bluuebunny/crossref_metadata_2025 huggingface dataset:
Epigenetic Regulation of Circadian Rhythm and Its Possible Role in Diabetes Mellitus
Authors: Hudec Michael , Dankova Pavlina , Solc Roman , Bettazova Nardjas , Cerna Marie
Published: April 2020

This review aims to summarize the knowledge about the relationship between circadian rhythms and their influence on the development of type 2 diabetes mellitus (T2DM) and metabolic syndrome. Circadian rhythms are controlled by internal molecular feedback loops that synchronize the organism with the external environment. These loops are affected by genetic and epigenetic factors. Genetic factors include polymorphisms and mutations of circadian genes. The expression of circadian genes is regulated by epigenetic mechanisms that change from prenatal development to old age. Epigenetic modifications are influenced by the external environment. Most of these modifications are affected by our own life style. Irregular circadian rhythm and low quality of sleep have been shown to increase the risk of developing T2DM and other metabolic disorders. Here, we attempt to provide a wide description of mutual relationships between epigenetic regulation, circadian rhythm, aging process and highlight new evidences that show possible therapeutic advance in the field of chrono-medicine which will be more important in the upcoming years.
Transcriptomic Profiling of Circular RNA in Different Brain Regions of Parkinson’s Disease in a Mouse Model
Authors: Jia Erteng , Zhou Ying , Liu Zhiyu , Wang Liujing , Ouyang Tinglan , Pan Min , Bai Yunfei , Ge Qinyu
Published: April 2020

Parkinson’s disease (PD) is the second most common neurodegenerative disease and although many studies have been done on this disease, the underlying mechanisms are still poorly understood and further studies are warranted. Therefore, this study identified circRNA expression profiles in the cerebral cortex (CC), hippocampus (HP), striatum (ST), and cerebellum (CB) regions of the 1-methyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mouse model using RNA sequencing (RNA-seq), and differentially expressed circRNA were validated using reverse transcription quantitative real-time PCR (qRT-PCR). Gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway, and competing endogenous RNA (ceRNA) network analyses were also performed to explore the potential function of circRNAs. The results show that, compared with the control group, 24, 66, 71, and 121 differentially expressed circRNAs (DE-circRNAs) were found in the CC, HP, ST, and CB, respectively. PDST vs. PDCB, PDST vs. PDHP, and PDCB vs. PDHP groups have 578, 110, and 749 DE-circRNAs, respectively. Then, seven DE-cirRNAs were selected for qRT-PCR verification, where the expressions were consistent with the sequencing analysis. The GO and KEGG pathway analyses revealed that these DE-circRNAs participate in several biological functions and signaling pathways, including glutamic synapse, neuron to neuron synapse, cell morphogenesis involved in neuron differentiation, Parkinson’s disease, axon guidance, cGMP-PKG signaling pathway, and PI3K-Akt signaling pathway. Furthermore, the KEGG analysis of the target genes predicted by DE-circRNAs indicated that the target genes predicted by mmu_circRNA_0003292, mmu_circRNA_0001320, mmu_circRNA_0005976, and mmu_circRNA_0005388 were involved in the PD-related pathway. Overall, this is the first study on the expression profile of circRNAs in the different brain regions of PD mouse model. These results might facilitate our understanding of the potential roles of circRNAs in the pathogenesis of PD. Moreover, the results also indicate that the mmu_circRNA_0003292-miRNA-132-Nr4a2 pathway might be involved in the regulation of the molecular mechanism of Parkinson’s disease.
MfPIF1 of Resurrection Plant Myrothamnus flabellifolia Plays a Positive Regulatory Role in Responding to Drought and Salinity Stresses in Arabidopsis
Authors: Qiu Jia-Rui , Xiang Xiang-Ying , Wang Jia-Tong , Xu Wen-Xin , Chen Jia , Xiao Yao , Jiang Cai-Zhong , Huang Zhuo
Published: April 2020

Phytochrome-interacting factors (PIFs), a subfamily of basic helix-loop-helix (bHLH) transcription factors (TFs), play critical roles in regulating plant growth and development. The resurrection plant Myrothamnus flabellifolia possesses a noteworthy tolerance to desiccation, but no PIFs related to the response to abiotic stress have been functionally studied. In this study, a dehydration-inducible PIF gene, MfPIF1, was cloned and characterized. Subcellular localization assay revealed that MfPIF1 is localized predominantly in the nucleus. Overexpression of MfPIF1 in Arabidopsis thaliana led to enhanced drought and salinity tolerance, which was attributed to higher contents of chlorophyll, proline (Pro), soluble protein, and soluble sugar, activities of antioxidant enzymes as well as lower water loss rate, malondialdehyde (MDA) content, and reactive oxygen species (ROS) accumulation in transgenic lines compared with control plants. Moreover, MfPIF1 decreased stomatal aperture after drought and abscisic acid (ABA) treatment, and increased expression of both ABA biosynthesis and ABA-responsive genes including NCED3, P5CS, and RD29A. Overall, these results indicated that MfPIF1 may act as a positive regulator to drought and salinity responses, and therefore could be considered as a potential gene for plant genetic improvement of drought and salinity tolerance.
Thermogenesis in Adipose Tissue Activated by Thyroid Hormone
Authors: Yau Winifred W. , Yen Paul M.
Published: April 2020

