bluuebunny/crossref_metadata_2025 huggingface dataset:
Citrus Auraptene Induces Glial Cell Line-Derived Neurotrophic Factor in C6 Cells
Authors: Furukawa Yoshiko , Hara Ryu-ichi , Nakaya Makiko , Okuyama Satoshi , Sawamoto Atsushi , Nakajima Mitsunari
Published: January 2020

We previously demonstrated that auraptene (AUR), a natural coumarin derived from citrus plants, exerts anti-inflammatory effects in the brain, resulting in neuroprotection in some mouse models of brain disorders. The present study showed that treatment with AUR significantly increased the release of glial cell line-derived neurotrophic factor (GDNF), in a dose- and time-dependent manner, by rat C6 glioma cells, which release was associated with increased expression of GDNF mRNA. These results suggest that AUR acted as a neuroprotective agent in the brain via not only its anti-inflammatory action but also its induction of neurotrophic factor. We also showed that (1) the AUR-induced GDNF production was inhibited by U0126, a specific inhibitor of mitogen-activated protein kinase/extracellular signal-regulated kinase (ERK) 1/2, and by H89, a specific inhibitor of protein kinase A (PKA); and (2) AUR induced the phosphorylation of cAMP response element-binding protein (CREB), a transcription factor located within the nucleus. These results suggest that AUR-stimulated gdnf gene expression was up-regulated through the PKA/ERK/CREB pathway in C6 cells.
Lipopolysaccharide-Induced Matrix Metalloproteinase-9 Expression Associated with Cell Migration in Rat Brain Astrocytes
Authors: Yang Chien-Chung , Lin Chih-Chung , Hsiao Li-Der , Kuo Jing-Ming , Tseng Hui-Ching , Yang Chuen-Mao
Published: January 2020

Neuroinflammation is a landmark of neuroinflammatory and neurodegenerative diseases. Matrix metalloproteinase (MMP)-9, one member of MMPs, has been shown to contribute to the pathology of these brain diseases. Several experimental models have demonstrated that lipopolysaccharide (LPS) exerts a pathological role through Toll-like receptors (TLRs) in neuroinflammation and neurodegeneration. However, the mechanisms underlying LPS-induced MMP-9 expression in rat brain astrocytes (RBA-1) are not completely understood. Here, we applied pharmacological inhibitors and siRNA transfection to assess the levels of MMP-9 protein, mRNA, and promoter activity, as well as protein kinase phosphorylation in RBA-1 cells triggered by LPS. We found that LPS-induced expression of pro-form MMP-9 and cell migration were mediated through TLR4, proto-oncogene tyrosine-protein kinase (c-Src), proline-rich tyrosine kinase 2 (Pyk2), platelet-derived growth factor receptor (PDGFR), phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt), p38 mitogen-activated protein kinase (MAPK), and Jun amino-terminal kinase (JNK)1/2 signaling molecules in RBA-1 cells. In addition, LPS-stimulated binding of c-Jun to the MMP-9 promoter was confirmed by chromatin immunoprecipitation (ChIP) assay, which was blocked by pretreatment with c-Src inhibitor II, PF431396, AG1296, LY294002, Akt inhibitor VIII, p38 MAP kinase inhibitor VIII, SP600125, and tanshinone IIA. These results suggest that in RBA-1 cells, LPS activates a TLR4/c-Src/Pyk2/PDGFR/PI3K/Akt/p38 MAPK and JNK1/2 pathway, which in turn triggers activator protein 1 (AP-1) activation and ultimately induces MMP-9 expression and cell migration.
Regulation of the p53 Family Proteins by the Ubiquitin Proteasomal Pathway
Authors: Bang Scott , Kaur Sandeep , Kurokawa Manabu
Published: January 2020

The tumor suppressor p53 and its homologues, p63 and p73, play a pivotal role in the regulation of the DNA damage response, cellular homeostasis, development, aging, and metabolism. A number of mouse studies have shown that a genetic defect in the p53 family could lead to spontaneous tumor development, embryonic lethality, or severe tissue abnormality, indicating that the activity of the p53 family must be tightly regulated to maintain normal cellular functions. While the p53 family members are regulated at the level of gene expression as well as post-translational modification, they are also controlled at the level of protein stability through the ubiquitin proteasomal pathway. Over the last 20 years, many ubiquitin E3 ligases have been discovered that directly promote protein degradation of p53, p63, and p73 in vitro and in vivo. Here, we provide an overview of such E3 ligases and discuss their roles and functions.
Inflammation and Oxidative Stress in Chronic Kidney Disease—Potential Therapeutic Role of Minerals, Vitamins and Plant-Derived Metabolites
Authors: Rapa Shara Francesca , Di Iorio Biagio Raffaele , Campiglia Pietro , Heidland August , Marzocco Stefania
Published: January 2020

Chronic kidney disease (CKD) is a debilitating pathology with various causal factors, culminating in end stage renal disease (ESRD) requiring dialysis or kidney transplantation. The progression of CKD is closely associated with systemic inflammation and oxidative stress, which are responsible for the manifestation of numerous complications such as malnutrition, atherosclerosis, coronary artery calcification, heart failure, anemia and mineral and bone disorders, as well as enhanced cardiovascular mortality. In addition to conventional therapy with anti-inflammatory and antioxidative agents, growing evidence has indicated that certain minerals, vitamins and plant-derived metabolites exhibit beneficial effects in these disturbances. In the current work, we review the anti-inflammatory and antioxidant properties of various agents which could be of potential benefit in CKD/ESRD. However, the related studies were limited due to small sample sizes and short-term follow-up in many trials. Therefore, studies of several anti-inflammatory and antioxidant agents with long-term follow-ups are necessary.
Molecular Mapping and Candidate Gene Analysis for GA3 Responsive Short Internode in Watermelon (Citrullus lanatus)
Authors: Gebremeskel Haileslassie , Dou Junling , Li Bingbing , Zhao Shengjie , Muhammad Umer , Lu Xuqiang , He Nan , Liu Wenge
Published: January 2020

