bluuebunny/crossref_metadata_2025 huggingface dataset:
Rhodium‐Catalyzed [2+1+2+1] Cycloaddition of Benzoic Acids with Diynes through Decarboxylation and C≡C Triple Bond Cleavage
Authors: Honjo Yusaku , Shibata Yu , Tanaka Ken
Published: April 2019

It has been established that an electron‐deficient cyclopentadienyl rhodium(III) (CpERhIII) complex catalyzes the oxidative and decarboxylative [2+1+2+1] cycloaddition of benzoic acids with diynes through C≡C triple bond cleavage, leading to fused naphthalenes. This cyclotrimerization is initiated by directed ortho C−H bond cleavage of a benzoic acid, and the subsequent regioselective alkyne insertion and decarboxylation produce a five‐membered rhodacycle. The electron‐deficient nature of the CpERhIII complex promotes reductive elimination giving a cyclobutadiene–rhodium(I) complex rather than the second intermolecular alkyne insertion. The oxidative addition of the thus generated cyclobutadiene to rhodium(I) (formal C≡C triple bond cleavage) followed by the second intramolecular alkyne insertion and reductive elimination give the corresponding [2+1+2+1] cycloaddition product. The synthetic utility of the present [2+1+2+1] cycloaddition was demonstrated in the facile synthesis of a donor–acceptor [5]helicene and a hemi‐hexabenzocoronene by a combination with the chemoselective Scholl reaction.
Nuclear microsatellite and mitochondrial DNA analyses reveal the regional genetic structure and phylogeographical history of a sanguivorous land leech, Haemadipsa japonica, in Japan
Authors: Morishima Kaori , Aizawa Mineaki
Published: April 2019

Recent molecular studies have indicated that phylogeographical history of Japanese biota is likely shaped by geohistory along with biological events, such as distribution shifts, isolation, and divergence of populations. However, the genetic structure and phylogeographical history of terrestrial Annelida species, including leech species, are poorly understood. Therefore, we aimed to understand the genetic structure and phylogeographical history across the natural range of Haemadipsa japonica, a sanguivorous land leech species endemic to Japan, by using nine polymorphic nuclear microsatellites (nSSR) and cytochrome oxidase subunit one (COI) sequences of mitochondrial DNA (mtDNA). Analyses using nSSR revealed that H. japonica exhibited a stronger regional genetic differentiation among populations (G'ST = 0.77) than other animal species, probably because of the low mobility of land leech. Analyses using mtDNA indicated that H. japonica exhibited two distinct lineages (A and B), which were estimated to have diverged in the middle Pleistocene and probably because of range fragmentation resulting from climatic change and glacial and interglacial cycles. Lineage A was widely distributed across Japan, and lineage B was found in southwestern Japan. Analyses using nSSR revealed that lineage A was roughly divided into two population groups (i.e., northeastern and southwestern Japan); these analyses also revealed a gradual decrease in genetic diversity with increasing latitude in lineage A and a strong genetic drift in populations of northeastern Japan. Combined with the largely unresolved shallow polytomies from the mtDNA phylogeny, these results implied that lineage A may have undergone a rapid northward migration, probably during the Holocene. Then, the regional genetic structure with local unique gene pools may have been formed within each lineage because of the low mobility of this leech species.
Lianas have a seasonal growth advantage over co‐occurring trees
Authors: Schnitzer Stefan A. , van der Heijden Geertje M. F.
Published: April 2019

The seasonal growth advantage hypothesis posits that plant species that grow well during seasonal drought will increase in abundance in forests with increasing seasonality of rainfall both in absolute numbers and also relative to co‐occurring plant species that grow poorly during seasonal drought. That is, seasonal drought will give some plant species a growth advantage that they lack in aseasonal forests, thus allowing them attain higher abundance. For tropical forest plants, the seasonal growth advantage hypothesis may explain the distribution of drought‐adapted species across large‐scale gradients of rainfall and seasonality. We tested the seasonal growth advantage hypothesis with lianas and trees in a seasonal tropical forest in central Panama. We measured the dry‐season and wet‐season diameter growth of 1,117 canopy trees and 648 canopy lianas from 2011 to 2016. We also evaluated how lianas and trees responded to the 2015–2016 El Niño, which was the third strongest el Niño drought on record in Panama. We found that liana growth rate was considerably higher during the dry‐season months than the wet‐season months in each of the five years. Lianas achieved one‐half of their annual growth during the 4‐month dry season. By contrast, trees grew far more during the wet season; they realized only one‐quarter of their annual growth during the dry season. During the strong 2015–2016 El Niño dry season, trees essentially stopped growing, whereas lianas grew unimpeded and as well as during any of the previous four dry seasons. Our findings support the hypothesis that seasonal growth gives lianas a decided growth advantage over trees in seasonal forests compared to aseasonal forests, and may explain why lianas peak in both absolute and relative abundance in highly seasonal tropical forests. Furthermore, the ability of lianas to grow during a strong el Niño drought suggests that lianas will benefit from the predicted increasing drought severity, whereas trees will suffer, and thus lianas are predicted to increase in relative abundance in seasonal tropical forests.
Ruthenium Aqua Complexes Supported by the Kläui Tripodal Ligand: Synthesis, Structure, and Application in Catalytic C–H Oxidation in Water
Authors: So Yat‐Ming , Wong Kang‐Long , Sung Herman H. Y. , Williams Ian D. , Leung Wa‐Hung
Published: April 2019

