bluuebunny/crossref_metadata_2025 huggingface dataset:
Slip band formation in low and high solute aluminum: a combined experimental and modeling study
Authors: Prakash Aditya , Tak Tawqeer Nasir , Pai Namit N , Murty S V S Narayana , Guruprasad P J , Doherty R D , Samajdar Indradev
Published: October 2021

Direct ex situ observations related slip band formation with deformed microstructures in commercial AA1050 and AA2219. The samples from both grades had similar grain sizes (∼250 μm) and nearly random crystallographic textures. However, AA2219 contained significantly more solute. Slip bands, on the internal long transverse (LT) plane in split channel die specimens, were characterized by primary spacings (λ) of 2–9 μm, heights (Z) of 160–360 nm and secondary shear strains (

γ

LT

S

). Higher deformation temperatures for both grades increased λ, decreased, Z and

r
e
d
u
c
e
d

γ

LT

S

. At all deformation temperatures, AA1050 had smaller λ and higher Z, while AA2219 showed higher

γ

LT

S

. In-grain misorientations, but not residual strains, were larger in grains with finer λ in AA1050, but less so in AA2219. Discrete dislocation dynamics (DDD) simulations reported realistic slip bands with slip localizations. The simulations, initiated with static obstacles and sources, led to dislocation interactions and junction formation. The probability of junction stabilization (p) determined the ratio of dynamic sources to obstacles. Slip band formation appeared to be an outcome of the release of piled up dislocations leading to dislocation avalanches. Slip localization increased weakly with finer active slip plane spacing (λ
*), giving higher dynamic obstacle strengths and densities, but strongly with smaller p. In particular, the DDD simulations captured experimental patterns of higher slip localizations and dislocation densities in low solute aluminum with finer λ
*.
Construction of 3D CrN@nitrogen-doped carbon nanosheet arrays by reactive magnetron sputtering for the free-standing electrode of supercapacitor
Authors: Xu Xun , Chang Songyang , Hong Zhuozheng , Zeng Ye , Zhang Hao , Li Ping , Zheng Shizheng , Wang Zhoucheng , Duo Shuwang
Published: October 2021

Owing to their favorable chemical stabilities and electronic conductivities, transition metal nitrides (TMNs) have been targeted as the potential electrode materials for the supercapacitors. Herein, 3D CrN@nitrogen-doped carbon nanosheet arrays (NCs) were successfully deposited on carbon paper (CP) by reactive magnetron sputtering method. The CrN@NCs@CP electrode exhibited satisfactory electrochemical properties: initially, the electrode showed a 132.1 mF cm−2 specific capacitance at 1.0 mA cm−2 current density; subsequently, the electrode demonstrated a 95.9% capacitance retention after 20 000 galvanostatic charge–discharge cycles at 5.0 mA cm−2 current density. The specific capacitance of the CrN@NCs@CP electrode was significantly higher than that of the CrN@CP electrode (4.1 mF cm−2 at 1.0 mA cm−2). Furthermore, the symmetric supercapacitor that incorporated two CrN@NCs@CP electrodes demonstrated 5.28 μWh cm−2 (2.7 Wh kg−1) energy density at 0.41 mW cm−2 power density. These findings exemplify the suitability of the 3D composite electrodes of TMNs for energy storage application.
Visualization of a hexagonal boron nitride monolayer on an ultra-thin gold film via reflected light microscopy
Authors: Hattori Yoshiaki , Taniguchi Takashi , Watanabe Kenji , Kitamura Masatoshi
Published: October 2021

Hexagonal boron nitride (h-BN) is an important insulating layered material for two-dimensional heterostructure devices. Among many applications, few-layer h-BN films have been employed as superior tunneling barrier films. However, it is difficult to construct a heterostructure with ultra-thin h-BN owing to the poor visibility of flakes on substrates, especially on a metallic surface substrate. Since reflectance from a metallic surface is generally high, a h-BN film on a metallic surface does not largely influence reflection spectra. In the present study, a thin Au layer with a thickness of ∼10 nm deposited on a Si substrate with a thermally grown SiO2 was used for visualizing h-BN flakes. The thin Au layer possesses conductivity and transparency. Thus, the Au/SiO2/Si structure serves as an electrode and contributes to the visualization of an ultra-thin film according to optical interference. As a demonstration, the wavelength-dependent contrast of exfoliated few-layer h-BN flakes on the substrate was investigated under a quasi-monochromatic light using an optical microscope. A monolayer h-BN film was recognized in the image taken by a standard digital camera using a narrow band-pass filter of 490 nm, providing maximum contrast. Since the contrast increases linearly with the number of layers, the appropriate number of layers is identified from the contrast. Furthermore, the insulating property of a h-BN flake is examined using a conductive atomic force microscope to confirm whether the thin Au layer serves as an electrode. The tunneling current through the h-BN flake is consistent with the number of layers estimated from the contrast.
Cytocompatibility of carboxylated multi-wall carbon nanotubes in stem cells from human exfoliated deciduous teeth
Authors: Oliveira Eduarda R , Fayer Leonara , Zanette Rafaella S S , Ladeira Luiz O , de Oliveira Luiz F C , Maranduba Carlos M C , Brandão Humberto M , Munk Michele
Published: October 2021

