An ultra-stable, high-power cw Nd:YAG laser system, developed for the ground-based gravitational wave detector Advanced LIGO (Laser Interferometer Gravitational-Wave Observatory), was comprehensively ...characterized. Laser power, frequency, beam pointing and beam quality were simultaneously stabilized using different active and passive schemes. The output beam, the performance of the stabilization, and the cross-coupling between different stabilization feedback control loops were characterized and found to fulfill most design requirements. The employed stabilization schemes and the achieved performance are of relevance to many high-precision optical experiments.
The Laser Interferometer Gravitational Wave Observatory (LIGO) consists of two widely separated 4 km laser interferometers designed to detect gravitational waves from distant astrophysical sources in ...the frequency range from 10 Hz to 10 kHz. The first observation run of the Advanced LIGO detectors started in September 2015 and ended in January 2016. A strain sensitivity of better than 10 super(-23)/radicalHz was achieved around 100 Hz. Understanding both the fundamental and the technical noise sources was critical for increasing the astrophysical strain sensitivity. The average distance at which coalescing binary black hole systems with individual masses of 30Mmiddot could be detected above a signal-to-noise ratio (SNR) of 8 was 1.3 Gpc, and the range for binary neutron star inspirals was about 75 Mpc. With respect to the initial detectors, the observable volume of the Universe increased by a factor 69 and 43, respectively. These improvements helped Advanced LIGO to detect the gravitational wave signal from the binary black hole coalescence, known as GW150914.
Loss in long-storage-time optical cavities Isogai, T; Miller, J; Kwee, P ...
Optics express,
2013-Dec-02, 2013-12-02, 20131202, Letnik:
21, Številka:
24
Journal Article
Recenzirano
Odprti dostop
Long-storage-time Fabry-Perot cavities are a core component of many precision measurement experiments. Optical loss in such cavities is a critical parameter in determining their performance; however, ...it is very difficult to determine a priori from independent characterisation of the individual cavity mirrors. Here, we summarise three techniques for directly measuring this loss in situ and apply them to a high-finesse, near-concentric, 2 m system. Through small modifications of the cavity's length, we explore optical loss as a function of beam spot size over the 1-3 mm range. In this regime we find that optical loss is relatively constant at around 5 ppm per mirror and shows greater dependence on the positions of the beam spots on the cavity optics than on their size. These results have immediate consequences for the application of squeezed light to advanced gravitational-wave interferometers.
An online survey was conducted on NTU research community to understand their experience with, and preference for each RI education mode offered in NTU. The RI education modes surveyed in the general ...ranking question are Data Management Plan (DMP) workshops, Epigeum e-Learning, Compass e-newsletter (email), and NTU policy on Research Integrity and Responsible Conduct of Research. There were 242 responses, comprising 50% research students, 32.2% research staff and 17.8% faculty members. Non-parametric statistical techniques were used to analyse preferences across different RI education modes and within sub-groups (i.e., fields, age, native language, roles in research community). More than 92% of respondents subscribed to the importance of RI education, but with different preferences for education modes. With respect to RI education in NTU, Compass e-newsletters were ranked the lowest (p < 0.05). Most felt that they were too wordy and unengaging, making it difficult to absorb information. Similarly, Epigeum e-Learning (p < 0.05) and 'policy' (p < 0.05) were found to be too lengthy in presentation. The compulsory NTU RI education modes (Epigeum e-learning and 'policy') enjoyed higher participation rates of 70-80% compared with 32-37% for the self-regulated modes (DMP workshop and e-newsletter). This suggests that regulatory mechanisms are still necessary to promote participation in RI education, and thus, core RI education content should be made compulsory in research/academic institutions. Although Epigeum is a compulsory course, some may not have participated in the programme due to technical issues or they might have forgotten to participate in the programme within the permissible timeframe. For all four RI education modes in NTU, the lack of awareness was among the top cited reasons for not participating. Most NTU researchers perceived RI education positively although they may have reservations for some approaches. Conversely, e-Learning is favored over all the other modes except for the mode of Policy. Findings from this study are useful for improving the design of RI education strategies to be more appealing to the research community by enhancing user experience in terms of user-friendliness, relevance to specialisation, providing concise information and better presentation of materials For institutions with similar modes of RI education as NTU, these results may be relevant in improving participation rates and presentation of RI education modes, such as the use of infographics and more concise information.
A solid-state laser system for the next generation of gravitational wave detectors with an output power of 220 W at the wavelength of 1064 nm is presented. Single-frequency operation of the laser was ...achieved by injection-locking of a high-power ring oscillator to an amplified non-planar ring oscillator (NPRO) following the Pound–Drever–Hall scheme. The high-power stage which features four longitudinally pumped Nd:YAG laser crystals as active media in a ring resonator configuration was designed for reliable long term operation. Using a non-confocal ring cavity to filter the output beam, a pure TEM
00
mode with 168 W output power was obtained.
Background:
An 8-mm needle length is commonly used for insulin injections; however, recent recommendations suggest shorter needles may help patients avoid intramuscular injections and reduce pain, ...while maintaining adequate glucose control. The goal of these analyses was to compare the pharmacokinetics (PK) and glucodynamics (GD) of insulin lispro after a 5-mm or an 8-mm injection depth administration in 2 populations: normal weight (study 1) or obese (study 2).
