bluuebunny/crossref_metadata_2025 huggingface dataset:
Monitoring Spatiotemporal Distribution of the GDP of Major Cities in China during the COVID-19 Pandemic
Authors: Wang Yanjun , Teng Fei , Wang Mengjie , Li Shaochun , Lin Yunhao , Cai Hengfan
Published: July 2022

Monitoring the fine spatiotemporal distribution of urban GDP is a critical research topic for assessing the impact of the COVID-19 outbreak on economic and social growth. Based on nighttime light (NTL) images and urban land use data, this study constructs a GDP machine learning and linear estimation model. Based on the linear model with better effect, the monthly GDP of 34 cities in China is estimated and the GDP spatialization is realized, and finally the GDP spatiotemporal correction is processed. This study analyzes the fine spatiotemporal distribution of GDP, reveals the spatiotemporal change trend of GDP in China’s major cities during the current COVID-19 pandemic, and explores the differences in the economic impact of the COVID-19 pandemic on China’s major cities. The result shows: (1) There is a significant linear association between the total value of NTL and the GDP of subindustries, with R2 models generated by the total value of NTL and the GDP of secondary and tertiary industries being 0.83 and 0.93. (2) The impact of the COVID-19 pandemic on the GDP of cities with varied degrees of development and industrial structures obviously varies across time and space. The GDP of economically developed cities such as Beijing and Shanghai are more affected by COVID-19, while the GDP of less developed cities such as Xining and Lanzhou are less affected by COVID-19. The GDP of China’s major cities fell significantly in February. As the COVID-19 outbreak was gradually brought under control in March, different cities achieved different levels of GDP recovery. This study establishes a fine spatial and temporal distribution estimation model of urban GDP by industry; it accurately monitors and assesses the spatial and temporal distribution characteristics of urban GDP during the COVID-19 pandemic, reveals the impact mechanism of the COVID-19 pandemic on the economic development of major Chinese cities. Moreover, economically developed cities should pay more attention to the spread of the COVID-19 pandemic. It should do well in pandemic prevention and control in airports and stations with large traffic flow. At the same time, after the COVID-19 pandemic is brought under control, they should speed up the resumption of work and production to achieve economic recovery. This study provides scientific references for COVID-19 pandemic prevention and control measures, as well as for the formulation of urban economic development policies.
Role of Toothbrushes as Gene Expression Profiling Tool for Oral Cancer Screening in Tobacco and Alcohol Users
Authors: Sujatha Govindarajan , Veeraraghavan Vishnu Priya , Alamoudi Ahmed , Bahammam Maha A. , Bahammam Sarah Ahmed , Alhazmi Yaser Ali , Alharbi Hazar S. , Alzahrani Khalid J. , Al-Ghamdi Mohammad S. , Alzahrani Fuad M. , Varadarajan Saranya , Raj A. Thirumal , Patil Shankargouda
Published: July 2022

Aim: The use of toothbrushes was investigated as a potential RNA source and gene expression profiling tool for oral cancer screening in tobacco and alcohol users. Methodology: A total of 20 subjects were selected on the basis of inclusion and exclusion criteria. They were divided into two groups: group I—healthy controls (n = 6); group II—individuals who consume tobacco and alcohol (n = 14). After the volunteers brushed their teeth using a soft-bristle toothbrush with ~0.5 gm of toothpaste, the toothbrushes were collected, and the gene expression of BAX, BCL2, CDK4, CKDN2A, GNB3, and TCF7L2 was assessed. Results: The gene expression of BAX decreased significantly in alcoholics and smokers (0.13867 ± 0.12014), while the gene expression of BCL2 increased in alcoholics and smokers (1.91001 ± 0.90425) in comparison with healthy controls (p = 0.0054 and p = 0.0055). Although there was increased expression of CDK4, CKDN2A, and TCF7L2 and decreased expression of GNB3 in smokers and alcoholics, the results were not significant. Conclusions: A toothbrush is a good source of RNA, and gene expression analysis can be performed using the genetic material retrieved from toothbrushes, which can aid in the early diagnosis of oral squamous cell carcinoma among tobacco and alcohol users. Further studies with a larger sample size and different durations of toothbrush use should be conducted to explore the role of toothbrushes as a noninvasive tool for disease diagnosis.
Trends in Hospital Admissions Due to Neoplasms in England and Wales between 1999 and 2019: An Ecological Study
Authors: Naser Abdallah Y. , Alwafi Hassan , Hemmo Sara Ibrahim , Alrawashdeh Hamzeh Mohammad , Alqahtani Jaber S. , Alghamdi Saeed M. , Mustafa Ali Moaath K.
Published: July 2022

