bluuebunny/crossref_metadata_2025 huggingface dataset:
Fabrication of thermal energy storage wood composite based on shape-stable phase change material
Authors: Liu Jingyi , Jia Shifang , Lin Xianxian , Cao Huimin , Wang Wenbin , Guo Xi , Sun Weisheng
Published: May 2021

In this work, a novel phase change energy storage wood (PCESW) was fabricated by impregnating solid-solid phase change materials (SSPCM) into delignified wood. The SSPCM was prepared by using polyethylene glycol (PEG) 1500 as the thermal energy storage ingredient, hexamethylene diisocyanate (HDI) as the cross-linking agent and castor oil (CO) as the skeleton material. The chemical composition and structure of SSPCM and PCESW were confirmed by fourier transform infrared spectroscopy (FTIR); the crystalline structure of PEG and SSPCM were tested by x-ray diffraction (XRD); the microstructure of PCESW was observed by scanning electron microscopy (SEM); thermal properties and durability of SSPCM and PCESW were investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TG). The results showed that: (1) the porosity of wood was improved obviously after delignification and SSPCM mainly distributed in wood vessels; (2) PCESW-15 exhibited superior temperature-regulating performance and thermal stability; (3) PCESW-15 presented outstanding shape stability and no liquid leakage occurred during the phase transition. The great thermal performance of PCESWs suggested that it can be used as energy-saving building materials for indoor temperature regulating.
Influence of boss-backing welding to ERW pipe
Authors: Luo Jinheng , Zhao Xinwei , Liu Ming , Luo Sheji , Hu Meijuan , Wu Gang , Li Lifeng , Zhu Lixia
Published: May 2021

Station and valve chamber design often encounter the situation of drilling hole at the main pipeline and welding boss-backing to connect the branch pipe. Boss hole location should generally be at least 100 mm away from the longitudinal weld or spiral weld. However, because the electric resistance weld (ERW) is difficult to distinguish in practice, some bosses mounting position coincide with ERW or close to. In this paper, the influence of boss-backing welding directly on the longitudinal weld to the original residual stresses of ERW pipe was studied. The microstructure of pipe body and longitudinal weld after welding was also analysis. The testing results showed that the overall residual stresses of ERW pipe were relatively small. Residual stress at the longitudinal weld region were smaller than those at the pipe body region. After the boss-backing welding, the axial residual stress at the longitudinal weld and the circumferential residual stress at the pipe body region near the intersection increased sharply to 2.5 (444 MPa) and 3.8 (433 MPa) times, respectively. The invaded width and depth to the ERW pipe after welding were about 15.167 mm and 3.376 mm. Granular bainite with necklace type M-A constituents could be observed at the invaded zone. It is suggested that small welding heat input should be adopted for boss-backing welding.
Transcervical microwave ablation in type 2 uterine fibroids via a hysteroscopic approach: analysis of ablation profiles
Authors: Zia Ghina , Sebek Jan , Schenck Jessica , Prakash Punit
Published: May 2021

Type 2 uterine fibroids are challenging to resect surgically as ≥ 50% volume of myoma lies within the myometrium. A hysteroscopic approach for ablating fibroids is minimally-invasive, but places a considerable burden on the operator to accurately place the ablation applicator within the target. We investigated the sensitivity of transcervical microwave ablation outcome with respect to position of the ablation applicator within 1 – 3 cm type 2 fibroids. Methods: A finite element computer model was developed to simulate 5.8 GHz microwave ablation of fibroids and validated with experiments in ex vivo tissue. The ablation outcome was evaluated with respect to applicator insertion angles (30°, 45°, 60°) , depth and offset from the fibroid center (±2 mm for 3 cm fibroid and ±1 mm for 1 cm fibroid) with 35 W and 15 W applied power for 3 cm and 1 cm fibroids, respectively. Power deposition was stopped when thermal dose of 40 cumulative equivalent minutes at 43 °C (CEM43) was accrued in adjacent myometrium. Results: Within the range of all evaluated insertion angles, depths and offsets, the ablation coverage was less sensitive to variation in angle as compared to depth and offset, and ranged from 34.9 – 83.6% for 3 cm fibroid in 140 – 400 s and 34.1 – 67.9% for 1 cm fibroid in 30 – 50 s of heating duration. Maximum achievable ablation coverage in both fibroid cases reach ∼ 90% if thermal dose is allowed to exceed 40 CEM43 in myometrium. Conclusion: The study demonstrates the technical feasibility of transcervical microwave ablation for fibroid treatment and the relationship between applicator position within the fibroid and fraction of fibroid that can be ablated while limiting thermal dose in adjacent myometrium.
A simple process to create micro-gaps in printed copper electrodes by sintering induced stress in flexible PET substrates
Authors: Wu Xinzhou , Yuan Wei , Su Wenming , Cui Zheng , Zhu Simeng , Deng Ming
Published: May 2021

A new simple low-cost technique for fabricating micro-gaps of less than 50 µm in copper electrodes is reported, which combines conventional screen printing of copper paste and intense pulsed light (IPL) sintering. The micro-gap is created via a two-step IPL sintering. First, a continuous printed copper stripe is half sintered along its length with another half blocked by an opaque mask. Then, the second sintering is performed over the entire length of copper stripe with the opaque mask removed. At the joint between two sintering steps, a micro-gap is formed across the copper stripe due to thermal contraction of underlying polyethylene terephthalate substrate. The width of copper micro-gaps can be adjusted by IPL energy. Simple light emitting diode circuits have been made by the micro-gap electrodes, demonstrating its feasibility for practical applications.
Formulation and characterization of screen printable dopant ink for fabrication of polysilicon TFTs
Authors: Ito Mao , Kamath Arvind
Published: May 2021

