bluuebunny/crossref_metadata_2025 huggingface dataset:
Reducing the Need for Cutting Fluids in Drilling by Means of Modulation Assisted Drilling
Authors: Ackroyd B. , Compton W. D. , Chandrasekar S.
Published: January 2022

The superposition of controlled modulation during drilling is known to result in consistent chip breakage under a wide variety of operating conditions in materials such as aluminum and steel. Modulation is shown to be equally effective to cutting fluids in reducing mean force levels and may provide reduced mean force levels even under operating conditions where cutting fluids are ineffective. The replacement of cutting fluid with modulation has no significant deteriorating effect on surface finish. These observations suggest that the use of superimposed low-frequency modulation could reduce the need for cutting fluids in drilling.
Isophote Based Machining for Feature Intensive Surfaces
Authors: Han Zhonglin , Yang Daniel C. H.
Published: January 2022

This paper presents a novel approach for generating efficient tool paths in machining free-form surfaces. Concept of iso-phote is used to facilitate tool-path generation. An iso-phote is defined as a region on a surface where the normal vector does not differ by more than a prescribed angle from a fixed reference vector. The boundary curves of the iso-phote, called iso-inclination curves, are numerically generated and are served as the initial master tool paths. These iso-inclination curves are then projected to a 2D plane which is perpendicular to the fixed reference vector. 2D curve offsetting of the projected iso-inclination curve is then performed. The resulted 2D offset curves are projected back to 3D surface to form final tool paths. The resulted tool paths can guarantee the satisfaction of machining tolerance requirements. A comparison study of this iso-phote based machining with the conventional iso-parametric machining and the iso-planar machining shows favorite result for the new approach.
Avoiding Exit Burr in CNC End Milling by an Adapted Tool Path
Authors: Hassamontr Jaramporn , Blondaz Laurent , Dornfeld David A.
Published: January 2022

Most machining processes often require secondary operations such as edge finishing to improve the part’s form and function. The cost of the edge finishing operation can be significant, but is often neglected by part designers and process planners. In many cases, it is possible to avoid edge finishing process if the part’s edge quality is taken into consideration during part design and process planning stages. In milling, it has been known for some time that when the tool leaves the part while removing work material, burrs are likely to form. With this fundamental knowledge, a tool path generation algorithm that avoids exit burr formation was developed in this paper. The developed algorithm makes use of a traditional window framing tool path generation scheme. The validity of the algorithm is also investigated. Lastly, a comparison between the developed algorithm and traditional zigzag tool path planning algorithms is made.
Compliant Kinematic Couplings for Use in Manufacturing and Assembly
Authors: Culpepper Martin L. , Slocum Alexander H. , Shaikh F. Zafar
Published: January 2022

Repeatable positioning and rigid coupling are critical to manufacturing processes. Traditionally, pin joints and elastic averaging methods have been used to create reasonably repeatable and stiff joints. However, for repeatability below 200 μinches (5μm) these methods become expensive to manufacture. Less often used, are kinematic couplings which can attain sub-micron level repeatability, but have limited stiffness and don’t allow the mating of surfaces (as required in casting.)

In this paper, a new type of coupling, a compliant kinematic coupling, which combines the desirable characteristics of many methods is presented. The result is a coupling with the stiffness characteristics of elastically averaged couplings, good repeatability, and the ability to allow surfaces to mate. Repeatability tests in low cost versions of these couplings show radial repeatability of 200μinch (5μm) and angular repeatability of 57 μradians. This coupling method can be used in casting, assembly, fixturing, sheet metal forming, and other processes.
Capabilities of Parallel Link Machine Tools: Preliminary Investigations of the Variax Hexacenter™
Authors: Whittingham Ben D. , Gindy Nabil N. Z. , Chrisp Anthony G. , Powell Nigel P. , Geldart Mark , Al-Habaibeh Amin , Wykes Catherine M. , Ratchev Svetan M. , Webb Phil
Published: January 2022

This paper aims to highlight the work being done by the Rapid Response Aerospace Manufacture (RRAM) research group at the University of Nottingham in the area of capability investigations of parallel link machine tools. The paper focuses on the Giddings and Lewis Variax Hexacenter™, which has been in operation at the University of Nottingham’s Department of Manufacturing Engineering and Operations Management since September 1997.

In the first section of the paper the concept of parallel link machine tools is described, as well as the application of the Variax within the context of a responsive manufacturing cell. The second section details some of the standard machine capability tests applied to parallel link machines, and summarises the test results carried out to date on the Variax. The third section describes some aspects requiring investigation beyond these initial tests, and highlights the areas of knowledge which are generally underinvestigated for parallel link machines. An outline of the research being undertaken by the RRAM group to address these areas is then briefly described.
Elasto-Plastic Finite Element Analysis of Indentations in Free Abrasive Machining
Authors: Bhagavat Milind , Yang Fuqian , Kao Imin
Published: January 2022

