bluuebunny/crossref_metadata_2025 huggingface dataset:
Viruses as key modulators of the TGF‐β pathway; a double‐edged sword involved in cancer
Authors: Mirzaei Habibollah , Faghihloo Ebrahim
Published: January 2018

Transforming growth factor‐β (TGF‐β) signaling pathway is a key network in cell signaling that controls vital processes such as proliferation, differentiation, apoptosis, epithelial‐mesenchymal transition, and migration, thus acting as a double‐edged sword in normal development and diseases, in particular organ fibrosis, vascular disorders, and cancer. Early in tumorigenesis, the pathway exerts anti‐tumor effects through suppressing cell cycle and inducing apoptosis, while during late stages, it functions as a tumor promoter by enhancing tumor invasiveness and metastasis. This signaling pathway can be perturbed by environmental and genetic factors such as microbial interference and mutation, respectively. In this way, the present review describes the modulation of the TGF‐β pathway by oncogenic human viral pathogens and other viruses. The main mechanisms by which viruses interferes with TGF‐β signaling seems to be through (1) the alteration of either TGF‐β protein expression or activation, (2) the modulation of the TGF‐β receptors or SMADs factors (by interfering with their levels and functions), (3) the alteration of none‐SMAD pathways, and (4) indirect interaction with the pathway by the modulation of transcriptional co‐activator/repressor and regulators of the pathway. Given the axial role of this pathway in tumorigenesis, it can be regarded as an attractive target for cancer therapy. Hence, further investigations on this subject may represent molecular targets among either TGF‐β signaling molecules or viral factors for the treatment and management of viral infection consequences such as cancer.
Naringenin (4,5,7‐trihydroxyflavanone) suppresses the development of precancerous lesions via controlling hyperproliferation and inflammation in the colon of Wistar rats
Authors: Rehman Muneeb U. , Rahman Mir Manzoor Ur , Farooq Adil , Rashid Shahzada Mudasir , Ahmad Bilal , Bilal Ahmad Sheikh , Ali Rayeesa , Hussain Ishraq , Masoodi Mubashir , Muzamil Showkeen , Madkhali Hassan , Ahmad Ganaie Majid
Published: January 2018

Colon cancer is a world‐wide health problem and one of the most dangerous type of cancer, affecting both men and women. Naringenin (4, 5, 7‐trihydroxyflavanone) is one of the major flavone glycoside present in citrus fruits. Naringenin has long been used in Chinese's traditional medicine because of its exceptional pharmacological properties and non‐toxic nature. In the present study, we investigated the chemopreventive potential of Naringenin against 1,2‐dimethyhydrazine (DMH)‐induced precancerous lesions, that is, aberrant crypt foci (ACF) and mucin depleted foci (MDF), and its role in regulating the oxidative stress, inflammation and hyperproliferation, in the colon of Wistar rats. Animals were divided into five groups. In groups 3‐5, Naringenin was administered at the dose of 50 mg/kg b. wt. orally while in groups 2‐4, DMH was administered subcutaneously in the groin at the dose of 20 mg/kg b. wt. once a week for first 5 weeks and animals were euthanized after 10 weeks. Administration of Naringenin ameliorated the development of DMH‐induced lipid peroxidation, ROS formation, precancerous lesions (ACF and MDF) and it also reduced the infiltration of mast cells, suppressed the immunostaining of NF‐κB‐p65, COX‐2, i‐NOS PCNA and Ki 67 Naringenin treatment significantly attenuated the level of TNF‐α and it also prevented the depletion of the mucous layer. Our findings suggest that Naringenin has strong chemopreventive potential against DMH‐induced colon carcinogenesis but further studies are warranted to elucidate the precise mechanism of action of Naringenin.
Cantharidic acid induces apoptosis of human leukemic HL‐60 cells via c‐Jun N‐terminal kinase‐regulated caspase‐8/‐9/‐3 activation pathway
Authors: Wang Shih‐Chung , Chow Jyh‐Ming , Chien Ming‐Hsien , Lin Chiao‐Wen , Chen Hui‐Yu , Hsiao Pei‐Ching , Yang Shun‐Fa
Published: January 2018

Cantharidin, a natural toxin from blister beetles, has shown potent anticancer activities on many solid tumor cells. Recently, cantharidin and its analogue, norcantharidin, were also shown to suppress nonsolid tumors such as chronic myeloid leukemia, acute myeloid leukemia (AML), and leukemic stem cells. However, there is no available information to address the effects of cantharidic acid (CAC), a hydrolysis product of cantharidin, on human AML cells. The present study showed that CAC, at a range of concentrations (0‐20 μM), concentration‐dependently inhibited cell proliferation in the HL‐60 AML cell line. Western blot and flow cytometric assays demonstrated that CAC induced several features of apoptosis such as sub G1‐phase cell increase, phosphatidylserine (PS) externalization, and significantly activated proapoptotic signaling including caspase‐8, −9, and −3 activation and poly(ADP‐ribose) polymerase (PARP) cleavage in HL‐60 AML cells. Moreover, treatment of HL‐60 cells with CAC induced concentration‐ and time‐ dependent activation of p38 mitogen‐activated protein kinase (p38 MAPK) and c‐Jun N‐terminal kinase (JNK). Only JNK‐, but not p38 MAPK‐specific inhibitor can reverse the CAC‐induced activation of the caspase‐8, −9, and −3. We concluded that CAC can induce apoptosis in human leukemic HL‐60 cells via a caspases‐dependent pathway, and that the apoptosis‐inducing effect of CAC can be regulated by JNK activation signaling.
Copyright for the digital age — A call for legislative reversibility
Authors: Oberholzer-Gee Felix
Published: January 2018