To move the promise of printed electronics from the laboratory to volume production required adopting a new approach eliminating ink-jet printing and adopting instead a hybrid mature print and conventional process. Novel screen printable N+ and P+ dopant inks were developed to fabricate polysilicon thin film transistors (TFTs). Semiconductor-grade dopant inks were formulated from a combination of thermoset plastic with boron and phosphor compounds. Inks were screen printed on polysilicon active islands on a 300 mm square stainless-steel foil substrate. The drain and source of the top gate TFTs were then formed via a thermal anneal activation. The residue after annealing was removed with an inoffensive process to avoid damage to the thin silicon layer and gate oxide. Doping was uniform across 300 mm sheet substrate. The sheet resistance was modulated to 200 Ω sq−1 for the N+ and 1000 Ω sq−1 for the P+ active layer. Field mobility of polysilicon TFTs fabricated using this screen-printed dopant process were 80 cm2V s−1 for PMOS and 200 cm2V s−1 for NMOS using low-cost, mature equipment, and an easily manageable process that is both scalable and compatible with roll-to-roll manufacturing.
A chain of three dimensional scatterers under quasi-one dimensional quantum confinement: a Green’s function approach to energy band engineering
Authors: Kim J. I.
Published: May 2021

A mechanism to modify the energy band structure is proposed by considering a chain of periodic scatterers forming a linear lattice (akin to an optical lattice for ultracold atoms) around which an external cylindrical trapping potential is applied along the chain axis. It is analytically shown that, when this trapping (confining) potential is tight enough so as to reduce the dimensionality of the problem to an effective one dimension, it may modify the bound and scattering states of the local lattice potential, whose three-dimensional nature around each site is fully taken into account and going beyond the zero-range contact-potential approximation. Since these states contribute to the formation of the energy bands, the latter could thereby be continuously tuned by manipulating the confinement without the need to change the lattice potential. Such dimensionality reduction by quantum confinement is analyzed by using a Green’s functions method that can describe the scattering off the lattice sites in the presence of strong confinement and that can collect the contribuitions of several scattering partial waves.
Irradiance transport equation applied to propagation of wavefront obtained by the Bi-Ronchi test using point cloud
Authors: Arriaga Hernández J A , Cuevas Otahola B T , Oliveros Oliveros J , Jaramillo Núñez A , Morín Castillo M
Published: May 2021

In this work, we show a Bi-Ronchi test (BRT) proposal using point cloud for sensing the whole surface and wavefront of spherical mirrors as a fast computational test with efficiency comparable with the Ronchi test. We also show an application of the Irradiance Transport equation based on the differential form of the circular Zernike polynomials, to obtain the Phase Transport equation, with capabilities to study the wavefront propagation. To this aim, we experimentally analyze the propagation of W with the BRT, to validate the experimental propagation performed with the Irradiance Transport Equation, giving place to a Phase Transport equation. For this purpose, we use square rulings to observe bi-Ronchigrams and their corresponding Transversal Aberrations as well as their W. We validated our results by comparing the BRT with the Ronchi Test for several measurements of a given wavefront W with Ronchi rulings in the same position. Three different bRR were placed in several locations before and beyond the mirror curvature Radius in order to characterize the experimental propagation of W and test the reflection relation of W before and beyond the mirror Curvature Radius. Finally, we use the Phase Transport equation to analyze the propagation of an efficient W in terms of the differential circular Zernike Polynomials in order to obtain a Riemann-integrable function to numerically find a solution for validating the experimental propagation, the symmetry of the wavefronts, the existence of a symmetry matrix, and the BRT.
Convolutional neural network based non-iterative reconstruction for accelerating neutron tomography
*
Authors: Venkatakrishnan Singanallur , Ziabari Amirkoushyar , Hinkle Jacob , Needham Andrew W , Warren Jeffrey M , Bilheux Hassina Z
Published: May 2021

Neutron computed tomography (NCT), a 3D non-destructive characterization technique, is carried out at nuclear reactor or spallation neutron source-based user facilities. Because neutrons are not severely attenuated by heavy elements and are sensitive to light elements like hydrogen, neutron radiography and computed tomography offer a complementary contrast to x-ray CT conducted at a synchrotron user facility. However, compared to synchrotron x-ray CT, the acquisition time for an NCT scan can be orders of magnitude higher due to lower source flux, low detector efficiency and the need to collect a large number of projection images for a high-quality reconstruction when using conventional algorithms. As a result of the long scan times for NCT, the number and type of experiments that can be conducted at a user facility is severely restricted. Recently, several deep convolutional neural network (DCNN) based algorithms have been introduced in the context of accelerating CT scans that can enable high quality reconstructions from sparse-view data. In this paper, we introduce DCNN algorithms to obtain high-quality reconstructions from sparse-view and low signal-to-noise ratio NCT data-sets thereby enabling accelerated scans. Our method is based on the supervised learning strategy of training a DCNN to map a low-quality reconstruction from sparse-view data to a higher quality reconstruction. Specifically, we evaluate the performance of two popular DCNN architectures—one based on using patches for training and the other on using the full images for training. We observe that both the DCNN architectures offer improvements in performance over classical multi-layer perceptron as well as conventional CT reconstruction algorithms. Our results illustrate that the DCNN can be a powerful tool to obtain high-quality NCT reconstructions from sparse-view data thereby enabling accelerated NCT scans for increasing user-facility throughput or enabling high-resolution time-resolved NCT scans.
Unsupervised machine learning of topological phase transitions from experimental data
Authors: Käming Niklas , Dawid Anna , Kottmann Korbinian , Lewenstein Maciej , Sengstock Klaus , Dauphin Alexandre , Weitenberg Christof
Published: May 2021

