bluuebunny/crossref_metadata_2025 huggingface dataset:
The future of extreme climate in Iran
Authors: Vaghefi Saeid Ashraf , Keykhai Malihe , Jahanbakhshi Farshid , Sheikholeslami Jaleh , Ahmadi Azadeh , Yang Hong , Abbaspour Karim C.
Published: February 2019

Iran is experiencing unprecedented climate-related problems such as drying of lakes and rivers, dust storms, record-breaking temperatures, droughts, and floods. Here, we use the ensemble of five high-resolution climate models to project maximum and minimum temperatures and rainfall distribution, calculate occurrences of extreme temperatures (temperatures above and below the historical 95th and 5th percentiles, respectively), analyze compound of precipitation and temperature extremes, and determine flooding frequencies across the country. We found that compared to the period of 1980–2004, in the period of 2025–2049, Iran is likely to experience more extended periods of extreme maximum temperatures in the southern part of the country, more extended periods of dry (for ≥120 days: precipitation <2 mm, Tmax ≥30 °C) as well as wet (for ≤3 days: total precipitation ≥110 mm) conditions, and higher frequency of floods. Overall, the combination of these results projects a climate of extended dry periods interrupted by intermittent heavy rainfalls, which is a recipe for increasing the chances of floods. Without thoughtful adaptability measures, some parts of the country may face limited habitability in the future.
Introduction of ‘Generalized Genomic Signatures’ for the quantification of neighbour preferences leads to taxonomy- and functionality-based distinction among sequences
Authors: Apostolou-Karampelis Konstantinos , Polychronopoulos Dimitris , Almirantis Yannis
Published: February 2019

Analysis of DNA composition at several length scales constitutes the bulk of many early studies aimed at unravelling the complexity of the organization and functionality of genomes. Dinucleotide relative abundances are considered an idiosyncratic feature of genomes, regarded as a ‘genomic signature’. Motivated by this finding, we introduce the ‘Generalized Genomic Signatures’ (GGSs), composed of over- and under-abundances of all oligonucleotides of a given length, thus filtering out compositional trends and neighbour preferences at any shorter range. Previous works on alignment-free genomic comparisons mostly rely on k-mer frequencies and not on distance-dependent neighbour preferences. Therein, nucleotide composition and proximity preferences are combined, while in the present work they are strictly separated, focusing uniquely on neighbour relationships. GGSs retain the potential or even outperform genomic signatures defined at the dinucleotide level in distinguishing between taxonomic subdivisions of bacteria, and can be more effectively implemented in microbial phylogenetic reconstruction. Moreover, we compare DNA sequences from the human genome corresponding to protein coding segments, conserved non-coding elements and non-functional DNA stretches. These classes of sequences have distinctive GGSs according to their genomic role and degree of conservation. Overall, GGSs constitute a trait characteristic of the evolutionary origin and functionality of different genomic segments.
Re-evaluation of transcription factor function in tomato fruit development and ripening with CRISPR/Cas9-mutagenesis
Authors: Wang Rufang , Tavano Eveline Carla da Rocha , Lammers Michiel , Martinelli Adriana Pinheiro , Angenent Gerco C. , de Maagd Ruud A.
Published: February 2019

Tomato (Solanum lycopersicum) is a model for climacteric fleshy fruit ripening studies. Tomato ripening is regulated by multiple transcription factors together with the plant hormone ethylene and their downstream effector genes. Transcription Factors APETALA2a (AP2a), NON-RIPENING (NOR) and FRUITFULL (FUL1/TDR4 and FUL2/MBP7) were reported as master regulators controlling tomato fruit ripening. Their proposed functions were derived from studies of the phenotype of spontaneous mutants or RNAi knock-down lines rather than, as it appears now, actual null mutants. To study TF function in tomato fruit ripening in more detail, we used CRISPR/Cas9-mediated mutagenesis to knock out the encoding genes, and phenotypes of these mutants are reported for the first time. While the earlier ripening, orange-ripe phenotype of ap2a mutants was confirmed, the nor null mutant exhibited a much milder phenotype than the spontaneous nor mutant. Additional analyses revealed that the severe phenotype in the spontaneous mutant is caused by a dominant-negative allele. Our approach also provides new insight into the independent and overlapping functions of FUL1 and FUL2. Single and combined null alleles of FUL1 and FUL2 illustrate that these two genes have partially redundant functions in fruit ripening, but also unveil an additional role for FUL2 in early fruit development.
Thermodynamic evidence of magnetic-field-induced complete valley polarization in bismuth
Authors: Iwasa Ayumu , Kondo Akihiro , Kawachi Shiro , Akiba Kazuto , Nakanishi Yoshiki , Yoshizawa Masahito , Tokunaga Masashi , Kindo Koichi
Published: February 2019

We investigated the fundamental physical properties in the ultra-quantum limit state of bismuth through measurements of magnetoresistance, magnetization, magnetostriction, and ultrasound attenuation in magnetic fields up to 60T. For magnetic fields applied along the bisectrix direction of a single crystal, a drastic sign reversal in magnetostriction was observed at approximately 39T, which could be ascribed to the complete valley polarization in the electron Fermi pockets. The application of magnetic fields along the binary direction presented an anomalous feature at approximately 50T only in the magnetoresistance. The emergence of a field-induced splitting of a valley was proposed as a possible origin of this anomaly.
Probing the Inhibition of Microtubule Affinity Regulating Kinase 4 by N-Substituted Acridones
Authors: Voura Maria , Khan Parvez , Thysiadis Savvas , Katsamakas Sotiris , Queen Aarfa , Hasan Gulam Mustafa , Ali Sher , Sarli Vasiliki , Hassan Md. Imtaiyaz
Published: February 2019