Carboxylated multi-wall carbon nanotube (MWCNT-COOH) presents unique properties due to nanoscale dimensions and permits a broad range of applications in different fields, such as bone tissue engineering and regenerative medicine. However, the cytocompatibility of MWCNT-COOH with human stem cells is poorly understood. Thus, studies elucidating how MWCNT-COOH affects human stem cell viability are essential to a safer application of nanotechnologies. Using stem cells from the human exfoliated deciduous teeth model, we have evaluated the effects of MWCNT-COOH on cell viability, oxidative cell stress, and DNA integrity. Results demonstrated that despite the decreased metabolism of mitochondria, MWCNT-COOH had no toxicity against stem cells. Cells maintained viability after MWCNT-COOH exposure. MWCNT-COOH did not alter the superoxide dismutase activity and did not cause genotoxic effects. The present findings are relevant to the potential application of MWCNT-COOH in the tissue engineering and regenerative medicine fields.
Absence of absolutely continuous diffraction spectrum for certain S-adic tilings
Authors: Nagai Yasushi
Published: October 2021

Quasiperiodic tilings are often considered as structure models of quasicrystals. In this context, it is important to study the nature of the diffraction measures for tilings. In this article, we investigate the diffraction measures for S-adic tilings in

R

d

, which are constructed from a family of geometric substitution rules. In particular, we firstly give a sufficient condition for the absolutely continuous component of the diffraction measure for an S-adic tiling to be zero. Next, we prove this sufficient condition for ‘almost all’ binary block-substitution cases and thus prove the absence of the absolutely continuous diffraction spectrum for most of S-adic tilings from a family of binary block substitutions.
Well-posedness and global dynamics for the critical Hardy–Sobolev parabolic equation
Authors: Chikami Noboru , Ikeda Masahiro , Taniguchi Koichi
Published: October 2021

We study the Cauchy problem for the semilinear heat equation with the singular potential, called the Hardy–Sobolev parabolic equation, in the energy space. The aim of this paper is to determine a necessary and sufficient condition on initial data below or at the ground state, under which the behavior of solutions is completely dichotomized. More precisely, the solution exists globally in time and its energy decays to zero in time, or it blows up in finite or infinite time. The result on the dichotomy for the corresponding Dirichlet problem is also shown as a by-product via comparison principle.
A deep-learning method for generating synthetic kV-CT and improving tumor segmentation for helical tomotherapy of nasopharyngeal carcinoma
Authors: Chen Xinyuan , Yang Bining , Li Jingwen , Zhu Ji , Ma Xiangyu , Chen Deqi , Hu Zhihui , Men Kuo , Dai Jianrong
Published: October 2021

Objective: Megavoltage computed tomography (MV-CT) is used for setup verification and adaptive radiotherapy in tomotherapy. However, its low contrast and high noise lead to poor image quality. This study aimed to develop a deep-learning-based method to generate synthetic kilovoltage CT (skV-CT) and then evaluate its ability to improve image quality and tumor segmentation. Approach: The planning kV-CT and MV-CT images of 270 patients with nasopharyngeal carcinoma (NPC) treated on an Accuray TomoHD system were used. An improved cycle-consistent adversarial network which used residual blocks as its generator was adopted to learn the mapping between MV-CT and kV-CT and then generate skV-CT from MV-CT. A Catphan 700 phantom and 30 patients with NPC were used to evaluate image quality. The quantitative indices included contrast-to-noise ratio (CNR), uniformity and signal-to-noise ratio (SNR) for the phantom and the structural similarity index measure (SSIM), mean absolute error (MAE), and peak signal-to-noise ratio (PSNR) for patients. Next, we trained three models for segmentation of the clinical target volume (CTV): MV-CT, skV-CT, and MV-CT combined with skV-CT. The segmentation accuracy was compared with indices of the dice similarity coefficient (DSC) and mean distance agreement (MDA). Main
results: Compared with MV-CT, skV-CT showed significant improvement in CNR (184.0%), image uniformity (34.7%), and SNR (199.0%) in the phantom study and improved SSIM (1.7%), MAE (24.7%), and PSNR (7.5%) in the patient study. For CTV segmentation with only MV-CT, only skV-CT, and MV-CT combined with skV-CT, the DSCs were 0.75 ± 0.04, 0.78 ± 0.04, and 0.79 ± 0.03, respectively, and the MDAs (in mm) were 3.69 ± 0.81, 3.14 ± 0.80, and 2.90 ± 0.62, respectively. Significance: The proposed method improved the image quality of MV-CT and thus tumor segmentation in helical tomotherapy. The method potentially can benefit adaptive radiotherapy.
Out-of-field dose and its constituent components for a 1.5 T MR-Linac
Authors: Yang Bin , Tang Ka Keung , Huang Chen-Yu , Geng Hui , Lam Wai Wang , Wong Yeung Sum , Tse Mei Yan , Lau Ka Ki , Cheung Kin Yin , Yu Siu Ki
Published: October 2021

