bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of the COVID-19 pandemic on abortions and births in Sweden: a mixed-methods study
Authors: Rydelius Johanna , Edalat Mina , Nyman Viola , Jar-Allah Tagrid , Milsom Ian , Hognert Helena
Published: February 2022

Introduction

Although considered an essential service by the WHO, there are indications that access to induced abortion care has been restricted during the COVID-19 pandemic.

Objectives

To investigate if the number of induced abortions and ongoing pregnancies changed during the first pandemic wave of COVID-19 in 2020 compared with recent years prior to the pandemic and explore possible reasons for the findings.

Design

Convergent parallel mixed-methods design. Collection of quantitative data from the Swedish National Board of Health and Welfare and the Swedish Pregnancy Register, and qualitative data from interviews.

Setting and time period

National data on abortions (January 2018–June 2020) and births (January 2018–March 2021). Interviews performed at the main abortion clinic, Gothenburg, Sweden, in June 2020.

Participants

All women aged 15–44 years living in Sweden 2018–2020, approximately 1.9 million. 15 women who sought abortion were interviewed.

Primary and secondary outcome measures

Number of abortions and births/1000 women aged 15–44 years. Themes and subthemes identified from interviews.

Results

The number of abortions and ongoing pregnancies did not change significantly during the study period compared with before the pandemic started. Interview themes identified were the following: meeting with abortion care during the COVID-19 pandemic (availability, and fear of being infected and infecting others); and the impact of the COVID-19 pandemic on the abortion decision (to catch COVID-19 during pregnancy, feelings of loneliness and isolation, and social aspects).

Conclusions

This study shows that the number of abortions and ongoing pregnancies remained unchanged during the first wave of the COVID-19 pandemic in 2020 in Sweden compared with before the start of the pandemic. Abortion-seeking women did not hesitate to proceed with the abortion. The women expressed a number of fears concerning both availability of care and their health, which could have been properly addressed by the authorities.
Effect of triclosan-coated sutures for abdominal wound closure on the incidence of abdominal wound dehiscence: a protocol for an individual participant data meta-analysis
Authors: Timmer Allard S , Wolfhagen Niels , Pianka Frank , Knebel Phillip , Justinger Christoph , Stravodimos Christos , Ichida Kosuke , Rikiyama Toshiki , Baracs József , Vereczkei András , Gianotti Luca , Ruiz-Tovar Jaime , Hernández Artur M , Nakamura Toru , Dijkgraaf Marcel G W , Boermeester Marja A , de Jonge Stijn W
Published: February 2022

Introduction

Acute abdominal wound dehiscence (AWD) or burst abdomen is a severe complication after abdominal surgery with an incidence up to 3.8%. Surgical site infection (SSI) is the biggest risk factor for the development of AWD. It is strongly suggested that the use of triclosan-coated sutures (TCS) for wound closure reduces the risk of SSI. We hypothesise that the use of TCS for abdominal wound closure may reduce the risk of AWD. Current randomised controlled trials (RCTs) lack power to investigate this. Therefore, the purpose of this individual participant data meta-analysis is to evaluate the effect of TCS for abdominal wound closure on the incidence of AWD.

Methods and analysis

We will conduct a systematic review of Medline, Embase and Cochrane Central Register of Controlled Trials for RCTs investigating the effect of TCS compared with non-coated sutures for abdominal wound closure in adult participants scheduled for open abdominal surgery. Two independent reviewers will assess eligible studies for inclusion and methodological quality. Authors of eligible studies will be invited to collaborate and share individual participant data. The primary outcome will be AWD within 30 days after surgery requiring reoperation. Secondary outcomes include SSI, all-cause reoperations, length of hospital stay and all-cause mortality within 30 days after surgery. Data will be analysed with a one-step approach, followed by a two-step approach. In the one-step approach, treatment effects will be estimated as a risk ratio with corresponding 95% CI in a generalised linear mixed model framework with a log link and binomial distribution assumption. The quality of evidence will be judged using the Grading of Recommendations Assessment Development and Evaluation approach.

Ethics and dissemination

The medical ethics committee of the Amsterdam UMC, location AMC in the Netherlands waived the necessity for a formal approval of this study, as this research does not fall under the Medical Research involving Human Subjects Act. Collaborating investigators will deidentify data before sharing. The results will be submitted to a peer-reviewed journal.

PROSPERO registration number

CRD42019121173.
Impact of interankle blood pressure difference on major adverse cardiovascular events in cryptogenic stroke patients without peripheral artery disease: a retrospective cohort study
Authors: Han Minho , Baik Minyoul , Kim Young Dae , Choi Junghye , Seo Kangsik , Park Eunjeong , Heo Ji Hoe , Nam Hyo Suk
Published: February 2022

Objective

We investigated whether interankle blood pressure difference (IAND) can predict major adverse cardiovascular events (MACEs) in patients with cryptogenic stroke (CS) without peripheral artery disease (PAD).

Design

A retrospective cohort study.

Setting

Retrospective medical record data of patients with first-ever acute cerebral infarction who were admitted between 1 January 2007 and 31 July 2013.

Participants

CS patients admitted within 7 days of symptom onset were included.