Policymakers tend to adopt too narrow a view of the creative industries when determining the desirability of copyright protection. In these industries, authors will often create new works despite weak protection. As recent developments in the music industry illustrate, markets for complements alone can be sufficiently lucrative to entice artists to remain active even when copyright is seriously weakened. However, the value of complements is difficult to forecast. As a result, lawmakers will often set inappropriate copyright terms. In this note, I call for an approach to copyright legislation that makes it feasible to correct these unavoidable mistakes.
The ‘new firm paradigm’ and the provision of training: The impact of ICT, workplace organization and human capital
Authors: Hollenstein Heinz , Stucki Tobias
Published: January 2018

The paper analyzes the relevance of the three constituent elements of the ‘new firm paradigm’, i.e. ICT, workplace organization and human capital, as determinants of a firm’s provision of training. We concentrate on apprenticeship training, which in German-speaking countries is a widespread practice of skill formation. Econometric studies dealing with a firm’s provision of apprenticeships so far did not pay much attention to the influence of a shift towards the new paradigm. We find that apprenticeship training is an appropriate way of skill formation in advanced economies, but this may not be the case in leading-edge segments of the economy.
Equilibrium stability for non-uniformly hyperbolic systems
Authors: ALVES JOSÉ F. , RAMOS VANESSA , SIQUEIRA JAQUELINE
Published: January 2018

We prove that for a wide family of non-uniformly hyperbolic maps and hyperbolic potentials we have equilibrium stability, i.e. the equilibrium states depend continuously on the dynamics and the potential. For this we deduce that the topological pressure is continuous as a function of the dynamics and the potential. We also prove the existence of finitely many ergodic equilibrium states for non-uniformly hyperbolic skew products and hyperbolic Hölder continuous potentials. Finally, we show that these equilibrium states vary continuously in the $\text{weak}^{\ast }$ topology within such systems.
FOUR PRECERAMIC POINTS NEWLY DISCOVERED IN BELIZE: A COMMENT ON STEMP ET AL. (2016:279–299) – CORRIGENDUM
Authors: Stemp W. James , Awe Jaime J. , Brown M. Kathryn , Harrison-Buck Eleanor , Helmke Christophe G. B. , Wrobel Gabriel D. , Yaeger Jason
Published: January 2018

In the original publication of this article, the title was printed as “Four Preceramic Points Newly Discovered in Belize: A Comment on Stemp et al. (1996:279–299).” The article has been updated to the correct title. The authors apologize for this error.
Punctuated changes in the morphology of an endemic diatom from Lake Titicaca
Authors: Spanbauer Trisha L. , Fritz Sherilyn C. , Baker Paul A.
Published: January 2018

High levels of biodiversity and endemism in ancient lakes have motivated research on evolutionary processes in these systems. Drill-core records from Lake Titicaca (Bolivia, Peru), an ancient lake in the high-elevation Altiplano, record the history of climate, landscape dynamics, and diatom evolution. That record was used to examine the patterns and drivers of morphological evolution of an endemic species complex of diatoms in the lake, theCyclostephanos andinuscomplex. In an attempt to delineate species within the complex based on morphology, no discernible evidence was found for species separation based on an ordination analysis of multiple characters, but multiple populations were detected based on the distribution of valve size in individual samples. Likelihood modeling of phyletic evolution showed that size evolved through punctuated change. Correlation of size trends with environmental variables indicates thatC. andinussize responded to regional environmental change driven by global processes that influenced Lake Titicaca by affecting lake level and thermal stratification.
Classification of multi-temporal spectral indices for crop type mapping: a case study in Coalville, UK
Authors: Palchowdhuri Y. , Valcarce-Diñeiro R. , King P. , Sanabria-Soto M.
Published: January 2018

Remote sensing (RS) offers an efficient and reliable means to map features on Earth. Crop type mapping using RS at various temporal and spatial resolutions plays an important role spanning from environmental to economical. The main objective of the current study was to evaluate the significance of optical data in a multi-temporal crop type classification-based on very high spatial resolution and high spatial resolution imagery. With this aim, three images from WorldView-3 and Sentinel-2 were acquired over Coalville (UK) between April and July 2016. Three vegetation indices (VIs); the normalized difference vegetation index, the green normalized difference vegetation index and soil adjusted vegetation index were generated using red, green and near-infrared spectral bands; then a supervised classification was performed using ground reference data collected from field surveys, Random forest (RF) and decision tree (DT) classification algorithms. Accuracy assessment was undertaken by comparing the classified output with the reference data. An overall accuracy of 91% and κ coefficient of 0·90 were estimated using the combination of RF and DT classification algorithms. Therefore, it can be concluded that integrating very high- and high-resolution imagery with different VIs can be implemented effectively to produce large-scale crop maps even with a limited temporal-dataset.
Decompensated labyrinthine weakness presenting as de novo peripheral vertigo: a discrete clinical entity?
Authors: Jahn A F
Published: January 2018

Objective:

A distinct subgroup of patients, presenting with apparently spontaneous onset of vertigo, is described.

Results:

Although vestibular evaluation revealed caloric weakness, the proximate cause of vertigo was not labyrinthine dysfunction, but rather the loss of vestibular compensation for an older and previously compensated labyrinthine injury.