This study aims to quantify the relative contributions of phantom scatter, collimator scatter and head leakage to the out-of-field doses (OFDs) of both static fields and clinical intensity-modulated radiation therapy (IMRT) treatments in a 1.5 T MR-Linac. The OFDs of static fields were measured at increasing distances from the field edge in an MR-conditional water phantom. Inline scans at depths of dmax (14 mm), 50 and 100 mm were performed for static fields of 5 × 5, 10 × 10 and 15 × 15 cm2 under three different conditions: full scatter, with phantom scatter prevented, and head leakage only. Crossline scans at isocenter and offset positions were performed in full scatter condition. EBT3 radiochromic films were placed at 100 mm depth of solid water phantom to measure the OFD of clinical IMRT plans. All water tank data were normalized to Dmax of a 10 × 10 cm2 field and the film results were presented as a fraction of the target mean dose. The OFD in the inline direction varied from 3.5% (15 × 15 cm2, 100 mm depth, 50 mm distance) to 0.014% (5 × 5 cm2, dmax, 400 mm distance). For all static fields, the collimator scatter was higher than the phantom scatter and head leakage at a distance of 100–400 mm. Head leakage remained the smallest among the three components, except at long distances (>375 mm) with small field size. Compared to the inline scans, the crossline scans at the isocenter showed higher doses at distances longer than 80 mm. All crossline profiles at longitudinal offset positions showed a cone shape with laterally shifted maxima. The OFD of IMRT deliveries varied with different target size. For prostate stereotactic body radiation therapy (SBRT) treatment, the OFD decreased from 2% to 0.03% at a distance of 50–500 mm. The OFDs have been measured for a 1.5 T MR-Linac. The presented dosimetric data are valuable for radiation safety assessments on patients treated with the MR-Linac, such as evaluating carcinogenic risk and radiation exposure to cardiac implantable electronic devices.
Temporal studies of titanium ionised density fraction in reactive HiPIMS with nitrogen admixture
Authors: Bernátová K , Klein P , Hnilica J , Vašina P
Published: October 2021

Temporal evolutions of the ground state number densities of titanium atoms and ions and the ionised density fraction during pulse on-time are experimentally investigated for the high-power impulse magnetron sputtering process in an Ar and Ar/N2 atmosphere. For the study, two distinct pulses with the same pulse length at a constant average power but different pulse off-times were selected. In both conditions, four representative points within the hysteresis curve were chosen, and the time evolutions of sputtered species densities were investigated in both the target and the substrate regions. At the pulse beginning, a high density of residual particles sputtered during the previous pulse is present in both studied regions. In the target region, in conditions of longer pulse off-time and thus higher peak discharge current, 95% of sputtered particles are ionised in metallic, transition and compound regimes. With shorter pulse off-time conditions, and thus a lower peak discharge current, the ionised density fraction is the lowest in the metallic regime; in the transition and compound regimes, it exceeds 80%. In the substrate region, the temporal evolution of sputtered species densities differs from that obtained in the target region. After the pulse ignition, titanium atoms and ions remaining near the substrate from the previous pulse are pushed away. In the metallic regime, the sputtered atoms refill the substrate region already during the pulse on-time in both the low- and high-current conditions. In the high-current conditions, the titanium ions arrive at the substrate together with the sputtered atoms; however, in the low-current conditions, the titanium ion density decreases during the pulse on-time, and the titanium ions arrive later during the pulse off-time. In the transition and compound regimes, both densities steadily decrease during the pulse on-time and the titanium atoms and ions arrive at the substrate during the pulse off-time.
Benefits of using arrays of vertical nanowire FETs in integrated circuits to mitigate variability
Authors: del Moral A , Amat E , Bausells J , Perez-Murano F
Published: October 2021

We investigate the benefits of the use of arrays of vertical nanowire (vNW) field-effect transistors (FETs) to implement integrated circuits. By means of technology computer aided design and circuit simulations, the optimal dimensions of the vNWFETs are determined. Device and circuit variability levels have been investigated. The benefits of using array configurations are the decrease of the response time and a significant mitigation of the variability level as the number of the elements in the array increases.
Study of traps in low-temperature polysilicon thin film transistors using a current transient method
Authors: Zhu Hui , Xie Na , Wang Si , Huang Zeng , Fang Zhixuan , Liu Zheng , Li Dong , Feng Shiwei , Guo Chunsheng , Zhang Yamin , Zhou Lixing , Liu Bo
Published: October 2021

The trap characteristics of low-temperature polysilicon thin film transistors (TFTs) are studied using a current transient method that is based on the trapping and detrapping of charge carriers from the trap sites in the device. Analysis of the measured current transient curve allowed three types of detrapping behavior to be identified, each of which displayed a different time constant, activation energy, and spatial position. This current transient method can be integrated into the negative bias temperature instability stress test used for the reliability study. The peak amplitudes of the traps increase because of the stress applied in the test, thus demonstrating that the degradation mechanism of the TFTs is closely related to changes in the traps in these devices.
A reconstructed three-dimensional HTS bulk electromagnetic model considering J
c spatial inhomogeneity and its implementation in a bulks’ combination system
Authors: Cheng Yanxing , Zheng Jun , Huang Huan , Deng Zigang
Published: October 2021

High-temperature superconducting (HTS) bulks in HTS Maglev systems are always arrayed in a combination to make full use of the applied magnetic field of the permanent magnet guideway (PMG). An excellent combination scheme improves the overall levitation and guidance performance significantly. In this paper, a three-dimensional (3D) electromagnetic model of the real HTS-PMG maglev system with an HTS bulk array was established. This model comprehensively expresses the influence of various factors on the
E
–
J
relationship and the 3D spatial distribution of J
c, including internal factors such as the inhomogeneity and anisotropy of electromagnetic characteristics, as well as external factors such as applied magnetic field and working temperature. A ternary function was proposed to describe the uneven distribution of J
c caused by the bulk’s growth process, which is an interesting phenomenological modeling attempt. In the simulations of the bulks’ combinations, perfect magnetic conductor boundary conditions were applied on the contact surface to simulate two bulks touching each other. Besides, the research target includes reproducing the shapes, the orientations, and the combination scheme of HTS bulks in the real PMG magnetic field. The calculation results of levitation force of the cylindrical bulk under different spatial orientations above the PMG were compared with the experimental results, through which the accuracy of the model was verified. On this basis, the influence of the magnetic field generated by the superconducting current on the nearby bulk was further explored. It was found that this magnetic field has a small contribution to the total levitation force and a relatively obvious influence on the guidance force. When the lateral displacement is large, such as 5 mm, the magnetic field generated by the superconducting current slightly increases the total guidance force stiffness. According to more simulated conditions, some optimization strategies on bulk combinations were proposed. This work provides not only a 3D descriptive model for fitting the real multi-bulk-combination maglev scenarios but also some optimization strategies for the HTS maglev transportation applications.
Influence of Hall effect and toroidal flow on the plasmoid formation and incomplete reconnection in a low resistivity plasma in tokamak
Authors: Zhang W. , Ma Z.W. , Zhang H.W.
Published: October 2021

