bluuebunny/crossref_metadata_2025 huggingface dataset:
A Marketing Approach to a Psychological Problem: Problematic Smartphone Use on Adolescents
Authors: Ertemel Adnan Veysel , Ari Ela
Published: April 2020

Background: Smartphones have become an indispensable part of the daily lives of adolescents in the 21st century, which is characterized by a highly digitized modern world. Besides their many advantages, smartphones might pave the way to compulsive usage and addictive experiences. To remedy this problem, this study proposes an authentic approach which integrates consumer behavior theories and techniques such as unhook and gamification. An education program has been designed based on these approaches to decrease the problematic smartphone use. Method: The participants of the education program consisted of 305 students (48.2% girls and 51.8% boys) with a mean age of 14.57 (SD = 0.74). The Demographic Form and Smartphone Addiction Scale for Adolescents (SASA) were conducted before the education program and three weeks after the education. Results: The results of the paired sample t-test analysis before and after the education program revealed that the SASA total scores decreased significantly (p < 0.01). There are significant differences in terms of gender, mothers’ education and class levels. Conclusion: This research emphasizes the role of an interdisciplinary approach to the addiction problem. The content used in the education program includes strategies that originally aimed at increasing consumption. The effectiveness of the program can be enhanced further in the future along with self-regulatory additions.
Spatial Orientation Skill Performance with a Workshop Based on Green Infrastructure in Cities
Authors: Carbonell-Carrera Carlos , Saorin Jose , Melián-Díaz Dámari , Hess-Medler Stephany
Published: April 2020

Better training of spatial skills of green infrastructure managers will contribute to better planning practices in this field. The professionals using geo-spatial technologies in sustainable city planning require, in their curriculum, specific training focused towards the acquisition of spatial skills. Using maps and geo-spatial technologies, spatial orientation skill is needed. In this research, a workshop based on a green infrastructure has been carried out. A specific teaching strategy for the improvement of spatial orientation skill has been performed. In the workshop, 3D technologies of graphic representation of an urban environment were used such as Cad Mapper, Sketch Up Make 2017 and Google Street View. Thirty-two students (22 treatment group, 10 control group) of agronomic engineering participated. The impact on spatial orientation skill was measured with the Perspective Taking-Spatial Orientation test, through pre- and post-tests. No gender differences were found. The Treatment Group obtained a significant increase of 19.27% in their spatial orientation skill. Participants of the Control group did not significantly increase their spatial orientation skill (3.21%). Specific teaching strategies such as those performed in this research can be effective for the training and development of spatial orientation skill, needed for geospatial planning in the field of Green Infrastructures.
Site Selection of Digital Signage in Beijing: A Combination of Machine Learning and an Empirical Approach
Authors: Wang Yuxue , Li Su , Zhang Xun , Jiang Dong , Hao Mengmeng , Zhou Rui
Published: April 2020

With the extensive use of digital signage, precise site selection is an urgent issue for digital signage enterprises and management agencies. This research aims to provide an accurate digital signage site-selection model that integrates the spatial characteristics of geographical location and multisource factor data and combines empirical location models with machine learning methods to recommend locations for digital signage. The outdoor commercial digital signage within the Sixth Ring Road area in Beijing was selected as an example and was combined with population census, average house prices, social network check-in data, the centrality of traffic networks, and point of interest (POI) facilities data as research data. The data were divided into 100–1000 m grids for digital signage site-selection modelling. The empirical approach of the improved Huff model was used to calculate the spatial accessibility of digital signage, and machine learning approaches such as back propagation neural network (BP neural networks) were used to calculate the potential location of digital signage. The site of digital signage to be deployed was obtained by overlay analysis. The result shows that the proposed method has a higher true positive rate and a lower false positive rate than the other three site selection models, which indicates that this method has higher accuracy for site selection. The site results show that areas suitable for digital signage are mainly distributed in Sanlitun, Wangfujing, Financial Street, Beijing West Railway Station, and along the main road network within the Sixth Ring Road. The research provides a reference for integrating geographical features and content data into the site-selection algorithm. It can effectively improve the accuracy and scientific nature of digital signage layouts and the efficiency of digital signage to a certain extent.
Peptidylarginine Deiminase of Porphyromonas gingivalis Modulates the Interactions between Candida albicans Biofilm and Human Plasminogen and High-Molecular-Mass Kininogen
Authors: Karkowska-Kuleta Justyna , Surowiec Magdalena , Gogol Mariusz , Koziel Joanna , Potempa Barbara , Potempa Jan , Kozik Andrzej , Rapala-Kozik Maria
Published: April 2020

Microorganisms that create mixed-species biofilms in the human oral cavity include, among others, the opportunistic fungus Candida albicans and the key bacterial pathogen in periodontitis, Porphyromonas gingivalis. Both species use arsenals of virulence factors to invade the host organism and evade its immune system including peptidylarginine deiminase that citrullinates microbial and host proteins, altering their function. We assessed the effects of this modification on the interactions between the C. albicans cell surface and human plasminogen and kininogen, key components of plasma proteolytic cascades related to the maintenance of hemostasis and innate immunity. Mass spectrometry was used to identify protein citrullination, and microplate tests to quantify the binding of modified plasminogen and kininogen to C. albicans cells. Competitive radioreceptor assays tested the affinity of citrullinated kinins to their specific cellular receptors. The citrullination of surface-exposed fungal proteins reduced the level of unmodified plasminogen binding but did not affect unmodified kininogen binding. However, the modification of human proteins did not disrupt their adsorption to the unmodified fungal cells. In contrast, the citrullination of kinins exerted a significant impact on their interactions with cellular receptors reducing their affinity and thus affecting the role of kinin peptides in the development of inflammation.
Male sterile 305 Mutation Leads the Misregulation of Anther Cuticle Formation by Disrupting Lipid Metabolism in Maize
Authors: Shi Haichun , Yu Yang , Gu Ronghuan , Feng Chenxi , Fu Yu , Yu Xuejie , Yuan Jichao , Sun Qun , Ke Yongpei
Published: April 2020

