bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nanoparticle-induced control (MWCNTs–TiO2) on grain size and tensile strength response and multi-response optimization on TIG welded joints
Authors: Muzamil Muhammad , Wu Jianjun , Akhtar Maaz , Azher Kashif , Majeed Arfan , Zhang Zengkun , Shazad Atif 
Published: April 2022

This study discusses the effectual variable parameters of multi-walled carbon nanotubes and titanium oxide (MWCNT–TiO2) contents and welding current in obtaining a response on mechanical behavior. The experimental work involved three levels of both parameters, which included 1, 1.5, and 2 wt.% of MWCNTs–TiO2 and 160, 180, and 200 A of current by forming a full design that represented a 32 (3 k) factorial model. The results of an analysis of variance (ANOVA) were critically employed to assess the variation between the variables and within their levels for approaching the significant combination of parameters. The joints welded with MWCNT–TiO2-coated fillers tendered a significant reduction in grain size (GS) along with high values of tensile strength (TS). From the ANOVA, it was determined that both the investigated parameters and their combined effect created a significant response for GS reduction and increment in TS. The presented empirical regression quadratic model was validated for the adequacy of the projected results that were shown to be acceptable with the experimental investigated data. In addition, the desirability function approach was applied for a multiple response optimization in yielding the desired responses of GS and TS and simultaneously providing an optimized set of process parameters. Thus, the function declared 1.5 wt.% MWCNT–TiO2 and 180 A as the optimized process set for delivering the maximum TS at the designated range of GS for this system.
Limits on primordial black holes detectability with Isatis: a BlackHawk tool
Authors: Auffinger Jérémy 
Published: April 2022

AbstractPrimordial black holes (PBHs) are convenient candidates to explain the elusive dark matter (DM). However, years of constraints from various astronomical observations have constrained their abundance over a wide range of masses, leaving only a narrow window open at $$10^{17}\,\mathrm{g} \lesssim M \lesssim 10^{22}\,$$

10
17

g
≲
M
≲

10
22

g for all DM in the form of PBHs. We reexamine this disputed window with a critical eye, interrogating the general hypotheses underlying the direct photon constraints. We review 4 levels of assumptions: (i) instrument characteristics, (ii) prediction of the (extra)galactic photon flux, (iii) statistical method of signal-to-data comparison and (iv) computation of the Hawking radiation rate. Thanks to , a new tool designed for the public Hawking radiation code , we first revisit the existing and prospective constraints on the PBH abundance and investigate the impact of assumptions (i)–(iv). We show that the constraints can vary by several orders of magnitude, advocating the necessity of a reduction of the theoretical sources of uncertainties. Second, we consider an “ideal” instrument and we demonstrate that the PBH DM scenario can only be constrained by the direct photon Hawking radiation phenomenon below $$M_{\mathrm{max}} \sim 10^{20}\,$$

M
max

∼

10
20

g. The upper part of the mass window should therefore be closed by other means.
Gravitational field of slightly deformed naked singularities
Authors: Toktarbay Saken , Quevedo Hernando , Abishev Medeu , Muratkhan Aray 
Published: April 2022

AbstractWe derive a particular approximate solution of Einstein equations, describing the gravitational field of a mass distribution that slightly deviates from spherical symmetry. The deviation is described by means of a quadrupole parameter that is responsible for the appearance of a curvature singularity, which is not covered by a horizon. We investigate the motion of test particles in the gravitational field of this naked singularity and show that the quadrupole parameter affects the properties of Schwarzschild trajectories. By investigating radial geodesics, we find that no effects of repulsive gravity are present. We interpreted this result as indicating that repulsive gravity is non-linear effect.
Complexity growth in Gubser–Rocha models with momentum relaxation
Authors: Babaei-Aghbolagh H. , Yekta Davood Mahdavian , Velni Komeil Babaei , Mohammadzadeh H. 
Published: April 2022

