bluuebunny/crossref_metadata_2025 huggingface dataset:
Reduced Iris Yellow Spot Symptoms through Selection within Onion Breeding Lines
Authors: Kamal Neel , Nourbakhsh Seyed , Cramer Christopher
Published: January 2021

Iris yellow spot (IYS) disease in onion (Allium cepa L.) is caused by onion thrips (Thrips tabaci L.) vectored Iris yellow spot virus (IYSV). The absence of cultivars that are resistant/tolerant to thrips and/or IYS is a challenge for onion bulb and seed production worldwide. To measure selection progress for reduced/delayed IYS symptom expression in onion breeding lines after two selection cycles, selections were performed in 2011 on previously evaluated lines that exhibited a reduced symptom expression after one selection cycle. Selected plants from each line were massed in a cage and the resulted progenies were evaluated in 2013 and 2014 along with their original populations and a susceptible check—’Rumba’. In some comparisons, the selection progress for delayed/reduced IYS symptom expression was observed for some breeding lines. Plants of most selected breeding lines exhibited less disease expression than plants of ‘Rumba’. For some selections, a low disease severity was observed even with a relatively high number of thrips per plant. These results suggest that further improvement might be achievable with additional cycles of selection.
Catastrophic Household Expenditure Associated with Out-of-Pocket Healthcare Payments in Spain
Authors: López-López Samuel , del Pozo-Rubio Raúl , Ortega-Ortega Marta , Escribano-Sotos Francisco
Published: January 2021

Background. The financial effect of households’ out-of-pocket payments (OOP) on access and use of health systems has been extensively studied in the literature, especially in emerging or developing countries. However, it has been the subject of little research in European countries, and is almost nonexistent after the financial crisis of 2008. The aim of the work is to analyze the incidence and intensity of financial catastrophism derived from Spanish households’ out-of-pocket payments associated with health care during the period 2008–2015. Methods. The Household Budget Survey was used and catastrophic measures were estimated, classifying the households into those above the threshold of catastrophe versus below. Three ordered logistic regression models and margins effects were estimated. Results. The results reveal that, in 2008, 4.42% of Spanish households dedicated more than 40% of their income to financing out-of-pocket payments in health, with an average annual gap of EUR 259.84 (DE: EUR 2431.55), which in overall terms amounts to EUR 3939.44 million (0.36% of GDP). Conclusion. The findings of this study reveal the existence of catastrophic households resulting from OOP payments associated with health care in Spain and the need to design financial protection policies against the financial risk derived from facing these types of costs.
Experience and Health-Related Behavior in Times of the Corona Crisis in Germany: An Exploratory Psychological Survey Considering the Identification of Compliance-Enhancing Strategies
Authors: Welter Virginia Deborah Elaine , Welter Naemi Georgina Eliane , Großschedl Jörg
Published: January 2021

Despite the need for enduring preventive behavior in times of the COVID-19 pandemic, several counteracting behavioral reactions can be observed worldwide. Considering the grave consequences resulting from such health-related risk behavior, we carried out an online questionnaire study to identify personal characteristics that frame a motivational sketch of those who refuse to follow the pandemic-related preventive measures. Our results from a sample of N = 570 German participants already indicate obvious changes in relevant variables in the four-week investigation period during the pandemic’s initial phase (25 March to 22 April 2020). Above all, the willingness to take preventive measures decreased, as did the assessment of the pandemic’s severity. The perceived own vulnerability also turned out to be clearly age-dependent and, overall, our sample showed a negative affectivity deviating distinctively from a reference sample. These and other findings allow for identification of sources for public health interventions that can help to increase compliance with required prevention behavior, and thus, counteract COVID-19.
Simulating Land-Use Changes and Predicting Maize Potential Yields in Northeast China for 2050
Authors: Pu Luoman , Yang Jiuchun , Yu Lingxue , Xiong Changsheng , Yan Fengqin , Zhang Yubo , Zhang Shuwen
Published: January 2021

Crop potential yields in cropland are the essential reflection of the utilization of cropland resources. The changes of the quantity, quality, and spatial distribution of cropland will directly affect the crop potential yields, so it is very crucial to simulate future cropland distribution and predict crop potential yields to ensure the future food security. In the present study, the Cellular Automata (CA)-Markov model was employed to simulate land-use changes in Northeast China during 2015–2050. Then, the Global Agro-ecological Zones (GAEZ) model was used to predict maize potential yields in Northeast China in 2050, and the spatio-temporal changes of maize potential yields during 2015–2050 were explored. The results were the following. (1) The woodland and grassland decreased by 5.13 million ha and 1.74 million ha respectively in Northeast China from 2015 to 2050, which were mainly converted into unused land. Most of the dryland was converted to paddy field and built-up land. (2) In 2050, the total maize potential production and average potential yield in Northeast China were 218.09 million tonnes and 6880.59 kg/ha. Thirteen prefecture-level cities had maize potential production of more than 7 million tonnes, and 11 cities had maize potential yields of more than 8000 kg/ha. (3) During 2015–2050, the total maize potential production and average yield decreased by around 23 million tonnes and 700 kg/ha in Northeast China, respectively. (4) The maize potential production increased in 15 cities located in the plain areas over the 35 years. The potential yields increased in only nine cities, which were mainly located in the Sanjiang Plain and the southeastern regions. The results highlight the importance of coping with the future land-use changes actively, maintaining the balance of farmland occupation and compensation, improving the cropland quality, and ensuring food security in Northeast China.
Healthy Dietary Choices and Physical Activity Participation in the Canadian Arctic: Understanding Nunavut Inuit Perspectives on the Barriers and Enablers
Authors: Akande Victor O. , Fawehinmi Timothy O. , Ruiter Robert A.C. , Kremers Stef P.J.
Published: January 2021

