bluuebunny/crossref_metadata_2025 huggingface dataset:
Impacts of Household Coal Combustion on Indoor Ultrafine Particles—A Preliminary Case Study and Implication on Exposure Reduction
Authors: Luo Zhihan , Xing Ran , Huang Wenxuan , Xiong Rui , Qin Lifan , Ren Yuxuan , Li Yaojie , Liu Xinlei , Men Yatai , Jiang Ke , Tian Yanlin , Shen Guofeng
Published: April 2022

Ultrafine particles (UFPs) significantly affect human health and climate. UFPs can be produced largely from the incomplete burning of solid fuels in stoves; however, indoor UFPs are less studied compared to outdoor UFPs, especially in coal-combustion homes. In this study, indoor and outdoor UFP concentrations were measured simultaneously by using a portable instrument, and internal and outdoor source contributions to indoor UFPs were estimated using a statistical approach based on highly temporally resolved data. The total concentrations of indoor UFPs in a rural household with the presence of coal burning were as high as 1.64 × 105 (1.32 × 105–2.09 × 105 as interquartile range) #/cm3, which was nearly one order of magnitude higher than that of outdoor UFPs. Indoor UFPs were unimodal, with the greatest abundance of particles in the size range of 31.6–100 nm. The indoor-to-outdoor ratio of UFPs in a rural household was about 6.4 (2.7–16.0), while it was 0.89 (0.88–0.91) in a home without strong internal sources. A dynamic process illustrated that the particle number concentration increased by ~5 times during the coal ignition period. Indoor coal combustion made up to over 80% of indoor UFPs, while in an urban home without coal combustion sources indoors, the outdoor sources may contribute to nearly 90% of indoor UFPs. A high number concentration and a greater number of finer particles in homes with the presence of coal combustion indicated serious health hazards associated with UFP exposure and the necessity for future controls on indoor UFPs.
Pareidolia in a Built Environment as a Complex Phenomenological Ambiguous Stimuli
Authors: Wang Chen , Yu Liangcheng , Mo Yiyi , Wood Lincoln C. , Goon Carry
Published: April 2022

Pareidolia is a kind of misperception caused by meaningless, ambiguous stimuli perceived with meaning. Pareidolia in a built environment may trigger the emotions of residents, and the most frequently observed pareidolian images are human faces. Through a pilot experiment and an in-depth questionnaire survey, this research aims to compare built environmental pareidolian phenomena at different time points (6 a.m., 12 p.m., 2 a.m.) and to determine people’s sensitivity and reactions towards pareidolia in the built environment. Our findings indicate that the differences in stress level do not influence the sensitivity and reactions towards pareidolia in the built environment; however, age does, and the age of 40 seems to be a watershed. Females are more likely to identify pareidolian faces than males. Smokers, topers, and long-term medicine users are more sensitive to pareidolian images in the built environment. An unexpected finding is that most pareidolian images in built environments are much more easily detected in the early morning and at midnight but remain much less able to be perceived at midday. The results help architects better understand people’s reactions to pareidolia in the built environment, thus allowing them to decide whether to incorporate it appropriately or avoid it consciously in building design.
Trends in HIV Testing and Associated Factors among Adolescent Girls and Young Women in Zimbabwe: Cross-Sectional Analysis of Demographic and Health Survey Data from 2005 to 2015
Authors: Pachena Abgail , Musekiwa Alfred
Published: April 2022

Adolescent girls and young women (AGYW), aged 15–24 years, experience higher HIV incidence compared to their male counterparts, especially in sub-Saharan Africa (SSA), where the HIV burden is highest. This study determined trends in self-reported HIV testing and associated factors among AGYW in Zimbabwe using the Zimbabwe DHS datasets for 2005/6, 2010/11, and 2015. The proportion of adolescents aged 15–19 years who had ever tested for HIV increased from 14.7% in 2005/6 to 26.5% in 2010/11 and 47.9% in 2015. Among young women, aged 20–24 years, the proportion increased from 34.8% in 2005/6 to 68.7% in 2010/11 and 84.8% in 2015. The odds of ever having an HIV test were significantly higher for those with a higher education (adjusted odds ratio [aOR] 12.49, 95% CI: 2.69 to 57.92, p = 0.001), comprehensive HIV knowledge (aOR 1.91, 95% CI: 1.31 to 2.78, p = 0.001), knowledge about mother-to-child transmission (MTCT) (aOR 2.09, 95% CI: 1.55 to 2.82, p < 0.001), non-discriminatory attitudes (aOR 1.60, 95% CI: 1.12 to 2.28, p = 0.010), three or more lifetime sexual partners (aOR 2.0, 95% CI: 1.09 to 3.66, p = 0.025), and a history of pregnancy (aOR 6.08, 95% CI: 4.22 to 8.75, p < 0.001). There is need to scale-up programmes targeting AGYW.
Towards an Integrative Theory of Bullying in Residential Care for Youth
Authors: Sekol Ivana , Farrington David P. , Ireland Jane L.
Published: April 2022