Objectives: This study aimed to investigate the trends in neoplasm-related hospital admissions (NRHA) in England and Wales between 1999 and 2019. Methods: This is an ecological study using publicly available data taken from the two main medical databases in England and Wales; the Hospital Episode Statistics database in England and the Patient Episode Database in Wales. Hospital admissions data were collected for the period between April 1999 and March 2019. Results: A total of 35,704,781 NRHA were reported during the study period. Females contributed to 50.8% of NRHA. The NRHA rate among males increased by 50.0% [from 26.62 (95% CI 26.55–26.68) in 1999 to 39.93 (95% CI 39.86–40.00) in 2019 per 1000 persons, trend test, p < 0.001]. The NRHA rate among females increased by 44.1% [from 27.25 (95% CI 27.18–27.31) in 1999 to 39.25 (95% CI 39.18–39.32) in 2019 per 1000 persons, trend test, p < 0.001]. Overall, the rate of NRHA rose by 46.2% [from 26.93 (95% CI 26.89–26.98) in 1999 to 39.39 (95% CI 39.34–39.44) in 2019 per 1000 persons, trend test, p < 0.001]. Conclusion: Hospital admission rates due to neoplasms increased between 1999 and 2019. Our study demonstrates a variation in NRHA influenced by age and gender. Further observational studies are needed to identify other factors associated with increased hospital admissions among patients with different types of neoplasms.
Parent Intention to Enroll in an Online Intervention to Enhance Health Behavior Change among Youth Treated with Psychotropic Medication Who Are Overweight or Obese: An Elicitation Study
Authors: Richardson Kathryn A. , McKibbin Christine L. , Dabrowski Barbara S. , Punke Elizabeth L. A. , Hartung Cynthia M.
Published: July 2022

Youth who are prescribed psychotropic medication are disproportionally affected by overweight/obesity (OW/OB), yet few interventions have been tailored to their needs. To develop new interventions, it is important to address the needs, preferences, and intentions of target users. Qualitative methods within the theory of planned behavior (TPB) framework were used in this study to identify salient beliefs which may influence attitudes associated with parents’ intentions to participate in a future online intervention designed to develop behavioral health coaching skills among parents and guardians. Twenty parents and guardians of youth with OW/OB who were taking psychotropic medications, and were eligible for the study, were recruited through TurkPrime. Parents and guardians identified key salient beliefs consistent with the theory of planned behavior including behavioral beliefs (e.g., access and convenience), normative beliefs (e.g., family), and control beliefs (e.g., cost) that may influence their decision to enroll in a future, parent-oriented intervention. The results of this study suggest important salient beliefs which may be included in future research, as well as specific preferences which may be used to guide the development of a future intervention. Future work should focus on the creation of a salient belief quantitative measure and assess the relationships of these beliefs to attitudinal constructs and behaviors.
Can Intra-Oral Qualitative Sensory Testing Foretell Postoperative Dental Pain? A Preliminary Report
Authors: Emodi-Perlman Alona , Altarescu Deia , Frideman-Rubin Pessia , Eli Ilana
Published: July 2022

Pain prevention and management is one of the primary goals of dental care. Postoperative dental pain (PDP) following caries removal and performance of a restorative dental treatment is a common clinical phenomenon, often causing significant discomfort to dental patients. In the present study, a psychophysical non-invasive method, qualitative sensory testing (QualST), was used in an attempt to foretell PDP following dental restorative procedures. Forty-two dental patients underwent an intra-oral cold QualST four times: immediately prior to a restorative dental procedure and at a follow-up meeting 1–3 weeks later, on the treated and on the contralateral oral sides. The QualST measures included subjects’ evaluation of the magnitude of pain and cold sensations experienced (on visual analogue scales) and the duration of the cold sensation (in seconds). Additional measures included age, gender, level of dental anxiety, jaw treated, and type of dental restoration performed (Class I or Class V). Subjects’ PDP was assessed through the phone using numeric rating scales 24, 48, and 72 h postoperatively. The highest level of PDP experienced by subjects occurred 24 h postoperatively (ANOVA with repeated measures). Of the study variables, the QualST pain sensation (B = 0.645, p < 0.001), duration of the cold sensation (B = 0.042, p < 0.05), and an interaction between gender and dental anxiety (B = 0.136, p < 0.05) emerged as possible predictors of the highest PDP experienced by subjects (stepwise regression). The results suggest that subjects’ reaction to an intra-oral cold stimulation of the oral mucosa can serve as a potential tool to foretell postoperative dental pain following restorative dental procedures.
Affective Neuroscience Personality Scales and Early Maladaptive Schemas in Depressive Disorders
Authors: Talarowska Monika , Wysiadecki Grzegorz , Chodkiewicz Jan
Published: July 2022

Aim: The aim of this study was to assess the interrelationships of Young’s early maladaptive schemas with indicators of specific neural emotional systems conceptualized in Panksepp’s theory in a group of people suffering from depressive disorders. Materials and methods: The Affective Neuroscience Personality Scales (ANPS) v. 2.4. and J. Young’s Early Maladaptive Schema Questionnaire (YSQ-S3-PL) were used. Ninety (90) individuals aged 18–58, including 45 people treated for depression (DD group), were qualified to participate in the experiment. Results: The subjects in the DD group scored statistically significantly lower than the subjects from the control group (CG group) on the three ANPS scale domains, namely SEEKING, PLAY, and ANGER. The subjects with depressive symptoms scored significantly higher in the YSQ-S3-PL questionnaire on two domains of early maladaptive schemas, i.e., “Impaired autonomy and performance” and “Other-directedness”. Regression analysis results indicate that impairment of the emotional SEEKING system explains most of the variability in the following typical domains of depression: “Disconnection and rejection”, “Impaired autonomy and performance”, and “Other-directedness”. For score variability in the domain area of “Impaired limits”, the ANGER system was found to be most significant, and the FEAR system proved the same for “Overvigilance and Inhibition”. Conclusions: 1. Two domains of early maladaptive schemas are significant for the onset of depressive symptoms, namely “Impaired autonomy and performance” and “Other-directedness”, linked to difficulties in engaging in behaviors to meet one’s own needs. 2. Impairment of the neural emotional SEEKING system most significantly explains the variability in depression-typical areas of early maladaptive schemas.
Construction and Optimization of an Ecological Network in Zhengzhou Metropolitan Area, China
Authors: Huo Jingeng , Shi Zhenqin , Zhu Wenbo , Li Tianqi , Xue Hua , Chen Xin , Yan Yanhui , Ma Ran
Published: July 2022

