bluuebunny/crossref_metadata_2025 huggingface dataset:
Time-Course Transcriptome Study Reveals Mode of bZIP Transcription Factors on Light Exposure in Arabidopsis
Authors: Kurihara Yukio , Makita Yuko , Shimohira Haruka , Matsui Minami
Published: March 2020

The etiolation process, which occurs after germination, is terminated once light is perceived and then de-etiolation commences. During the de-etiolation period, monochromatic lights (blue, red and far-red) induce differences in gene expression profiles and plant behavior through their respective photoreceptors. ELONGATED HYPOCOTYL 5 (HY5), a bZIP-type transcription factor (TF), regulates gene expression in the de-etiolation process, and other bZIP TFs are also involved in this regulation. However, transcriptomic changes that occur in etiolated seedlings upon monochromatic light irradiation and the relationship with the bZIP TFs still remain to be elucidated. Here, we track changes in the transcriptome after exposure to white, blue, red and far-red light following darkness and reveal both shared and non-shared trends of transcriptomic change between the four kinds of light. Interestingly, after exposure to light, HY5 expression synchronized with those of the related bZIP TF genes, GBF2 and GBF3, rather than HY5 HOMOLOG (HYH). To speculate on the redundancy of target genes between the bZIP TFs, we inspected the genome-wide physical binding sites of homodimers of seven bZIP TFs, HY5, HYH, GBF1, GBF2, GBF3, GBF4 and EEL, using an in vitro binding assay. The results reveal large overlaps of target gene candidates, indicating a complicated regulatory literature among TFs. This work provides novel insight into understanding the regulation of gene expression of the plant response to monochromatic light irradiation.
Proteomics Analysis Reveals that Warburg Effect along with Modification in Lipid Metabolism Improves In Vitro Embryo Development under Low Oxygen
Authors: Shahzad Qaisar , Pu Liping , Ahmed Wadood Armughan , Waqas Muhammad , Xie Long , Shekhar Pareek Chandra , Xu Huiyan , Liang Xianwei , Lu Yangqing
Published: March 2020

The molecular mechanism regulating embryo development under reduced oxygen tension remains elusive. This study aimed to identify the molecular mechanism impacting embryo development under low oxygen conditions. Buffalo embryos were cultured under 5% or 20% oxygen and were evaluated according to their morphological parameters related to embryo development. The protein profiles of these embryos were compared using iTRAQ-based quantitative proteomics. Physiological O2 (5%) significantly promoted blastocyst yield, hatching rate, embryo quality and cell count as compared to atmospheric O2 (20%). The embryos in the 5% O2 group had an improved hatching rate of cryopreserved blastocysts post-warming (p < 0.05). Comparative proteome profiles of hatched blastocysts cultured under 5% vs. 20% O2 levels identified 43 differentially expressed proteins (DEPs). Functional analysis indicated that DEPs were mainly associated with glycolysis, fatty acid degradation, inositol phosphate metabolism and terpenoid backbone synthesis. Our results suggest that embryos under physiological oxygen had greater developmental potential due to the pronounced Warburg Effect (aerobic glycolysis). Moreover, our proteomic data suggested that higher lipid degradation, an elevated cholesterol level and a higher unsaturated to saturated fatty acid ratio might be involved in the better cryo-survival ability reported in embryos cultured under low oxygen. These data provide new information on the early embryo protein repertoire and general molecular mechanisms of embryo development under varying oxygen levels.
Identification of Candidate Genes Involved in Curd Riceyness in Cauliflower
Authors: Zhao Zhenqing , Sheng Xiaoguang , Yu Huifang , Wang Jiansheng , Shen Yusen , Gu Honghui
Published: March 2020

“Riceyness” refers to the precocious development of flower bud initials over the curd surface of cauliflower, and it is regarded as undesirable for the market. The present study aimed to identify the candidate loci and genes responsible for the morphological difference in riceyness between a pair of cauliflower sister lines. Genetic analysis revealed that riceyness is controlled by a single dominant locus. An F2 population derived from the cross between these sister lines was used to construct “riceyness” and “non-riceyness” bulks, and then it was subjected to BSA-seq. On the basis of the results of Δ(SNP-index) analysis, a 4.0 Mb candidate region including 22 putative SNPs was mapped on chromosome C04. Combining the RNA-seq, gene function annotation, and target sequence analysis among two parents and other breeding lines, an orthologous gene of the Arabidopsis gene SOC1, Bo4g024850 was presumed as the candidate gene, and an upstream SNP likely resulted in riceyness phenotype via influencing the expression levels of Bo4g024850. These results are helpful to understand the genetic mechanism regulating riceyness, and to facilitate the molecular improvement on cauliflower curds.
Anti-Inflammatory and Anti-Oxidative Effects of luteolin-7-O-glucuronide in LPS-Stimulated Murine Macrophages through TAK1 Inhibition and Nrf2 Activation
Authors: Cho Young-Chang , Park Jiyoung , Cho Sayeon
Published: March 2020