The anther cuticle, which is mainly composed of lipid polymers, functions as physical barriers to protect genetic material intact; however, the mechanism of lipid biosynthesis in maize (Zea mays. L.) anther remains unclear. Herein, we report a male sterile mutant, male sterile 305 (ms305), in maize. It was shown that the mutant displayed a defective anther tapetum development and premature microspore degradation. Three pathways that are associated with the development of male sterile, including phenylpropanoid biosynthesis, biosynthesis of secondary metabolites, as well as cutin, suberine, and wax biosynthesis, were identified by transcriptome analysis. Gas chromatography-mass spectrometry disclosed that the content of cutin in ms305 anther was significantly lower than that of fertile siblings during the abortion stage, so did the total fatty acids, which indicated that ms305 mutation might lead to blocked synthesis of cutin and fatty acids in anther. Lipidome analysis uncovered that the content of phosphatidylcholine, phosphatidylserine, diacylglycerol, monogalactosyldiacylglycerol, and digalactosyldiacylglycerol in ms305 anther was significantly lower when compared with its fertile siblings, which suggested that ms305 mutation disrupted lipid synthesis. In conclusion, our findings indicated that ms305 might affect anther cuticle and microspore development by regulating the temporal progression of the lipidome in maize.
Early pH Changes in Musculoskeletal Tissues upon Injury—Aerobic Catabolic Pathway Activity Linked to Inter-Individual Differences in Local pH
Authors: Berkmann Julia C. , Herrera Martin Aaron X. , Ellinghaus Agnes , Schlundt Claudia , Schell Hanna , Lippens Evi , Duda Georg N. , Tsitsilonis Serafeim , Schmidt-Bleek Katharina
Published: April 2020

Local pH is stated to acidify after bone fracture. However, the time course and degree of acidification remain unknown. Whether the acidification pattern within a fracture hematoma is applicable to adjacent muscle hematoma or is exclusive to this regenerative tissue has not been studied to date. Thus, in this study, we aimed to unravel the extent and pattern of acidification in vivo during the early phase post musculoskeletal injury. Local pH changes after fracture and muscle trauma were measured simultaneously in two pre-clinical animal models (sheep/rats) immediately after and up to 48 h post injury. The rat fracture hematoma was further analyzed histologically and metabolomically. In vivo pH measurements in bone and muscle hematoma revealed a local acidification in both animal models, yielding mean pH values in rats of 6.69 and 6.89, with pronounced intra- and inter-individual differences. The metabolomic analysis of the hematomas indicated a link between reduction in tricarboxylic acid cycle activity and pH, thus, metabolic activity within the injured tissues could be causative for the different pH values. The significant acidification within the early musculoskeletal hematoma could enable the employment of the pH for novel, sought-after treatments that allow for spatially and temporally controlled drug release.
Protective Effects of Recombinant Human Soluble Thrombomodulin on Lipopolysaccharide-Induced Acute Kidney Injury
Authors: Nozaki Yuji , Ri Jinhai , Sakai Kenji , Niki Kaoru , Funauchi Masanori , Matsumura Itaru
Published: April 2020

Thrombomodulin (TM) is a single transmembrane, multidomain glycoprotein receptor for thrombin, and is best known for its role as a cofactor in a clinically important natural anticoagulant pathway. In addition to its anticoagulant function, TM has well-defined anti-inflammatory properties. Soluble TM levels increase significantly in the plasma of septic patients; however, the possible involvement of recombinant human soluble TM (rTM) transduction in the pathogenesis of lipopolysaccharide (LPS)-induced nephrotoxicity, including acute kidney injury (AKI), has remained unclear. Mice were injected intraperitoneally with 15 mg/kg LPS. rTM (3 mg/kg) or saline was administered to the animals before the 3 and 24 h LPS-injection. At 24 and 48 h, blood urea nitrogen, the inflammatory cytokines in sera and kidney, and histological findings were assessed. Cell activation and apoptosis signal was assessed by Western blot analysis. In this study using a mouse model of LPS-induced AKI, we found that rTM attenuated renal damage by reducing both cytokine and cell activation and apoptosis signals with the accumulation of CD4+ T-cells, CD11c+ cells, and F4/80+ cells via phospho c-Jun activations and Bax expression. These findings suggest that the mechanism underlying these effects of TM may be mediated by a reduction in inflammatory cytokine production in response to LPS. These molecules might thereby provide a new therapeutic strategy in the context of AKI with sepsis.
The Quantitative Proteome of the Cement and Adhesive Gland of the Pedunculate Barnacle, Pollicipes pollicipes
Authors: Domínguez-Pérez Dany , Almeida Daniela , Wissing Josef , Machado André M. , Jänsch Lothar , Castro Luís Filipe , Antunes Agostinho , Vasconcelos Vitor , Campos Alexandre , Cunha Isabel
Published: April 2020