Water‐soluble ruthenium(III) aqua complexes supported by the Kläui tripodal ligand [Co(η5‐C5H5){P(O)(OEt)2}3]– (LOEt–) have been synthesized and structurally characterized, and their use as catalysts for C–H oxidation in water has been studied. The treatment of [Ru(LOEt)Cl2(MeCN)] with N‐donor ligands afforded the adducts [Ru(LOEt)Cl2(L)] (L = tBuNH2 (1), pyridine (2), imidazole (3)). Refluxing [Ru(LOEt)Cl2(MeCN)] in neat tBuNH2 gave the amidine complex [Ru(LOEt)Cl2{N(H)C(Me)NHtBu}] (4). Chloride abstraction of 1–3 with AgOTs (OTs = tosylate) in 1 M p‐toluenesulfonic acid afforded the water‐soluble RuIII diaqua complexes [Ru(LOEt)(H2O)2(L)](OTs)2 (L= tBuNH2 (5), pyridine (6), imidazole (7)), whereas that for 4 yielded the triaqua complex [Ru(LOEt)(H2O)3](OTs)2 (8). The crystal structures of 4, 5, 7, and 8 have been determined. The reduction of 5 with Zn dust in D2O gave a diamagnetic RuII species, whereas that in MeCN led to isolation of the RuII acetonitrile complex [RuII(LOEt)(MeCN)2(tBuNH2)](PF6) (9), which has been characterized by X‐ray diffraction. The RuIII aqua complexes proved to be moderately efficient catalysts for C–H bond oxidation with tert‐butyl hydroperoxide in water. For example, the oxidation of ethylbenzene with tert‐butyl hydroperoxide in water at room temperature in the presence of 0.1 mol‐% of 8 afforded acetophenone in ca. 62 % yield.
Poly(ethyleneimine)‐Mediated Consecutive Hydrogenation of Carbon Dioxide to Methanol with Ru Catalysts
Authors: Yoshimura Atsuki , Watari Ryo , Kuwata Shigeki , Kayaki Yoshihito
Published: April 2019

The utilization of polymeric amines for the hydrogenation of CO2 to methanol via formamides was explored with a focus on a catalytic promoter, as well as a beneficial reaction medium with enhanced basicity. Branched and linear poly(ethyleneimine)s (PEIs) were efficiently formylated in the presence of a series of PNHP‐pincer Ru complexes under CO2 hydrogenation conditions at 100 °C in THF. The obtained N‐formylated PEI was characterized by NMR spectroscopy. The formamide units on the polymer were reduced at a higher temperature under pressurized H2 to afford methanol and to recover the starting PEI. Moreover, PEI was optimally utilized for a one‐pot synthesis of methanol catalyzed by Ru–PNHP pincer complexes. The resulting polymer can be separated from the reaction mixture to afford methanol without the contamination of formic acid derivatives in the liquid phase. Under optimized reaction conditions of 2.0 MPa of CO2 and 6.0 MPa of H2 at 150 °C, methanol was successfully obtained with a turnover number (TON) up to 689, and the amine moiety can be used catalytically.
Convenient Assembly of Privileged (Hetero)Arene‐Fused Benzo[1.4]oxazepines via Two Tandem SNAr Events. Part 1 – On the Importance of the Intermittent Smiles Rearrangement
Authors: Sapegin Alexander , Krasavin Mikhail
Published: April 2019

New bis‐nucleophilic precursors to [1.4]oxazepines synthesized via SNAr‐Smiles rearrangement‐SNAr cascade have been designed. Employing them in base‐promoted condensation with aromatic bis‐electrophiles allowed differentiating between highly and poorly reactive substrates (i.e. those which can and cannot pass through the Smiles rearrangement barrier, respectively). The reactivity toward the desired course of cyclization can be restored by introducing electron‐withdrawing substituents in the bis‐electrophile precursor. This strongly argues for the importance of the Smiles rearrangement for the successful overall ring formation.
The links between entrance geometry, hypsometry and hydrodynamics in shallow tidally dominated basins
Authors: de Ruiter Peter J. , Mullarney Julia C. , Bryan Karin R. , Winter Christian
Published: April 2019

Geomorphological characteristics of tidal basins control hydrodynamics and sediment transport potential within such basins, for example, by adjusting the balance in tidal asymmetry. In this study we examine the effects of entrance geometry on tidal velocity asymmetry, slack water asymmetry, bed shear stress patterns and hypsometric profile shapes by comparison of six shallow meso‐tidal basins of Tauranga Harbour, New Zealand. Numerical model results show how tidal distortion increases with distance from a basin entrance. A simple ratio between basin width and entrance width defines levels of basin dilation. Sub‐basins with a constricted geometry and deep entrance channels are associated with small bed shear stress values and high rates of flood‐directed tidal velocity asymmetry in the sheltered basin centres, indicating a large potential for sediment deposition of larger particles. Moreover, slack water asymmetry within these basins is weakly ebb‐directed, indicating a small potential for transport of fine sediments out of the basins. The constricted depositional basins are characterized by convex hypsometric profiles with elevated intertidal regions. Unconstricted geometries are associated with larger bed shear stress values and more ebb‐directed tidal velocity asymmetry within basin centres, suggesting limited potential for overall sediment deposition. The slack tide duration asymmetry is weakly flood‐dominant indicating that limited input of fine sediment into the basins is possible. The comparatively high‐energy conditions within these exposed basins are associated with a less convex hypsometric intertidal profile. The ability to estimate tidal asymmetries is advantageous when developing management strategies related to ecosystem functioning, navigability or coastal protection in specific geomorphic settings. © 2019 John Wiley & Sons, Ltd.
Wnt/β‐catenin signaling induces the myomiRs miR‐133b and miR‐206 to suppress Pax7 and induce the myogenic differentiation program
Authors: Cui Shuang , Li Liang , Mubarokah Siti Nurul , Meech Robyn
Published: April 2019

