bluuebunny/crossref_metadata_2025 huggingface dataset:
Importance of Social- and Health-Related Problems: Do Spaniards Give Them the Significance They Actually Deserve?
Authors: Alonso Francisco , Esteban Cristina , Serge Andrea , Tortosa Macarena
Published: October 2019

Social and health problems imply an impact on society. The main objective of this study is to provide an overview of how Spanish people perceive cancer, terrorism, cardiovascular diseases, crime, AIDS, drugs, and traffic accidents, finding out whether they assess the importance of these issues in correspondence with their actual severity. The study used a full sample of 1206 Spaniards (51.6% females and 48.4% males) who responded to a computer-assisted telephone interviewing (CATI) survey on the significance of these social and health-related problems, assessed through a zero to ten Likert scale. The perceived severity of the problems was considered taking into account the official data of deaths reported by governmental institutions. For the comparison of mean values, the One-way Analysis of Variance (ANOVA) test was used. Results show high average values for all the problems. The most concerning elements are cancer (M = 9.28 ± 1.24) and terrorism (M = 9.22 ± 1.47). Cardiovascular diseases have the lowest scores (M = 8.29 ± 1.64). There is a good adjustment between real and subjective perception, but some issues are either underestimated or overestimated. Women assessed all of them as more important than men, and people over 65 gave all the issues more value than younger people. It is important that Spaniards understand the objective severity of these issues, thus allowing for more interventions by governments, education, and mass media.
Recruiting the “Heavy-Using Loyalists of Tomorrow”: An Analysis of the Aims, Effects and Mechanisms of Alcohol Advertising, Based on Advertising Industry Evaluations
Authors: Maani Hessari Nason , Bertscher Adam , Critchlow Nathan , Fitzgerald Niamh , Knai Cécile , Stead Martine , Petticrew Mark
Published: October 2019

Restricting alcohol advertising and marketing is a cost-effective intervention for reducing alcohol harms. However, the alcohol industry maintains that advertising does not affect consumption, claiming that its purpose is to help consumers choose brands, it is not aimed at young people, it only promotes “responsible consumption”, and any relationships with consumption are not causal. We reviewed 39 case studies (1981–2016) published by the advertising industry, which evaluate the effects of alcohol advertising campaigns. We used these to examine these industry claims. 30/39 (77%) of the case studies mentioned increasing/maintaining market share as an objective, or used this to assess the effectiveness of advertising campaigns. Most (25/39, 64%) found that campaigns increased consumption-related outcomes. Some campaigns targeted women, and heavy drinkers (e.g., Stella Artois lager, Famous Grouse whisky). Campaigns often (13/39, 33%) targeted younger drinkers. These data show that advertising does influence market share. Other effects reported in the case studies include changing the consumer profile towards: younger drinkers, women, new/lapsed drinkers, and heavy drinkers. They also present evidence of a causal relationship between advertising and consumption. In conclusion, this analysis, based on industry data, presents significant new evidence on (i) the effects of alcohol advertising on consumption-related outcomes, and (ii) the mechanisms by which it achieves those effects.
Measuring Health Vulnerability: An Interdisciplinary Indicator Applied to Mainland Portugal
Authors: Oliveira Gisela M. , Vidal Diogo Guedes , Ferraz Maria Pia , Cabeda José Manuel , Pontes Manuela , Maia Rui Leandro , Calheiros José Manuel , Barreira Esmeralda
Published: October 2019

Health promotion and inequality reduction are specific goals of the United Nations 2030 Agenda, which are interconnected with several dimensions of life. This work proposes a composite index SEHVI—socioeconomic health vulnerability index—to address Portuguese population socioeconomic determinants that affect health outcomes. Variables composing SEHVI are aligned with the sustainable development goals considering data and times series availability to enable progress monitoring, and variables adequacy to translate populations’ life conditions affecting health outcomes. Data for 35 variables and three periods were collected from official national databases. All variables are part of one of the groups: Health determinants (social, economic, cultural, and environmental factors) and health outcomes (mortality indicators). Variables were standardized and normalized by “Distance to a reference” method and then aggregated into the SEHVI formula. Several statistical procedures for validation of SEHVI revealed the internal consistency of the index. For all municipalities, SEHVI was calculated and cartographically represented. Results were analyzed by statistical tests and compared for three years and territory typologies. SEHVI differences were found as a function of population density, suggesting inequalities of communities’ life conditions and in vulnerability to health.
Land Suitability Evaluation and an Interval Stochastic Fuzzy Programming-Based Optimization Model for Land-Use Planning and Environmental Policy Analysis
Authors: Zhang Zuo , Zhou Min , Ou Guoliang , Tan Shukui , Song Yan , Zhang Lu , Nie Xin
Published: October 2019

