495 research outputs found
N-H...N Hydrogen Bonding in the Four Independent Molecules of (2S,4S,5R)-(-)-2-(1H-Imidazol-2-yl)-3,4-dimethyl-5-phenyl-1,3-oxazolidine, with C-H...πarene, C-H...O and C-H...πC=C Interactions
The title compound, C₁₄H ₁₇N₃ O, prepared from (1R,2S)-
(-)-ephedrine, crystallizes in space group P2₁ with four
molecules in the asymmetric unit. The molecules, in
pairs, take part in intermolecular N--H...N hydrogen bonding between the imidazolyl rings, forming one-dimensional
chains with alternating N...N distances of
2.866 (3)/2.883(3) and 2.945 (3)/2.956(3)Å. Inter-chain
Carene--H...πarene, Carene--H...O and Csp3--H...πc=
interactions generate a three-dimensional network
A Tale of Two Tails: Exploring Stellar Populations in the Tidal Tails of NGC 3256
We have developed an observing program using deep, multiband imaging to probe
the chaotic regions of tidal tails in search of an underlying stellar
population, using NGC 3256's 400 Myr twin tidal tails as a case study. These
tails have different colours of and for NGC 3256W, and and
for NGC 3256E, indicating different stellar populations. These colours
correspond to simple stellar population ages of Myr and
Myr for NGC 3256W and NGC 3256E, respectively, suggesting
NGC 3256W's diffuse light is dominated by stars formed after the interaction,
while light in NGC 3256E is primarily from stars that originated in the host
galaxy. Using a mixed stellar population model, we break our diffuse light into
two populations: one at 10 Gyr, representing stars pulled from the host
galaxies, and a younger component, whose age is determined by fitting the model
to the data. We find similar ages for the young populations of both tails,
( and Myr for NGC 3256W and NGC 3256E,
respectively), but a larger percentage of mass in the 10 Gyr population for NGC
3256E ( vs ). Additionally, we detect 31 star
cluster candidates in NGC 3256W and 19 in NGC 2356E, with median ages of 141
Myr and 91 Myr, respectively. NGC 3256E contains several young (< 10 Myr), low
mass objects with strong nebular emission, indicating a small, recent burst of
star formation.Comment: Accepted for publication in MNRAS. 16 pages, 19 figure
Gemini Spectroscopic Survey of Young Star Clusters in Merging/Interacting Galaxies. IV. Stephan's Quintet
We present a spectroscopic survey of 21 young massive clusters and complexes
and one tidal dwarf galaxy candidate (TDG) in Stephan's Quintet, an interacting
compact group of galaxies. All of the selected targets lie outside the main
galaxies of the system and are associated with tidal debris. We find clusters
with ages between a few and 125 Myr and confirm the ages estimated through HST
photometry by Fedotov et al. (2011), as well as their modelled interaction
history of the Quintet. Many of the clusters are found to be relatively
long-lived, given their spectrosopically derived ages, while their high masses
suggest that they will likely evolve to eventually become intergalactic
clusters. One cluster, T118, is particularly interesting, given its age (\sim
125 Myr), high mass (\sim 2\times10^6 M\odot) and position in the extreme outer
end of the young tidal tail. This cluster appears to be quite extended (Reff
\sim 12 - 15 pc) compared to clusters observed in galaxy disks (Reff \sim 3 - 4
pc), which confirms an effect we previously found in the tidal tails of NGC
3256, where clusters are similarly extended. We find that star and cluster
formation can proceed at a continuous pace for at least \sim 150 Myr within the
tidal debris of interacting galaxies. The spectrum of the TDG candidate is
dominated by a young population (\sim 7 Myr), and assuming a single age for the
entire region, has a mass of at least 10^6 M\odot.Comment: 37 pages, 10 Figures, 7 Tabl
Targeted transperineal biopsy of the prostate has limited additional benefit over background cores for larger MRI-identified tumors.