AbstractThe Einstein–Maxwell–Axion–Dilaton (EMAD) theories, based on the Gubser–Rocha (GR) model, are very interesting in holographic calculations of strongly correlated systems in condensed matter physics. Due to the presence of spatially dependent massless axionic scalar fields, the momentum is relaxed, and we have no translational invariance at finite charge density. It would be of interest to study some aspects of quantum information theory for such systems in the context of AdS/CFT where EMAD theory is a holographic dual theory. For instance, in this paper we investigate the complexity and its time dependence for charged AdS black holes of EMAD theories in diverse dimensions via the complexity equals action (CA) conjecture. We will show that the growth rate of the holographic complexity violates Lloyd’s bound at finite times. However, as shown at late times, it depends on the strength of the momentum relaxation and saturates the bound for these black holes.
Grand Theories or Design Guidelines? Perspectives on the Role of Theory in Computing Education Research
Authors: Tedre Matti , Pajunen John 
Published: April 2022

A rich body of empirically grounded results and a solid theory base have often been viewed as signs of a mature discipline. Many disciplines have frequently debated what they should accept as legitimate kinds of theories, the proper roles of theory, and appropriate reference disciplines. Computing education research (CER) in particular has seen a growing number of calls for the development of domain-specific theories for CER, an adaptation of theories from other fields, and engagement with theory-based experimental and predictive research in CER. Many of those calls share the same concerns and aims, yet they use very different vocabulary and lack a consensus over an essential concept: theory.This article presents sticking points and trouble spots in CER’s theory debates and presents a number of suggestions and ways forward. Firstly, by slightly shifting towards a model-based view of science, CER can avoid centuries of conceptual baggage related to the concept of theory. Secondly, insofar as fields like design, engineering, and social science are considered to be legitimate parts of CER, the role of theory in many CER studies needs to be judged by the criteria of the philosophy of engineering, technology, and social science, not the philosophy of (natural) science. Thirdly, instead of force-fitting elements of ill-suited research paradigms from other disciplines, the philosophy of CER should focus on building a consensus on CER’s own paradigm and describing the field’s relationship with theory in CER’s own terms.
A Sociocultural Perspective on Computer Science Capital and Its Pedagogical Implications in Computer Science Education
Authors: Vrieler Tina , Salminen-Karlsson Minna 
Published: April 2022

The aim of this conceptual article is to provide a framework and a lens for educators in diversifying and making CS education more inclusive. In this article, we conceptualize the notion of computer science capital (CSC), which extends Bourdieu’s sociological theory of capital and Archer et al.’s work on “science capital.” The CSC concept was developed by contrasting the concept of science capital with a literature review on key factors affecting students’ aspirations in CS. We argue that there is a need to distinguish between science capital and CSC, because the types of capital that are considered legitimate vary between the field of natural science and computer science. The CSC concept uses a sociocultural perspective on learning and can be understood as a form of symbolic capital that is influential in facilitating students’ possibility to fully participate in, engage with, and form aspirations in CS. The CSC concept consists of three main components, each with associated subcomponents. We believe our CSC framework, along with the self-reflection prompts included in this article, will offer support for reflections for educators in their daily pedagogical work. By taking students’ various levels of social and cultural capital into consideration, educators can plan didactic activities with a focus to strengthen students’ various types of capital. This includes reflection on how implicit and explicit norms, beliefs, thoughts, expectations, values, and ideas can affect the pedagogical practices and ultimately the students. Only when we are reflective about our teaching practices can we be better positioned to construct a more inclusive teaching and learning environment.
The Different Types of Contributions to Knowledge (in CER): All Needed, But Not All Recognised
Authors: Draper Steve , Maguire Joseph 
Published: April 2022

The overall aim of this article is to stimulate discussion about the activities within CER, and to develop a more thoughtful and explicit perspective on the different types of research activity within CER, and their relationships with each other. While theories may be the most valuable outputs of research to those wishing to apply them, for researchers themselves there are other kinds of contributions important to progress in the field. This is what relates it to the immediate subject of this special journal issue on theory in CER. We adopt as our criterion for value “contribution to knowledge”.

