bluuebunny/crossref_metadata_2025 huggingface dataset:
Synonymous Codon Pair Recoding of the HIV-1 env Gene Affects Virus Replication Capacity
Authors: Jordan-Paiz Ana , Franco Sandra , Martinez Miguel Angel
Published: June 2021

Synonymous codon pair deoptimization is an efficient strategy for virus attenuation; however, the underlying mechanism remains controversial. Here, we optimized and deoptimized the codon pair bias (CPB) of the human immunodeficiency virus type 1 (HIV-1) envelope (env) gene to investigate the influence of env synonymous CPB recoding on virus replication capacity, as well as the potential mechanism. We found that env CPB deoptimization did not always generate attenuation, whereas CPB optimization attenuated virus replication in MT-4 cells. Furthermore, virus attenuation correlated with reduced Env protein production but not with decreased viral RNA synthesis. Remarkably, in our model, increasing the number of CpG dinucleotides in the 5′ end of env did not reduce the replication capacity of HIV-1. These results indicate that factors other than CPB or CpG content may have impacted the viral fitness of the synonymously recoded study variants. Our findings provide evidence that CPB recoding-associated attenuation can affect translation efficiency. Moreover, we demonstrated that an increased number of CpGs in the 5′ end of HIV-1 env is not always associated with reduced virus replication capacity.
Parental Engagement of a Prototype Electronic Diary in an Ambulatory Setting Following Adenotonsillectomy in Children: A Prospective Cohort Study
Authors: Mchugh Tobial , Brown Karen A. , Daniel Sam J. , Balram Sharmila , Frigon Chantal
Published: June 2021

Adenotonsillectomy is performed in children on an outpatient basis, and pain is managed by parents. A pain diary would facilitate pain management in the ambulatory setting. Our objective was to evaluate the parental response rate and the compliance of a prototype electronic pain diary (e-diary) with cloud storage in children aged 2–12 years recovering from adenotonsillectomy and to compare the e-diary with a paper diary (p-diary). Parents recorded pain scores twice daily in a pain diary for 2 weeks post-operation. Parents were given the choice of an e-diary or p-diary with picture message. A total of 208 patients were recruited, of which 35 parents (16.8%) chose the e-diary. Most parents (98%) chose to be contacted by text message. Eighty-one families (47%) returned p-diaries to us by mail. However, the response rate increased to 77% and was similar to that of the e-diary (80%) when we included data texted to the research phone from 53 families. The proportion of diaries with Complete (e-diary:0.37 vs. p-diary:0.4) and Incomplete (e-diary:0.43 vs. p-diary:0.38) data entries were similar. E-diaries provide a means to follow patients in real time after discharge. Our findings suggest that a smartphone-based medical health application coupled with a cloud would meet the needs of families and health care providers alike.
Reading Skills of Children with Dyslexia Improved Less Than Expected during the COVID-19 Lockdown in Italy
Authors: Baschenis Ilaria Maria Carlotta , Farinotti Laura , Zavani Elena , Grumi Serena , Bernasconi Patrizia , Rosso Enrica , Provenzi Livio , Borgatti Renato , Termine Cristiano , Chiappedi Matteo
Published: June 2021

Following school closures due to the SARS-CoV-2 pandemic, for some months, children received only distance learning. The effects of this approach, however, are not clear for children with dyslexia. We conducted a cross-sectional comparison between children with and without dyslexia after the so-called “lockdown” and a comparison between pre- and post-lockdown parameters in children with dyslexia. We recruited sixty-five children with dyslexia (dyslexia group, DG) from an outpatient facility in Pavia (Lombardy, Italy) and fifty-two children without specific learning disabilities as the control group (CG) from summer camps in the same province. We performed neuropsychological tests to explore reading skills and an ad hoc questionnaire to explore how parents and children had experienced the measures taken to reduce spreading of SARS-CoV-2 infection. Between 59 to 63% of children with dyslexia did not reach the average expected increase of reading skills. According to their parents, they also showed greater social isolation and fewer worries about the pandemic and the school’s closure. Our data indicate that children with dyslexia are at increased risk of consequences on their learning potential in case of school closure. They also seem to have a peculiar psychological experience of school closure. Specific interventions should therefore be provided to minimize the risk of negative effects on global development.
Clinical Evaluation of a Novel Urine Collection Kit Using Filter Paper in Neonates: An Observational Study
Authors: Nagano Nobuhiko , Imaizumi Takayuki , Akimoto Takuya , Hijikata Midori , Aoki Ryoji , Seimiya Ayako , Okahashi Aya , Kawakami Kaori , Komatsu Atsushi , Kawana Kei , Morioka Ichiro
Published: June 2021

