bluuebunny/crossref_metadata_2025_split huggingface dataset:
Unified model for singlet fission within a non-conjugated covalent pentacene dimer
Authors: Basel Bettina S. , Zirzlmeier Johannes , Hetzer Constantin , Phelan Brian T. , Krzyaniak Matthew D. , Reddy S. Rajagopala , Coto Pedro B. , Horwitz Noah E. , Young Ryan M. , White Fraser J. , Hampel Frank , Clark Timothy , Thoss Michael , Tykwinski Rik R. , Wasielewski Michael R. , Guldi Dirk M. 
Published: May 2017

AbstractWhen molecular dimers, crystalline films or molecular aggregates absorb a photon to produce a singlet exciton, spin-allowed singlet fission may produce two triplet excitons that can be used to generate two electron–hole pairs, leading to a predicted ∼50% enhancement in maximum solar cell performance. The singlet fission mechanism is still not well understood. Here we report on the use of time-resolved optical and electron paramagnetic resonance spectroscopy to probe singlet fission in a pentacene dimer linked by a non-conjugated spacer. We observe the key intermediates in the singlet fission process, including the formation and decay of a quintet state that precedes formation of the pentacene triplet excitons. Using these combined data, we develop a single kinetic model that describes the data over seven temporal orders of magnitude both at room and cryogenic temperatures.
High conductance values in π-folded molecular junctions
Authors: Carini Marco , Ruiz Marta P. , Usabiaga Imanol , Fernández José A. , Cocinero Emilio J. , Melle-Franco Manuel , Diez-Perez Ismael , Mateo-Alonso Aurelio 
Published: May 2017

AbstractFolding processes play a crucial role in the development of function in biomacromolecules. Recreating this feature on synthetic systems would not only allow understanding and reproducing biological functions but also developing new functions. This has inspired the development of conformationally ordered synthetic oligomers known as foldamers. Herein, a new family of foldamers, consisting of an increasing number of anthracene units that adopt a folded sigmoidal conformation by a combination of intramolecular hydrogen bonds and aromatic interactions, is reported. Such folding process opens up an efficient through-space charge transport channel across the interacting anthracene moieties. In fact, single-molecule conductance measurements carried out on this series of foldamers, using the scanning tunnelling microscopy-based break-junction technique, reveal exceptionally high conductance values in the order of 10−1G0 and a low length decay constant of 0.02 Å−1 that exceed the values observed in molecular junctions that make use of through-space charge transport pathways.
Genetic architecture of epigenetic and neuronal ageing rates in human brain regions
Authors: Lu Ake T. , Hannon Eilis , Levine Morgan E. , Crimmins Eileen M. , Lunnon Katie , Mill Jonathan , Geschwind Daniel H. , Horvath Steve 
Published: May 2017

AbstractIdentifying genes regulating the pace of epigenetic ageing represents a new frontier in genome-wide association studies (GWASs). Here using 1,796 brain samples from 1,163 individuals, we carry out a GWAS of two DNA methylation-based biomarkers of brain age: the epigenetic ageing rate and estimated proportion of neurons. Locus 17q11.2 is significantly associated (P=4.5 × 10−9) with the ageing rate across five brain regions and harbours a cis-expression quantitative trait locus for EFCAB5 (P=3.4 × 10−20). Locus 1p36.12 is significantly associated (P=2.2 × 10−8) with epigenetic ageing of the prefrontal cortex, independent of the proportion of neurons. Our GWAS of the proportion of neurons identified two genome-wide significant loci (10q26 and 12p13.31) and resulted in a gene set that overlaps significantly with sets found by GWAS of age-related macular degeneration (P=1.4 × 10−12), ulcerative colitis (P<1.0 × 10−20), type 2 diabetes (P=2.8 × 10−13), hip/waist circumference in men (P=1.1 × 10−9), schizophrenia (P=1.6 × 10−9), cognitive decline (P=5.3 × 10−4) and Parkinson’s disease (P=8.6 × 10−3).
Nanometric holograms based on a topological insulator material
Authors: Yue Zengji , Xue Gaolei , Liu Juan , Wang Yongtian , Gu Min 
Published: May 2017