Background: Research shows that unhealthy diets and low physical activity are associated with high rates of obesity-linked chronic diseases amongst Nunavut Inuit. To provide contextual insights and deepen our understanding of the factors that underlie these lifestyle choices, we explored the perspectives of Nunavut Inuit on the barriers and enablers of healthy diets and physical activity participation in the community of Iqaluit. Methods: One-on-one semi-structured photo-elicitation interviews were conducted with 16 participants of 18 years and over (10 women, six men). The interviews uncovered the participants’ perspectives on the factors influencing healthy diets and physical activity in their community. Interviews were audio-recorded, transcribed, and uploaded to QSR NVIVO Version 12. Data analysis was achieved using an inductive thematic approach. Results: Six main factors were identified as barriers or enablers to energy balance-related behaviors: cost and affordability of healthy choices; availability of traditional foods and activities; weather conditions and climate change; infrastructure and community resources; social networks of family and friends; and effect of substance use. Conclusion: This study identified six broad areas that should be considered while mapping out interventions to reduce the burden of obesity-related chronic diseases in Nunavut communities.
A Concise Review on Qualitative Research in Dentistry
Authors: Chai Hollis Haotian , Gao Sherry Shiqian , Chen Kitty Jieyi , Duangthip Duangporn , Lo Edward Chin Man , Chu Chun Hung
Published: January 2021

Qualitative research collects non-numerical data that explores human behaviour, attitudes, beliefs and personality characteristics unamendable to quantitative research. The qualitative research questions are open-ended, evolving and non-directional. The study design is flexible and iterative. Purposive sampling is commonly used. The sample size is determined by theoretical saturation. Data collection is generally through in-depth interviews, focus groups and observations. Qualitative research commonly uses thematic analysis and framework analysis, although there is no consensus on analysing qualitative data. The reporting format can be comprehensive, a summary, developmental or selective, subject to the research question. Qualitative research’s potential functions are to describe the form or nature of what exists (contextual), to examine the reasons for or associations between what exists (explanatory), to appraise the effectiveness of what exists (evaluative), and to aid the development of strategies (generative). Qualitative research can be time consuming to conduct because it explores evolving questions; difficult to generalise because it recruits limited participants; and arduous when it comes to making systematic comparisons because responses are subjective. However, qualitative research can provide depth and detail, create openness, simulate people’s individual experiences and avoid pre-judgements. This concise review provides an overview and suggestions for dental researchers when conducting a qualitative study.
The Effectiveness of a Board Game-Based Oral Hygiene Education Program on Oral Hygiene Knowledge and Plaque Index of Adults with Intellectual Disability: A Pilot Study
Authors: Liu Hsiu-Yueh , Chen Ping-Ho , Chen Wun-Jyun , Huang Shan-Shan , Chen Jen-Hao , Yao Ching-Teng
Published: January 2021

An oral hygiene board game was designed as an intervention tool and applied to explore the effectiveness for the oral health related knowledge (OHK) score and plaque index (PI) of adults with intellectual disability (ID). This one-group pre/post-test design study was conducted in a residential long-term care facility for 42 participants. The study had one pre-test (baseline) and three post-tests evaluated in both control and intervention stages, respectively. The participants participated in a 60-min oral hygiene board game twice a week during the intervention stage. Total OHK score and PI of the participants were recorded to determine the effectiveness of intervention. There were no differences in OHK score and PI between the two stages at baseline. The results in intervention stage demonstrated a significant gradual increase and reduction in the OHK score when compared with the control stage. A statistically significant improvement in the OHK score and PI (42.29% and −33.28%, respectively) at the end of intervention between two stages was recorded. This study proved a board game is deemed an effective education method applicable to promote the OHK and skills of ID adults.
Exercise Therapy Teamwork in German Rehabilitation Settings: Results of a National Survey Using Mixed Methods Design
Authors: Wais Judith , Geidl Wolfgang , Rohrbach Nina , Sudeck Gorden , Pfeifer Klaus
Published: January 2021

