bluuebunny/crossref_metadata_2025 huggingface dataset:
No findings of SARS-CoV-2 in conjunctival swabs from patients at an emergency outpatient ophthalmological healthcare facility in a Swedish county hospital: a cross-sectional study
Authors: Granstam Elisabet , Krifors Anders , Freyhult Elisabeth , Åkerblom Hanna
Published: March 2021

Background

COVID-19 is caused by SARS-CoV-2. Virus has been found in conjunctiva of hospitalised patients with COVID-19. Conjunctivitis has also been reported as a presenting symptom of disease.

Objective

The aims of the study were to investigate the prevalence of SARS-CoV-2 in the conjunctiva and throat among patients presenting at the emergency outpatient ophthalmological healthcare facility at a county hospital along with investigating the seroprevalence of SARS-CoV-2 among staff at the department.

Methods and Analysis

Swabs from conjunctiva and throat of patients were analysed with real-time reverse transcriptase PCR (RT-PCR) for SARS-CoV-2. Blood samples for serological analysis were obtained from staff. A questionnaire was used to investigate symptoms associated with COVID-19 during the last 3 months as well as symptoms for which the patients were seeking ophthalmological healthcare.

Results

In total, 68 patients and 70 individuals from the staff were included in the study. Conjunctivitis was observed in 7% of patients. One patient, presenting with reduced visual acuity due to preretinal haemorrhage in the macula, was positive for SARS-CoV-2 in throat swab. Contact tracing was negative. All other RT-PCR tests were negative. Seropositivity for SARS-CoV-2 was found in 4% of staff.

Conclusions

Our study demonstrated low prevalence of SARS-CoV-2 among patients as well as low seroprevalence of SARS-CoV-2 IgG-antibodies among staff at the ophthalmological ward. The risk for contracting COVID-19 at the department was small. Follow-up investigation is planned.
Improving the accuracy of ICD-10 coding of morbidity/mortality data through the introduction of an electronic diagnostic terminology tool at the general hospitals in Lagos, Nigeria
Authors: Olagundoye Olawunmi , van Boven Kees , Daramola Olufunmilola , Njoku Kendra , Omosun Adenike
Published: March 2021

Background

Reliable information which can only be derived from accurate data is crucial to the success of the health system. Since encoded data on diagnoses and procedures are put to a broad range of uses, the accuracy of coding is imperative. Accuracy of coding with the International Classification of Diseases, 10th revision (ICD-10) is impeded by a manual coding process that is dependent on the medical records officers’ level of experience/knowledge of medical terminologies.

Aim statement

To improve the accuracy of ICD-10 coding of morbidity/mortality data at the general hospitals in Lagos State from 78.7% to ≥95% between March 2018 and September 2018.

Methods

A quality improvement (QI) design using the Plan–Do–Study–Act cycle framework. The interventions comprised the introduction of an electronic diagnostic terminology software and training of 52 clinical coders from the 26 general hospitals. An end-of-training coding exercise compared the coding accuracy between the old method and the intervention. The outcome was continuously monitored and evaluated in a phased approach.

Results

Research conducted in the study setting yielded a baseline coding accuracy of 78.7%. The use of the difficult items (wrongly coded items) from the research for the end-of-training coding exercise accounted for a lower coding accuracy when compared with baseline. The difference in coding accuracy between manual coders (47.8%) and browser-assisted coders (54.9%) from the coding exercise was statistically significant. Overall average percentage coding accuracy at the hospitals over the 12-month monitoring and evaluation period was 91.3%.

Conclusion

This QI initiative introduced a stop-gap for improving data coding accuracy in the absence of automated coding and electronic health record. It provides evidence that the electronic diagnostic terminology tool does improve coding accuracy and with continuous use/practice should improve reliability and coding efficiency in resource-constrained settings.
Typical within and between person variability in non-invasive ventilator derived variables among clinically stable, long-term users
Authors: Jeganathan Vishnu , Rautela Linda , Conti Simon , Saravanan Krisha , Rigoni Alyssa , Graco Marnie , Hannan Liam M , Howard Mark E , Berlowitz David J
Published: March 2021

Background

Despite increasing capacity to remotely monitor non-invasive ventilation (NIV), how remote data varies from day to day and person to person is poorly described.

Methods

Single-centre, 2-month, prospective study of clinically stable adults on long-term NIV which aimed to document NIV-device variability. Participants were switched to a ventilator with tele-monitoring capabilities. Ventilation settings and masking were not altered. Raw, extensible markup language data files were provided directly from Philips Respironics (EncoreAnywhere). A nested analysis of variance was conducted on each ventilator variable to apportion the relative variation between and within participants.

Results

Twenty-nine people were recruited (four withdrew, one had insufficient data for analyses; 1364 days of data). Mean age was 54.0 years (SD 18.4), 58.3% male with body mass index of 37.0 kg/m2(13.7). Mean adherence was 8.53 (2.23) hours/day and all participants had adherence >4 hours/day. Variance in ventilator-derived indices was predominantly driven by differences between participants; usage (61% between vs 39% within), Apnoea–Hypopnoea Index (71% vs 29%), unintentional (64% vs 36%) and total leak (83% vs 17%), tidal volume (93% vs 7%), minute ventilation (92% vs 8%), respiratory rate (92% vs 8%) and percentage of triggered breaths (93% vs 7%).

