bluuebunny/crossref_metadata_2025 huggingface dataset:
The Outcome of Chemotherapy for Metastatic Extramammary Paget’s Disease
Authors: Hashimoto Hiroki , Kaku-Ito Yumiko , Furue Masutaka , Ito Takamichi
Published: February 2021

The efficacy and survival impact of conventional chemotherapies for metastatic extramammary Paget’s disease (EMPD) have not been fully elucidated. This study examined the long-term outcome of chemotherapy for this indication. We conducted a retrospective review of 21 patients with distant metastatic EMPD (14 patients treated with chemotherapy and 7 patients treated without chemotherapy). The response rate of chemotherapy and patient survival were statistically analyzed. Among the 14 patients treated with chemotherapy, 12, 1, and 1 patient received docetaxel, paclitaxel, and low-dose 5-fluorouracil plus cisplatin, respectively, as the first-line treatment. The response rate was 50.0% (7/14), and the disease control rate was 64.3% (9/14). The median progression-free survival (PFS) and overall survival (OS) were 16.8 and 27.9 months, respectively. Multivariate analyses revealed that chemotherapy was a significant factor for prolonged PFS (hazard ratio (HR) 0.22, p = 0.038) but not for OS (HR = 1.71, p = 0.54). Ten patients (71.4%) had severe (grade 3 or 4) hematological adverse events. Although conventional chemotherapy improved PFS, we failed to show a significantly improved OS. Considering the frequent adverse events of conventional chemotherapy, targeted therapy may become a mainstay for the treatment of metastatic EMPD.
Effect of TRPM8 and TRPA1 Polymorphisms on COPD Predisposition and Lung Function in COPD Patients
Authors: Naumov Denis E. , Kotova Olesya O. , Gassan Dina A. , Sugaylo Ivana Y. , Afanas’eva Evgeniya Y. , Sheludko Elizaveta G. , Perelman Juliy M.
Published: February 2021

Certain transient receptor potential (TRP) channels including TRPM8 and TRPA1 are widely expressed in the respiratory tract and have been shown to be the receptors of cigarette smoke and particulate matter—the main causative factors of chronic obstructive pulmonary disease (COPD). The aim of the study was to investigate the effect of TRPM8 and TRPA1 polymorphisms on COPD predisposition and lung function in COPD patients. The study enrolled 143 COPD patients and 104 smokers with post-bronchodilator forced expiratory volume in one second (FEV1)/forced vital capacity (FVC) > 70%. Lung function was measured by spirometry. TRPM8 and TRPA1 polymorphisms were genotyped by LATE-PCR. None of the polymorphisms significantly influenced COPD predisposition after correction for covariates and multiple testing. Among COPD patients, the TT genotype of TRPA1 rs7819749 was significantly associated with higher degree of bronchial obstruction. In addition, we established that carriers of the C allele of TRPM8 rs11562975 more commonly had post-bronchodilator FEV1 < 60% (OR 3.2, 95%CI (1.14–8.94), p = 0.03) and revealed the effect of TRPA1 rs959976 and TRPM8 rs17865682 on bronchodilator response in COPD. Thus, the obtained results suggest possible involvement of TRPM8 and TRPA1 in COPD pathogenesis, indicating the necessity to further investigate their functional role in this pathology.
Personalized Medicine Using Neuroimmunological Biomarkers in Depressive Disorders
Authors: Chi Suhyuk , Lee Moon-Soo
Published: February 2021

Major depressive disorder (MDD) is associated with increased suicidal risk and reduced productivity at work. Neuroimmunology, the study of the immune system and nervous system, provides further insight into the pathogenesis and outcome of MDD. Cytokines are the main modulators of neuroimmunology, and their levels are somewhat entangled in depressive disorders as they affect depressive symptoms and are affected by antidepressant treatment. The use of cytokine-derived medication as a treatment option for MDD is currently a topic of interest. Although not very promising, cytokines are also considered as possible prognostic or diagnostic markers for depression. The machine learning approach is a powerful tool for pattern recognition and has been used in psychiatry for finding useful patterns in data that have translational meaning and can be incorporated in daily clinical practice. This review focuses on the current knowledge of neuroimmunology and depression and the possible use of machine learning to widen our understanding of the topic.
Statin Therapy and the Risk of COVID-19: A Cohort Study of the National Health Insurance Service in South Korea
Authors: Oh Tak , Song In-Ae , Jeon Young-Tae
Published: February 2021

We aimed to investigate whether statin therapy is associated with the incidence of coronavirus disease 2019 (COVID-19) among the South Korean population. In addition, we examined whether statin therapy affects hospital mortality among COVID-19 patients. The National Health Insurance Service (NHIS)-COVID-19 database in South Korea was used for data extraction for this population-based cohort study. A total of 122,040 adult individuals, with 22,633 (18.5%) in the statin therapy group and 101,697 (91.5%) in the control group, were included in the analysis. Among them, 7780 (6.4%) individuals were diagnosed with COVID-19 and hospital mortality occurred in 251 (3.2%) COVID-19 cases. After propensity score matching, logistic regression analysis showed that the odds of developing COVID-19 were 35% lower in the statin therapy group than in the control group (odds ratio: 0.65, 95% confidence interval: 0.60 to 0.71; p < 0.001). Regarding hospital mortality among COVID-19 patients, the multivariable model indicated that there were no differences between the statin therapy and control groups (odds ratio: 0.74, 95% confidence interval: 0.52 to 1.05; p = 0.094). Statin therapy may have potential benefits for the prevention of COVID-19 in South Korea. However, we found that statin therapy does not affect the hospital mortality of patients who are diagnosed with COVID-19.
Integrating Patient-Specific Information into Logic Models of Complex Diseases: Application to Acute Myeloid Leukemia
Authors: Palma Alessandro , Iannuccelli Marta , Rozzo Ilaria , Licata Luana , Perfetto Livia , Massacci Giorgia , Castagnoli Luisa , Cesareni Gianni , Sacco Francesca
Published: February 2021