People explosion and fast economic growth are bringing a more serious land resource shortage crisis. Rational land-use allocation can effectively reduce this burden. Existing land-use allocation models may deal with a lot of challenges of land-use planning. This study proposed a hybrid quantitative and spatial optimization land-use allocation model that could enrich the land-use allocation method system. This model has three advantages compared to former methods: (1) this model can simultaneously solve the quantitative land area optimization problem and spatial allocation problem, which are the two core aspects of land-use allocation; (2) the land suitability assessment method considers various geographical, economic and environmental factors which are essential to land-use allocation; (3) this model used an interval stochastic fuzzy programming land-use allocation model to solve the quantitative land area optimization problem. This model not only considers three uncertainties in the natural system but also involves various economic, social, ecological and environmental constraints—most of which are specifically put into the optimization process. The proposed model has been applied to a real case study in Liannan county, Guangdong province, China. The results could help land managers and decision makers to conduct sound land-use planning/policy and could help scientists understand the inner contradiction among economic development, environmental protection, and land use.
Calculation for Multidimensional Topological Relations in 3D Cadastre Based on Geometric Algebra
Authors: Shi Zhifeng , Hu Di , Yin Pengcheng , Wang Chun , Chen Taisheng , Zhang Jiyi
Published: October 2019

Maintaining topological consistency is a crucial issue for 3D cadastral modeling as this helps to represent the cadastral boundary clearly and accurately. As a result, 3D cadastral data models are mainly built on the basis of topological models that allow topology to be expressed clearly. However, topological models in Euclidean space cannot directly represent objects’ geometric information. As geometric information is important in 3D spatial analysis, 3D cadastral data models based on topological models cannot realize topological calculation and analysis. Previous research has proved that geometric and topological information for cadastral objects can be integrated and represented by conformal geometric algebra (CGA) expressions. This paper aims to realize 3D topological analysis in the cadastral field using CGA’s advantages in geometric relations computation. A calculation framework is designed on the basis of the outer product to achieve the purpose of multidimensional unity for 3D cadastral topological analysis in this paper. A calculation framework of topological relations between a boundary point (or a boundary line) and a cadastral parcel is developed. A total of 13 types of topological relations between a boundary point and a cadastral parcel and 48 types of topological relations between a boundary line and a cadastral parcel are obtained. The study indicates that the advantages of CGA in multidimensional unified representation and calculation can be used to solve problems encountered by topological models in Euclidean space.
The Spill Over of Crime from Urban Centers: An Account of the Changing Spatial Distribution of Violent Crime in Guyana
Authors: Cummings Anthony R. , Markandey Nakul , Das Hannah , Arredondo Celina , Wehenkel Aaran , Tiemann Brittany L. , Lee Giyol
Published: October 2019

As the rate of crime decelerates in the developed world, the opposite phenomenon is being observed in the developing world, including Latin America and the Caribbean. Crime in Latin America and the Caribbean has been concentrated in urban settings, but the expertise for studying crime and providing guidance on policing remain heavily rooted in the developed world. A hindrance to studying crime in the developing world is the difficulty in obtaining official data, allowing for generalizations on where crime is concentrated to persist. This paper tackles two challenges facing crime analysis in the developing world: the availability of data and an examination of whether crime is concentrated in urban settings. We utilized newspaper archival data to study the spatial distribution of crime in Guyana, South America, across the landscape, and in relation to rural indigenous villages. Three spatial analysis tools, hotspot analysis, mean center, and standard deviation ellipse were used to examine the changing distribution of crime across 20 years. Based on 3900 reports of violent crime, our analyses suggest that the center of the gravity of crime changed over the years, spilling over to indigenous peoples’ landscapes. An examination of murder, where firearms and bladed weapons were the weapons of choice, suggests that these weapons moved beyond the coastal zone. The movement of weapons away from the coast raises concerns for the security of indigenous peoples and their associated wildlife. Our analysis suggests that policing measures should seek to extend towards Amerindian landscapes, and this is perhaps indicative of Latin American states with demographics similar to Guyana’s.
User Preferences on Route Instruction Types for Mobile Indoor Route Guidance
Authors: De Cock Laure , Ooms Kristien , Van de Weghe Nico , Vanhaeren Nina , De Maeyer Philippe
Published: October 2019

Adaptive mobile wayfinding systems are being developed to ease wayfinding in the indoor environment. They present wayfinding information to the user, which is adapted to the context. Wayfinding information can be communicated by using different types of route instructions, such as text, photos, videos, symbols or a combination thereof. The need for a different type of route instruction may vary at decision points, for example because of its complexity. Furthermore, these needs may be different for different user characteristics (e.g., age, gender, level of education). To determine this need for information, an online survey has been executed where participants rated 10 different route instruction types at several decision points in a case study building. Results show that the types with additional text were preferred over those without text. The photo instructions, combined with text, generally received the highest ratings, especially from first-time visitors. 3D simulations were appreciated at complex decision points and by younger people. When text (with symbols) is considered as a route instruction type, it is best used for the start or end instruction.
99mTc Labelling Strategies for the Development of Potential Nitroimidazolic Hypoxia Imaging Agents
Authors: Giglio Javier , Rey Ana
Published: October 2019