Interpretation

In this clinically stable cohort, all device-derived indices were more varied between users than the day-to-day variation within individuals. We speculate that normative ranges and thresholds for clinical intervention need to be individualised, and further research is necessary to determine the clinically important relationships between clinician targets for therapy and patient-reported outcomes.
Validation of the STOP-Bang questionnaire as a screening tool for obstructive sleep apnoea in patients with cardiovascular risk factors: a systematic review and meta-analysis
Authors: Hwang Mark , Zhang Kevin , Nagappa Mahesh , Saripella Aparna , Englesakis Marina , Chung Frances
Published: March 2021

Introduction

Obstructive sleep apnoea (OSA) is highly prevalent in patients with cardiovascular risk factors and is associated with increased morbidity and mortality. This review presents the predictive parameters of the STOP-Bang questionnaire as a screening tool for OSA in this population.

Methods

A search of databases was performed. The inclusion criteria were: (1) use of the STOP-Bang questionnaire to screen for OSA in adults (>18 years) with cardiovascular risk factors; (2) polysomnography or home sleep apnoea testing performed as a reference standard; (3) OSA defined by either Apnoea–Hypopnoea Index (AHI) or Respiratory Disturbance Index; and (4) data on predictive parameters of the STOP-Bang questionnaire. A random-effects model was used to obtain pooled predictive parameters of the STOP-Bang questionnaire.

Results

The literature search resulted in 3888 articles, of which 9 papers met the inclusion criteria, involving 1894 patients. The average age of the included patients was 58±13 years with body mass index (BMI) of 30±6 kg/m2, and 64% were male. The STOP-Bang questionnaire has a sensitivity of 89.1%, 90.7% and 93.9% to screen for all (AHI ≥5), moderate-to-severe (AHI ≥15) and severe (AHI≥30) OSA, respectively. The specificity was 32.3%, 22.5% and 18.3% and the area under the curve (AUC) was 0.86, 0.65 and 0.52 for all, moderate-to-severe and severe OSA, respectively.

Conclusion

The STOP-Bang questionnaire is an effective tool to screen for OSA (AHI≥5) with AUC of 0.86 in patients with cardiovascular risk factors.
Inspiratory crackles—early and late—revisited: identifying COPD by crackle characteristics
Authors: Melbye Hasse , Aviles Solis Juan Carlos , Jácome Cristina , Pasterkamp Hans
Published: March 2021

Background

The significance of pulmonary crackles, by their timing during inspiration, was described by Nath and Capel in 1974, with early crackles associated with bronchial obstruction and late crackles with restrictive defects. Crackles are also described as ‘fine’ or ‘coarse’. We aimed to evaluate the usefulness of crackle characteristics in the diagnosis of chronic obstructive pulmonary disease (COPD).

Methods

In a population-based study, lung sounds were recorded at six auscultation sites and classified in participants aged 40 years or older. Inspiratory crackles were classified as ‘early’ or ‘late and into the types’ ‘coarse’ and ‘fine’ by two observers. A diagnosis of COPD was based on respiratory symptoms and forced expiratory volume in 1 s/forced inspiratory vital capacity below lower limit of normal, based on Global Lung Function Initiative 2012 reference. Associations between crackle characteristics and COPD were analysed by logistic regression. Kappa statistics was applied for evaluating interobserver agreement.

Results

Of 3684 subjects included in the analysis, 52.9% were female, 50.1% were ≥65 years and 204 (5.5%) had COPD. Basal inspiratory crackles were heard in 306 participants by observer 1 and in 323 by observer 2. When heard bilaterally COPD could be predicted with ORs of 2.59 (95% CI 1.36 to 4.91) and 3.20 (95% CI 1.71 to 5.98), annotated by observer 1 and 2, respectively, adjusted for sex and age. If bilateral crackles were coarse the corresponding ORs were 2.65 (95% CI 1.28 to 5.49) and 3.67 (95% CI 1.58 to 8.52) and when heard early during inspiration the ORs were 6.88 (95% CI 2.59 to 18.29) and 7.63 (95%CI 3.73 to 15.62). The positive predictive value for COPD was 23% when early crackles were heard over one or both lungs. We observed higher kappa values when classifying timing than type.

Conclusions

‘Early’ inspiratory crackles predicted COPD more strongly than ‘coarse’ inspiratory crackles. Identification of early crackles at the lung bases should imply a strong attention to the possibility of COPD.
Endovascular repair for abdominal aortic aneurysms
Authors: Debono Samuel , Nash Jennifer , Tambyraja Andrew L , Newby David E , Forsythe Rachael O
Published: March 2021

Management of abdominal aortic aneurysms has been the subject of rigorous scientific scrutiny. Prevalence studies have directed the formation of screening programmes, and observational studies and randomised controlled trials have defined aneurysm growth and treatment thresholds. Pre-emptive intervention with traditional open surgical repair has been the bedrock of improving long-term outcome and survival in patients with abdominal aortic aneurysms but it is associated with a significant procedural morbidity and mortality. Endovascular aneurysm repair (EVAR) has substantially reduced these early complications and has been associated with promising results in both elective and emergency aneurysm repair. However, the technique has brought its own unique complications, endoleaks. An endoleak is the presence of blood flow within the aneurysm sac but outside the EVAR graft. Although in randomised control trials EVAR was associated with a reduced early mortality compared with open repair, its longer-term morbidity and mortality was higher because endoleak development is associated with a higher risk of rupture. These endoleak complications have necessitated the development of postoperative imaging surveillance and re-intervention. These contrasting benefits and risks inform the selection of the mode of repair and are heavily influenced by individual patient factors. An improved strategy to predict endoleak development could further help direct treatment choice for patients and improve both early and late outcomes. This article reviews current EVAR practice, recent updates in clinical practice guidelines and the potential future developments to facilitate the selection of mode of aneurysm repair.