AbstractHolography has extremely extensive applications in conventional optical instruments spanning optical microscopy and imaging, three-dimensional displays and metrology. To integrate holography with modern low-dimensional electronic devices, holograms need to be thinned to a nanometric scale. However, to keep a pronounced phase shift modulation, the thickness of holograms has been generally limited to the optical wavelength scale, which hinders their integration with ultrathin electronic devices. Here, we break this limit and achieve 60 nm holograms using a topological insulator material. We discover that nanometric topological insulator thin films act as an intrinsic optical resonant cavity due to the unequal refractive indices in their metallic surfaces and bulk. The resonant cavity leads to enhancement of phase shifts and thus the holographic imaging. Our work paves a way towards integrating holography with flat electronic devices for optical imaging, data storage and information security.
The origin and degassing history of the Earth's atmosphere revealed by Archean xenon
Authors: Avice Guillaume , Marty Bernard , Burgess Ray 
Published: May 2017

AbstractXenon (Xe) is an exceptional tracer for investigating the origin and fate of volatile elements on Earth. The initial isotopic composition of atmospheric Xe remains unknown, as do the mechanisms involved in its depletion and isotopic fractionation compared with other reservoirs in the solar system. Here we present high precision analyses of noble gases trapped in fluid inclusions of Archean quartz (Barberton, South Africa) that reveal the isotopic composition of the paleo-atmosphere at ≈3.3 Ga. The Archean atmospheric Xe is mass-dependently fractionated by 12.9±2.4 ‰ u−1 (± 2σ, s.d.) relative to the modern atmosphere. The lower than today 129Xe excess requires a degassing rate of radiogenic Xe from the mantle higher than at present. The primordial Xe component delivered to the Earth's atmosphere is distinct from Solar or Chondritic Xe but similar to a theoretical component called U-Xe. Comets may have brought this component to the Earth's atmosphere during the last stages of terrestrial accretion.
Physical activity and risk of comorbidities in patients with chronic obstructive pulmonary disease: a cohort study
Authors: Yu Tsung , ter Riet Gerben , Puhan Milo A. , Frei Anja 
Published: May 2017

AbstractMulti-morbidity is common in patients with chronic obstructive pulmonary disease and low levels of physical activity are hypothesized to be an important risk factor. The current study aimed to assess the longitudinal association between physical activity and risk of seven categories of comorbidity in chronic obstructive pulmonary disease patients. The study included 409 patients from primary care practice in the Netherlands and Switzerland. We assessed physical activity using the Longitudinal Ageing Study Amsterdam Physical Activity Questionnaire at baseline and followed patients for up to 5 years. During follow-up, patients reported their comorbidities (cardiovascular, neurological, endocrine, musculoskeletal, malignant, and infectious diseases) and completed the Hospital Anxiety and Depression Scale questionnaire for mental health assessment. We implemented multinomial logistic regression (an approximation to discrete time survival model using death as a competing risk) for our analysis. Study results did not suggest a statistically significant association of baseline physical activity with the development of seven categories of comorbidity. However, when we focused on depression and anxiety symptoms, we found that higher levels of physical activity at baseline were associated with a lower risk for depression (adjusted hazard ratio, 0.85; 0.75–0.95; p = 0.005) and anxiety (adjusted hazard ratio, 0.89; 0.79–1.00; p = 0.045). In chronic obstructive pulmonary disease patients, those with high physical activity are less likely to develop depression or anxiety symptoms over time. Increasing physical activity in chronic obstructive pulmonary disease patients may be an approach for testing to lower the burden from incident depression and anxiety.
Towards new cholera prophylactics and treatment: Crystal structures of bacterial enterotoxins in complex with GM1 mimics
Authors: Heggelund Julie Elisabeth , Mackenzie Alasdair , Martinsen Tobias , Heim Joel Benjamin , Cheshev Pavel , Bernardi Anna , Krengel Ute 
Published: May 2017

AbstractCholera is a life-threatening disease in many countries, and new drugs are clearly needed. C-glycosidic antagonists may serve such a purpose. Here we report atomic-resolution crystal structures of three such compounds in complexes with the cholera toxin. The structures give unprecedented atomic details of the molecular interactions and show how the inhibitors efficiently block the GM1 binding site. These molecules are well suited for development into low-cost prophylactic drugs, due to their relatively easy synthesis and their resistance to glycolytic enzymes. One of the compounds links two toxin B-pentamers in the crystal structure, which may yield improved inhibition through the formation of toxin aggregates. These structures can spark the improved design of GM1 mimics, either alone or as multivalent inhibitors connecting multiple GM1-binding sites. Future developments may further include compounds that link the primary and secondary binding sites. Serving as decoys, receptor mimics may lessen symptoms while avoiding the use of antibiotics.
Angiopoietin-1 enhances neutrophil chemotaxis in vitro and migration in vivo through interaction with CD18 and release of CCL4
Authors: Burnett Amanda , Gomez Ingrid , De Leon David Davila , Ariaans Mark , Progias Pavlos , Kammerer Richard A. , Velasco Guillermo , Marron Marie , Hellewell Paul , Ridger Victoria 
Published: May 2017

