ABSTRACT
While the number of stars in the Galactic bulge with detailed chemical abundance measurements is increasing rapidly, the inner Galactic bulge ($|b| \lt 2^{\circ }$) remains poorly studied, ...due to heavy interstellar absorption and photometric crowding. We have carried out a high-resolution IR spectroscopic study of 72 M giants in the inner bulge using the CRIRES (ESO/VLT) facility. Our spectra cover the wavelength range of 2.0818–2.1444 $\mu $m with the resolution of R ∼ 50 000 and have signal-to-noise ratio of 50:100. Our stars are located along the bulge minor axis at l = 0°, b= ±0°, ±1°, ±2°, and +3°. Our sample was analysed in a homogeneous way using the most current K-band line list. We clearly detect a bimodal metallicity distribution function with a metal-rich peak at $\rm \sim +0.3\,dex$ and a metal-poor peak at $\rm \sim -0.5\,dex$ and no stars with Fe/H > +0.6 dex. The Galactic Centre field reveals in contrast a mainly metal-rich population with a mean metallicity of $\rm +0.3\,dex$. We derived Mg/Fe and Si/Fe abundances that are consistent with trends from the outer bulge. We confirm for the supersolar metallicity stars the decreasing trend in Mg/Fe and Si/Fe as expected from chemical evolution models. With the caveat of a relatively small sample, we do not find significant differences in the chemical abundances between the Northern and the Southern fields; hence, the evidence is consistent with symmetry in chemistry between North and South.
To develop a bounding-box-based 3D convolutional neural network (CNN) for user-guided volumetric pancreas ductal adenocarcinoma (PDA) segmentation.
Reference segmentations were obtained on CTs ...(2006–2020) of treatment-naïve PDA. Images were algorithmically cropped using a tumor-centered bounding box for training a 3D nnUNet-based-CNN. Three radiologists independently segmented tumors on test subset, which were combined with reference segmentations using STAPLE to derive composite segmentations. Generalizability was evaluated on Cancer Imaging Archive (TCIA) (n = 41) and Medical Segmentation Decathlon (MSD) (n = 152) datasets.
Total 1151 patients 667 males; age:65.3 ± 10.2 years; T1:34, T2:477, T3:237, T4:403; mean (range) tumor diameter:4.34 (1.1–12.6)-cm were randomly divided between training/validation (n = 921) and test subsets (n = 230; 75% from other institutions). Model had a high DSC (mean ± SD) against reference segmentations (0.84 ± 0.06), which was comparable to its DSC against composite segmentations (0.84 ± 0.11, p = 0.52). Model-predicted versus reference tumor volumes were comparable (mean ± SD) (29.1 ± 42.2-cc versus 27.1 ± 32.9-cc, p = 0.69, CCC = 0.93). Inter-reader variability was high (mean DSC 0.69 ± 0.16), especially for smaller and isodense tumors. Conversely, model's high performance was comparable between tumor stages, volumes and densities (p > 0.05). Model was resilient to different tumor locations, status of pancreatic/biliary ducts, pancreatic atrophy, CT vendors and slice thicknesses, as well as to the epicenter and dimensions of the bounding-box (p > 0.05). Performance was generalizable on MSD (DSC:0.82 ± 0.06) and TCIA datasets (DSC:0.84 ± 0.08).
A computationally efficient bounding box-based AI model developed on a large and diverse dataset shows high accuracy, generalizability, and robustness to clinically encountered variations for user-guided volumetric PDA segmentation including for small and isodense tumors.
AI-driven bounding box-based user-guided PDA segmentation offers a discovery tool for image-based multi-omics models for applications such as risk-stratification, treatment response assessment, and prognostication, which are urgently needed to customize treatment strategies to the unique biological profile of each patient's tumor.