High throughput technologies such as deep sequencing and proteomics are increasingly becoming mainstream in clinical practice and support diagnosis and patient stratification. Developing computational models that recapitulate cell physiology and its perturbations in disease is a required step to help with the interpretation of results of high content experiments and to devise personalized treatments. As complete cell-models are difficult to achieve, given limited experimental information and insurmountable computational problems, approximate approaches should be considered. We present here a general approach to modeling complex diseases by embedding patient-specific genomics data into actionable logic models that take into account prior knowledge. We apply the strategy to acute myeloid leukemia (AML) and assemble a network of logical relationships linking most of the genes that are found frequently mutated in AML patients. We derive Boolean models from this network and we show that by priming the model with genomic data we can infer relevant patient-specific clinical features. Here we propose that the integration of literature-derived causal networks with patient-specific data should be explored to help bedside decisions.
Dynamic Effects of Material Production and Environmental Sustainability on Economic Vitality Indicators: A Panel VAR Approach
Authors: Leitão João , Ferreira Joaquim
Published: February 2021

This study analyzes the relationships and dynamics between material production, foreign direct investment (FDI), economic activity, carbon productivity, the stock market, and green tech, both in a global and European context, using panel vector autoregressive methodology (PVAR). The empirical evidence obtained for the Global Group reveals four significant and positive unidirectional causality relationships, where aggregate material production is the prominent variable. For the EU-15 group, six significant causality relationships were detected, among them three negative and three positive unidirectional relationships. The stock markets shock reveals to be the most dominant variable, despite FDI standing out as causing the greatest shock effect. Nevertheless, in the European context, limited evidence of dematerialization is detected. Economic recessions show a generally negative effect, which contrasts with the economic Kitchin cycles, which reveal the effect of a generally positive relationship.
Troubles with the Chf Loans in Croatia: The Story of a Case Still Waiting to Be Closed
Authors: Kundid Novokmet Ana
Published: February 2021

In numerous Central and Eastern European (CEE) countries, the global financial crisis as well as the unpegging of the foreign exchange rate of the Swiss franc (CHF) against the euro amplified the repayment troubles of households with the outstanding CHF-linked debt. In Croatia, the CHF loans were approved mainly as mortgages to unprotected and subprime household borrowers without sufficient credit capacity for long-term euro-linked loans, which also contained a possibility of an incremental interest rate change, i.e., the so-called administrative interest rate. This article aims to disclose the reasons behind the credit boom of these loans, the unsustainable CHF debt hardship that the household sector consequently faced, and how it was/could have been resolved, with the Croatian banking sector at the center of the research. Although the CHF case of Croatia has some specificities concerning the prudential regulation and government-sponsored loan conversion, the findings about the supply and demand determinants of the CHF credit boom, as well as a critical assessment of the Croatian government and central bank interventions, might be useful for timely noticing universal threats from the exotic currency-linked loans for the systemic risk and financial stability, and for minimizing the negative externalities from probable debt relief measures. Based on the descriptive and univariate statistics conducted on Bloomberg and the Croatian National Bank (CNB) data, it was found that interest rate differentials and carry trading behavior were the main reasons for the rapid CHF credit growth in Croatia. Nevertheless, according to the financial experts’ opinions obtained via a questionnaire survey, and the court verdicts reached since, the financial consumer protection when contracting these loans was severely violated, which implies that the central bank must enhance its consumer protection role. By adopting a single-country and holistic approach, this is the first paper that deals with the socioeconomic dynamic of the CHF credit default issues in Croatia, which might be interesting as a case study or for making comparison with other CEE countries that have been coping with negative consequences of Swiss francization.
Assessment and Spatial Planning for Peatland Conservation and Restoration: Europe’s Trans-Border Neman River Basin as a Case Study
Authors: Manton Michael , Makrickas Evaldas , Banaszuk Piotr , Kołos Aleksander , Kamocki Andrzej , Grygoruk Mateusz , Stachowicz Marta , Jarašius Leonas , Zableckis Nerijus , Sendžikaitė Jūratė , Peters Jan , Napreenko Maxim , Wichtmann Wendelin , Angelstam Per
Published: February 2021

