Intensities and self-broadening coefficients of the strongest water vapour lines in the 2.7 and 6.25μm absorption bands

Intensities and self-broadening coefficients are presented for about 460 of the strongest water vapour lines in the spectral regions 1400–1840 cm−1 and 3440–3970 cm−1 at room temperature, obtained from rather unique measurements using a 5-mm-path-length cell. The retrieved spectral line parameters are compared with those in the HITRAN database ver. 2008 and 2012 and with recent ab-initio calculations. Both the retrieved intensities and half-widths are on average in reasonable agreement with those in HITRAN-2012. Maximum systematic differences do not exceed 4% for intensities (1600 cm−1 band) and 7% for self-broadening coefficients (3600 cm−1 band). For many lines however significant disagreements were detected with the HITRAN-2012 data, exceeding the average uncertainty of the retrieval. In addition, water vapour line parameters for 5300 cm−1 (1.9 μm) band reported by us in 2005 were also compared with HITRAN-2012, and show average differences of 4–5% for both intensities and half-widths

Infrared Absorption Spectra, Radiative Efficiencies, and Global Warming Potentials of Newly-Detected Halogenated Compounds: CFC-113a, CFC-112 and HCFC-133a

CFC-113a (CF3CCl3), CFC-112 (CFCl2CFCl2) and HCFC-133a (CF3CH2Cl) are three newly detected molecules in the atmosphere that are almost certainly emitted as a result of human activity. It is important to characterise the possible contribution of these gases to radiative forcing of climate change and also to provide information on the CO2-equivalence of their emissions. We report new laboratory measurements of absorption cross-sections of these three compounds at a resolution of 0.01 cm−1 for two temperatures 250 K and 295 K in the spectral range of 600–1730 cm−1. These spectra are then used to calculate the radiative efficiencies and global warming potentials (GWP). The radiative efficiencies are found to be between 0.15 and 0.3 W∙m−2∙ppbv−1. The GWP for a 100 year time horizon, relative to carbon dioxide, ranges from 340 for the relatively short-lived HCFC-133a to 3840 for the longer-lived CFC-112. At current (2012) concentrations, these gases make a trivial contribution to total radiative forcing; however, the concentrations of CFC-113a and HCFC-133a are continuing to increase. The 2012 CO2-equivalent emissions, using the GWP (100), are estimated to be about 4% of the current global CO2-equivalent emissions of HFC-134a

Recommended isolated-line profile for representing high-resolution spectroscopic transitions (IUPAC Technical Report)

The report of an IUPAC Task Group, formed in 2011 on "Intensities and line shapes in high-resolution spectra of water isotopologues from experiment and theory" (Project No. 2011-022-2-100), on line profiles of isolated high-resolution rotational-vibrational transitions perturbed by neutral gas-phase molecules is presented. The well-documented inadequacies of the Voigt profile (VP), used almost universally by databases and radiative-transfer codes, to represent pressure effects and Doppler broadening in isolated vibrational-rotational and pure rotational transitions of the water molecule have resulted in the development of a variety of alternative line-profile models. These models capture more of the physics of the influence of pressure on line shapes but, in general, at the price of greater complexity. The Task Group recommends that the partially Correlated quadratic-Speed-Dependent Hard-Collision profile should be adopted as the appropriate model for high-resolution spectroscopy. For simplicity this should be called the Hartmann--Tran profile (HTP). The HTP is sophisticated enough to capture the various collisional contributions to the isolated line shape, can be computed in a straightforward and rapid manner, and reduces to simpler profiles, including the Voigt profile, under certain simplifying assumptions.Comment: Accepted for publication in Pure and Applied Chemistr

The water vapour continuum in near-infrared windows – current understanding and prospects for its inclusion in spectroscopic databases