Identifying phase transitions is one of the key challenges in quantum many-body physics. Recently, machine learning methods have been shown to be an alternative way of localising phase boundaries from noisy and imperfect data without the knowledge of the order parameter. Here, we apply different unsupervised machine learning techniques, including anomaly detection and influence functions, to experimental data from ultracold atoms. In this way, we obtain the topological phase diagram of the Haldane model in a completely unbiased fashion. We show that these methods can successfully be applied to experimental data at finite temperatures and to the data of Floquet systems when post-processing the data to a single micromotion phase. Our work provides a benchmark for the unsupervised detection of new exotic phases in complex many-body systems.
Linear mappings preserving the copositive cone
Authors: Shitov Yaroslav
Published: May 2021

Let

S

n

\mathcal {S}_n

be the set of all

n
n

-by-

n
n

symmetric real matrices, and let

C

n

\mathcal {C}_n

be the copositive cone, that is, the set of all matrices

a
∈

S

n

a\in \mathcal {S}_n

that fulfill the condition

u
⊤

a
u
⩾
0

u^\top a u\geqslant 0

for all

n
n

-vectors

u
u

with nonnegative entries. We prove that a linear mapping

φ
:

S

n

→

S

n

\varphi :\mathcal {S}_n\to \mathcal {S}_n

satisfies

φ
(

C

n

)
=

C

n

\varphi (\mathcal {C}_n)=\mathcal {C}_n

if and only if

φ
(
x
)
=

m
⊤

x
m

\begin{equation*} \varphi (x)=m^\top xm \end{equation*}

for a fixed monomial matrix

m
m

with nonnegative entries.
Rubio de Francia extrapolation theorem and related topics in the theory of elliptic and parabolic equations. A survey
Authors: Krylov N.
Published: May 2021

This is a brief historical overview of the Sobolev mixed norm theory of linear elliptic and parabolic equations and the recent development in this theory based on the Rubio de Francia extrapolation theorem. A self-contained proof of this theorem along with other relevant tools of Real Analysis are also presented as well as an application to mixed norm estimates for fully nonlinear equations.
Lagrange multipliers for evolution problems with constraints on the derivatives
Authors: Azevedo A. , Rodrigues J. , Santos L.
Published: May 2021

The existence of generalized Lagrange multipliers is proved for a class of evolution problems for linear differential operators of various types subject to constraints on the derivatives. Those Lagrange multipliers and the respective solutions are stable for the vanishing of the coercive parameter and are naturally associated with evolution variational inequalities with time-dependent convex sets of gradient type. These results are applied to the sandpile problem, to superconductivity problems, to flows of thick fluids, to problems with the biharmonic operator, and to first order vector fields of subelliptic type.
On meso-scale approximations for vibrations of membranes with lower-dimensional clusters of inertial inclusions
Authors: Maz′ya V. , Movchan A. , Nieves M.
Published: May 2021

Formal asymptotic algorithms are considered for a class of meso-scale approximations for problems of vibration of elastic membranes that contain clusters of small inertial inclusions distributed along contours of predefined smooth shapes. Effective transmission conditions have been identified for inertial structured interfaces, and approximations to solutions of eigenvalue problems have been derived for domains containing lower-dimensional clusters of inclusions.
A note on weak solutions to the Navier–Stokes equations that are locally in 𝐿_{∞}(𝐿^{3,∞})
Authors: Seregin G.
Published: May 2021

The objective of the note is to prove a regularity result for weak solutions to the Navier–Stokes equations that are locally in

L
∞

(

L

3
,
∞

)

L_\infty (L^{3,\infty })

. It reads that, in a sense, the number of singular points at each time is at most finite. This note is inspired by a recent paper of H. J. Choe, J. Wolf, M. Yang.
Structure–activity relationships of antityrosinase and antioxidant activities of cinnamic acid and its derivatives
Authors: Chen Jianmin , Ran Mengnan , Wang Meixia , Liu Xinying , Liu Siwan , Yu Yue
Published: May 2021

The related structure–activity relationships of cinnamic acid and its derivates have not been studied in details yet. Herein, antityrosinase and antioxidant activities of 18 compounds were evaluated. The results demonstrated that the substituents on the phenyl ring of cinnamic acid led to the enhancement of the inhibition on monophenolase and the weakening of the inhibition on diphenolase. Among these tested compounds, 9 was first discovered as a tyrosinase inhibitor in a reversible competitive manner with IC50 value of 68.6 ± 4.2 µm. Docking results demonstrated 9 located into the catalytic center of tyrosinase. Antioxidant assay indicated that only 1 hydroxyl group on the phenyl ring was not enough to possess the radical scavenging activity, and the number of hydroxyl groups may be more important. This study will be helpful in the development of new cinnamic acid derivates as tyrosinase inhibitors and antioxidants with higher efficacy.
A predictive paradigm for COVID-19 prognosis based on the longitudinal measure of biomarkers
Authors: Chen Xin , Gao Wei , Li Jie , You Dongfang , Yu Zhaolei , Zhang Mingzhi , Shao Fang , Wei Yongyue , Zhang Ruyang , Lange Theis , Wang Qianghu , Chen Feng , Lu Xiang , Zhao Yang
Published: May 2021

