bluuebunny/crossref_metadata_2025 huggingface dataset:
Preventive Care Utilization among Adults with Hearing Loss in the United States
Authors: Fioravante Nicholas , Deal Jennifer A. , Willink Amber , Myers Clarice , Assi Lama
Published: April 2021

Hearing loss (HL) can negatively impact patient–provider communication and limit access to health promotion information, which may lead to decreased preventive care utilization. Using data from the 2015 and 2018 National Health Interview Survey, we examined the association between perceived HL with and without hearing aid use with self-reported age-appropriate uptake of breast and colon cancer screening, and influenza and pneumococcal vaccination. In models adjusted for sociodemographic characteristics, access to care, and health status, people with HL had lower odds of receiving breast cancer screening (odds ratio [OR] = 0.83, 95% confidence interval [CI] = 0.72–0.96) and higher odds of receiving pneumococcal vaccination (OR = 1.11, 95% CI = 1.00–1.24) relative to those without HL. There were no differences in their colon cancer or influenza vaccination uptake. Compared with those without HL, people with HL who used hearing aids had increased odds of colon cancer screening and influenza and pneumococcal vaccination, while people with HL who did not use hearing aids were less likely to report cancer screening. Overall, Americans with untreated HL were less likely to report completing cancer screening. Hearing aid use may modify the association between HL and preventive care uptake. Screening for HL in primary care settings and communication trainings for providers may help reduce cancer screening disparities.
Comparison of Laboratory and Radiological Findings of Pregnant and Non-Pregnant Women with Covid-19
Authors: Ozer Kadir Burak , Sakin Onder , Koyuncu Kazibe , Cimenoglu Berk , Demirhan Recep
Published: April 2021

Objective Covid-19 became a pandemic, and researchers have not been able to establish a treatment algorithm. The pregnant population is also another concern for health care professionals. There are physiological changes related to pregnancy that result in different laboratory levels, radiological findings and disease progression. The goal of the present article is to determine whether the laboratory results and radiological findings were different in non-pregnant women (NPWs) of reproductive age and pregnant women (PWs) diagnosed with the Covid-19 infection.

Methods Out of 34 patients, 15 (44.11%) PWs and 19 (55.8%) NPWs were included in the study. Age, comorbidities, complaints, vitals, respiratory rates, computed tomography (CT) findings and stages, as well as laboratory parameters, were recorded from the hospital database.

Results The mean age of the PWs was of 27.6 ±  0.99 years, and that of the NPWs was of 37.63 ±  2.00; when age was compared between the groups, a statistically significant difference (p = 0.001) was found. The mean systolic blood pressure of the PWs was of 116.53 ±  11.35, and that of the NPWs was of 125.53 ±  13.00, and their difference was statistically significant (p = 0.05). The difference in the minimum respiratory rates of the patients was also statistically significant (p = 0.05). The platelet levels observed among the PWs with Covid-19 were lower than those of the NPWs (185.40 ±  39.09 × 109/mcL and 232.00 ±  71.04 × 109/mcL respectively; p = 0.05). The mean D-dimer value of the PWs was lower in comparison to that of the NPWs (p < 0.05).

Conclusion The laboratory findings and imaging studies may differ between pregnant and non-pregnant populations. It is important to properly interpret these studies. Future studies with a higher number of patients are required to confirm these preliminary data.
A Correlational Study on Taste Alterations and Quality of Life Among Cancer Patients
Authors: Wilson S. Darsana , Nair Chitra C. , Johns Christy , Mathew Christy , Joseph Dani , DSilva Precilla
Published: April 2021

Introduction One of the major problems faced by the world today is cancer. Cancer is an abnormal growth of cells. Chemotherapy, surgery, and radiation therapy are the treatment regimen for cancer. Prolonged use of chemotherapy drugs can cause different side effects such as alopecia, weight loss, sexual dysfunction, mood swings, and the most important one is taste alterations. The aim of the study is to determine the taste alterations (TAs) and quality of life (QOL) among cancer patients who have undergone three cycles of chemotherapy.

Methods The approach used is descriptive survey design. The sample comprised 62 cancer patients selected by convenient sampling. The tool used was baseline proforma, University of Washington Quality of Life (UW-QOL) questionnaire version 4.1, chemotherapy-induced taste alteration scale (CiTAS).

Results The majority of the patients belonged to the age group of 41 to 50 years (37.09%) among whom 40% were females. The majority of the patients were not diagnosed with any other disease (91.9%). Around 80.6% of patients reported to have sore mouth, out of whom 45.2% maintained oral care by brushing teeth. The most commonly seen type of tumor was head and neck (37.1%) whereas the tumor type genitourinary was the least seen (3.2%). The majority of the patients had stage II cancer (53.2%) and about 62% of them did not have metastasis. There is significant association with selected demographic variables and QOL (sore mouth, oral care, and tumor type). There is also a significant association with selected demographic variable and TAs, (oral care and tumor type) and there is a negative correlation between TAs and QOL.