Free abrasive machining (FAM) using a wiresaw is emerging as a state of the art technology for slicing large diameter semiconductor wafers. Material removal in a FAM environment is known to be by rolling and indenting of abrasives into the cut media. Therefore, indentation by abrasives in the slurry is the single most important mechanism in wiresawing process. This paper deals with the importance of abrasive shape in material removal during FAM. To achieve this objective, indentation by conical rigid abrasives of different included angles has been investigated using finite element method (FEM). Typical indentation fracture involving median, radial and transverse cracking has been explained to the maximum level of sophistication attainable using static stress analysis. Some industrially relevant results pertaining to FAM in general and wire-sawing in particular have been proposed.
Free Vibration Behavior of Unidirectional Composite Cylindrical Helical Springs With Circular Section
Authors: Yildirim Vebil , Sancaktar Erol
Published: January 2022

The free vibration problem of unidirectional composite cylindrical helical springs is modeled theoretically as a continuous system considering the rotary inertia, shear and axial deformation effects. The first order shear deformation theory is employed in the mathematical model. The twelve scalar ordinary differential equations governing the free vibration behavior of cylindrical helical springs made of an anisotropic material are solved simultaneously by the transfer matrix method. The overall transfer matrix of the helix is computed up to any desired accuracy by using the effective numerical algorithm available in the literature. The theoretical results are verified with the reported values, which were obtained theoretically and experimentally for straight beams. A parametric study is performed to investigate the effects of the number of active coils, the helix pitch angle and material types on the fundamental natural frequencies of helical springs with circular section and fixed-fixed ends.
The Development and Validation of Design-Oriented Metrics for Fretting Fatigue in Titanium Engine Components
Authors: Szolwinski M. P. , Harish G. , Farris T. N.
Published: January 2022

The area of contact between the blade root and disk in high-performance turbomachinery has been identified as a critical area for the nucleation of fatigue damage leading to premature and often catastrophic componential failures. The combination of high cycle aerodynamic and low cycle inertial loads lead to distributions of both normal and shear tractions at the blade/disk interface, leading to an aggressive tribological damage mechanism known as fretting. The interaction of small-scale, oscillatory relative displacements or slip at the contact surfaces and the sharp gradients of near-surface contact stresses induced by fretting contact is responsible for the nucleation of near-surface fatigue damage in these components. The paper will summarize efforts targeted at the development and validation of design-oriented tools for assessing quantitatively the threat of fretting fatigue to the integrity and subsequent performance of jet engine components.
A Multiparameter Model for the Prediction of Fatigue Crack Growth
Authors: Soboyejo A. B. O. , Foster M. A. , Katsube N. , Soboyejo W. O.
Published: January 2022

A new multiparameter model is proposed for the characterization of fatigue crack growth. The model assesses the combined effects of identifiable multiple variables that can contribute to fatigue crack growth. Mathematical expressions are presented for the determination of fatigue crack growth rates, da/dN, as functions of multiple variables, such as: stress intensity factor range, ΔK; stress ratio, R; closure stress intensity factor, Kmax, Kcl and the maximum stress intensity factor, frequency, Ω and temperature, T. A generalized emperical methodology is proposed for the estimation of fatigue crack growth rates as functions of these variables. The validity of the new methodology is then verified by making appropriate comparisons between predicted and measured fatigue crack growth data obtained from experiments on Ti-6Al-4V, in-conel 718 and HY80 steel. The multiparameter predictions are shown to be in close agreement with experimental data.
MEMS Testing Techniques for Long-Term Stability
Authors: Brown Stuart , Muhlstein Christopher , Abnet Cameron , Chui Clarence
Published: January 2022

Development of film processing technologies in the past decade has allowed the rapid application of MEMS to long-term, safety-critical and high performance applications. However, our understanding of the fundamental limitations of these small, structural components has evolved more slowly. The Micro-Structural Research Laboratory (μ-SRL) at Exponent has led the development of mechanical testing and qualification procedures for government and corporate MEMS. Current efforts to characterize mechanical properties of structural films include evaluating elastic properties and strength, fracture toughness, fatigue crack initiation and growth, and time-dependent phenomena such as creep.
Size Effects on Mechanical Properties of Polysilicon
Authors: Sharpe William N.
Published: January 2022

Polysilicon (chemically vapor deposited polycrystalline silicon) is the predominant structural material for MEMS products where the components have thicknesses of ten microns or less and minimum feature sizes of one micron or less. Although a corresponding bulk polysilicon manufactured in the same manner does not exist, it is nevertheless important to know whether the size of the manufactured component affects the Young’s modulus and strength of the material. This is still an open question, but there is research underway. A comprehensive survey is not intended here; Sharpe et al. (1997) contains a summary as of the end of 1996. The presentation will discuss recent developments in modulus and strength measurements with emphasis on electrostatic tensile tests.
Three-Dimensional Singular Stresses in Open Hole and Rigid Fastener Composites
Authors: Iarve E. V.
Published: January 2022