Outcome measures

MACEs were defined as stroke recurrence, myocardial infarction occurrence, or death. Survival analyses were conducted using the Kaplan-Meier method and Cox regression analysis.

Methods

Consecutive CS patients without PAD who underwent ankle–brachial index (ABI) measurements were enrolled. PAD was defined if a patient had an ABI of <0.90 or a history of angiographically confirmed PAD. Systolic and diastolic IANDs were calculated as follows: right ankle blood pressure—left ankle blood pressure.

Results

A total of 612 patients were enrolled and followed up for a median 2.6 (interquartile range, 1.0–4.3) years. In the Cox regression analysis, systolic and diastolic IANDs ≥15 mm Hg were independently associated with MACEs in CS patients without PAD (hazard ratio (HR) 2.115, 95% confidence interval (CI) 1.230 to 3.635 and HR 2.523, 95% CI 1.086 to 5.863, respectively). In the subgroup analysis, systolic IAND ≥15 mm Hg was independently associated with MACEs in older patients (age ≥65 years) (HR 2.242, 95% CI 1.170 to 4.298) but not in younger patients (age <65 years).

Conclusions

Large IAND is independently associated with the long-term occurrence of MACEs in patients with CS without PAD. In particular, the association between IAND and MACEs is only valid in elderly patients.
Does the presence of general practitioners in emergency departments affect quality and safety in English NHS hospitals? A retrospective observational study
Authors: Gaughan James , Liu Dan , Gutacker Nils , Bloor Karen , Doran Tim , Benger Jonathan Richard
Published: February 2022

Objectives

Emergency departments (EDs) in NHS hospitals in England have faced considerable increases in demand over recent years. Most hospitals have developed general practitioner services in emergency departments (GPEDs) to treat non-emergency patients, aiming to relieve pressure on other staff and to improve ED efficiency and patient experience. We measured the impact of GPED services on patient flows, health outcomes and ED workload.

Design

Retrospective observational study. Differences in GPED service availability across EDs and time of day were used to identify the causal effect of GPED, as patients attending the ED at the same hour of the day are quasi-randomly assigned to treatment or control groups based on their local ED’s service availability.

Participants

Attendances to 40 EDs in English NHS hospitals from April 2018 to March 2019, 4 441 349 observations.

Primary and secondary outcomes measured

Outcomes measured were volume of attendances, ‘non-urgent’ attendances, waiting times over 4 hours, patients leaving without being treated, unplanned reattendances within 7 days, inpatient admissions and 30-day mortality.

Results

We found a small, statistically significant reduction in unplanned reattendances within 7 days (OR 0.968, 95% CI 0.948 to 0.989), equivalent to 302 fewer reattendances per year for the average ED. The clinical impact of this was judged to be negligible. There was no detectable impact on any other outcome measure.

Conclusions

We found no adverse effects on patient outcomes; neither did we find any evidence of the hypothesised benefits of placing GPs in emergency settings beyond a marginal reduction in reattendances that was not considered clinically significant.
Joint associations of fresh fruit intake and physical activity with glycaemic control among adult patients with diabetes: a cross-sectional study
Authors: Wu Jie , Hong Xin , Wang Chenchen , Qi Shengxiang , Ye Qing , Qin Zhenzhen , Zhou Hairong , Li Chao , Wang Weiwei , Zhou Nan
Published: February 2022

Objective

To investigate the joint associations of fresh fruit intake and physical activity with glycaemic control in adult patients with diabetes mellitus (DM).

Design

It was an observational study involving adult patients with DM through a face-to-face questionnaire survey, physical measurements and laboratory examinations. Data were analysed by introducing a generalised linear mixed model, and a significant difference was set at p<0.05.

Setting

Nanjing, Jiangsu, China.

Participants

A total of 5663 adult patients with DM from the 2017 Nanjing Chronic Disease and Risk Factor Surveillance were recruited.

Results

Based on the food frequency questionnaire, fresh fruit intake was classified as ‘not eat’, ‘1~99 g/day’ and ‘≥100 g/day’. Physical activity level was calculated based on the data of Global Physical Activity Questionnaire and classified into insufficient physical activity (<600 MET-min/week) and sufficient physical activity (≥600 MET-min/week). The likelihood of glycaemic control in adult patients with DM with fresh fruit intake ≥100 g/day was 37.8% (OR: 1.378; 95% CI: 1.209 to 1.571) higher than those with fresh fruit intake <100 g/day, which was 26% (OR: 1.260; 95% CI: 1.124 to 1.412) higher in adult patients with DM with sufficient physical activity than those with insufficient physical activity. Adult patients with DM with fresh fruit intake ≥100 g/day and sufficient physical activity presented the greatest likelihood of glycaemic control (OR: 1.758; 95% CI: 1.471 to 2.102) compared with those with both fresh fruit intake <100 g/day and insufficient physical activity.

Conclusions

Fresh fruit intake ≥100 g/day combined with sufficient physical activity is associated with a significantly higher likelihood of glycaemic control in adult patients with DM.
Type 1 interferon status in systemic lupus erythematosus: a longitudinal analysis
Authors: Northcott Melissa , Jones Sarah , Koelmeyer Rachel , Bonin Julie , Vincent Fabien , Kandane-Rathnayake Rangi , Hoi Alberta , Morand Eric
Published: February 2022

Objectives

Type 1 interferon (IFN) is key to the pathogenesis of SLE, evidenced by the expression of IFN-stimulated genes (ISGs) in most patients, but the clinical utility of serial ISG assessment remains unknown. With the emergence of IFN-blocking drugs, we aimed to examine IFN status in relation to clinical findings longitudinally to provide insights into the value of testing ISG levels over time.