Plants with shorter internodes are suitable for high-density planting, lodging resistance and the preservation of land resources by improving yield per unit area. In this study, we identified a locus controlling the short internode trait in watermelon using Zhengzhouzigua (long internode) and Duan125 (short internode) as mapping parents. Genetic analysis indicated that F1 plants were consistent with long internode plants, which indicates that the long internode was dominant over the short internode. The observed F2 and BC1 individuals fitted the expected phenotypic segregation ratios of 3:1 and 1:1, respectively. The locus was mapped on chromosome 9 using a bulked segregant analysis approach. The region was narrowed down to 8.525 kb having only one putative gene, Cla015407, flanking by CAPS90 and CAPS91 markers, which encodes gibberellin 3β-hydroxylase (GA 3β-hydroxylase). The sequence alignment of the candidate gene between both parents revealed a 13 bp deletion in the short internode parent, which resulted in a truncated protein. Before GA3 application, significantly lower GA3 content and shorter cell length were obtained in the short internode plants. However, the highest GA3 content and significant increase in cell length were observed in the short internode plants after exogenous GA3 application. In the short internode plants, the expression level of the Cla015407 was threefold lower than the long internode plants in the stem tissue. In general, our results suggested that Cla015407 might be the candidate gene responsible for the short internode phenotype in watermelon and the phenotype is responsive to exogenous GA3 application.
The Temperature-Dependent Retention of Introns in GPI8 Transcripts Contributes to a Drooping and Fragile Shoot Phenotype in Rice
Authors: Zhao Bo , Tang Yongyan , Zhang Baocai , Wu Pingzhi , Li Meiru , Xu Xinlan , Wu Guojiang , Jiang Huawu , Chen Yaping
Published: January 2020

Attachment of glycosylphosphatidylinositols (GPIs) to the C-termini of proteins is one of the most common posttranslational modifications in eukaryotic cells. GPI8/PIG-K is the catalytic subunit of the GPI transamidase complex catalyzing the transfer en bloc GPI to proteins. In this study, a T-DNA insertional mutant of rice with temperature-dependent drooping and fragile (df) shoots phenotype was isolated. The insertion site of the T-DNA fragment was 879 bp downstream of the stop codon of the OsGPI8 gene, which caused introns retention in the gene transcripts, especially at higher temperatures. A complementation test confirmed that this change in the OsGPI8 transcripts was responsible for the mutant phenotype. Compared to control plants, internodes of the df mutant showed a thinner shell with a reduced cell number in the transverse direction, and an inhomogeneous secondary wall layer in bundle sheath cells, while many sclerenchyma cells at the tops of the main veins of df leaves were shrunken and their walls were thinner. The df plants also displayed a major reduction in cellulose and lignin content in both culms and leaves. Our data indicate that GPI anchor proteins play important roles in biosynthesis and accumulation of cell wall material, cell shape, and cell division in rice.
Lysophosphatidic Acid Upregulates Recepteur D’origine Nantais Expression and Cell Invasion via Egr-1, AP-1, and NF-κB Signaling in Bladder Carcinoma Cells
Authors: Khoi Pham Ngoc , Li Shinan , Thuan Ung Trong , Sah Dhiraj Kumar , Kang Taek Won , Nguyen Thi Thinh , Lian Sen , Xia Yong , Jung Young Do
Published: January 2020

Muscle invasive bladder carcinoma is a highly malignant cancer with a high mortality rate, due to its tendency to metastasize. The tyrosine kinase recepteur d’origine nantais (RON) promotes bladder carcinoma metastasis. Lysophosphatidic acid (LPA) is a phospholipid derivative, which acts as a signaling molecule to activate three high affinity G-protein coupled receptors, LPA1, LPA2, and LPA3. This in turn leads to cell proliferation and contributes to oncogenesis. However, little is known about the effects of LPA on invasive bladder cancer (IBC). In this study, we discovered that LPA upregulated RON expression, which in turn promoted cell invasion in bladder cancer T24 cells. As expected, we found that the LPA receptor was essential for the LPA induced increase in RON expression. More interestingly, we discovered that LPA induced RON expression via the MAPK (ERK1/2, JNK1/2), Egr-1, AP-1, and NF-κB signaling axes. These results provide experimental evidence and novel insights regarding bladder malignancy metastasis, which could be helpful for developing new therapeutic strategies for IBC treatment.
Stereocilia Rootlets: Actin-Based Structures That Are Essential for Structural Stability of the Hair Bundle
Authors: Pacentine Itallia , Chatterjee Paroma , Barr-Gillespie Peter G.
Published: January 2020