A three-dimensional solution valid in a composite laminate with a rigid fastener hole is obtained by combining a singular asymptotic solution with the B-spline displacement approximation. The hybrid approximation developed for the open hole problems was extended to rigid fastener hole problems. A near singular term of the asymptotic expansion present in the filled hole problem only was taken into account in order to obtain convergent solution with coarse spline approximation mesh. A bearing loaded [45/-45]s laminate was considered, and the multiplicative factors of the singular stress terms at the hole edge and ply interface were obtained.
Understanding the Law of Conservation of Momentum in One-Dimensional
Collisions Between Two Objects Using the Velocity Space Approach
Authors: Wong Kin Son , Wong Hang
Published: January 2022

The law of conservation of momentum is a fundamental law of nature. It states that the momentum of an isolated system is conserved. In high school or introductory-level physics courses, for simplicity, teachers and textbooks always use collisions in one dimension as the examples to introduce the concept of conservation of momentum. To solve simple problems involving one-dimensional collisions, all we need are basic algebraic manipulations. However, the relation between physical quantities, such as mass and the changes in velocity and kinetic energy, of the colliding objects is not obvious. For instance, if an object A collides with a stationary object B, what is the direction of A after the collision? Is it possible that the final velocity of A is zero in an inelastic collision? In this paper, we argue that the so-called velocity space approach can be highly effective for physics teachers in building a better understanding of the law of conservation of momentum.
Out of sight, out of mind: The influence of communicative load and phonological neighborhood density on phonetic variation in real listener-directed speech
Authors: Scarborough Rebecca , Zellou Georgia
Published: January 2022

Some models of speech production propose that speech variation reflects an adaptive trade-off between the needs of the listener and constraints on the speaker. The current study considers communicative load as both a situational and lexical variable that influences phonetic variation in speech to real interlocutors. The current study investigates whether the presence or absence of a target word in the sight of a real listener influences speakers' patterns of variation during a communicative task. To test how lexical difficulty also modulates intelligibility, target words varied in phonological neighborhood density (ND), a measure of lexical difficulty. Acoustic analyses reveal that speakers produced longer vowels in words that were not visually present for the listener to see, compared to when the listener could see those words. This suggests that speakers assess in real time the presence or absence of supportive visual information in assessing listener comprehension difficulty. Furthermore, the presence or absence of the word interacted with ND to predict both vowel duration and hyperarticulation patterns. These findings indicate that lexical measures of a word’s difficulty and speakers’ online assessment of lexical intelligibility (based on a word’s visual presence or not) interactively influence phonetic modifications during communication with a real listener.
Recovery of coherent reflection from rough-surface scattered acoustic fields via the frequency-difference autoproduct
Authors: Joslyn Nicholas J. , Dowling David R.
Published: January 2022

The acoustic field reflected from a random rough surface loses coherence with the incident field in the Kirchhoff approximation as kh cos θ increases, where k is the incident field wavenumber, h is the root mean square roughness height, and θ is the incidence angle. Thus, for fixed rough-surface properties and incidence angle, a reflected field at lower wavenumber should retain more coherence. Recent results suggest that the frequency-difference autoproduct formed from complex acoustic field amplitudes at two nearby frequencies can recover acoustic information at the difference of those frequencies even when the difference frequency is below the recorded field's bandwidth. Herein analytical, computational, and experimental results are presented for the extent to which the frequency-difference autoproduct recovers coherence from randomly rough-surface-scattered constituent fields that have lost coherence. The analytical results, developed from the Kirchhoff approximation and formal ensemble averaging over randomly rough surfaces with Gaussian height distributions and Gaussian correlation functions, indicate that the coherence of the rough-surface-reflected frequency-difference autoproduct depends on the surface correlation length and Δkh cos θ, where Δk is the difference of the autoproduct's constituent field wavenumbers. These results compare favorably with Monte Carlo simulations of rough surface scattering, and with laboratory experiments involving long surface correlation lengths where 1 ≤kh cos θ≤ 3.
A systematic study on effects of calibration-waveguide geometry and least-squares formulation on ear-probe source calibrations
Authors: Nørgaard Kren Monrad , Hajicek Joshua J.
Published: January 2022

Measuring ear-canal absorbance and compensating for effects of the ear-canal acoustics on otoacoustic-emission measurements using an ear probe rely on accurately determining its acoustic source parameters. Using pressure measurements made in several rigid waveguides and models of their input impedances, a conventional calibration method estimates the ear-probe Thévenin-equivalent source parameters via a least-squares fit to an over-determined system of equations. Such a calibration procedure involves critical considerations on the geometry and number of utilized calibration waveguides. This paper studies the effects of calibration-waveguide geometry on achieving accurate ear-probe calibrations and measurements by systematically varying the lengths, length ratios, radii, and number of waveguides. For calibration-waveguide lengths in the range of 10–60 mm, accurate calibrations were generally obtained with absorbance measurement errors of approximately 0.02. Longer waveguides resulted in calibration errors, mainly due to coincident resonance frequencies among waveguides in the presence of mismatches between their assumed and actual geometries. The accuracy of calibrations was independent of the calibration-waveguide radius, except for an increased sensitivity of wider waveguides to noise. Finally, it is demonstrated how reformulating the over-determined system of equations to return the least-squares reflectance source parameters substantially reduces calibration and measurement errors.
Sparse Bayesian learning for wideband direction-of-arrival estimation via beamformer power outputs in a strong interference environment
Authors: Zhang Yahao , Yang Yixin , Yang Long , Wang Yong
Published: January 2022

