A new tool for validating theoretically derived anisotropic displacement parameters with experiment: directionality of prolate displacement ellipsoids

How well do anisotropic displacement parameters from theory match experiment? The orientation of prolate ellipsoids contributes to the answer!

Search for Subsolar-Mass Ultracompact Binaries in Advanced LIGO's First Observing Run

We present the first Advanced LIGO and Advanced Virgo search for ultracompact binary systems with component masses between 0.2  M_{⊙}-1.0  M_{⊙} using data taken between September 12, 2015 and January 19, 2016. We find no viable gravitational wave candidates. Our null result constrains the coalescence rate of monochromatic (delta function) distributions of nonspinning (0.2  M_{⊙}, 0.2  M_{⊙}) ultracompact binaries to be less than 1.0×10^{6}  Gpc^{-3}  yr^{-1} and the coalescence rate of a similar distribution of (1.0  M_{⊙}, 1.0  M_{⊙}) ultracompact binaries to be less than 1.9×10^{4}  Gpc^{-3}  yr^{-1} (at 90% confidence). Neither black holes nor neutron stars are expected to form below ∼1  M_{⊙} through conventional stellar evolution, though it has been proposed that similarly low mass black holes could be formed primordially through density fluctuations in the early Universe and contribute to the dark matter density. The interpretation of our constraints in the primordial black hole dark matter paradigm is highly model dependent; however, under a particular primordial black hole binary formation scenario we constrain monochromatic primordial black hole populations of 0.2  M_{⊙} to be less than 33% of the total dark matter density and monochromatic populations of 1.0  M_{⊙} to be less than 5% of the dark matter density. The latter strengthens the presently placed bounds from microlensing surveys of massive compact halo objects (MACHOs) provided by the MACHO and EROS Collaborations.

GW170817: Measurements of Neutron Star Radii and Equation of State

On 17 August 2017, the LIGO and Virgo observatories made the first direct detection of gravitational waves from the coalescence of a neutron star binary system. The detection of this gravitational-wave signal, GW170817, offers a novel opportunity to directly probe the properties of matter at the extreme conditions found in the interior of these stars. The initial, minimal-assumption analysis of the LIGO and Virgo data placed constraints on the tidal effects of the coalescing bodies, which were then translated to constraints on neutron star radii. Here, we expand upon previous analyses by working under the hypothesis that both bodies were neutron stars that are described by the same equation of state and have spins within the range observed in Galactic binary neutron stars. Our analysis employs two methods: the use of equation-of-state-insensitive relations between various macroscopic properties of the neutron stars and the use of an efficient parametrization of the defining function p(ρ) of the equation of state itself. From the LIGO and Virgo data alone and the first method, we measure the two neutron star radii as R_{1}=10.8_{-1.7}^{+2.0}  km for the heavier star and R_{2}=10.7_{-1.5}^{+2.1}  km for the lighter star at the 90% credible level. If we additionally require that the equation of state supports neutron stars with masses larger than 1.97  M_{⊙} as required from electromagnetic observations and employ the equation-of-state parametrization, we further constrain R_{1}=11.9_{-1.4}^{+1.4}  km and R_{2}=11.9_{-1.4}^{+1.4}  km at the 90% credible level. Finally, we obtain constraints on p(ρ) at supranuclear densities, with pressure at twice nuclear saturation density measured at 3.5_{-1.7}^{+2.7}×10^{34}  dyn cm^{-2} at the 90% level.

A STAT4 variant increases liver fibrosis risk in Caucasian patients with chronic hepatitis B

BACKGROUND

Host genetic modifiers of the natural history of chronic hepatitis B (CHB) remain poorly understood. Recently, a genome-wide association study (GWAS)-identified polymorphism in the STAT4 gene that contributes to the risk for hepatocellular carcinoma (HCC) was shown to be associated with the full spectrum of hepatitis B virus (HBV) outcomes in Asian patients. However, the functional mechanisms for this effect are unknown and the role of the variant in modulating HBV disease in Caucasians has not been investigated.

AIMS

To determine whether STAT4 genetic variation is associated with liver injury in Caucasian patients with CHB and to investigate potential mechanisms mediating this effect.

METHODS

STAT4 rs7574865 was genotyped in 1085 subjects (830 with CHB and 255 healthy controls). STAT4 expression in liver, PBMCs and NK cells, STAT4 phosphorylation and secretion of interferon-gamma (IFN-γ) according to STAT4 genetic variation was examined.