Technetium-99m has a rich coordination chemistry that offers many possibilities in terms of oxidation states and donor atom sets. Modifications in the structure of the technetium complexes could be very useful for fine tuning the physicochemical and biological properties of potential 99mTc radiopharmaceuticals. However, systematic study of the influence of the labelling strategy on the “in vitro” and “in vivo” behaviour is necessary for a rational design of radiopharmaceuticals. Herein we present a review of the influence of the Tc complexes’ molecular structure on the biodistribution and the interaction with the biological target of potential nitroimidazolic hypoxia imaging radiopharmaceuticals presented in the literature from 2010 to the present. Comparison with the gold standard [18F]Fluoromisonidazole (FMISO) is also presented.
Comparison of Orthognathic Surgery Outcomes Between Patients With and Without Underlying High-Risk Conditions: A Multidisciplinary Team-Based Approach and Practical Guidelines
Authors: Chou Pang-Yun , Denadai Rafael , Chen Chit , Pai Betty Chien-Jung , Hsu Kai-Hsiang , Chang Che-Tzu , Pascasio Dax , Lin Jennifer Ann-Jou , Chen Yu-Ray , Lo Lun-Jou
Published: October 2019

Orthognathic surgery (OGS) has been successfully adopted for managing a wide spectrum of skeletofacial deformities, but patients with underlying conditions have not been treated using OGS because of the relatively high risk of surgical anesthetic procedure-related complications. This study compared the OGS outcomes of patients with and without underlying high-risk conditions, which were managed using a comprehensive, multidisciplinary team-based OGS approach with condition-specific practical perioperative care guidelines. Data of surgical anesthetic outcomes (intraoperative blood loss, operative duration, need for prolonged intubation, reintubation, admission to an intensive care unit, length of hospital stay, and complications), facial esthetic outcomes (professional panel assessment), and patient-reported outcomes (FACE-Q social function, psychological well-being, and satisfaction with decision scales) of consecutive patients with underlying high-risk conditions (n = 30) treated between 2004 and 2017 were retrospectively collected. Patients without these underlying conditions (n = 30) treated during the same period were randomly selected for comparison. FACE-Q reports of 50 ethnicity-, sex-, and age-matched healthy individuals were obtained. The OGS-treated patients with and without underlying high-risk conditions differed significantly in their American Society of Anesthesiologists Physical Status (ASA-PS) classification (p < 0.05), Charlson comorbidity scores, and Elixhauser comorbidity scores. The two groups presented similar outcomes (all p > 0.05) for all assessed outcome parameters, except for intraoperative blood loss (p < 0.001; 974.3 ± 592.7 mL vs. 657.6 ± 355.0 mL). Comparisons with healthy individuals revealed no significant differences (p > 0.05). The patients with underlying high-risk conditions treated using a multidisciplinary team-based OGS approach and the patients without the conditions had similar OGS-related outcomes.
Regulation of c-Jun NH2-Terminal Kinase for Islet Transplantation
Authors: Noguchi Hirofumi
Published: October 2019

Islet transplantation has been demonstrated to provide superior glycemic control with reduced glucose lability and hypoglycemic events compared with standard insulin therapy. However, the insulin independence rate after islet transplantation from one donor pancreas has remained low. The low frequency of islet grafting is dependent on poor islet recovery from donors and early islet loss during the first hours following grafting. The reduction in islet mass during pancreas preservation, islet isolation, and islet transplantation leads to β-cell death by apoptosis and the prerecruitment of intracellular death signaling pathways, such as c-Jun NH2-terminal kinase (JNK), which is one of the stress groups of mitogen-activated protein kinases (MAPKs). In this review, we show some of the most recent contributions to the advancement of knowledge of the JNK pathway and several possibilities for the treatment of diabetes using JNK inhibitors.
An Association of Gut Microbiota with Different Phenotypes in Chinese Patients with Rheumatoid Arthritis
Authors: Chiang Hsin-I , Li Jian-Rong , Liu Chun-Chi , Liu Po-Yu , Chen Hsin-Hua , Chen Yi-Ming , Lan Joung-Liang , Chen Der-Yuan
Published: October 2019

We aimed to investigate the association of gut microbiota with disease activity, inflammatory parameters, and auto-antibodies profile in rheumatoid arthritis (RA). A total of 138 RA patients and 21 healthy controls (HC) were enrolled. Fecal samples were collected for bacterial DNA extraction and 16S ribosome (r)RNA sequencing, followed by analyses of gut microbiota composition. Serum levels of tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-17A were determined by using ELISA. Our results indicated that RA patients had lower diversity index, which reflects both evenness and richness of gut microbiota, compared to HC. The alpha-diversity was lower in anti-citrullinated peptide antibodies (ACPA)-positive patients than in HC. The phylum Verrucomicrobiae and genus Akkermansia were more abundant in patients compared to HC. There was increased relative abundance of Enterobacteriaceae as well as Klebsiella, and less abundance of Bifidobacterium in patients with high levels of TNF-α or IL-17A compared to those who had low levels of these cytokines. In addition, ACPA-positive patients had higher proportions of Blautia, Akkermansia, and Clostridiales than ACPA-negative patients. Gut dysbiosis in RA patients was presented as different microbial composition and its association with inflammatory parameters as well as ACPA seropositivity. These findings support the involvement of gut microbiota in RA pathogenesis.
Re-Differentiation Capacity of Human Chondrocytes in Vitro Following Electrical Stimulation with Capacitively Coupled Fields
Authors: Krueger Simone , Achilles Sophie , Zimmermann Julius , Tischer Thomas , Bader Rainer , Jonitz-Heincke Anika
Published: October 2019