Conclusion:

Instead of addressing the vestibular weakness, effective management needs to focus on the condition that has caused the loss of compensation.
Mixed views on the Philippines' Ifugao Rice Terraces: ‘Good’ versus ‘beautiful’ in the management of a UNESCO World Heritage site
Authors: Cagat Kathrine Ann D.
Published: January 2018

This article concerns divergent visualisations about the Ifugao Rice Terraces, a UNESCO World Heritage Site in the Philippines, which remain central to the economy and lives of the indigenous Ifugao. It focuses on the contrast between the Ifugao internal notion of ‘good’ and the visual emphasis on ‘beautiful’ associated with heritage bodies’ management and conservation of the terraced landscapes. These divergent visualisations frame various actors’ expectations of the terraces. In particular, this article features the community involvement in forums on mapping of core and buffer zones of the World Heritage clusters, and their responses to and criticisms of conservation initiatives in relation to their perceived impact on their livelihoods.
An Open-Source Storage Solution for Cryo-Electron Microscopy Samples
Authors: Ultee Eveline , Schenkel Fred , Yang Wen , Brenzinger Susanne , Depelteau Jamie S. , Briegel Ariane
Published: January 2018

Cryo-electron microscopy (cryo-EM) enables the study of biological structures in situ in great detail and to solve protein structures at Ångstrom level resolution. Due to recent advances in instrumentation and data processing, the field of cryo-EM is a rapidly growing. Access to facilities and national centers that house the state-of-the-art microscopes is limited due to the ever-rising demand, resulting in long wait times between sample preparation and data acquisition. To improve sample storage, we have developed a cryo-storage system with an efficient, high storage capacity that enables sample storage in a highly organized manner. This system is simple to use, cost-effective and easily adaptable for any type of grid storage box and dewar and any size cryo-EM laboratory.
CANONICALLY FIBERED SURFACES OF GENERAL TYPE
Authors: Lü Xin
Published: January 2018

In this paper, we construct the first examples of complex surfaces of general type with arbitrarily large geometric genus whose canonical maps induce non-hyperelliptic fibrations of genus $g=4$, and on the other hand, we prove that there is no complex surface of general type whose canonical map induces a hyperelliptic fibrations of genus $g\geqslant 4$ if the geometric genus is large.
Efficacy of MEK inhibition in a K-Ras-driven cholangiocarcinoma preclinical model
Authors: Dong Mingjie , Liu Xianqiong , Evert Katja , Utpatel Kirsten , Peters Michele , Zhang Shanshan , Xu Zhong , Che Li , Cigliano Antonio , Ribback Silvia , Dombrowski Frank , Cossu Antonio , Gordan John , Calvisi Diego F. , Evert Matthias , Liu Yan , Chen Xin
Published: January 2018

Intrahepatic cholangiocarcinoma (iCCA) is a deadly malignancy with limited treatment options. Gain-of-function mutations in K-Ras is a very frequent alteration, occurring in ~15 to 25% of human iCCA patients. Here, we established a new iCCA model by expressing activated forms of Notch1 (NICD) and K-Ras (K-RasV12D) in the mouse liver (K-Ras/NICD mice). Furthermore, we investigated the therapeutic potential of MEK inhibitors in vitro and in vivo using human CCA cell lines and K-Ras/NICD mice, respectively. Treatment with U0126, PD901, and Selumetinib MEK inhibitors triggered growth restraint in all CCA cell lines tested, with the most pronounced growth suppressive effects being observed in K-Ras mutant cells. Growth inhibition was due to reduction in proliferation and massive apoptosis. Furthermore, treatment of K-Ras/NICD tumor-bearing mice with PD901 resulted in stable disease. At the molecular level, PD901 efficiently inhibited ERK activation in K-Ras/NICD tumor cells, mainly leading to increased apoptosis. Altogether, our study demonstrates that K-Ras/NICD mice represent a novel and useful preclinical model to study K-Ras-driven iCCA development and the effectiveness of MEK inhibitors in counteracting this process. Our data support the usefulness of MEK inhibitors for the treatment of human iCCA.
PCDHGA9 acts as a tumor suppressor to induce tumor cell apoptosis and autophagy and inhibit the EMT process in human gastric cancer
Authors: Weng Junyong , Xiao Jingbo , Mi Yushuai , Fang Xu , Sun Yahuang , Li Shanbao , Qin Zhiwei , Li Xu , Liu Tingting , Zhao Senlin , Zhou Lisheng , Wen Yugang
Published: January 2018

The results of a cDNA  array revealed that protocadherin gamma subfamily A, 9 (PCDHGA9) was significantly decreased in SGC-7901 gastric cancer (GC) cells compared with GES-1 normal gastric cells and was strongly associated with the Wnt/β-catenin and transforming growth factor-β (TGF-β)/Smad2/3 signaling pathway. As a member of the cadherin family, PCDHGA9 functions in both cell–cell adhesion and nuclear signaling. However, its role in tumorigenicity or metastasis has not been reported. In the present study, we found that PCDHGA9 was decreased in GC tissues compared with corresponding normal mucosae and its expression was correlated with the GC TNM stage, the UICC stage, differentiation, relapse, and metastasis (p < 0.01). Multivariate Cox analysis revealed that PCDHGA9 was an independent prognostic indicator for overall survival (OS) and disease-free survival (DFS) (p < 0.01). The effects of PCDHGA9 on GC tumor growth and metastasis were examined both in vivo and in vitro. PCDHGA9 knockdown promoted GC cell proliferation, migration, and invasion, whereas PCDHGA9 overexpression inhibited GC tumor growth and metastasis but induced apoptosis, autophagy, and G1 cell cycle arrest. Furthermore, PCDHGA9 suppressed epithelial–mesenchymal transition (EMT) induced by TGF-β, decreased the phosphorylation of Smad2/3, and inhibited the nuclear translocation of pSmad2/3. Our results suggest that PCDHGA9 might interact with β-catenin to prevent β-catenin from dissociating in the cytoplasm and translocating to the nucleus. Moreover, PCDHGA9 overexpression restrained cell proliferation and reduced the nuclear β-catenin, an indicator of Wnt/β-catenin pathway activation, suggesting that PCDHGA9 negatively regulates Wnt signaling. Together, these data indicate that PCDHGA9 acts as a tumor suppressor with anti-proliferative activity and anti-invasive ability, and the reduction of PCDHGA9 could serve as an independent prognostic biomarker in GC.
Sensitivity to lunar cycles prior to the 2007 eruption of Ruapehu volcano
Authors: Girona Társilo , Huber Christian , Caudron Corentin
Published: January 2018

