Multispectrum Rotational States Distribution Thermometry

We introduce Multispectrum Rotational states Distribution Thermometry (MRDT) as a new optical method for primary thermometry that relies on the global fitting of multiple molecular absorption lines of the same band at different pressures. This allows leveraging the temperature-dependence of the Doppler width and also of the distribution of line intensities across the ro-vibrational band, provided a sufficiently accurate line-strength model is available. We give a preliminary demonstration of the method with a comb-locked frequency-swept cavity-ring-down spectrometer operated on the 3$\nu$$_{1}$+$\nu$$_{3}$ band of CO$_{2}$ located around 1577 nm, which stands out among other spectroscopic samples for the availability of several line intensity models of both experimental and theoretical origin. The spectra signal-to-noise ratio represents the main limitation to a combined uncertainty to 530 ppm, but the comparative analysis between different line-strength models shows promise to reduce the error budget to 33 ppm. As compared to Doppler-broadening-thermometry, an advantage of the approach is the reduced impact of a wrong modelling of the absorption line-shapes. In a reversed approach, MRDT can be applied on a gas of known temperature to set an upper limit to the accuracy of a given line intensity model

PRIMARY THERMOMETRY FROM A CO2 OVERTONE LINE VIA COMB-ASSISTED CAVITY-RING-DOWN SPECTROSCOPY

We provide the most accurate absolute temperature measurement ever performed on an atomic or molecular sample with a Doppler-Broadening-Thermometry approach. Specifically, the absorption profile of the P$_e$(12) line of the (30012) - (00001) band of a \chem{CO_2} sample at thermodynamic equilibrium is accurately measured at 1.578 $\mu$m by a comb-assisted cavity-ring-down spectrometer that combines an extremely dense frequency axis (3000 points over 4.2 GHz) with an acquisition time as low as a few seconds. The Doppler width is extracted from a refined multi-spectrum fitting procedure accounting for the speed dependence of the relaxation rates, which were found to play a role even at the very low pressures explored, from 1 to 7 Pa. The thermodynamic gas temperature is retrieved with relative uncertainties of 8·10$^{-6}$ (type A) and 11 ·10$^{-6}$ (type B), which rank the system at the first place among optical methods. Thanks to a measurement time of only ~5 h, the technique represents a promising pathway towards the optical determination of the thermodynamic temperature with a global uncertainty at the 10$^{-6}$ level \footnote{Gotti R., Moretti L., Gatti D., Galzerano G., Castrillo A., Laporta P., Gianfrani L., and Marangoni M., Phys. Rev. A 97, 12512 (2018)}. An additional element of interest derives from the forthcoming redefinition of the unit Kelvin \footnote{J. Fischer, Phil. Trans. R. Soc. A 374, 20150038 (2016)}, in 2018, which calls for primary thermometers that are capable to operate over a large part of the temperature scale with very high accuracy

Visual acuity is reduced in alpha 7 nicotinic receptor knockout mice.

PURPOSE Nicotinic receptors (nAChRs) are part of a heterogeneous family of pentameric ligand-gated ion channels that are widely expressed in the visual system. The impact of α7 homomeric nAChRs on visual function was investigated using mutant mice lacking the α7 nicotinic receptor subunit. METHODS The spatial resolution limit was measured in α7 knockout (α7 KO) and age-matched control mice using three independent methods: an operant behavioral visual task (Prusky maze), cortical visual evoked potentials (VEPs), and the pattern electroretinogram (PERG) evoked by alternating gratings of different spatial frequencies and contrasts. RESULTS Visual acuity measured by means of the visual water maze task was significantly decreased in the α7 KO mice and, concordantly, there was a reduction of the cortical spatial resolution limit measured by VEPs. However, the PERG was normal in α7 KO mice, compared with control mice. The use of fluorescently tagged cholera toxin showed that projections from the retina segregate normally in α7 KO mice and, in line with this, the visual cortical responses elicited by stimulating either eye were normally balanced in both visual cortices and showed no retinotopic anomalies. CONCLUSIONS These findings indicate that the absence of the α7 nicotinic subunit reduces visual acuity. Because the cortical output has an abnormal spatial resolution but retinal output is preserved, it can be concluded that the low visual acuity was due to a deficit specifically present in the visual cortex

Conjugating precision and acquisition time in a Doppler broadening regime by interleaved frequency-agile rapid-scanning cavity ring-down spectroscopy