A key prerequisite for implementing biopsychosocial exercise therapy concepts as parts of multimodal rehabilitation programs is interprofessional teamwork. Based on a nationwide survey of exercise therapy using a mixed methods design, it is of interest to determine to what extent there are links between team-related processes (e.g., interprofessional exchange) and structural features of the exercise therapy departments (e.g., department size) and the individual rating of interprofessional teamwork. The first part of the study involved a questionnaire-based survey, where exercise therapy heads of 1146 rehabilitation facilities were contacted. In the second part of the study, 58 exercise therapy heads held discussions in six focus groups. The results from both parts showed that interprofessional teamwork was rated positively overall. Team meetings were seen as the central platform for exchange. However, particularly in larger facilities, the hierarchical position of medical management and lacking resources were negatively associated with interprofessional exchange. The results affirm empirically that a more binding provision of adequate structural and organizational conditions, such as sufficient time slots for liaising on content, are essential for effective teamwork. This would facilitate and improve the promotion of physical activity in multimodal rehabilitation programs.
The Motivation Journey: A Grounded Theory Study on Female Cancer Survivors’ Experience of a Psychological Intervention for Quality of Life
Authors: Durosini Ilaria , Savioni Lucrezia , Triberti Stefano , Guiddi Paolo , Pravettoni Gabriella
Published: January 2021

Psychological interventions are proposed to cancer survivors to support their quality of life against the emotional trauma of cancer and the side effects of treatment. Psychological interventions often require patient engagement and commitment to activities that could be more or less demanding in terms of lifestyle change (e.g., psychotherapy, sports). Analyzing participant motivations (personal aims, expectations, needs) prior to participation is useful to predict their adherence to the intervention as well as final outcomes. Yet, participant motivations may evolve during the intervention because the intervention experience turns out to be meaningful and positively challenging. The present study aimed to obtain a preliminary understanding of the process of motivation change in female cancer survivors who participated in a sport-based intervention to promote quality of life by employing a grounded theory approach. Data analysis took place alongside data collection and according to the procedure of grounded theory (“open coding”, “axial coding”, and “selective coding”) in order to describe the process of motivation change during women’s participation in psychological intervention for quality of life. On 14 women interviewed, 13 reported changing their motivation to participate during the first months of involvement, mostly changing from individualistic to group-related motivations (i.e., from self-care to friendship with other participants and enriching group membership), and from physical to psychological growth (i.e., pursuing not only physical health but also self-fulfillment). The discussion explains the preliminary aspects of the motivation change process and highlights the importance to monitor motivation dynamics within psychological interventions.
The Prevalence of Abdominal Adiposity among Primary Health Care Physicians in Bahia, Brazil: An Epidemiological Study
Authors: Costa André Luiz Brandão , Merces Magno Conceição das , Santana Amália Ivine Costa , Silva Douglas de Souza e , Pimentel Rodrigo Fernandes Weyll , Figueiredo Pedro Carlos Muniz de , Brandão Tatiana Santos , Coelho Julita Maria Freitas , Almeida Alex Almeida e , Damasceno Kairo Silvestre Meneses , Rossi Thais Regis Aranha , Souza Marcio Costa de , Lua Iracema , Silva Dandara Almeida Reis da , Cerqueira Monique Magnavita Borba da Fonseca , Gomes Antonio Marcos Tosoli , Oliveira Jeane Freitas de , Sousa Anderson Reis de , Santana Thiago da Silva , Servo Maria Lúcia Silva , Marinho Márcia Cristina Graça , Magalhães Lucelia Batista Neves Cunha , Silva Arthur Pinto , Marques Sergio Correa , Wolter Rafael Moura Coelho Pecly , Penna Lucia Helena , França Luiz Carlos Moraes , Peres Ellen Marcia , Couto Pablo Luiz Santos , Andrade Priscila Cristina da Silva Thiengo de , Santos Livia Fajin de Mello dos , Fonseca Ana Victória Gomes , Santos Charles Souza , Gonçalves Lívia Maria da Silva , D’Oliveira Júnior Argemiro
Published: January 2021

Background: Labor activities are demanding for workers and can induce occupational stress. Primary health care (PHC) workers have faced problems that can lead to the development of stress and abdominal obesity. The aim of this study was to estimate the prevalence of abdominal adiposity among primary health care physicians in the metropolitan mesoregion of Salvador, Bahia. Methods: This is a cross-sectional study conducted with physicians from the family health units (FHUs) of the metropolitan mesoregion of Salvador, Bahia, Brazil. The number of FHUs corresponded to 41 teams (52 physicians). Anamnesis was performed and a questionnaire was applied. The clinical examination consisted of measuring waist circumference (WC), blood pressure levels (BP), and body mass index (BMI), as well as examining for acanthosis nigricans. Blood samples were collected for biochemical dosages. The data obtained were analyzed by SPSS version 22.0. Results: The sample included 41 physicians (response rate: 78.8%), of which 18 were women (44.0%). The percentage of overweight participants represented by BMI was 31.7%. The hypertriglyceridemia prevalence was 29.2%. HDL-c was low in 48.7% of the participants. The waist circumference measurement revealed a prevalence of abdominal adiposity of 38.8% (women) and 34.8% (men). Conclusions: Medical professionals in PHC are more susceptible to having higher abdominal adiposity, especially female physicians.
Evaluation of General Practice Pharmacists: Study Protocol to Assess Interprofessional Collaboration and Team Effectiveness
Authors: Sudeshika Thilini , Naunton Mark , Peterson Gregory M. , Deeks Louise S. , Thomas Jackson , Kosari Sam
Published: January 2021