Methods

Clinical data and whole blood were collected prospectively on adult patients with SLE from a single tertiary lupus centre. IFN status was measured using a panel of ISGs.

Findings

729 samples were analysed from 205 patients. At baseline, 62.9% of patients were IFN high, 30.2% IFN low and 6.8% borderline. 142 patients had multiple samples collected, and 87.3% of these demonstrated stable ISG status over time. In longitudinal follow-up, IFN high patients had higher activity in multiple organ domains and spent less time in Lupus Low Disease Activity State, but IFN score did not correlate with SLE Disease Activity Index in individual patients. In the small subset of patients who had large fluctuations in ISG across the observation period, most had high-dose glucocorticoids that correlated with ISG suppression. However, low-moderate-dose glucocorticoids did not suppress ISG expression.

Conclusion

Although IFN high status is associated with indicators of more severe SLE, in the majority of patients, ISGs are stable across time and do not correlate with disease activity. Changes in ISG expression may be seen with high-dose, but not routine dose, glucocorticoid exposure. These findings suggest baseline but not serial ISG measurement may be of value in the management of SLE.
Quantum entanglement and axion physics
Authors: Nicolaidis A.
Published: February 2022

The axion particle is the outcome of the proposed Peccei–Quinn mechanism for solving the strong CP problem. Axion is also a popular dark matter candidate. Thus, there is an increased interest in establishing its existence. Axions couple to two photons and most experiments search for the transition of an axion into a photon, in the presence of a magnetic field. In our study, we examine the coupling of the axion into a pair of entangled photons. The presence of a magnetic field changes the polarization correlations of the entangled photons, thus offering an unambiguous signature for axion existence.
Nonlinear Dynamics and Control of Time-Delay Supercavitating Vehicle
Authors: Bai Xue , Li Qinglong , Xu Ming
Published: February 2022

This paper investigates the nonlinear dynamical behaviors of a time-delayed supercavitating vehicle system varying with the system parameters, and proposes control strategies to stabilize the trajectory. A simplified dynamical model of the supercavitating vehicle is firstly constructed and then analyzed on its local and global stability in terms of different parameter values and initial conditions. Due to the forces resulting from the fins and the afterbody plane causing one of the system parameters to become a piecewise constant function of position, the system is described as a linear switched one with time delay. Both theoretical analysis and numerical simulations are adopted to describe the system behaviors. Several special phenomena such as bifurcations, deviation behaviors and period-doubling processes emerging from the system for a given set of parameters are discussed in detail in this paper. Besides, the equilibrium and chaotic solutions are accurately located by plotting the Lyapunov exponent map. Chaotic attractors present different strange forms with the variation of the parameters. Finally, based on the system’s global property, the control and anti-control strategies are proposed to stabilize the system or generate desirable chaos and it is shown that the system can be controlled by selecting appropriate control parameters.
Transition to Chaos in Five-Dimensional Porous-Medium Thermal-Hydrodynamic Model with Low Prandtl Number
Authors: Beljadid Abdelaziz , Joundy Youssef , Rouah Hamza , Taik Ahmed
Published: February 2022

In this paper, we investigate the transition to a chaotic regime of thermal convection in a five-dimensional model with low Prandtl number in a porous medium. The mathematical formulation of the model includes the heat equation coupled with the equations of motion under the Boussinesq–Darcy approximation. A system of five ordinary differential equations is derived using a spectral method. This system is solved numerically by using the fourth-order Runge–Kutta method. The results show that from a subcritical value of the Rayleigh number, a transition from steady convection to chaos via a Hopf bifurcation produces a limit cycle which can be associated with a homoclinic explosion. Furthermore, we find that for certain values of Rayleigh number and shape parameter which measures the ratio between the dimensions of the computational domain, the transition from periodic oscillatory convection to chaotic convection can occur via a period-doubling.
Stability and Bifurcation Analysis for a Nitrogen-Fixing Evolutionary Game with Environmental Feedback and Discrete Delays
Authors: Cheng Haihui , Meng Xinzhu , Hayat Tasawar , Hobiny Aatef , Zhang Tonghua
Published: February 2022

In this paper, a nitrogen fixation game system with two time delays under nitrogen limitation is investigated. Firstly, we discuss the existence and local stability of the equilibrium points for the nondelay system. Then the nitrogen fixation delay and strategy-dependent delay are used as bifurcation parameters to analyze the local stability and the Hopf bifurcation. In addition, we obtain the direction of Hopf bifurcation, the change of the period for periodic solution and the stability of periodic solution via center manifold theory and normal form method. Finally, numerical simulation is employed to visualize the theoretical analysis results and we find that the nitrogen fixation strategy is the dominant strategy when the values of the two time delays are large enough. This study promotes the investigation of the effects of two time delays on the dynamics of evolutionary games with environmental feedback, especially on stability and bifurcation.
3D Localization and Error Minimization in Underwater Sensor Networks
Authors: Sah Dinesh Kumar , Nguyen Tu N. , Kandulna Manjusha , Cengiz Korhan , Amgoth Tarachand
Published: February 2022