Adhesive secretion has a fundamental role in barnacles’ survival, keeping them in an adequate position on the substrate under a variety of hydrologic regimes. It arouses special interest for industrial applications, such as antifouling strategies, underwater industrial and surgical glues, and dental composites. This study was focused on the goose barnacle Pollicipes pollicipes adhesion system, a species that lives in the Eastern Atlantic strongly exposed intertidal rocky shores and cliffs. The protein composition of P. pollicipes cement multicomplex and cement gland was quantitatively studied using a label-free LC-MS high-throughput proteomic analysis, searched against a custom transcriptome-derived database. Overall, 11,755 peptide sequences were identified in the gland while 2880 peptide sequences were detected in the cement, clustered in 1616 and 1568 protein groups, respectively. The gland proteome was dominated by proteins of the muscle, cytoskeleton, and some uncharacterized proteins, while the cement was, for the first time, reported to be composed by nearly 50% of proteins that are not canonical cement proteins, mainly unannotated proteins, chemical cues, and protease inhibitors, among others. Bulk adhesive proteins accounted for one-third of the cement proteome, with CP52k being the most abundant. Some unannotated proteins highly expressed in the proteomes, as well as at the transcriptomic level, showed similar physicochemical properties to the known surface-coupling barnacle adhesive proteins while the function of the others remains to be discovered. New quantitative and qualitative clues are provided to understand the diversity and function of proteins in the cement of stalked barnacles, contributing to the whole adhesion model in Cirripedia.
CDK6 Inhibition: A Novel Approach in AML Management
Authors: Uras Iris Z. , Sexl Veronika , Kollmann Karoline
Published: April 2020

Acute myeloid leukemia (AML) is a complex disease with an aggressive clinical course and high mortality rate. The standard of care for patients has only changed minimally over the past 40 years. However, potentially useful agents have moved from bench to bedside with the potential to revolutionize therapeutic strategies. As such, cell-cycle inhibitors have been discussed as alternative treatment options for AML. In this review, we focus on cyclin-dependent kinase 6 (CDK6) emerging as a key molecule with distinct functions in different subsets of AML. CDK6 exerts its effects in a kinase-dependent and -independent manner which is of clinical significance as current inhibitors only target the enzymatic activity.
Maize ZmFNSI Homologs Interact with an NLR Protein to Modulate Hypersensitive Response
Authors: Zhu Yu-Xiu , Ge Chunxia , Ma Shijun , Liu Xiao-Ying , Liu Mengjie , Sun Yang , Wang Guan-Feng
Published: April 2020

Nucleotide binding, leucine-rich-repeat (NLR) proteins are the major class of resistance (R) proteins used by plants to defend against pathogen infection. The recognition between NLRs and their cognate pathogen effectors usually triggers a rapid localized cell death, termed the hypersensitive response (HR). Flavone synthase I (FNSI) is one of the key enzymes in the flavone biosynthesis pathway. It also displays salicylic acid (SA) 5-hydroxylase (S5H) activity. A close homolog of FNSI/S5H displays SA 3-hydroxylase (S3H) activity. Both FNSI/S5H and S3H play important roles in plant innate immunity. However, the underlying molecular mechanisms and the relationship between S5H and S3H with the NLR-mediated HR are not known in any plant species. In this study, we identified three genes encoding ZmFNSI-1, ZmFNSI-2 and ZmS3H that are significantly upregulated in a maize line carrying an autoactive NLR Rp1-D21 mutant. Functional analysis showed that ZmFNSI-1 and ZmFNSI-2, but not ZmS3H, suppressed HR conferred by Rp1-D21 and its signaling domain CCD21 when transiently expressed in N. benthamiana. ZmFNSI-1 and ZmFNSI-2 physically interacted with CCD21. Furthermore, ZmFNSI-1 and ZmFNSI-2 interacted with HCT, a key enzyme in lignin biosynthesis pathway, which can also suppress Rp1-D21-mediated HR. These results lay the foundation for the further functional analysis of the roles of FNSI in plant innate immunity.
Newborn Screening for Pompe Disease
Authors: Sawada Takaaki , Kido Jun , Nakamura Kimitoshi
Published: April 2020

Glycogen storage disease type II (also known as Pompe disease (PD)) is an autosomal recessive disorder caused by defects in α-glucosidase (AαGlu), resulting in lysosomal glycogen accumulation in skeletal and heart muscles. Accumulation and tissue damage rates depend on residual enzyme activity. Enzyme replacement therapy (ERT) should be started before symptoms are apparent in order to achieve optimal outcomes. Early initiation of ERT in infantile-onset PD improves survival, reduces the need for ventilation, results in earlier independent walking, and enhances patient quality of life. Newborn screening (NBS) is the optimal approach for early diagnosis and treatment of PD. In NBS for PD, measurement of AαGlu enzyme activity in dried blood spots (DBSs) is conducted using fluorometry, tandem mass spectrometry, or digital microfluidic fluorometry. The presence of pseudodeficiency alleles, which are frequent in Asian populations, interferes with NBS for PD, and current NBS systems cannot discriminate between pseudodeficiency and cases with PD or potential PD. The combination of GAA gene analysis with NBS is essential for definitive diagnoses of PD. In this review, we introduce our experiences and discuss NBS programs for PD implemented in various countries.
Stiffness and Strength Improvement of Geosynthetic-Reinforced Pavement Foundation Using Large-Scale Wheel Test
Authors: Wright Jason , Kim S. Sonny , Kim Bumjoo
Published: April 2020