The inclusion of pharmacists into general practices has expanded in Australia. However, there is a paucity of research examining interprofessional collaboration and team effectiveness after including a pharmacist into the general practice team in primary or community care. This is a protocol for a cross-national comparative mixed-methods study to (i) investigate interprofessional collaboration and team effectiveness within the general practice team after employing pharmacists in general practices in the Australian Capital Territory (ACT) and (ii) to compare interprofessional collaboration and team effectiveness of pharmacists in general practice across Australia with international sites. The first objective will be addressed through a multiphase sequential explanatory mixed-method design, using surveys and semi-structured interviews. The study will recruit general practice pharmacists, general practitioners, and other health professionals from eight general practices in the ACT. Quantitative and qualitative results will be merged during interpretation to provide complementary perspectives of interprofessional collaboration. Secondly, a quantitative descriptive design will compare findings on interprofessional collaboration (professional interactions, relationship initiation, exchange characteristics, and commitment to collaboration) and team effectiveness of general practice pharmacists in Australia with international sites from Canada and the United Kingdom. The results of the study will be used to provide recommendations on how to best implement the role of general practice pharmacists across Australia.
The Role of Panx3 in Age-Associated and Injury-Induced Intervertebral Disc Degeneration
Authors: Serjeant Meaghan , Moon Paxton M. , Quinonez Diana , Penuela Silvia , Beier Frank , Séguin Cheryle A.
Published: January 2021

Pannexin 3 (Panx3) is a mechanosensitive, channel-forming glycoprotein implicated in the progression of post-traumatic osteoarthritis. Despite evidence for Panx3 expression in the intervertebral disc (IVD), its function in this cartilaginous joint structure remained unknown. Using Panx3 knockout mice, this study investigated the role of Panx3 in age-associated IVD degeneration and degeneration induced by annulus fibrosus (AF) needle puncture. Loss of Panx3 did not significantly impact the progression of age-associated histopathological IVD degeneration; however, loss of Panx3 was associated with decreased gene expression of Acan, Col1a1, Mmp13 and Runx2 and altered localization of COLX in the IVD at 19 months-of-age. Following IVD injury in the caudal spine, histological analysis of wild-type mice revealed clusters of hypertrophic cells in the AF associated with increased pericellular proteoglycan accumulation, disruptions in lamellar organization and increased lamellar thickness. In Panx3 knockout mice, hypertrophic AF cells were rarely detected and AF structure was largely preserved post-injury. Interestingly, uninjured IVDs adjacent to the site of injury more frequently showed evidence of early nucleus pulposus degeneration in Panx3 knockout mice but remained healthy in wild-type mice. These findings suggest a role for Panx3 in mediating the adaptive cellular responses to altered mechanical stress in the IVD, which may buffer aberrant loads transferred to adjacent motion segments.
Ultrasonic Deposition of Carbon Nanotubes on Polycrystalline Cubic Boron Nitride Composites
Authors: Pacella Manuela , Saremi-Yarahmadi Sina , Lamberti Luciano
Published: January 2021

Polycrystalline cubic boron nitride (PcBN) are super-hard materials with high hardness and excellent abrasive resistance, widely used in cutting tools for precision machining of automotive and aerospace parts; however, their brittle properties make them prone to premature failure. Coatings are often applied to PcBN to extend their range of applicability and durability. Conventional coating methods are limited to the thickness range of a few hundred nanometres, poor adhesion to the substrate, and limited stability under ambient conditions. To further the properties of PcBN composites, in this paper, we explore the use of ultrasonic bonding to apply thick coatings (30–80 μm) on PcBN cutting tools. For the first time, a multi-walled carbon nanotube (MWCNT) powder is preplaced on a PcBN substrate to allow an unconventional coating technique to take place. The effects of ultrasonic bonding parameters on the change of mechanical properties of the coated tools are investigated through scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), micro-hardness analyses, and white light interferometry. The structure of the carbon nanotubes is investigated through transmission electron microscopy (pre coating) and cross-section of the bonded MWCNTs is studied via focused ion beam milling and SEM to evaluate the bonding between the multi-walled nanotubes. Optimum processing windows (i.e., bonding speed, energy, and pressure) are discovered for coating MWCNTs on PcBN. Focus ion beam milling analyses revealed a relationship between consolidation parameters and porosity of MW(pCNT) bonds. The proposed method paves the way for the novel design of functional coatings with attunable properties (i.e., thickness and hardness) and therefore improved productivity in the machining of aerospace and automotive parts.
Transferability of Molecular Potentials for 2D Molybdenum Disulphide
Authors: Maździarz Marcin
Published: January 2021

An ability of different molecular potentials to reproduce the properties of 2D molybdenum disulphide polymorphs is examined. Structural and mechanical properties, as well as phonon dispersion of the 1H, 1T and 1T’ single-layer MoS2 (SL MoS2) phases, were obtained using density functional theory (DFT) and molecular statics calculations (MS) with Stillinger-Weber, REBO, SNAP and ReaxFF interatomic potentials. Quantitative systematic comparison and discussion of the results obtained are reported.
Strive to Reduce Slurry Erosion and Cavitation in Pumps through Flow Modifications, Design Optimization and Some Other Techniques: Long Term Impact on Process Industry
Authors: Noon Adnan Aslam , Jabbar Absaar Ul , Koten Hasan , Kim Man-Hoe , Ahmed Hafiz Waqar , Mueed Umair , Shoukat Ahmad Adnan , Anwar Bilal
Published: January 2021

