=16, J 0 ) transitions. The probe laser passes through a crossed linear polarizer before detection, and signal is recorded if the probe laser polarization has been modified by the vapor (which occurs when it comes into resonance with an oriented level). In addition to strong direct transitions (J 0 = J), we also observe weak collisional satellite lines (J 0 = J Β±n with n = 1, 2, 3, ...) indicating that orientation is transferred to adjacent rotational levels during a collision. An LIF experiment (with linear polarized pump and probe beams) gives information on the collisional transfer of population. From these data, cross sections for both processes can be determined. We experimentally distinguish collisions of NaK with argon atoms from collisions with alkali atoms
Collisional Transfer of Population and Orientation in NaK
We report current work to study transfer of population and orientation in collisions of NaK molecules with argon and potassium atoms using polarization labeling (PL) and laser- induced fluorescence (LIF) spectroscopy. In the PL experiment, a circularly polarized pump laser excites a specific NaK A1Ξ£ +(v 0=16, J 0 ) β X1Ξ£ +(v 00=0, J 0 Β± 1) transition, creating an orientation (non-uniform MJ0 level distribution) in both levels. The linearly polarized probe laser is scanned over various 31Ξ (v, J 0Β±1) β A1Ξ£ +(v 0=16, J 0 ) transitions. The probe laser passes through a crossed linear polarizer before detection, and signal is recorded if the probe laser polarization has been modified by the vapor (which occurs when it comes into resonance with an oriented level). Using both spectroscopic methods, analysis of weak collisional satellite lines adjacent to these directly populated lines, as a function of argon buffer gas pressure and cell temperature, allows us to discern separately the effects collisions with argon atoms and potassium atoms have on the population and orientation of the molecule. In addition, code has been written which provides a theoretical analysis of the process, through a solution of the density matrix equations of motion for the system
Global analysis of data on the spin-orbit coupled and states of Cs2
We present experimentally derived potential curves and spin-orbit interaction
functions for the strongly perturbed and
states of the cesium dimer. The results are based on data from several sources.
Laser-induced fluorescence Fourier transform spectroscopy (LIF FTS) was used
some time ago in the Laboratoire Aim\'{e} Cotton primarily to study the state. More recent work at Tsinghua University provides
information from moderate resolution spectroscopy on the lowest levels of the
states as well as additional high resolution data. From
Innsbruck University, we have precision data obtained with cold Cs
molecules. Recent data from Temple University was obtained using the
optical-optical double resonance polarization spectroscopy technique, and
finally, a group at the University of Latvia has added additional LIF FTS data.
In the Hamiltonian matrix, we have used analytic potentials (the Expanded Morse
Oscillator form) with both finite-difference (FD) coupled-channels and discrete
variable representation (DVR) calculations of the term values. Fitted diagonal
and off-diagonal spin-orbit functions are obtained and compared with {\it ab
initio} results from Temple and Moscow State universities
Near-infrared (NIR) spectroscopy. A new method for arthroscopic evaluation of low grade degenerated cartilage lesions. Results of a pilot study
<p>Abstract</p> <p>Background</p> <p>Arthroscopy is a highly sensitive method of evaluating high-grade cartilage lesions but the detection of low-grade lesions is often is unreliable. Objective measurements are required. A novel NIRS (near-infrared-spectroscopy) device for detection of low-grade cartilage defects was evaluated in a preliminary clinical study.</p> <p>Methods</p> <p>In 12 patients who had undergone arthroscopy, the cartilage lesions within the medial knee compartment were classified according to the ICRS protocol.</p> <p>With a NIR spectrometer system and an optical probe, similar in design to a hook used for routine arthroscopy, the optical properties of cartilage were measured during arthroscopy.</p> <p>Results</p> <p>The mean ratio of 2 NIR absorption bands of intact cartilage 3.8 (range 2.3 to 8.7).was significantly lower than that of cartilage with grade 1 lesions (12.8, range 4.8 to 19.6) and grade 2 lesions (13.4, range 10.4 to 15.4).</p> <p>No differences were observed between grade 1 and grade 2 lesions.</p> <p>Conclusion</p> <p>NIRS can be used to distinguish between ICRS grade 1 lesions and healthy cartilage during arthroscopic surgeries. The results of this clinical study demonstrate the potential of NIRS to objectify classical arthroscopic grading systems.</p
Sex/Gender and Socioeconomic Differences in the Predictive Ability of Self-Rated Health for Mortality