Sparse Bayesian learning (SBL) offers a useful tool for wideband direction-of-arrival (DOA) estimation, but its performance is limited in the presence of strong interferences. To solve this problem, this letter attempts to extend the SBL to estimate DOAs via the beamformer power outputs (BPO) because the beamformer can efficiently suppress the interferences. A Bayesian probabilistic model effective for the BPO is proposed. Based on this, a BPO-based SBL method is put forward by adopting the variational Bayesian inference to estimate the DOAs from the BPO. Simulation and experimental results confirm the good performance of the proposed method.
Chlamydia Deficient in Plasmid-Encoded Glycoprotein 3 (pGP3) as an Attenuated Live Oral Vaccine
Authors: Zhou Zengzi , Tian Qi , Wang Luying , Zhong Guangming
Published: January 2022

Despite the extensive efforts, there is still a lack of a licensed vaccine against
Chlamydia trachomatis
in humans. The mouse genital tract infection with
Chlamydia muridarum
has been used to both investigate chlamydial pathogenic mechanisms and evaluate vaccine candidates due to the
C. muridarum
’s
ability to induce mouse hydrosalpinx.
C. muridarum
mutants lacking the entire plasmid or deficient in only the plasmid-encoded pGP3 are highly attenuated in inducing hydrosalpinx.
Coxiella burnetii Virulent Phase I and Avirulent Phase II Variants Differentially Manipulate Autophagy Pathway in Neutrophils
Authors: Kumaresan Venkatesh , Wang Juexin , Zhang Wendy , Zhang Yan , Xu Dong , Zhang Guoquan
Published: January 2022

Coxiella burnetii
is an obligate intracellular Gram-negative bacterium that causes Q fever in humans. The virulent
C. burnetii
Nine Mile phase I (NMI) strain causes disease in animal models, while the avirulent NM phase II (NMII) strain does not.
Staphylococcus aureus and Acinetobacter baumannii Inhibit Osseointegration of Orthopedic Implants
Authors: Choe Hyonmin , Tatro Joscelyn M. , Hausman Bryan S. , Hujer Kristine M. , Marshall Steve H. , Akkus Ozan , Rather Phillip N. , Lee Zhenghong , Bonomo Robert A. , Greenfield Edward M.
Published: January 2022

Bacterial infections routinely cause inflammation and thereby impair osseointegration of orthopedic implants.Acinetobacterspp., which cause osteomyelitis following trauma, on or off the battlefield, were, however, reported to cause neither osteomyelitis nor osteolysis in rodents. We therefore compared the effects ofAcinetobacterstrain M2 to those ofStaphylococcus aureusin a murine implant infection model. Sterile implants and implants with adherent bacteria were inserted in the femur of mice.
Signal Pathways for Regulation of Plant Alternative Oxidase Genes’ Expression
Authors: Garmash E. V.
Published: January 2022

This review deals with important issues in regulation of terminal alternative oxidase (AOX) of plant mitochondria, which are currently investigated and discussed. AOX ensures electron transport along the alternative nonphosphorylating cyanide-resistant pathway in mitochondrial ETC and plays an important role in the maintenance of redox balance in the cell and defense against stress. Principal results concerning AOX signaling were obtained in the works dealing with expression of the АОХ1а gene of Arabidopsis thaliana (AtAOX1a). Reports about АОХ expression in different plant species were analyzed. Mechanisms of transcriptional and posttranscriptional control over expression of АОХ genes were described. The role of some cis-regulatory elements of AtАОХ1а promoter and related transcription factors was considered. It was shown that transduction of the signal causing expression of АОХ genes may follow anterograde and retrograde pathways. Information about mitochondrial retrograde regulation of AOX and ROS-dependent and ROS-independent signal pathways of induction of АОХ expression is given. A hypothetic sequence of signal events of light induction of АОХ1а expression in wheat leaf cell in the course of greening was worked out. Interactions between AOX signaling and hormonal signal pathways, as well as induction of АОХ by the signals of plastid origin, were described. In conclusion, it was highlighted that AOX is integrated into the common signal pathway of the cell and acts as a target and a regulator of signal events.
Generation of cDC-like cells from human induced pluripotent stem cells via Notch signaling
Authors: Makino Kenichi , Long Mark D , Kajihara Ryutaro , Matsueda Satoko , Oba Takaaki , Kanehira Kazunori , Liu Song , Ito Fumito
Published: January 2022

Background

Dendritic cells (DCs) play critical roles in regulating the innate and adaptive immune responses, and have long been a major focus of cancer immunotherapy. Accumulating evidence suggests that conventional type 1 DCs (cDC1s) excel in cross-presentation of exogenous antigens on MHC-I molecules and induction of antitumor CD8+T cell immunity; however, obtaining large numbers of cDC1s is difficult. The use of reprogramming and differentiation technology is advantageous for obtaining unlimited numbers of autologous cDC1s especially for therapeutic interventions where repeated vaccinations are required. However, generation of cDC1s from human induced pluripotent stem cells (iPSCs) remains elusive.