Thermogenesis is the production of heat that occurs in all warm-blooded animals. During cold exposure, there is obligatory thermogenesis derived from body metabolism as well as adaptive thermogenesis through shivering and non-shivering mechanisms. The latter mainly occurs in brown adipose tissue (BAT) and muscle; however, white adipose tissue (WAT) also can undergo browning via adrenergic stimulation to acquire thermogenic potential. Thyroid hormone (TH) also exerts profound effects on thermoregulation, as decreased body temperature and increased body temperature occur during hypothyroidism and hyperthyroidism, respectively. We have termed the TH-mediated thermogenesis under thermoneutral conditions “activated” thermogenesis. TH acts on the brown and/or white adipose tissues to induce uncoupled respiration through the induction of the uncoupling protein (Ucp1) to generate heat. TH acts centrally to activate the BAT and browning through the sympathetic nervous system. However, recent studies also show that TH acts peripherally on the BAT to directly stimulate Ucp1 expression and thermogenesis through an autophagy-dependent mechanism. Additionally, THs can exert Ucp1-independent effects on thermogenesis, most likely through activation of exothermic metabolic pathways. This review summarizes thermogenic effects of THs on adipose tissues.
The EDCMET Project: Metabolic Effects of Endocrine Disruptors
Authors: Küblbeck Jenni , Vuorio Taina , Niskanen Jonna , Fortino Vittorio , Braeuning Albert , Abass Khaled , Rautio Arja , Hakkola Jukka , Honkakoski Paavo , Levonen Anna-Liisa
Published: April 2020

Endocrine disruptors (EDs) are defined as chemicals that mimic, block, or interfere with hormones in the body’s endocrine systems and have been associated with a diverse array of health issues. The concept of endocrine disruption has recently been extended to metabolic alterations that may result in diseases, such as obesity, diabetes, and fatty liver disease, and constitute an increasing health concern worldwide. However, while epidemiological and experimental data on the close association of EDs and adverse metabolic effects are mounting, predictive methods and models to evaluate the detailed mechanisms and pathways behind these observed effects are lacking, thus restricting the regulatory risk assessment of EDs. The EDCMET (Metabolic effects of Endocrine Disrupting Chemicals: novel testing METhods and adverse outcome pathways) project brings together systems toxicologists; experimental biologists with a thorough understanding of the molecular mechanisms of metabolic disease and comprehensive in vitro and in vivo methodological skills; and, ultimately, epidemiologists linking environmental exposure to adverse metabolic outcomes. During its 5-year journey, EDCMET aims to identify novel ED mechanisms of action, to generate (pre)validated test methods to assess the metabolic effects of Eds, and to predict emergent adverse biological phenotypes by following the adverse outcome pathway (AOP) paradigm.
Role of Bone Targeting Agents in the Prevention of Bone Metastases from Breast Cancer
Authors: D’Oronzo Stella , Silvestris Erica , Paradiso Angelo , Cives Mauro , Tucci Marco
Published: April 2020

Breast cancer (BC) is the most common malignancy in women worldwide and leads, in more than 70% of patients with advanced disease, to skeleton colonization and formation of bone metastases (BM). This condition implies a severe disability and deterioration of the quality of life, with consequent additional social costs. In recent decades, several studies explored the role of agents acting within the bone microenvironment to counteract BM development, and several bone-targeting agents (BTAs) have been introduced in the clinical practice to manage bone lesions and reduce the risk of skeletal complications. However, long-term exposure to these agents is not free from potential toxicities and needs careful monitoring. In this context, the potential capability to prevent BM onset in selected BC patients, through the early administration of BTAs, has been explored by several researchers, with the belief that “prevention is better than cure” and that, ultimately, metastatic BC is an incurable condition. Here, we revised the mechanisms of BM development in BC as well as the strategies for selecting high-risk patients suitable for early BTA treatment.
Potential Use of Extracellular Vesicles Generated by Microbubble-Assisted Ultrasound as Drug Nanocarriers for Cancer Treatment
Authors: Yuana Yuana , Balachandran Banuja , van der Wurff-Jacobs Kim M. G. , Schiffelers Raymond M. , Moonen Chrit T.
Published: April 2020

Extracellular vesicles (EVs)-carrying biomolecules derived from parental cells have achieved substantial scientific interest for their potential use as drug nanocarriers. Ultrasound (US) in combination with microbubbles (MB) have been shown to trigger the release of EVs from cancer cells. In the current study, the use of microbubbles-assisted ultrasound (USMB) to generate EVs containing drug cargo was investigated. The model drug, CellTracker™ green fluorescent dye (CTG) or bovine serum albumin conjugated with fluorescein isothiocyanate (BSA FITC) was loaded into primary human endothelial cells in vitro using USMB. We found that USMB loaded CTG and BSA FITC into human endothelial cells (HUVECs) and triggered the release of EVs containing these compounds in the cell supernatant within 2 h after treatment. The amount of EV released seemed to be correlated with the increase of US acoustic pressure. Co-culturing these EVs resulted in uptake by the recipient tumour cells within 4 h. In conclusion, USMB was able to load the model drugs into endothelial cells and simultaneously trigger the release of EVs-carrying model drugs, highlighting the potential of EVs as drug nanocarriers for future drug delivery in cancer.
Correlation of RAS-Pathway Mutations and Spontaneous Myeloid Colony Growth with Progression and Transformation in Chronic Myelomonocytic Leukemia—A Retrospective Analysis in 337 Patients
Authors: Geissler Klaus , Jäger Eva , Barna Agnes , Gurbisz Michael , Graf Temeida , Graf Elmir , Nösslinger Thomas , Pfeilstöcker Michael , Tüchler Heinz , Sliwa Thamer , Keil Felix , Geissler Christoph , Heibl Sonja , Thaler Josef , Machherndl-Spandl Sigrid , Zach Otto , Weltermann Ansgar , Bettelheim Peter , Stauder Reinhard , Zebisch Armin , Sill Heinz , Schwarzinger Ilse , Schneeweiss Bruno , Öhler Leopold , Ulsperger Ernst , Kusec Rajko , Germing Ulrich , Sperr Wolfgang R. , Knöbl Paul , Jäger Ulrich , Hörmann Gregor , Valent Peter
Published: April 2020