Centrifugal pumps are being widely used in various industries for moving fluids that carry solids through pipelines where the need of head and flow rate is not high. Slurry erosion and cavitation are an extremely complex and not yet fully understood phenomenon that occur in centrifugal pumps; however, these undesirable phenomena can be reduced to a certain extent. Appropriate design and development of experiments is required to reasonably predict slurry erosion and cavitation. However, CFD methodology complements analytical solutions and experiments whenever testing of equipment has limitations. The current paper highlights the various slurry erosion and cavitation reduction techniques utilized by different researchers. Economic analysis conducted for a case study relevant to centrifugal pump (CP) usage in Pakistan shows that an 8% enhancement in pump efficiency can reduce the life cycle cost to about 17.6%, which could save up to USD 4281 for a single pump annually in Pakistan.
A Highly Sensitive Room Temperature CO2 Gas Sensor Based on SnO2-rGO Hybrid Composite
Authors: Lee Zhi Yan , Hawari Huzein Fahmi bin , Djaswadi Gunawan Witjaksono bin , Kamarudin Kamarulzaman
Published: January 2021

A tin oxide (SnO2) and reduced graphene oxide (rGO) hybrid composite gas sensor for high-performance carbon dioxide (CO2) gas detection at room temperature was studied. Since it can be used independently from a heater, it emerges as a promising candidate for reducing the complexity of device circuitry, packaging size, and fabrication cost; furthermore, it favors integration into portable devices with a low energy density battery. In this study, SnO2-rGO was prepared via an in-situ chemical reduction route. Dedicated material characterization techniques including field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive X-ray (EDX) spectroscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) were conducted. The gas sensor based on the synthesized hybrid composite was successfully tested over a wide range of carbon dioxide concentrations where it exhibited excellent response magnitudes, good linearity, and low detection limit. The synergistic effect can explain the obtained hybrid gas sensor’s prominent sensing properties between SnO2 and rGO that provide excellent charge transport capability and an abundance of sensing sites.
Evaluation of Appropriate Hysteresis Model for Nonlinear Dynamic Analysis of Existing Reinforced Concrete Moment Frames
Authors: Son Joo-Ki , Lee Chang-Hwan
Published: January 2021

Various seismic analysis methods are being used to predict the response of structures to earthquakes. Although nonlinear dynamic analysis (NDA) is considered an ideal method to represent the most realistic behavior of a structure among these various methods, correct results can be derived only when the analysis model is carefully developed by a knowledgeable person. It is particularly important to properly implement the behavior characteristics depending on the reversed cyclic load in the NDA of a building made of reinforced concrete (RC) moment frames. This study evaluated the hysteresis model suitable for NDA of existing RC moment frames, and 45 analysis models were reviewed, in which the pivot, concrete, and Takeda hysteresis models were applied differently to beams and columns. The pivot model was evaluated as the most reliable hysteresis model for each structural member by comparing and analyzing not only the responses of the entire frame but also the responses of column and beam members focusing on energy dissipation. However, this model can have practical limitations in that the parameters associated with the reinforcement detailing and applied loads need to be defined in detail. The analysis model applying Takeda to the beam, which predicted the average response at a reliable level compared to the reference model, was identified as a practical alternative when it is difficult to apply the pivot model to all frame members.
High-Temperature Oxidation Properties and Microstructural Evolution of Nanostructure Fe-Cr-Al ODS Alloys
Authors: Li Zhengyuan , Chen Lijia , Zhang Haoyu , Liu Siyu
Published: January 2021

The oxidation behavior and microstructural evolution of the nanostructure of Fe-Cr-Al oxide dispersion strengthened (ODS) alloys prepared by spark plasma sintering were investigated by high-temperature oxidation experiments in air at 1200 °C for 100 h. The formation of Al2O3 scale was observed by X-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS) line scans. The oxidation rate of Fe-Cr-Al ODS alloys is lower than that of conventional Fe-Cr-Al alloys, and the oxide layer formed on the Fe-Cr-Al alloy appeared loose and cracked, whereas the oxide layer formed on the Fe-Cr-Al ODS alloys was adherent and flat. This is due to the high density of dispersed nano-oxides hindering the diffusion of Al element and the formation of vacancies caused by them. In addition, the nano-oxides could also adhere to the oxide layer. Besides, the microstructure of the Fe-Cr-Al ODS alloy had excellent stability during high-temperature oxidation.
Investigating the Effect of Repeated High Water Pressure on the Compressive and Bond Strength of Concrete with/without Steel Bar
Authors: Muhaimin Ahmad Aki , Adel Mohamed , Nagai Kohei
Published: January 2021