Rapid urbanization aggravates issues related to protection and optimization of the ecological environment. Constructing an ecological network system, including ecological values in planning, and using landscape effects efficiently are important for adjusting regional ecological space and promoting local sustainable development. Land use data from eight time points between 1980 and 2020 in the Zhengzhou Metropolitan Area were used to identify the local ecological sources, corridors and nodes and to identify an ecological network with high structural integrity. The study used the FLUS, MSPA, MCR, and gravity models, hydrological analysis, and network structure evaluation by applying tools such as ArcGIS, Guidos Toolbox and Conefor. The results indicated that: (1) among the nine major ecological sources, those in the Yellow River Basin connected the large−scale sources in the east and west of the network, and the rest were located in the northeast, southeast and southwest of the research area, semi−enclosing the main urban area of Zhengzhou. (2) There were 163 least−cost paths and 58 ecological corridors, mainly distributed along the Yellow River Basin. (3) There were 70 ecological nodes, divided into 10 strategic, 27 natural ecological and 33 artificial environment nodes, distributed in key locations such as the core of each source and the intersection of corridors. (4) The ecological network included all the landscape elements in the research area and connected the main ecological substrates in a semi−enclosing network structure with one horizontal and two vertical corridors and four clusters.
Identifying the Relationship between Leisure Walking and Prevalence of Alzheimer’s Disease and Other Dementias
Authors: Kim Junhyoung , Lee Jungjoo , Kim Yu-Sik , Park Se-Hyuk
Published: July 2022

The literature suggests that leisure walking can play an important role in preventing dementia. The purpose of the present study was to investigate the relationship between leisure walking and the prevalence of Alzheimer’s disease (AD) and other dementias among older adults. Using the 2020 Health and Retirement Study (HRS), 4581 responses constituted the sample for the present study. A hierarchical logit regression analysis was conducted to investigate the relationship between leisure walking and the prevalence of AD and dementia. The results show that leisure walking has been negatively associated with the prevalence of AD and other dementias—that is, they indicate that older adults who frequently engaged in leisure walking were less likely to develop AD and other dementias. This finding suggests the importance of leisure walking as a dementia prevention program for older adults.
Learning from Incidents in Socio-Technical Systems: A Systems-Theoretic Analysis in the Railway Sector
Authors: Nakhal Akel Antonio Javier , Di Gravio Giulio , Fedele Lorenzo , Patriarca Riccardo
Published: July 2022

Post mortem incident investigations are vital to prevent the occurrence of similar events and improve system safety. The increasing interactions of technical, human and organizational elements in modern systems pose new challenges for safety management, demanding approaches capable of complementing techno-centric investigations with social-oriented analyses. Hence, traditional risk analysis methods rooted in event-chain reactions and looking for individual points of failure are increasingly inadequate to deal with system-wide investigations. They normally focus on an oversimplified analysis of how work was expected to be conducted, rather than exploring what exactly occurred among the involved agents. Therefore, a detailed analysis of incidents beyond the immediate failures extending towards socio-technical threats is necessary. This study adopts the system-theoretic accident model and process (STAMP) and its nested accident analysis technique, i.e., causal analysis based on systems theory (CAST), to propose a causal incident analysis in the railway industry. The study proposes a hierarchical safety control structure, along with system-level safety constraints, and detailed investigations of the system’s components with the purpose of identifying physical and organizational safety requirements and safety recommendations. The analysis is contextualized in the demonstrative use of a railway case. In particular, the analysis is instantiated for a 2011 incident in the United Kingdom (UK) railway system. Hence, the CAST technique requires information regarding incidents, facts and processes. Therefore, the case study under analysis provided the information to analyze the accidents based on system theory, in which the results of the analysis prove the benefits of a CAST application to highlight criticalities at both element- and system-level, spanning from component failure to organizational and maintenance planning, enhancing safety performance in normal work practices.
TiO2/Au/TiO2 Plasmonic Photocatalysts: The Influence of Titania Matrix and Gold Properties
Authors: Yoshiiri Kenta , Wang Kunlei , Kowalska Ewa
Published: July 2022

