bluuebunny/crossref_metadata_2025 huggingface dataset:
Persistence of spin memory in a crystalline, insulating phase-change material
Authors: Reindl Johannes , Volker Hanno , Breznay Nicholas P. , Wuttig Matthias
Published: December 2019

The description of disorder-induced electron localization by Anderson over 60 years ago began a quest for novel phenomena emerging from electronic interactions in the presence of disorder. Even today, the interplay of interactions and disorder remains incompletely understood. This holds in particular for strongly disordered materials where charge transport depends on ‘hopping’ between localized sites. Here we report an unexpected spin sensitivity of the electrical conductivity at the transition from diffusive to hopping conduction in a material that combines strong spin-orbit coupling and weak inter-electronic interactions. In thin films of the disordered crystalline phase change material SnSb2Te4, a distinct change in electrical conductance with applied magnetic field is observed at low temperatures. This magnetoconductance changes sign and becomes anisotropic at the disorder-driven crossover from strongly localized (hopping) to weakly localized (diffusive) electron motion. The positive and isotropic magnetoconductance arises from disruption of spin correlations that inhibit hopping transport. This experimental observation of a recently hypothesized ‘spin memory’ demonstrates the spin plays a previously overlooked role in the disorder-driven transition between weak and strong localization in materials with strong spin–orbit interactions.
Genetic and epigenetic alterations induced by bisphenol A exposure during different periods of spermatogenesis: from spermatozoa to the progeny
Authors: Lombó Marta , Fernández-Díez Cristina , González-Rojo Silvia , Herráez María Paz
Published: December 2019

Exposure to bisphenol A (BPA) has been related to male reproductive disorders. Since this endocrine disruptor also displays genotoxic and epigenotoxic effects, it likely alters the spermatogenesis, a process in which both hormones and chromatin remodeling play crucial roles. The hypothesis of this work is that BPA impairs early embryo development by modifying the spermatic genetic and epigenetic information. Zebrafish males were exposed to 100 and 2000 μg/L BPA during early spermatogenesis and during the whole process. Genotoxic and epigenotoxic effects on spermatozoa (comet assay and immunocytochemistry) as well as progeny development (mortality, DNA repairing activity, apoptosis and epigenetic profile) were evaluated. Exposure to 100 µg/L BPA during mitosis slightly increased sperm chromatin fragmentation, enhancing DNA repairing activity in embryos. The rest of treatments promoted high levels of sperm DNA damage, triggering apoptosis in early embryo and severely impairing survival. Regarding epigenetics, histone acetylation (H3K9Ac and H3K27Ac) was similarly enhanced in spermatozoa and embryos from males exposed to all the treatments. Therefore, BPA male exposure jeopardizes embryonic survival and development due to the transmission of a paternal damaged genome and of a hyper-acetylated histone profile, both alterations depending on the dose of the toxicant and the temporal window of exposure.
Independently tunable electromagnetically induced transparency effect and dispersion in a multi-band terahertz metamaterial
Authors: Sarkar Rakesh , Ghindani Dipa , Devi Koijam Monika , Prabhu S. S. , Ahmad Amir , Kumar Gagan
Published: December 2019

In this article, we experimentally and numerically investigate a planar terahertz metamaterial (MM) geometry capable of exhibiting independently tunable multi-band electromagnetically induced transparency effect (EIT). The MM structure exhibits multi-band EIT effect due to the strong near field coupling between the bright mode of the cut-wire (CW) and dark modes of pair of asymmetric double C resonators (DCRs). The configuration allows us to independently tune the transparency windows which is challenging task in multiband EIT effect. The independent modulation is achieved by displacing one DCR with respect to the CW, while keeping the other asymmetric DCR fixed. We further examine steep dispersive behavior of the transmission spectra within the transparency windows and analyze slow light properties. A coupled harmonic oscillator based theoretical model is employed to elucidate as well as understand the experimental and numerical observations. The study can be highly significant in the development of multi-band slow light devices, buffers and modulators.
The selective GSK3 inhibitor, SAR502250, displays neuroprotective activity and attenuates behavioral impairments in models of neuropsychiatric symptoms of Alzheimer’s disease in rodents
Authors: Griebel Guy , Stemmelin Jeanne , Lopez-Grancha Mati , Boulay Denis , Boquet Gerald , Slowinski Franck , Pichat Philippe , Beeské Sandra , Tanaka Shinji , Mori Akiko , Fujimura Masatake , Eguchi Junichi
Published: December 2019

Glycogen synthase kinase 3 (GSK3) has been identified as a promising target for the treatment of Alzheimer’s disease (AD), where abnormal activation of this enzyme has been associated with hyperphosphorylation of tau proteins. This study describes the effects of the selective GSK3 inhibitor, SAR502250, in models of neuroprotection and neuropsychiatric symptoms (NPS) associated with AD. In P301L human tau transgenic mice, SAR502250 attenuated tau hyperphosphorylation in the cortex and spinal cord. SAR502250 prevented the increase in neuronal cell death in rat embryonic hippocampal neurons following application of the neurotoxic peptide, Aβ25–35. In behavioral studies, SAR502250 improved the cognitive deficit in aged transgenic APP(SW)/Tau(VLW) mice or in adult mice after infusion of Aβ25–35. It attenuated aggression in the mouse defense test battery and improved depressive-like state of mice in the chronic mild stress procedure after 4 weeks of treatment. Moreover, SAR502250 decreased hyperactivity produced by psychostimulants. In contrast, the drug failed to modify anxiety-related behaviors or sensorimotor gating deficit. This profile confirms the neuroprotective effects of GSK3 inhibitors and suggests an additional potential in the treatment of some NPS associated with AD.
Thermally Triggered Vanishing Bulk Polyoxymethylene for Transient Electronics
Authors: Liu Dongqing , Zhang Songhe , Cheng Haifeng , Peng Renfu , Luo Zhijian
Published: December 2019

