bluuebunny/crossref_metadata_2025 huggingface dataset:
An optical coherence photoacoustic microscopy system using a fiber optic sensor
Authors: Deng Shiyu , Haindl Richard , Zhang Edward , Beard Paul , Scheuringer Eva , Sturtzel Caterina , Li Qian , Deloria Abigail J. , Sattmann Harald , Leitgeb Rainer A. , Yuan Yi , Schmetterer Leopold , Pramanik Manojit , Distel Martin , Drexler Wolfgang , Liu Mengyang
Published: September 2021

In this work, a novel fiber optic sensor based on Fabry–Pérot interferometry is adopted in an optical coherence photoacoustic microscopy (OC-PAM) system to enable high-resolution in vivo imaging. The complete OC-PAM system is characterized using the fiber optic sensor for photoacoustic measurement. After characterization, the performance of the system is evaluated by imaging zebrafish larvae in vivo. With a lateral resolution of 3.4 μm and an axial resolution of 3.7 μm in air, the optical coherence microscopy subsystem visualizes the anatomy of the zebrafish larvae. The photoacoustic microscopy subsystem reveals the vasculature of the zebrafish larvae with a lateral resolution of 1.9 μm and an axial resolution of 37.3 μm. As the two modalities share the same sample arm, we obtain inherently co-registered morphological and vascular images. This OC-PAM system provides comprehensive information on the anatomy and vasculature of the zebrafish larvae. Featuring compactness, broad detection bandwidth, and wide detection angle, the fiber optic sensor enables a large field of view with a static sensor position. We verified the feasibility of the fiber optic sensor for dual-modality in vivo imaging. The OC-PAM system, as a non-invasive imaging method, demonstrates its superiority in the investigation of zebrafish larvae, an animal model with increasing significance in developmental biology and disease research. This technique can also be applied for functional as well as longitudinal studies in the future.
Pure-quartic solitons and their generalizations—Theory and experiments
Authors: de Sterke C. Martijn , Runge Antoine F. J. , Hudson Darren D. , Blanco-Redondo Andrea
Published: September 2021

Solitons are wave packets that can propagate without changing shape by balancing nonlinear effects with the effects of dispersion. In photonics, they have underpinned numerous applications, ranging from telecommunications and spectroscopy to ultrashort pulse generation. Although traditionally the dominant dispersion type has been quadratic dispersion, experimental and theoretical research in recent years has shown that high-order, even dispersion enriches the phenomenon and may lead to novel applications. In this Tutorial, which is aimed both at soliton novices and at experienced researchers, we review the exciting developments in this burgeoning area, which includes pure-quartic solitons and their generalizations. We include theory, numerics, and experimental results, covering both fundamental aspects and applications. The theory covers the relevant equations and the intuition to make sense of the results. We discuss experiments in silicon photonic crystal waveguides and in a fiber laser and assess the promises in additional platforms. We hope that this Tutorial will encourage our colleagues to join in the investigation of this exciting and promising field.
Stress analysis and lifetime prediction for Ti–6Al–4V welding joint under fatigue loading
Authors: Liu Yang , Xia Shangzhou , Song Jianan , Qi Hongyu , Li Shaolin , Yang Xiaoguang , Shi Duoqi
Published: September 2021

A welded joint has a complex gradient microstructure. The effects of local deformation in the fusion zone, heat-affected zone (HAZ), and other areas, on the macroscopic fatigue properties of an inhomogeneous welded joint, are not fully understood. Thus, it is necessary to correlate the microstructural features and their related local deformation mechanisms with macroscopic fatigue properties. In this study, cyclic stress–strain curves and lifetime model parameters of materials in different HAZs were determined by hardness distribution and base–metal material properties. A user element subroutine was developed in the elastic–plastic finite element analysis to obtain the local stress and strain in the joint. ‘Danger points’ were selected to predict fatigue lifetime with the Manson–Coffin damage equation. The prediction results agreed closely with experimental observations within the low-cycle fatigue lifetime regime.

Highlights

A new LCF life analysis method, for coated specimens, was developed based on the fracture mechanics. Life prediction method for coated specimens was proposed and verified by LCF tests. Coating-induced lifetime degradation was analysed quantitatively at different temperatures. Effects of stress amplitude on the surface crack initiation were investigated.
Reinforcement learning-enhanced protocols for coherent population-transfer in three-level quantum systems
Authors: Brown Jonathon , Sgroi Sofia , Giannelli Luigi , Paraoanu Gheorghe Sorin , Paladino Elisabetta , Falci Giuseppe , Paternostro Mauro , Ferraro Alessandro
Published: September 2021

We deploy a combination of reinforcement learning-based approaches and more traditional optimization techniques to identify optimal protocols for population transfer in a multi-level system. We constrain our strategy to the case of fixed coupling rates but time-varying detunings, a situation that would simplify considerably the implementation of population transfer in relevant experimental platforms, such as semiconducting and superconducting ones. Our approach is able to explore the space of possible control protocols to reveal the existence of efficient protocols that, remarkably, differ from (and can be superior to) standard Raman, stimulated Raman adiabatic passage or other adiabatic schemes. The new protocols that we identify are robust against both energy losses and dephasing.
Semi-inclusive lepto-production of hidden-charm exotic hadrons *
Authors: Yang Zhi , Guo Feng-Kun
Published: September 2021