Plasmonic photocatalysts have gained more and more attention because of possible applications for solar energy conversion, environmental decontamination, and water treatment. However, the activity under visible light is usually very low, and the property-governed activity as well as the mechanisms are not fully understood yet. Accordingly, this study examines four different titania photocatalysts (anatase and rutile with fine and large crystallites) modified with gold by photodeposition. Three kinds of samples were prepared, as follows: (i) gold-modified titania (Au/TiO2), (ii) physically mixed Au/TiO2 samples (Au/TiO2(1) + Au/TiO2(2)), and (iii) Au/(TiO2(1) + Au/TiO2(2)) samples, prepared by subsequent deposition of gold on the mixture of bare and gold-modified titania. In total, twelve samples were prepared and well characterized, including diffuse reflectance spectroscopy (DRS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning transmission electron microscopy (STEM). The photocatalytic activity was examined in three reaction systems: (i) methanol dehydrogenation during gold photodeposition under UV/vis irradiation, (ii) oxidative decomposition of acetic acid (UV/vis), and (iii) oxidation of 2-propanol to acetone under visible light irradiation (λ > 450 nm). It was found that during subsequent deposition, gold is mainly formed on the surface of pre-deposited Au nanoparticles (NPs), localized on fine titania NPs, through the electrostatic attractions (negatively charged gold resulting from photogenerated electrons’ accumulation). This gold aggregation, though detrimental for UV activity (many “naked” large titania with low activity), is highly beneficial for vis activity because of efficient light harvesting and increased interface between gold and titania (gold deposits surrounded by fine titania NPs). Moreover, it was found that rutile is more active than anatase for plasmonic photocatalysis, probably due to easier electron transfer from gold via titania to adsorbed oxygen (more negative conduction band), which might hinder the back reaction (electron transfer: Au→TiO2→Au).
A Dynamic Obstacle Avoidance Method for Unmanned Surface Vehicle under the International Regulations for Preventing Collisions at Sea
Authors: Gao Diju , Zhou Peng , Shi Weifeng , Wang Tianzhen , Wang Yide
Published: July 2022

A new method is proposed for the dynamic obstacle avoidance problem of unmanned surface vehicles (USVs) under the international regulations for preventing collisions at sea (COLREGs), which applies the particle swarm optimization algorithm (PSO) to the dynamic window approach (DWA) to reduce the optimal trajectory finding the time and improve the timeliness of obstacle avoidance. Meanwhile, a fuzzy control algorithm is designed to dynamically adjust the weight coefficients of the velocity and obstacle distance terms in the cost function of the DWA algorithm to adapt to the changes in the environment. The proposed dynamic obstacle avoidance method is experimentally validated, in which proposed PSO combined with the DWA algorithm (PSO-CCDWA) results in a 42.1%, 11.2% and 28.0% reduction in the navigation time of the USVs in three encounter-situations of COLREGs than that of the classical DWA algorithm (CCDWA) conforming to the conventional COLREGs, respectively. The fuzzy control combined with the DWA algorithm (FUZZY-CCDWA) reduces the distance traveled by 15.8%, 0.9% and 2.8%, respectively, over the CCDWA algorithm in the three encounter scenarios. Finally, the effectiveness of the proposed dynamic obstacle avoidance method is further verified in a practical navigation experiment of a USV named “Buffalo”.
Lateral Variation of Tidal Mixing Asymmetry and Its Impact on the Longitudinal Sediment Transport in Turbidity Maximum Zone of Salt Wedge Estuary
Authors: Teng Lizhi , Cheng Heqin , Zhang Erfeng , Wang Yajun
Published: July 2022

The lateral bathymetry in the estuary results in different degrees of tidal mixing asymmetry, which has significant impacts on the longitudinal sediment transport by changing the temporal variation of vertical eddy diffusion. This study focus on the lateral variation of tidal mixing asymmetry and longitudinal sediment transport at the landward boundary of turbidity maximum zone in the North Channel of Yangtze estuary, which is a typical time-dependent salt wedge estuary. A transect survey was carried out in December, 2018; five vertical profiles of flow velocity, salinity and suspended sediment concentration were simultaneously measured covering a spring tidal cycle. Analysis of the data revealed that, after the maximum ebb, the stratification in the main and secondary channel was stronger than that on the shoal. In the channel, during ebb tide, the stronger stratification restrained the turbulent mixing induced by vertical shear, vertical mixing during the flood tide was stronger than that during ebb tide and vertical mixing coefficients ranged from 0.06 to 0.12, showing regular tidal mixing asymmetry over a flood–ebb tidal cycle. Therefore, stronger eddy diffusion caused by vertical mixing resulted in higher suspended sediment concentrations during flood tide, the larger landward tidally averaged sediment transport rate was induced by tidal pumping with the transportation of flood tidal current and the net sediment transport over a flood–ebb tidal cycle in the channel was landward. Meanwhile, on the shoal, under the effect of vertical shear, the vertical mixing during flood tide was weaker than that during ebb tide; vertical mixing coefficients ranged from −0.27 to −0.02, showing the reversed tidal mixing asymmetry. Higher suspended sediment concentration was transported seaward by the ebb current, the tidally averaged sediment transport rate by both tidal pumping and advection was seaward and the net sediment transport was seaward. Furthermore, large river discharge increased the seaward advection sediment flux on the surface layer in the main channel, resulting in the seaward tidally averaged sediment flux. Strong resuspension increased the seaward advection sediment flux near the bottom in the main and secondary channel, resulting in the seaward tidally averaged sediment flux.
Air Sampling for Fungus around Hospitalized Patients with Coronavirus Disease 2019
Authors: Chen Yi-Chun , Lin Yin-Shiou , Kuo Shu-Fang , Lee Chen-Hsiang
Published: July 2022

The risk of developing coronavirus disease 2019 (COVID-19)-associated pulmonary aspergillosis (CAPA) depends on factors related to the host, virus, and treatment. However, many hospitals have modified their existing rooms and adjusted airflow to protect healthcare workers from aerosolization, which may increase the risk of Aspergillus exposure. This study aimed to quantitatively investigate airborne fungal levels in negative and slightly negative pressure rooms for COVID-19 patients. The air in neutral pressure rooms in ordinary wards and a liver intensive care unit with high-efficiency particulate air filter was also assessed for comparison. We found the highest airborne fungal burden in recently renovated slightly negative air pressure rooms, and a higher airborne fungal concentration in both areas used to treat COVID-19 patients. The result provided evidence of the potential environmental risk of CAPA by quantitative microbiologic air sampling, which was scarcely addressed in the literature. Enhancing environmental infection control measures to minimize exposure to fungal spores should be considered. However, the clinical implications of a periodic basis to determine indoor airborne fungal levels and further air sterilization in these areas remain to be defined.
Influence of Meso-Scale Pore Structure on Mechanical Behavior of Concrete under Uniaxial Compression Based on Parametric Modeling
Authors: Yang Hao , Zhu Eryu , Liu Lei
Published: July 2022