The downregulation of Pax7 expression is an essential requirement for adult muscle progenitor cell differentiation during muscle regeneration. We previously found that canonical Wnt signals drive myogenic differentiation by positively regulating the expression of myogenic target genes, and also by negatively regulating Pax7 expression. To better understand how Wnt signals repress Pax7 expression, we screened for Wnt‐regulated microRNAs (miRNAs) that could target the Pax7 3′untranslated region (UTR). Using wild‐type and β‐catenin null primary mouse myoblasts, we identified several Wnt/β‐catenin regulated miRNAs, the most abundant of which were miR‐133b and miR‐206. While miR‐206 was previously identified as Pax7 regulator, miR‐133b has never been shown to regulate the Pax7 transcript. We show here that miR‐133b is a more potent inhibitor of Pax7 expression than miR‐206, and that it acts via a site adjacent to the miR‐206 binding site in the Pax7 3′UTR. The primary transcript encoding miR‐133b/miR‐206 is specifically induced by Wnt/β‐catenin, while the miR‐1/miR‐133a transcript is not; moreover, Wnt signals increase the secretion of mature miR‐133b/miR‐206 into exosomes. Overall, we conclude that miR‐133b and to a lesser degree miR‐206, but not miR‐1 or miR‐133a, are key components of the canonical Wnt‐mediated pathway that allows differentiation to proceed by relieving Pax7‐mediated repression of the myogenic program. Secretion of these miRNAs into exosomes may allow them to directly control the differentiation of neighboring cells.
circRNA and gastrointestinal cancer
Authors: Luo Bing , Tang Chao‐ming , Chen Jing‐Song
Published: April 2019

Circular RNAs (circRNAs) are a novel class of endogenous noncoding RNAs that form covalently closed continuous loops without 3′ end poly (A) tails and 5′ end caps. circRNAs are more conservative and stable than linear RNA. circRNAs can specifically bind to microRNAs as competing endogenous RNA, thereby directly or indirectly regulating the expression of related genes. circRNAs have been implicated in several cancers including gastrointestinal (GI) cancers. Some circRNAs have the potential to become biological biomarkers and therapeutic targets of GI cancers. However, the multiple functional roles of circRNAs in GI cancers remain largely unclear.
Heparan sulfate proteoglycans as trastuzumab targets in anoikis‐resistant endothelial cells
Authors: Onyeisi Jessica Oyie Sousa , Castanho de Almeida Pernambuco Filho Paulo , de Araujo Lopes Silvana , Nader Helena Bonciani , Lopes Carla Cristina
Published: April 2019

Anoikis is a form of programmed cell death induced by loss of contact from neighboring cells or from their extracellular matrix (ECM). Many tumorigenic cells are anoikis resistant, facilitating cancer progression and metastasis. Trastuzumab is a monoclonal antibody used for the treatment of breast and gastric cell cancer, but its mechanism of action is not well elucidated and its target molecules not well defined. Heparan sulfate proteoglycans (HSPGs) and glycosaminoglycans (GAGs) play important roles in tumor development and in response of cancer cells to drugs. This study investigates the effect of trastuzumab on the expression of HSPGs and sulfated glycosaminoglycans (SGAGs) in anoikis‐resistant endothelial cells. After trastuzumab treatment, endothelial cells resistant to anoikis show an increase in adhesion to fibronectin followed by a decrease in invasion, proliferation, and angiogenic capacity. In addition, a significant increase in the number of cells in the S phase of the cell cycle was also observed. In relation to HSPGs and SGAGs expression, we observed a decrease in syndecan‐4 and perlecan expression, as well as in the heparan sulfate biosynthesis in anoikis‐resistant endothelial cells after exposure to trastuzumab. Our results suggest that trastuzumab interacts with GAGs and proteoglycans of the cell surface and ECM and through this interaction controls cellular events in anoikis‐resistant endothelial cells.
Interleukin‐8 enhances myocilin expression, Akt‐FoxO3 signaling and myogenic differentiation in rat skeletal muscle cells
Authors: Milewska Marta , Domoradzki Tomasz , Majewska Alicja , Błaszczyk Maciej , Gajewska Małgorzata , Hulanicka Magdalena , Ciecierska Anna , Grzelkowska‐Kowalczyk Katarzyna
Published: April 2019

Interleukin (IL)‐8 is released both in visceral adipose tissue and in contracting skeletal muscles. In this study, we examined cellular pathways associated with muscle hypertrophy, chosen on the basis of microRNA profiling, in differentiating rat primary skeletal muscle cells (RSkMC) treated with IL‐8 (1 ng/ml) for 11 days. IL‐8 increased myocilin expression, Akt phosphorylation, FoxO3 dispersion throughout the cytoplasm, and reduced FoxO3 level. IL‐8 decreased the expression of atrogin and MuRF1 and increased myotube length and diameter. We concluded that IL‐8 present in extracellular environment of myoblasts induced to differentiation stimulates expression of myocilin, a protein important for skeletal muscle hypertrophy. This phenomenon was associated with: (a) activation of myogenic transcription, (b) increased phosphorylation and activation of PKB/Akt, leading to (c) cytoplasm distribution and degradation of a transcription factor FoxO3, (d) decreased expression of gene markers of proteolysis, atrogin and Murf1, and (e) increased myotube length and diameter. In this regard, IL‐8 affects skeletal muscle cells similarly to IGF‐I and can be considered as a potent anticatabolic factor for skeletal muscle.
Fabrication of 3D calcium‐alginate scaffolds for human glioblastoma modeling and anticancer drug response evaluation
Authors: Chaicharoenaudomrung Nipha , Kunhorm Phongsakorn , Promjantuek Wilasinee , Heebkaew Nudjanad , Rujanapun Narawadee , Noisa Parinya
Published: April 2019