Trial registration number: ClinicalTrials.gov NCT04577716.
Interrupted time series analysis to evaluate the performance of drug overdose morbidity indicators shows discontinuities across the ICD-9-CM to ICD-10-CM transition
Authors: Yang Hannah , Pasalic Emilia , Rock Peter , Davis James W , Nechuta Sarah , Zhang Ying
Published: March 2021

Introduction

On 1 October 2015, the USA transitioned from the International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) to the International Classification of Diseases, 10th Revision (ICD-10-CM). Considering the major changes to drug overdose coding, we examined how using different approaches to define all-drug overdose and opioid overdose morbidity indicators in ICD-9-CM impacts longitudinal analyses that span the transition, using emergency department (ED) and hospitalisation data from six states’ hospital discharge data systems.

Methods

We calculated monthly all-drug and opioid overdose ED visit rates and hospitalisation rates (per 100 000 population) by state, starting in January 2010. We applied three ICD-9-CM indicator definitions that included identical all-drug or opioid-related codes but restricted the number of fields searched to varying degrees. Under ICD-10-CM, all fields were searched for relevant codes. Adjusting for seasonality and autocorrelation, we used interrupted time series models with level and slope change parameters in October 2015 to compare trend continuity when employing different ICD-9-CM definitions.

Results

Most states observed consistent or increased capture of all-drug and opioid overdose cases in ICD-10-CM coded hospital discharge data compared with ICD-9-CM. More inclusive ICD-9-CM indicator definitions reduced the magnitude of significant level changes, but the effect of the transition was not eliminated.

Discussion

The coding change appears to have introduced systematic differences in measurement of drug overdoses before and after 1 October 2015. When using hospital discharge data for drug overdose surveillance, researchers and decision makers should be aware that trends spanning the transition may not reflect actual changes in drug overdose rates.
Active management of the target P2Y12 reaction unit range in patients undergoing stent-assisted coil embolization for unruptured cerebral aneurysms
Authors: Nakagawa Ichiro , Park Hun Soo , Kotsugi Masashi , Yokoyama Shohei , Nakase Kenta , Furuta Takanori , Myouchin Kaoru , Yamada Shuichi , Nakase Hiroyuki
Published: March 2021

Background

Platelet function tests have been increasingly adopted to measure patient responses to antiplatelet drugs, and to predict complications. However, no established optimal antiplatelet management for stent-assisted coil embolization (SAC) have been established. The purpose of the present study was to investigate the efficacy and feasibility of clopidogrel dose adjustment for active target P2Y12 reaction unit (PRU).

Methods

A total of 202 consecutive patients undergoing SAC to treat unruptured intracranial aneurysms were prospectively recruited. All patients were given two antiplatelet agents starting 7 days prior to the procedure, and platelet function was measured with the VerifyNow test. Clopidogrel hyper-responsive patients received reduced dosing according to the values of follow-up PRUs before and 7, 14, 30, and 90 days after the procedure. Patients were divided into three groups according to clopidogrel responsiveness before treatment, and clinical outcomes and time in target PRU ranges (TTR) were analyzed.

Results

No delayed ischemic or hemorrhagic events occurred that were associated with out-of-range PRU. PRU values in the hypo-responsive and hyper-responsive groups significantly improved 7 days after treatment with active target PRU management (p=0.05,<0.001, respectively). PRU values were controlled within the target PRU range with drug adjustment (p=0.034), and the time in TTR for all patients was 97% (4.8%–100%), which showed the feasibility of optimal control of PRU values with the protocol.

Conclusion

Active target PRU management can achieve control of optimal PRU values and may decrease perioperative ischemic and hemorrhagic events among patients undergoing SAC.
The unbiased diffusion Monte Carlo: a versatile tool for two-electron systems confined in different geometries
Authors: Micca Longo Gaia , Coppola Carla Maria , Giordano Domenico , Longo Savino
Published: March 2021

Computational codes based on the diffusion Monte Carlo method can be used to determine the quantum state of two-electron systems confined by external potentials of various natures and geometries. In this work, we show how the application of this technique in its simplest form, that does not employ complex analytic guess functions, allows to obtain satisfactory results and, at the same time, to write programs that are readily adaptable from one type of confinement to another. This adaptability allows an easy exploration of the many possibilities in terms of both geometry and structure of the system. To illustrate these results, we present calculations in the case of two-electron hydrogen-based species ($$\hbox {H}_{2}$$

H
2

and $$\hbox {H}_{3}^{+})$$

H

3

+

)

and two different types of confinement, nanotube-like and octahedral crystal field.

