A search for absorption of Mg and Ca compounds in molecular clouds towards Galactic continuum sources

Absorption lines of MgH and CaH N = 1 − 0 transitions were searched for in foreground molecular clouds towards the continuum sources associated with Sgr B2 (M) and W49A (N). None of these lines was detected with our sensitivity level of ~20 mK. Millimetric absorption lines of MgO, MgOH, CaO and CaOH were also searched for towards Sgr B2 (M) without success. The fractional abundances relative to molecular hydrogen are ≲ 1.0 × 10−11 for MgH, ≲ 7.9 × 10−13 for MgO, ≲ 1.6 × 10−10 for MgOH, ≲ 1.6 × 10−9 for CaH, ≲ 2.0 × 10−12 for CaO, and ≲ 2.5 × 10−10 for CaOH, respectively. The low abundances measured in absorption indicate that a significant fraction of interstellar magnesium and calcium cannot be tied up in their monohydrides, monoxides and monohydroxides. The low abundance of MgH also implies that grain-surface chemistry involving magnesium is not efficient and that magnesium is depleted on to grains to a factor of ≳ 102.5 in well-shielded molecular clouds

Carbon isotope ratio in 12CO/13CO toward local molecular clouds with near-infrared high-resolution spectroscopy of vibrational transition bands

We report the carbon monoxide isotope ratio in local molecular clouds toward LkH**alpha; 101, AFGL 490, and Mon R2 IRS 3. The vibrational transition bands of 12CO **nu;=2**lt;--0 and 13CO **nu;=1**lt;--0 were observed with high-resolution near-infrared spectroscopy (R=23,000) to measure the 12CO/13CO ratio. The isotopic ratios are 12CO/13CO=137+/-9 (LkH**alpha; 101), 86+/-49 (AFGL 490), and 158 (Mon R2 IRS 3), which are 1.5-2.8 times higher than the local interstellar medium value of 12CO/13CO=57+/-5 from millimeter C18O emission observations. This is not easily explained by saturation of the 13CO absorption. It is also questionable whether the selective photodestruction of 13CO can account for the difference between the Galactic trend and the present observation, because the molecular clouds are with high visible extinction (AV=10-70 mag), well shielded from destructive FUV radiation. The molecular gas associated with AFGL 490 and Mon R2 IRS 3 consists of multiple temperature components lying in the lines of sight. In the cool component (Tex**lt;100 K), the excitation temperature of 12CO is twice that of 13CO. We attribute the temperature discrepancy to the photon-trapping effect, which makes the radiative cooling of the main isotopomer less effective. Based on data collected at Subaru Telescope, which is operated by the National Astronomical Observatory of Japan

Prognostic role of preoperative fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography with an image-based harmonization technique: A multicenter retrospective studyCentral MessagePerspective

Objectives: Despite the prognostic impacts of preoperative fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography examination, fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography–based prognosis prediction has not been used clinically because of the disparity in data between institutions. By applying an image-based harmonized approach, we evaluated the prognostic roles of fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography parameters in clinical stage I non–small cell lung cancer. Methods: We retrospectively examined 495 patients with clinical stage I non–small cell lung cancer who underwent fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography examinations before pulmonary resection between 2013 and 2014 at 4 institutions. Three different harmonization techniques were applied, and an image-based harmonization, which showed the best-fit results, was used in the further analyses to evaluate the prognostic roles of fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography parameters. Results: Cutoff values of image-based harmonized fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography parameters, maximum standardized uptake, metabolic tumor volume, and total lesion glycolysis were determined using receiver operating characteristic curves that distinguish pathologic high invasiveness of tumors. Among these parameters, only the maximum standardized uptake was an independent prognostic factor in recurrence-free and overall survivals in univariate and multivariate analyses. High image-based maximum standardized uptake value was associated with squamous histology or lung adenocarcinomas with higher pathologic grades. In subgroup analyses defined by ground-glass opacity status and histology or by clinical stages, the prognostic impact of image-based maximum standardized uptake value was always the highest compared with other fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography parameters. Conclusions: The image-based fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography harmonization was the best fit, and the image-based maximum standardized uptake was the most important prognostic marker in all patients and in subgroups defined by ground-glass opacity status and histology in surgically resected clinical stage I non–small cell lung cancers