A long-standing question in Earth Science is the extent to which seismic and volcanic activity can be regulated by tidal stresses, a repeatable and predictable external excitation induced by the Moon-Sun gravitational force. Fortnightly tides, a ~14-day amplitude modulation of the daily tidal stresses that is associated to lunar cycles, have been suggested to affect volcano dynamics. However, previous studies found contradictory results and remain mostly inconclusive. Here we study how fortnightly tides have affected Ruapehu volcano (New Zealand) from 2004 to 2016 by analysing the rolling correlation between lunar cycles and seismic amplitude recorded close to the crater. The long-term (~1-year) correlation is found to increase significantly (up to confidence level of 5-sigma) during the ~3 months preceding the 2007 phreatic eruption of Ruapehu, thus revealing that the volcano is sensitive to fortnightly tides when it is prone to explode. We show through a mechanistic model that the real-time monitoring of seismic sensitivity to lunar cycles may help to detect the clogging of active volcanic vents, and thus to better forecast phreatic volcanic eruptions.
In vivo fluorescence bioimaging of ascorbic acid in mice: Development of an efficient probe consisting of phthalocyanine, TEMPO, and albumin
Authors: Yokoi Takanori , Otani Takayuki , Ishii Kazuyuki
Published: January 2018

After a groundbreaking study demonstrated that a high dose of ascorbic acid selectively kills cancer cells, the compound has been tested in the clinic against various forms of cancers, with some success. However, in vivo tracing of intravenously injected ascorbic acid has not been achieved. Herein, we successfully imaged ascorbic acid intravenously injected into mice based on the discovery of a novel, highly sensitive, and appropriately selective fluorescent probe consisting of silicon phthalocyanine (SiPc) and two 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) radicals, i.e., R2c. The radicals in this R2c were encapsulated in dimeric bovine serum albumin, and the sensitivity was >100-fold higher than those of other R2c-based probes. Ascorbic acid intravenously injected into mice was efficiently transported to the liver, heart, lung, and cholecyst. The present results provide opportunities to advance the use of ascorbic acid as cancer therapy.
Repression of Akt3 gene transcription by the tumor suppressor RIZ1
Authors: Liu Qingnan , Qu Xiaotian , Xie Xiaolei , He Pei , Huang Shi
Published: January 2018

RIZ1 has been studied as a tumor suppressor and may play a role in metabolic diseases related to the Western style diet, such as cancer and obesity. The Akt pathway is known to play a role in both cancer and obesity, and a link between Akt and RIZ1 has also been found. To better understand the role of RIZ1 in obesity and cancer, we investigated how RIZ1 regulates the expression of Akt3. We found that overexpression of RIZ1 in HEK293 cells reduced the expression of Akt3 protein. Luciferase reporter activity of Akt3 gene promoter was significantly reduced in cells co-transfected with RIZ1. Recombinant proteins of RIZ1 was able to bind the Akt3 promoter in vitro, and chromatin immunoprecipitation assay also demonstrated the ability of RIZ1 binding to the Akt3 promoter in vivo. Overexpression of RIZ1 increased H3K9 methylation on the Akt3 promoter. These results identify Akt3 as a target of RIZ1 regulation and expand our understanding of the Akt pathway in cancer and obesity.
Decoherence and control of a qubit in spin baths: an exact master equation study
Authors: Jing Jun , Wu Lian-Ao
Published: January 2018

In spin-based nanosystems for quantum information processing, electron spin qubits are subject to decoherence due to their interactions with nuclear spin environments. In this paper, we present an exact master equation for a central spin-1/2 system in time-dependent external fields and coupled to a spin-half bath in terms of hyperfine interaction. The master equation provides a unified description for free and controlled dynamics of the central spin and is formally independent of the details and size of spin environments. Different from the previous approaches, the master equation remains exact even in the presence of external control fields. Using the parameters for realistic nanosystems with nonzero nuclear spins, such as GaAs, we investigate the Overhauser’s effect on the decoherence dynamics of the central spin under different distributions of bath-spin frequencies and system-bath coupling strengths. Furthermore, we apply the leakage elimination operator, in a nonperturbative manner, to this system to suppress the decoherence induced by hyperfine interaction.
Central and cerebral haemodynamic changes after antihypertensive therapy in ischaemic stroke patients: A double-blind randomised trial
Authors: Choi Mun Hee , Lee Jin Soo , Lee Sung Eun , Lee Seong-Joon , Yoon Dukyong , Park Rae Woong , Hong Ji Man
Published: January 2018