AbstractAngiopoietins are a family of growth factors that are ligands for the tyrosine kinase receptor, Tie2. Angiopoietin 1 (Ang-1) is agonistic for Tie2, plays a key role in blood vessel maturation and stability and has been shown to possess anti-inflammatory properties. However, Tie2 expression has been demonstrated on human neutrophils and the observation that neutrophils migrate in response to Ang-1in vitrohas confounded research into its exact role in inflammation as well as its potential use as a therapeutic agent. We used a mouse model of peritoneal neutrophilic inflammation to determine if Ang-1 could stimulate neutrophil migrationin vivo. Tie2 expression was demonstrated on mouse neutrophils. In addition, recombinant human Ang-1 induced significant chemotaxis of isolated mouse neutrophils in a Tie2- and CD18-dependent manner. Subsequently, co-immunoprecipitation of Ang-1 and CD18 demonstrated their interaction. Intraperitoneal injection of an engineered angiopoietin-1, MAT.Ang-1, induced significant neutrophil migration into the peritoneum and a significant increase in the levels of CCL4 in peritoneal lavage fluid. Depletion of resident peritoneal macrophages prior to, or concomitant injections of an anti-CCL4 antibody with MAT.Ang-1 resulted in a significant reduction in neutrophil recruitment. These data indicate a pro-inflammatory role for Ang-1 with respect to neutrophil recruitment.
Optimizing the thermoelectric performance of graphene nano-ribbons without degrading the electronic properties
Authors: Tran Van-Truong , Saint-Martin Jérôme , Dollfus Philippe , Volz Sebastian 
Published: May 2017

AbstractThe enhancement of thermoelectric figure of merit ZT requires to either increase the power factor or reduce the phonon conductance, or even both. In graphene, the high phonon thermal conductivity is the main factor limiting the thermoelectric conversion. The common strategy to enhance ZT is therefore to introduce phonon scatterers to suppress the phonon conductance while retaining high electrical conductance and Seebeck coefficient. Although thermoelectric performance is eventually enhanced, all studies based on this strategy show a significant reduction of the electrical conductance. In this study we demonstrate that appropriate sources of disorder, including isotopes and vacancies at lowest electron density positions, can be used as phonon scatterers to reduce the phonon conductance in graphene ribbons without degrading the electrical conductance, particularly in the low-energy region which is the most important range for device operation. By means of atomistic calculations we show that the natural electronic properties of graphene ribbons can be fully preserved while their thermoelectric efficiency is strongly enhanced. For ribbons of width M = 5 dimer lines, room-temperature ZT is enhanced from less than 0.26 to more than 2.5. This study is likely to set the milestones of a new generation of nano-devices with dual electronic/thermoelectric functionalities.
Callistemenonone A, a novel dearomatic dibenzofuran-type acylphloroglucinol with antimicrobial activity from Callistemon viminalis
Authors: Xiang Yu-Qing , Liu Hong-Xin , Zhao Li-Yun , Xu Zhi-Fang , Tan Hai-Bo , Qiu Sheng-Xiang 
Published: May 2017

AbstractA new acylphloroglucinol with a novel architecture including an unprecedented dearomatic dibenzofuran core, named callistemenonone A (1), was isolated from the leaves of Callistemon viminalis (Myrtaceae). The structure was fully characterized on the basis of extensive spectroscopic analysis, including UV, HRESIMS, as well as 1D and 2D NMR spectral data (HSQC, HMBC, and ROESY). The deduced structure represents the first example of a natural dibenzofuran with two phenyl moieties coupling through tertiary hydroxy and ketal carbons. A plausible biogenetic pathway involving oxidative coupling and dearomatization as key steps is proposed to account for the biosynthesis of this novel class of dibenzofuran. Moreover, antimicrobial assays, in conjunction with the time-killing and biophysical studies, revealed that 1 exerted potent bactericidal activity against a panel of methicillin resistant pathogenic microbes with a unique mechanism.
PKC-δ isoform plays a crucial role in Tat-TLR4 signalling pathway to activate NF-κB and CXCL8 production
Authors: Serrero Manutea , Planès Rémi , Bahraoui Elmostafa 
Published: May 2017