To date, no theory of bullying in residential care for youth has been proposed. By drawing on the results of the existing research on bullying and peer violence in youth residential care and adapting the Multifactor Model of Bullying in Secure Settings (MMBSS), this paper proposes the first integrative theory of bullying in residential care—the Multifactor Model of Bullying in Residential Settings (MMB-RS). The paper first summarises the existing empirical findings on bullying and peer violence in residential care for youth and describes the MMBSS. It then moves on to proposing and describing the MMB-RS. In a nutshell, the MMB-RS assumes that bullying in residential care is shaped by a dynamic interaction between a complex set of individual and contextual factors. The model also takes into account the interaction between bullies and victims, thus explicitly considering the social interactional components of bullying and victimisation and offering possible explanations of the sizable overlap between bullying and victimisation in residential care, including the possible contributions of residential peer cultures. The paper concludes by noting the importance of empirically testing the MMB-RS and proposing a programme of research that may be helpful in testing it.
Madelung’s Disease as an Example of a Metabolic Disease Associated with Alcohol Abuse—Diagnostic Importance of Computed Tomography
Authors: Jaźwiec Przemysław , Pawłowska Maria , Czerwińska Karolina , Poręba Małgorzata , Gać Paweł , Poręba Rafał
Published: April 2022

Madelung’s disease is a rare metabolic disorder characterized by a symmetrical accumulation of nonencapsulated adipose tissue deposits, mainly around the head, neck and shoulders. Fat deposits can grow and put pressure on other organs causing a variety of symptoms, inter alia, dysphagia, breathing difficulties, neck stiffness and headache. Madelung’s disease is often accompanied by other disorders such as diabetes, hypertension, hypothyroidism, or liver disease. In addition to somatic issues, mental health problems may also develop causing social exclusion and depression. Middle-aged men with a history of alcohol abuse are the most commonly affected. Various imaging techniques, including computed tomography (CT), are helpful in stating the diagnosis. This paper presents a case of a 33-year-old man with extensive adipose tissue overgrowth around neck and chest. CT-enhanced scans with multiplanar reconstruction (MPR) and volume rendering technique (VRT) reconstruction are also included.
Hopelessness in Police Officers and Its Association with Depression and Burnout: A Pilot Study
Authors: Civilotti Cristina , Acquadro Maran Daniela , Garbarino Sergio , Magnavita Nicola
Published: April 2022

Hopelessness is a particularly critical condition and a risk factor for suicide. Many studies have reported that this condition is common in some occupations and is associated with high stress that is not properly managed. This study examined the prevalence of hopeless status (HS) in a sample of police officers (POs) and the association of hopelessness with depression, burnout, and suicidality. In total, 127 out of 231 POs participated in the survey; they were assessed with the Beck Hopelessness Scale, the Beck Depression Scale, and the Maslach Burnout Inventory. A total of 26.5% of POs reported hopelessness, and a significant association was found with depression and burnout; in individual cases, these conditions were associated with suicidal thoughts. In a multivariate logistic regression model adjusted for confounding variables, depression, emotional exhaustion, and reduction of personal accomplishment were significantly associated with HP status. Depression (OR = 3.02, 95% CI: 1–9.12) and emotional exhaustion (OR = 1.88, 95% CI: 1.06–3.32) significantly increased the risk of hopelessness, while personal accomplishment (OR = 0.57, 95% CI: 0.32–1) was a protective factor. Hopelessness appears to be a very important factor to consider when assessing POs’ mental health.
Variables Determining Higher Home Care Effectiveness in Patients with Chronic Cardiovascular Disease
Authors: Szlenk-Czyczerska Elżbieta , Guzek Marika , Bielska Dorota Emilia , Ławnik Anna , Polański Piotr , Kurpas Donata
Published: April 2022

The aim of this cross-sectional study was to analyze the variables that influence the effectiveness of home care in patients with chronic cardiovascular disease and their informal caregivers. The study was conducted in 193 patients and their 161 informal caregivers. The study used the WHOQOL-BREF Quality of Life Questionnaire, the health behavior inventory questionnaire (HBI), the Camberwell assessment of need short appraisal schedule (CANSAS) and the hospital anxiety and depression scale–modified (HADS–M) version. Spearman’s rank correlation coefficient test and logistic regression were used for analyses. Analysis of patients revealed an association between home care effectiveness and the following variables (OR per unit): age (OR = 0.98, 95% CI: 0.95–0.99), educational level (OR = 1.45, 95% CI: 1.05–2.02), financial status (OR = 0.43, 95% CI: 0.21–0.83), medication irregularity (OR = 0.25, 95% CI: 0.07–0.72), presence of comorbidities (OR = 6.18, 95% CI: 1.83–23.78), health care services provided by a nurse (OR = 1.25, 95% CI: 1.03–1.64), and number of visits to a cardiology clinic (OR = 1.25, 95% CI: 1.02–1.59). There was no association between care effectiveness and sex (p = 0.28), place of residence (p = 0.757), duration of cardiovascular disease (p = 0.718), number of home visits (p = 0.154), nursing interventions (p = 0.16), and adherence to lifestyle change recommendations (p = 0.539) or proper dietary habits (p = 0.355). A greater chance of improved health care effectiveness was found in patients whose caregivers reported higher social (OR = 1.24, 95% CI: 1.09–1.44), psychological (OR = 1.68, 95% CI: 1.25–2.37), and physical (OR = 1.24, 95% CI: 1.05–1.49) quality of life. Patients with cardiovascular disease who were characterized by lower educational attainment, poorer financial status, fewer visits to cardiology clinics, lower utilization of medical services, poorer self-perception of mental and physical well-being, recent onset of disease symptoms, and irregular use of medications, were much more likely to have poorer health care effectiveness. Patients with cardiovascular disease and their caregivers can be well supported at home as long as the care model is tailored to the specific needs. This includes family care coordination in the health care team, home care, and general practice support.
Association of Salivary IGF and IGF/IGFBP-3 Molar Ratio with Cervical Vertebral Maturation Stages from Pre-Adolescent to Post-Adolescent Transition Period—A Cross-Sectional Exploratory Study
Authors: Almalki Abdullah
Published: April 2022