We investigate the semi-inclusive production of hidden-charm exotic states, including the

,

,

and pentaquark

states, in lepton-proton scattering processes. These hadrons are close to the thresholds of a pair of charm and anticharm hadrons and are assumed to possess a hadronic molecular structure as their main feature. To provide order-of-magnitude estimates of the cross sections, we use Pythia to simulate the short-distance productions of the constituent hadrons, which then rescatter to form exotic hadrons. The estimates for the

and

states are not in conflict with the upper limits measured in the COMPASS experiment for the exclusive photoproduction process. The results indicate that the considered hidden-charm states can be copiously produced at the proposed electron-ion colliders EicC and US-EIC.
Monitoring of optical properties of deep lake water
Authors: Ryabov E. , Tarashansky B.
Published: September 2021

We present the results of the one year monitoring of absorption and scattering lengths of light with wavelengths in the range of 375 nm to 532 nm within the effective volume of the deep underwater neutrino telescope Baikal-GVD, which were measured by a device
named ≪BAIKAL-5D≫. ≪BAIKAL-5D≫ was installed during the 2020 winter expedition at a depth of 1250 m. To carry out the optical measurements, we use a device with a shaded point-like isotropic light source having a spectral resolution of about 3 nm. A wide angle light receiver is moved by a stepper motor so that the distance between the receiver and the light source can vary from 0.9 m to 7.4 m. The absorption and scattering lengths were measured every week in 6 spectral points. The short-time variation of absorption length was estimated.
Experience in application of modern technologies of measuring the structure of currents in the upstream waters of large hydroelectric complexes (on the example of the Kama HPP)
Authors: Ljahin U S , Bogomolov A V , Lepihin A P
Published: September 2021

The creation of reservoirs on watercourses leads to significant changes in the hydrological regime of water bodies: it allows to smooth out the peaks of maximum water discharge during the flood period and to regulate low runoff. The reservoirs with a significant storage capacity enable to solve a wide range of water management problems, among which are: using the falling water energy for hydropower purposes, ensuring uninterrupted water supply and navigation. In view of the fact that dams are generally managed by hydropower companies, the regime for regulating downstream water mass discharges is often determined by the schedule of daily electricity consumption. Intraday changes in the volume of water discharge through the hydroelectric units of hydroelectric power plants form multidirectional flows in the upstream, which can affect the work of other water users. This paper examines the impact of intraday changes in flow rates of downstream water discharges on the dynamic and physical properties of the water mass in the area of the drinking water intake heads of the city of Perm.
A three-dimensional thermohydrodynamic model for Krasnoyarsk Reservoir
Authors: Zinoviev A T , Koshelev K B , Marusin K V
Published: September 2021

The paper presents a 3D model for a deep flowing water body based on the open software package Delft3D to describe and predict thermohydrodynamic (THD) processes in existing and projected reservoirs of Siberia. As an example, a 3D model for non-stationary THD processes of the Krasnoyarsk Reservoir was built and tested. For its construction, we developed a Digital Relief Model (DRM) for the Krasnoyarsk Reservoir basin, generated a finite-difference grid, identified the empirical constants and formulated the initial and boundary conditions. Numerical simulation of current velocity and water temperature of the reservoir for spring/summer of the scenario year was performed.
Climate change impact on the inflow to the reservoirs of the Moscow water supply system
Authors: Korobkina E , Filippova I
Published: September 2021

The dynamics of long-term fluctuations in the inflow to the reservoirs of the Moscow water supply system for different time intervals is analysed. The article deals with part of the Moscow drinking water supply system, namely Moskvoretskaya Water System and Vazuza Hydrotechnical System (MVHS). A significant change in the parameters of the inflow distribution is shown. It is concluded that it is necessary to clarify the rules for the operation of reservoirs system under conditions of hydrological regime changes.
Calculation of the maximum levels of lakes in the north-west Russia in the absence of hydrometric observation data
Authors: Davydenko E V , Sikan A V
Published: September 2021

The methodology for calculation the maximum water levels of unexplored lakes is examined in the article. This methodology is based on the generalization of all available information about the lakes’ regime in the North-West of the Russian Federation. The dependence of the standard deviation of the upper water level on the average long-term upper level is revealed for medium and small lakes with a specific drainage area of less than 100. The recommendations for calculation of the parameters of the probability curve of maximum levels of unexplored lakes of the North-West of Russia and of the Southern part of the Kola Peninsula are developed. It is proposed to determine the probability curve of maximum water levels of an unexplored lake not with accordance to the similar water tank, but on the basis of regional generalizations, which integrates all available information about the lake regime of the studied area.
Preliminary patterns of the formation abrasion-accumulative jumpers in the bays entrance gates of the lake area of the Volgograd Reservoir
Authors: Baranova M S , Kochetkova A I , Bryzgalina E S , Ob“edkova O A , Leont‘ev D A
Published: September 2021