Peatlands are the “kidneys” of river basins. However, intensification of agriculture and forestry in Europe has resulted in the degradation of peatlands and their biodiversity (i.e., species, habitats and processes in ecosystems), thus impairing water retention, nutrient filtration, and carbon capture. Restoration of peatlands requires assessment of patterns and processes, and spatial planning. To support strategic planning of protection, management, and restoration of peatlands, we assessed the conservation status of three peatland types within the trans-border Neman River basin. First, we compiled a spatial peatland database for the two EU and two non-EU countries involved. Second, we performed quantitative and qualitative gap analyses of fens, transitional mires, and raised bogs at national and sub-basin levels. Third, we identified priority areas for local peatland restoration using a local hotspot analysis. Nationally, the gap analysis showed that the protection of peatlands meets the Convention of Biological Diversity’s quantitative target of 17%. However, qualitative targets like representation and peatland qualities were not met in some regional sub-basins. This stresses that restoration of peatlands, especially fens, is required. This study provides an assessment methodology to support sub-basin-level spatial conservation planning that considers both quantitative and qualitative peatland properties. Finally, we highlight the need for developing and validating evidence-based performance targets for peatland patterns and processes and call for peatland restoration guided by social-ecological research and inter-sectoral collaborative governance.
Decoding the Street-Based Spatiality of Urban Gyms: Implications for Healthy City Planning
Authors: Jing Ying , Ma Ding , Liu Yaolin , Cui Jiaxing , Zhang Sheng , Chen Yiyun
Published: February 2021

Many cities face health issues that result from ineffective urban planning strategies. The chances of doing exercises in sportive venues implicate public health and citizen quality of life. With the advent of the geo-big data era, it is crucial to explore the spatial pattern of sports facilities to reflect urban health issues. This study aims to decode the street-based spatiality of gyms (one prevailing type of sportive venues) from a comprehensive perspective by both geometric methods (i.e., segment streets) and topological analytics in the context of complexity science (i.e., complex network derived from the topology of natural streets). We found that: (1) gyms are spatially clustered and distributed unevenly; (2) community-to-gym walkability fits the power-law with a heavy-tailed distribution at the 10-min and 20-min temporal scales; (3) the model for the street connectivity and the multi-distance reachability of gyms is with high polynomial fitting goodness. This article is conducive to strategies-making of healthy city planning and the further optimization of urban spatial structure.
Experiences and Development Impacts of Securing Land Rights at Scale in Developing Countries: Case Studies of China and Vietnam
Authors: Byamugisha Frank F. K.
Published: February 2021

This paper reviews experiences and development impacts of a selected number of developing countries in Asia and Africa that have used emerging land registration approaches to rapidly secure land rights at scale. Rapid and scalable registration is essential to eliminate a major backlog of the world’s unregistered land, which stands at about 70 percent. The objective of the review, based on secondary data, is to draw lessons that can help accelerate land registration across many countries. While the focus is on China and Vietnam, the findings are buttressed by those from previous reviews in Ethiopia and Rwanda. The registration approaches used in these four countries were found to be cost-reducing, fast, inclusive and scalable enough to secure land rights for all within one generation. They also had significant positive impacts on land tenure security and investment. In addition, they indirectly along with other economic reforms contributed to rapid economic growth and a reduction in extreme poverty. The experience from these Asian and African countries offers important lessons including the need for strong political commitment and to develop flexible legal and spatial frameworks that fit the purpose of land registration, instead of the rigid technical standards set by land professionals.
Oligodendroglial Heterogeneity in Neuropsychiatric Disease
Authors: Bøstrand Sunniva M. K. , Williams Anna
Published: February 2021

Oligodendroglia interact with neurons to support their health and maintain the normal functioning of the central nervous system (CNS). Human oligodendroglia are a highly heterogeneous population characterised by distinct developmental origins and regional differences, as well as variation in cellular states, as evidenced by recent analysis at single-nuclei resolution. Increasingly, there is evidence to suggest that the highly heterogeneous nature of oligodendroglia might underpin their role in a range of CNS disorders, including those with neuropsychiatric symptoms. Understanding the role of oligodendroglial heterogeneity in this group of disorders might pave the way for novel approaches to identify biomarkers and develop treatments.
Acceptance and Commitment Therapy (ACT) Improves Sleep Quality, Experiential Avoidance, and Emotion Regulation in Individuals with Insomnia—Results from a Randomized Interventional Study
Authors: Zakiei Ali , Khazaie Habibolah , Rostampour Masoumeh , Lemola Sakari , Esmaeili Maryam , Dürsteler Kenneth , Brühl Annette , Sadeghi-Bahmani Dena , Brand Serge
Published: February 2021

Insomnia is a common problem in the general population. To treat insomnia, medication therapies and insomnia-related cognitive-behavioral interventions are often applied. The aim of the present study was to investigate the influence of acceptance and commitment therapy (ACT) on sleep quality, dysfunctional sleep beliefs and attitudes, experiential avoidance, and acceptance of sleep problems in individuals with insomnia, compared to a control condition. A total of 35 participants with diagnosed insomnia (mean age: 41.46 years old; 62.9% females) were randomly assigned to the ACT intervention (weekly group therapy for 60–70 min) or to the active control condition (weekly group meetings for 60–70 min without interventional and psychotherapeutic character). At baseline and after eight weeks (end of the study), and again 12 weeks later at follow-up, participants completed self-rating questionnaires on sleep quality, dysfunctional beliefs and attitudes about sleep, emotion regulation, and experiential avoidance. Furthermore, participants in the intervention condition kept a weekly sleep log for eight consecutive weeks (micro-analysis). Every morning, participants completed the daily sleep log, which consisted of items regarding subjective sleep duration, sleep quality, and the feeling of being restored. Sleep quality, dysfunctional beliefs and attitudes towards sleep, emotion regulation, and experiential avoidance improved over time, but only in the ACT condition compared to the control condition. Improvements remained stable until follow-up. Improvements in experiential avoidance were related to a favorable change in sleep and cognitive-emotional processing. Micro-analyses showed that improvements occurred within the first three weeks of treatment. The pattern of results suggests that ACT appeared to have improved experiential avoidance, which in turn improved both sleep quality and sleep-related cognitive-emotional processes at longer-term in adults with insomnia.
Investigation of the Tribological Behavior of Mineral Lubricant Using Copper Oxide Nano Additives
Authors: Abdel-Rehim Ahmed A. , Akl Sayed , Elsoudy Sherif
Published: February 2021