Methods

Human iPSCs established from peripheral blood T cells and monocytes were differentiated to myeloid cells under on-feeder or feeder-free culture conditions in vitro. Phenotype, genomic and transcriptomic signature, and function of human iPSC-derived DCs were analyzed. The role of Notch signaling for the generation of HLA-DR+cells from human iPSCs was interrogated by a loss- and gain-of-function approach.

Results

Flow cytometric analyses and single-cell profiling of HLA-DR+cells revealed that human iPSCs gave rise to CD141+XCR1+CLEC9A+cells (cDC1s), CLEC4AhiCLEC10A–CD1c+cells (cDC2As), CLEC4AloCLEC10A+CD1c+cells (cDC2Bs), CD163–CD5+CD1c+cells (CD5+cDC2s), and AXL+SIGLEC6+cells (AS-DCs) on OP9 feeder cells expressing the Notch ligand delta-like 1 (OP9-DL1) while the majority of iPSC-derived cells differentiated on OP9 cells were CD163+CD5–CD1c+cells (DC3s) and monocytes. Plasmacytoid DCs were not differentiated from iPSCs on either OP9 or OP9-DL1 cells. Inhibition of Notch signaling during co-culture of iPSC-derived CD34+hematopoietic progenitor cells with OP9-DL1 cells abrogated generation of cDC1s, cDC2As, cDC2Bs, CD5+cDC2s, and AS-DCs but increased frequency of DC3s. Notch-activated human iPSC-derived XCR1+CLEC9A+HLA-DR+CD11c+cells exhibited similar gene expression profile with peripheral blood cDC1s. Human iPSC-derived DCs have phagocytic, T-cell proliferative, and cytokine-producing functions.

Conclusions

Our study demonstrates a critical role of Notch signaling in regulating developmental pathway of human cDCs. These findings provide insights into the future development of personalized treatment with unlimited numbers of autologous cDCs from human iPSCs.
Relational Gestalt approach to building a COVID-19 community of practice in a hospital setting
Authors: Denholm Justin T , Johnson Douglas , Denholm Gina C , Deligiannis Eva
Published: January 2022

Background

The COVID-19 pandemic has been highly disruptive in many work environments, particularly those related to direct provision of healthcare. Significant organisational change has been required at many levels, with attendant risks of both impaired service delivery and psychological impact on staff. Relational organisational Gestalt (ROG) is an approach that emphasises interpersonal connection about shared reality, which can be used in a variety of ways to support organisational change.

Methods

We established a community of practice in an acute hospital setting using ROG approaches during a COVID-19 pandemic wave. This group primarily consisted of senior medical staff redeployed to COVID-19 ward duties, who met daily for facilitated sessions centred around inpatient activities.

Results

Emerging group practices and outputs are described, including adjustments to group processes in response to situational need. A ROG approach was perceived as both effective in supporting rapid change in practice, and for providing psychological support for staff members.

Conclusions

ROG can be a useful and adaptive model for supporting staff and systems through times of change. Further exploration and evaluation of this approach in a variety of healthcare environments and applications will be valuable.
Combined balloon guide catheter, aspiration catheter, and stent retriever technique versus balloon guide catheter and stent retriever alone technique: a systematic review and meta-analysis
Authors: Teo Yao Neng , Sia Ching-Hui , Tan Benjamin Y Q , Mingxue Jing , Chan Bernard , Sharma Vijay Kumar , Makmur Andrew , Gopinathan Anil , Yang Cunli , Loh Stanley , Ng Sheldon , Ong Shao Jin , Teoh Hock-Luen , Rathakrishnan Rahul , Andersson Tommy , Arnberg Fabian , Gontu Vamsi Krishna , Lee Tsong-hai , Maus Volker , Meyer Lukas , Bhogal Pervinder , Spooner Oliver , Li Tony YW , Soh Rodney YH , Yeo Leonard LL
Published: January 2022

Background

The use of a combination of balloon guide catheter (BGC), aspiration catheter, and stent retriever in acute ischemic stroke thrombectomy has not been shown to be better than a stent retriever and BGC alone, but this may be due to a lack of power in these studies. We therefore performed a meta-analysis on this subject.

Methods

A systematic literature search was performed on PubMed, Scopus, Embase/Ovid, and the Cochrane Library from inception to October 20, 2021. Our primary outcomes were the rate of successful final reperfusion (Treatment in Cerebral Ischemia (TICI) 2c–3) and first pass effect (FPE, defined as TICI 2c–3 in a single pass). Secondary outcomes were 3 month functional independence (modified Rankin Scale score of 0–2), mortality, procedural complications, embolic complications, and symptomatic intracranial hemorrhage (SICH). A meta-analysis was performed using RevMan 5,4, and heterogeneity was assessed using the I2test.