The nonlinear resistive-kink mode in the low resistivity plasma in tokamak is investigated through the three-dimensional, toroidal, and nonlinear Hall-MHD code CLT. It is found that, without the two-fluid effect and the toroidal flow, the system can evolve into a steady-state with the saturated main m/n = 1/1 magnetic island and the co-existing large secondary island. The main m/n = 1/1 magnetic island cannot push the hot core plasma out of the q = 1 surface as it does in Kadomstev’s model, and the reconnection is incomplete. However, with the two-fluid effect or the toroidal flow, the nonlinear behaviors of the resistive-kink mode could be essentially different. The two-fluid effect and the toroidal flow can break the symmetry during the plasmoid formation, which destroys the balance between the main m/n = 1/1 magnetic island and the large secondary island. The large secondary island is then merged into the main m/n = 1/1 island. After that, the main m/n = 1/1 island finally occupies the whole mix region, and all magnetic flux in the mix region is reconnected. A similar simulation study has been done in periodic cylindrical geometry (Günter et al 2015 Plasma Phys. Control. Fusion
57 014017), while our work is done in tokamak toroidal geometry. The toroidal effect has also been investigated, and we find that the widths of the main 1/1 island and the secondary island slightly increase with increasing aspect ratios.
Asymptotic reversibility of thermal operations for interacting quantum spin systems via generalized quantum Stein’s lemma
Authors: Sagawa Takahiro , Faist Philippe , Kato Kohtaro , Matsumoto Keiji , Nagaoka Hiroshi , Brandão Fernando G S L
Published: October 2021

For quantum spin systems in any spatial dimension with a local, translation-invariant Hamiltonian, we prove that asymptotic state convertibility from a quantum state to another one by a thermodynamically feasible class of quantum dynamics, called thermal operations, is completely characterized by the Kullback–Leibler (KL) divergence rate, if the state is translation-invariant and spatially ergodic. Our proof consists of two parts and is phrased in terms of a branch of the quantum information theory called the resource theory. First, we prove that any states, for which the min and max Rényi divergences collapse approximately to a single value, can be approximately reversibly converted into one another by thermal operations with the aid of a small source of quantum coherence. Second, we prove that these divergences collapse asymptotically to the KL divergence rate for any translation-invariant ergodic state. We show this via a generalization of the quantum Stein’s lemma for quantum hypothesis testing beyond independent and identically distributed situations. Our result implies that the KL divergence rate serves as a thermodynamic potential that provides a complete characterization of thermodynamic convertibility of ergodic states of quantum many-body systems in the thermodynamic limit, including out-of-equilibrium and fully quantum situations.
Manipulation of spin transport in graphene/transition metal dichalcogenide heterobilayers upon twisting
Authors: Pezo Armando , Zanolli Zeila , Wittemeier Nils , Ordejón Pablo , Fazzio Adalberto , Roche Stephan , Garcia Jose H
Published: October 2021

Proximity effects between layered materials trigger a plethora of novel and exotic quantum transport phenomena. Besides, the capability to modulate the nature and strength of proximity effects by changing crystalline and interfacial symmetries offers a vast playground to optimize physical properties of relevance for innovative applications. In this work, we use large-scale first principles calculations to demonstrate that strain and twist-angle strongly vary the spin–orbit coupling (SOC) in graphene/transition metal dichalcogenide heterobilayers. Such a change results in a modulation of the spin relaxation times by up to two orders of magnitude. Additionally, the relative strengths of valley-Zeeman and Rashba SOC can be tailored upon twisting, which can turn the system into an ideal Dirac–Rashba regime or generate transitions between topological states of matter. These results shed new light on the debated variability of SOC and clarify how lattice deformations can be used as a knob to control spin transport. Our outcomes also suggest complex spin transport in polycrystalline materials, due to the random variation of grain orientation, which could reflect in large spatial fluctuations of SOC fields.
Numerical simulation and experimental research on an inductively coupled RF plasma cathode
Authors: XU Zongqi , WANG Pingyang , HUA Zhiwei , CONG Shiyuan , YU Shengnan
Published: October 2021

In this study, numerical simulation and discharge current tests were conducted on an inductively coupled radio frequency (RF) plasma cathode. Numerical simulations and experimental measurements were performed to study the factors influencing the electron extraction characteristics, including the gas type, gas flow, input power and extracting voltage. The simulation results were approximately consistent with the experimental results. We experimentally found that the RF input power mainly determines the extracted electron current. An electron current greater than 1 A was acquired at 270 W (RF input power), 2.766 sccm (xenon gas). Our results prove that an inductively coupled RF plasma cathode can be reasonable and feasible, particularly for low power electric propulsion devices.
Analytical application of H
2
O
2
-induced chiroptical graphitic carbon dots
Authors: Das Smita , Gogoi Sudarshan , Singh Naveen Kumar , Goswami Pranab
Published: October 2021