Transient materials capable of disappearing rapidly and completely are critical for transient electronics. End-capped polyoxymethylene (POM) has excellent mechanical properties and thermal stability. However, research concerning the inherent thermal instability of POM without end-capping to obtain transient rather than stable materials, has never been reported. Here, POM without end-capping is proposed as a novel thermally triggered transient solid material that can vanish rapidly by undergoing conversion to a volatile gas, and a chemical vapor deposition method is developed to obtain a smooth POM substrate from the synthesized POM powder. Experimental and theoretical analysis was employed to reveal the mechanism whereby the POM substrate formed and vanished. A Cr/Au/SiO2/Cu memristor device, which was successfully deposited on the POM substrate by physical vapor deposition, exhibits bipolar resistive switching, suggesting that the POM substrate is suitable for use in electrical devices. Thermal triggering causes the POM substrate to vanish as the memristor disintegrates, confirming excellent transient performance. The deposited bulk POM material can completely vanish by thermally triggered depolymerization, and is suitable for physically transient substrates and packaging materials, demonstrating great prospects for application in transient electronics for information security.
Methyl jasmonate promote protostane triterpenes accumulation by up-regulating the expression of squalene epoxidases in Alisma orientale
Authors: Tian Rong , Gu Wei , Gu Yuchen , Geng Chao , Xu Fei , Wu Qinan , Chao Jianguo , Xue Wenda , Zhou Chen , Wang Fan
Published: December 2019

Protostane triterpenes, which are found in Alisma orientale, are tetracyclic triterpenes with distinctive pharmacological activities. The natural distribution of protostane triterpenes is limited mainly to members of the botanical family Alismataceae. Squalene epoxidase (SE) is the key rate-limiting enzyme in triterpene biosynthesis. In this study, we report the characterization of two SEs from A. orientale. AoSE1 and AoSE2 were expressed as fusion proteins in E. coli, and the purified proteins were used in functional research. In vitro enzyme assays showed that AoSE1 and AoSE2 catalyze the formation of oxidosqualene from squalene. Immunoassays revealed that the tubers contain the highest levels of AoSE1 and AoSE2. After MeJA induction, which is the main elicitor of triterpene biosynthesis, the contents of 2,3-oxidosqualene and alisol B 23-acetate increased by 1.96- and 2.53-fold, respectively. In addition, the expression of both AoSE proteins was significantly increased at four days after MeJA treatment. The contents of 2,3-oxidosqualene and alisol B 23-acetate were also positively correlated with AoSEs expression at different times after MeJA treatment. These results suggest that AoSE1 and AoSE2 are the key regulatory points in protostane triterpenes biosynthesis, and that MeJA regulates the biosynthesis of these compounds by increasing the expression of AoSE1 and AoSE2.
Telomerase increasing compound protects hippocampal neurons from amyloid beta toxicity by enhancing the expression of neurotrophins and plasticity related genes
Authors: Baruch-Eliyahu Natalie , Rud Vladislav , Braiman Alex , Priel Esther
Published: December 2019

The telomerase reverse transcriptase protein, TERT, is expressed in the adult brain and its exogenic expression protects neurons from oxidative stress and from the cytotoxicity of amyloid beta (Aβ). We previously showed that telomerase increasing compounds (AGS) protected neurons from oxidative stress. Therefore, we suggest that increasing TERT by AGS may protect neurons from the Aβ-induced neurotoxicity by influencing genes and factors that participate in neuronal survival and plasticity. Here we used a primary hippocampal cell culture exposed to aggregated Aβ and hippocampi from adult mice. AGS treatment transiently increased TERT gene expression in hippocampal primary cell cultures in the presence or absence of Aβ and protected neurons from Aβ induced neuronal degradation. An increase in the expression of Growth associated protein 43 (GAP43), and Feminizing locus on X-3 genes (NeuN), in the presence or absence of Aβ, and Synaptophysin (SYP) in the presence of Aβ was observed. GAP43, NeuN, SYP, Neurotrophic factors (NGF, BDNF), beta-catenin and cyclin-D1 expression were increased in the hippocampus of AGS treated mice. This data suggests that increasing TERT by pharmaceutical compounds partially exerts its neuroprotective effect by enhancing the expression of neurotrophic factors and neuronal plasticity genes in a mechanism that involved Wnt/beta-catenin pathway.
Non-proliferative neurogenesis in human periodontal ligament stem cells
Authors: Bueno Carlos , Martínez-Morga Marta , Martínez Salvador
Published: December 2019

Understanding the sequence of events from undifferentiated stem cells to neuron is not only important for the basic knowledge of stem cell biology, but also for therapeutic applications. In this study we examined the sequence of biological events during neural differentiation of human periodontal ligament stem cells (hPDLSCs). Here, we show that hPDLSCs-derived neural-like cells display a sequence of morphologic development highly similar to those reported before in primary neuronal cultures derived from rodent brains. We observed that cell proliferation is not present through neurogenesis from hPDLSCs. Futhermore, we may have discovered micronuclei movement and transient cell nuclei lobulation coincident to in vitro neurogenesis. Morphological analysis also reveals that neurogenic niches in the adult mouse brain contain cells with nuclear shapes highly similar to those observed during in vitro neurogenesis from hPDLSCs. Our results provide additional evidence that it is possible to differentiate hPDLSCs to neuron-like cells and suggest the possibility that the sequence of events from stem cell to neuron does not necessarily requires cell division from stem cell.
Improved RNA modification mapping of cellular non-coding RNAs using C- and U-specific RNases
Authors: Thakur Priti , Estevez Mariana , Lobue Peter A. , Limbach Patrick A. , Addepalli Balasubrahmanyam
Published: December 2019