Sensory hair cells of the inner ear rely on the hair bundle, a cluster of actin-filled stereocilia, to transduce auditory and vestibular stimuli into electrical impulses. Because they are long and thin projections, stereocilia are most prone to damage at the point where they insert into the hair cell’s soma. Moreover, this is the site of stereocilia pivoting, the mechanical movement that induces transduction, which additionally weakens this area mechanically. To bolster this fragile area, hair cells construct a dense core called the rootlet at the base of each stereocilium, which extends down into the actin meshwork of the cuticular plate and firmly anchors the stereocilium. Rootlets are constructed with tightly packed actin filaments that extend from stereocilia actin filaments which are wrapped with TRIOBP; in addition, many other proteins contribute to the rootlet and its associated structures. Rootlets allow stereocilia to sustain innumerable deflections over their lifetimes and exemplify the unique manner in which sensory hair cells exploit actin and its associated proteins to carry out the function of mechanotransduction.
Mediation Analysis Supports a Causal Relationship between Maternal Hyperglycemia and Placental DNA Methylation Variations at the Leptin Gene Locus and Cord Blood Leptin Levels
Authors: Gagné-Ouellet Valérie , Breton Edith , Thibeault Kathrine , Fortin Carol-Ann , Cardenas Andres , Guérin Renée , Perron Patrice , Hivert Marie-France , Bouchard Luigi
Published: January 2020

Changes in fetal DNA methylation (DNAm) of the leptin (LEP) gene have been associated with exposure to maternal hyperglycemia, but their links with childhood obesity risk are still unclear. We investigated the association between maternal hyperglycemia, placental LEP DNAm (25 5′-C-phosphate-G-3′ (CpG) sites), neonatal leptinemia, and adiposity (i.e., BMI and skinfold thickness (ST) (subscapular (SS) + triceps (TR) skinfold measures, and the ratio of SS:TR) at 3-years-old, in 259 mother–child dyads, from Gen3G birth cohort. We conducted multivariate linear analyses adjusted for gestational age at birth, sex of the child, age at follow-up, and cellular heterogeneity. We assessed the causal role of DNAm in the association between maternal glycemia and childhood outcomes, using mediation analysis. We found three CpGs associated with neonatal leptinemia (p ≤ 0.002). Of these, cg05136031 and cg15758240 were also associated with BMI (β = −2.69, p = 0.05) and fat distribution (β = −0.581, p = 0.05) at 3-years-old, respectively. Maternal glycemia was associated with DNAm at cg15758240 (β = −0.01, p = 0.04) and neonatal leptinemia (β = 0.19, p = 0.004). DNAm levels at cg15758240 mediates 0.8% of the association between maternal glycemia and neonatal leptinemia (p < 0.001). Our results support that DNAm regulation of the leptin pathway in response to maternal glycemia might be involved in programming adiposity in childhood.
Focusing Schlieren Visualization of Transonic Turbine Tip-Leakage Flows
Authors: Passmann Maximilian , aus der Wiesche Stefan , Joos Franz
Published: January 2020

This paper presents a focusing schlieren system designed for the investigation of transonic turbine tip-leakage flows. In the first part, the functional principle and the design of the system are presented. Major design considerations and necessary trade-offs are discussed. The key optical properties, e.g., depth of focus, are verified by means of a simple bench test. In the second part, results of an idealized tip-clearance model as well as linear cascade tests at engine representative Reynolds and Mach numbers are presented and discussed. The focusing schlieren system, designed for minimum depth of focus, has been found to be well suited for the investigation of three-dimensional transonic flow fields in turbomachinery applications. The schlieren images show the origin and growth of the tip-leakage vortex on the blade suction side. A complex shock system was observed in the tip region, and the tip-leakage vortex was found to interact with the suction side part of the trailing edge shock system. The results indicate that transonic vortex shedding is suppressed in the tip region at an exit Mach number around M 2 , i s = 0.8.
Rectal Gland Chemistry, Volatile Emissions, and Antennal Responses of Male and Female Banana Fruit Fly, Bactrocera musae
Authors: Noushini Saeedeh , Perez Jeanneth , Park Soo Jean , Holgate Danielle , Jamie Ian , Jamie Joanne , Taylor Phillip
Published: January 2020

The banana fruit fly, Bactrocera musae (Tryon) (Diptera: Tephritidae), is an economically important pest endemic to Australia and mainland Papua New Guinea. The chemistry of its rectal glands, and the volatiles emitted during periods of sexual activity, has not been previously reported. Using gas chromatography–mass spectrometry (GC-MS), we find that male rectal glands contain ethyl butanoate, N-(3-methylbutyl) acetamide, ethyl laurate and ethyl myristate, with ethyl butanoate as the major compound in both rectal gland and headspace volatile emissions. Female rectal glands contain four major compounds, ethyl laurate, ethyl myristate, ethyl palmitate and (E,E)-2,8-dimethyl-1,7-dioxaspiro[5.5]undecane, as well as 11 minor compounds. For both male and female B. musae, all compounds found in the headspace were also present in the rectal gland extracts, suggesting that the rectal gland is the main source of the headspace volatiles. Gas chromatography–electroantennography (GC-EAD) of rectal gland extracts confirms that male antennae respond to male-produced ethyl laurate and female-produced (E,E)-2,8-dimethyl-1,7-dioxaspiro[5.5]undecane, while female antennae respond to male-produced ethyl butanoate but no female-produced compounds. This is an important step in understanding the volatiles involved in the chemical communication of B. musae, their functional significance, and potential application.
Stroke Prophylaxis in Patients with Atrial Fibrillation and End-Stage Renal Disease
Authors: van Zyl Martin , Abdullah Hafez M. , Noseworthy Peter A. , Siontis Konstantinos C.
Published: January 2020