Existing concrete random aggregate modeling methods (CRAMMs) have deficiencies in in the parameterization of the mesoscale pore structure. A novel CRAMM is proposed, whose pore structure is determined by the pore gradation, total porosity, sub-porosity, and pore size of each pore gradation segment. To study the influence of pore structure on the mechanical properties of concrete, 25 mesoscopic concrete specimens with the same aggregate structure but different meso-scale pore structures are constructed and subjected to uniaxial compression tests. For the first time, the influence of sub-porosity of each pore gradation segment, average pore radius (APR), pore specific surface area (PSSA), and total porosity on concrete failure process, compressive strength, peak strain, and elastic modulus were quantitatively and qualitatively analyzed. Results indicate that the pore structure makes the germination and propagation of the damage in cement mortar show obvious locality and affects the formation and expansion of macroscopic cracks. However, it does not accelerate the propagation of the damage in cement mortar from the periphery to the center of the specimen, nor does it change the phenomenon that the ITZ is more damaged than other meso-components of concrete before peak stress. Macroscopic cracks occur in the descending section of the stress–strain curve, and the sudden drops in the descending section of the stress–strain curve are often accompanied by the generation and expansion of macroscopic cracks. The quadratic polynomial, exponential, and power functions can well fit the relationship between total porosity and compressive strength and the relationship between PSSA and compressive strength. The linear, exponential, and power functions can well reflect the relationship between total porosity and compressive modulus and the relationship between compressive modulus and PSSA. For concrete specimens with the same total porosity, the elastic modulus and strength show randomness with the increase in the sub-porosity of macropores and are basically not affected by the APR. Based on the grey relational analysis, the effects of pore structure parameters on the elastic modulus and compressive strength are in the same order: total porosity > T [k1,k2] > T [k2,k3] > T [k3,k4] > T [k4,k5] > AVR > PSSA. The order of influence of the pore structure parameters on the peak strain is: T [k2,k3] > T [k1,k2] > T [k3,k4] > T [k4,k5] > APR > PSSA > total porosity.
Investigation of Thermal-Induced Changes in Molecular Order on Photopolymerization and Performance Properties of a Nematic Liquid-Crystal Diacrylate
Authors: Wang Qian , Wellinghoff Stephen T. , Rawls Henry Ralph
Published: July 2022

Polymerization shrinkage and associated stresses are the main reasons for dental restorative failure. We developed a series of liquid crystal diacrylates and dimethacrylates which have markedly low polymerization shrinkage. In order to fully understand the effects of temperature-induced changes of molecular order on the photopolymerization process and performance properties of the generated polymers, the photopolymerization of a difunctional acrylate, 2-t-butyl-1,4-phenylene bis (4-(6-(acryloyloxy)hexyloxy)benzoate), which exists in the nematic liquid crystalline phase at room temperature, was investigated as a function of photopolymerization temperature over the nematic to isotropic range. Morphological studies suggested that a mesogenic phase was immediately formed in the polymer even if polymerization in thin films occurred above the nematic-to-isotropic (N→I) transition temperature of the monomer (Tn-i = 45.8 °C). Dynamic mechanical analysis of 2 × 2 mm cross-section bar samples polymerized at 60 °C showed reduced elastic moduli, increased glass transition temperature and formation of a more crosslinked network, in comparison to polymers formed at lower polymerization temperatures. Fractography analysis showed that polymers generated from the nematic liquid crystalline phase underwent a different fracture pattern in comparison to those generated from the isotropic phase. Volumetric shrinkage (2.2%) found in polymer polymerized from the nematic liquid crystalline phase at room temperature was substantially less than the 6.0% observed in polymer polymerized from an initial isotropic phase at 60 °C, indicating that an organized monomer can greatly contribute to reducing cure shrinkage.
Fluorinated Agents Effects on Orthodontic Alloys: A Descriptive In Vitro Study
Authors: Condò Roberta , Carli Elisabetta , Cioffi Alessandro , Cataldi Maria Elena , Quinzi Vincenzo , Casaglia Adriano , Giancotti Aldo , Pirelli Paola , Lucarini Ivano , Maita Francesco , Maiolo Luca , Mampieri Gianluca
Published: July 2022