This article’s main contributions are

–
A set of 12 categories of contributions which together indicate the extent of this terrain of contributions to research.

–
Leading into that is a collection of ideas and misconceptions which are drawn on in defining and motivating “ground rules”, which are hints and guidance on the need for various often neglected categories. These are also helpful in justifying some additional categories which make the set as a whole more useful in combination.

These are followed by some suggested uses for the categories, and a discussion assessing how the success of the article might be judged.
Finding real bugs in big programs with incorrectness logic
Authors: Le Quang Loc , Raad Azalea , Villard Jules , Berdine Josh , Dreyer Derek , O'Hearn Peter W. 
Published: April 2022

Incorrectness Logic (IL) has recently been advanced as a logical theory for compositionally proving the presence of bugs—dual to Hoare Logic, which is used to compositionally prove their absence. Though IL was motivated in large part by the aim of providing a logical foundation for bug-catching program analyses, it has remained an open question: is IL useful only retrospectively (to explain existing analyses), or can it actually be useful in developing new analyses which can catch real bugs in big programs?
In this work, we develop Pulse-X, a new, automatic program analysis for catching memory errors, based on ISL, a recent synthesis of IL and separation logic. Using Pulse-X, we have found 15 new real bugs in OpenSSL, which we have reported to OpenSSL maintainers and have since been fixed. In order not to be overwhelmed with potential but false error reports, we develop a compositional bug-reporting criterion based on a distinction between latent and manifest errors, which references the under-approximate ISL abstractions computed by Pulse-X, and we investigate the fix rate resulting from application of this criterion. Finally, to probe the potential practicality of our bug-finding method, we conduct a comparison to Infer, a widely used analyzer which has proven useful in industrial engineering practice.
Hardware Trojan Detection Using Unsupervised Deep Learning on Quantum Diamond Microscope Magnetic Field Images
Authors: Ashok Maitreyi , Turner Matthew J. , Walsworth Ronald L. , Levine Edlyn V. , Chandrakasan Anantha P. 
Published: April 2022

This article presents a method for hardware trojan detection in integrated circuits. Unsupervised deep learning is used to classify wide field-of-view (4 × 4 mm
2
), high spatial resolution magnetic field images taken using a Quantum Diamond Microscope (QDM). QDM magnetic imaging is enhanced using quantum control techniques and improved diamond material to increase magnetic field sensitivity by a factor of 4 and measurement speed by a factor of 16 over previous demonstrations. These upgrades facilitate the first demonstration of QDM magnetic field measurement for hardware trojan detection. Unsupervised convolutional neural networks and clustering are used to infer trojan presence from unlabeled data sets of 600 × 600 pixel magnetic field images without human bias. This analysis is shown to be more accurate than principal component analysis for distinguishing between field programmable gate arrays configured with trojan-free and trojan-inserted logic. This framework is tested on a set of scalable trojans that we developed and measured with the QDM. Scalable and TrustHub trojans are detectable down to a minimum trojan trigger size of 0.5% of the total logic. The trojan detection framework can be used for golden-chip-free detection, since knowledge of the chips’ identities is only used to evaluate detection accuracy.
The Relevance of Interventional Time and Clinical Outcomes in Patients with NSTEMI Based on the GRACE Score
Authors: Wang Ji-Xiang , Gao Jing , Xiao Jian-Yong , Gao Ming-Dong , Zhang Nan , Lu Peng-Ju , Liu Yin 
Published: April 2022