Improved RNA modification mapping through complementary nucleobase-specific ribonucleases.
On-chip electromembrane extraction followed by sensitive digital image-based colorimetry for determination of trace amounts of Cr(vi)
Authors: Zarghampour Fereshteh , Yamini Yadollah , Baharfar Mahroo , Javadian Ghazal , Faraji Mohammad
Published: December 2019

In this work, an on-chip electromembrane extraction coupled with the micro solid phase extraction step was developed for extraction, preconcentration, and determination of trace amounts of chromium(vi) in water samples.
Ligand-conjugated quantum dots for fast sub-diffraction protein tracking in acute brain slices
Authors: Thal Lucas B. , Mann Victor R. , Sprinzen David , McBride James R. , Reid Kemar R. , Tomlinson Ian D. , McMahon Douglas G. , Cohen Bruce E. , Rosenthal Sandra J.
Published: December 2019

We introduce a quantum dot probe for high-spatiotemporal imaging in brain tissue and reassess the utility of commercially available probes.
Formation of allylated quaternary carbon centersviaC–O/C–O bond fragmentation of oxalates and allyl carbonates
Authors: Chen Haifeng , Ye Yang , Tong Weiqi , Fang Jianhui , Gong Hegui
Published: December 2019

Fe-Promoted reductive coupling of tertiary alkyl oxalates with allylic carbonates enables the formation of all C(sp3)–quaternary carbon centersviaa double C–O bond fragmentation process.
Switching to a “turn-on” fluorescent probe for selective monitoring of cyanide in food samples and living systems
Authors: Wu Hai , Chen Miaomiao , Xu Qinqin , Zhang Ying , Liu Pingping , Li Wenyong , Fan Suhua
Published: December 2019

A “turn-on” fluorescent probe was designed by changing the structure of a “turn-off” probe for monitoring cyanide in food samples and living systems.
Modulation of enzymatic activity by aqueous two-phase systems and pressure – rivalry between kinetic constants
Authors: Oliva Rosario , Banerjee Sudeshna , Cinar Hasan , Winter Roland
Published: December 2019

Both, pressure and aqueous two-phase systems are able to modulate the kinetic parameters of enzymatic reactions.
In situ synthesis of crystalline Ag–WO3 nanosheets with enhanced solar photo-electrochemical performance for splitting water
Authors: Wen Puhong , Wang Chuanchuan , Lan Yuzhu , Jiang Xiaowen , Ren Lijun
Published: December 2019

The evolution mechanisms of morphology and crystal structure were studied in the synthesis process of WO3 nanosheets preferentially exposing the (100) facet. And their photocatalytic performance after doping Ag was evaluated by splitting water.
Cu-Deficient plasmonic Cu2−xS nanocrystals induced tunable photocatalytic activities
Authors: Shao Xiao , Zhang Tianyong , Li Bin , Wu Yue , Ma Xiaoyuan , Wang Jingchao , Jiang Shuang
Published: December 2019

Cu-Deficient plasmonic Cu2−xS nanocrystals with tunable photocatalytic activities were synthesized and investigated.
Aromatic ouroboroi: heterocycles involving a σ-donor–acceptor bond and 4n + 2 π-electrons
Authors: Báez-Grez Rodrigo , Inostroza Diego , García Victor , Vásquez-Espinal Alejandro , Donald Kelling J. , Tiznado William
Published: December 2019

The aromaticity and dynamics of a set of recently proposed neutral 5- and 6-membered heterocycles that are closed by dative (donor–acceptor) or multi-center σ bonds, and have resonance forms with a Hückel number of π-electrons, are examined.
Predicting the α-relaxation time of glycerol confined in 1.16 nm pores of zeolitic imidazolate frameworks
Authors: Ngai K. L. , Lunkenheimer P. , Loidl A.
Published: December 2019

Relaxation times of glycerol confined in 1.16 nm ZIF pores found by Uhl et al. [J. Chem. Phys., 2019, 150, 024504] are explained quantitatively by the Coupling Model.
Three-dimensional line edge roughness in pre- and post-dry etch line and space patterns of block copolymer lithography
Authors: Pinge Shubham , Qiu Yufeng , Monreal Victor , Baskaran Durairaj , Ravirajan Abhaiguru , Joo Yong Lak
Published: December 2019

In this work, we employ large-scale coarse-grained molecular dynamics (CGMD) simulations to study the three-dimensional line edge roughness associated with line and space patterns of chemo-epitaxially directed symmetric block copolymers.
Defining aluminum-zoning during synthesis of ZSM-5 zeolites
Authors: Li Teng , Krumeich Frank , Chen Ming , Ma Zhiqiang , van Bokhoven Jeroen A.
Published: December 2019

The aluminum migration toward the surface and the delayed addition of high-aluminum-containing species contribute to the aluminum-zoning of ZSM-5 zeolites.
The reduction potential of the slipped GC base pair in one-electron oxidized duplex DNA
Authors: Anderson Robert F. , Shinde Sujata S. , Maroz Andrej , Reynisson Jóhannes
Published: December 2019