Wireless sensor networks (WSNs) consist of nodes distributed in the region of interest (ROI) that forward collected data to the sink. The node’s location plays a vital role in data forwarding to enhance network efficiency by reducing the packet drop rate and energy consumption. WSN scenarios, such as tracking, smart cities, and agriculture applications, require location details to accomplish the objective. Assuming a 3D application space, a combination of received signal strength (RSS) and time of arrival (TOA) can be helpful for reliable range estimation of nodes. Notably, the anchor node can minimize localization error for non-line-of-sight (NLOS) signals. We proposed an error minimization protocol for localization of the sensor node, assuming that the anchor node’s location is known prior and can limit the receiving signal in LOS, single, or twice reflection. We start to exploit the sensor node’s geometrical relationship and the anchor node for LOS and NLOS signals and address misclassification. We started initially from the erroneous node position, bound its volume in 3D space, and reduced volume with each iteration following the constraint. Our simulation result outperforms the traditional methods on many occasions, such as boundary volume and computational complexity.
Traffic Classification in Underwater Networks Using SDN and Data-Driven Hybrid Metaheuristics
Authors: Pradhan B. , Srivastava Gautam , Roy D. S. , Reddy K. H. K. , Lin Jerry Chun-Wei
Published: February 2022

Software-Defined Networks
(
SDNs
), with their segregated data and control planes, has proved to be capable of managing massive amounts of data by leveraging distributed information available across the network for informed decision-making at the network controller. However, with the proliferation of next-generation, real-time
Internet of Things
(
IoT
) applications that vary greatly in terms of data frequency and volumes, data traffic classification can substantially assist SDN controllers toward efficient routing and traffic engineering decisions. Existing works on network classification are limited by their application-centric nature, thus overlooking the key criterion for real-time IoT applications, namely,
Quality of Service
(
QoS
). In this article, we focus on augmenting SDN controllers’ decision-making capacity and Underwater Sensor Networks with machine learning algorithms to achieve real-time, QoS-aware, network traffic classification. Three classifiers, namely, Feed-forward Neural Network, Naïve Bayes, and Logistics Regression have been employed with a novel Artificial Neural Network and Particle Swarm Optimization hybridization scheme by carrying first- and second-order stability analysis for performance improvement of these classifiers. In short, the proposed framework exploits optimization algorithms and semi-supervised
machine learning
(
ML
) for precise traffic classification while keeping communication overhead between controller and switches minimal. Results obtained from real-life datasets demonstrate the efficacy of our proposed scheme.
The Minimum Principle of SINR: A Useful Discretization Tool for Wireless Communication
Authors: Kantor Erez , Lotker Zvi , Parter Merav , Peleg David
Published: February 2022

Theoretical study of optimization problems in wireless communication often deals with tasks that concern a single point. For example, the
power control
problem requires computing a power assignment guaranteeing that each transmitting station

s
i

is successfully received at a
single receiver point

r
i

. This paper aims at addressing communication applications that require handling two-dimensional tasks (e.g., guaranteeing successful transmission in entire
regions
rather than at specific points).

The natural approach to two-dimensional optimization tasks is to
discretize
the optimization domain, e.g., by sampling points within the domain. The straightforward implementation of the discretization approach, however, might incur high time and memory requirements, and moreover, it cannot guarantee exact solutions.

The alternative proposed and explored in this paper is based on establishing the
minimum principle

1

for the

signal to interference and noise ratio (SINR)

function with free space path loss (i.e., when the signal decays in proportion to the square of the distance between the transmitter and receiver). Essentially, the minimum principle allows us to reduce the dimension of the optimization domain
without
losing anything in the accuracy or quality of the solution. More specifically, when the two-dimensional optimization domain is bounded and free from any interfering station, the minimum principle implies that it is sufficient to optimize the SINR function over the
boundary
of the domain, as the “hardest” points to be satisfied reside on the boundary and not in the interior.

We then utilize the minimum principle as the basis for an improved discretization technique for solving two-dimensional problems in the SINR model. This approach is shown to be useful for handling optimization problems over two dimensions (e.g., power control, energy minimization); in providing tight bounds on the number of null cells in the reception map; and in approximating geometric and topological properties of the wireless reception map (e.g., maximum inscribed sphere).

The minimum principle, as well as the interplay between continuous and discrete analysis presented in this paper, are expected to pave the way to future study of algorithmic SINR in higher dimensions.
Human-centered approach to static-analysis-driven developer tools
Authors: Nadeem Ayman
Published: February 2022

The future depends on good HCI.
Shared Privacy Concerns of the Visually Impaired and Sighted Bystanders with Camera-Based Assistive Technologies
Authors: Akter Taslima , Ahmed Tousif , Kapadia Apu , Swaminathan Manohar
Published: February 2022