Treatment of cartilage lesions remains a clinical challenge. Therefore, biophysical stimuli like electric fields seem to be a promising tool for chondrocytic differentiation and treatment of cartilage lesions. In this in vitro study, we evaluated the effects of low intensity capacitively coupled electric fields with an alternating voltage of 100 mVRMS (corresponds to 5.2 × 10−5 mV/cm) or 1 VRMS (corresponds to 5.2 × 10−4 mV/cm) with 1 kHz, on human chondrocytes derived from osteoarthritic (OA) and non-degenerative hyaline cartilage. A reduction of metabolic activity after electrical stimulation was more pronounced in non-degenerative cells. In contrast, DNA contents in OA cells were significantly decreased after electrical stimulation. A difference between 100 mVRMS and 1 VRMS was not detected. However, a voltage-dependent influence on gene and protein expression was observed. Both cell types showed increased synthesis rates of collagen (Col) II, glycosaminoglycans (GAG), and Col I protein following stimulation with 100 mVRMS, whereas this increase was clearly higher in OA cells. Our results demonstrated the sensitization of chondrocytes by alternating electric fields, especially at 100 mVRMS, which has an impact on chondrocytic differentiation capacity. However, analysis of further electrical stimulation parameters should be done to induce optimal hyaline characteristics of ex vivo expanded human chondrocytes.
Serum Level and Activity of Butylcholinesterase: A Biomarker for Post-Stroke Dementia
Authors: Chen Yi-Chun , Chou Wen-Hai , Fang Chiu-Ping , Liu Tung-Hsia , Tsou Hsiao-Hui , Wang Yun , Liu Yu-Li
Published: October 2019

Cholinergic neurotransmission regulates the immune response and inhibits cytokine release after stroke. The changes in the level/activity of blood cholinesterase (ChE) in patients with post-stroke dementia (PSD) are less known. This study aimed to examine post-stroke plasma acetylcholinesterase (AChE) and butylcholinesterase (BChE) and determine whether they are biomarkers for PSD. Thirty patients with PSD, 87 post-stroke patients without dementia (PSNoD), and 117 age- and gender-matched healthy controls were recruited. Missense genetic variants AChE rs1799806 and BChE rs1803274 were genotyped. The plasma AChE level did not differ between the PSD and PSNoD groups. However, BChE levels were significantly lower in the PSD than in the PSNoD group (3300.66 ± 515.35 vs 3855.74 ± 677.60 ng/mL, respectively; p = 0.0033). The activities of total ChE, BChE, and AChE were all lower in the PSD group (19,563.33 ± 4366.03, 7650.17 ± 1912.29, 11,913.17 ± 2992.42 mU/mL, respectively) than in the PSNoD group (23,579.08 ± 5251.55, 9077.72 ± 1727.28, and 14,501.36 ± 4197.17 mU/mL, respectively). When further adjusting for age and sex, significance remained in BChE level and activity and in total ChE activity. BChE rs1803274 was associated with reduced BChE activity, while AChE rs1799806 did not influence AChE activity. The level and activity of BChE, but not of AChE, were decreased in PSD patients and may therefore aid in PSD diagnosis.
High Myopia and Its Associated Factors in JPHC-NEXT Eye Study: A Cross-Sectional Observational Study
Authors: Mori Kiwako , Kurihara Toshihide , Uchino Miki , Torii Hidemasa , Kawashima Motoko , Sasaki Mariko , Ozawa Yoko , Yamagishi Kazumasa , Iso Hiroyasu , Sawada Norie , Tsugane Shoichiro , Yuki Kenya , Tsubota Kazuo
Published: October 2019

The increasing prevalence of high myopia has been noted. We investigated the epidemiological characteristics and the related factors of high myopia in a Japanese adult population. Japan Public Health Center-Based Prospective Study for the Next Generation (JPHC-NEXT) Eye Study was performed in Chikusei-city, a rural area in mid-east Japan, between 2013 and 2015. A cross-sectional observational analysis was conducted to investigate prevalence and related factors of high myopia. A total of 6101 participants aged ≥40 years without a history of ocular surgeries was included. High myopia was defined as a spherical equivalent refraction of ≤−6.00 diopters according to the American Academy of Ophthalmology. Potential high myopia-related factors included intraocular pressure (IOP), corneal structure, corneal endothelial cell density, age, height, body mass index, heart rate, blood pressure, biochemical profile, and current history of systemic and ocular disorders. The odds ratios of high myopia were estimated using the logistic regression models adjusted for the associated factors. The prevalence of high myopia was 3.8% in males and 5.9% in females with a significant difference. Age was inversely associated, IOP was positively associated, and none of other factors were associated with high myopia in both sexes. In conclusion, only age and IOP were associated with high myopia in this community-based sample.
The Predictive Accuracy of the General Movement Assessment for Cerebral Palsy: A Prospective, Observational Study of High-Risk Infants in a Clinical Follow-Up Setting
Authors: Støen Ragnhild , Boswell Lynn , de Regnier Raye-Ann , Fjørtoft Toril , Gaebler-Spira Deborah , Ihlen Espen , Labori Cathrine , Loennecken Marianne , Msall Michael , Möinichen Unn Inger , Peyton Colleen , Russow Annamarie , Schreiber Michael D. , Silberg Inger Elisabeth , Songstad Nils Thomas , Vågen Randi , Øberg Gunn Kristin , Adde Lars
Published: October 2019