The kinetics and energetics for the perturbation of the GC base pair radical to a more stable ‘slipped structure are determined.
Microalgae aqueous extracts exert intestinal protective effects in Caco-2 cells and dextran sodium sulphate-induced mouse colitis
Authors: Guo Wei , Zhu Suqin , Feng Guangxin , Wu Lingyu , Feng Yinong , Guo Tengjiao , Yang Yisheng , Wu Haohao , Zeng Mingyong
Published: December 2019

Aqueous extracts fromChlorella pyrenoidosa,Spirulina platensisandSynechococcussp. PCC 7002 showed gut protective potentialin vitroandin vivo.
Restoration of myocellular copper-trafficking proteins and mitochondrial copper enzymes repairs cardiac function in rats with diabetes-evoked heart failure
Authors: Zhang Shaoping , Liu Hong , Amarsingh Greeshma Vazhoor , Cheung Carlos C H , Wu Donghai , Narayanan Umayal , Zhang Linda , Cooper Garth J S
Published: December 2019

Diabetes impairs systemic copper regulation, and acts as a major independent risk factor for heart failure (HF) wherein mitochondrial dysfunction is a key pathogenic process. Here we asked whether diabetes might alter mitochondrial structure/function and thus impair cardiac performance by damaging myocellular pathways that mediate cell-copper homeostasis. We measured activity of major mitochondria-resident copper-enzymes cytochrome c oxidase (mt-Cco) and superoxide dismutase 1 (mt-Sod1); expression of three main mitochondrial copper-chaperones [Cco copper chaperone 17 (Cox17), Cox11, and mitochondria-resident copper chaperone for Sod1 (mt-Ccs)]; of copper-dependent Cco-assembly protein Sco1; and regulation of mitochondrial biogenesis, in left-ventricular (LV) tissue from groups of non-diabetic-control, untreated-diabetic, and divalent-copper-selective chelator-treated diabetic rats. Diabetes impaired LV pump function; ∼halved LV-copper levels; substantively decreased myocellular expression of copper chaperones, and enzymatic activity of mt-Cco and mt-Sod1. Divalent-copper chelation with triethylenetetramine improved cardiac pump function, restored levels of myocardial copper, the copper chaperones, and Sco1; and enzymatic activity of mt-Cco and mt-Sod1. Copper chelation also restored expression of the key mitochondrial biogenesis regulator, peroxisome-proliferator-activated receptor gamma co-activator-1α (Pgc-1α). This study shows for the first time that altered myocardial copper-trafficking is a key pathogenic process in diabetes-evoked HF. We also describe a novel therapeutic effect of divalent-copper-selective chelation, namely restoration of myocellular copper trafficking, which is thus revealed as a potentially tractable target for novel pharmacological intervention to improve cardiac function.
Strong pyrrolic-N–Pd interactions boost the electrocatalytic hydrodechlorination reaction on palladium nanoparticles
Authors: Wang Peng , Shi Xuelin , Fu Chunhong , Li Xiangjun , Li Junxi , Lv Xiaoshu , Chu Yinghao , Dong Fan , Jiang Guangming
Published: December 2019

We demonstrated that heteroatomic nitrogen (N) doping of graphene can significantly enhance the performance of the graphene–palladium nanoparticle composite catalyst (N/G-Pd) in the electrocatalytic hydrodechlorination (EHDC) reaction.
The reticent tautomer: exploiting the interesting multisite and multitype reactivity of 4-pyrrolin-2-ones
Authors: Montagnon Tamsyn , Kalaitzakis Dimitris , Sofiadis Manolis , Vassilikogiannakis Georgios
Published: December 2019

Multisite and multitype reactivities of the highly versatile and valuable synthetic building block 4-pyrrolin-2-one are covered in this review.
The surface passivation of Ge(100) and Ge(111) anodes in Ge–air batteries with different doping types and concentrations
Authors: Yu Yingjian , Chen Danshuo , Gao Shaoshuai , Huang Jian , Hu Sujuan , Yang Hai , Jin Guojun
Published: December 2019

The atomic configurations and calculated I–V curves of different Ge/GeO2 interfaces.
Synthesis of bifunctional BaFe1−xCoxO3−y−δ(OH)y catalysts for the oxygen reduction reaction and oxygen evolution reaction
Authors: Waidha Aamir Iqbal , Ni Lingmei , Ali Jasim , Lepple Maren , Donzelli Manuel , Dasgupta Supratik , Wollstadt Stephan , Alff Lambert , Kramm U. I. , Clemens Oliver
Published: December 2019

Perovskite oxides with mixed ionic and electronic conductivities are very promising candidates for their application as energy materials related to fuel cell and metal air battery integration.
Bottom-top channeling Li nucleation and growth by a gradient lithiophilic 3D conductive host for highly stable Li-metal anodes
Authors: Yan Xiaolin , Zhang Qingfei , Xu Wanjie , Xie Qingshui , Liu Pengfei , Chen Qiulin , Zheng Hongfei , Wang Laisen , Zhu Zi-Zhong , Peng Dong-Liang
Published: December 2019

3D gradient Si-modified carbon papers (GSCP) with good electronic conductivity and gradient lithiophilic configurations can regulate Li nucleation/growth in a bottom-up manner and endow outstanding coulombic efficiency and cyclability in full cells.
A highly active and Cr-resistant infiltrated cathode for practical solid oxide fuel cells
Authors: Yang Tianrang , Wen Yeting , Wu Tao , Xu Nansheng , Huang Kevin
Published: December 2019