The three‐dimensional (3D) cell culture model has been increasingly used to study cancer biology and screen for anticancer agents due to its close mimicry to in vivo tumor biopsies. In this study, 3D calcium(Ca)‐alginate scaffolds were developed for human glioblastoma cell culture and an investigation of the responses to two anticancer agents, doxorubicin and cordycepin. Compared to the 2D monolayer culture, glioblastoma cells cultured on these 3D Ca‐alginate scaffolds showed reduced cell proliferation, increased tumor spheroid formation, enhanced expression of cancer stem cell genes (CD133, SOX2, Nestin, and Musashi‐1), and improved expression of differentiation potential‐associated genes (GFAP and β‐tubulin III). Additionally, the vascularization potential of the 3D glioblastoma cells was increased, as indicated by a higher expression of tumor angiogenesis biomarker (VEGF) than in the cells in 2D culture. To highlight the application of Ca‐alginate scaffolds, the 3D glioblastomas were treated with anticancer agents, including doxorubicin and cordycepin. The results demonstrated that the 3D glioblastomas presented a greater resistance to the tested anticancer agents than that of the cells in 2D culture. In summary, the 3D Ca‐alginate scaffolds for glioblastoma cells that were developed in this study offer a promising platform for anticancer agent screening and the discovery of drug‐resistant mechanisms of cancer.
Comparative morphological examination of vertebral bodies of teleost fish using high‐resolution micro‐CT scans
Authors: Sakashita Misaki , Sato Mao , Kondo Shigeru
Published: April 2019

Vertebral bodies of teleost fish are formed by the sclerotomal bone covering the chordacentrum. The internal part of the sclerotomal bone is composed of an amphicoelous hourglass shaped autocentrum, which is common in most fish species. In contrast, the external shape of the sclerotomal bone varies extensively among species. There are multiple hypotheses regarding the composition and formation of the external structure. However, as they are based on studies of few extant or extinct species, their applicability to other species remains to be clarified. To understand the morphology, formation, and composition of vertebral bodies in teleosts, we performed a comparative analysis using micro‐CT scans of 32 species from 10 orders of Teleostei and investigated the detailed morphology of the sclerotomal bone, especially its plate‐like ridge and trabeculae. We discovered two structural characteristics that are shared among most of the examined species. One was the sheet‐like trabeculae that extend radially from the center of the vertebral body with a constant thickness. The other was the presence of hollow spaces on the internal parts of the lateral ridge and trabeculae. The combination of different arrangements of sheet‐like trabeculae and internal hollow spaces formed different shapes of the lateral structure of the vertebral body. The properties of these two characteristics suggest that the external part of the sclerotomal bone grows outward by deposition at the bone tip, and that, concurrently, bone absorption occurs in the internal part of the sclerotomal bone. The vertebral arches were also formed by the sheet‐like trabeculae, indicating that both, the vertebral body and the arches, are formed by the same component. The micro‐CT scanning data were uploaded to a public database so they can be used for future studies on fish vertebrae.
Genetic variations in death receptor domain 4 gene and the susceptibility to hepatitis C related hepatocellular carcinoma
Authors: Zayed Shahira Amin , Zahran Nariman M. , Khorshied Mervat Mamdooh , Abdel‐Aziz Ashraf Omar , Mahmoud Ola , Morsy Shereif Ahmed , Shousha Hend Ibrahim , Elbaz Tamer Mahmoud , Nabeel Mohamed Mahmoud , Harb Amira Ramadan Korany
Published: April 2019

Background

Hepatocellular carcinoma (HCC) is a leading cause of cancer mortality worldwide, particularly in Egypt. The role of apoptosis in tumorigenesis has been well‐documented and resistance to apoptosis is a hallmark of cancer. Several studies discussed the association between death receptor 4 (DR4) genetic variants and HCC risk.

Aim

To study the possible link between DR4 gene polymorphisms and the susceptibility to HCC.

Methods

Genotyping of DR4‐C626G, ‐A683C, and DR4‐A1322G single nucleotide polymorphisms (SNP) was determined by polymerase chain reaction assay for 100 de novo HCV‐related HCC patients, 100 chronic hepatitis C‐related liver cirrhosis patients, and 150 healthy controls.

Results

DR4‐A1322G polymorphic genotypes (AG and GG) were significantly higher in HCC and cirrhotic patients than controls. The AG genotype conferred two‐fold increased risk of HCC (odds ratio [OR], 2.34; 95% confidence interval [CI], 1.56‐3.51) and the risk increased to three‐fold for the GG genotype (OR, 3.51; 95%CI, 2.33‐5.28). The frequency of DR4‐C626G and ‐A683C SNPs in HCC and cirrhotic patients were not significantly different from the controls. Combined genotype analysis showed that coinheritance of the polymorphic genotypes of DR4‐C626G and ‐A1322G conferred nine‐fold increased risk of HCC (OR, 9.34; 95%CI, 3.76‐23.12). The risk increased to be 12‐fold when DR4‐A683C and ‐A1322G variants were coinherited (OR, 11.9; 95%CI, 4.82‐29.39). Coexistence of the variant genotypes of the three SNPs conferred almost 10‐fold increased risk of HCC (OR, 9.75; 95%CI, 1.86‐51.19).

