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"Mathur, S"
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Observations of the missing baryons in the warm–hot intergalactic medium
It has been known for decades that the observed number of baryons in the local Universe falls about 30–40 per cent short
1
,
2
of the total number of baryons predicted
3
by Big Bang nucleosynthesis, as inferred
4
,
5
from density fluctuations of the cosmic microwave background and seen during the first 2–3 billion years of the Universe in the so-called ‘Lyman α forest’
6
,
7
(a dense series of intervening H
i
Lyman α absorption lines in the optical spectra of background quasars). A theoretical solution to this paradox locates the missing baryons in the hot and tenuous filamentary gas between galaxies, known as the warm–hot intergalactic medium. However, it is difficult to detect them there because the largest by far constituent of this gas—hydrogen—is mostly ionized and therefore almost invisible in far-ultraviolet spectra with typical signal-to-noise ratios
8
,
9
. Indeed, despite large observational efforts, only a few marginal claims of detection have been made so far
2
,
10
. Here we report observations of two absorbers of highly ionized oxygen (O
vii
) in the high-signal-to-noise-ratio X-ray spectrum of a quasar at a redshift higher than 0.4. These absorbers show no variability over a two-year timescale and have no associated cold absorption, making the assumption that they originate from the quasar’s intrinsic outflow or the host galaxy’s interstellar medium implausible. The O
vii
systems lie in regions characterized by large (four times larger than average
11
) galaxy overdensities and their number (down to the sensitivity threshold of our data) agrees well with numerical simulation predictions for the long-sought warm–hot intergalactic medium. We conclude that the missing baryons have been found.
Observations of two absorbers of highly ionized oxygen in the X-ray spectrum of a quasar account for the missing baryons in the Universe.
Journal Article
Toward evidence-based communication on overweight body mass index and mortality
Background
Reducing overweight and obesity has been a longstanding focus of public health messaging and physician–patient interactions. Clinical guidelines by major public health organizations describe both overweight and obesity as risk factors for mortality and other health conditions. Accordingly, a majority of primary care physicians believe that overweight BMI (even without obesity) strongly increases mortality risk.
Main points
The current evidence base suggests that although both obese BMI and underweight BMI are consistently associated with increased all-cause mortality, overweight BMI (without obesity) is not meaningfully associated with increased mortality. In fact, a number of studies suggest modest protective, rather than detrimental, associations of overweight BMI with all-cause mortality. Given this current evidence base, clinical guidelines and physician perceptions substantially overstate all-cause mortality risks associated with the range of BMIs classified as “overweight” but not “obese.” Discrepancies between evidence and communication regarding mortality raise the question of whether similar discrepancies exist for other health outcomes.
Conclusions
Health communication that inaccurately conveys current evidence may do more harm than good; this applies to communication from health authorities to health practitioners as well as to communication from health practitioners to individual patients. We give three recommendations to better align health communication with the current evidence. First, recommendations to the public and health practitioners should distinguish overweight from obese BMI and at this time should not describe overweight BMI as a risk factor for all-cause mortality. Second, primary care physicians’ widespread misconceptions about overweight BMI should be rectified. Third, the evidence basis for other potential risks or benefits of overweight BMI should be rigorously examined and incorporated appropriately into health communication.
Journal Article
Surgical resection for large hepatocellular carcinoma and those beyond BCLC: systematic review with proposed management algorithm
BackgroundHepatocellular carcinoma (HCC) accounts for the sixth most common cancer and ranks third in mortality worldwide with inhomogeneity in terms of resection for advanced-stage disease.MethodsA systematic review of published literature using the PubMed, Medline, and Google Scholar databases from 1995 to 2020 was conducted to identify studies that reported outcomes of resection for solitary HCC > 10 cm, BCLC B/C, and multinodular HCC. Our aim was to assess overall survival for resection, identify poor prognostic factors, and to compare it to trans-arterial chemotherapy (TACE) where data was available.ResultsEighty-nine articles were included after a complete database search in the systematic review as per our predefined criteria. Analysis revealed a 5-year overall survival of 33.5% for resection of HCC > 10 cm, 41.7% for BCLC B, 23.3% for BCLC C, and 36.6% for multinodular HCC. Peri-operative mortality ranged from 0 to 6.9%. Studies comparing resection versus TACE for BCLC B/C had a survival of 40% versus 17%, respectively.ConclusionOur systematic review justifies hepatic resection wherever feasible for hepatocellular carcinomas > 10 cm, BCLC B, BCLC C, and multinodular tumors. In addition, we identified and proposed an algorithm with five poor prognostic criteria in this group of patients who may benefit from adjuvant TACE.