An SCT conformally coated LSCF–GDC cathode shows significantly improved ORR activity with a strong Cr-tolerance.
An efficient polysulfide trapper of an nitrogen and nickel-decorating amylum scaffold-coated separator for ultrahigh performance in lithium–sulfur batteries
Authors: Zuo Yinze , Zhao Meng , Ren Peijia , Su Weiming , Zhou Jian , Chen Yanbin , Tang Yuefeng , Chen Yanfeng
Published: December 2019

The powerful chemical affinity and catalysis of the N, Ni-decorating amylum for LiPSs realize a cell with high performance.
Biochemists' bliss: harnessing the power of snake toxins to treat cardiovascular diseases
Authors: Koh Cho Yeow , Kini R. Manjunatha
Published: December 2019

Deadly snake venom can be turned into life-saving therapeutics. Currently, several medicinal agents approved by the US Food and Drug Administration originated from snake venom. These include captopril, used to treat high blood pressure, as well as eptifibatide and tirofiban, used as bloodthinning agents to prevent thrombosis (clotting of blood in the circulation). Many other snake venom toxins have also been made into reagents that help to diagnose different kinds of blood disorders. Here, we discuss the molecular basis of how snake venom affects components in blood to unveil secrets behind the deadly weapon that can be harnessed for its power of healing.
Photoelectric detection of crop fungi resistance based on microfluidic
Authors: Xu Peifeng , Wu Gangshan , Xu Chao , Wang Pan , Yang Ning , Zhang Rongbiao
Published: December 2019

In view of the defects such as long time‐consuming and large limitation in the detection of pesticide resistance of crop pathogens at present. A novel photoelectric detection method based on enriched microfluidic chips is proposed for the detection of pesticide resistance of crop fungal disease. First, according to the aerodynamics characteristics of microbial aerosol particles and optical detection technology, a special enrichment microfluidic chip was designed to achieve high efficiency enrichment and high precision concentration detection of fungal spores. On this basis, based on the theory of pesticide resistance sensitivity baseline, the relationship among spore germination, systematic enrichment concentration, and optical detection concentration of Botrytis cinerea in strawberry treated with Pyrimethanil was studied, and the pesticide resistance detection model of uncultured pathogens was established. The light intensity of light source was 1.1 × 103 cd, and the wavelength was 620 nm as the optimum parameters for optical detection. The correlation coefficient between the microscopic examination of spores’ concentration and the results of optical detection is 0.9792. It has good linearity and reliability, which provides a theoretical basis for the research and development of portable equipment for detecting pesticide resistance of crop diseases.
The dry and carbon-poor inner disk of TW Hydrae: evidence for a massive icy dust trap
Authors: Bosman Arthur D. , Banzatti Andrea
Published: December 2019

Context. Gas giants accrete their envelopes from the gas and dust of proto-planetary disks, and therefore it is important to determine the composition of the inner few astronomical units, where most giant planets are expected to form.

Aims. We aim to constrain the elemental carbon and oxygen abundance in the inner disk (R <  2.3 AU) of TW Hya and compare with the outer disk (R >  2.3 AU) where carbon and oxygen appear underabundant by a factor of approximately 50.

Methods. Archival Spitzer-IRS and VLT-CRIRES observations of TW Hya were compared with a detailed thermo-chemical model, DALI. The inner disk gas mass and elemental C and O abundances were varied to fit the mid-infrared H2 and H2O line fluxes as well as the near-infrared CO line flux.

Results. Best-fitting models have an inner disk that has a gas mass of 2 × 10−4 M⊙ with C/H ≈ 3 × 10−6 and O/H ≈ 6 × 10−6. The elemental oxygen and carbon abundances of the inner disk are about 50 times lower than in the interstellar medium and are consistent with those found in the outer disk.

Conclusions. The uniformly low volatile abundances imply that the inner disk is not enriched by ices on drifting bodies that evaporate. This indicates that drifting grains are stopped in a dust trap outside the water ice line. Such a dust trap would also form a cavity as seen in high-resolution submillimeter continuum observations. If CO is the major carbon carrier in the ices, dust needs to be trapped efficiently outside the CO ice line of ∼20 AU. This would imply that the shallow submillimeter rings in the TW Hya disk outside of 20 AU correspond to very efficient dust traps. The most likely scenario is that more than 98% of the CO has been converted into less volatile species, for example CO2 and CH3OH. A giant planet forming in the inner disk would be accreting gas with low carbon and oxygen abundances as well as very little icy dust, potentially leading to a planet atmosphere with strongly substellar C/H and O/H ratios.
The flickering nuclear activity of Fornax A
Authors: Maccagni F. M. , Murgia M. , Serra P. , Govoni F. , Morokuma-Matsui K. , Kleiner D. , Buchner S. , Józsa G. I. G. , Kamphuis P. , Makhathini S. , Molnár D. Cs. , Prokhorov D. A. , Ramaila A. , Ramatsoku M. , Thorat K. , Smirnov O.
Published: December 2019