Microtubule affinity regulating kinase 4 (MARK4) becomes a unique anti-cancer drug target as its overexpression is responsible for different types of cancers. In quest of novel, effective MARK4 inhibitors, some acridone derivatives were synthesized, characterized and evaluated for inhibitory activity against human MARK4. Among all the synthesized compounds, three (7b, 7dand7f) were found to have better binding affinity and enzyme inhibition activity in µM range as shown by fluorescence binding, ITC and kinase assays. Here we used functional assays of selected potential lead molecules with commercially available panel of 26 kinases of same family. A distinctive kinase selectivity profile was observed for each compound. The selective compounds were identified with submicromolar cellular activity against MARK4. Furthermore,in vitroantitumor evaluation against cancerous cells (MCF-7 and HepG2) revealed that compounds7b, 7dand7finhibit cell proliferation and predominantly induce apoptosis in MCF-7 cells, with IC50values of 5.2 ± 1.2 μM, 6.3 ± 1.2 μM, and 5.8 ± 1.4 μM respectively. In addition, these compounds significantly upsurge the oxidative stress in cancerous cells. Our observations support our approach for the synthesis of effective inhibitors against MARK4 that can be taken forward for the development of novel anticancer molecules targeting MARK4.
Evolution of Pairing Orders between Pseudogap and Superconducting Phases of Cuprate Superconductors
Authors: Tu Wei-Lin , Lee Ting-Kuo
Published: February 2019

One of the most puzzling problems of high temperature cuprate superconductor is the pseudogap phase (PG) at temperatures above the superconducting transition temperature in the underdoped regime. The PG phase is found by the angle-resolved photoemission spectra (ARPES) to have a gap at some regions in momentum space and a fraction of Fermi surface remained, known as Fermi arcs. The arc turns into a d-wave SC gap with a node below the SC transition temperature. Here, by studying a strongly correlated model at low temperatures, we obtained a phase characterized by two kinds of pairing order parameters with the total momentum of the Cooper pair to be zero and finite. The finite momentum pairing is accompanied with a spatial modulation of pairing order, i.e. a pair density wave (PDW). These PDW phases are intertwined with modulations of charge density and intra-unit cell form factors. The coexistence of the two different pairing orders provides the unique two-gaps like spectra observed by ARPES for superconducting cuprates. As temperature raises, the zero-momentum pairing order vanishes while the finite momentum pairing orders are kept, thus Fermi arcs are realized. The calculated quasiparticle spectra have the similar doping and temperature dependence as reported by ARPES and scanning tunneling spectroscopy (STS). The consequence of breaking symmetry between x and y due to the unidirectional PDW and the possibility to probe such a PDW state in the PG phase is discussed.
Ionic current correlations are ubiquitous across phyla
Authors: Tran Trinh , Unal Cagri T. , Severin Daniel , Zaborszky Laszlo , Rotstein Horacio G. , Kirkwood Alfredo , Golowasch Jorge
Published: February 2019

Ionic currents, whether measured as conductance amplitude or as ion channel transcript numbers, can vary many-fold within a population of identified neurons. In invertebrate neuronal types multiple currents can be seen to vary while at the same time their magnitudes are correlated. These conductance amplitude correlations are thought to reflect a tight homeostasis of cellular excitability that enhances the robustness and stability of neuronal activity over long stretches of time. Although such ionic conductance correlations are well documented in invertebrates, they have not been reported in vertebrates. Here we demonstrate with two examples, identified mouse hippocampal granule cells (GCs) and cholinergic basal forebrain neurons, that the correlation of ionic conductance amplitudes between different ionic currents also exists in vertebrates, and we argue that it is a ubiquitous phenomenon expressed by many species across phyla. We further demonstrate that in dentate gyrus GCs these conductance correlations are likely regulated in a circadian manner. This is reminiscent of the known conductance regulation by neuromodulators in crustaceans. However, in GCs we observe a more nuanced regulation, where for some conductance pairs the correlations are completely eliminated while for others the correlation is quantitatively modified but not obliterated.
The discovery of Lake Hephaestus, the youngest athalassohaline deep-sea formation on Earth
Authors: La Cono Violetta , Bortoluzzi Giovanni , Messina Enzo , La Spada Gina , Smedile Francesco , Giuliano Laura , Borghini Mireno , Stumpp Christine , Schmitt-Kopplin Philippe , Harir Mourad , O’Neill William K. , Hallsworth John E. , Yakimov Michail
Published: February 2019

Hydrated, magnesium-rich minerals and subglacial brines exist on the martian surface, so the habitability of high-Mg2+ environments on Earth has extraterrestrial (as well as terrestrial) implications. Here, we report the discovery of a MgCl2-dominated (4.72 M) brine lake on the floor of the Mediterranean Ridge that underlies a 3500-m water column, and name it Lake Hephaestus. Stable isotope analyses indicated that the Hephaestus brine is derived from interactions between ancient bishofite-enriched evaporites and subsurface fluids. Analyses of sediment pore waters indicated that the Hephaestus depression had contained the MgCl2 brine for a remarkably short period; only 700 years. Lake Hephaestus is, therefore, the youngest among currently known submarine athalassohaline brine lakes on Earth. Due to its biologically hostile properties (low water-activity and extreme chaotropicity), the Hephaestus brine is devoid of life. By contrast, the seawater-Hephaestus brine interface has been shown to act as refuge for extremely halophilic and magnesium-adapted stratified communities of microbes, even at MgCl2 concentrations that approach the water-activity limit for life (0.653).
Precise U-Pb age constrains on the Ediacaran biota in Podolia, East European Platform, Ukraine
Authors: Soldatenko Y. , El Albani A. , Ruzina M. , Fontaine C. , Nesterovsky V. , Paquette J.-L. , Meunier A. , Ovtcharova M.
Published: February 2019