Conclusion Identification of the severity of TA helps in providing alternative measures to improve the taste buds which may help in improving the QOL.
Metformin for Preventing Type 2 Diabetes Mellitus in Women with a Previous Diagnosis of Gestational Diabetes: A Narrative Review
Authors: Versace Vincent L. , Beks Hannah , Wesley Hannah , McNamara Kevin , Hague William , Anjana Ranjit Mohan , Mohan Viswanathan , Khunti Kamlesh , Dunbar James A.
Published: April 2021

Women with a history of gestational diabetes mellitus (GDM) are at greater risk of developing type 2 diabetes mellitus (T2DM) when compared with women who have not had GDM. To delay or prevent T2DM, guidelines recommend regular screening in the primary care setting and lifestyle interventions that are largely focused on dietary and physical activity modifications. As the postpartum period can be challenging for women, uptake and engagement in screening and lifestyle interventions have been poor. Poor uptake and engagement places women with a history of GDM at heightened risk for future morbidity and development of T2DM. Metformin has been a longstanding and safe treatment for the control of blood glucose in people with T2DM. Research has supported the efficacy of metformin, used as an adjunct to a lifestyle intervention or as a stand-alone treatment, in preventing T2DM in people at high risk of T2DM. Findings from longitudinal studies have demonstrated the potential for metformin to reduce conversion to T2DM when used by women with a previous diagnosis of GDM. This review examines the potential effectiveness of metformin to reduce the incidence of T2DM among women with a previous diagnosis of GDM in the “real-world” setting.
The first order expansion of a ground state energy of the ϕ4 model with cutoffs
Authors: Takaesu Toshimitsu
Published: April 2021

In this paper, we investigate the ϕ4 model with cutoffs. By introducing a spatial cutoff and a momentum cutoff, the total Hamiltonian is a self-adjoint operator on a boson Fock space. Under regularity conditions of the momentum cutoff, we obtain the first order expansion of a non-degenerate ground state energy of the total Hamiltonian.
Enhanced interlayer coupling and efficient photodetection response of in-situ grown MoS2–WS2 van der Waals heterostructures
Authors: Sinha Sneha , Kumar Sujit , Arora Sunil K. , Sharma Anjali , Tomar Monika , Wu Han-Chun , Gupta Vinay
Published: April 2021

Currently, 2D layered material (2DLM) based heterostructures, also known as van der Waals (vdW) heterostructures, are actively pursued owing to their great potential for optoelectronic applications. They are produced either by vertical stacking of individual layers or via in-plane stitching of 2DLMs. Producing vdW heterostructures with clean interfaces and growing them using direct growth methods are challenging. Herein, we report successful growth of large-area MoS2–WS2 vdW heterostructures (single- to few-monolayer, ML, the thickness of MoS2 and WS2) on oxidized Si (100) substrates using the catalyst-free Pulsed Laser Deposition technique. The in-plane (E12g) and out-of-plane (A1g) Raman-active phonon modes are used to probe the interlayer interactions between the constituent 2D layers. We observe a blueshift of 4.73 (1.63) cm−1 of the A1g peak corresponding to MoS2 (WS2) in the MoS2(1ML)–WS2(1ML) heterostructure compared to 1.27 (0.88) cm−1 for the homo-bilayers. The E12g mode also exhibited blueshift for the heterostructure and redshift for the bilayer of the constituent material. We show that the broadband photodetectors fabricated utilizing in situ grown MoS2–WS2 heterostructures exhibit responsivity, specific detectivity, and current on/off ratio as high as 2.51 × 105 A/W, 4.20 × 1014 Jones, and 1.05 × 105, respectively, under 24 μW/cm2 at 405 nm excitation. The successful fabrication of vdW heterostructures using a simple and scalable direct growth method and excellent photodetector performance pave the way for exploitation of their application potential and offer a playground to test some of the theoretical predictions.
High frequency impedance characteristics of a tunable microplasma device
Authors: Gautam Saurav , Morra Gabriele , Venkattraman Ayyaswamy
Published: April 2021

Computational studies on high frequency impedance characteristics of a microplasma device are reported. While microplasma is ignited using a primary excitation signal, frequency response of plasma impedance is determined by a secondary high frequency probe signal with significantly lower voltage amplitude such that it does not influence the plasma parameters. The computational model utilizing the drift–diffusion approximation is first validated by comparing with experimental data for microplasmas ignited at pressures ranging from 1 to 5 Torr. In spite of quantitative discrepancies, good overall agreement is obtained between the measured frequency response of impedance of the discharge. Comparisons are also presented for various plasma parameters including mean electron number density, sheath thickness, mean electron temperature, and collision frequency that were inferred from the impedance measurements. The computational model is then used to perform simulations of near-atmospheric pressure microplasmas with the probe signal frequency ranging from 3 to 20 GHz. The simulations demonstrate the presence of a resonance frequency at which the impedance vanishes. More importantly, it is shown that this resonant frequency can be tuned effectively by suitably modifying the operating parameters (gap size, pressure, and excitation voltage). The simulated impedance characteristics are used to determine the effective plasma inductance and capacitance using a non-linear fitting approach, thereby showing the dependence of these electrical parameters on the plasma operating conditions.
Understanding the sodium cation conductivity of human epileptic brain tissue
Authors: Emin David , Fallah Aria , Salamon Noriko , Yong William , Frew Andrew , Mathern Gary , Akhtari Massoud
Published: April 2021