Background: Early prediction of cerebral palsy (CP) using the General Movement Assessment (GMA) during the fidgety movements (FM) period has been recommended as standard of care in high-risk infants. The aim of this study was to determine the accuracy of GMA, alone or in combination with neonatal imaging, in predicting cerebral palsy (CP). Methods: Infants with increased risk of perinatal brain injury were prospectively enrolled from 2009–2014 in this multi-center, observational study. FM were classified by two certified GMA observers blinded to the clinical history. Abnormal GMA was defined as absent or sporadic FM. CP-status was determined by clinicians unaware of GMA results. Results: Of 450 infants enrolled, 405 had scorable video and follow-up data until at least 18–24 months. CP was confirmed in 42 (10.4%) children at mean age 3 years 1 month. Sensitivity, specificity, positive and negative predictive values, and accuracy of absent/sporadic FM for CP were 76.2, 82.4, 33.3, 96.8, and 81.7%, respectively. Only three (8.1%) of 37 infants with sporadic FM developed CP. The highest accuracy (95.3%) was achieved by a combination of absent FM and abnormal neonatal imaging. Conclusion: In infants with a broad range of neonatal risk factors, accuracy of early CP prediction was lower for GMA than previously reported but increased when combined with neonatal imaging. Sporadic FM did not predict CP in this study.
Investigation of the Influence of Aging on the Lubricity of Metalworking Fluids by Means of Design of Experiment
Authors: Seidel Benedikt , Meyer Daniel
Published: October 2019

The influence of complex aging processes in water-miscible metalworking fluids on process performance is of high relevance for the metalworking industry. Because of the highly dynamic interactions in the complex “metalworking fluid” ecosystem, a distinct correlation between the aging process and the performance of the fluid in metalworking processes is hardly possible. Consequences of the aging process on physical, chemical, and biological properties of the fluid include aspects such as the decrease of the pH value, the increase of the droplet size in emulsions, the presence of bacterial cells, or the modification of the metalworking fluid composition. In the presented work, the influences of these aging aspects on the lubricity of metalworking fluids were investigated individually. A test series has been carried out, which was planned with a design of experiments method, to investigate interactions between the aging aspects regarding lubricity. In addition, the results enabled the development of an empirical regression model, which allowed an integrated description of the influence of the relevant aging aspects.
LIPSS Structures Induced on Graphene-Polystyrene Composite
Authors: Fajstavr Dominik , Neznalová Klára , Švorčík Václav , Slepička Petr
Published: October 2019

A laser induced periodic surface structure (LIPSS) on graphene doped polystyrene was prepared by the means of a krypton fluoride (KrF) laser with the wavelength of 248 nm and precisely desired physico-chemical properties were obtained for the structure. Surface morphology after laser modification of polystyrene (PS) doped with graphene nanoplatelets (GNP) was studied. Laser fluence values of modifying laser light varied between 0–40 mJ·cm−2 and were used on polymeric PS substrates doped with 10, 20, 30, and 40 wt. % of GNP. GNP were incorporated into PS substrate with the solvent casting method and further laser modification was achieved with the same amount of laser pulses of 6000. Formed nanostructures with a periodic pattern were examined by atomic force microscopy (AFM). The morphology was also studied with scanning electron microscopy SEM. Laser irradiation resulted in changes of chemical composition on the PS surface, such as growth of oxygen concentration. This was confirmed with energy-dispersive X-ray spectroscopy (EDS).
The Development of Nanoalumina-Based Cement Mortars for Overlay Applications in Concrete Floors
Authors: Szymanowski Jacek , Sadowski Łukasz
Published: October 2019

This article focuses on the development of nanoalumina-based cement mortars for overlay applications in concrete floors. It focuses on the effect of applying aluminum oxide (Al2O3) nanopowder to the cement mortar used to make the overlay, on the adhesion of this overlay to concrete substrate and on its functional properties. It was claimed that the addition of 0.5% of Al2O3 nanopowder has a positive effect on the adhesion of the cement mortar used to make the overlay to the substrate made of concrete. The prior studies performed using scanning electron microscopy (SEM) confirmed that the reason for the improvement in adhesion is the fact that cement mortar used to make the overlay with the addition of 0.5% of Al2O3 nanopowder is less porous than the reference mortar within the interphase. The article concurs that the most favorable results, in terms of lower abrasion resistance and higher subsurface tensile strength of the cement mortar used to make the overlay, are mainly brought about by adding 0.5% of Al2O3 nanopowder.
Simulated and Experimental Research of Multi-Band Acoustic Metamaterial with a Single Resonant Structure
Authors: Chen Huaijun , Ding Changlin
Published: October 2019