Novel coronavirus disease 2019 (COVID-19) is an emerging, rapidly evolving crisis, and the ability to predict prognosis for individual COVID-19 patient is important for guiding treatment. Laboratory examinations were repeatedly measured during hospitalization for COVID-19 patients, which provide the possibility for the individualized early prediction of prognosis. However, previous studies mainly focused on risk prediction based on laboratory measurements at one time point, ignoring disease progression and changes of biomarkers over time. By using historical regression trees (HTREEs), a novel machine learning method, and joint modeling technique, we modeled the longitudinal trajectories of laboratory biomarkers and made dynamically predictions on individual prognosis for 1997 COVID-19 patients. In the discovery phase, based on 358 COVID-19 patients admitted between 10 January and 18 February 2020 from Tongji Hospital, HTREE model identified a set of important variables including 14 prognostic biomarkers. With the trajectories of those biomarkers through 5-day, 10-day and 15-day, the joint model had a good performance in discriminating the survived and deceased COVID-19 patients (mean AUCs of 88.81, 84.81 and 85.62% for the discovery set). The predictive model was successfully validated in two independent datasets (mean AUCs of 87.61, 87.55 and 87.03% for validation the first dataset including 112 patients, 94.97, 95.78 and 94.63% for the second validation dataset including 1527 patients, respectively). In conclusion, our study identified important biomarkers associated with the prognosis of COVID-19 patients, characterized the time-to-event process and obtained dynamic predictions at the individual level.
Rapid T-cell receptor interaction grouping with ting
Authors: Mölder Felix , Stervbo Ulrik , Loyal Lucie , Bacher Petra , Babel Nina , Rahmann Sven
Published: May 2021

Motivation

Clustering T-cell receptor repertoire (TCRR) sequences according to antigen specificity is challenging. The previously published tool GLIPH needs several days to weeks for clustering large repertoires, making its use impractical in larger studies. In addition, the methodology used in GLIPH suffers from shortcomings, including non-determinism, potential loss of significant antigen-specific sequences or inclusion of too many unspecific sequences.

Results

We present an algorithm for clustering TCRR sequences that scales efficiently to large repertoires. We clustered 36 real datasets with up to 62 000 unique CDR3β sequences using both an implementation of our method called ting, GLIPH and its successor GLIPH2. While GLIPH required multiple weeks, ting only needed about one minute for the same task. GLIPH2 is comparably fast, but uses a different grouping paradigm. In addition, we found that in naïve repertoires, where no or very few antigen-specific CDR3 sequences or clusters should exist, our method indeed selects much fewer motifs and produces smaller clusters.

Availability and implementation

Our method has been implemented in Python as a tool called ting. It is available from GitHub (https://github.com/FelixMoelder/ting) or PyPI under the MIT license.

Supplementary information

Supplementary data are available at Bioinformatics online.
PaIntDB: network-based omics integration and visualization using protein–protein interactions in Pseudomonas aeruginosa
Authors: Castillo-Arnemann Javier J , Solodova Olga , Dhillon Bhavjinder K , Hancock Robert E W
Published: May 2021

The Pseudomonas aeruginosa Interaction Database, PaIntDB, is an intuitive web-based tool for network-based systems biology analyses using protein–protein interactions (PPI) in this medically important pathogen. It enables the integration and visualization of omics analyses including RNA-Seq and Tn-Seq. High-throughput datasets can be mapped onto PPI networks, which can be explored visually and filtered to uncover novel putative molecular pathways related to the conditions of study. PaIntDB contains the most comprehensive P.aeruginosa interactome to date, collected from a variety of resources, including interactions predicted computationally to further expand analysis capabilities. The web server implementation makes it easily extendable to other bacterial species.

Availability and implementation

PaIntDB is freely available at https://www.paintdb.ca, the source code and database file are available at https://github.com/yavyx/PaIntDB.

Supplementary information

Supplementary data are available at Bioinformatics online.
Target–Decoy MineR for determining the biological relevance of variables in noisy datasets
Authors: Ovando-Vázquez Cesaré , Cázarez-García Daniel , Winkler Robert
Published: May 2021

Motivation

Machine learning algorithms excavate important variables from big data. However, deciding on the relevance of identified variables is challenging. The addition of artificial noise, ‘decoy’ variables, to raw data, ‘target’ variables, enables calculating a false-positive rate and a biological relevance probability for each variable rank. These scores allow the setting of a cut-off for informative variables, depending on the required sensitivity/specificity of a scientific question.

Results

We tested the function of the Target–Decoy MineR (TDM) using synthetic data with different degrees of perturbation. Following, we applied the TDM to experimental Omics (metabolomics, transcriptomics and proteomics) results. The TDM graphs indicate the degree of difference between sample groups. Further, the TDM reports the contribution of each variable to correct classification, i.e. its biological relevance.

