Background
This multicentre cohort study sought to define a robust pathological indicator of clinically meaningful response to neoadjuvant chemotherapy in oesophageal adenocarcinoma.
Methods
A ...questionnaire was distributed to 11 UK upper gastrointestinal cancer centres to determine the use of assessment of response to neoadjuvant chemotherapy. Records of consecutive patients undergoing oesophagogastric resection at seven centres between January 2000 and December 2013 were reviewed. Pathological response to neoadjuvant chemotherapy was assessed using the Mandard Tumour Regression Grade (TRG) and lymph node downstaging.
Results
TRG (8 of 11 centres) was the most widely used system to assess response to neoadjuvant chemotherapy, but there was discordance on how it was used in practice. Of 1392 patients, 1293 had TRG assessment; data were available for clinical and pathological nodal status (cN and pN) in 981 patients, and TRG, cN and pN in 885. There was a significant difference in survival between responders (TRG 1–2; median overall survival (OS) not reached) and non‐responders (TRG 3–5; median OS 2·22 (95 per cent c.i. 1·94 to 2·51) years; P < 0·001); the hazard ratio was 2·46 (95 per cent c.i. 1·22 to 4·95; P = 0·012). Among local non‐responders, the presence of lymph node downstaging was associated with significantly improved OS compared with that of patients without lymph node downstaging (median OS not reached versus 1·92 (1·68 to 2·16) years; P < 0·001).
Conclusion
A clinically meaningful local response to neoadjuvant chemotherapy was restricted to the small minority of patients (14·8 per cent) with TRG 1–2. Among local non‐responders, a subset of patients (21·3 per cent) derived benefit from neoadjuvant chemotherapy by lymph node downstaging and their survival mirrored that of local responders.
Response associated with survival
The XMM Cluster Survey (XCS) is a serendipitous search for galaxy clusters using all publicly available data in the XMM-Newton Science Archive. Its main aims are to measure cosmological parameters ...and trace the evolution of X-ray scaling relations. In this paper we present the first data release from the XMM Cluster Survey (XCS-DR1). This consists of 503 optically confirmed, serendipitously detected, X-ray clusters. Of these clusters, 256 are new to the literature and 357 are new X-ray discoveries. We present 463 clusters with a redshift estimate (0.06 < z < 1.46), including 261 clusters with spectroscopic redshifts. The remainder have photometric redshifts. In addition, we have measured X-ray temperatures (T
X) for 401 clusters (0.4 < T
X < 14.7 keV). We highlight seven interesting subsamples of XCS-DR1 clusters: (i) 10 clusters at high redshift (z > 1.0, including a new spectroscopically confirmed cluster at z= 1.01); (ii) 66 clusters with high T
X (>5 keV); (iii) 130 clusters/groups with low T
X (<2 keV); (iv) 27 clusters with measured T
X values in the Sloan Digital Sky Survey (SDSS) 'Stripe 82' co-add region; (v) 77 clusters with measured T
X values in the Dark Energy Survey region; (vi) 40 clusters detected with sufficient counts to permit mass measurements (under the assumption of hydrostatic equilibrium); (vii) 104 clusters that can be used for applications such as the derivation of cosmological parameters and the measurement of cluster scaling relations. The X-ray analysis methodology used to construct and analyse the XCS-DR1 cluster sample has been presented in a companion paper, Lloyd-Davies et al.
Studies of the X-ray surface brightness profiles of clusters, coupled with theoretical considerations, suggest that the breaking of self-similarity in the hot gas results from an ‘entropy floor’, ...established by some heating process, which affects the structure of the intracluster gas strongly in lower-mass systems. By fitting analytical models for the radial variation in gas density and temperature to X-ray spectral images from the ROSAT PSPC and ASCA GIS, we have derived gas entropy profiles for 20 galaxy clusters and groups. We show that, when these profiles are scaled such that they should lie on top of one another in the case of self-similarity, the lowest-mass systems have higher-scaled entropy profiles than more massive systems. This appears to be due to a baseline entropy of depending on the extent to which shocks have been suppressed in low-mass systems. The extra entropy may be present in all systems, but is detectable only in poor clusters, where it is significant compared with the entropy generated by gravitational collapse. This excess entropy appears to be distributed uniformly with radius outside the central cooling regions. We determine the energy associated with this entropy floor, by studying the net reduction in binding energy of the gas in low-mass systems, and find that it corresponds to a pre-heating temperature of ∼0.3 keV. Since the relationship between entropy and energy injection depends upon gas density, we are able to combine the excesses of 70–140 keV cm2 and 0.3 keV to derive the typical electron density of the gas into which the energy was injected. The resulting value of implies that the heating must have happened prior to cluster collapse but after a redshift z∼7–10. The energy requirement is well matched to the energy from supernova explosions responsible for the metals which now pollute the intracluster gas.