Journal Article
Qualitative Assessment of Geoheritage for Geotourism Promotion: a Case Study from Mehrangarh Ridge in Jodhpur City, Western Rajasthan, India
Mehrangarh ridge (MGR) of Jodhpur, situated in north western part of India, is endowed with wide variety of Georesource of volcanic rocks of Malani Igneous Suite (MIS) of Cryogenian age and overlying Jodhpur Group (JG) of Ediacaran age belonging to Marwar Supergroup (MSG). MIS is the third largest, felsic, anorogenic, and terrestrial volcanic province of the world that witnessed Pan African orogeny related to the splitting of Rodinia Supercontinent. Unique and rare volcanic features of MIS at MGR have been declared as the National Geological Monuments of India with its interface with JG. The suite of fluvio-deltaic to coastal sediments of JG at MGR preserved text book style sedimentary structures with rich assemblage of oldest and complex Ediacaran fossils. MIS and JG altogether at MGR constitute the strato-type sections and outdoor geological museums in India that display geological processes of about 200 million years of Earth’s history. Such records of past tectonics, climates, and environments characterize the land-sea interaction and distribution in this part of Eastern Gondwana land that represent global geodiversity and provide eminent narratives for geo-education. However, these relict volcanic and sedimentary Georesources though formed site-specific landforms of MGR but have received less attention towards their geoheritage values. MGR is also endowed with many archaeological heritage monuments (HM) with additional cultural values that are constructed by indigenous Heritage Stone Resources (HSR) of JG. The HM represents old patronage of Jodhpur since medieval time that makes it a famous tourist destination of the world. In absence of geotourism applications and infrastructures in India, efforts are made under present study to provide suitable qualitative methodologies to identify geosites and assess geoheritage of educational and geotourism values taking MGR as a case study. Based on the proposed methodologies, we propose twelve geosites of geological, geomorphological, and archaeological types of geoheritage at MGR. These significant geosites of the Cryogenian—Ediacaran successions should be conserved as important geoheritage sites for geotourism through the proposed Geopark at MGR in Jodhpur.
Journal Article
Fundus autofluorescence features specific for EYS-associated retinitis pigmentosa
To assess the utility of fundus autofluorescence (FAF) patterns for predicting the EYS genotype in retinitis pigmentosa (RP) patients.
This retrospective, multi-institutional study analyzed FAF images from 200 RP patients (74 with EYS and 126 without EYS) from Singapore and Japan. Seven FAF patterns including the infinity sign and a broad banded hyper-autofluorescent leading edge were evaluated for their association with the EYS genotype.
The infinity sign and broad banded hyperautofluorescent leading edge occurred more frequently in EYS eyes (p = 0.0014 and p = 0.036 respectively). Logistic regression analysis showed that the infinity sign was predictive of EYS (p = 0.003). The combined FAF parameters predicted EYS with a specificity of 95.20%, sensitivity of 25.68% and accuracy of 69.50%, with a cut-off value 0.5 based on the probability of seven FAF parameters.
In this multinational cohort study of patients with RP, we demonstrated that specific FAF patterns, particularly the infinity sign, have clinical utility in identifying patients with EYS-associated disease. These findings may be useful for clinicians and geneticists when genotyping patients with RP, and may also enhance our understanding of underlying pathophysiology of EYS-associated RP, which is a prevalent cause of RP in Asia and elsewhere.
Journal Article
X-Ray Detection of the Galaxy’s Missing Baryons in the Circumgalactic Medium of L Galaxies
The number of baryons hosted in the disks of galaxies is lower than expected based on the mass of their dark matter halos and the fraction of baryon-to-total matter in the Universe, giving rise to the so-called galaxy missing-baryon problem. The presence of cool circumgalactic matter gravitationally bound to its galaxy’s halo up to distances of at least 10 times the size of the galaxy’s disk mitigates the problem but is far from being sufficient for its solution. It has instead been suggested that the galaxy’s missing baryons may hide in a much hotter gaseous phase of the circumgalactic medium, possibly near the halo virial temperature and coexisting with the cool phase. Here we exploit the best available X-ray spectra of known cool circumgalactic absorbers of L* galaxies to report the first direct high statistical significance (best estimates ranging from 4.2σ to 5.6σ, depending on fitting methodology) detection of associated O vii absorption in the stacked XMM-Newton and Chandra spectra of three quasars. We show that these absorbers trace the hot medium in the X-ray halo of these systems at logT(in K) ≃ 5.8–6.3 (comprising the halo virial temperature T vir ≃ 106 K). We estimate masses of the X-ray halo within one virial radius within the interval Mhot−CGM≃(1–1.7)×1011(Z/0.3Z⊙)−1 M ⊙. For these systems, this corresponds to galaxy missing-baryon fractions in the range ξb=Mhot−CGM/Mmissing≃(0.7–1.2)(Z/0.3Z⊙)−1 , thus potentially closing the galaxy baryon census in typical L* galaxies. Our measurements contribute significantly to the solution of the long-standing galaxy missing-baryon problem and to the understanding of the continuous cycle of baryons in-and-out of galaxies throughout the life of the Universe.