Conclusions

The G allele of DR4 ‐A1322G could be considered as a novel independent molecular predictor for HCV‐related HCC in the Egyptian population.
Differentiation Between Malignant and Benign Lymph Nodes: Role of Superb Microvascular Imaging in the Evaluation of Cervical Lymph Nodes
Authors: Sim Joo Kyung , Lee Ji Ye , Hong Hyun Sook
Published: April 2019

Objectives

This study aimed to assess the value of Superb Microvascular Imaging (SMI; Canon Medical Systems, Otawara, Japan) for distinguishing between benign and malignant cervical lymph nodes (LNs) and to compare SMI with power Doppler ultrasound (PDUS).

Methods

Power Doppler ultrasound and SMI examinations were performed for patients’ cervical LNs. The distribution of feeding vessels, number, and appearance of internal vessels were analyzed by 2 readers, and the results of PDUS and SMI were compared. Interobserver agreement was assessed. A subgroup analysis was performed to assess differences in vascular patterns between metastasis and tuberculous lymphadenitis and between Kikuchi disease and lymphoma. The diagnostic performance for distinguishing between benign and malignant LNs was calculated.

Results

In total, 147 patients with 147 cervical LNs (85 benign and 62 malignant) were assessed. Interobserver agreement was moderate to strong for SMI. There were significant differences in the vascular patterns between benign and malignant LNs on SMI (distribution, number, and appearance, all P < .001), but not on PDUS. In the subgroup analysis, SMI showed a significant difference in the vascular patterns observed between metastasis and tuberculous lymphadenitis (distribution, P = .012; number, P = .014; and appearance, P = .005). Superb Microvascular Imaging detected significantly greater numbers of vessels in lymphoma than in Kikuchi disease (P = .012). The sensitivity of SMI was significantly greater than that of PDUS in distinguishing malignant from benign LNs (86.9% versus 54.1%; P < .001).

Conclusions

Superb Microvascular Imaging yields more detailed information about nodal vessels than does PDUS by enabling visualization of small nodal vessels. Superb Microvascular Imaging is useful and feasible for differentiating between malignant and benign cervical LNs.
Kinetic study on enantioselective resolution of (R,S)‐2‐phenylpropionic acid through Novozyme 435–catalyzed esterification
Authors: Yuan Xin , Zhang Panliang , Xu Weifeng , Tang Kewen
Published: April 2019

2‐Phenylpropionic acid (2‐PPA) is a very important chiral intermediate in the synthesis of aryl propionic acid drugs with anti‐inflammatory and analgesic effects. Enzymatic kinetic resolution of (R,S)‐2‐PPA using n‐hexanol as an acyl donor was carried out in n‐hexane. Lipases from different sources were used to catalyze the esterification of 2‐PPA, among which Novozyme 435 had the highest catalytic efficiency. The effects of reaction conditions on conversion (c) and enantiomeric excess (ee), involving temperature, substrate concentrations, enzyme loading, and reaction time were investigated. The kinetic model based on the Ping‐Pong bi‐bi mechanism was established to simulate the enzymatic esterification process. The experimental values of initial rates of various 2‐PPA concentrations were consistent with the simulated values.
Modeling of Glass Transition Temperatures for Polymeric Coating Materials: Application of QSPR Mixture‐based Approach
Authors: Petrosyan Lyudvig S. , Sizochenko Natalia , Leszczynski Jerzy , Rasulev Bakhtiyor
Published: April 2019

Cross‐linked block copolymers are structurally complex, and utilization of traditional methods of molecular representation in chemoinformatics is only of limited applicability. Therefore, we introduced new techniques of structural representation for block copolymers. We developed additive and combinatorial approaches that treat a copolymer as a mixture system. In this approach, DRAGON descriptors are concentration‐weighted for all chemicals in the reaction mixture. As a proof of concept, we have studied glass transition temperatures of block copolymers of hydroxyalkyl‐ and dihydroxyalkyl carbamate terminated poly(dimethylsiloxane) oligomers with poly(‐caprolactone) and developed four quantitative structure‐property relationships (QSPR) models. The correlation coefficient (R2) for mentioned QSPR models ranges from 0.851 to 0.911 for the training set. In addition to the newly introduced technique we found that the octanol−water partition coefficient and 3D‐MoRSE unweighted descriptors were the most important descriptors for the studied property. The results of the study demonstrated that all chemicals in reaction mixture influenced the glass transition temperatures.
The Role of Intramolecular Interactions on the Bioactive Conformation of Epinephrine
Authors: Silva Daniela R. , Silla Josué M. , Santos Lucas A. , da Cunha Elaine F. F. , Freitas Matheus P.
Published: April 2019

The structure of bioactive compounds inside their biological target is mainly dictated by the intermolecular interactions present in the binding side, whereas intramolecular interactions are responsible for the structure of an isolated molecule. Accordingly, this work reports the relative significance of these interactions for the bioactive conformation of the N‐protonated epinephrine. The crystallized structure of epinephrine has a gauche orientation of the O−C−C−N torsion angle. Conformational analysis in the gas phase and implicit water was performed to investigate the main intramolecular forces favoring this conformational preference, which was primarily attributed to the electrostatic interaction between hydroxyl and ammonium groups. However, when the conformers were docked into the active site, intramolecular interactions were surpassed by intermolecular hydrogen bonds with neighboring amino acid residues. Nonetheless, structural modifications aiming at strengthening intramolecular interactions could be used to modulate a bioactive conformation, thereby assisting in the structure‐based design of new chemical entities.
Commensurate Nb2Zr5O15: Accessible Within the Field Nb2ZrxO2x+5 After All
Authors: Wiedemann Dennis , Orthmann Steven , Mühlbauer Martin J. , Lerch Martin
Published: April 2019