Urine bags are commonly used to collect urine samples from neonates. However, the sample can be contaminated by stool, or detachment of the bag due to body movement can lead to failure of the collection. A qualitative urine collection kit containing ten filter papers of 3.2 mm diameter was developed and clinically verified among 138 neonates. During a single diaper change (approximately 3 h), the rate of urine collection was calculated. Urine collection was considered to be successful if any filter paper in the urine collection sheet turned from blue to white. Of the 127 neonates who passed urine, 122 had a change in the filter paper. The urine collection rate was 96%, with changes in all 10 filter papers observed in 98 neonates (80%). Urine collection rate was not influenced by sex (p = 1.00), age at collection (p = 0.72), preterm birth (p = 1.00), low birth weight (p = 0.92), or fecal contamination (p = 1.00). The incidence of dermatitis was not higher than in the group in which urine bags were used (urine collection kit: 2/68 [3%]; urine bag: 5/68 [7%]; p = 0.44). Novel urine collection kits using filter paper can collect samples from neonates safely and with a high probability of success.
Assessing Impact of Climate Variability in Southwest Coastal Bangladesh Using Livelihood Vulnerability Index
Authors: Mehzabin Sabrina , Mondal M. Shahjahan
Published: June 2021

This study analyzed the variability of rainfall and temperature in southwest coastal Bangladesh and assessed the impact of such variability on local livelihood in the last two decades. The variability analysis involved the use of coefficient of variation (CV), standardized precipitation anomaly (Z), and precipitation concentration index (PCI). Linear regression analysis was conducted to assess the trends, and a Mann–Kendall test was performed to detect the significance of the trends. The impact of climate variability was assessed by using a livelihood vulnerability index (LVI), which consisted of six livelihood components with several sub-components under each component. Primary data to construct the LVIs were collected through a semi-structed questionnaire survey of 132 households in a coastal polder. The survey data were triangulated and supplemented with qualitative data from focused group discussions and key informant interviews. The results showed significant rises in temperature in southwest coastal Bangladesh. Though there were no discernable trends in annual and seasonal rainfalls, the anomalies increased in the dry season. The annual PCI and Z were found to capture the climate variability better than the currently used mean monthly standard deviation. The comparison of the LVIs of the present decade with the past indicated that the livelihood vulnerability, particularly in the water component, had increased in the coastal polder due to the increases in natural hazards and climate variability. The index-based vulnerability analysis conducted in this study can be adapted for livelihood vulnerability assessment in deltaic coastal areas of Asia and Africa.
Effect of Low-Energy Nitrogen Ion Implantation on Friction and Wear Properties of Ion-Plated TiC Coating
Authors: Dou Zhongyu , Guo Yinglu , Zhang Faguang , Zhang Dianxi
Published: June 2021

To further improve the performance of the coated tools, we investigated the effects of low-energy nitrogen ion implantation on surface structure and wear resistance for TiC coatings deposited by ion plating. In this experiment, an implantation energy of 40 keV and a dose of 2 × 1017 to 1 × 1018 (ions/cm2) were used to implant N ions into the TiC coatings. The results indicate that the surface roughness of the coating increases first and then decreases with the increase of ion implantation dose. After ion implantation, the surface of the coating will soften and reduce the hardness, and the production of TiN phase will gradually increase the hardness. Nitrogen ion implantation can reduce the friction coefficient of the TiC coating and improve the friction performance. In terms of wear resistance, the coating with an implant dose of 1×1018 ions/cm2 has the greatest improvement in wear resistance. Tribological analysis shows that the improvement in the performance of TiC coatings implanted with N ions is mainly due to the effect of the lubricating implanted layer. The implanted layer mainly exists in the form of amorphous TiC, TiN phase, and sp2C–C phase.
Bone Density around Titanium Dental Implants Coating Tested/Coated with Chitosan or Melatonin: An Evaluation via Microtomography in Jaws of Beagle Dogs
Authors: López-Valverde Nansi , López-Valverde Antonio , Aragoneses Juan Manuel , Martínez-Martínez Francisco , González-Escudero María C. , Ramírez Juan Manuel
Published: June 2021

Peri-implant bone density plays an important role in the osseointegration of dental implants. The aim of the study was to evaluate via micro-CT, in Hounsfield units, the bone density around dental implants coated with chitosan and melatonin and to compare it with the bone density around implants with a conventional etched surface after 12 weeks of immediate post-extraction placement in the jaws of Beagle dogs. Six dogs were used, and 48 implants were randomly placed: three groups—melatonin, chitosan, and control. Seven 10 mm × 10 mm regions of interest were defined in each implant (2 in the crestal zone, 4 in the medial zone, and 1 in the apical zone). A total of 336 sites were studied with the AMIDE tool, using the Norton and Gamble classification to assess bone density. The effect on bone density of surface coating variables (chitosan, melatonin, and control) at the crestal, medial, and apical sites and the implant positions (P2, P3, P4, and M1) was analyzed at bivariate and multivariate levels (linear regression). Adjusted effects on bone density did not indicate statistical significance for surface coatings (p = 0.653) but did for different levels of ROIs (p < 0.001) and for positions of the implants (p = 0.032). Micro-CT, with appropriate software, proved to be a powerful tool for measuring osseointegration.
Analysis of the Anti-Skid Properties of New Airfield Pavements in Aspect of Applicable Requirements
Authors: Zieja Mariusz , Wesołowski Mariusz , Blacha Krzysztof , Iwanowski Paweł
Published: June 2021