The article contents preliminary process patterns. They were obtained as a result of a researching of some representative bays of the Volgograd reservoir in 2019-2020, as well as an analysis of archival materials, maps and satellite images. The bays separation process depends on the primary volume, morphological features, lithological composition of the coasts, the speed and direction of wave, the frequency and repeatability of storms, and the anthropogenic factor. There are some differences in the formation of the abrasion-accumulative jumpers on the right and left coasts of the reservoir. It was previously established that current’s speeds formative jumpers are 0.48-0.62, 0.63-0.78, 2.83-2.89, 3.60-3.64 m/s. The spatiotemporal dynamics of the formation and development of bays estuarine abrasion-accumulative jumpers of the Volgograd reservoir was revealed by our researching.
Water bodies on the surface of the earth (reservoirs and lakes) and their influence on the long-term changes in the regulated rivers’ runoff. A comparative study
Authors: Dobrovolski S G , Istomina M N , Lebedeva I P , Sokolova O V , Solomonova I V , Yu Vyruchalkina T
Published: September 2021

Archives of data on the most important reservoirs and flowing lakes of the world, and on long-term changes in the flow of rivers regulated by them have been formed. The features of the parameters of artificially regulated rivers and lacustrine rivers and the dependence of these parameters on the characteristics of reservoirs and lakes were analysed. A phenomenon of «monotonous» and «intermittent» nonstationarity are described. The possible role of reservoirs and lakes in their formation has been assessed.
Sedimentation in the Volga Cascade reservoirs in the 21st century
Authors: Zakonnov V V
Published: September 2021

The complex surveys of sediments in the Volga River reservoir has begun in the 20th century and continued in the 21st century providing the basis for a modern quantitative assessment of the impact of bottom sediments on functioning of freshwater ecosystems. The results may be used in modelling of the multi-factor components in the water-bottom sediments-biota system, prediction, creating of object-oriented, special and thematic maps as well as for making decisions on elimination the negative consequences associated with water quality.
Modelling the response of the Ivankovo Reservoir ecosystem to changes in the external chemical load
Authors: Datsenko Y S , Puklakov V V
Published: September 2021

A two-dimensional hydroecological model is used to analyse changes in water quality indicators in the Ivankovo Reservoir due to the response of the reservoir to the doubling of their concentrations in the main tributaries of the reservoir set in the model in the average water content year.
Features of the impact of thermal power plants on the environment on the example of the Uy River Basin
Authors: Vtorova A I , Myakisheva N V
Published: September 2021

The probabilistic analysis of intra-annual and interannual variability of river flow in the Uy river basin is carried out using the theory of random processes. The results of the analysis are summarized in terms of a probabilistic model. The regulatory capacity of the catchment area and man-made structures is estimated. Materials of observations made it possible to assess the hydrological structure of flowing water bodies and the impact of waste water from thermal power plants. Analysis of the hydrological and hydrochemical regime of reservoirs has shown that dynamic mixing plays a significant role in the regime of water bodies.
Application of artificial neural networks in solving water management problems
Authors: Venitsianov E V , Skonechnii M N
Published: September 2021

Overview of the main directions of using artificial neural networks for water monitoring and quality problems: optimization of monitoring networks, modelling of the state of aquatic ecosystems and diffuse pollution. Conclusions about the prospects and functional capabilities of artificial neural networks in solving water management problems.
Calculation of the radiated power in WEST
Authors: Devynck P , Fedorczak N , Mao R , Vartanian S
Published: September 2021

The WEST tokamak is currently equipped with a set of horizontal bolometers to estimate the radiation level of plasma scenarios. The exact relation between bolometer signal and radiating power is derived, highlighting the approximations required to express a proportionality between bolometer signal and radiation level. Further approximations are needed to correct for overlapping lines of sights. They are done via a truncated trapeze approximation. To test the robustness of all these approximations and uncertainties, a synthetic diagnostic basis is constructed coupled to a Monte Carlo ray-tracing tool, and applied to a large set of emissivity phantoms representative of WEST plasma geometries and radiation distributions. It results that the approximations are valid, with uncertainty levels bounded by 5% to 10% depending on the plasma geometry. Application to WEST plasmas shows that the radiated power fraction (related to total power) is about 50% in the first experimental campaigns. A finite radiation level originates from the divertor together with finite radiations from the core. It suggests a detrimental mixture of light impurities and tungsten in the plasma, possibly caused by poor chamber conditioning.
Sequential Projected Newton method for regularization of nonlinear least squares problems
Authors: Cornelis J , Vanroose W
Published: September 2021

We develop a computationally efficient algorithm for the automatic regularization of nonlinear inverse problems based on the discrepancy principle. We formulate the problem as an equality constrained optimization problem, where the constraint is given by a least squares data fidelity term and expresses the discrepancy principle. The objective function is a convex regularization function that incorporates some prior knowledge, such as the total variation regularization function. Using the Jacobian matrix of the nonlinear forward model, we consider a sequence of quadratically constrained optimization problems that can all be solved using the Projected Newton method. We show that the solution of such a quadratically constrained sub-problem results in a descent direction for an exact merit function. This merit function can then be used to describe a formal line-search method. We also formulate a slightly more heuristic approach that simplifies the algorithm and allows for an inexact solution of the sequence of sub-problems. We illustrate the behavior of the algorithm using a number of numerical experiments, with Talbot-Lau x-ray phase contrast imaging as the main application. The numerical experiments confirm that the quadratically constrained sub-problems need not be solved with high accuracy in early iterations to make sufficient progress towards the solution. In addition, we show that the proposed method is able to produce reconstructions of similar quality compared to other state-of-the-art approaches with a significant reduction in computational time.
The prime spectrum of an automorphism group of an 𝐴𝑇4(𝑝,𝑝+2,𝑟)-graph
Authors: Tsiovkina L.
Published: September 2021