Fluoride-based mouthwashes and gels are preventive measures in countering demineralization and caries but, modifying environmental acidity, can reduce the wet corrosion resistance of orthodontic alloys. To evaluate chemical stability, in vitro experiments were conducted on stainless steel and nickel–titanium wires, weighed before and after immersion in household fluorinated mouthwashes and gels, measuring weight variations and elution of metal ions from acid corrosion phenomena. Elution samples were analyzed by inductively coupled plasma mass spectrometry, detecting residual ion concentration, while surface changes were analyzed under scanning electron microscopy. Results showed stainless steel wires do not undergo significant erosion when exposed to most fluorinated mouthwashes but, at prolonged exposure, alloys elute gradually greater amounts of metals and Ni–Ti wires become more sensitive to some mouthwashes. Ions’ elution varies considerably, especially for Ni–Ti wires, if exposed to household fluorinated gels, for which significant negative values were obtained. Changes, affecting wires’ outer layer, negatively act on shiny appearance and luster, reducing corrosion resistance. Although examined orthodontic wires showed good chemical stability and low toxicity, surface corrosion from exposure to fluorinated agents was observed. Home use must be accompanied by clinician prescription and, for household dental gels, must follow manufacturers’ recommendations, ensuring prophylactic action without damaging alloys surfaces.
Fundamental Studies on Crystallization and Reaching the Equilibrium Shape in Basic Ammonothermal Method: Growth on a Native Lenticular Seed
Authors: Sochacki Tomasz , Kucharski Robert , Grabianska Karolina , Weyher Jan L. , Iwinska Malgorzata , Bockowski Michal , Kirste Lutz
Published: July 2022

In this paper, a detailed investigation of the basic ammonothermal growth process of GaN is presented. By analyzing the crystallization on a native seed with a lenticular shape, thus with an intentionally varying off-cut, we wanted to answer some basic questions: (i) Which crystallographic planes play the most important role during growth (which planes are formed and which disappear)? (ii) What is the relationship between the growth rates in different crystallographic directions? (iii) What is the influence of the off-cut of the seed on the growth process? Two non-polar slices, namely, 12¯10 and 1¯100, as well as a 0001 basal plane slice of an ammonothermal crystal were analyzed. The examined planes were selectively etched in order to reveal the characteristic features of the growth process. The applied characterization methods included: optical microscopy with Nomarski contrast and ultraviolet illumination, X-ray topography and high-resolution X-ray diffraction, and secondary ion mass spectrometry. The obtained results allowed for creating a growth model of an ammonothermal GaN crystal on a lenticular seed. These findings are of great importance for the general understanding of the basic ammonothermal crystal growth process of GaN.
Non-Separable Meyer-like Wavelet Frames
Authors: Zhang Zhihua
Published: July 2022

In the theory of wavelet frames, the known Daubechies wavelet bases have been generalized to compactly supported (Daubechies-like) wavelet frames, while the known bandlimited Meyer wavelet bases have not been generalized to date. In this study, we will generalize known Meyer wavelet basis into non-separable Meyer-like wavelet frames. By using a characteristic function to mask the Fourier transform of the one-dimensional Meyer scaling function with a width parameter, we can produce a family of Meyer-like frame scaling functions and associated Meyer-like wavelet frames. After that, by inserting a real-valued function into the width parameter of a one-dimensional Meyer-like frame scaling function, we propose a novel approach to construct non-separable Meyer-like frame scaling functions with unique circular symmetry. Finally, we construct the corresponding non-separable Meyer-like wavelet frames.
Dimensionality Analysis of Entrepreneurial Resilience amid the COVID-19 Pandemic: Comparative Models with Confirmatory Factor Analysis and Structural Equation Modeling
Authors: Elshaer Ibrahim A.
Published: July 2022

Several previous empirical research studies have defined and operationalized entrepreneurial resilience (ENTR-RISC) as either a construct with multiple dimensions or a construct with a single dimension. While only a few previous research studies have assessed some components of the presumed dimensionality of ENTR-RISC, no research has attempted to assess the dimensional structure of ENTR-RISC amid the COVID-19 pandemic using different alternative competing models. In order to acquire a deeper understanding of the dimensional characteristics of the ENTR-RISC construct, this research assessed its dimensionality by comparing existing models’ goodness of fit (GoF), and the best model that fitted the data was further tested using various confirmatory factor analysis (CFA) models (a second-order factor model, an oblique first-factor model, and a single-factor model) on quantitative data gathered from 590 SME entrepreneurs in Kingdom of Saudi Arabia (KSA). The results of analyzing the tested models via structural equation modeling (SEM) and the AMOS program indicated that the ENTR-RISC construct has a multidimensional three-factor structure. Even though this research helps in the advancement of ENTR-RISC practice and theory, further research is required to test the dimensionality of ENTR-RISC in greater depth. The findings of this study may encourage further research on this topic and stimulate a much-needed discussion on the dimensional structure of the ENTR-RISC concept.
Study on Wear Characteristics of Revolute Clearance Joints in Mechanical Systems
Authors: Bai Zhengfeng , Ning Zhiyuan , Zhou Junsheng
Published: July 2022

The existence of clearance causes contact-impact forces in joints, which lead to surface wear and incessant material loss of the joint surface during the motion of mechanisms. In this work, the wear characteristics of dry revolute clearance joints in planar mechanisms are studied using a computational methodology. The normal contact force model and the tangential friction force model are established to describe the contact-impact in clearance joints. Then, the dynamic wear model based on the Archard’s wear model is established to predict the wear characteristics of clearance joints in mechanisms. The dynamic wear depths of clearance joints are obtained in two steps. The first step is the dynamics analysis of mechanisms to obtain the contact and sliding characteristics between the bearing and journal in the clearance joint. The second step is the dynamic wear depth analysis of clearance joints based on dynamic Archard’s wear model. Finally, a planar slider-crank mechanism with two revolute clearance joints between the connecting rod and its adjacent links is used as the implement example. Different case studies are performed to investigate the wear characteristics of clearance joints in mechanical systems.
Circuit Techniques for High Efficiency Piezoelectric Energy Harvesting
Authors: Yang Yi , Chen Zhiyuan , Kuai Qin , Liang Junrui , Liu Jingjing , Zeng Xiaoyang
Published: July 2022