Graphic abstract
[Retracted] Inhibition Effect of Zoledronate on the Osteoclast Differentiation of RAW264.7 Induced by Titanium Particles
Authors: Zhao Wenhan , Huang Zhusong , Lin Yu , Lan Jinfu , Gao Xi
Published: March 2021

Objective. This study is aimed at studying the effect of zoledronate (ZOL) on the differentiation of osteoclast precursor RAW264.7 cells induced by titanium (Ti) particles and explores the possibility of preventing and treating periprosthetic osteoporosis using ZOL. Methods. RAW264.7 cells were cultured in vitro. Ti particles were prepared. The cell proliferation curve of RAW264.7 cells was plotted using the MTT assay to find the best concentration of ZOL for intervention. The cells were divided into three groups: control, Ti particles, and Ti particles+ZOL. The cell morphology was observed using tartaric acid–resistant acid phosphatase (TRAP) staining, and the activity of TRAP in cell supernatant was determined using the biochemical method. The number of bone resorption lacunae was detected using toluidine blue staining. The mRNA expression of RANK, NFATcl, CAII, and MMP-9 was detected using real‐time polymerase chain reaction. The protein expression of RANK, NFATcl, and MMP‐9 was detected using Western blot analysis. Results. Ti particles stimulated the differentiation of RAW264.7 cells into osteoclasts. They also increased the activity of TRAP, number of bone resorption lacunae, and mRNA and protein expression of RANK, NFATcl, and MMP‐9. However, ZOL could suppress the effect of TI particles on the osteoclast differentiation of RAW264.7 cells. Conclusions. ZOL could effectively inhibit the differentiation of RAW264.7 cells into osteoclasts induced by Ti particles, decrease the activity of TRAP, reduce the number of bone resorption lacunae, and decrease the mRNA and protein expression of RANK, NFATcl, and MMP‐9. Hence, it may be a promising candidate for preventing and treating periprosthetic osteoporosis after the artificial joint operation.
Padé-Sumudu-Adomian Decomposition Method for Nonlinear Schrödinger Equation
Authors: Richard Metomou , Zhao Weidong
Published: March 2021

The main purpose of this paper is to solve the nonlinear Schrödinger equation using some suitable analytical and numerical methods such as Sumudu transform, Adomian Decomposition Method (ADM), and Padé approximation technique. In many literatures, we can see the Sumudu Adomian decomposition method (SADM) and the Laplace Adomian decomposition method (LADM); the SADM and LADM provide similar results. The SADM and LADM methods have been applied to solve nonlinear PDE, but the solution has small convergence radius for some PDE. We perform the SADM solution by using the function

P

L
/
M

·

called double Padé approximation. We will provide the graphical numerical simulations in 3D surface solutions of each application and the absolute error to illustrate the efficiency of the method. In our methods, the nonlinear terms are computed using Adomian polynomials, and the Padé approximation will be used to control the convergence of the series solutions. The suggested technique is successfully applied to nonlinear Schrödinger equations and proved to be highly accurate compared to the Sumudu Adomian decomposition method.
The Prevalence of Headache and Associated Factors in Al-Kharj, Saudi Arabia: A Cross-Sectional Study
Authors: Almalki Daifallah , Shubair Mamdouh M. , Al-Khateeb Badr F , Obaid Alshammari Rawan Abdullah , Alshahrani Saeed Mastour , Aldahash Raed , Angawi Khadijah , Alsalamah Majid , Al-Zahrani Jamaan , Al-Ghamdi Sameer , Al-Zahrani Hayat Saleh , El-Metwally Ashraf , Aldossari Khaled K.
Published: March 2021

Background. Only few studies have investigated the prevalence and risk factors of headaches among the Saudi population. The study aimed to estimate the prevalence of headache and to explore its associated risk factors Al-Kharj, Saudi Arabia. Methods. The multistage sampling technique was used to enroll 1200 population-based participants who were asked to complete a self-administered questionnaire about headaches, demographics, and several other parameters such as smoking status and different chronic and psychological illnesses. The chi-square test and multivariate logistic regression analysis were used to test the association. Results. The overall prevalence of headaches in this study was 3%. The multiple logistic regression analysis showed that females were more likely to have headaches than males (odds ratio (OR) 0.735, 95% confidence interval (CI) = 0.612–1.341;

P
=
0.024

). Being a current smoker was also significantly associated with higher “odds” of having headache (OR = 1.319, 95% CI = 0.932–2.462;

P
=
0.037

). Participants who were overweight had a significantly higher risk of headache (OR = 1.631, 95% CI = 1.48–1.854;

P
=
0.037

). Nonmarried people were significantly more likely to have headache pain, compared to married individuals (OR = 0.875, 95% CI = 0.646–2.317;

P
=
0.047

). Conclusion. The prevalence of headaches was 3%, and four significant associated factors were identified: females, nonmarried, smoking, and overweight. The temporality of the relationship between these factors and headache cannot be confirmed in this cross-sectional study; so future longitudinal studies are needed to confirm these potential causal relationships.
An Efficient Recommendation Algorithm Based on Heterogeneous Information Network
Authors: Yin Ying , Zheng Wanning
Published: March 2021