Various herbal extracts containing luteolin-7-O-glucuronide (L7Gn) have been traditionally used to treat inflammatory diseases. However, systemic studies aimed at elucidating the anti-inflammatory and anti-oxidative mechanisms of L7Gn in macrophages are insufficient. Herein, the anti-inflammatory and anti-oxidative effects of L7Gn and their underlying mechanisms of action in macrophages were explored. L7Gn inhibited nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages by transcriptional regulation of inducible NO synthase (iNOS) in a dose-dependent manner. The mRNA expression of inflammatory mediators, including cyclooxygenase-2 (COX-2), interleukin-6 (IL-6), IL-1β, and tumor necrosis factor-α (TNF-α), was inhibited by L7Gn treatment. This suppression was mediated through transforming growth factor beta-activated kinase 1 (TAK1) inhibition that leads to reduced activation of nuclear factor-κB (NF-κB), p38, and c-Jun N-terminal kinase (JNK). L7Gn also enhanced the radical scavenging effect and increased the expression of anti-oxidative regulators, including heme oxygenase-1 (HO-1), glutamate-cysteine ligase catalytic subunit (GCLC), and NAD(P)H quinone oxidoreductase 1 (NQO1), by nuclear factor-erythroid 2 p45-related factor 2 (Nrf2) activation. These results indicate that L7Gn exhibits anti-inflammatory and anti-oxidative properties in LPS-stimulated murine macrophages, suggesting that L7Gn may be a suitable candidate to treat severe inflammation and oxidative stress.
Role of microRNAs in the Development of Cardiovascular Disease in Systemic Autoimmune Disorders
Authors: Lopez-Pedrera Chary , Barbarroja Nuria , Patiño-Trives Alejandra Mª , Luque-Tévar Maria , Torres-Granados Carmen , Aguirre-Zamorano Mª Angeles , Collantes-Estevez Eduardo , Pérez-Sánchez Carlos
Published: March 2020

Rheumatoid Arthritis (RA), Systemic lupus erythematosus (SLE) and antiphospholipid syndrome (APS) are the systemic autoimmune diseases (SADs) most associated with an increased risk of developing cardiovascular (CV) events. Cardiovascular disease (CVD) in SADs results from a complex interaction between traditional CV-risk factors, immune deregulation and disease activity. Oxidative stress, dyslipidemia, endothelial dysfunction, inflammatory/prothrombotic mediators (cytokines/chemokines, adipokines, proteases, adhesion-receptors, NETosis-derived-products, and intracellular-signaling molecules) have been implicated in these vascular pathologies. Genetic and genomic analyses further allowed the identification of signatures explaining the pro-atherothrombotic profiles in RA, SLE and APS. However, gene modulation has left significant gaps in our understanding of CV co-morbidities in SADs. MicroRNAs (miRNAs) are emerging as key post-transcriptional regulators of a suite of signaling pathways and pathophysiological effects. Abnormalities in high number of miRNA and their associated functions have been described in several SADs, suggesting their involvement in the development of atherosclerosis and thrombosis in the setting of RA, SLE and APS. This review focusses on recent insights into the potential role of miRNAs both, as clinical biomarkers of atherosclerosis and thrombosis in SADs, and as therapeutic targets in the regulation of the most influential processes that govern those disorders, highlighting the potential diagnostic and therapeutic properties of miRNAs in the management of CVD.
A Silent Exonic Mutation in a Rice Integrin-α FG-GAP Repeat-Containing Gene Causes Male-Sterility by Affecting mRNA Splicing
Authors: Zou Ting , Zhou Dan , Li Wenjie , Yuan Guoqiang , Tao Yang , He Zhiyuan , Zhang Xu , Deng Qiming , Wang Shiquan , Zheng Aiping , Zhu Jun , Liang Yueyang , Liu Huainian , Wang Aijun , Wang Lingxia , Li Ping , Li Shuangcheng
Published: March 2020

Pollen development plays crucial roles in the life cycle of higher plants. Here we characterized a rice mutant with complete male-sterile phenotype, pollen-less 1 (pl1). pl1 exhibited smaller anthers with arrested pollen development, absent Ubisch bodies, necrosis-like tapetal hypertrophy, and smooth anther cuticular surface. Molecular mapping revealed a synonymous mutation in the fourth exon of PL1 co-segregated with the mutant phenotype. This mutation disrupts the exon-intron splice junction in PL1, generating aberrant mRNA species and truncated proteins. PL1 is highly expressed in the tapetal cells of developing anther, and its protein is co-localized with plasma membrane (PM) and endoplasmic reticulum (ER) signal. PL1 encodes an integrin-α FG-GAP repeat-containing protein, which has seven β-sheets and putative Ca2+-binding motifs and is broadly conserved in terrestrial plants. Our findings therefore provide insights into both the role of integrin-α FG-GAP repeat-containing protein in rice male fertility and the influence of exonic mutation on intronic splice donor site selection.
Upregulation of Neuronal Rheb(S16H) for Hippocampal Protection in the Adult Brain
Authors: Moon Gyeong Joon , Shin Minsang , Kim Sang Ryong
Published: March 2020

Ras homolog protein enriched in brain (Rheb) is a key activator of mammalian target of rapamycin complex 1 (mTORC1). The activation of mTORC1 by Rheb is associated with various processes such as protein synthesis, neuronal growth, differentiation, axonal regeneration, energy homeostasis, autophagy, and amino acid uptake. In addition, Rheb–mTORC1 signaling plays a crucial role in preventing the neurodegeneration of hippocampal neurons in the adult brain. Increasing evidence suggests that the constitutive activation of Rheb has beneficial effects against neurodegenerative diseases such as Alzheimer’s disease (AD) and Parkinson’s disease (PD). Our recent studies revealed that adeno-associated virus serotype 1 (AAV1) transduction with Rheb(S16H), a constitutively active form of Rheb, exhibits neuroprotective properties through the induction of various neurotrophic factors, promoting neurotrophic interactions between neurons and astrocytes in the hippocampus of the adult brain. This review provides compelling evidence for the therapeutic potential of AAV1–Rheb(S16H) transduction in the hippocampus of the adult brain by exploring its neuroprotective effects and mechanisms.
The Role of Biofilms Developed under Different Anthropogenic Pressure on Recruitment of Macro-Invertebrates
Authors: Cacabelos Eva , Ramalhosa Patrício , Canning-Clode João , Troncoso Jesús S. , Olabarria Celia , Delgado Cristina , Dobretsov Sergey , Gestoso Ignacio
Published: March 2020