Central and cerebral haemodynamic parameters can vary under similar brachial blood pressure (BP). We aimed to investigate the effects of antihypertensive agents on central and cerebral haemodynamic parameters in hypertensive patients with ischaemic stroke. The Fimasartan, Atenolol, and Valsartan On haemodynamic paRameters (FAVOR) study was conducted in a prospective, double-blinded manner. One hundred five patients were randomly administered atenolol, valsartan, or fimasartan during 12 weeks. We measured brachial, central, cerebral haemodynamic parameters and plasma N-terminal pro-brain natriuretic peptide (NT-proBNP) levels at baseline and after 12-week. Baseline haemodynamic parameters were balanced among the three groups. Even with similar brachial BP reduction, significantly lower central systolic BP (atenolol; 146.5 ± 18.8 vs. valsartan; 133.5 ± 20.7 vs. fimasartan; 133.6 ± 19.8 mmHg, p = 0.017) and augmentation index values (89.8 ± 13.2 vs. 80.6 ± 9.2 vs. 79.2 ± 11.6%; p = 0.001) were seen in the angiotensin receptor blockers (ARBs) groups. The pulsatility index on transcranial Doppler was significantly reduced in valsartan (p = 0.002) and fimasartan group (p = 0.008). Plasma NT-proBNP level was also significantly decreased in ARB groups, especially for the fimasartan group (37.8 ± 50.6 vs. 29.2 ± 36.9 vs.19.2 ± 27.8 pg/mL; p = 0.006). These findings suggest that short-term ARB administration would be favourable for ischaemic stroke patients with hypertension, permitting effective reduction of central pressure and dampening of cerebral pulsatility.
Inhibiting cancer cell hallmark features through nuclear export inhibition
Authors: Sun Qingxiang , Chen Xueqin , Zhou Qiao , Burstein Ezra , Yang Shengyong , Jia Da
Published: January 2018

Treating cancer through inhibition of nuclear export is one of the best examples of basic research translation into clinical application. Nuclear export factor chromosomal region maintenance 1 (CRM1; Xpo1 and exportin-1) controls cellular localization and function of numerous proteins that are critical for the development of many cancer hallmarks. The diverse actions of CRM1 are likely to explain the broad ranging anti-cancer potency of CRM1 inhibitors observed in pre-clinical studies and/or clinical trials (phase I–III) on both advanced-stage solid and hematological tumors. In this review, we compare and contrast the mechanisms of action of different CRM1 inhibitors, and discuss the potential benefit of unexplored non-covalent CRM1 inhibitors. This emerging field has uncovered that nuclear export inhibition is well poised as an attractive target towards low-toxicity broad-spectrum potent anti-cancer therapy.
A three-dimensional electrochemical paper-based analytical device for low-cost diagnostics
Authors: Punjiya Meera , Moon Chung Hee , Matharu Zimple , Rezaei Nejad Hojatollah , Sonkusale Sameer
Published: January 2018

A new 3D electrochemical paper-based analytical device with decreased sensor-to-sensor variation compared to conventional 2D devices is demonstrated with a custom designed CMOS potentiostat.
Palladium-catalyzed regioselective hydroboration of aryl alkenes with B2pin2
Authors: Huang Jiuzhong , Yan Wuxin , Tan Chaowei , Wu Wanqing , Jiang Huanfeng
Published: January 2018

A palladium-catalyzed regioselective hydroboration of aryl alkenes and isomerization–hydroboration of allyl benzene derivatives with stable B2pin2 has been developed.
PBP bridged [3]ferrocenophane: a bisphosphanylborane with a redox trigger
Authors: Lik Artur , Kargin Denis , Isenberg Stefan , Kelemen Zsolt , Pietschnig Rudolf , Helten Holger
Published: January 2018

An unprecedented PBP-bridged [3]ferrocenophane shows a unique intramolecular electron transfer process in the mono-oxidized state triggered by pyramidal inversion at phosphorus.
Determination of the critical mixing intensity for secondary nucleation of paracetamol in an oscillatory flow crystallizer
Authors: Cruz Patrícia , Rocha Fernando , Ferreira António
Published: January 2018

The critical mixing intensity for secondary nucleation of paracetamol was determined in an oscillatory flow crystallizer for the first time.
Modifying bis(triflimide) ionic liquids by dissolving early transition metal carbamates
Authors: Biancalana Lorenzo , Bresciani Giulio , Chiappe Cinzia , Marchetti Fabio , Pampaloni Guido , Pomelli Christian Silvio
Published: January 2018

Bis(triflimide) ionic liquids have been modified by dissolution ofN,N-dialkylcarbamates of early transition metals, the solubilities reaching the maximum value (1.46 M) with Nb(O2CNEt2)3. The solutions contain intact metal complexes, undergoing electrostatic interaction with the solvent cation.
Combinatorial selection of a two-dimensional 3d-TM-tetracyanoquinodimethane (TM-TCNQ) monolayer as a high-activity nanocatalyst for CO oxidation
Authors: Deng Qingming , Wu Tiantian , Chen Guibin , Hansen Heine Anton , Vegge Tejs
Published: January 2018

CO catalytic oxidation on Sc-TCNQ.
New carbon allotropes in sp + sp3 bonding networks consisting of C8 cubes
Authors: Wang Jian-Tao , Chen Changfeng , Mizuseki Hiroshi , Kawazoe Yoshiyuki
Published: January 2018

We identify using ab initio calculations new types of three-dimensional carbon allotrope constructed by inserting acetylenic or diacetylenic bonds into a body-centered cubic C8 lattice.
Preparation of Eu(iii) acetylacetonate-doped well-defined titania particles with efficient photoluminescence properties
Authors: Shiba Kota , Kataoka Takuya , Tagaya Motohiro
Published: January 2018

Eu(iii) acetylacetonate-doped well-defined titania particles were synthesized to demonstrate composition dependent efficient luminescence properties.
Carrier-doped aromatic hydrocarbons: a new platform in condensed matter chemistry and physics
Authors: Heguri Satoshi , Tanigaki Katsumi
Published: January 2018