We present a multi-band acoustic metamaterial (AMM) with a single structural unit of a nested split hollow sphere (NSHS). The transmissions of the NSHS-AMM from the simulation and experiment revealed two dips which were attributed to local coupling resonance. Using the retrieval method from the experimental data, we calculated the effective modulus of the NSHS-AMM and found it to be negative near the bands of the two dips. The AMM with a negative modulus can be easily tuned due to the coupling effect in the NSHS. The two dips can be simultaneously tuned by changing the diameter and the direction angle of the split holes of the interior and exterior split hollow sphere (SHS) in the NSHS. We designed a three-nested SHS-AMM with a negative modulus in three bands. Given the obvious local coupling resonance in the NSHS, such NSHS-AMMs may provide a viable path for the design of broadband AMMs or acoustic metasurfaces.
Junction Characterization in a Functionally Graded Aluminum Part
Authors: Fracchia Elisa , Gobber Federico Simone , Rosso Mario , Actis Grande Marco , Bidulská Jana , Bidulský Róbert
Published: October 2019

Aluminum alloys are widely used to produce automotive components, thanks to their great mechanical properties–to–density ratio. Engine components such as pistons are conventionally produced by casting of Al–Si eutectic alloys (Silumin alloys) such as EN AC 48000. Due to the harsh working conditions and the lower ductility if compared to aluminum–silicon alloys with lower silicon content, pistons made of this alloy are prone to fatigue failures in the skirt region. In order to overcome such limits, the use of a Functionally Graded Material (FGM) in the production of a piston is proposed. The adoption of a functionally graded architecture can maximize the properties of the component in specific areas. A higher level of thermal resistance in the crown of the piston can be achieved with EN AC 48000 (AlSi12CuNiMg), while higher elongation at rupture in the skirt region would be conferred by an EN AC 42100 (AlSi9Mg0.3). The FGM properties are strictly related to the metallurgical bonding between the alloys as well as to the presence of intermetallic phases in the alloys junction. In the present article, the characterization of gravity casted FGM samples based on Al–Si alloys with respect to microstructure and mechanical testing is presented, with a specific focus on the characterization by impact testing of the joint between the two alloys.
Impact of Basalt Filler and Ceramizable Additives on the Toxicity of Gaseous Products Emitted from Thermal Decomposition of Silicone Rubber Composites
Authors: Rybiński Przemysław , Syrek Bartłomiej , Żukowski Witold , Bradło Dariusz
Published: October 2019

The article illustrates the impact of basalt filler in the form of flakes and fibres on the toxicity of gaseous products that formed during the thermal decomposition of silicone rubber composites. The values of specific emissions of gases were determined with the help of the IR spectroscopy and further applied to calculate the toxicometric index. The presented method of measuring the concentrations of gaseous products resulting from thermal decomposition consists in the application of a fluidised bed reactor, which makes it possible to conduct the decomposition of a sample at a precisely assumed temperature value and imitate the conditions of a real fire. At a temperature lower than 700 °C, the gases resulting from the thermal decomposition of composites are particularly toxic due to the presence of significant concentrations of formaldehyde that does not undergo oxidation to more stable inorganic products. At a temperature of 600 °C the toxicity of gases for the samples with ceramizable additives and without them was similar. In the first case, there appeared to be a positive synergistic effect of mineral and basalt additives, and the basalt additives themselves increased the toxicity of gases. At higher temperatures of decomposition, the exponentially increasing rate of the oxidation reaction in the gaseous phase results in the lack of significant differences between the toxicity of gases for the samples with and without basalt additives. The toxicometric index value at temperatures of 700 °C and 800 °C was by one or two orders of magnitude higher, respectively, than the one that was observed in the temperature range of 500–600 °C, as inorganic components appear in the place of formaldehyde.
Experimental and Numerical Investigations on the Thermomechanical Behavior of 304 Stainless Steel/Q345R Composite Plate Weld Joint
Authors: Hu Xiaodong , Yang Yicheng , Song Ming
Published: October 2019

In this study, the welding process of 304 stainless steel/Q345R low alloy steel composite plate is modeled by experimental and finite element methods to study the complex thermomechanical behavior. The residual stress and microstructure evolution of composite plate in the welding process are also investigated. The welding thermal cycle curve and residual stress distribution at the joint are obtained by using thermocouple and blind-hole methods. Optical microscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy were used to investigate the evolution of microstructure, morphology, and element diffusion of the joint. The results show that the maximum von Mises welding residual stress is 312 MPa, which is located in the bottom of the start point of the weld zone. The residual stress gradually decreases and tends to be stable along the direction from the weld to the base metal. In addition, a residual stress discontinuity is found at the interface between the bimetal. It is also found that the closer it is to the weld joint, the more uniform is the austenite distribution and the smaller are the grain sizes.
Application of Natural Plant Fibers in Cement-Based Composites and the Influence on Mechanical Properties and Mass Transport
Authors: Zhao Kaiyue , Xue Shanbin , Zhang Peng , Tian Yupeng , Li Peibing
Published: October 2019