Heterogeneous information networks can naturally simulate complex objects, and they can enrich recommendation systems according to the connections between different types of objects. At present, a large number of recommendation algorithms based on heterogeneous information networks have been proposed. However, the existing algorithms cannot extract and combine the structural features in heterogeneous information networks. Therefore, this paper proposes an efficient recommendation algorithm based on heterogeneous information network, which uses the characteristics of graph convolution neural network to automatically learn node information to extract heterogeneous information and avoid errors caused by the manual search for metapaths. Furthermore, by fully considering the scoring relationship between nodes, a calculation strategy combining heterogeneous information and a scoring information fusion strategy is proposed to solve the scoring between nodes, which makes the prediction scoring more accurate. Finally, by updating the nodes, the training scale is reduced, and the calculation efficiency is improved. The study conducted a large number of experiments on three real data sets with millions of edges. The results of the experiments show that compared with PMF, SemRec, and other algorithms, the proposed algorithm improves the recommendation accuracy MAE by approximately 3% and the RMSE by approximately 8% and reduces the time consumption significantly.
Rare Organism Uncommon Disease Case Vignette of Guillain–Barré Syndrome Induced by Fusobacterium nucleatum Infection
Authors: Shah K. , Ahmed A. , Kaveh K. , Frugoli A. , Hammoudi M.
Published: March 2021

In this case report, we describe an unusual pathogen F. nucleatum-induced empyema, followed by the development of Guillain–Barré syndrome (GBS). Although many pathogens have been associated with GBS, this may be one of the few in the literature to describe an association with F. nucleatum infection.
Cervical Cancer Screening—Past, Present, and Future
Authors: Wentzensen Nicolas , Clarke Megan A.
Published: March 2021

Cervical cancer screening has undergone a transformation in recent decades. Historically, programs were based on cervical cytology (i.e., “Pap smear”), which had to be repeated often because of its limited sensitivity and reproducibility. In more recent years, the discovery of human papillomavirus (HPV) as the necessary cause of virtually all cervical cancers has led to the introduction of HPV testing into clinical practice, first as a triage test for minor cytologic abnormalities, then in conjunction with cervical cytology (cotesting), and most recently, as a standalone screening test. Multiple randomized trials have shown that HPV-based screening has higher sensitivity compared with cytology, providing great reassurance against cervical precancer and cancer for women testing HPV-negative for many years. Analyses have also been conducted in support of the recent U.S. Preventive Services Task Force guidelines that show that primary HPV screening achieves the greatest balance of benefits and harms compared with other strategies. An added benefit of primary HPV testing is the ability to conduct it from self-collected samples, which is critical for extending coverage among hard-to-reach individuals and could provide a safe and effective alternative to in-person screening visits during the COVID-19 pandemic.

See related article by Liang et al., p. 474
A fast and robust reference current generation algorithm for three-phase shunt active power filter
Authors: Chedjara Zakaria , Massoum Ahmed , Wira Patrice , Safa Ahmed , Gouichiche Abdelmadjid
Published: March 2021

The identification of the reference currents constitutes an important part of the control of the active power filter. This part requires an accurate estimation of the frequency, phase, and proper extraction of the load current harmonics. This makes the modeling more difficult and requests a rigorous selection of techniques to be used. For the sake of simplicity, the direct method is motivated by the need for the simplicity and flexibility than the existing techniques such as the instantaneous power theory and diphase currents method. However, this method requires a robust phase-locked loop to extract the unity voltages and a robust controller to estimate the magnitude of the source current. To this end, this paper proposes the hybrid phase-locked loop (HPLL) as a good option mainly because 1) it achieves zero phase error under frequency drifts, 2) Fast dynamic response, 3) totally block the DC offset, 4) From the control point of view, it is a type 1 control system which results in high stability margin. To the best of authors’ knowledge, the HPLL has not been used in active power filter yet. Furthermore, a neural PI regulator is used to estimate the magnitude of the source current. Simulation results show the efficiency of the proposed technique and illustrate all its interesting features. For the sake of comparison, the proposed method is compared to other advanced techniques.
Simulation model of single phase PWM inverter by using MATLAB/Simulink
Authors: Shneen Salam Waley , Abdullah Fatin Nabeel , Shaker Dina Harith
Published: March 2021

This work is presenting under the title simulation model of single phase PWM inverter by using MATLAB/Simulink. There are many researchers’ works in this field with the different ways because it is important field and it has many applications. The converter DC power to AC power for any system that mean it need the power electronic device (inverter). The inverter is using when the source DC power and the load AC power. In this work, the simulation system includes the source 300V DC power, inverter, LC filter and load (R). The simulation result shows the waveform of all part in this system like input and output current and voltage.
Grid to vehicle wireless power supply using single-phase matrix converter
Authors: Akram Muhamad Haziq Mohmad , Baharom Rahimi
Published: March 2021

This paper presents the computer simulation model of a grid to vehicle (G2V) wireless power supply using a single-phase matrix converter (SPMC). The proposed system uses the SPMC that operates as a direct AC-AC converter to convert the supply frequency of 50 Hz to reach 20 kHz output frequency. The use of 20 kHz frequency is suitable for wireless power transfer (WPT) operation in order to obtain higher power transfer efficiency between the transmitter and the receiver parts. An advanced of the proposed circuit topology can solve the conventional system for G2V circuit topology that uses multiple stages of power conversion system, resulting in high power semiconductor losses that could lead to low efficiency. In this work, multiple stages of the conventional "AC-DC-AC" circuits have been reduced to a single power conversion stage by using the SPMC circuit topology. The use of the proposed circuit topology can reduce the number of devices, thus reduce the semiconductor losses. A part of reducing the semiconductor losses, the proposed circuit topology could also improve the power density and efficiency of the power supply system. A computer simulation model using MATLAB/Simulink has been developed to investigate the behavior of the proposed system. Selected simulation results are presented to verify the functionality of the proposed system.
Mitigating the dead-time effects on harmonics spectrum of inverter waveform by the confined band VSFPWM technique
Authors: Attia Hussain , Che Hang Seng , Freddy Tan Kheng Suan , Elkhateb Ahmad
Published: March 2021