This brief presents a tutorial on multifaceted techniques for high efficiency piezoelectric energy harvesting. For the purpose of helping design piezoelectric energy harvesting system according to different application scenarios, we summarize and discuss the recent design trends and challenges. We divide the design focus into the following three categories, namely, (1) AC-DC rectifiers, (2) CP compensation circuits, (3) maximum power point tracking (MPPT) circuits. The features, problems encountered, and suitable systems of various AC-DC rectifier topologies are introduced and compared. The important role of non-linear methods for piezoelectric energy harvesting is illustrated from the perspective of impedance matching. Energy extraction techniques and voltage flipping techniques based on inductors, capacitors, and hybrid structures are analyzed. MPPT techniques with different features and targets are discussed.
Fabrication of Three-Dimensionally Deformable Metal Structures Using Precision Electroforming
Authors: Kumamoto Seitaro , Fukuyama Souichiro , Nagano Seiya , Yasuda Keiichiro , Kitamura Yusuke , Iwatsuki Masaaki , Baba Hideo , Ihara Toshihiro , Nakanishi Yoshitaka , Nakashima Yuta
Published: July 2022

It is difficult to fabricate three-dimensional structures using semiconductor-process technology, because it is based on two-dimensional layered structure fabrication and the etching of thin films. In this study, we fabricated metal structures that can be dynamically deformed from two-dimensional to three-dimensional shapes by combining patterning using photolithography with electroforming technology. First, a resist structure was formed on a Cu substrate. Then, using a Ni sulfamate electroforming bath, a Ni structure was formed by electroforming the fabricated resist structure. Finally, the resist structure was removed to release the Ni structure fabricated on the substrate, and electroforming was used to Au-plate the entire surface. Scanning-electron microscopy revealed that the structure presented a high aspect ratio (thickness/resist width = 3.5), and metal structures could be fabricated without defects across the entire surface, including a high aspect ratio. The metallic structures had an average film thickness of 12.9 µm with σ = 0.49 µm, hardness of 600 HV, and slit width of 7.9 µm with σ = 0.25 µm. This microfabrication enables the fabrication of metal structures that deform dynamically in response to hydrodynamic forces in liquid and can be applied to fields such as environmental science, agriculture, and medicine.
Tunable Dual-Wavelength with Twin-Pulse Dissipative Solitons in All-Normal Dispersion Yb-Doped Fiber Laser
Authors: Zhu Xiaojun , Liu Wen , Pan Yongquan , Li Shuai , Zhang Guoan , Ji Yancheng , Zou Li , Liang Zhipeng , Cao Juan
Published: July 2022

A tunable dual-wavelength with two separated twin-pulse dissipative solitons (DSs) of Yb-doped mode-locked fiber laser in the all-normal-dispersion (ANDi) regime is firstly reported and demonstrated in this paper. A Sagnac loop is used as an all-fiber format spectral filter in the laser cavity, and stable twin-pulse DSs with different wavelength mode-locked lasers are achieved by the nonlinear polarization evolution (NPE) effect. By adjusting the polarization state of the Sagnac loop, the spectral ranges of the dual-wavelength can be tuned from 1031.3 nm to 1041.5 nm and from 1067.1 nm to 1080.9 nm, respectively. However, the pulse space between the two separated twin-pulse DSs is maintained, i.e., 41.63 ns. Furthermore, the twin-pulse can regress to the single-pulse when the pump power keeps dropping. It has been observed that the highest energy of the two twin-pulse DSs output is 23.36 nJ at a repetition rate of 2.282 MHz with a maximum pump power of 560 mW.
Design of a Radial Vortex-Based Spin-Torque Nano-Oscillator in a Strain-Mediated Multiferroic Nanostructure for BFSK/BASK Applications
Authors: Hu Huimin , Yu Guoliang , Li Yiting , Qiu Yang , Zhu Haibin , Zhu Mingmin , Zhou Haomiao
Published: July 2022

Radial vortex-based spin torque nano-oscillators (RV-STNOs) have attracted extensive attention as potential nano microwave signal generators due to their advantages over other topological states, such as their higher oscillation, higher microwave power, and lower power consumption. However, the current driving the oscillation frequency of the STNOs must be limited in a small range of adjustment, which means less data transmission channels. In this paper, a new RV-STNO system is proposed with a multiferroic nanostructure, which consists of an ultrathin magnetic multilayer and a piezoelectric layer. Phase diagrams of oscillation frequency and amplitude with respect to piezostrain and current are obtained through micromagnetic simulation. The results show that the threshold current density of −4000-ppm compressive strain-assisted RV-STNOs is reduced from 2 × 109 A/m2 to 2 × 108 A/m2, showing one order of magnitude lower than that of conventional current-driven nano-oscillators. Meanwhile, the range of oscillation frequency adjustment is significantly enhanced, and there is an increased amplitude at the low oscillation point. Moreover, a promising digital binary frequency-shift key (BFSK) and binary amplitude-shift key (BASK) modulation technique is proposed under the combined action of current pulse and piezostrain pulse. They can transmit bit signals and show good modulation characteristics with a minimal transient state. These results provide a reference for developing the next generation of spintronic nano-oscillators with a wide frequency range and low power consumption, showing potential for future wireless communication applications.
Warming-Induced Labile Carbon Change Soil Organic Carbon Mineralization and Microbial Abundance in a Northern Peatland
Authors: Jiang Lei , Ma Xiuyan , Song Yanyu , Gao Siqi , Ren Jiusheng , Zhang Hao , Wang Xianwei
Published: July 2022