High quality bulk samples of the first four polyacenes, naphthalene, anthracene, tetracene, and pentacene, doped with alkali metal in 1 : 1 and 1 : 2 stoichiometries were prepared and their fundamental properties were systematically studied. The carrier doped typical aromatic hydrocarbons showed a large variety of properties as well as charge transfer complexes and metal doped fullerides. We open a new category in condensed matter chemistry and physics.
Extraordinary sensitivity for H2S and Fe(iii) sensing in aqueous medium by Al-MIL-53-N3metal–organic framework:in vitroandin vivoapplications of H2S sensing
Authors: Das Aniruddha , Banesh Sooram , Trivedi Vishal , Biswas Shyam
Published: January 2018

An Al-MIL-53-N3MOF sensor showing extraordinary sensitivity for H2S and Fe(iii) is presented. Its cell imaging capability is also demonstrated.
Homoleptic U(iii) and U(iv) amidate complexes
Authors: Straub M. D. , Hohloch S. , Minasian S. G. , Arnold J.
Published: January 2018

Homoleptic U(iv) and U(iii) amidate complexes have been isolated and characterized; these species undergo an unusual and reversible change in coordination number upon reduction/oxidation.
Efficient synthesis of 1,2-benzisothiazoles from o-haloarylamidines and elemental sulfur via N–S/C–S bond formation under transition-metal-free conditions
Authors: Xie Hao , Li Guozheng , Zhang Feng , Xiao Fuhong , Deng Guo-Jun
Published: January 2018

Facile synthesis of 1,2-benzisothiazoles from amidines and elemental sulfur via N–S/C–S bond formation under transition-metal-free conditions has been developed with good tolerance of a broad range of functional groups.
Simultaneous uniaxial extensional deformation and cylindrical confinement of block copolymers using non-equilibrium molecular dynamics
Authors: Shebert George L. , Joo Yong Lak
Published: January 2018

Using coarse-grained nonequilibrium molecular dynamics, symmetric block copolymers are simulated under the combined effects of cylindrical confinement and uniaxial extensional deformation.
Self-diffusiophoresis induced by fluid interfaces
Authors: Malgaretti P. , Popescu M. N. , Dietrich S.
Published: January 2018

The influence of a fluid–fluid interface on the self-phoresis of chemically active spherical colloids is analyzed for axially symmetric configurations. Distinct from the case of hard walls, motion of the particle either towards or away from the interface can be induced by tuning the physical properties of one of the two fluid phases.
Cosmic ray and neutrino emission from gamma-ray bursts with a nuclear cascade
Authors: Biehl D. , Boncioli D. , Fedynitch A. , Winter W.
Published: January 2018

Aim. We discuss neutrino and cosmic ray emission from gamma-ray bursts (GRBs) with the injection of nuclei, where we take into account that a nuclear cascade from photodisintegration can fully develop in the source. Our main objective is to test whether recent results from the IceCube and the Pierre Auger Observatory can be accommodated within the paradigm that GRBs are the sources of ultra-high-energy cosmic rays (UHECRs).

Methods. We simulate this scenario in a combined source-propagation model. While our key results are obtained using an internal shock model of the source, we discuss how the secondary emission from a GRB shell can be interpreted in terms of other astrophysical models.

Results. We demonstrate that the expected neutrino flux from GRBs weakly depends on the injection composition for the same injection spectra and luminosities, which implies that prompt neutrinos from GRBs can efficiently test the GRB-UHECR paradigm even if the UHECRs are nuclei. We show that the UHECR spectrum and composition, as measured by the Pierre Auger Observatory, can be self-consistently reproduced. In an attempt to describe the energy range including the ankle, we find tension with the IceCube bounds from the GRB stacking analyses. In an alternative scenario, where only the UHECRs beyond the ankle originate from GRBs, the requirement for a joint description of cosmic ray and neutrino observations favors lower luminosities, which does not correspond to the typical expectation from γ-ray observations.
Refraction in exoplanet atmospheres
Authors: Alp D. , Demory B.-O.
Published: January 2018

Context.Refraction deflects photons that pass through atmospheres, which affects transit light curves. Refraction thus provides an avenue to probe physical properties of exoplanet atmospheres and to constrain the presence of clouds and hazes. In addition, an effective surface can be imposed by refraction, thereby limiting the pressure levels probed by transmission spectroscopy.

Aims.The main objective of the paper is to model the effects of refraction on photometric light curves for realistic planets and to explore the dependencies on atmospheric physical parameters. We also explore under which circumstances transmission spectra are significantly affected by refraction. Finally, we search for refraction signatures in photometric residuals inKeplerdata.

Methods.We use the model of Hui & Seager (2002, ApJ, 572, 540) to compute deflection angles and refraction transit light curves, allowing us to explore the parameter space of atmospheric properties. The observational search is performed by stacking large samples of transit light curves fromKepler.

Results.We find that out-of-transit refraction shoulders are the most easily observable features, which can reach peak amplitudes of ~10 parts per million (ppm) for planets around Sun-like stars. More typical amplitudes are a few ppm or less for Jovians and at the sub-ppm level for super-Earths. In-transit, ingress, and egress refraction features are challenging to detect because of the short timescales and degeneracies with other transit model parameters. Interestingly, the signal-to-noise ratio of any refraction residuals for planets orbiting Sun-like hosts are expected to be similar for planets orbiting red dwarfs and ultra-cool stars. We also find that the maximum depth probed by transmission spectroscopy is not limited by refraction for weakly lensing planets, but that the incidence of refraction can vary significantly for strongly lensing planets. We find no signs of refraction features in the stackedKeplerlight curves, which is in agreement with our model predictions.
Chromospheric heating during flux emergence in the solar atmosphere
Authors: Leenaarts Jorrit , de la Cruz Rodríguez Jaime , Danilovic Sanja , Scharmer Göran , Carlsson Mats
Published: January 2018

Context. The radiative losses in the solar chromosphere vary from 4 kW m−2 in the quiet Sun, to 20 kW m−2 in active regions. The mechanisms that transport non-thermal energy to and deposit it in the chromosphere are still not understood.