Doped niobium zirconium oxides are applied in field‐effect transistors and as special‐purpose coatings. Whereas their material properties are sufficiently known, their crystal structures remain widely uncharacterized. Herein, we report on the comparably mild sol‐gel synthesis of Nb2Zr5O15 and the elucidation of its commensurately modulated structure via neutron diffraction. We describe the structure using the most appropriate superspace as well as the convenient supercell approach. It is part of an α‐PbO2‐homeotypic field with the formula Nb2ZrxO2x+5, which has previously been reported only for x≥5.1, and is closely related to the structure of Hf3Ta2O11. The results, supported by X‐ray diffraction and additional synthesis experiments, are contextualized within the existing literature. Via the sol‐gel route, metastable Nb−Zr−O compounds and their heavier congeners are accessible that shed light on possible structures of these commercially utilized materials.
Inflammation‐dependent overexpression of c‐Myc enhances CRL4DCAF4 E3 ligase activity and promotes ubiquitination of ST7 in colitis‐associated cancer
Authors: Liu Hong , Lu Wenzhu , He Hongbo , Wu Jin , Zhang Caiguo , Gong Hanlin , Yang Chunmei
Published: April 2019

Inflammation is well known as an important driver of the initiation of colitis‐associated cancer (CAC). Some cytokines, such as IL‐6 and TNF‐α can activate expression of the oncogene c‐Myc (MYC) and regulate its downstream effects. Cullin‐RING E3 Ligases (CRLs) are emerging as master regulators controlling tumorigenesis. Here, we demonstrate that two cullin genes, CUL4A and CUL4B, but not other members, are specifically overexpressed in CAC tumour samples and positively correlate with levels of the proinflammatory cytokines IL‐1β and IL‐6. In vitro experiments revealed that the transcription factor c‐Myc can specifically activate the expression of CUL4A and CUL4B by binding to a conserved site (CACGTG) located in their promoters. Additionally, we found that both CUL4A and CUL4B can form an E3 complex with DNA damage‐binding protein 1 (DDB1) and DDB1‐CUL4‐associated factor 4 (DCAF4). In vitro and in vivo ubiquitination analyses indicate that CRL4DCAF4 E3 ligase specifically directs degradation of ST7 (suppression of tumorigenicity 7). Overexpression of c‐Myc in human colon epithelial cells resulted in the accumulation of CUL4A, CUL4B and DCAF4, but degradation of ST7. In contrast, knockdown of c‐Myc, CUL4A or CUL4B in the colon adenocarcinoma cell line HT29 caused accumulation of ST7 and inhibition of cell proliferation, colony formation ability and in vivo tumour growth. Collectively, our results provide in vitro and in vivo evidence that c‐Myc regulates CRL4DCAF4 E3 ligase activity to mediate ubiquitination of ST7, whose presence is physiologically essential for CAC tumorigenesis. © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Cover Image, Volume 68, Issue 5
Authors: Aguero Angel , Quiles‐Carrillo Luis , Jorda‐Vilaplana Amparo , Fenollar Octavio , Montanes Nestor
Published: April 2019

The cover image is based on the Research Article Effect of different compatibilizers on environmentally friendly composites from poly(lactic acid) and diatomaceous earth by Angel Aguero et al. DOI: 10.1002/pi.5779.

image
Urban environment and mortality differentials in Spain
Authors: Voigt Mathias , Ordanovich Dariya , Viciana Fernández Francisco , Cilek Laura Ann , Canovas Balboá Rosa , Ramiro Fariñas Diego
Published: April 2019

Analyses of health and mortality disparities between today's urban and rural populations appear to be exclusively focused on vastly urbanising countries. By incorporating environmental data at census tract level and accounting for within‐area homogeneity, this work attempts to extend classic rural–urban comparisons. Geographical information is linked to a register‐based mortality follow up and Spanish census data for the autonomous community of Andalusia. We then apply mixed effects Cox proportional hazards models to estimate individual mortality differences and account for area variations between residential areas. Estimated effects suggest that the shared degree of “urbanicity” does not affect individual hazards of mortality, whereas environmental‐ and population‐based measures influence the relative risk of dying despite controlling for individual‐level risk factors. Although we do not find an impact of physical urban measures, our results reveal persistent that area‐related mortality disparities which can help to explain the mechanisms behind prevalent spatial‐temporal inequalities such as those in Andalusia.
Application of Silver Antibacterial and Antifungal Nanolayers for Ocular Prostheses Coating
Authors: Koev Krassimir , Donkov Nikolai , Stankova Nadya , Moraliiski Emil , Najdenski Hristo , Nurgaliev Timerfayaz , Zaharieva Maya , Avramov Latchezar
Published: April 2019

The paper reports on antibacterial and antifungal properties of Ag‐doped Al2O3 nanolayers deposited by RF reactive magnetron sputtering on glass ocular prostheses. The study is provoked by the need of suppressing the infections caused by pathogenic microorganisms following the placement of ocular prostheses. This brings about the idea of forming protective coatings with antibacterial and antifungal properties on the prostheses. The surface elemental composition and the morphological characteristics of the coatings are investigated by XPS and SEM measurements. Further, the microbiological studies are conducted to establish the antibacterial and antifungal action of the nanocomposite Ag/Al2O3 layers against Gram‐positive and ‐negative bacteria, and Candida albicans. The strongest action of the layers is found against Pseudomonas aeruginosa − full inactivation after 2 h; Escherichia coli and Candida albicans – full inactivation after 5 h; Staphylococcus aureus − full inactivation after 24 h. The experimental findings suggest a very promising application of such antibacterial and antifungal Ag/Al2O3 nanolayers regarding the reduction of eye infections when implanting ocular prostheses.
Analysis of factors impacting wind and solar sectors—Challenges to sustainable development (Four Country Study)
Authors: Thapar Sapan , Sharma Seema , Verma Ashu
Published: April 2019