The application of reinforced concrete for permanent and temporary deep ocean structures has recently become more prevalent; however, the static and dynamic effects of high water pressure on concrete remain unexplored. This paper investigates the influence of high water pressure (60 MPa) on four series of concrete cylinders with and without an embedded steel bar under sustained and cyclic loading conditions. The residual compressive strength, bond strength, and associated evolution of surface and internal damage are evaluated after exposing concrete cylinders to a water pressure of 60 MPa. The first series is exposed to sustained water pressure for 7 and 60 days, while the other series is tested under repeated water pressure for 10, 20, 30, 60, and 150 cycles. The results reveal that residual compressive strength falls immediately by 16% within 7 days of sustained high water pressure, but the strength then remains stable up to 60 days. Under repeated high water pressure, residual compressive strength gradually reduces by up to 40% until 60 cycles, after which it remains reasonably stable until 150 cycles as crack propagation is arrested at a certain depth within the concrete cylinders. The bond strength between the steel bar and matrix is observed to decrease considerably under repeated cycles of 60 MPa water pressure up to 26%. The damage gradually propagates at the matrix/steel bar interface under the repeated water pressure, resulting in a reduction in residual pullout capacity.
Analysis of the Morpho-Geometrical Changes of the Root Canal System Produced by TF Adaptive vs. BioRace: A Micro-Computed Tomography Study
Authors: Alsofi Loai , Al Harbi Muhannad , Stauber Martin , Balto Khaled
Published: January 2021

We aimed to analyze the morpho-geometric changes of the root canal system created by two rotary systems (TF Adaptive and BioRace) using micro-CT technology. Two concepts of rotary file system kinematics, continuous rotation and adaptive kinematics, were used in root canal preparation. Twenty mandibular molars (n = 20) were selected with the following criteria: the teeth have mesial roots with a single and continuous isthmus connecting the mesiobuccal and mesiolingual canals (Vertucci’s Type I configuration) and distal roots with independent canals. Teeth were scanned at a resolution of 14 μm. Canals were divided equally into two groups and then enlarged sequentially using the BioRace system and TF Adaptive system according to manufacturer protocol. Co-registered images, before and after preparation, were evaluated for morphometric measurements of canal surface area, volume, structure model index, thickness, straightening, and un-instrumented surface area. Before and after preparation, data were statistically analyzed using a paired sample t-test. After preparation, data were analyzed using an unpaired sample test. The preparation by both systems significantly changed canal surface area, volume, structure model index, and thickness in both systems. There were no significant differences between instrument types with respect to these parameters (p > 0.05). TF Adaptive was associated with less straightening (8% compared with 17% for BioRace in the mesial canal, p > 0.05). Both instrumentation systems produced canal preparations with adequate geometrical changes. BioRace straightened the mesial canals more than TF Adaptive.
Properties of Journal Bearing Materials That Determine Their Wear Resistance on the Example of Aluminum-Based Alloys
Authors: Mironov Alexander , Gershman Iosif , Gershman Eugeniy , Podrabinnik Pavel , Kuznetsova Ekaterina , Peretyagin Pavel , Peretyagin Nikita
Published: January 2021

Potential relations of tribological characteristics of aluminum antifriction alloys with their compositions and mechanical properties were investigated. In this regard, the properties of eight aluminum alloys containing tin from 5.4% to 11% doped with lead, copper, silicon, zinc, magnesium, and titanium were studied. Mechanical properties such as hardness, strength, relative extension, and impact strength were analyzed. Within the tribological tests seizure load and wear of material were evaluated and secondary structures were studied afterwards. The absence of a definitive correlation between tribological behavior and mechanical properties was shown. It was determined that doping tin over 6% is excessive. The seizure load of the alloys increases with the magnesium content. Secondary structures of the alloys with higher wear rates contain one order less magnesium and tin.
Synthesis of Uniformly Sized Bi0.5Sb1.5Te3.0 Nanoparticles via Mechanochemical Process and Wet-Milling for Reduced Thermal Conductivity
Authors: Park Bo-In , Shin Miri , Park Jaeho , Lee Jae-Seung , Lee Seung Yong , Yu Seunggun
Published: January 2021

In this study, Bi0.5Sb1.5Te3.0 (BST) nanoparticles (NPs) with high crystallinities were synthesized via a mechanochemical process (MCP). X-ray diffraction (XRD), and Raman and X-ray photoelectron spectroscopy (XPS) spectra of the BST NPs showed that the Bi, Sb, and Te powders successfully formed BiSbTe phase and transmission electron microscopy (TEM) images, verifying the high crystallinity and smaller size, albeit agglomerated. The as-synthesized BST NPs with agglomerated clusters were ground into smaller sizes of approximately 41.8 nm with uniform distribution through a simple wet-milling process during 7 days. The thermal conduction behaviors of bulk alloys fabricated by spark plasma sintering (SPS) of the BST NPs were studied by comparing those of samples fabricated from as-synthesized BST NPs and a BST ingot. The thermal conductivities (κ) of the BST nanocomposites were significantly reduced by introducing BST NPs with smaller grain sizes and finer distributions in the temperature range from 300 to 500 K. The BST nanocomposites fabricated from wet-milled BST NPs offered ultralow κ values of 0.84 W m−1 K−1 at approximately 398 K.
Accumulative Deformation Characteristics and Microstructure of Saturated Soft Clay under Cross-River Subway Loading
Authors: Yu Jiangang , Sun Miaomiao , He Shaoheng , Huang Xin , Wu Xi , Liu Liyuan
Published: January 2021