The present paper is devoted classification of

A
T
4

(
p
,
p
+
2
,
r
)

\mathrm {AT4}(p,p+2,r)

-graphs. There is a unique

A
T
4

(
p
,
p
+
2
,
r
)

\mathrm {AT4}(p,p+2,r)

-graph with

p
=
2

p=2

, namely, the distance-transitive Soicher graph with intersection array

{
56
,
45
,
16
,
1
;
1
,
8
,
45
,
56
}

\{56, 45, 16, 1;1, 8, 45, 56\}

, whose local graphs are isomorphic to the Gewirtz graph. The existence of an

A
T
4

(
p
,
p
+
2
,
r
)

\mathrm {AT4}(p,p+2,r)

-graph with

p
>
2

{p>2}

remains an open question. It is known that the local graphs of each

A
T
4

(
p
,
p
+
2
,
r
)

\mathrm {AT4}(p,p+2,r)

-graph are strongly regular with parameters

(

(
p
+
2
)
(

p
2

+
4
p
+
2
)
,
p
(
p
+
3
)
,
p
−
2
,
p

)

\big ((p+2)(p^2+4p+2),p(p+3),p-2,p\big )

. In this paper, an upper bound is found for the prime spectrum of the automorphism group of a strongly regular graph with such parameters, and also some restrictions obtained for the prime spectrum and the structure of the automorphism group of an

A
T
4

(
p
,
p
+
2
,
r
)

\mathrm {AT4}(p,p+2,r)

-graph in the case when

2
>
p

2>p

is a prime power. As a corollary, it is shown that there are no arc-transitive

A
T

(
p
,
p
+
2
,
r
)

\mathrm {AT}(p,p+2,r)

-graphs with

p
∈
{
11
,
17
,
27
}

p\in \{11,17,27\}

.
FRETraj: integrating single-molecule spectroscopy with molecular dynamics
Authors: Steffen Fabio D , Sigel Roland K O , Börner Richard
Published: September 2021

Quantitative interpretation of single-molecule FRET experiments requires a model of the dye dynamics to link experimental energy transfer efficiencies to distances between atom positions. We have developed FRETraj, a Python module to predict FRET distributions based on accessible-contact volumes (ACV) and simulated photon statistics. FRETraj helps to identify optimal fluorophore positions on a biomolecule of interest by rapidly evaluating donor-acceptor distances. FRETraj is scalable and fully integrated into PyMOL and the Jupyter ecosystem. Here, we describe the conformational dynamics of a DNA hairpin by computing multiple ACVs along a molecular dynamics trajectory and compare the predicted FRET distribution with single-molecule experiments. FRET-assisted modeling will accelerate the analysis of structural ensembles in particular dynamic, non-coding RNAs and transient protein-nucleic acid complexes.

Availability and implementation

FRETraj is implemented as a cross-platform Python package available under the GPL-3.0 on Github (https://github.com/RNA-FRETools/fretraj) and is documented at https://RNA-FRETools.github.io/fretraj.

Supplementary information

Supplementary data are available at Bioinformatics online.
Deep Subspace Mutual Learning for cancer subtypes prediction
Authors: Yang Bo , Xin Ting-Ting , Pang Shan-Min , Wang Meng , Wang Yi-Jie
Published: September 2021

Motivation

Precise prediction of cancer subtypes is of significant importance in cancer diagnosis and treatment. Disease etiology is complicated existing at different omics levels; hence integrative analysis provides a very effective way to improve our understanding of cancer.

Results

We propose a novel computational framework, named Deep Subspace Mutual Learning (DSML). DSML has the capability to simultaneously learn the subspace structures in each available omics data and in overall multi-omics data by adopting deep neural networks, which thereby facilitates the subtype’s prediction via clustering on multi-level, single-level and partial-level omics data. Extensive experiments are performed in five different cancers on three levels of omics data from The Cancer Genome Atlas. The experimental analysis demonstrates that DSML delivers comparable or even better results than many state-of-the-art integrative methods.

Availability and implementation

An implementation and documentation of the DSML is publicly available at https://github.com/polytechnicXTT/Deep-Subspace-Mutual-Learning.git.
CellProfiler Analyst 3.0: accessible data exploration and machine learning for image analysis
Authors: Stirling David R , Carpenter Anne E , Cimini Beth A
Published: September 2021

Image-based experiments can yield many thousands of individual measurements describing each object of interest, such as cells in microscopy screens. CellProfiler Analyst is a free, open-source software package designed for the exploration of quantitative image-derived data and the training of machine learning classifiers with an intuitive user interface. We have now released CellProfiler Analyst 3.0, which in addition to enhanced performance adds support for neural network classifiers, identifying rare object subsets, and direct transfer of objects of interest from visualization tools into the Classifier tool for use as training data. This release also increases interoperability with the recently released CellProfiler 4, making it easier for users to detect and measure particular classes of objects in their analyses.