In this study, tribological properties of custom formulated and stabilized nano lubricant are investigated. Spherical CuO nanoparticles are suspended in 20W-50 mineral base lubricant using Oleic Acid (OA) as a surfactant. Three different nano lubricant concentrations with 0.2, 0.5, and 1 wt.% were analyzed through ASTM G-99 pin-on-disc tribometer standardized test under boundary/mixed lubrication regimes. The generated friction and wear analyses confirm a consolidation of tribological properties with a reduction in friction coefficient in the range of 14.59–42.92%, compared with the base lubricant. Analysis of worn surfaces (SEM/EDX) as well as (AFM) was conducted. Combined hypotheses were proposed from the analysis of worn surfaces; these hypotheses suggested that CuO nanoparticles exhibit an integrated effect of two phenomenal lubrication mechanisms. Additionally, dispersion stability evaluation of the suspended nanoparticles was performed through Zeta potential, (FTIR), and sedimentation analyses. Stability results showed that steric stabilization is the dominating effect of the repulsive forces between nanoparticles, surpassing the electrostatic repulsive forces.
Porous Alumina Films Fabricated by Reduced Temperature Sulfuric Acid Anodizing: Morphology, Composition and Volumetric Growth
Authors: Poznyak Alexander , Pligovka Andrei , Laryn Tsimafei , Salerno Marco
Published: February 2021

The volumetric growth, composition, and morphology of porous alumina films fabricated by reduced temperature 280 K galvanostatic anodizing of aluminum foil in 0.4, 1.0, and 2.0 M aqueous sulfuric acid with 0.5–10 mA·cm−2 current densities were investigated. It appeared that an increase in the solution concentration from 0.4 to 2 M has no significant effect on the anodizing rate, but leads to an increase in the porous alumina film growth. The volumetric growth coefficient increases from 1.26 to 1.67 with increasing current density from 0.5 to 10 mA·cm−2 and decreases with increasing solution concentration from 0.4 to 2.0 M. In addition, in the anodized samples, metallic aluminum phases are identified, and a tendency towards a decrease in the aluminum content with an increase in solution concentration is observed. Anodizing at 0.5 mA·cm−2 in 2.0 M sulfuric acid leads to formation of a non-typical nanostructured porous alumina film, consisting of ordered hemispheres containing radially diverging pores.
High and Low-Temperature Performance Evaluation and Microanalysis of SMCSBS Compound-Modified Asphalt
Authors: Sun Yu , He Dongpo
Published: February 2021

The mixture of styreneic methyl copolymers (SMCs) normal temperature-modified asphalt and styrene-butadiene styrene block copolymer (SBS)-modified asphalt (SMCSBS) compound-modified asphalt was investigated in this study. The viscosity and temperature properties of compound modified asphalt (SMCSBS) were studied by Brookfield rotary viscosity test. Dynamic shear rheometer (DSR) and bending beam rheometer (BBR) were used to test SMCSBS compound modified asphalt with different SMC additions. Finally, the microstructure and physicochemical properties of SMCSBS were evaluated by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR), and the modification mechanism of the SMCSBS was studied. The results show that the viscosity of the compound-modified asphalt added with SMC is improved, which is conducive to improving its workability. With the increase of SMC content, the high-temperature performance of the compound modified asphalt firstly increases and then decreases with the increase of SMC content. When the content of SMC is 12%, its high-temperature performance is the best. Compared with SBS-modified asphalt, the SMCSBS has better low-temperature performance, and the creep stiffness S and creep rate m of the SMC with different content are better than that of SBS. Finally, the microcosmic characteristics show that the SMC can give full play to its characteristics and can be uniformly dispersed in SBS modified asphalt. SMC is essentially a surfactant, which can reduce the viscosity and construction temperature by changing the surface tension and surface free energy of asphalt molecules. The curing agent of epoxy resin is slowly cross-linked and cured after contacting with air to form a certain strength, thus improving the road performance of the asphalt mixture.
Evolution of the Shear Band in Cold-Rolling of Strip-Cast Fe-1.3% Si Non-Oriented Silicon Steel
Authors: Zhang Yuanxiang , Xia Yukun , Dun Hao , Wang Yang , Fang Feng , Zhang Yu , Zhang Jiecheng , Chen Qi , Zhai Kuangyu , Misra Raja Devesh Kumar
Published: February 2021