Microbial biofilms can be key mediators for settlement of macrofoulers. The present study examines the coupled effects of microbial biofilms and local environmental conditions on the composition, structure and functioning of macrofouling assemblages. Settlement of invertebrates over a gradient of human-impacted sites was investigated on local biofilms and on biofilms developed in marine protected areas (MPAs). Special attention was given to the presence of non-indigenous species (NIS), a global problem that can cause important impacts on local assemblages. In general, the formation of macrofouling assemblages was influenced by the identity of the biofilm. However, these relationships varied across levels of anthropogenic pressure, possibly influenced by environmental conditions and the propagule pressure locally available. While the NIS Watersipora subatra seemed to be inhibited by the biofilm developed in the MPA, Diplosoma cf. listerianum seemed to be attracted by biofilm developed in the MPA only under mid anthropogenic pressure. The obtained information is critical for marine environmental management, urgently needed for the establishment of prevention and control mechanisms to minimize the settlement of NIS and mitigate their threats.
Interaction between Calcium Chelators and the Activity of P2X7 Receptors in Mouse Motor Synapses
Authors: Miteva Anna , Gaydukov Alexander , Balezina Olga
Published: March 2020

The ability of P2X7 receptors to potentiate rhythmically evoked acetylcholine (ACh) release through Ca2+ entry via P2X7 receptors and via L-type voltage-dependent Ca2+ channels (VDCCs) was compared by loading Ca2+ chelators into motor nerve terminals. Neuromuscular preparations of the diaphragms of wild-type (WT) mice and pannexin-1 knockout (Panx1−/−) mice, in which ACh release is potentiated by the disinhibition of the L-type VDCCs upon the activation of P2X7 receptors, were used. Miniature end-plate potentials (MEPPs) and evoked end-plate potentials (EPPs) were recorded when the motor terminals were loaded with slow or fast Ca2+ chelators (EGTA-AM or BAPTA-AM, respectively, 50 μM). In WT and Panx1−/− mice, EGTA-AM did not change either spontaneous or evoked ACh release, while BAPTA-AM inhibited synaptic transmission by suppressing the quantal content of EPPs throughout the course of the short rhythmic train (50 Hz, 1 s). In the motor synapses of either WT or Panx1−/− mice in the presence of BAPTA-AM, the activation of P2X7 receptors by BzATP (30 μM) returned the EPP quantal content to the control level. In the neuromuscular junctions (NMJs) of Panx1−/− mice, EGTA-AM completely prevented the BzATP-induced increase in EPP quantal content. After Panx1−/− NMJs were treated with BAPTA-AM, BzATP lost its ability to enhance the EPP quantal content to above the control level. Nitrendipine (1 μM), an inhibitor of L-type VDCCs, was unable to prevent this BzATP-induced enhancement of EPP quantal content to the control level. We propose that the activation of P2X7 receptors may provide additional Ca2+ entry into motor nerve terminals, which, independent of the modulation of L-type VDCC activity, can partially reduce the buffering capacity of Ca2+ chelators, thereby providing sufficient Ca2+ signals for ACh secretion at the control level. However, the activity of both Ca2+ chelators was sufficient to eliminate Ca2+ entry via L-type VDCCs activated by P2X7 receptors and increase the EPP quantal content in the NMJs of Panx1−/− mice to above the control level.
Effect of Streptozotocin-Inducted Diabetes on the Pathophysiology of Enteric Neurons in the Small Intestine Based on the Porcine Diabetes Model
Authors: Bulc Michał , Całka Jarosław , Palus Katarzyna
Published: March 2020

Hyperglycemia is one of the main causes of diabetes complications. Gastrointestinal (GI) disturbances are one of the most frequent complications during diabetes. The porcine digestive tract possesses physiological and pathological similarities to the human digestive tract. This also applies to the innervation of the gastrointestinal tract. In this study, the influence of experimentally-inducted hyperglycemia was examined on the expression of vesicular acetylcholine transporter (VAChT), cocaine- and amphetamine-regulated transcript (CART), galanin (GAL), vasoactive intestinal polypeptide (VIP), and calcitonin gene-related peptide (CGRP) in the enteric nervous system (ENS) neurons in the small intestine of the pig. During the current study, an increased number of neurons containing CART, VIP, GAL, and CGRP under streptozotocin injection were observed. The augmentation of expression included all enteric plexuses present in the small intestine. The same results were obtained in the case of VAChT; namely, chronic hyperglycemia led to an increase in the number of neurons utilizing VAChT in all investigated plexuses. The obtained results suggested that the function of neuropeptides studied in this experiment depended on their localization in the ENS structures, as well as part of the GI tract. Diabetes led to alterations in the neurochemical phenotype of small intestine enteric neurons.
Transcriptomic and Network Analysis Identifies Shared and Unique Pathways across Dementia Spectrum Disorders
Authors: Santiago Jose A. , Bottero Virginie , Potashkin Judith A.
Published: March 2020