Results

Of 1629 studies identified, five articles with 2091 patients were included. For the primary outcomes, FPE (44.9% vs 45.4%, OR 1.04 (95% CI 0.90 to 1.22), I2=57%) or final successful reperfusion (64.5% vs 68.6%, OR 0.98 (95% CI 0.81% to 1.20%), I2=85%) was similar between the combination technique and stent retriever only groups. However, the combination technique had significantly less rescue treatment (18.8% vs 26.9%; OR 0.70 (95% CI 0.54 to 0.91), I2=0%). This did not translate into significant differences in secondary outcomes in functional outcomes, mortality, emboli, complications, or SICH.

Conclusion

There was no significant difference in successful reperfusion and FPE between the combined techniques and the stent retriever and BGC alone groups. Neither was there any difference in functional outcomes, complications, or mortality.
Dicarbonyl anthracenes and phenanthrenes as singlet fission chromophores
Authors: James Dylan , Pradhan Ekadashi , Lee Seunghoon , Choi Cheol Ho , Zeng Tao
Published: January 2022

Singlet fission is a highly desired process in photovoltaic devices as it can significantly enhance photoelectric conversion efficiency. Exploitation of this process in photovoltaics is hindered by the lack of appropriate chromophores. We used mixed-reference spin-flip time-dependent density functional theory (TDDFT) to investigate five dicarbonyl anthracenes and phenanthrenes, with the purpose to design singlet fission chromophores. Two molecules were found to be promising candidates. For all the dicarbonyl molecules, the oxygen lone pair orbitals were found to be involved in the excited states that are relevant to singlet fission.
Kinetic study on pyridinolysis of aryl benzenesulfonates: factors governing regioselectivity and reaction mechanism
Authors: Um Ik-Hwan , Jung Yoon Jae , Dust Julian M.
Published: January 2022

A kinetic study is reported for reactions of 2,4-dinitrophenyl X-substituted-benzenesulfonates (1a–1f) and Y-substituted-phenyl benzenesulfonates (2a–2f) with Z-substituted-pyridines. The reactions proceed through S–O and C–O bond scissions competitively. The Yukawa–Tsuno plot for the reactions of 1a–1f with 4-oxypyridine (S–O bond fission) exhibits an excellent linearity. The Brønsted-type plot for the reactions of 2,4-dinitrophenyl benzenesulfonate (1d) with pyridines (S–O bond fission) is also linear with βnuc = 0.62. The Brønsted-type plot for the reactions of 2a–2f with 4-oxypyridines (S–O bond fission) is linear with βlg = –1.17. Thus, the reactions have been concluded to proceed through a concerted mechanism, in which leaving-group expulsion is significantly more advanced than bond formation between the electrophilic center and nucleophile at the transition state. The Hammett plot for the reactions of 1a–1f with 4-oxypyridine (C–O bond fission) exhibits scattered points with ρX = 0.98. The Brønsted-type plot for the reactions of 1d with Z-substituted-pyridines (C–O bond fission) results in an excellent linear correlation with βnuc = 0.38. Thus, the reactions (C–O bond fission) have been concluded to proceed through a stepwise mechanism with a Meisenheimer complex, in which expulsion of the leaving group occurs after the rate-determining step. Factors governing regioselectivity and reaction mechanism are discussed.
Biofilm streamer growth dynamics in various microfluidic channels
Authors: Zhang Jinchang , Dong Fulin , Liu Song , Zhang Duohuai , Wang Xiaoling
Published: January 2022

Biofilms are microbial colonies that are encapsulated in extracellular polymers secreted by cells through their proliferation and differentiation. Biofilms exist on solid surfaces, liquid surfaces, or in liquid media, where the growth of the bacterial biofilm is closely related to the velocity of the secondary flow, main flow, and geometry of the channel, which are difficult to measure in a natural fluid environment, making the study of the biofilm streamer growth process difficult. In this study, we used microfluidic channels made of polydimethylsiloxane to study the growth dynamics of Bacillus subtilis biofilm streamers. We observed that the biofilm streamer growth undergoes three stages with different growth characteristics. First, we found that the initial growth of the streamer is located at the position with the maximum value of P = secondary flow velocity × main flow velocity. Second, the biofilm underwent floating growth around the microcolumn obstacle. After the transition stage, the last growth stage includes two types because of the different attachment strengths and mechanical properties of the biofilm. Our research provides new insights into the formation and shedding of biofilm streamers in natural and industrial environments and helps us to better understand biofilm growth in fluid flow.
Bayes-Probabilistic-Based Fusion Method for Image Inpainting
Authors: Hudagi Manjunath R. , Soma Shridevi , Biradar Rajkumar L.
Published: January 2022