Spectroscopic catalogues, such as GEISA and HITRAN, do not yet include information on the water vapour continuum that pervades visible, infrared and microwave spectral regions. This is partly because, in some spectral regions, there are rather few laboratory measurements in conditions close to those in the Earth’s atmosphere; hence understanding of the characteristics of the continuum absorption is still emerging. This is particularly so in the near-infrared and visible, where there has been renewed interest and activity in recent years. In this paper we present a critical review focusing on recent laboratory measurements in two near-infrared window regions (centred on 4700 and 6300 cm−1) and include reference to the window centred on 2600 cm−1 where more measurements have been reported. The rather few available measurements, have used Fourier transform spectroscopy (FTS), cavity ring down spectroscopy, optical-feedback – cavity enhanced laser spectroscopy and, in very narrow regions, calorimetric interferometry. These systems have different advantages and disadvantages. Fourier Transform Spectroscopy can measure the continuum across both these and neighbouring windows; by contrast, the cavity laser techniques are limited to fewer wavenumbers, but have a much higher inherent sensitivity. The available results present a diverse view of the characteristics of continuum absorption, with differences in continuum strength exceeding a factor of 10 in the cores of these windows. In individual windows, the temperature dependence of the water vapour self-continuum differs significantly in the few sets of measurements that allow an analysis. The available data also indicate that the temperature dependence differs significantly between different near-infrared windows. These pioneering measurements provide an impetus for further measurements. Improvements and/or extensions in existing techniques would aid progress to a full characterisation of the continuum – as an example, we report pilot measurements of the water vapour self-continuum using a supercontinuum laser source coupled to an FTS. Such improvements, as well as additional measurements and analyses in other laboratories, would enable the inclusion of the water vapour continuum in future spectroscopic databases, and therefore allow for a more reliable forward modelling of the radiative properties of the atmosphere. It would also allow a more confident assessment of different theoretical descriptions of the underlying cause or causes of continuum absorption

Water vapour self-continuum in near-visible IR absorption bands: Measurements and semiempirical model of water dimer absorption

The nature of the water vapour continuum has been of great scientific interest for more than 60 years. Here, water vapour self-continuum absorption spectra are retrieved at temperatures of 398 K and 431 K and at vapour pressures from 1000 to 4155 mbar in the 8800 and 10,600 cm−1 absorption bands using high-resolution FTS measurements. For the observed conditions, the MT_CKD-3.2 model underestimates the observed continuum on average by 1.5–2 times. We use the hypothesis that water dimers contribute to the continuum absorption to simulate the experimentally-retrieved self-continuum absorption spectra, and to explain their characteristic temperature dependence and spectral behaviour. The values of the effective equilibrium constant are derived for the observed temperatures. We find that the dimer-based model fits well to the measured self-continuum from this and previous studies, but requires a higher effective equilibrium constant compared to the modern estimates within the temperature range (268–431 K) and spectral region studied. It is shown that water dimers are likely responsible for up to 50% of the observed continuum within these bands. Possible causes of the incomplete explanation of the continuum are discussed. Extrapolating these measurements to atmospheric temperatures using the dimer-based model, we find that the newly-derived self-continuum reduces calculated surface irradiances by 0.016 W m−2 more than the MT_CKD-3.2 self-continuum in the 8800 cm−1 band for overhead-Sun mid-latitude summer conditions, corresponding to a 12.5% enhancement of the self-continuum radiative effect. The change integrated across the 10,600 cm−1 band is about 1%, but with significan

Water vapour self-continuum in near-visible IR absorption bands: measurements and semiempirical model of water dimer absorption

The nature of the water vapour continuum has been of great scientific interest for more than 60 years. Here, water vapour self-continuum absorption spectra are retrieved at temperatures of 398 K and 431 K and at vapour pressures from 1000 to 4155 mbar in the 8800 and 10,600 cm−1 absorption bands using high-resolution FTS measurements. For the observed conditions, the MT_CKD-3.2 model underestimates the observed continuum on average by 1.5–2 times. We use the hypothesis that water dimers contribute to the continuum absorption to simulate the experimentally-retrieved self-continuum absorption spectra, and to explain their characteristic temperature dependence and spectral behaviour. The values of the effective equilibrium constant are derived for the observed temperatures. We find that the dimer-based model fits well to the measured self-continuum from this and previous studies, but requires a higher effective equilibrium constant compared to the modern estimates within the temperature range (268–431 K) and spectral region studied. It is shown that water dimers are likely responsible for up to 50% of the observed continuum within these bands. Possible causes of the incomplete explanation of the continuum are discussed. Extrapolating these measurements to atmospheric temperatures using the dimer-based model, we find that the newly-derived self-continuum reduces calculated surface irradiances by 0.016 W m−2 more than the MT_CKD-3.2 self-continuum in the 8800 cm−1 band for overhead-Sun mid-latitude summer conditions, corresponding to a 12.5% enhancement of the self-continuum radiative effect. The change integrated across the 10,600 cm−1 band is about 1%, but with significant differences spectrally