The assessment of the anti-skid properties of airfield pavements is one of the elements in the process of determining their current technical condition, which is important in terms of the safety of air operations. The condition of the pavement should be qualified on the basis of the specified and required values (criteria), in this case, the coefficient of friction and the depth of the texture. Unfortunately, in practice, the assessment of the texture of new airfield pavements raises some doubts with regard to the existing requirements. The work presents an analysis of the results of texture tests for new airfield pavements in relation to current requirements. In addition, the authors proposed a new criterion of average texture depth for new airfield pavements, based on actual field measurement results. Field studies used an innovative method of assessing anti-skid properties with a measuring system that allows simultaneous measurement of the coefficient of friction, μ, and the new continuous coefficient of average profile depth and texture CMPTD, from which MPD (Mean Profile Depth) and ETD (Estimated Texture Depth) can be determined. The results of the tests cast doubt on the possibility of obtaining the average texture depth (currently 1.00 mm) required for new airfield pavements.
Pulsed Reverse Potential Electrodeposition of Carbon-Free Ni/NiO Nanocomposite Thin Film Electrode for Energy Storage Supercapacitor Electrodes
Authors: Nuamah Rania Afia , Noormohammed Saleema , Sarkar Dilip Kumar
Published: June 2021

A combined cyclic voltammetry and pulse reverse potential electrodeposition technique has been used to synthesize carbon-free Ni/NiO nanocomposite thin film supercapacitor electrode. The structural and morphological analyses have revealed the presence of crystalline phases of both Ni and NiO in the form of nanospheres of size ~50 nm. The electrochemical analysis of the Ni/NiOna nocomposite electrode has shown a remarkable performance by delivering a high specific capacitance of 2000 Fg−1 at an applied current load of 1 Ag−1 and a capacitance retention of 98.6%, after over 800 cycles under a high current load of 20 Ag−1.
Laser-Assisted Floating Zone Growth of BaFe2S3 Large-Sized Ferromagnetic-Impurity-Free Single Crystals
Authors: Amigó Maria Lourdes , Maljuk Andrey , Manna Kaustuv , Stahl Quirin , Felser Claudia , Hess Christian , Wolter Anja U.B. , Geck Jochen , Seiro Silvia , Büchner Bernd
Published: June 2021

The quasi-one-dimensional antiferromagnetic insulator BaFe2S3 becomes superconducting under a hydrostatic pressure of ∼10 GPa. Single crystals of this compound are usually obtained by melting and further slow cooling of BaS or Ba, Fe, and S, and are small and needle-shaped (few mm long and 50–200 μm wide). A notable sample dependence on the antiferromagnetic transition temperature, transport behavior, and presence of superconductivity has been reported. In this work, we introduce a novel approach for the growth of high-quality single crystals of BaFe2S3 based on a laser-assisted floating zone method that yields large samples free of ferromagnetic impurities. We present the characterization of these crystals and the comparison with samples obtained using the procedure reported in the literature.
A Current and Newly Proposed Artificial Intelligence Algorithm for Reading Small Bowel Capsule Endoscopy
Authors: Oh Dong Jun , Hwang Youngbae , Lim Yun Jeong
Published: June 2021

Small bowel capsule endoscopy (SBCE) is one of the most useful methods for diagnosing small bowel mucosal lesions. However, it takes a long time to interpret the capsule images. To solve this problem, artificial intelligence (AI) algorithms for SBCE readings are being actively studied. In this article, we analyzed several studies that applied AI algorithms to SBCE readings, such as automatic lesion detection, automatic classification of bowel cleanliness, and automatic compartmentalization of small bowels. In addition to automatic lesion detection using AI algorithms, a new direction of AI algorithms related to shorter reading times and improved lesion detection accuracy should be considered. Therefore, it is necessary to develop an integrated AI algorithm composed of algorithms with various functions in order to be used in clinical practice.
Acute Zonal Occult Outer Retinopathy (AZOOR) Results from a Clinicopathological Mechanism Different from Choriocapillaritis Diseases: A Multimodal Imaging Analysis
Authors: Herbort Carl P. , Arapi Ilir , Papasavvas Ioannis , Mantovani Alessandro , Jeannin Bruno
Published: June 2021

Background and aim: AZOOR is a rare disease characterized by loss of zones of outer retinal function, first described by J Donald Gass in 1993. Symptoms include acute onset photopsias and subjective visual field losses. The syndrome is characterized by a normal fundus appearance, scotomas and electroretinographic changes pointing towards outer retinal dysfunction. Evolution, response to immunosuppressive treatment and outcome are difficult to predict. The aim of this small case series was to identify the morphological changes and sequence of events in AZOOR thanks to multimodal imaging. Methods: Charts of AZOOR patients seen in the Centre for Ophthalmic Specialized care (COS, Lausanne, Switzerland) were analyzed by multimodal imaging including fundus photography, fluorescein angiography (FA), indocyanine green angiography (ICGA), blue light fundus autofluorescence (BL-FAF) and spectral domain optical coherence tomography (SD-OCT) in addition to a complete ophthalmological examination including visual field testing and microperimetry, as well as OCT angiography (OCT-A) and ganglion-cell complex analysis when available. Cases and Results: Three AZOOR patients with a mean follow-up of 47 ± 25.5 months were included following the clinical definitions laid down by J Donald Gass. The primary damage was identified at the level of the photoreceptor outer segments with an intact choriocapillaris and retinal pigment epithelium (RPE) layer, these structures being only secondarily involved with progression of the disease. Conclusion: Although AZOOR has often been included within white dot syndromes, some of which are now known to be choriocapillaris diseases (choriocapillaritis entities), our findings clearly commend to differentiate AZOOR from entities such as MEWDS (Multiple evanescent white dot syndrome), APMPPE (Acute Posterior Multifocal Placoid Pigment Epitheliopathy), MFC (Multifocal Choroiditis) and others, as the damage to photoreceptors is primary in AZOOR (a retinopathy) and secondary in choriocapillaritis (a choriocapillaropathy).
Can Fetal Echocardiographic Measurements of the Left Ventricular Outflow Tract Angle Detect Fetuses with Conotruncal Cardiac Anomalies?
Authors: Raucher Sternfeld Alona , Betzer Tal , Tamir Akiva , Mizrachi Yossi , Assa Sagie , Bar Jacob , Gindes Liat
Published: June 2021