The Neoproterozoic Era was characterized by rapidly changing paleogeography, global climate changes and especially by the rise and fall of the Ediacaran macro-biota. The correlation between disparate Ediacaran fossil-bearing localities and the tentative reconstruction of their paleoenvironmental and paleogeographic contexts are usually complicated by the lack of precise and accurate age data. For this reason, Neoproterozoic sedimentary sections associating Ediacaran biota fossils and fresh volcanic material are especially valuable for radioisotopic dating. Our research in the Podolya Basin, southwestern Ukraine, revealed the presence of four Neoproterozoic volcanic ash deposits (potassium-bentonite layers) within Ediacaran fossil-bearing siliciclastic rocks of the Mohyliv-Podilskyi Group. We used zircon U-Pb LA-ICPMS and CA-ID-TIMS methods to date two of those layers. The results indicate that a diverse assemblage of body and trace Ediacaran fossils occurred as early as 556.78 ± 0.18 million years (Ma) ago. By combining morphological evidence and new age determinations, we suggest a closer paleobiogeographical relationship between the Ukrainian Ediacaran assemblage and the Avalon paleocontinent than previously estimated.
Skeletal Anomalies in The Neandertal Family of El Sidrón (Spain) Support A Role of Inbreeding in Neandertal Extinction
Authors: Ríos L. , Kivell T. L. , Lalueza-Fox C. , Estalrrich A. , García-Tabernero A. , Huguet R. , Quintino Y. , de la Rasilla M. , Rosas A.
Published: February 2019

Neandertals disappeared from the fossil record around 40,000 bp, after a demographic history of small and isolated groups with high but variable levels of inbreeding, and episodes of interbreeding with other Paleolithic hominins. It is reasonable to expect that high levels of endogamy could be expressed in the skeleton of at least some Neandertal groups. Genetic studies indicate that the 13 individuals from the site of El Sidrón, Spain, dated around 49,000 bp, constituted a closely related kin group, making these Neandertals an appropriate case study for the observation of skeletal signs of inbreeding. We present the complete study of the 1674 identified skeletal specimens from El Sidrón. Altogether, 17 congenital anomalies were observed (narrowing of the internal nasal fossa, retained deciduous canine, clefts of the first cervical vertebra, unilateral hypoplasia of the second cervical vertebra, clefting of the twelfth thoracic vertebra, diminutive thoracic or lumbar rib, os centrale carpi and bipartite scaphoid, tripartite patella, left foot anomaly and cuboid-navicular coalition), with at least four individuals presenting congenital conditions (clefts of the first cervical vertebra). At 49,000 years ago, the Neandertals from El Sidrón, with genetic and skeletal evidence of inbreeding, could be representative of the beginning of the demographic collapse of this hominin phenotype.
Validation and quality assessment of macromolecular structures using complex network analysis
Authors: Pražnikar Jure , Tomić Miloš , Turk Dušan
Published: February 2019

Validation of three-dimensional structures is at the core of structural determination methods. The local validation criteria, such as deviations from ideal bond length and bonding angles, Ramachandran plot outliers and clashing contacts, are a standard part of structure analysis before structure deposition, whereas the global and regional packing may not yet have been addressed. In the last two decades, three-dimensional models of macromolecules such as proteins have been successfully described by a network of nodes and edges. Amino acid residues as nodes and close contact between the residues as edges have been used to explore basic network properties, to study protein folding and stability and to predict catalytic sites. Using complex network analysis, we introduced common network parameters to distinguish between correct and incorrect three-dimensional protein structures. The analysis showed that correct structures have a higher average node degree, higher graph energy, and lower shortest path length than their incorrect counterparts. Thus, correct protein models are more densely intra-connected, and in turn, the transfer of information between nodes/amino acids is more efficient. Moreover, protein graph spectra were used to investigate model bias in protein structure.
Antifungal activity and mechanism of action of Ou-gon (Scutellaria root extract) components against pathogenic fungi
Authors: Da Xia , Nishiyama Yayoi , Tie Duerna , Hein Kyaw Zaw , Yamamoto Osamu , Morita Eishin
Published: February 2019

Ou-gon, an extract fromScutellaria baicalensisGeorgi root, has been shown to exhibit pronounced antifungal activity. The present study aimed to identify antifungal components of Ou-gon and to determine their mechanism of action against pathogenic fungi. Antifungal activity was assessed by the microbroth dilution method using four common human pathogenic fungi,Trichophyton rubrum,Trichophyton mentagrophytes,Aspergillus fumigatus, andCandida albicans. Components of crude Ou-gon extract were separated by reversed-phase high-performance liquid chromatography. Active antifungal components were identified by liquid chromatography-electrospray ionization tandem mass spectrometry. Terminal deoxynucleotidyl transferase dUTP nick end-labelling assay, SYTOX®green uptake assay, determination of intracellular reactive oxygen species and mitochondrial membrane potential as well as microscopy (confocal laser microscopy, scanning and transmission electron microscopy) were used to probe the mode of action. Two components with potent antifungal activity, baicalein and wogonin, were identified in Ou-gon. Baicalein showed potent antifungal activity against the four fungi tested. Wogonin displayed antifungal activity against all four fungi exceptC. albicans. The components are considered to induce apoptosis-like programmed cell death via hyperproduction of reactive oxygen species. This study enhances our understanding of the antifungal activity of Kampo medicine, and may contribute to the development of new and safe antifungal therapeutics.
A Novel Ruthenium-based Molecular Sensor to Detect Endothelial Nitric Oxide
Authors: Vidanapathirana Achini K. , Pullen Benjamin J. , Zhang Run , Duong MyNgan , Goyne Jarrad M. , Zhang Xiaozhou , Bonder Claudine S. , Abell Andrew D. , Bursill Christina A. , Nicholls Stephen J. , Psaltis Peter J.
Published: February 2019