Availabilityand implementation

An implementation of the algorithm in R is freely available from https://bitbucket.org/cesaremov/targetdecoy_mining/. The Target–Decoy MineR is applicable to different types of quantitative data in tabular format.

Supplementary information

Supplementary data are available at Bioinformatics online.
CrossTalkeR: analysis and visualization of ligand–receptorne tworks
Authors: Nagai James S , Leimkühler Nils B , Schaub Michael T , Schneider Rebekka K , Costa Ivan G
Published: May 2021

Motivation

Ligand–receptor (LR) network analysis allows the characterization of cellular crosstalk based on single cell RNA-seq data. However, current methods typically provide a list of inferred LR interactions and do not allow the researcher to focus on specific cell types, ligands or receptors. In addition, most of these methods cannot quantify changes in crosstalk between two biological phenotypes.

Results

CrossTalkeR is a framework for network analysis and visualization of LR interactions. CrossTalkeR identifies relevant ligands, receptors and cell types contributing to changes in cell communication when contrasting two biological phenotypes, i.e. disease versus homeostasis. A case study on scRNA-seq of human myeloproliferative neoplasms reinforces the strengths of CrossTalkeR for characterization of changes in cellular crosstalk in disease.

Availability and implementation

CrosstalkeR is an R package available at: Github: https://github.com/CostaLab/CrossTalkeR.

Supplementary information

Supplementary data are available at Bioinformatics online.
Sex Differences in Lifespan Trajectories and Variability of Human Sulcal and Gyral Morphology
Authors: Díaz-Caneja Covadonga M , Alloza Clara , Gordaliza Pedro M , Fernández-Pena Alberto , de Hoyos Lucía , Santonja Javier , Buimer Elizabeth E L , van Haren Neeltje E M , Cahn Wiepke , Arango Celso , Kahn René S , Hulshoff Pol Hilleke E , Schnack Hugo G , Janssen Joost
Published: May 2021

Sex differences in the development and aging of human sulcal morphology have been understudied. We charted sex differences in trajectories and inter-individual variability of global sulcal depth, width, and length, pial surface area, exposed (hull) gyral surface area, unexposed sulcal surface area, cortical thickness, gyral span, and cortex volume across the lifespan in a longitudinal sample (700 scans, 194 participants 2 scans, 104 three scans, age range: 16–70 years) of neurotypical males and females. After adjusting for brain volume, females had thicker cortex and steeper thickness decline until age 40 years; trajectories converged thereafter. Across sexes, sulcal shortening was faster before age 40, while sulcal shallowing and widening were faster thereafter. Although hull area remained stable, sulcal surface area declined and was more strongly associated with sulcal shortening than with sulcal shallowing and widening. Males showed greater variability for cortex volume and lower variability for sulcal width. Our findings highlight the association between loss of sulcal area, notably through sulcal shortening, with cortex volume loss. Studying sex differences in lifespan trajectories may improve knowledge of individual differences in brain development and the pathophysiology of neuropsychiatric conditions.
Weight Change Following Antiretroviral Therapy Switch in People With Viral Suppression: Pooled Data from Randomized Clinical Trials
Authors: Erlandson Kristine M , Carter Christoph C , Melbourne Kathleen , Brown Todd T , Cohen Cal , Das Moupali , Esser Stefan , Huang Hailin , Koethe John R , Martin Hal , McComsey Grace A , Orkin Chloe , Post Frank A , Rockstroh Jürgen K , Sax Paul E , Stellbrink Hans-Jürgen , Waters Laura , Wei Xuelian , Lake Jordan E
Published: May 2021

Background

We sought to identify factors associated with weight gain in randomized clinical trials of antiretroviral therapy (ART) switch.

Methods

We explored the effects of demographic factors, clinical characteristics, and ART on weight gain in a pooled analysis of 12 prospective clinical trials, wherein virologically suppressed people living with human immunodeficiency virus (PWH) were randomized to switch or remain on a stable baseline regimen (SBR).

Results

Both PWH randomized to switch ART (n = 4166) and those remaining on SBR (n = 3150) gained weight. Median weight gain was greater in those who switched (1.6 kg, interquartile range [IQR], –.05 to 4.0 vs 0.4 kg, [IQR], –1.8 to 2.4 at 48 weeks, P < .0001), with most weight gain occurring in the first 24 weeks after switch. Among baseline demographic and clinical characteristics, only younger age and lower baseline body mass index were associated with any or ≥10% weight gain. By week 48, 4.6% gained ≥10% weight (6.4% of switch and 2.2% of SBR), the greatest risk was with switch from efavirenz (EFV) to rilpivirine (RPV) or elvitegravir/cobicistat and switch from tenofovir disoproxil fumarate (TDF) to tenofovir alafenamide (TAF). Switch from abacavir to TAF was associated with less weight gain than switch from TDF to TAF and was not associated with increased risk for ≥10% weight gain.