Transient and frequency-dependent conductivity measurements on excised brain-tissue lesions from epilepsy patients indicate that sodium cations are the predominant charge carriers. The transient conductivity ultimately vanishes as ions encounter blockages. The initial and final values of the transient conductivity correspond to the high-frequency and low-frequency limits of the frequency-dependent conductivity, respectively. Carrier dynamics determines the conductivity between these limits. Typically, the conductivity rises monotonically with increasing frequency. By contrast, when pathology examinations found exceptionally disorganized excised tissue, the conductivity falls with increasing frequency as it approaches its high-frequency limit. To analyze these measurements, excised tissues are modeled as mixtures of “normal” tissue within which sodium cations can diffuse and “abnormal” tissue within which sodium cations are trapped. The decrease in the conductivity with increasing frequency indicates the predominance of trapping. The high-frequency conductivity decreases as the rate with which carriers are liberated from traps decreases. A relatively low conductivity results when most sodium cations remain trapped in “abnormal” brain tissue, while few move within “normal” brain tissue. Thus, the high densities of sodium nuclei observed by 23Na-MRI in epilepsy patients’ lesions are consistent with the low densities of diffusing sodium cations inferred from conductivity measurements of excised lesions.
Tuning the permeability of regular polymeric networks by the cross-link ratio
Authors: Milster Sebastian , Kim Won Kyu , Kanduč Matej , Dzubiella Joachim
Published: April 2021

The amount of cross-linking in the design of polymer materials is a key parameter for the modification of numerous physical properties, importantly, the permeability to molecular solutes. We consider networks with a diamond-like architecture and different cross-link ratios, concurring with a wide range of the polymer volume fraction. We particularly focus on the effect and the competition of two independent component-specific solute–polymer interactions, i.e., we distinguish between chain-monomers and cross-linkers, which individually act on the solutes and are altered to cover attractive and repulsive regimes. For this purpose, we employ coarse-grained, Langevin computer simulations to study how the cross-link ratio of polymer networks controls the solute partitioning, diffusion, and permeability. We observe different qualitative behaviors as a function of the cross-link ratio and interaction strengths. The permeability can be tuned ranging over two orders of magnitude relative to the reference bulk permeability. Finally, we provide scaling theories for the partitioning and diffusion that explicitly account for the component-specific interactions as well as the cross-link ratio and the polymer volume fraction. These are in overall good agreement with the simulation results and grant insight into the underlying physics, rationalizing how the cross-link ratio can be exploited to tune the solute permeability of polymeric networks.
Electrical spin-wave spectroscopy in nanoscale waveguides with nonuniform magnetization
Authors: Talmelli Giacomo , Narducci Daniele , Vanderveken Frederic , Heyns Marc , Irrera Fernanda , Asselberghs Inge , Radu Iuliana P. , Adelmann Christoph , Ciubotaru Florin
Published: April 2021

Spin wave modes in magnetic waveguides with the width down to 320 nm have been studied by electrical propagating spin-wave spectroscopy and micromagnetic simulations for both longitudinal and transverse magnetic bias fields. For longitudinal bias fields, a 1.3 GHz wide spin-wave band was observed in agreement with analytical dispersion relations for uniform magnetization. However, the transverse bias field led to several distinct bands, corresponding to different quantized width modes, with both negative and positive slopes. Micromagnetic simulations showed that, in this geometry, the magnetization was nonuniform and tilted due to the strong shape anisotropy of the waveguides. Simulations of the quantized spin-wave modes in such nonuniformly magnetized waveguides resulted in spin wave dispersion relations in good agreement with the experiments.
On the interaction between a diffraction shock wave and a cylindrical sulfur hexafluoride bubble
Authors: Zhu Yuejin , Jiang Chao , Zhang Penggang , Pan Zhenhua , Pan Jianfeng
Published: April 2021

The evolution of a cylindrical sulfur hexafluoride (SF6) bubble in the flow accelerated by a nonuniform diffraction shock is investigated using a density-based compressible OpenFOAM solver. The diffraction shock is generated from an initial planar shock with a Mach number of 2.2 by a rectangular barrier, and the influence of the barrier height on the evolution of the gas bubble is analyzed in detail both qualitatively and quantitatively. The results show that with increasing barrier height, the diffraction shock becomes weaker and propagates more slowly, which alters the shape of the undisturbed zone inside the gas bubble. The undisturbed zone becomes more slender, and shock focusing occurs at a later time. The local high-pressure point formed by the intersection of transmitted shocks in the case of shock diffraction can enhance the pressure during shock focusing. In addition, the intensity of vortex pairs of the distorted gas bubble becomes weaker as the barrier height increases. In the case of the highest barrier, the propagation velocity of the vortex pair emerging behind the deformed incident shock is subsonic, in contrast to the supersonic velocity found for other barrier heights. In addition, although the barrier heights considered here increase evenly in sequence, the degree of reduction of the local Mach number behind the deformed incident shock becomes larger.
Fracture mechanics analysis of rock containing collinear cracks under dynamic blasting loads
Authors: Zhang Lingfei , Chen Zhonghui , Wang Jianming , Shen Zuodong , Yang Jihai
Published: April 2021