Laboratory cyclic plate load tests are commonly used in the assessment of geosynthetic performance in pavement applications due to the repeatability of testing results and the smaller required testing areas than traditional Accelerated Pavement Testing facilities. While the objective of traditional plate load testing procedure is to closely replicate traffic conditions, the reality is that rolling wheel loads produce different stresses in pavement layers than traditional cyclic plate load tests. This two-fold study investigates the differences between the stress response of subgrade soil from a rolling wheel load (replicating rolling traffic conditions) and a unidirectional dynamic load (replicating traditional plate load test procedures) in order to obtain a more realistic stress response of pavement layers from rolling wheel traffic. Ultimately, results show that the testing specimens that experienced rolling wheel loading had an average of 17% higher pressure measurements in the top of the subgrade than vertically loaded (unidirectional dynamic load) specimens. The second segment of this study is used in conjunction with the first to analyze aggregate base material behavior when using a geosynthetic for reinforcement. The study aimed to determine the difference in the post-trafficked strength and stiffness of pavement foundation. A Dynamic Cone Penetrometer and Light Weight Deflectometer were utilized to determine material changes from this trafficking and revealed that all specimens that included a geosynthetic had a higher base stiffness and strength while the specimen with geotextile and geogrid in combination created the highest stiffness and strength after large-scale rolling wheel trafficking.
Within-Tree Distribution and Survival of the Eucalyptus Longhorned Borer Phoracantha semipunctata (Coleoptera: Cerambycidae) in a Mediterranean-Type Ecosystem
Authors: Seaton Stephen , Matusick George , Hardy Giles
Published: April 2020

The attack patterns, infestation success and larval development of woodborers within living trees are complex and are largely shaped by host tree characteristics. Following a severe drought in a native eucalypt forest where outbreak densities of a native Australian beetle, the eucalyptus longhorned borer (Phoracantha semipunctata), occurred, a tree dissection study was conducted in Australia. This involved felling 40 trees each of jarrah (Eucalyptus marginata) and marri (Corymbia calophylla) that were cut into 1-m sections and neonate larval galleries, larvae in pupal cells and adult borer emergence were measured and added to give total numbers per tree to determine the within-tree distribution and survival of P. semipunctata. There was a significant impact on larval survival in both species, in contrast, pupal survival remained high. Within-tree distribution of P. semipunctata was directional with borer emergence and incidence of larval galleries both negatively associated with tree section height above the ground and positively associated with section diameter and bark thickness, reaching a maximum towards the base of trees. High incidence and survival in lower thicker tree sections indicate a more conducive environment for larval development, in contrast to poor larval survival in smaller thinner sections at the top of trees. The dependence of larval survival on tree characteristics controlling the within-tree distribution of borer emergence is emphasized, and needs to be considered when estimating the spread of borer populations during outbreaks.
Changing Microarthropod Communities in Front of a Receding Glacier in the High Arctic
Authors: Gwiazdowicz Dariusz J. , Zawieja Bogna , Olejniczak Izabella , Skubała Piotr , Gdula Anna K. , Coulson Stephen J.
Published: April 2020

This study was carried out at Ny-Ålesund on Spitsbergen in Svalbard (High Arctic). Eight study sites were established along a transect from the fjord to the snout of the glacier. The sites differed from each other by the type of vegetation cover and soil characteristics. Soil samples were collected and placed in Tullgren funnels. Extracted arthropods were represented by two groups of mites (Mesostigmata and Oribatida) and springtails (Collembola). The pioneer species that occurred first after retreat of the glacier were representatives of the Collembola (Agrenia bidenticulata and Hypogastrura concolor). Later, other springtails appeared including Folsomia alpha, Folsomia quadrioculata, Hypogastrura concolor, Isotoma anglicana, Sminthurinus concolor and the first species of oribatid mites; Camisia foveolata and Tectocepheus velatus velatus. Arthropod communities recorded along the transect were characterized by large variations in both species composition and abundance of individuals. The greater the distance from the glacier snout, the greater the species richness (2 to 22 species). The mean number of species per sample was the lowest at site 8 (1 ± 0.71) (the closest to the glacier) and greatest at site 1 (14 ± 1.41) (furthest from the glacier). The Simpson’s diversity index (D) was distinctly greater at sites 1 (4.61 ± 0.06) and 3 (3.94 ± 0.11) than at other sites, especially site 8 (1.07 ± 0.06). Densities were least in the samples closest to the glacier (30 to 101 individuals; density 3000–10,100 individuals/m2). At the other locations, abundance was highly variable (905 to 7432 individuals; density 90,500–743,200 individuals/m2). The mean abundances were greatest at sites 2 and 3. The great variations in total abundances observed were often due to the presence or absence of one or more dominant species exhibiting extreme abundance variability between sites. The microarthropod community of the High Arctic is composed of heterogeneous circumpolar species, yet on a landscape scale is extremely dependent on local environmental conditions which may be subject to rapid change.
Assessing Operability on Berthed Ships. Common Approaches, Present and Future Lines
Authors: Molina-Sanchez Rafael , Campos Álvaro , de Alfonso Marta , de los Santos Francisco J. , Rodríguez-Rubio Pablo , Pérez-Rubio Susana , Camarero-Orive Alberto , Álvarez-Fanjul Enrique
Published: April 2020