The dead-time is necessary to be inserted between the gates drive pulses of the two power electronic switches in a one leg of any inverter to avoid a short circuit in the leg and the DC supply as well. However, adding the dead-time increases the low order harmonics of the output voltage/current waveform of the inverter. This paper investigates the positive effects of decreasing the pulse width modulation (PWM) drive pulses number per fundamental period on the current low order harmonics. In addition, this paper evaluates the impact of the confined band variable switching frequency pulse width modulation (CB-VSFPWM) technique on inverter performance in terms of dead-time mitigating, and consequenctely lowering the low order harmonics. CB-VSFPWM technique reduces the total harmonic distortion (THD) levels in the inverter output current as well. Theoretical analysis of the CB-VSFPWM effectiveness in reducing the negative effect of the dead-time has explained in this study and confirmed by the MATLAB/Simulink simulation results.
Fuzzy logic control of active and reactive power for a grid-connected photovoltaic system using a three-level neutral-point-clamped inverter
Authors: Tahri Ghrissi , Foitih Zoubir Ahmed , Tahri Ali
Published: March 2021

This paper aims to present a fuzzy logic control (FLC) of active and reactive power for a grid-connected photovoltaic system. The PV system is connected to the grid utility using a three-level neutral point clamped inverter (3L-NPC) and LCL filter. Two control strategies, fuzzy logic control, and conventional PI control are applied. The design of the two control strategies is based on calculating the instantaneous active and reactive power from the measured grid voltages and currents to allow the system to have a dynamic robustness performance against a sudden change in reactive power and satisfactory active power tracking under rapid solar radiation changes. The control strategies can transfer the total active power generated by the PV array to the grid utility with high power quality and a unity power factor. The simulation results using the Matlab-Simulink environment show that the FLC strategy has a better dynamic performance with less settling time, and overshoot compared to the conventional PI control.
Faults diagnosis in stator windings of high speed solid rotor induction motors using fuzzy neural network
Authors: Radhi Ahmed Thamer , Zayer Wael Hussein
Published: March 2021

The paper deals with faults diagnosis method proposed to detect the inter-turn and turn to earth short circuit in stator winding of three-phase high-speed solid rotor induction motors. This method based on negative sequence current of motor and fuzzy neural network algorithm. On the basis of analysis of 2-D electromagnet field in the solid rotor the rotor impedance has been derived to develop the solid rotor induction motor equivalent circuit. The motor equivalent circuit is simulated by MATLAB software to study and record the data for training and testing the proposed diagnosis method. The numerical results of proposed approach are evaluated using simulation of a three-phase high-speed solid-rotor induction motor of two-pole, 140 Hz. The results of simulation shows that the proposed diagnosis method is fast and efficient for detecting inter-turn and turn to earth faults in stator winding of high-speed solid-rotor induction motors with different faults conditions
Experimental study of the VFD’s speed stabilization efficiency under torque disturbances
Authors: Kodkin Vladimir L. , Anikin Aleksandr S.
Published: March 2021

The article presents a technique for experimental research of variable frequency drives experiencing periodic torque disturbances of variable frequency. The technique is based on the nonlinear transfer function of a link of an asynchronous electric motor, which forms an electromagnetic torque, proposed in previously published articles. The dependence of the transfer function on the frequency of the stator voltage and slip determines the research methodology. Experiments have shown the advantage of the dynamic characteristics of a drive with a positive feedback on the stator current over electric drives with traditional control methods (vector and scalar sensorless), and in terms of dynamic characteristics they also exceed drives with a vector control closed in motor speed. These advantages are retained when the frequency of change of the disturbing torque is changed from 0 to 5 Hz.
Effect of Empagliflozin as an Add-On Therapy on Decongestion and Renal Function in Patients With Diabetes Hospitalized for Acute Decompensated Heart Failure
Authors: Tamaki Shunsuke , Yamada Takahisa , Watanabe Tetsuya , Morita Takashi , Furukawa Yoshio , Kawasaki Masato , Kikuchi Atsushi , Kawai Tsutomu , Seo Masahiro , Abe Makoto , Nakamura Jun , Yamamoto Kyoko , Kayama Kiyomi , Kawahira Masatsugu , Tanabe Kazuya , Fujikawa Kei , Hata Masahisa , Fujita Yohei , Umayahara Yutaka , Taniuchi Satsuki , Sanada Shoji , Shintani Ayumi , Fukunami Masatake
Published: March 2021

Background:

Empagliflozin reduces the risk of hospitalization for heart failure in patients with type 2 diabetes and cardiovascular disease. We sought to elucidate the effect of empagliflozin as an add-on therapy on decongestion and renal function in patients with type 2 diabetes admitted for acute decompensated heart failure.

Methods:

The study was terminated early due to COVID-19 pandemic. We enrolled 59 consecutive patients with type 2 diabetes admitted for acute decompensated heart failure. Patients were randomly assigned to receive either empagliflozin add-on (n=30) or conventional glucose-lowering therapy (n=29). We performed laboratory tests at baseline and 1, 2, 3, and 7 days after randomization. Percent change in plasma volume between admission and subsequent time points was calculated using the Strauss formula.