Background: The relevance of growth determination in orthodontics is driving the search for the most precise and least invasive way of tracking the pubertal growth spurt. Objectives: The aim was to explore whether minimally invasive salivary estimation of biomarkers Insulin-like growth factor (IGF-1) and Insulin-like growth factor binding protein-3 (IGFBP-3) could be used to estimate skeletal maturity with diagnostic accuracy, especially in children and adolescent age groups. Subjects and methods: The cross-sectional study was conducted on 105 participants aged 6–25 years from the out-patient Department of Preventive Dental Science at Majmaah University between the period 2 January 2021 and 12 July 2021. Each subject’s lateral cephalogram radiograph was categorized based on skeletal maturity, and saliva samples were estimated for IGF-1 and IGFBP-3 using the respective ELISA kits. Two-way ANOVA with interaction was applied to examine the main effects due to cervical vertebral maturation staging (CVS), Sex and interaction effect due to CVS, and Sex on study parameters. Karl Pearson’s Product Moment Correlation Coefficient was calculated for finding a significant association between IGF, IGFBP3, and the IGF-1/IGFBP3 molar ratio. Results: Highest mean salivary IGF-1 was observed in the pubertal peak stage, which coincides with cervical vertebral maturity stages 3 and 4 (CVS3 and CVS4) for both males (2.57 ng/mL) and females (1.57 ng/mL) and the lowest mean level of IGF-1 for females (0.85 ng/mL) and males (1.22 ng/mL) was observed during the prepubertal stage. There exists a significant variation in IGF-1 between males and females in the pubertal stage (p < 0.01), but the difference is very narrow in the prepubertal and post-pubertal groups (p > 0.05). There was no significant interaction effect of different skeletal stages and gender on the IGFBP3 and the IGF-1/IGFBP3 molar ratio (p > 0.05), but there exists a significant interaction effect on IGF-1 (p < 0.05). Conclusion: Estimation of the IGF-1 and the IGF-1/IGFBP3 molar ratio in saliva, being a non-invasive biological marker, could serve as an adjunctive tool along with radiographic assessment in estimating growth maturity in the adolescence age group. By initiating orthodontic treatment during the mandibular growth peak in adolescence, a positive outcome is ensured in managing skeletal deformities within the craniofacial complex.
Predictors of Healthcare Professionals’ Work Difficulty Perception during the COVID-19 Pandemic: Study of Work Environment in a Pandemic Hospital
Authors: Emhan Abdurrahim , Elkefi Safa , Asan Onur
Published: April 2022

COVID-19 has dramatically changed the work environment in healthcare, which is creating an additional burden for healthcare professionals. In this study, we investigate the factors that trigger professionals to have negative perceptions of their jobs during the pandemic. A cross-sectional survey is used for this study. The respondents are selected based on convenience random sampling. We use 345 questionaries for the analysis. Respondents are health care professionals (nurses, doctors, midwives, technicians, etc.) working in a pandemic hospital in Turkey. We run a multivariable logistic regression model to analyze the predictors of work difficulty perception. The model is adjusted for the respondents’ demographical characteristics and emotional wellbeing. We found that depression and burnout are significantly correlated with the perception of job difficulty (OR Severe PHQ-9 = 10.8, p = 0.004; OR Severe Burnout = 7.83, p < 0.001). The professionals who are changed from one department to another are also more likely to perceive the job as difficult (OR Department Change = 1.60, p = 0.045). However, the professionals that received sufficient applause from society are more likely to think that they did not face any difficulties doing their job during the pandemic (OR Applause = 0.56, p < 0.016). Anxiety, monetary motivation, religious beliefs, and information availability did not contribute to the perceived difficulty in their jobs. Thus, efforts need to be made to give them more social support and smooth their changes in departments and functions to facilitate their jobs.
How Should We Measure? A Review of Circular Cities Indicators
Authors: Bîrgovan Andreea Loredana , Lakatos Elena Simina , Szilagyi Andrea , Cioca Lucian Ionel , Pacurariu Roxana Lavinia , Ciobanu George , Rada Elena Cristina
Published: April 2022

As the world continues to urbanize, it is necessary to identify and implement new urban development models and strategies in order to meet the challenges of sustainable development. As cities continue to face challenges in becoming fully circular, the need to establish a framework to measure the circular economy in urban areas grows. Many definitions for circular cities have been developed and addressed in recent years, as have numerous indicators. To make the transition to a circular city, we must integrate the findings and develop a general definition and measurement framework. This article aims at outlining a framework for circular cities indicators based on their key characteristics, as well providing directions for fostering circularity at the city level. To accomplish this goal, we conducted a systematic review and analyzed key papers published in the field of circular economy to determine how circular cities are measured. Choosing the right indicators to use for developing, monitoring, and evaluating circular cities is a difficult task for urban policymakers, managers, and planners. This highlights the significance of standardized frameworks for urban indicators. As a result, the authors propose a framework and highlight some key points about circular cities and smart urban metabolism.
A Systematic Review of the Experiences and Support Needs of Informal Caregivers for People Who Have Attempted Suicide or Experienced Suicidal Ideation
Authors: Lavers George , Andriessen Karl , Krysinska Karolina
Published: April 2022