Based on the superposition principle of fracture dynamics, the disturbance caused by dynamic blasting loads on the expansion of primary cracks in a typical slope was examined in this study. The stress intensity factor of the collinear double crack tip under the condition of mixed-mode dynamic and static loading was calculated. A dynamic response evaluation index was established, and the influence rules of blasting load amplitude, crack inclination angle, crack length, and crack spacing were analyzed theoretically. A collinear double-crack combination model was established and operated using ABAQUS software. The dynamic blasting load is shown to markedly increase crack propagation. Cracks with a 45° inclination angle are most intensely affected by the dynamic load. The crack length increases continuously as new cracks emerge under static load conditions; the dynamic load accelerates the penetration of the crack system. When the crack spacing is small, the penetration between them occurs more quickly. When the crack spacing increases to 10 mm, the unit shows multiple single crack failure modes. Response surface methodology was applied to obtain the multiple regression fitting function, which validates the theoretical analysis results. This work may provide a valuable reference for similar projects.
The Synthesis and Biological Evaluation of Some C-9 and C-10 Substituted Derivatives of the RNA Polymerase I Transcription Inhibitor CX-5461
Authors: Amarasiri Madushani , Vo Yen , Gardiner Michael G. , Poh Perlita , Soo Priscilla , Pavy Megan , Hein Nadine , Ferreira Rita , Hannan Katherine M. , Hannan Ross D. , Banwell Martin G.
Published: April 2021

The regio-isomeric alkynyl-substituted derivatives, 2 and 3, of the RNA Polymerase I (Pol I) transcription inhibitor CX-5461 (1) were prepared and the active one (compound 3) subjected to click reactions ([3 + 2]-cycloaddition reactions) with certain alkyl azides bearing biotin or fluorescent tags. Compounds 2 and 3, as well as four [3 + 2]-cycloadducts of the latter, were subjected to biological evaluation in a human acute myeloid leukemia cell line model. Among the six compounds tested only alkyne 3 remained active but this was less potent than parent 1.
Mendelian randomization identifies blood metabolites previously linked to midlife cognition as causal candidates in Alzheimer’s disease
Authors: Lord Jodie , Jermy Bradley , Green Rebecca , Wong Andrew , Xu Jin , Legido-Quigley Cristina , Dobson Richard , Richards Marcus , Proitsi Petroula
Published: April 2021

Significance

The absence of disease-modifying therapeutics for Alzheimer’s disease (AD) continues, and an understanding of early, easily accessible biomarkers to inform treatment strategies remains elusive. This study uses knowledge of blood metabolites previously associated with midlife cognition—a preclinical predictor of AD—to systematically investigate causal associations with later AD status. Given that the pathological changes underlying AD are thought to develop years before clinical manifestations of the disease, developing these findings further could hold special utility in informing early treatment intervention.
Anti-carbamylated protein antibodies positivity and disease activity in Hispanic patients with established rheumatoid arthritis: An observational study
Authors: Vega-Morales David , Garza-Elizondo Mario A , Trouw Leendert A , Gonzalez-Torres Karina I , Torres-Lopez Ernesto , Eguia-Bernal Miryam , Loredo-Alanis Salvador A , Gracia-Arechiga Tayde S , Vazquez-Fuentes Brenda R , Castañeda-Martinez Diana D , Castañeda-Martinez Martha M , Elizondo-Solis Cesar V , Mendiola-Jimenez Andres , Salinas-Carmona Mario C , Herrera-Sandate Pablo , la Garza Jesus A Cardenas-de , Rodriguez-Sanchez Gerardo E , Galarza-Delgado Dionicio A
Published: April 2021

Objectives

We aimed to determine the prevalence of anti-carbamylated protein (anti-CarP) antibodies in Mexican Hispanics with established rheumatoid arthritis (RA) and to assess their relationship with disease activity.

Methods

A cohort study was conducted in 278 patients with established RA during an 18-month follow-up. We measured IgG/IgM/IgA rheumatoid factor (RF), IgG anticitrullinated protein antibodies (ACPA) and IgG/IgM/IgA anti-CarP antibodies using enzyme-linked immunosorbent assay (ELISA). For disease activity, we performed the 28-joint disease activity score with erythrocyte sedimentation rate (DAS28-ESR). Repeated measures one-way ANOVA was used to test the association between anti-CarP IgG antibody status and longitudinal DAS28-ESR scores. Patients were evaluated at baseline and at 6, 12, and 18 months during follow-up.

Results

Anti-CarP IgG antibodies were positive in 47.8% of patients and, accounting for all isotypes, in 9.5% of patients with negative RF and ACPA. Triple antibody positivity was present in 42.6% of patients in our sample. Anti-CarP IgG antibody positivity did not show statistically significant differences in mean DAS28-ESR when compared to anti-CarP IgG antibody negative patients at baseline, 6, 12 or 18 months.