Methods:
In both open-label, randomized, 2-period crossover euglycemic clamp studies, subjects received single 0.25 U/kg insulin lispro doses on 2 occasions (at 5-mm and 8-mm injection depths); samples for PK and GD analyses were collected up to 6 hours postdose. Noncompartmental PK parameters AUC0-tlast, AUC0-∞, Cmax and GD parameters Gtot, Rmax, tRmax were log-transformed prior to analysis using a mixed effects model.
Results:
There were no apparent differences between PK profiles at the 5-mm or 8-mm injection depth in either study, demonstrated by the ratios of geometric means of AUC0-tlast, AUC0-∞, and Cmax being close to 1, with 90% confidence intervals (CI) within (0.80, 1.25). There were no apparent differences between GD profiles at either injection depth with the ratios of Gtot and Rmax near unity and 90% CIs that included 1. In both studies, the tRmax values were similar between injection depths, with a small median of pairwise differences and a 90% CI that included zero.
Conclusions:
Injection depths in the 5-8 mm range did not affect the PK or GD of insulin lispro in normal weight or obese subjects.
What is already known about this subject
• The pharmacokinetics of duloxetine have been assessed in a number of clinical studies.
• Duloxetine is eliminated through oxidative metabolism via CYP1A2 ...and, to a lesser degree, CYP2D6.
• There is strong evidence that the prevalence of CYP2D6 phenotypes and the activity of CYP1A2 enzyme activity differ between Japanese and Caucasians.
• Given the characteristics of duloxetine metabolism, there is good reason to assess pharmacokinetic differences between Japanese and Caucasians.
What this study adds
• Duloxetine pharmacokinetics in Japanese or Caucasian subjects is not meaningfully different after single or multiple doses of duloxetine.
• The magnitude of pharmacokinetic differences between groups is small relative to the pharmacokinetic variability in either group, and these small differences can be accounted for by differences in body weight.
• The result of this study suggests that different dose recommendations for Caucasian or Japanese patients are not likely to be necessary.
Aims
To compare single‐ and multiple‐dose duloxetine pharmacokinetics between healthy Japanese and Caucasians.
Methods
Twenty‐four subjects of each race were given single oral doses of duloxetine (20, 40 and 60 mg) in a randomized, double‐blind study. Another 20 subjects of each race received 20, 40 mg or placebo (2 : 2 : 1) twice‐daily for 5 days.
Results
Following single doses, the mean duloxetine Cmax and AUC were approximately 20% greater in Japanese. This difference could be explained by the 15% lower average body weight in Japanese. Similar results were observed following multiple dosing.
Conclusion
Duloxetine pharmacokinetics are not meaningfully different between Japanese and Caucasians.
What is already known about this subject
• Atomoxetine is a cytochrome P450 2D6 (CYP2D6) substrate and its pharmacokinetics has been characterized in a predominantly White population during clinical ...development.
• There are scant East Asian pharmacokinetic data available.
• The CYP2D6*10 allele is particularly prevalent in East Asian populations and may contribute to the known ethnic differences in CYP2D6 metabolic capacity.
What this study adds
• The pharmacokinetics of multiple‐dose 80 mg daily atomoxetine observed in Chinese healthy subjects appears comparable to previous data in other ethnic populations.
• Homozygous CYP2D6*10 subjects appear to have higher exposures, but are not a clearly distinct group compared with other CYP2D6 extensive metabolizers.
Aims
To characterize atomoxetine pharmacokinetics, explore the effect of the homozygous CYP2D6*10 genotype on atomoxetine pharmacokinetics and evaluate the tolerability of atomoxetine, in healthy Chinese subjects.
Methods
Twenty‐four subjects, all CYP2D6 extensive metabolizers (EM), were randomized to receive atomoxetine (40 mg qd for 3 days, then 80 mg qd for 7 days) or matching placebo (2 : 1 ratio) in a double‐blind fashion. Atomoxetine serum concentrations were measured following single (40 mg) and multiple (80 mg) doses. Adverse events, clinical safety laboratory data and vital signs were assessed during the study.
Results
Atomoxetine was rapidly absorbed with median time to maximum serum concentrations of approximately 1.5 h after single and multiple doses. Atomoxetine concentrations appeared to decrease monoexponentially with a mean apparent terminal half‐life (t1/2) of approximately 4 h. The apparent clearance, apparent volume of distribution and t1/2 following single and multiple doses were similar, suggesting linear pharmacokinetics with respect to time. Homozygous CYP2D6*10 subjects had 50% lower clearances compared with other EM subjects, resulting in twofold higher mean exposures. No clinically significant changes or abnormalities were noted in laboratory data and vital signs.
Conclusions
The pharmacokinetics of atomoxetine in healthy Chinese subjects appears comparable to other ethnic populations. Multiple dosing of 80 mg qd atomoxetine was well tolerated in this study.
The ongoing global effort to detect gravitational waves continues to push the limits of precision measurement while aiming to provide a new tool for understanding both astrophysics and fundamental ...physics. Squeezed states of light offer a proven means of increasing the sensitivity of gravitational wave detectors, potentially increasing the rate at which astrophysical sources are detected by more than 1 order of magnitude. Since radiation pressure noise plays an important role in advanced detectors, frequency-dependent squeezing will be required. In this paper we propose a practical approach to producing frequency-dependent squeezing for Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO) and similar interferometric gravitational wave detectors. This work focuses on "realistic filter cavities" in the sense that optical losses in the filter cavity and squeezed light source consistent with current technology are considered. The filter cavity solution proposed for Advanced LIGO is "practical" in that it considers the nonquantum noise and readout scheme of the interferometer and a potential implementation geometry in the Advanced LIGO vacuum envelope.
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