Availability

CellProfiler Analyst binaries for Windows and MacOS are freely available for download at https://cellprofileranalyst.org/. Source code is implemented in Python 3 and is available at https://github.com/CellProfiler/CellProfiler-Analyst/. A sample dataset is available at https://cellprofileranalyst.org/examples, based on images freely available from the Broad Bioimage Benchmark Collection.
Homozygous missense WIPI2 variants cause a congenital disorder of autophagy with neurodevelopmental impairments of variable clinical severity and disease course
Authors: Maroofian Reza , Gubas Andrea , Kaiyrzhanov Rauan , Scala Marcello , Hundallah Khalid , Severino Mariasavina , Abdel-Hamid Mohamed S , Rosenfeld Jill A , Ebrahimi-Fakhari Darius , Ali Zahir , Rahim Fazal , Houlden Henry , Tooze Sharon A , Alsaleh Norah S , Zaki Maha S
Published: September 2021

WIPI2 is a member of the human WIPI protein family (seven-bladed b-propeller proteins binding phosphatidylinositols, PROPPINs), which play a pivotal role in autophagy and has been implicated in the pathogenesis of several neurological conditions. The homozygous WIPI2 variant c.745G>A; p.(Val249Met) (NM_015610.4) has recently been associated with a neurodevelopmental disorder in a single family. Using exome sequencing and Sanger segregation analysis, here, two novel homozygous WIPI2 variants [c.551T>G; p.(Val184Gly) and c.724C>T; p.(Arg242Trp) (NM_015610.4)] were identified in four individuals of two consanguineous families. Additionally, follow-up clinical data were sought from the previously reported family. Three non-ambulant affected siblings of the first family harbouring the p.(Val184Gly) missense variant presented with microcephaly, profound global developmental delay/intellectual disability, refractory infantile/childhood-onset epilepsy, progressive tetraplegia with joint contractures and dyskinesia. In contrast, the proband of the second family carrying the p.(Arg242Trp) missense variant, similar to the initially reported WIPI2 cases, presented with a milder phenotype, encompassing moderate intellectual disability, speech and visual impairment, autistic features, and an ataxic gait. Brain MR imaging in five patients showed prominent white matter involvement with a global reduction in volume, posterior corpus callosum hypoplasia, abnormal dentate nuclei and hypoplasia of the inferior cerebellar vermis. To investigate the functional impact of these novel WIPI2 variants, we overexpressed both in WIPI2-knockout HEK293A cells. In comparison to wildtype, expression of the Val166Gly WIPI2b mutant resulted in a deficient rescue of LC3 lipidation whereas Arg224Trp mutant increased LC3 lipidation, in line with the previously reported Val231Met variant. These findings support a dysregulation of the early steps of the autophagy pathway. Collectively, our findings provide evidence that biallelic WIPI2 variants cause a neurodevelopmental disorder of variable severity and disease course. Our report expands the clinical spectrum and establishes WIPI2-related disorder as a congenital disorders of autophagy.
Association of renin–angiotensin system blockers with COVID-19 diagnosis and prognosis in patients with hypertension: a population-based study
Authors: Soler María José , Ribera Aida , Marsal Josep R , Mendez Ana Belen , Andres Mireia , Azancot Maria Antonia , Oristrell Gerard , Méndez-Boo Leonardo , Cohen Jordana , Barrabés Jose A , Ferreira-González Ignacio ,   Vall d’Hebron COVID-19 Working Group
Published: September 2021

Background

The effect of renin–angiotensin system (RAS) blockade either by angiotensin-converting enzyme inhibitors (ACEis) or angiotensin-receptor blockers (ARBs) on coronavirus disease 2019 (COVID-19) susceptibility, mortality and severity is inadequately described. We examined the association between RAS blockade and COVID-19 diagnosis and prognosis in a large population-based cohort of patients with hypertension (HTN).

Methods

This is a cohort study using regional health records. We identified all individuals aged 18–95 years from 87 healthcare reference areas of the main health provider in Catalonia (Spain), with a history of HTN from primary care records. Data were linked to COVID-19 test results, hospital, pharmacy and mortality records from 1 March 2020 to 14 August 2020. We defined exposure to RAS blockers as the dispensation of ACEi/ARBs during the 3 months before COVID-19 diagnosis or 1 March 2020. Primary outcomes were: COVID-19 infection and severe progression in hospitalized patients with COVID-19 (the composite of need for invasive respiratory support or death). For both outcomes and for each exposure of interest (RAS blockade, ACEi or ARB) we estimated associations in age-, sex-, healthcare area- and propensity score-matched samples.

Results

From a cohort of 1 365 215 inhabitants we identified 305 972 patients with HTN history. Recent use of ACEi/ARBs in patients with HTN was associated with a lower 6-month cumulative incidence of COVID-19 diagnosis {3.78% [95% confidence interval (CI) 3.69–3.86%] versus 4.53% (95% CI 4.40–4.65%); P < 0.001}. In the 12 344 patients with COVID-19 infection, the use of ACEi/ARBs was not associated with a higher risk of hospitalization with need for invasive respiratory support or death [OR = 0.91 (0.71–1.15); P = 0.426].