Conclusion

Anti-CarP IgG antibodies are not associated to a higher disease activity in Hispanic patients with established RA. Our findings suggest that the clinical value of measuring anti-CarP antibodies in RA diminishes over time.
COPII collar defines the boundary between ER and ER exit site and does not coat cargo containers
Authors: Shomron Olga , Nevo-Yassaf Inbar , Aviad Tamar , Yaffe Yakey , Zahavi Eitan Erez , Dukhovny Anna , Perlson Eran , Brodsky Ilya , Yeheskel Adva , Pasmanik-Chor Metsada , Mironov Anna , Beznoussenko Galina V. , Mironov Alexander A. , Sklan Ella H. , Patterson George H. , Yonemura Yoji , Sannai Mara , Kaether Christoph , Hirschberg Koret
Published: April 2021

COPII and COPI mediate the formation of membrane vesicles translocating in opposite directions within the secretory pathway. Live-cell and electron microscopy revealed a novel mode of function for COPII during cargo export from the ER. COPII is recruited to membranes defining the boundary between the ER and ER exit sites, facilitating selective cargo concentration. Using direct observation of living cells, we monitored cargo selection processes, accumulation, and fission of COPII-free ERES membranes. CRISPR/Cas12a tagging, the RUSH system, and pharmaceutical and genetic perturbations of ER-Golgi transport demonstrated that the COPII coat remains bound to the ER–ERES boundary during protein export. Manipulation of the cargo-binding domain in COPII Sec24B prohibits cargo accumulation in ERES. These findings suggest a role for COPII in selecting and concentrating exported cargo rather than coating Golgi-bound carriers. These findings transform our understanding of coat proteins’ role in ER-to-Golgi transport.
Food for thought: How cell adhesion coordinates nutrient sensing
Authors: Hamidi Hellyeh , Ivaska Johanna
Published: April 2021

Cell adhesion controls cell survival and proliferation via multiple mechanisms. Rabanal-Ruiz et al. (2021. J. Cell Biol.https://doi.org/10.1083/jcb.202004010) demonstrate that focal adhesions are key signaling hubs for cellular nutrient sensing and signaling.
Force AFRIMETS supplementary comparison AFRIMETS.M.F-S2
Authors: Bangi Josephat Obwoge , Seidel Mark , Dlamini Sipho , Matosse James
Published: April 2021

Main text

The Regional Metrology Organization AFRIMETS Technical Committee in Mass and related Quantities (TCM) Working Group Force (WGF) met in July 2018 in Enugu Nigeria during the 12th General Assembly (GA) and made a decision to carry out an AFRIMETS supplementary comparison for the unit of force. This comparison, named the AFRIMETS.M. F-S2 supplementary comparison, in the force range of 250 kN and 500 kN. This comparison was planned to demonstrate the degree of equivalence between the national standards of force and to provide evidence for the Calibration and Measurement Capability (CMCs) claimed by the participating National Metrology Institutes (NMIs) in the AFRIMETS region, and particularly the who did not participate in the global CCM.F-K2 KC. The AFRIMETS TCM approved that KEBS of Kenya to serve as the pilot laboratory. and PTB of Germany to would be link laboratories. Although not part of the AFRIMETS region, PTB from EURAMET was invited to participate and provided the reference values while NMISA provided the transfer standards used during the comparison.

To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.

The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
Addendum to ‘EPRL/FK asymptotics and the flatness problem’
Authors: Engle J , Kaminski W , Oliveira J
Published: April 2021

We show that, when an approximation used in this prior work is removed, the resulting improved calculation yields an alternative derivation, in the particular case studied, of the accidental curvature constraint of Hellmann and Kaminski. The result is at the same time extended to apply to almost all non-degenerate Regge-like boundary data and a broad class of face amplitudes. This resolves a tension in the literature.
Effects of high density phase transitions on neutron star dynamics
Authors: Liebling Steven L , Palenzuela Carlos , Lehner Luis
Published: April 2021

Various theoretical arguments motivate an expectation of a phase transition in matter at extreme densities above nuclear density, accompanied by hopes that gravitational wave observations may reveal the properties of such a transition. Instead of adopting a particular theory, we consider here a generic form of first order phase transition using a piecewise polytropic equation of state, and evolve both isolated neutron stars and neutron star binaries, including unequal mass binaries and, in some cases, magnetic field, looking at dynamical effects. Of particular interest are effects that may be observable either via gravitational waves or electromagnetic observations.
Quadratic and cubic spherically symmetric black holes in the modified teleparallel equivalent of general relativity: energy and thermodynamics
Authors: Nashed G G L
Published: April 2021

In Bahamonde et al (2019 arXiv:1907.10858 [gr-qc]), a spherically symmetric black hole (BH) was derived from the quadratic form of f(T). Here we derive the associated energy, invariants of curvature, and torsion of this BH and demonstrate that the higher-order contribution of torsion renders the singularity weaker compared with the Schwarzschild BH of general relativity (GR). Moreover, we calculate the thermodynamic quantities and reveal the effect of the higher-order contribution on these quantities. Therefore, we derive a new spherically symmetric BH from the cubic form of

f

(

T

)

=
T
+
ϵ

1

2

α

T

2

+

1

3

β

T

3

, where ϵ ≪ 1, α, and β are constants. The new BH is characterized by the two constants α and β in addition to ϵ. At ϵ = 0 we return to GR. We study the physics of these new BH solutions via the same procedure that was applied for the quadratic BH. Moreover, we demonstrate that the contribution of the higher-order torsion,

1

2

α

T

2

+

1

3

β

T

3

, may afford an interesting physics.
Spherical surface and volume averages in electrostatics using Green’s reciprocity theorem
Authors: Kovács Vivien , Pálfalvi László
Published: April 2021