Although the RAS-pathway has been implicated as an important driver in the pathogenesis of chronic myelomonocytic leukemia (CMML) a comprehensive study including molecular and functional analyses in patients with progression and transformation has not been performed. A close correlation between RASopathy gene mutations and spontaneous in vitro myeloid colony (CFU-GM) growth in CMML has been described. Molecular and/or functional analyses were performed in three cohorts of 337 CMML patients: in patients without (A, n = 236) and with (B, n = 61) progression/transformation during follow-up, and in patients already transformed at the time of sampling (C, n = 40 + 26 who were before in B). The frequencies of RAS-pathway mutations (variant allele frequency ≥ 20%) in cohorts A, B, and C were 30%, 47%, and 71% (p < 0.0001), and of high colony growth (≥20/105 peripheral blood mononuclear cells) 31%, 44%, and 80% (p < 0.0001), respectively. Increases in allele burden of RAS-pathway mutations and in numbers of spontaneously formed CFU-GM before and after transformation could be shown in individual patients. Finally, the presence of mutations in RASopathy genes as well as the presence of high colony growth prior to transformation was significantly associated with an increased risk of acute myeloid leukemia (AML) development. Together, RAS-pathway mutations in CMML correlate with an augmented autonomous expansion of neoplastic precursor cells and indicate an increased risk of AML development which may be relevant for targeted treatment strategies.
Promiscuous Roles of Autophagy and Proteasome in Neurodegenerative Proteinopathies
Authors: Limanaqi Fiona , Biagioni Francesca , Gambardella Stefano , Familiari Pietro , Frati Alessandro , Fornai Francesco
Published: April 2020

Alterations in autophagy and the ubiquitin proteasome system (UPS) are commonly implicated in protein aggregation and toxicity which manifest in a number of neurological disorders. In fact, both UPS and autophagy alterations are bound to the aggregation, spreading and toxicity of the so-called prionoid proteins, including alpha synuclein (α-syn), amyloid-beta (Aβ), tau, huntingtin, superoxide dismutase-1 (SOD-1), TAR-DNA-binding protein of 43 kDa (TDP-43) and fused in sarcoma (FUS). Recent biochemical and morphological studies add to this scenario, focusing on the coordinated, either synergistic or compensatory, interplay that occurs between autophagy and the UPS. In fact, a number of biochemical pathways such as mammalian target of rapamycin (mTOR), transcription factor EB (TFEB), Bcl2-associated athanogene 1/3 (BAG3/1) and glycogen synthase kinase beta (GSk3β), which are widely explored as potential targets in neurodegenerative proteinopathies, operate at the crossroad between autophagy and UPS. These biochemical steps are key in orchestrating the specificity and magnitude of the two degradation systems for effective protein homeostasis, while intermingling with intracellular secretory/trafficking and inflammatory pathways. The findings discussed in the present manuscript are supposed to add novel viewpoints which may further enrich our insight on the complex interactions occurring between cell-clearing systems, protein misfolding and propagation. Discovering novel mechanisms enabling a cross-talk between the UPS and autophagy is expected to provide novel potential molecular targets in proteinopathies.
Validation of Hyponatremia as a Prognostic Predictor in Multiregional Upper Tract Urothelial Carcinoma
Authors: Yeh Hsin-Chih , Li Ching-Chia , Wen Sheng-Chen , Singla Nirmish , Woldu Solomon L. , Robyak Haley , Huang Chun-Nung , Ke Hung-Lung , Li Wei-Ming , Lee Hsiang-Ying , Li Chia-Yang , Yeh Bi-Wen , Yang Sheau-Fang , Tu Hung-Pin , Shariat Shahrokh F. , Sagalowsky Arthur I. , Raman Jay D. , Lotan Yair , Hsieh Jer-Tsong , Margulis Vitaly , Wu Wen-Jeng
Published: April 2020

Hyponatremia has been shown to be associated with prognosis in various cancers, but its role in upper tract urothelial carcinoma (UTUC) is largely unidentified. We created an international multiregional cohort of UTUC, consisting of 524 and 213 patients from Taiwan and the U.S., to validate the significance of hyponatremia. Clinicopathologic characteristics were compared according to the presence of hyponatremia. Univariate and multivariate Cox regression models were used to investigate the association of hyponatremia with disease progression and survival. The impact of hyponatremia in patients from distinct regions was also analyzed. Hyponatremia was found in 143 (19.4%) patients. Hyponatremic patients had significantly worse Eastern Cooperative Oncology Group (ECOG) performance status (p = 0.00001) and higher pT stage (p = 0.002). In multivariate analysis, hyponatremia was an independent prognostic factor for progression (HR 1.585, 95% CI 1.115–2.253, p = 0.010), cancer-specific death (HR 2.225, 95% CI 1.457–3.397, p = 0.0002), and overall mortality (HR 1.819, 95% CI 1.299–2.545, p = 0.0005). Kaplan–Meier analysis showed the consistent adverse effect of hyponatremia on all outcomes in patients from Taiwan and the U.S. (all p < 0.05). Hyponatremia is commonly accessible and can serve as a negative marker for both the general health condition and disease severity of UTUC patients. A similar implication of hyponatremia in progression and survival despite patients’ region of presentation suggests its general applicability across different ethnicities.
Effects of Marine Exhaust Gas Scrubbers on Gas and Particle Emissions
Authors: Winnes Hulda , Fridell Erik , Moldanová Jana
Published: April 2020