Informal caregivers include family, friends, and significant others who provide important support for people who have attempted suicide or experienced suicidal ideation. Despite the prevalence of suicidal behaviour worldwide, they remain an understudied population. This review aimed to synthesise the literature on the experiences and support needs of informal caregivers of people who have attempted suicide or experienced suicidal ideation. We conducted a systematic review according to PRISMA guidelines. Searches of peer-reviewed literature in Medline, Emcare, Embase, EBM Reviews, and PsycINFO identified 21 studies (4 quantitative and 17 qualitative), published between 1986 and 2021. Informal carers commonly reported symptoms of depression and anxiety, for which they receive little assistance. They also expressed a desire for more involvement and education in the professional care of suicidality. Together, the studies indicated a need to improve the way informal caregiving is managed in professional healthcare settings. This review identified potential avenues for future research, as well as broad areas which require attention in seeking to improve the care of suicidal people and their caregivers.
Attitudes toward the Legalization of Euthanasia or Physician-Assisted Suicide in South Korea: A Cross-Sectional Survey
Authors: Yun Young Ho , Sim Jin-Ah , Choi Yeani , Yoon Hyejeong
Published: April 2022

This study aimed to investigate the general South Korean public attitudes toward the legalization of euthanasia or physician-assisted suicide (EAS) and examine the reasons underpinning these attitudes. From March–April 2021, we conducted a cross-sectional survey of a representative national sample of 1000 South Koreans aged 19 years or older. Three in four participants (76.4%) expressed positive attitudes toward the legalization of EAS. Participants who agreed with this legalization reported “meaninglessness of the rest of life” and “right to a good death” as their main reasons. Participants who disagreed with the legalization of EAS reported “respect for life”, “violation of the right to self-determination”, “risk of abuse or overuse”, and “violation of human rights” as theirs. In the multivariate logistic regression analyses, participants with poor physical status (adjusted odds ratio [aOR]: 1.41, 95%; confidence interval [CI]: 1.02–1.93) or comorbidity (aOR: 1.84, 95%; CI: 1.19–2.83) showed positive attitudes toward the legalization of EAS. In summary, most of the general South Korean population regards the legalization of EAS positively, especially participants with poor physical status or comorbidity.
Risk Factors for Road-Traffic Injuries Associated with E-Bike: Case-Control and Case-Crossover Study
Authors: Zhong Zhaohao , Lin Zeting , Li Liping , Wang Xinjia
Published: April 2022

The Electric Bike (EB) has become an ideal mode of transportation because of its simple operation, convenience, and because it is time saving, economical and environmentally friendly. However, electric bicycle road-traffic injuries (ERTIs) have become a road-traffic safety problem that needs to be solved urgently, bringing a huge burden to public health. In order to provide basic data and a theoretical basis for the prevention and control of ERTIs in Shantou, mixed research combining a case-control study and a case-crossover study was carried out to investigate the cycling behavior characteristics and injury status of EB riders in Shantou city, and to explore the influencing factors of ERTI. The case-control study selected the orthopedic inpatient departments of three general hospitals in Shantou. The case-crossover study was designed to assess the effect of brief exposure on the occurrence of ERTIs, in which each orthopedic inpatient serves as his or her own control. Univariable and multivariable logistic regressions were used to examine the associated factors of ERTIs. In the case-control study, multivariable analysis showed that chasing or playing when cycling, finding the vehicle breakdown but continuing cycling, not wearing the helmet, and retrograde cycling were risk factors of ERTIs. Compared with urban road sections, suburb and township road sections were more likely to result in ERTIs. Astigmatism was the protective factor of ERTI. The case-crossover study showed that answering the phone or making a call and not wearing a helmet while cycling increased the risk of ERTIs. Cycling in the motor-vehicle lane and cycling on the sidewalk were both protective factors. Therefore, the traffic management department should effectively implement the policy about wearing a helmet while cycling, increasing the helmet-wearing rate of EB cyclists, and resolutely eliminate illegal behaviors such as violating traffic lights and using mobile phones while cycling. Mixed lanes were high-incidence road sections of ERTIs. It was suggested that adding people-non-motor-vehicles/motor vehicles diversion and isolation facilities in the future to ensure smooth roads and safety would maximize the social economic and public health benefits of EB.
Spatial-Temporal Variation and Mechanisms Causing Spatial Differentiation of Ecosystem Services in Ecologically Fragile Regions Based on Value Evaluation: A Case Study of Western Jilin, China
Authors: Shang Yi , Wang Dongyan , Liu Shuhan , Li Hong
Published: April 2022