We present new observations of Fornax A taken at ∼1 GHz with the MeerKAT telescope and at ∼6 GHz with the Sardinia Radio Telescope (SRT). The sensitive (noise ∼16 μJy beam−1), high-resolution (≲10″) MeerKAT images show that the lobes of Fornax A have a double-shell morphology, where dense filaments are embedded in a diffuse and extended cocoon. We study the spectral properties of these components by combining the MeerKAT and SRT observations with archival data between 84 MHz and 217 GHz. For the first time, we show that multiple episodes of nuclear activity must have formed the extended radio lobes. The modelling of the radio spectrum suggests that the last episode of injection of relativistic particles into the lobes started ∼24 Myr ago and stopped 12 Myr ago. More recently (∼3 Myr ago), a less powerful and short (≲1 Myr) phase of nuclear activity generated the central jets. Currently, the core may be in a new active phase. It appears that Fornax A is rapidly flickering. The dense environment around Fornax A has lead to a complex recent merger history for this galaxy, including mergers spanning a range of gas contents and mass ratios, as shown by the analysis of the galaxy’s stellar- and cold-gas phases. This complex recent history may be the cause of the rapid, recurrent nuclear activity of Fornax A.
Demographics of disks around young very low-mass stars and brown dwarfs in Lupus
Authors: Sanchis E. , Testi L. , Natta A. , Manara C. F. , Ercolano B. , Preibisch T. , Henning T. , Facchini S. , Miotello A. , de Gregorio-Monsalvo I. , Lopez C. , Mužić K. , Pascucci I. , Santamaría-Miranda A. , Scholz A. , Tazzari M. , van Terwisga S. , Williams J. P.
Published: December 2019

We present new 890 μm continuum ALMA observations of five brown dwarfs (BDs) with infrared excess in Lupus I and III, which in combination with four previously observed BDs allowed us to study the millimeter properties of the full known BD disk population of one star-forming region. Emission is detected in five out of the nine BD disks. Dust disk mass, brightness profiles, and characteristic sizes of the BD population are inferred from continuum flux and modeling of the observations. Only one source is marginally resolved, allowing for the determination of its disk characteristic size. We conduct a demographic comparison between the properties of disks around BDs and stars in Lupus. Due to the small sample size, we cannot confirm or disprove a drop in the disk mass over stellar mass ratio for BDs, as suggested for Ophiuchus. Nevertheless, we find that all detected BD disks have an estimated dust mass between 0.2 and 3.2 M⊙; these results suggest that the measured solid masses in BD disks cannot explain the observed exoplanet population, analogous to earlier findings on disks around more massive stars. Combined with the low estimated accretion rates, and assuming that the mm-continuum emission is a reliable proxy for the total disk mass, we derive ratios of Ṁacc∕Mdisk that are significantly lower than in disks around more massive stars. If confirmed with more accurate measurements of disk gas masses, this result could imply a qualitatively different relationship between disk masses and inward gas transport in BD disks.
Disks Around T Tauri Stars with SPHERE (DARTTS-S)
Authors: Garufi A. , Avenhaus H. , Pérez S. , Quanz S. P. , van Holstein R. G. , Bertrang G. H.-M. , Casassus S. , Cieza L. , Principe D. A. , van der Plas G. , Zurlo A.
Published: December 2019

Context. Near-IR polarimetric images of protoplanetary disks enable us to characterize substructures that might be due to the interaction with (forming) planets. The available census is strongly biased toward massive disks around old stars, however.

Aims. The DARTTS program aims at alleviating this bias by imaging a large number of T Tauri stars with diverse properties.

Methods. DARTTS-S employs VLT/SPHERE to image the polarized scattered light from disks. In parallel, DARTTS-A provides ALMA images of the same targets for a comparison of different dust components. In this work, we present new SPHERE images of 21 circumstellar disks, which is the largest sample released to date. We also recalculated some relevant stellar and disk properties following Gaia DR2.

Results. The targets of this work are significantly younger than those published thus far with polarimetric near-IR (NIR) imaging. Scattered light is unambiguously resolved in 11 targets, and some polarized unresolved signal is detected in 3 additional sources. Some disk substructures are detected. However, the paucity of spirals and shadows from this sample reinforces the trend according to which these NIR features are associated with Herbig stars, either because they are older or more massive. Furthermore, disk rings that are apparent in ALMA observations of some targets do not appear to have corresponding detections with SPHERE. Inner cavities larger than ~15 au are also absent from our images, even though they are expected from the spectral energy distribution. On the other hand, 3 objects show extended filaments at larger scale that are indicative of strong interaction with the surrounding medium. All but one of the undetected disks are best explained by their limited size (≲20 au), and the high occurrence of stellar companions in these sources suggests an important role in limiting the disk size. One undetected disk is massive and very large at millimeter wavelengths, implying that it is self-shadowed in the NIR.

Conclusions. This work paves the way toward a more complete and less biased sample of scattered-light observations, which is required to interpret how disk features evolve throughout the disk lifetime.
The effects of growth TiO2 nanotubes on forged Ti6Al4V alloy and selectivelaser sintered Ti6Al4V alloy surfaces for environment and medical applications
Authors: Dincă (Shamieh) Boulven Luciana Laura , Banu Alexandra , Soylu Gizem Nur , Dobri Gabriel , Mocirla (Mihai) Madalina Elena
Published: December 2019