Camera-based assistive technologies can provide people with visual impairments (PVIs) visually derived information about people in their vicinity. Furthermore, the advent of smart glasses offers the possibility of not only analyzing visual information in front of the wearers but also behind them through an extended field of view. Although such ‘visually available’ information can enhance one’s social interactions, the privacy and ethical implications for automated judgments about bystanders, especiallyfrom the perspective of PVIs, remains underexplored. To study the concerns of both bystanders and PVIs with such technologies, we conducted two online surveys with visually impaired participants as wearers (N = 128) and sighted participants as bystanders (N = 136). Although PVIs found some types of information to be improper or impolite (such as someone’s weight), our overarching finding is thesharedethical concern between PVIs and bystanders related to the fallibility of AI, in which bystanders can be misrepresented (algorithmically) by the devices. These mischaracterizations can range from occasional unexpected algorithmic errors (e.g., errors in facial recognition) to the questionable use of AI for determining subjective social constructs (such as gender). Based on our findings, we discuss the design implications and directions for future work in the development of camera-based assistive technologies while mitigating the ethical concerns of PVIs and bystanders.
Picking publication targets
Authors: Baquero Carlos
Published: February 2022

The
Communications
website, http://cacm.acm.org, features more than a dozen bloggers in the BLOG@CACM community. In each issue of
Communications
, we'll publish selected posts or excerpts.

twitter

Follow us on Twitter at http://twitter.com/blogCACM

http://cacm.acm.org/blogs/blog-cacm

Carlos Baquero offers guidance on how to decide where to publish one's paper.
Is a privacy crisis experienced, a privacy crisis avoided?
Authors: Skirpan Michael , Oates Maggie , Byrne Daragh , Cunningham Robert , Cranor Lorrie Faith
Published: February 2022

Exploring immersive theatre as a way to educate audiences and study their perceptions of privacy and technology ethics.
An FPGA-based Approach to Evaluate Thermal and Resource Management Strategies of Many-core Processors
Authors: Mettler Marcel , Rapp Martin , Khdr Heba , Mueller-Gritschneder Daniel , Henkel Jörg , Schlichtmann Ulf
Published: February 2022

The continuous technology scaling of integrated circuits results in increasingly higher power densities and operating temperatures. Hence, modern many-core processors require sophisticated thermal and resource management strategies to mitigate these undesirable side effects. A simulation-based evaluation of these strategies is limited by the accuracy of the underlying processor model and the simulation speed. Therefore, we present, for the first time, an field-programmable gate array (FPGA)-based evaluation approach to test and compare thermal and resource management strategies using the combination of benchmark generation, FPGA-based application-specific integrated circuit (ASIC) emulation, and run-time monitoring. The proposed benchmark generation method enables an evaluation of run-time management strategies for applications with various run-time characteristics. Furthermore, the ASIC emulation platform features a novel distributed temperature emulator design, whose overhead scales linearly with the number of integrated cores, and a novel dynamic voltage frequency scaling emulator design, which precisely models the timing and energy overhead of voltage and frequency transitions. In our evaluations, we demonstrate the proposed approach for a tiled many-core processor with 80 cores on four Virtex-7 FPGAs. Additionally, we present the suitability of the platform to evaluate state-of-the-art run-time management techniques with a case study.
Low-Resistivity Cobalt and Ruthenium Ultra-Thin Film Deposition Using Bipolar HiPIMS Technique
Authors: Seo Min , Cho Min Kyung , Kang Un Hyeon , Jeon Sin Young , Lim Sang-Ho , Han Seung Hee
Published: February 2022

Owing to the rapid growth of very large-scale integration technology at nanometer scales, cobalt and ruthenium interconnects are being used to solve the high-resistivity copper problem. However, with such interconnects, carbon contamination can occur during chemical vapor deposition and atomic layer deposition. Bipolar (BP) high-power impulse magnetron sputtering (HiPIMS) with a high ionization rate is an excellent vacuum process for depositing low-resistivity thin films. In this study, low-resistivity cobalt, ruthenium, and copper thin films were deposited using BP-HiPIMS, HiPIMS, and direct-current magnetron sputtering (DCMS). The resistivities of the cobalt, ruthenium, and copper thin films (<10 nm) deposited via BP-HiPIMS were 91.5, 75, and 35%, respectively, lower than the resistivities of the same film materials deposited using direct-current MS. To solve the low pass-through flux of cobalt, the target temperature was raised to the Curie temperature (approximately 1100 °C) using a thermal insulation backplate (Ti-6Al-4V), resulting in a resistivity reduction of about 73%. The study provides a novel method for the vacuum deposition of cobalt and ruthenium thin films.
Generation Algorithm of a Novel Platform Attached Support Structure for FDM-Fused Deposition Modeling
Authors: Lv Ning , Li Yunxu , Qiao Yujing
Published: February 2022

In the process of 3D printing, the setting of the initial layer is the most important step to achieve perfect printing results, and its main function is to prevent warping in 3D printing. There are three main types of the first layer: Raft, Brim, and Skirt. The Brim is a special skirt and is usually the preferred starting layer for the printing process. In order to increase the adhesion, multiple Brim contour edges will be printed, which increases the difficulty of removal. Otherwise, poor adhesion effect will occur. By analyzing the distinction between inner and outer contours of polygons, the offset process of contour points in different cases is calculated in this paper, and a simplified processing method of contour offset line is designed by using the idea of Douglas–Peucker simplifying curve feature points. According to the functional characteristics of the Brim edge structure, a novel platform attached support structure is generated based on ray-casting algorithm and contour offset algorithm. The proposed algorithm is encapsulated into the slicing engine and compared with three common initial layer structures for conducting part printing comparison experiments. The experimental results show that the edge structure realized by the proposed generation optimization algorithm of a novel platform attached support can effectively reduce the slicing execution time, and the auxiliary structure has little impact on the forming quality. It can be easier to remove on the premise and the warpage of the printing model is small.
Evaluation of the Plant Growth Promotion Effect of Bacillus Species on Different Varieties of Tomato (Solanum lycopersicum L.) Seedlings
Authors: Mengistie Gebeyehu Yibeltie , Awlachew Zewdu Teshome
Published: February 2022