Conclusions

Moderate weight gain after ART switch was common and usually plateaued by 48 weeks. Baseline ART was a predictor of post-switch weight gain; participants who switched off of EFV and TDF had the greatest weight gain. The biological mechanisms that underlie the differential effects of switching ART agents on weight and associated clinical implications require further study.
The Reliability ofk-Aryn-Cube Based on Component Connectivity
Authors: Lv Mengjie , Fan Jianxi , Zhou Jingya , Yu Jia , Jia Xiaohua
Published: May 2021

Connectivity and diagnosability are two crucial subjects for a network’s ability to tolerate and diagnose faulty processors. The $r$-component connectivity $c\kappa _{r}(G)$ of a network $G$ is the minimum number of vertices whose deletion results in a graph with at least $r$ components. The $r$-component diagnosability $ct_{r}(G)$ of a network $G$ is the maximum number of faulty vertices that the system can guarantee to identify under the condition that there exist at least $r$ fault-free components. This paper first establishes that the $(r+1)$-component connectivity of $k$-ary $n$-cube $Q^{k}_{n}$ is $c\kappa _{r+1}(Q^{k}_{n})=-\frac{1}{2}r^{2}+\Big(2n-\frac{1}{2}\Big)r+1$ for $n\geq 2$, $k\geq 4$ and $1\leq r\leq n$. In view of $c\kappa _{r+1}(Q^{k}_{n})$, we prove that the $(r+1)$-component diagnosabilities of $k$-ary $n$-cube $Q^{k}_{n}$ under the PMC model and MM* model are $ct_{r+1}(Q^{k}_{n})=-\frac{1}{2}r^{2}+\Big(2n-\frac{3}{2}\Big)r+2n$ for $n\geq 4$, $k\geq 4$ and $1\leq r\leq n-1$.
The use of eculizumab as a bridge to retransplantation for chronic antibody-mediated rejection in a heart transplant recipient: a case report
Authors: Kearney Katherine , Macdonald Peter , Hayward Christopher , Muthiah Kavitha
Published: May 2021

Background

Antibody-mediated rejection (AMR) remains a major management challenge in heart transplantation given the complexity of pathological diagnosis and dearth of evidence for effective management. Eculizumab, an anti-C5 monoclonal antibody which inhibits terminal complement activation, has been reported to decrease early AMR in sensitized renal transplant recipients.

Case summary

We report a case of a 29-year-old gentleman with chronic AMR 8 years after heart transplantation, manifesting as significant graft dysfunction. Donor-specific antibodies to DQ7 were found to be causative. Antibody-mediated rejection was managed with quadruple oral immunosuppressive therapy (mycophenolate, prednisolone, everolimus, and tacrolimus) as well as a sequence of broad-spectrum immunological therapies; intravenous (IV) methylprednisolone, plasmapheresis, IV immunoglobulin, rituximab, bortezomib, tocilizumab, and splenic irradiation. No treatment had a sustained impact on donor-specific anti-HLA antibodies (DSAs) or graft function. After testing showed the DQ7 antibodies were complement-binding, a trial of eculizumab was started. This improved DSAs somewhat, and improved graft function and New York Heart Association functional class substantially. The patient was relisted for heart transplantation and successfully retransplanted in March 2018. Specifically, the new organ and recipient were matched at DQ7. After discontinuation of eculizumab, the patient has remained healthy and well, with normal graft function 28 months after retransplantation.

Discussion

To the best of our knowledge, this is the first case of chronic AMR in a heart transplant patient, successfully stabilized with eculizumab and bridged to retransplantation.
The role of some additional risk factors in the occurrence of paroxysmal / persistent atrial fibrillation in patients with arterial hypertension
Authors: Grigoryan S , Hazarapetyan LG , Ter-Markaryan AA , Stepanyan AA
Published: May 2021

Funding Acknowledgements

Type of funding sources: None.

Background

Arterial hypertension (AH) and atrial fibrillation (AF) are two important public health problems and often coexist in the same patient. AH ultimately increases the risk of AF and several pathogenetic mechanisms underlying the higher risk of AF in hypertensive patients are still incompletely known. AH is one of the main reasons for the remodeling process in these patients and makes a significant contribution to the development of structural changes. The aim of this study is to identify predictors of paroxysmal/persistent AF occurrence and progression in hypertensive patients

Methods

In this study where enrolled 109 hypertensive patients with non-valvular paroxysmal/persistent AF (mean age 61.6 ±6.4) who were hospitalized at Institute of Cardiology between 2008 and 2016 year.  As a control group, 44 hypertensive patients without AF were also examined. The study lasted 8 years.  After the enrollment the echocardiography examination and 24-hour ambulatory Holter monitoring ECG were registered in each patient. We measured plasma indexes of inflammation (hsCRP, IL-6) and fibrosis marker - transforming growth factor (TGF-β1). The database consisting of 33 indicators that characterize the clinical, hemodynamic and structural-functional state of the heart, as well as markers of inflammation and fibrosis was created. .All data were analyzed by SPSS 13 and EXCEL - 2013 programs using logistic analysis by odds ratio (OR).

Results

The comparative results of clinical, hemodynamic, inflammation and fibrosis markers OR with  AF in hypertensive patients relative to the control group showed that in hypertensive patients with  AF there was a significant increase in diastolic pressure (OR 1.09, р=0.017) , the number  of hypertensive crises  episodes ( OR 1.56  р=0.001) and patients of older age groups (OR  1.18, р= 0.001) There was a significant deterioration in electrical remodeling  (Pmax 3.92, р=0.001, P dispersion 4.90, р=0.001),  LV diastolic function (isometric ventricular contraction time 1.69, р=0.042) and of left atrial volume (OR 3.69, р=0.001). There were significant increases in levels of inflammatory and fibrosis markers concentrations in comported with hypertensive patients without AF (OR of hsСRP 5.57, р=0.01; IL-6 4.80, р=0.001 and TGF-β1 3.84, р=0.005).