The concept of Ecosystem Service Value (ESV) is indispensable when balancing the need for economic development and ecological protection, because it can clarify the ecological assets and values provided by a region. The study of spatio-temporal variation of ESV in ecologically fragile regions is helpful when attempting to restore regional ecological function. Taking the ecologically fragile area in Western Jilin as an example, this paper analyzes the spatial distribution and spatial-temporal evolution characteristics of the integrated ecosystem service value (IESV) in the study area by constructing an IESV model. The drivers of spatial differentiation of integrated ESV in the study area and the mechanisms controlling the interaction between various factors are examined using the geographical detector technique. The results showed that the areas of high value with integrated ecosystem services in Western Jilin were mainly distributed in protected areas, and that there has been a downward trend in the past 23 years. Moreover, the explanatory ability of NDVI (Normalized Difference Vegetation Index) was strongest of any of the natural factors considered. Among the socio-economic factors, the explanatory power of the human activity index (HAI) was greatest. Additionally, the interaction between natural factors and socio-economic factors exhibits synergistic enhancement, which affects the degree of spatial differentiation of IESV. The spatio-temporal variation in IESV is the result of the joint action between human activities and natural factors. This study can provide a scientific basis for the optimization of ecosystems and the development of ecological security in Western Jilin.
Hydrophobic Effect of Soil Stabilization for a Sustainable Subgrade Soil Improvement
Authors: Ezreig Ali Muftah Abdussalam , Mohamad Ismail Mohd Ashraf , Ehwailat Khaled Ibrahim Azarroug
Published: April 2022

The chemical process of using additives to stabilize soils is to improve soil that lacks strong engineering properties. In particular, the moisture susceptibility of subgrade soil through seasonal rains is still questionable. The presence of water in the construction is the cause of deterioration and premature distress of pavements and their supporting geotechnical structures. In this work, the chemical use of hydrophobic caltite (HC) in various amounts (ranging from 3%, 5%, to 7%) and 5% of cement to enhance laterite soils is investigated. The investigation includes the evaluation of soil properties, such as, unconfined compressive strength (UCS) by curing in air and under water, flexural strength (FS), and California Bearing Ratio (CBR) soaked and unsoaked. The addition of caltite with cement increases the strength characteristics with the UCS values of 2078–2853 kPa during the early curing stages (7th day), and 4688–4876 kPa after 90 days of curing. The added caltite in the cement soil samples shows a reduction index of strength loss underwater with the UCS values of 3196, 3334, and 3751 kPa for caltite cemented soil when compared with cement soil alone. FS results suggest that the inclusion of caltite in cement means that post-peak behavior can be enhanced, reducing the brittleness and increasing the ductility. The successful reaction with soil additives occurred in the curing period of 7 days. In terms of the microstructural analysis, results show that HC with cement reduces the porosity, voids, and cracking of laterite soils. Furthermore, new polymer globules, products from the reaction, appeared on the clay particle surfaces, thereby reducing the water absorption. The addition of hydrophobic-caltite to the soil–cement mixture results in increased strength and reduced water absorption in a soil–cement mix, thus achieving a given strength value.
Evaluation of Tensile Bond Strength between Self-Adhesive Resin Cement and Surface-Pretreated Zirconia
Authors: Kim Mijoo , Kim Reuben H. , Lee Samuel C. , Lee Thomas K. , Hayashi Marc , Yu Bo , Jo Deuk-Won
Published: April 2022

The tensile bond strength between zirconia subjected to different surface-pretreatment methods and methacryloyloxydecyl-dihydrogen-phosphate (MDP)-containing self-adhesive resin cement was evaluated herein. Eighty-eight cylindrical zirconia specimens were randomly divided into the following four groups based on the pretreatment method: (1) no treatment, (2) air abrasion, (3) HNO3/HF etching, and (4) zirconia-nanoparticle coating. The tensile bond strength of the zirconia–resin-cement complexes was investigated. One-way ANOVA and post hoc tests were performed at a 95% significance level, and the Weibull modulus was calculated. Fracture patterns were visualized by SEM. The surface roughness of the specimens without resin bonding was evaluated by AFM. The tensile bond strength of the specimens decreased as follows: Groups 3 > 4 > 2 > 1 (28.2 ± 6.6, 26.1 ± 5.7, 16.6 ± 3.3, and 13.9 ± 3.0 MPa, respectively). Groups 3 and 4 had significantly higher tensile bond strengths (p < 0.05) and lower fracture probabilities than those of Groups 1 and 2. They also showed both mixed failure and resin-cement cohesive failure, whereas Groups 1 and 2 showed mixed failure exclusively. The zirconia–resin tensile bond was stronger after HNO3/HF etching or ZrO2-nanoparticle coating than after air abrasion or no treatment. The estimated surface roughness decreased as follows: Groups 3 > 4 > 2 > 1. The combination of zirconia pretreated with HNO3/HF etching or ZrO2-nanoparticle coating and an MDP-containing self-adhesive resin cement can increase the clinical longevity of zirconia restorations by preventing their decementation.
Evaluation of Strength Properties of Sand Stabilized with Wood Fly Ash (WFA) and Cement
Authors: Dimter Sanja , Zagvozda Martina , Tonc Tea , Šimun Miroslav
Published: April 2022

The article describes the laboratory evaluation of mixtures of sand modified with wood fly ash (WFA) and additionally stabilized with different amounts of cement. Laboratory research includes determining the California Bearing Ratio (CBR), compressive and indirect tensile strengths of the mixtures, and the resistance of mixtures to freezing/thawing cycles. The aim of the research is to determine if WFA, an alternative material, can improve sand bearing capacity and contribute to strength development while reducing necessary cement amounts and satisfying the technical regulation for use in pavement base courses. The test results obtained show that WFA has a considerable stabilization effect on the sand mixture and improves its load bearing capacity. By adding a small quantity of the cement, the hydraulic reaction in the stabilized mixture is more intense and results in greater strengths and an improved resistance to freezing. The test results show that, by replacement of part of the sand with WFA (in the quantity of 30%), greater strengths can be achieved in relation to the mixture of only sand and cement. Additionally, the content of cement necessary for the stabilization of sand (usually 8–12%) is considerably reduced, which enables cost savings in the construction of pavement structures.
Experimental Study on the Shear Strength of Reinforced Concrete Beams with Various Integrated Shear Reinforcements
Authors: Yoo Mooyoung
Published: April 2022