Differences in matrix metalloproteinase-1 and matrix metalloproteinase-12 transcript levels among carotid atherosclerotic plaques with different histopathological characteristics

Background and Purpose— Previous studies have shown that atherosclerotic lesions express a number of matrix metalloproteinases (MMPs). Here we investigated whether transcript levels of MMP-1, -3, -7, -9, and -12 in carotid atherosclerotic plaques were correlated with histological features and clinical manifestations.Methods— Atherosclerotic plaques (n=50) removed from patients undergoing carotid endarterectomy were classified histologically using a system proposed by Virmani et al, and MMP-1, -3, -7, -9, and -12 transcript levels in these tissues were quantified by real-time reverse-transcriptase polymerase chain reaction.Results— Compared to plaques with a thick fibrous cap, those with a thin cap had a 7.8-fold higher MMP-1 transcript level (P=0.006). MMP-3, -7, and -12 were 1.5-fold, 1.8-fold, and 2.1-fold, respectively, higher in thin cap plaques, but the differences did not reach statistical significance. MMP-12 transcript levels were significantly increased in ruptured plaques compared with lesions without cap disruption (P=0.001). MMP-9 transcript levels were similar among the different types of lesion. MMP-1 and -12 transcript levels were significantly higher in plaques from patients with amaurosis fugax, than in those from asymptomatic patients (P=0.029 and P=0.008 for MMP-1 and MMP-12, respectively), than in those from patients with stroke (P=0.027 and P=0.001, respectively), and than in those from patients with transient ischemic attack (P=0.046 and P=0.008, respectively).Conclusions— These data support a role of MMP-1 and -12 in determining atherosclerotic plaque stability

EFFECTS OF VITAMIN B6 DEFICIENCY ON LYMPHOID TISSUES AND HUMORAL IMMUNE RESPONSE IN RATS (IMMUNITY, PYRIDOXINE)

The influence of vitamin B(,6) deficiency on lymphoid tissues and humoral immune response in rats was assessed in two experiments. In experiment I effects of vitamin B(,6) deficiency on humoral immune response and morphological changes of sensitized lymphoid tissues were studied in growing rats. Male weanling rats (Sprague-Dawley) were divided into three treatment groups: control, restricted control and vitamin B(,6) deficient. Animals in control and vitamin B(,6) deficient groups were fed for 8 wk ad libitum a basal diet supplemented with 7 or 0 mg pyridoxine-HCl(PN-HCl)/kg, respectively. The restricted control group was fed the control diet (7 mg PN-HCl/kg) but restricted in amount to that consumed by the vitamin B(,6) deficient group on the previous day. At 7 wk, formalinized Streptococcus mutans was administered intraperitoneally. Antibody titers against S. mutans, measured by microagglutination test at 9 wk, were significantly lowered by vitamin B(,6) deficiency. Activities of IgM and IgG antibody were low in the deficient group and lymphocyte depletion was observed in thymus and paracortical regions of ileic lymph nodes. Immunized deficient rats showed no germinal centers or poorly developed ones in lymph nodes indicating their inability to respond normally to an antigenic stimulation. In experiment 2, the effect of maternal vitamin B(,6) deficiency on the developing immune system in rats was studied. Female rats (Sprague-Dawley) were fed diets containing 7, 0.6, 0, or 7 mg pyridoxine-HCl (PN-HCl)/kg during gestation and 7, 0.6, 7, or 0 mg PN-HCl/kg during lactation (groups C, MGL, DG and DL). Severe deficiency during gestation adversely affected thymus and spleen sizes of 2-day-old pups. Marginal restriction of vitamin B(,6) imposed on dams throughout gestation and lactation resulted in extremely low weights of thymus and spleen in 20-day-old pups. Severe restriction of vitamin B(,6) during lactation affected spleen weight more than thymus. After weaning, pups in groups, C, MGL, DG, and DL were fed diets containing 7, 0.6, 7, and 7 mg PN-HCl/kg, respectively. On day 42, pups of the MGL group had smaller thymuses and spleens. After 3 or 6 wk of vitamin B(,6) supplementation, weights of lymphoid tissues were restored to controls but the functional ability of ileic lymph nodes to respond to an antigenic stimulation remained impaired. Dietary restriction of vitamin B(,6) during either gestation or lactation did not significantly affect the humoral immune response of progeny. However, marginal restriction of vitamin B(,6) throughout gestation and lactation of dams and during a 21-day postweaning period of their pups resulted in depressed antibody titers of pups immunized with S. mutans