Aim. We aim to investigate the atmospheric structure and heating of the solar chromosphere in an emerging flux region.

Methods. We have used observations taken with the CHROMIS and CRISP instruments on the Swedish 1-m Solar Telescope in the Ca II K , Ca II 854.2 nm, Hα, and Fe I 630.1 nm and 630.2 nm lines. We analysed the various line profiles and in addition perform multi-line, multi-species, non-local thermodynamic equilibrium (non-LTE) inversions to estimate the spatial and temporal variation of the chromospheric structure.

Results. We investigate which spectral features of Ca II K contribute to the frequency-integrated Ca II K brightness, which we use as a tracer of chromospheric radiative losses. The majority of the radiative losses are not associated with localised high-Ca II K-brightness events, but instead with a more gentle, spatially extended, and persistent heating. The frequency-integrated Ca II K brightness correlates strongly with the total linear polarization in the Ca II 854.2 nm, while the Ca II K profile shapes indicate that the bulk of the radiative losses occur in the lower chromosphere. Non-LTE inversions indicate a transition from heating concentrated around photospheric magnetic elements below log τ500 = −3 to a more space-filling and time-persistent heating above log τ500 = −4. The inferred gas temperature at log τ500 = −3.8 correlates strongly with the total linear polarization in the Ca II 854.2 nm line, suggesting that that the heating rate correlates with the strength of the horizontal magnetic field in the low chromosphere.
Access to 5(6→7)abeo-Steroids through Benzilic Acid Rearrangement of i-Steroids
Authors: Heretsch Philipp , Noack Florian , Hartmayer Bence
Published: January 2018

Benzilic acid rearrangement of i-steroid ketones and their subsequent opening gives access to 5(6→7)abeo-steroids. The functional group tolerance is demonstrated by several examples, including substrates with additional olefinic groups. The method opens a potential route to the synthesis of complex natural products such as solanioic acid from abundant steroid starting materials like ergosterol.
Rh(I)-Catalyzed Intramolecular [3+2] Cycloaddition of trans-2-Allene-Vinylcyclopropanes
Authors: Yu Zhi-Xiang , Liu Cheng-Hang
Published: January 2018

An intramolecular [3+2] cycloaddition of trans-2-allene-­vinylcyclopropanes for the synthesis of bicyclo[3.3.0]octane derivatives is developed.
Theoretical study of tetrahedral site occupation by hydrogen in Pd nanoparticles
Authors: Ishimoto Takayoshi , Koyama Michihisa
Published: January 2018

To understand the enhanced effects and new hydrogen absorption properties of metal nanoparticles, we theoretically investigated the hydrogen absorption in Pd nanoparticles, adopting the Pd405 model of ca. 2.5 nm by using density functional theory. Pd405 showed inhomogeneous geometric features, especially near the surface region. The hydrogen absorptions in octahedral (O) and tetrahedral (T) sites near the core region were stable and unstable, respectively, similar to the Pd bulk. We clearly demonstrated the possibility of hydrogen absorption in T sites near the surface of Pd405. The flexible volume change and the difference in hydrogen position relative to the center of mass of the T site that we observed are important factors for stable hydrogen absorption in T sites of Pd nanoparticles. In addition, we discuss the differences in hydrogen diffusion mechanisms in the core and near surface regions, based on the stability of hydrogen absorption in O and T sites.
Modification of graphene electronic properties via controllable gas-phase doping with copper chloride
Authors: Rybin Maxim G. , Islamova Vera R. , Obraztsova Ekaterina A. , Obraztsova Elena D.
Published: January 2018

Molecular doping is an efficient, non-destructive, and simple method for changing the electronic structure of materials. Here, we present a simple air ambient vapor deposition method for functionalization of pristine graphene with a strong electron acceptor: copper chloride. The doped graphene was characterized by Raman spectroscopy, UV-vis-NIR optical absorption spectroscopy, scanning electron microscopy, and electro-physical measurements performed using the 4-probe method. The effect of charge transfer from graphene to a dopant results in shifting the Fermi level in doped graphene. The change of the electronic structure of doped graphene was confirmed by the tangential Raman peak (G-peak) shift and by the appearance of the gap in the UV-vis-NIR spectrum after doping. Moreover, the charge transfer resulted in a substantial decrease in electrical sheet resistance depending on the doping level. At the highest concentration of copper chloride, a Fermi level shift into the valence band up to 0.64 eV and a decrease in the sheet resistance value by 2.36 times were observed (from 888 Ω/sq to 376 Ω/sq for a single graphene layer with 97% of transparency).
Relationship between global and segmental dynamics of poly(butylene oxide) studied by broadband dielectric spectroscopy
Authors: Urakawa Osamu , Yamane Minoru , Tomie Shota , Inoue Tadashi , Shikata Toshiyuki , Adachi Keiichiro
Published: January 2018

Relationship between segmental relaxation and normal-mode relaxation has been studied for molten poly(butylene oxide)s having various molecular weights by broadband dielectric spectroscopy over a wide temperature (T) range. We found that T dependence of the segmental relaxation time, τs, was weaker than the normal mode time, τn, at high T(>250 K ∼ Tg + 50 K), and the τn/τs ratio systematically decreased with increasing temperature. This high temperature complexity, whose mechanism has not been discussed in detail so far, was quantitatively explained by assuming the two step processes: local conformation change of polymers (elementary process) occurs first, and then the motion of a segment unit (second process) occurs. It was also found that the elementary process was strongly correlated with the experimentally observed β-relaxation.
Observation of unusual critical region behavior in the magnetic susceptibility of EuSe
Authors: Bykovetz N. , Klein J. , Lin C. L.
Published: January 2018