The purpose of this study was to evaluate the shear performance of concrete beams with integrated shear reinforcements made of steel plates and rebar bent in an N shape (N-type rebar), and to evaluate the applicability of the current relevant design standards. For this purpose, four concrete beam specimens were manufactured. Four-point loading tests were performed with all the specimens. The experiments confirmed that both types of shear reinforcements had a shear-reinforcing effect (an about 60% increase in shear strength), but the N-type rebar did not exceed the nominal shear strength, probably because the rebar did not yield sufficiently. A sufficient number of steel-plate-type shear reinforcements yielded in the shear crack. When evaluating the shear performance of a new shear reinforcement, it is necessary to calculate the design strength by actually reflecting whether the shear reinforcements’ yields are due to the angle of the diagonal crack. Calculating the shear contribution based on the strain of the shear reinforcements and comparing this shear strength with those five design standards, the shear strength of the shear reinforcements were evaluated conservatively. It is considered that there will be no problem in structural safety even if the shear design is carried out according to the current design standards.
Design and Characterization of a Rolling-Contact Involute Joint and Its Applications in Finger Exoskeletons
Authors: Liang Renghao , Xu Guanghua , Zhang Qiuxiang , Jiang Kaiyuan , Li Min , He Bo
Published: April 2022

The hand exoskeleton has been widely studied in the fields of hand rehabilitation and grasping assistance tasks. Current hand exoskeletons face challenges in combining a user-friendly design with a lightweight structure and accurate modeling of hand motion. In this study, we developed a finger exoskeleton with a rolling contact involute joint. Specific implementation methods were investigated, including an analysis of the mechanical characteristics of the involute joint model, the formula derivation of the joint parameter optimization algorithm, and the design process for a finger exoskeleton with an involute joint. Experiments were conducted using a finger exoskeleton prototype to evaluate the output trajectory and grasping force of the finger exoskeleton. An EMG-controlled hand exoskeleton was developed to verify the wearability and functionality of the glove. The experimental results show that the proposed involute joint can provide sufficient fingertip force (10N) while forming a lightweight exoskeleton to assist users with functional hand rehabilitation and grasping activities.
Study on the Static Characteristics of a Pre-Pressure Single-Action Membrane-Type Restrictor Used in a Single Oil Pad
Authors: Lu Feng , Wang Zhenzhong , Lei Pengli , Chen Yi
Published: April 2022

In order to further improve the static stiffness of the hydrostatic bearing with the membrane-type restrictor, in this study, a static characteristics model of the pre-pressure single-action membrane-type restrictor (PSMR) is derived, and the criteria for achieving the optimum stiffness of the restrictor are summarized. A PSMR design method following the criteria of optimal stiffness is proposed. Then, the effect of design parameters on the performance of the restrictor is accurately evaluated by numerical simulation and orthogonal experiment with the grinder oil pad, as an example. Finally, the performance of the PSMR is compared with that of the traditional restrictors, and the main source of design error of the membrane-type restrictor is discussed. The results show that the effect of the design error of the membrane structure on the performance of the restrictor is reduced to some extent by the parallel oil circuit of the PSMR. In addition, the membrane-type restrictor designed according to the method of this paper theoretically has better static stiffness than the single-action membrane-type restrictor without pre-pressure, with an average improvement of about 14.14%.
Modeling Physical Interaction and Understanding Peer Group Learning Dynamics: Graph Analytics Approach Perspective
Authors: Abal Abas Zuraida , Norizan Mohd Natashah , Zainal Abidin Zaheera , Abdul Rahman Ahmad Fadzli Nizam , Rahmalan Hidayah , Ahmed Tharbe Ida Hartina , Wan Fakhruddin Wan Farah Wani , Mohd Zaki Nurul Hafizah , Ahmad Sobri Sharizal
Published: April 2022

Physical interaction in peer learning has been proven to improve students’ learning processes, which is pertinent in facilitating a fulfilling learning experience in learning theory. However, observation and interviews are often used to investigate peer group learning dynamics from a qualitative perspective. Hence, more data-driven analysis needs to be performed to investigate the physical interaction in peer learning. This paper complements existing works by proposing a framework for exploring students’ physical interaction in peer learning based on the graph analytics modeling approach focusing on both centrality and community detection, as well as visualization of the graph model for more than 50 students taking part in group discussions. The experiment was conducted during a mathematics tutorial class. The physical interactions among students were captured through an online Google form and represented in a graph model. Once the model and graph visualization were developed, findings from centrality analysis and community detection were conducted to identify peer leaders who can facilitate and teach their peers. Based on the results, it was found that five groups were formed during the physical interaction throughout the peer learning process, with at least one student showing the potential to become a peer leader in each group. This paper also highlights the potential of the graph analytics approach to explore peer learning group dynamics and interaction patterns among students to maximize their teaching and learning experience.
Hermite–Hadamard-Type Inequalities and Two-Point Quadrature Formula
Authors: Barić Josipa
Published: April 2022