Nitric oxide (NO) is a key regulator of endothelial cell and vascular function. The direct measurement of NO is challenging due to its short half-life, and as such surrogate measurements are typically used to approximate its relative concentrations. Here we demonstrate that ruthenium-based [Ru(bpy)2(dabpy)]2+ is a potent sensor for NO in its irreversible, NO-bound active form, [Ru(bpy)2(T-bpy)]2+. Using spectrophotometry we established the sensor’s ability to detect and measure soluble NO in a concentration-dependent manner in cell-free media. Endothelial cells cultured with acetylcholine or hydrogen peroxide to induce endogenous NO production showed modest increases of 7.3 ± 7.1% and 36.3 ± 25.0% respectively in fluorescence signal from baseline state, while addition of exogenous NO increased their fluorescence by 5.2-fold. The changes in fluorescence signal were proportionate and comparable against conventional NO assays. Rabbit blood samples immediately exposed to [Ru(bpy)2(dabpy)]2+ displayed 8-fold higher mean fluorescence, relative to blood without sensor. Approximately 14% of the observed signal was NO/NO adduct-specific. Optimal readings were obtained when sensor was added to freshly collected blood, remaining stable during subsequent freeze-thaw cycles. Clinical studies are now required to test the utility of [Ru(bpy)2(dabpy)]2+ as a sensor to detect changes in NO from human blood samples in cardiovascular health and disease.
Haemolymph microbiome of the cultured spiny lobster Panulirus ornatus at different temperatures
Authors: Ooi Mei C. , Goulden Evan F. , Smith Gregory G. , Bridle Andrew R.
Published: February 2019

Lobsters have an open circulatory system with haemolymph that contains microorganisms even in the healthy individuals. Understanding the role of these microorganisms becomes increasingly important particularly for the diagnosis of disease as the closed life-cycle aquaculture of the spiny lobsterPanulirus ornatusnears commercial reality. This study aimed to characterise haemolymph responses of healthy culturedP.ornatusjuveniles at control (28 °C) and elevated (34 °C) temperatures. This was assessed by measuring immune parameters (total granulocyte counts, total haemocyte counts, clotting times), and culture-independent (pyrosequencing of haemolymph DNA) and culture-dependent (isolation using nonselective growth medium) techniques to analyse bacterial communities from lobster haemolymph sampled on days 0, 4 and 6 post-exposure to the temperature regimes. Elevated temperature (34 °C) affected lobster survival, total granulocyte counts, and diversity, load and functional potential of the haemolymph bacterial community. Pyrosequencing analyses showed that the core haemolymph microbiome consisted of phyla Proteobacteria and Bacteriodetes. Overall, culture-independent methods captured a higher bacterial diversity and load when compared to culture-dependent methods, however members of theRhodobacteraceaewere strongly represented in both analyses. This is the first comprehensive study providing comparisons of haemolymph bacterial communities from healthy and thermally stressed cultured juvenileP.ornatusand has the potential to be used in health monitoring programs.
History and Development of Nucleotide Analogues in Nucleic Acids Drugs
Authors: Agrawal Sudhir , Gait Michael J.
Published: February 2019

The nucleic acid-based drug discovery approach is now being recognized as a major platform in addition to small molecules and peptide- or protein-based platforms. Advancement in nucleic acid based drugs has been aided by the chemistry of oligonucleotides and nucleic acids in providing drug-like properties. Early experience was gained with respect to the use of the chemistry of oligonucleotides for use as antisense agents. These chemical structure–activity relationship studies included modification of the backbone, heterocyclic bases and sugars, or combinations thereof. In this chapter we discuss early developments in the chemistry of nucleic acids that have guided the design and successful development of antisense drugs as well as nucleic acid-based platforms employing many other mechanisms, including aptamers, siRNA, exon skipping, ribozyme, microRNA and non-coding RNA and immune modulation.
Prostate-specific Membrane Antigen (PSMA) Aptamers for Prostate Cancer Imaging and Therapy
Authors: Shubham Shambhavi , Lin Li-Hsien , Udofot Ofonime , Krupse Sven , Giangrande Paloma H.
Published: February 2019

Current therapies for advanced-stage prostate cancer have shown limited efficacy due to the molecular complexity of this aggressive disease and the unwanted side effects that result from the treatments themselves. Chemotherapeutic drug cocktails are currently the preferred treatment option to inhibit multiple targets simultaneously, thereby reducing drug-resistance in advanced-stage disease. However, owing to the non-selective nature of these drugs, targeted approaches that eliminate toxicity to non-target tissues and reduce the amount of drug that needs to be administered to the patient are warranted. Prostate-specific membrane antigen (PSMA), a transmembrane receptor expressed on malignant prostate cancer cells, has been identified as a promising therapeutic target for targeted therapy of prostate cancer. PSMA-targeted agents have included small molecules, antibodies, and nucleic acid aptamers. This review focuses on oligonucleotide-based ligands (DNA and RNA aptamers) that target PSMA and their use in imaging and therapeutic applications for prostate cancer. This review covers important concepts pertaining to the clinical translation of PSMA aptamers (safety, stability, and pharmacokinetics) and highlight existing hurdles and future prospects.
Systemic administration of enzyme-responsive growth factor nanocapsules for promoting bone repair
Authors: Qi Hongzhao , Yang Lijun , Li Xueping , Sun Xiaolei , Zhao Jin , Hou Xin , Li Zhaoyang , Yuan Xubo , Cui Zhenduo , Yang Xianjin
Published: February 2019