Atrial fibrillation (AF) is an important comorbidity in patients with end-stage renal disease (ESRD) undergoing dialysis that portends increased health care utilization, morbidity, and mortality in this already high-risk population. Patients with ESRD have a particularly high stroke risk, which is further compounded by AF. However, the role of anticoagulation for stroke prophylaxis in ESRD and AF is debated. The ESRD population presents a unique challenge because of the combination of elevated stroke and bleeding risks. Warfarin has been traditionally used in this population, but it is associated with significant risks of minor and major bleeding, particularly intracranial, thus leading many clinicians to forgo anticoagulation altogether. When anticoagulation is prescribed, rates of adherence and persistence are poor, leaving many patients untreated. The direct oral anticoagulants (DOACs) may offer an alternative to warfarin in ESRD patients, but these agents have not been extensively studied in this population and uncertainties regarding comparative effectiveness (versus warfarin, each other, and no treatment) remain. In this review, we discuss the current evidence on the risk and benefits of anticoagulants in this challenging population and comparisons between warfarin and DOACs, and review future directions including options for non-pharmacologic stroke prevention.
Editorial for the Special Issue on “The Belt and Road-Risks and Financial Management Issues Faced by Enterprises’ Internationalization”
Authors: Shao Xue-Feng , Liu Wei , Yue Xiao-Guang
Published: January 2020

In recent years, deglobalization and protectionism have been prevalent in different regions of the world (Evenett 2019; Prashantham et al [...]
Advanced Simulation Tools Applied to Materials Development and Design Predictions
Authors: Correia José , De Jesus Abílio , Zhu Shun-Peng , Zhang Xiancheng , Hu Dianyin
Published: January 2020

This thematic issue on advanced simulation tools applied to materials development and design predictions gathers selected extended papers related to power generation systems, presented at the XIX International Colloquium on Mechanical Fatigue of Metals (ICMFM XIX) organized at University of Porto, Portugal, in 2018. Guest editors express special thanks to all contributors for the success of this special issue—authors, reviewers, and journal staff.
Size-Dependent Structural Properties of a High-Nb TiAl Alloy Powder
Authors: Liu Binglin , Wang Maosong , Du Yulei , Li Jingxiao
Published: January 2020

TiAl-based alloys are promising light weight structural materials for high temperature applications in the field of aerospace. Recently, fabrication technologies starting from powders including powder metallurgy and additive manufacturing have been developed to overcome the difficulties in the processing, machining and shaping of TiAl-based alloys. Spherical alloy powders with different particle size distributions are usually used in these fabrication techniques. The purpose of this study is to reveal the size-dependent structural properties of a high-Nb TiAl powder for these fabrication technologies starting from powders. A high-Nb TiAl pre-alloyed powder with nominal composition of Ti-48Al-2Cr-8Nb (at. %) was prepared by the electrode induction melting gas atomization (EIGA) method. The phase structure and morphology of the as-atomized powders were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The size-dependent structural changes of the as-atomized powders with different sizes were studied by differential scanning calorimetry (DSC) and in situ high temperature XRD. It was found that with decreasing the powder size, the content of the γ-TiAl phase decreases and the α2-Ti3Al phase increases. The α2-Ti3Al to γ-TiAl phase transformation was found in the temperature range of 600–770 °C. Based on the present work, the structural characteristics of TiAl powders are strongly dependent on their particle size, which should be considered in optimizing the process parameters of TiAl alloys fabricated from powders.
Parametric Formulae for Elastic Stress Concentration Factor at the Weld Toe of Distorted Butt-Welded Joints
Authors: Luo Yuxiao , Ma Renle , Tsutsumi Seiichiro
Published: January 2020

The evaluation of the stress concentration factor (SCF) at the notches of welds is of importance, especially for butt-welded joints that are widespread in the industry. Some empirical formulae can be found in the literature to estimate the SCF at the weld toes of butt-welded joints, while few solutions are available for the distorted joints under tensile fatigue test conditions. In the present study, the existing SCF formulae for butt-welded joints loaded in tension are examined and discussed. The influence of the weld width on SCF, which is commonly ignored or misestimated by existing solutions, is investigated comprehensively based on a large set of two-dimensional (2D) finite element analyses. Consequently, a new precise parametric formula for the elastic SCF at the weld toe of geometrically symmetric butt-welded joints under tension is proposed, together with a wide application range. Moreover, the analysis is also extended to consider joints with angular distortion. A two-step finite element analysis is employed to simulate the clamping and loading procedures in the fatigue test. Similarly, the parametric formulae for the assessment of clamping-induced stress and SCF caused by angular distortion are carried out as well based on the results from finite element analyses. The formulae proposed by this paper are finally tested and proved to be valid and precise.
Room-Temperature Synthesis of ZnS Nanoparticles Using Zinc Xanthates as Molecular Precursors
Authors: Mintcheva Neli , Gicheva Gospodinka , Panayotova Marinela , Kulinich Sergei A.
Published: January 2020