Objectives: The angle between the inter-ventricular septum and the ascending aorta can be measured during a sonographic fetal survey while viewing the left ventricular outflow tract (LVOT angle). Our aim was to compare the LVOT angle between fetuses with and without conotruncal cardiac anomaliesrmations. Methods: In this prospective observational study, we compared the LVOT angle between normal fetuses, at different gestational age, and fetuses with cardiac malformations. Results: The study included 302 fetuses screened at gestational age of 12–39 weeks. The LVOT angle ranged from 127 to 163 degrees (mean 148.2), in 293 fetuses with normal hearts, and was not correlated with gestational age. The LVOT angle was significantly wider in fetuses with D-transposition of the great arteries (D-TGA, eight fetuses) and valvar aortic stenosis (AS, three fetuses), than in fetuses with normal hearts (164.8 ± 5.0 vs. 148.2 ± 5.4, respectively, p < 0.001). Conversely, the LVOT angle was significantly narrower in fetuses with complete atrioventricular canal defect (AVC, eight fetuses), than in fetuses with normal hearts (124.8 ± 2.4 vs. 148.2 ± 5.4, respectively, p < 0.001). On ROC analysis, an angle of 159.6 degrees or higher had a sensitivity of 100% and a specificity of 97.3% for the detection of TGA or AS, whereas an angle of 128.8 degrees or lower had a sensitivity of 100% and a specificity of 99.7% for the detection of AVC defect. Conclusions: The LVOT angle is constant during pregnancy, and differs significantly in fetuses with TGA/AS, and AVC, compared to fetuses with normal hearts (wider and narrower, respectively).
The Importance of Accessible Information in Promoting the Inclusion of People with an Intellectual Disability
Authors: Terras Melody M. , Jarrett Dominic , McGregor Sharon A.
Published: June 2021

People with an intellectual disability experience high levels of social exclusion and a range of health inequalities. Increased inclusion and participation in healthcare decision making have been identified as key to promoting inclusion in health and social care. However, achieving these objectives requires increased recognition of the communication and health literacy needs of individuals with an intellectual disability and consideration of the appropriateness of the information currently provided. In this article, we report the results of a pre-COVID-19 qualitative study exploring the provision and use of accessible information to support the healthcare inclusion of individuals with an intellectual disability. A total of 35 clinicians participated in focus group discussions, and 10 people with intellectual disabilities and 10 carers were interviewed regarding their experiences of using accessible health-related information. Qualitative data analysis using a framework approach highlighted the crucial role of communication partners when using accessible information, deficits in current National Health Service (NHS: UK’s publicly funded health care system) information provision in the UK, and possible broader relevance of accessible resources. The implications of these findings for the provision of accessible information in a post-COVID-19 environment are explored, and recommendations are made for the increased integration and theory-driven research to inform the provision, content, and use of health-related information, especially the provision of online information, in the future.
Clinical Outcomes in Burns Patients with Early Venous Thromboembolism Prophylaxis Compared with Late-Anticoagulated Patients: A Retrospective Study
Authors: Brazilek Rose , Cleland Heather J.
Published: June 2021

The aim of this study was to describe the timing of venous thromboembolism diagnosis in patients with severe burns and determine the relationship between venous thromboembolism prophylaxis and venous thromboembolism development in a large trauma hospital. A retrospective cohort study over 10 years from 2009 to 2019 was conducted. Records of 226 patients with >20% total body surface area burns were surveyed, and 20 patients with symptoms suggestive of venous thromboembolism had a diagnosis of VTE confirmed on imaging. Enoxaparin was the most common primary thromboprophylaxis (85%, n = 192), followed by heparin (13.71%, n = 31) and sequential compression devices (0.88%, n = 2). Compared with patients who did not develop a venous thromboembolism, patients who developed a venous thromboembolism had a mean difference in time from admission to thromboprophylaxis prescription of 1.72 days (95% CI = −1.50 to 4.92, p > 0.05) and 10.51 days in those who developed a pulmonary embolus (mean difference = 10.51, 95% CI = 3.73 to 17.32, p = 0.0006). A threshold of 4 days was identified by which 96% of patients who never developed venous thromboembolism during admission were prescribed prophylaxis, compared with 32% of those who developed a pulmonary embolus. No bleeding or adverse events were recorded. Timely prescription of thromboprophylaxis in patients with severe burns is critical in reducing venous thromboembolism incidence. Avoidance of delay post injury is especially critical in preventing venous thromboembolism development. Guidelines on thromboprophylaxis must be considered on an individualised patient basis, considering likely surgical requirements and obesity.
The Response of Housing Construction to a Copper Price Shock in Chile (2009–2020)
Authors: Idrovo-Aguirre Byron J. , Contreras-Reyes Javier E.
Published: June 2021