Recently, there is ongoing interest in the use of natural plant fibers as alternatives for conventional reinforcements in cementitious composites. The use of natural plant fibers makes engineering work more sustainable, since they are renewable, biodegradable, energy-efficient, and non-toxic raw materials. In this contribution, a comprehensive experimental program was undertaken to determine the influence of pineapple leaf fiber and ramie fiber on the mechanical properties and mass transport of cement-based composites. The compressive strength, tensile strength, modulus of elasticity, modulus of rupture, fracture energy, flexural toughness, coefficient of capillary water absorption, and chloride diffusion were measured. Natural plant fiber-reinforced cement-based composites (NPFRCCs) containing pineapple leaf fiber and ramie fiber, as compared to the plain control, exhibited a slight reduction in compressive strength and a considerable improvement in tensile strength, modulus of elasticity, modulus of rupture, and flexural toughness; the enhancement was remarkable with a higher fiber content. The coefficient of capillary absorption and chloride diffusion of NPFRCCs were significantly larger than the plain control, and the difference was evident with the increase in fiber content. The present study suggests that the specimen with 2% pineapple leaf fiber content can be used in normal environments due to its superior mechanical properties. However, one should be careful when using the material in marine environments.
Three-Dimensional Evaluation on Accuracy of Conventional and Milled Gypsum Models and 3D Printed Photopolymer Models
Authors: Choi Jae-Won , Ahn Jong-Ju , Son Keunbada , Huh Jung-Bo
Published: October 2019

The aim of this study was to evaluate the accuracy of dental models fabricated by conventional, milling, and three-dimensional (3D) printing methods. A reference model with inlay, single crown, and three-unit fixed dental prostheses (FDP) preparations was prepared. Conventional gypsum models (CON) were manufactured from the conventional method. Digital impressions were obtained by intraoral scanner, which were converted into physical models such as milled gypsum models (MIL), stereolithography (SLA), and digital light processing (DLP) 3D printed photopolymer models (S3P and D3P). Models were extracted as standard triangulated language (STL) data by reference scanner. All STL data were superimposed by 3D analysis software and quantitative and qualitative analysis was performed using root mean square (RMS) values and color difference map. Statistical analyses were performed using the Kruskal–Wallis test and Mann–Whitney U test with Bonferroni’s correction. For full arch, the RMS value of trueness and precision in CON was significantly smaller than in the other groups (p < 0.05/6 = 0.008), and there was no significant difference between S3P and D3P (p > 0.05/6 = 0.008). On the other hand, the RMS value of trueness in CON was significantly smaller than in the other groups for all prepared teeth (p < 0.05/6 = 0.008), and there was no significant difference between MIL and S3P (p > 0.05/6 = 0.008). In conclusion, conventional gypsum models showed better accuracy than digitally milled and 3D printed models.
Spinodal Decomposition and Mechanical Response of a TiZrNbTa High-Entropy Alloy
Authors: Liu Tai-You , Huang Jacob C. , Chuang Wen-Shuo , Chou Hung-Sheng , Wei Jui-Yu , Chao Chih-Yeh , Liao Yu-Chin , Jang Jason S.C.
Published: October 2019

In this study, the effects of spinodal decomposition on the microstructures and mechanical properties of a TiZrNbTa alloy are investigated. The as-cast TiZrNbTa alloy possesses dual phases of TiZr-rich inter-dendrite (ID) and NbTa-rich dendrite (DR) domains, both of which have a body-centered cubic (BCC) structure. In the DRs of the as-cast alloy, the α and ω precipitates are found to be uniformly distributed. After homogenization at 1100 °C for 24 h followed by water quenching, spinodal decomposition occurs and an interconnected structure with a wavelength of 20 nm is formed. The α and ω precipitates remained in the structure. Such a fine spinodal structure strengthens the alloy effectively. Detailed strengthening calculations were conducted in order to estimate the strengthening contributions from the α and ω precipitates, as well as the spinodal decomposition microstructure.
A Note on the Generalized Relativistic Diffusion Equation
Authors: Beghin Luisa , Garra Roberto
Published: October 2019

We study here a generalization of the time-fractional relativistic diffusion equation based on the application of Caputo fractional derivatives of a function with respect to another function. We find the Fourier transform of the fundamental solution and discuss the probabilistic meaning of the results obtained in relation to the time-scaled fractional relativistic stable process. We briefly consider also the application of fractional derivatives of a function with respect to another function in order to generalize fractional Riesz-Bessel equations, suggesting their stochastic meaning.
Directed Strongly Regular Cayley Graphs over Metacyclic Groups of Order 4n
Authors: Cheng Tao , Feng Lihua , Liu Weijun
Published: October 2019