Deployment of renewable energy has progressed remarkably, with 1,000 GW installations (end of 2017), comprising 540 GW wind and 400 GW solar photovoltaic assets. However, the growth has been nonhomogenous, with spatial and temporal variations witnessed even within countries. Existing literature is focused on policy‐related factors, ignoring nonpolicy variables. We conducted a panel data regression to identify nonpolicy variables impacting wind and solar power sectors in four countries—Germany, India, Japan, and the United States; these rank among top five globally in terms of renewable deployment. Impact assessment of nine variables on wind (period 2004–2016) and 10 variables on solar (period 2006–2016) was undertaken for this study. Long‐term energy data trends highlighted continuous use of oil, amid a growing share of gas and renewable power, along with a diminishing role of nuclear and coal power. Regression analysis reflected significance of commercial factors such as module cost and renewable country index, impacting the growth of these two sectors. Energy imports came out as a strong driver for wind as the sector was initially promoted for enhancing energy security. Contribution of fossil fuels in energy supply also displayed a high significance. Greenhouse gases emissions did not come strongly due to continued dominance of fossil fuels, carbon emissions from ‘nonelectricity’ use, and reduction in use of nuclear power. Suggestions for a steady growth include facilitating business transformation of utilities, enhancing ease of doing business, and developing new markets such as electric mobility and heating.
Twinned Tungsten Carbonitride Nanocrystals Boost Hydrogen Evolution Activity and Stability
Authors: Kou Zongkui , Wang Tingting , Wu Haijun , Zheng Lirong , Mu Shichun , Pan Zhenghui , Lyu Zhiyang , Zang Wenjie , Pennycook Stephen J. , Wang John
Published: April 2019

Synergistic integration of two active metal‐based compounds can lead to much higher electrocatalytic activity than either of the two individually, due to the interfacial effects. Herein, a proof‐of‐concept strategy is creatively developed for the successful fabrication of twinned tungsten carbonitride (WCN) nanocrystals, where W2C and WN are chemically bonded at the molecule level. High‐angle annular dark‐field scanning transmission electron microscopy (HAADF‐STEM) and X‐ray absorption fine structure (XAFS) spectroscopy analyses demonstrate that the intergrowth of W2C and WN in the WCN nanocrystals produces abundant N–W–C interfaces, leading to a significant enhancement in catalytic activity and stability for hydrogen evolution reaction (HER). Indeed, it shows 14.2 times higher and 140 mV lower in the respective turn‐over frequency (TOF) and overpotential at 10 mA cm−2 compared to W2C alone. To complement the experimental observation, the theoretical calculations demonstrate that the WCN endows more favorable hydrogen evolution reaction than the single W2C or WN crystals due to abundant interfaces, beneficial electronic states, lower work function, and more active W sites at the N–W–C interfaces.
How Do Local Labor Markets and Human Capital Affect Employment Outcomes after Job Loss?
Authors: Ueda Ken
Published: April 2019

This article uses the Longitudinal Employer‐Household Dynamics to evaluate how local industry concentration affects earnings losses for displaced workers. “Concentrated industries” are those industries with a high employment share within a labor market. This article compares earnings changes between displaced workers and job stayers within concentrated industries to the same within less concentrated industries. A separate comparison is made based on the expected level of job availability within the labor market. The findings show that earnings changes for displaced workers relative to job stayers are 7–13% higher within concentrated industries when job loss occurs during periods of high job availability. Earnings changes are 4.5–6% lower, however, when the same comparison is made during periods of low job availability. When firms are hiring workers, they are more likely to hire those previously employed within the same industry, since these workers have accumulated more relevant human capital.
Converting tests of fundamental social, cognitive, and affective processes into clinically useful bio‐behavioral markers for neurodevelopmental conditions
Authors: Loth Eva , Evans David W.
Published: April 2019

Biomarker discovery has become a central topic in neurodevelopmental research. A validated biomarker could be any objective measure or test that has clinical utility for diagnostic, stratification, or predictive purposes, or that can be used to objectively measure therapeutic efficacy. Here we discuss the potential and challenges of converting tests of fundamental social, cognitive, emotional and motivational processes into clinically useful bio‐behavioral markers for neurodevelopmental conditions. Given the broad clinical and etiological heterogeneity of many neurodevelopmental conditions, we propose moving the focus from identifying group‐defining characteristics to creating cross‐domain bio‐behavioral profiles at the individual level. We outline steps to develop tests that reflect the relevant domains and that are comparable, engaging and sensitive across large age and ability ranges. Analytical validation of these tests requires creating age norms, and optimizing psychometric properties. Individual bio‐behavioral fingerprints of strengths and difficulties across domains can then be combined with multivariate approaches to identify “subgroups.” This may help researchers and clinicians to compare individuals with and without intellectual disability, track developmental stability versus changes, and facilitate family genetic studies. Clinical validation requires including these tests in multidisciplinary, longitudinal and/ or intervention studies to ascertain whether particular subgroups differ in terms of their etiology, clinical symptom profile, prognosis or therapeutic benefit. Potential advantages of bio‐behavioral tests over other biomarker methodologies, such as neuroimaging measures, include the low cost, ease of administration and analysis, low risk, and scalability through on‐line assessments or tablet applications.