Cube texture and microstructural evolution of as-cast non-oriented silicon steel (1.3% Si) during cold rolling and annealing were studied. The results showed that the as-cast microstructure with grain size in the range of 100–500 μm had a weak texture. The strong orientation was mainly located at {100} and {110} planes. A significant content of shear-deformed grains oriented with {110}<110> were obtained by cold-rolling, and many regions oriented with Cube texture were distributed in the shear bands. During cold-rolling, the orientation of the shear-deformed microstructure tilted towards the {111}<112> orientation, while the matrix orientation retained {110}<110>. On further cold-rolling, the residual part of {110}<110> experienced shear deformation, forming more shear bands, strengthening the Cube orientation. During annealing, Cube orientation grains nucleated in the shear bands leading to strong Cube texture, and corresponding B50 was 1.83T/1.79T.
Polycrystalline Superalloy Membranes Produced by Load-Free Coarsening of Incoherent γ′-Precipitates: Microstructure Evolution and Mechanical Properties
Authors: Voelter Christian , Rösler Joachim
Published: February 2021

Nanoporous superalloy membranes are a functional extension of the use of nickel-based alloys. The material, which is usually used for high-temperature applications, consists mainly of the two phases γ and γ′. Through coarsening of the precipitates and thus forming of a bicontinuous γ/γ′ network, membranes can be produced by removing either of these phases. From the single-crystalline alloy CMSX-4, the bicontinuous network can be formed either thermo-mechanically by directional coarsening of coherent precipitates or by load-free coalescence of incoherent precipitates. Recent investigations have shown that membranes also can be produced from polycrystalline starting material in both ways. In this article, the process route for membranes by load-free coarsening of incoherent γ′ precipitates from a carbon-free version of the polycrystalline alloy Nimonic 115 is presented. This manufacturing method has the advantage of its simplicity and in comparison to single-crystalline membranes it can be realized in larger scales. We discuss the microstructure and show the mechanical properties by means of tensile tests. Despite the grain boundaries as a mechanical weak link, polycrystalline membranes show promising mechanical properties. Their strength even exceeds that of the single-crystalline membranes despite the significantly higher pore volume content.
Resistance of Soda Residue–Fly Ash Based Geopolymer Mortar to Acid and Sulfate Environments
Authors: Zhao Xianhui , Wang Haoyu , Zhou Boyu , Gao Han , Lin Yonghui
Published: February 2021

The early mechanical performances of low-calcium fly ash (FFA)-based geopolymer (FFA–GEO) mortar can be enhanced by soda residue (SR). However, the resistance of SR–FFA–GEO mortar to acid or sulfate environments is unclear, owing to the various inorganic calcium salts in SR. The aim of this study was to investigate the long-term mechanical strengths of up to 360 d and evaluate the resistance of SR–FFA–GEO mortar to 5% HCl and 5% Na2SO4 environments through the losses in compressive strength and mass. Scanning Electron Microscopy (SEM), Energy-Dispersive Spectroscopy (EDS) and Fourier Transform Infrared Spectrometer (FTIR) experiments were conducted for the SR–FFA–GEO mortars, both before and after chemical attack, to clarify the attack mechanism. The results show that the resistances of the SR–FFA–GEO mortar with 20% SR (namely M10) to 5% HCl and 5% Na2SO4 environments are superior to those of cement mortar. The environmental HCl reacts with the calcites in SR to produce CaCl2, CO2 and H2O to form more pores under HCl attack, and the environmental Na+ cations from Na2SO4 go into Si-O-Al network structure, to further enhance the strength of mortar under Na2SO4 attack. These results provide the experimental basis for the durability optimization of SR–FFA–GEO mortars.
W + Cu and W + Ni Composites and FGMs Prepared by Plasma Transferred Arc Cladding
Authors: Matějíček Jiří , Antoš Jakub , Rohan Pavel
Published: February 2021

Tungsten-based materials are the most prospective candidates for plasma-facing components of future fusion devices, such as DEMO. W-based composites and graded layers can serve as stress-relieving interlayers for the joints between plasma-facing armor and the cooling or structural parts. Coating/cladding techniques offer the advantages of eliminating the joining step and the ability to coat large areas, even on nonplanar shapes. In this work, W + Cu and W + Ni composites were prepared by pulsed plasma transferred arc (PTA) cladding on several different substrates. Optimization of the process was carried out with respect to powder mixture composition and process parameters like arc current, plasma gas composition, and traverse velocity. Dense claddings of several millimeters thickness and various W content were achieved. Moreover, multilayers with W content gradually varying from 47 to 92% were formed. The structure, compositional profiles, and thermal properties of the claddings were characterized.
Effect of Moisture Distribution on Velocity and Waveform of Ultrasonic-Wave Propagation in Mortar
Authors: Okazaki Shinichiro , Iwase Hiroma , Nakagawa Hiroyuki , Yoshida Hidenori , Hinei Ryosuke
Published: February 2021

Considering that the ultrasonic method is applied for the quality evaluation of concrete, this study experimentally and numerically investigates the effect of inhomogeneity caused by changes in the moisture content of concrete on ultrasonic wave propagation. The experimental results demonstrate that the propagation velocity and amplitude of the ultrasonic wave vary for different moisture content distributions in the specimens. In the analytical study, the characteristics obtained experimentally are reproduced by modeling a system in which the moisture content varies between the surface layer and interior of concrete.
Between-the-Holes Cryogenic Cooling of the Tool in Hole-Making of Ti-6Al-4V and CFRP
Authors: Iqbal Asif , Zhao Guolong , Zaini Juliana , Gupta Munish Kumar , Jamil Muhammad , He Ning , Nauman Malik Muhammad , Mikolajczyk Tadeusz , Pimenov Danil Yurievich
Published: February 2021