Conclusions

The multifactorial analysis revealed that increased diastolic pressure, frequency of hypertensive crises, age, deterioration of diastolic function, as well as an increase in markers of inflammation and fibrosis concentration are additional risk factors for AF in patients with hypertension.
Importance of medication compliance and lifestyle modification in heart failure readmission: single centre cohort study
Authors: Tun H
Published: May 2021

Funding Acknowledgements

Type of funding sources: None.

Introduction

Medication poor adherence is a common problem among heart failure (HF) patients. Inadequate compliance of drugs lead to increased HF exacerbations, higher risk for hospital admission and death. Despite this recent attention to HF readmission, we know relatively little about its actual causes despite the fact that patients are in many ways best positioned to identify the underlying factors that contribute to their readmissions.

Objective

To systematically investigate the patients" perspectives about the reasons for their hospital readmission related to drug compliance in chronic heart failure patients .

Method and Materials

Patients were recruited for this study was admitted to national institute of cardiovascular diseases, through emergency department. Patients discharged with a primary discharge diagnosis for HF who were then readmitted for any cause in the subsequent 6 month were eligible for the study. Eligible patients were approached, consented, and interviewed within the next 24 hours while they were still in hospital.

Result

For the readmission, median length of stay was 6 days. Total 500 patient included, out of which 375 (75%) were male and most important cause of heart failure is ischaemic cardiomyopathy 400 (80%). No death recorded. Common reasons for readmission are lack of counselling 200(40%), noncompliance medication ; under dose 75(15%), non-compliance 60(12%), volume over load 50(10%), hypertension 50(10%), secondary infection 35(7%).

Conclusion

We concluded that patient compliance of medication, appropriate fluid intake, self-care and life style modification are the important elements to care off according to this study which can be improve with psychotherapies and proper counselling session. For physician side proper information and detail discussion should be done with patient at the time of diagnosis.
HFrEF patient activity levels during COVID-19 lockdown: A comparison between physical activity questionnaires and implantable devices data
Authors: Tsarouchas A , Bakogiannis C , Mouselimis D , Lazaridis C , Kelemanis I , Theofillogiannakos EK , Pagourelias ED , Papadopoulos CE , Fragakis N , Vassilikos VP
Published: May 2021

Funding Acknowledgements

Type of funding sources: None.

Background

The ongoing COVID-19 pandemic is a major public health crisis of great risk to patients with cardiovascular comorbidities. Heart failure (HF) is a deadly chronic disease, a leading cause of hospitalizations worldwide and a great detriment to patients’ quality of life. HF therapy guidelines suggest prescribing physical activity to improve long-term outcomes. Self- or government- imposed behavioral modifications in response to COVID-19 ranging from avoiding social interactions to outright restrictions of movement (lockdowns) could compromise regular PA in HF patients, who constitute an extremely high-risk group.

Purpose

Investigate the effect of the national lockdown in Greece 23rd March – 4th May 2020) on the PA levels of patients suffering from HF with reduced ejection fraction (HFrEF) and cardiac implantable electronic devices (CIEDs).

Methods

HFrEF patients with CIEDs were included in the study. Participants answered the Physical Activity Questionnaire (PAQ) regarding the period before, during and after the 42-day national lockdown. CIED-derived daily activity levels for the corresponding periods were recorded through CIED telemetry. The differences in PAQ- and CIED-derived PA levels and sedentary time before, during and after the lockdown period were investigated.

Results

67 HFrEF patients participated in the study (mean age 69 ± 10.2y, 85% male). Activity levels fell in 55 (82%) of patients. The median PAQ-derived PA level decreased by 28% during lockdown, from 840.5 (944) METmin/week to 602 (1054) METmin/week during the lockdown (p = 0.01). A 53% increase was observed after the lockdown, to 924 (1214) METmin/week (p = 0.004). The CIED-derived activity level was 2.38 (1.3) hours/day pre-lockdown, 1.78 (1.1) hours/day during the lockdown (25% decrease, p < 0.001) and 2.69 (1.5) hours/day post-lockdown (51% increase, p < 0.001). Time spent on sedentary activities also increased to 9 (3) hours per day during the lockdown, up from 6.5 (4) hours before lockdown (p = 0.001).

Conclusions

All measures examined in this study indicate that the COVID-19 lockdown period was associated with a significant decrease in HFrEF patients’ PA. All efforts must be made on the part of clinicians and public health organizations to promote safe exercise in this subgroup of the population that is particularly vulnerable to the effects of a sedentary lifestyle.

Abstract Figure. Patient activity around COVID lockdown
Impact of age and sex on subclinical coronary atherosclerosis in a healthy asian population
Authors: Wong M , Yap J , Yeo KK
Published: May 2021

Funding Acknowledgements

Type of funding sources: None.

Background and Aims

The influence of age and gender on clinical atherosclerotic cardiovascular disease is well reported, but literature remains sparse on whether these extend to the disease in its preclinical stage. We aim to report the prevalence, risk-factors and impact of age and gender on the burden of subclinical coronary atherosclerosis in a healthy Asian population.

Methods

Healthy subjects aged 30-69 years old, with no history of cardiovascular disease or diabetes were recruited from the general population. Subclinical coronary atherosclerosis was quantified via the Coronary Artery Calcium Score (CACS) with CACS of 0 indicating the absence of calcified plaque, 1 to 10 minimal plaque, 11 to 100 mild plaque, and >100 moderate to severe plaque.