Tomato is the most widely eaten vegetable and used as a good source of vitamins A, B, C, and D and minerals such as calcium, phosphorus, and iron. The study was done to evaluate the effect of Bacillus species isolated from the sediment of Lake Tana on the early growth of different tomato (Solanum lycopersicum L.) varieties. All Bacillus isolates significantly (

P
<
0.05

) increased the growth of all three tomato varieties in terms of shoot length, shoot fresh weight, shoot dry weight, root length, and fresh and dry weights of the root. The isolates’ efficacy varied among tomato varieties. Bacillus isolate B2 was more effective in the Maya variety, with a potency of 85% and 71.2% shoot and root lengths, respectively. Bacillus isolate B3 was more efficient in the Melkesalsa variety, with a shoot and root length efficiency of 57% and 68%, respectively. Bacillus isolate B1 was more successful in the Kochero variety with 65 and 70% shoot and root length efficacy. Individual isolates’ PGPR characteristics differed, resulting in a wide range of effectiveness among different varieties. More research studies are needed to fully know the mechanism of action and efficacy of these isolates in the field. The isolates must also be identified using molecular techniques.
Modeling COVID‐19 Data with a Novel Extended Exponentiated Class of Distributions
Authors: Arif Muhammad , Khan Dost Muhammad , Aamir Muhammad , Khalil Umair , Bantan Rashad A. R. , Elgarhy Mohammed
Published: February 2022

The COVID‐19 epidemic has affected every aspect of daily life since December 2019 and caused massive damage to the world. The coronavirus epidemic has affected more than 150 countries around the world. Many researchers have tried to develop a statistical model which can be utilized to analyze the behavior of the COVID‐19 data. This article contributes to the field of probability theory by introducing a novel family of distributions, named the novel extended exponentiated class of distributions. Explicit expressions for numerous mathematical characterizations of the proposed family have been obtained with special concentration on a three‐parameter submodel of the new class of distributions, named the new extended exponentiated Weibull distribution. The unknown model parameter estimates are obtained via the maximum likelihood estimation method. To assess the performance of these estimates, a comprehensive simulation study is conducted. Three different sets of COVID‐19 data are used to check the applicability of the submodel case. The submodel of the new family is compared with three well‐known probability distributions. Using different analytical measures, the results demonstrate that the new extended exponentiated Weibull distribution gives promising results in terms of its flexibility and offers data modeling with increasing decreasing, unimodal, and modified unimodal shapes.
Effect of Anterior Chamber Instability during Phacoemulsification Combined with Intraocular Lens Implantation
Authors: Geng Wenjing , Lin Wenli , Song Pei , Zhang Min , Wu Jian , Su Shu , Yuan Yurong , Ji Min , Guan Huaijin
Published: February 2022

Purpose. To determine the incidence of anterior chamber (AC) instability during phacoemulsification (phaco) combined with intraocular lens implantation and investigate its effect on intraocular tissues. Methods. Among the 248 enrolled eyes, 121 and 127 eyes were categorized into the irrigation and nonirrigation groups, respectively, depending on the use of a self-made anterior chamber maintainer (ACM) during phaco. AC stability was evaluated using operating microscopy and intraoperative optical coherence tomography (iOCT). Slit-lamp examination of AC flare and cells was performed 1 day postoperatively. Corrected distance visual acuity (CDVA), intraocular pressure (IOP), endothelial cell density (ECD), central corneal thickness (CCT), posterior vitreous detachment (PVD), and central foveal thickness (CFT) were evaluated preoperatively and at 1 week, 1 month, and 3 months postoperatively. Results. There was good consistency in AC stability evaluation between operating microscopy and iOCT. The incidence of AC instability was significantly different between groups after the phaco and irrigation/aspiration tips were withdrawn from the AC

P
<
0.001

. At 1 day postoperatively, after excluding eyes in which the AC could not be visualized, AC cell grades were significantly lower in the irrigation group (P = 0.014). There was no significant difference in CDVA, IOP, ECD, and CCT between groups during the 3-month follow-up

P
>
0.05

. At 1 month and 3 months postoperatively, PVD occurred in 8 (16.3%) and 14 (28.6%) eyes and in 22 (40.7%) and 37 (68.5%) eyes in the irrigation and nonirrigation groups, respectively (P = 0.006 and