The copper price is a leading indicator of real estate activity. Price increases are statistically related to increasing numbers of applications for residential building permits. However, this reciprocity is not instantaneous as permit numbers lag price rises by 9 to 10 months. This dynamic is implicit in various transmission channels: from the first effects on investment plans and demand for durable goods due to better expectations from investors and consumers to the real impact of higher copper revenues on the economy’s aggregate production and demand (multiplier or second-round effect). In this paper, we proposed the impulse-response functions of a vector autoregressive model to capture the dynamic between the copper price and house building permits. Therefore, it would be expected that the recent copper price increase will boost construction and real estate activity. The effects could materialize this year and extend into early 2022.
Design of a Laboratory Scale Solar Microgrid Cyber-Physical System for Education
Authors: Guo Liping , Kors Jason
Published: June 2021

Renewable energy sources such as solar and wind provide an effective solution for reducing dependency on conventional power generation and increasing the reliability and quality of power systems. Presented in this paper are design and implementation of a laboratory scale solar microgrid cyber-physical system (CPS) with wireless data monitoring as a teaching tool in the engineering technology curriculum. In the system, the solar panel, battery, charge controller, and loads form the physical layer, while the sensors, communication networks, supervisory control and data acquisition systems (SCADA) and control systems form the cyber layer. The physical layer was seamlessly integrated with the cyber layer consisting of control and communication. The objective was to create a robust CPS platform and to use the system to promote interest in and knowledge of renewable energy among university students. Experimental results showed that the maximum power point tracking (MPPT) charge controller provided the loads with power from the solar panel and used additional power to charge the rechargeable battery. Through the system, students learned and mastered key concepts and knowledge of multi-disciplinary areas including data sampling and acquisition, analog to digital conversion, solar power, battery charging, control, embedded systems and software programing. It is a valuable teaching resource for students to study renewable energy in CPS.
Hardware-in-the-Loop and Digital Control Techniques Applied to Single-Phase PFC Converters
Authors: Lamo Paula , de Castro Angel , Sanchez Alberto , Ruiz Gustavo A. , Azcondo Francisco J. , Pigazo Alberto
Published: June 2021

Power electronic converters for power factor correction (PFC) play a key role in single-phase electrical power systems, ensuring that the line current waveform complies with the applicable standards and grid codes while regulating the DC voltage. Its verification implies significant complexity and cost, since it requires long simulations to verify its behavior, for around hundreds of milliseconds. The development and test of the controller include nominal, abnormal and fault conditions in which the equipment could be damaged. Hardware-in-the-loop (HIL) is a cost-effective technique that allows the power converter to be replaced by a real-time simulation model, avoiding building prototypes in the early stages for the development and validation of the controller. However, the performance-vs-cost trade-off associated with HIL techniques depends on the mathematical models used for replicating the power converter, the load and the electrical grid, as well as the hardware platform chosen to build it, e.g., microprocessor or FPGA, and the required number of channels and I/O types to test the system. This work reviews state-of-the-art HIL techniques and digital control techniques for single-phase PFC converters.
Head Detection Based on DR Feature Extraction Network and Mixed Dilated Convolution Module
Authors: Liu Junwen , Zhang Yongjun , Xie Jianbin , Wei Yan , Wang Zewei , Niu Mengjia
Published: June 2021

Pedestrian detection for complex scenes suffers from pedestrian occlusion issues, such as occlusions between pedestrians. As well-known, compared with the variability of the human body, the shape of a human head and their shoulders changes minimally and has high stability. Therefore, head detection is an important research area in the field of pedestrian detection. The translational invariance of neural network enables us to design a deep convolutional neural network, which means that, even if the appearance and location of the target changes, it can still be recognized effectively. However, the problems of scale invariance and high miss detection rates for small targets still exist. In this paper, a feature extraction network DR-Net based on Darknet-53 is proposed to improve the information transmission rate between convolutional layers and to extract more semantic information. In addition, the MDC (mixed dilated convolution) with different sampling rates of dilated convolution is embedded to improve the detection rate of small targets. We evaluated our method on three publicly available datasets and achieved excellent results. The AP (Average Precision) value on the Brainwash dataset, HollywoodHeads dataset, and SCUT-HEAD dataset reached 92.1%, 84.8%, and 90% respectively.
Assessment in Software Development for Competitive Environments: An AI Strategy Development Case Study
Authors: Palomo-Duarte Manuel , García-Domínguez Antonio , Balderas Antonio
Published: June 2021

Competitions are being widely used to motivate students in diverse learning processes, including those in computer programming. This paper presents a methodology for designing and assessing competitive learning scenarios that allow students to develop three different coding skills: the ability to compete against unknown competitors, the ability to compete against known competitors and the ability to compete against refined versions of known competitors. The proposal is based on peer code review, implemented as an improvement cycle after the dissemination of the code among participants. A case study evaluating the methodology was conducted with two cohorts of students in an undergraduate course. The analysis of the obtained grades suggests that while performance after our assistance was improved, students could still fail or succeed independently of the assistance. Complementary data from student questionnaires and supervisor observations are aligned with this finding. As a conclusion, the evidence supports the validity of the methodology. Additionally, several guidelines based on the experience are provided to transfer the proposal to other environments.
Orbital Angular Momentum-Based Multiple-Input-Multiple- Output with Receive Antenna Shift Keying for 6G
Authors: Lee Sang-Hoon , Al Amin Ahmed , Shin Soo-Young
Published: June 2021