As convexity plays an important role in many aspects of mathematical programming, e.g., for obtaining sufficient optimality conditions and in duality theorems, and one of the most important inequalities for convex functions is the Hermite–Hadamard inequality, the importance of this paper lies in providing some new improvements for convex functions and new directions in studying new variants of the Hermite–Hadamard inequality. The first part of the article includes some known concepts regarding convex functions and related inequalities. In the second part of the study, a derivation of the Hermite–Hadamard inequality for convex functions of higher order is given, emphasizing the purpose and importance of some quadrature formulas. In the third section, the applications of the main results are presented by obtaining Hermite–Hadamard-type estimates for various classical quadrature formulas such as the Gauss–Legendre two-point quadrature formula and the Gauss–Chebyshev two-point quadrature formulas of the first and second kind.
Pursuit Differential Game with Slow Pursuers on the 1-Skeleton Graph of the Icosahedron
Authors: Ibragimov Gafurjan , Holboyev Azamat , Ibaydullaev Tolanbay , Pansera Bruno Antonio
Published: April 2022

A differential game of m, 3≤m≤6, pursuers and one evader is studied on an icosahedron in R3. All the players move only along the 1-skeleton graph of the icosahedron when the maximal speeds of the pursuers are less than the speed of the evader. Pursuit is said to be completed if the state of a pursuer coincides with the state of evader at some time. We give a sufficient condition of the completion of pursuit in the game.
Vitamin D3 Serum Levels in Periodontitis Patients: A Case–Control Study
Authors: Olszewska-Czyz Iwona , Firkova Elena
Published: April 2022

Background: Periodontitis is a multifactorial disease characterized by bacterial-dysbiosis-associated, host-mediated inflammation, which results in the loss of the tooth-supporting tissues. Vitamin D3 plays an important role in the tissue homeostasis and its deficiency might have a negative effect on the periodontitis progression and treatment outcomes. Objectives: The aim of the study was to evaluate the vitamin D3 serum levels among patients with periodontitis and healthy subjects. Materials and Methods: A total of 100 generally healthy adult participants (50 diagnosed with periodontitis, 50 with healthy periodontium) were enrolled in the study. The periodontal clinical parameters were measured, radiographs were performed and the 25-hydroxy vitamin D (25(OH)D) test was used to assess vitamin D3 levels. Results: Vitamin D3 levels were found to be statistically significantly lower among periodontitis patients (31.34; SD = 5.62) compared with healthy controls (39.64; SD = 8.77). Vitamin D3 deficiency was corresponding to the stage and grade of the disease as well as the clinical attachment and bone loss. Conclusion: Adequate monitoring of the vitamin D3 serum levels and supplementation could be of benefit in periodontitis treatment.
Graphene Oxide Modified Polyamide 66 Ultrafiltration Membranes with Enhanced Anti-Fouling Performance
Authors: Yan Jiangyi , Nie Lihong , Li Guiliang , Zhu Yuanlu , Gao Ming , Wu Ruili , Wang Beifu
Published: April 2022

Improving the contamination resistance of membranes is one of the most effective ways to address the short service life of membranes. While preparing the membrane system structure, doping nanoparticles into the polymer matrix is beneficial to the preparation of high-performance membranes. To develop a new structure for membrane contamination protection, in this study, a novel asymmetric polyamide 66 composite ultrafiltration (UF) membrane was fabricated by incorporating different masses (ranging from zero to 0.5 wt.%) of graphene oxide (GO) into the polyamide 66 microporous substrate, using formic acid and propylene carbonate as solvents. The effects of GO doping on the morphology, microporous structure and surface of ultrafiltration membranes were investigated by atomic force microscopy (AFM), scanning electron microscopy (SEM), integrated thermal analysis (DSC) and contact angle (CA). In addition, pure water flux, bovine serum albumin (BSA) rejection and contamination resistance were measured to evaluate the filtration performance of different membranes. The overall performance of all the modified membranes was improved compared to pure membranes. The results of contact angle and permeation experiments showed that the addition of GO improved the hydrophilicity of the membrane, but reduced the permeability of the membrane. The minimum flux was only 3.5 L/m2·h, but the rejection rate was 92.5%. Most noteworthy was the fact that GO further enhanced the anti-pollution performance of the membranes and achieved a remarkable performance of 91.32% when the GO content was 0.5 wt.%, which was 1.36 times higher than that of the pure membrane. Therefore, optimal performance was achieved. Furthermore, the UF membrane made of composite substrate offers a promising solution for the development of long-life ultrafiltration membranes with better stability, high-cost efficiency and adequate chemical durability.
Investigations on 2Cr13 Stainless Valves after Dry-Type Laser Degumming
Authors: Li Guang , Li Kai , Zhang Lu , Liang Chen , Wang Chen , Li Benhai , Wang Junlong , Wang Xiaohua , Lei Mingwei , Wei Zhipeng
Published: April 2022