Taking the advantages of the unique physiological character of bone fracture, a systemic delivery platform of growth factors for bone repair based on nanocapsules was exploited.
Ratiometric detection of heavy metal ions using fluorescent carbon dots
Authors: Yarur Francisco , Macairan Jun-Ray , Naccache Rafik
Published: February 2019

Classical methods for the detection of heavy metal ions in water are tedious and time consuming.
Influence of carbonaceous species on aqueous photo-catalytic nitrogen fixation by titania
Authors: Liu Yu-Hsuan , Vu Manh Hiep , Lim JeongHoon , Do Trong-On , Hatzell Marta C.
Published: February 2019

We tested an emerging hypothesis that carbon species may play an integral role in catalyzing dinitrogen adsorption and reduction to ammonia.
Charging toward improved lithium-ion polymer electrolytes: exploiting synergistic experimental and computational approaches to facilitate materials design
Authors: Ketkar Priyanka M. , Shen Kuan-Hsuan , Hall Lisa M. , Epps Thomas H.
Published: February 2019

Lithium-ion battery performance is governed by ionic transport mechanisms over a wide range of size scales.
Two-dimensional nonlinear optical materials predicted by network visualization
Authors: Yang Guoyu , Wu Kechen
Published: February 2019

Machine learning and network visualization were applied to predict two-dimensional nonlinear optical materials by selecting key elements and connections.
The role of charge-matching in nanoporous materials formation
Authors: Centi Alessia , Manning Joseph R. H. , Srivastava Vibha , van Meurs Sandra , Patwardhan Siddharth V. , Jorge Miguel
Published: February 2019

Multi-scale modelling and experiments show that self-assembly of amine-templated silica occurs through charge-matching and not through the accepted neutral-templating mechanism.
Encapsulating an organic phase change material within emulsion-templated poly(urethane urea)s
Authors: Weinstock Liora , Sanguramath Rajashekharayya A. , Silverstein Michael S.
Published: February 2019

Interfacial step growth polymerization within oil-in-water high internal phase emulsions was used to synthesize poly(urethane urea) monoliths, consisting of 90% organic phase change material encapsulated within micrometer-scale capsules, for thermal energy storage and release applications.
Improving the flame retardancy of polyethylenes through the palladium-catalyzed incorporation of polar comonomers
Authors: Gao Jiaxin , Cai Wei , Hu Yuan , Chen Changle
Published: February 2019

The flame retardancy of polyethylenes can be efficiently improved through the palladium catalyzed copolymerization of ethylene with polar comonomers.
Cp*Co(iii)-catalyzed N-alkylation of amines with secondary alcohols
Authors: Emayavaramban Balakumar , Chakraborty Priyanka , Manoury Eric , Poli Rinaldo , Sundararaju Basker
Published: February 2019

We report here the first high-valent cobalt(iii)-catalyzed direct alkylation of aromatic amines with secondary alcohols.
Manipulating thermal resistance at the solid–fluid interface through monolayer deposition
Authors: Hasan Mohammad Rashedul , Vo Truong Quoc , Kim BoHung
Published: February 2019

At the interface between monolayer coated solid substrate and fluid, the effect of interfacial mismatch on Kapitza length due to the monolayer particles has been extensively analyzed through a series of non-equilibrium molecular dynamics simulation.
ASK1-p38 cascaded signal mediates pulmonary microvascular endothelial barrier injury induced by the return of PHSML in rats
Authors: Fawad Muhammad , Abbas Muhammad , Zhang Limin , Zhang Yuping , Guo Yaxiong
Published: February 2019

The return of post-hemorrhagic shock mesenteric lymph (PHSML) induces pulmonary vascular endothelial barrier dysfunction, which results in acute lung injury.
Aggregation-induced chiroptical generation and photoinduced switching of achiral azobenzene-alt-fluorene copolymer endowed with left- and right-handed helical polysilanes
Authors: Chen Hailing , Yin Lu , Liu Meng , Wang Laibing , Fujiki Michiya , Zhang Wei , Zhu Xiulin
Published: February 2019

The helicity of PF8Azo was successfully induced by UV-decomposable chiral polysilanes, and PF8Azo/PSi-S and PF8Azo/PSi-R hetero-aggregates were subjected to trans–cis photoisomerization.
Discovery of trisubstituted nicotinonitrile derivatives as novel human GCN5 inhibitors through AlphaScreen-based high throughput screening
Authors: Tao Hongru , Wang Jun , Lu Wenchao , Zhang Rukang , Xie Yiqian , Liu Yu-Chih , Liu Rongfeng , Yue Liyan , Chen Kaixian , Jiang Hualiang , Zhang Yuanyuan , Xu Xiaohui , Luo Cheng
Published: February 2019

The trisubstituted nicotinonitrile derivative DC_HG24-01 was discovered as a novel potent hGCN5 inhibitor with efficient bioactivity against MV4-11 cells.
Plasmonic nanomaterial structuring for SERS enhancement
Authors: Purwidyantri Agnes , Hsu Chih-Hsien , Yang Chia-Ming , Prabowo Briliant Adhi , Tian Ya-Chung , Lai Chao-Sung
Published: February 2019