In the present work we apply Green’s reciprocity theorem for the determination of surface and volume averages of the potential and electric field over an imaginary sphere in an electrostatic field. To the best of our knowledge this approach has not been used so far for such averaging. The derived results have importance when studying the properties and behaviour of dielectric media.
The variational method applied to the harmonic oscillator in the presence of a delta function potential
Authors: Ghose Indrajit , Sen Parongama
Published: April 2021

The problem of the harmonic oscillator with a centrally located delta function potential can be exactly solved in one dimension, where the eigenfunctions are expressed as superpositions of the Hermite polynomials or as confluent hypergeometric functions in general. The eigenfunctions obtained exactly are difficult to visualise and hence, to gain more insight, one can attempt to use model wave functions which are explicitly and simply expressed. Here, we apply the variational method to verify how closely one can approach the exact ground state eigenvalues using such trial wave functions. We obtain the estimates of the ground state energies, which are closer to the exact values in comparison to earlier approximate results for both the repulsive and attractive delta potentials.
Feshbach resonances of nonzero partial waves at different collision energies
Authors: Li Li-Hang , Hai Yang , Lyu Bing-Kuan , Wang Gao-Ren , Cong Shu-Lin
Published: April 2021

Taking the ultracold 85Rb–87Rb collision system as an example, we investigated the Feshbach resonances of nonzero partial waves above the threshold. The self-energy at the threshold, which represents the coupling strength between open and closed channels, is considered a critical parameter to quantitatively describe the properties of Feshbach resonances. The total elastic and inelastic cross sections are calculated as functions of the magnetic field B and collision energy E
col, ranging from 0.1 to 600 μK. For a large absolute value of the self-energy at the threshold, the resonance decays rapidly with increasing collision energy, and narrow resonances of nonzero partial waves can be clearly resolved in the contour plot of the inelastic cross section versus the collision energy and magnetic field. It was found that the resonance tail appeared at the given magnetic field when the cross section decreased from the maximal value of the resonance peak to the minimum value, where a long resonance tail indicates an appreciable resonance in a relatively large region of collision energy. This relationship between the self-energy and the properties of Feshbach resonances still exists in the thermally averaged inelastic rate coefficient. The bound-state energies for nonzero partial waves split owing to the spin–spin interaction, which results in multiple nearly-overlapping resonances. Both the spin–spin and second-order spin–orbit effects are included. However, multiple nearly-overlapping resonances for nonzero partial waves are difficult to resolve in thermally averaged rate coefficients.
Review of lead-free Bi-based dielectric ceramics for energy-storage applications
Authors: Li Lisong , Fan Pengyuan , Wang Mengqi , Takesue Naohisa , Salamon David , Vtyurin Alexander N , Zhang Yangjun , Tan Hua , Nan Bo , Lu Ya , Liu Laijun , Zhang Haibo
Published: April 2021

Dielectric energy-storage ceramics have the advantages of high power density and fast charge and discharge rates, and are considered to be excellent candidate materials for pulsed power-storage capacitors. At present, the application of dielectric energy-storage ceramics is hindered by their low energy density and the fact that most of them contain elemental lead. Therefore, lead-free dielectric energy-storage ceramics with high energy storage density have become a research hot spot. In this paper, we first present the requirements that dielectric energy-storage capacitors impose on the properties of ceramic materials. We then review our previous research work combined with research progress into bismuth (Bi)-based lead-free energy-storage ceramics including Bi0.5Na0.5TiO3 (BNT), BiFeO3, and Bi0.2Sr0.7TiO3, in which the composition design ideas and related energy-storage characteristics of BNT-based lead-free energy-storage ceramics are emphasized. At the same time, we highlight the problems faced by Bi-based lead-free energy-storage ceramics and some strategies for addressing them. Finally, we examine the future prospects of research into Bi-based lead-free energy-storage ceramics.
Lock-in technique for precise measurement of ion distribution functions
Authors: Lütke Stetzkamp Christian , Tsankov Tsanko Vaskov , Czarnetzki Uwe
Published: April 2021

Retarding field energy analyzers are commonly used for the experimental determination of the distribution of ions. Measurements require taking the first derivative of the measured current with respect to the retarding voltage, which limits the accuracy of the results. Here a commercial energy analyzer is combined with a lock-in detection and AC modulation technique to obtain ion distribution functions with an improved dynamic range. The technical realization of the method together with its theoretical motivation are presented. The various challenges for implementing the technique and ways to address them are given. The energy resolution of the method is discussed based on the concept of transfer functions, and the influence of the various adjustable parameters (grid bias voltages, frequency and amplitude of the modulation signal) on the obtained results are studied. The application of the method to an inductive discharge readily shows a dynamic range of more than three orders of magnitude. This dynamic range provides information on additional plasma parameters, such as the potential and the plasma density at the sheath edge and in the center of the discharge. Possibilities for further improvement of the technique are discussed.
Frustration in block copolymer assemblies
Authors: Shi An-Chang
Published: April 2021