The XMM Cluster Survey: X-ray analysis methodology Lloyd-Davies, E. J.; Romer, A. Kathy; Mehrtens, Nicola ...
Monthly notices of the Royal Astronomical Society,
November 2011, Letnik:
418, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The XMM Cluster Survey (XCS) is a serendipitous search for galaxy clusters using all publicly available data in the XMM-Newton Science Archive. Its main aims are to measure cosmological parameters ...and trace the evolution of X-ray scaling relations. In this paper we describe the data processing methodology applied to the 5776 XMM observations used to construct the current XCS source catalogue. A total of 3675 > 4σ cluster candidates with >50 background-subtracted X-ray counts are extracted from a total non-overlapping area suitable for cluster searching of 410 deg2. Of these, 993 candidates are detected with >300 background-subtracted X-ray photon counts, and we demonstrate that robust temperature measurements can be obtained down to this count limit. We describe in detail the automated pipelines used to perform the spectral and surface brightness fitting for these candidates, as well as to estimate redshifts from the X-ray data alone. A total of 587 (122) X-ray temperatures to a typical accuracy of <40 (<10) per cent have been measured to date. We also present the methodology adopted for determining the selection function of the survey, and show that the extended source detection algorithm is robust to a range of cluster morphologies by inserting mock clusters derived from hydrodynamical simulations into real XMMimages. These tests show that the simple isothermal β-profiles is sufficient to capture the essential details of the cluster population detected in the archival XMM observations. The redshift follow-up of the XCS cluster sample is presented in a companion paper, together with a first data release of 503 optically confirmed clusters.
We integrated multiple behavioural and developmental measures from multiple time-points using machine learning to improve early prediction of individual Autism Spectrum Disorder (ASD) outcome. We ...examined Mullen Scales of Early Learning, Vineland Adaptive Behavior Scales, and early ASD symptoms between 8 and 36 months in high-risk siblings (HR; n = 161) and low-risk controls (LR; n = 71). Longitudinally, LR and
HR-Typical
showed higher developmental level and functioning, and fewer ASD symptoms than
HR-Atypical
and
HR-ASD
. At 8 months, machine learning classified
HR-ASD
at chance level, and broader atypical development with 69.2% Area Under the Curve (AUC). At 14 months, ASD and broader atypical development were classified with approximately 71% AUC. Thus, prediction of ASD was only possible with moderate accuracy at 14 months.
Abstract
We measure the evolution of the X-ray luminosity-temperature (L
X − T) relation since z ∼ 1.5 using a sample of 211 serendipitously detected galaxy clusters with spectroscopic redshifts ...drawn from the XMM Cluster Survey first data release (XCS-DR1). This is the first study spanning this redshift range using a single, large, homogeneous cluster sample. Using an orthogonal regression technique, we find no evidence for evolution in the slope or intrinsic scatter of the relation since z ∼ 1.5, finding both to be consistent with previous measurements at z ∼ 0.1. However, the normalization is seen to evolve negatively with respect to the self-similar expectation: we find E
−1(z) L
X = 1044.67 ± 0.09(T/5)3.04 ± 0.16(1 + z)−1.5 ± 0.5, which is within 2σ of the zero evolution case. We see milder, but still negative, evolution with respect to self-similar when using a bisector regression technique. We compare our results to numerical simulations, where we fit simulated cluster samples using the same methods used on the XCS data. Our data favour models in which the majority of the excess entropy required to explain the slope of the L
X − T relation is injected at high redshift. Simulations in which active galactic nucleus feedback is implemented using prescriptions from current semi-analytic galaxy formation models predict the positive evolution of the normalization, and differ from our data at more than 5σ. This suggests that more efficient feedback at high redshift may be needed in these models.