The revenue of a ship company, a terminal, a port and even the whole logistic chain largely depends on the performance of (un)loading operations inside port areas. However, they are conditioned by met-ocean agents that exert stresses on fixed structures, berthed ships and mooring systems that can affect the comfort, productivity and safety of the operations. Under extreme conditions, operations may be interrupted, producing periods of inactivity, economic losses and even jeopardizing the terminal’s reliability. Therefore, it is crucial to develop strategies for characterizing and predicting operability in docks and anchorages. The present paper aims to assess the main approaches up to date to address the operability on berthed ships and to explore present and future strategies. To accomplish this, main factors affecting the operability are reviewed and different methodologies for the characterization and calculation of operability are detailed, together with some results regarding the perception of vulnerability from the Spanish port community. Rather than aiming for generic mono-parametric thresholds, the results highlight the need for addressing this challenge in a specific way for each dock and anchorage, broadening field monitoring and considering the varied peculiarities and the specific perception and experience of main port’s actors.
Tribology of Natural Fibers Composite Materials: An Overview
Authors: Milosevic Marko , Valášek Petr , Ruggiero Alessandro
Published: April 2020

In the framework of green materials, in recent years, natural fiber composites attracted great attention of academia and industry. Their mechanical and tribological characteristics, such as high strength, elasticity, friction, and wear resistance, make them suitable for a wide range of industrial applications in which issues regarding a large amount of disposal are to be considered since their environmental friendliness gives them an advantage over conventional synthetic materials. Based on the recent and relevant investigations found in the scientific literature, an overview focused on the tribological characteristics of composite materials reinforced with different types of natural fibers is presented. The aim is to introduce the reader to the issues, exploring the actual knowledge of the friction and wear characteristics of the composites under the influence of different operating parameters, as well as the chemical treatment of fibers. The main experimental tribological techniques and the main used apparatus are also discussed, with the aim of highlighting the most appropriate future research directions to achieve a complete framework on the tribological behavior of many possible natural fiber composite materials.
Effects of Methylenediphenyl 4,4’-Diisocyanate and Maleic Anhydride as Coupling Agents on the Properties of Polylactic Acid/Polybutylene Succinate/Wood Flour Biocomposites by Reactive Extrusion
Authors: Seo Young-Rok , Bae Sang-U , Gwon Jaegyoung , Wu Qinglin , Kim Birm-June
Published: April 2020

Polylactic acid (PLA)/polybutylene succinate (PBS)/wood flour (WF) biocomposites were fabricated by in situ reactive extrusion with coupling agents. Methylenediphenyl 4,4’-diisocyanate (MDI) and maleic anhydride (MA) were used as coupling agents. To evaluate the effects of MDI and MA, various properties (i.e., interfacial adhesion, mechanical, thermal, and viscoelastic properties) were investigated. PLA/PBS/WF biocomposites without coupling agents revealed poor interfacial adhesion leading to deteriorated properties. However, the incorporation of MDI and/or MA into biocomposites showed high performances by increasing interfacial adhesion. For instance, the incorporation of MDI resulted in improved tensile, flexural, and impact strengths and an increase in tensile and flexural modulus was observed by the incorporation of MA. Specially, remarkably improved thermal stability was found in the PLA/PBS/WF biocomposites with 1 phr MDI and 1 phr MA. Also, the addition of MDI or MA into biocomposites increased the glass transition temperature and crystallinity, respectively. For viscoelastic property, the PLA/PBS/WF biocomposites with 1 phr MDI and 1 phr MA achieved significant enhancement in storage modulus compared to biocomposites without coupling agents. Therefore, the most balanced performances were evident in the PLA/PBS/WF biocomposites with the hybrid incorporation of small quantities of MDI and MA.
Evaluation of Surface Roughness and Defect Formation after The Machining of Sintered Aluminum Alloy AlSi10Mg
Authors: Struzikiewicz Grzegorz , Sioma Andrzej
Published: April 2020

This article presents selected issues related to the workpiece surface quality after machining by the laser sintering of AlSi10MG alloy powder. The surfaces of the workpiece were prepared and machined by longitudinal turning with tools made of sintered carbides. The occurrence of breaches on the machined material surface was found, which negatively influence the values of 3D surface roughness parameters. The occurring phenomena were analyzed and proposals for their explanation were made. Guidelines for the machining of workpieces achieved by the laser sintering of powders were developed. The lowest value of the 3D roughness parameters was obtained for f = 0.06 mm/rev, ap = 0.5–1.0 mm, and for the nose radius of cutting insert rε = 0.8 mm. The results of research on the effect of cutting parameters on the values of parameters describing the surface quality are presented. Topography measurements and 3D surface roughness parameters are presented, as well as the results of a microscopic 3D surface analysis. Taguchi’s method was used in the research methodology.
A Modified Iterative Automatic Method for Characterization at Shear Resonance: Case Study of Ba0.85Ca0.15Ti0.90Zr0.10O3 Eco-Piezoceramics
Authors: Pardo Lorena , Reyes-Montero Armando , García Álvaro , Jacas-Rodríguez Alfredo , Ochoa Pilar , González Amador M. , Jiménez Francisco J. , Vázquez-Rodríguez Manuel , Villafuerte-Castrejón María E.
Published: April 2020