We construct several new families of directed strongly regular Cayley graphs (DSRCGs) over the metacyclic group M 4 n = ⟨ a , b | a n = b 4 = 1 , b − 1 a b = a − 1 ⟩ , some of which generalize those earlier constructions. For a prime p and a positive integer α > 1 , for some cases, we characterize the DSRCGs over M 4 p α .
Identifying Phlorofucofuroeckol-A as a Dual Inhibitor of Amyloid-β25-35 Self-Aggregation and Insulin Glycation: Elucidation of the Molecular Mechanism of Action
Authors: Seong Su Hui , Paudel Pradeep , Jung Hyun Ah , Choi Jae Sue
Published: October 2019

Both amyloid-β (Aβ) and insulin are amyloidogenic peptides, and they play a critical role in Alzheimer’s disease (AD) and type-2 diabetes (T2D). Misfolded or aggregated Aβ and glycated insulin are commonly found in AD and T2D patients, respectively, and exhibit neurotoxicity and oxidative stress. The present study examined the anti-Aβ25-35 aggregation and anti-insulin glycation activities of five phlorotannins isolated from Ecklonia stolonifera. Thioflavin-T assay results suggest that eckol, dioxinodehydroeckol, dieckol, and phlorofucofuroeckol-A (PFFA) significantly inhibit Aβ25-35 self-assembly. Molecular docking and dynamic simulation analyses confirmed that these phlorotannins have a strong potential to interact with Aβ25-35 peptides and interrupt their self-assembly and conformational transformation, thereby inhibiting Aβ25-35 aggregation. In addition, PFFA dose-dependently inhibited d-ribose and d-glucose induced non-enzymatic insulin glycation. To understand the molecular mechanism for insulin glycation and its inhibition, we predicted the binding site of PFFA in insulin via computational analysis. Interestingly, PFFA strongly interacted with the Phe1 in insulin chain-B, and this interaction could block d-glucose access to the glycation site of insulin. Taken together, our novel findings suggest that phlorofucofuroeckol-A could be a new scaffold for AD treatment by inhibiting the formation of β-sheet rich structures in Aβ25-35 and advanced glycation end-products (AGEs) in insulin.
Study on the Nucleation and Growth of Pearlite Colony and Impact Toughness of Eutectoid Steel
Authors: Zhang Fei , Zhao Yonggang , Tan Yuanbiao , Ji Xuanming , Xiang Song
Published: October 2019

The relationship between microstructure parameters and mechanical properties was studied in this paper. The steel was heat-treated at different austenitizing temperatures to acquire varying microstructure. The results showed that austenite grain size increases with austenitizing temperature, while the pearlite colony size was relatively constant. The strength followed a Hall–Petch relationship with the austenite grain size, but the austenite grain size has nothing to do with the impact toughness. The control unit for determining the impact toughness of pearlitic steel is the pearlite colony size using a comparison method. Further studies have found that, in the hypoeutectoid steel and hypereutectoid steel, the pearlite colony size changes with the austenitizing temperature. However, when the eutectoid steel with a carbon content of 0.81% undergoes the isothermal transformation, the number of grain boundary precipitates is very few. There are many nucleation sites at the grain boundary. The pearlite colonies randomly nucleate at the grain boundaries and grow into the interior of the grains. Simultaneously, new pearlite colonies nucleate by the side of the existing pearlite colony. The intragranular pearlite colonies are also randomly nucleated. These nucleation sites increase the chance of the growing pearlite colonies colliding with each other, eventually resulting in a constant pearlite colony size.
Massive Sulfide Ores in the Iberian Pyrite Belt: Mineralogical and Textural Evolution
Authors: Almodóvar Gabriel R. , Yesares Lola , Sáez Reinaldo , Toscano Manuel , González Felipe , Pons Juan Manuel
Published: October 2019

The Iberian Pyrite Belt (IPB) is recognized as having one of the major concentrations of volcanogenic massive sulfide (VMS) deposits on Earth. Original resources of about 2000 Mt of massive sulfides have been reported in the province. Recent classifications have considered the IPB deposits as the bimodal siliciclastic subtype, although major differences can be recognized among them. The main ones concern the hosting rocks. To the north, volcanic and volcaniclastic depositional environments predominate, whereas to the south, black shale-hosted VMS prevail. The mineral composition is quite simple, with pyrite as the main mineral phase, and sphalerite, galena, and chalcopyrite as major components. A suite of minor minerals is also present, including arsenopyrite, tetrahedrite–tennantite, cobaltite, Sb–As–Bi sulfosalts, gold, and electrum. Common oxidized phases include magnetite, hematite, cassiterite, and barite. The spatial relationship between all these minerals provides a very rich textural framework. A careful textural analysis reported here leads to a general model for the genetic evolution of the IPB massive sulfides, including four main stages: (1) Sedimentary/diagenetic replacement process on hosting rocks; (2) sulfides recrystallization at rising temperature; (3) metal distillation and sulfides maturation related to late Sb-bearing hydrothermal fluids; and (4) metal remobilization associated with the Variscan tectonism. The proposed model can provide new tools for mineral exploration as well as for mining and metallurgy.