Spectral efficiency is a major concern for future 6G wireless communication systems. Thus, an appropriate scheme is needed to provide channel capacity improvement for multiple transmitters and receiver-based wireless communication systems without consuming extra resource for communication (e.g., frequency/time/code) or causing interference. Therefore, to fulfill the mentioned requirements for the future 6G wireless network, orbital angular momentum-based multiple-input-multiple-output (OAM-MIMO) multiplexing technique is incorporated with the receive antenna shift keying (RASK) technique in this study (termed as the OAM-MIMO-RASK scheme). OAM-MIMO-RASK can transfer multiple symbols from multiple transmitters to different receivers simultaneously by using multiple subchannels using the OAM and RASK techniques without any interference or additional resource (frequency/time/code). The numerical results illustrated that the proposed OAM-MIMO-RASK can achieve almost double capacity than the existing OAM-MIMO scheme and significantly higher capacity than the existing RASK-based scheme for different values of signal-to-noise ratio. Moreover, the simulation result is validated by the theoretical result which is also shown by the numerical result. In addition, due to different normalized distances from the transmitters and receivers, the proposed OAM-MIMO-RASK scheme can achieve almost double capacity than the existing OAM-MIMO scheme by using OAM-MIMO and RASK technique effectively which is also depicted by the numerical results.
Pinhole Formation in Printed Electronic Traces Fabricated via Molten Metal Droplet Jetting
Authors: Meda Manoj , Sukhotskiy Viktor , Cormier Denis
Published: June 2021

The fabrication of printed electronic devices via molten metal droplet jetting has enormous potential in flexible electronic device applications due to the extremely high electrical conductivity and excellent substrate adhesion of printed features. However, large pinholes (which could be detrimental to the feature performance) have been experimentally observed when molten metal droplets of aluminum 4043 alloy are deposited and solidified on a polyimide (PI) substrate. In this study, we have shown that subjecting the polymer substrate to elevated temperature during droplet deposition considerably reduces the number and size of pinholes. The formation mechanism behind the large pinholes is interpreted as the release of the adsorbed/absorbed moisture from the polymer substrate into the solidifying droplet due to the rapid rise in temperature of the substrate upon droplet impact. Through numerical modelling, we have shown that the temperature of the polyimide substrate underneath the deposited droplet exceeds the boiling point of water while the metal droplet is still in liquid state, showing the possibility of water vapor escaping from the substrate and causing pinholes in the solidifying metal.
Comparison of Reactive Power Control Techniques for Solar PV Inverters to Mitigate Voltage Rise in Low-Voltage Grids
Authors: Almeida Dilini , Pasupuleti Jagadeesh , Ekanayake Janaka
Published: June 2021

The greater integration of solar photovoltaic (PV) systems into low-voltage (LV) distribution networks has posed new challenges for the operation of power systems. The violation of voltage limits attributed to reverse power flow has been recognized as one of the significant consequences of high PV penetration. Thus, the reactive power control of PV inverters has emerged as a viable solution for localized voltage regulation. This paper presents a detailed study on a typical Malaysian LV distribution network to demonstrate the effectiveness of different reactive power control techniques in mitigating overvoltage issues due to high PV integration. The performance of four reactive power control techniques namely, fixed power factor control, scheduled power factor control, power factor control as a function of injected active power, and voltage-dependent reactive power control were analyzed and compared in terms of the number of customers with voltage violations, reactive power compensation, and network losses. Three-phase, time-series, high-resolution power-flow simulations were performed to investigate the potential overvoltage issues and to assess the performance of the adoption of reactive power controls in the network. The simulation results revealed that the incorporation of reactive power controls of solar PV inverters aids in successfully mitigating the overvoltage issues of typical Malaysian networks. In particular, the Volt-Var control outperformed the other control techniques by providing effective voltage regulation while requiring less reactive power compensation. Furthermore, the comparative analysis highlighted the significance of employing the most appropriate control technique for improved network performance.
Small-Signal Model and Stability Control for Grid-Connected PV Inverter to a Weak Grid
Authors: Musengimana Antoine , Li Haoyu , Zheng Xuemei , Yu Yanxue
Published: June 2021