We propose a novel approach to cavity-ring-down-spectroscopy (CRDS) in which spectra acquired with a frequency-agile rapid-scanning (FARS) scheme, i.e., with a laser sideband stepped across the modes of a high-finesse cavity, are interleaved with one another by a sub-millisecond readjustment of the cavity length. This brings to time acquisitions below 20 s for few-GHz-wide spectra composed of a very high number of spectral points, typically 3200. Thanks to the signal-to-noise ratio easily in excess of 10 000, each FARS-CRDS spectrum is shown to be sufficient to determine the line-centre frequency of a Doppler broadened line with a precision of 2 parts over 1011, thus very close to that of sub-Doppler regimes and in a few-seconds time scale. The referencing of the probe laser to a frequency comb provides absolute accuracy and long-term reproducibility to the spectrometer and makes it a powerful tool for precision spectroscopy and line-shape analysis. The experimental approach is discussed in detail together with experimental precision and accuracy tests on the (30 012) â\u86\u90 (00 001) P12e line of CO2at â\u88¼1.57 μm

Cavity-ring-down Doppler-broadening primary thermometry

A step forward in Doppler-broadening thermometry is demonstrated using a comb-assisted cavity-ring-down spectroscopic approach applied to an isolated near-infrared line of carbon dioxide at thermodynamic equilibrium. Specifically, the line-shape of the Pe(12) line of the (30012)â\u86\u90(00001) band of CO2 at 1.578 μm is accurately measured and its Doppler width extracted from a refined multispectrum fitting procedure accounting for the speed dependence of the relaxation rates, which were found to play a role even at the very low pressures explored, from 1 to 7 Pa. The thermodynamic gas temperature is retrieved with relative uncertainties of 8Ã\u9710-6 (type A) and 11Ã\u9710-6 (type B), which ranks the system at the first place among optical methods. Thanks to a measurement time of only â\u89\u885h, the technique represents a promising pathway toward the optical determination of the thermodynamic temperature with a global uncertainty at the 10-6 level

Sac enlargement due to seroma after endovascular abdominal aortic aneurysm repair with the Endologix PowerLink device

A patient who had undergone endovascular repair of an abdominal aortic aneurysm with the Endologix PowerLink bifurcated system presented with delayed aortic aneurysm enlargement due to assumed endotension. He was treated with aortic sac evacuation and wrapping of the endograft. This is the first report of endotension and aneurysm sac enlargement after implantation of the PowerLink endograft

High-resolution molecular fingerprinting in the 11.6-15 µm range by a quasi-CW difference-frequency-generation laser source

: We report an approach for high-resolution spectroscopy using a widely tunable laser emitting in the molecular fingerprint region. The laser is based on difference-frequency generation (DFG) in a nonlinear orientation-patterned GaAs crystal. The signal laser, a CO2 gas laser, is operated in a kHz-pulsed mode while the pump laser, an external-cavity quantum cascade laser, is finely mode-hop-free tuned. The idler radiation covers a spectral range of ∼11.6-15 µm with a laser linewidth of ∼ 2.3 MHz. We showcase the versatility and the potential for molecular fingerprinting of the developed DFG laser source by resolving the absorption features of a mixture of several species in the long-wavelength mid-infrared. Furthermore, exploiting the wide tunability and resolution of the spectrometer, we resolve the broadband absorption spectrum of ethylene (C2H4) over ∼13-14.2 µm and quantify the self-broadening coefficients of some selected spectral lines