Molecular precursors are suitable starting compounds for preparation of semiconductor nanoparticles (NPs), which allow for control of atomic ratio, composition, monodispersity, and particle size of nanoscaled metal sulfides/oxides. In the present study, we carried out a one-pot synthesis of ZnS NPs in aqueous triethanolamine medium at room temperature, from molecular precursor zinc xanthate as a source of both Zn2+ and S2− ions. Furthermore, we compared the products obtained from zinc ethylxanthate (Zn(C2H5OCS2)2) and zinc amylxanthate (Zn(C5H11OCS2)2). The as-prepared ZnS NPs were found to crystallize in cubic phase, which usually forms at low temperatures, with the dimension dependent on the xanthate precursor used. The long carbon-chain xanthate Zn(C5H11OCS2)2 gave spherically shaped NPs with an average diameter of 19 nm, while the NPs that originated from zinc ethylxanthate had a mean size of ~26 nm. Both nanomaterials had surface sulfur vacancies that extended their absorption spectra toward the visible region and reduced the band gap. This allowed both materials to demonstrate photocatalytic performance under visible-light irradiation. Photodegradation of methylene blue over newly prepared ZnS NPs was tested under visible light, demonstrating efficiency of 50%–60% after 180 min.
Cytotoxicity, Antioxidant, Antibacterial, and Photocatalytic Activities of ZnO–CdS Powders
Authors: Zgura Irina , Preda Nicoleta , Enculescu Monica , Diamandescu Lucian , Negrila Catalin , Bacalum Mihaela , Ungureanu Camelia , Barbinta-Patrascu Marcela Elisabeta
Published: January 2020

In this work, ZnO–CdS composite powders synthesized by a simple chemical precipitation method were thoroughly characterized. The morphological, structural, compositional, photocatalytical, and biological properties of the prepared composites were investigated in comparison with those of the pristine components and correlated with the CdS concentration. ZnO–CdS composites contain flower-like structures, their size being tuned by the CdS amount added during the chemical synthesis. The photocatalytic activity of the composites was analyzed under UV irradiation using powders impregnated with methylene blue; the tests confirming that the presence of CdS along the ZnO in composites can improve the dye discoloration. The biological properties such as antioxidant capacity, antibacterial activity, and cytotoxicity of the ZnO, CdS, and ZnO–CdS composites were evaluated. Thus, the obtained composites presented medium antioxidant effect, biocidal activity against Escherichia coli, and no toxicity (at concentrations less than 0.05 mg/mL for composites with a low CdS amount) for human fibroblast cells. Based on these results, such composites can be used as photocatalytic and/or biocidal additives for photoactive coatings, paints, or epoxy floors, which in their turn can provide a cleaner and healthier environment.
Dynamic Tensile Behavior of Steel HRB500E Reinforcing Bar at Low, Medium, and High Strain Rates
Authors: Zeng Xiang , Huo Jingsi , Wang Haitao , Wang Zhan , Elchalakani Mohamed
Published: January 2020

The strain rate effect of engineering materials should be considered in the assessment of the performance of reinforced concrete (RC) structures under extreme dynamic loads such as blast and impact. However, the strain rate behavior of 500 MPa-grade anti-earthquake hot-rolled high-strength ribbed bar (HRB500E), used in critical RC members to improve the anti-earthquake performance, has not been investigated and reported in the open literature. That restricts its application in RC structures subjected to extreme dynamic loads. In this paper, dynamic tensile tests of HRB500E steel were conducted using an electromechanical universal testing machine and a servo-hydraulic high-speed testing machine. The stress–strain curves at strain rates ranging from 0.00025 to 550 s−1 were obtained where HRB500E steel was found significantly sensitive to strain rate. Existing formulations to evaluate the dynamic increase factor for yield stress (DIFy) are found to be not suitable for HRB500E steel, thus the widely used Cowper–Symonds and Malvar models for predicting the DIFy were modified based on the test results. Furthermore, the parameter of the Mander material model for describing engineering stress–strain relationship was also calibrated. Finally, the Johnson-Cook and proposed constitutive models for the true stress–strain relationship were examined. The proposed constitutive model can provide better prediction accuracy for yield stress than the Johnson-Cook model.
Performance of MIL-101(Cr)/Water Working Pair Adsorption Refrigeration System Based on a New Type of Adsorbent Filling Method
Authors: Liu Zhongbao , Zhao Banghua , Zhu Longqian , Lou Fengfei , Yan Jiawen
Published: January 2020

MIL-101(Cr) and water were applied to adsorption refrigeration technology. MIL-101(Cr) was prepared by hydrothermal synthesis method and characterized by X-ray diffraction patterns (XRD), Fourier transform infrared spectroscopy (FTIR), N2 adsorption–desorption measurement at 77 K, thermal gravimetric analysis (TGA) and scanning electron microscope (SEM). The adsorption isotherms of water vapor on MIL-101(Cr) were investigated by using a gravimetric water sorption analyzer. This study established the basic adsorption cycle mathematical model and used MATLAB/Simulink for the simulation. The control variable method was used to simulate the effect on the cooling capacity and coefficient of performance (COP) when the desorption temperature changed. When the adsorption temperature was 35 °C, the evaporation temperatures were 15 °C and 20 °C, and the amount of water vapor equilibrium adsorption on MIL-101 (Cr), Cooling power per unit adsorbent mass (SCP), and COP were measured by using the adsorption performance test rig on the basis of a new type of powder adsorbent filling method.
Nanotechnology Scaffolds for Alveolar Bone Regeneration
Authors: Funda Goker , Taschieri Silvio , Bruno Giannì Aldo , Grecchi Emma , Paolo Savadori , Girolamo Donati , Del Fabbro Massimo
Published: January 2020