Image inpainting removes unwanted objects from the image, signifying the original image restoration. Even though several techniques are introduced for image inpainting, but still, there are several challenging issues associated with the conventional methods regarding data loss, which are effectively handled based on the proposed approach. In this paper, we propose an effective hybrid image inpainting method that is termed as ALGDKH, which is the hybridization of Ant Lion–Gray Wolf Optimizer (ALG)-based Markov random field (MRF) modeling, deep learning, [Formula: see text]-nearest neighbors (KNN) and the harmonic functions. The crack input image is forwarded as an input to Markov random field modeling to obtain image inpainting, where the MRF energy is minimized based on the ALG. Then, the same crack image is subjected to the Whale–MBO-based DCNN, KNN with Bhattacharya distance and Bi-harmonic function modules to obtain the inpainting results. Finally, the results from the proposed ALG-based Markov random field modeling, Whale–MBO-based DCNN, KNN with Bhattacharya distance and Bi-harmonic function modules are fused through Bayes-probabilistic fusion for the final inpainting results. The proposed method produces the maximal PSNR of 38.14[Formula: see text]dB, maximal SDME of 75.70[Formula: see text]dB and the maximal SSIM of 0.983.
REVISITING INFLATION-GROWTH NEXUS: AN ENDOGENOUS GROWTH MODEL WITH FINANCIAL FRICTIONS
Authors: CHANG FA-HSIANG , ZHANG LIN
Published: January 2022

This paper presents a new explanation of why the growth effect of inflation reported in the literature is an inverted-U relationship with considerations of lower bound on bank lending rates. We integrate a non-zero lower bound on the lending rate in the discussion and show the effect of inflation on optimal bank loan contracts. This paper believes that informational friction is a source of the negative relationship between inflation and growth when the loan rate constraint is non-binding. Besides, it finds out that once this loan rate constraint is binding, increasing inflation can reduce the real cost of financing capital investment and then contribute to growth. This paper also proves that the non-zero lower limit can only be reached at the low rate of inflation. It implies developing countries that are more likely to have low capital conversion efficiency and high transaction cost would hold a higher inflation-growth nexus than developed countries.
IMPACT OF COVID-19 ON VOLATILITY SPILLOVERS ACROSS INTERNATIONAL MARKETS: EVIDENCE FROM VAR ASYMMETRIC BEKK GARCH MODEL
Authors: ARFAOUI NADIA , YOUSAF IMRAN
Published: January 2022

This study contributes to the COVID-19 related literature in finance by examining asymmetric volatility spillover across stock, Bitcoin, gold and oil markets before and during the COVID-19 pandemic. Based on multivariate VAR asymmetric BEKK GARCH model, findings show that the interdependency across the examined markets intensified during the recent health crisis. Moreover, we find that oil market appears as major receivers of volatility spillovers, particularly from gold and stock market which is mostly the results of dramatic collapse of oil prices during the COVID-19 outbreak. We also document that gold exhibits a strong resilience during COVID-19 crisis, suggesting its potential hedging ability during uncertainty. As for asymmetric volatility spillover, findings show the highest sensitivity of oil and Bitcoin markets to gold and US stock markets. Our findings have important implications for investors, portfolio managers and policymakers.
THE EFFECTS OF SELECTED FINANCIAL RATIOS ON PROFITABILITY: AN EMPIRICAL ANALYSIS OF REAL ESTATE FIRMS IN VIETNAM
Authors: TRANG LE NGOC THUY , NHAN DO THI THANH , PHUONG DUNG NGUYEN THI , WONG WING-KEUNG
Published: January 2022

The paper examines the determinants of profitability of real estate companies by using panel data of Vietnamese listed companies on the Hanoi stock exchange (HNX) and Ho Chi Minh City stock exchange (HOSE) from 2007 to 2020. Profitability ratios are measured by return on assets (ROA) and return on equity (ROE). The results indicate that the cost on revenue ratio, debt-to-equity ratio and the crisis and COVID-19 pandemic are negatively correlated with firm profitability. Meanwhile, the sales to current assets ratio, money supply growth rate and economic growth rate (GDPG) provide a positive correlation with profitability. We find that firm size and equity to total assets have positive effects on ROA, while there is a negative relationship between equity to total assets and ROE, and not enough evidence to conclude how firm size affects ROE. The study thereby provides suggestions and recommendations for the administrators of the government, real estate companies and investors in Vietnam.
SYMMETRIC IMPACT OF EXCHANGE RATE VOLATILITY ON FOREIGN DIRECT INVESTMENT IN PAKISTAN: DO THE GLOBAL FINANCIAL CRISES AND POLITICAL REGIMES MATTER?
Authors: RAMZAN MUHAMMAD
Published: January 2022

Understanding currency fluctuations carries a high level of risk. A currency can slide or spike as a response of an economic indicators revelation or an unexpected political event, both of which are unforeseeable. As foreign investors become more optimistic about the country’s future, a healthier economy usually requires a strong currency. Therefore, it is necessary to assess the exchange rate volatility risk in the context of direct investment in order to develop preventive policy routes that would encourage foreign investors into the country. To this purpose, the autoregressive distributive least square (ARDL) technique has been employed to investigate the symmetric effect of exchange rate volatility on foreign direct investment (FDI) during global financial crises and political regimes from January 2000 to December 2018. In order to eliminate arbitrariness, the study uses the most accredited estimate of volatility, GARCH (1 1), as part of the re-estimation process. Besides this, the interaction has been studied under various regimes to see how the political environment affects foreign market participants’ expectations for future gains. The findings suggest that exchange rate volatility is adversely related to FDI and is a source of decreased net foreign investment in Pakistan. It also illustrates that during times of crises and apolitical regimes, Pakistan’s average FDI falls dramatically. The findings are extended to the context of Pakistan that has seen significant rupee volatility for the past few years. Our study recommends that policymakers should pursue exchange rate measures that promote exchange rate stability, which might assist to minimize risk of exchange rate volatility and so attract higher FDI. It is also crucial to formulate more sustainable investment methods that allow for efficient capital allocation during times of economic uncertainty.
Memory-Aware Functional IR for Higher-Level Synthesis of Accelerators
Authors: Schlaak Christof , Juang Tzung-Han , Dubach Christophe
Published: January 2022