AbstractHIV-1 Tat protein induces the production of CXCL8 chemokine in a TLR4/MD2 and PKC dependent manner. The objective of this study was to understand whether these two pathways were distinct or constituted a single common pathway, and to determine the nature of the PKC isoforms involved and their interrelation with the activation of NF-κB and CXCL8 gene product expression. Here, we show that Tat-induced CXCL8 production is essentially dependent on the activation of PKC delta isoform, as shown a) by the capacity of PKC delta dominant negative (DN), and Rottlerin, a selective PKC delta pharmacological inhibitor, to inhibit Tat-induced CXCL8 production and b) by the ability of the constitutively active (CAT) isoform of PKC delta to induce CXCL8 production in a HEK cell line in the absence of Tat stimulation. The finding that comparable amounts of CXCL8 were produced following stimulation with either Tat protein, PKC-delta CAT transfection, or both, argue for the implication of one common pathway where PKC delta is activated downstream of TLR4 recruitment and leads to the activation of NF-κB. Altogether, our results underline the crucial role of PKC delta isoform in activating gene expression of CXCL8, a cytokine largely implicated in the physiopathology of HIV-1 infection.
Sensorimotor adaptation as a behavioural biomarker of early spinocerebellar ataxia type 6
Authors: Panouillères Muriel T. N. , Joundi Raed A. , Benitez-Rivero Sonia , Cheeran Binith , Butler Christopher R. , Németh Andrea H. , Miall R. Chris , Jenkinson Ned 
Published: May 2017

AbstractEarly detection of the behavioural deficits of neurodegenerative diseases may help to describe the pathogenesis of such diseases and establish important biomarkers of disease progression. The aim of this study was to identify how sensorimotor adaptation of the upper limb, a cerebellar-dependent process restoring movement accuracy after introduction of a perturbation, is affected at the pre-clinical and clinical stages of spinocerebellar ataxia type 6 (SCA6), an inherited neurodegenerative disease. We demonstrate that initial adaptation to the perturbation was significantly impaired in the eighteen individuals with clinical motor symptoms but mostly preserved in the five pre-clinical individuals. Moreover, the amount of error reduction correlated with the clinical symptoms, with the most symptomatic patients adapting the least. Finally both pre-clinical and clinical individuals showed significantly reduced de-adaptation performance after the perturbation was removed in comparison to the control participants. Thus, in this large study of motor features in SCA6, we provide novel evidence for the existence of subclinical motor dysfunction at a pre-clinical stage of SCA6. Our findings show that testing sensorimotor de-adaptation could provide a potential predictor of future motor deficits in SCA6.
Strontium-loaded titania nanotube arrays repress osteoclast differentiation through multiple signalling pathways: In vitro and in vivo studies
Authors: Mi Baoguo , Xiong Wei , Xu Na , Guan Hanfeng , Fang Zhong , Liao Hui , Zhang Yong , Gao Biao , Xiao Xiang , Fu Jijiang , Li Feng 
Published: May 2017

AbstractThe loosening of implants is an important clinical issue, particularly for patients with osteoporosis. In these patients, an implant should preferably both promote osteoblast differentiation and repress osteoclastic resorption. In the present study, we fabricated coatings containing TiO2 nanotubes (NTs) incorporated with strontium (Sr) on titanium (Ti) surfaces through hydrothermal treatment. The amount of loaded Sr was controlled by hydrothermally treating the samples in a Sr(OH)2 solution for 1 and 3 h (samples NT-Sr1h and NT-Sr3h, respectively) and found that both types of NT-Sr samples inhibited osteoclast differentiation by reducing the expression of osteoclast marker genes. Additionally, this inhibitory effect was mainly attributed to suppression of RANKL-induced activation of nuclear factor-κB (NF-κB). Moreover, NT-Sr also inhibited the Akt and nuclear factor of activated T-cell cytoplasmic 1 (NFATc1) signalling pathways. Interestingly, we also found that NT-Sr promoted RANKL-induced extracellular signal-regulated kinase (ERK) phosphorylation. Using ovariectomised rats as a model, we observed that NT-Sr prevented bone loss in vivo. In conclusion, our findings demonstrate that NT-Sr might effectively inhibit osteoclast differentiation by repressing the NF-κB and Akt/NFATc1 pathways and by negatively regulating the ERK pathway in vitro and in vivo.
Cooperation of Oncolytic Herpes Virotherapy and PD-1 Blockade in Murine Rhabdomyosarcoma Models
Authors: Chen Chun-Yu , Wang Pin-Yi , Hutzen Brian , Sprague Les , Swain Hayley M. , Love Julia K. , Stanek Joseph R. , Boon Louis , Conner Joe , Cripe Timothy P. 
Published: May 2017