The disabled glue on valve surfaces is known to reduce aircraft durability and performance. In this paper, glue contaminants were removed from 2Cr13 stainless valves by dry-type laser processing with a cold air gun and compared with the chemical soaking method. The laser-processed surface was examined by white-light interferometer, scanning electron microscopy, energy dispersive spectroscopy, X-ray diffractometer, hardness tester, and metallographic microscopy. The substrate surface became a little smoother but also had deeper dips due to laser thermal melting. After laser degumming, the new constituent was found in the laser-irradiated region and analyzed as FeCr0.29Ni0.16C0.06, since the ratio of chemical compositions changed. Based on our simulation and experiments, the temperature of the workpiece was effectively controlled by the cold air gun, and its physical properties, including hardness and metallographic structure, were hardly changed. It was shown that laser degumming provides an alternative method for metal valve cleaning.
Conductance-Aware Quantization Based on Minimum Error Substitution for Non-Linear-Conductance-State Tolerance in Neural Computing Systems
Authors: Huang Chenglong , Xu Nuo , Wang Wenqing , Hu Yihong , Fang Liang
Published: April 2022

Emerging resistive random-access memory (ReRAM) has demonstrated great potential in the achievement of the in-memory computing paradigm to overcome the well-known “memory wall” in current von Neumann architecture. The ReRAM crossbar array (RCA) is a promising circuit structure to accelerate the vital multiplication-and-accumulation (MAC) operations in deep neural networks (DNN). However, due to the nonlinear distribution of conductance levels in ReRAM, a large deviation exists in the mapping process when the trained weights that are quantized by linear relationships are directly mapped to the nonlinear conductance values from the realistic ReRAM device. This deviation degrades the inference accuracy of the RCA-based DNN. In this paper, we propose a minimum error substitution based on a conductance-aware quantization method to eliminate the deviation in the mapping process from the weights to the actual conductance values. The method is suitable for multiple ReRAM devices with different non-linear conductance distribution and is also immune to the device variation. The simulation results on LeNet5, AlexNet and VGG16 demonstrate that this method can vastly rescue the accuracy degradation from the non-linear resistance distribution of ReRAM devices compared to the linear quantization method.
Characterization of High-Risk HPV/EBV Co-Presence in Pre-Malignant Cervical Lesions and Squamous Cell Carcinomas
Authors: Blanco Rancés , Carrillo-Beltrán Diego , Muñoz Juan P. , Osorio Julio C. , Tapia Julio C. , Burzio Verónica A. , Gallegos Iván , Calaf Gloria M. , Chabay Paola , Aguayo Francisco
Published: April 2022

High-risk human papillomaviruses (HR-HPVs) are the etiological agents of cervical cancer. However, a low proportion of HR-HPV-infected women finally develop this cancer, which suggests the involvement of additional cofactors. Epstein–Barr virus (EBV) has been detected in cervical squamous cell carcinomas (SCCs) as well as in low- (LSIL) and high-grade (HSIL) squamous intraepithelial lesions, although its role is unknown. In this study, we characterized HR-HPV/EBV co-presence and viral gene expression in LSIL (n = 22), HSIL (n = 52), and SCC (n = 19) from Chilean women. Additionally, phenotypic changes were evaluated in cervical cancer cells ectopically expressing BamHI-A Rightward Frame 1 (BARF1). BARF1 is a lytic gene also expressed in EBV-positive epithelial tumors during the EBV latency program. HPV was detected in 6/22 (27.3%) LSIL, 38/52 (73.1%) HSIL, and 15/19 (78.9%) SCC cases (p < 0.001). On the other hand, EBV was detected in 16/22 (72.7%) LSIL, 27/52 (51.9%) HSIL, and 13/19 (68.4%) SCC cases (p = 0.177). HR-HPV/EBV co-presence was detected in 3/22 (13.6%) LSIL, 17/52 (32.7%) HSIL, and 11/19 (57.9%) SCC cases (p = 0.020). Additionally, BARF1 transcripts were detected in 37/55 (67.3%) of EBV positive cases and in 19/30 (63.3%) of HR-HPV/EBV positive cases. Increased proliferation, migration, and epithelial-mesenchymal transition (EMT) was observed in cervical cancer cells expressing BARF1. Thus, both EBV and BARF1 transcripts are detected in low- and high-grade cervical lesions as well as in cervical carcinomas. In addition, BARF1 can modulate the tumor behavior in cervical cancer cells, suggesting a role in increasing tumor aggressiveness.
Investigation of the Flotation Separation of Scheelite from Fluorite with a Novel Chelating Agent: Pentasodium Diethylenetriaminepentaacetate
Authors: Zhang Chenhu , Wu Haijun , Sun Wei , Hu Yuehua , Wang Chengyong , Zhu Shan , Chen Peng
Published: April 2022

The recovery of scheelite from calcium-bearing carbonate ores by foam flotation is challenging due to its low separation efficiency. This study investigated the effect of pentasodium diethylenetriaminepentaacetate (PD) on the surface properties of scheelite and fluorite. For this purpose, we performed micro-flotation tests and carried out zeta potential measurements, as well as Fourier transform infrared (FT-IR) and X-ray photoelectron (XPS) spectroscopic measurements, in order to analyze the surface properties of these minerals. The addition of PD as a novel depressor significantly improved the effect of fluorite and sodium oleate (NaOl) on the flotation-based scheelite recovery and separation from fluorite. PD was spontaneously adsorbed onto fluorite through electrostatic and chemical adsorption. By contrast, PD did not appear on the scheelite because of the reaction conditions, surface site, and steric hindrance. X-ray photoelectron spectroscopy measurements and a solution chemistry analysis were used for the determination of the PD-selective adsorption mechanism and key factors derived from multi-layer adsorption onto fluorite, which completely hindered that of NaOl.