The cross-river subway in the Hangzhou Bay area often passes through deep, thick, soft soil at the bottom of the river. At the same time, overlying erosion, siltation, and changes in water levels adversely affect the deformation of the subway, thereby causing hidden dangers to its safe operation. Using two-way dynamic triaxial testing, the effects of cyclic loading of the cross-river subway on the soft clay foundation were investigated for the first time, using simulation methodology as the prime objective of the present study. A strain development curve for the soft clay was obtained as a result. Considering the effects of effective confining pressure (p′) and radial cyclic stress ratio (τr), an explicit model of accumulative strain on soft clay under cyclic loading of the cross-river subway was established. The results showed that the accumulative axial strain (εd) was closely related to p′ and τr. Under certain conditions, as p′ and τr increased, the εd produced by the soil tended to decrease. Furthermore, through non-destructive testing based on nuclear magnetic resonance (NMR), pore distribution and pore size changes in soft clay during cyclic loading were analyzed. It was observed that under the action of the cross-river loading, the large internal soft clay pores were transformed into small pores, which manifested as a significant decrease in the number of large pores and an increase in the proportion of small pores. Lastly, the macroscopic dynamic soil characteristics observed during triaxial testing closely correlated with the microscopic pore size of the soil obtained in the NMR test, which indicated that using pore distribution and pore size changes to describe microscopic changes was a valid method.
Prevalence of Thyroid Autoimmunity in Women with Recurrent Pregnancy Loss
Authors: Godines-Enriquez Myrna Souraye , Miranda-Velásquez Silvia , Enríquez-Pérez María Magdalena , Arce-Sánchez Lidia , Martínez-Cruz Nayeli , Flores-Robles Claudia Montserrat , Aguayo-González Patricia , Morales-Hernández Fela Vanessa , Villarreal-Barranca Alma , Suárez-Rico Blanca Vianey , Montoya-Estrada Araceli , Romo-Yáñez José , Reyes-Muñoz Enrique
Published: January 2021

Background and objectives: Thyroid autoimmunity (TAI) has been associated with a significantly increased risk of miscarriage in women with recurrent pregnancy loss (RPL). The aim of this study was to determine the prevalence of TAI in women with RPL and compare the clinical characteristics of positive and negative TAI women. Materials and Methods: This is a retrospective cross-sectional study; 203 women with RPL were included. Thyroid profile, anti-thyroid peroxidase (TPO-Ab), and anti-thyroglobulin (TG-Ab) antibodies were measured in all participants. Clinical characteristics and causes of RPL were compared between positive and negative TAI. Results: Prevalence of TAI was 14.8%; prevalence of positive TPO-Ab and TG-Ab was 12.3% and 4.9%, respectively. Women with TAI had significantly higher concentrations of thyrotropin (TSH) compared to women without TAI (4.8 ± 3.8 versus 3.1 ± 1.1, p = 0.001). There was no significant difference in age, the number of gestations, miscarriages, state of antiphospholipid antibodies (aPL), or causes of RPL between women that were TAI-positive versus TAI-negative. Prevalence of positive TAI by cause of RPL was: endocrine 7/25 (28%), genetic 1/5 (20%), autoimmune 1/5 (20%), anatomic 8/55 (14.5%), and unexplained cause 13/112 (11.6%). Conclusions: The prevalence of TAI in women with RPL is 14.8%. Women with an endocrine cause have the highest prevalence of TAI.
Central Composite Experiment Design (CCD)-Response Surface Method (RSM) to Optimize the Sintering Process of Ti-6Al-4V Alloy
Authors: Xia Jing , Liu Shaopeng , Zhang Bing , Chen Yungui
Published: January 2021

It is widely acknowledged that the blended elemental (BE) powder metallurgy (PM) Ti6Al4V alloy attracted unusual due to its low cost and comprehensive mechanical properties. However, the high porosity and mediocre mechanical properties of traditional vacuum sintering limited its application. To achieve better mechanical performance, the central composite designs (CCDs) method was employed to analyze the influence of sintering parameters, such as sintering temperature (St), heating rate (Hr), and holding time (Ht). The results indicated that St makes the most significant contribution to compressive strength and sintering density, accounting for 95.5% and 86.54% respectively. In addition, Ht makes the most significant contribution to compression ratio, which accounted for 89.35%. Through the analysis of response surface methodology (RSM), the optimum sintering parameters (St, Ht, Hr) could be considered to be 1300 °C, 148 min and 5 °C/min. In addition, verification experiments were carried out under the optimum conditions, and the experimental results were in good agreement with the predicted values, since the deviation of the predicted and experimental values was less than 4.9%. Therefore, the results of this study could certify the reliability of CCDs method, which would contribute to the development of titanium alloys with low cost and high mechanical properties.
Bifurcation Analysis of a Micro-Machined Gyroscope with Nonlinear Stiffness and Electrostatic Forces
Authors: Zhang Huabiao , Li Xinye , Zhang Lijuan
Published: January 2021