Background: Studies have reported that the predictive ability of self-rated health (SRH) for mortality varies by sex/gender and socioeconomic group. The purpose of this study is to evaluate this relationship in Japan and explore the potential reasons for differences between the groups. Methodology/Principal Findings: The analyses in the study were based on the Aichi Gerontological Evaluation Study's (AGES) 2003 Cohort Study in Chita Peninsula, Japan, which followed the four-year survival status of 14,668 community-dwelling people who were at least 65 years old at the start of the study. We first examined sex/gender and education-level differences in association with fair/poor SRH. We then estimated the sex/gender- and education-specific hazard ratios (HRs) of mortality associated with lower SRH using Cox models. Control variables, including health behaviors (smoking and drinking), symptoms of depression, and chronic co-morbid conditions, were added to sequential regression models. The results showed men and women reported a similar prevalence of lower SRH. However, lower SRH was a stronger predictor of mortality in men (HR = 2.44 [95% confidence interval (CI): 2.14β2.80]) than in women (HR = 1.88 [95% CI: 1.44β2.47]; p for sex/gender interaction = 0.018). The sex/gender difference in the predictive ability of SRH was progressively attenuated with the additional introduction of other co-morbid conditions. The predictive ability among individuals with high school education (HR = 2.39 [95% CI: 1.74β3.30]) was similar to that among individuals with less than a high school education (HR = 2.14 [95% CI: 1.83β2.50]; p for education interaction = 0.549). Conclusions: The sex/gender difference in the predictive ability of SRH for mortality among this elderly Japanese population may be explained by male/female differences in what goes into an individual's assessment of their SRH, with males apparently weighting depressive symptoms more than females
The choice of self-rated health measures matter when predicting mortality: evidence from 10 years follow-up of the Australian longitudinal study of ageing
<p>Abstract</p> <p>Background</p> <p>Self-rated health (SRH) measures with different wording and reference points are often used as equivalent health indicators in public health surveys estimating health outcomes such as healthy life expectancies and mortality for older adults. Whilst the robust relationship between SRH and mortality is well established, it is not known how comparable different SRH items are in their relationship to mortality over time. We used a dynamic evaluation model to investigate the sensitivity of time-varying SRH measures with different reference points to predict mortality in older adults over time.</p> <p>Methods</p> <p>We used seven waves of data from the Australian Longitudinal Study of Ageing (1992 to 2004; N = 1733, 52.6% males). Cox regression analysis was used to evaluate the relationship between three time-varying SRH measures (global, age-comparative and self-comparative reference point) with mortality in older adults (65+ years).</p> <p>Results</p> <p>After accounting for other mortality risk factors, poor global SRH ratings increased mortality risk by 2.83 times compared to excellent ratings. In contrast, the mortality relationship with age-comparative and self-comparative SRH was moderated by age, revealing that these comparative SRH measures did not independently predict mortality for adults over 75 years of age in adjusted models.</p> <p>Conclusions</p> <p>We found that a global measure of SRH not referenced to age or self is the best predictor of mortality, and is the most reliable measure of self-perceived health for longitudinal research and population health estimates of healthy life expectancy in older adults. Findings emphasize that the SRH measures are not equivalent measures of health status.</p
Physical function and self-rated health status as predictors of mortality: results from longitudinal analysis in the ilSIRENTE study
<p>Abstract</p> <p>Background</p> <p>Physical function measures have been shown to predict negative health-related events in older persons, including mortality. These markers of functioning may interact with the self-rated health (SRH) in the prediction of events. Aim of the present study is to compare the predictive value for mortality of measures of physical function and SRH status, and test their possible interactions.</p> <p>Methods</p> <p>Data are from 335 older persons aged β₯ 80 years (mean age 85.6 years) enrolled in the "Invecchiamento e LongevitΓ nel Sirente" (<it>ilSIRENTE</it>) study. The predictive values for mortality of 4-meter walk test, Short Physical Performance Battery (SPPB), hand grip strength, Activities of Daily Living (ADL) scale, Instrumental ADL (IADL) scale, and a SRH scale were compared using proportional hazard models. Kaplan-Meier survival curves for mortality and Receiver Operating Characteristic (ROC) curve analyses were also computed to estimate the predictive value of the independent variables of interest for mortality (alone and in combination).</p> <p>Results</p> <p>During the 24-month follow-up (mean 1.8 years), 71 (21.2%) events occurred in the study sample. All the tested variables were able to significantly predict mortality. No significant interaction was reported between physical function measures and SRH. The SPPB score was the strongest predictor of overall mortality after adjustment for potential confounders (per SD increase; HR 0.64; 95%CI 0.48β0.86). A similar predictive value was showed by the SRH (per SD increase; HR 0.76; 95%CI 0.59β0.97). The chair stand test was the SPPB subtask showing the highest prognostic value.</p> <p>Conclusion</p> <p>All the tested measures are able to predict mortality with different extents, but strongest results were obtained from the SPPB and the SRH. The chair stand test may be as useful as the complete SPPB in estimating the mortality risk.</p
Assessment of mechanical properties of isolated bovine intervertebral discs from multi-parametric magnetic resonance imaging
Social Relationships and Mortality Risk: A Meta-analytic Review
In a meta-analysis, Julianne Holt-Lunstad and colleagues find that individuals' social relationships have as much influence on mortality risk as other well-established risk factors for mortality, such as smoking
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