Au island over nanospheres (AuIoN) structures featuring a three-dimensional (3D) nanostructure on a two-dimensional (2D) array of nanospheres with different adhesion layers were fabricated as surface-enhanced Raman scattering (SERS) substrates.
Charge polarization near dielectric interfaces and the multiple-scattering formalism
Authors: Qin Jian
Published: February 2019

Reviewing the impacts of interfacial charges on the cohesive energy, permittivity, and singular contact charge for polarizable dielectric particles.
Zr doped mesoporous LaTaON2 for efficient photocatalytic water splitting
Authors: Wang Yawei , Jin Shu , Pan Guoxiang , Li Zuxin , Chen Long , Liu Gang , Xu Xiaoxiang
Published: February 2019

Zr doping maintains the visible light absorption of LaTaON2 and contributes to enhanced photocatalytic activities for water splitting.
N-doped porous transition metal-based carbon nanosheet networks as a multifunctional electrocatalyst for rechargeable zinc–air batteries
Authors: Ding Jieting , Ji Shan , Wang Hui , Gai Hengjun , Liu Fusheng , Pollet Bruno G. , Wang Rongfang
Published: February 2019

The development of cost-effective and highly efficient multi-functional oxygen reduction reaction and oxygen evolution reaction catalysts has attracted much research attention due to their great potential applications in many advanced clean energy storage and conversion technologies.
Correction: Environmental transformation of natural and engineered carbon nanoparticles and implications for the fate of organic contaminants
Authors: Sigmund Gabriel , Jiang Chuanjia , Hofmann Thilo , Chen Wei
Published: February 2019

Correction for ‘Environmental transformation of natural and engineered carbon nanoparticles and implications for the fate of organic contaminants’ by Gabriel Sigmund et al., Environ. Sci.: Nano, 2018, 5, 2500–2518.
Synthesis and antitumor activities of aquayamycin and analogues of derhodinosylurdamycin A
Authors: Acharya Padam P. , Khatri Hem Raj , Janda Sandip , Zhu Jianglong
Published: February 2019

An analogue without the sugar moiety of natural derhodinosylurdamycin A is better.
tert-Butyl nitrite-mediated radical cyclization of tetrazole amines and alkynes toward tetrazolo[1,5-a]quinolines
Authors: Liu Teng , Ji Yi-Gang , Wu Lei
Published: February 2019

A general and efficient radical cyclization of 1H-tetrazol-5-amines and alkynes toward tetrazolo[1,5-a]quinolines is established for the first time.
Preparation, crystal structure and luminescence properties of a novel single-phase red emitting phosphor CaSr2(PO4)2:Sm3+,Li+
Authors: Chen Yuying , Guo Qingfeng , Liao Libing , He Mingyue , Zhou Tianshuai , Mei Lefu , Runowski Marcin , Ma Bin
Published: February 2019

Single-phase red emitting CaSr2(PO4)2:Sm3+,Li+ phosphors with good thermal stability were obtained.
Substrate reduction therapy for inborn errors of metabolism
Authors: Yue Wyatt W. , Mackinnon Sabrina , Bezerra Gustavo A.
Published: February 2019

Inborn errors of metabolism (IEM) represent a growing group of monogenic disorders each associated with inherited defects in a metabolic enzyme or regulatory protein, leading to biochemical abnormalities arising from a metabolic block. Despite the well-established genetic linkage, pathophysiology and clinical manifestations for many IEMs, there remains a lack of transformative therapy. The available treatment and management options for a few IEMs are often ineffective or expensive, incurring a significant burden to individual, family, and society. The lack of IEM therapies, in large part, relates to the conceptual challenge that IEMs are loss-of-function defects arising from the defective enzyme, rendering pharmacologic rescue difficult. An emerging approach that holds promise and is the subject of a flurry of pre-/clinical applications, is substrate reduction therapy (SRT). SRT addresses a common IEM phenotype associated with toxic accumulation of substrate from the defective enzyme, by inhibiting the formation of the substrate instead of directly repairing the defective enzyme. This minireview will summarize recent highlights towards the development of emerging SRT, with focussed attention towards repurposing of currently approved drugs, approaches to validate novel targets and screen for hit molecules, as well as emerging advances in gene silencing as a therapeutic modality.
Thermal analysis of power transformers under unbalanced supply voltage
Authors: Mikha‐Beyranvand Morteza , Faiz Jawad , Rezaeealam Behrooz , Rezaei‐Zare Afshin , Jafarboland Mehrdad
Published: February 2019

High temperatures may damage power transformers. These problems leading to the high temperature are more revealed under non‐rating operating conditions such as unbalanced supply voltage. The aim of the present study is thermal analysis of such supply and obtaining its temperature distribution. Existing thermal analysis methods through thermal equivalent circuit (TEC) have some drawbacks; in these models, thermal parameters of different regions of transformer such as core, tank, metallic parts and winding are not defined. On the other hand, those models are not applicable for thermal analysis of transformer with unbalanced supply voltage. Here, a novel TEC model is proposed which is able to define temperatures of different components of oil‐immersed power transformers individually under unbalanced supply voltage. The merit of the introduced model is that losses of different parts of transformer are considered as heat generating sources which are used as the inputs of thermal model. At this end, a three‐dimensional finite‐element method is suggested which is able to estimate the losses of different parts of power transformer. Finally, the results of applying the TEC to the transformer are compared with the temperature distribution of finite‐element modelling and high accuracy of the TEC model in estimation of the temperatures of different regions are emphasised.
ATLASGAL-selected massive clumps in the inner Galaxy
Authors: Navarete F. , Leurini S. , Giannetti A. , Wyrowski F. , Urquhart J. S. , König C. , Csengeri T. , Güsten R. , Damineli A. , Menten K. M.
Published: February 2019

Context. High-mass stars are formed within massive molecular clumps, where a large number of stars form close together. The evolution of the clumps with different masses and luminosities is mainly regulated by their high-mass stellar content and the formation of such objects is still not well understood.