Results:

There were no significant baseline differences in left ventricular ejection fraction and serum NT-proBNP (N-terminal pro-B-type natriuretic peptide), hematocrit, or serum creatinine levels between the 2 groups. Seven days after randomization, NT-proBNP level was significantly lower in the empagliflozin group than in the conventional group (
P
=0.040), and hemoconcentration (≥3% absolute increase in hematocrit) was more frequently observed in the empagliflozin group than in the conventional group (
P
=0.020). The decrease in percent change in plasma volume between baseline and subsequent time points was significantly larger in the empagliflozin group than in the conventional group 7 days after randomization (
P
=0.017). The incidence of worsening renal function (an increase in serum creatinine ≥0.3 mg/dL) did not significantly differ between the 2 groups.

Conclusions:

In this exploratory analysis, empagliflozin achieved effective decongestion without an increased risk of worsening renal function as an add-on therapy in patients with type 2 diabetes with acute decompensated heart failure.

Registration:

URL:
https://www.umin.ac.jp/ctr/index.htm
; Unique identifier: UMIN000026315.
Supervised and Unsupervised Neural Approaches to Text Readability
Authors: Martinc Matej , Pollak Senja , Robnik-Šikonja Marko
Published: March 2021

We present a set of novel neural supervised and unsupervised approaches for determining the readability of documents. In the unsupervised setting, we leverage neural language models, whereas in the supervised setting, three different neural classification architectures are tested. We show that the proposed neural unsupervised approach is robust, transferable across languages, and allows adaptation to a specific readability task and data set. By systematic comparison of several neural architectures on a number of benchmark and new labeled readability data sets in two languages, this study also offers a comprehensive analysis of different neural approaches to readability classification. We expose their strengths and weaknesses, compare their performance to current state-of-the-art classification approaches to readability, which in most cases still rely on extensive feature engineering, and propose possibilities for improvements.
Yinming Logic and Dialogue in the Contact Zone
Authors: Assandri Friederike
Published: March 2021

This article presents a case of the application of Buddhist yinming logic in a public debate between Buddhists and Daoists at the court of Emperor Tang Gaozong, as recorded by Daoxuan in his Ji Gujin Fo Dao Lunheng. The application was successful in the sense that the Buddhist vanquished his Daoist opponent. Yet, yinming logic was not used in other debates against Daoists, not even by Buddhists trained in this particular logic. Why? Looking for answers to this question, the article argues for the importance of common analytical ground in inter-religious, and by extension intercultural debate.
Controversy Over “Jullien,” or Where and What is China, Philosophically Speaking?
Authors: Weber Ralph
Published: March 2021

This article is about François Jullien and a controversy that arose over the publication of a pamphlet by Jean Franc¸ois Billeter entitled Against François Jullien, replied by Jullien in a volume subtitled Reply to *** (the asterisks standing for Billeter) and followed by collections of essays by French (and some German) intellectuals—one of them entitled For Jullien. The controversy assumed a weight that went beyond Jullien and the French debate to the heart of sinology and also of philosophy. The question, what and where China is philosophically speaking, is discussed with regard to the role of context, the notion of heterotopy, and the political side of talk about China.
Summer Extreme Cyclone Impacts on Arctic Sea Ice
Authors: Lukovich Jennifer V. , Stroeve Julienne C. , Crawford Alex , Hamilton Lawrence , Tsamados Michel , Heorton Harry , Massonnet François
Published: March 2021

In this study the impact of extreme cyclones on Arctic sea ice in summer is investigated. Examined in particular are relative thermodynamic and dynamic contributions to sea ice volume budgets in the vicinity of Arctic summer cyclones in 2012 and 2016. Results from this investigation illustrate that sea ice loss in the vicinity of the cyclone trajectories during each year was associated with different dominant processes: thermodynamic processes (melting) in the Pacific sector of the Arctic in 2012, and both thermodynamic and dynamic processes in the Pacific sector of the Arctic in 2016. Comparison of both years further suggests that the Arctic minimum sea ice extent is influenced by not only the strength of the cyclone, but also by the timing and location relative to the sea ice edge. Located near the sea ice edge in early August in 2012, and over the central Arctic later in August in 2016, extreme cyclones contributed to comparable sea ice area (SIA) loss, yet enhanced sea ice volume loss in 2012 relative to 2016. Central to a characterization of extreme cyclone impacts on Arctic sea ice from the perspective of thermodynamic and dynamic processes, we present an index describing relative thermodynamic and dynamic contributions to sea ice volume changes. This index helps to quantify and improve our understanding of initial sea ice state and dynamical responses to cyclones in a rapidly warming Arctic, with implications for seasonal ice forecasting, marine navigation, coastal community infrastructure, and designation of protected and ecologically sensitive marine zones.
Effects of Wave–Current Interactions on Bay–Shelf Exchange
Authors: Song Dehai , Wu Wen , Li Qiang
Published: March 2021