There is an increase in installations of exhaust gas scrubbers on ships following international regulations on sulphur content in marine fuel from 2020. We have conducted emission measurements on a four-stroke marine engine using low sulphur fuel oil (LSFO) and heavy fuel oil (HFO) at different steady state engine loads. For the HFO the exhaust was probed upstream and downstream of an exhaust gas scrubber. While sulphur dioxide was removed with high efficiency in the scrubber, the measurements of particle emissions indicate lower emissions at the use of LSFO than downstream of the scrubber. The scrubber removes between 32% and 43% of the particle mass from the exhaust at the HFO tests upstream and downstream of the scrubber, but levels equivalent to those in LSFO exhaust are not reached. Decreases in the emissions of polycyclic aromatic hydrocarbons (PAH-16) and particulate matter as black carbon, organic carbon and elemental carbon, over the scrubber were observed for a majority of the trials, although emissions at LSFO use were consistently lower at comparable engine power.
Dynamic Transmissions and Volatility Spillovers between Global Price and U.S. Producer Price in Agricultural Markets
Authors: Guo Jin , Tanaka Tetsuji
Published: April 2020

A considerable number of studies have examined the relationship between global prices and local prices in food-importing nations, but the linkages between international prices and the producer prices of large agricultural exporters have been largely ignored. This paper analyzes the connections between world prices and U.S. producer prices in the wheat, soybeans, and corn markets using a vector error correction generalized autoregressive conditional heteroscedastic model with a multivariate Baba-Engle-Kraft Kroner specification (VECM-GARCH-BEKK) and cross-correlation function (CCF). Our findings indicate firstly that a long-run equilibrium relationship exists between international and U.S. producer prices for the three agricultural crops. It also finds a significant bidirectional causality-in-mean and causality-in-variance between international and U.S. producer prices for these crops. Finally, the empirical results suggest that international wheat and corn prices play a leading role in U.S. local markets in return transmissions and that U.S. wheat price can be considered to be a leading indicator of the global wheat price in volatility transmissions.
Refined Measures of Dynamic Connectedness based on Time-Varying Parameter Vector Autoregressions
Authors: Antonakakis Nikolaos , Chatziantoniou Ioannis , Gabauer David
Published: April 2020

In this study, we enhance the dynamic connectedness measures originally introduced by Diebold and Yılmaz (2012, 2014) with a time-varying parameter vector autoregressive model (TVP-VAR) which predicates upon a time-varying variance-covariance structure. This framework allows to capture possible changes in the underlying structure of the data in a more flexible and robust manner. Specifically, there is neither a need to arbitrarily set the rolling-window size nor a loss of observations in the calculation of the dynamic measures of connectedness, as no rolling-window analysis is involved. Given that the proposed framework rests on multivariate Kalman filters, it is less sensitive to outliers. Furthermore, we emphasise the merits of this approach by conducting Monte Carlo simulations. We put our framework into practice by investigating dynamic connectedness measures of the four most traded foreign exchange rates, comparing the TVP-VAR results to those obtained from three different rolling-window settings. Finally, we propose uncertainty measures for both TVP-VAR-based and rolling-window VAR-based dynamic connectedness measures.
Inclusive Landscape Governance for Sustainable Development: Assessment Methodology and Lessons for Civil Society Organizations
Authors: Kusters Koen , De Graaf Maartje , Buck Louise , Galido Katherine , Maindo Alphonse , Mendoza Heidi , Nghi Tran , Purwanto Edi , Zagt Roderick
Published: April 2020

Landscape governance refers to the combination of rules and decision-making processes of civic, private, and public actors with stakes in the landscape, that together shape the future of that landscape. As part of the Green Livelihoods Alliance, a program that supports civil society organizations (CSOs) to strengthen the governance of tropical forested landscapes, we developed and implemented a method that facilitates stakeholders to assess the status of governance in their own landscape and to identify options for improvement. In this article, we aim to reflect on landscape governance, based on our work within the Green Livelihoods Alliance. We present the method, summarize the results of its implementation, and draw practical lessons regarding the role of CSOs to improve landscape governance. We conducted workshops with stakeholders in 17 forested landscapes across 10 countries in Asia, Africa, and Latin America. During each workshop, participants scored and discussed a set of governance indicators, developed a common vision for landscape governance, and identified the practical steps that would need to be taken to achieve that vision. Analyzing the results from the workshops, we found that landscape stakeholders tend to perceive that: opportunities to influence decision-making are unequal; integrated landscape planning efforts remain noncommittal; and implementation and enforcement of regulations is weak. To improve governance in the future, it is common to call for the development of multi-stakeholder processes, to allow different actors to discuss, negotiate, and develop collaborative action to address landscape-level challenges. CSOs can support such processes, by helping to develop a shared understanding of landscape governance, differences in interests, and possibilities for collaborative action. CSOs can also help stakeholders to develop multi-stakeholder procedures, and build trust and capacity among stakeholders to take an active role in such processes.
High Temperature Microtribological Studies of MoS2 Lubrication for Low Earth Orbit
Authors: Serles Peter , Gaber Khaled , Pajovic Simo , Colas Guillaume , Filleter Tobin
Published: April 2020