Aims. In this work, we characterise the mid-J CO emission in a statistical sample of 99 clumps (TOP100) selected from the ATLASGAL survey that are representative of the Galactic proto-cluster population.

Methods. High-spatial resolution APEX-CHAMP+ maps of the CO (6–5) and CO (7–6) transitions were obtained and combined with additional single-pointing APEX-FLASH+ spectra of the CO (4–3) line. The data were convolved to a common angular resolution of 13.′′4. We analysed the line profiles by fitting the spectra with up to three Gaussian components, classified as narrow or broad, and computed CO line luminosities for each transition. Additionally, we defined a distance-limited sample of 72 sources within 5 kpc to check the robustness of our analysis against beam dilution effects. We have studied the correlations of the line luminosities and profiles for the three CO transitions with the clump properties and investigate if and how they change as a function of the evolution.

Results. All sources were detected above 3-σ in all three CO transitions and most of the sources exhibit broad CO emission likely associated with molecular outflows. We find that the extension of the mid-J CO emission is correlated with the size of the dust emission traced by the Herschel-PACS 70 μm maps. The CO line luminosity (LCO) is correlated with the luminosity and mass of the clumps. However, it does not correlate with the luminosity-to-mass ratio.

Conclusions. The dependency of the CO luminosity with the properties of the clumps is steeper for higher-J transitions. Our data seem to exclude that this trend is biased by self-absorption features in the CO emission, but rather suggest that different J transitions arise from different regions of the inner envelope. Moreover, high-mass clumps show similar trends in CO luminosity as lower mass clumps, but are systematically offset towards larger values, suggesting that higher column density and (or) temperature (of unresolved) CO emitters are found inside high-mass clumps.
Organic molecules in the protoplanetary disk of DG Tauri revealed by ALMA
Authors: Podio L. , Bacciotti F. , Fedele D. , Favre C. , Codella C. , Rygl K. L. J. , Kamp I. , Guidi G. , Bianchi E. , Ceccarelli C. , Coffey D. , Garufi A. , Testi L.
Published: February 2019

Context. Planets form in protoplanetary disks and inherit their chemical compositions.

Aims. It is thus crucial to map the distribution and investigate the formation of simple organics, such as formaldehyde and methanol, in protoplanetary disks.

Methods. We analyze ALMA observations of the nearby disk-jet system around the T Tauri star DG Tau in the o − H2CO 31, 2 − 21, 1 and CH3OH 3−2, 2 − 4−1, 4 E, 50, 5 − 40, 4 A transitions at an unprecedented resolution of $ {\sim}0{{\overset{\prime\prime}{.}}}{15} $, i.e., ∼18 au at a distance of 121 pc.

Results. The H2CO emission originates from a rotating ring extending from ∼40 au with a peak at ∼62 au, i.e., at the edge of the 1.3 mm dust continuum. CH3OH emission is not detected down to an rms of 3 mJy beam−1 in the 0.162 km s−1 channel. Assuming an ortho-to-para ratio of 1.8−2.8 the ring- and disk-height-averaged H2CO column density is ∼0.3−4 × 1014 cm−2, while that of CH3OH is < 0.04−0.7 × 1014 cm−2. In the inner 40 au no o − H2CO emission is detected with an upper limit on its beam-averaged column density of ∼0.5−6 × 1013 cm−2.

Conclusions. The H2CO ring in the disk of DG Tau is located beyond the CO iceline (RCO ∼ 30 au). This suggests that the H2CO abundance is enhanced in the outer disk due to formation on grain surfaces by the hydrogenation of CO ice. The emission peak at the edge of the mm dust continuum may be due to enhanced desorption of H2CO in the gas phase caused by increased UV penetration and/or temperature inversion. The CH3OH/H2CO abundance ratio is < 1, in agreement with disk chemistry models. The inner edge of the H2CO ring coincides with the radius where the polarization of the dust continuum changes orientation, hinting at a tight link between the H2CO chemistry and the dust properties in the outer disk and at the possible presence of substructures in the dust distribution.
Analytic solutions to the maximum and average exoplanet transit depth for common stellar limb darkening laws
Authors: Heller René
Published: February 2019

Context. The depth of an exoplanetary transit in the light curve of a distant star is commonly approximated as the squared planet-to-star radius ratio, (Rp/Rs)2. Stellar limb darkening, however, can result in significantly deeper transits. An analytic solution would be worthwhile to illustrate the principles of the problem and predict the actual transit signal required for the planning of transit observations with certain signal-to-noise requirements without the need of computer-based transit simulations.

Aims. We calculate the overshoot of the mid-transit depth caused by stellar limb darkening compared to the (Rp/Rs)2 estimate for arbitrary transit impact parameters. In turn, this allows us to compute the true planet-to-star radius ratio from the transit depth for a given parameterization of a limb darkening law and for a known transit impact parameter.

Methods. We compute the maximum emerging specific stellar intensity covered by the planet in transit and derive analytic solutions for the transit depth overshoot. Solutions are presented for the linear, quadratic, square-root, logarithmic, and nonlinear stellar limb darkening with arbitrary transit impact parameters. We also derive formulae to calculate the average intensity along the transit chord, which allows us to estimate the actual transit depth (and therefore Rp∕Rs) from the mean in-transit flux.