In oral biology, tissue engineering aims at regenerating functional tissues through a series of key events that occur during alveolar/periodontal tissue formation and growth, by means of scaffolds that deliver signaling molecules and cells. Due to their excellent physicochemical properties and biomimetic features, nanomaterials are attractive alternatives offering many advantages for stimulating cell growth and promoting tissue regeneration through tissue engineering. The main aim of this article was to review the currently available literature to provide an overview of the different nano-scale scaffolds as key factors of tissue engineering for alveolar bone regeneration procedures. In this narrative review, PubMed, Medline, Scopus and Cochrane electronic databases were searched using key words like “tissue engineering”, “regenerative medicine”, “alveolar bone defects”, “alveolar bone regeneration”, “nanomaterials”, “scaffolds”, “nanospheres” and “nanofibrous scaffolds”. No limitation regarding language, publication date and study design was set. Hand-searching of the reference list of identified articles was also undertaken. The aim of this article was to give a brief introduction to review the role of different nanoscaffolds for bone regeneration and the main focus was set to underline their role for alveolar bone regeneration procedures.
Growth, Stratification, and Liberation of Phosphorus-Rich C2S in Modified BOF Steel Slag
Authors: Rao Lei , Dong Yuanchi , Gui Mancheng , Zhang Yaohui , Shen Xingmei , Wu Xingrong , Cao Fabin
Published: January 2020

Basic oxygen furnace (BOF) slag was modified by adding 3.5% SiO2 and holding at 1673 K for 0, 5, 40, 90, 240, or 360 min. Kilo-scale modification was also carried out. The growth, stratification, and liberation of P-rich C2S in the modified slag were investigated. The optimum holding time was 240 min, and 90% of C2S grains were above 30 μm in size. The phosphorus content increased with holding time, and after modification, the phosphorus content in C2S was nearly three times higher than that in the original slag (2.23%). Obvious stratification of C2S was observed in the kilo-scale modification. Upper C2S particles with a relatively larger size of 20–110 μm was independent of RO (FeO-MgO-MnO solid solution) and spinel, which is favorable for liberation. Lower C2S was less than 3 μm and was embedded in spinel, which is not conducive to liberation. The content of phosphorus in upper C2S (6.60%) was about twice that of the lower (3.80%). After grinding, most of the upper C2S existed as free particles and as locked particles in the lower. The liberation degree of C2S in the upper increased with grinding time, from 86.02% to 95.92% in the range of 30–300 s, and the optimum grinding time was 180 s. For the lower slag grinding for 300 s, the liberation degree of C2S was 40.07%.
The Regularity of Edge Rings and Matching Numbers
Authors: Herzog Jürgen , Hibi Takayuki
Published: January 2020

Let K [ G ] denote the edge ring of a finite connected simple graph G on [ d ] and mat ( G ) the matching number of G. It is shown that reg ( K [ G ] ) ≤ mat ( G ) if G is non-bipartite and K [ G ] is normal, and that reg ( K [ G ] ) ≤ mat ( G ) − 1 if G is bipartite.
A Lyapunov-Type Inequality for Partial Differential Equation Involving the Mixed Caputo Derivative
Authors: Wang Jie , Zhang Shuqin
Published: January 2020

In this work, we derive a Lyapunov-type inequality for a partial differential equation on a rectangular domain with the mixed Caputo derivative subject to Dirichlet-type boundary conditions. The obtained inequality provides a necessary condition for the existence of nontrivial solutions to the considered problem and an example is given to illustrate it. Moreover, we present some applications to demonstrate the effectiveness of the new results.
Bifurcations along the Boundary Curves of Red Fixed Components in the Parameter Space for Uniparametric, Jarratt-Type Simple-Root Finders
Authors: Lee Min-Young , Kim Young Ik
Published: January 2020

Bifurcations have been studied with an extensive analysis of boundary curves of red, fixed components in the parametric space for a uniparametric family of simple-root finders under the Möbius conjugacy map applied to a quadratic polynomial. An elementary approach from the perspective of a plane curve theory properly describes the geometric figures resembling a circle or cardioid to characterize the underlying boundary curves that are parametrically expressed. Moreover, exact bifurcation points for satellite components on the boundaries have been found, according to the fact that the tangent line at a bifurcation point simultaneously touches the red fixed component and the satellite component. Computational experiments implemented with examples well reflect the significance of the theoretical backgrounds pursued in this paper.
Nonlinear Spatiotemporal Viral Infection Model with CTL Immunity: Mathematical Analysis
Authors: Danane Jaouad , Allali Karam , Tine Léon Matar , Volpert Vitaly
Published: January 2020

A mathematical model describing viral dynamics in the presence of the latently infected cells and the cytotoxic T-lymphocytes cells (CTL), taking into consideration the spatial mobility of free viruses, is presented and studied. The model includes five nonlinear differential equations describing the interaction among the uninfected cells, the latently infected cells, the actively infected cells, the free viruses, and the cellular immune response. First, we establish the existence, positivity, and boundedness for the suggested diffusion model. Moreover, we prove the global stability of each steady state by constructing some suitable Lyapunov functionals. Finally, we validated our theoretical results by numerical simulations for each case.
On Canonical Almost Geodesic Mappings of Type π2(e)
Authors: Berezovski Volodymyr , Mikeš Josef , Rýparová Lenka , Sabykanov Almazbek
Published: January 2020

In the paper, we consider canonical almost geodesic mappings of type π 2 ( e ) . We have found the conditions that must be satisfied for the mappings to preserve the Riemann tensor. Furthermore, we consider canonical almost geodesic mappings of type π 2 ( e ) of spaces with affine connections onto symmetric spaces. The main equations for the mappings are obtained as a closed mixed system of Cauchy-type Partial Differential Equations. We have found the maximum number of essential parameters which the solution of the system depends on.
On a New Extended Hardy–Hilbert’s Inequality with Parameters
Authors: Yang Bicheng , Wu Shanhe , Liao Jianquan
Published: January 2020