Frustration is ubiquitous in condensed matter systems and it provides a central concept to understand the self-assembly of soft matter. Frustration is found at multiple scales in polymeric systems containing block copolymers. At the molecular scale, frustration arises because the chemically distinct blocks repel each other whereas the chain connectivity prevents a macroscopic separation. At the mesoscopic scale, frustration occurs due to the competition between the tendency for the block copolymer assemblies to maintain their native shape and the requirement to fill the space. At an even larger scale, frustrations could be induced by external fields or spatial confinement. Recent theoretical and experimental studies provide a good understanding of the origin of various frustrations in the self-assembly of block copolymers. Furthermore, it has been demonstrated that designed block copolymer systems, either in the form of multiblock copolymers with different architectures or block copolymer blends, could be utilized to regulate frustrations resulting in the formation of complex ordered and hierarchically structured phases.
A new phantom developed to test the ATCM performance of chest CT scanners
Authors: Yang Yang , Zhuo Weihai , Chen Bo , Lu Shunqi , Zhou Pei , Ren Wenliang , Liu Haikuan
Published: April 2021

In this study, a new ATCM phantom was developed to test the performance of the automatic tube current modulation (ATCM) of computed tomography (CT) scanners.. Based on the Chinese reference man and Monte Carlo simulations of x-ray attenuation, a more realistic ATCM phantom made of polymethyl methacrylate was developed. The phantom has a length of 20 cm, and it can be used to measure the dose profile along the central axis using 19 real-time MOSFET detectors. The image noise can be calculated slice by slice in the phantom’s center. Test experiments showed that the phantom could initiate tube current modulation under different modulation levels of CT scans, and the actual effects of ATCM could be evaluated with the aid of the dose profile measurements. Using the measured dose profiles and image noise, the preferred dose can easily be identified from a choice of different modulation levels. The new phantom developed in this study can be used to test the ATCM performance of CT scanners, and is useful for further studies of the optimization of CT scan protocols with ATCM.
Surface-confinement assisted synthesis of nitrogen-rich single atom Fe−N/C electrocatalyst with dual nitrogen sources for enhanced oxygen reduction reaction
Authors: Cui Yaqi , Xu Jiaoxing , Zhao Yi , Guan Lunhui
Published: April 2021

The utilization of earth abundant iron and nitrogen doped carbon as a precious-metal-free electrocatalyst for oxygen reduction reaction (ORR) significantly depends on the rational design and construction of desired Fe−N
x
moieties on carbon substrates, which however remains an enormous challenge. Herein a typical nanoporous nitrogen-rich single atom Fe−N/C electrocatalyst on carbon nanotube (NR-CNT@FeN-PC) was successfully prepared by using CNT as carbon substrate, polyaniline (PANI) and dicyandiamine (DCD) as binary nitrogen sources and silica-confinement-assisted pyrolysis, which not only facilitate rich N-doping for the inhibition of the Fe agglomeration and the formation of single atom Fe−N
x
sites in carbon matrix, but also generate more micropores for enlarging BET specific surface area (up to 1500 m2·g−1). Benefiting from the advanced composition, nanoporous structure and surface hydrophilicity to guarantee the sufficient accessible active sites for ORR, the NR-CNT@FeN-PC catalyst under optimized conditions delivers prominent ORR performance with a half-wave potential (0.88 V versus RHE) surpass commercial Pt/C catalyst by 20 mV in alkaline electrolyte. When assembled in a home-made Zn−air battery device as cathodic catalyst, it achieved a maximum output power density of 246 mW·cm−2 and a specific capacity of 719 mA·h·g−1
Zn outperformed commercial Pt/C catalyst, holding encouraging promise for the application in metal-air batteries.
Targeted antitumor comparison study between dopamine self-polymerization and traditional synthesis for nanoparticle surface modification in drug delivery
Authors: Zhang Mengying , Zou Yuan , Zuo Cuiling , Ao Hui , Guo Yifei , Wang Xiangtao , Han Meihua
Published: April 2021

To improve the therapeutic efficacy of anticancer agents and extend their application, mussel-inspired chemical modifications have attracted considerable attention. Surface modification based on polydopamine (PDA) has been a facile and versatile method to immobilize biomolecules on substrates for targeted drug delivery. To better analyze pharmaceutical differences between PDA-based surface modification and traditional synthesis methods, we prepared two kinds of folate (FA)-targeted nanoparticles (NPs) loaded with paclitaxel (PTX). The resultant PTX-PDA-FA NPs and PTX-FA NPs represented PDA and synthesis strategies, respectively. PTX-PDA-FA NPs and PTX-FA NPs have been characterized. The particle size of PTX-PDA-FA NPs was smaller than that of PTX-FA NPs. The two kinds of NPs both exhibited long-rod morphology, good colloidal stability and sustained slow drug release. Cytotoxicity in vitro was evaluated, and antitumor efficacy was investigated against 4T1 tumor-bearing mice. The tumor targeting therapeutic index of PTX-PDA-FA NPs and PTX-FA NPs showed equivalent superior specificity compared to nontargeted groups, which indicated that FA successfully attached to the surface of NPs by the PDA method and that the antitumor effect was equivalent to that of FA-modified NPs prepared by the chemical synthesis method. These results further indicated that PDA, as a simple and effective chemical surface modification platform, could be developed and applied in targeted delivery systems.
Effect of carbon nano tube in the structural and physical properties of polyvinyl chloride films
Authors: Helal A I , Vshivkov S A , Zaki M F , Elkalashy Sh I , Soliman T S
Published: April 2021