Coupling between electrically excited electromechanical resonances of piezoelectric ceramics is undesirable for the purpose of their characterization, since the material models correspond to monomodal resonances. However, coupling takes place quite often and it is unavoidable at the shear resonance of standard in-plane poled and thickness-excited rectangular plates. The piezoelectric coefficient e15, the elastic compliance s55E and the dielectric permittivity component ε11S for a piezoelectric ceramic can be determined, including all losses, using the automatic iterative method of analysis of the complex impedance curves for the shear mode of an appropriated resonator. This is the non-standard, thickness-poled and longitudinally excited, shear plate. In this paper, the automatic iterative method is modified. The purpose is to be able to deal with the analysis of the impedance curves of the non-standard plate as the periodic phenomena of coupling and decoupling of the main shear resonance and other resonances takes place. This happens when the thickness of the plate is reduced, and its aspect ratio (width of the excitation (w)/thickness for poling (t)) is increased. In this process, the frequency of the shear resonance also increases and meets those of other plate modes periodically. We aim to obtain the best approach for the shear properties of near coupling and to reveal both their validity and the limitations of the thus-obtained information. Finally, we use a plate of a Ba0.85Ca0.15Ti0.90Zr0.10O3 eco-piezoceramic as a case study.
Optimizing Manufacturing and Osseointegration of Ti6Al4V Implants through Precision Casting and Calcium and Phosphorus Ion Implantation? In Vivo Results of a Large-Scale Animal Trial
Authors: JV Wölfle-Roos , B Katmer Amet , J Fiedler , H Michels , G Kappelt , A Ignatius , L Dürselen , H Reichel , RE Brenner
Published: April 2020

Background: Uncemented implants are still associated with several major challenges, especially with regard to their manufacturing and their osseointegration. In this study, a novel manufacturing technique—an optimized form of precision casting—and a novel surface modification to promote osseointegration—calcium and phosphorus ion implantation into the implant surface—were tested in vivo. Methods: Cylindrical Ti6Al4V implants were inserted bilaterally into the tibia of 110 rats. We compared two generations of cast Ti6Al4V implants (CAST 1st GEN, n = 22, and CAST 2nd GEN, n = 22) as well as cast 2nd GEN Ti6Al4V implants with calcium (CAST + CA, n = 22) and phosphorus (CAST + P, n = 22) ion implantation to standard machined Ti6Al4V implants (control, n = 22). After 4 and 12 weeks, maximal pull-out force and bone-to-implant contact rate (BIC) were measured and compared between all five groups. Results: There was no significant difference between all five groups after 4 weeks or 12 weeks with regard to pull-out force (p > 0.05, Kruskal Wallis test). Histomorphometric analysis showed no significant difference of BIC after 4 weeks (p > 0.05, Kruskal–Wallis test), whereas there was a trend towards a higher BIC in the CAST + P group (54.8% ± 15.2%), especially compared to the control group (38.6% ± 12.8%) after 12 weeks (p = 0.053, Kruskal–Wallis test). Conclusion: In this study, we found no indication of inferiority of Ti6Al4V implants cast with the optimized centrifugal precision casting technique of the second generation compared to standard Ti6Al4V implants. As the employed manufacturing process holds considerable economic potential, mainly due to a significantly decreased material demand per implant by casting near net-shape instead of milling away most of the starting ingot, its application in manufacturing uncemented implants seems promising. However, no significant advantages of calcium or phosphorus ion implantation could be observed in this study. Due to the promising results of ion implantation in previous in vitro and in vivo studies, further in vivo studies with different ion implantation conditions should be considered.
Elucidation of Antimicrobial Activity of Non-Covalently Dispersed Carbon Nanotubes
Authors: Saleemi Mansab Ali , Fouladi Mohammad Hosseini , Yong Phelim Voon Chen , Wong Eng Hwa
Published: April 2020

Microorganisms have begun to develop resistance because of inappropriate and extensive use of antibiotics in the hospital setting. Therefore, it seems to be necessary to find a way to tackle these pathogens by developing new and effective antimicrobial agents. Carbon nanotubes (CNTs) have attracted growing attention because of their remarkable mechanical strength, electrical properties, and chemical and thermal stability for their potential applications in the field of biomedical as therapeutic and diagnostic nanotools. However, the impact of carbon nanotubes on microbial growth has not been fully investigated. The primary purpose of this research study is to investigate the antimicrobial activity of CNTs, particularly double-walled and multi-walled nanotubes on representative pathogenic strains such as Gram-positive bacteria Staphylococcus aureus, Gram-negative bacteria Pseudomonas aeruginosa, Klebsiella pneumoniae, and fungal strain Candida albicans. The dispersion ability of CNT types (double-walled and multi-walled) treated with a surfactant such as sodium dodecyl-benzenesulfonate (SDBS) and their impact on the microbial growth inhibition were also examined. A stock concentration 0.2 mg/mL of both double-walled and multi-walled CNTs was prepared homogenized by dispersing in surfactant solution by using probe sonication. UV-vis absorbance, Fourier transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM) were used for the characterization of CNTs dispersed in the surfactant solution to study the interaction between molecules of surfactant and CNTs. Later, scanning electron microscopy (SEM) was used to investigate how CNTs interact with the microbial cells. The antimicrobial activity was determined by analyzing optical density growth curves and viable cell count. This study revealed that microbial growth inhibited by non-covalently dispersed CNTs was both depend on the concentration and treatment time. In conclusion, the binding of surfactant molecules to the surface of CNTs increases its ability to disperse in aqueous solution. Non-covalent method of CNTs dispersion preserved their structure and increased microbial growth inhibition as a result. Multi-walled CNTs exhibited higher antimicrobial activity compared to double-walled CNTs against selected pathogens.
Chitosan/Graphene Oxide Nanocomposite Membranes as Adsorbents with Applications in Water Purification
Authors: Croitoru Alexa-Maria , Ficai Anton , Ficai Denisa , Trusca Roxana , Dolete Georgiana , Andronescu Ecaterina , Turculet Stefan Claudiu
Published: April 2020