RESULTS

STAT4 rs7574865 genotype was independently associated with hepatic inflammation (OR: 1.42, 95% CI: 1.07-2.06, P = 0.02) and advanced fibrosis (OR: 1.83, 95% CI: 1.19-2.83, P = 0.006). The minor allele frequency of rs7574865 was significantly lower than that in healthy controls. rs7574865 GG risk carriers expressed lower levels of STAT4 in liver, PBMCs and in NK cells, while NK cells from patients with the risk genotype had impaired STAT4 phosphorylation following stimulation with IL-12/IL-18 and a reduction in secretion of IFN-γ.

CONCLUSION

Genetic susceptibility to HBV persistence, hepatic inflammation and fibrosis in Caucasians associates with STAT4 rs7574865 variant. Downstream effects on NK cell function through STAT4 phosphorylation-dependent IFN-γ production likely contribute to these effects.

Are adverse outcome rates higher in multiple sclerosis patients after total hip arthroplasty?

Aims

This study compared multiple sclerosis (MS) patients who underwent primary total hip arthroplasty (THA) with a matched cohort. Specifically, we evaluated: 1) implant survivorship; 2) functional outcomes (modified Harris Hip Scores (mHHS), Hip Disability and Osteoarthritis Outcome Score, Joint Replacement (HOOS JR), and modified Multiple Sclerosis Impact Scale (mMSIS) scores (with the MS cohort also evaluated based on the disease phenotype)); 3) physical therapy duration and return to function; 4) radiographic outcomes; and 5) complications.

Patients and Methods

We reviewed our institution's database to identify MS patients who underwent THA between January 2008 and June 2016. A total of 34 MS patients (41 hips) were matched in a 1:2 ratio to a cohort of THA patients who did not have MS, based on age, body mass index (BMI), and Charlson/Deyo score. Patient records were reviewed for complications, and their functional outcomes and radiographs were reviewed at their most recent follow-up.

Results

Compared with the matched cohort, MS patients had lower all-cause implant survivorship at eight years (91.5% (95% confidence interval (CI) 82.7 to 100) vs 98.7% (95% CI 96.2 to 100)) (p = 0.033), lower mHHS scores (66 vs 80, p < 0.001), and HOOS JR scores (79 vs 88, p = 0.009). Multiple sclerosis patients also required more physiotherapy (five weeks vs three weeks, p = 0.002) and took longer to return to baseline (seven weeks vs five weeks, p = 0.010) than the matched cohort. Furthermore, MS patients had more complications than the non-MS patients (six vs zero, p < 0.001). The worse outcomes of the MS group can potentially be explained by predisposition of these patients to mechanical complications and progression of their disease during the period of this study, as demonstrated by worsening of the mMSIS scores (2.9 vs 3.4; p = 0.008).

Conclusion

MS patients had lower implant survivorship, lower functional outcome scores, and increased complication rates; in addition, MS patients took longer to return to their baseline functional level after THA. Cite this article: Bone Joint J 2018;100-B:875-81.

Search for Tensor, Vector, and Scalar Polarizations in the Stochastic Gravitational-Wave Background

The detection of gravitational waves with Advanced LIGO and Advanced Virgo has enabled novel tests of general relativity, including direct study of the polarization of gravitational waves. While general relativity allows for only two tensor gravitational-wave polarizations, general metric theories can additionally predict two vector and two scalar polarizations. The polarization of gravitational waves is encoded in the spectral shape of the stochastic gravitational-wave background, formed by the superposition of cosmological and individually unresolved astrophysical sources. Using data recorded by Advanced LIGO during its first observing run, we search for a stochastic background of generically polarized gravitational waves. We find no evidence for a background of any polarization, and place the first direct bounds on the contributions of vector and scalar polarizations to the stochastic background. Under log-uniform priors for the energy in each polarization, we limit the energy densities of tensor, vector, and scalar modes at 95% credibility to Ω_{0}^{T}<5.58×10^{-8}, Ω_{0}^{V}<6.35×10^{-8}, and Ω_{0}^{S}<1.08×10^{-7} at a reference frequency f_{0}=25  Hz.

Trends in hepatocellular carcinoma incidence and survival among people with hepatitis C: An international study