Polyvinyl chloride (PVC) films loaded by different concentration of Carbon Nano Tubes (CNT) are prepared through a solution casting method. CNT are characterized using transmission electron microscope (TEM) and x-ray diffractometer (XRD). The analysis of the PVC-CNT films is carried out by using XRD, scanning electron microscope (SEM), and Fourier transform infrared (FTIR) to study the change in the polymer structure. UV–vis spectrophotometer is used to determine the optical parameters depending on the optical absorption data. It is found that, the direct and indirect optical band gap decrease with an increase in CNT nanoparticle content in the PVC matrix. The refractive index, optical dielectric parameters, and optical conductivity of the polymer films are investigated using the optical absorption data. These parameters are enhanced with the increase in the CNT concentration in the PVC matrix. The Wemple-DiDomenico model is used to calculate the optical dispersion parameters (like; oscillator energy, dispersion energy, static refractive index, dipole strength, and static optical dielectric constant). In addition, nonlinear refractive index, linear optical susceptibility, and third-order nonlinear optical susceptibility are investigated.
Cosmological simulation in tides: power spectra, halo shape responses, and shape assembly bias
Authors: Akitsu Kazuyuki , Li Yin , Okumura Teppei
Published: April 2021

The well-developed separate universe technique enables
accurate calibration of the response of any observable to an
isotropic long-wavelength density fluctuation. The large-scale
environment also hosts tidal modes that perturb all observables
anisotropically. As in the separate universe, both the long tidal
and density modes can be absorbed by an effective anisotropic
background, on which the interaction and evolution of the short
modes change accordingly. We further develop the tidal simulation
method, including proper corrections to the second order Lagrangian
perturbation theory (2LPT) to generate initial conditions of the
simulations. We measure the linear tidal responses of the matter
power spectrum, at high redshift from our modified 2LPT, and at low
redshift from the tidal simulations. Our results agree
qualitatively with previous works, but exhibit quantitative
differences in both cases. We also measure the linear tidal
response of the halo shapes, or the shape bias, and find its
universal relation with the linear halo bias, for which we provide a
fitting formula. Furthermore, analogous to the assembly bias, we
study the secondary dependence of the shape bias, and discover for
the first time the dependence on the halo concentration and axis
ratio. Our results provide useful insights for studies of the
intrinsic alignment as a source of either contamination or
information. These effects need to be correctly taken into account
when one uses intrinsic alignments of galaxy shapes as a precision
cosmological tool.
Palatini double-well and Coleman-Weinberg potentials with non-minimal coupling
Authors: Bostan Nilay
Published: April 2021

We present the impact of non-minimal coupling ξϕ2
R on the inflationary parameters by taking into account the models of single-field inflation with the inflaton that has a non-zero vacuum expectation value (v) after the period of inflation in Palatini gravity. We discuss the well-known symmetry-breaking type potentials, namely the double-well potential and Coleman-Weinberg potential. We show that the inflationary predictions, n
s and r, of these potentials for both ϕ > v and ϕ < v inflation are compatible with the recent measurements within the regions of the v-ξ plane. Finally, we take into account the inflationary predictions of Coleman-Weinberg potential for selected ξ values as a function of v in the Palatini formalism.
Gravitational waves from dark sectors, oscillating inflatons, and mass boosted dark matter
Authors: Bhoonah Amit , Bramante Joseph , Nerval Simran , Song Ningqiang
Published: April 2021

Gravitational wave signatures from dynamical scalar field configurations provide a compelling observational window on the early universe. Here we identify intriguing connections between dark matter and scalars fields that emit gravitational waves, either through a first order phase transition or oscillating after inflation. To study gravitational waves from first order phase transitions, we investigate a simplified model consisting of a heavy scalar coupled to a vector and fermion field. We then compute gravitational wave spectra sourced by inflaton field configurations oscillating after E-Model and T-Model inflation. Some of these gravitational wave signatures can be uncovered by the future Big Bang Observatory, although in general we find that MHz-GHz frequency gravitational wave sensitivity will be critical for discovering the heaviest dark sectors. Intriguingly, we find that scalars undergoing phase transitions, along with E-Model and T-Model potentials, can impel a late-time dark matter mass boost and generate up to Planck mass dark matter. For phase transitions and oscillating inflatons, the largest dark matter mass boosts correspond to higher amplitude stochastic gravitational wave backgrounds.
Primordial non-Gaussianity from G-inflation
Authors: Zhang Fengge , Gong Yungui , Lin Jiong , Lu Yizhou , Yi Zhu
Published: April 2021

Enormous information about interactions is contained in the non-Gaussianities of the primordial curvature perturbations, which are essential to break the degeneracy of inflationary models. We study the primordial bispectra for G-inflation models predicting both sharp and broad peaks in the primordial scalar power spectrum. We calculate the non-Gaussianity parameter f
NL in the equilateral limit and squeezed limit numerically, and confirm that the consistency relation holds in these models. Even though f
NL becomes large at the scales before the power spectrum reaches the peak and the scales where there are wiggles in the power spectrum, it remains to be small at the peak scales. Therefore, the contributions of non-Gaussianity to the scalar induced secondary gravitational waves and primordial black hole abundance are expected to be negligible.