Molybdenum disulfide is one of the most common lubricant coatings for space systems but it displays enormous susceptibility to environmental conditions making it hard to predict performance throughout the entire lifetime. The majority of mechanisms for space operate in low Earth orbit where temperatures typically reach 120 °C along with exposure to highly reactive atomic oxygen which can be detrimental to lubricant performance. In the present study, a MoS2 lubricant coating is tested using friction force microscopy under different environmental conditions including air and dry nitrogen environments with temperatures ranging from 25 °C to 120 °C. The increased temperature was found to be beneficial for friction behaviour in air up to 100 °C as ambient humidity is removed from the contact, but higher temperatures become detrimental as increased reactivity leads to oxidation. These competing effects resulted in a minimum coefficient of friction at 110 °C in the air environment. The high temperature also increases the wear of the coatings as the intrinsic shear strength decreases with thermal energy which in turn disrupts tribofilm formation leading to increased friction. The run-in duration and magnitude are both found to decrease with temperature as the energy barrier to optimal reconfiguration is reduced. Finally, contextualization of the present findings for mechanisms operating in low earth orbit is discussed.
Electronic and Crystallographic Examinations of the Homoepitaxially Grown Rubrene Single Crystals
Authors: Nakayama Yasuo , Iwashita Masaki , Kikuchi Mitsuru , Tsuruta Ryohei , Yoshida Koki , Gunjo Yuki , Yabara Yusuke , Hosokai Takuya , Koganezawa Tomoyuki , Izawa Seiichiro , Hiramoto Masahiro
Published: April 2020

Homoepitaxial growth of organic semiconductor single crystals is a promising methodology toward the establishment of doping technology for organic opto-electronic applications. In this study, both electronic and crystallographic properties of homoepitaxially grown single crystals of rubrene were accurately examined. Undistorted lattice structures of homoepitaxial rubrene were confirmed by high-resolution analyses of grazing-incidence X-ray diffraction (GIXD) using synchrotron radiation. Upon bulk doping of acceptor molecules into the homoepitaxial single crystals of rubrene, highly sensitive photoelectron yield spectroscopy (PYS) measurements unveiled a transition of the electronic states, from induction of hole states at the valence band maximum at an adequate doping ratio (10 ppm), to disturbance of the valence band itself for excessive ratios (≥ 1000 ppm), probably due to the lattice distortion.
Residual Compressive Strength of Recycled Aggregate Concretes after High Temperature Exposure
Authors: Varona Francisco B. , Baeza-Brotons Francisco , Tenza-Abril Antonio J. , Baeza F. Javier , Bañón Luis
Published: April 2020

Sustainability requirements are gaining importance in the construction industry, which needs to take specific measures in the design and construction of concrete structures. The use of recycled aggregates in concrete may be of special interest. Recycling a construction waste will close the life cycle of the original materials (e.g., concrete). Thus, environmental benefits would come from the lower waste generation, and from a lower necessity of raw materials for new structures. The current Spanish code for structural concrete considers the use of recycled aggregates in replacement rates up to 20% by aggregate mass, assimilating their properties with those of concretes without aggregate replacement. Higher substitution percentages would require further testing. In this work, substitution of coarse aggregate for recycled aggregates (with replacement percentages of 25%, 50% and 100%) has been studied, and the concrete’s residual properties after exposure to high temperatures (between 350 °C and 850 °C) have been assessed. Compressive strength and capillary water absorption tests were made after heating, and the experiments showed higher residual strength in concretes with the greatest content of recycled aggregates. However, a statistical analysis made with additional data available in the literature seemed to predict otherwise, and the recycled aggregate replacement would have a negative effect on the residual strength.
Nonlinear Buckling Behavior of Spiral Corrugated Sandwich FGM Cylindrical Shells Surrounded by an Elastic Medium
Authors: Tho Hung Vu , Thuy Dong Dang , Thi Phuong Nguyen , Ngoc Ly Le , Quang Minh Tran , Trung Nguyen-Thoi , Hoai Nam Vu
Published: April 2020

This paper presents a semi-analytical approach for investigating the nonlinear buckling and postbuckling of spiral corrugated sandwich functionally graded (FGM) cylindrical shells under external pressure and surrounded by a two-parameter elastic foundation based on Donnell shell theory. The improved homogenization theory for the spiral corrugated FGM structure is applied and the geometrical nonlinearity in a von Karman sense is taken into account. The nonlinear equilibrium equation system can be solved by using the Galerkin method with the three-term solution form of deflection. An explicit solution form for the nonlinear buckling behavior of shells is obtained. The critical buckling pressure and the postbuckling strength of shells are numerically investigated. Additionally, the effects of spiral corrugation in enhancing the nonlinear buckling behavior of spiral corrugated sandwich FGM cylindrical shells are validated and discussed.
High Functionality Bio-Polyols from Tall Oil and Rigid Polyurethane Foams Formulated Solely Using Bio-Polyols
Authors: Kirpluks Mikelis , Vanags Edgars , Abolins Arnis , Michalowski Slawomir , Fridrihsone Anda , Cabulis Ugis
Published: April 2020