The paper describes the effect of growth TiO2 nanotubes on titanium surfaces by anodic oxidation forenvironmental and medical applications. The importance of the metallurgical state of TiAl6V alloy on the growing of TiO2 nanotubes by anodization will be highlighted. Starting from the possibility of obtaining the TiO2 nanotubes, the paper presents results on TiO2 nanotubes grown by electrochemical anodization method, using a solution containing HF 0,4% and having as electrodes, graphiteas cathode and titanium alloy specimens obtained by two technologies: by cold plastic deformation as well as by additive manufacturing process SLS, as anode. So, the nanotubes were produced by anodization and analysed by scanning electron microscopy. The aim of this paper is to compare the electrochemical formation of TiO2 on the surface of both specimens knowing that the titanium alloys and its oxides are used in many biomedicaland environmental applications, thus providing the importance of nanotubes and the fact that their properties open doors in these fields.
The kinematic approach to edge-chipping in rotary ultrasonic machining of Al2O3
Authors: Kuruc Marcel , Zvončan Marek , Peterka Jozef
Published: December 2019

Rotary ultrasonic machining (RUM) is useful in the machining of difficult-to-cut materials such as Al2O3. However, the edge-chipping occurs in the machined surface because of the brittleness of ceramics.The origin of edge-chipping is clear in general and several methods to its reduction have been published, briefly described in the article. The article brings new, kinematics based view on the edge-chippingorigin and a method of its reduction. Theoretical equations were deduced based on the grit´s trajectory characterized by machining variables of the processes. The equations have been employed in a full factorial experiment and experimental results fit the theoretical assumption satisfyingly. The edge–chipping was reduced by supposed method significantly.
Into the early steps of Virtual Commissioning in Tecnomatix Plant Simulation using S7-PLCSIM Advanced and STEP 7 TIA Portal
Authors: Delgado Sobrino Daynier Rolando , Ružarovský Roman , Holubek Radovan , Velíšek Karol
Published: December 2019

The commissioning of new designs, technologies, production related changes and control codes and strategies has been always a risky milestone to overcome in manufacturing. It has been carried out, in many instances, in a (quasi) poka-yoke way often leading companies to incur extra costs affecting the overall efficiency of a given project. In this regard, the emergence of novel Virtual Commissioning tools and methods have become a great asset adding to the commissioning process the values of shorter times, flexibility and reduced risks. The present paper aims at giving an introductory insight into the early steps of “Virtual Commissioning” in the software Tecnomatix Plant Simulation in conjunction with other engineering tools like the S7-PLCSIM Advanced and STEP 7 TIA Portal. It generally exploressome of the capabilities of the software, and boards the benefits of using it prior to the implementation/real commissioning. The paper further lists key steps related to the realization of this process andmakes emphasis on the interconnection and functioning of all of these tools for Virtual Commissioning purposes. At the end, there is also a simple example that implements and illustrates some of the contents and knowledge addressed.
Design of shape and dimensions of exchangeable jaws for pneumatics chuck of CNC lathe EMCO Concept TURN 105
Authors: Bučányová Marcela , Hrušková Erika , Kusá Martina
Published: December 2019

The EMCO Concept Turn 105 CNC lathe is part of the iCIM3000 production system. Currently, only a narrow range of products is processed, which is caused by the small clamping range of the 3-jaw pneumatic chuck marked KFD 85/3. Based on the requirement to expand or change the range of manufactured components, new interchangeable jaws will be designed to clamp more diameters despite a small clamping range. The design of the replaceable jaws for the pneumatic chuck is based on the determination of the shapes and dimensions of the components produced on the lathe, as well as on the shape, dimensions and characteristics of the pneumatic chuck.
Non-destructive investigation of polymer-metal bonds using a VibroMap1000 holographic vibrometer
Authors: Pawel Zawadzki , Frans Meijer , Ewa Stachowska , Stanisław Legutko
Published: December 2019

We developed a method to test polymer-metal bonds using a VibroMap1000 holographic vibrometer. The set-up and the data processing system allow non-destructive testing of polymer-metal bonds for samples of a specific size and structure. Frequency scanning from 200 Hz - 20 kHz provides characteristics of the sample. Because the method is non-destructive the sample can be studied afterwards with other methods too. These combined with the measurements of the holographic vibrometer, can create a complete and accurate assessment of the state of polymer-metal bonds. We present some preliminary results.
Optimization of the Production Process of Vibrocasted Refractory Products
Authors: Kyncl Martin , Kyncl Jiri , Slany Michal
Published: December 2019

This paper deals with the optimization of the production process of vibrocasted refractory products. The main goal is to make efficient and automate the production of moulds for refractory blocks. A theoretical research was followed by an expert analysis of the current state of the manufacturing process at an industrial partner. The next step was to analyze complete portfolio of refractory vibrocasted products, which results in choosing a representative sample whose dimensions most correspond to majority of the moulds produced. Subsequently, a design was done, to make the production process more effective with respect to time, technology and construction aspects, focusing on increasing productivity, reducing human labour and increasing production modernization. In the end, the design options were evaluated in terms of time and cost, and the ideal process of the manufacturing production was recommended with respect to the latest technology. It includes a solution for material composition and optimized design of moulds for vibrocasted refractory materials to increase production efficiency moulds and cost reduction while maintaining mould accuracy and quality. These products are subject to high demands in terms of material quality and precision, and at the same time costly to produce due to manual manufacturing.
Observations and modelling of non-proportional mixed mode cyclic loading
Authors: Vormwald Michael
Published: December 2019

Under non-proportional mixed-mode loading conditions at the crack tip, some observations are reported. They are limited to cases of cylindrical specimens under normal force and torsion. The fatigue cracks have been initiated by the same loading for which the crack growth behavior has been studied. The observations are discussed against the background of a variety of influence factors on non-proportional mixed mode growth. Finally, a couple of modeling approaches are listed which are – according to the nature or the problem – not yet developed for providing prediction tools in an engineering environment.
Multiaxial Fatigue of Additive Manufactured Metals
Authors: Fatemi Ali , Molaei Reza , Phan Nam
Published: December 2019