Climate warming affects the carbon cycle of northern peatlands through temperature rises and a changing carbon availability. To clarify the effects of elevated temperature and labile carbon addition on SOC mineralization, as well as their microbial driving mechanisms, topsoil (0–10 cm) and subsoil (10–20 cm) were collected from a peatland in the Great Hing’an Mountains and incubated with or without 13C-glucose at 10 °C and 15 °C for 42 days. The results showed that 5 °C warming significantly stimulated SOC mineralization along with NH4+-N and NO3−-N content increases, as well as a decrease in invertase and urease activities. Glucose addition triggered a positive priming effect (PE) in the early stage of the incubation but changed to a negative PE in the late stage of the incubation. Glucose likely regulates carbon dynamics by altering fungi: bacteria, soil invertase, and β-glucodase activities, and MBC, DOC, NH4+-N contents. Glucose addition increased fungal abundance in 0–10 cm at 10 °C and 15 °C, and 10–20 cm at 10 °C, respectively, but significantly decreased fungal abundance in 10–20 cm at 15 °C. Glucose addition decreased bacterial abundance in 0–10 cm at 10 °C but increased bacterial abundance in 10–20 cm soil at 10 °C, and in 0–10 and 10–20 cm soils at 15 °C, respectively. Glucose addition significantly decreased the fungi: bacteria ratio in 0–20 cm soils at 15 °C. In addition, Q10 was significantly positively correlated with the changes in soil DOC, NH4+-N contents, invertase, and β-glucosidase activities, while negatively correlated with fungi: bacteria and urease activities after 5 °C of warming, and glucose addition significantly increased the Q10. Labile carbon may decrease carbon losses in northern peatlands that inhibit warming-induced carbon emission increase, thus partially buffering soil carbon content against change.
Prebiotics, Probiotics, and Postbiotics in the Prevention and Treatment of Anemia
Authors: Zakrzewska Zuzanna , Zawartka Aleksandra , Schab Magdalena , Martyniak Adrian , Skoczeń Szymon , Tomasik Przemysław J. , Wędrychowicz Andrzej
Published: July 2022

Iron deficiency anemia (IDA) is very common and affects approximately 1/3 of the world’s human population. There are strong research data that some probiotics, such as Lactobacillus acidophilus and Bifidobacterium longum improve iron absorption and influence the course of anemia. Furthermore, prebiotics, including galactooligosaccharides (GOS) and fructooligosaccharides (FOS), increase iron bioavailability and decrease its destructive effect on the intestinal microbiota. In addition, multiple postbiotics, which are probiotic metabolites, including vitamins, short-chain fatty acids (SCFA), and tryptophan, are involved in the regulation of intestinal absorption and may influence iron status in humans. This review presents the actual data from research studies on the influence of probiotics, prebiotics, and postbiotics on the prevention and therapy of IDA and the latest findings regarding their mechanisms of action. A comparison of the latest research data and theories regarding the role of pre-, post-, and probiotics and the mechanism of their action in anemias is also presented and discussed.
Organ Involvement in COVID-19: A Molecular Investigation of Autopsied Patients
Authors: Shankar Prem , Singh Jitendra , Joshi Ankur , Malhotra Anvita Gupta , Shrivas Arti , Goel Garima , Gupta Priyal , Yadav Jayanthi , Saigal Saurabh , Singh Sarman , Purwar Shashank
Published: July 2022

Precise reasons for severe manifestation of SARS-CoV-2 remain unanswered, and efforts have been focused on respiratory system management. Demonstration of unequivocal presence of SARS-CoV-2 in vital body organs by cadaver autopsy was the only way to prove multi-organ involvement. Hence, the primary objective of the study was to determine presence of the SARS-CoV-2 in various organs of patients succumbing to SARS-CoV-2 infection. A total of 246 samples from different organs of 21 patients who died due to severe COVID-19 illness were investigated by qRT-PCR, and SARS-CoV-2 was detected in 181 (73.57%) samples and highest positivity of SARS-CoV-2 being (expectedly) found in nasopharynx (90.4%) followed by bilateral lungs (87.30%), peritoneal fluid (80%), pancreas (72.72%), bilateral kidneys (68.42%), liver (65%) and even in brain (47.2%). The deceased patients were categorized to three subgroups based upon the extent of organs in which SARS-CoV-2 was detected by qRT-PCR (high intensity ≥80%, intermediate intensity = 65–80% and low intensity ≤65% organs involvement). It was conclusively established that SARS-CoV-2 has the property of invasion beyond lungs and even crosses the blood–brain barrier, resulting in multi-system disease; this is probably the reason behind cytokine storm, though it is not clear whether organ damage is due to direct injury caused by the virus or result of inflammatory assault. Significant inverse correlation was found between the Ct value of lung samples and number of organs involved, implying that higher viral load in lungs is directly proportionate to involvement of extrapulmonary organs and patients with higher viral load in respiratory secretions should be monitored more closely for any warning signs and the treatment strategies should also address involvement of other organs for better outcome, because lungs, though the primary site of infection, are not the only organ system responsible for pathogenesis of systemic illness.