Lightweight materials are finding plentiful applications in various engineering sectors due to their high strength-to-weight ratios. Hole-making is an inevitable requirement for their structural applications, which is often marred by thermal damages of the drill causing unacceptable shortening of tool life. Efficient cooling of the tool is a prime requirement for enhancing the process viability. The current work presents a novel technique of cooling only the twist drill between drilling of holes with no effect of the applied cryogenic coolant transferred to the work material. The technique is applied in the drilling of two commonly used high-strength lightweight materials: carbon fibers reinforced polymer (CFRP) and an alloy of titanium (Ti-6Al-4V). The efficacy of the cooling approach is compared with those of conventionally applied continuous cryogenic cooling and no-cooling. The effectiveness is quantified in terms of tool wear, thrust force, hole quality, specific cutting energy, productivity, and consumption of the cryogenic fluid. The experimental work leads to a finding that between-the-holes cryogenic cooling possesses a rich potential in curbing tool wear, reducing thrust force and specific energy consumption, and improving hole quality in drilling of CFRP. Regarding the titanium alloy, it yields a much better surface finish and lesser consumption of specific cutting energy.
Influence of Compound Modification of Oil Sands De-Oiled Asphalt and Polyphosphoric Acid on High- and Low-Temperature Performance of Styrene-Butadiene-Styrene-Modified Asphalt
Authors: Pei Xiaoguang , Fan Weiyu
Published: February 2021

Oil sands de-oiled asphalt (OSDOA) has become a bottleneck for refineries due to its enormous production and huge landfill costs. Applying OSDOA as a modifier is an effective way to reduce environmental pollution and disposal cost. In this study, the influences of OSDOA and polyphosphoric acid (PPA) compound modification on styrene-butadiene-styrene (SBS)-modified binder were investigated. The high-temperature rutting resistance, low-temperature anti-crack performance and fatigue resistance were obtained by dynamic shear rheometer (DSR) and bending beam rheometer (BBR) test. Storage stability and microstructure were also investigated by storage test and Fourier-transform infrared (FTIR) spectroscopy. The results demonstrated that the compound modification of OSDOA/PPA dramatically enhanced the deformation resistance of SBS-modified binder and reduced its low-temperature cracking resistance. The anti-fatigue performance was also decreased. Moreover, the combined effect of OSDOA and PPA could produce composite modified asphalt with excellent storage stability, which was verified by desirable fluorescence images. Furthermore, both physical and chemical interactions coexisted during the OSDOA/PPA compound modification process. Consequently, the optimal doses of OSDOA and PPA were determined to be 10 wt% and 1.0 wt%, considering of the balance between high- and low-temperature characteristics and storage stability of composite modified asphalt.
Double Pulse Resistance Spot Welding of Dual Phase Steel: Parametric Study on Microstructure, Failure Mode and Low Dynamic Tensile Shear Properties
Authors: Soomro Imtiaz Ali , Pedapati Srinivasa Rao , Awang Mokhtar
Published: February 2021

Resistance spot welding (RSW) of dual phase (DP) steels is a challenging task due to formation of brittle martensitic structure in the fusion zone (FZ), resulting in a low energy capacity of the joint during high-rate loading. In the present study, in situ postweld heat treatment (PWHT) was carried out by employing a double pulse welding scheme with the aim of improving the mechanical performance of DP590 steel resistance spot weld joint. Taguchi method was used to optimize in situ PWHT parameters to obtain maximum peak load and failure energy. Experiments were designed based on orthogonal array (OA) L16. Mechanical performance was evaluated in terms of peak load and failure energy after performing low dynamic tensile shear (TS) test. Microstructural characterization was carried out using a scanning electron microscope (SEM). The results show that improvements of 17 and 86% in peak load and failure energy, respectively, were achieved in double-pulse welding (DPW) at optimum conditions compared to traditional single-pulse welding (SPW). The improvement in mechanical performance resulted from (i) enlargement of the FZ and (ii) improved weld toughness due to tempering of martensite in the FZ and subcritical heat affected zone (SCHAZ). These factors are influenced by heat input, which in turn depends upon in situ PWHT parameters.
Chitosan and Hydroxyapatite Based Biomaterials to Circumvent Periprosthetic Joint Infections
Authors: Costa-Pinto Ana Rita , Lemos Ana Luísa , Tavaria Freni Kekhasharú , Pintado Manuela
Published: February 2021

