First observation of electric-quadrupole infrared transitions in water vapour

Molecular absorption of infrared radiation is generally due to ro-vibrational electric-dipole transitions. Electric-quadrupole transitions may still occur, but they are typically a million times weaker than electric-dipole transitions, rendering their observation extremely challenging. In polyatomic or polar diatomic molecules, ro-vibrational quadrupole transitions have never been observed. Here, we report the first direct detection of quadrupole transitions in water vapor. The detected quadrupole lines have intensity largely above the standard dipole intensity cut-off of spectroscopic databases and thus are important for accurate atmospheric and astronomical remote sensing

Communication: Saturated CO 2

International audienc

ANTIMICROBIAL PROFILES, ANTIDIARRHEAL AND ANTIPYRETIC CAPACITIES OF PHENOL ACID RICH-FRACTIONS FROM XIMENIA AMERICA L., (OLACACEAE) IN WISTAR ALBINO RATS

Objective: The present study aim to evaluate antimicrobial and antidiarrheal activities of phenol acid-rich fractions of roots from Ximenia americana L., in animal models in order to confirm the ethnomedicinal use of Ximenia Americana L., roots.Methods: In vitro antibacterial (Minimum inhibitory concentration (MIC), Minimum bactericidal concentration (MBC) and time-kill studies) of phenol-rich fractions of roots from Ximenia americana L., was assessed using eight bacteria strains (Gram-negative). The anti-diarrheal activity was evaluated using castor using castor oil induced diarrhea whereas Anti-secretory activity was investigated using castor oil-induced enteropooling assay examined in animal models respectively.Results: All test bacteria were susceptible to the phenol-rich fractions. Time-kill results showed that after 5 h exposition there was no viable microorganism in the initial inoculum. Moreover, phenol acid-rich fractions of roots (100-200 and 300 mg/kg, p. o.) produced dose-dependent and significant (p<0.05-0.001) protection of rats against castor oil-induced diarrhea, and delayed gastric emptying. Phenol acid-rich fractions of roots, dose-dependently and significantly (p<0.05-0.001) delayed the onset of castor oil induced diarrhea, decreased the frequency of defecation, and reduced the severity of diarrhea in the rats. Phenol acid-rich fractions caused dose-related inhibition of castor-oil-induced enteropooling in rats.Conclusion: The data analysis indicates that the tested of phenol-rich fractions has significant effects when compared with the standard antibiotic. These results, therefore, justify the traditional use of Ximenia americana L. About antidiarrheal activity, the findings of this study indicate that phenol acid-rich fraction possesses antidiarrheal property in rats. These findings confirm the ethnomedicinal use of Ximenia americana L., roots valuable natural remedy for the treatment, management and/or control of diarrhea

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

Vitamin D deficiency causes inward hypertrophic remodeling and alters vascular reactivity of rat cerebral arterioles

BACKGROUND AND PURPOSE: Vitamin D deficiency (VDD) is a global health problem, which can lead to several pathophysiological consequences including cardiovascular diseases. Its impact on the cerebrovascular system is not well understood. The goal of the present work was to examine the effects of VDD on the morphological, biomechanical and functional properties of cerebral arterioles. METHODS: Four-week-old male Wistar rats (n = 11 per group) were either fed with vitamin D deficient diet or received conventional rat chow with per os vitamin D supplementation. Cardiovascular parameters and hormone levels (testosterone, androstenedione, progesterone and 25-hydroxyvitamin D) were measured during the study. After 8 weeks of treatment anterior cerebral artery segments were prepared and their morphological, biomechanical and functional properties were examined using pressure microangiometry. Resorcin-fuchsin and smooth muscle actin staining were used to detect elastic fiber density and smooth muscle cell counts in the vessel wall, respectively. Sections were immunostained for eNOS and COX-2 as well. RESULTS: VDD markedly increased the wall thickness, the wall-to-lumen ratio and the wall cross-sectional area of arterioles as well as the number of smooth muscle cells in the tunica media. As a consequence, tangential wall stress was significantly lower in the VDD group. In addition, VDD increased the myogenic as well as the uridine 5'-triphosphate-induced tone and impaired bradykinin-induced relaxation. Decreased eNOS and increased COX-2 expression were also observed in the endothelium of VDD animals. CONCLUSIONS: VDD causes inward hypertrophic remodeling due to vascular smooth muscle cell proliferation and enhances the vessel tone probably because of increased vasoconstrictor prostanoid levels in young adult rats. In addition, the decreased eNOS expression results in endothelial dysfunction. These morphological and functional alterations can potentially compromise the cerebral circulation and lead to cerebrovascular disorders in VDD