Conclusions

RAS blockade in patients with HTN is not associated with higher risk of COVID-19 infection or with a worse progression of the disease.
Patients with varying courses of single coronary artery: case series
Authors: Sheng Calvin C , Ghobrial Joanna , Cho Leslie
Published: September 2021

Background

Single coronary artery (SCA) is a rare congenital anomaly where blood to the heart is supplied through a common trunk. Identifying these abnormalities is important because some variants can compromise myocardial blood flow and increase risk of sudden cardiac death.

Case summary

We present five patients with varying Lipton Group I and Group II SCA subtypes, corroborated on multi-imaging modalities and evaluated with comprehensive non-invasive as well as invasive testing. Their clinical presentations also vary from a spectrum of asymptomatic finding to angina equivalent. The decision for definitive surgical intervention involving unroofing of the involved vessel depends largely on symptoms and evidence of myocardial ischaemia.

Discussion

While SCA findings are often incidental and benign, understanding the origin, branching pattern, and course of the anomalous artery has implications in prognosis and treatment. This usually involves a combination of anatomic assessment with imaging such as coronary Computed Tomography Angiography (CTA), Magnetic Resonance Angiography (MRA), and/or coronary angiography as well as functional assessment with invasive testing using tools like instantaneous wave-free ratio and intravascular ultrasound both at rest and with stress. Individualized treatment plans can then be made through a multidisciplinary approach involving adult congenital heart disease specialists and congenital cardiothoracic surgeons.
Cardiac perforation due to delayed migration of a chronic dialysis catheter: a case report
Authors: Jahnke Charlotte , Hoxha Elion , Söffker Gerold , Seiffert Moritz
Published: September 2021

Background

Tunnelled haemodialysis catheters are commonly used to perform haemodialysis. Rare complications of these catheters include perforations of major blood vessels or the heart. Albeit rare, these complications can lead to significant morbidity and mortality.

Case summary

We present a case of late migration of a tunnelled haemodialysis catheter causing a right atrial perforation with subsequent pericardial tamponade, haemodynamic shock, and cardiac arrest. A 51-year-old female patient with end-stage renal disease presented with hypotension and lactate acidosis, indicating circulatory shock, during ambulatory intermittent haemodialysis. Dialysis was performed through a tunnelled haemodialysis catheter that had been implanted more than 1 year ago. Upon admission to the hospital, initial diagnostics, including transthoracic echocardiography and computed tomography scan, showed a circumferential pericardial effusion which was not haemodynamically significant and no other pathological findings. After being transferred to the intensive care unit, the patient again showed signs of haemodynamic shock at the start of another dialysis session which deteriorated to cardiac arrest. Ultimately, using multi-modality imaging, migration of the catheter tip through the right atrial wall into the pericardial space was diagnosed. Emergency sternotomy and surgical extraction of the tunnelled haemodialysis catheter were performed and the patient recovered completely.

Discussion

Migration and perforation of a tunnelled haemodialysis catheter can occur late after implantation and lead to circulatory shock, thus requiring immediate diagnostic workup and surgical therapy. Routine diagnostic procedures may be insufficient for making a correct diagnosis. More specific approaches, such as multi-modality imaging including contrast echocardiography, should be implemented upon clinical suspicion.
Estimation of genetic variance contributed by a quantitative trait locus: correcting the bias associated with significance tests
Authors: Xie Fangjie , Wang Shibo , Beavis William D , Xu Shizhong
Published: September 2021

The Beavis effect in quantitative trait locus (QTL) mapping describes a phenomenon that the estimated effect size of a statistically significant QTL (measured by the QTL variance) is greater than the true effect size of the QTL if the sample size is not sufficiently large. This is a typical example of the Winners’ curse applied to molecular quantitative genetics. Theoretical evaluation and correction for the Winners’ curse have been studied for interval mapping. However, similar technologies have not been available for current models of QTL mapping and genome-wide association studies where a polygene is often included in the linear mixed models to control the genetic background effect. In this study, we developed the theory of the Beavis effect in a linear mixed model using a truncated noncentral Chi-square distribution. We equated the observed Wald test statistic of a significant QTL to the expectation of a truncated noncentral Chi-square distribution to obtain a bias-corrected estimate of the QTL variance. The results are validated from replicated Monte Carlo simulation experiments. We applied the new method to the grain width (GW) trait of a rice population consisting of 524 homozygous varieties with over 300 k single nucleotide polymorphism markers. Two loci were identified and the estimated QTL heritability were corrected for the Beavis effect. Bias correction for the larger QTL on chromosome 5 (GW5) with an estimated heritability of 12% did not change the QTL heritability due to the extremely large test score and estimated QTL effect. The smaller QTL on chromosome 9 (GW9) had an estimated QTL heritability of 9% reduced to 6% after the bias-correction.
Dynamic sampling bias and overdispersion induced by skewed offspring distributions
Authors: Okada Takashi , Hallatschek Oskar
Published: September 2021