PURPOSE: To compare histological outcomes in patients undergoing MRI-transrectal ultrasound fusion transperineal (MTTP) prostate biopsy and determine the incremental benefit of targeted cores. METHODS: Seventy-six consecutive patients with 89 MRI-identified targets underwent MTTP biopsy. Separate targeted biopsies and background cores were obtained according to a standardized protocol. Target biopsies were considered of added diagnostic value if these cores showed a higher Gleason grade than non-targeted cores taken from the same sector (Group 1, n = 41). Conversely, where background cores demonstrated an equal or higher Gleason grade, target cores were considered to be non-beneficial (Group 2, n = 48). RESULTS: There was no significant difference in age, PSA, prostate volume, time-to-biopsy, and number of cores obtained between the groups. A greater proportion of target cores were positive for cancer (158/228; 69.3 %) compared to background (344/1881; 18.38 %). The median target volume was 0.54 cm(3) for Group 1 (range 0.09-2.79 cm(3)) and 1.65 cm(3) for Group 2 (0.3-9.07 cm(3)), p 1.0 cm.The authors acknowledge research support from Cancer Research UK, National Institute of Health Research Cambridge Biomedical Research Centre, Cancer Research UK and the Engineering and Physical Sciences Research Council Imaging Centre in Cambridge and Manchester and the Cambridge Experimental Cancer Medicine Centre.This is the final version of the article. It first appeared from Springer via http://dx.doi.org/10.1007/s00345-015-1650-
Comparison of initial and tertiary centre second opinion reads of multiparametric magnetic resonance imaging of the prostate prior to repeat biopsy.
OBJECTIVES: To investigate the value of second-opinion evaluation of multiparametric prostate magnetic resonance imaging (MRI) by subspecialised uroradiologists at a tertiary centre for the detection of significant cancer in transperineal fusion prostate biopsy. METHODS: Evaluation of prospectively acquired initial and second-opinion radiology reports of 158 patients who underwent MRI at regional hospitals prior to transperineal MR/untrasound fusion biopsy at a tertiary referral centre over a 3-year period. Gleason score (GS) 7-10 cancer, positive predictive value (PPV) and negative (NPV) predictive value (±95 % confidence intervals) were calculated and compared by Fisher's exact test. RESULTS: Disagreement between initial and tertiary centre second-opinion reports was observed in 54 % of cases (86/158). MRIs had a higher NPV for GS 7-10 in tertiary centre reads compared to initial reports (0.89 ± 0.08 vs 0.72 ± 0.16; p = 0.04), and a higher PPV in the target area for all cancer (0.61 ± 0.12 vs 0.28 ± 0.10; p = 0.01) and GS 7-10 cancer (0.43 ± 0.12 vs 0.2 3 ± 0.09; p = 0.02). For equivocal suspicion, the PPV for GS 7-10 was 0.12 ± 0.11 for tertiary centre and 0.11 ± 0.09 for initial reads; p = 1.00. CONCLUSIONS: Second readings of prostate MRI by subspecialised uroradiologists at a tertiary centre significantly improved both NPV and PPV. Reporter experience may help to reduce overcalling and avoid overtargeting of lesions. KEY POINTS: • Multiparametric MRIs were more often called negative in subspecialist reads (41 % vs 20 %). • Second readings of prostate mpMRIs by subspecialist uroradiologists significantly improved NPV and PPV. • Reporter experience may reduce overcalling and avoid overtargeting of lesions. • Greater education and training of radiologists in prostate MRI interpretation is advised.RWTH Aachen University Hospital (Aachen, Germany), National Institute for Health Research Cambridge Biomedical Research Centre, Cancer Research UK, Engineering and Physical Sciences Research Council Imaging Centre in Cambridge and Manchester, Cambridge Experimental Cancer Medicine Centr
Testing an Integrated Dual Diathesis-Threat Model of Authoritarianism
The Dual Diathesis-Threat Model of Authoritarianism proposes parallel motivational pathways by which similar personality features could predispose liberals and conservatives to different forms of authoritarianism. Specifically, the model posits that cognitive rigidity serves as a shared dispositional ‘diathesis’ of right- and left-wing authoritarianism ‘activated’ by distinct threats. For cognitively rigid conservatives, threats of change (i.e., threats to cohesion/conventions, cultural shifts) were expected to enhance the embrace of RWA; while for cognitively rigid liberals, threats to change (i.e., oppression, inequities, barriers to social progress) were predicted to promote LWA. Two studies examined this premise. In Study One, American citizens (N=256) of different political backgrounds reported qualitatively distinct threats and differently ranked a series of threats. Thematic content analysis revealed that for liberals (n=124), concerns about climate change, MAGA, inequality, poverty, and prejudice were preeminent, whereas for conservatives (n=70), issues like immigration, crime, war, terrorism, and perceived cultural decline were front of mind. Conservatives and liberals consistently, but not exclusively, framed their responses in terms of threats of and to change. Moderates (n=62) were particularly concerned about social and political division; overall, however, moderates’ responses and threat rankings paralleled conservatives’. Respondents were uniformly threatened by economic issues and their political opponents, the latter of whom were the top-ranked threats across ideological groups (for liberals, MAGA; for conservatives and moderates, the Woke Mob). Study Two tested the DDT model in a combined sample (N=465) of American undergraduates (n=206) and laypeople (n=259) using an experimental manipulation of threat of and to change. Hypotheses were partially supported, but there was little support for the DDT framework as a whole. Cognitive rigidity and threats of and to change predicted greater endorsement of authoritarian responses. However, these effects were not particular to conservatives or liberals. Moreover, a two-way interaction between cognitive rigidity and political ideology suggested that high cognitive rigidity enhanced authoritarianism among liberals, but not conservatives. Implications for the theoretical landscape are discussed, and directions proposed for future research
The MyD88+ phenotype is an adverse prognostic factor in epithelial ovarian cancer
The prognosis of epithelial ovarian cancer is poor in part due to the high frequency of chemoresistance. Recent evidence points to the Toll-like receptor-4 (TLR4), and particularly its adaptor protein MyD88, as one potential mediator of this resistance. This study aims to provide further evidence that MyD88 positive cancer cells are clinically significant, stem-like and reproducibly detectable for the purposes of prognostic stratification. Expression of TLR4 and MyD88 was assessed immunohistochemically in 198 paraffin-embedded ovarian tissues and in an embryonal carcinoma model of cancer stemness. In parallel, expression of TLR4 and MyD88 mRNA and regulatory microRNAs (miR-21 and miR-146a) was assessed, as well as in a series of chemosensitive and resistant cancer cells lines. Functional analysis of the pathway was assessed in chemoresistant SKOV-3 ovarian cancer cells. TLR4 and MyD88 expression can be reproducibly assessed via immunohistochemistry using a semi-quantitative scoring system. TLR4 expression was present in all ovarian epithelium (normal and neoplastic), whereas MyD88 was restricted to neoplastic cells, independent of tumour grade and associated with reduced progression-free and overall survival, in an immunohistological specific subset of serous carcinomas, p<0.05. MiR-21 and miR-146a expression was significantly increased in MyD88 negative cancers (p<0.05), indicating their participation in regulation. Significant alterations in MyD88 mRNA expression were observed between chemosensitive and chemoresistant cells and tissue. Knockdown of TLR4 in SKOV-3 ovarian cells recovered chemosensitivity. Knockdown of MyD88 alone did not. MyD88 expression was down-regulated in differentiated embryonal carcinoma (NTera2) cells, supporting the MyD88+ cancer stem cell hypothesis. Our findings demonstrate that expression of MyD88 is associated with significantly reduced patient survival and altered microRNA levels and suggest an intact/functioning TLR4/MyD88 pathway is required for acquisition of the chemoresistant phenotype. Ex vivo manipulation of ovarian cancer stem cell (CSC) differentiation can decrease MyD88 expression, providing a potentially valuable CSC model for ovarian cancer
Raman Spectroscopy identifies differences in ochronotic and non-ochronotic cartilage:a potential novel technique for monitoring ochronosis
Objective Alkaptonuria (AKU) is a rare, inherited disorder of tyrosine metabolism, where patients are unable to breakdown homogentisic acid (HGA), which increases systemically over time. It presents with a clinical triad of features; HGA in urine, ochronosis of collagenous tissues, and the subsequent ochronotic arthritis of these tissues. In recent years the advance in the understanding of the disease and the potential treatment of the disorder looks promising with the data on the efficacy of nitisinone. However, there are limited methods for the detection and monitoring of ochronosis in vivo, or for treatment monitoring. The study aim was to test the hypothesis that Raman spectra would identify a distinct chemical fingerprint for the non-ochronotic, compared to ochronotic cartilage. Design: Ochronotic and non-ochronotic cartilage from human hips and ears were analysed using Raman spectroscopy. Results: Non-ochronotic cartilage spectra were similar and reproducible and typical of normal articular cartilage. Conversely, the ochronotic cartilage samples were highly fluorescent and displayed limited or no discernible Raman peaks in the spectra, in stark contrast to their non-ochronotic pairs. Interestingly, a novel peak was observed associated with the polymer of HGA in the ochronotic cartilage that was confirmed by analysis of pigment derived from synthetic HGA. Conclusion: This technique reveals novel data on the chemical differences in ochronotic compared with non-ochronotic cartilage, these differences are detectable by a technique that is already generating in vivo data and demonstrates the first possible procedure to monitor the progression of ochronosis in tissues of patients with AKU
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