This paper presents a small signal stability analysis to assess the stability issues facing PV (photovoltaic) inverters connected to a weak grid. It is revealed that the cause of the transient instabilities, either high-frequency or low-frequency oscillations, is dominated by the outer control loops and the grid strength. However, most challenging oscillations are low-frequency oscillations induced by coupling interaction between the outer loop controller and PLL (Phase-Locked Loop) when the inverter is connected to a weak grid. Therefore, the paper proposes a low-frequency damping methodology in order to enhance the high system integration, while maintaining the stability of the system. The control method uses a DC link voltage error to modulate the reference reactive current. The proposed control reduces the low-frequency coupling between the DVC (DC link voltage controller), AVC (AC voltage controller) and PLL (Phase-locked loop). According to this study’s results, the performance capability of the grid-connected PV inverter is improved and flexibility in the outer loop controller design is enhanced. The control strategy proposed in this paper is tested using the PLECS simulation software (Plexim GmbH, Zurich Switzerland) and the results are compared with the conventional method.
The Effect of Seed Size on Germination and Seedling Growth in Sweet Chestnut (Castanea sativa Mill.)
Authors: Tumpa Katarina , Vidaković Antonio , Drvodelić Damir , Šango Mario , Idžojtić Marilena , Perković Ivan , Poljak Igor
Published: June 2021

The quantity and quality of seedlings in the nursery has an impact on the success of re-establishment and later growth. High germination rates enable a sufficient number of seedlings, and their quality is assessed using a number of parameters, including seedling height and root collar diameter. These parameters are influenced in some species by seed size, but the correlation between them is species-specific. The model species in this research was sweet chestnut (Castaneasativa Mill.), and seeds from 12 populations from two distinct biogeographical regions of Croatia were collected. We examined the influence of seed size on four parameters: germination rate, seedling height, root collar diameter and sturdiness quotient. Seed size has been shown to have a positive influence on both seedling height and root collar diameter, whereas no such correlation was noted for germination rate and sturdiness quotient. Significant differences in nut size and seedling growth parameters were found between the Mediterranean and continental populations, with higher values observed in the coastal Mediterranean populations. We concluded that seed origin and seed size have a significant impact on seedling growth and are important factors to consider when choosing seed material. Further nursery operations should consider seed origin and local environmental conditions when choosing seedlings for reforestation efforts and general forest operations.
Distribution of Safety Messages Using Mobility-Aware Multi-Hop Clustering in Vehicular Ad Hoc Network
Authors: Chiluveru Rajeshwari , Gupta Nishu , Teles Ariel Soares
Published: June 2021

Reliability and security when distributing safety messages among vehicles in an extremely mobile environment are prominent issues in Vehicular Ad-Hoc Networks (VANETs). In VANET, data transfer becomes challenging because of inherent features such as excessive speed, geographically constrained topologies, unsteady communication links, diversity in the capacity of the channel, etc. A major challenge in the multi-hop framework is maintaining and building a path under such a rigid environment. With VANET, potency in the traffic safety applications has performed well because of the proper design of medium access control (MAC) protocols. In this article, a protocol is proposed pertaining to the distribution of safety messages named mobility-aware multi-hop clustering-based MAC (MAMC-MAC) to accomplish minimum communication overhead, high reliability, and delivery of safety messages in real-time environments. MAMC-MAC has the ability to establish clustering-based multi-hop sequence using the time-division multiple access (TDMA) technique. The protocol was specially developed for highway outlines to achieve network enhancement and efficient channel usage and guarantees integrity among the vehicles. The performance of the proposed protocol is evaluated using Network Simulator (NS-2), and it demonstrates its superiority over various standard protocols in terms of a number of quality-of-service (QoS)-based parameters. The criteria to select and assess these parameters are their sensitivity and importance to the safety-based applications they provide.
Insight of Numerical Simulation for Current Circulation on the Steep Slopes of Bathymetry and Topography in Palu Bay, Indonesia
Authors: Lutfi Mohammad
Published: June 2021

The steep slope of the bathymetry and topography that surrounds Palu Bay is a unique morphology of the area that affects the currents. A simulation was carried out in three regions with seven scenarios to understand the effect of wind, tide, and discharge on currents. The results showed that the average current pattern in Palu Bay is more dominantly influenced by tides at the open boundary and in the middle of the bay, steered by wind directions. The velocity decreases when it reaches the end of the bay and eventually reverses back to the mouth of the bay through both sides of the bay. The current in the Palu River estuary with a discharge of 36 m3/s moves out of the river mouth. On the other hand, results with a discharge of 2 m3/s revealed that the tidal current in the middle layer to the lower layer moves in the opposite direction to the current generated by the discharge in the layer above. It means that the tidal current velocity is lower than that generated by the river discharge. The computation revealed a good agreement with observed current velocity at the selected observation points.
Identification of Erythromycin and Clarithromycin Metabolites Formed in Chicken Liver Microsomes Using Liquid Chromatography–High-Resolution Mass Spectrometry
Authors: Wang Bo , Nam Soyeon , Kim Eunyeong , Jeon Hayoung , Lee Kiho , Xie Kaizhou
Published: June 2021