This study evaluates trends in hepatitis C virus (HCV)-related hepatocellular carcinoma (HCC) incidence and survival in three settings, prior to introduction of direct-acting antiviral (DAA) therapies. HCV notifications from British Columbia (BC), Canada; New South Wales (NSW), Australia; and Scotland (1995-2011/2012/2013, respectively) were linked to HCC diagnosis data via hospital admissions (2001-2012/2013/2014, respectively) and mortality (1995-2013/2014/2015, respectively). Age-standardized HCC incidence rates were evaluated, associated factors were assessed using Cox regression, and median survival time after HCC diagnosis was calculated. Among 58 487, 84 529 and 31 924 people with HCV in BC, NSW and Scotland, 734 (1.3%), 1045 (1.2%) and 345 (1.1%) had an HCC diagnosis. Since mid-2000s, HCC diagnosis numbers increased in all jurisdictions. Age-standardized HCC incidence rates remained stable in BC and Scotland and increased in NSW. The strongest predictor of HCC diagnosis was older age [birth <1945, aHR in BC 5.74, 95% CI 4.84, 6.82; NSW 9.26, 95% CI 7.93, 10.82; Scotland 12.55, 95% CI 9.19, 17.15]. Median survival after HCC diagnosis remained stable in BC (0.8 years in 2001-2006 and 2007-2011) and NSW (0.9 years in 2001-2006 and 2007-2013) and improved in Scotland (0.7 years in 2001-2006 to 1.5 years in 2007-2014). Across the settings, HCC burden increased, individual-level risk of HCC remained stable or increased, and HCC survival remained extremely low. These findings highlight the minimal impact of HCC prevention and management strategies during the interferon-based HCV treatment era and form the basis for evaluating the impact of DAA therapy in the coming years.

The antiviral role of zinc and metallothioneins in hepatitis C infection

Metallothioneins (MTs) are small, cysteine-rich proteins characterized by a high affinity for monovalent and divalent cations, such as copper and zinc. Of the four known MT isoforms, only, members of the MT 1 and 2 subfamilies are widely expressed, acting as metal chaperones whose primary role is to mediate intracellular zinc homoeostasis. Metallothioneins are potently induced by heavy metals and other sources of oxidative stress where they facilitate metal binding and detoxification as well as free radical scavenging. Metallothionein expression is well documented in the context of viral infection; however, it remains uncertain whether MTs possess specific antiviral roles or whether induction is merely a consequence of cellular stress. To better understand the role of MTs following hepatitis C virus (HCV) infection, we examined MT expression and localization in vitro and in vivo and used a siRNA knockdown approach to ascertain their antiviral efficacy. We confirmed HCV-driven MT induction in vitro and demonstrated MT accumulation in the nucleus of HCV-infected hepatocytes by immunofluorescence. Using a pan-MT siRNA to knock down all members of the MT1 and MT2 subfamilies, we demonstrate that they are mildly antiviral against the JFH1 strain of HCV in vitro (~1.4 fold increase in viral RNA, P < .05). Furthermore, the antiviral effect of zinc treatment against HCV in vitro was mediated through MT induction (P < .05). Our data suggest a potential benefit of using zinc as a low-cost adjunct to current HCV antiviral therapies and suggest that zinc may facilitate the antiviral role of MTs against other viruses.

Prospects for observing and localizing gravitational-wave transients with Advanced LIGO, Advanced Virgo and KAGRA

We present possible observing scenarios for the Advanced LIGO, Advanced Virgo and KAGRA gravitational-wave detectors over the next decade, with the intention of providing information to the astronomy community to facilitate planning for multi-messenger astronomy with gravitational waves. We estimate the sensitivity of the network to transient gravitational-wave signals, and study the capability of the network to determine the sky location of the source. We report our findings for gravitational-wave transients, with particular focus on gravitational-wave signals from the inspiral of binary neutron star systems, which are the most promising targets for multi-messenger astronomy. The ability to localize the sources of the detected signals depends on the geographical distribution of the detectors and their relative sensitivity, and [Formula: see text] credible regions can be as large as thousands of square degrees when only two sensitive detectors are operational. Determining the sky position of a significant fraction of detected signals to areas of 5-[Formula: see text] requires at least three detectors of sensitivity within a factor of [Formula: see text] of each other and with a broad frequency bandwidth. When all detectors, including KAGRA and the third LIGO detector in India, reach design sensitivity, a significant fraction of gravitational-wave signals will be localized to a few square degrees by gravitational-wave observations alone.

Data Resource: the Kent Integrated Dataset (KID)

Introduction

Electronic healthcare records from the UK are accessible to researchers via several platforms, but these platforms typically include data from a limited subset of health and care services. The Kent Integrated Dataset (KID) provides insight into system-wide health and care utilisation for the whole population of Kent and Medway.

Processes

The KID uses pseudonymisation-at-source to link patient-level records from services including general practices, hospitals, community health services and social care. Data is refreshed monthly and processes to monitor data quality have been developed.

Data contents

For each episode of care, the KID includes date of the episode, the type of service accessed, the cost of the episode and clinical information such as the health condition being treated and results of diagnostic tests. The dataset also includes contextual information such as the neighbourhood deprivation.

Conclusions

The KID is a unique and rich dataset available to researchers who are investigating a broad range of public health questions. It provides system-level insight into patient journeys and care utilisation and supports commissioning based on patient needs