The bifurcation of the periodic response of a micro-machined gyroscope with cubic supporting stiffness and fractional electrostatic forces is investigated. The pull-in phenomenon is analyzed to show that the system can have a stable periodic response when the detecting voltage is kept within a certain range. The method of averaging and the residue theorem are employed to give the averaging equations for the case of primary resonance and 1:1 internal resonance. Transition sets on the driving/detecting voltage plane that divide the parameter plane into 12 persistent regions and the corresponding bifurcation diagrams are obtained via the singularity theory. The results show that multiple solutions of the resonance curves appear with a large driving voltage and a small detecting voltage, which may lead to an uncertain output of the gyroscope. The effects of driving and detecting voltages on mechanical sensitivity and nonlinearity are analyzed for three persistent regions considering the operation requirements of the micro-machined gyroscope. The results indicate that in the region with a small driving voltage, the mechanical sensitivity is much smaller. In the other two regions, the variations in the mechanical sensitivity and nonlinearity are analogous. It is possible that the system has a maximum mechanical sensitivity and minimum nonlinearity for an appropriate range of detecting voltages.
Collective Polarization of Cancer Cells at the Monolayer Boundary
Authors: Guan Liu-Yuan , Lv Jian-Qing , Zhang De-Qing , Li Bo
Published: January 2021

Cell polarization, a process depending on both intracellular and intercellular interactions, is crucial for collective cell migration that commonly emerges in embryonic development, tissue morphogenesis, wound healing and cancer metastasis. Although invasive cancer cells display weak cell–cell interactions, they can invade host tissues through a collective mode. Yet, how cancer cells without stable cell–cell junctions polarize collectively to migrate and invade is not fully understood. Here, using a wound-healing assay, we elucidate the polarization of carcinoma cells at the population level. We show that with loose intercellular connections, the highly polarized leader cells can induce the polarization of following cancer cells and subsequent transmission of polarity information by membrane protrusions, leading to gradient polarization at the monolayer boundary. Unlike the polarization of epithelial monolayer where Rac1/Cdc42 pathway functions primarily, our data show that collective polarization of carcinoma cells is predominantly controlled by Golgi apparatus, a disruption of which results in the destruction of collective polarization over a large scale. We reveal that the Golgi apparatus can sustain membrane protrusion formation, polarized secretion, intracellular trafficking, and F-actin polarization, which contribute to collective cancer cell polarization and its transmission between cells. These findings could advance our understanding of collective cancer invasion in tumors.
Travelling-Wave Dipolophoresis: Levitation and Electrorotation of Janus Nanoparticles
Authors: Miloh Touvia , Nagler Jacob
Published: January 2021

We present a theoretical study of the hydrodynamic and electrokinetic response of both metallic spherical polarized colloids as well as metallodielectic Janus particles, which are subjected to an arbitrary non-uniform ambient electric field (DC or AC forcing). The analysis is based on employing the linearized ‘standard’ model (Poisson–Nernst–Planck formulation) and on the assumptions of a ‘weak’ field and small Debye scale. In particular, we consider cases of linear and helical time-harmonic travelling-wave excitations and provide explicit expressions for the resulting dielectrophoretic and induced-charge electrophoretic forces and moments, exerted on freely suspended particles. The new analytic expressions thus derived for the linear and angular velocities of the initially uncharged polarizable particle are compared against some available solutions. We also analyze the levitation problem (including stability) of metallic and Janus particles placed in a cylindrical (insulating or conducting) pore near a powered electrode.
Expanding 3D Nanoprinting Performance by Blurring the Electron Beam
Authors: Seewald Lukas , Winkler Robert , Kothleitner Gerald , Plank Harald
Published: January 2021

Additive, direct-write manufacturing via a focused electron beam has evolved into a reliable 3D nanoprinting technology in recent years. Aside from low demands on substrate materials and surface morphologies, this technology allows the fabrication of freestanding, 3D architectures with feature sizes down to the sub-20 nm range. While indispensably needed for some concepts (e.g., 3D nano-plasmonics), the final applications can also be limited due to low mechanical rigidity, and thermal- or electric conductivities. To optimize these properties, without changing the overall 3D architecture, a controlled method for tuning individual branch diameters is desirable. Following this motivation, here, we introduce on-purpose beam blurring for controlled upward scaling and study the behavior at different inclination angles. The study reveals a massive boost in growth efficiencies up to a factor of five and the strong delay of unwanted proximal growth. In doing so, this work expands the design flexibility of this technology.
Optimisation of Design and Manufacturing Parameters of 3D Printed Solid Microneedles for Improved Strength, Sharpness, and Drug Delivery
Authors: Economidou Sophia , Pissinato Pere Cristiane , Okereke Michael , Douroumis Dennis
Published: January 2021

3D printing has emerged as a powerful manufacturing technology and has attracted significant attention for the fabrication of microneedle (MN)-mediated transdermal systems. In this work, we describe an optimisation strategy for 3D-printed MNs, ranging from the design to the drug delivery stage. The key relationships between design and manufacturing parameters and quality and performance are systematically explored. The printing and post-printing set parameters were found to influence quality and material mechanical properties, respectively. It was demonstrated that the MN geometry affected piercing behaviour, fracture, and coating morphology. The delivery of insulin in porcine skin by inkjet-coated MNs was shown to be influenced by MN design.