Specialized accelerators deliver orders of a magnitude of higher performance than general-purpose processors. The ever-changing nature of modern workloads is pushing the adoption of Field Programmable Gate Arrays (FPGAs) as the substrate of choice. However, FPGAs are hard to program directly using Hardware Description Languages (HDLs). Even modern high-level HDLs, e.g., Spatial and Chisel, still require hardware expertise.

This article adopts functional programming concepts to provide a hardware-agnostic higher-level programming abstraction. During synthesis, these abstractions are mechanically lowered into a functional Intermediate Representation (IR) that defines a specific hardware design point. This novel IR expresses different forms of parallelism and standard memory features such as asynchronous off-chip memories or synchronous on-chip buffers. Exposing such features at the IR level is essential for achieving high performance.

The viability of this approach is demonstrated on two stencil computations and by exploring the optimization space of matrix-matrix multiplication. Starting from a high-level representation for these algorithms, our compiler produces low-level VHSIC Hardware Description Language (VHDL) code automatically. Several design points are evaluated on an Intel Arria 10 FPGA, demonstrating the ability of the IR to exploit different hardware features. This article also shows that the designs produced are competitive with highly tuned OpenCL implementations and outperform hardware-agnostic OpenCL code.
How Inclusive are We?
Authors: Bonifati Angela , Mior Michael J. , Naumann Felix , Sina Noack Nele
Published: January 2022

ACM SIGMOD, VLDB and other database organizations have committed to fostering an inclusive and diverse community, as do many other scientific organizations. Recently, different measures have been taken to advance these goals, especially for underrepresented groups. One possible measure is double-blind reviewing, which aims to hide gender, ethnicity, and other properties of the authors.

We report the preliminary results of a gender diversity analysis of publications of the database community across several peer-reviewed venues, and also compare women's authorship percentages in both single-blind and double-blind venues along the years. We also obtained a cross comparison of the obtained results in data management with other relevant areas in Computer Science.
Investigation of Alkyl Amine Substituted Quinone Derivatives for the Redox Flow Battery Applications in Acidic Medium
Authors: Sivanadanam Jagadeeswari , Murugan Raja , Khan Harun , Aidhen Indrapal Singh , Ramanujam Kothandaraman
Published: January 2022

2,5-bis((dimethylamino)methyl)benzene-1,4-diol (H2QDMA), a redox-active molecule and its derivatives are synthesised by a one-step chemical method using Mannich reaction has been explored as catholyte with vanadium (V2+/V3+) anolyte for aqueous redox flow battery applications. The solubility of H2QDMA was ∼ 0.75 M in 3 M H2SO4. H2QDMA showed one sharp redox peak at the formal potential 0.6 V ± vs Ag/AgCl, and it was stable for 100 continuous CV cycles without any appreciable change in colour. The battery delivered a discharge capacity of ∼ 2 Ah L−1, which faded with cycles. We have carried out a post cycle analysis of catholyte and anolyte to understand the origin of the capacity fading. Towards this, the oxidized form of H2QDMA, i.e., QDMA, was synthesized. The stability of QDMA in acidic solution was low, and the colour of the solution changed to intense brown with time. The UV–Visible spectrum and CV curves of the QDMA reflects the same behaviour as observed with the catholyte solution obtained post galvanostatic charge-discharge analysis. This study concluded that the QDMA undergoes faster chemical transformation, presumably through the Michael addition reaction process, compared to its participation in the desired electrochemical process.
Acoustic Response Characteristics of Lithium Cobaltate/Graphite Battery during Cycling
Authors: Sun Bo , Zhang Chuang , Liu Suzhen , Jin Liang , Yang Qingxin
Published: January 2022

Lithium-ion battery (LIB) has become an essential part of various advanced energy storage products due to their excellent performance, but the research on battery degradation is always challenging. The technology of using ultrasound to characterise the state of LIBs has unique advantages compared with other non-destructive testing methods. However, there have only been a few studies on the analysis of battery cycle performance through acoustic response results. In this paper, from the perspective of electrochemical-acoustic field coupling, the ultrasonic count is introduced to characterise the battery state. The acoustic response characteristics of the LIB in the cycling are analysed combined with the conventional acoustic metrics. Based on the continuous fatigue damage model, the acoustic count can infer partial change evolution of the overall effective Young’s modulus of the battery. This study shows that the characterisation of the battery state can provide further thinking for the mechanical evolution of the batteries.