Results. The transit depth overshoot of exoplanets compared to the (Rp/Rs)2 estimate increases from about 15% for main-sequence stars of spectral type A to roughly 20% for sun-like stars and some 30% for K and M stars. The error in our analytical solutions for Rp∕Rs from the small planet approximation is orders of magnitude smaller than the uncertainties arising from typical noise in real light curves and from the uncertain limb darkening.

Conclusions. Our equations can be used to predict with high accuracy the expected transit depth of extrasolar planets. The actual planet radius can be calculated from the measured transit depth or from the mean in-transit flux if the stellar limb darkening can be properly parameterized and if the transit impact parameter is known. Light curve fitting is not required.
A deep XMM-Newton look on the thermally emitting isolated neutron star RX J1605.3+3249
Authors: Pires A. M. , Schwope A. D. , Haberl F. , Zavlin V. E. , Motch C. , Zane S.
Published: February 2019

Previous XMM-Newton observations of the thermally emitting isolated neutron star RX J1605.3+3249 provided a candidate for a shallow periodic signal and evidence of a fast spin down, which suggested a high dipolar magnetic field and an evolution from a magnetar. We obtained a large programme with XMM-Newton to confirm its candidate timing solution, understand the energy-dependent amplitude of the modulation, and investigate the spectral features of the source. We performed extensive high-resolution and broadband periodicity searches in the new observations, using the combined photons of the three EPIC cameras and allowing for moderate changes of pulsed fraction and the optimal energy range for detection. We also investigated the EPIC and RGS spectra of the source with unprecedented statistics and detail. A deep 4σ upper limit of 1.33(6)% for modulations in the relevant frequency range conservatively rules out the candidate period previously reported. Blind searches revealed no other periodic signal above the 1.5% level (3σ; P >  0.15 s; 0.3–1.35 keV) in any of the four new observations. While theoretical models fall short at physically describing the complex energy distribution of the source, best-fit X-ray spectral parameters are obtained for a fully or partially ionized neutron star hydrogen atmosphere model with B = 1013 G, modified by a broad Gaussian absorption line at energy ϵ = 385 ± 10 eV. A double-temperature blackbody model, although a good fit to the source spectrum, is disfavoured as it would require a particularly improbable viewing geometry to explain the lack of X-ray pulsations associated with small hotspots on the surface of the neutron star. We identified a low significance (1σ) temporal trend on the parameters of the source in the analysis of RGS data dating back to 2002, which may be explained by unaccounted calibration issues and spectral model uncertainties. The new dataset also shows no evidence of the previously reported narrow absorption feature at ϵ ∼ 570 eV, whose possible transient nature disfavours an atmospheric origin.
Mathematical modeling of agglomerates evolution
Authors: Babuk V.A. , Budnyi N.L. , Nizyaev A.A.
Published: February 2019

The model of evolution of the condensed products as a part of a flow of combustion products of solid propellant is developed. The model includes the description of physical and chemical transformations for two basic fractions of the condensed products: agglomerates and smoke oxide particles (SOPs). Model testing is carried out using experimental data about evolution of the condensed products for two compositions in the conditions of a one-dimensional flow. These compositions differ considerably in properties of combustion products at a surface of burning propellant. The results of testing give the grounds to draw a conclusion about high enough quality of modeling.
Modeling of H2/O2 single-element rocket thrust chamber combustion at sub- and supercritical pressures with different computational fluid dynamics tools
Authors: Riedmann H. , Banuti D. , Ivancic B. , Knab O. , Hannemann K.
Published: February 2019

This paper derives from the cooperation between DLR and Airbus DS within the work package “CFD Modeling of Combustion Chamber Processes” conducted in the frame of the Propulsion 2020 project. In a joint strategy, DLR Göttingen and Airbus DS Ottobrunn have identified a number of test cases with gradually growing complexity where adequate test data are available for proper successive validation of the computational fluid dynamics (CFD) tools to be used in an industrial environment. This work highlights the simulation results for the Mascotte A-10 and A-60 test cases as presented at the 2nd International Workshop on Rocket Combustion Modeling in Lampoldshausen 2001 by ONERA and SNECMA [1]. These two test cases are characterized by different chamber pressures (10 and 60 bar) and, consequently, by oxygen injection conditions which are subcritical in one case and transcritical in the other case. The test cases are treated with three different CFD codes: the DLR TAU Code (only A-60 case), the Airbus DS in-house tool Rocflam3, and the commercial CFD tool ANSYS CFX incorporating several modeling extensions by Airbus DS. To the knowledge of the authors, this paper is the first one which covers both the A-10 and the A-60 test cases.
Flame response to high-frequency oscillations in a cryogenic oxygen/hydrogen rocket combustor
Authors: Fdida N. , Hardi J. , Kawashima H. , Knapp B. , Oschwald M. , Ristori A.
Published: February 2019

Experiments presented in this paper were conducted with the BKH rocket combustor at the European Research and Technology Test Facility P8, located at DLR Lampoldshausen. This combustor is dedicated to study the effects of high magnitude instabilities on oxygen/hydrogen flames, created by forcing high-frequency (HF) acoustic resonance of the combustion chamber. This work addresses the need for highly temporally and spatially resolved visualization data, in operating conditions representative of real rocket engines, to better understand the flame response to high amplitude acoustic oscillations. By combining ONERA and DLR materials and techniques, the optical setup of this experiment has been improved to enhance the existing database with more highly resolved OH* imaging to allow detailed response analysis of the flame. OH* imaging is complemented with simultaneous visible imaging and compared to each other here for their ability to capture flame dynamics.