Cutaneous leishmaniasis (CL), a neglected tropical disease, is reported to be prevalent in tribal villages located in the Agasthyamala Biosphere Reserve forests of Western Ghats, Kerala state, India. ...We carried out an investigation to characterize the species of Leishmania parasites involved in these infections prevalent among one of the oldest human tribal populations in India. Skin aspirates collected from 13 clinically diagnosed cases were subjected to histopathological investigations, serological rapid tests using 'rk39' and molecular diagnostics. Clinical manifestations recorded among the patients were hypo-pigmented erythematous nodules/papules on limbs and other parts of the body. Histopathological investigations of these skin lesions among patients showed Leishman-Donovan bodies in macrophages. None of the patients were found to be positive for rk39 tests, which detect active visceral leishmaniasis. Using three different genetic markers kinetoplast minicircle DNA, 3' UTR region of heat-shock protein 70 (Hsp70) and Hsp70 gene we identified the parasite species involved in these infections to be Leishmania donovani. The 6-phosphogluconate (6-PGDH) gene sequences of the parasite isolates from Western Ghats indicated close genetic relatedness to L. donovani isolates reported from Sri Lanka, also causing CL. This could be cited as another instance of 'local endemism' of organisms in this single 'bio-geographic unit'.
ABSTRACT We present a multiwavelength investigation of star formation activity toward the southern H ii regions associated with IRAS 17160-3707, located at a distance of 6.2 kpc with a bolometric ...luminosity of 8.3 × 105 L . The ionized gas distribution and dust clumps in the parental molecular cloud are examined in detail using measurements at infrared, submillimeter and radio wavelengths. The radio continuum images at 1280 and 610 MHz obtained using the Giant Metrewave Radio Telescope reveal the presence of multiple compact sources as well as nebulous emission. At submillimeter wavelengths, we identify seven dust clumps and estimate their physical properties such as temperature: 24-30 K, mass: 300-4800 M and luminosity: 9-317 × 102 L using modified blackbody fits to the spectral energy distributions (SEDs) between 70 and 870 m. We find 24 young stellar objects (YSOs) in the mid-infrared, with a few of them coincident with the compact radio sources. The SEDs of the YSOs have been fitted by the Robitaille models and the results indicate that those having radio compact sources as counterparts host massive objects in early evolutionary stages with best fit age ≤0.2 Myr. We compare the relative evolutionary stages of clumps using various signposts such as masers, ionized gas, presence of YSOs and infrared nebulosity, and find six massive star-forming clumps and one quiescent clump. Of the former, five are in a relatively advanced stage and one in an earlier stage.
Context. The central molecular zone (CMZ) is a ~200 pc region around the Galactic centre. The study of star formation in the central part of the Milky Way is of great interest as it provides a ...template for the closest galactic nuclei. Aims. We present a spectroscopic follow-up of photometrically selected young stellar object (YSO) candidates in the CMZ of the Galactic centre. Our goal is to quantify the contamination of this YSO sample by reddened giant stars with circumstellar envelopes and to determine the star formation rate (SFR) in the CMZ. Methods. We obtained KMOS low-resolution near-infrared spectra (R ~ 4000) between 2.0 and 2.5 μm of sources, many of which have been previously identified by mid-infrared photometric criteria as massive YSOs in the Galactic centre. Our final sample consists of 91 stars with good signal-to-noise ratio. We separated YSOs from cool late-type stars based on spectral features of CO and Brγ at 2.3 μm and 2.16 μm, respectively. We made use of spectral energy distribution (SED) model fits to the observed photometric data points from 1.25 to 24 μm to estimate approximate masses for the YSOs. Results. Using the spectroscopically identified YSOs in our sample, we confirm that existing colour–colour diagrams and colour-magnitude diagrams are unable to efficiently separate YSOs and cool late-type stars. In addition, we define a new colour–colour criterion that separates YSOs from cool late-type stars in the H−KS vs. H −8.0 diagram. We use this new criterion to identify YSO candidates in the |l| < 1.̊5, |b| < 0.̊5, region and use model SED fits to estimate their approximate masses. By assuming an appropriate initial mass function (IMF) and extrapolating the stellar IMF down to lower masses, we determine a SFR of ~0.046 ± 0.026 M⊙ yr-1 assuming an average age of 0.75 ± 0.25 Myr for the YSOs. This value is lower than estimates found using the YSO counting method in the literature. Conclusions. Our SFR estimate in the CMZ agrees with the previous estimates from various methods and reaffirms that star formation in the CMZ is proceeding at a lower rate than predicted by various star forming models.