Objective. To investigate the relevance between interventional time and clinical outcomes in non-ST-elevation myocardial infarction (NSTEMI) patients of different risk stratifications, which were divided into different groups according to GRACE scores and the time from admission to percutaneous coronary intervention (PCI). Method. Patients were grouped according to the GRACE score and the time from admission to intervention therapy. The Cox multivariate risk regression model was used to analyze the correlation between the GRACE score and the time from admission to intervention therapy with major adverse cardiovascular events (MACEs). Cox interactive item regression was also used to investigate the correlation between the time of intervention therapy and GRACE risk stratification with clinical outcomes and to evaluate the efficacy of intervention therapy in different risk stratifications of patients with NSTEMI. Results. Interactive item Cox regression analysis and subgroup analysis show that high-risk NSTEMI patients with a GRACE

score
>
140

points and the time from admission to

intervention
<
24

h

(

p
=
0.0004

) and 24–72 h (

p
=
0.0143

) have interactive effects on the impact of the MACE event with the reference of intervention

time
>
72

h

and GRACE

score
<
108

points. The time from admission to

intervention
<
24

h

is an independent protective factor for the occurrence of MACE events (

HR
=
0.166

, 95% CI 0.052-0.532,

p
=
0.0025

). Middle-risk patients with NSTEMI with a GRACE score of 109–140 points and the time from admission to

intervention
<
24

h

(

p
=
0.0370

) and 24–72 h (

p
=
0.0471

) have an interactive effect on the impact of MACE. The time from admission to

intervention
>
72

h

is an independent protective factor for the occurrence of MACE (

HR
=
0.201

, 95% CI 0.045-0.897,

p
=
0.0355

). Conclusion. The time from admission to

intervention
<
24

h

could effectively reduce the risk of MACE events within 1 year in high-risk patients with NSTEMI (GRACE

score
>
140

points); the time from admission to

intervention
>
72

h

can reduce the risk of MACE events within 1 year in low-risk patients with NSTEMI (GRACE

score
≤
108

points).
Clinical Characteristics and Risk Factors for Pulmonary Infection in Emergency ICU Patients
Authors: Zhang Yan , Cao Hui , Gong Xiang , Wu Yang , Gu Peng , Kong Linling , Wu Limeng , Xing Jiali 
Published: April 2022

Background. Pulmonary infection in the emergency ICUs increases patient morbidity, hospital stay, treatment costs, and the risk of related adverse events. Methods. This study included 695 patients admitted to our emergency ICU between December 2019 and March 2021. Medical records of emergency ICU patients were reviewed to collect their clinical data, including antibiotic use, history of tracheostomy, history of mechanical ventilation, presence or absence of underlying disease, history of smoking, alcohol consumption, age, gender, and history of shock. Bacterial cultures were performed. The incidence, main clinical features, main pathogens, and risk factors of pulmonary infection in emergency ICU were analyzed. Results. In this study, 69 of the 695 emergency ICU patients (9.93%) developed pulmonary infection. The main clinical features of patients with pulmonary infection included cough and expectoration (97.10%), shortness of breath and chest tightness (95.65%), leukocyte elevation (69.57%), confusion (31.88%), drowsiness (28.99%), persistent fever (27.54%), and nausea and vomiting (10.14%). The main pathogenic bacteria in those with pulmonary infection included Klebsiella pneumoniae (62.32%), Pseudomonas aeruginosa (49.28%), Streptococcus pneumoniae (21.74%), Staphylococcus aureus (39.13%), Candida albicans (7.25%), Pneumococcus pneumoniae (15.95%), Pseudomonas aeruginosa (24.64%), and lung diplococcus inflammatory (13.04%). Univariate analysis showed that there were no significant differences in the occurrence of pulmonary infection with regard to sex, smoking, and alcohol consumption, but there were significant differences with regard to age, basic disease, invasive surgery, and shock. Logistic regression analysis confirmed that

age
≥
80

years

, invasive surgery, shock, and

basic

diseases
≥
2

were important risk factors for pulmonary infection in emergency ICU patients. Conclusion. Considering the clinical features and risk factors for pulmonary infection in the emergency ICU, preventive and control measures are required to minimize its occurrence and ensure good outcomes.
Genome-Protective Topoisomerase 2a-Dependent G2 Arrest Requires p53 in hTERT-Positive Cancer Cells
Authors: Lockwood Nicola , Martini Silvia , Lopez-Pardo Ainara , Deiss Katharina , Segeren Hendrika A. , Semple Robert K. , Collins Ian , Repana Dimitra , Cobbaut Mathias , Soliman Tanya , Ciccarelli Francesca , Parker Peter J. 
Published: April 2022