Autism spectrum disorder (ASD) is a common, highly heritable, developmental disorder and later‐born siblings of diagnosed children are at higher risk of developing ASD than the general population. ...Although the emergence of behavioural symptoms of ASD in toddlerhood is well characterized, far less is known about development during the first months of life of infants at familial risk. In a prospective longitudinal study of infants at familial risk followed to 36 months, we measured functional near‐infrared spectroscopy (fNIRS) brain responses to social videos of people (i.e. peek‐a‐boo) compared to non‐social images (vehicles) and human vocalizations compared to non‐vocal sounds. At 4–6 months, infants who went on to develop ASD at 3 years (N = 5) evidenced‐reduced activation to visual social stimuli relative to low‐risk infants (N = 16) across inferior frontal (IFG) and posterior temporal (pSTS‐TPJ) regions of the cortex. Furthermore, these infants also showed reduced activation to vocal sounds and enhanced activation to non‐vocal sounds within left lateralized temporal (aMTG‐STG/pSTS‐TPJ) regions compared with low‐risk infants and high‐risk infants who did not develop ASD (N = 15). The degree of activation to both the visual and auditory stimuli correlated with parent‐reported ASD symptomology in toddlerhood. These preliminary findings are consistent with later atypical social brain responses seen in children and adults with ASD, and highlight the need for further work interrogating atypical processing in early infancy and how it may relate to later social interaction and communication difficulties characteristic of ASD.
This fNIRS study demonstrates that at 4–6 months, infants who went on to ASD at 3 years had altered activation to visual and auditory social stimuli, compared to low risk infants, across inferior frontal (IFG) and temporal (aMTG‐STG and pSTS‐TPJ) cortical regions. Cortical responses in infancy correlated with parent‐reported ASD symptomology in toddlerhood. Results demonstrate an early departure from typical development of brain function in individuals who later receive a diagnosis of ASD.
Million degree gas is present at near-zero redshift and is due to either a gaseous Galactic halo or a more diffuse but very massive Local Group medium. We can discriminate between these models ...because the column densities should depend on location in the sky, either relative to the Galaxy bulge or to the M31-Milky Way axis. To search for these signatures, we measured the O VII Ka absorption-line strength toward 25 bright active galactic nuclei (AGNs), plus LMC X-3, using XMM-Newton RGS archival data. The data are in conflict with a purely Local Group model, but support the Galactic halo model. The strongest correlation is between the O VII equivalent widths and the ROSAT background emission measurement in the R45 band (0.4-1 keV), for which O VII emission makes the largest single contribution. This suggests that much of the O VII emission and absorption are cospatial, from which the radius of a uniform halo appears to lie the range 15-110 kpc. The present data do not constrain the type of halo gas model, and an equally good fit is obtained in a model where the gas density decreases as a power law, such as unk super(-8)/ super(2). For a uniform halo with a radius of 20 kpc, the electron density would be 9 x 10 super(-4) cm super(-3), and the gas mass is 4 x 10 super(8) M unk. The redshift of the four highest signal-to-noise ratio (S/N) O VII measurements is consistent with a Milky Way origin rather than a Local Group onigin.
This paper presents both the result of a search for fossil systems (FSs) within the XMM Cluster Survey and the Sloan Digital Sky Survey and the results of a study of the stellar mass assembly and ...stellar populations of their fossil galaxies. In total, 17 groups and clusters are identified at z < 0.25 with large magnitude gaps between the first and fourth brightest galaxies. All the information necessary to classify these systems as fossils is provided. For both groups and clusters, the total and fractional luminosity of the brightest galaxy is positively correlated with the magnitude gap. The brightest galaxies in FSs (called fossil galaxies) have stellar populations and star formation histories which are similar to normal brightest cluster galaxies (BCGs). However, at fixed group/cluster mass, the stellar masses of the fossil galaxies are larger compared to normal BCGs, a fact that holds true over a wide range of group/cluster masses. Moreover, the fossil galaxies are found to contain a significant fraction of the total optical luminosity of the group/cluster within 0.5 R sub(200), as much as 85%, compared to the non-fossils, which can have as little as 10%. Our results suggest that FSs formed early and in the highest density regions of the universe and that fossil galaxies represent the end products of galaxy mergers in groups and clusters.
To investigate temperament as an early risk marker for autism spectrum disorder (ASD), we examined parent-reported temperament for high-risk (HR, n = 170) and low-risk (LR, n = 77) siblings at 8, 14, ...and 24 months. Diagnostic assessment was performed at 36 months. Group-based analyses showed linear risk gradients, with more atypical temperament for HR-ASD, followed by HR-Atypical, HR-Typical, and LR siblings. Temperament differed significantly between outcome groups (0.03 ≤
η
p
2
≤ 0.34). Machine learning analyses showed that, at an individual level, HR-ASD siblings could not be identified accurately, whereas HR infants without ASD could. Our results emphasize the discrepancy between group-based and individual-based predictions and suggest that while temperament does not facilitate early identification of ASD individually, it may help identify HR infants who do not develop ASD.
PDF