Background: Dementia is a growing public health concern with an estimated prevalence of 50 million people worldwide. Alzheimer’s disease (AD) and vascular and frontotemporal dementias (VaD, FTD), share many clinical, genetical, and pathological features making the diagnosis difficult. Methods: In this study, we compared the transcriptome from the frontal cortex of patients with AD, VaD, and FTD to identify dysregulated pathways. Results: Upregulated genes in AD were enriched in adherens and tight junctions, mitogen-activated protein kinase, and phosphatidylinositol 3-kinase and protein kinase B/Akt signaling pathways, whereas downregulated genes associated with calcium signaling. Upregulated genes in VaD were centered on infectious diseases and nuclear factor kappa beta signaling, whereas downregulated genes are involved in biosynthesis of amino acids and the pentose phosphate pathway. Upregulated genes in FTD were associated with ECM receptor interactions and the lysosome, whereas downregulated genes were involved in glutamatergic synapse and MAPK signaling. The transcription factor KFL4 was shared among the 3 types of dementia. Conclusions: Collectively, we identified similarities and differences in dysregulated pathways and transcription factors among the dementias. The shared pathways and transcription factors may indicate a potential common etiology, whereas the differences may be useful for distinguishing dementias.
On-treatment Serum Mac-2 Binding Protein Glycosylation Isomer (M2BPGi) Level and Risk of Hepatocellular Carcinoma Development in Patients with Chronic Hepatitis B during Nucleot(s)ide Analogue Therapy
Authors: Murata Ayato , Amano Nozomi , Sato Sho , Tsuzura Hironori , Tomishima Ko , Sato Shunsuke , Matsumoto Kohei , Shimada Yuji , Iijima Katsuyori , Genda Takuya
Published: March 2020

We aimed to analyze the serum level of a novel fibrosis marker, Mac-2-binding protein glycosylation isomer (M2BPGi), and its predictive value for hepatocellular carcinoma (HCC) development in chronic hepatitis B (CHB) under nucleot(s)ide analogue (NA) therapy. Serum M2BPGi levels were quantified in 147 CHB patients at baseline, 48 weeks after starting NA therapy, and at the patients’ last visit. The serum M2BPGi level serially decreased at each time point. During the median follow-up time of 6.6 years, 14 of 147 patients developed HCC. Multivariate Cox proportional hazard analysis demonstrated that high serum M2BPGi at 48 weeks was an independent risk factor for HCC development. A cutoff value of M2BPGi at 48 weeks > 1.5 showed an adjusted hazard ratio = 34.9 (95% confidence interval, 4.3–284.9). The 3- and 5-year cumulative incidence of HCC in patients with low M2BPGi were 0.9% and 4.2%, respectively, whereas those in patients with high M2BPGi were 10.1% and 25.6%, respectively (p < 0.001). In conclusion, Serum M2BPGi level at 48 weeks is a useful predictor for HCC development in patients with CHB who receive NA therapy.
Soluble Epoxide Hydrolase 2 Expression Is Elevated in Obese Humans and Decreased by Physical Activity
Authors: Khadir Abdelkrim , Kavalakatt Sina , Madhu Dhanya , Cherian Preethi , Al-Mulla Fahd , Abubaker Jehad , Tiss Ali
Published: March 2020

Epoxide hydrolase 2 (EPHX2) is an emerging therapeutic target in several immunometabolic disorders. EPHX2 metabolizes anti-inflammatory epoxyeicosatrienoic acids into pro-inflammatory diols. The contribution of EPHX2 activity to human obesity remains unexplored. We compared the expression of EPHX2 between lean and obese humans (n = 20 each) in subcutaneous adipose tissue (SAT) and peripheral blood mononuclear cells (PBMCs) using RT-PCR, Western Blot analysis, immunohistochemistry, and confocal microscopy before and after a 3-month physical activity regimen. We also assessed EPHX2 levels during preadipocyte differentiation in humans and mice. EPHX2 mRNA and protein expression were significantly elevated in obese subjects, with concomitant elevated endoplasmic reticulum (ER) stress components (the 78-kDa glucose-regulated protein; GRP78, and the Activating transcription factor 6; ATF6) and inflammatory markers (Tumor necrosis factor-α; TNFα, and Interleukin 6; IL6) as compared to controls (p < 0.05). EPHX2 mRNA levels strongly correlated with adiposity markers. In obese individuals, physical activity attenuated EPHX2 expression levels in both the SAT and PBMCs, with a parallel decrease in ER stress and inflammation markers. EPHX2 expression was also elevated during differentiation of both human primary and 3T3-L1 mouse preadipocytes. Mediators of cellular stress (palmitate, homocysteine, and macrophage culture medium) also increased EPHX2 expression in 3T3-L1 preadipocytes. Our findings suggest that EPHX2 upregulation is linked to ER stress in adiposity and that physical activity may attenuate metabolic stress by reducing EPHX2 expression.
Thiopurine Derivative-Induced Fpg/Nei DNA Glycosylase Inhibition: Structural, Dynamic and Functional Insights
Authors: Rieux Charlotte , Goffinont Stéphane , Coste Franck , Tber Zahira , Cros Julien , Roy Vincent , Guérin Martine , Gaudon Virginie , Bourg Stéphane , Biela Artur , Aucagne Vincent , Agrofoglio Luigi , Garnier Norbert , Castaing Bertrand
Published: March 2020