Abstract

Topoisomerase 2a (Topo2a)-dependent G2 arrest engenders faithful segregation of sister chromatids, yet in certain tumor cell lines where this arrest is dysfunctional, a PKCε-dependent failsafe pathway can be triggered. Here we elaborate on recent advances in understanding the underlying mechanisms associated with this G2 arrest by determining that p53–p21 signaling is essential for efficient arrest in cell lines, in patient-derived cells, and in colorectal cancer organoids. Regulation of this p53 axis required the SMC5/6 complex, which is distinct from the p53 pathways observed in the DNA damage response. Topo2a inhibition specifically during S phase did not trigger G2 arrest despite affecting completion of DNA replication. Moreover, in cancer cells reliant upon the alternative lengthening of telomeres (ALT) mechanism, a distinct form of Topo2a-dependent, p53-independent G2 arrest was found to be mediated by BLM and Chk1. Importantly, the previously described PKCε-dependent mitotic failsafe was engaged in hTERT-positive cells when Topo2a-dependent G2 arrest was dysfunctional and where p53 was absent, but not in cells dependent on the ALT mechanism. In PKCε knockout mice, p53 deletion elicited tumors were less aggressive than in PKCε-replete animals and exhibited a distinct pattern of chromosomal rearrangements. This evidence suggests the potential of exploiting synthetic lethality in arrest-defective hTERT-positive tumors through PKCε-directed therapeutic intervention.

Significance:
The identification of a requirement for p53 in stringent Topo2a-dependent G2 arrest and engagement of PKCε failsafe pathways in arrest-defective hTERT-positive cells provides a therapeutic opportunity to induce selective synthetic lethality.
Tumor Purity in Preclinical Mouse Tumor Models
Authors: Qian Wubin , Chen Xiaobo , Sheng Yanghui , Zhang Likun , Wang Jingjing , Song Zhenzhen , Li Qi-Xiang , Guo Sheng 
Published: April 2022

Tumor biology is determined not only by immortal cancer cells but also by the tumor microenvironment consisting of noncancerous cells and extracellular matrix, together they dictate the pathogenesis and response to treatments. Tumor purity is the proportion of cancer cells in a tumor. It is a fundamental property of cancer and is associated with many clinical features and outcomes. Here we report the first systematic study of tumor purity in patient-derived xenograft (PDX) and syngeneic tumor models using next-generation sequencing data from &gt;9,000 tumors. We found that tumor purity in PDX models is cancer specific and mimics patient tumors, with variation in stromal content and immune infiltration influenced by immune systems of host mice. After the initial engraftment, human stroma in a PDX tumor is quickly replaced by mouse stroma, and tumor purity then stays stable in subsequent transplantations and increases only slightly by passage. Similarly, in syngeneic mouse cancer cell line models, tumor purity also turns out to be an intrinsic property with model and cancer specificities. Computational and pathology analysis confirmed the impact on tumor purity by the diverse stromal and immune profiles. Our study deepens the understanding of mouse tumor models, which will enable their better and novel uses in developing cancer therapeutics, especially ones targeting tumor microenvironment.Significance:PDX models are an ideal experimental system to study tumor purity because of its distinct separation of human tumor cells and mouse stromal and immune cells. This study provides a comprehensive view of tumor purity in 27 cancers in PDX models. It also investigates tumor purity in 19 syngeneic models based on unambiguously identified somatic mutations. It will facilitate tumor microenvironment research and drug development in mouse tumor models.