Journal Article
Treatment of textile effluent by electrocoagulation in a novel reactor to mitigate environmental pollution
Remediation of textile wastewater with conventional technologies is challenging as it contains a significant amount of unfixed dyes in addition to various biodegradable and non-biodegradable chemicals. The present work aims at treating simulated textile wastewater in batch mode through Electro-coagulation by employing a novel perforated three-dimensional rotating aluminum electrode. This electrode aids in avoiding common issues associated with standard plate electrode systems. The combined effect of operating parameters on efficiency was examined using the Taguchi method. The experiments were also conducted on real textile effluents at optimum conditions identified for the simulated textile wastewater. At operating conditions of initial pH 6, electrolyte(sodium chloride) concentration of 3 g/L, current density of 20 mA/cm
2
, rotational speed of 50 rpm and electrolysis time of 40 min, the color and Chemical oxygen demand removal efficiency for simulated textile wastewater of 99.99% and 85.63% were observed at Specific Electrical Energy Consumption of 0.191 J/mg of the Chemical oxygen demand removed and for real textile effluent, color and Chemical oxygen demand removal efficiencies of 92–98% and 80–85% respectively were observed for Specific Electrical Energy Consumption ranging between 0.025–0.031 J/mg. On comparing with the literature, it was observed that the energy consumption of three-dimensional rotating electrode for similar removal efficiency is much lower than plate electrodes.
Journal Article
Andexanet Alfa for the Reversal of Factor Xa Inhibitor Activity
The new oral anticoagulants have many advantages over warfarin, but one disadvantage is the inability to rapidly reverse their anticoagulant effects. Andexanet, a small-molecule factor Xa fragment, rapidly lowered levels of rivaroxaban and apixaban in older healthy volunteers.
The direct factor Xa inhibitors apixaban, rivaroxaban, and edoxaban are used in the prevention and treatment of thromboembolism. Indications for the use of these agents include the prevention of stroke in patients with nonvalvular atrial fibrillation, the treatment and secondary prevention of deep-vein thrombosis and pulmonary embolism, and the prevention of venous thrombosis after orthopedic surgery. In spite of the demonstrated safety and efficacy of factor Xa inhibitors, as well as their practical advantages over vitamin K antagonists such as warfarin, the lack of a specific antidote to reverse their anticoagulant effects is an important limitation. In clinical trials involving . . .
Journal Article
TCF-1 and HEB cooperate to establish the epigenetic and transcription profiles of CD4+CD8+ thymocytes
Thymocyte development requires a complex orchestration of multiple transcription factors. Ablating either TCF-1 or HEB in CD4
+
CD8
+
thymocytes elicits similar developmental outcomes including increased proliferation, decreased survival, and fewer late
Tcra
rearrangements. Here, we provide a mechanistic explanation for these similarities by showing that TCF-1 and HEB share ~7,000 DNA-binding sites genome wide and promote chromatin accessibility. The binding of both TCF-1 and HEB was required at these shared sites for epigenetic and transcriptional gene regulation. Binding of TCF-1 and HEB to their conserved motifs in the enhancer regions of genes associated with T cell differentiation promoted their expression. Binding to sites lacking conserved motifs in the promoter regions of cell-cycle-associated genes limited proliferation. TCF-1 displaced nucleosomes, allowing for chromatin accessibility. Importantly, TCF-1 inhibited Notch signaling and consequently protected HEB from Notch-mediated proteasomal degradation. Thus, TCF-1 shifts nucleosomes and safeguards HEB, thereby enabling their cooperation in establishing the epigenetic and transcription profiles of CD4
+
CD8
+
thymocytes.
Thymocyte development requires a complex orchestration of multiple transcription factors. Gournari and colleagues find that Tcf-1 and HEB cooperate to establish the epigenetic and transcription profiles of CD4
+
CD8
+
thymocytes
Journal Article