DNA glycosylases are emerging as relevant pharmacological targets in inflammation, cancer and neurodegenerative diseases. Consequently, the search for inhibitors of these enzymes has become a very active research field. As a continuation of previous work that showed that 2-thioxanthine (2TX) is an irreversible inhibitor of zinc finger (ZnF)-containing Fpg/Nei DNA glycosylases, we designed and synthesized a mini-library of 2TX-derivatives (TXn) and evaluated their ability to inhibit Fpg/Nei enzymes. Among forty compounds, four TXn were better inhibitors than 2TX for Fpg. Unexpectedly, but very interestingly, two dithiolated derivatives more selectively and efficiently inhibit the zincless finger (ZnLF)-containing enzymes (human and mimivirus Neil1 DNA glycosylases hNeil1 and MvNei1, respectively). By combining chemistry, biochemistry, mass spectrometry, blind and flexible docking and X-ray structure analysis, we localized new TXn binding sites on Fpg/Nei enzymes. This endeavor allowed us to decipher at the atomic level the mode of action for the best TXn inhibitors on the ZnF-containing enzymes. We discovered an original inhibition mechanism for the ZnLF-containing Fpg/Nei DNA glycosylases by disulfide cyclic trimeric forms of dithiopurines. This work paves the way for the design and synthesis of a new structural class of inhibitors for selective pharmacological targeting of hNeil1 in cancer and neurodegenerative diseases.
The Beta Subunit of Nascent Polypeptide Associated Complex Plays A Role in Flowers and Siliques Development of Arabidopsis thaliana
Authors: Fíla Jan , Klodová Božena , Potěšil David , Juříček Miloslav , Šesták Petr , Zdráhal Zbyněk , Honys David
Published: March 2020

The nascent polypeptide-associated (NAC) complex was described in yeast as a heterodimer composed of two subunits, α and β, and was shown to bind to the nascent polypeptides newly emerging from the ribosomes. NAC function was widely described in yeast and several information are also available about its role in plants. The knock down of individual NAC subunit(s) led usually to a higher sensitivity to stress. In Arabidopsis thaliana genome, there are five genes encoding NACα subunit, and two genes encoding NACβ. Double homozygous mutant in both genes coding for NACβ was acquired, which showed a delayed development compared to the wild type, had abnormal number of flower organs, shorter siliques and greatly reduced seed set. Both NACβ genes were characterized in more detail—the phenotype of the double homozygous mutant was complemented by a functional NACβ copy. Then, both NACβ genes were localized to nuclei and cytoplasm and their promoters were active in many organs (leaves, cauline leaves, flowers, pollen grains, and siliques together with seeds). Since flowers were the most affected organs by nacβ mutation, the flower buds’ transcriptome was identified by RNA sequencing, and their proteome by gel-free approach. The differential expression analyses of transcriptomic and proteomic datasets suggest the involvement of NACβ subunits in stress responses, male gametophyte development, and photosynthesis.
Migration, Remittances, and Forest Cover Change in Rural Guatemala and Chiapas, Mexico
Authors: Angelsen Arild , Aguilar-Støen Mariel , Ainembabazi John , Castellanos Edwin , Taylor Matthew
Published: March 2020

This article investigates how migration and remittances affect forest cover in eight rural communities in Guatemala and Chiapas, Mexico. Based on household surveys and remote sensing data, we found little evidence to support the widespread claim that migration takes pressure off forests. In the Chiapas sites, we observed no significant changes in forest cover since 1990, while in the Guatemalan sites, migration may have increased demand for agricultural land, leading to an average annual forest loss of 0.73% during the first decade of the millennium. We suggest that when attractive opportunities exist to invest in agriculture and land expansion, remittances and returnee savings provide fresh capital that is likely to increase pressure on forests. Our study also has implications for the understanding of migration flows; in particular, migration has not implied an exodus out of agriculture for the remaining household members nor for the returning migrants. On the contrary, returning migrants are more likely to be involved in farming activities after their return than they were before leaving.
Biodegradable Magnesium Bone Implants Coated with a Novel Bioceramic Nanocomposite
Authors: Razavi Mehdi , Fathi Mohammadhossein , Savabi Omid , Tayebi Lobat , Vashaee Daryoosh
Published: March 2020

Magnesium (Mg) alloys are being investigated as a biodegradable metallic biomaterial because of their mechanical property profile, which is similar to the human bone. However, implants based on Mg alloys are corroded quickly in the body before the bone fracture is fully healed. Therefore, we aimed to reduce the corrosion rate of Mg using a double protective layer. We used a magnesium-aluminum-zinc alloy (AZ91) and treated its surface with micro-arc oxidation (MAO) technique to first form an intermediate layer. Next, a bioceramic nanocomposite composed of diopside, bredigite, and fluoridated hydroxyapatite (FHA) was coated on the surface of MAO treated AZ91 using the electrophoretic deposition (EPD) technique. Our in vivo results showed a significant enhancement in the bioactivity of the nanocomposite coated AZ91 implant compared to the uncoated control implant. Implantation of the uncoated AZ91 caused a significant release of hydrogen bubbles around the implant, which was reduced when the nanocomposite coated implants were used. Using histology, this reduction in the corrosion rate of the coated implants resulted in an improved new bone formation and reduced inflammation in the interface of the implants and the surrounding tissue. Hence, our strategy using a MAO/EPD of a bioceramic nanocomposite coating (i.e., diopside-bredigite-FHA) can significantly reduce the corrosion rate and improve the bioactivity of the biodegradable AZ91 Mg implant.
Effects of the Layer Height and Exposure Energy on the Lateral Resolution of Zirconia Parts Printed by Lithography-Based Additive Manufacturing
Authors: Conti Laura , Bienenstein Daniel , Borlaf Mario , Graule Thomas
Published: March 2020