Introduction
The aim of this prospective human trial was to evaluate the clinical performance of a novel THUNDERBEAT (TB) energy device in laparoscopic colon surgery. This study reports the first ...human trial in USA with this combined energy device in colon surgery.
Methods and procedures
This is a prospective pilot study with 30 subjects undergoing left or right laparoscopic colon resection for neoplasm in a single institution. All soft tissue dissections and all vessel ligations were performed using TB. No other energy device was used within the abdomen. Recorded end-points were dissection time (from the start of colon mobilization to specimen removal), surgical procedure time, the number of times TB taken out of the abdominal cavity, intraoperative complications (bleeding at the time of mesenteric dissection or vessel ligation, thermal injury during surgery, injury of other organs), technical device problems, postoperative complications (bleeding, delayed thermal injuries, other complications within 30 days), length of hospital stay, and mortality.
Results
Thirty subjects (15 males) were enrolled in the study with median age and range 68.5 (21–86) and BMI kg/m
2
25.5 (20–35). Twelve subjects underwent right and 18 left laparoscopic hemicolectomy. The mean surgical procedure time was 163 ± 86 min and for dissection using TB device 80.6 ± 35 min. Major vessel ligation was successful in all subjects. The median number of TB applications to seal inferior mesenteric artery was 3 (2–8). TB was taken out of the abdominal cavity during dissection for tip cleaning a medium number of two times/per case. No intraoperative or postoperative complications (bleeding, thermal injuries, etc.) related to use of TB were noted.
Conclusions
The TB device demonstrated efficient and successful performance at tissue dissection and vessel ligation in left and right colectomies. TB technology can be employed in complex abdominal surgery and may save time through faster dissection but comparative studies with other energy devices are needed to confirm this.
Purpose and background: Isocitrate dehydrogenase (IDH) mutation and O-6 methyl guanine methyl transferase (MGMT) methylation are surrogate biomarkers of improved survival in gliomas. This study aims ...at studying the ability of semantic magnetic resonance imaging (MRI) features to predict the IDH mutation status confirmed by the gold standard molecular tests. Methods: The MRI of 148 patients were reviewed for various imaging parameters based on the Visually AcceSAble Rembrandt Images (VASARI) study. Their IDH status was determined using immunohistochemistry (IHC). Fisher’s exact or chi-square tests for univariate and logistic regression for multivariate analysis were used. Results: Parameters such as mild and patchy enhancement, minimal edema, necrosis < 25%, presence of cysts, and less rCBV (relative cerebral blood volume) correlated with IDH mutation. The median age of IDH-mutant and IDH-wild patients were 34 years (IQR: 29−43) and 52 years (IQR: 45−59), respectively. Mild to moderate enhancement was observed in 15/19 IDH-mutant patients (79%), while 99/129 IDH-wildtype (77%) had severe enhancement (p-value <0.001). The volume of edema with respect to tumor volume distinguished IDH-mutants from wild phenotypes (peritumoral edema volume < tumor volume was associated with higher IDH-mutant phenotypes; p-value < 0.025). IDH-mutant patients had a median rCBV value of 1.8 (IQR: 1.4−2.0), while for IDH-wild phenotypes, it was 2.6 (IQR: 1.9−3.5) {p-value = 0.001}. On multivariate analysis, a cut-off of 25% necrosis was able to differentiate IDH-mutant from IDH-wildtype (p-value < 0.001), and a cut-off rCBV of 2.0 could differentiate IDH-mutant from IDH-wild phenotypes (p-value < 0.007). Conclusion: Semantic imaging features could reliably predict the IDH mutation status in high-grade gliomas. Presurgical prediction of IDH mutation status could help the treating oncologist to tailor the adjuvant therapy or use novel IDH inhibitors.