Nontargeted analysis can be used for the rapid screening and confirmatory analysis of veterinary drugs and their metabolites, which are important for the comprehensive safety evaluation of animal-derived foods. Here, a novel nontargeted screening approach based on liquid chromatography coupled with electrospray ionization–high-resolution mass spectrometry (LC/ESI–HR-MS) was developed to determine erythromycin, clarithromycin, and their metabolites in chicken liver microsomes. Erythromycin and clarithromycin were incubated in vitro in the presence of NADPH for 60 min to generate metabolites in chicken liver microsomes. After the incubation, the supernatant was extracted using ultrasonic shaking, orbital shaking, and centrifugation before analysis using LC/ESI-HR-MS in positive ion mode on an Agilent Eclipse Plus C18 column (100 mm × 2.1 mm; i.d. 3.5 µm) with 0.1 percent formic acid-water and acetonitrile as the mobile phases for gradient elution at 0.4 mL/min. The results show that erythromycin can produce N-desmethyl-erythromycin A in chicken liver microsomes, but clarithromycin cannot produce N-desmethyl-clarithromycin in chicken liver microsomes. The N-desmethyl-erythromycin A and N-desmethyl-clarithromycin were tentatively identified in chicken liver microsomes using the established quick analytic method, which will provide a theoretical foundation for future research on pharmacokinetics and drug elimination in poultry.
Partial Characterization of the Impact of Saffron on the Sensory and Physicochemical Quality Traits of Dry-Cured Ham
Authors: Gómez-Sáez Elena M. , Moratalla-López Natalia , Alonso Gonzalo L. , Vergara Herminia
Published: June 2021

This study determined the effect of adding three concentrations of saffron (A: high, B: medium, and C: low) on vacuum-packaged dry-cured ham slices. The pH and the color coordinates were assessed at 0, 7, 14, 28 and 60 days of storage, and sensorial quality (visual appearance, odor and flavor) and safranal content were analyzed at 7, 14, 28 and 60 days. Saffron concentration did not significantly affect the pH or color (except in a* (redness) and b* (yellowness) at day 28; p < 0.001). Storage period affected pH values (p < 0.001) in all groups with a significant decline from day 28 (p < 0.05); the color coordinates showed a high stability (only L* (lightness) varied in the C group samples; p < 0.01). Sensorial quality did not vary with the time in any group. Significant differences were found among groups in visual appearance (p < 0.05) and flavor (p < 0.001) at day 14 and in odor at day 14, 28, and 60. In general, the C group samples obtained the highest scores. Safranal content varied significantly with the time in a different way in each group, with differences among groups at day 14 and 60 (p < 0.001).
Comprehensive Evaluation of Volatile and Nonvolatile Compounds in Oyster Cuts of Roasted Lamb at Different Processing Stages Using Traditional Nang Roasting
Authors: Xu Yujun , Zhang Dequan , Liu Huan , Wang Zhenyu , Hui Teng , Sun Jilu
Published: June 2021

Nang roasting is a traditional lamb processing method in Xinjiang (China) with a history of thousands of years. This study comprehensively evaluated the volatile and nonvolatile compounds of oyster cuts of roasted lamb at different processing stages of Nang roasting using gas chromatography mass spectrometry and amino acid automatic analyzer, respectively. Results indicated that aldehydes were the dominant profiles of volatile compounds, and hexanal, nonanal, octanal, (E)-2-nonenal, (E, E)-2,4-decadienal, (E, E)-2,4-nonadienal and 1-octen-3-ol were the key volatile compounds or aroma contributors to roasted oyster cuts. Isoamylol and 3-hydroxy-2-butanone could differentiate fresh and marinated oyster cuts from roasted ones; (E)-2-nonenal, (E, E)-2,4-decadienal, 1-octen-3-ol, hexanal, octanal, nonanal and (E, E)-2,4-nonadienal could differentiate Nang roasted oyster cuts of 60 min from those of 15, 30 and 45 min. Umami amino acids and sweet amino acids are the dominant profiles of nonvolatile compounds; glutamic acid, alanine and 5′-IMP were the key free amino acids or taste contributors to roasted oyster cuts. Glutamic acid, alanine and 5′-IMP could differentiate fresh and marinated oyster cuts from roasted samples. This work provided theoretical support for the control of flavor attributes of roasted lamb with traditional Nang roasting.
Synovium-Synovial Fluid Axis in Osteoarthritis Pathology: A Key Regulator of the Cartilage Degradation Process
Authors: Ingale Dhanashri , Kulkarni Priya , Electricwala Ali , Moghe Alpana , Kamyab Sara , Jagtap Suresh , Martson Aare , Koks Sulev , Harsulkar Abhay
Published: June 2021

Failure of conventional anti-inflammatory therapies in osteoarthritis (OA) underlines the insufficient knowledge about inflammatory mechanisms, patterns and their relationship with cartilage degradation. Considering non-linear nature of cartilage loss in OA, a better understanding of inflammatory milieu and MMP status at different stages of OA is required to design early-stage therapies or personalized disease management. For this, an investigation based on a synovium-synovial fluid (SF) axis was planned to study OA associated changes in synovium and SF along the progressive grades of OA. Gene expressions in synovial-biopsies from different grades OA patients (N = 26) revealed a peak of IL-1β, IL-15, PGE2 and NGF in early OA (Kellgren–Lawrence (KL) grade-I and II); the highest MMP levels were found in advanced stages (KL grade-III and IV). MMPs (MMP-1, 13, 2 and 9) abundance and FALGPA activity estimated in forty SFs of progressive grades showed the maximum protein levels and activity in KL grade-II and III. In an SF challenge test, SW982 and THP1 cells were treated with progressive grade SFs to study the dynamics of MMPs modulation in inflammatory microenvironment; the test yielded a result pattern, which matched with FALGPA and the protein-levels estimation. Inflammatory mediators in SFs served as steering factor for MMP up-regulation. A correlation-matrix of IL-1β and MMPs revealed expressional negative correlation.