Carbon dots (CDs) have emerged as efficient peroxidase mimics in recent years. However, to further increase its efficiency as peroxidase-mimic, it is also desirable to understand the modification of CD’s geometry during the catalytic reaction. Herein, we focused on the change in material property of the CDs upon their reaction with H2O2 during the peroxidase reaction. D-(+)-glucose was transformed into chiroptical CDs bearing peroxidase-like activity and can be used to detect H2O2 with a limit of detection of 630 μM. The addition of H2O2 to the CDs resulted in its increased molecular orderliness leading to the introduction of polycrystallinity without affecting its peroxidase-like activity.
Invited Commentary: Comparing Approaches to Measuring Structural Racism
Authors: Jahn Jaquelyn L
Published: October 2021

In their article, Adkins-Jackson et al. (Am J Epidemiol. 2022;191(4):539–547) provide much needed insight on current approaches and challenges to epidemiologic research on structural racism. The authors encourage researchers to consider how structural racism is conceptualized in extant and future work, and whether existing measures accurately reflect the multidimensional nature of structural racism. In the spirit of continuing this conversation, I expand upon approaches to measuring structural racism. I compare the merits and challenges of scales, indexes, indicators, and policy-based measures of structural racism for use in epidemiologic research.
Effects of Antihypertensive Deprescribing Strategies on Blood Pressure, Adverse Events, and Orthostatic Symptoms in Older Adults: Results From TONE
Authors: Juraschek Stephen P , Cluett Jennifer L , Belanger Matthew J , Anderson Timothy S , Ishak Anthony , Sahni Shivani , Millar Courtney , Appel Lawrence J , Miller Edgar R , Lipsitz Lewis A , Mukamal Kenneth J
Published: October 2021

Background

The Trial of Nonpharmacologic Interventions in the Elderly (TONE) demonstrated the efficacy of weight loss and sodium reduction to reduce hypertension medication use in older adults. However, the longer-term effects of drug withdrawal (DW) on blood pressure (BP), adverse events, and orthostatic symptoms were not reported.

Methods

TONE enrolled adults, ages 60–80 years, receiving treatment with a single antihypertensive and systolic BP (SBP)/diastolic BP <145/<85 mm Hg. Participants were randomized to weight loss, sodium reduction, both, or neither (usual care) and followed up to 36 months; ~3 months postrandomization, the antihypertensive was withdrawn and only restored if needed for uncontrolled hypertension. BP and orthostatic symptoms (lightheadedness, feeling faint, imbalance) were assessed at randomization and throughout the study. Two physicians independently adjudicated adverse events, masked to intervention, classifying symptomatic (lightheadedness, dizziness, vertigo), or clinical events (fall, fracture, syncope).

Results

Among the 975 participants (mean age 66 years, 48% women, 24% black), mean (±SD) BP was 128 ± 9/71 ± 7 mm Hg. Independent of assignment, DW increased SBP by 4.59 mm Hg (95% confidence interval [CI]: 3.89, 5.28) compared with baseline. There were 113 adverse events (84 symptomatic, 29 clinical), primarily during DW. Compared with usual care, combined weight loss and sodium reduction mitigated the effects of DW on BP (β = −4.33 mm Hg; 95% CI: −6.48, −2.17) and reduced orthostatic symptoms long term (odds ratio = 0.62; 95% CI: 0.41, 0.92), without affecting adverse events (hazard ratio = 1.81; 95% CI: 0.90, 3.65). In contrast, sodium reduction alone increased risk of adverse events (hazard ratio = 1.75; 95% CI: 1.04, 2.95), mainly during DW.

Conclusions

In older adults, antihypertensive DW may increase risk of symptomatic adverse events, highlighting the need for caution in withdrawing their antihypertensive medications.

Clinical trials registration

Trial Number NCT00000535.
Predictors of failure to reach target sample size in surgical randomized trials
Authors: Chadow David , Robinson N Bryce , Cancelli Gianmarco , Soletti Giovanni , Audisio Katia , Rahouma Mohamed , Perezgrovas Roberto , Gaudino Mario
Published: October 2021

It is estimated that 25–30 per cent of RCTs fail to reach their target sample size. Multicentre design, publication year, and commercial sponsor were inversely associated with failure to reach the target sample size. A substantial proportion of surgical trials fail reach target sample size, but the trend is showing improvement.
Use of data sets collected by surgical collaborating groups
Authors: Gaardsted Pernille Skou , Laursen Henrik Sehested , Poulsen Simon Hosbond , Krzyslak Hubert , El-Hussuna Alaa ,   the OpenSourceResearch Collaboration
Published: October 2021

The use of data sets collected by collaborative groups might be limited. There is a need to improve harmonization of data collection and data sharing to allow pooling of data.
Cognitive task analysis-based training in surgery: a meta-analysis
Authors: Edwards Thomas C , Coombs Alexander W , Szyszka Bartosz , Logishetty Kartik , Cobb Justin P
Published: October 2021

Background

Reduced hands-on operating experience has challenged the development of complex decision-making skills for modern surgical trainees. Cognitive task analysis- (CTA-)based training is a methodical solution to extract the intricate cognitive processes of experts and impart this information to novices. Its use has been successful in high-risk industries such as the military and aviation, though its application for learning surgery is more recent. This systematic review aims to synthesize the evidence evaluating the efficacy of CTA-based training to enable surgeons to acquire procedural skills and knowledge.

Methods

The PRISMA guidelines were followed. Four databases, including MEDLINE, EMBASE, Web of Science and Cochrane CENTRAL, were searched from inception to February 2021. Randomized controlled trials and observational studies evaluating the training effect of CTA-based interventions on novices' procedural knowledge or technical performance were included. Meta-analyses were performed using a random-effects model.