The Europium Chalcogenides (EuCh: EuO, EuS, EuSe, and EuTe) have been regarded as model examples of simple, cubic, Heisenberg exchange coupled magnetic systems, with a ferromagnetic nearest-neighbor exchange constant J1 and an antiferromagnetic next-nearest-neighbor constant J2. Unlike the other EuCh, EuSe exhibits a range of complex magnetic behaviors, the latter being attributed to EuSe being near the point where J2=-J1, where its magnetism appears to consist of nearly de-coupled 2D ferromagnetic sheets. Analysis of precision SQUID measurements of the magnetic susceptibility χ in EuSe showed that in the region from ∼Tc to ∼2Tc, a fit of the data to the critical equation χ = χ2Tc(T/Tc-1)-γ gives γ=2.0, an exponent not predicted by any current theory. Additionally, this fit predicts that Tc should be ∼0K. We tentatively interpret this by saying that in the paramagnetic region the system "thinks" EuSe should not order above T=0. Tc=0K is predicted by the Mermin-Wagner theorem (MW) for Heisenberg-coupled 2D magnetic systems, and we can show that when J2=-J1, MW can also be applied to the J1, J2 exchange model of the EuCh to give a rigorous Tc=0 prediction. Under 10 kbar applied pressure EuSe exhibits a different γ and fitted Tc. An additional, and rather strange, critical-region effect was discovered. The EuSe sample was found to exhibit a relaxation effect in a small range of temperatures, just above and just below the actual Tc of 4.7K, with time constants of up to 5 minutes. We cannot yet fully explain this observed macroscopic effect.
Spin-to-charge conversion in 2D electron gas and single-layer graphene devices
Authors: Ramos J. G. G. S. , Vasconcelos T. C. , Barbosa A. L. R.
Published: January 2018

We investigate the spin-to-charge conversion emerging from a mesoscopic device connected to multiple terminals. We obtain analytical expressions to the characteristic coefficient of spin-to-charge conversion, which are applied in two kinds of ballistic chaotic quantum dots at low temperature. We perform analytical diagrammatic calculations in the universal regime for two-dimensional electron gas and single-layer graphene with the strong spin-orbit interaction in the universal regime. Furthermore, our analytical results are confirmed by numerical simulations. Finally, we connect our analytical findings to recent experimental measures giving a conceptual explanation about the apparent discrepancies between them.
Multiband quasi-perfect low-frequency sound absorber based on double-channel Mie resonator
Authors: Long Houyou , Gao Shuxiang , Cheng Ying , Liu Xiaojun
Published: January 2018

Metamaterial absorbers have recently been developed to act as efficient sound absorption components of subwavelength dimensions. However, the working frequency has so far been mainly limited to a single narrow band. Here, we demonstrate a multiband quasi-perfect absorber constructed by a double-channel Mie resonator (DMR) in a unique configuration. By attentively tuning the leakage factor to match the loss factor at multi-order monopolar and dipolar resonances of DMR simultaneously, a series of absorptive peaks with near-unity absorptances have been achieved in both numerical simulation and the experimental measurement. Our approach gives a simple platform for extending the response of metamaterial devices from the single band to the multiband without superimposing resonant elements in multiple configurations, which allows us to envision acoustic devices with versatile applications.
Spin-dependent electronic transport characteristics in Fe4N/BiFeO3/Fe4N perpendicular magnetic tunnel junctions
Authors: Yin Li , Wang Xiaocha , Mi Wenbo
Published: January 2018

Perpendicular magnetic tunnel junctions (MTJs) have attracted increasing attention owing to the low energy consumption and wide application prospects. Herewith, against Julliere's formula, an inverse tunnel magnetoresistance (TMR) appears in tetragonal Fe4N/BiFeO3/Fe4N perpendicular MTJs, which is attributed to the binding between the interface resonant tunneling state and central (bordered) hot spots. Especially, antiferromagnetic BiFeO3 shows an extra spin-polarized resonant state in the barrier, which provides a magnetic-barrier factor to affect the tunneling transport in MTJs. Meanwhile, due to the spin-polarized transport in Fe4N/BiFeO3/Fe4N MTJs, the sign of TMR can be tuned by the applied bias. The tunable TMR and resonant magnetic barrier effect pave the way for clarifying the tunneling transport in other junctions and spintronic devices.
A maximum entropy principle for inferring the distribution of 3D plasmoids
Authors: Lingam Manasvi , Comisso Luca
Published: January 2018

The principle of maximum entropy, a powerful and general method for inferring the distribution function given a set of constraints, is applied to deduce the overall distribution of 3D plasmoids (flux ropes/tubes) for systems where resistive MHD is applicable and large numbers of plasmoids are produced. The analysis is undertaken for the 3D case, with mass, total flux, and velocity serving as the variables of interest, on account of their physical and observational relevance. The distribution functions for the mass, width, total flux, and helicity exhibit a power-law behavior with exponents of −4/3, −2, −3, and −2, respectively, for small values, whilst all of them display an exponential falloff for large values. In contrast, the velocity distribution, as a function of v=|v|, is shown to be flat for v→0, and becomes a power law with an exponent of −7/3 for v→∞. Most of these results are nearly independent of the free parameters involved in this specific problem. A preliminary comparison of our results with the observational evidence is presented, and some of the ensuing space and astrophysical implications are briefly discussed.