P
<
0.001

). CFT was significantly higher in the nonirrigation group at 1 and 3 months postoperatively (P = 0.018 and P = 0.010). Conclusions. Both operating microscopy and iOCT are efficient for AC stability evaluation. When the phaco and I/A tips were withdrawn from the AC, there was frequent instability. Intraoperative AC instability can increase surgery-induced inflammation and lead to postoperative complications such as PVD, retinal detachment, and macular edema. The self-made ACM can effectively reduce the incidence of intraoperative AC instability and these complications.
Valvular Cardiomyopathy: The Value of Cardiovascular Magnetic Resonance Imaging
Authors: Tsampasian Vasiliki , Hothi Sandeep S. , Ravindrarajah Thuwarahan , Swift Andrew J. , Garg Pankaj , Vassiliou Vassilios S.
Published: February 2022

Cardiovascular magnetic resonance (CMR) imaging has had a vast impact on the understanding of a wide range of disease processes and pathophysiological mechanisms. More recently, it has contributed significantly to the diagnosis and risk stratification of patients with valvular heart disease. With its increasing use, CMR allows for a detailed, reproducible, qualitative, and quantitative evaluation of left ventricular volumes and mass, thereby enabling assessment of the haemodynamic impact of a valvular lesion upon the myocardium. Postprocessing of the routinely acquired images with feature tracking CMR methodology can give invaluable information about myocardial deformation and strain parameters that suggest subclinical ventricular impairment that remains undetected by conventional measures such as the ejection fraction (EF). T1 mapping and late gadolinium enhancement (LGE) imaging provide deep myocardial tissue characterisation that is changing the approach towards risk stratification of patients as an increasing body of evidence suggests that the presence of fibrosis is related to adverse events and prognosis. This review summarises the current evidence regarding the utility of CMR in the left ventricular assessment of patients with aortic stenosis or mitral regurgitation and its value in diagnosis, risk stratification, and management.
Intelligent Algorithm Risk and Prevention Mechanism of College Students’ Ideology under the Background of Artificial Intelligence
Authors: Yu Huang You
Published: February 2022

With the rapid development of economic, the artificial intelligence network ideology of mobile Internet of things has become the core part of network security. It is also the most direct embodiment of a national ideology in the network era, and the risk prevention of ideology in colleges and universities is an important part of security work. The values, diversity, and related ideological and moral changes of college students’ ideology are facing complex and severe challenges. In the age of mobile Internet of things, it is especially vital to strengthen and improve the responsibility of ideological values construction of the college students and constantly develop the risk operation and prevention management mechanism of college Internet of things.
Analysis of Exchange Rates as Time-Inhomogeneous Markov Chain with Finite States
Authors: Mettle Felix O. , Boateng Lydia Pomaa , Quaye Enoch N. B. , Aidoo Emmanuel Kojo , Seidu Issah
Published: February 2022

Irrespective of whether the test for homogeneity is significant or not, most researchers assume time-homogeneity in analysing Markov chains due to scanty literature on the analysis of time-inhomogeneous Markov chains. Based on the assumption that, for each point in time in the future, a stochastic process will be subjected to a randomly selected transition matrix from an ergodic set of transition matrices the process was subjected to in the recent past, a methodology was proposed for analysing the long-run behaviours of time-inhomogeneous Markov chains. The proposed model was implemented to historical data consisting of the exchange rate of cedi-dollar, cedi-pound, and cedi-euro spanning over 6 years (January 2012 to December 2017). The results show that under certain “closeness” conditions, the long-run behaviours of the time-inhomogeneous case are almost identical to those of the time-homogeneous case. The paper asserted that even if the Markov chain exhibit time-inhomogeneity, analysing the Markov chain under the assumption of time-homogeneity is a step in the right direction under certain “closeness” conditions; otherwise, the proposed method is recommended. It was also found that investing in dollars yields better returns than the other currencies in Ghana.
Long-Term Evaluation and Normal Tissue Complication Probability (NTCP) Models for Predicting Radiation-Induced Optic Neuropathy after Intensity-Modulated Radiation Therapy (IMRT) for Nasopharyngeal Carcinoma: A Large Retrospective Study in China
Authors: Wu Yan-Ling , Li Wen-Fei , Yang Kai-Bin , Chen Lei , Shi Jing-Rong , Chen Fo-Ping , Huang Xiao-Dan , Lin Li , Zhang Xiao-Min , Li Jing , Chen Yu-Pei , Tang Ling-Long , Mao Yan-Ping , Ma Jun
Published: February 2022

Purpose. To quantify the long-term evaluation of optic chiasma (OC) and/or optic nerve(s) (ONs) and to develop predictive models for radiation-induced optic neuropathy (RION) in nasopharyngeal carcinoma after intensity-modulated radiotherapy (IMRT). Methods and Materials. A total of 3,662 patients’ OC/ONs with full visual acuity and dosimetry data between 2010 and 2015 were identified. Critical dosimetry predictors of RION were chosen by machine learning and penalized regression for survival. A nomogram containing dosimetry and clinical variables was generated for predicting RION-free survival. Results. The median follow-up was 71.79 (2.63–120.9) months. Sixty-six eyes in 51 patients (1.39%) developed RION. Two patients were visual field deficient, and 49 patients had visual acuity of less than 0.1 (20/200). The median latency time was 36 (3–90) months. The 3-, 5-, and 8-year cumulative incidence of RION was 0.78%, 1.19%, and 1.97%, respectively. Dmax was the most critical dosimetry variable for RION (AUC: 0.9434, the optimal cutoff: 64.48 Gy). Patients with a Dmax ≥64.48 Gy had a significantly higher risk of RION (HR = 102.25; 95%CI, 24.86–420.59;