Results

The initial search yielded 2205 articles, with 12 meeting the full inclusion criteria. Seven studies used surgical trainees as study subjects, four used medical students and one study used a combination. Surgical trainees enrolled into CTA-based training groups had enhanced procedural knowledge (standardized mean difference (SMD) 1.36 (95 per cent c.i. 0.67 to 2.05), P < 0.001) and superior technical performance (SMD 2.06 (95 per cent c.i. 1.17 to 2.96), P < 0.001) in comparison with groups that used conventional training methods.

Conclusion

CTA-based training is an effective way to learn the cognitive skills of a surgical procedure, making it a useful adjunct to current surgical training.
Tocilizumab suppresses the pro-carcinogenic effects of breast cancer-associated fibroblasts through inhibition of the STAT3/AUF1 pathway
Authors: Al-Jomah Naif , Al-Mohanna Falah H , Aboussekhra Abdelilah
Published: October 2021

Active breast cancer-associated fibroblasts (CAFs), the most influential cells in breast tumor microenvironment, express/secrete high levels of the proinvasive/metastatic interleukin-6 (IL-6). Therefore, we have tested here the effect of the IL-6 receptor (IL-6R) inhibitor tocilizumab (TCZ; Actemra) on different active breast CAFs. We have shown that TCZ potently and persistently suppresses the expression of various CAF biomarkers, namely α-SMA, SDF-1 as well as the STAT3 pathway and its downstream target AUF1. TCZ also inhibited the proliferation, migration and invasion abilities of active breast CAF cells. Additionally, TCZ repressed the ability of CAF cells in promoting epithelial-to-mesenchymal transition, and enhancing the migratory/invasive and proliferative capacities of breast cancer cells in vitro. Importantly, these findings were confirmed in orthotopic humanized breast tumors in mice. Furthermore, TCZ suppressed the expression of the pro-angiogenic factor VEGF-A and its transactivator HIF-1α in CAF cells, and consequently inhibited the angiogenic-promoting effect of active CAFs both in vitro and in orthotopic tumor xenografts. These results indicate that inhibition of the IL-6/STAT3/AUF1 pathway by TCZ can normalize active breast CAFs and suppress their paracrine pro-carcinogenic effects, which paves the way toward development of specific CAF-targeting therapy, badly needed for more efficient breast cancer treatments.
Functional assessment of somatic STK11 variants identified in primary human non-small cell lung cancers
Authors: Donnelly Liam L , Hogan Tyler C , Lenahan Sean M , Nandagopal Gopika , Eaton Jenna G , Lebeau Meagan A , McCann Cai L , Sarausky Hailey M , Hampel Kenneth J , Armstrong Jordan D , Cameron Margaret P , Sidiropoulos Nikoletta , Deming Paula , Seward David J
Published: October 2021

Serine/Threonine Kinase 11 (STK11) encodes an important tumor suppressor that is frequently mutated in lung adenocarcinoma. Clinical studies have shown that mutations in STK11 resulting in loss of function correlate with resistance to anti-PD-1 monoclonal antibody therapy in KRAS-driven non-small cell lung cancer (NSCLC), but the molecular mechanisms responsible remain unclear. Despite this uncertainty, STK11 functional status is emerging as a reliable biomarker for predicting non-response to anti-PD-1 therapy in NSCLC patients. The clinical utility of this biomarker ultimately depends upon accurate classification of STK11 variants. For nonsense variants occurring early in the STK11 coding region, this assessment is straightforward. However, rigorously demonstrating the functional impact of missense variants remains an unmet challenge. Here we present data characterizing four STK11 splice-site variants by analyzing tumor mRNA, and 28 STK11 missense variants using an in vitro kinase assay combined with a cell-based p53-dependent luciferase reporter assay. The variants we report were identified in primary human NSCLC biopsies in collaboration with the University of Vermont Genomic Medicine group. Additionally, we compare our experimental results with data from 22 in silico predictive algorithms. Our work highlights the power, utility and necessity of functional variant assessment and will aid STK11 variant curation, provide a platform to assess novel STK11 variants and help guide anti-PD-1 therapy utilization in KRAS-driven NSCLCs.
The stability of tastant detection by mouse lingual chemosensory tissue requires Regulator of G protein Signaling-21 (RGS21)
Authors: Schroer Adam B , Branyan Kayla W , Gross Joshua D , Chantler Paul D , Kimple Adam J , Vandenbeuch Aurelie , Siderovski David P
Published: October 2021