Visual acuity is reduced in lpha 7 nicotinic receptor knockout mice

PURPOSE. Nicotinic receptors (nAChRs) are part of a heterogeneous family of pentameric ligand-gated ion channels that are widely expressed in the visual system. The impact of ␣7 homomeric nAChRs on visual function was investigated using mutant mice lacking the ␣7 nicotinic receptor subunit. METHODS. The spatial resolution limit was measured in ␣7 knockout (␣7 KO) and age-matched control mice using three independent methods: an operant behavioral visual task (Prusky maze), cortical visual evoked potentials (VEPs), and the pattern electroretinogram (PERG) evoked by alternating gratings of different spatial frequencies and contrasts. RESULTS. Visual acuity measured by means of the visual water maze task was significantly decreased in the ␣7 KO mice and, concordantly, there was a reduction of the cortical spatial resolution limit measured by VEPs. However, the PERG was normal in ␣7 KO mice, compared with control mice. The use of fluorescently tagged cholera toxin showed that projections from the retina segregate normally in ␣7 KO mice and, in line with this, the visual cortical responses elicited by stimulating either eye were normally balanced in both visual cortices and showed no retinotopic anomalies. CONCLUSIONS. These findings indicate that the absence of the ␣7 nicotinic subunit reduces visual acuity. Because the cortical output has an abnormal spatial resolution but retinal output is preserved, it can be concluded that the low visual acuity was due to a deficit specifically present in the visual cortex. (Invest Ophthalmol Vis Sci. 2012;53:1211-1218) DOI:10.1167/iovs.11-8007 N icotinic receptors (nAChRs) represent a heterogeneous family of ion channels that are differently expressed in the nervous system. There are 12 subunit genes that derive from a common ancestral gene: 9 ␣ subunits (␣2 to ␣10) and 4 ␤ subunits (␤2 to ␤4). Neuronal nAChRs fall into two main classes: homomeric or heteromeric ␣-bungarotoxin (␣Bgtx)-sensitive receptors consisting of ␣7, ␣8, or ␣7-␣8 and/or ␣10 subunits and ␣Bgtx-insensitive heteromeric receptors consisting of ␣2-␣6 and ␤2-␤4 subunits. Nicotinic AChRs are permeable to Na ϩ , K ϩ , and Ca 2ϩ ions, and their cation permeability is influenced by their subunit composition. The ␣7 subunit that forms native pentameric homomeric receptors is highly expressed in the hippocampus, hypothalamus, and neocortex of rodents. 1 Alpha-7 knockout (KO) mice, which are characterized by the loss of ␣Bgtx receptors and the lack of nicotineevoked fast desensitizing currents in neurons, 2 are viable with apparently normal brain anatomy. In terms of behavior, the performance of ␣7 KO mice in the classic Morris water maze test, the Pavlovian conditioned fear test and the prepulse inhibition paradigm are similar to those of wild-type (WT) mice, which suggests that the absence of ␣7 nAChRs has little impact on normal, baseline behavioral responses. 3 Moreover, ␣7 KO mice show a reduced anxietyrelated response, 3 whereas only mice lacking both the ␣7 and the ␤2 nAChR subunits show impaired learning and memory in a passive avoidance test, and enhanced motor activity on the rota rod. 6 Although ␣7 KO mice are widely used in behavioral studies, no attempt has been made to characterize their visual function. The ␣7 subunit is widely expressed in the visual system, particularly in the retina and retinal input recipient regions such as the dorsolateral geniculate nucleus (dLGN), the superior colliculus, and the visual cortex

Magnolia officinalis L. bark extract and respiratory diseases: From traditional Chinese medicine to western medicine via network target

The understanding of the use of Magnolia officinalis L. (Magnoliaceae) as a possible dietary supplement for supporting the treatment of airway pathologies might be of clinical interest. Two commercially available bark extracts (M. officinalis extract [MOE]) were characterized by quantitation in honokiol and magnolol content by means of high-performance liquid chromatography with UV detection. MOE effects, as well as those of the reference compounds per se, on some targets connected to airway pathologies (antibacterial- and lung and trachea relaxing- activities) were investigated. Results showed that MOE possessed interesting antibacterial activity against Staphylococcus aureus, Pseudomonas aeruginosa, and Streptococcus pneumoniae. This was accompanied by a spasmolytic and antispasmodic activity, possibly owing to its ability to concurrently modulate different targets such as H-1-, beta(2)- and muscarinic receptors and l-type calcium channels involved in bronchodilation. All these effects were directly related to the MOE content in honokiol and magnolol. In conclusion, the properties of MOE highlighted here strongly encourage its application as dietary supplement in the treatment of airway diseases

Validation of techniques to mitigate copper surface contamination in CUORE

In this article we describe the background challenges for the CUORE experiment posed by surface contamination of inert detector materials such as copper, and present three techniques explored to mitigate these backgrounds. Using data from a dedicated test apparatus constructed to validate and compare these techniques we demonstrate that copper surface contamination levels better than 10E-07 - 10E-08 Bq/cm2 are achieved for 238U and 232Th. If these levels are reproduced in the final CUORE apparatus the projected 90% C.L. upper limit on the number of background counts in the region of interest is 0.02-0.03 counts/keV/kg/y depending on the adopted mitigation technique.Comment: 10 pages, 6 figures, 6 table