Natural populations often show enhanced genetic drift consistent with a strong skew in their offspring number distribution. The skew arises because the variability of family sizes is either inherently strong or amplified by population expansions. The resulting allele-frequency fluctuations are large and, therefore, challenge standard models of population genetics, which assume sufficiently narrow offspring distributions. While the neutral dynamics backward in time can be readily analyzed using coalescent approaches, we still know little about the effect of broad offspring distributions on the forward-in-time dynamics, especially with selection. Here, we employ an asymptotic analysis combined with a scaling hypothesis to demonstrate that over-dispersed frequency trajectories emerge from the competition of conventional forces, such as selection or mutations, with an emerging time-dependent sampling bias against the minor allele. The sampling bias arises from the characteristic time-dependence of the largest sampled family size within each allelic type. Using this insight, we establish simple scaling relations for allele-frequency fluctuations, fixation probabilities, extinction times, and the site frequency spectra that arise when offspring numbers are distributed according to a power law.
Age-Related Differences of Rumination on the Loneliness–Depression Relationship: Evidence From a Population-Representative Cohort
Authors: Tong Horace , Hou Wai Kai , Liang Li , Li Tsz Wai , Liu Huinan , Lee Tatia M C
Published: September 2021

Background and Objectives

This study examined the association of loneliness with depressive symptoms across various age groups. Loneliness is a significant risk factor for precipitating depressive symptoms. Rumination, a mechanism that underpins depression, can become intense when a person feels lonely. In addition, age is a major factor associated with changes in mental and physical health. Thus, the importance of rumination and age in moderating the loneliness–depression link were investigated.

Research Design and Methods

This cross-sectional study was conducted during the acute phase of the coronavirus disease 2019 pandemic in Hong Kong (February 27 to March 17, 2020). A population-representative sample of 1,972 people (1,107 females; 18–92 years of age) was recruited and interviewed via telephone through random digit dialing. This sample included 394 younger adults (18–30 years), 1,106 middle-aged adults (31–64 years), and 472 older adults (65 years or above). Respondents reported depressive symptoms, subjective loneliness, state rumination, and sociodemographic factors.

Results

Loneliness and rumination were positively associated with depressive symptoms, and they significantly interacted in predicting cognitive-affective symptoms. Further analysis of age showed that the interaction was significant only in middle-aged adults and older adults. Both rumination and age interacted with loneliness, respectively, in predicting cognitive-affective symptoms.

Discussion and Implications

These findings indicate that the strength of the association between loneliness and the cognitive-affective symptoms of depression depends on rumination levels and age. An intervention to regulate rumination offers a feasible direction for health care and social care aimed at improving older adults’ mental health.
Negative Perception of Aging Is Associated With Frailty Transitions Within a Cohort of Sexual Minority Men
Authors: Nieves-Lugo Karen , Ware Deanna , Althoff Keri , Brennan-Ing Mark , Meanley Steven , Brown Andre L , Haberlen Sabina A , Masters Mary , Egan James E , Friedman Mackey R , Plankey Michael
Published: September 2021

Background and Objectives

Older people have an increased risk of developing frailty, an age-related clinical syndrome associated with worse health outcomes. This study examined the effect of self-perception of aging (ie, age discrepancy—individuals feel younger/older than their chronological age and aging satisfaction) on frailty transitions.

Research Design and Methods

We use longitudinal data from 549 HIV−/499 HIV+ sexual minority men aged 50 years or older enrolled in the Multicenter AIDS Cohort Study. To test the association of self-perception of aging on transitions between states of frailty (nonfrail/frail), defined using Fried Frailty Phenotype, a multinomial modeling was used.

Results

With remaining nonfrail as the referent group, participants reporting low aging satisfaction (vs moderate aging satisfaction) had increased odds of transitioning from nonfrail to frail (odds ratio [OR]: 2.72; 95% confidence interval [CI]: 1.56–4.74), frail to nonfrail (OR: 3.40; 95% CI: 1.62–7.12), or remaining frail (frail to frail; OR: 6.64; 95% CI: 3.88–11.38). Participants reporting older subjective age (vs no age discrepancy) had increased odds of transitioning from nonfrail to frail (OR: 2.50; 95% CI: 1.11–5.64), frail to nonfrail (OR: 4.47; 95% CI: 1.85–10.81), or remaining frail (frail to frail; OR: 5.68; 95% CI: 3.06–10.56). High aging satisfaction and younger subjective age were not statistically associated with frailty transitions.

Discussion and Implications

Our findings show that negative self-perception of aging (ie, older subjective age and low aging satisfaction) is associated with frailty transitions (nonfrail to frail, frail to nonfrail, and frail to frail) when compared to remaining nonfrail.
Tissue heterogeneity is prevalent in gene expression studies
Authors: Sturm Gregor , List Markus , Zhang Jitao David
Published: September 2021

Lack of reproducibility in gene expression studies is a serious issue being actively addressed by the biomedical research community. Besides established factors such as batch effects and incorrect sample annotations, we recently reported tissue heterogeneity, a consequence of unintended profiling of cells of other origins than the tissue of interest, as a source of variance. Although tissue heterogeneity exacerbates irreproducibility, its prevalence in gene expression data remains unknown. Here, we systematically analyse 2 667 publicly available gene expression datasets covering 76 576 samples. Using two independent data compendia and a reproducible, open-source software pipeline, we find a prevalence of tissue heterogeneity in gene expression data that affects between 1 and 40% of the samples, depending on the tissue type. We discover both cases of severe heterogeneity, which may be caused by mistakes in annotation or sample handling, and cases of moderate heterogeneity, which are likely caused by tissue infiltration or sample contamination. Our analysis establishes tissue heterogeneity as a widespread phenomenon in publicly available gene expression datasets, which constitutes an important source of variance that should not be ignored. Consequently, we advocate the application of quality-control methods such as BioQC to detect tissue heterogeneity prior to mining or analysing gene expression data.
Regulatory Forbearance in the U.S. Insurance Industry: The Effects of Removing Capital Requirements for an Asset Class
Authors: Becker Bo , Opp Marcus M , Saidi Farzad
Published: September 2021