P
<
0.001

). Age (>44 years) (HR = 2.234, 95% CI = 1.233–4.051, p = 0.008), advanced T stage (T3 vs. T1-2: HR = 7.516, 95% CI = 1.725–32.767,

p
=
0.007

; T4 vs. T1-2: HR = 37.189, 95% CI = 8.796–157.266,

P
<
0.001

), and tumor infiltration/compression of the OC/ONs (HR = 4.572, 95% CI = 1.316–15.874,

p
=
0.017

) were significant clinical risk factors of RION. A nomogram comprising age, T stage, tumor infiltration/compression of the OC/ON, and Dmax significantly outperformed the model, with only Dmax predicting RION (C-index: 0.916 vs. 0.880,

P
<
0.001

in the training set; 0.899 vs. 0.874,

P
=
0.038

in the test set). The nomogram-defined high-risk group had a worse 8-year RION-free survival. Conclusions. In the IMRT era, Dmax <60 Gy is safe and represents an acceptable dose constraint for most NPC patients receiving IMRT. A reasonable trade-off for selected patients with unsatisfactory tumor coverage due to proximity to the optic apparatus would be Dmax <65 Gy. Caution should be exercised when treating elderly and advanced T-stage patients or those with tumor infiltration/compression of the OC/ON. Our nomogram shows strong efficacy in predicting RION.
The Value of Diffuse Splenic and Hepatic 18F‐FDG Uptake on PET/CT in Diagnosing Patients with Anemia
Authors: Deng Li , Liu Lin , Ding HaoYuan , Zhang ShuMao , Wang Wei , Zhang Wei , Li Yi
Published: February 2022

Objective. Anemia is a disease with a negative impact on the progression and prognosis of tumor diseases and usually diagnosed by blood tests. Imaging examination has been used as an alternative method to diagnose anemia in addition to blood tests for patients who cannot tolerate blood draw (such as those with severe coagulopathy). The purpose of this study was to investigate the role of diffuse splenic and hepatic 18F‐FDG uptake on PET/CT in anemia, by analyzing the correlation between the hemoglobin level and diffuse splenic and hepatic as well as marrow 18F‐FDG uptakes in patients who underwent PET/CT. Materials and Methods. Forty four patients who underwent a peripheral blood examination within 2 days of a 18F‐FDG‐PET/CT in our hospital from March 2020 to March 2021 were included. The standardized uptake value (SUV) of the spleen, liver, and marrow were measured, including the maximum value (SUVmax) and the mean value (SUVmean), and the CT value (CTV) of the left ventricular (LV) cavity was measured, including the maximum value (CTVmax) and the mean value (CTVmean). The relation between these measurements and the blood hemoglobin level were analyzed. Results. Our analysis revealed that the hemoglobin level was negatively correlated with the SUVmax of the spleen (P ≤ 0.01, R = −0.385), SUVmean of the spleen (P ≤ 0.01, R = −0.395), SUVmax of the liver (P ≤ 0.05, R = −0.365), and SUVmean of the liver (P ≤ 0.05, R = −0.315). The hemoglobin level was positively correlated with CTVmax of the LV cavity (P ≤ 0.05, R = 0.33) and CTVmean of the LV cavity (P ≤ 0.05, R = 0.382), while no statistically significant correlation between the hemoglobin level and the SUV of marrow was observed (P > 0.05). Conclusion. Our study revealed a negative correlation between the hemoglobin level and spleen SUV as well as liver SUV, and a positive correlation between the hemoglobin level and CTV of the LV cavity. These findings may provide potential indictors for the imaging diagnosis of anemia, which has important clinical significance in certain clinical scenarios including the evaluation of anemia status in patients who cannot tolerate blood draws and retrospective clinical studies based on patient imaging data.
A Comparative Biomechanical Analysis of the Impact of Different Configurations of Pedicle-Screw-Based Fixation in Thoracolumbar Compression Fracture
Authors: Szkoda-Poliszuk Klaudia , Załuski Rafał
Published: February 2022

The aim of this experimental study was to analyze the impact of applying different configurations of the transpedicular fixation system on selected mechanical parameters of the thoracolumbar spine under conditions of its instability (after simulated fracture). Five study groups were tested: physiological, with compression fracture of the vertebra, with two-segment fixation, with three-segment fixation, and with four-segment fixation. Each of the analyzed study groups was subjected to axial compression, flexion, and extension. Based on the conducted experimental tests, the mechanical parameters, i.e., stiffness coefficient and dissipation energy, were determined for all groups under consideration. The stiffness value of two-segment fixation is significantly lower than the physiological value (during flexion and extension). The use of long-segment fixation considered in two configurations (three- and four-segment fixation) may result in excessive stiffness of the system due to the high stiffness values achieved (approx. 25–30% higher than the physiological values in the case of compression and on average 60% higher in the case of flexion). The use of long-segment fixator design shows better results than short-segment fixation. Considering both biomechanical and clinical aspects, three-segment fixation seems to be a compromise solution as it saves the patient from more extensive stiffening of the spinal motion segments.