This article is categorized under:

Neuroscience > Development

Psychology > Theory and Methods

Neuroscience > Clinical Neuroscience

Neuroscience > Cognition
Genus two modular bootstrap
Authors: Cho Minjae , Collier Scott , Yin Xi
Published: April 2019

Abstract

We study the Virasoro conformal block decomposition of the genus two partition function of a two-dimensional CFT by expanding around a ℤ3-invariant Riemann surface that is a three-fold cover of the Riemann sphere branched at four points, and explore constraints from genus two modular invariance and unitarity. In particular, we find “critical surfaces” that constrain the structure constants of a CFT beyond what is accessible via the crossing equation on the sphere.
Bootstrap and collider physics of parity violating conformal field theories in d = 3
Authors: Chowdhury Subham Dutta , David Justin R. , Prakash Shiroman
Published: April 2019

Abstract

We study the crossing equations in d = 3 for the four point function of two U(1) currents and two scalars including the presence of a parity violating term for the s-channel stress tensor exchange. We show the existence of a new tower of double trace operators in the t-channel whose presence is necessary for the crossing equation to be satisfied and determine the corresponding large spin parity violating OPE coefficients. Contrary to the parity even situation, we find that the parity odd s-channel light cone stress tensor block do not have logarithmic singularities. This implies that the parity odd term does not contribute to anomalous dimensions in the crossed channel at this order light cone expansion. We then study the constraints imposed by reflection positivity and crossing symmetry on such a four point function. We reproduce the previously known parity odd collider bounds through this analysis. The contribution of the parity violating term in the collider bound results from a square root branch cut present in the light cone block as opposed to a logarithmic cut in the parity even case, together with the application of the Cauchy-Schwarz inequality.
The role of leptons in electroweak baryogenesis
Authors: de Vries Jordy , Postma Marieke , van de Vis Jorinde
Published: April 2019

Abstract

We investigate the role of leptons in electroweak baryogenesis by studying a relatively simple framework inspired by effective field theory that satisfies all Sakharov conditions. In particular, we study the effectiveness of CP-violating source terms induced by dimension-six Yukawa interactions for quarks and charged leptons. Despite the relatively small Yukawa coupling, CP-violating source terms involving taus are quite effective and can account for the observed matter-antimatter asymmetry. We obtain analytical and numerical expressions for the total baryon asymmetry, the former providing important insight into what makes lepton CP violation relatively effective compared to quark CP violation. Leptons also play an important role if the CP-violating source involves top quarks. While the tau Yukawa coupling in the Standard Model is small, it significantly enhances the baryon asymmetry by transferring the chiral asymmetry in quarks, which is washed out by strong sphalerons, to a chiral asymmetry in leptons. We conclude that leptons should not be ignored even if CP violation is limited to the quark sector. The role of leptons can be further increased in scenarios of new physics with additional chiral-symmetry-breaking interactions between quarks and leptons, as can happen in models with additional Higgs bosons or leptoquarks. Finally, we study CP-violating dimension-six Yukawa interactions for lighter quarks and leptons but conclude that these lead to too small baryon asymmetries.
The most irrational rational theories
Authors: Benjamin Nathan , Dyer Ethan , Fitzpatrick A. Liam , Xin Yuan
Published: April 2019

Abstract

We propose a two-parameter family of modular invariant partition functions of two-dimensional conformal field theories (CFTs) holographically dual to pure three-dimensional gravity in anti de Sitter space. Our two parameters control the central charge, and the representation of SL(2, ℤ). At large central charge, the partition function has a gap to the first nontrivial primary state of

$$ \frac{c}{24} $$

c
24

. As the SL(2, ℤ) representation dimension gets large, the partition function exhibits some of the qualitative features of an irrational CFT. This, for instance, is captured in the behavior of the spectral form factor. As part of these analyses, we find similar behavior in the minimal model spectral form factor as c approaches 1.
Electroweak baryogenesis above the electroweak scale
Authors: Glioti Alfredo , Rattazzi Riccardo , Vecchi Luca
Published: April 2019

Abstract

Conventional scenarios of electroweak (EW) baryogenesis are strongly constrained by experimental searches for CP violation beyond the SM. We propose an alternative scenario where the EW phase transition and baryogenesis occur at temperatures of the order of a new physics threshold Λ far above the Fermi scale, say, in the 100–1000 TeV range. This way the needed new sources of CP-violation, together with possible associated flavor-violating effects, decouple from low energy observables. The key ingredient is a new CP- and flavor-conserving sector at the Fermi scale that ensures the EW symmetry remains broken and sphalerons suppressed at all temperatures below Λ.

We analyze a minimal incarnation based on a linear O(N) model. We identify a specific large-N limit where the effects of the new sector are vanishingly small at zero temperature while being significant at finite temperature. This crucially helps the construction of realistic models. A number of accidental factors, ultimately related to the size of the relevant SM couplings, force N to be above ∼ 100. Such a large N may seem bizarre, but it does not affect the simplicity of the model and in fact it allows us to carry out a consistent re-summation of the leading contributions to the thermal effective potential. Extensions of the SM Higgs sector can be compatible with smaller values N ∼ 20–30.

Collider signatures are all parametrically suppressed by inverse powers of N and may be challenging to probe, but present constraints from direct dark matter searches cannot be accommodated in the minimal model. We discuss various extensions that satisfy all current bounds. One of these involves a new gauge force confining at scales between ∼ 1 GeV and the weak scale.
Correction to: Microdialysis in Postoperative Monitoring of Gastrointestinal Organ Viability: A Systematic Review
Authors: Sabroe Jonas Emil , Qvist Niels , Ellebæk Mark Bremholm
Published: April 2019

In the original article, most of the reference numbers in the first column in Table 1 are off by one reference. Following is the corrected table.