Every year, worldwide, millions of people suffering from joint pain undergo joint replacement. For most patients, joint arthroplasty reduces pain and improve function, though a small fraction will experience implant failure. One of the main reasons includes prosthetic joint infection (PJI), involving the prosthesis and adjacent tissues. Few microorganisms (MO) are required to inoculate the implant, resulting in the formation of a biofilm on its surface. Standard treatment includes not only removal of the infected prosthesis but also the elimination of necrotic bone fragments, local and/or systemic administration of antibiotics, and revision arthroplasty with a new prosthesis, immediately after the infection is cleared. Therefore, an alternative to the conventional therapeutics would be the incorporation of natural antimicrobial compounds into the prosthesis. Chitosan (Ch) is a potential valuable biomaterial presenting properties such as biocompatibility, biodegradability, low immunogenicity, wound healing ability, antimicrobial activity, and anti-inflammatory potential. Regarding its antimicrobial activity, Gram-negative and Gram-positive bacteria, as well as fungi are highly susceptible to chitosan. Calcium phosphate (CaP)-based materials are commonly utilized in orthopedic and dentistry for their excellent biocompatibility and bioactivity, particularly in the establishment of cohesive bone bonding that yields effective and rapid osteointegration. At present, the majority of CaP-based materials are synthetic, which conducts to the depletion of the natural resources of phosphorous in the future due to the extensive use of phosphate. CaP in the form of hydroxyapatite (HAp) may be extracted from natural sources as fish bones or scales, which are by-products of the fish food industry. Thus, this review aims to enlighten the fundamental characteristics of Ch and HAp biomaterials which makes them attractive to PJI prevention and bone regeneration, summarizing relevant studies with these biomaterials to the field.
Correlation between Microstructure and Magnetism in Ball-Milled SmCo5/α-Fe (5%wt. α-Fe) Nanocomposite Magnets
Authors: Bajorek Anna , Łopadczak Paweł , Prusik Krystian , Zubko Maciej
Published: February 2021

Magnetic nanocomposites SmCo5/α-Fe were synthesized mechanically by high-energy ball milling (HEBM) from SmCo5 and 5%wt. of α-Fe powders. The X-ray diffraction analysis reveals the hexagonal 1:5 phase as the main one accompanied by the cubic α-Fe phase and 2:17 rhombohedral as the secondary phase. The content of each detected phase is modified throughout the synthesis duration. A significant decrease in crystallite size with a simultaneous increase in lattice straining is observed. A simultaneous gradual reduction in particle size is noted from the microstructural analysis. Magnetic properties reveal non-linear modification of magnetic parameters associated with the strength of the exchange coupling induced by various duration times of mechanical synthesis. The highest value of the maximum energy product (BH)max at room temperature is estimated for samples milled for 1 and 6 h. The intermediate mixed-valence state of Sm ions is confirmed by electronic structure analysis. An increase in the Co magnetic moment versus the milling time is evidenced based on the performed fitting of the Co3s core level lines.
Manganese and Nickel Acetylacetonates as Curatives for Chloroprene Rubber Based on Heck’s Reaction
Authors: Dziemidkiewicz Anna , Maciejewska Magdalena
Published: February 2021

The commonly used curing system for chloroprene rubber (CR) is a combination of two metal oxides, such as magnesium oxide (MgO) and zinc oxide (ZnO). Application of MgO and ZnO enables to obtain a good balance between processability of rubber compounds and mechanical properties of the vulcanizates. Despite high activity in crosslinking reactions, ZnO is classified as ecotoxic to aquatic organisms, thus environmental legislation requires its quantity in technology to be limited. In our studies more environmentally friendly curing systems were applied, which enabled eliminating ZnO from CR compounds. These curing systems consisted of manganese acetylacetonate (Mn(acac)) or nickel acetylacetonate (Ni(acac)) and triethanolamine (TEOA) used as a base necessary to perform Heck’s reaction. Both metal acetylacetonates exhibited high activity in crosslinking reactions, which was confirmed by a great torque increment during rheometric measurements and high degree of elastomer crosslinking. The type of metal acetylacetonate and the amount of TEOA seemed to have less influence on the efficiency of the curing system than the filler used. Rubber compounds filled with carbon black (CB) were characterized by definitely shorter optimal vulcanization times and higher degree of crosslinking compared to CR composites filled with nanosized SiO2. Moreover, application of the proposed curing systems allowed to obtain CR vulcanizates with mechanical properties comparable with the benchmarks cured with metal oxides.
Temperature Influence on Formability and Microstructure of AZ31B during Electric Hot Temperature-Controlled Incremental Forming
Authors: Zhang Haoran , Chu Xingrong , Lin Shuxia , Bai Huawei , Sun Jiao
Published: February 2021

The straight groove test of AZ31B magnesium alloy sheet by electric hot temperature-controlled incremental sheet forming (ISF) was conducted at different temperatures. The temperature influence on fracture depth, deformation force and strain distribution was investigated. It was found that the limit depth and major strain increased as the temperature rose and that the forming force decreased correspondingly. Furthermore, the fracture behavior changed from brittle fracture to ductile fracture. Considering the formability and surface wear comprehensively, the optimized forming temperature was determined to be 300 °C. The microstructure of the groove specimen was analyzed and the dynamic recrystallization (DRX) was considered to be the reason for the improved formability. The degree of DRX depended on the temperature and degree of deformation, which resulted in non-uniform distribution of hardness within the cross section of the groove specimen.
Structure and Properties of Cast Ti-Al-Si Alloys
Authors: Knaislová Anna , Novák Pavel , Linhart Jiří , Szurman Ivo , Skotnicová Kateřina , Juřica Jan , Čegan Tomáš
Published: February 2021