The T1R and T2R families of G protein-coupled receptors (GPCRs) initiate tastant perception by signaling via guanine nucleotide exchange and hydrolysis performed by associated heterotrimeric G proteins (Gαβγ). Heterotrimeric G protein signal termination is sped up by Gα-directed GTPase-accelerating proteins (GAPs) known as the Regulators of G protein Signaling (RGS proteins). Of this family, RGS21 is highly expressed in lingual epithelial cells and we have shown it acting in vitro to decrease the potency of bitterants on cultured cells. However, constitutive RGS21 loss in mice reduces organismal response to GPCR-mediated tastants—opposite to expectations arising from observed in vitro activity of RGS21 as a GAP and inhibitor of T2R signaling. Here, we show reduced quinine aversion and reduced sucrose preference by mice lacking RGS21 does not result from post-ingestive effects, as taste-salient brief-access tests confirm the reduced bitterant aversion and reduced sweetener preference seen using two-bottle choice testing. Eliminating Rgs21 expression after chemosensory system development, via tamoxifen-induced Cre recombination in eight week-old mice, led to a reduction in quinine aversive behavior that advanced over time, suggesting that RGS21 functions as a negative regulator to sustain stable bitter tastant reception. Consistent with this notion, we observed downregulation of multiple T2R proteins in the lingual tissue of Rgs21-deficient mice. Reduced tastant-mediated responses exhibited by mice lacking Rgs21 expression either since birth or in adulthood has highlighted the potential requirement for a GPCR GAP to maintain the full character of tastant signaling, likely at the level of mitigating receptor downregulation.
Effectiveness of BNT162b2 mRNA Coronavirus Disease 2019 (COVID-19) Vaccine Against Acquisition of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Among Healthcare Workers in Long-Term Care Facilities: A Prospective Cohort Study
Authors: Muhsen Khitam , Maimon Nimrod , Mizrahi Ami , Bodenheimer Omri , Cohen Dani , Maimon Michal , Grotto Itamar , Dagan Ron
Published: October 2021

Background

We assessed vaccine effectiveness (VE) of BNT162b2 mRNA coronavirus disease 2019 (COVID-19) vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) acquisition among healthcare workers (HCWs) of long-term care facilities (LTCFs).

Methods

This prospective study, in the framework of the “Senior Shield” program in Israel, included routine weekly nasopharyngeal SARS-CoV-2 RT-PCR testing from all LTCF HCWs since July 2020. All residents and 75% of HCWs were immunized between December 2020 and January 2021. The analysis was limited to HCWs adhering to routine testing. Fully vaccinated (14+ days after second dose; n = 6960) and unvaccinated (n = 2202) HCWs were simultaneously followed until SARS-CoV-2 acquisition or end of follow-up, 11 April 2021. Hazard ratios (HRs) for vaccination versus no vaccination were calculated (Cox proportional hazards regression models, adjusting for sociodemographics and residential-area COVID-19 incidence). VE was calculated as (1– HR) × 100. RT-PCR cycle threshold (Ct) values were compared between vaccinated and unvaccinated HCWs.

Results

At >14 days post–second dose, 40 vaccinated HCWs acquired SARS-CoV-2 (median follow-up, 66 days; cumulative incidence, 0.6%) versus 84 unvaccinated HCWs (median follow-up, 43 days; cumulative incidence, 5.1%) (HR, .11; 95% CI, .07–.17; unadjusted VE, 89%; 95% CI, 83–93%). Adjusted VE >7 and >14 days post–second dose were similar. The median PCR Ct targeting the ORF1ab gene among 20 vaccinated and 40 unvaccinated HCWs was 32.0 versus 26.7, respectively (P value  = .008).

Conclusions

VE following 2 doses of BNT162b2 against SARS-CoV-2 acquisition in LTCF HCWs was high. The lower viral loads among SARS-CoV-2–positive HCWs suggest further reduction in transmission.
Isolation of a Novel Recombinant Canine Coronavirus From a Visitor to Haiti: Further Evidence of Transmission of Coronaviruses of Zoonotic Origin to Humans
Authors: Lednicky John A , Tagliamonte Massimiliano S , White Sarah K , Blohm Gabriela M , Alam Md Mahbubul , Iovine Nicole M , Salemi Marco , Mavian Carla , Morris J Glenn
Published: October 2021

We isolated a novel coronavirus from a medical team member presenting with fever and malaise after travel to Haiti. The virus showed 99.4% similarity with a recombinant canine coronavirus recently identified in a pneumonia patient in Malaysia, suggesting that infection with this virus and/or recombinant variants occurs in multiple locations.
Performance Characteristics of a Clinical Decision Support Tool for Disease Complications in Crohn’s Disease
Authors: Siegel Corey A , Siegel Lori S , Dubinsky Marla C , Targan Stephan , Braun Jonathan , Landers Carol , Bilsborough Janine , Princen Fred , Lasch Karen , Candela Ninfa , McGovern Dermot P B , Dervieux Thierry
Published: October 2021

Background

Patients with Crohn’s disease (CD) are at risk of complications. Performance characteristics of a decision support tool assessing the risk of CD complications were evaluated.

Methods

CDPATH (formerly called the Personalized Risk and Outcome Prediction Tool [PROSPECT]) was calibrated and validated in 2 cohorts. Tool prediction of disease characteristics was assessed using Cox regression and Harrell’s C-statistic.

Results

All associations of CD complications and CDPATH components were significant except perianal location. There was a significant association between individualized risk assessment scores and CD complications in both cohorts.

Conclusion

CDPATH is validated as a clinical decision support tool for assessing the risk of CD complications.
At-C-RNA database, a one-stop source for information on circRNAs inArabidopsis thalianain a unified format
Authors: Nowis Katarzyna , Jackowiak Paulina , Figlerowicz Marek , Philips Anna
Published: October 2021

Circular RNAs (circRNAs) are a large class of noncoding RNAs with functions that, in most cases, remain unknown. Recent genome-wide analysis of circRNAs using RNA-Seq has revealed that circRNAs are abundant and some of them conserved in plants. Furthermore, it has been shown that the expression of circRNAs in plants is regulated in a tissue-specific manner. Arabidopsis thaliana circular RNA database is a new resource designed to integrate and standardize the data available for circRNAs in a model plant A. thaliana, which is currently the best-characterized plant in terms of circRNAs. The resource integrates all applicable publicly available RNA-seq datasets. These datasets were subjected to extensive reanalysis and curation, yielding results in a unified format. Moreover, all data were normalized according to our optimized approach developed for circRNA identification in plants. As a result, the database accommodates circRNAs identified across organs and seedlings of wild-type A. thaliana and its single-gene knockout mutants for genes related to splicing. The database provides free access to unified data and search functionalities, thus enabling comparative analyses of A. thaliana circRNAs between organs, variants and studies for the first time.