AbstractOncolytic virotherapy is an effective immunotherapeutic approach for cancer treatment via a multistep process including direct tumor cell lysis, induction of cytotoxic or apoptosis-sensitizing cytokines and promotion of antitumor T cell responses. Solid tumors limit the effectiveness of immunotherapeutics in diverse ways such as secretion of immunosuppressive cytokines and expression of immune inhibitory ligands to inhibit antitumor T cell function. Blocking programmed cell death protein (PD)-1 signaling, which mediates T cell suppression via engagement of its inhibitory ligands, PD-L1 or PD-L2, is of particular interest due to recent successes in many types of cancer. In syngeneic murine rhabdomyosarcoma models, we found that M3-9-M (MHC I high) but not 76-9 (MHC I low) tumors respond to oncolytic herpes simplex virus-1 (oHSV-1) and PD-1 blockade combination therapy. In addition, the therapeutic outcomes in M3-9-M tumor models correlated with the increased incidence of CD4+ and CD8+ T cells but not with the CD4+CD25+Foxp3+ regulatory T cell populations in the tumor. Overall, our data suggest the combination of PD-1 blockade and oHSV-1 may be an effective treatment strategy for childhood soft tissue sarcoma.
Characterization of the Adult Head Transcriptome and Identification of Migration and Olfaction Genes in the Oriental Armyworm Mythimna separate
Authors: Bian Hai-Xu , Ma Hong-Fang , Zheng Xi-Xi , Peng Ming-Hui , Li Yu-Ping , Su Jun-Fang , Wang Huan , Li Qun , Xia Run-Xi , Liu Yan-Qun , Jiang Xing-Fu 
Published: May 2017

AbstractThe oriental armywormMythimna separateis an economically important insect with a wide distribution and strong migratory activity. However, knowledge about the molecular mechanisms regulating the physiological and behavioural responses of the oriental armyworm is scarce. In the present study, we took a transcriptomic approach to characterize the gene network in the adult head ofM.separate. The sequencing andde novoassembly yielded 63,499 transcripts, which were further assembled into 46,459 unigenes with an N50 of 1,153 bp. In the head transcriptome data, unigenes involved in the ‘signal transduction mechanism’ are the most abundant. In total, 937 signal transduction unigenes were assigned to 22 signalling pathways. The circadian clock, melanin synthesis, and non-receptor protein of olfactory gene families were then identified, and phylogenetic analyses were performed with theseM.separategenes, the model insectBombyxmoriand other insects. Furthermore, 1,372 simple sequence repeats of 2–6 bp in unit length were identified. The transcriptome data represent a comprehensive molecular resource for the adult head ofM.separate, and these identified genes can be valid targets for further gene function research to address the molecular mechanisms regulating the migratory and olfaction genes of the oriental armyworm.
Coupling mechanism between wear and oxidation processes of 304 stainless steel in hydrogen peroxide environments
Authors: Dong Conglin , Yuan Chengqing , Bai Xiuqin , Li Jian , Qin Honglin , Yan Xinping 
Published: May 2017

AbstractStainless steel is widely used in strongly oxidizing hydrogen peroxide (H2O2) environments. It is crucial to study its wear behaviour and failure mode. The tribological properties and oxidation of 304 stainless steel were investigated using a MMW-1 tribo-tester with a three-electrode setup in H2O2 solutions with different concentrations. Corrosion current densities (CCDs), coefficients of frictions (COFs), wear mass losses, wear surface topographies, and metal oxide films were analysed and compared. The results show that the wear process and oxidation process interacted significantly with each other. Increasing the concentration of H2O2 or the oxidation time was useful to form a layer of integrated, homogeneous, compact and thick metal oxide film. The dense metal oxide films with higher mechanical strengths improved the wear process and also reduced the oxidation reaction. The wear process removed the metal oxide films to increase the oxidation reaction. Theoretical data is provided for the rational design and application of friction pairs in oxidation corrosion conditions.