Lithography-based ceramics manufacturing (LCM) processes enable the sophisticated 3 dimensional (3D) shaping of ceramics by additive manufacturing (AM). The build-up occurs, like many other AM processes, layer by layer, and is initiated by light. The built-in digital mirror device (DMD) enables the specific exposure of desired pixels for every layer, giving as a consequence a first estimation of the printing resolution in the x and y axes. In this work, a commercial zirconia slurry and the CeraFab 7500, both from Lithoz GmbH (Vienna, Austria), were used to investigate the potential of reaching this resolution. The results showed that the precision of a part is strongly dependent on the applied exposure energy. Higher exposure energies resulted in oversized dimensions of a part, whereas too low energy was not able to guarantee the formation of a stable part. Furthermore, the investigation of the layer thickness showed that the applied exposure energy (mJ/cm2) was acting in a volume, and the impact is visible in x, y, and z dimensions. The lowest applied exposure energy was 83 mJ/cm2 and showed the most accurate results for a layer thickness of 25 μm. With this energy, holes and gaps smaller than 500 μm could be printed; however, the measurements differed significantly from the dimensions defined in the design. Holes and gaps larger than 500 μm showed deviations smaller than 50 μm from the design and could be printed reliably. The thinnest printable gaps were between 100 and 200 μm. Concerning the wall thickness, the experiments were conducted to a height of 1 cm. Taking into account the stability and deformation of the walls as well, the best results after sintering were achieved with thicknesses of 200–300 μm.
Penetration of Different Impression Materials into Exposed Dentinal Tubules during the Impression Procedure
Authors: Sinjari Bruna , D’Addazio Gianmaria , Xhajanka Edit , Caputi Sergio , Varvara Giuseppe , Traini Tonino
Published: March 2020

Adhesive restorations have been shown to guarantee excellent performance and longevity, although this comes with some disadvantages. Among these, the vulnerability of dentine to different agents has been widely evaluated. The aim of this study was to evaluate the possible penetration of impression materials into freshly cut dentine. Dentine from 27 teeth was impressed with polyether (Impregum Penta L) (nine teeth) and with polyvinyl siloxane (Aquasil Ultra LV) (nine teeth). The surface of nine teeth after the impressions were used as the control. Specifically, the extroflections caused by the imprinting of the dentinal tubules on the impression material, the so-called impression tags, were measured. Furthermore, the presence of the material inside the tubules was examined. Scanning electron microscopy analysis showed material tags for all of the experimental groups. The mean lengths (±SD) were 22.6 (±11.0) µm for polyether, 21.8 (±12.8) µm for polyvinyl siloxane and 11.3 (±7.0) µm for the tooth control, with mean diameters (±SD) of 2.8 (±0.5), 2.4 (±0.7) and 3.1 (±0.7) µm, respectively. Fractal analysis showed fractal dimensions of 1.78 (±0.03), 1.77 (±0.03) and 1.71 (±0.03), respectively. These data demonstrated that the impression materials can remain inside the dentinal tubules, which can adversely affect the adhesive procedures.
Study of the Effect of Titanium Dioxide Hydrosol on the Photocatalytic and Mechanical Properties of Paper Sheets
Authors: Toro Roberta Grazia , Diab Mohamed , de Caro Tilde , Al-Shemy Mona , Adel Abeer , Caschera Daniela
Published: March 2020

Different amounts of a stable aqueous TiO2 hydrosol were used to fabricate paper sheets having photocatalytic activity. The TiO2 hydrosol was prepared in aqueous medium using titanium butoxide as precursor and acetic acid as catalyst for the hydrolysis of titanium butoxide. An aging process at room temperature and atmospheric pressure was finally applied to obtain crystalline anatase TiO2 hydrosol. The effects of different TiO2 hydrosol loadings on the mechanical strength and barrier properties of modified paper sheets were investigated in detail. The photocatalytic behavior of TiO2-modified paper sheets was investigated as well using methylene blue (MB) as target pollutant.
Effects of Chip Type on the Properties of Chip–Sawdust Boards Glued with Polymeric Diphenyl Methane Diisocyanate
Authors: Mirski Radosław , Derkowski Adam , Dziurka Dorota , Wieruszewski Marek , Dukarska Dorota
Published: March 2020

This study investigates the effects of chip type and sawdust percentage on physical and mechanical properties of chip–sawdust boards. The used wood chips varied in linear dimensions and original source. The origin determined the wood quality, which translated into the chips’ linear dimensions. The used materials were chips from sawmill waste processing, aggregate processing of sawmill wood, and chips intended for medium-density boards. The experiment demonstrated that the best boards in terms of mechanical properties were obtained from 4-mm-thick chips with 30% sawdust content and a density of 850 kg/m3. These boards meet the requirements of the EN 312 (2010) standard for P5 boards.
Three-Dimensional Finite Element Analysis of the Undercut Anchor Group Effect in Rock Cone Failure
Authors: Jonak Józef , Siegmund Michał , Karpiński Robert , Wójcik Andrzej
Published: March 2020