We analyze the effects of a reform of capital regulation for U.S. insurance companies in 2009. The reform eliminates capital buffers against unexpected losses associated with portfolio holdings of MBS, but not for other fixed-income assets. After the reform, insurance companies are much more likely to retain downgraded MBS compared to other downgraded assets. This pattern is more pronounced for financially constrained insurers. Exploiting discontinuities in the reform’s implementation, we can identify the relevance of the capital requirements channel. We also document that the insurance industry crowds outs other investors in the new issuance of (high-yield) MBS.

Authors have furnished an Internet Appendix, which is available on the Oxford University Press Web site next to the link to the final published paper online.
Pilot evaluation of a personalized commercial program on weight loss, health outcomes, and quality of life
Authors: Hales Sarah B , Schulte Erica M , Turner Tonya F , Malcolm Robert , Wojtanowski Alexis C , Rethorst Chad , Pinto Angela M , Foster Gary D , O’Neil Patrick M
Published: September 2021

WW is a validated behavioral weight management program that encourages healthy habits. WW developed a method of personalizing the SmartPoints® budget depending on dietary and lifestyle preferences, and participants were placed into one of three plans as a pilot evaluation of this new program. In this 6-month, single-arm pilot study, participants attended weekly workshops and used an app to monitor eating and physical activity. Baseline and 6-month assessments included weight, waist circumference, blood pressure, energy intake, cravings, happiness, health-related quality of life, hunger, and fullness. Of 145 adults assessed at baseline, 126 (87%) provided follow-up data. Pre–post changes showed significant reductions in body weight (7.39% ± 5.93%), calories consumed (24.79% ± 32.35%) and significant improvements in cravings, happiness, all SF-36 scales and hunger but not in fullness. Greater % weight loss was related to greater improvements in happiness (r = .38, p < .001), general health perceptions (r = .29, p = .001), and health change (r = .31, p = .001), and greater reduction in role limitations due to personal or emotional problems (r = .24, p = .01). Greater % reduction in caloric intake was associated with greater reductions in cravings (r = .23, p = .01), as well as with greater improvements in happiness (r = .23, p = .01), physical functioning (r = .23, p = .01), and general health perceptions (r = .23, p = .01). Participants in this modified program achieved significant weight loss, regardless of dietary plan, as well as improvements in a variety of other physical and psychological constructs. Those who achieved greater reductions in weight also reported greater improvements in cravings, happiness and some quality of life measures.
Selective Anterior Fusion Surgery Does Not Influence Global Spinal Sagittal Alignment in Lenke Type 5 Adolescent Idiopathic Scoliosis Patients
Authors: Okubo Toshiki , Konomi Tsunehiko , Yanai Yoshihide , Furukawa Mitsuru , Fujiyoshi Kanehiro , Yamane Junichi , Asazuma Takashi , Yato Yoshiyuki
Published: September 2021

Study Design.

Retrospective comparative study.

Objective.

The aim of this study was to evaluate the changes in global spinal sagittal alignment (GSSA) following selective anterior spinal fusion (ASF) in patients with Lenke type 5 adolescent idiopathic scoliosis (AIS).

Summary of Background Data.

Few studies have assessed the changes in postoperative GSSA, including cervical, thoracic, and lumbosacral sagittal alignment in AIS patients with major thoracolumbar/lumbar (TL/L) curve who underwent selective ASF.

Methods.

Fifty-two patients with Lenke type 5 AIS (two males and 50 females, mean age at surgery of 16.4 ± 3.1 years) were included in this study. The average final follow-up was 8.3 ± 3.1 years after surgery. The variations of outcome variables were analyzed in various spinal sagittal profiles using radiographic outcomes (pre-operation, immediate post-operation, and final follow-up). The clinical outcomes at the final follow-up were assessed using Scoliosis Research Society (SRS)-22 and Oswestry Disability Index (ODI) questionnaires.

Results.

The mean Cobb angle of the main TL/L and minor thoracic curve was significantly improved after selective ASF, which was maintained up to the final follow-up. However, in all cases, the various sagittal parameters examined (sagittal vertical axis [SVA], C2–7 SVA, C2–7 lordosis, T1 slope, thoracic kyphosis, T10-L2 kyphosis, lumbar lordosis, pelvic incidence, pelvic tilt, and sacral slope), did not significantly change in the immediate postoperative period, and all GSSA parameters were maintained up to the final follow-up. Furthermore, the magnitude of coronal curve correction and fused levels did not affect each GSSA parameter postoperatively. During the period up to the final follow-up, no significant clinical symptoms were observed. The final SRS-22 global score was 4.5 ± 0.3, and ODI scored 0.8 ± 2.4.

Conclusion.

Selective ASF did not influence various GSSA parameters postoperatively and could maintain excellent correction for coronal deformity with satisfactory final functional and clinical outcomes confirmed by long-term follow-up.

Level of Evidence: 4