High-quality rigid polyurethane (PU) foam thermal insulation material has been developed solely using bio-polyols synthesized from second-generation bio-based feedstock. High functionality bio-polyols were synthesized from cellulose production side stream—tall oil fatty acids by oxirane ring-opening as well as esterification reactions with different polyfunctional alcohols, such as diethylene glycol, trimethylolpropane, triethanolamine, and diethanolamine. Four different high functionality bio-polyols were combined with bio-polyol obtained from tall oil esterification with triethanolamine to develop rigid PU foam formulations applicable as thermal insulation material. The developed formulations were optimized using response surface modeling to find optimal bio-polyol and physical blowing agent: c-pentane content. The optimized bio-based rigid PU foam formulations delivered comparable thermal insulation properties to the petro-chemical alternative.
Analytical Thermal Modeling of Powder Bed Metal Additive Manufacturing Considering Powder Size Variation and Packing
Authors: Ning Jinqiang , Wang Wenjia , Ning Xuan , Sievers Daniel E. , Garmestani Hamid , Liang Steven Y.
Published: April 2020

This work presents a computationally efficient predictive model based on solid heat transfer for temperature profiles in powder bed metal additive manufacturing (PBMAM) considering the heat transfer boundary condition and powder material properties. A point moving heat source model is used for the three-dimensional temperature prediction in an absolute coordinate. The heat loss from convection and radiation is calculated using a heat sink solution with a mathematically discretized boundary considering non-uniform temperatures and heat loss at the boundary. Powder material properties are calculated considering powder size statistical distribution and powder packing. The spatially uniform and temperature-independent material properties are employed in the temperature prediction. The presented model was tested in PBMAM of AlSi10Mg under different process conditions. The calculations of material properties are needed for AlSi10Mg because of the significant difference in thermal conductivity between powder form and solid bulk form. Close agreement is observed upon experimental validation on the molten pool dimensions.
CuSCN as the Back Contact for Efficient ZMO/CdTe Solar Cells
Authors: Li Deng-Bing , Song Zhaoning , Bista Sandip S. , Alfadhili Fadhil K. , Awni Rasha A. , Shrestha Niraj , Rhiannon DeMilt , Phillips Adam B. , Heben Michael J. , Ellingson Randy J. , Yan Feng , Yan Yanfa
Published: April 2020

The replacement of traditional CdS with zinc magnesium oxide (ZMO) has been demonstrated as being helpful to boost power conversion efficiency of cadmium telluride (CdTe) solar cells to over 18%, due to the reduced interface recombination and parasitic light absorption by the buffer layer. However, due to the atmosphere sensitivity of ZMO film, the post treatments of ZMO/CdTe stacks, including CdCl2 treatment, back contact deposition, etc., which are critical for high-performance CdTe solar cells became crucial challenges. To realize the full potential of the ZMO buffer layer, plenty of investigations need to be accomplished. Here, copper thiocyanate (CuSCN) is demonstrated to be a suitable back-contact material with multi-advantages for ZMO/CdTe solar cells. Particularly, ammonium hydroxide as the solvent for CuSCN deposition shows no detrimental impact on the ZMO layer during the post heat treatment. The post annealing temperature as well as the thickness of CuSCN films are investigated. Finally, a champion power conversion efficiency of 16.7% is achieved with an open-circuit voltage of 0.857 V, a short-circuit current density of 26.2 mA/cm2, and a fill factor of 74.0%.
Bone Regeneration in Critical-Sized Bone Defects Treated with Additively Manufactured Porous Metallic Biomaterials: The Effects of Inelastic Mechanical Properties
Authors: Koolen Marianne , Amin Yavari Saber , Lietaert Karel , Wauthle Ruben , Zadpoor Amir A. , Weinans Harrie
Published: April 2020

Additively manufactured (AM) porous metallic biomaterials, in general, and AM porous titanium, in particular, have recently emerged as promising candidates for bone substitution. The porous design of such materials allows for mimicking the elastic mechanical properties of native bone tissue and showed to be effective in improving bone regeneration. It is, however, not clear what role the other mechanical properties of the bulk material such as ductility play in the performance of such biomaterials. In this study, we compared the bone tissue regeneration performance of AM porous biomaterials made from the commonly used titanium alloy Ti6Al4V-ELI with that of commercially pure titanium (CP-Ti). CP-Ti was selected because of its high ductility as compared to Ti6Al4V-ELI. Critical-sized (6 mm diameter) femoral defects in rats were treated with implants made from both Ti6Al4V-ELI and CP-Ti. Bone regeneration was assessed up to 11 weeks using micro-CT scanning. The regenerated bone volume was assessed ex vivo followed by histology and biomechanical testing to assess osseointegration of the implants. The bony defects treated with AM CP-Ti implants generally showed higher volumes of regenerated bone as compared to those treated with AM Ti6Al4V-ELI. The torsional strength of the two titanium groups were similar however, and both considerably lower than those measured for intact bony tissue. These findings show the importance of material type and ductility of the bulk material in the ability for bone tissue regeneration of AM porous biomaterials.
Biphenyl Wrinkled Mesoporous Silica Nanoparticles for pH-Responsive Doxorubicin Drug Delivery
Authors: Lin Jason , Peng Chuanqi , Ravi Sanjana , Siddiki A. K. M. Nur Alam , Zheng Jie , Balkus Kenneth J.
Published: April 2020

Biphenyl wrinkled mesoporous silica nanoparticles with controlled particle size and high surface area were evaluated for the storage and delivery of doxorubicin. The average particle size and surface area were ~70 nm and ~1100 m2/g. The doxorubicin loading efficiency was 38.2 ± 1.5 (w/w)% and the release was pH dependent. The breast cancer cell line, MCF-7 (Michigan Cancer Foundation-7) was used for the in vitro drug release study. The cytotoxicity of doxorubicin-loaded nanoparticles was significantly higher than free doxorubicin. Fluorescence images showed biphenyl wrinkled mesoporous silica (BPWS) uptake by the MCF-7 cells. The biphenyl bridged wrinkled silica nanoparticles appear promising for hydrophobic drug loading and delivery.
Impact of Laser Structuring on Medical-Grade Titanium: Surface Characterization and In Vitro Evaluation of Osteoblast Attachment
Authors: Borcherding Kai , Marx Dennis , Gätjen Linda , Specht Uwe , Salz Dirk , Thiel Karsten , Wildemann Britt , Grunwald Ingo
Published: April 2020