An objective of this study was to investigate the group effect in rock cone failure occurring in pull-out with the use of 3D finite element analysis. At present, undercut anchors are typically applied as structural fasteners of steel elements in concrete buildings; however, new areas for their use are being explored. The reported study set out to evaluate the use of undercut anchors in special-purpose rock mining, e.g., in mining rescue operations. In such emergencies, mechanical mining may prove impossible, whereas the use of explosives is even prohibited. Although manual methods could be considered, their effectiveness is hard to assess. Prior to considering the use of undercut anchors in mining, several aspects must essentially be determined: The mechanics of cone failure, including the extent of surface failure and the values of the pull-out force of the anchor for a given rock mass relative to the anchor system, the embedment depth, or the rock strength parameters. These factors may be investigated successfully using finite element analysis, the results of which are presented in the study.
Numerical Simulation and Experiment of Electrically-Assisted Incremental Forming of Thin TC4 Titanium Alloy Sheet
Authors: Jiang Bo , Yang Wenbing , Zhang Ziyang , Li Xifeng , Ren Xueping , Wang Yaoqi
Published: March 2020

In order to integrally manufacture the large TC4 titanium alloy part, an electrically-assisted incremental forming process is cleverly proposed to solve the traditional hot forming disadvantages of expensive heating furnaces and long cycle period. The two-step simulation method including thermal-electricity coupling simulation and thermo-mechanical coupling simulation was selected to predict the temperature variations and the sheet deformation behaviors. The electrically-assisted incremental forming experiment of thin TC4 titanium alloy sheet was performed. The highest prediction error is 6% for springback angles. The thrice forming at 10.9 A/mm2 satisfies the precision requirement of the designed part. Therefore, the two-step simulation method can effectively calculate the electrically-assisted incremental process. The electrically-assisted incremental forming technique is very promising for the integral producing large titanium alloy part.
Strontium- and Cobalt-Doped Multicomponent Mesoporous Bioactive Glasses (MBGs) for Potential Use in Bone Tissue Engineering Applications
Authors: Kermani Farzad , Mollazadeh Beidokhti Sahar , Baino Francesco , Gholamzadeh-Virany Zahra , Mozafari Masoud , Kargozar Saeid
Published: March 2020

Mesoporous bioactive glasses (MBGs) offer suitable platforms for drug/ion delivery in tissue engineering strategies. The main goal of this study was to prepare strontium (Sr)- and cobalt (Co)-doped MBGs; strontium is currently used in the treatment of osteoporosis, and cobalt is known to exhibit pro-angiogenic effects. Sr- and Co-doped mesoporous glasses were synthesized for the first time in a multicomponent silicate system via the sol–gel method by using P123 as a structure-directing agent. The glassy state of the Sr- and Co-doped materials was confirmed by XRD before immersion in SBF, while an apatite-like layer was detected onto the surface of samples post-immersion. The textural characteristics of MBGs were confirmed by nitrogen adsorption/desorption measurements. In vitro experiments including MTT assay, Alizarin red staining, and cell attachment and migration showed the cytocompatibility of all the samples as well as their positive effects on osteoblast-like cell line MG-63. Early experiments with human umbilical vein endothelial cells also suggested the potential of these MBGs in the context of angiogenesis. In conclusion, the prepared materials were bioactive, showed the ability to improve osteoblast cell function in vitro and could be considered as valuable delivery vehicles for therapeutics, like Co2+ and Sr2+ ions.
‘Metal Complexes as Ligands’ for the Synthesis of Coordination Polymers: A MnIII Monomer as a Building Block for the Preparation of an Unprecedented 1-D {MnIIMnIII}n Linear Chain
Authors: Pantelis Konstantinos N. , Karotsis Georgios , Lampropoulos Christos , Cunha-Silva Luís , Escuer Albert , Stamatatos Theocharis C.
Published: March 2020

A relatively unexplored synthetic route in redox-active Mn(II/III) coordination chemistry has been employed toward the preparation of a new mixed-valence MnII/III 1-D linear chain from the reaction of [MnIII(sacb)2]− precursor with a MnII source, where sacbH2 is the Schiff base ligand N-salicylidene-2-amino-5-chlorobenzoic acid. The mononuclear (Pr2NH2)[MnIII(sacb)2] (1) compound was obtained in excellent yields (>85%) from the 1:2:3 reaction of Mn(O2CMe)2∙4H2O, sacbH2 and Pr2NH, respectively. In 1, the two doubly deprotonated sacb2− ligands act as Ocarboxylate,Nimine,Ophenoxide-tridentate chelates, while the second carboxylate O atom of sacb2− is dangling and H-bonded to the Pr2NH2+ countercation. Complex 1 was subsequently used as a ‘ligand’ to react stoichiometrically with the ‘metal’ Mn(NO3)2∙4H2O, thus leading to the 1-D coordination polymer {[MnIIMnIII(sacb)2(H2O)2(MeOH)2](NO3)}n (2) in good yields (~50%). The removal of Pr2NH2+ from the vicinity of the [MnIII(sacb)2]− metalloligand has rendered possible (vide infra) the coordination of the second Ocarboxylate of sacb2− to neighboring {MnII(H2O)2(MeOH)2}2+ units, and consequently the formation of the 1-D polymer 2. Direct-current (dc) magnetic susceptibility studies revealed the presence of very weak antiferromagnetic exchange interactions between alternating MnIII and MnII atoms with a coupling constant of J = −0.08 cm−1 for g = 2.00. The combined results demonstrate the potential of the ‘metal complexes as ligands’ approach to yield new mixed-valence Mn(II/III) coordination polymers with interesting structural motifs and physicochemical properties.
Influence of Nominal Maximum Aggregate Size and Aggregate Gradation on Pore Characteristics of Porous Asphalt Concrete
Authors: Huang Wenke , Cai Xu , Li Xiang , Cui Wentian , Wu Kuanghuai
Published: March 2020