Intermetallic compounds based on Ti-Al- (Si) are attractive materials with good thermal stability and low density. However, the production of these materials is quite complicated. Partially modified conventional methods of melting metallurgy are most often used due to availability, possible high productivity, and relatively low production costs. Therefore, some technologies for the production of intermetallics based on Ti-Al are currently available, but with certain disadvantages, which are caused by poor casting properties or extreme reactivity of the melt with crucibles. Some shortcomings can be eliminated by modifying the melting technology, which contributes to increasing the cost of the process. The work deals with the preparation of Ti-Al-Si intermetallic compounds with different contents of aluminum and silicon, which were produced by centrifugal casting in an induction vacuum furnace Linn Supercast-Titan. This process could contribute to the commercial use of these alloys in the future. For this research, the TiAl15Si15(in wt.%) alloy was selected, which represents a balanced ratio of aluminides and silicides in its structure, and the TiAl35Si5 alloy, which due to the lower silicon content allows better melting conditions, especially with regard to the melting temperature. This alloy was also investigated after HIP (“Hot Isostatic Pressing”) treatment.
Single-Stroke Attachment of Sheets to Tube Ends Made from Dissimilar Materials
Authors: Alves Luis M. , Reis Tiago J. , Afonso Rafael M. , Martins Paulo A.F.
Published: February 2021

This paper presents a new joining method by a forming process for attaching sheets to tube ends. The process consists of two different forming stages carried out sequentially in a single stroke. Firstly, the free tube end is flared by compression with a contoured die, then is squeezed (indented) against the sheet surface to create a mechanical interlocking. The new process is carried out at an ambient temperature and, in contrast to existing joining by forming operations based on tube expansion, it avoids seal welds, tube protrusions above the sheet surfaces, and machining of grooves on the sheet holes to obtain the form-fit joints. The paper starts by analyzing the process deformation mechanics and its main operating variables and finishes by presenting examples that demonstrate its effectiveness for attaching sheets to tube ends made from polyvinylchloride and aluminum. Experimental and numerical simulation work provides support to the presentation.
Anticancer Molecular Mechanism of Protocatechuic Acid Loaded on Folate Coated Functionalized Graphene Oxide Nanocomposite Delivery System in Human Hepatocellular Carcinoma
Authors: Buskaran Kalaivani , Bullo Saifullah , Hussein Mohd Zobir , Masarudin Mas Jaffri , Mohd Moklas Mohamad Aris , Fakurazi Sharida
Published: February 2021

Liver cancer is listed as the fifth-ranked cancer, responsible for 9.1% of all cancer deaths globally due to its assertive nature and poor survival rate. To overcome this obstacle, efforts have been made to ensure effective cancer therapy via nanotechnology utilization. Recent studies have shown that functionalized graphene oxide (GO)-loaded protocatechuic acid has shown some anticancer activities in both passive and active targeting. The nanocomposites’ physicochemical characterizations were conducted. A lactate dehydrogenase experiment was conducted to estimate the severity of cell damage. Subsequently, a clonogenic assay was carried out to examine the colony-forming ability during long-term exposure of the nanocomposites. The Annexin V/ propidium iodide analysis showed that nanocomposites induced late apoptosis in HepG2 cells. Following the intervention of nanocomposites, cell cycle arrest was ascertained at G2/M phase. There was depolarization of mitochondrial membrane potential and an upregulation of reactive oxygen species when HepG2 cells were induced by nanocomposites. Finally, the proteomic profiling array and quantitative reverse transcription polymerase chain reaction revealed the expression of pro-apoptotic and anti-apoptotic proteins induced by graphene oxide conjugated PEG loaded with protocatechuic acid drug folic acid coated nanocomposite (GOP–PCA–FA) in HepG2 cells. In conclusion, GOP–PCA–FA nanocomposites treated HepG2 cells exhibited significant anticancer activities with less toxicity compared to pristine protocatechuic acid and GOP–PCA nanocomposites, due to the utilization of a folic acid-targeting nanodrug delivery system.
Bending Strength of Wood Treated with Propolis Extract and Silicon Compounds
Authors: Woźniak Magdalena , Mania Przemysław , Roszyk Edward , Ratajczak Izabela
Published: February 2021

The modification of wood and its treatment with various preservatives may affect its mechanical properties, hence the knowledge of the character changes in wood caused by impregnation is of great importance. Therefore, the aim of the research was to determine the effect of impregnation, with the propolis-silane preparation (EEP-MPTMOS/TEOS) consisting of the propolis extract (EEP) and silicon compounds: 3-(trimethoxysilyl)propyl methacrylate (MPTMOS) and tetraethoxysilane (TEOS), on the bending strength of treated wood. Moreover, in the study wood treated with components of the propolis-silane formulation was used, namely 70% ethanol, the propolis extract, and silanes (MPTMOS/TEOS). In order to determine whether the impregnation of wood affects its long-term bending, creep tests were performed depending on the humidity. The impregnation of wood with the propolis extract and the propolis-silane preparation (EEP-MPTMOS/TEOS) contributed to the increase in modulus of rapture and work to maximum load values compared to the untreated wood. In dry wood condition, the wood treated with EEP and EEP-MPTMOS/TEOS was characterized by lower modulus of elasticity values than the control samples. In turn, in wet wood condition, wood treated with the propolis-silane preparation showed an increase in the MOE value. Moreover, the impregnation of wood had an influence on the wood creep process under bending loads. The treated wood was characterized by higher relative creep compliance than the untreated wood. The exception was the wood impregnated with EEP-MPTMOS/TEOS, which showed comparable relative creep compliance to the control samples. The presented results indicate that wood treated with a bio-friendly preparation based on propolis and silicon compounds can be used in various application and also in variable humidity conditions.