In this paper, by introducing parameters and weight functions, with the help of the Euler–Maclaurin summation formula, we establish the extension of Hardy–Hilbert’s inequality and its equivalent forms. The equivalent statements of the best possible constant factor related to several parameters are provided. The operator expressions and some particular cases are also discussed.
On the Asymptotic Behavior of D-Solutions to the Displacement Problem of Linear Elastostatics in Exterior Domains
Authors: Coscia Vincenzo
Published: January 2020

We study the asymptotic behavior of solutions with finite energy to the displacement problem of linear elastostatics in a three-dimensional exterior Lipschitz domain.
A Novel Delay-Dependent Asymptotic Stability Conditions for Differential and Riemann-Liouville Fractional Differential Neutral Systems with Constant Delays and Nonlinear Perturbation
Authors: Chartbupapan Watcharin , Bagdasar Ovidiu , Mukdasai Kanit
Published: January 2020

The novel delay-dependent asymptotic stability of a differential and Riemann-Liouville fractional differential neutral system with constant delays and nonlinear perturbation is studied. We describe the new asymptotic stability criterion in the form of linear matrix inequalities (LMIs), using the application of zero equations, model transformation and other inequalities. Then we show the new delay-dependent asymptotic stability criterion of a differential and Riemann-Liouville fractional differential neutral system with constant delays. Furthermore, we not only present the improved delay-dependent asymptotic stability criterion of a differential and Riemann-Liouville fractional differential neutral system with single constant delay but also the new delay-dependent asymptotic stability criterion of a differential and Riemann-Liouville fractional differential neutral equation with constant delays. Numerical examples are exploited to represent the improvement and capability of results over another research as compared with the least upper bounds of delay and nonlinear perturbation.
A Partitioning Method for Friction Stir Welded Joint of AA2219 Based on Tensile Test
Authors: Cao Guanglong , Ren Mingfa , Zhang Yahui , Peng Weibin , Li Tong
Published: January 2020

The partition of aluminum alloy welded joint often depends on microscopic methods such as scanning electron microscopy before. This paper provides a novel partitioning method, which can obtain the material properties and partition results at the same time based on tensile test. The mechanical properties of every point on the whole welded joint are first obtained by the digital image correlation (DIC) method. Then, the mechanical property function of the weld joint along the weld center is established due to the changes of plastic property and strain hardening exponent at each point and the boundary between different areas is then determined. Metallographic detection technology and nano-mechanical testing techniques are employed to validate this partitioning scheme. The partition result of the strategy proposed in this paper is consistent with the partitioning result of the classical method. Compared to classical method, the proposed partitioning method is more practical and effective, as it can obtain mechanical properties and partition boundary through a single tensile test and reduce the cost of metallographic test.
Assessment of Silica Recovery from Metallurgical Mining Waste, by Means of Column Flotation
Authors: Salinas-Rodriguez Eleazar , Flores-Badillo Javier , Hernandez-Avila Juan , Cerecedo-Saenz Eduardo , Gutierrez-Amador Ma. del Pilar , Jeldres Ricardo I. , Toro Normam
Published: January 2020

The generation of mining waste commonly led to the use of spaces for its disposal. Challenges like mitigating the damage to surrounding communities have promoted the need to reuse, recycle and/or reduce their generation. Besides, these residues may become a source of materials, which are capable of being recovered and reused in several industries, minimizing the environmental impact. In the mining region of Pachuca, Mexico, waste from the mining industry have been generated for more than 100 years, which have a high SiO2 content that can be recovered for various industrial applications. This work aims to recover silica from a material of the Dos Carlos dam. A columnar system composed of two-stage of cleaning was used, considering a JLT (surface liquid rate) value of 0.45 and 0.68 cm/s, respectively; while the Jg (surface gas rate) value was 0.30 cm/s for both stages. Similar bubble sizes in the range of Jg 0.10 to 0.30 cm/s, with values between 0.14 and 0.16 cm in the first stage, and 0.05 to 0.06 cm in the second one. This provided a recovery of 75.10% for all the allotropic phases of silica (quartz, trydimite, and cristobalite) leaving a concentration of 24.90% of a feldspathic phase (orthoclase), as flotation tails.
Comparison of Finite Element Methods in Fusion Welding Processes—A Review
Authors: Marques Eva S. V. , Silva Francisco J. G. , Pereira António B.
Published: January 2020

Currently, welding processes have become one of the most used methods for joining materials in all kinds of industries, thanks to properties such as high speed and high tensile strength. However, despite these advantages, this type of connection method has some drawbacks, for example, residual stress and structural distortion, mainly due to the process thermal cycles. Structural distortion is one of the major concerns of industrial joining practice. In order to decrease distortion, the variation of welding sequence, direction, and clamping conditions, have been applied through several years, by trial and error tests. However, numerical simulation enables virtual examination of the welding, mainly due to the progress on the numerical methods, which stimulated the research on welding simulation models. These models can cover a wide spectrum of physical and thermal processes occurring during, and after welding. The aim of this paper is to provide wider information about types of finite element method (FEM) in fusion welding processes and to demonstrate the accuracy of FEM models results compared to experimental.
Investigation on Fracture of a 6014-T4 Aluminum Alloy Sheet in the Flanging and Hemming Process Based on Numerical and Experimental Methods
Authors: Gu Zhengwei , Wang Gang , Yu Ge
Published: January 2020