Database URLhttps://plantcircrna.ibch.poznan.pl/
Case report of a Gore-Tex TCPC conduit dissection causing severe stenosis
Authors: Bates Oliver , Semple Thomas , Krupickova Sylvia , Bautista-Rodriguez Carles
Published: October 2021

Background

The patient is a 15-year-old male with situs inversus, dextrocardia, bilateral superior caval veins, atrioventricular discordance with a single outlet, large perimembranous ventricular septal defect, aortic override, pulmonary atresia, and right aortic arch. The complex anatomy with a Ventricular Septal Defect (VSD) distant from the aorta (unsuitable for baffling to the aorta) meant he was unsuitable for biventricular repair and proceeded down a univentricular palliation pathway.

Case summary

Post-total cavopulmonary connection his clinical course was uneventful until the age of 5 when he developed fatigability with desaturation. An accessory hepatic vein was surgically banded with improved saturations and exercise tolerance. At the age of 15, cardiovascular magnetic resonance (CMR) was performed to investigate borderline saturations and as workup for transition to adult services. Cardiovascular magnetic resonance and cardiac computed tomography (CT) imaging demonstrated an eccentric thrombus causing stenosis of the extracardiac conduit and a thrombus outside of the lumen contained by the thin outer membrane of the Gore-Tex conduit. Collateralization suggested this was longstanding. Cardiac catheterization demonstrated a 4 mm × 6 mm stenosis at the junction of the conduit with the pulmonary arteries. The region was successfully balloon dilated and stented with a 34 mm-long Cheatham Platinum stent, with no complications.

Discussion

To date, this is the first documented case of a dissecting thrombus of a Gore-Tex graft in the literature. This case emphasizes the need for anticoagulation and serial cross-sectional imaging (CT or CMR) in Fontan patients with prosthetic grafts throughout a patients’ lifetime.
Importance of sex and gender in ischaemic stroke and carotid atherosclerotic disease
Authors: Gasbarrino Karina , Di Iorio Diana , Daskalopoulou Stella S
Published: October 2021

Stroke is a leading cause of death and disability worldwide. Women are disproportionately affected by stroke, exhibiting higher mortality and disability rates post-stroke than men. Clinical stroke research has historically included mostly men and studies were not properly designed to perform sex- and gender-based analyses, leading to under-appreciation of differences between men and women in stroke presentation, outcomes, and response to treatment. Reasons for these differences are likely multifactorial; some are due to gender-related factors (i.e. decreased social support, lack of stroke awareness), yet others result from biological differences between sexes. Unlike men, women often present with ‘atypical’ stroke symptoms. Lack of awareness of ‘atypical’ presentation has led to delays in hospital arrival, diagnosis, and treatment of women. Differences also extend to carotid atherosclerotic disease, a cause of stroke, where plaques isolated from women are undeniably different in morphology/composition compared to men. As a result, women may require different treatment than men, as evidenced by the fact that they derive less benefit from carotid revascularization than men but more benefit from medical management. Despite this, women are less likely than men to receive medical therapy for cardiovascular risk factor management. This review focuses on the importance of sex and gender in ischaemic stroke and carotid atherosclerotic disease, summarizing the current evidence with respect to (i) stroke incidence, mortality, awareness, and outcomes, (ii) carotid plaque prevalence, morphology and composition, and gene connectivity, (iii) the role of sex hormones and sex chromosomes in atherosclerosis and ischaemic stroke risk, and (iv) carotid disease management.
Trajectories of low back pain from midlife to retirement and functional ability at old age
Authors: Kyrönlahti Saila M , Nygård Clas-Håkan , K. C Prakash , Neupane Subas
Published: October 2021

Background

This study aimed to identify trajectories of low back pain (LBP) over a 16-year follow-up from midlife to retirement and investigate their association with mobility limitations and disability in activities of daily living (ADL-disability) in later life.

Methods

The study population consisted of 6257 baseline (1981) respondents aged 44–58 years from Finnish Longitudinal study on Aging Municipal Employees. Repeated measurements of LBP were collected in 1985, 1992 and 1997. We studied persons who had data on LBP at baseline and in at least one of the follow-ups and had information on mobility limitations (n = 2305) and ADL-disability (n = 2359) at a 28-year follow-up in 2009. Latent class growth analysis was used to identify LBP trajectories. Odds ratios (ORs) with 95% confidence intervals (CIs) for the associations of LBP trajectory and later life mobility limitations and ADL-disability were estimated and adjusted for confounders.

Results

Three LBP trajectories with parallel shapes were identified: high-decreasing (19%), intermediate-stable (60%) and low (21%). After adjustment for confounders, high-decreasing trajectory had 3.2 times the odds (95% CI 2.1–4.9) of mobility limitations and 2.9 times the odds (95% CI 2.0–4.2) of ADL-disability as compared to low trajectory. The respective ORs for intermediate-stable trajectory were 1.6 (95% CI 1.2–2.1) and 1.7 (95% CI 1.3–2.3).

Conclusions

Among majority of respondents, LBP remained stable over the follow-up. The respondents belonging to intermediate-stable and high-decreasing trajectories of LBP had higher odds of mobility limitations and ADL-disability at old age. This highlights that LBP during midlife to retirement has far-reached consequences on functional ability at old age.