Bay–shelf exchange is critical to coastal systems because it promotes self-purification or pollution dilution of the systems. In this study, the effects of wave–current interactions on bay–shelf exchange are explored in a micromesotidal system—Daya Bay in southern China. Waves can enlarge the shear-induced seaward transport and reduce the residual-current-induced landward transport, which benefits the bay–shelf exchange; however, tides work oppositely and slow the wave-induced bay–shelf exchange through vertical mixing and reduced shear-induced exchange. Five wave–current interactions are compared, and it is found that the depth-dependent wave radiation stress (WRS) contributes most to the bay–shelf exchange, followed by the wave dissipation as a source term in the turbulence kinetic energy equation, and the mean current advection and refraction of wave energy (CARWE). The vertical transfer of wave-generated pressure to the mean momentum equation (also known as the form drag) and the combined wave–current bottom stress (CWCBS) play minor roles in the bay–shelf exchange. The bay–shelf exchange is faster under southerly wind than under northerly wind because the bay is facing southeast; synoptic events such as storms enhance the bay–shelf exchange. The CARWE terms are dominant in both seasonal and synoptic variations of the bay–shelf exchange because they can considerably change the distribution of significant wave height. The WRS changes the bay–shelf exchange mainly through altering the flow velocity, whereas the wave dissipation on turbulence alters the vertical mixing. The form drag and the CWCBS have little impact on the bay–shelf exchange or its seasonal and synoptic variations.
Lymph or Chyle Leak After Neck Dissection in Patients With Thyroid Carcinoma: Results of a Study on 1724 Patients
Authors: Wang Xi , Wang Shunlan , Li Chunqiao , Ruan Yan , Li Yin , Liu Jing , Guo Zhuming
Published: March 2021

Background

To discuss the prevention and treatment of lymph or chyle leak following neck dissection in patients with thyroid carcinoma.

Methods

A total of 1724 patients with thyroid carcinoma received neck dissection in the Sun Yat-sen University Cancer Center between November 2009 and October 2014. The incidence and management of leak were analyzed.

Results

A total of 92 (5.34%) patients developed leak, 28 (1.62%) developed lymph leak, 59 (3.42%) developed chyle leak, and 5 (.29%) developed chylothorax. Medical management to stop postoperative lymph or chyle leak included pressure dressing, reoperation, fasting, or low-fat diet therapy.

Conclusions

Lymph or chyle leak may occur in thyroid carcinoma patients who underwent neck dissection. Clinicians should alert to leak when there were IV + VI region lymph node metastasis and should become aware of chylothorax after pressure dressing. A careful identification and ligation of lymphatic duct may be an effective way to avoid lymph or chyle leak.
Abdominal Aortic Intima-Media Thickness Predicts Coronary Artery Disease Severity in Patients With Stable Angina Pectoris: A Prospective Study
Authors: Cirakoglu Omer Faruk , Karadeniz Ayşe Gül , Akyüz Ali Riza , Aydın Cihan , Şahin Sinan , Erkan Hakan
Published: March 2021

Accurately identifying coronary artery disease (CAD) is the key element in guiding the work-up of patients with suspected angina. Thickening of the arterial wall is a hallmark of atherosclerosis. Therefore, the main purpose of this study was to determine whether abdominal aortic intima-media thickness (AAIMT), which is the earliest zone of atherosclerotic manifestations, has a predictive value in CAD severity. A total of 255 consecutive patients who were referred for invasive coronary angiography due to suspected stable angina pectoris were prospectively included in the study. B-mode ultrasonography was used to determine AAIMT before coronary angiography. Coronary artery disease severity was assessed with the SYNTAX score (SS). A history of hypertension, age, dyslipidemia, and higher AAIMT (odds ratio: 2.570; 95%CI 1.831-3.608; P < .001) were independent predictors of intermediate or high SS. An AAIMT <1.3 mm had a negative predictive value of 98% for the presence of intermediate or high SS and 83% for obstructive CAD. In conclusion, AAIMT showed a significant and independent predictive value for intermediate or high SS. Therefore, AAIMT may be a noninvasive and useful tool for decision-making by cardiologists (eg, to use a more invasive approach).
Impact of the Injectable Opioid Drug Shortage on Analgesia and Sedation Management in the Medical Intensive Care Unit: A Retrospective Cohort Study
Authors: John Kayla , Cape Kari , Goodman Lauren , Elefritz Jessica
Published: March 2021

Objectives: The purpose of this study was to assess the impact of the injectable opioid drug shortage on analgesia and sedation management in the medical intensive care unit (MICU). Methods: A single-center, retrospective cohort study was conducted of mechanically ventilated patients during the injectable opioid shortage. Outcomes were compared between a cohort of patients during the intravenous (IV) opioid shortage (01/01/18-03/31/18) and a control cohort (01/01/17-03/31/17). Total IV opioids and alternative sedative administration were assessed. Richmond Agitation Sedation Score (RASS) and Clinical Pain Observation Score (CPOT) assessments were also evaluated. The primary outcome was percentage of RASS within goal. Secondary outcomes included duration of mechanical ventilation, hospital/ICU length of stay, and mortality. Results: One hundred patients were included (50 patients per cohort). In the shortage cohort, 23.2% fewer IV opioids were used (40 501.8 vs 52 713.8 oral morphine equivalents [OME]). No statistical differences were found in percentage of patients within goal RASS between the shortage and control (median 63.7% vs 74.8%; P = .094) or CPOT (median 49.7% vs 47.7%; P = .575). More patients received enteral opioids and propofol on day 1 in the shortage cohort when compared to the control (22% vs 4%; P = .007 and 76% vs 56%; P = .035) but there were no differences in benzodiazepine, dexmedetomidine, or antipsychotic use. No differences in mechanical ventilation, hospital/ICU length of stay, or mortality were found. Conclusions: Use of less IV opioids during the injectable opioid shortage did not affect achievement of goal RASS and CPOT scores or increase prescribing of sedative medications such as benzodiazepines in the MICU.