Results

A total of 663 individuals (mean age 49.4 ± 9.2 years, 44.8% male) were included. The prevalence of any CAC was 29.3% with 9% having CAC > 100.  The prevalence was significantly higher in males than females (43.1 vs 18.0%, p < 0.001). These gender differences became increasingly pronounced with increasing age, especially in those with moderate-severe CAC. Multivariable analysis revealed significant associations between increasing age, male, higher blood pressure, increased glucose levels and higher LDL cholesterol levels with the presence of any CAC. LDL cholesterol was more significantly associated with CAC in females compared to males (Pinteraction = 0.022).

Conclusions

The prevalence of preclinical atherosclerosis increased with age, and was higher in males than females, with gender-specific differences in associated risk factors. These results will better inform individualised future risk management strategies to prevent the development and progression of coronary artery disease within healthy individuals.
Implementation and clinical outcomes of pharmacogenetic CYP2C19 testing for clopidogrel therapy in real-world clinical practice.
Authors: O"drisceoil POD , Kiernan TK , Arnous SA
Published: May 2021

Funding Acknowledgements

Type of funding sources: None.

BACKGROUNDCYP2C19 loss-of-function (LOF) polymorphisms are associated with adverse ischaemic events after PCI. The use of a point-of-care assay (POC) to routinely genotype patients immediately post PCI could rapidly identify patients at risk of adverse cardiac outcomes. PURPOSE To investigate the incidence of CYP2C19 polymorphisms (*2, *17) and 30-day MACE in patients presenting to catheter laboratory for PCI (See table 1).METHODS We performed a single centre prospective analysis of patients presenting to a cardiac catheterisation laboratory for percutaneous coronary intervention. Participants underwent prospective rapid point-of-care genotyping of CYP2C19 major alleles (2*,17*), using the SpartanRx PCR device via buccal swab sample. All patients provided written consent. RESULTS:A total of 120 tests were performed, 51 patients were normal allele carriers (*1), 31 patients were carriers of LOF alleles (*2) and 38 patients were carriers of gain of function alleles (*17). All tests results returned in one hour. Rate of dyslipidaemia was significantly different between three groups (55% vs. 63% vs. 36%; p = 0.050). A numerically higher proportion of LOF allele carriers received clopidogrel prior to undergoing pharmacogenetic testing but this was not statistically significant (52% vs. 35% vs. 34%; p = 0.09). Two cases of MACE at 30 day follow up occurred in the loss-of-function group. Both cases received clopidogrel.CONCLUSIONSWe have demonstrated that a rapid POC of CYP2C19 testing can take place in a real-world setting. Our incidence rate of LOF carriers is concordant with international published literature. We found 52% of LOF carriers were commenced on clopidogrel therapy prior to genetic analysis.

Comparison of CPY2C19 Metabolisers genotype Loss of function normal Gain of function p values baseline characteristics age in years, median (range) 65 (43-82) 64 (43-85) 65 (42-89) 0.717 Male, N (%) 21 (68%) 43 (64%) 27 (71%) 0.198 Hypertensive, N (%) 16 (52%) 29 (57%) 24 (50%) 0.623 Dyslipidaemia. N (%) 17 (55%) 32 (63%) 14 (36%) 0.050 Indication, N (%) St-Elevation MI 12 (39%) 18 (35%) 11 (29%) 0.558 NSTEMI 5 (16%) 15 (29%) 14 (37%) 0.142 Unstable Angina 5 (16%) 7 (14%) 3 (8%) 0.518 Stable CAD 9 (29%) 11 (22%) 10 (26%) 0.731 Antiplatelet, N (%) Ticagrelor 15 (48%) 33 (65%) 25 (66%) 0.09 Clopidogrel 16 (52%) 18 (35%) 13 (34%) Complication, N (%) 30-day MACE 2 (6.5%) 0 0 0.01
E-Cigarettes and myocardial Infarction: a systemic review and meta-analysis
Authors: Sharma A , Gupta I , U V , Golamari R
Published: May 2021

Funding Acknowledgements

Type of funding sources: None.

Introduction

With widespread awareness about the harmful effects of traditional smoking, many people are considering the use of an e-cigarette. However, there are many studies which have shown  e-cigarettes is not entirely harmless and it’s use has been implication in causing major adverse cardiovascular events.

Methodology

This systemic review strictly adhered to the PRISMA checklist. An electronic search was conducted comprehensively through five databases to find the relevant articles. The odds ratio (OR) was used for comparing groups. Meta-analysis was conducted using R statistical software version 3.4.3. A random-effect model was used.

Results

A total of 4 studies were included in the analysis incorporating data on 585,306 subjects. In these, 19,435 were e-cigarettes users, while 1693 used only traditional cigarette users, and 553,095 were non-e-cigarette users. A total of 7.0% of e-cigarette users suffered an MI in their lifetime, while only 6.5% of non-e-cigarette users have had MI. The OR of getting an MI in e-cigarettes users was 1.30 (95% CI = 1.23-1.38, p-value < 0.01) in comparison to non e-cigarette users. While it is 0.61 (95% CI = 0.40 – 0.93, p-value 0.02) when compared with traditional smoking.

Conclusion

Those using e-cigarettes have a higher odds of suffering from an MI in comparison to not using e-cigarettes. However, using e-cigarettes reduces the risk of MI by half in comparison to traditional smoking.

Abstract Figure. Forest plot