The scope of this article is to develop composite membranes using chitosan (CS) and graphene oxide (GO) as adsorbents for the removal of inorganic pollutants such as heavy metal ions, particularly Pb2+, from aqueous solutions. GO was obtained by modified Hummers method and blended with CS solution. The introduction of ethylenediaminetetraacetic acid (EDTA) compound to CS/GO suspension lead to an increased adsorption capacity of CS/GO for the elimination of heavy metals by forming stable chelates with them. The synthesized membranes were examined by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM), and the adsorption behaviour of Pb2+ from aqueous solutions using CS/EDTA/GO membranes was evaluated using inductively coupled plasma mass spectrometry (ICP-MS). The adsorption performance of Pb2+ ions was studied by monitoring the concentration of Pb2+ against the adsorption period at an initial content of the adsorbent. The maximum adsorption efficiency of Pb2+ metal ions reached 767 mg·g−1 for CS/EDTA/GO 0.1%, 889 mg·g−1 for CS/EDTA/GO 0.3%, 970 mg·g−1 for CS/EDTA, 853 mg·g−1 for CS and 1526 mg·g−1 for GO. These findings show promising potential for CS/EDTA/GO membranes as effective adsorbent materials for the removal of heavy metal ions in water.
Analysis of a New Shape of Test Specimen for Block Shear Impact Test
Authors: Komorek Andrzej , Godzimirski Jan , Rośkowicz Marek
Published: April 2020

This paper reports and discusses an experimental comparison of metal specimens for impact strength research of adhesive connections with different shapes of the upper element. The top element of the specimen of the cuboid shape was replaced with a disc-shaped element. The experimental investigations were supplemented with dynamic numerical calculations of the tested cases. The results of the experimental studies indicate that the material applied to the produce of the top element of the block specimen deformed plastically as a result of applying the load, which further hinders the interpretation of already problematic investigation results. The numerical analysis confirms exceeding the yield point, by stresses, of the material that the specimen elements were made of. Modified specimens were characterized by only little greater repeatability of test results and greater impact strength caused by plastic deformations of the cylindrical specimen element.
Are Zirconia Bioceramics and Ceramics Intended to Come in Contact with Skin Inert?
Authors: Reclaru Lucien , Ardelean Lavinia Cosmina , Miu Catalin Adrian , Grecu Alexandru Florian
Published: April 2020

Generally speaking, ceramic materials are insensitive to corrosion, compared to most other materials. The present study questions the fact that ceramics are inert. Two major aspects are to be considered: the stability of zirconia over time, the stable tetragonal phase transforming into an unstable monoclinic form; the multitude of manufacturing methods, using various additives, sintering additives, oxides mixing, impurities, grain boundaries, and porosities which strongly influence the corrosion behavior and chemical degradation. In case of the investigated ceramics two paths were pursued:a) Dissolutions of ceramics in a mixture of HNO3 60% and HF 40% ultrapure medium.b) Release of cations from ceramics in various mediums:dental bioceramics in a 0.07 M HCl medium and a 0.1% NaF+0.1% KF medium; ceramics used in jewelry and watchmaking applications in a HCl 0.07 M medium and an artificial sweat medium. By inductively coupled plasma-optical emission spectrometry/mass spectrometry (ICP-OES/MS), traces of significant chemical elements were assessed: Hf, Cr, Y, As, Pb, Al, Fe, Cu, Se, Sb, La, Ni, Co, Sb, Ta, Te, Ba, Sm, Nb, Hg, Cd, Sr, As and Se. In ceramics used in jewelry and watchmaking applications the concentrations found vary from one ceramic to another, including toxic elements such as Te, Ba, As, Pb, Sm, Hg and Cd, therefore being technical zirconia ceramics which are not intended for the medical field. For ceramics used in jewelry and watchmaking applications a screening identification test for Ni, Co, Cu and Fe with strips of type Merckoquant® (Merck, Kenilworth, NJ, USA) was also performed. The obtained data prove that the zirconia ceramics in question are far from being “inert”.
Manipulation of TiO2 Nanoparticle/Polymer Coatings Wettability and Friction in Different Environments
Authors: Conradi Marjetka , Kocijan Aleksandra , Kosec Tadeja , Podgornik Bojan
Published: April 2020