Abstract
Splenium of corpus callosum can be involved in a variety of pathologies causing reversible or irreversible damage. Magnetic resonance imaging (MRI) is a useful investigation to evaluate the ...same. In spite of the differing etiologies implicated, MRI findings can be quite common. We review the reversible causes of diffusion restriction involving the splenium of corpus callosum and highlight the etiopathologic mechanisms implicated in these pathologies. We further discuss these pathologies in entirety with relevant clinical and laboratory findings helping make definitive diagnosis and guiding appropriate management.
M giants with IGRINS Nandakumar, G.; Ryde, N.; Mace, G.
Astronomy and astrophysics (Berlin),
08/2023, Volume:
676
Journal Article
Peer reviewed
Open access
Context.
The origin and evolution of fluorine in the Milky Way Galaxy is still under debate. In particular, the increase in the F/Fe in metal-rich stars found from near-IR HF lines is challenging to ...explain theoretically. Chemical evolution models with current knowledge of yields from different fluorine-producing stellar sources cannot reproduce these observations.
Aims.
The aim of this work is to observationally study the Galactic chemical evolution of fluorine, especially for metal-rich stars. We want to investigate whether the significant rise in fluorine production at high metallicities can be corroborated. Furthermore, we want to explore the possible reasons for this upturn in F/Fe.
Methods.
We determined the fluorine abundances from 50 M giants (3300 <
T
eff
< 3800 K) in the solar neighborhood spanning a broad range of metallicities (−0.9 < Fe/H < 0.25 dex). These stars are cool enough to have an array of lines from the HF molecule in the
K
band. We observed the stars with the Immersion GRating INfrared Spectrograph (IGRINS) spectrometer mounted on the Gemini South telescope and on the
Harlan J. Smith
Telescope at McDonald Observatory and investigate each of 10 HF molecular lines in detail.
Results.
Based on a detailed line-by-line analysis of ten HF lines, we find that the R19, R18, and R16 lines (22 699.49, 22 714.59, and 22 778.25 Å) should primarily be used for an abundance analysis. The R15, R14, and R13 lines at 22 826.86, 22 886.73, and 22 957.94 Å can also be used, but the trends based on these lines show increasing dependence on the stellar parameters. The strongest HF lines, namely R12, R11, R9, and R7 lying at 23 040.57, 23 134.76, 23 358.33, and 23 629.99 Å should be avoided. The abundances derived from these strongest lines show significant trends with the stellar parameters, as well as a high sensitivity to variations in the stellar microturbulence, especially for coolest and most metal-rich stars. This leads to a huge scatter and high fluorine abundances for supersolar metallicity stars, not seen in the trends from the weaker lines for the same stars.
Conclusions.
When estimating the final mean fluorine abundance trend as a function of metallicity, we neglect the fluorine abundances from the four strongest lines (R7, R9, R11, and R12) for all stars and use only those derived from R16, R18, and R19 for the coolest and most metal-rich stars. We confirm the flat trend of F/Fe found in other studies for stars in the metallicity range of −1.0 < Fe/H < 0.0 dex. We also find a slight enhancement at super-solar metallicities (0 < Fe/H < 0.15 dex) but we cannot confirm the upward trend seen at Fe/H > 0.25 dex. The HF line is intrinsically temperature sensitive, which calls for studies of stars with highly accurate and homogeneous stellar parameters. The spread in our trend is presumably caused by the temperature sensitivity. We need more observations of M giants at super-solar metallicities with a spectrometer that covers as many of the HF lines as possible, for instance the IGRINS spectrometer, to confirm whether the metal-rich fluorine abundance upturn is real or not.
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