Additive manufacturing (AM) has recently gained much interest from researchers and industry practitioners due to the many advantages it offers as compared to the traditional subtractive manufacturing methods. These include the ability to fabricate net shaped complex geometries, integration of multiple parts, on-demand fabrication, and efficient raw material usage, among other benefits. Some of distinguishing features of AM metals, as compared to traditional subtractive manufacturing methods, include surface roughness, porosity and lack of fusion defects, residual stresses due to the thermal history of the part during the fabrication process, and anisotropy of the properties. Most components made of AM processes are subjected to cyclic loads, therefore, fatigue performance is an important consideration in their usage for safety critical applications. In addition, the state of stress at fatigue critical locations are often multiaxial. Considering the fact that many of the distinguishing features of AM metals are directional, the subject of multiaxial fatigue presents an important study area for a better understanding of their fatigue performance. This paper presents an overview of the aforementioned issues using recent data generated using AM Ti-6Al-4V and 17-4 PH stainless steel. Specimens were made by laser-based powder bed fusion and subjected to axial, torsion, and in-phase as well as out-of-phase loadings. A variety of conditions such as surface roughness, thermo-mechanical treatment, and notch effects are included. Many aspects are considered including damage mechanisms and crack paths, cyclic deformation, fatigue crack nucleation and growth, and stress concentration effects.
Approaches to fatigue life prediction under multiaxial loading
Authors: Nowell David , Sahadi Cavalheiro João Vitor
Published: December 2019

The paper will consider a set of biaxial experiments, conducted using a cruciform specimen design, manufactured from Waspaloy, a nickel superalloy used in aircraft engine disks. These are analysed using a number of standard, as well as novel, multiaxial fatigue parameters. The results show that most of the existing parameters appear to correlate the results adequately in the region which can be accessed by tension-torsion experiments, but are much less convincing outside this range. A number of potential alternative approaches will be discussed and compared with the experimental results.
New research findings on non-proportional low cycle fatigue
Authors: Cernescu Anghel , Pullin Rhys
Published: December 2019

One of the challenges regarding multiaxial fatigue damage predictions is non-proportional loading. Relevant studies have shown that these multiaxial loadings cause significant additional hardening and reduction in durability due to non-proportionality. Fatigue life predictions due to non-proportional loadings are based on an equivalent non-proportional strain range that considers a material constant related to additional hardening and a non-proportionality factor. In this paper an analysis of the non-proportional factor for three multiaxial loadings forming a square in γ/√3 – ε coordinates is carried out. One of the observations revealed by this analysis is the sensitivity of the non-proportional factor to variable shear strain rate.
Influence of Material Ductility on Fatigue Life under Multiaxial Proportional and Non-Proportional Normal and Shear Stresses
Authors: Sonsino Cetin Morris
Published: December 2019

Current experiences show that a non-proportional loading of ductile materials such as wrought steels, wrought aluminium or magnesium alloys, not welded or welded, causes a significant fatigue life reduction under an out-of-phase shear strain or shear stress superimposed on a normal strain or normal stress compared with proportional in-phase loading. However, when ductility, here characterised by tensile elongation, is reduced by a heat treatment or by another manufacturing technology such as casting or sintering, the afore-mentioned life reduction is compensated or even inversed, i. e. longer fatigue life results compared with proportional loading. Some actual results, determined with additive manufactured titanium, suggest that microstructural features such as manufacturing-dependent internal defects like microporosities should be considered in addition to the ductility level. This complex life behaviour under non-proportional loading cannot always be estimated. Therefore, in experimental proofs of multiaxial loaded parts, especially safety-critical components or structures, with real or service-like signals, emphasis must be placed on retaining non-proportionalities between loads and stresses/strains, respectively.
A universal, damage-criterion-independent cycle counting method for multiaxial and variable amplitude fatigue
Authors: Janssens K.G. F.
Published: December 2019

None of the procedures for cycle-counting defined in the ASTM document with designation E1049-85 (Reapproved 2017) [1] are generally applicable to non-proportional, multi-axial Fatigue. In addition, as the concepts of amplitude and mean stress are defined per cycle, their values are dependent (or co-define) the cycle counting method. This poses an obvious problem to the analysis of non-proportional, multi-axial fatigue damage, as lifetime is, not in all but in many cases, an amplitude and mean stress dependent material property. Most of the newer cycle counting methods developed till date are at least inspired by the works of Wang & Brown [2] and of Bannantine & Socie [3], both of which are themselves still frequently used. Being built inspired by counting methods developed for uniaxial cycling, all of the approaches to date known to this author are limited in a way that is very well phrased by Anes et al [4], whom, on page 79 of their article, write that (quote): The damage criterion is the base stone to set up random fatigue. The damage parameter must capture the fatigue damage behavior to allow set up a cycle counting method and an accumulation model. Challenging this statement, a new cycle counting procedure is presented that is completely independent of the damage criterion, and universally works from the simplest uniaxial experiment, to the most complex, variable amplitude and frequency, non-proportional multiaxial fatigue loading. The definition of this new cycle counting concept is surprisingly simple. Despite of its simplicity, the new cycle counting procedure has diﬀerent advantages when compared to the procedures known to date. Its standalone definition, allows it to be combined with any damage criterion. It does not require periodicity of the loading cycle, and can therefore be straightforwardly used to analyze variable frequency and amplitude, multiaxial fatigue loading.