Improved implant osteointegration offers meaningful potential for orthopedic, spinal, and dental implants. In this study, a laser treatment was used for the structuring of a titanium alloy (Ti6Al4V) surface combined with a titanium dioxide coating, whereby a porous surface was created. The objective was to characterize the pore structure shape, treatment-related metallographic changes, cytocompatibility, and attachment of osteoblast-like cells (MG-63). The treatment generated specific bottleneck pore shapes, offering the potential for the interlocking of osteoblasts within undercuts in the implant surface. The pore dimensions were a bottleneck diameter of 27 µm (SD: 4 µm), an inner pore width of 78 µm (SD: 6 µm), and a pore depth of 129 µm (SD: 8 µm). The introduced energy of the laser changed the metallic structure of the alloy within the heat-affected region (approximately 66 µm) without any indication of a micro cracking formation. The phase of the alloy (microcrystalline alpha + beta) was changed to a martensite alpha phase in the surface region and an alpha + beta phase in the transition region between the pores. The MG-63 cells adhered to the structured titanium surface within 30 min and grew with numerous filopodia over and into the pores over the following days. Cell viability was improved on the structured surface compared to pure titanium, indicating good cytocompatibility. In particular, the demonstrated affinity of MG-63 cells to grow into the pores offers the potential to provide significantly improved implant fixation in further in vivo studies.
Mechanical and Damping Properties of Recycled Aggregate Concrete Modified with Air-Entraining Agent and Polypropylene Fiber
Authors: Zhou Chonggang , Pei Xingwang , Li Wenlong , Liu Yijun
Published: April 2020

In this study, recycled aggregate concrete (RAC) modified with polypropylene fiber (PP) and air-entraining agent (AGA) was prepared, and the effects of PP and AGA on the static (compressive strength, Young’s modulus, and splitting tensile strength) and dynamic properties (dynamic modulus of elasticity and damping ratio) of RAC were investigated. The experimental results showed that the addition of an AGA and PP had a favorable effect on the damping ratio of the concrete, however, the addition of the AGA had a slightly negative effect on the mechanical performance of the concrete. The AGA and PP contents required to achieve the optimum damping ratio of the concrete with the least reduction in the mechanical performance were 0.02% and 0.10%, respectively. Furthermore, the addition of AGA was more effective than that of PP in improving the damping property of the concrete.
Putative Inhibitors of SARS-CoV-2 Main Protease from A Library of Marine Natural Products: A Virtual Screening and Molecular Modeling Study
Authors: Gentile Davide , Patamia Vincenzo , Scala Angela , Sciortino Maria Teresa , Piperno Anna , Rescifina Antonio
Published: April 2020

The current emergency due to the worldwide spread of the COVID-19 caused by the new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a great concern for global public health. Already in the past, the outbreak of severe acute respiratory syndrome (SARS) in 2003 and Middle Eastern respiratory syndrome (MERS) in 2012 demonstrates the potential of coronaviruses to cross-species borders and further underlines the importance of identifying new-targeted drugs. An ideal antiviral agent should target essential proteins involved in the lifecycle of SARS-CoV. Currently, some HIV protease inhibitors (i.e., Lopinavir) are proposed for the treatment of COVID-19, although their effectiveness has not yet been assessed. The main protease (Mpro) provides a highly validated pharmacological target for the discovery and design of inhibitors. We identified potent Mpro inhibitors employing computational techniques that entail the screening of a Marine Natural Product (MNP) library. MNP library was screened by a hyphenated pharmacophore model, and molecular docking approaches. Molecular dynamics and re-docking further confirmed the results obtained by structure-based techniques and allowed this study to highlight some crucial aspects. Seventeen potential SARS-CoV-2 Mpro inhibitors have been identified among the natural substances of marine origin. As these compounds were extensively validated by a consensus approach and by molecular dynamics, the likelihood that at least one of these compounds could be bioactive is excellent.
New Approaches for Cryptococcosis Treatment
Authors: Spadari Cristina de Castro , Wirth Fernanda , Lopes Luciana Biagini , Ishida Kelly
Published: April 2020

Cryptococcosis is an important opportunistic infection and a leading cause of meningitis in patients with HIV infection. The antifungal pharmacological treatment is limited to amphotericin B, fluconazole and 5- flucytosine. In addition to the limited pharmacological options, the high toxicity, increased resistance rate and difficulty of the currently available antifungal molecules to cross the blood–brain barrier hamper the treatment. Thus, the search for new alternatives for the treatment of cryptococcal meningitis is extremely necessary. In this review, we describe the therapeutic strategies currently available, discuss new molecules with antifungal potential in different phases of clinical trials and in advanced pre-clinical phase, and examine drug nanocarriers to improve delivery to the central nervous system.
Facile Synthesis of Solution-Processed Silica and Polyvinyl Phenol Hybrid Dielectric for Flexible Organic Transistors
Authors: Chen Xiong , Zhang Yu , Guan Xiangfeng , Zhang Hao
Published: April 2020