Porous asphalt concrete (PAC) has been used to improve the traffic conditions in rainy weather due to its high porosity. Aggregate size and gradation have great impact on the connected pore structure, which ultimately affects the permeability of porous asphalt concrete. In this paper, the topological properties of connective pores including pore area, pore circularity, equivalent pore diameter, and void network of porous asphalt concrete with different nominal maximum aggregate sizes and gradations were analyzed using x-ray computer tomography scans and the image processing technique. It was observed that the maximum aggregate sizes will not have significant effect on the percentage of connected pores to total pores for porous asphalt concrete. Furthermore, the percentage of connected pores to total pores is related to the air void content, but for PAC-13 with 20% target air void content or above, the connectivity does not seem to have a sharp increase. Additionally, porous asphalt concrete with a smaller nominal particle size or lower target air void content seems to generate a more concentrated distribution of Eqdiameter. Moreover, pore circularities for porous asphalt concrete with a maximum aggregate size of 10 mm or above are independent of maximum aggregate sizes. Air void contents ranging from 16% to 21% do not have a significant effect on the voids’ circularity. Furthermore, the branching nodes in porous asphalt concrete with a smaller nominal maximum aggregate size or lower target air void content have a more uniform spatial distribution. However, the percentage of cross-linked number to total node raises as the nominal maximum aggregate size or target air void content increases.
Experimental Study on Distribution of Landslide Thrust in Pile-Anchor Structure based on Photoelastic Technique
Authors: Li Xunchang , Xu Rui , Yang Wei , Li Pingan , Yang Ke , Zhang Wenyong
Published: March 2020

This paper aimed to perform systematical study on the distribution of landslide thrust in pile-anchor support system, which has been a widely applicable treatment method in landslide control with safety, highly efficiency and adaptation. The advantage of photoelastic technique is visualization of strain and stress fields, therefore photoelastic model tests are conducted to show the distribution of landslide thrust in pile-anchor structure before failure in landslide. The effects of different materials and pile lengths are investigated by 6 photoelastic test cases under different loading conditions. It can be found from quantitative analysis of experimental results that load proportion of anchor would increase gradually with the decrease of pile embedded depth or the increase of landslide thrust force. Meanwhile, landslide thrust distribution in pile-anchor structure is directly affected by the stiffness of piles. The pile-anchor structure is significantly better at reducing bending moment value and optimizing bending moment distribution of pile. Finally, some theoretical analysis and design suggestions are proposed based on the experimental study.
Modifications of the HJC (Holmquist–Johnson–Cook) Model for an Improved Numerical Simulation of Roller Compacted Concrete (RCC) Structures Subjected to Impact Loadings
Authors: Wang Chao , Song Ran , Wang Gaohui , Zhang Sherong , Cao Xuexing , Wei Peiyong
Published: March 2020

Structures made of Roller Compacted Concrete (RCC) may be subjected to dynamic loads during their service life. Understanding the dynamic material properties of RCC and the performance of RCC structures is essential for better analysis and design of RCC structures. As full-scale tests are often unaffordable, numerical simulation methods are continuously employed. However, in numerical simulations, determining a reasonable constitutive relationship for RCC materials is still limited due to the complexity of the composite and the special rolling and compacting construction technology. In this paper, the triaxial compressive test and split Hopkinson pressure bar (SHPB) experimental results for RCC are introduced as an experimental foundation. Parameter calibrations and modifications in terms of the strength yield surface, the strain rate effect and the failure criterion for the RCC materials are presented. Numerical verification is illustrated for simulating the SHPB experiment and predicting the dynamic compressive characteristics of RCC specimens with a modified HJC model. The results reveal that the simulation results for the modified model have better agreement with the test data than those with the model before modification and have better simulation results. Sensitivity studies of the key parameters on the yield surface of the modified HJC model are conducted to improve the simulation effect for numerically predicting the performance of RCC structures exposed to explosive and impact loads.
Human Milk Oligosaccharide Profile Variation Throughout Postpartum in Healthy Women in a Brazilian Cohort
Authors: Ferreira Ana Lorena , Alves Ronaldo , Figueiredo Amanda , Alves-Santos Nadya , Freitas-Costa Nathalia , Batalha Mônica , Yonemitsu Chloe , Manivong Nadia , Furst Annalee , Bode Lars , Kac Gilberto
Published: March 2020

Human milk oligosaccharide (HMO) composition varies throughout lactation and can be influenced by maternal characteristics. This study describes HMO variation up to three months postpartum and explores the influences of maternal sociodemographic and anthropometric characteristics in a Brazilian prospective cohort. We followed 101 subjects from 28–35 gestational weeks (baseline) and throughout lactation at 2–8 (visit 1), 28–50 (visit 2) and 88–119 days postpartum (visit 3). Milk samples were collected at visits 1, 2 and 3, and 19 HMOs were quantified usinghigh-performance liquid chromatography with fluorescence detection (HPLC-FL). Friedman post-hoc test, Spearman rank correlation for maternal characteristics and HMOs and non-negative matrix factorization (NMF) were used to define the HMO profile. Most women were secretors (89.1%) and presented high proportion of 2′-fucosyllactose (2′FL) at all three sample times, while lacto-N-tetraose (LNT, 2–8 days) and lacto-N-fucopentaose II (LNFPII, 28–50 and 88–119 days) were the most abundant HMOs in non-secretor women. Over the course of lactation, total HMO weight concentrations (g/L) decreased, but total HMO molar concentrations (mmol/L) increased, highlighting differential changes in HMO composition over time. In addition, maternal pre-pregnancy body mass index (BMI) and parity influence the HMO composition in healthy women in this Brazilian cohort.