The fracture of a flat-surface straight-edge hemmed component of aluminum alloy sheets was investigated in this study. The specimen was made of 1 mm thick 6014-T4. Natural aging characteristics of 6014-T4 were studied via uniaxial tensile tests. The results show that the yield stress and ultimate tensile strength increased while the uniform elongation, strain hardening exponent, and plastic strain ratio decreased during the natural aging period, which worsened the formability. The sheet was biaxially stretched to obtain a pre-strain before the flanging and hemming operation. The influence of the flanging radius on the fracture was evaluated using experimental and numerical methods, and the optimum values were obtained. The comparison between the roller hemming and die hemming process proved that the former tends to produce better formability.
Effect of Friction Stir Processing on Microstructural, Mechanical, and Corrosion Properties of Al-Si12 Additive Manufactured Components
Authors: Moeini Ghazal , Sajadifar Seyed Vahid , Engler Tom , Heider Ben , Niendorf Thomas , Oechsner Matthias , Böhm Stefan
Published: January 2020

Additive manufacturing (AM) is an advanced manufacturing process that provides the opportunity to build geometrically complex and highly individualized lightweight structures. Despite its many advantages, additively manufactured components suffer from poor surface quality. To locally improve the surface quality and homogenize the microstructure, friction stir processing (FSP) technique was applied on Al-Si12 components produced by selective laser melting (SLM) using two different working media. The effect of FSP on the microstructural evolution, mechanical properties, and corrosion resistance of SLM samples was investigated. Microstructural investigation showed a considerable grain refinement in the friction stirred area, which is due to the severe plastic deformation and dynamic recrystallization of the material in the stir zone. Micro-hardness measurements revealed that the micro-hardness values of samples treated using FSP are much lower compared to SLM components in the as-built condition. This reduction of hardness values in samples treated with FSP can be explained by the dissolution of the very fine Si-phase network, being characteristic for SLM samples, during FSP. Surface topography also demonstrated that the FSP results in the reduction of surface roughness and increases the homogeneity of the SLM microstructure. Decreased surface roughness and grain size refinement in combination with the dissolved Si-phase network of the FSP treated material result in considerable changes in corrosion behavior. This work addresses the corrosion properties of surface treated additive manufactured Al-Si12 by establishing adequate microstructure-property relationships. The corrosion behavior of SLM-manufactured Al-Si12 alloys is shown to be improved by FSP-modification of the surfaces.
Reliability Analysis of an Epileptic Seizure Detector Powered by an Energy Harvester
Authors: Kim Sunhee , Ju Suna , Ji Chang-Hyeon
Published: January 2020

Due to a limited lifetime of a battery, energy harvesters have been studied as alternative energy sources for implantable biomedical devices such as an implantable stimulator for epileptic seizure suppression. However, energy harvesters have weakness in providing stable power. We designed a neural recording circuit powered solely by a piezoelectric energy harvester, and applied its output to a seizure detector to analyze the reliability of the recorded signal. Performance of the seizure detector was evaluated. We found that the average time differences between with and without voltage variances were about 0.05 s under regular vibrations and about 0.07 s under irregular vibrations, respectively. The ratio of average true positive alarm period varied within about 0.02% under regular vibrations and 0.029% under irregular vibrations, respectively. The ratio of average false positive alarm period varied within about 0.004% under regular vibrations and 0.014% under irregular vibrations, respectively. This paper presents a reliability analysis of an epileptic seizure detector with a neural signal recording circuit powered by a piezoelectric energy harvester. The results showed that a supply voltage variance within ±10% could be acceptable for reliable operation of a seizure detector.
Deciphering the Symbiotic Significance of Quorum Sensing Systems of Sinorhizobium fredii HH103
Authors: Acosta-Jurado Sebastián , Alías-Villegas Cynthia , Almozara Andrés , Espuny M. Rosario , Vinardell José-María , Pérez-Montaño Francisco
Published: January 2020

Quorum sensing (QS) is a bacterial cell-to-cell signaling mechanism that collectively regulates and synchronizes behaviors by means of small diffusible chemical molecules. In rhizobia, QS systems usually relies on the synthesis and detection of N-acyl-homoserine lactones (AHLs). In the model bacterium Sinorhizobium meliloti functions regulated by the QS systems TraI-TraR and SinI-SinR(-ExpR) include plasmid transfer, production of surface polysaccharides, motility, growth rate and nodulation. These systems are also present in other bacteria of the Sinorhizobium genus, with variations at the species and strain level. In Sinorhizobium fredii NGR234 phenotypes regulated by QS are plasmid transfer, growth rate, sedimentation, motility, biofilm formation, EPS production and copy number of the symbiotic plasmid (pSym). The analysis of the S. fredii HH103 genomes reveal also the presence of both QS systems. In this manuscript we characterized the QS systems of S. fredii HH103, determining that both TraI and SinI AHL-synthases proteins are responsible of the production of short- and long-chain AHLs, respectively, at very low and not physiological concentrations. Interestingly, the main HH103 luxR-type genes, expR and traR, are split into two ORFs, suggesting that in S. fredii HH103 the corresponding carboxy-terminal proteins, which contain the DNA-binding motives, may control target genes in an AHL-independent manner. The presence of a split traR gene is common in other S. fredii strains.