A high-quality dielectric layer is essential for organic thin-film transistors (OTFTs) operated at a low-power consumption level. In this study, a facile improved technique for the synthesis of solution-processed silica is proposed. By optimizing the synthesis and processing technique fewer pores were found on the surface of the film, particularly no large holes were observable after improving the annealing process, and the improved solution–gelation (sol–gel) SiOx dielectric achieved a higher breakdown strength (1.6 MV/cm) and lower leakage current density (10−8 A/cm2 at 1.5 MV/cm). Consequently, a pentacene based OTFT with a high field effect mobility (~1.8 cm2/Vs), a low threshold voltage (−1.7 V), a steeper subthreshold slope (~0.4 V/dec) and a relatively high on/off ratio (~105) was fabricated by applying a hybrid gate insulator which consisted of improved sol–gel SiOx and polyvinyl phenol (PVP). This could be ascribed to both the high k of SiOx and the smoother, hydrophobic dielectric surface with low trap density, which was proved by atomic force microscopy (AFM) and a water contact angle test, respectively. Additionally, we systematically studied and evaluated the stability of devices in the compressed state. The devices based on dielectric fabricated by conventional sol–gel processes were more susceptible to the curvature. While the improved device presented an excellent mechanic strength, it could still function at the higher bending compression without a significant degradation in performance. Thus, this solution-process technology provides an effective approach to fabricate high-quality dielectric and offers great potential for low-cost, fast and portable organic electronic applications.
Synergy Effect of Au and SiO2 Modification on SnO2 Sensor Properties in VOCs Detection in Humid Air
Authors: Gulevich Dayana , Rumyantseva Marina , Gerasimov Evgeny , Khmelevsky Nikolay , Tsvetkova Elena , Gaskov Alexander
Published: April 2020

Nanocomposites based on Au- and SiO2-modified SnO2 were studied as sensitive materials for ethanol and benzene detection in dry (RH = 1%) and humid (RH = 20%) air. Modification of SnO2 by amorphous SiO2 (13 mol.%) was effectuated by hydrothermal synthesis; modification by Au nanoparticles (1 wt.%) was carried out via impregnation by citrate-stabilized Au sol. The composition of the samples was determined by X-ray fluorescent spectroscopy and energy-dispersive X-ray spectroscopy. The microstructure was characterized by XRD, HRTEM, and low-temperature nitrogen adsorption. The surface groups were investigated by XPS, TPR-H2, and FTIR spectroscopy. DRIFT spectroscopy was performed to investigate the interaction between ethanol and the surface of the synthesized materials. Studies of the sensor properties have shown that in all cases the most sensitive is the SnO2/SiO2-Au nanocomposite. This material retains high sensitivity even in a humid atmosphere. The obtained results are discussed in terms of the synergistic effect of two modifiers (Au and SiO2) in the formation of sensor properties of SnO2/SiO2–Au nanocomposites.
Preparation and Characterization of Polypropylene/Carbon Nanotubes (PP/CNTs) Nanocomposites as Potential Strain Gauges for Structural Health Monitoring
Authors: Coppola Bartolomeo , Di Maio Luciano , Incarnato Loredana , Tulliani Jean-Marc
Published: April 2020

Polypropylene/carbon nanotubes (PP/CNTs) nanocomposites with different CNTs concentrations (i.e., 1, 2, 3, 5 and 7 wt%) were prepared and tested as strain gauges for structures monitoring. Such sensors were embedded in cementitious mortar prisms and tested in 3-point bending mode recording impedance variation at increasing load. First, thermal (differential scanning calorimetry (DSC), thermo-gravimetric analysis (TGA)), mechanical (tensile tests) and morphological (FE-SEM) properties of nanocomposites blends were assessed. Then, strain-sensing tests were carried out on PP/CNTs strips embedded in cementitious mortars. PP/CNTs nanocomposites blends with CNTs content of 1, 2 and 3 wt% did not show significant results because these concentrations are below the electrical percolation threshold (EPT). On the contrary, PP/CNTs nanocomposites with 5 and 7 wt% of CNTs showed interesting sensing properties. In particular, the best result was highlighted for the PP/CNT nanocomposite with 5 wt% CNTs for which an average gauge factor (GF) of approx. 1400 was measured. Moreover, load-unload cycles reported a good recovery of the initial impedance. Finally, a comparison with some literature results, in terms of GF, was done demonstrating the benefits deriving from the use of PP/CNTs strips as strain-gauges instead of using conductive fillers in the bulk matrix.
Bus Stops Near Schools Advertising Junk Food and Sugary Drinks
Authors: Huang Donna , Brien Amanda , Omari Lima , Culpin Angela , Smith Melody , Egli Victoria
Published: April 2020

Children rarely understand the full extent of the persuasive purpose of advertising on their eating behaviours. Addressing the obesogenic environments in which children live, through a quantification of outdoor advertising, is essential in informing policy changes and enforcing stricter regulations. This research explores the proportion of bus stop advertisements promoting non-core food and beverages within walking distance (500 m) from schools in Auckland, New Zealand while using Google Street View. Information was collected on: school type, decile, address, Walk Score®, and Transit Score for all 573 schools in the Auckland region. Ground-truthing was conducted on 10% of schools and showed an alignment of 87.8%. The majority of advertisements on bus shelters were for non-food items or services (n = 541, 64.3%). Of the advertisements that were for food and/or beverages, the majority were for non-core foods (n = 108, 50.2%). There was no statistically significant difference between the variables core and non-core food and beverages and School decile (tertiles), Walk Score (quintiles), and Transit Score (quintiles). 12.8% of all bus stop advertisements in this study promoted non-core dietary options; highlighting an opportunity for implementing stricter regulations and policies preventing advertising unhealthy food and drink to children in New Zealand.