An AISI 316L surface was functionalized by the adsorption of hydrophilic epoxy and epoxy/TiO2/epoxy coatings and hydrophobic epoxy/fluoroalkylsilane-functionalized FAS-TiO2/epoxy coatings. We characterized the coatings’ wettability, morphology and average surface roughness and discussed the influence of surface wettability and morphology on the coefficient of friction and the wear resistance. Experiments were performed in dry, distilled water and in a simulated physiological solution (Hank’s solution). In the case of dry sliding, a lower coefficient of friction is achieved for both TiO2 coatings compared to the pure epoxy coating. In a water environment the same level of friction is shown for all three coatings, whereas in Hank’s solution the friction is reduced for the hydrophilic epoxy/TiO2/epoxy coating, increased for the hydrophobic epoxy/FAS-TiO2/epoxy coating and has no effect on the pure epoxy coating. The results show that the corrosion resistance is significantly improved for the hydrophobic epoxy/FAS-TiO2/epoxy coating compared to the hydrophilic pure epoxy and epoxy/TiO2/epoxy coatings.
Experimental and Numerical Analyses of the Failure of Prestressed Concrete Railway Sleepers
Authors: Silva Ramon , Silva Welington V. , Farias Jonas Yamashita de , Santos Marcos Aires A. , Neiva Leonardo O.
Published: April 2020

This paper carries out the assessment of load-carrying capacity of prestressed concrete sleepers, in accordance with Brazilian Standard (ABNT NBR 11709) and AREMA Standard. In a lot of railways around the world, many prestressed concrete sleepers have failed due to Rail Seat Abrasion (RSA) and corrosion. RSA is the wear degradation underneath the rail on the surface of prestressed concrete sleepers. In this paper, a numerical study was carried out to evaluate the load-carrying capacity of the prestressed concrete sleepers, using ABAQUS software. The nonlinear using Concrete Damage Plasticity model was validated by 18 experimental results, in accordance to standards. Using the validated model, the influence of different wear depth RSA, combined with corrosion of the prestressed wires, is investigated.
Distance and Similarity Measures for Spherical Fuzzy Sets and Their Applications in Selecting Mega Projects
Authors: Khan Muhammad Jabir , Kumam Poom , Deebani Wejdan , Kumam Wiyada , Shah Zahir
Published: April 2020

A new condition on positive membership, neutral membership, and negative membership functions give us the successful extension of picture fuzzy set and Pythagorean fuzzy set and called spherical fuzzy sets ( SFS ) . This extends the domain of positive membership, neutral membership, and negative membership functions. Keeping in mind the importance of similarity measure and application in data mining, medical diagnosis, decision making, and pattern recognition, several studies on similarity measures have been proposed in the literature. Some of those, however, cannot satisfy the axioms of similarity and provide counter-intuitive cases. In this paper, we proposed the set-theoretic similarity and distance measures. We provide some counterexamples for already proposed similarity measures in the literature and shows that how our proposed method is important and applicable to the pattern recognition problems. In the end, we provide an application of a proposed similarity measure for selecting mega projects in under developed countries.
Some Connections between Classical and Nonclassical Symmetries of a Partial Differential Equation and Their Applications
Authors: Temuer Chaolu , Tong Laga , Bluman George
Published: April 2020

Essential connections between the classical symmetry and nonclassical symmetry of a partial differential equations (PDEs) are established. Through these connections, the sufficient conditions for the nonclassical symmetry of PDEs can be derived directly from the inconsistent conditions of the system determining equations of the classical symmetry of the PDE. Based on the connections, a new algorithm for determining the nonclassical symmetry of a PDEs is proposed. The algorithm make the determination of the nonclassical symmetry easier by adding compatibility extra equations obtained from system of determining equations of the classical symmetry to the system of determining equations of the nonclassical symmetry of the PDE. The findings of this study not only give an alternative method to determine the nonclassical symmetry of a PDE, but also can help for better understanding of the essential connections between classical and nonclassical symmetries of a PDE. Concurrently, the results obtained here enhance the efficiency of the existing algorithms for determining the nonclassical symmetry of a PDE. As applications of the given algorithm, a nonclassical symmetry classification of a class of generalized Burgers equations and the nonclassical symmetries of a KdV-type equations are given within a relatively easier way and some new nonclassical symmetries have been found for the Burgers equations.
Composition Methods for Dynamical Systems Separable into Three Parts
Authors: Casas Fernando , Escorihuela-Tomàs Alejandro
Published: April 2020

New families of fourth-order composition methods for the numerical integration of initial value problems defined by ordinary differential equations are proposed. They are designed when the problem can be separated into three parts in such a way that each part is explicitly solvable. The methods are obtained by applying different optimization criteria and preserve geometric properties of the continuous problem by construction. Different numerical examples exhibit their improved performance with respect to previous splitting methods in the literature.
Some Fractional Hermite–Hadamard Type Inequalities for Interval-Valued Functions
Authors: Shi Fangfang , Ye Guoju , Zhao Dafang , Liu Wei
Published: April 2020

In this paper, firstly we prove the relationship between interval h-convex functions and interval harmonically h-convex functions. Secondly, several new Hermite–Hadamard type inequalities for interval h-convex functions via interval Riemann–Liouville type fractional integrals are established. Finally, we obtain some new fractional Hadamard–Hermite type inequalities for interval harmonically h-convex functions by using the above relationship. Also we discuss the importance of our results and some special cases. Our results extend and improve some previously known results.
Short Remarks on Complete Monotonicity of Some Functions
Authors: Matejíčka Ladislav
Published: April 2020

In this paper, we show that the functions x m | β ( m ) ( x ) | are not completely monotonic on ( 0 , ∞ ) for all m ∈ N , where β ( x ) is the Nielsen’s β -function and we prove the functions x m − 1 | β ( m ) ( x ) | and x m − 1 | ψ ( m ) ( x ) | are completely monotonic on ( 0 , ∞ ) for all m ∈ N , m > 2 , where ψ ( x ) denotes the logarithmic derivative of Euler’s gamma function.